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1. Contribution of paddock trees to the conservation of terrestrial invertebrate biodiversity within grazed native pastures
• date - 2006-02
• creator - OLIVER, IAN
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01537.x
2. Roost tree characteristics determine use by the white-striped freetail bat (Tadarida australis, Chiroptera: Molossidae) in suburban subtropical Brisbane, Australia
• date - 2006-04
• creator - RHODES, MONIKA
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01587.x
• description - Abstract  We examined factors affecting roost tree selection by the white-striped freetail bat Tadarida australis (Chiroptera: Molossidae), a large insectivorous bat in suburban Brisbane, Australia. We compared biophysical characteristics associated with 34 roost trees and 170 control trees of similar diameter, height and tree senescence characters. Roost trees used by the white-striped freetail bat had significantly higher numbers of hollows in the trunk and branches (P < 0.003) and were more likely to contain a large trunk cavity with an internal diameter of >30 cm (P < 0.001) than control trees. These trees also accommodated more species of hollow-using fauna (P = 0.005). When comparing roost trees with control trees of similar diameters and heights, roost trees were on average at a later stage of tree senescence (P < 0.001). None of the roost trees were found in the large forest reserves fringing the Brisbane metropolitan area despite these areas being used for foraging by the white-striped freetail bat. Although all tree locations in this study were in modified landscapes, roost trees tended to be surrounded by groups of trees and undergrowth. Roost trees provide important habitat requirements for hollow-using fauna in suburban, rural and forested environments.
3. tree
• date - 2002-03-02
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/Tree.html
• description - Formally, a ... forest is an undirected, acyclic graph. A forest consists of ... trees , which are themselves acyclic, connected graphs. For example, the following diagram represents a forest, each connected component of which is a tree. ... All trees are forests, but not all forests are trees. As in a graph, a forest is made up of vertices (which are often called nodes interchangeably) and edges. Like any graph, the vertices and edges may each be labelled --- that is, associated with some atom of data. Therefore a forest or a tree is often used as a data structure. Often a particular node of a tree is specified as the ... root . Such trees are typically drawn with the root at the top of the diagram, with all other nodes depending down from it (however this is not always the case). A tree where a root has been specified is called a ... rooted tree . A tree where no root has been specified is called a ... free tree . When speaking of tree traversals, and most especially of trees as datastructures, rooted trees are often implied. The edges of a rooted tree are often treated as directed. In a rooted tree, every non-root node has exactly one edge that leads to the root. This edge can be thought of as connecting each node to its ... parent . Often rooted trees ae considered directed in the sense that all edges connect parents to their children, but not vice-versa. Given this parent-child relationship, a ... descendant of a node in a directed tree is defined as any other node reachable from that node (that is, a node's children and all their descendants). Given this directed notion of a rooted tree, a ... rooted subtree can be defined as any node of a tree and all of its descendants. This notion of a rooted subtree is very useful in dealing with trees inductively and defining certain algorithms inductively. Because of their simple structure and unique properties, trees and forests have many uses. Because of the simple definition of various tree traversals, they are often used to store and lookup data. Many algorithms are based upon trees, or depend upon a tree in some manner, such as the heapsort algorithm or Huffman encoding. There are also a great many specific forms and families of trees, each with its own constraints, strengths, and weaknesses.
4. red-black tree
• date - 2007-07-10
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/RedBlackTree.html
• description - A ... red-black tree is a type of self-balancing binary search tree, a data structure used in computer science, typically used to implement associative arrays. The original structure was invented in 1972 by Rudolf Bayer who called them "symmetric binary B-trees", but acquired its modern name in a paper in 1978 by Leo J. Guibas and Robert Sedgewick. It is complex, but has good worst-case running time for its operations and is efficient in practice: it can search, insert, and delete in ... time, where <i>n</i> is the number of elements in the tree. A red-black tree is a special type of binary tree, which is a structure used in computer science to organize pieces of comparable data, such as numbers. In binary trees, each piece of data is stored in a node. One of the nodes always functions as our starting place, and is not the child of any node; we call this the root node or root. It has up to two "children", other nodes to which it connects. Each of these children can have up to two children of its own, and so on. The root node thus has a path connecting it to any other node in the tree. If a node has no children, we call it a leaf node, since intuitively it is at the periphery of the tree. A subtree is the portion of the tree that can be reached from a certain node, considered as a tree itself. In red-black trees, the leaves are assumed to be null; that is, they do not contain any data. Binary search trees, including red-black trees, satisfy the constraint that every node contains a value less than or equal to all nodes in its right subtree, and greater than or equal to all nodes in its left subtree. This makes it quick to search the tree for a given value, and allows efficient in-order traversal of elements. Red-black trees, along with AVL trees, offer the best possible worst-case guarantees for insertion time, deletion time, and search time. Not only does this make them valuable in time-sensitive applications such as real-time applications, but it makes them valuable building blocks in other data structures which provide worst-case guarantees; for example, many data structures used in computational geometry can be based on red-black trees. Red-black trees are also particularly valuable in functional programming, where they are one of the most common persistent data structures, used to construct associative arrays and sets which can retain previous versions after mutations. The persistent version of red-black trees requires O(log n) space for each insertion
5. Huffman's algorithm
• date - 2006-08-12
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/HuffmansAlgorithm.html
• description - ... Huffman's algorithm is a method for building an extended binary tree with a minimum weighted path length from a set of given weights. Initially construct a forest of singleton trees, one associated with each weight. If there are at least two trees, choose the two trees with the least weight associated with their roots and replace them with a new tree, constructed by creating a root node whose weight is the sum of the weights of the roots of the two trees removed, and setting the two trees just removed as this new node's children. This process is repeated until the forest consists of one tree. ... (W, n) ... { ... Input : A list <i>W</i> of <i>n</i> (positive) weights.} ... { ... Output : An extended binary tree <i>T</i> with weights taken from <i>W</i> that gives the minimum weighted path length.} ... { ... Procedure :} ... Create list <i>F</i> from singleton trees formed from elements of <i>W</i> ... (F ... \ has more than one element ) ... Find ... , ... in <i>F</i> that have minimum values associated with their roots ... Construct new tree <i>T</i> by creating a new node and setting ... and ... as its children ... Let the sum of the values associated with the roots of ... and ... be associated with the root of <i>T</i> ... Add <i>T</i> to <i>F</i> ... \ tree stored in\ F ... Let us work through an example for the set of weights ... . In these intermediate steps we will display the temporary weights assigned by the algorithm in the circled nodes. Initially our forest is ... During the first step, the two trees with weights 1 and 2 are merged, to create a new tree with a root of weight 3. ... We now have three trees with weights of 3 at their roots. It does not matter which two we choose to merge. Let us choose the tree we just created and one of the singleton nodes of weight 3. ... Now our two minimum trees are the two singleton nodes of weights 3 and 4. We will combine these to form a new tree of weight 7. ... Finally we merge our last two remaining trees. ... The result is an extended binary tree of minimum weighted path length 29. In the following diagram each circled node is marked with its weighted path length. ... Each iteration of Huffman's algorithm reduces the size of the problem by 1, and so there are exactly <i>n</i> iterations. The <i>i</i>th iteration consists of locating the two minimum values in a list of length ... . This is a linear operation, and so Huffman's algorithm clearly has a time complexity of ... . However, it would be fast
6. Bark Consumption by the Painted Ringtail (Pseudochirulus forbesi larvatus) in Papua New Guinea 1
• date - 2006-09
• creator - Stephens, Suzette A.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2006.00197.x
• description - ABSTRACT We documented bark consumption by painted ringtails (Pseudochirulus forbesi) and other arboreal marsupials at Mt. Stolle, Papua New Guinea. Evidence consisted of scratch marks on the boles of trees in conjunction with the removal of all moss and direct sightings of animals eating bark. Only 43 trees ≥10 cm diameter at breast height (DBH) of 19 species showed signs of consumption at the study site; five of these species were confirmed by direct sighting to be consumed by painted ringtails. We sought to determine if bark of these trees contained important dietary minerals. Analyses showed that calcium and potassium, individually and combined, were significantly more abundant in eaten versus uneaten trees of the same species. On average, eaten trees showed 4.7 and 2.2 times the amount of these minerals, respectively, as found in uneaten trees. Adult males were more likely than adult females or juvenile males to be captured at eaten trees than away from them. Two species of Syzygium and one species of Sloanea were highly selected for bark consumption, but not all trees of a species were eaten; rather, particular individuals of these species were preferred. We conclude that bark appears to be an important source of calcium and potassium, and speculate on the relationship between the limited availability of these special trees and the social behavior of painted ringtails.
7. Host tree architecture mediates the effect of predators on herbivore survival
• date - 2006-06
• creator - RIIHIMÄKI, JANNE
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2311.2006.00784.x
• description - Abstract.  1. Vegetation structural complexity is an important factor influencing ecological interactions between different trophic levels. In order to investigate relationships between the architecture of trees, the presence of arthropod predators, and survival and parasitism of the autumnal moth Epirrita autumnata Borkhausen, two sets of experiments were conducted. 2. In one experiment, the architectural complexity of mountain birch was manipulated to separate the effects of plant structure and age. In the other experiment the trees were left intact, but chosen to represent varying degrees of natural complexity. Young autumnal moth larvae were placed on the trees and their survival was monitored during the larval period. 3. The larvae survived longer in more complex trees if predation by ants was prevented with a glue ring, whereas in control trees smaller canopy size improved survival times in one experiment. The density of ants observed in the trees was not affected by canopy size but spider density was higher on smaller trees. The effect of canopy structure on larval parasitism was weak; larger canopy size decreased parasitism only in one year. Until the fourth instar the larvae travelled shorter distances in trees with reduced branchiness than in trees with reduced foliage or control treatments. Canopy structure manipulation by pruning did not alter the quality of leaves as food for larvae. 4. The effect of canopy structure on herbivore survival may depend on natural enemy abundance and foraging strategy. In complex canopies herbivores are probably better able to escape predation by ambushing spiders but not by actively searching ants.
8. Crown dieback events as key processes creating cavity habitat for magellanic woodpeckers
• date - 2007-06
• creator - OJEDA, VALERIA S.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01705.x
• description - Abstract  Woodpeckers are considered keystone species for webs of cavity nesters and habitat and resource specialists that strongly depend on availability of trees suitable for cavity excavation. Most studies carried out in northern hemisphere temperate coniferous forests emphasize the importance of old growth stages of forests or large dead trees as habitat for cavity builders. We present a study of Nothofagus pumilio tree selection by the magellanic woodpecker (Campephilus magellanicus) that incorporates dendroecological data on long-term growth trends of trees that provides new insights into the processes that create suitable habitat for cavity excavating species. We analysed 351 cavity and neighbouring control trees in terms of age and radial growth patterns, as well as external tree characteristics. In addition, from a subsample of these trees we developed tree-ring chronologies for each group using standard methods in order to analyse potential differences in radial growth patterns between cavity and non-cavity trees. Multivariate models that account for differences between paired cavities versus control trees indicated that growth decline and the degree of crown dieback were the primary variables explaining magellanic woodpecker tree selection for cavity building. In contrast to previous work, neither diameter (above a certain threshold) nor age, were important determinants of selection. Furthermore, trees that became present cavity are those that had synchronously declined in radial growth during the 1943–44 and 1956–57 droughts and the 1985–86 massive caterpillar defoliation. Insect outbreaks and extreme climatic events may episodically reduce vigour, induce partial crown mortality, trigger increased fungal attack and heart rot formation at different tree heights on the bole in a group of trees and thus increase availability of soft substrate and their likelihood of cavity excavation by the magellanic woodpecker. These results underscore the importance of drought/biotically-induced canopy dieback events in creating habitat for woodpeckers and their dependent cavity users.
9. Ecohydrology of a seasonal cloud forest in Dhofar
• date - 2006-02-02T18:51:37Z
• creator - Hildebrandt, Anke, 1975-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/31135
• description - (cont.) The same model is used to investigate the role of the soil in controlling relative performance of trees and grass in this ecosystem. A characteristic rooting depth that is optimal for tree growth is identified, function of soil type and climate. This is the smallest depth at which transpiration is maximized and all other water sinks such as surface runoff or drainage are minimized. The optimal rooting depth is deeper when the evaporative demand during the wet season is low, similar to conditions in Dhofar. Such conditions improve competitiveness of trees in the model simulations. A horizontal precipitation module is used to illustrate how the contribution of this process is markedly reduced over grass as compared to trees. When the horizontal precipitation module is coupled to the vegetation model, two stable states are simulated by the model. Equilibrium vegetation simulated by the model starting from forest (grass) initial conditions is dominated by trees (grass). Deforestation, in the model, reduces soil water input and hence would tend to inhibit re-emergence of trees as a dominant land cover. Implications of this feedback for the re-forestation efforts in Dhofar are discussed. The results of this study should provide a solid basis for sound environmental management of the ecosystem.
10. A quantitative analysis of plant community structure in an abandoned rubber plantations on Kho-Hong Hill, southern Thailand
• date - 2006
• creator - Charan Leelatiwong
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2006&volume=28&issue=3&spage=479
• description - The present study aimed to characterize plant community structure of rubber plantations abandoned 26 years previously and now a protected area of Prince of Songkla University on the west slope of Kho-Hong Hill. Trees whose girth at breast high were at least 30 cm were recorded from thirty-one plots (10*10 m) which were laid out systematically at every 100 m along three transects. Among native trees, this plant community is dominated by Schima wallichii Choisy, Castanopsis schefferiana Hance, Memecylon edule Roxb., Diospyros frutescens Blume, and Diplospora malaccensis Hook.f. Trees of the families Myrtaceae, Theaceae, Clusiaceae, Fagaceae, and Rubiaceae, and saplings of Clusiaceae, Myrtaceae, Theaceae, Rubiaceae and Euphorbiaceae were the most common. This plant community was characterized as a late seral stage post-cultivation succession. The basal area of rubber trees was positively significantly related to the species richness of native trees but negatively related to the density of native trees in each plot. Although abandoned rubber plantations create environmental conditions which effectively catalyze forest succession, dense rubber trees could slow succession of native trees by competition for resources. Further ecological, educational and recreational studies are discussed. Zoning this area to be a strict nature reserve and a conservation area is recommended.
11. number of unrooted labeled trees
• date - 2007-09-01
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/NumberOfUnrootedLabeledTrees.html
• description - ... (Cayley) The number of [isomorphism classes of] labeled trees on <i>n</i> vertices ... is ... . ... This is sequence A000272 in the http://www.research.att.com/~njas/sequences For ... and ... the result is obvious. For ... , the possible trees are ... while for ... , the ... trees fall into two groups: ... trees with linear structure and <i>4</i> with a star structure. There are ... linear trees since there are ... orderings of ... and mirror orderings give the same tree; there are <i>4</i> star trees since the tree is determined by its central element. There are many proofs of this theorem; the demonstration we give uses the ... Pr\"ufer bijection , which associates with each such tree its ... Pr\"ufer code ; it is easily seen that the number of Pr\"ufer codes on ... is ... . A ... Pr\"ufer code on ... is a sequence of ... elements ... chosen from ... (repetitions are allowed). Obviously there are ... codes on <i>n</i> symbols. Given a tree <i>T</i> on ... with ... , convert it to a Pr\"ufer code using the following algorithm: ... for ... to ... let ... be the vertex in <i>T</i> with the smallest label ... let ... be the vertex adjacent to ... remove ... from <i>T</i> ... next <i>j</i> } When this process completes, the result will be a Pr\"ufer code (of length ... ) on <i>n</i> symbols; this mapping is clearly well-defined. Let's walk through a more complicated example. Consider the following tree on <i>8</i> vertices: ... Using the algorithm above, we get ... c|c ... & ... <i>4</i> & <i>1</i> <i>5</i> & <i>1</i> <i>6</i> & <i>3</i> <i>3</i> & <i>1</i> <i>1</i> & <i>2</i> <i>7</i> & <i>2</i> ... and thus the Pr\"ufer code associated with this tree is ... . The easiest way to see that this map is a bijection is by explicitly constructing its inverse. To do this, we must show how to construct a tree <i>T</i> on ... given a Pr\"ufer code on <i>n</i> symbols. Note first that the code for a given tree contains only the non-leaf vertices, and that each non-leaf vertex appears at least once in the code. The first of these statements is obvious from the algorithm - given that ... and since the algorithm stops when there are only two vertices left in the tree, no leaf vertex in the original tree can be selected as an ... . To see that every non-leaf must appear in the list, note that each vertex was either removed as one of the ... or it remains in the two-vertex tree at the end of the process. In either event, one of its adjacent vertices was removed from th
12. Reliability of Multi-Terminal Copper Dual-Damascene Interconnect Trees
• date - 2003-11-29T19:49:07Z
• creator - Gan, C.L.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/3730
• description - Singapore-MIT Alliance (SMA)
13. Protecting Trees During Construction
14. Sequential patterns of colonization of coarse woody debris by Ips pini (Say) (Coleoptera: Scolytidae) following a major ice storm in Ontario
• date - 2006-05
• creator - Ryall, K. L.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1461-9555.2006.00287.x
• description - Abstract  1 It is widely known that many bark and wood-boring beetle species use nonresistant coarse woody debris (CWD) created by disturbances; however, the ability of these secondary species to cause mortality in healthy trees following a build-up of their populations remains unclear. We characterized the pattern of colonization by Ips pini (Say) following a major ice storm that created large amounts of CWD varying in resistance to colonization (i.e. ranging from snapped tops with no resistance to heavily damaged trees with intact root systems). A major question was how the beetles responded to the different types of storm-damaged material and whether healthy undamaged trees were colonized and killed following increases in beetle populations. 2 Six red pine, Pinus resinosa Ait., plantations in eastern Ontario were monitored from 1998 to 2001 inclusive: three with high storm damage (approximately 120 m3/ha CWD) and three with minimal damage (approximately 20 m3/ha CWD). Transects (200 × 2 m) were sampled yearly in each plantation to assess the type and amount of damaged pine brood material colonized by the pine engraver beetle, I. pini. 3 Beetles preferentially infested the most nonresistant material available each year (i.e. all snapped tops in year 1, all standing snags, up-rooted trees and many bent trees by year 2, but still less than 50% of trees blown over but with intact root systems by year 3). By years 3 and 4, the majority (approximately 75%) of severely damaged trees (with > 50% crown loss) died prior to beetle colonization. 4 The size of the beetle population tracked the abundance of available woody material from year-to-year within a plantation; populations were very large in the first 2 years, and declined significantly in the last 2 years. 5 Healthy standing red pines were apparently resistant to colonization by the beetles, despite the significant build-up in their populations. Hence, the results of the present study suggest that native bark beetle populations will not cause further tree mortality following such a disturbance in this region.
15. NGM_CD4
• date -
• creator -
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - A tree is a perennial woody plant. It is sometimes defined as a woody plant that attains diameter of 10 cm (30 cm girth) or more at breast height (130 cm above ground).[1] However, there is no set agreement regarding minimum size, the term generally applies to plants that grow to at least 5-6 meters (15-20 ft) high at maturity[citation needed] and having secondary branches supported on a main stem or stems, called a trunk. Most trees exhibit clear apical dominance, though this is not always the case.[2] Compared with most other plants, trees are long-lived, some of them getting to be several thousand years old and growing to up to 115 meters (375 ft) high. Trees are an important component of the natural landscape because of their prevention of erosion and the provision of a specific weather-sheltered ecosystem in and under their foliage. Trees have also been found to play an important role in producing oxygen[citation needed] and reducing carbon dioxide in the atmosphere, as well as moderating ground temperatures. They are also significant elements in landscaping and agriculture, both for their aesthetic appeal and their orchard crops (such as apples). Wood from trees is a common building material. Trees also play an intimate role in many of the world's mythologies (see trees in mythology).
16. Wood Flooring in Sustainable Design
• date - 2007-02
• creator - Bill Christensen, Webmaster and Founder Sustainable Sources, City of Austin, Texas
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=44B8B721-2F82-4977-975C-4B53FA72D19E
• description - "Wood flooring in this section refers to finish floors that can be in strips or parquet and nailed or glued to a subfloor. Wood flooring is considered an aesthetic plus to homes. It also offers long life and fairly easy maintenance. Most wood flooring is derived from hardwood trees. From an overall view, the growth/removal rate for hardwood trees in the U. S. is positive with growth easily exceeding removals. The use of regional hardwoods such as mesquite stimulates the regional economy and uses a tree considered a nuisance by many. Mesquite trees are often subject to chemical eradication programs rather than used constructively. Mesquite hardwood is highly valued as a floor material. However, the tree does not produce large consistent-size logs, increasing the costs of processing it. Reused wood flooring is often derived from remilled salvage timbers. It can also be salvaged from old flooring. From an environmental standpoint, this approach saves materials from the wastestream and does not impact living trees. Very often the reused wood flooring comes from trees that are no longer present to harvest, or in grain patterns only found in rare old large trees. This adds to the aesthetic quality of this type of flooring. The finishes selected for wood flooring and any adhesives used should contain low VOC content." Online resource for green building design by the City of Austin, Texas offering practical information needed to implement green building practices to architects, builders, and homeowners in seeking to create sustainable buildings. The site is organized around the following topics: DEFINITIONS, CONSIDERATIONS, COMMERCIAL STATUS, IMPLEMENTATION ISSUES, GUIDELINES RESOURCES, PROFESSIONAL ASSISTANCE, COMPONENTS / MATERIALS / SYSTEMS, GENERAL ASSISTANCE, and INTERNET RESOURCES.
17. Effects of irrigation on physiological responses and latex yield of rubber trees (Hevea brasiliensis) during the dry season
• date - 2007
• creator - Yeedum, I.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/29-3_online/0125-3395-29-3-0601-0613.pdf
• description - To invegestigate the effects of irrigation on physiological responses and latex yield of rubber trees during the dry season (February-May 2006), 14 year-old rubber trees (RRIM 600 clone), grown at The-PhaResearch Station in Songkhla Province were used. An experiment was arranged in a randomized complete block design in 3 treatments and 3 replications. The treatments were as follows: 1) control or rainfed condition(T1), 2) under irrigation regime of 1.00 ETc or crop evapotranspiration (T2) and 3) under irrigation regime of 0.50 ETc (T3). Irrigation caused marked leaf-shedding in T2 and T3, res-pectively, compared in T1. Thiscaused the production of new leaves in T3 and T2 to be about 10 and 20 days, respectively, later than in T1. In the middle of March, leaf density in T2 greatly increased as compared to T3 and T1, respectively. It wasfound that diurnal changes of leaf water potential and stomatal conductance of the rubber leaves of trees in T1 trended to be lower than those in T2 and T3 during the experimental period. However, there were no significant differences among the treatments. It was also found that the irrigated trees in T2 had significantlyhigher latex yields than the trees in T1 by about 18-25%, while there were no significant differences between T1 and T3. There were no significant differences in dry rubber content (DRC) among the three treatments,the average DRC being about 39%.
18. Applying Network Analysis to the Conservation of Habitat Trees in Urban Environments: a Case Study from Brisbane, Australia
• date - 2006-06
• creator - RHODES, MONIKA
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.2006.00415.x
• description - Abstract:  In Australia more than 300 vertebrates, including 43 insectivorous bat species, depend on hollows in habitat trees for shelter, with many species using a network of multiple trees as roosts. We used roost-switching data on white-striped freetail bats (Tadarida australis; Microchiroptera: Molossidae) to construct a network representation of day roosts in suburban Brisbane, Australia. Bats were caught from a communal roost tree with a roosting group of several hundred individuals and released with transmitters. Each roost used by the bats represented a node in the network, and the movements of bats between roosts formed the links between nodes. Despite differences in gender and reproductive stages, the bats exhibited the same behavior throughout three radiotelemetry periods and over 500 bat days of radio tracking: each roosted in separate roosts, switched roosts very infrequently, and associated with other bats only at the communal roost. This network resembled a scale-free network in which the distribution of the number of links from each roost followed a power law. Despite being spread over a large geographic area (>200 km2), each roost was connected to others by less than three links. One roost (the hub or communal roost) defined the architecture of the network because it had the most links. That the network showed scale-free properties has profound implications for the management of the habitat trees of this roosting group. Scale-free networks provide high tolerance against stochastic events such as random roost removals but are susceptible to the selective removal of hub nodes. Network analysis is a useful tool for understanding the structural organization of habitat tree usage and allows the informed judgment of the relative importance of individual trees and hence the derivation of appropriate management decisions. Conservation planners and managers should emphasize the differential importance of habitat trees and think of them as being analogous to vital service centers in human societies.
19. Trees, shrubs and flowers for Florida landscaping [electronic resource] : native and exotic / by Julia F. Morton.
20. Regulating irrigation during pre-harvest to avoid the incidence of translucent flesh disorder and gamboge disorder of mangosteen fruits
• date - 2005
• creator - Sayan Sdoodee
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27-5-pdf/03-mangosteen.pdf
• description - In humid tropical areas, excess water during pre-harvest usually causes the occurrence of translucent flesh disorder (TFD) and gamboge disorder (GD) in mangosteen. To evaluate options for avoiding these incidences, an experiment was conducted with different water management regimes during pre-harvest. Twelve 14-year-old trees were grown under transparent plastic cover with three irrigation regimes: 1) Control (rainfed condition), 2) 7-d interval watering, 3) 4-d interval watering and 4) daily watering. A further four trees were arranged as the control (rainfed) treatment, but these were grown without the plastic roof cover. The treatments were started at 9 weeks after bloom. The results showed that diurnal changes of leaf water potential and stomatal conductance were lowest in the control, because intermittent drying occurred during the study period. The highest fruit diameter, fruit weight, flesh firmness and flesh and rind water contents were found in the daily watering treatment. However, all of these values were lowest in the control trees. The amount of TFD was also lowest in the control (3.7%), and it was significantly different from the treatment where trees were watered at 4-d intervals (18.0%) and where trees were watered daily (28.9%). There was no significant difference of TFD between the control and the 7-d interval watering treatments. In contrast, GD was not significantly different among the treatments. It is suggested that the risk of TFD and GD incidence could be avoided by maintaining mild soil water deficit around -70 kPa during pre-harvest.
21. Protecting Trees from Construction Damage: A Homeowners Guide.
22. The molecular weight (MW) and molecular weight distribution (MWD) of NR from different age and clone Hevea trees
• date - 2005
• creator - Saovanee Kovuttikulrangsie
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27-2-pdf/11natural-rubber.pdf
• description - NR-latex was tapped from different age and clone Hevea trees. The latex of virgin started from 3 years trees was transesterified to reduce the branching molecules. The molecular weight (MW) and molecular weight distribution (MWD) of rubber molecules were measured using a gel-permeation chromatography (GPC). It was found that variation in MW and MWD of natural rubber depended on the age and clone of rubber tree. An increased age of rubber clone BPM 24 (3, 5 and 8 years) and KRS 156 (1, 15 and 25 years) also increased the MW and MWD of rubber. Nine different clones of 8 months young virgin trees (NATAWE 208, AVROS 2037, RRIC 6, GT-1, PR 255, PR 261, KRS 156, BPM 24 and RRIM 600) showed a unimodal distribution with a small variation in MW and narrow MWD. On the other hand, those regularly tapped mature trees (NATAWE 208, AVROS 2037, RRIC 6, GT-1, PR 255, PR 261 and KRS 156) aged 25 years, showed a great variation in MW and MWD. The Mw value of NR showed a great variation from about 104 to 106. The polydispersity ( Mw / Mn) was between 2 and 11.
23. Building With Trees Program
• date - 2004
• creator -
• provider - NSDL OAI Repository
• location - http://www.arborday.org/Programs/BuildWTrees.html
• description - Tree protection guidelines for builders. Provides opportunities for builders and developers to receive recognition for their efforts in protecting existing trees during the planning, design, and construction of new buildings.
24. The relationship between rainfall, water source and growth for an endangered tree
• date - 2007-06
• creator - FEBRUARY, EDMUND C.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01711.x
• description - Abstract  It is now reasonably well understood that the human impact on the environment since industrialization has led to significant changes in climate. Here we attempt to develop a predictive understanding of the effects that future changes in climate may have on vegetation structure and species diversity. We do this through a determination of the relationship between radial growth and water source for Widdringtonia cedarbergensis Marsh. Our results show that there was no significant relationship between monthly radial growth, as determined using dendrometer bands, and rainfall. There is, however, a significant relationship between the δ18O composition of the water extracted from the trees and the rain δ18O values. We speculate that W. cedarbergensis exploits water derived from rain that flows off the rocky substrate of the study area into sumps between the bedding planes of the rocks on which they grow. This runoff occurs rapidly during rain events resulting in δ18O values for the trees sourcing this water not to be significantly different from that of the rain. Rainfall therefore has to be sufficient to refill these sumps on which the trees are dependent. The dendrometer bands reflect a slow but steady growth of the trees at the study site. While this growth is not dependent on rainfall, it is dependent on reliable access to available water. If climate change predictions for the region are realized and rainfall is reduced then this species will be affected. W. cedarbergensis is endemic to only a very small area within the Cedarberg Mountains in South Africa and is also one of the few trees growing in the fynbos. The extinction of this species in the wild will fundamentally affect both the vegetation structure and species composition of the region.
25. Simplifying Decision Trees
• date - 2004-10-04T14:56:58Z
• creator - Quinlan, J.R.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6453
• description - Many systems have been developed for constructing decision trees from collections of examples. Although the decision trees generated by these methods are accurate and efficient, they often suffer the disadvantage of excessive complexity that can render them incomprehensible to experts. It is questionable whether opaque structures of this kind can be described as knowledge, no matter how well they function. This paper discusses techniques for simplifying decision trees without compromising their accuracy. Four methods are described, illustrated, and compared on a test- bed of decision trees from a variety of domains.
26. Efficient classical simulation of spin networks
• date - 2007-02-21T11:26:50Z
• creator - Sylvester, Igor Andrade
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36112
• description - Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.
27. Spatial patterns and environmental factors affecting the presence of Melampsorella caryophyllacearum infections in an Abies alba forest in NE Spain
• date - 2006-06
• creator - S olla , A.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1439-0329.2006.00446.x
• description - Summary The presence of trunk swellings caused by the rust fungus Melampsorella caryophyllacearum was systematically surveyed in an Abies alba forest (Irati, NE Spain), using 1237 circular plots (diameter = 18 m). The relationship between fungal presence and several abiotic (aspect, elevation, distance to the nearest river and slope) and biotic factors (basal area of A. alba and/or Fagus sylvatica, shrub, fern and herb cover) was assessed through correlation and ordination analyses. Additionally, the spatial pattern of the presence of diseased trees was described using Ripley's K function. Southern-aspect plots had a significantly lower presence of diseased trees than plots-oriented north, east and west. Plots with diseased trees were located at a significantly lower elevation, and at a shorter distance to the river than plots without infections. Plots with diseased trees had almost twice the average A. alba basal area, and less average F. sylvatica basal area than plots without diseased trees. However, similar mean values of slope and shrub, fern and herb cover were found in both types of plots. The disease showed spatial aggregation in patches with a mean radius of ca. 900 m. The implications of the results for disease management are discussed.
28. Low Inbreeding and High Pollen Dispersal Distances in Populations of Two Amazonian Forest Tree Species
• date - 2007-05
• creator - Cloutier, Dominic
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00266.x
• description - ABSTRACT Recent studies suggest that tropical tree species exhibit low inbreeding and high gene dispersal levels despite the typically low density of conspecifics in tropical forests. To examine this, we undertook a study of pollen gene dispersal and mating system of two Amazonian tree species. We analyzed 341 seeds from 33 trees at four microsatellite loci in a Carapa guianensis population from Brazil, and 212 seeds from 22 trees at four microsatellite loci in a Sextonia rubra population from French Guiana. Differentiation of allele frequencies among the pollen pool of individual trees was ΦFT= 0.053 (95% CI: 0.027–0.074) for C. guianensis and ΦFT= 0.064 (95% CI: 0.017–0.088) for S. rubra. The mean pollen dispersal distances were estimated at 69–355 m for C. guianensis, and 86–303 m for S. rubra, depending on the pollen dispersal model and the estimate of reproductive tree density used. The multi-locus outcrossing rate was estimated at 0.918 and 0.945, and the correlation of paternity at 0.089 and 0.096, for C. guianensis and S. rubra, respectively, while no significant levels of biparental inbreeding were detected. Comparing trees with high and low local density of conspecifics, we found no evidence for differences in inbreeding levels. The results are discussed within the framework of the emerging picture of the reproductive biology of tropical forest trees.
29. Analyzing the effects of asymmetric unicast routes on multicast routing protocols
• date - 2001
• creator - Costa Luís Henrique M. K.
• provider - NSDL OAI Repository
• location - http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-65002001000100002
• description - Different multicast routing protocols construct their distribution trees based on the information obtained from the unicast routing infrastructure. Nevertheless, the design of most of these protocols do not take into account that unicast routes may be asymmetric. Indeed, unicast routes in the Internet are very asymmetric. The effects on the quality of the multicast trees vary according to the routing protocol. These are particularly important for protocols that use the recursive unicast approach to allow the progressive deployment of the multicast service. This paper analyses the effects of asymmetric unicast routing on different multicast protocols. We concentrate on two approaches that implement the multicast service trough recursive unicast trees, HBH (Hop-By-Hop multicast routing protocol) and REUNITE (Recursive UNIcast TrEes). Both protocols construct source-specific trees exclusively, which simplify address allocation. As data packets have unicast destination addresses, pure unicast routers are transparently supported. The branching-nodes recursively create packet copies to implement the distribution. Nevertheless, the tree construction algorithms implemented by HBH and REUNITE are different. The design of HBH takes into account the unicast routing asymmetries of the network. HBH is able to always construct a Shortest-Path Tree. Consequently, HBH provides shorter delay routes in asymmetric networks, and provides smaller bandwidth consumption because useless data duplication is avoided. The results obtained from simulation show the effects of unicast routing asymmetries in the different multicast protocols.
30. Role of nurse plants in Araucaria Forest expansion over grassland in south Brazil
• date - 2006-06
• creator - DUARTE, LEANDRO DA S.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01602.x
• description - Abstract  Araucaria Forest expansion over grassland takes place under wet climate conditions and low disturbance and it is hypothesized that isolated trees established on grassland facilitate the establishment of forest woody species beneath their canopies. Forest with Araucaria angustifolia is a particular type of Brazilian Atlantic Forest and the main forest type on the highland plateau in south Brazil, often forming mosaics with natural Campos grassland. The objectives of this paper were to evaluate the role of isolated shrubs and trees as colonization sites for seedlings of Araucaria Forest woody species on grassland, to determine which species function as preferential nurse plants in the process and the importance of vertebrate diaspore dispersal on the structure of seedling communities beneath nurse plants. The study was conducted in São Francisco de Paula, Rio Grande do Sul State, where we sampled isolated shrubs and trees in natural grassland near Araucaria Forest edges. Seedlings were counted and identified, and seedling diaspore dispersal syndromes, size and colour were registered. We detected 11 woody species with a potential role in nucleating grassland colonization by forest species. Beneath the canopies of nurse plants more forest species seedlings were found compared with open field grassland and the seedlings had diaspores mostly dispersed by vertebrates. Also, more seedlings were found under the canopy of A. angustifolia than beneath other nurse plant species. We conclude that A. angustifolia trees established on grassland act as nurse plants, by attracting disperser birds that promote colonization of the site by other forest species seedlings, and that under low level of grassland disturbance, conservation of frugivorous vertebrate assemblages may increase forest expansion over natural grassland and also facilitate the regeneration of degraded forest areas.
31. Biomechanical Effects of Trees on Soil and Regolith: Beyond Treethrow
• date - 2006-06
• creator - Phillips, Jonathan D.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1467-8306.2006.00476.x
• description - Forest soils are profoundly influenced by the biomechanical as well as the chemical and biological effects of trees. Studies of biomechanical impacts have focused mainly on uprooting (treethrow), but this study shows that at least two other effects are significant: physical displacement of soil by root growth, and infilling of stump rot pits. Rocky soils in the Ouachita Mountains in Arkansas were studied because they allow for the use of rock fragments as a tracer of displacement. Rock fragments displaced by tree growth (baumsteins) are ubiquitous here, and displacement shows characteristic differences between pines and hardwoods. Hardwoods promote primarily lateral displacement, with a higher probability of displaced rock fragments eventually falling into stump holes. Pine displacement has a significant vertical component associated with basal mounding, and a lower probability of baumstein deposition in stump holes. Obvious stump holes are relatively rare, but the high ratio of stumps and snags to uprooted trees indicates that standing dead trees, which would ultimately result in a stump hole, are quite common. This, plus the presence of numerous duff-filled depressions, suggests that such holes are filled rapidly. The presence of surface-derived rock fragments and thick litter and duff accumulations indicate that at least some of the fill is external, as opposed to soil detachment from the pit walls. The primary influence of stump holes, as reflected by rock fragment distributions, is localized subsurface stone accumulations that do not extend laterally. The total area affected by uprooting is larger than that of stump holes, despite the lower frequency, due to the greater area of disturbance per event. Estimated turnover times (time for 100 percent of the forest floor to be affected) are shortest for soil displacement, intermediate for uprooting, and longest for stump hole effects. Although contemporary rates cannot be confidently extrapolated, the geomorphological efficacy of these processes is reflected by the fact that they are rapid enough to result in complete regolith turnover over time scales comparable to the Holocene. Displacement, stump holes, and uprooting help to maintain a continuously mixed surface biomantle, and may in some cases result in distinctive pedological features, local spatial variations in soil morphology, and divergent evolution of the soil cover.
32. Design of a tree moving and planting device
• date - 2007-03-12T17:50:28Z
• creator - Nabar, Sean J
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36752
• description - Planting trees that weigh over 200 pounds normally requires three or more able persons. Therefore, a device that allows a single person to easily and efficiently plant such trees possible by one person is highly desirable. During a Product Design class in the Mechanical Engineering Department at the Massachusetts Institute of Technology, a group of 14 students developed a series of four concept models which culminated in a Final Prototype of such a product that can successfully lift, move and plant trees of over 200 pounds. This paper is aimed at documenting this series of designs and analyzing, testing and further developing the Final Prototype built in the course in order to make it marketable. Based on customer feedback, testing results, and user interaction, revisions to the next prototype of this device are proposed. Testing with trees of 170 and 370 lbs determined that the current outrigger stabilizing mechanism needs modification. The current outriggers, which are stored inside the frame, sustained maximum loads of 29 lbs for the 170 lbs tree, and 46 lbs for the 370 lbs tree. A sketch model built to simulate the outrigger mechanism suggests that the outriggers should be attached outside the base frame of the device rather than stored inside.
33. binary tree
• date - 2004-05-20
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/BinaryTree.html
• description - A ... binary tree is an ordered rooted tree where every node has two or fewer children. A ... balanced binary tree is a binary tree that is also a balanced tree. For example, ... is a balanced binary tree. The two (potential) children of a node in a binary tree are often called the ... left and ... right children of that node. The left child of some node <i>X</i> and all that child's descendents are the ... left descendents of <i>X</i>. A similar definition applies to <i>X</i>'s ... right descendents . The ... left subtree of <i>X</i> is <i>X</i>'s left descendents, and the ... right subtree of <i>X</i> is its right descendents. Since we know the maximum number of children a binary tree node can have, we can make some statements regarding minimum and maximum depth of a binary tree as it relates to the total number of nodes. The maximum depth of a binary tree of <i>n</i> nodes is ... (every non-leaf node has exactly one child). The minimum depth of a binary tree of <i>n</i> nodes ( ... ) is ... (every non-leaf node has exactly two children, that is, the tree is balanced). A binary tree can be implicitly stored as an array, if we designate a constant, maximum depth for the tree. We begin by storing the root node at index <i>0</i> in the array. We then store its left child at index <i>1</i> and its right child at index <i>2</i>. The children of the node at index <i>1</i> are stored at indices <i>3</i> and <i>4</i>, and the chldren of the node at index <i>2</i> are stored at indices <i>5</i> and <i>6</i>. This can be generalized as: if a node is stored at index <i>k</i>, then its left child is located at index ... and its right child at ... . This form of implicit storage thus eliminates all overhead of the tree structure, but is only really advantageous for trees that tend to be balanced. For example, here is the implicit array representation of the tree shown above. ... |*{7 c| } ... A&B&E&C&D&F&G ... Many data structures are binary trees. For instance, heaps and binary search trees are binary trees with particular properties.
34. Abundance of Gall Midges on Poulsenia armata (Moraceae): Importance of Host Plant Size and Light Environment in Tropical Rain Forests 1
• date - 2006-07
• creator - Quesada, M.
• provider - NSDL OAI Repository
• location - Biotropica 38(4), 569-573.
• description - ABSTRACT We studied the effects of contrasting light environments on the relationship between the host plant size of Poulsenia armata and the abundance of two gall midges in a tropical rain forest in Veracruz, Mexico. The number and density of two gall morphs (i.e., laminar and vein-petiole galls) were positively correlated with plant size only in trees found in the forest but not in gaps. The availability of foliar area of P. armata trees was greater in forest gaps than in the forest. The foliar area was positively correlated with the abundance of laminar galls in trees in forest sites, but not with vein-petiole galls. We concluded that the abundance of two morphs of gall midges on P. armata was associated with host plant size only in the forest trees. Larger plants had more galls than small plants, although this relationship was affected by local light environments.
35. External-memory search trees with fast insertions
• date - 2007-04-03T17:09:55Z
• creator - Nelson, Jelani (Jelani Osei)
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/37084
• description - This thesis provides both experimental and theoretical contributions regarding external-memory dynamic search trees with fast insertions. The first contribution is the implementation of the buffered repository B-tree, a data structure that provably outperforms B-trees for updates at the cost of a constant factor decrease in query performance. This thesis also describes the cache-oblivious lookahead array, which outperforms B-trees for updates at a logarithmic cost in query performance, and does so without knowing the cache parameters of the system it is being run on. The buffered repository B-tree is an external-memory search tree that can be tuned for a tradeoff between queries and updates. Specifically, for any E [1/ lg B, 1] this data structure achieves O((1/EBl-E)(1 + logB(N/B))) block transfers for INSERT and DELETE and 0((/(1 + logB(N/B))) block transfers for SEARCH. The update complexity is amortized and is O((1/e)(1 + logB(N/B))) in the worst case. Using the value = 1/2, I was able to achieve a 17 times increase in insertion performance at the cost of only a 3 times decrease in search performance on a database with 12-byte items on a disk with a 4-kilobyte block size.
36. ABUNDANCE - Grow Sheffield - Anne-Marie Culhane
• date -
• creator -
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Environmental Artist Anne-Marie Culhane leads ABUNDANCE with apple tree diviner and gardener Steven Watts with artist Jo Salter. It forms part of Grow Sheffield and involves the mapping of fruit trees across the city of Sheffield in the UK, harvesting any unharvested trees then giving the fruit away to the community. Watts has the ability to 'divine' apple and other fruit trees - artist Anne-Marie Culhane after working with Watts can now also find apple trees even when they are on derelict industrial sites and deeply hidden. This piece highlights many issues around food production and place through the joining of artistic performative action with actual community action.
37. Interactive Flora
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.flora.sanbi.org/
• description - SANBI's Interactive Flora site consists of three datasets: Interactive Flora of Southern and Southern Tropical Africa; Trees of Southern Africa; and Interactive Mesembs. Interactive Flora of Southern and Southern Tropical Africa covers the southern African subcontinent including Namibia, Botswana, South Africa, Swaziland, Lesotho, Angola, Zambia, Zimbabwe, Malawi and Mozambique. Through an on-line catalogue of names in an hierarchical Internet classification system with identification keys, the project aims to provide the taxonomic core for southern Africa��������s flora. Trees of South Africa includes any tree, erect shrub, scrambling shrub, or woody climber with a woody main stem reaching a height up to 2 m and higher. It covers the entire spectrum of tree forms, including gymnosperms such as the yellowwoods, rare cycads, tree ferns, succulent trees such as baobabs, tree-like monocots such as certain strelitzias, as well as the rare indigenous palms, estuarine mangrove species, spiny trees, and many others. They are represented in 105 plant families, 438 genera, 1,537 species (subspecies and varieties included), and 672 synonyms. The product supports a comprehensive core data set enriched with images and maps as well as an easy on-line key to tree genera. Interactive Mesembs is a comprehensive illustrated nomenclatural database with added biogeographic information for the succulent plant family Mesembryanthemaceae (Aizoaceae: Mesembryanthemoideae & Ruschioideae).
38. An Ant Mosaic Revisited: Dominant Ant Species Disassemble Arboreal Ant Communities but Co-Occur Randomly
• date - 2007-05
• creator - Sanders, Nathan J.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00263.x
• description - ABSTRACT The spatial distributions of many tropical arboreal ant species are often arranged in a mosaic such that dominant species have mutually exclusive distributions among trees. These dominant species can also mediate the structure of the rest of the arboreal ant community. Little attention has been paid to how diet might shape the effects of dominant species on one another and the rest of the ant community. Here, we take advantage of new information on the diets of many tropical arboreal ant species to examine the intra- and inter-guild effects of dominant species on the spatial distribution of one another and the rest of the tropical arboreal ant community in a cocoa farm in Bahia, Brazil. Using null model analyses, we found that all ant species, regardless of dominance status or guild membership, co-occur much less than expected by chance. Surprisingly, the suite of five dominant species showed random co-occurrence patterns, suggesting that interspecific competition did not shape their distribution among cocoa trees. Across all species, there was no evidence that competition shaped co-occurrence patterns within guilds. Co-occurrence patterns of subordinant species were random on trees with dominant species, but highly nonrandom on trees without dominant species, suggesting that dominant species disassemble tropical arboreal ant communities. Taken together, our results highlight the often complex nature of interactions that structure species-rich tropical arboreal ant assemblages.
39. The electromigration drift velocity and the reliability of dual-damascene copper interconnect trees
• date - 2006-03-24T18:21:47Z
• creator - Wei, Frank L. (Frank Lili), 1977-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30124
• description - by Frank L. Wei.
40. Rescuing an Endangered Tree
• date -
• creator - Nemecek
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8547879F-7FEA-443F-9FF6-943F55BD8E6&ARTICLEID_CHAR=60E27E32-A493-4FEB-87D5-97C1B1769AB
• description - The number of stinking yew trees, named for the pungent odor of their needles, has been dropping since the 1950s. Today the tree (Torreya taxifolia) is considered one of the rarest in North America, with only about 1,500 specimens still alive. Efforts to preserve the tree have a particular urgency: the stinking yew is related to the Pacific yew, known for the anticancer drug taxol found in its bark. But only recently have botanists identified what is killing the trees.Gary Strobel of Montana State University, Jon Clardy of Cornell University and their colleagues report in Chemistry & Biology that the dying trees, also known as Florida torreya, are infected with the fungus Pestalotiopsis microspora, which belongs to a group of microorganisms known as endophytic fungi. Although not all endophytic fungi harm their hosts, according to Strobel the type living inside torreya trees appears to be on the edge between symbiotic and pathogenic.
41. Look-Ahead Strategies in One Person Games with Randomly Generated Game Trees
• date - 2004-10-01T20:49:28Z
• creator - Johnson, David S.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5847
• description - A random method for generated binary trees is presented, ad twp forms of a class of one person games called, "Tree Solitaire" which have such trees as their game trees are defined. After what "look ahead strategy" means in terms of such games is discussed, as theorem on the most efficient use of unlimited look-ahead is proved, and a collection of strategies involving 0, 1, or 2 look-ahead per move is introduced. A method involving diagrams is presented for calculation the probability of winning under the various strategies over a restricted class of games. The superiority of one of the l look-ahead strategies over the other is proved for games of the first form on this restricted class. For games of the second form of this class, all the introduced strategies have their chances of winning calculated, and these results are compared among themselves, with the result for the first form of the game, and with the results of Monte Carlo estimation of the chance of winning in a particular case. An approximate methods for evaluating strategies form any given position is introduced, used to explain some of the previous results, and suggest modifications of strategies already defined, which are then evaluated by Monte Carlo methods. Finally, variants on Tree Solitaire are suggested, their general implications are discussed, and using the methods already developed one of the most suggestive variants is studied and the results show a significant reversal from those of the original game, which is explained by the difference in the games on one particular.
42. Growth and fruit development of mangosteen (Garcinia mangostana L.) in related with plant nutrients during phenological development
• date - 2005
• creator - Pechkeo, S.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27_openweek_suppl3_pdf/10_mangosteen.pdf
• description - The imbalance or deficiency of essential nutrients in soils and plant may cause poor fruit quality of mangosteen fruit; translucent flesh disorder (TFD) and internal gumming fruits. Therefore, an investigation of nutrient changes in soils and plant (root, branch, leaf and fruit) of mangosteen (Garcinia mangostana L.) during phenological development is a useful guideline for fertilizer management. This research aimed to investigate the pattern of plant nutrients accumulation and nutrient requirement during phenological development of the mangosteen trees. Soil sampling was taken at 4 depths; 0-15, 15-30, 30-50 and 50-100 cm, from soil surface around the middle of the tree canopy and analyzed for some important chemical and physical properties. Roots, branches, leaves and fruits from mangosteen trees at 4 periods of growth; preflowering, flowering, fruit development (from bloom to 7th week) and harvesting were sampled, and analyzed related to the changes of soil nutrients. The results indicated that the soil texture varied from sandy clay loam to clay loam (Ruso soil series (Ro); Typic Pelehumults). In addition, the natural soils in mangosteen orchards was strong acid to very strong acid (pH 4.62-4.93, soil:water = 1:5). Mangosteen trees might take high amounts of nutrients from the surface soils (0-15 cm) as follows: N, K, Mg and S for growth in the preflowering period; N, K, S and B in the flowering period; K, Ca and Mg in the 1st half of fruit development period (bloom to 7th week of fruit development) and P in the 2nd half of fruit development period (7th week of fruit development to harvest) compared to other growth periods. The results also showed that in the root, branch and leaf, mangosteen trees required higher amounts of Ca for growth in the preflowering period; K, Mg and S in the flowering period; N in the 1st half of fruit development period and K, Mg and B in the 2nd half of fruit development period compared to other growth periods. In the fruit, N, K, Ca and B contents in the peel of normal fruit were higher than those of TFD fruit, whereas K, Ca, S and B contents in the flesh of normal fruit were higher than those of TFD fruit.
43. The Big Thaw
• date -
• creator - Horgan
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=3450D653-FD49-4319-B5FD-8491E64052D&ARTICLEID_CHAR=B79F3FA8-8F0D-4FBC-9FAF-C088963F46B
• description - The vast shield of ice capping the Antarctic is the largest body of freshwater on the planet. If it melted, sea levels would surge by 60 meters, submerging coastal areas around the world. Some scientists have therefore become increasingly alarmed in recent years as David M. Harwood of the University of Nebraska and others have presented evidence that a mere three million years ago, during the Pliocene epoch, the Antarctic ice sheet melted, transforming the frozen continent into a collection of tree-covered islands. The disturbing implication is that global warming, which may push temperatures to Pliocene levels by the middle of the next century, might trigger a catastrophic meltdown of the ice sheet.Now a group led by David E. Sugden of the University of Edinburgh has challenged this scenario. Sugden and his six co-workers report in Nature that they have discovered ice at least eight million years old in a region that, in Harwood's view, should have been clear of ice as recently as three million years ago. The Copyright 1995 Scientific American, Inc. new finding has intensified what was already a fierce debate between "stabilists " and "dynamists" over the ice cap's past and, more important, its future. The Harwood group based its claim of a big thaw on fossilized beech trees and marine diatoms found high in the Transantarctic Mountains, a rocky spine that cuts the Antarctic roughly in half. The beech fossils were undatable, but the diatoms were of a type known to have existed in the southern oceans three million years ago. According to Harwood, the beech trees grew on the ice-free shores of Antarctic islands during the warm Pliocene, and the diatoms thrived in the marine basins surrounding the landmasses. When the balmy weather of the Pliocene gave way to a more frigid climate, the beech trees all died off; the expanding sea ice pushed sediments laden with diatoms up over the islands, where the diatoms mingled with the beech fossils. Those Pliocene islands became the peaks of the Transantarctic Mountains. But George H. Denton of the University of Maine, a member of Sugden's group, questions Harwood's analysis. Denton says that even today diatoms can be blown from the open sea surrounding the Antarctic far inland. The three-million-year-old diatoms found by Harwood might also have been transported from open sea into the Transantarctic Mountains, mingling with the much older fossilized beech trees, Denton explains.
44. Impacts of Livestock Grazing and Tree Clearing on Birds of Woodland and Riparian Habitats
• date - 2007-04
• creator - MARTIN, TARA G.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.2006.00624.x
45. Do browsing elephants damage female trees more?
• date - 2007-03
• creator - Hemborg, Åsa M.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2028.2006.00666.x
• description - Abstract Herbivory in unisexual plants has mainly been assessed in studies of invertebrates, mostly insects. At a different scale of disturbance, browsing by large animals has rarely been studied. Elephants can seriously damage or kill trees by removing parts of the canopy, debark, or break the stem. We compared browsing by African elephants (Loxodonta africana) in male and female Marula trees (Sclerocarya birrea ssp. caffra). We expected females to incur more damage because of their sweet and fleshy fruits, known to attract elephants from far. Following this, we expected females to give more resistance through a denser branch wood that would break off at a larger diameter than in males. We tested this by pulling branches down to simulate elephant browsing as to compare branch resistance and design. All trees showed signs of browsing and females were generally more injured. However, there was no sexual difference in wood density and diameter at breaking point. Female branches were shorter, less ramified and carried fewer reproductive shoots than male branches. This sexual dimorphism could result from costly reproductive allocation in females and sexual selection, promoting intensive male flowering. Indirectly, elephants could reinforce this difference by engaging females more in tissue repair after browsing.
46. Coherence in natural language : data structures and applications
• date - 2005-09-27T18:42:33Z
• creator - Wolf, Florian, 1975-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/28854
• description - Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, February 2005.
47. Voyages: Trees of the Triassic
• date -
• creator - Marguerite Holloway
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=7A32B6BE-71CF-4E92-8233-6E6C4F483C7&ARTICLEID_CHAR=95784FCC-6A91-4F81-A258-38BFADEF901
• description - The land and its trees are yellow, pink, putty, purple, periwinkle, orange, gray, lichen green and the green of young grass. White, too, if there is a sprinkling of snow. And the colors, those of the land at least, are always changing-flat in midday, deep and glowing at sunrise and sunset. But the trees are unchanging, stranded on mesas or hillsides or washes, broken and beautiful, made of stone.The Painted Desert is part of Petrified Forest National Park in Arizona, and both are part of a landscape that today is sere and denuded but that 225 to 220 million years ago was lush and swampy, thick with towering conifers and busy with crocodilelike creatures and small dinosaurs. When the trees fell, they were buried under mud, and over millions of years silica from volcanic ash percolated through the water and covered and then hardened them.
48. Effects of crop load on yield and fruit quality of mangosteen
• date - 2005
• creator - Phonrong, K.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27_openweek_suppl3_pdf/09_mangosteen.pdf
• description - To assess crop load effect on yield and quality of mangosteen fruits, an experiment was established in a farmer’s orchard at Tambol Koh Hong, Hat Yai, Songkhla. The experiment was arranged as a completely randomized design with 4 treatments: 1) <500 fruit pt-1 2) 501-1000 fruit pt-1 3) 1001-1500 fruit pt-1 and 4) >1500 fruit pt-1 with 6 replicates. Twenty-four 14-year mangosteen trees were used. It was found that the mangosteen trees in the treatment of 1001-1500 fruit pt-1 provided a significantly high yield (84.23 kg pt-1) with a high percentage (66%) of standard fruit size (>70 g.), while the mangosteen trees in the treatment of <500 fruit pt-1 gave the lowest yield. Although the significantly highest yield (119.89 kg pt-1) was found in the treatment of >1500 fruit pt-1, most of the fruits were of small size. It was remarkable that the mangosteen trees in the treatment of >1500 fruit pt-1 exhibited high physiological response with high stomatal conductance and water uptake. After harvesting, leaf flushing and root growth of the plants in the treatment of >1500 fruit pt-1 were poor. This would lead to an occurrence of alternate- bearing in the consecutive year.
49. 3.A24 Freshman Seminar: The Engineering of Trees, Spring 2003
• date - 2007-03-14T05:40:35Z
• creator - Gibson, Lorna J.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36825
• description - Why are things in nature shaped the way they are? Why can't trees grow taller than they are? Why is grass skinny and hollow? Why are some leaves full of holes? These are the types of questions Dr. Lorna Gibson's freshman seminar at MIT has been investigating. We invite you to explore with us. Questions such as these are the subject of biomimetic research. When engineers copy the shapes found in nature we call it Biomimetics. the word biomimic comes from bio, as in biology and mimetic, which means to copy. Join us as we explore and look for answers to why similar shapes occur in so many natural things and how physics change the shape of nature.
50. Bushmeat and the Fate of Trees with Seeds Dispersed by Large Primates in a Lowland Rain Forest in Western Amazonia
• date - 2007-05
• creator - Nuñez-Iturri, Gabriela
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00276.x
• description - ABSTRACT In Neotropical forests, large fruit-eating primates play important ecological roles as dispersal agents of large seeds. Bushmeat hunting threatens to disrupt populations of primates and large-seeded trees. We test the hypothesis that otherwise intact Neotropical forests with depressed populations of large primates experience decline in recruitment of large-seeded trees. We quantify the proportion of small juveniles (> 0.5 m tall–1 cm diameter at breast height, DBH) of large primate-dispersed tree species found underneath heterospecifc trees that are also dispersed by large primates at two protected sites in Manu National Park and one hunted site outside Manu N.P. in southeastern Peru. The forests are comparable in edaphic and climatic qualities, successional stage, and adult tree species composition. We found that hunting locally exterminates populations of large primates, and reduced primates of intermediate body size (hereafter “medium primates”) by 80 percent. Moreover, tree species richness was 55 percent lower and density of species dispersed by large and medium-bodied primates 60 percent lower in hunted than in protected sites. In addition, richness and density of abiotically dispersed species and plants dispersed by non-game animals are greater in hunted sites. Overhunting threatens to disrupt the ecological interactions between primates and the plants that rely on them for seed dispersal and recruitment. Sustainable wildlife management plans are urgently needed, because protected areas are at risk of becoming “island” parks if buffer zones become empty of animals and have impoverished flora.
51. Range expansion due to urbanization: Increased food resources attract Grey-headed Flying-foxes (Pteropus poliocephalus) to Melbourne
• date - 2006-04
• creator - WILLIAMS, NICHOLAS S. G.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01590.x
• description - Abstract  Urbanization profoundly alters the biota of areas that become cities and towns. Many species are introduced by humans while indigenous species often decline. Although these changes are well known, the long-term ecological effects of new species and their interactions are seldom considered and rarely documented. This study examines changes in diversity and temporal availability of the food resources of Pteropus poliocephalus (Grey-headed Flying-fox) in the Melbourne region using a variety of historical and current data sources. Our results indicate that urbanization has influenced the distribution, abundance and ecology of P. poliocephalus through a dramatic increase in the quantity and temporal availability of food resources. Prior to European settlement, only 13 species recorded in the range-wide diet of P. poliocephalus grew in the Melbourne area. Compilations of street-tree databases indicate that an additional 87 species have been planted on Melbourne’s streets and that there are at least 315 500 trees that are able to provide food for P. poliocephalus. Phenology records indicate that street trees have lengthened the temporal availability of food for P. poliocephalus. A period of natural food scarcity between May and August has been ameliorated by street trees which have provided nectar and a previously absent fruit resource. These changes are likely to be a major factor contributing to the recent range expansion of P. poliocephalus and the establishment of a permanent camp in Melbourne.
52. Beautifying the home with trees, shrubbery and lawns [electronic resource]
• date - [1941]
• creator -
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/uf00002889.pdf
• description - Electronic reproduction. [Florida] : Florida State Board of Education, Division of Colleges and Universities, PALMM Project, 2002. Mode of Access : World Wide. System Requirements: Internet connectivity; Web browser softwar e; Adobe Acrobat Reader to view and print PDF files. Electronically reproduced from Collection in George A. Smathers Libraries at the University of Florida.
53. Dendrimer Molecules
• date -
• creator - Tomalia
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=A12504E9-7B46-43F0-894A-8025E9E95FB&ARTICLEID_CHAR=C6A066E6-132C-4F5E-9610-31EF6434D22
• description - In the center of Michigan, along the Chippewa River, some 130 miles southeast of Sleeping Bear Dunes National Lakeshore, the land is not productive enough for traditional agriculture, but it is adequate for growing trees. Thousands of trees of all types, with every branching pattern and shape imaginable, flourish there. Year after year young seedlings with single trunks emerge. Then their trunks elaborate branches, and those branches produce more branches in the same way, giving rise to the lush and varied forest.As I pondered these trees near my home some 20 years ago with the eyes of a chemist, the systems of branches made me wonder whether one could design large, precisely defined molecules by adding branch after branch onto some original substance. The idea of gaining such control over the formation of a molecule appealed to me immediately on both theoretical and practical grounds, but it was not until the end of the 1970s that I found a way to put the concept into practice. Today my technique and other similar approaches are making it possible to construct treelike molecules that mimic a variety of biological structures, including proteins. There is good reason to believe that these synthetic constructions will prove valuable in medicine, the electronics industry and other fields.
54. Journey to Forever: Appropriate Technology
• date - 2006-12
• creator - Journey to Forever Keith Addison
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=58FA9353-55A4-4AFC-A73A-69ABCBAFCEFD
• description - Journey to Forever is a pioneering expedition by a small, mobile NGO (Non-Government Organization) involved in environment and rural development work, starting from Hong Kong and travelling 40,000 kilometres through 26 countries in Asia and Africa to Cape Town, South Africa. The "route" they follows takes the user from the cities and populated districts to remote and inaccessible areas (usually also the least developed and poorest areas), where we'll be studying and reporting on environmental conditions and working for local NGOs on rural development projects in local communities. The focus is on trees, soil and water, sustainable farming, sustainable technology, and family nutrition. The aim is to help people fight poverty and hunger, and to help sustain the environment we all must share. Projects inlcude those in community development, rural development, city farms, organic gardening, composting, small farms, biofuels, solar box cookers, trees, soil, water, seeds, vehicles, appropirate technology. Schools projects include: Biofuels, Solar box cookers, Backpack stove, PicoTurbine, Low-tech radio, What to do with a cardboard carton, Sisters of silk, Silkworms in a shoebox, School gardens, School composting, Trees and forests, The Beach House fish pond, HOMeR, Eco-footprint School and youth programs on the Web, Education resources on the Web, Children's poetry. Translated into English, Japanese, Chinese and Spanish.
55. Benefits of Trees
56. Estimating evapotranspiration from the Amazon Basin using the atmospheric water balance
• date - 2006-12-18T20:37:10Z
• creator - Karam, Hanan Nadim
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/35086
• description - by Hanan Nadim Karam.
57. Lessons from the Wolf
• date -
• creator - Jim Robbins
• provider - NSDL OAI Repository
• description - Several scrawny cottonwood trees do not usually generate much excitement in the world of ecology. But on a wind-whipped August afternoon in Yellowstone National Park's Lamar Valley, William J. Ripple, a professor of botany at Oregon State University, stands next to a 12-foot-high cottonwood tree and is quietly ecstatic. "You can see the terminal bud scars," the bespectacled Ripple says, bending the limber tree over to show lines that mark a year's growth of a foot or more on the broom-handle-size trunk. "You can see that elk haven't browsed it this year, didn't browse it last year and, in fact, haven't browsed it since 1998.Ripple gestures at the sprawling mountain valley around us and points out that although numerous other cottonwoods dot the landscape, this knot of saplings comprises the only young ones - the rest of this part of the Lamar is a geriatric ward for trees. The stately specimens that grow in the valley bottom are 70 to 100 years old, and not a newcomer is in sight to take their place. On the hillside, aspen trees present a similar picture. Groves of elderly aspen tremble in the wind, but no sprouts push up in the understory.
58. Stochastic processes on graphs with cycles : geometric and variational approaches
• date - 2005-08-23T19:35:25Z
• creator - Wainwright, Martin J. (Martin James), 1973-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/8371
• description - Stochastic processes defined on graphs arise in a tremendous variety of fields, including statistical physics, signal processing, computer vision, artificial intelligence, and information theory. The formalism of graphical models provides a useful language with which to formulate fundamental problems common to all of these fields, including estimation, model fitting, and sampling. For graphs without cycles, known as trees, all of these problems are relatively well-understood, and can be solved efficiently with algorithms whose complexity scales in a tractable manner with problem size. In contrast, these same problems present considerable challenges in general graphs with cycles. The focus of this thesis is the development and analysis of methods, both exact and approximate, for problems on graphs with cycles. Our contributions are in developing and analyzing techniques for estimation, as well as methods for computing upper and lower bounds on quantities of interest (e.g., marginal probabilities; partition functions). In order to do so, we make use of exponential representations of distributions, as well as insight from the associated information geometry and Legendre duality. Our results demonstrate the power of exponential representations for graphical models, as well as the utility of studying collections of modified problems defined on trees embedded within the original graph with cycles. The specific contributions of this thesis include the following. We develop a method for performing exact estimation of Gaussian processes on graphs with cycles by solving a sequence of modified problems on embedded spanning trees.
59. Effect of canopy manipulation on growth and yield of mangosteen
• date - 2007
• creator - Hadloh, P.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/29-3_online/0125-3395-29-3-0615-0625.pdf
• description - A pruning trial was established to investigate the effect of canopy manipulation on growth and yield of mangosteen under field conditions at The-Pha research station, Songkhla province. Forty 7-year-oldmangosteen trees were used and the study designed as randomized complete blocks with 4 treatments in 10 replicates. The treatments were as follows: 1. control or no-pruning (T1), 2. cutting upper one along one sideof each tier of branches along the main stem (T2), 3. cutting one tier of branches with the upper tier along the main stem remaining (T3) and 4. top-cutting at 3-meter plant height (T4). It was found that 1 year afterpruning, the trees in T2 exhibited highest relative plant height and longest branch length after pruning (6.63m /4 month and 35.31 cm /4 month, respectively). First-year bearing was found only in T1 and T4, and the fruit yields in T1 and T4 were (3.13 and 2.31 kg/tree, respectively). It was remarkable that light transmissionthrough plant canopy in T4 gave the highest photosynthetically active radiation PAR (48.55%), but T1 the lowest PAR (2.46%). Thus, the plant growth in T4 was greater than in T1, and the mangosteen trees in T4also exhibited high root proliferation. From the result, it is suggested that canopy manipulation of T4 is anappropriate method.
60. Hunting of Mammals Reduces Seed Removal and Dispersal of the Afrotropical Tree Antrocaryon klaineanum (Anacardiaceae)
• date - 2007-05
• creator - Wang, Benjamin C.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00275.x
• description - ABSTRACT Throughout the tropics, mammalian seed dispersers are being driven to local extinction by intense hunting pressure, generating concern not only about the loss of these species, but also about the consequences for the plants they disperse. We compared two rain forest sites in Cameroon—one with heavy hunting pressure and one protected from hunting—to appraise the loss of mammalian seed dispersers and to assess the impact of this loss on seed removal and seed dispersal of Antrocaryon klaineanum (Anacardiaceae), a mammal-dispersed tree. Surveys of arboreal frugivores indicate that three of the five monkey species, as well as chimpanzee and gorilla, have been extirpated from the hunted forest. Diaspore counts underneath A. klaineanum adults (six trees per site) indicate that seed removal is severely reduced in the hunted forest. Finally, genetic maternity exclusion analysis (using 3–7 nuclear microsatellite loci) of maternally inherited endocarp tissue from diaspores collected under the canopies of 12 fruiting “mother” trees (six trees per site) revealed that seed dispersal in the hunted forest is also greatly reduced. In the hunted forest with reduced mammal dispersal agents, only 1 of the 53 assayed endocarps (2%) did not match the mother and was determined to be from a dispersed diaspore. By contrast, in the protected forest, 20 of the 48 assayed endocarps (42%) were from dispersed diaspores. This study provides strong evidence that loss of dispersal agents can lead to reduced seed removal and loss of seed dispersal, disrupting the seed dispersal cycle.
61. Establishment of Broad-leaved Thickets in Serengeti, Tanzania: The Influence of Fire, Browsers, Grass Competition, and Elephants 1
• date - 2006-09
• creator - Sharam, Gregory
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2006.00195.x
• description - ABSTRACT The role of Euclea divinorum in the establishment of broad-leaved thickets was investigated in Serengeti National Park, Tanzania. Thickets are declining due to frequent fires, but have not reestablished when fires have been removed. Seedlings of E. divinorum, a fire-resistant tree, were found in grassland adjacent to thickets and as thicket canopy trees and may function to facilitate thicket establishment. Seedlings of thicket species were abundant under E. divinorum canopy trees but not in the grassland, indicating that E. divinorum can facilitate forest establishment. We examined E. divinorum establishment in grassland by measuring survival and growth of seedlings with respect to fire, browsers, elephants, and competition with grass. Seedling survival was reduced by fire (50%), browsers (70%), and competition with grass (50%), but not by elephants. Seedling growth rate was negative unless both fire and browsers, or grass was removed. Establishment of thickets via E. divinorum is not occurring under the current conditions in Serengeti of frequent fires, abundant browsers, and dense grass in riparian areas. Conditions that allowed establishment may have occurred in 1890–1920s during a rinderpest epizootic, and measurements of thicket canopy trees suggest they established at that time.
62. The Use of French Spikes to Collect Botanical Vouchers in Permanent Plots: Evaluation of Potential Impacts 1
• date - 2006-07
• creator - Magnusson, William E.
• provider - NSDL OAI Repository
• location - Biotropica 38(4), 555-557.
• description - RESUMO Avaliamos os impactos do uso de garras para escalada em árvores no crescimento e na sobrevivência destas, durante um intervalo de 14-28 meses. Nenhuma árvore escalada com garras morreu no intervalo de estudo e a taxa de crescimento de árvores escaladas com garras não diferiu da taxa de árvores não escaladas. Recomendamos o registro de todas as árvores escaladas com garras, principalmente em parcelas permanentes.
63. Effects of green tree retention, prescribed burning and soil treatment on pine weevil (Hylobius abietis and Hylobius pinastri) damage to planted Scots pine seedlings
• date - 2006-01
• creator - Pitkänen, A.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1461-9563.2006.00276.x
• description - Abstract 1 Feeding damage and mortality caused to planted Scots pine seedlings by the pine weevils Hylobius abietis and Hylobius pinastri were studied on burned and unburned sites with 0, 10 and 50 m3 per hectare levels of green tree retention from the second to the fourth summer after logging and burning of the sites. 2 The rate of severe feeding damage to pine seedlings caused by pine weevils was higher on burned clearcut sites than on unburned ones, whereas burning did not increase the feeding damage rate on sites with groups of retention trees. The damage rate in the fourth summer was approximately the same on burned and unburned sites. 3 Pine weevil feeding was the major cause of mortality of freshly planted pine seedlings on unburned sites. On burned sites, mortality was higher than the rate of severe feeding damage, particularly in the second summer after burning, possibly owing to fungal attack and abiotic factors. 4 At a retention tree level of 50 m3, feeding damage to the seedlings was lower than on clearcuts and at a 10 m3 retention tree level. Furthermore, on sites with 50 m3 of retention trees, scarification of the soil was found to decrease feeding damage more effectively than on clearcuts and 10 m3 sites. If the seedlings were situated in the centre of scarified patches, scarification alone was as effective as insecticide treatment on unscarified soil for decreasing feeding damage and mortality. 5 The results suggest that when burning is applied as silvicultural treatment after clear-cuts, retention of trees is recommended to reduce the damages caused by pine weevils on pine seedlings.
64. Changes in the stand structure (1975–2000) of coastal Banksia forest in the long absence of fire
• date - 2007-05
• creator - GENT, MARTY L.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01667.x
• description - Abstract  Revisitation studies enable long-term changes in vegetation to be deciphered and insights into plant community succession to be gained. This is particularly important when assessing the effects of fire exclusion in ecosystems where fire is thought to have once been common. Using two adjacent coastal Banksia integrifolia forest stands in southern Victoria, Australia initially surveyed in 1975 by Hazard and Parsons, we document the changes that occurred in the stand structure between 1975 and 2000. Western Park (WP) has now remained unburnt for over 100 years while Cerberus Naval Base (CNB) was most recently burnt in 1942. Banksia integrifolia densities have decreased at both sites over the 25-years period by an average of 42–77%, as have other coastal native shrubs (e.g. Leptospermum laevigatum, Leucopogon parviflorus). Trees at WP appear to have died due to old age while mortality at CNB is presumed to be due to stand thinning in response to intense competition for light. Successful recruitment by Banksia has been minimal; trees less than 9 cm girth over bark at breast height (GBBH) were absent at CNB while no trees <19 cm GBBH were observed at WP. The long-term absence of disturbance such as fire is suspected to be one of the causes of regeneration failure of the stand at WP. Gap phase regeneration is not apparent in B. integrifolia and hence, long-term succession to a more grassy community is likely when fire is excluded for long periods.
65. Network Flow Models for Designing Diameter-Constrained Minimum Spanning and Steiner Trees
• date - 2004-05-28T19:33:01Z
• creator - Gouveia, Luis
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5310
• description - The Diameter-Constrained Minimum Spanning Tree Problem seeks a least cost spanning tree subject to a (diameter) bound imposed on the number of edges in the tree between any node pair. A traditional multicommodity flow model with a commodity for every pair of nodes was unable to solve a 20-node and 100-edge problem after one week of computation. We formulate the problem as a directed tree from a selected central node or a selected central edge. Our model simultaneously finds a central node or a central edge and uses it as the source for the commodities in a directed multicommodity flow model with hop constraints. The new model has been able to solve the 20-node, 100-edge instance to optimality after less than four seconds. We also present model enhancements when the diameter bound is odd (these situations are more difficult). We show that the linear programming relaxation of the best formulations discussed in this paper always give an optimal integer solution for two special, polynomially-solvable cases of the problem. We also examine the Diameter Constrained Minimum Steiner Tree problem. We present computational experience in solving problem instances with up to 100 nodes and 1000 edges. The largest model contains more than 250,000 integer variables and more than 125,000 constraints.
66. Design of LISP-based Processors, or SCHEME: A Dielectric LISP, or Finite Memories Considered Harmful, or LAMBDA: The Ultimate Opcoed
• date - 2004-10-01T20:33:03Z
• creator - Steele, Guy Lewis, Jr.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5731
• description - We present a design for a class of computers whose 'instruction sets' are based on LISP. LISP, like traditional stored-program machine languages and unlike most high-level languages, conceptually stores programs and data in the same way and explicitly allows programs to be manipulated as data. LISP is therefore a suitable language around which to design a stored-program computer architecture. LISP differs from traditional machine languages in that the program/data storage is conceptually an unordered set of linked record structures of various sizes, rather than an ordered, indexable vector of integers or bit fields of fixed size. The record structures can be organized into trees or graphs. An instruction set can be designed for programs expressed as such trees. A processor can interpret these trees in a recursive fashion, and provide automatic storage management for the record structures. We describe here the basic ideas behind the architecture, and for concreteness give a specific instruction set (on which variations are certainly possible). We also discuss the similarities and differences between these ideas and those of traditional architectures. A prototype VLSI microprocessor has been designed and fabricated for testing. It is a small-scale version of the ideas presented here, containing a sufficiently complete instruction interpreter to execute small programs, and a rudimentary storage allocator. We intend to design and fabricate a full-scale VLSI version of this architecture in 1979.
67. Carbon Sequestration of Trees in City of Kitchener Parks
68. Photographs depicting Big Cypress Swamp and cypress trees, 1928?-1931? [electronic resource]
• date - 1928-1931
• creator - Matlack, Claude Carson, 1878-1944.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTCM00500019.pdf
• description - Electronic format produced as part of Reclaiming the Everglades, a collaborative project of the University of Miami, Florida International University, and the Historical Museum of Southern Florida, funded by the Library of Congress/Ameritech National Digital Library Program.
69. Probability theory on Galton-Watson trees
70. Heuristics, LPs, and Generalizations of Trees on Trees
• date - 2004-05-28T19:36:32Z
• creator - Balakrishnan, Anantaram
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5377
• description - We study a class of models, known as overlay optimization problems, with a "base" subproblem and an "overlay" subproblem, linked by the requirement that the overlay solution be contained in the base solution. In some telecommunication settings, a feasible base solution is a spanning tree and the overlay solution is an embedded Steiner tree (or an embedded path). For the general overlay optimization problem, we describe a heuristic solution procedure that selects the better of two feasible solutions obtained by independently solving the base and overlay subproblems, and establish worst-case performance guarantees on both this heuristic and a linear programming relaxation of the model. These guarantees depend upon worst-case bounds for the heuristics and linear programming relaxations of the unlinked base and overlay problems. Under certain assumptions about the cost structure and the optimality of the subproblem solutions, the performance guarantees for both the heuristic and linear programming relaxation of the combined overlay optimization model are 33%. We also develop heuristic and linear programming performance guarantees for specialized models, including a dual path connectivity model with a worst-case performance guarantee of 25%, and an uncapacitated multicommodity network design model with a worst-case performance guarantee (approximately) proportional to the square root of the number of commodities.
71. A Polyhedral Intersection Theorem for Capacitated Spanning Trees
• date - 2004-05-28T19:36:09Z
• creator - Hall, Leslie A.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5370
• description - In a two-capacitated spanning tree of a complete graph with a distinguished root vertex v, every component of the induced subgraph on V\{v} has at most two vertices. We give a complete,non-redundant characterization of the polytope defined by the convex hull of the incidence vectors of two-capacitated spanning trees. This polytope is the intersection of the spanning tree polytope on the given graph and the matching polytope on the subgraph induced by removing the root node and its incident edges. This result is one of very few known cases in which the intersection of two integer polyhedra yields another integer polyhedron. We also give a complete polyhedral characterization of a related polytope, the 2-capacitated forest polytope.
72. The Delta Tree: An Object-Centered Approach to Image-Based Rendering
• date - 2004-10-04T14:15:32Z
• creator - Dally, William J.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5936
• description - This paper introduces the delta tree, a data structure that represents an object using a set of reference images. It also describes an algorithm for generating arbitrary re-projections of an object by traversing its delta tree. Delta trees are an efficient representation in terms of both storage and rendering performance. Each node of a delta tree stores an image taken from a point on a sampling sphere that encloses the object. Each image is compressed by discarding pixels that can be reconstructed by warping its ancestor's images to the node's viewpoint. The partial image stored at each node is divided into blocks and represented in the frequency domain. The rendering process generates an image at an arbitrary viewpoint by traversing the delta tree from a root node to one or more of its leaves. A subdivision algorithm selects only the required blocks from the nodes along the path. For each block, only the frequency components necessary to reconstruct the final image at an appropriate sampling density are used. This frequency selection mechanism handles both antialiasing and level-of-detail within a single framework. A complex scene is initially rendered by compositing images generated by traversing the delta trees of its components. Once the reference views of a scene are rendered once in this manner, the entire scene can be reprojected to an arbitrary viewpoint by traversing its own delta tree. Our approach is limited to generating views of an object from outside the object's convex hull. In practice we work around this problem by subdividing objects to render views from within the convex hull.
73. Construction of Decision Trees
• date - 2004-10-01T20:49:22Z
• creator - Banks, Edwin Roger
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5845
• description - The construction of optimal decision trees for the problem stated within can be accomplished by an exhaustive enumeration. This paper discusses two approaches. The section on heuristic methods gives mostly negative results (E.G. there is no merit factor that will always yield the optimal tests, etc.), but most to these methods do give good results. The section entitled "Exhaustive Enumeration Revisited" indicates some powerful shortcuts that can be applied to an exhaustive enumeration, extending the range of this method.
74. Expert panel assessment of attributes for natural variability benchmarks for biodiversity
• date - 2007-06
• creator - OLIVER, IAN
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01718.x
• description - Abstract  The aim of this study was to identify a practical and defensible set of ecosystem attributes to form the basis of natural variability benchmarks for natural resource managers needing to determine the status of patch-scale species-level biodiversity within woodland and forest ecosystems. We used a form of multicriteria analysis (the analytic hierarchy process, AHP) to record and analyse the knowledge and opinions of 31 Australian ecologists on those ecosystem attributes considered most important as biodiversity surrogates, and those that were considered most feasible to assess. From a pool of 13 landscape context attributes and 62 vegetation condition attributes, practical and defensible attribute sets were identified based on AHP importance and feasibility weights and associated statistical analyses. Experts considered that, on average, landscape context attributes should contribute approximately one-third (0.36) to an assessment of within-vegetation-type species-level biodiversity status, and vegetation condition attributes should contribute the remaining two-thirds (0.64). Our analyses did, however, find a correlation between these importance weights and the spatial scales at which experts worked. The landscape context attributes: patch size, distance to nearest large patch, and connectivity were considered significantly more important than other attributes; however, connectivity received a significantly lower feasibility weight. A minimum set of 11 compositional, structural and functional vegetation condition attributes were identified: richness of native trees; cover of native trees, shrubs and perennial grasses; cover of exotic shrubs, perennial grasses, legumes and forbs; cover of organic litter; recruitment of native tree/shrub saplings; native tree health; and evidence of grazing. We compare our minimum sets of attributes with other published sets, and briefly discuss the issues surrounding the incorporation of attributes into natural variability benchmarks from which indices of terrestrial species-level biodiversity status of woodland and forest patches can be determined.
75. ON TREES AND LOGS
• date - 2003-01-27T21:12:56Z
• creator - Cass, David
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/1809
• description - In this paper we critically examine the main workhorse model in asset pricing theory, the Lucas (1978) tree model (LT-Model), extended to include heterogeneous agents and multiple goods, and contrast it to the benchmark model in financial equilibrium theory, the real assets model (RA-Model). Households in the LT-Model trade goods together with claims to Lucas trees (exogenous stochastic dividend streams specified in terms of a particular good) and long-lived, zero-net-supply real bonds, and are endowed with share portfolios. The RA-Model is quite similar to the LT-Model except that the only claims traded there are zero-net-supply assets paying out in terms of commodity bundles (real assets) and households' endowments are in terms of commodity bundles as well. At the outset, one would expect the two models to deliver similar implications since the LT-Model can be transformed into a special case of the RA-Model. We demonstrate that this is simply not correct: results obtained in the context of the LT-Model can be strikingly different from those in the RA-Model. Indeed, specializing households' preferences to be additively separable (over time) as well as log-linear, we show that for a large set of initial portfolios the LT-Model -- even with potentially complete financial markets -- admits a peculiar financial equilibrium (PFE) in which there is no trade on the bond market after the initial period, while the stock market is completely degenerate, in the sense that all stocks offer exactly the same investment opportunity -- and yet, allocation is Pareto optimal. We then thoroughly investigate why the LT-Model is so much at variance with the RA-Model, and also completely characterize the properties of the set of PFE, which turn out to be the only kind of equilibria occurring in this model. We also find that when a PFE exists, either (i) it is unique, or (ii) there is a continuum of equilibria: in fact, every Pareto optimal allocation is supported as a PFE. Finally, we show that most of our results continue to hold true in the presence of various types of restrictions on transactions in financial markets. Portfolio constraints however may give rise other types of equilibria, in addition to PFE. While our analysis is carried out in the framework of the traditional two-period Arrow-Debreu-McKenzie pure exchange model with uncertainty (encompassing, in particular, many types of contingent commodities), we show that most of our results hold for the analogous contin
76. White pine weevil performances in relation to budburst phenology and traumatic resin duct formation in Norway spruce
• date - 2006-05
• creator - Poulin, Julie
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1461-9563.2006.00293.x
• description - Abstract 1 As the phenological window hypothesis was reported to be significant in influencing the fitness of many herbivores feeding on tree foliage, could it also explain the performance of an insect such as the white pine weevil Pissodes strobi mainly attacking the bark phloem of conifers? 2 Under field conditions, adult weevils were caged on Norway spruce trees presenting a natural variation in their shoot growth phenology. 3 We evaluated white pine weevil biological performances, including oviposition, the number of emerged insects, survival, adult mean weight and tree defense responses as reflected by the production of induced resin canals. 4 None of the white pine weevil biological parameters was significantly affected by Norway spruce phenology. 5 The number of eggs per hole, the number of oviposition holes per leader, the number of emerged adults and their mean weight were not affected by host phenology. 6 The intensity of the traumatic response observed was variable and not correlated with budburst phenology. 7 Trees with higher traumatic responses, forming two or more layers of traumatic ducts, had lower adult emergence and estimated survival. 8 The distance between the first layer of traumatic resin ducts and the start of the annual ring was not correlated with the number of emerged weevils. 9 Norway spruce, which is an exotic tree in North America and a relatively recent host for the white pine weevil, might not possess the defense mechanisms necessary to fight off the white pine weevil.
77. Developing fundamentally based models for autoignition
• date - 2006-03-29T18:34:26Z
• creator - Wijaya, Catherina D. (Catherina Dewi)
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/32326
• description - by Catherina D. Wijaya.
78. Introduction of giraffe changes acacia distribution in a South African savanna
• date - 2001-09
• creator - Bond, William J.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1046/j.1365-2028.2001.00319.x
• description - Abstract Large mammal herbivores can have significant effects on the structure and composition of plant communities. We studied the impacts of an introduced giraffe population on Acacia species at Ithala Game Reserve in South Africa. Browse intensity and Acacia mortality were assessed in field transects, and in road transects covering the reserve road network. Several Acacia species occurring in high-density giraffe areas had high levels of mortality. Populations of Acacia davyi were extinct in areas accessible to giraffe. Most A. caffra trees within giraffe browse height were dead and A. karroo, the most common species, was also heavily affected. Some species, including A. tortilis, showed no or very low mortality attributable to giraffe browsing. Healthy populations of sensitive species occurred in areas within, and adjacent to, the reserve in areas with low or no giraffe browsing. Areas too steep for giraffe access formed spatial refuges for these trees. The differential mortality that is occurring as a consequence of giraffe browsing is altering species composition and species distribution in this savanna landscape.
79. Diversity of vascular plants on Ssese islands in Lake Victoria, central Uganda
• date - 2006-03
• creator - Ssegawa, Paul
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2028.2006.00609.x
• description - Abstract Diversity and distribution of trees [≥5 cm diameter at breast height (dbh)], shrubs and herbs was assessed in thirty 0.05-ha (10 × 50 m) plots of a tropical high forest in the Ssese islands of Lake Victoria, central Uganda. The aim was to determine the floristic richness and composition of the forests. We recorded 179 species belonging to 70 families and 146 genera. Of these, nine families had five species or more. Rubiaceae was the richest with fourteen species followed by Euphorbiaceae (thirteen), Apocynaceae (ten) and Moraceae (nine). The majority of the families (35) were represented by one species each. Fifty-eight herbaceous species, 39 lianas, ten shrubs and 72 species of trees were recorded. The commonest species recorded in the forest included: Uapaca guineensis Mull. Arg., Tabernaemontana pachysiphon Stapf., and Aframomum luteoalbum (K Schum.) K. Schum. Among the rare species encountered were Ficus densistipulata De Willd., Englerophytum oblanceolatum (S. Moore) Pennington, and Afromomum zambeziacum (Bak.) K. Schum. The present study has shown that the Ssese islands are floristically rich in species and compare well with other mainland forests. Species richness, rarity and uniqueness of habitats can be considered as approaches in the prioritization of conservation sites within the fragmented forests of Ssese islands.
80. Cache-oblivious dynamic search trees
• date - 2005-09-26T20:20:04Z
• creator - Kasheff, Zardosht, 1981-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/28417
• description - Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.
81. Will tree euphorbias (Euphorbia tetragona and Euphorbia triangularis ) survive under the impact of black rhinoceros (Bicornis diceros minor) browsing in the Great Fish River Reserve, South Africa?
• date - 2006-03
• creator - Heilmann, Linda C.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2028.2006.00620.x
• description - Abstract The impact of black rhinoceros (Bicornis diceros minor) on the tree euphorbias Euphorbia tetragona and Euphorbia triangularis was studied in the Great Fish River Reserve, South Africa. Black rhinoceros pushed over about 5–7% of the trees in a 2-month period. There was a preference of rhinos for smaller trees, however this preference did not guarantee euphorbia survival in the larger size classes. This means that tree euphorbias could very well disappear from all areas accessible to rhinos. Rhino feeding choices were correlated with higher plant moisture content, higher nitrogen content, and a higher digestibility.
82. Tree species population dynamics in a secondary forest at Ile-Ife, Nigeria after a ground fire
• date - 2007-03
• creator - Muoghalu, Joseph Ikeckukwu
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2028.2006.00680.x
• description - Abstract Tree species population dynamics were studied in a 0.25-ha secondary rain forest plot which was accidentally burnt in 1983 by a severe ground fire. The effect of the fire on tree species in the plot was assessed after 14 months in 1984 and 14 years in 1997 to establish the changes in tree species composition and structural characteristics of the plot after the fire. The present study investigated the changes in species composition, mortality, recruitment rates and some structural characteristics of the plot 18 years after the fire. The results from this study were compared with previous studies in the plot. Tree species richness of the plot (37 per 0.25 ha in 1983), which increased to 40 and 71 species 1 and 14 years respectively after the fire dropped to 63 species 18 years after. Fifteen species, which were not originally present before the fire, are established and abundant now. Ten woody species, each of which were originally present and which established 1 year after the fire have died. Stem density increased from 3192 trees ha−1 1 year to 10,064 trees ha−1 18 years after the fire. Basal area increased while species diversity, which increased to 3.41 14 years after, decreased to 3.07 18 years after. The annual mortality rate was 2.1% 14 years after and annual recruitment rates were 74.5% year−1 and 35.7% year−1 1 and 18 years after the fire, respectively. These observations give insight to secondary forest succession after fire.
83. Enumerative and algebraic aspects of matroids and hyperplane arrangements
• date - 2005-10-14T19:39:30Z
• creator - Ardila, Federico, 1977-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/29287
• description - Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2003.
84. Theories, Pre-Theories and Finite State Transformations on Trees
• date - 2004-10-04T14:45:16Z
• creator - Wand, Mitchell
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6190
• description - The closure of an algebra is defined as a generalization of the semigroup of a finite automation. Pretheories are defined as a subclass of the closed algebras, and the relationship between pretheories and the algebraic theories of Lawrence [1963] is explored. Finally, pretheories are applied to the characterization problem of finite state transformations on trees, solving an open problem of Thatcher [1969].
85. Beware of the trees
86. Drip Irrigation
87. Forest Fires and Percolation
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://polymer.bu.edu/java/java/blaze/blaze.html
• description - This is the description and instructions as well as a link for the Forest Fires and Percolation applet. It builds a background with a "hands-on" activity for the students which then leads to the applet itself. The applet is a game where the object is to save as many trees from the forest fire as possible. It shows the spread of a fire with the variable of density and the probabilty of the number of surviving trees.
88. Communism in trees goes underground
• date -
• creator - Science News Online
• provider - NSDL OAI Repository
• location - http://www.sciencenews.org/pages/sn_arc97/8_9_97/fob2.htm
• description - This news article reports that some trees give their neighbors carbon that they have captured from the atmosphere. Scientists discovered that shade enhances a tree's ability to receive and that carbon appears to travel via a subterranean web formed by a common group of fungi. The article concludes with references and sources (with contact information).
89. Comparing Gene Trees and Genome Trees: A Cobweb of Life?
90. The first book of trees
• date - 1951-00-00T00:00:00Z
• creator - Cormack, Maribelle, 1902-
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
91. Getting acquainted with the trees
• date -
• creator - McFarland, J. Horace (John Horace), 1859-1948
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
92. Cooperative multicast in wireless networks
• date - 2006-03-29T18:51:00Z
• creator - Li, Fulu, 1970-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/32507
• description - Wireless communication has fundamental impairments due to multi-path fading, attenuation, reflections, obstructions, and noise. More importantly, it has historically been designed to mimic a physical wire; in concept other communicators in the same region are viewed as crossed wires. Many systems overcome these limitations by either speaking more loudly, or subdividing the space to mimic the effect of a separate wire between each pair. This thesis will construct and test the value of a cooperative system where the routing and transmission are done together by using several of the radios in the space to help, rather than interfere. The novel element is wireless, cooperative multicast that could be the basis for a new broadcast distribution paradigm. In the first part of the thesis,. we investigate efficient ways to construct multicast trees by exploring cooperation among local radio nodes to increase throughput and conserve energy (or battery power), whereby we assume single transmitting node is engaged in a one-to-one or one-to-many transmission. In the second part of the thesis, we further investigate transmit diversity in the general context of cooperative routing, whereby multiple nodes are allowed for cooperative transmissions. Essentially, the techniques presented in the second part of the thesis can be further incorporated in the construction of multicast trees presented in the first part.
93. Shade-trees in towns and cities; their selection, planting, and care as applied to the art of street decoration; their diseases and remedies; their control and supervision
• date - 1911-00-00T00:00:00Z
• creator - Solotaroff, William
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
94. A Constant-Factor Approximation Algorithm for Embedding Unweighted Graphs into Trees
• date - 2004-10-08T20:43:19Z
• creator - Badoiu, Mihai
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6742
• description - We present a constant-factor approximation algorithm for computing an embedding of the shortest path metric of an unweighted graph into a tree, that minimizes the multiplicative distortion.
95. Bayesian Semiparametric Proportional Odds Models
• date - 2007-03
• creator - Hanson, Timothy
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1541-0420.2006.00671.x
• description - Summary.  Methodology for implementing the proportional odds regression model for survival data assuming a mixture of finite Polya trees (MPT) prior on baseline survival is presented. Extensions to frailties and generalized odds rates are discussed. Although all manner of censoring and truncation can be accommodated, we discuss model implementation, regression diagnostics, and model comparison for right-censored data. An advantage of the MPT model is the relative ease with which predictive densities, survival, and hazard curves are generated. Much discussion is devoted to practical implementation of the proposed models, and a novel MCMC algorithm based on an approximating parametric normal model is developed. A modest simulation study comparing the small sample behavior of the MPT model to a rank-based estimator and a real data example is presented.
96. On Trees and Logs
• date - 2002-06-05T20:14:06Z
• creator - Cass, David
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/665
• description - In this paper we critically examine the main workhorse model in asset pricing theory, the Lucas (1978) tree model (LT-Model), extended to include heterogeneous agents and multiple goods, and contrast it to the benchmark model in financial equilibrium theory, the real assets model (RA-Model). Households in the LT-Model trade goods together with claims to Lucas trees (exogenous stochastic dividend streams specified in terms of a particular good) and long-lived, zero-net-supply real bonds, and are endowed with share portfolios. The RA-Model is quite similar to the LT-Model except that the only claims traded there are zero-net-supply assets paying out in terms of commodity bundles (real assets) and households' endowments are in terms of commodity bundles as well. At the outset, one would expect the two models to deliver similar implications since the LT-Model can be transformed into a special case of the RA-Model. We demonstrate that this is simply not correct: results obtained in the context of the LT-Model can be strikingly different from those in the RA-Model. Indeed, specializing households' preferences to be additively separable (over time) as well as log-linear, we show that for a large set of initial portfolios the LT-Model -- even with potentially complete financial markets -- admits a peculiar financial equilibrium (PFE) in which there is no trade on the bond market after the initial period, while the stock market is completely degenerate, in the sense that all stocks offer exactly the same investment opportunity -- and yet, allocation is Pareto optimal. We then thoroughly investigate why the LT-Model is so much at variance with the RA-Model, and also completely characterize the properties of the set of PFE, which turn out to be the only kind of equilibria occurring in this model. We also find that when a PFE exists, either (i) it is unique, or (ii) there is a continuum of equilibria: in fact, every Pareto optimal allocation is supported as a PFE. Finally, we show that most of our results continue to hold true in the presence of various types of restrictions on transactions in financial markets. Portfolio constraints however may give rise other types of equilibria, in addition to PFE. While our analysis is carried out in the framework of the traditional two-period Arrow-Debreu-McKenzie pure exchange model with uncertainty (encompassing, in particular, many types of contingent commodities), we show that most of our results hold for the analogous contin
97. The Forest Trees of North America
• date - 1891-01-01T00:00:00Z
• creator - Gray, Asa
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Plates prepared between the years 1849 and 1859, to accompany a report on the Forest Trees of North America
98. Taxoids: New Weapons against Cancer
• date -
• creator - Nicolaou, Guy, Potier
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=1EDB50C0-6D2F-4745-BC2A-BA2958EDC9E&ARTICLEID_CHAR=77B02A74-FD33-43C8-B0ED-7B0FCE1C967
99. Endpoints
• date -
• creator - Staff Editors
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=AAA12C8C-CA2A-45B9-9DBB-2FCA0815FCB&ARTICLEID_CHAR=A05336A0-0EDF-4D01-8E88-103197D6673
• description - Benjamin Burr and Frances Burr, biologists at Brookhaven National Laboratory, offer this explanation: Fruit development normally begins when one or more egg cells in the ovular compartment of the flower are fertilized by sperm nuclei from pollen. In some plants, however, fruit develops without fertilization, a trait called parthenocarpy. Parthenocarpic fruit has advantages over seeded fruit: longer shelf life and greater consumer appeal.The most frequent reasons for lack of seed development are pollination failure or nonfunctional eggs or sperm. In many plants, self-incompatibility genes limit successful fertilization to cross-pollination between genetically different male and female parents. This property is exploited by citrus farmers who grow seedless fruits, such as navel oranges and clementines. These cultivars fail to set seed when they are planted in orchards of identical plants (clones). They are parthenocarpic, though, so they still produce fruit. Such trees do not require seed for propagation. In fact, propagation by seed would be disadvantageous because the progeny would differ from the parent. Rather nurserymen frequently propagate fruit trees asexually, usually by grafting.
100. Mathematical Recreations
• date -
• creator - Stewart
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=D46DE786-2844-4B0E-ADEE-82717DB462F&ARTICLEID_CHAR=5AB34619-40C9-4F9F-B6F4-F55866560DF
• description - One of nature's most spectacular displays occurs soon after sunset in Southeast Asia, where swarms of fireflies flash in synchrony. As biologist Hugh M. Smith wrote in the 1930s [see "Synchronous Fireflies," by John and Elisabeth Buck; Scientific American, May 1976]:Imagine a tree thirty-five to forty feet high...apparently with a firefly on every leaf and all the fireflies flashing in perfect unison at the rate of about three times in two seconds, the tree being in complete darkness between flashes...Imagine a tenth of a mile of river front with an unbroken line of [mangrove] trees with fireflies on every leaf flashing in synchronism, the insects on the trees at the ends of the line acting in perfect unison with those between. Then, if one's imagination is sufficiently vivid, he may form some conception of this amazing spectacle.
101. 8.592 Statistical Physics in Biology, Spring 2003
• date - 2006-11-20T10:50:22Z
• creator - Kardar, Mehran
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/34906
• description - A survey of problems at the interface of statistical physics and modern biology: Bioinformatic methods for extracting information content of DNA; gene finding, sequence comparison, phylogenetic trees. Physical interactions responsible for structure of biopolymers; DNA double helix, secondary structure of RNA, elements of protein folding. Considerations of force, motion, and packaging; protein motors, membranes. Collective behavior of biological elements; cellular networks, neural networks, and evolution.
102. Phosphorus Fertilization Increases the Abundance and Nitrogenase Activity of the Cyanolichen Pseudocyphellaria crocata in Hawaiian Montane Forests
• date - 2007-05
• creator - Benner, Jon W.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00267.x
• description - ABSTRACT Nitrogen-fixing epiphytes (especially lichens with a cyanobacterial symbiont—cyanolichens) have the potential to contribute significant amounts of nitrogen (N) to montane tropical forests, which are typically low in N—but the factors controlling the abundance and distribution of epiphytic cyanolichens are poorly understood. In long-term fertilization experiments in montane forests on a 4.l million-yr-old Oxisol on the island of Kauà'i and on a 152-yr-old lava flow on the island of Hawai'i, the epiphytic cyanolichen Pseudocyphellaria crocata increased significantly in abundance in canopies of host trees fertilized with phosphorus (P). There was no response to fertilization with N or other essential elements. Nitrogen-fixation rates were also elevated in lichens in P-fertilized plots at both sites. Phosphorus supply to host trees may be an important factor controlling N inputs to montane tropical forests by N-fixing epiphytes.
103. The Effect of Herbaceous Understory Cover on Fruit Removal and Seedling Survival in Coastal Dune Forest Trees in South Africa
• date - 2007-05
• creator - Tsvuura, Zivanai
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00270.x
• description - ABSTRACT Regeneration of forest canopy trees can be inhibited by understory thickets. We hypothesized that Isoglossa woodii, a large-leaved herbaceous plant, limits tree recruitment in subtropical coastal dune forests by providing habitat to fruit and seedling consumers. Using uncaged and caged treatments in I. woodii gaps and thickets, we found that frugivore and herbivore behavior is not influenced by I. woodii. We conclude that direct effects of I. woodii on postemergence processes in seedlings contribute to tree recruitment limitation.
104. The Bushmeat Harvest Alters Seedling Banks by Favoring Lianas, Large Seeds, and Seeds Dispersed by Bats, Birds, and Wind
• date - 2007-05
• creator - Wright, S. Joseph
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00289.x
• description - ABSTRACT We evaluated predictions that hunters favor lianas, large seeds, and seeds dispersed by bats, small birds, and mechanical means for seedling banks in central Panama. We censused 3201 trees in 20 1-ha plots and 38,250 seedlings in the central 64 m2 of each plot. We found significant differences in the species composition of the seedling bank between nine protected sites in the Barro Colorado Nature Monument and 11 hunted sites in the contiguous Parque Nacional Soberanía. Lianas, species with large seeds, and species with seeds dispersed by bats, small birds, and mechanical means were all overrepresented at hunted sites. The latter two findings could also be evaluated relative to the species composition of reproductively mature adults for canopy trees. The tree species present in the seedling bank had significantly heavier seeds than the tree species present as adults at hunted sites but not at protected sites. The representation of seed dispersal modes among the species present in the seedling bank did not reflect pre-existing differences in the local species composition of adults. We hypothesize that hunting large seed predators favors large seeds by reducing predation and increasing survival. We also hypothesize that the harvest of large birds and mammals that disperse many seeds favors other species whose seeds are dispersed by bats, small birds, and mechanical means. This process also favors lianas because the seeds of disproportionate numbers of liana species are dispersed by wind.
105. Scale-Dependent Effects of Habitat Fragmentation on Hawthorn Pollination, Frugivory, and Seed Predation
• date - 2007-04
• creator - GARCÍA, DANIEL
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.2006.00593.x
• description - Abstract:  Habitat fragmentation is a major cause of functional disruption in plant-animal interactions. The net effect on plant regeneration is, however, controversial because a given landscape change can simultaneously hamper mutualism and attenuate antagonism. Furthermore, fragmentation effects may emerge at different spatial scales, depending on the size of the foraging range of the different interacting animals. We studied pollination by insects, frugivory by birds acting as seed dispersers, and postdispersal seed predation by rodents in 60 individual hawthorn (Crataegus monogyna Jacq.) trees in relation to structural fragmentation in the surrounding habitat. We evaluated fragmentation at three spatial scales by measuring the percentage of forest cover in three concentric areas around each tree of, respectively, 10-m, 20- to 50-m, and 50- to 100-m radius. The number of developing pollen tubes per flower style and fruit set decreased in proportion to the decrease of forest cover. Similarly, the magnitude of frugivory in focal trees was negatively affected by habitat loss. In contrast, seed predation was higher under plants in highly fragmented contexts. The effect of fragmentation was additive in terms of reducing the potential of plant regeneration. Moreover, the functional scale of response to habitat loss differed among interactions. Fragmentation effects on pollination emerged at the largest scale, whereas seed predation was mostly affected at the intermediate scale. In contrast to expectations from the larger foraging range of birds, fragmentation effects on frugivory mainly operated at the finest scale, favored by the ability of birds to cope hierarchically with spatial heterogeneity at different scales. Given that two opposing demographic forces (frugivory and seed predation) would be potentially affected by fine-scale features, we propose structural scale as the primary spatial dimension of fragmentation effects on the process of plant regeneration.
106. News Scan Briefs
• date -
• creator - JR Minkel, Philip Yam, Steven Ashley, Staff Editors
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=FAD0862F-6088-4FF2-8345-64ACD2A0BD6&ARTICLEID_CHAR=BC2D6309-93A8-4AA2-A843-EDC2DAAB76A
• description - The Fat Just Melts Away: Mutant mice can now emulate those forever-slim folks who eat whatever they want. Rodents lacking a single fatty-acid-producing gene called SCD-1 gorged on high-fat, sucrose-rich diets without packing on the pounds or sending their blood into a diabetes-inducing sugar rush. Instead they seemed to burn up the excess calories, judging by their oxygen consumption. The skin and eyes of the animals became dry as time went on, but those mice producing half the normal amount of the enzyme gained less weight than normal rodents and did not have obvious side effects, says lead investigator James M. Ntambi of the University of Wisconsin-Madison. This suggests that a tolerable drug to protect people from obesity and diabetes might be found, he explains. Human SCD-1 is currently being analyzed. The study appeared in the August 12 online version of the Proceedings of the National Academy of Sciences USA.-JR MinkelSidling Up to the Rich: If you want to attract birds, think upper crust. Ann P. Kinzig and Paige S. Warren of Arizona State University found that the birds of Phoenix prefer the greenery of well-to-do neighborhoods over that in lower-income areas. Parks of the well-heeled contained an average of 28.2 species year-round, compared with 17.5 in depressed locales; middle-class parks fell in between, attracting 23.2 species. The researchers thought that the abundance and diversity of trees caused the disparities. Surprisingly, the vegetation factors did not correlate with the bird data-in fact, poor neighborhoods had a greater diversity of trees. It isn't the snazzy address that draws the feathers, of course. Socioeconomic status, Kinzig notes, is a surrogate for many possible reasons, such as landscaping or commercial activity, that may affect avian preferences. The results were presented at the August meeting of the Ecological Society of America.-Philip Yam
107. Floral Fiend
• date -
• creator - Mirsky
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=59391E73-6FFE-4B08-88D1-DD135742092&ARTICLEID_CHAR=CEA2CDED-A616-4309-A88F-2CF5FDAE81F
• description - From a few hundred yards away, an emerald cloak gives the cypress trees I'm approaching an unfocused, impressionistic look. At a few dozen yards, individual fronds of the cloak resolve themselves: the trees now look as if they're dripping with green sequins. Up close, however, these fanciful images give way to a harsh reality: I'm in the midst of botanical carnage. Most of the vegetation beneath the verdant surface is dead, and the spongy ground underfoot chiefly comprises a disorderly tangle of brownish, dried strands of the very stuff that elegantly drapes everything in sight. This cypress stand at Jonathan Dickinson State Park in Hobe Sound, just north of West Palm Beach, Fla., has been taken over by an alien invader: Lygodium microphyllum, a.k.a. Old World climbing fern.Michael Lott, a graduate student at Florida Atlantic University (F.A.U.), is showing me around, like a combat vet escorting a reporter through a war zone. The fern chokes off its victims from their light supply, and it has additional nefarious talents. "Fire gets in," Lott explains, "and just explodes the dry material"-the stuff underfoot-"into the tree canopy." Controlled burns can become uncontrolled infernos.
108. Persistence of Forest Birds in the Costa Rican Agricultural Countryside
• date - 2007-04
• creator - SEKERCIOGLU, CAGAN H.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.2007.00655.x
• description - Abstract:  Understanding the persistence mechanisms of tropical forest species in human-dominated landscapes is a fundamental challenge of tropical ecology and conservation. Many species, including more than half of Costa Rica's native land birds, use mostly deforested agricultural countryside, but how they do so is poorly known. Do they commute regularly to forest or can some species survive in this human-dominated landscape year-round? Using radiotelemetry, we detailed the habitat use, movement, foraging, and nesting patterns of three bird species, Catharus aurantiirostris, Tangara icterocephala, and Turdus assimilis, by obtaining 8101 locations from 156 individuals. We chose forest birds that varied in their vulnerability to deforestation and were representative of the species found both in forest and human-dominated landscapes. Our study species did not commute from extensive forest; rather, they fed and bred in the agricultural countryside. Nevertheless, T. icterocephala and T. assimilis, which are more habitat sensitive, were highly dependent on the remaining trees. Although trees constituted only 11% of land cover, these birds spent 69% to 85% of their time in them. Breeding success of C. aurntiirostris and T. icterocephala in deforested habitats was not different than in forest remnants, where T. assimilis experienced reduced breeding success. Although this suggests an ecological trap for T. assimilis, higher fledgling survival in forest remnants may make up for lower productivity. Tropical countryside has high potential conservation value, which can be enhanced with even modest increases in tree cover. Our findings have applicability to many human-dominated tropical areas that have the potential to conserve substantial biodiversity if appropriate restoration measures are taken.
109. Estimating Dependency Structure as a Hidden Variable
• date - 2004-10-20T21:04:25Z
• creator - Meila, Marina
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/7257
• description - This paper introduces a probability model, the mixture of trees that can account for sparse, dynamically changing dependence relationships. We present a family of efficient algorithms that use EM and the Minimum Spanning Tree algorithm to find the ML and MAP mixture of trees for a variety of priors, including the Dirichlet and the MDL priors. We also show that the single tree classifier acts like an implicit feature selector, thus making the classification performance insensitive to irrelevant attributes. Experimental results demonstrate the excellent performance of the new model both in density estimation and in classification.
110. Jumbo Trouble
• date -
• creator - Ezzell
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=82D7E940-CBFE-4BD2-989F-A47BDEAACE1&ARTICLEID_CHAR=7F2897E0-EFF3-4BC6-A92E-1B8FCF99B3D
• description - One of the first things a visitor to Hwange National Park in northwest Zimbabwe notices is the trees-or rather the paucity thereof. Everywhere one looks, young saplings and middling trees have been bent back, snapped off and generally broken down, their dry branches hanging at odd angles. Some have deep pits at their bases that expose their spindly roots to the surface. Has Hwange been hit by a storm? No, it's the work of elephants-lots of elephants.For more than a decade now, environmentalists' concerns over the African elephant have centered on the damage that poachers wreaked on the species as they slaughtered animals for their ivory tusks. In 1988 elephant maven Cynthia Moss of the African Wildlife Foundation estimated that 80,000 were being killed annually, a rate that had slashed African elephant populations by half since 1979. Most of the slaughter occurred in eastern and central Africa.
111. Estimating Dependency Structure as a Hidden Variable
• date - 2004-10-20T21:04:00Z
• creator - Meila, Marina
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/7245
• description - This paper introduces a probability model, the mixture of trees that can account for sparse, dynamically changing dependence relationships. We present a family of efficient algorithms that use EMand the Minimum Spanning Tree algorithm to find the ML and MAP mixtureof trees for a variety of priors, including the Dirichlet and the MDL priors.
112. Storage and management of similar images
• date - 2000
• creator - Rukoz Marta
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01046500&date=2000&volume=6&issue=3&spage=13
• description - Numerical images are becoming more and more important and an increasing emphasis on multimedia applications has resulted in large volumes of images. However, images need a large memory space to be stored, so their efficient storage and retrieval generate challenges to the database community. This paper proposes a new algorithm for an efficient storage of sets of images. It is based on a version approach used in databases. It shows how to store and operate on similar images; two images are defined as similar if the quad-trees encoding them have only few different nodes. A data structure called Generic Quad-Tree (GQT) is proposed. It optimizes the memory space required to store similar images and allows an efficient navigation among them. An Image Tree stores the ancestors and descendants of an image, like a version hierarchy. Using the Image Tree, the Generic Quad-Tree allows an image to share common parts with its ancestors and descendants. The GQT approach and some algorithms for reading, modifying or removing images from the Generic Quad-Tree are described. Examples using black and white images and gray scale images are presented.
113. Spectrum of some regular graphs with widely spaced modifications
• date - 2005-08-23T18:25:50Z
• creator - Liu, Xiangwei, 1976-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/8224
• description - This thesis has two parts. The first part studies the spectrum of a family of growing trees, we show that the eigenvalues of the adjacency matrix and Laplacian matrix have high multiplicities. As the trees grow, the graphs of those eigenvalues approach a piecewise-constant "Cantor function", which is different from the corresponding properties of the infinite tree. The second part studies the effect of "widely spaced" modifications on the spectrum of some type of structured matrices. We show that by applying those modifications, new eigenvectors that are localized near the components that correspond to the modified rows appear. By knowing the approximate form of those eigenvectors, we also determine a very close (and simple) approximation to the eigenvalues, and then we show that this approximation is indeed the limit as the matrix grows.
114. Essay:The Tragedy of Enclosure
115. 6.034 Artificial Intelligence, Spring 2003
• date - 2007-01-25T04:57:58Z
• creator - Lozano-Perez, Tomas
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/35799
• description - Introduces representations, techniques, and architectures used to build applied systems and to account for intelligence from a computational point of view. Applications of rule chaining, heuristic search, constraint propagation, constrained search, inheritance, and other problem-solving paradigms. Applications of identification trees, neural nets, genetic algorithms, and other learning paradigms. Speculations on the contributions of human vision and language systems to human intelligence. Enrollment may be limited.
116. These Feet Were Made for Walking - and?
• date -
• creator - Beardsley
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=17A14774-EE98-4B7D-8AF9-290B5EDDD7A&ARTICLEID_CHAR=F01DD93C-1298-48DD-A149-D941E78E9E0
• description - Sometime during the past few million years, our many great-grandparents came down from the trees and started to walk on the ground. Although there is no consensus about when exactly the switch happened, a recent scientific report about four wellpreserved foot bones found in Sterkfontein Cave near Johannesburg has rekindled the long-standing dispute.The report, published in Science by Ronald J. Clarke and Philip V. Tobias of the University of Witwatersrand, concludes that the owner of the bones--an australopithecine possessed of a humanlike heel and able to walk on two legs--had a big toe that diverged from the other toes, somewhat as a thumb diverges from the fingers. The reconstructed foot, dubbed "Littlefoot" and estimated to be about 3.5 million years old, looks like a chimpanzee's, the authors suggest, and so was probably used to help climb trees. Other foot bones from that time have been described in the literature before, but Littlefoot 's bones are unusual in that they fit together exactly.
117. Virtual layering and efficient merging in non-cooperative multicast trees
• date - 2001
• creator - Pujolle Guy
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01046500&date=2001&volume=7&issue=2&spage=28
• description - A critical problem faced by feedback-merger mechanisms is the lack of information that is discarded due to the hidden nodes in multicast trees. A node is said to be hidden from another if it is located in a sub tree that is a result from a fork in any upstream node. We propose in this paper the virtual layering scheme to avoid the problem caused by hidden-nodes in multi-layered multicast video environments. The virtual layering scheme induces intermediate nodes to keep extra states of the multicast session, which reduces the video degradation for the whole set of receivers. Furthermore, this scheme is coupled with the Direct Algorithm in order to improve the degree of satisfaction at heterogeneous receivers. The algorithm relies on a mechanism that dynamically controls the rates of the video layers and addresses scalability issues by implementing a merging procedure at intermediate nodes in order to avoid packet implosion at the source. The Virtual Layering scheme combined with the Direct Algorithm is optimized to achieve high global video quality and reduced bandwidth requirements. The results show that the proposed scheme leads to improved global video quality at heterogeneous receivers with no cost of extra bandwidth.
118. Out of Place
• date -
• creator - Wallach
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=3450D653-FD49-4319-B5FD-8491E64052D&ARTICLEID_CHAR=7A5A5F1B-05ED-45BD-BBFC-B232DE3363E
• description - The fate of a fast-growing shrub in Southeast Asia and tropical Africa could pit small farmers against large plantation managers, with agricultural researchers forced to take sides. Chromolaena odorata is not much to look at, but it has spread so rapidly in Africa, according to Joan Baxter of the International Center for Research in Agroforestry (ICRAF) in Nairobi, that local names for it have cropped up: Bokassa (the dictator of the Central African Republic from 1966 to 1979, who had himself crowned emperor in 1977 in a lavish ceremony that bankrupted his subjects), l'envahisseur (the invader) and mighbe (the plant that crushes all) in Cameroon.The shrub, which grows up to five meters high, plagues coconut, oil palm and rubber plantations. If it is not suppressed, it can shade infant trees and prevent them from growing. It also creates a wall of impassable undergrowth that makes harvesting mature trees almost impossible. And labor for weeding of enormous tracts is expensive.
119. The reclamation of the Everglades with trees [electronic resource] / by John C. Gifford.
120. News Scan Briefs
• date -
• creator - Charles Choi, Sarah Simpson, JR Minkel, Chris Jozefowicz
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=B2CCC382-2B35-221B-6FB9BB706EFFA096&ARTICLEID_CHAR=B2DA5274-2B35-221B-645331616CFFFE59
• description - Shrinking to Enlarge: Wheat and rice half as tall as their normal counterparts helped to thwart famine all over India and southeast Asia in the 1960s. Rather than using energy for height, the stunted crops put it toward making grain instead, quadrupling production in some cases. Investigators have now identified a genetic mutation that can keep corn and sorghum from growing tall, which could improve food yields globally. Researchers at Purdue University found that the mutation shuts down production of a sugary protein that controls the flow of auxin, a plant growth hormone. The resulting dwarf crops also have more cells pound for pound in their stalks, making them stronger and perhaps more effective at holding water. Dwarf sorghum could play a key role in Africa, where it is often a staple. Other crops that usually grow tall, such as basmati rice in India and teff, which is cultivated primarily in Ethiopia, may also benefit. The scientists discuss their findings in the October 3 Science.-Charles ChoiLeaving Alone: The radiant oranges of a monarch butterfly's wings alert hungry predators that those insects are poison. In much the same way, the dazzling orange, red and yellow displays of forests in fall may be warning would-be leaf munchers of a tree's chemical defenses. Invertebrate biologist Snorre Hagen and his team at the University of Tromso in Norway monitored the leaves and flowers of a dozen mountain birch trees for two years. Scientists have long thought that the bright colors of autumn foliage were just the byproduct of how leaves age when they cease photosynthesis, but Hagen and his colleagues report that the earlier and the more trees changed color, the less damage from chewing occurred the following season. Their report, in the September Ecology Letters, also notes that leaf chemistry analyses and tests with color-sensitive herbivores are needed to uncover the mechanisms that reduce insect damage.-Charles Choi
121. 6.046J / 18.410J Introduction to Algorithms, Fall 2001
• date - 2007-03-16T14:04:23Z
• creator - Demaine, Erik D.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36847
• description - Techniques for the design and analysis of efficient algorithms, emphasizing methods useful in practice. Topics: sorting; search trees, heaps, and hashing; divide-and-conquer; dynamic programming; amortized analysis; graph algorithms; shortest paths; network flow; computational geometry; number-theoretic algorithms; polynomial and matrix calculations; caching; and parallel computing. Enrollment may be limited.
122. Photographs mainly of Marjory Stoneman Douglas, 1923-1926. [electronic resource]
• date - 1923-1926
• creator - Douglas, Marjory Stoneman
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTMD00370099.jpg
• description - Electronic reproduction. Miami, Fla. : Reclaiming the Everglades, c2000. Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software. Digitized from photographs held by Richter Library, University of Miami, Coral Gables, Florida.
123. Everglades photographs, ca. 1920-1930. [electronic resource]
• date - 1920-1930
• creator - Douglas, Marjory Stoneman
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTMD00360001.jpg
• description - Electronic reproduction. Miami, Fla. : Reclaiming the Everglades, c2000. Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software. Digitized from photographs at Richter Library, University of Miami, Coral Gables, Florida.
124. 16.410 / 16.413 Principles of Autonomy and Decision Making, Fall 2003
• date - 2007-03-28T11:29:57Z
• creator - Williams, Brian C.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36896
• description - This course surveys a variety of reasoning, optimization, and decision-making methodologies for creating highly autonomous systems and decision support aids. The focus is on principles, algorithms, and their applications, taken from the disciplines of artificial intelligence and operations research. Reasoning paradigms include logic and deduction, heuristic and constraint-based search, model-based reasoning, planning and execution, reasoning under uncertainty, and machine learning. Optimization paradigms include linear, integer and dynamic programming. Decision-making paradigms include decision theoretic planning, and Markov decision processes. This course is offered both to undergraduate (16.410) students as a professional area undergraduate subject, in the field of aerospace information technology, and graduate (16.413) students.
125. Creating a Sustainable Planet
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://awesomelibrary.org/SustainablePlanet.html
• description - Awesome Library shows what we can do as individuals to reduce global warming and pollution by reducing fossil fuel usage, increasing the number of trees, and improving the availability of safe drinking water.
126. Effect of lime, gypsum and potassium chloride on growth and nutrient uptake of longkong (Aglaia dookkoo Griff.) seedlings
• date - 2007
• creator - Malee, N.
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2007&volume=29&issue=3&spage=655
• description - Application of lime and gypsum for alleviation of aluminum toxicity in acid soil, including potassium (K) fertilization, may interfere with the nutrient uptake of longkong (Aglaia dookkoo Griff.) trees. Threeexperiments were conducted to explore the possible problem of longkong soil. 1) Effect of lime and gypsum on growth and nutrient uptake of longkong seedling. 2) Effect of lime and potassium chloride on potassiumand magnesium uptake of longkong. 3) Relationship between potassium, calcium and magnesium in longkong leaves. The results showed that exchangeable aluminum in the soil decreased with the increase of Ca(OH)2 treatment and the application of lime was more effective than that of the gypsum treatment. Theapplication of lime and gypsum tended to increase nutrient concentration in longkong, but did not affect the growth of longkong seedlings. The lime application on nutrient uptake of longkong seedlings decreased Kuptake; no lime and lime treatments were 863 and 720 mg tree-1, while without K applied the per tree uptakes were 579 and 356 mg tree-1 respectively. Besides the K application treatment reduced Ca and Mg uptake.Negative correlations between K and Ca (r = -0.532**) and between K and Mg (r = -0.663**) in leaves of 60 longkong trees in a farmer's orchard were found.
127. Diving for Dead Wood
128. TREES, SHRUBS, AND WOODY VINES OF NORTHERN FLORIDA AND ADJACENT GEORGIA AND ALABAMA
• date - 1988
• creator - GODFREY, R. K.
• provider - NSDL OAI Repository
• location -
• description -
129. 6.046J Introduction to Algorithms (SMA 5503), Fall 2004
• date - 2007-04-09T12:10:58Z
• creator - Leiserson, Charles Eric
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/37150
• description - Techniques for the design and analysis of efficient algorithms, emphasizing methods useful in practice. Topics: sorting; search trees, heaps, and hashing; divide-and-conquer; dynamic programming; amortized analysis; graph algorithms; shortest paths; network flow; computational geometry; number-theoretic algorithms; polynomial and matrix calculations; caching; and parallel computing. Enrollment may be limited.
130. tree (set theoretic)
• date - 2007-08-20
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/TreeSetTheoretic.html
• description - In a set, a ... tree is defined to be a set <i>T</i> and a relation ... such that: ... is a partial ordering of <i>T</i> ... For any ... , ... is well-ordered ... The nodes (elements of the tree) immediately greater than a node are termed its ... children , the node immediately less is its ... parent (if it exists), any node less is an ... ancestor and any node greater is a ... descendant . A node with no ancestors is a ... root . The partial ordering represents from the root, and the well-ordering requirement prohibits any loops or splits below a node (that is, each node has at most one parent, and therefore at most one grand-parent, and so on). Conversely, if ... then there is exactly one ... such that ... and there is nothing between <i>a</i> and <i>b</i>. Note that there is no requirement that a node have a parent--there could be an infinitely long branch ... with each ... . Since there is generally no requirement that the tree be connected, the null ordering makes any set into a tree, although the tree is a trivial one, since each element of the set forms a single node with no children. Since the set of ancestors of any node is well-ordered, we can it with an ordinal. We call this the ... height , and write: ... . This all accords with usage: a root has height <i>0</i>, something immediately above the root has height <i>1</i>, and so on. We can then assign a height to the tree itself, which we define to be the least number greater than the height of any element of the tree. For finite trees this is just one greater than the height of its tallest element, but infinite trees may not have a tallest element, so we define ... . For every ... we define the alpha-th ... level to be the set ... . So of course ... is all roots of the tree. If ... then ... is the subtree of elements with height less than alpha: ... . We call a tree a kappa-tree for any cardinal kappa if ... and ... . If kappa is finite, the only way to do this is to have a single branch of length kappa.
131. Broken Dreamtime
• date -
• creator - Stix
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=850C0446-E166-43CE-B484-54DAB90A59E&ARTICLEID_CHAR=0EAEF7A7-C38C-4377-A902-7633F984D3D
• description - The bushfires that raged in the past year or so during one of the worst dry spells in recent Australian history destroyed scores of houses. They also consumed trees that are home to animals that have helped sell airplane tickets to tourists visiting this island continent. The blazes put an additional strain on diminishing koala habitat: the land where these creatures live in eastern Australia is increasingly being sought by real-estate developers.Koalas have come to live cheek-by-snout with people moving into coastal areas populated with the animals ' prized food. Koalas prefer to eat the leaves of less than a dozen of the 650 native varieties of eucalyptus trees. Undeniably, the past 100 years have not been good to this marsupial (koalas are bears only in their resemblance to the genus Teddy). Millions of pelts went to England around the turn of the century as a soughtafter, cheap and durable fur.
132. The Sound of One Tree Breathing
• date -
• creator - Schneider
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=A12504E9-7B46-43F0-894A-8025E9E95FB&ARTICLEID_CHAR=38BAECAE-BD91-49E0-9B05-3D2BEB20E2C
• description - As part of the Southern Oxidants Study, Environmental Protection Agency researchers and their colleagues at Duke University are conducting experiments to determine the amount of volatile organic compounds (VOCs) given off by some native tree species. Such natural hydrocarbons are of particular concern because they can react with oxides of nitrogen to form lowlevel ozone, a serious atmospheric pollutant.In order for the EPA to formulate strategies to control levels of hydrocarbons and nitrogen oxides resulting from human activity, researchers must establish the rates at which trees release VOCs. Some studies have suggested that in the U.S., naturally occurring volatile organics might exceed those introduced by cars or manufacturing. But these estimates are highly uncertain, and more direct measurements of biogenic sources are sorely needed. So a few trees must suffer in temporary confinement while their effusions are collected and carefully measured (right ). At least no one is trying to make gasoline this way.
133. Getting the Goats
134. Preserving the Laetoli Footprints (Part 2)
• date -
• creator - Agnew, Demas
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8DB2FB44-6B4B-47AF-B46B-791A911764D&ARTICLEID_CHAR=974C3008-24FF-4130-AE74-588FCF6CBA4
• description - Fieldwork on the Laetoli footprints ended with the 1979 season, and LeakeyFs team used local river sand to rebury the site. Because the tuff is soft and easily damaged, the mound of sand was covered with volcanic boulders to armor it against erosion and the animals that sometimes roam across the site--particularly elephants and the cattle of the Masai people living in the area. We now know that seeds of Acacia seyal, a large, vigorously growing tree species, were inadvertently introduced with the reburial fill. The loose fill and the physical protection and moisture retention provided by the boulders created a microenvironment conducive to germination and rapid plant growth. Over the following decade, the acacias and other trees grew to heights of over two meters. Scientists who occasionally visited the Laetoli site began to voice concern that the roots from these trees would penetrate and eventually destroy the hominid footprints.In 1992 the Antiquities Department of the Tanzanian government approached the Getty Conservation Institute, which has extensive experience in preserving archaeological sites, to consider how the trackway might be saved. The following year a joint team from the institute and the Antiquities Department excavated a sample trench in the reburial mound to assess the condition of the hominid footprints. The assessment revealed that tree roots had indeed penetrated some of the tracks. But in the areas where no root damage had occurred, the preservation of the prints was excellent. LeakeyFs intuitive decision to rebury the site had been the right one. With hindsight we can now say that perhaps greater care should have been taken in how the site was buried. Also, periodic monitoring and maintenance--including the removal of tree seedlings before they became established--would have avoided the need for a long and costly conservation effort.
135. A Constant-Factor Approximation Algorithm for Embedding Unweighted Graphs into Trees
• date - 2005-12-22T01:35:27Z
• creator - Badoiu, Mihai
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30484
• description - We present a constant-factor approximation algorithm for computing anembedding of the shortest path metric of an unweighted graph into atree, that minimizes the multiplicative distortion.
136. Correspondence relating to the creation of Everglades National Park, 1928-1931. [electronic resource]
• date -
• creator - Model Land Company.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTML00751439.jpg
• description - Electronic reproduction. Miami, Fla. : Reclaiming the Everglades, c2000. Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software. Digitized from papers at Richter Library, University of Miami, Coral Gables, Florida.
137. paradox of the binary tree
• date - 2007-05-13
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/ParadoxOfTheBinaryTree.html
• description - The ... complete infinite binary tree is a tree that consists of nodes (namely the numerals <i>0</i> and <i>1</i>) such that every node has two children which are not children of any other node. The tree serves as Base3 of all real numbers of the interval ... in form of paths, Ie , sequences of nodes. Every finite binary tree with more than one level contains less paths than nodes. Up to level <i>n</i> there are ... paths and ... nodes. Every finite binary tree can be represented as an ordered set of nodes, enumerated by natural numbers. The union of all finite binary trees is then identical with the infinite binary tree. The paradox is that, while the set of nodes remains countable as is the set of paths of all finite trees, the set of paths in the infinite tree is uncountable by Cantor's theorem. (On the other hand, the paths are separated by the nodes. As no path can separate itself from another path without a node, the number of separated paths is the number of nodes.) ... Literature W. M\"uckenheim: Die Mathematik des Unendlichen, Shaker-Verlag, Aachen 2006.
138. In the Heat of the Night
• date -
• creator - Beardsley
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=07C2E454-8DC1-46F7-BE85-4068FD11960&ARTICLEID_CHAR=DE058169-494A-46FB-999E-B42013E0E97
• description - Researchers working in Costa Rica have discovered disturbing evidence that increasing temperatures have markedly slowed the growth of tropical trees over the past decade. The slowdown may explain calculations suggesting that tropical forests, which are usually considered to take up carbon dioxide, have actually added billions of tons of the greenhouse gas to the atmosphere each year during the 1990s, making them a huge net source, comparable in size to the combustion of fossil fuels. The trend could exacerbate global warming: as the mercury rises, tropical forests may dump yet more carbon dioxide into the atmosphere, causing still more warming.In 1984 researchers Deborah A. Clark and David B. Clark of the University of Missouri, collaborating with Charles D. Keeling and Stephen C. Piper of the Scripps Institution of Oceanography in La Jolla, Calif., began measuring the growth rates of scores of adult tropical rain-forest trees at La Selva Biological Station in central Costa Rica. The sample includes six different tree species, with both fast- and slow-growing types represented. Using special measuring collars, the scientists obtain reliable data on aboveground growth each year. Deborah Clark presented the teamFs findings in August at a meeting of the Ecological Society of America in Baltimore.
139. minimum weighted path length
• date - 2004-01-22
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/MinimumWeightedPathLength.html
• description - Given a list of weights, ... , the ... minimum weighted path length is the minimum of the weighted path length of all extended binary trees that have <i>n</i> external nodes with weights taken from <i>W</i>. There may be multiple possible trees that give this minimum path length, and quite often finding this tree is more important than determining the path length. ... Let ... . The minimum weighted path length is ... . A tree that gives this weighted path length is shown below. ... Constructing a tree of minimum weighted path length for a given set of weights has several applications, particularly dealing with optimization problems. A simple and elegant algorithm for constructing such a tree is Huffman's algorithm. Such a tree can give the most optimal algorithm for merging <i>n</i> sorted sequences (optimal merge). It can also provide a means of compressing data (Huffman coding), as well as lead to optimal searches.
140. The mandarin orange in Florida [electronic resource] : with special reference to the satsuma.
• date - [1941]
• creator -
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/UF00002892.pdf
• description - Electronic reproduction. [Florida] : Board of Education, Division of Colleges and Universities, PALMM Project, 2001. Mode of Access: World Wide Web. System Requirements: Internet connectivity; Web browser software; Adobe Acrobat Reader to view and print PDF files. Electronically reproduced from Collection in George A. Smathers Libraries at the University of Florida.
141. Tung oil : a new industry in Florida [electronic resource] / by John M. Scott.
• date - 1929
• creator - Scott, John M. (John Marcus)
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/UF00003046.pdf
• description - Scattered plantings of tung oil trees are found in nearly all parts of Florida, although at the present time (1929) the large commercial plantings are confined generally to Alachua and adjoining counties. Methods of growing and harvesting of seeds are described. A comparison of these methods with those used in China is also given.
142. Florida Trees
• date - 1909
• creator - Gifford, John C.
• provider - NSDL OAI Repository
• location -
• description - May also be titled, List of trees of the state of Florida.
143. groups that act freely on trees are free
• date - 2006-09-07
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/GroupsThatActFreelyOnTreesAreFree.html
• description - ... Groups that act freely and without inversions on trees are free. ... Let Gamma be a group acting freely and without inversions by graph automorphisms on a tree <i>T</i>. Since Gamma acts freely on <i>T</i>, the quotient graph ... is well-defined, and <i>T</i> is the universal cover of ... since <i>T</i> is contractible. Thus by faithfulness ... . Since any graph is homotopy equivalent to a wedge of circles, and the fundamental group of such a space is free by Van Kampen's theorem, Gamma is free. ...
144. StreetScenes : towards scene understanding in still images
• date - 2007-07-18T13:05:57Z
• creator - Bileschi, Stanley Michael, 1978-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/37896
• description - Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.
145. Modular data structure verification
• date - 2007-08-29T19:06:53Z
• creator - Kuncak, Viktor (Viktor Jaroslav), 1977-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/38533
• description - Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.
146. Investigation of the Fundamental Reliability Unit for Cu Dual-Damascene Metallization
• date - 2003-12-20T19:40:48Z
• creator - Gan, C.L.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/3976
• description - Singapore-MIT Alliance (SMA)
147. The Bertie - Twootie Home Page
• date - 2007-07
• creator - Austen Clark
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=133FFC0E-5E3B-4357-9499-E34073F4D584
• description - Three programs for computing truth (trees) in propositional and predicate logic. " Bertie3 and Twootie 2 are programs that allow students to check their solutions in natural deduction or true trees respectively. Students who practice with the programs get much better at applying the rules of such systems. Both programs are DOS programs, but they will run in a DOS window on machines running Windows (95 and up). No MacIntosh versions are available. In contrast, the third program (twoocon) is a native Windows program, and it also compiles and runs in Linux. It is a console (or command-line) version of the parser and inference engine of Twootie 2. The source code for it (and the other programs) is available. If you are interested in doing some open-source programming, please check it out. All of these programs are copyright (c) by Austen Clark, and distributed as "free" or "open source" programs under the provisions of the GNU General Public License. "
148. The uniqueness of palms
• date - 2006-05
• creator - TOMLINSON, P. BARRY
• provider - NSDL OAI Repository
• location - Botanical Journal of the Linnean Society 151(1), 5-14.
• description - Palms build tall trees entirely by primary growth in a way that limits their growth habit, but not their capacity for continued stem development. They achieve massive primary stature because of distinctive features of leaf development, stem vasculature and anatomical properties. They exhibit several record features of leaf and seed, and inflorescence size and leaves of great complexity. A marked ability to generate new roots allows them to be transplanted easily. As climbing plants they develop the longest unrooted stems in which there are, paradoxically, anomalous features of vascular construction compared with tree palms. It is here claimed that they are the world’s longest lived trees because stem cells of several kinds remain active in differentiated tissues throughout the life of the palm. Absence of physiological dormancy may be related to this property, together with inability to withstand freezing temperatures that would cause irreversible cavitation of tracheary elements. This largely restricts them to the tropics, for which they are emblematic organisms. In these biological features palms are indeed unique organisms. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 5–14.
149. Heuristics, LPs, and Trees on Trees: Network Design Analyses
• date - 2004-05-28T19:31:21Z
• creator - Magnanti, Thomas L.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5277
• description - We study a class of models, known as overlay optimization problems, with a "base" subproblem and an "overlay" subproblem, linked by the requirement that the overlay solution be contained in the base solution. In some telecommunication settings, a feasible base solution is a spanning tree and the overlay solution is an embedded Steiner tree (or an embedded path). For the general overlay optimization problem, we describe a heuristic solution procedure that selects the better of two feasible solutions obtained by independently solving the base and overlay subproblems, and establish worst-case performance guarantees on both this heuristic and a LP relaxation of the model. These guarantees depend upon worst-case bounds for the heuristics and LP relaxations of the unlinked base and overlay problems. Under certain assumptions about the cost structure and the optimality of the subproblem solutions, both the heuristic and the LP relaxation of the combined overlay optimization model have performance guarantees of 4/3. We extend this analysis to multiple overlays on the same base solution, producing the first known worst-case bounds (approximately proportional to the square root of the number of commodities) for the uncapacitated multicommodity network design problem. In a companion paper, we develop heuristic performance guarantees for various new multi-tier. survivable network design models that incorporate both multiple facility types or technologies and differential node connectivity levels.
150. How Many Trees?
151. Stanford CS Education Library
• date - 2007-05
• creator - Nick Parlante
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=278E1502-C257-49BF-8747-F4E39FD52D45
• description - This online library collects education CS material from Stanford courses and distributes them for free. Resources include: # Pointers and Memory -- videos and materials on basic pointers # Lists and Trees -- basic and advanced materials on linked lists and binary trees # Languages -- the C and Perl languages # Unix -- using Unix # Tetris -- materials for tetris experiments
152. Effects of the Surrounding Matrix on Tree Recruitment in Amazonian Forest Fragments
• date - 2006-06
• creator - ANDRADE, ANA C. S.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.2006.00344.x
• description - Abstract:  Little is known about how the surrounding modified matrix affects tree recruitment in fragmented forests. We contrasted effects of two different matrix types, Vismia- and Cecropia-dominated regrowth, on recruitment of pioneer tree species in forest fragments in central Amazonia. Our analyses were based on 22, 1-ha plots in seven experimental forest fragments ranging in size from 1 to 100 ha. By 13 to 17 years after fragmentation, the population density of pioneer trees was significantly higher in plots surrounded by Vismia regrowth than in plots surrounded by Cecropia regrowth, and the species composition and dominance of pioneers differed markedly between the two matrix types. Cecropia sciadophylla was the most abundant pioneer in fragments surrounded by Cecropia regrowth (constituting nearly 50% of all pioneer trees), whereas densities of species in Vismia-surrounded fragments were distributed more evenly. Thus the surrounding matrix had a strong influence on patterns of tree recruitment in Amazonian forest fragments.
153. Clouds And Trees - Time Lapse (Wide Screen 16:9)
• date - 2007-00-00T00:00:00Z
• creator - C. E. Price
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
154. Discrete Mathematics for Computer Science
• date - 2006-06
• creator - Robert L. Drysdale
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=3A7C1B83-8352-4AF5-AFE9-7CCFF256FB40
• description - "Discrete Mathematics for Computer Science is the perfect text to combine the fields of mathematics and computer science. Written by leading academics in these fields, the text introduces your students to all of the mathematics they need to know, with the exception of linear algebra, to succeed in computer science. The book explores basic combinatorics, number and graph theory, logic and proof techniques, and many more topics. Appropriate for large or small class sizes, Discrete Mathematics for Computer Science can be adapted to suit your teaching style. * Suitable for either lecture-only or fully interactive, collaborative course environments * Intended for students who have completed or are simultaneously studying data structures, enhancing their understanding of hashing and trees * Provides early treatment of number theory and combinatorics, allowing students simultaneously enrolled in CS/2 to develop a practical understanding of hashing and trees. "
155. Bertrand: Symbolic Logic Problem-Solving Software for the Macintosh
• date - 2007-07
• creator - Larry A. Herzberg
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=3A921315-792B-44C2-9810-05DC08A60CAD
• description - Freeware and open source courseware with tableau-like validity testing of predicate logic formulas. "Using a decomposition/instantiation algorithm inspired by the "consistency tree" method found in Leblanc and Wisdom's textbook "Deductive Logic", Bertrand solves sets of first-order symbolic logic statements (subject-identity supported) for satisfiability (consistency), validity, and equivalence. It also checks single statements for "logical truth" and "logical falsity," and produces truth-tables for single truth-functional statements. During the solution process, Bertrand issues "status reports" which give the user insight into the method by which Bertrand constructs the tree that provides a solution to the problem. These status reports can be stepped through one at a time, or they can be turned off entirely to speed up the solution process. Once Bertrand has solved a given problem, the tree constructed in the process is displayed in a scrolling window. A summary of results is given in a separate window. If applicable, a verifying (or falsifying) truth-value assignment to relevant atomic statements is provided. Trees and truth tables can be printed or saved, as can the premises alone. The branches of each tree can be rearranged by dragging them with the mouse pointer; this enables trees to be arranged so as to fit within the indicated printed page margins.
156. Lobes of Lungs and Bronchial Trees (Labeled)
157. 1947: Reel 2: Guatemala /Lake Atitla
• date - 1947-00-00T00:00:00Z
• creator - Watson Kintner
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Guatemala City to Antigua, Atitlan to Chichicastenango; June 24-25, Cottage and shore scenes at Lake Atitlan. View of hotel and bougainvillea, gardens and houses. Olive trees planted by conquistadors. Colonial Spanish building. Coat of arms. Stone carvings, [in niches: ext. ] Covered arcade. Baroque church. Washing in churchyard. Ruined buildings and churches. Garden of hotel, buildings and laundry basin. Charcoal flat iron, trimmed trees, colonial buildings. [cu] Marketplace. Restaurant, cooking and garden. Village in valley. Volcanoes. Close-ups of natives and dress, [good color!] "Hip" method of weaving. Family; courtyard and Spanish window.[shots of volcano interjected here] Street scenes. Fountain, street scenes. Women balancing water jars.[4 ws of indiv.cu of 2 girls at 6:45] Mountain and lake; on way back to Chichicastenango. Pottery carried on back. Road. Market and people. Screened enclosures for meat. Church steps and ritual fire. Market. Sugar in blocks.
158. Respiratory System with Lungs and Bronchial Trees
159. Deficit irrigation affects seasonal changes in leaf physiology and oil quality of Olea europaea (cultivars Frantoio and Leccino)
• date - 2007-04
• creator - Morelli, G.
• provider - NSDL OAI Repository
• location - Annals of Applied Biology 150(2), 169-186.
• description - Abstract The olive tree is a traditionally nonirrigated crop that occupies quite an extensive agricultural area in Mediterranean-type agroecosystems. Improvements in water-use efficiency of crops are essential under the scenarios of water scarcity predicted by global change models for the Mediterranean region. Recently, irrigation has been introduced to increase the low land productivity, but there is little information on ecophysiological aspects and quality features intended for a sagacious use of water, while being of major importance for the achievement of high-quality products as olive oil. Therefore, deficit irrigation programmes were developed to improve water-use efficiency, crop productivity and quality in a subhumid zone of Southern Italy with good winter–spring precipitation. The response of mature olive trees to deficit irrigation in deep soils was studied on cultivars Frantoio and Leccino by examining atmospheric environment and soil moisture, gas exchange and plant water status, as well as oil yield and chemical analysis. Trees were not irrigated (rainfed) or subjected to irrigation at 66% and 100% of crop evapotranspiration (ETC), starting from pit hardening to early fruit veraison. Improvements in the photosynthetic capacity induced by increasing soil water availability were only of minor importance. However, plant water status was positively influenced by deficit irrigation, with 66% and 100% of ETC treatments hardly differing from one another though consistently diverging from rainfed plants. The effect of water stress on photosynthesis was mainly dependent on diffusion resistances in response to soil moisture. Leccino showed higher instantaneous water-use efficiency than Frantoio. Crop yield increased proportionally to the amount of seasonal water volume, confirming differences between cultivars in water-use efficiency. The unsaturated/saturated and the monounsaturated/polyunsaturated fatty acid ratios of the oil also differed between cultivars, while the watering regime had minor effects. Although irrigation can modify the fatty acid profile, polyphenol contents were scarcely affected by the water supply. Irrigation to 100% of ETC in the period August–September might be advisable to achieve high-quality yields, while saving consistent amounts of water.
160. Butterfly, seedling, sapling and tree diversity and composition in a fire-affected Bornean rainforest
• date - 2006-02
• creator - CLEARY, DANIEL F. R.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01542.x
• description - Abstract:  Fire-affected forests are becoming an increasingly important component of tropical landscapes. The impact of wildfires on rainforest communities is, however, poorly understood. In this study the density, species richness and community composition of seedlings, saplings, trees and butterflies were assessed in unburned and burned forest following the 1997/98 El Niño Southern Oscillation burn event in East Kalimantan, Indonesia. More than half a year after the fires, sapling and tree densities in the burned forest were only 2.5% and 38.8%, respectively, of those in adjacent unburned forest. Rarefied species richness and Shannon's H’ were higher in unburned forest than burned forest for all groups but only significantly so for seedlings. There were no significant differences in evenness between unburned and burned forest. Matrix regression and Akaike's information criterion (AIC) revealed that the best explanatory models of similarity included both burning and the distance between sample plots indicating that both deterministic processes (related to burning) and dispersal driven stochastic processes structure post-disturbance rainforest assemblages. Burning though explained substantially more variation in seedling assemblage structure whereas distance was a more important explanatory variable for trees and butterflies. The results indicate that butterfly assemblages in burned forest were primarily derived from adjacent unburned rainforest, exceptions being species of grass-feeders such as Orsotriaena medus that are normally found in open, disturbed areas, whereas burned forest seedling assemblages were dominated by typical pioneer genera, such as various Macaranga species that were absent or rare in unburned forest. Tree assemblages in the burned forest were represented by a subset of fire-resistant species, such as Eusideroxylon zwageri and remnant dominant species from the unburned forest.
161. Respiratory System with Heart in situ, Lungs, and Bronchial Trees
162. Vegetation structure and biodiversity along the eucalypt forest to rainforest continuum on the serpentinite soil catena in a subhumid area of Central Queensland, Australia
• date - 2006-05
• creator - SPECHT, RAY L.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01628.x
• description - Abstract  The deep lateritic earths that cap the serpentinite outcrop in the Rockhampton – Marlborough area on the Tropic of Capricorn in Central Queensland have been eroded to expose the underlying ultramafic rock. Water-holding capacity of these nutrient-poor soils increases in a gradient from the skeletal soils to the deep lateritic earths and results in a continuum of structural formations from open-woodland to woodland to open-forest. A couple of closed-forest (rainforest) stands have developed where seepage into Marlborough Creek occurs throughout the year. Aerodynamic fluxes (frictional, thermal and evaporative) in the atmosphere as it flows over and through the vegetation influence the annual foliage growth in all strata in the continuum from skeletal soils to deep lateritic earths. The lateral growth of each plant is abraded so that the sum of the foliage projective covers of overstorey (FPCo) and understorey (FPCu) strata – that is Σ(FPCo + FPCu) – remains constant throughout the serpentinite soil catena. As more water becomes available in the soil catena, the mineral nutrient levels in overstorey leaves increase, making developing leaves more vulnerable to insect attack. Although the number of leaves produced annually on each vertical foliage shoot in the overstorey increases along the soil-water gradient, Σ(FPCo + FPCu) remains constant in all stands. The carbon isotope ratios (a measure of stomatal resistance) and leaf specific weights (LSWs) (a measure of the proportion of structural to cytoplasmic content in a leaf) of overstorey and understorey strata, however, are constant throughout the continuum. The well-watered rainforest pockets – where seepage occurs – form the end point of this serpentinite continuum. LSWs and carbon isotope ratios of the canopy trees are similar to those in the sheltered understorey in the eucalypt communities. A gradient of foliage attributes is observed from evergreen canopy trees (12 m) to subshrubs (2 m) in the sunlit life forms that compose the complex structure of the rainforest stands in the humid to subhumid climate of Central Queensland. As alpha diversity (number of species per hectare) is correlated with annual shoot growth per hectare, species richness along the serpentinite continuum is almost half that of nearby plant communities on medium-nutrient soils. The one to two eucalypt species per hectare are about a tenth of the number recorded on adjacent medium-nutrient soils.
163. Trees as good citizens
• date -
• creator - Pack, Charles Lathrop, 1857-1937
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
164. Trees : the yearbook of agriculture, 1949
• date -
• creator - United States. Department of Agriculture
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Includes bibliographical references and index
165. Discordance of Species Trees with Their Most Likely Gene Trees
166. How Does Water Climb a Tree?
• date - 2004-01-20T16:54:38Z
• creator -
• provider - NSDL OAI Repository
• location - compadre.org:806
• description - This resourse describes a simple lab about how water molecules are lifted in a celery stalk. It includes a discussion of the physics.
167. The Electronic Paper Chase
• date -
• creator - Steve Ditlea
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=96F1891E-A66A-47E3-BFF9-8E70AB51F25&ARTICLEID_CHAR=8794D83B-7F07-49E2-B778-E25E8F43A11
• description - It offers excellent resolution and high contrast under a wide range of viewing angles, requires no external power to retain its image, weighs little, costs less and is remarkably flexible (literally and figuratively)-unlike today's computer displays. No wonder traditional ink on paper continues to flourish in a digital world that was expected to all but do away with it.Yet ink on paper is lacking in one of the essential traits of computer displays: instantaneous erasure and reuse, millions of times without wearing out. Electronic ink on paper with this ability could usher in an era of store signs and billboards that could be updated without pulping acres of trees; of e-books that embody the familiar tactile interface of traditional books; of magazines and newspapers delivered wirelessly to thin, flexible page displays, convenient for reading, whether on crowded subways or desert islands.
168. On Cemetery Pond
• date -
• creator - Gibbs
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=4133E7B2-88DC-4E0A-8CF3-B6229770262&ARTICLEID_CHAR=B21F0F40-7F99-481C-AC42-6C3EB07F5CB
• description - Last night the first storm of winter hit northern California with sudden fierceness, its 90-mile-per-hour gusts tearing limbs from trees, its inch and a half of downpour collapsing a roof in San Rafael. It was just the kind of weather to put red-legged frogs in a romantic mood. And for that reason, it was just the dreary sort of night that could drag Gary Fellers away from leftover Thanksgiving turkey into the boot-deep muck of Cemetery Pond.Tonight the front still lingers, but it has thinned enough to allow a gibbous moon, casting colored halos through fast-moving clouds, to illuminate our short hike into the ranchland of Point Reyes National Seashore. Fellers, the park scientist, and freelance biologist Chris Corben rest binoculars atop the flashlights protruding from their lips and slowly scan the pond. Just above a green skin of algae and duckweed and just below thick stands of rushes, tiny green gems glitter in the beams. They are the eyes of the quarry.
169. Review: The World of Ag Biotech
• date -
• creator - Rick Weiss, staff editors
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=96F1891E-A66A-47E3-BFF9-8E70AB51F25&ARTICLEID_CHAR=E5F1944A-A31B-46DC-B201-0B21841068F
• description - It was 1981, and California scientist Martin Apple was showing visitors his new, futuristic enterprise: the International Plant Research Institute, one of the world's first biotechnology companies devoted to agriculture. The biotech gold rush was just getting started, and Apple, talking about his plans to revolutionize agriculture, confided enthusiastically to a New York Times reporter, "We are going to make pork chops grow on trees!""When that quote appeared in the newspaper Apple was mortified," writes Daniel Charles in Lords of the Harvest, his fascinating and thoroughly reported book about the science, business and politics of agricultural biotechnology. "He meant, of course, that engineered plants might produce the same nutrients that one finds in a pork chop, not an actual hunk of meat hanging on a tree. Besides which, as an observant Jew, he'd never touched a pork chop in his life." Apple even called the chairman of his board to see how they might get the Times to print a correction. "Don't worry about it," he told Apple. "It's great publicity."
170. Voyages: The Glass House in the Desert
• date -
• creator - Marguerite Holloway
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=AAA12C8C-CA2A-45B9-9DBB-2FCA0815FCB&ARTICLEID_CHAR=29D48F3E-543B-4434-AA7D-62E05B5D465
• description - It is a brilliant hot morning in the desert north of Tucson, Ariz., and the sun blazes down on a dozen or so people as they wend their way through a savanna and around a marsh, an ocean, and miles of pipes, channels, steel struts and glass panels. Half factory, half unkemptlooking greenhouse, the great glass structure that is Biosphere 2 is open to the public, to students and to scientists conducting climate change experiments. And on this day the rain forest, usually closed to visitors, is also open.The group moves from behind the scenes-from the concrete underbelly of a man-made mountain and its 55-foot waterfall-out into the steamy forest, walking along wooden boards, sweltering in 85 degrees Fahrenheit, 95 percent humidity. The Arizona desert is no longer visible through the tangle of sugar palms, banana and Kapok trees (the latter have to be trimmed so they don't burst through the glass ceiling), and other vegetation. William Young, a guide, explains that researchers have just finished subjecting the plants to 30 days of drought followed by seven days of rain over several months to learn how these conditions affect carbon dioxide intake. Because Biosphere 2 is a closed system, rainfall and atmospheric makeup can be regulated and measured, allowing scientists to conduct controlled experiments.
171. Adapting To Complexity
• date -
• creator - Ruthen
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=793F0104-552B-4097-A887-9D0A143E681&ARTICLEID_CHAR=34790BBC-970A-4B91-927F-B6111E53E1F
• description - In an autumn afternoon John Holland strolls among the pines and aspens that blanket, like a green and golden patchwork quilt, the mountains just north of Santa Fe, N.M. What impresses Holland about the scene is not just its beauty but also its complexity. The aspens compete with the pines for light as well as for water and nutrients from the rocky soil. As each tree grows and adapts, it alters the supply of resources available to its neighbors, and in doing so, it changes its own chances for survival.Holland and his colleagues at the Santa Fe Institute in the valley below are searching for a unified theory that would explain the dynamics of all living systems, be they groves of trees, colonies of bacteria, communities of animals or societies of people. All are systems of many agents, each of which interacts with its neighbors and, most important, can adapt to change.
172. Make Science, Not War
• date -
• creator - Musser
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8FF32714-CA1C-4025-BE8D-0FE4B5C348B&ARTICLEID_CHAR=D187944E-FF81-43EA-8E04-D2F16C2C4AA
• description - To reach the observatory, we drove past the gutted motel, climbed over the fallen lamppost and walked past the trenches. Muhamed warned me to follow in his footsteps; the area hadn't been searched for mines yet. Over the stubs of trees we could see Sarajevo stretched out below us, a lovely sight for a gunner. The observatory was littered with shiny glass from shattered telescopes, an old Nature cover, a green plastic turtle Muhamed's daughter used to play with when visiting. "Some scraps of memory," he remarked. "I worked here 20 years."Three years after the end of siege, Sarajevo is once again a fairly normal European city. But scientific research is still just a memory, and many people worry that it might always be. "Higher education never has been a priority in reconstruction efforts," says Wolfgang Benedek of the World University Service, an Austrian-based advocacy group.
173. Rethinking Green Consumerism
• date -
• creator - Jared Hardner and Richard Rice
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=7A32B6BE-71CF-4E92-8233-6E6C4F483C7&ARTICLEID_CHAR=5FC5331C-5093-4C8D-B909-6117678F0F3
• description - Over the past decade, one popular tropical conservation effort has been to encourage consumers to pay more for products that are cultivated or harvested in ecologically sensitive ways. Myriad international development projects have promoted these so-called sustainable practices in forests and farms around the world. Ordinary citizens in the U.S. and Europe participate by choosing to buy timber, coffee and other agricultural goods that are certified as having met such special standards during production. One of the best known of these certified, or "green," products is shade-grown coffee beans, which are cultivated in the shady forest understory rather than in sunny fields where all the trees have been cut down.Efforts to develop green products deserve support and praise. But in the context of the global economy, sustainable agriculture and consumer actions alone will not be enough to conserve the plants and animals that are most threatened by deforestation. We believe that a bold new approach, which we call conservation concessions, provides a potentially powerful way to expand the green market from its present dependence on products to the broader notion of green services-the opportunity to purchase biodiversity preservation directly.
174. The Earliest Zoos and Gardens
175. Diet and Primate Evolution
• date -
• creator - Milton
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=FC103ADB-0286-4433-B3C8-5C7978B981A&ARTICLEID_CHAR=685BA994-6032-48E9-86B7-42FD95E3A4E
• description - As recently as 20 years ago, the canopy of the tropical forest was regarded as an easy place for apes, monkeys and prosimians to find food. Extending an arm, it seemed, was virtually all our primate relatives had to do to acquire a ready supply of edibles in the form of leaves, flowers, fruits and other components of trees and vines. Since then, efforts to understand the reality of life for tree dwellers have helped overturn that misconception.My own field studies have provided considerable evidence that obtaining adequate nutrition in the canopy--where primates evolved--is, in fact, quite difficult. This research, combined with complementary work by others, has led to another realization as well: the strategies early primates adopted to cope with the dietary challenges of the arboreal environment profoundly influenced the evolutionary trajectory of the primate order, particularly that of the anthropoids (monkeys, apes and humans).
176. How the Immune System Develops
• date -
• creator - Weissman, Cooper
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=D1B345DF-2A82-4AA5-A14E-8FA52486CFB&ARTICLEID_CHAR=81949CEF-47D3-4BCE-A5F3-3D1E41758E0
• description - The marvelous array of deftly interacting cells that defend the body against microbial and viral invaders arises from a few precursor cells that first appear about nine weeks after conception. From that point onward, the cells of the immune system go through a continuously repeated cycle of development. The stem cells on which the immune system depends both reproduce themselves and give rise to many specialized lineages--B cells, macrophages, killer T cells, helper T cells, inflammatory T cells and others.The cells of the immune system are not isolated in a single space or arrayed in the form of a single organ; instead they exist as potentially mobile entities, unattached to other cells. This characteristic is not only crucial to their function but also confers a boon on researchers, who can isolate immune cells in relatively pure form at every stage of differentiation. Experimenters can thus determine the properties of cells and construct cellular "family trees," or lineages.
177. By the Numbers: Air Pollution in the U.S.
• date -
• creator - Doyle
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=F1E36413-4C42-4E84-BCE9-A10BEB1E9D3&ARTICLEID_CHAR=738FDDED-5355-440B-8FD2-71226E36C7B
• description - The worst air pollution disaster ever recorded was in December 1952, when a temperature inversion trapped soot, sulfur dioxide and other noxious gases over London, killing 4,000. Nothing as dramatic has ever happened in a U.S. city, nor is it likely to, thanks largely to the efforts of the Environmental Protection Agency and various state agencies. Still, it is likely that thousands of Americans die prematurely every year because of air pollution.The EPA has focused on air concentrations of six pollutants: ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, particulates (soot) and lead. (The concern here is ground-level ozone, not ozone in the stratosphere, which blocks ultraviolet rays.) The first five adversely affect lung function, exacerbating problems such as asthma. In addition, carbon monoxide, sulfur dioxide and particulates contribute to cardiovascular disease; the last also promotes lung cancer. Lead causes mental retardation in children and high blood pressure in adults. Nitrogen oxides and sulfur dioxide are the principal contributors to acid rain, and ozone damages crops and trees.
178. Can Sustainable Management Save Tropical Forests?
• date -
• creator - Rice, Gullison, Reid
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=F1E36413-4C42-4E84-BCE9-A10BEB1E9D3&ARTICLEID_CHAR=91D05C5B-5DF7-484C-B5F8-270E7925617
• description - To those of us who have dedicated careers to conserving the biodiversity and natural splendor of the earthFs woodlands, the ongoing destruction of tropical rain forest is a constant source of distress. These lush habitats shelter a rich array of flora and fauna, only a small fraction of which scientists have properly investigated. Yet deforestation in the tropics continues relentlessly and on a vast scale--driven, in part, by the widespread logging of highly prized tropical woods.In an effort to reverse this tide, many conservationists have embraced the notion of carefully regulated timber production as a compromise between strict preservation and uncontrolled exploitation. Forest management is an attractive strategy because, in theory, it reconciles the economic interests of producers with the needs of conservation. In practice, sustainable management requires both restraint in cutting trees and investment in replacing them by planting seedlings or by promoting the natural regeneration of harvested species.
179. Cave Inn
• date -
• creator - Wong
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=036819B0-B583-418A-A546-CDF5B01BD0A&ARTICLEID_CHAR=5B3695F6-01C9-4CDE-95BA-1CE766B7B41
• description - From Croatia's capital city, Zagreb, Vindija cave is about a 90-minute drive through the rolling, rugged terrain of a northwestern region known as the Hrvatsko Zagorje. Today quaint cottages dot the countryside, the dwellings of farmers who coax corn and cabbages from the rocky soil. Thousands of years ago, however, Neanderthals inhabited these hills, and I have come to visit this cave that some of them called home.The roads narrow as paleontologist Jakov Radovcic of the Croatian Natural History Museum and I approach Vindija, and the last 100 or so meters (about 330 feet) to the site have to be traversed on foot. "They chose a place near a spring," he observes, acknowledging the sound of trickling water that greets us as we step out of the car. A rock-strewn trail takes us into the woods and up a steep hill. Through the trees the landscape below is visible for a considerable distance. "The Neanderthals were trying to control the region," Radovcic remarks, adding that other Neanderthal shelters in Croatia bear similar strategic profiles: all are elevated, with a proximal water source.
180. Profile: Frederick Sanger
• date -
• creator - Ruthen
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=A02A2913-A084-4BBA-9DFC-F2ABD8F2E16&ARTICLEID_CHAR=AF37052F-BDD6-4325-93FF-A1D213B7895
• description - One might expect a two-time Nobel Prize winner to spend his days raising funds for a worldclass laboratory, giving lectures to adoring colleagues and collecting royalties on his best-selling novel. Yet Frederick Sanger seeks neither fame nor fortune. Instead the man who built the foundations of modern biochemistry lives quietly in Swaffham Bulbeck, England, tending a garden of daffodils, plum trees and herbs. "I think Sanger hasn't been recognized as much as some, partly because he is an undemonstrative person," says Alan R. Coulson, who collaborated with Sanger for 16 years at the MRC Laboratory of Molecular Biology in Cambridge.Forty years ago, Sanger was the first to reveal the complete structure of a protein. Then during the 1970s he developed one of the first techniques for reading the genetic code. "He deserved two Nobel Prizes," says biochemist G. Nigel Godson of New York University Medical Center. "He single-handedly engineered two revolutions in biology." In addition, Coulson boasts, Sanger deserves much of the credit for laying the groundwork for the Human Genome Project, the multinational effort to determine the entire sequence of nucleotides in human DNA.
181. Profile: Driven Up a Tree
• date -
• creator - Lewis
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=036819B0-B583-418A-A546-CDF5B01BD0A&ARTICLEID_CHAR=75D4E10B-EF63-4CAB-A442-79503586881
• description - Perched at the top of an oak tree, Margaret D. Lowman surveys the tips of tall palms and jungle plants and the fragment of Florida sea peeking through the foliage way below her. For her, the climb to the little platform wedged in the branches was effortless; despite the humidity, there's not a bead of sweat on her forehead. She inhales the early morning air and exudes contentment. The 45-year-old botanist later confesses that she prefers coming down to clambering up. "Man was not made to live in the trees like monkeys," she declares. It's a strange observation for Lowman to make. She's come about as close as anyone to giving monkeys some real competition.Lowman has made thousands of climbs in her quest to discover more about one of the earth's last frontiers: the rainforest canopy. The difficulty of getting up into the canopy had preserved its status as one of world's most uncharted territories-until Lowman and a handful of other highminded scientists devised various means of scaling those heights. When she's not using ropes to haul herself into the treetops, she might rely on a hot-air balloon to suspend herself over them or a crane to lower herself into them. When she was pregnant, she squeezed into a cherry picker to continue her research. Her pioneering work on ways to get into the canopy has taken her to Cameroon, Peru, Belize, Samoa, Panama and Australia and was recognized in 1997 when she was made a fellow of the venerable Explorers Club, one of 12 botanists among its 2,800 members.
182. Moroto Morass
• date -
• creator - Wong
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=2295C979-F1A0-45DA-89BE-E31CE3C5EFB&ARTICLEID_CHAR=6B110CA0-4E5A-403A-8F55-0A6ADF22B85
• description - The arid, scrub- and acacia-dotted hills of UgandaFs Moroto region in East Africa are not where youFd expect to find an ape. But more than 20 million years ago, during the Miocene epoch, this area was the woodland home of a surprisingly modern- looking ape that may have swung through the trees while its primitive contemporaries traversed branches on all fours. According to a report in the April 18 issue of Science, this ape displays the earliest evidence for a modern apelike body design--nearly six million years earlier than expected--and may belong in the line of human ancestry.The authors--Daniel L. Gebo of Northern Illinois University, Laura M. MacLatchy of the State University of New York at Stony Brook and their colleagues-- first focused on fossils found in the 1960s. The facial, dental and vertebral remains, originally dated to 14 million years, revealed a hominoid (the primate group comprising apes and humans) with a puzzling combination of features--its face and upper jaw resembled those of primitive apes, but the vertebral remains were more like modern apes. Consequently, paleontologists were at a loss to classify the Moroto hominoid definitively and tentatively placed it in various, previously established taxonomic groups.
183. Frankly, My Dear, I Don't Give A Dam
• date -
• creator - Nemecek
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=F673F13F-018C-4A5D-9339-CB8501DE3CE&ARTICLEID_CHAR=24A05FF4-1DFF-43A6-B0C0-9A4E7148BA4
• description - Perhaps more than any other ecological no-no out there, dams enrage environmental activists. Legend has it that John Muir, founder of the Sierra Club, died of a broken heart after the OFShaughnessy Dam in Yosemite National Park was built despite his groupFs protests. These activists argue that you canFt redirect millions of gallons of water--even for such worthy causes as flood control or renewable- energy projects--without having at least some deleterious effect on the local environment. But documenting long-term changes to ecosystems along rivers is complex, so such conclusions have been difficult to test.A recent study of Swedish rivers published in Science, however, has succeeded in quantifying the extent to which biodiversity can be choked off by dams. Researchers at Ume University counted different species of trees, shrubs and herbs at some 90 sites along rivers that had been dammed. Some of the Swedish dams are nearly 70 years old, which enabled the team to examine how ecosystems change over decades. In addition, the group surveyed species along pristine rivers in Sweden--hard to find in an era when the majority of rivers around the world are controlled by dams.
184. Voyages: Desert Metropolis
• date -
• creator - Gary Stix
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=6EF68F9D-077C-A71D-5AC37CEEA2A8AFD9&ARTICLEID_CHAR=6F275057-A41D-009E-24F6A872E6F682F6
• description - Before us stand the skeletons of camelthorn acacia trees that flourished before Vasco da Gama made his way around the Cape of Good Hope at the end of the 15th century. The cracked whitish basin, or pan, on which the acacias are still rooted is appropriately named Dead Vlei. On three sides, reddish-orange sand mountains rise as high as 300 meters. Our group is in the midst of Namibia's dune sea, more than a 400-kilometer drive southeast from the coastal city of Swakopmund. The Namib Desert extends in a strip 2,000 kilometers long and up to 150 kilometers wide down the southwestern African coast.The sand heaps that tower immediately over us are star dunes. The wind blowing from multiple directions gives them right-angled ridges. When viewed from an airplane or a balloon, they assume the namesake shape. If you've seen one dune, you haven't seen them all. Namib cousins of star dunes bear names like parabolic, transverse and Barchan (crescent-shaped). According to comparative dunologist Nicholas Lancaster, a research professor at the Desert Research Institute in Reno, Nev., satellite imagery reveals that the same types of dunes can be found in Saudi Arabia and southern California, in addition to Namibia.
185. One Good Pest Deserves Another
• date -
• creator - Nemecek
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=72229529-049B-40CD-A4C9-298B2565D01&ARTICLEID_CHAR=11311A62-E9EF-4B34-A797-8921DCC5BE1
• description - At the turn of the century, Floridians introduced the melaleuca tree into the Everglades, hoping it would dry out the mosquito-infested wetlands. With no enemies in the U. S., the evergreen tree from Australia thrived. Now residents are once again turning Down Under for help: this time seeking insects that eat melaleucas. Researchers at the U.S. Department of Agriculture recently announced that they have finally identified an insect they believe will not harm what is left of the Everglades.The insects had to be called in because the melaleuca did its job too well. The tree crowded out native plants, and the altered ecosystem could not support the same diversity of indigenous wildlife as the natural system. Furthermore, melaleuca forests drink four times more water than the plants they replaced, and water is in short supply in southern Florida. To slow the prolific trees, workers have hacked, sprayed and uprooted. Yet the melaleuca spreads nearly 50 acres every day.
186. Gear and Technique/No Way Up
• date -
• creator - Michael Menduno
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=BFC6A033-D305-424F-A383-DF042A56CBD&ARTICLEID_CHAR=05C1D60D-D9F6-45AE-BE50-E690607B122
• description - George Irvine and fellow explorers Jarrod Jablonski and Brent Scarabin are five kilometers from the mouth of Florida's Wakulla Springs. Trailing behind their torpedo-shaped underwater scooters, they barrel through the water-filled cave at a depth equivalent to a structure excavated 30 stories down into the earth. The watery darkness presses in around them, swallowing the beams of their 100-watt arc lamps. The recesses of the submerged limestone tunnel have not been illuminated in the millions of years since the sedimentary rock accreted from the remains of dead sea creatures.After descending for 30 meters through the clear waters of a lake to the cave entrance, the daredevil crew has motored in formation for more than two and a half hours. The gaping underwater passageway-big enough to accommodate a taxiing 747-shows no signs of narrowing as the men press on with their mission of finding the elusive source of the waters that well up to the surface, where bald cypress trees line the shore and alligators make their home.
187. The Killing Lakes
• date -
• creator - Holloway
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=86432992-17B0-4B7B-A538-C63722AEEB7&ARTICLEID_CHAR=060A4BD5-1AA9-4050-821E-F870393D55D
188. 50 and 100 Years Ago
• date -
• creator - Staff Editor
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=5BEF64B8-961B-407A-9049-2688DAA8573&ARTICLEID_CHAR=008B9A4F-4928-402B-B059-158ACD1F95C
• description - FEBRUARY 1944 If your tire treads are wearing thin and you think something should be done about it, you are dead right. And something is being done. Synthetic tires are good now, but will be excellent. After performing the astounding miracle of creating in little more than two years a totally new complex industry able to produce synthetic rubber at a rate faster than Americans have ever used the product of rubber trees, American enterprise and ingenuity are now busy with the next task: That of making synthetics so good and so cheap that we shall never wish to return to Nature's rubber again.The automatic pilot has deservedly earned a great reputation for itself. But there has always been the feeling that it would not quite do the job in very rough weather. Now Wright Field has permitted the announcement to be made of a new electronically controlled automatic pilot developed by the Minneapolis-Honeywell Company. The sensitivity of the electronic mechanism is such that it returns the plane almost immediately to its course despite cross currents, wind variations, and air blasts from exploding anti-aircraft shells.
189. Seeing the Forest for the Trees
• date -
• creator - Wright
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=17A14774-EE98-4B7D-8AF9-290B5EDDD7A&ARTICLEID_CHAR=13EDBC8E-504E-4836-85A8-0AB32F559B3
• description - As scenic overlooks go, the Wind River canopy crane doesn't really rate. Dangling from the crane's jib in a steel cage 245 feet off the ground, you can't see the jagged crater of Mount St. Helens just 40 miles to the north or the snowy pinnacle of Mount Hood to the south. You can't see the brooding basalt ramparts of the Columbia River Gorge, into which the Wind River drains. You can't even see Wind River.But you can lean out and grab the drooping crown of Western hemlock #3064, which is suffering from a nasty infection of dwarf mistletoe. And you can visit the nuthatches nesting in the broken spire of fir snag #1014. You can nab a few bald-faced hornets or sample the nutrient-rich runoff from the upper reaches of red cedars; you can monitor the gaseous effusions of the highest epiphytes or launch plumes of pink smoke and watch turbulence carry them into the gaps and canyons of treetop topography.
190. Pollution-Purging Poplars
191. Chain Letters and Evolutionary Histories
• date -
• creator - Charles H. Bennett, Ming Li and Bin Ma
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=0897F596-E16F-3ECD-5476A602ECF532AD&ARTICLEID_CHAR=08B64096-0772-4904-9D48227D5C9FAC75
• description - IN OUR HANDS ARE 33 VERSIONS OF A CHAIN LETTER, collected between 1980 and 1995, when photocopiers, but not e-mail, were in widespread use by the general public. These letters have passed from host to host, mutating and evolving. Like a gene, their average length is about 2,000 characters. Like a potent virus, the letter threatens to kill you and induces you to pass it on to your "friends and associates"-some variation of this letter has probably reached millions of people. Like an inheritable trait, it promises benefits for you and the people you pass it on to. Like genomes, chain letters undergo natural selection and sometimes parts even get transferred between coexisting "species." Unlike DNA, however, these letters are easy to read. Indeed, their readability makes them especially suitable for classroom teaching of phylogeny (evolutionary history) free from the arcana of molecular biology.The letters are an intriguing social phenomenon, but we are also interested in them because they provide a test bed for the algorithms used in molecular biology to infer phylogenetic trees from the genomes of existing organisms. We believe that if these algorithms are to be trusted, they should produce good results when applied to chain letters. Using a new algorithm that is general enough to have wide applicability to such problems, we have reconstructed the evolutionary history of our 33 letters [see illustration on page 79]. The standard methods do not work as well on these letters. Originally developed for genomes, our algorithm has also been applied to languages and used to detect plagiarism in student assignments: anything involving a sequence of symbols is grist for its mill.
192. In Focus: Burying the Problem
• date -
• creator - Schneider
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=D8B81602-23FC-4CE8-80BA-C19177D7309&ARTICLEID_CHAR=1BE409EF-2DD5-413F-A417-7BB4C93222C
• description - In December world leaders gathered in Kyoto, Japan, to grapple with the growing threat of global warming caused by the burning of fossil fuels. To combat the surge in greenhouse gases-- chiefly carbon dioxide--researchers and policymakers have called for energy conservation, taxes on carbon emissions and the swift development of renewable energy sources, such as wind and solar power. Still, with nuclear energy out of favor and no easy replacement for fossil fuels on the horizon, the rise in atmospheric carbon dioxide might appear unstoppable. But a growing number of scientists are pointing out that another means of combating greenhouse warming may be at hand, one that deals with the problem rather directly: put the carbon back where it came from, into the earth.The idea of somehow "sequestering" carbon is not new. One method is simply to grow more trees, which take carbon from the atmosphere and convert it to woody matter. Although the extent of plantings would have to be enormous, William R. Moomaw, a physical chemist at Tufts University, estimates that 10 to 15 percent of the carbon dioxide problem could be solved in this way.
193. The Mutable Brain
• date -
• creator - Marguerite Holloway
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=DD0631D8-042D-7517-4083B97F0F252EA3&ARTICLEID_CHAR=DD23A6DA-E291-4F10-5973A40549C673D7
• description - "THE BRAIN WAS CONSTRUCTED TO CHANGE," ASSERTS Michael M. Merzenich as he sits in a small conference room at the University of California at San Francisco Medical Center. The large windows to his left look out onto a hill thick with eucalyptus trees, their branches moving now this way, now that, in the morning's wind. Merzenich's observation-no longer so radical as it was when he and a handful of others put it forth in the 1980s-is that the brain does the same: it moves this way, then that, depending on how experience pushes it. This may seem an obvious idea: of course our brains revise themselves-we learn, after all. But Merzenich is talking about something bigger: this ability of the brain to reconfigure itself has more dramatic implications.It is as if the brain is a vast floodplain. One year the water might run eastward in a series of small channels; the next it might cut a river deep through the center. A year later, and a map of the floodplain looks completely different: streams are meandering to the west. It is the same with a brain, the argument goes. Change the input-be it a behavior, a mental exercise, such as calculating a tip or playing a new board game, or a physical skill-and the brain changes accordingly. Magnetic resonance imaging machines reveal the new map: different regions light up. And Merzenich and others who work in this field of neuroplasticity are not just talking about young brains, about the still developing infant or child brain, able to learn a first language and then a second in a single bound. These researchers are describing old brains, adult brains, your brain.
194. Working Elephants
• date -
• creator - Schmidt
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=96653A5A-E143-4E3C-8051-A398ED38F8E&ARTICLEID_CHAR=1D6417C7-F422-42FE-A00B-562F20429DB
• description - In the dense forests of Myanmar, men and elephants labor together to extract timber as they have done for more than 100 years. A gesture, a word, a shift in weight is all it takes for an "oozie" to direct his elephant to carry, push, pull or stack massive logs that elsewhere are manipulated by machines. If kept viable, the tradition can guarantee the survival not only of Asian elephants but also of the forests. If the tradition is lost, a magnificent species might become extinct, and some of the oldest natural forests in Asia could become monocultured tree farms.Myanmar, formerly Burma, is the last country to use elephants extensively for logging. Just two decades ago Thailand had a vigorous population of 4,000 logging elephants. But the Thai forests were clear-cut instead of being harvested sustainably, and now many of the beasts are underemployed and malnourished. Only in Myanmar has a reverence for heritage allowed some of the largest tracts of forest on the earth to flourish unspoiled. A century-old policy of harvesting selected trees and transporting the logs by teams of men and elephants has kept vast sections of forest robust and highly productive.
195. Anti Gravity: Now You See It, Now You Don't
• date -
• creator - Mirsky
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=C46F9EA9-3685-47D3-AD7C-928A8F1E921&ARTICLEID_CHAR=D8223AB1-EC0F-460E-99D1-17905725233
• description - Picture the Beatles in a boat on a river, with or without tangerine trees and marmalade skies. TheyFre chasing another boat. Assume that Rolling Stone Keith Richards is piloting that other boat, so its path is highly erratic. The Beatles pursue, turning their boat while continuously closing the distance to their prey. Hey, it could happen.Switching from Beatles to beetles reveals, however, that pursuit of prey in one corner of the insect world turns out to be far less smooth. As was first reported more than 70 years ago, hungry tiger beetles, which have compound if not kaleidoscope eyes, run as fast as they can toward a prospective live meal but then come to a screeching stop. During this time-out, the beetles reorient toward their sidestepping targets. After zeroing in again, they resume running as fast as they can. They may have to do this three or four times before catching their prey or giving up.
196. Anti Gravity: What's Wrong with This Picture?
• date -
• creator - Steve Mirsky
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8DB13CA8-2B35-221B-68BBB19319B01718&ARTICLEID_CHAR=8DD61D64-2B35-221B-640812E786D5ED87
• description - In this world, nothing is certain but death and taxonomy. Everyone is interested in death, but few of us outside of the order Strigiformes give a hoot about taxonomy. Nevertheless, people can have taxonomy-which Merriam-Webster's defines as the "orderly classification of plants and animals according to their presumed natural relationships"-thrust upon them. Just ask the mortified folks at the University of Florida.Two of Florida's major products are the fruits of Citrus sinensis trees and football. The University of Florida's football team is called the Gators, in honor of Alligator mississippiensis. Although the name might lead you to assume that the Gators would be the football team at the University of Mississippi, the gridiron gladiators-sorry, I was channeling melodramatic sportswriter Grantland Rice (Oryza sativa) for a second there-at Ole Miss are in fact the Rebels, an appellation that pays tribute to the halcyon days of yesteryear when some Homo sapiens fought for the right to own other Homo sapiens. Go figure.
197. Trends In Biological Restoration
• date -
• creator - Holloway
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=A9362308-C3A8-4DC4-AC9C-8DE25B1A481&ARTICLEID_CHAR=7BE1654F-FB5F-4B70-B615-08BA0059758
• description - They used to stretch for hundreds of miles as a tawny sea of saw grass. Metallic-looking plankton added a golden patina to the shallow, slowly moving water that flowed between hammocks of tall grasses and stands of white-barked, high-kneed cypress trees. Even now, at half their original size, the Everglades appear to stretch forever--gilded, green, punctuated by the white of an ibis or a pink roseate spoonbill. Nothing could seem more natural.Yet the most important aspect of this unique ecosystem is anything but natural. Four great gates at the northern end of Everglades National Park and 1,400 miles of canals and levees determine the quantity of water that can enter the area. Sugarcane plantations and vegetable farms to the north and east use fertilizers and pesticides that determine the quality of that same water. Demands for agriculture, urban living and flood control have made the Everglades too wet in the wet season, too dry in the dry season, too rich in nutrient phosphorus and therefore too close to extinction.
198. Evolution: A Lizard's Tale
• date -
• creator - Jonathan B. Losos
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=FF34F144-FEE8-4F66-ABCB-60DC58A1375&ARTICLEID_CHAR=996368C5-3FE1-4375-A463-E44140F2F03
• description - Anole lizards can be found everywhere on the islands of the Greater Antilles: in the tops of trees, along their trunks, down among the leaf litter, on fence posts, near flowers. They come in all forms: short, long, blue, brown, green or gray, strong jumpers, poor jumpers, big and brazen, creeping and cautious. This incredible diversity makes the anoles, members of the genus Anolis, fascinating creatures to study. For hidden in their myriad forms and dwelling places is the key to an important biological mystery: What drives a creature's evolution to take one path instead of another?Any visitor to the islands will quickly see that the kinds of anoles that occur together-that is, sympatrically-differ in the habitat they occupy. One species, for example, will be found only in the grass, another only on twigs, a third nearby on the base of tree trunks, sometimes venturing onto the ground. These three species also differ in their morphology. The grass dweller is slender with a long tail, the twig dweller is also thin but with relatively stubby legs, and the tree lizard is stocky with long legs.
199. Introduction/Our National Passion
• date -
• creator - Davidson
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8FB06272-23A8-4FF3-9229-C86EAF19071&ARTICLEID_CHAR=371198ED-84CA-4538-BCD4-0B1BBF525E3
• description - A generation ago adolescent meteorologists monitored local weather by turning milk cartons into barometers and Ping-Pong balls into anemometers. But nowadays, simply by tapping a keyboard, their successors can track weather as it happens all over the globe. The World Wide Web offers a jungle of "weather weenie" sites. Its users can stare until stupefied at weather-radar imagery from St. Louis, St. Paul or St. Cloud, satellite pictures of fog hugging the California coast or the Appalachian foothills, charts that depict dry lines and tropical maps that show a long, sinister red band. That band is the thermal signature of El Nino, now mercifully slumbering in Pacific Ocean waters (until it strikes again!). "And Hurricane Floyd probably sucked more people onto the Internet than it did palm trees and street signs into its swirling maw," joked the Los Angeles Times.The modern fascination with weather is also epitomized by tornado chasers on the Plains, politically charged conferences on climate change and the Weather Channel on cable television. In the age of CNN and MSNBC, weather disasters receive the breathless, moment-by-moment, you-are-there coverage once reserved for wars. In the comfort of our living rooms in New York City and San Diego and Dubuque, we watch live TV images from the southeastern U.S. as Hurricane Floyd pounds beach mansions into pulp. Pundits, meanwhile, exploit every atmospheric disaster-a Chicago heat wave, a California monsoon, a Northeastern blizzard-as material for debate: Is the weather changing? Are we to blame?
200. Genetically Modified Foods: Are They Safe? - Seeds of Concern
• date -
• creator - Kathryn Brown
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=27037999-BF06-44F5-BA42-95F5CD510D6&ARTICLEID_CHAR=34AD6BAC-2CFB-4203-B34B-2BF27F32C14
• description - Last year in Maine, midnight raiders hacked down more than 3,000 experimental poplar trees. And in San Diego, protesters smashed sorghum and sprayed paint over greenhouse walls. This far-flung outrage took aim at genetically modified crops. But the protests backfired: all the destroyed plants were conventionally bred. In each case, activists mistook ordinary plants for GM varieties.It's easy to understand why. In a way, GM crops-now on some 109 million acres of farmland worldwide-are invisible. You can't see, taste or touch a gene inserted into a plant or sense its effects on the environment. You can't tell, just by looking, whether pollen containing a foreign gene can poison butterflies or fertilize plants miles away. That invisibility is precisely what worries people. How, exactly, will GM crops affect the environment-and when will we notice?
201. Climate in Flux/Warming to Climate Change
• date -
• creator - Brown
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8FB06272-23A8-4FF3-9229-C86EAF19071&ARTICLEID_CHAR=3C4FBB93-A29B-4E82-BA11-1B9DCAA1974
• description - For geophysicist Gunter Weller, getting to the office is a real trip. On weekday mornings around 7 A.M., Weller gingerly backs his black Toyota SUV down the driveway and into the icy fog that shrouds Fairbanks. His car creeps, antlike, for three miles to the University of Alaska. It's not the morning darkness-or even the icy air-that puts Weller on guard. Rather it's the sudden lurches and gaping cracks that emerge from nowhere in the road-scars of the permafrost melting below the ground.Record warm temperatures are gnawing away at the masses of ice that lie beneath Alaska and other Arctic areas-and, in the process, buckling roads, tilting trees and threatening homes. Eventually much of the boreal forests that color Alaska could dissolve into wetlands, which could, in turn, become grassland. This ecosystem makeover is a dramatic show of climate change-and perhaps a distressing harbinger of things to come. "We are beginning to see the greenhouse effect-and it's not pretty," notes Weller, director of the university's Cooperative Institute for Arctic Research.
202. Captured in Amber
• date -
• creator - David A. Grimaldi
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=55E55663-2B35-221B-696E24B7391C3A23&ARTICLEID_CHAR=55F23119-2B35-221B-686CBAA9665074C7
• description - A hurricane had savaged the forest of giant Hymenaea trees along a Central American coastline. Yellow streams of resin oozed from mangled branches and gashed trunks, while insects bred in the wreckage. One termite happened to brush against the resin and stuck fast, ultimately becoming enveloped in its flow. Terpenes and other fragrant vapors from the resin penetrated the termite's tissues, replacing the water and killing bacteria.Air, along with light and heat from the sun, induced chemical reactions in the resin so that the carbon atoms in its long molecules began to link up. The chunk of hardening sap fell to the ground, one among thousands. Tides from tropical storms of a later year washed the resin fragments and rotting logs into a lagoon, where coastal sediments covered them. Twenty-five million years of subterranean pressure polymerized the resin even further, making it solid and chemically inert. Tectonic movements eventually lifted the coastline into steep mountains 3,000 feet high, to become the island of Hispaniola in the Caribbean.
203. Endpoints
• date -
• creator - Staff Editors
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=27037999-BF06-44F5-BA42-95F5CD510D6&ARTICLEID_CHAR=467FC850-73BB-4671-867A-E11CC2B251B
• description - Gregory S. Paul, freelance scientist, artist, and editor of the Scientific American Book of Dinosaurs, offers this explanation: Gigantism has been a common feature of land animals since the beginning of the Jurassic period, more than 200 million years ago. The first true giants of the land were small-headed, long-necked, sauropod dinosaurs. Toward the end of the Jurassic many sauropods reached 10 to 20 metric tons, some weighed as much as 50 metric tons, and a few may have exceeded 100 metric tons and 150 feet in length, rivaling the largest modern whales.Why do animals become gigantic? Some reasons are simple. The bigger an animal is, the safer it is from predators and the better it is able to kill prey. Antelope are easy prey for lions, hyenas and hunting dogs, but adult elephants and rhinos are nearly immune-and their young benefit from the protection of their huge parents. For herbivores, being gigantic means being taller and therefore able to access higher foliage. Giraffes and elephants can reach over 18 feet high, and elephants can use their great bulk to push over even taller trees.
204. Troubles at the Edge
• date -
• creator - Luis Miguel Ariza
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=92F4353E-8ABD-4C63-B4DB-2D231D664CD&ARTICLEID_CHAR=463CDD06-8C33-4AC8-8554-7782DB46281
• description - DONANA NATIONAL PARK, SPAIN-While driving along a sandy road on the northern part of the National Park of Donana, in southwest Spain near Seville, Francisco Palomares outlines the glaring difference between the two habitats that run on either side. To the southeast is open pastureland; closer to the fences is a scrub zone called Coto del Rey, which also abounds with cork trees and pines growing up to four meters high. Not visible is the marshland farther away, toward the east at the park's core. The diverse environments probably make Donana the richest reserve in Europe, attracting some 400 species of birds and several types of wildcats, deer and other mammals. Yet ironically, reserves such as this one may be doing more harm than good, at least on their margins. That conclusion is based on the population of the Eurasian badger (Meles meles), which has been decreasing because of poachers drawn to the reserve in search of easy pickings. In fact, in some places there are fewer badgers on the inside of the fenced-in park than on adjacent areas outside.The badgers themselves are of no interest to the poachers, who aim for red deer and other wild game abundant on the pasturelands. Those areas are the "killing fields" for the badgers, says Palomares, a biologist at the Estacion Biologica of Donana-CSIC. At night, the animals leave the safety of the scrubs to hunt on the open lands and find themselves at the mercy of hounds unleashed by the poachers during their nocturnal raids. "We have seen entire families wiped out this way in a matter of only a few months," Palomares states.
205. Rethinking Green Consumerism
• date -
• creator - Jared Hardner and Richard Rice
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=0D76404D-2B35-221B-67244C3232F55BEA&ARTICLEID_CHAR=0D7E3AA9-2B35-221B-62FBA1A6DD43DB93
• description - Over the past decade, one popular tropical conservation effort has been to encourage consumers to pay more for products that are cultivated or harvested in ecologically sensitive ways. Myriad international development projects have promoted these so-called sustainable practices in forests and farms around the world. Ordinary citizens in the U.S. and Europe participate by choosing to buy timber, coffee and other agricultural goods that are certified as having met such special standards during production. One of the best known of these certified, or "green," products is shade-grown coffee beans, which are cultivated in the shady forest understory rather than in sunny fields where all the trees have been cut down.Efforts to develop green products deserve support and praise. But in the context of the global economy, sustainable agriculture and consumer actions alone will not be enough to conserve the plants and animals that are most threatened by deforestation. We believe that a bold new approach, which we call conservation concessions, provides a potentially powerful way to expand the green market from its present dependence on products to the broader notion of green services - the opportunity to purchase biodiversity preservation directly.
206. North to Mars!
• date -
• creator - Robert Zubrin
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=4B11A937-C523-407F-B513-7ADEDF8E98D&ARTICLEID_CHAR=9A8BB115-A474-44A1-AF97-87440883699
• description - DEVON ISLAND IS A BARREN but weirdly beautiful place in the Canadian Arctic, only 1,500 kilometers from the North Pole. About 23 million years ago a meteorite struck there with the force of 100,000 hydrogen bombs, gouging out the 20-kilometer-wide Haughton Crater. The impact killed every living thing on the island and destroyed its soil, leaving a bizarre landscape of condensed powder ridges and shock-fractured stones. Because most of the island is devoid of trees, bushes and grasses, it looks and feels like an alien world. In fact, for the past four years a team of scientists from the National Aeronautics and Space Administration has been studying the island's geology to learn about Mars [see box on next page].In 1998 I founded the Mars Society, an organization dedicated to promoting the exploration of the Red Planet. Pascal Lee, the geologist who headed NASA's Devon Island team, proposed that the society build a simulated Mars base at Haughton Crater. Researchers at this station could explore Devon under many of the same conditions and constraints that would be involved in a human mission to Mars. The things we could learn from such a program would be invaluable. For example, the crew at the Devon Island station could try out equipment intended for a Mars mission, such as water-recycling systems and spacesuits, putting the gear through months of rough treatment in the field instead of merely testing it in the laboratory. While studying Devon Island's geology and microbiology, the researchers could find out how much water an active Mars exploration team would really need. They could also investigate key issues of crew psychology, such as the effects of isolation and close confinement, team dynamics and how the layout of the station would affect the astronauts' performance.
207. Sigma Chi Chimpy
• date -
• creator - Meredith F. Small
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=D5F37E9A-F804-415B-8271-C55C998E49E&ARTICLEID_CHAR=D24437BE-447A-4E78-A616-13942D08234
• description - The patrol of chimpanzees leaves early in the afternoon, silently moving through the forest in single file. After several hours, the hunters hear a troop of monkeys jumping nervously about the canopy. The chimps stop, grab one another and grin in anticipation of the feast to come. Then all hell breaks loose. The chimps shout a rallying cry and climb purposefully into the trees. The monkeys scream in alarm and mob the hunters, but to no avail. A male chimp grabs a monkey, swings it around and takes a bite. Soon, the carcass is torn apart and shared for breakfast.Chimpanzees generally subsist on fruits, but they will hunt on occasion. Since 1963, when Jane Goodall first reported on chimp hunting at Gombe Stream Reserve in Tanzania, studies across Africa have confirmed that it is a male group activity and that red colobus monkeys are the preferred prey. In the 1970s primatologist Geza Teleki suggested that hunting serves two purposes: to fulfill protein requirements and, because the meat is precious, to gain mates.
208. Smart Sensors to Network the World
209. Letters to the Editors
• date -
• creator - Staff Editor
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=AB9F2CB9-ADA7-E562-F463B0CFD31518DE&ARTICLEID_CHAR=ABA3FD9D-F341-3C3E-02E6F88B65EC4BAE
210. Essay: Sex, Death and Kefir
211. Elastic Biomolecular Machines
• date -
• creator - Urry
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=C4AEE5CE-6FFE-49D4-9BF2-5D5BC40A8CB&ARTICLEID_CHAR=C5D0157C-0F11-4A77-A798-5AF316DEBA2
• description - The motion of living organisms is an enigmatic phenomenon. It seems to come spontaneously from within, in the blink of an eye, in the twitch of a muscle, in the sudden kick of a runner, in the jerk-and-press of a weight lifter. Theirs is not the motion of the jet airplane, the rocket or the truck, which results from the explosive expansion of high-temperature gases. Nor is it externally imposed, as in the motion of sailing ships, waves or trees blowing in the wind.Every living organism represents the successful integration of many biomolecular machines that convert energy from light or raw chemical form into whatever the organism needs--motion, heat or the construction and disposal of internal structures. During the past four decades, biochemists have reverseengineered the design of the proteins that form the principal components of these machines. Most recently my colleagues and I have progressed to designing artificial models that can carry out the energy conversions that occur in living organisms. These elastic molecules can stretch or contract in response to chemical and electrical signals, or they can generate chemical outputs in response to mechanical stimulation. In theory, these molecules can convert any stimulus into any other form of energy.
212. Flooded Forests of the Amazon
• date -
• creator - Goulding
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=ED58FE4D-A3E8-4BD9-A6E5-0741CFC9347&ARTICLEID_CHAR=4B1575AD-A4F6-4330-BDBA-F3CC6477488
• description - If you fly over the rain forest that fringes the rivers of the Amazon during the rainy season, you can catch glimpses of your aircraft between the trees. The giant mirror lying below the canopy is a vast sheet of river water. For an average of six or seven months a year, the lowland rivers rise and invade the enormous floodplain areas that border them. The forest becomes inundated with as much as 10 meters of water; understory plants become completely submerged.These flooded forests, which make up about 3 percent of the total Amazon rain forest, are one of the keys to understanding the world's richest ecosystem. In the past two decades, scientists have attempted to formulate testable hypotheses to explain the incredible biological diversity found in the rain forest. Many scientists believe that in drier times, especially during periods of heavy glaciation, the area was divided into patches, or refugia, where species evolved because of the geographic isolation of gene pools. When wetter conditions returned in interglacial epochs, the new species supposedly disperse from their centers of origin into the expanding rain forest.
213. Rain Forest Crunch
• date -
• creator - Schneider
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8547879F-7FEA-443F-9FF6-943F55BD8E6&ARTICLEID_CHAR=D28E9C95-0F81-4818-8DDD-63E55239899
• description - Going up that river was like travelling back to the earliest beginnings of the world, when vegetation rioted on the earth and the big trees were kings." Joseph Conrad's evocative portrayal of the Congo would seem to apply as well to the Amazon. That river travels across the South American continent from Peru to the Atlantic Ocean, cutting through nearly four million square kilometers of undisturbed woodlands. But is the Amazon rain forest truly a primeval jungle, a steamy, green mass that has endured for millions of years? Perhaps not, according to new results from the high Andes.The current findings challenge a perception, which first emerged in the 1970s, that tropical climates remained virtually unchanged while the great ice sheets of North America and Europe waxed and waned through a series of Pleistocene ice ages. That view was based largely on a study of microscopic shells from the ocean floor. Analyses of the kinds of creatures that had thrived in tropical seas during glacial periods indicated that the earth's equatorial regions had kept close to their presentday temperatures.
214. Captured in Amber
• date -
• creator - Grimaldi
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=7C268258-8E37-492B-8F54-1EC8BAAF9B8&ARTICLEID_CHAR=4F2947A8-B240-46A2-93EB-0993B7B6AB7
• description - Ahurricane had savaged the forest of giant Hymenaea trees along a Central American coastline. Yellow streams of resin oozed from mangled branches and gashed trunks, while insects bred in the wreckage. One termite happened to brush against the resin and stuck fast, ultimately becoming enveloped in its flow. Terpenes and other fragrant vapors from the resin penetrated the termiteFs tissues, replacing the water and killing bacteria.Air, along with light and heat from the sun, induced chemical reactions in the resin, so that the carbon atoms in its long molecules began to link up. The chunk of hardening sap fell to the ground, one among thousands. Tides from tropical storms of a later year washed the resin fragments and rotting logs into a lagoon, where coastal sediments covered them. Twenty-five million years of subterranean pressure polymerized the resin even further, making it solid and chemically inert. Tectonic movements eventually lifted the coastline into steep mountains 3,000 feet high, to become the island of Hispaniola in the Caribbean.
215. Caribbean Mangrove Swamps
• date -
• creator - Rützler, Feller
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8547879F-7FEA-443F-9FF6-943F55BD8E6&ARTICLEID_CHAR=55EE46AE-801D-4C24-BDEE-16CC4DA9C81
• description - One perceives a forest of jagged, gnarled trees protruding from the surface of the sea, roots anchored in deep, black, foul-smelling mud, verdant crowns arching toward a blazing sun, the whole mass buzzing with insects. These are the first impressions a visitor develops when approaching one of the most common sights on tropical shores--a mangrove swamp. Here is where land and sea intertwine, where the line dividing ocean and continent blurs. In this setting the marine biologist and forest ecologist both must work at the extreme reaches of their disciplines.Naturalists have long struggled to de- fine, in proper ecological terms, the environment of a mangrove swamp. Is it an extreme form of coral reef or a flooded coastal forest? Compared with the tropical timberlands of some continental interiors (which can house as many as 100 species of tree on a single hectare), a mangrove forest appears puny, monotonous and depauperate. Even the relatively rich Indo-Pacific coasts boast only some 40 mangrove species along their entire length. In the Western Hemisphere only eight or so mangrove species can be found. And of this small set just three kinds of mangrove tree are truly common.
216. River of Vitriol
• date -
• creator - Ariza
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=8DB2FB44-6B4B-47AF-B46B-791A911764D&ARTICLEID_CHAR=FB5F39B5-243C-4F26-8DCF-9EDBE241933
• description - Against the dark stand of pine trees, the waters of the Rio Tinto appear even more vividly red than usual. Here, near its headwaters in southwest Spain, the strong smell of sulfur overwhelms even the fragrance of the dense forest. The crimson river--infamous for its pH of two, about that of sulfuric acid, and for its high concentration of heavy metals--seems dead, a polluted wasteland and a reminder of the ecological devastation mining can entail.Yet the remarkable Rio Tinto is hardly lifeless, as scientists have discovered in the past several years. Even in parts of the river where the pH falls below two-- and the water is painful to touch--green patches of algae and masses of filamentous fungi abound. "Each time we go there we find something new," says Ricardo Amils, director of the laboratory of applied microbiology at the Center for Molecular Biology at the Autonomous University in Madrid, who discovered the riverFs wild ecosystem in 1990. "We have now collected about 1,300 forms of life living here, including bacteria, yeast, fungi, algae and protists. But the real number is surely much higher."
217. After the Deluge
• date -
• creator - Beardsley
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=07C2E454-8DC1-46F7-BE85-4068FD11960&ARTICLEID_CHAR=A292D6EB-887E-4039-AFFB-0E3326E3E4C
• description - Anatural disaster in a study site might seem like bad news for field ecologists, but when Hurricane Lili swept over the Exuma Islands in the Bahamas on October 19, 1996, the havoc presented two researchers with a unique opportunity.David A. Spiller of the University of California at Davis and Jonathan B. Losos of Washington University had just surveyed lizard and spider populations on 19 of the small islands around Great Exuma. After recovering their boat from a clump of trees, they were able to recensus the populations over the next few days and so chart the hurricaneFs violence. Most such surveys, in contrast, are conducted weeks or months later and so can leave key questions unanswered. When animals vanish, for instance, it could be either because habitat was destroyed or because individuals were literally blown away
218. Tool Time on Cactus Hill
• date -
• creator - Beardsley
• provider - NSDL OAI Repository
• location - http://www.sciamdigital.com/browse.cfm?sequencenameCHAR=item2&methodnameCHAR=resource_getitembrowse&interfacenameCHAR=browse.cfm&ISSUEID_CHAR=95C97E8D-4E3A-4EE5-A478-944FC3A850A&ARTICLEID_CHAR=AEDE7C6C-01D5-4AE5-BE40-63219CFD1E0
• description - On a scorching Saturday in late August in southern Virginia, at the end of a dirt track leading through fields of corn and soybeans, archaeologist Michael F. Johnson sits in the shade of oak and hickory trees eating his packed lunch. Nearby, brightblue tarpaulins protect excavations that have brought Johnson here most weekends for the past several years.The object of JohnsonFs passion is a dune of blown sand known as Cactus Hill. Between bites, Johnson is debating with visiting archaeologist Stuart J. Fiedel what the place was like 14,000 years ago. It must have been ideal for a summer camp, Johnson thinks. Facing north, it would have been cooled by winds coming off glaciers hundreds of miles distant. He offers me an inverted plastic bucket to sit on. The dune would have been dry, he continues, a welcome relief from the surrounding insect-infested bogs. The Nottoway River was at the time only a stoneFs throw away. There were lots of animals: mastodon, elk, bison, deer, perhaps moose and caribou.
219. Shape of Things: Trees
220. Visiting a Recycling Plant
• date - 2006-08-24
• creator - WGBH Educational Foundation
• provider - NSDL OAI Repository
• location - http://www.teachersdomain.org/3-5/sci/ess/earthsys/recycleplant/index.html
• description - In this ZOOM video segment, cast member Francesco follows the paper trail to find out what happens to his recyclables. He visits a material recovery center and learns how paper is recycled and the number of trees that are saved as a result.
221. Visiting a Recycling Plant
• date - 2006-08-24
• creator - WGBH Educational Foundation
• provider - NSDL OAI Repository
• location - http://www.teachersdomain.org/6-8/sci/ess/earthsys/recycleplant/index.html
• description - In this ZOOM video segment, cast member Francesco follows the paper trail to find out what happens to his recyclables. He visits a material recovery center and learns how paper is recycled and the number of trees that are saved as a result.
222. Visiting a Recycling Plant
• date - 2006-08-24
• creator - WGBH Educational Foundation
• provider - NSDL OAI Repository
• location - http://www.teachersdomain.org/K-2/sci/ess/earthsys/recycleplant/index.html
• description - In this ZOOM video segment, cast member Francesco follows the paper trail to find out what happens to his recyclables. He visits a material recovery center and learns how paper is recycled and the number of trees that are saved as a result.
223. Shape of Things: Trees
224. Shape of Trees: The Frustration Principle
225. Design: Building a House
226. Visiting a Recycling Plant
• date - 2006-09-05
• creator - WGBH Educational Foundation
• provider - NSDL OAI Repository
• location - http://www.teachersdomain.org/resources/ess05/sci/ess/earthsys/recycleplant/index.html
• description - In this ZOOM video segment, cast member Francesco follows the paper trail to find out what happens to his recyclables. He visits a material recovery center and learns how paper is recycled and the number of trees that are saved as a result.
227. Design: Building a House
228. Design: Building a House
229. Design: Building a House
230. Design: Building a House
231. Design: Building a House
232. Design: Building a House
233. Design: Building a House
234. Trunk invertebrate faunas of Western Australian forests and woodlands: Seeking causes of patterns along a west-east gradient
• date - 2006-06
• creator - MAJER, J. D.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01600.x
• description - Abstract  Trunk-associated invertebrates were sampled on marri trees (Eucalyptus (Corymbia) calophylla) along a transect from Karragullen, near Perth, through to Dryandra, 150 km to the south-east. This represents a drop in annual rainfall from 1078 to 504 mm, which is accompanied by a change from jarrah (Eucalyptus marginata) forest to wandoo (Eucalyptus wandoo) woodland. Invertebrates were sampled by intercept traps, which collect invertebrates that attempt to land on the trunks, and bark traps, which collect invertebrates that move, or live, on the trunk. Trends are reported here at the ordinal level. The variety and abundance of invertebrates sampled was generally greater in the intercept than the bark traps. Invertebrate abundance, activity and biomass on bark were strongly seasonal, with greater numbers being found during the moister periods. Invertebrate abundances tended to be greater at the drier, eastern end of the transect, particularly on the three sites within wandoo woodland. These trends were analysed in terms of rainfall, soil nutrients and plant community composition. The analysis failed to detect an underlying influence of any of these factors, suggesting that the observed trends on marri trunks may be the result of invertebrate responses to the dominant tree species at the western and eastern ends of the transect, namely jarrah and wandoo respectively.
235. Comparative vegetative anatomy and systematics of the angraecoids (Vandeae, Orchidaceae) with an emphasis on the leafless habit
• date - 2006-06
• creator - BYTEBIER, BENNY
• provider - NSDL OAI Repository
• location - Botanical Journal of the Linnean Society 151(2), 165-218.
• description - The vegetative anatomy and morphology of 142 species of the angraecoid orchids (Angraecinae + Aerangidinae) and 18 species of Aeridinae were examined using light and scanning electron microscopy. Leafless members of Vandeae were of particular interest because of their unique growth habit. Leafy and leafless members of Angraecinae and Aerangidinae were examined and compared with specimens of Aeridinae. Vandeae were homogeneous in both leaf and root anatomy. A foliar hypodermis and fibre bundles were generally absent. Stegmata with spherical silica bodies were found associated with sclerenchyma and restricted to leaves in almost all specimens examined. Distinct inner tangential wall thickenings of the endovelamen occurred in several vandaceous genera. Exodermal proliferations and aeration units commonly occurred in both leafy and leafless Vandeae. Cladistic analyses of Angraecinae and Aerangidinae with members of Aeridinae and Polystachyinae as outgroups using 26 structural characters resulted in 20 000+ equally parsimonious trees. Vandeae formed the only well-supported clade in bootstrap analyses and were characterized by having a monopodial growth habit, spherical stegmata, loss of mucilage, and loss of tilosomes. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 165–218.
236. Tree Diversity, Environmental Heterogeneity, and Productivity in a Mexican Tropical Dry Forest 1
• date - 2006-07
• creator - Aguirre, Efraín
• provider - NSDL OAI Repository
• location - Biotropica 38(4), 479-491.
• description - ABSTRACT Species diversity–environmental heterogeneity (D–EH) and species diversity–productivity (D–P) relationships have seldom been analyzed simultaneously even though such analyses could help to understand the processes underlying contrasts in species diversity among sites. Here we analyzed both relationships at a local scale for a highly diverse tropical dry forest of Mexico. We posed the following questions: (1) are environmental heterogeneity and productivity related?; (2) what are the shapes of D–EH and D–P relationships?; (3) what are individual, and interactive, contributions of these two variables to the observed variance in species diversity?; and (4) are patterns affected by sample size, or by partitioning into average local diversity and spatial species turnover? All trees (diameter at breast height ≥5 cm) within twenty-six 0.2-ha transects were censused; four environmental variables associated with water availability were combined into an environmental heterogeneity index; aboveground standing biomass was used as a productivity estimator. Simple and multiple linear and nonlinear regression models were run. Environmental heterogeneity and productivity were not correlated. We found consistently positive log-linear D–EH and D–P relationships. Productivity explained a larger fraction of among-transect variance in species diversity than did environmental heterogeneity. No effects of sample size were found. Different components of diversity varied in sensitivity to environmental heterogeneity and productivity. Our results suggest that species' differentiation along water availability gradients and species exclusion at the lowest productivity (driest) sites occur simultaneously, independently, and in a scale-dependent fashion on the tree community of this forest.
237. Feeding Behavior of Purple-throated Fruitcrow (Querula purpurata: Cotingidae) in the Colombian Amazon and Its Implications for Seed Dispersal 1
• date - 2006-07
• creator - Parrado-Rosselli, Angela
• provider - NSDL OAI Repository
• location - Biotropica 38(4), 561-565.
• description - ABSTRACT We studied some feeding behaviors of the purple-throated fruitcrow (Querula purpurata) in two Colombian Amazonian forests, which affect the primary seed dispersal of the plants on which it feeds. Visit length, number of fruits removed and dispersed, feeding rates, and fruit-handling times were compared to those obtained for two other cotingas feeding on the same fruiting trees. Querula purpurata exhibited shorter visits (98 sec) and fruit-handling times (4 sec), and higher mean feeding rates (1.6 fruits/min) than Phoenicircus nigricollis and Cotinga cayana. In contrast, P. nigricollis dispersed the highest number of seeds of four of the five tree species studied. Although Q. purpurata and P. nigricollis exhibited feeding behaviors that increase seed dispersal, Q. purpurata may be more important in the transport of seeds between habitats, while P. nigricollis may be a major seed disperser within the primary forest.
238. Processes Driving Ontogenetic Succession of Galls in a Canopy Tree 1
• date - 2006-07
• creator - Fonseca, Carlos Roberto
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2006.00175.x
• description - ABSTRACT Herbivores can be associated with distinct ontogenetic stages of their host in a nonseasonal, directional, and continuous pattern of colonization and extinction of species populations called ontogenetic succession, but the processes behind this pattern are still largely unknown. We used plants of Cryptocarya aschersoniana Mez (Lauraceae) belonging to different ontogenetic stages, to examine how the density of different gall-inducing insects varies along the ontogeny of the host, and how gall density is influenced by mechanisms associated with host quality (plant height, plant shape, leaf area, specific leaf area, and hypersensitivity), and by mechanisms associated with their natural enemies (parasitoids, pathogens, and predators). In a remnant of Araucaria Forest, located in the São Francisco de Paula National Forest (Brazil), gall density (ind./100 g of leaf ) was obtained for 42 plants of C. aschersoniana divided into three height classes. Two galling species were recorded, showing quite distinct density patterns among height classes of C. aschersoniana. While Hymenoptera gall density decreased almost 50 times from small plants to canopy trees, Hemiptera gall density increased almost 10 times. Path analyses showed that Hymenoptera density was higher in smaller plants, independent of other host traits, while Hemiptera density was higher in plants exhibiting smaller leaves. Natural enemies were not detected in the Hemiptera population, and mortality rates due to predators, parasitoids, and pathogens did not affect Hymenoptera density. Processes associated with plant quality play the main role in generating the observed ontogenetic succession pattern.
239. Variation of heartrot, sapwood infection and polyphenol extractives with provenance of Acacia mangium
• date - 2006-06
• creator - B arry , K. M.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1439-0329.2006.00444.x
• description - Summary Infection of heartwood by decay fungi (heartrot) is a concern for growers of Acacia mangium for solid-wood products as the incidence can be high in some regions of Indonesia. Variation of heartrot incidence for different provenances of A. mangium was determined using two field trials in Sumatra, Indonesia. In a Riau Province trial of 21 provenances, the effect of provenance was statistically significant for natural heartrot incidence, which ranged from 1.6% to 27.2%. In a smaller trial using artificial inoculation in South Sumatra, heartwood infection incidence ranged from 39.4% to 70.8% across six provenances and both wound type and provenance were statistically significant factors. There was also significant variation in sapwood infection length related to provenance. Wood extractives (yield, total phenols, protein-precipitable tannin and 2,3-trans-3,4′,7,8-tetrahydroxyflavanone) were quantified from a subsample of trees for each trial. However, no significant differences in extractive concentration were detectable according to provenance and evidence for a relationship between heartwood extractives and heartrot incidence was generally poor. While further studies need to be completed to establish the basis for heartrot incidence, results from these trials allow for recommendations on provenance selection to reduce heartrot incidence and provide information for further genetic selection programmes.
240. Ipsilateral corticocortical projections to the primary and middle temporal visual areas of the primate cerebral cortex: area-specific variations in the morphology of connectionally identified pyramidal cells
• date - 2006-06
• creator - Elston, Guy N.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1460-9568.2006.04847.x
• description - Abstract We quantified the morphology of over 350 pyramidal neurons with identified ipsilateral corticocortical projections to the primary (V1) and middle temporal (MT) visual areas of the marmoset monkey, following intracellular injection of Lucifer Yellow into retrogradely labelled cells. Paralleling the results of studies in which randomly sampled pyramidal cells were injected, we found that the size of the basal dendritic tree of connectionally identified cells differed between cortical areas, as did the branching complexity and spine density. We found no systematic relationship between dendritic tree structure and axon target or length. Instead, the size of the basal dendritic tree increased roughly in relation to increasing distance from the occipital pole, irrespective of the length of the connection or the cortical layer in which the neurons were located. For example, cells in the second visual area had some of the smallest and least complex dendritic trees irrespective of whether they projected to V1 or MT, while those in the dorsolateral area (DL) were among the largest and most complex. We also observed that systematic differences in spine number were more marked among V1-projecting cells than MT-projecting cells. These data demonstrate that the previously documented systematic differences in pyramidal cell morphology between areas cannot simply be attributed to variable proportions of neurons projecting to different targets, in the various areas. Moreover, they suggest that mechanisms intrinsic to the area in which neurons are located are strong determinants of basal dendritic field structure.
241. The dynamic developmental localization of the full-length corticotropin-releasing factor receptor type 2 in rat cerebellum
• date - 2006-06
• creator - Gounko, Natalia V.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1460-9568.2006.04869.x
• description - Abstract Corticotropin releasing factor receptor 2 (CRF-R2) is strongly expressed in the cerebellum and plays an important role in the development of the cerebellar circuitry, particularly in the development of the dendritic trees and afferent input to Purkinje cells. However, the mechanisms responsible for the distribution and stabilization of CRF-R2 in the cerebellum are not well understood. Here, we provide the first detailed analysis of the cellular localization of the full-length form of CRF-R2 in rat cerebellum during early postnatal development. We document unique and developmentally regulated subcellular distributions of CRF-R2 in cerebellar cell types, e.g. granule cells after postnatal day 15. The presence of one or both receptor isoforms in the same cell may provide a molecular basis for distinct developmental processes. The full-length form of CRF-R2 may be involved in the regulation of the first stage of dendritic growth and at later stages in the controlling of the structural arrangement of immature cerebellar circuits and in the autoregulatory pathway of the cerebellum.
242. iversen - mahorka remixes volume two [mhrk057]
• date - 2007-10-04T00:00:00Z
• creator - iversen
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - The second offering in the series of albums of reworked mahorka audio works is contribution by TibProd's Iversen - 16 remixes, megamix of them and a bonus ringtone. Tracklist along with the original sources: 01 Xedh - El Largo Adios (Iversen Remix) Â Â Â mhrk048 va - music for elevators vol.3 02 Moscas Nekrasov - Plexo Intempestivo (Iversen Remix) Â Â Â mhrk034 moscas nekrasov - martina 2 03 Chefkirk - Forages In Pine Trees (Iversen Remix) Â Â Â mhrk033 va - music for elevators vol.2 04 Aneff - Tranz (die hard idm rmx) (Iversen Remix) Â Â Â mhrk001 aneff - tranz remixes 05 Res - Koeriski (Iversen Remix) Â Â Â mhrk015 res - lvtr ep 06 80juan80 - Aaniyksio (Iversen Remix) Â Â Â mhrk035 80juan80 - numero kaksi 07 Hard Off - Mellow (Iversen Remix) Â Â Â mhrk020 hard off - 5 grogs 08 Ikipr - Nomad Looking Over The Horizon... (Ivesen Remix) Â Â Â mhrk049 ikipr - perfected vision 09 Mono-drone and Iversen - Collabtrack 01 (Iversen Remix) Â Â Â mhrk048 va - music for elevators vol.3 10 Ivan Bachev - Echodistofon Captures (Iversen Remix) Â Â Â mhrk019 ivan bachev - echodistofon captures 16-25.05.04 11 Yourai - Pavy (Iversen Remix) Â Â Â mhrk043 yourai - unicorn's peacock ep 12 Skylined - One Happy Duck (Iversen Remix) Â Â Â mhrk010 skylined - one happy duck 13 Carl Kruger - For A Moment He Is A Gothic Building (Iversen Remix) Â Â Â mhrk032 carl kruger - karol jozef wojtyla 14 Baba Llaga - Cuarto Milenio (Iversen Remix) Â Â Â mhrk041 baba llaga - el ultimo viaje de vasilissa 15 Tusuri - Unliberum Arbitrium (Iversen Remix) Â Â Â mhrk039 tusuri - queriac 16 Helmeticronaut - Mongo Strupesang (Iversen Remix) Â Â Â mhrk028 helmeticronaut - untelling a story 17 Skylined - One Happy Duck (Bonus Ringtone by Iversen) Â Â Â mhrk010 skylined - one happy duck 18 Megamix Cover by Ivo Petrov. Mahorka, 2007
243. 1936: Reel 1: Mexico
• date - 1936-00-00T00:00:00Z
• creator - Watson Kintner
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - "S.S. Scanpenn leaves New York for Caribbean Cruise, January 24-February 18, 1936.â( title.) Cruise map. Donkey cart. Buildings: shingle, brick. Boats. Cattle in a field. Wooden shack. Tin shack. Straw shack. Surf on rocky coast. Family: boy with tiny ukulele. Old fort, surrounding hills. Circular stone structure with tin roof: storage( ? ). Street scenes: shuttered windows. Fruit or nut in tree; bananas; flowers. -, House: niche for vases in outside wall. Various scenes. Design scratched in stone. Houses along a street. Horses and carts. Ramps over street excavation. People. Oxcart with very large wheels. Street scenes: people. "Entering port at Martinique, a possession of Franceâ Houses and boats along the docks. Street scenes; distant scenery. "Martinique. Ruins of St. Pierre From Eruption of Mont Pele. 1902!â(Title.) Ruins. Arched bridge; outside oven (?).Statue of a woman. Stone wall along river or bay. Boats. Houses decorated with flags. Workmen inside ribs of unfinished boat. People. Trees.
244. 1936: Reel 4: Mexico
• date - 1936-00-00T00:00:00Z
• creator - Watson Kintner
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Carriage. Fields. House. Uniformed man on horse. Turkeys. Windmill: brick or stone. Ruins (?) Hovels (?). Houses in town: window balconies. Fleet of row boats at dock. People, traffic. Foliage; children doing step-drill. Thatch-roofed houses on stilts, [interesting) People washing clothes in river. Old man in fez holding a parrot. Snake on ground. Trees, blossoms, flowers. Market: covered stalls. Man with bicycle. Scenes of bay. Boats. Bayshore or river shore: view from water. Town. Rude housing. Canoes on river. "Djuka or bush Negroes descendants of runaway African slaves. Maintain authentic African jungle existence. Note the blue beads." [title] Negro village: woman with baby. Grass hut. People. Suckling baby. Thatched V-shaped shelter. Board and thatch house. A couple holding hands. General scenes of village life, houses.
245. Expression of OePIP2.1 aquaporin gene and water relations of Olea europaea twigs during drought stress and recovery
• date - 2007-04
• creator - Schubert, A.
• provider - NSDL OAI Repository
• location - Annals of Applied Biology 150(2), 163-167.
• description - Abstract To investigate the effects of drought and recovery on the transcript level of OePIP2.1 (a PIP2 aquaporin gene) in twigs, 2-year-old olive trees were subjected to a drought/rewatering treatment (the irrigation was suspended for a period of 4 weeks and restored for the following 4 weeks). Twig water potential, twig hydraulic resistance and incidence of embolisation in the twig were measured in parallel with gene expression under both drought stress and the following recovery. During drought, a decrease in twig water potential, an increase in twig hydraulic resistance and an increase in the extent of xylem vessel embolisation was observed in parallel with a decrease of aquaporin gene expression. Opposite trends were recorded during rewetting. A speculation on a possible contribution of OePIP2.1 aquaporin to modulate shoot embolism during drought and recovery is proposed.
246. Survivorship of seedlings of false sandalwood (Myoporum platycarpum) in the chenopod rangelands grazed by sheep, kangaroos and rabbits at Whyalla, South Australia
• date - 2006-05
• creator - TIVER, FLEUR
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01566.x
• description - ABSTRACT  Myoporum platycarpum R. Br. (Myoporaceae) is widely distributed through semi-arid New South Wales, South Australia, Western Australia and Victoria, where it occurs as an upper-storey dominant or co-dominant tree over chenopod shrublands. Previous studies have concluded that the seedlings and juveniles of many shrubs and trees, including M. platycarpum, are selectively grazed by sheep and rabbits, which threatens their long-term survival in rangelands. The aim of this study was to assess the survivorship of M. platycarpum seedlings grazed by sheep and rabbits in a rangeland setting. Seedlings of M. platycarpum were raised in the greenhouse and planted in the field and individually fenced to allow or prevent access by various herbivores. Over 1 year, the frequency of grazing and size of canopy was recorded. A flexible mixed model incorporating cubic smoothing splines was used to describe the relationship between change in canopy volume over time, fixed effects (exclosure type, time, rainfall and egesta weights) and random variability among plants, replicates and sites. The mixed models showed that there were no significant differences in canopy volume over time between sheep and rabbit-proof exclosures, indicating that rabbits were not significantly affecting the seedlings, browsing only five of those available to them, of which three survived. Large herbivores (sheep and/or kangaroos) grazed un-caged seedlings, resulting in significantly smaller canopy volumes, and higher death rates (80%). Although supplementary irrigation was applied, background losses due to desiccation in caged seedlings were up to 50%.
247. Testing the resource-matching hypothesis in the mast seeding tree Nothofagus truncata (Fagaceae)
• date - 2006-05
• creator - MONKS, ADRIAN
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01565.x
• description - Abstract:  The genus Nothofagus in New Zealand and Australia exhibits strong mast seeding (i.e. highly variable seed crops between years). Seed crop variation is synchronized within and between species over large spatial scales, and results in greatly increased wind pollination efficiency which could provide a selective benefit favouring the maintenance of mast seeding. However, the null hypothesis (that plants simply match their reproductive effort to the variable resources available each year) has not been tested in Nothofagus. Here we use a 33-year dataset on seedfall and wood ring increments for 19 individual Nothofagus truncata trees at Orongorongo, New Zealand, to test for the presence of switching (exaggeration of seedfall variability by diverting resources into, then out of, reproduction). A generalized least squares model explained 40.7% of the variance in standardized ring widths, using six weather variables (absolute minimum temperatures in March (lag 0) April (lag 0 and lag 1), May (lag 0) and rainfall in November and February (lag 0) ) and seedfall. Seedfall had a negative relationship with the current year's ring widths even after controlling for all significant weather variables. This shows that switching is occurring in N. truncata within individuals among years, and therefore that masting in this species is the result of selective forces such as increased wind pollination efficiency. As this result has been demonstrated for very few masting species, we call for this test to be applied more widely.
248. High Nothofagusﬂower consumption and pollen emptying in the southern South American austral parakeet (Enicognathus ferrugineus)
• date - 2006-09
• creator - DÍAZ, SOLEDAD
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2006.01637.x
• description - Abstract  We describe extraordinary aspects of the feeding ecology of the austral parakeet, Enicognathus ferrugineus– the most southerly distributed psittacid in the world – that allow this endemic species to inhabit and become a common bird in relatively species-poor temperate and subantarctic Nothofagus forests of South America. We used two sources of information to analyse temporal and spatial dietary changes of austral parakeets in subalpine forests near Lake Distric of southern Argentina: (i) relative abundance of parakeet foraging on the forest ﬂoor along an altitudinal transect from 1000 to 1420 m; and (ii) faeces analyses of seasonal collections. Austral parakeets largely relied on a protein-rich pollen-based spring–early summer diet by destructively harvesting large quantities of wind-pollinated Nothofagus pumilioﬂowers and efficiently emptying pollen grains – specializations previously described only in pollinating nectarivorous vertebrates. Pollen emptying rates (c. 65%) were the highest reported for psittacids and among the highest for vertebrates in general. Parakeets made extended use of short-lived N. pumilioﬂowers by tracking the altitudinal shifts in ﬂowering phenology. Additionally, parakeets complemented their diet with carbohydrates from N. pumilio insect exudates. By late summer, parakeets switched to a lipid-rich diet based on N. pumilio seeds. This resource remained available through mid-autumn because parakeets also followed in altitude the phenological delays in fruiting. In winter, parakeets fed on N. pumilio parasitic Misodendrum mistletoe buds and leaves and Cyttaria sp. parasitic canopy fungi. These results suggest that stringent food availability in these relatively high latitudes may have led to behavioural and physiological specializations of austral parakeets to obtain year-round food resources efficiently from Nothofagus trees.
249. Variation in wood density, wood water content, stem growth and mortality among twenty-seven tree species in a tropical rainforest on Borneo Island
• date - 2007-04
• creator - OSUNKOYA, OLUSEGUN O.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01678.x
• description - Abstract  Interspecific variation among wood density (WD), wood water content (WWC), tree mortality and diameter at breast height (d.b.h.) increment was examined for 27 tree species (from 13 families), based on a 9-year interval data obtained from a permanent 1-ha forest plot setup for long-term studies of tree dynamics in Kuala Belong rainforest, Brunei, on Borneo Island. The species were also categorized into three adult stature groups of understorey (maximum height ≤15–20 m tall, n = 14), midcanopy (maximum height, 20–30 m tall, n = 8) and canopy/emergent (>maximum height, >30 m tall, n = 5) tree species. All measured traits varied appreciably among species. Tree WD varied between 0.3 and 0.8 g cm−3, and exhibited the least coefficient of variation (14.7%). D.b.h. increment was low, averaging 1.05 (95% confidence limits: 0.57–2.13) mm year−1 and was attributed to predominance of understorey species in the sampled plot. Overall, annual mortality was also low, averaging 2.73% per year. The three adult stature groups differed significantly in d.b.h. increment and WWC but not in tree mortality and WD. Across species and especially more so when phylogenetic effect is minimized, WD was negatively related to tree mortality and d.b.h. increment, while a positive trend was observed between d.b.h. increment and tree mortality. A negative trend was also detected between maximum plant height and WWC, which was interpreted as a consequence of increased evaporative demand and use of xylem stored water by taller trees in order to compensate for hydraulic limitations to water transport induced by frictional resistance. No doubt, the traits chosen may vary spatially, but the consistent interspecific patterns observed in this study among coexisting species of differing adult stature reflect ‘vertical’ niche differentiation and may help to explain population regulation in a multispecies ecosystem like tropical rainforest.
250. Viability of ecological processes in small Afromontane forest patches in South Africa
• date - 2007-05
• creator - KOTZE, D. JOHAN
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01694.x
• description - Abstract  The conservation of biodiversity is dependent on protecting ecosystem-level processes. We investigated the effects of fragment size and habitat edge on the relative functioning of three ecological processes – decomposition, predation and regeneration of trees – in small Afromontane forests in KwaZulu-Natal, South Africa. Ten sampling stations were placed in each of four forest categories: the interior of three large indigenous forest fragments (100 m from the edge), the edges of these large fragments, 10 small indigenous fragments (<1 ha) and 10 small exotic woodlands (<0.5 ha). Fragment size and edge effects did not affect the abundance of the amphipod Talitriator africana, a litter decomposer, and overall dung beetle abundance and species richness significantly. Bird egg predation was marginally greater at large patch edges compared with the other forest categories, while seed predation did not differ among forest categories. Tree seedling assemblage composition did not differ significantly among large patch interiors and edges, and small indigenous fragments. Sapling and canopy assemblage composition each differed significantly among these three indigenous forest categories. Thus, while tree recruitment was not negatively affected by patch size or distance from the edge, conditions in small fragments and at edges appear to affect the composition of advanced tree regeneration. These ecological processes in Afromontane forests appear to be resilient to fragmentation effects. We speculate that this is because the organisms in these forests have evolved under fragmented conditions. Repeated extreme changes in climate and vegetation over the Pleistocene have acted as significant distribution and ecological extinction filters on these southern hemisphere forest biota, resulting in fauna and flora that are potentially resilient to contemporary fragmentation effects. We argue that because small patches and habitat edges appear to be ecologically viable they should be included in future conservation decisions.
251. Habitat selection of feral cats (Felis catus) on a temperate, forested island
• date - 2007-05
• creator - HARPER, GRANT A.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01696.x
• description - Abstract  Habitat selection of mammalian predators is known to be influenced by availability and distribution of prey. The habitat selection of feral cats on Stewart Island, southern New Zealand, was investigated using telemetry of radio-tagged cats. Compositional analysis of the habitat selection of radio-tagged cats showed they were using the available habitats non-randomly. Feral cats avoided subalpine shrubland and preferentially selected podocarp-broadleaf forest. The avoidance of subalpine shrubland by cats was probably due to a combination of the presence of a large aggressive prey species, Norway rats Rattus norvegicus, and the lack of rain-impervious shelter there. Most cats also used subalpine shrubland more often in dry weather than in wet weather. Cats did not preferentially select all the other habitats with only smaller rat species, Rattus rattus and Rattus exulans, present however. Cats were probably further influenced by the availability of large trees, in podocarp-broadleaf forest, that can provide shelter. Cats were also more active in dry rather than wet weather which supports this conclusion. Home ranges of feral cats on Stewart Island were some of the largest recorded, probably because of limited primary and alternative prey.
252. Determinants of savanna vegetation structure: Insights from Colophospermum mopane
• date - 2007-06
• creator - HEMPSON, GARETH P.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1442-9993.2007.01712.x
• description - Abstract  Savannas are structurally heterogeneous at the local, community-level scale due to fine-scale floristic heterogeneity as well as the responses of individual species to underlying environmental variation. The structure of mopane woodland, an arid savanna of southern Africa, is dictated largely by local variation in the relative dominance of tall, single-stemmed and shorter, multi-stemmed forms of the dominant tree species, Colophospermum mopane (Kirk ex Benth) Léonhard. Here we evaluate the hypothesis that the existence of these alternative forms of C. mopane, as well as the factors that dictate their distribution at a local scale, are driven by fine-scale environmental variability in available water. We surveyed trees at four sites in the Kruger National Park of South Africa, in each instance surveying both forms of the species, from both riparian and non-riparian zones. A survey of genetic variation across our sample (n = 80 individuals), using inter-simple sequence repeat (ISSR) amplification profiles, indicates that the two forms are not genetically distinct, instead being environmentally determined. While measurements of xylem pressure potentials, determined using a Scholander pressure chamber, show a significant difference between riparian and non-riparian zones, there is no significant difference between the two growth forms. Although this seems paradoxical in view of the prevalence of tree and shrub form mopane at riparian and non-riparian sites, respectively, we speculate that such a pattern may emerge through the interaction of moisture stress and top-down controls, such as those imposed by large mammal browsing and fire.
253. Monitoring the European pine sawfly with pheromone traps in maturing Scots pine stands
• date - 2006-01
• creator - Lyytikäinen-Saarenmaa, Päivi
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1461-9555.2006.00275.x
• description - Abstract  1 During 1989–93, field studies were conducted in Finland to develop a method based on pheromone traps to monitor and forecast population levels of the European pine sawfly (Neodiprion sertifer Geoffr.) and tree defoliation. 2 Three traps per site were baited with 100 µg of the N. sertifer sex pheromone, the acetate ester of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol), in maturing pine stands in southern and central Finland. In addition, three different dosages (1, 10 and 100 µg) of the pheromone were tested in 1991–92. 3 The highest number of males was observed in traps baited with the highest dose. On average, there was a 10-fold increase in trap catch between lure doses. 4 Density of overwintering eggs was used to evaluate the effectiveness of pheromone traps in predicting sawfly populations. The proportion of healthy overwintering eggs was determined each year. A model based on the number of current shoots on sample trees, diameter at breast height and tree height was formulated to estimate eggs per hectare. 5 Linear regression analysis produced high coefficients of determination between number of males in traps and density of total eggs in the subsequent generation, when populations were at peak densities. The relationships were not significant for low population densities. The results indicate a risk of moderate defoliation when the seasonal trap catch is 800–1000 males per trap or higher.
254. Mathematical optimisation of drainage and economic land use for target water and salt yields *
• date - 2006-09
• creator - Nordblom, Tom
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1467-8489.2006.00356.x
• description - Land managers in upper catchments are being asked to make expensive changes in land use, such as by planting trees, to attain environmental service targets, including reduced salt loads in rivers, to meet needs of downstream towns, farms and natural habitats. End-of-valley targets for salt loads have sometimes been set without a quantitative model of cause and effect regarding impacts on water yields, economic efficiency or distribution of costs and benefits among stakeholders. This paper presents a method for calculating a ‘menu’ of technically feasible options for changes from current to future mean water yields and salt loads from upstream catchments having local groundwater flow systems, and the land-use changes to attain each of these options at minimum cost. It sets the economic stage for upstream landholders to negotiate with downstream parties future water-yield and salt-load targets, on the basis of what it will cost to supply these ecosystem services.
255. Hermit crabs, humans and Mozambique mangroves
• date - 2001-09
• creator - Barnes, David K. A.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1046/j.1365-2028.2001.00304.x
• description - Abstract There is a complex interrelationship between upper shore hermit crabs (such as Coenobita sp. and Clibanarius sp.), coastal human populations and mangrove forests in Mozambique. The abundance, activity, shell selection and behaviour of three species of hermit crab are related to the level of mangrove cover. With increased density of mangrove trees, the study species of hermit crab changed in abundance, tended to become diurnal, spent more time feeding and were clustered in larger groups when doing so, and selected longer spired shells. All five of the same variables are also linked to the proximity and activity of humans through both direct and indirect actions. Direct effects included a tendency to nocturnal activity with proximity to human activity; indirect effects included increased and more clumped food supplies, and shell middens from intertidal harvesting and deforestation. Mangroves are important to local human populations as well as to hermit crabs, for a wide variety of (similar) reasons. Mangroves provide storm shelter, fisheries and fishery nursery grounds for adjacent human settlements, but they also harbour mosquito populations and their removal provides valuable building materials and fuel. Hermit crabs may be useful (indirectly) to coastal human populations by being a source of food to certain commercial species, and by quickly consuming rotting/discarded food and faeces (thereby reducing disease and pests). They can also cause minor problems to coastal human populations because they use shells of (fisheries) target mollusc species and can be more abundant than the living molluscs, thereby slowing down effective hand collection through confusion over identification. The mixture of positive and negative attributes that the three groups impart to each other in the Quirimba Archipelago, northern Mozambique, is discussed.
256. The role of salinity and sodicity in the dieback of Acacia xanthophloea in Ngorongoro Caldera, Tanzania
• date - 2006-03
• creator - Mills, A. J.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2028.2006.00616.x
• description - Abstract Dieback of Acacia xanthophloea (Benth.) has opened up the once densely forested Lerai area in Ngorongoro Caldera, Tanzania. Soil samples were taken from profiles in the Ngorongoro Conservation Area and Lake Manyara National Park at sites of dieback and at sites with healthy A. xanthophloea trees. Dieback sites had significantly greater electrical conductivity (EC), water-soluble Na+, K+, Cl−, SO and sodium adsorption ratios (SAR) than healthy sites. The following mean values were recorded: EC (179 versus 70 mS m−1; P < 0.001, Student's t-test, n = 8 and 10, respectively; 40–60 cm); Na+ (99 versus 30 mmolc kg−1, P < 0.001, n = 7 and 8 respectively); K+ (11 versus 3 mmolc kg−1, P < 0.05); Cl− (36 versus 7 mmolc kg−1, P < 0.01); SO (31 versus 5 mmolc kg−1, P < 0.01); and SAR (28 versus 8 mmol l−1/2, P < 0.01). Water-soluble Na+, Cl− and SO concentrations in the Lerai profiles have probably resulted in toxicity and osmotic stress which contributed to dieback. Accumulation of salts may have occurred because of reduced flow of freshwater through Lerai and/or flow of water from Lake Magadi into Lerai. Forest recovery may be possible if salinity is reduced. Management strategies for reducing salinity have been implemented and included re-establishing streams that flow through Lerai. Exclusion of elephants (Loxodonta africana) from Lerai is another management strategy presently under consideration.
257. Characteristic of natural regeneration of Aucoumea klaineana (Pierre) in Mayombe rain forest, southern Congo
• date - 2007-06
• creator - Pangou, Serge Valentin
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2028.2006.00690.x
• description - Abstract This paper presents the analysis of ten natural regenerated stands of Aucoumea klaineana in native monodominant Aucoumea forest located in the Mayombe rain forest (southern Congo). The mean total density was 0.51 ± 0.15 m−2, the main crop density accounted for 46.12% of the total density, the stocking ranged from 18.02% to 78.10% and the spatial pattern was clumped in all stands. The natural regeneration showed a nearly continuous age distribution. The difference of height between consecutive age-classes indicates a high stability of the seedlings height positions. The upper stratum generally corresponds to the oldest seedling, some new individuals had established during late stages of the regeneration phase. Analysis of the saturated models suggested a different pattern in soils with sand content above and below 80%. The model developed showed a positive correlation between the establishment of successful seedlings and soil preparation, and predicts an increase in the number of main crop seedlings from 0.03 to 1.30 seedlings m−2 when soil preparation is made. On the contrary, grasses cover and mean height of hardwood species were negatively correlated with the density of main crop seedlings. Grasses, hardwood and Cecropiaceae species competition were the main factors that explained total density but only in soils with low sand content. Thus, vegetation-control treatments in regeneration areas are highly recommended. In precommercial thinning, the height position of tree could be used as an important criterion in the selection of the remaining trees.
258. Joke: Weighing Trees
259. Free Software
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://forum.johnson.cornell.edu/faculty/mcclain/Software/Software.htm
• description - This collection of macros for Microsoft Excel addresses numerous topics like decision trees, the Central Limit Theorem, queueing, critical path analysis, regression with prediction intervals, and recognizing departures from normality.
260. Multivariate Statistics
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://149.170.199.144/multivar/intro.htm
• description - This course from Manchester Metropolitan University covers many topics in Multivariate Statistics in depth. To navigate, use the buttons at the top of the page. CA = Cluster Analysis; PCA = Principal Components Analysis; C&RT = Decision and Regression Trees; DA = Discriminant Analysis; MR = Multiple Regression. Topics under "Others" include Artificial Neural Networks, Principal Coordinates Analysis, Correspondence Analysis, Canonical Correspondence Analysis, Logistic Regression, Log-Linear Models, Mantel Test. A glossary is also included.
261. Contingency Table Calculator
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.physics.csbsju.edu/stats/contingency.html
• description - This page introduces contigency tables with an example on fruit trees and fire blight. Two calculators are provided that allow users to enter their own contigency table and test for treatment effects. The first calculator performs Fisher's Exact Test on a 2x2 tables. The second performs a chi-square test on up to a 9x9 table.
262. Classification and Regression Trees
263. Statistics Assignments
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.lhs.logan.k12.ut.us/~jsmart/stat-ch4.htm
• description - This is a collection of worksheets and activities in combination with worksheets. Topics in probability address notation, estimating, conditional probability, complements and probability trees, multiplication rule and dependency, addition rule, combinations/permutations, and expected means.
264. How an Aggressive Weedy Invader Displaces Native Trees
265. Seed Dispersal and Spatial Pattern in Tropical Trees
• date - 2006-11
• creator -
• provider - NSDL OAI Repository
• location - http://dx.doi.org/10.1371%2Fjournal.pbio.0040344
• description - The analysis of hundreds of tropical tree and shrub species reveals how different modes of seed dispersal affect the spatial clustering of these species and provides insight into the structure of these forest communities.
266. The Seeds of Diversity: Lessons from Tropical Trees
267. Are Autumn Foliage Colors Red Signals to Aphids?
• date - 2007-08
• creator -
• provider - NSDL OAI Repository
• location - http://dx.doi.org/10.1371%2Fjournal.pbio.0050187
• description - Why do plants change color in the autumn? Could it be a signal to aphids, warning them of the defensive strength of the trees, or might the cause be more mundane?
268. Genome Trees from Conservation Profiles
269. Measures of Clade Confidence Do Not Correlate with Accuracy of Phylogenetic Trees
270. SimulFold: Simultaneously Inferring RNA Structures Including Pseudoknots, Alignments, and Trees Using a Bayesian MCMC Framework
271. Retraction: Measures of Clade Confidence Do Not Correlate with Accuracy of Phylogenetic Trees
272. Widespread Discordance of Gene Trees with Species Tree in Drosophila: Evidence for Incomplete Lineage Sorting
273. Thai marine fungal diversity
• date - 2006
• creator - Rattaket Choeyklin
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2006&volume=28&issue=4&spage=687
• description - The marine fungal diversity of Thailand was investigated and 116 Ascomycota, 3 Basidiomycota, 28 anamorphic fungi, 7 Stramenopiles recorded, with 30 tentatively identified. These species have primarily been collected from driftwood and attached decayed wood of mangrove trees. The holotype number of 15 taxa is from Thailand and 33 are new records from the country.
274. Tentative standard concentration values of iron, manganese, zinc, copper and boron in Longkong (Aglaia dookkoo Griff.) Leaf
• date - 2007
• creator - Sukmee, K.
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2007&volume=29&issue=2&spage=287
• description - The standard concentration values are important for evaluation of plant nutrient status, classified into low, sufficient and high, which leads to the optimum nutrient management. However, the standardconcentration values of iron (Fe), manganese (Mn), zinc (Zn), copper (Cu) and boron (B) in longkong leaf (Aglaia dookkoo Griff.) have not been reported even though micronutrient deficiency symptom in someorchards was found. The objective of this research was to establish standard concentration values of Fe, Mn, Zn, Cu and B in longkong leaf. The leaf sampling was collected from middle leaflet of the 2nd compound leaf(5-month-old leaf) at the post harvest stage during 2003-2005 from 7 orchards in Songkhla province and 3 orchards in Narathiwat province, 10 trees per orchard. Yield of individual tree was recorded and used for establishment of nutrient standard concentration values by the high-yield-tree method (>70 kg tree-1) and theboundary-line method. The results revealed that the sufficient ranges of Fe, Mn, Zn, Cu and B established by high-yield-tree method were 74-88, 81-107, 16-19, 7-9 and 32-38 mg kg-1, respectively and the sufficientranges of Fe, Mn, Zn, Cu and B estimated by boundary-line method were 61-66, 49-58, 18-20, 7-8 and 27-30 mg kg-1, respectively. The standard concentration values by the high-yield-tree method were higher thanthose of the boundary-line method. However, the values estimated by the boundary-line method, which was calculated from the linear regression of yield and individual nutrient, did not include nutrient luxuryconsumption, and the values from this method can classify nutrients into deficient, low, sufficient and excess ranges. Therefore, the nutrient standard concentration values estimated by the boundary-line methodshould be used as the standard values for evaluation of Fe, Mn, Zn, Cu and B in longkong leaf.
275. Fruit splitting occurrence of Shogun mandarin (Citrus reticulata Blanco cv. Shogun) in southern Thailand and alleviation by calcium and boron sprays
• date - 2005
• creator - Sdoodee, S.
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2005&volume=27&issue=4&spage=719
• description - Fruit splitting is a serious problem of Shogun mandarin in southern Thailand. To alleviate this impact, the applications of calcium and boron by spraying were investigated. An experiment was established in a farmer orchard (at Amphur Sadao, Songkhla province) where four-year plants were grown at 6 m x 6 m spacing. The experiment was arranged as a completely randomized design, and 16 trees were used. There were 4 treatments (1. control or water spray, 2. 1% CaCl2 spray or C treatment, 3. 0.8% boric acid spray or B treatment and 4. 1% CaCl2+ 0.8% boric acid spray or C+B treatment) with 4 replicates. The application was started at 4 months after fruit-setting, the sprays were done at 1 month intervals. It was found that the occurrence of fruit-splitting started at 3 months after fruit-setting, and there were 4 causes of fruit-splitting: 1. scab (28.33%), 2. sun scald (11.11%), 3. sun burn (7.78%) and 4. no primary peel damage (52.78%). Various patterns of fruit splitting were found: vertical, horizontal, oblique and informal shape. The treatments of calcium and boron sprays did not affect on fruit growth or fruit size compared with the control, but they significantly enhanced fruit firmness, total soluble solid (TSS) and total acidity (TA). The treatments of C, B, and C + B can reduce the percentages of fruit splitting to 5.56, 8.89 and 6.67%, respectively, and they were significantly different from that of the control (52.22%). It is suggested that calcium and boron sprays can alleviate fruit splitting in Shogun mandarin, and fruit quality is also enhanced.
276. On UWB beamforming
• date - 2004
• creator - T. Kaiser
• provider - NSDL OAI Repository
• description - Ultra-Wideband (UWB) communication systems and Multi-Input-Multi-Output (MIMO) techniques rank among the few emerging key technologies in wireless communications. For that reason the marriage of these two complementary approaches should deserve attention. Apparently, the extremely large ultra-wide bandwidth creates rich multipath diversity which calls, at a first glance, additional antenna elements into question. However, another point of view is as follows. The attenuation by solid materials usually increases with increasing frequency; e.g. frequencies above, say, 10 GHz are considered to be blocked by walls etc. Since UWB can occupy more than 7 GHz of bandwidth (according to FCC regularisation) the performance of a communication link can be physically extended only by adding spatial information, i.e. multiple antennas, even if such extension may play a minor role. From this point of view UWB& MIMO presents an upper physical bound for indoor communications and is therefore at least worth to be investigated. In order to see the forest for the trees, we will focus in this limited contribution on beamforming among all alternative MIMO techniques (like space time coding or spatial multiplexing).
277. Evaluation of nitrogen status and total chlorophyll in longkong (Aglaia dookkoo Griff.) leaves under water stress using a chlorophyll meter
• date - 2005
• creator - Kaewkong, P.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27-4-pdf/06-longkong.pdf
278. Composition of canopy ants (Hymenoptera: Formicidae) at Ton Nga Chang Wildlife Sanctuary, Songkhla Province, Thailand
• date - 2005
• creator - Decha Wiwatwitaya
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27_openweek_suppl3_pdf/05_ant_Ton_Nga_Chang.pdf
• description - Canopy ants were examined in terms of a number of species and species composition between in high and low disturbance sites of lowland tropical rainforest at Ton Nga Chang Wildlife Sanctuary, Songkhla province, Thailand, from November 2001 to November 2002. A permanent plot of 100x100 m2 was set up and divided into 100 sub-units (10x10m2) on each study site. Pyrethroid fogging was two monthly applied to collect ants on three trees at random in a permanent plot. A total of 118 morphospecies in 29 genera belonging to six subfamilies were identified. The Formicinae subfamily found the highest species numbers (64 species) followed by Myrmicinae (32 species), Pseudomyrmecinae (10 species), Ponerinae (6 species), Dolichoderinae (5 species) and Aenictinae (1 species). Myrmicinae and Ponerinae showed a significant difference of mean species number between sites (P<0.05) while Formicinae and Myrmicinae also showed a significant difference of mean species number between months (P<0.05). However, there were no interactions between sites and months in any subfamily.
279. Crop model and its application in para rubber
• date - 2007
• creator - Chiarawipa, R.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/29-3_online/0125-3395-29-3-0685-0695.pdf
• description - Crop models are derived from quantitative models that comprise empirical models and mechanistic models. Four situations of crop production were used in crop modeling. 1) potential crop production, 2)water-limited crop production, 3) nitrogen-limited crop production and 4) other plant nutrient-limited crop production. Crop modeling can be used to predict the limiting factors of rubber trees. It was found that theestimated rubber yield is highly correlated with the actual yield. Moreover, this method may be used to assistin the rubber decision-making systems and rubber simulation model. Therefore, the crop model can be applied to predict the actual yield and enhance rubber production potential.
280. Assessment of fruit density and leaf number: fruit to optimize crop load of mangosteen
• date - 2006
• creator - Sayan Sdoodee
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2006&volume=28&issue=5&spage=921
281. Use of an infrared thermometer for assessment of plant water stress in neck orange (Citrus reticulata Blanco)
• date - 2006
• creator - Sayan Sdoodee
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/28_6_pdf/02-infrared.pdf
• description - In general, water stress causes stomatal closure in citrus, and this leads to higher leaf temperature. Recently, it has been reported that infrared thermometry technique can be used for detecting stomatal closure indirectly to assess plant water stress. Therefore, it was proposed to apply to neck orange. An experiment was arranged as a completely randomized design. There were 3 treatments of watering levels: 1) wellwatering (W1), 2) 3-day interval watering (W2), and 3) 6-day interval watering (W3) with 6 replicates. Eighteen 2-year-old trees of neck orange were used, and each tree was grown in a container (0.4 m3) filled with mixed media of soil, compost and sand (1:1:1). During 18 days of the experimental period, it was found that leaf water potential and stomatal conductance of the plants in W2 and W3 treatments decreased with the progress of water stress. There was high correlation (r2 = 0.71**) between leaf water potential and stomatal conductance as a linear regression (Y = 0.0044X-1.8635). Canopy temperature (Tc) and air temperature (Ta) of each tree were measured by an infrared thermometer, and Tc-Ta was assessed. At the end of the experimental period, it was found that Tc-Ta was significantly highest in the W3 treatment (3.5ºC) followed by the of W2 treatment (2ºC), while it was lowest in the W1 treatment (1ºC). The relationship between Tc-Ta and stomatal conductance was high as polynomial (Y = 0.0002X2 0.0572X+3.9878, r2 = 0.70**). This indicated that stomatal closure or decreasing stomatal conductance caused increasing of Tc-Ta in the leaves. Hence, it suggests that infrared thermometer is a convenient device for the assessment of plant water stress in neck orange.
282. The ant nest of Crematogaster rogenhoferi (Mayr, 1879) (Hymenoptera: Formicidae) at Tarutao National Park, Satun Province, Southern Thailand
• date - 2006
• creator - Suparoek Watanasit
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2006&volume=28&issue=4&spage=723
• description - Nests of the ant Crematogaster rogenhoferi (Mayr, 1879) were investigated at Tarutao National Park, Satun Province. Fifteen ant nests were selected at random along Phante Malacca Bay between the 2-7 March 2004. They built their nests from leaf and stick debris on branches of trees, at between 248-469 cm above the ground level. The vegetation on which nests were built was composed of 5 species: Vitex pinnata L., Oleasalicifolia Wall, Syzygium gratum (Wight), Ardisia elliptica Thum and one unknown species. The physical features of each nest were recorded. The average dimensions of the nest width and length were 10.65±2.57 cm and 22.10±1.22 cm, respectively.Each nest was cut into small pieces for counting the numbers of each caste and developing stages. The results showed that the average number of queens, winged females, males and workers in each nest were 1.53±0.38, 1,753.33±506.55, 4,970.67±2,227.00, 15,577.93±2,637.84 respectively, while the developing stages of pupae, larvae, eggs were 1,589.93±480.37, 4,113.20±1,469.49 and 1,942.80±741.67 respectively. Thus the total number of ants in the population in each nest was 29,949.40±5,358.31.The relationships between the number of castes, developing stages and physical features of the nests were explored. The Spearman Rank Correlation indicated that the width of nest positively correlated with the number of queens (rs = 0.862, p = . 000), winged females (rs = 0.691, p = 0.004) and workers (rs = 0.667, p = 0.007). A comparison of the effects of vegetation types on the number of castes and development stages, showed that vegetation type did have an influence but only on the number of the worker caste (F = 7.712, P = 0.011, one-way ANOVA). Most workers were associated with nests from Vitex pinnata. No nests were found on the dominant tree species of the area probably due to its ability to produce an insect repellant oil.
283. The effects of paclobutrazol application on physiological responses, flowering and fruit qualities of longkong (Aglaia dookkoo Griff.)
• date - 2005
• creator - Sdoodee, S.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27_openweek_suppl3_pdf/08_longkong.pdf
• description - Ways of alleviating the incidence of alternate bearing in longkong by flowering induction using a chemical method (paclobutrazol ) were investigated at an experimental plot of the Department of Plant Science, Faculty of Natural Resources, Prince of Songkla University, Hat Yai campus, Songkhla Province between December, 2001 and November, 2002. Twelve 10-year-old longkong trees grown in the experimental plot were used. The experiment was arranged as a completely randomized design in 4 treatments with 3 replications. The treatments were 1) control, 2) 1 g pt-1 of paclobutrazol application 3) 2 g pt 1 of paclobutrazol application and 4) 4 g pt-1 of paclobutrazol application. It was found that all paclobutrazol applications decreased plant water use, physiological responses (leaf water potential, stomatal conductance and chlorophyll fluorescences) and leaf nitrogen content, compared with the control. Paclobutrazol application increased flowering, fruit setting and fruit qualities. Paclobutrazol application of 4 g pt-1 gave a higher number of floral buds/plant than the other treatments. Paclobutrazol application of 1 g pt-1 gave higher fruit/cluster and fruit weight/cluster than the other treatments. Paclobutrazol application significantly increased total soluble solids, but there was no effect on titratable acidity. It was also noted that the paclobutrazol application increased peel thickness.
284. Induction of embryogenic callus and plantlet regeneration from young leaves of high yielding mature oil palm
• date - 2004
• creator - Yeedum, I.
• provider - NSDL OAI Repository
• location - http://www.doaj.org/doaj?func=openurl&genre=article&issn=01253395&date=2004&volume=26&issue=5&spage=617
• description - Callus induction and plantlet regeneration from young leaves of high-yielding mature oil palm were carried out using 10-year and 20-year-old trees from Thepa Research Station, Faculty of Natural Resources,Prince of Songkla University, Hat Yai, and Trang Agricultural College, respectively. Culture media used in this experiment were Murashige and Skoog (1962) and Oil Palm supplemented with various concentrations of α-naphthaleneacetic acid (NAA) or 2,4- dichlorophenoxy acetic acid (2,4-D) or dicamba (Di) and antioxidants.Young leaves from 6th to 11st frond were excised, sterilized, cut into 5x5 mm pieces and cultured in the dark at 26±4ºC or 28±0.5ºC for 3 months. The results revealed that MS medium with 200 mg/l ascorbic acid (As) and 1 mg/l Di (MS-AsDi) gave the highest callus induction percentage (7.93) after culture for 3 months at 28±0.5ºC. Leaf segments from 6th - 8th frond yielded callus forming percentage at 10% (averaged from 1, 2.5 and 5 mg/l Di containing MS medium). Ascorbic acid as an antioxidant at concentration of 200 mg/l supplemented in MS medium in the presence of 2.5 mg/l Di produced the highest callus induction percentage (11.2) and number of nodules (7.06). A high percentage of embryogenic callus formation (66.67) was obtained when the calli were transferred to the same medium component supplemented with 0.5 mg/l Di and 1,000 mg/l casein hydrolysate (CH) (MS-AsDiCH). Haustorial-staged embryos were observed to be isolated as an individual embryo and germinated on MS medium without plant growth regulator (MS-free). Development of root could be classified into two distinct types, fibrous and tap root.
285. eNature Online field guides
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.enature.com/home/
• description - eNature Online provides a searchable database for identifying more than 4,000 plant and animal species of North America.
286. From Gene Trees to Organismal Phylogeny in Prokaryotes:The Case of the γ-Proteobacteria
• date - 2003-10
• creator - Emmanuelle Lerat
• provider - NSDL OAI Repository
• location - http://dx.doi.org/10.1371%2Fjournal.pbio.0000019
• description - The study demonstrates that single-copy orthologous genes are resistant to horizontal transfer and can be used to generate robust hypotheses for organismal phylogenies.
287. Diversity in evolving systems : scaling and dynamics of genealogical trees
288. Generating Trees of (Reducible) 1324-avoiding Permutations
• date - 2005-12-22
• creator - Marinov, Darko
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30426
• description - We consider permutations that avoid the pattern 1324. We give exact formulas for thenumber of reducible 1324-avoiding permutations and the number of {1324, 4132, 2413, 3241}-avoiding permutations. By studying the generating tree for all 1324-avoiding permutations,we obtain a recurrence formula for their number. A computer program provides data for thenumber of 1324-avoiding permutations of length up to 20.
289. On Our Experience with Modular Pluggable Analyses
• date - 2005-12-19T23:39:47Z
• creator - Lam, Patrick
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30421
• description - We present a technique that enables the focused applicationof multiple analyses to di erent modules in thesame program. In our approach, each module encapsulatesone or more data structures and uses membershipin abstract sets to characterize how objects participatein data structures. Each analysis veri es that the implementationof the module 1) preserves important internaldata structure consistency properties and 2) correctlyimplements an interface that uses formulas in a set algebrato characterize the e ects of operations on theencapsulated data structures. Collectively, the analysesuse the set algebra to 1) characterize how objects participatein multiple data structures and to 2) enable theinter-analysis communication required to verify propertiesthat depend on multiple modules analyzed by differentanalyses.We have implemented our system and deployed threepluggable analyses into it: a ag analysis for modulesin which abstract set membership is determined by aag eld in each object, a plugin for modules that encapsulatelinked data structures such as lists and trees,and an array plugin in which abstract set membershipis determined by membership in an array. Our experimentalresults indicate that our approach makes it possibleto e ectively combine multiple analyses to verifyproperties that involve objects shared by multiple modules,with each analysis analyzing only those modulesfor which it is appropriate.
290. Approximating Buy-at-Bulk k-Steiner trees
• date - 2006-01-05T20:37:59Z
• creator - Hajiaghayi, MohammadTaghi
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30601
• description - In the buy-at-bulk $k$-Steiner tree (or rent-or-buy$k$-Steiner tree) problem we are given a graph $G(V,E)$ with a setof terminals $T\subseteq V$ including a particular vertex $s$ calledthe root, and an integer $k\leq |T|$. There are two cost functionson the edges of $G$, a buy cost $b:E\longrightarrow \RR^+$ and a rentcost $r:E\longrightarrow \RR^+$. The goal is to find a subtree $H$ of$G$ rooted at $s$ with at least $k$ terminals so that the cost$\sum_{e\in H} b(e)+\sum_{t\in T-s} dist(t,s)$ is minimize, where$dist(t,s)$ is the distance from $t$ to $s$ in $H$ with respect tothe $r$ cost. Our main result is an $O(\log^5 n)$-approximation forthe buy-at-bulk $k$-Steiner tree problem.To achieve this we also design an approximation algorithm forbicriteria $k$-Steiner tree. In the bicriteria $k$-Steiner tree problem weare given a graph $G$ with edge costs $b(e)$ and distance costs$r(e)$ over the edges, and an integer $k$. Our goal is to find aminimum cost (under $b$-cost) $k$-Steiner tree such that thediameter under $r$-cost is at most some given bound $D$. An$(\alpha,\beta)$-approximation finds a subgraph of diameter at most$\alpha\cdot {D}$ (with respect to $r$) and cost with respect to$b$ of at most $\beta\cdot opt$ where $opt$ is the minimum cost ofany solution with diameter at most $D$. Marathe et al \cite{ravi}gave an $(O(\log n),O(\log n))$-approximation algorithm for thebicriteria Steiner tree problem. Their algorithm does not extend tothe bicriteria $k$-Steiner tree problem.Our algorithm for the buy-at-bulk $k$-Steiner tree problem relies on an$(O(\log^2 n),O(\log^4 n))$-approximation algorithm we develop for the(shallow-light) bicriteria $k$-Steiner tree problem, which is ofindependent interest. Indeed, this is also one of the main tools we use to obtainthe first polylogarithmic approximation algorithm for non-uniformmulticommodity buy-at-bulk~\cite{HKS}.
291. Methods and Experiments With Bounded Tree-width Markov Networks
• date - 2005-12-22T02:19:52Z
• creator - Liang, Percy
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30511
• description - Markov trees generalize naturally to bounded tree-width Markov networks, onwhich exact computations can still be done efficiently. However, learning themaximum likelihood Markov network with tree-width greater than 1 is NP-hard, sowe discuss a few algorithms for approximating the optimal Markov network. Wepresent a set of methods for training a density estimator. Each method isspecified by three arguments: tree-width, model scoring metric (maximumlikelihood or minimum description length), and model representation (using onejoint distribution or several class-conditional distributions). On thesemethods, we give empirical results on density estimation and classificationtasks and explore the implications of these arguments.
292. On Decision Procedures for Set-Value Fields
• date - 2005-12-22T02:19:36Z
• creator - Kuncak, Viktor
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30509
• description - An important feature of object-oriented programming languages is the ability todynamically instantiate user-defined container data structures such as lists, trees,and hash tables. Programs implement such data structures using references todynamically allocated objects, which allows data structures to store unboundednumbers of objects, but makes reasoning about programs more difficult. Reasoningabout object-oriented programs with complex data structures is simplified if datastructure operations are specified in terms of abstract sets of objects associatedwith each data structure. For example, an insertion into a data structure in thisapproach becomes simply an insertion into a dynamically changing set-valued fieldof an object, as opposed to a manipulation of a dynamically linked structure linkedto the object.In this paper we explore reasoning techniques for programs that manipulate datastructures specified using set-valued abstract fields associated with container objects.We compare the expressive power and the complexity of specification languagesbased on 1) decidable prefix vocabulary classes of first-order logic, 2) twovariablelogic with counting, and 3) Nelson-Oppen combinations of multisortedtheories. Such specification logics can be used for verification of object-orientedprograms with supplied invariants. Moreover, by selecting an appropriate subsetof properties expressible in such logic, the decision procedures for these logics yieldautomated computation of lattice operations in abstract interpretation domain, aswell as automated computation of abstract program semantics.
293. On Spatial Conjunction as Second-Order Logic
• date - 2005-12-22T02:14:54Z
• creator - Kuncak, Viktor
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/30498
• description - Spatial conjunction is a powerful construct for reasoning about dynamically allocateddata structures, as well as concurrent, distributed and mobile computation. Whileresearchers have identified many uses of spatial conjunction, its precise expressive powercompared to traditional logical constructs was not previously known.In this paper we establish the expressive power of spatial conjunction. We construct anembedding from first-order logic with spatial conjunction into second-order logic, and moresurprisingly, an embedding from full second order logic into first-order logic with spatialconjunction. These embeddings show that the satisfiability of formulas in first-order logicwith spatial conjunction is equivalent to the satisfiability of formulas in second-order logic.These results explain the great expressive power of spatial conjunction and can be usedto show that adding unrestricted spatial conjunction to a decidable logic leads to an undecidablelogic. As one example, we show that adding unrestricted spatial conjunction totwo-variable logic leads to undecidability.On the side of decidability, the embedding into second-order logic immediately implies thedecidability of first-order logic with a form of spatial conjunction over trees. The embeddinginto spatial conjunction also has useful consequences: because a restricted form of spatialconjunction in two-variable logic preserves decidability, we obtain that a correspondinglyrestricted form of second-order quantification in two-variable logic is decidable. The resultinglanguage generalizes the first-order theory of boolean algebra over sets and is useful inreasoning about the contents of data structures in object-oriented languages.
294. Photovoltaic decision analysis
• date - 2006-03-06T16:54:56Z
• creator - Goldman, Neil L.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/31263
• description - This paper is concerned with the development and implementation of a methodology that analyzes information relating to the choice between flat plate and concentrator technologies for photovoltaic development. A Decision Analysis approach is used to compare and systematically evaluate the two photovoltaic energy conversion systems. This methodology provides a convenient framework for structuring the decision process in an orderly sequential fashion via decision trees, incorporating information on subjective probabilities of future outcomes, and focusing attention on critical options and uncertainties. A significant tenet of the analysis is that any set of energy technologies must be compared on the basis of the cost of generated energy rather than simply on the basis of the cost of hardware production. As a result, the cost analyses presented focus on a comparison of energy generated by the photovoltaic systems in units of $/kWh, rather than on a comparison based on units of$/peak kW. The criterion for choice between the alternative technologies is chosen to be minimization of expected cost per unit of energy generated. After presenting the decision tree framework used to structure the problem, including a classification of the components of the competing technologies, a detailed procedure for calculating the system cost per kilowatt-hour for each path through the decision tree is described for each technology and methods for assessing subjective probability distributions are discussed.
295. Appropriate water treatment for the Nyanza Province of Kenya
• date - 2006-02-02T18:50:32Z
• creator - Alekal, Pragnya Y. (Pragnya Yogesh), 1977-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/31124
• description - M.Eng.
296. Multiscale statistical signal processing : stochastic processes indexed by trees
297. Extremal problems in combinatorial geometry and Ramsey theory
298. Nonlinear trajectory optimization with path constraints applied to spacecraft reconfiguration maneuvers
• date - 2006-03-29T18:45:24Z
• creator - GarcÃ­a, Ian Miguel
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/32448
• description - Includes bibliographical references (p. 115-120).
299. Design of a press for oil extraction from moringa seeds for Haiti
• date - 2006-05-15T20:29:48Z
• creator - Sabelli, Alessandra Maria, 1976-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/32783
• description - The project here presented focuses on the development of a harvesting tool for Haiti, a developing country, for the extraction of oil from the seeds of the moringa trees. Moringas have an extraordinarily nutritional potential that can help, at least short-term, to solve problems associated with poor nutrition in the area. Furthermore, moringas naturally prosper in Haiti, making it an accessible and inexpensive resource. A first design is presented in this thesis along with the relevant experimentation and results, and progressive development of possible designs. One of the major concerns regarding the extraction process has been the reabsorption of the oil due to the elastic property of the seeds. This factor is important because a significant percentage of the oil extracted can potentially be reabsorbed, consequently limiting the efficiency of the extraction process. I consequently selected a continuous system that could better ensure a constant pressure, which seems desirable. Moreover, inevitably the design is a compromise between efficiency and cost. Therefore, it was necessary to select a design that could be cheaply produced, limiting also the necessity to produce the whole design from scratch. The final design consists of a meat grinder that ends with a cage shaped as section of a cone, the whole being powered by human pedaling. Fresh seeds are inserted in a cone-shaped feeder, while the cake flows out the smaller end of the cage and oil is collected in a container. This project represents a first step into the development of an extraction tool that maximizes the extraction of oil from moringa seeds, and consequently the consumption of the seeds themselves, not exploited so far.
300. Fractal estimation using models on multiscale trees
301. On Using First-Order Theorem Provers in the Jahob Data Structure Verification System
• date - 2006-11-09T15:26:55Z
• creator - Bouillaguet, Charles
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/34874
• description - This paper presents our integration of efficient resolution-based theorem provers into the Jahob data structure verification system. Our experimental results show that this approach enables Jahob to automatically verify the correctness of a range of complex dynamically instantiable data structures, including data structures such as hash tables and search trees, without the need for interactive theorem proving or techniques tailored to individual data structures. Our primary technical results include: (1) a translation from higher-order logic to first-order logic that enables the application of resolution-based theorem provers and (2) a proof that eliminating type (sort) information in formulas is both sound and complete, even in the presence of a generic equality operator. Our experimental results show that the elimination of type information dramatically decreases the time required to prove the resulting formulas. These techniques enabled us to verify complex correctness properties of Java programs such as a mutable set implemented as an imperative linked list, a finite map implemented as a functional ordered tree, a hash table with a mutable array, and a simple library system example that uses these container data structures. Our system verifies (in a matter of minutes) that data structure operations correctly update the finite map, that they preserve data structure invariants (such as ordering of elements, membership in appropriate hash table buckets, or relationships between sets and relations), and that there are no run-time errors such as null dereferences or array out of bounds accesses.
302. Ozone effects on net primary production and carbon sequestration in the conterminous United States using a biogeochemistry model
• date - 2003-10-24T14:55:37Z
• creator -
• provider - NSDL OAI Repository
• location - http://mit.edu/globalchange/www/abstracts.html#a90
• description - Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/)
303. Automatic record extraction for the World Wide Web
• date - 2007-01-10T16:47:43Z
• creator - Shen, Yuan Kui
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/35609
• description - Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2006.
304. Radar range profile simulation of isolated trees with radiative transfer theory
• date - 2007-03-12T17:32:46Z
• creator - Gung, Tza-Jing
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36572
• description - Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
305. 3.A24 Freshman Seminar: The Engineering of Birds, Fall 2004
• date - 2007-03-19T13:05:18Z
• creator - Gibson, Lorna J.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36851
• description - Why are things in nature shaped the way they are? How do birds fly? Why do bird nests look the way they do? How do woodpeckers peck? These are the types of questions Dr. Lorna Gibson's freshman seminar at MIT has been investigating. We invite you to explore with us. Questions such as these are the subject of biomimetic research. When engineers copy the shapes found in nature we call it Biomimetics. The word biomimic comes from bio, as in biology and mimetic, which means to copy. Join us as we explore and look for answers to why similar shapes occur in so many natural things and how physics change the shape of nature.
306. Replication control in distributed B-trees
• date - 2007-04-03T16:55:43Z
• creator - Cosway, Paul Richard
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/36957
• description - Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
307. Observation of Joule Heating-Assisted Electromigration Failure Mechanisms for Dual Damascene Cu/SiOâ Interconnects
• date - 2003-11-24T21:03:56Z
• creator - Chang, Choon Wai
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/3727
• description - Singapore-MIT Alliance (SMA)
308. Product and program management : battling the strangler trees of system and social complexity in the software market jungle
• date - 2007-07-18T13:20:33Z
• creator - Hempe, John A. (John Alan)
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/37984
• description - Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2006.
309. New techniques for geographic routing
• date - 2007-07-18T13:08:00Z
• creator - Leong, Ben Wing Lup
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/37907
• description - Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.
310. Algorithmic embeddings
• date - 2007-07-18T13:06:12Z
• creator - Bădoiu, Mihai, 1978-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/37898
• description - (cont.) We present results for different types of distortion: multiplicative versus additive, worst-case versus average-case and several types of target metrics, such as the line, the plane, d-dimensional Euclidean space, ultrametrics, and trees. We also present algorithms for ordinal embeddings and embedding with extra information.
311. Capacitated Trees, Capacitated Routing, and Associated Polyhedra
• date - 2004-05-28T19:27:25Z
• creator - Araque, JÃ©sus Rafael
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5194
• description - We study the polyhedral structure of two related core combinatorial problems: the subtree cardinalityconstrained minimal spanning tree problem and the identical customer vehicle routing problem. For each of these problems, and for a forest relaxation of the minimal spanning tree problem, we introduce a number of new valid inequalities and specify conditions for ensuring when these inequalities are facets for the associated integer polyhedra. The inequalities are defined by one of several underlying support graphs: (i) a multistar, a "star" with a clique replacing the central vertex; (ii) a clique cluster, a collection of cliques intersecting at a single vertex, or more generally at a central" clique; and (iii) a ladybug, consisting of a multistar as a head and a clique as a body. We also consider packing (generalized subtour elimination) constraints, as well as several variants of our basic inequalities, such as partial multistars, whose satellite vertices need not be connected to all of the central vertices. Our development highlights the relationship between the capacitated tree and capacitated forest polytopes and a so-called path-partitioning polytope,and shows how to use monotone polytopes and a set of simple exchange arguments to prove that valid inequalities are facets.
312. Optimal Trees
313. Optimizing Constrained Subtrees of Trees
• date - 2004-06-01T16:43:08Z
• creator - Aghezzaf, El Houssaine
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5407
• description - Given a tree G = (V, E) and a weight function defined on subsets of its nodes, we consider two associated problems. The first, called the "rooted subtree problem", is to find a maximum weight subtree, with a specified root, from a given set of subtrees. The second problem, called "the subtree packing problem", is to find a maximum weight packing of node disjoint subtrees chosen from a given set of subtrees, where the value of each subtree may depend on its root. We show that the complexity status of both problems is related, and that the subtree packing problem is polynomial if and only if each rooted subtree problem is polynomial. In addition we show that the convex hulls of the feasible solutions to both problems are related: the convex hull of solutions to the packing problem is given by "pasting together" the convex hulls of the rooted subtree problems. We examine in detail the case where the set of feasible subtrees rooted at node i consists of all subtrees with at most k nodes. For this case we derive valid inequalities, and specify the convex hull when k < 4.
314. Prism Trees: An Efficient Representation for Manipulating and Displaying Polyhedra with Many Faces
• date - 2004-10-01T20:10:44Z
• creator - Ponce, Jean
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5609
• description - Computing surface and/or object intersections is a cornerstone of many algorithms in Geometric Modeling and Computer Graphics, for example Set Operations between solids, or surface Ray Casting display. We present an object centered, information preserving, hierarchical representation for polyhedra called Prism Tree. We use the representation to decompose the intersection algorithms into two steps: the localization of intersections, and their processing. When dealing with polyhedra with many faces (typically more than one thousand), the first step is by far the most expensive. The Prism Tree structure is used to compute efficiently this localization step. A preliminary implementation of the Set Operations and Ray casting algorithms has been constructed.
315. A Method for Eliminating Skew Introduced by Non-Uniform Buffer Delay and Wire Lengths in Clock Distribution Trees
• date - 2004-10-04T14:15:55Z
• creator - Wu, Henry M.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/5949
• description - The computation of a piecewise smooth function that approximates a finite set of data points is decomposed into two decoupled tasks: first, the computation of the locally smooth models, and hence, the segmentation of the data into classes that consist on the sets of points best approximated by each model, and second, the computation of the normalized discriminant functions for each induced class. The approximating function is then computed as the optimal estimator with respect to this measure field. Applications to image processing and time series prediction are presented as well.
316. A Heuristic Program that Constructs Decision Trees
• date - 2004-10-04T14:44:14Z
• creator - Winston, Patrick
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6175
• description - Suppose there is a set of objects, {A, B,...E} and a set of tests, {T1, T2,...TN). When a test is applied to an object, the result is wither T or F. Assume the test may vary in cost and the object may vary in probability or occurrence. One then hopes that an unknown object may be identified by applying a sequence if tests. The appropriate test at any point in the sequence in general should depend on the results of previous tests. The problem is to construct a good test scheme using the test cost, the probabilities of occurrence, and a table of test outcomes.
317. Learning Classes Correlated to a Hierarchy
• date - 2004-10-08T20:38:58Z
• creator - Shih, Lawrence
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6719
• description - Trees are a common way of organizing large amounts of information by placing items with similar characteristics near one another in the tree. We introduce a classification problem where a given tree structure gives us information on the best way to label nearby elements. We suggest there are many practical problems that fall under this domain. We propose a way to map the classification problem onto a standard Bayesian inference problem. We also give a fast, specialized inference algorithm that incrementally updates relevant probabilities. We apply this algorithm to web-classification problems and show that our algorithm empirically works well.
318. On Directional Selectivity in Vertebrate Retina: An Experimental and Computational Study
• date - 2004-10-20T19:57:21Z
• creator - Borg-Graham, Lyle J.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6804
• description - This thesis describes an investigation of retinal directional selectivity. We show intracellular (whole-cell patch) recordings in turtle retina which indicate that this computation occurs prior to the ganglion cell, and we describe a pre-ganglionic circuit model to account for this and other findings which places the non-linear spatio-temporal filter at individual, oriented amacrine cell dendrites. The key non-linearity is provided by interactions between excitatory and inhibitory synaptic inputs onto the dendrites, and their distal tips provide directionally selective excitatory outputs onto ganglion cells. Detailed simulations of putative cells support this model, given reasonable parameter constraints. The performance of the model also suggests that this computational substructure may be relevant within the dendritic trees of CNS neurons in general.
319. AMAR: A Computational Model of Autosegmental Phonology
• date - 2004-10-20T19:55:03Z
• creator - Albro, Daniel M.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6788
• description - This report describes a computational system with which phonologists may describe a natural language in terms of autosegmental phonology, currently the most advanced theory pertaining to the sound systems of human languages. This system allows linguists to easily test autosegmental hypotheses against a large corpus of data. The system was designed primarily with tonal systems in mind, but also provides support for tree or feature matrix representation of phonemes (as in The Sound Pattern of English), as well as syllable structures and other aspects of phonological theory. Underspecification is allowed, and trees may be specified before, during, and after rule application. The association convention is automatically applied, and other principles such as the conjunctivity condition are supported. The method of representation was designed such that rules are designated in as close a fashion as possible to the existing conventions of autosegmental theory while adhering to a textual constraint for maximum portability.
320. CARPS: A Program which Solves Calculus Word Problems
• date - 2004-10-20T20:05:47Z
• creator - Charniak, Eugene
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/6901
• description - A program was written to solve calculus word problems. The program, CARPS (CALculus Rate Problem Solver), is restricted to rate problems. The overall plan of the program is similar to Bobrow's STUDENT, the primary difference being the introduction of "structures" as the internal model in CARPS. Structures are stored internally as trees. Each structure is designed to hold the information gathered about one object. A description of CARPS is given by working through two problems, one in great detail. Also included is a critical analysis of STUDENT.
321. Hierarchical Mixtures of Experts and the EM Algorithm
• date - 2004-10-20T20:49:48Z
• creator - Jordan, Michael I.
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/7206
• description - We present a tree-structured architecture for supervised learning. The statistical model underlying the architecture is a hierarchical mixture model in which both the mixture coefficients and the mixture components are generalized linear models (GLIM's). Learning is treated as a maximum likelihood problem; in particular, we present an Expectation-Maximization (EM) algorithm for adjusting the parameters of the architecture. We also develop an on-line learning algorithm in which the parameters are updated incrementally. Comparative simulation results are presented in the robot dynamics domain.
322. Using Structural Analysis to Mediate XML Semantic Interoperability
• date - 2002-06-07T20:45:31Z
• creator - Mishra, Ashish
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/713
• description - At the forefront of interoperability using XML in an Internet environment is the issue of semantic trans-lation; that is, the ability to properly interpret the elements, attributes, and values contained in an XML file. In many cases, specific domains have standardized the way data are represented in XML. When this does not occur, some type of mediation is required to interpret XML formatted data that does not adhere to pre-defined semantics. The prototype X-Map was developed to investigate what is required to mediate semantic interoperability between heterogeneous domains. An essential component of this system is structural analysis of data representations in the respective domains. When mediating XML data between similar but non-identical domains, we cannot rely solely on semantic similarities of tags and/or the data content of elements to establish associations between related elements, especially over the Internet. To complement these discovered associations one can attempt to build on relationships based on the respective domain structures and the position and relationships of evaluated elements within those structures. For this purpose, the domains are represented as hierarchical trees in XML syntax; a more general solution handles arbitrary graphs. A structural analysis algorithm builds on associations discovered by other analysis, using these associations to aid in discovering further links that could not have been discovered by purely static examination of the elements and their aggregate content. A number of methodologies are presented by which the algorithm maximizes the number of relevant mappings or associations derived from the XML structures. The paper concludes with comparative results obtained using these three methodologies.
323. Systematic conformational search with constraint satisfaction
324. Consistent hashing and random trees : algorithms for caching in distributed networks
• date - 2005-08-19T14:27:13Z
• creator - Lewin, Daniel M. (Daniel Mark), 1970-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/9947
• description - Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.
325. Impacto de la Bioinformática en las ciencias biomédicas
• date - 2003-01-01
• creator - Arencibia Jorge, Ricardo
• provider - NSDL OAI Repository
• location - http://eprints.rclis.org/archive/00001767/
• description - [Spanish abstract] Durante la última década del siglo XX, los avances de la ingeniería genética y las nuevas tecnologías de la información, condicionaron el surgimiento de una disciplina que creó vínculos indisolubles entre la Informática y las ciencias biológicas: la Bioinformática. Se realizó un análisis bibliométrico en la base de datos Medline con vistas a medir su impacto en las ciencias médicas. Sus principales aplicaciones, según los resultados obtenidos, fueron la gestión de datos en los laboratorios, la automatización de experimentos, el ensamblaje de secuencias contiguas, la predicción de dominios funcionales en secuencias génicas, la alineación de secuencias, las búsquedas en bases de datos de estructuras, la determinación y predicción de la estructura de las macromoléculas, la evolución molecular y los árboles filogenéticos. Las especialidades médicas que recibieron una mayor influencia de la Bioinformática fueron la Genética Médica, la Bioquímica Clínica, la Farmacología, las Neurociencias, la Estadística Médica, la Inmunología, la Fisiología y la Oncología. [English abstract] The advances reached by the genetic engineering and the development of new information technologies during the last decade, conditioned the emergence of a discipline that has created indissoluble bonds between the Computer Sciences and the Biological Sciences: the Bioinformatics. The present work demonstrates the impact of the Bioinformatics in the Medical Sciences, through the bibliometric analysis of MEDLINE, the most important database of the biomedical environment at the present time. The main applications of this discipline in the registrations obtained in MEDLINE were directed to the data management in the laboratory, the automation of experiments, the assembling of contiguous sequences, the prediction of functional domains in gene sequences, the alignment of sequences, the searches in databases of structures, the structure determination and prediction of macro-molecules, the molecular evolution and the phylogenetic trees. The medical specialties mostly influenced by the Bioinformatics were the Medical Genetics, Clinical Biochemistry, Pharmacology, Neurosciences, Medical Statistic, Immunology, Physiology and Oncology.
326. Las palmeras argentinas a través de una bibliografía
• date - 1983-01-01
• creator - Dimitri, Pedro Jorge
• provider - NSDL OAI Repository
• location - http://eprints.rclis.org/archive/00007855/
• description - [Spanish abstract]El presente trabajo consta de 131 asientos bibliográficos relativos a palmeras vivientes y fósiles, cada uno de ellos tenidos en nuestras manos y extractados de publicaciones periódicas y libros de biología y botánica, de origen nacional y extranjero. Está clasificado de acuerdo a los epígrafes de Rovira y Aguayo, semejante a subject heandings of Library of Congress. Por último y en base a la cantidad de híbridos entre Butia y Arecastrum y Syagrus, por un lado y el concepto moderno de especie que da como uno de los caracteres distintivos la herencia común, por el otro, hacemos un comentario acerca de la posibilidad de la fusión de Butia, Arecastrum y Syagrus. English abstract: This paper includes 131 articles concerning existing or fossil palm trees, each one of them had in our hands and extracted form periodicals and books on biology and botany, national or foreing. Finally, and based on the ammount of hybrids between Butia & Arecastrum & Syagrus, on one hand, an the modern concept of species which gives as one of the distinctive characters the common heritage, on the other, we comment the possibility of the hybridization between Butia & Arecastrum & Syagrus
327. New Zealand Tree Crops Association information
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.treecrops.org.nz/
• description - Description of the New Zealand association interested in tree crops (fruit, nuts, animal fodder), including lists of activities, branches and publications.
328. SimForest
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://ddc.hampshire.edu/simforest/software/software.html
• description - SimForest is a cross platform application which can be used by individual students, small groups, or an entire class. Students can plant trees from a pool of over 30 New England species, set environmental parameters such as rain fall, temperature, and soil conditions, and watch the forest plot grow and evolve over many years. Graphing and analysis tools are provided within the programs for collection of hard copy data.
329. Managing Your Property for Wildlife
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.dnr.state.oh.us/wildlife/Resources/mgtplans/mgtplans.htm
• description - This is an extensive site provided by the Ohio Department of Natural Resources Division of Wildlife. Twelve different wildlife habitat management plans are available to download as PDF files. Management topics include: prairie grassland, pasture/hayland, artificial nesting structures, cool season grassland, cropfield management, food plots, old fields, planting trees & shrubs, riparian habitat, urban landscape, wetland habitat, and woodland habitat. These files provide excellent information to landowners, students, and wildlife managers.
330. University of New Hampshire ForestWatch
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://www.forestwatch.sr.unh.edu/
• description - Students and Scientists Working Together Determining the Health of New England's Forests. Spreadsheets can be downloaded (free!) for teachers to use in gathering their own data.
331. Endangered Species Act (ESA)
• date - 1973
• creator -
• provider - NSDL OAI Repository
• location - http://www.epa.gov/region5/defs/html/esa.htm
• description - Summary of the ESA with links to Full-text of Environmental Species Act and 7 USC 136, Environmental Pesticide Control through Cornell University.
332. weight-balanced binary trees are ultrametric
• date - 2005-04-14
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/WeightBalancedBinaryTreesAreUltrametric.html
• description - Let <i>X</i> be the set of leaf nodes in a weight-balanced binary tree. Let the distance between leaf nodes be identified with the weighted path length between them. We will show that this distance metric on <i>X</i> is ultrametric. Before we begin, let the join of any two nodes ... , denoted ... , be defined as the node <i>z</i> which is the most immediate common ancestor of <i>x</i> and <i>y</i> (that is, the common ancestor which is farthest from the root). Also, we are using weight-balanced in the sense that ... the weighted path length from the root to each leaf node is equal, and ... each subtree is weight-balanced, too. ... Because the tree is weight-balanced, the distances between any node and each of the leaf node descendents of that node are equal. So, for any leaf nodes ... , ... Hence, ... We will now show that the ultrametric three point condition holds for any three leaf nodes in a weight-balanced binary tree. Consider any three points ... in a weight-balanced binary tree. If there exists a renaming of ... such that ... , then the three point condition holds. Now assume this is not the case. Without loss of generality, assume that ... . Applying Eqn. ... , ... Note that both ... and ... are ancestors of <i>a</i>. Hence, ... is a more distant ancestor of <i>a</i> and so ... must be an ancestor of ... . Now, consider the path between <i>b</i> and <i>c</i>. to get from <i>b</i> to <i>c</i> is to go from <i>b</i> up to ... , then up to ... , and then down to <i>c</i>. Since this is a tree, this is the only path. The highest node in this path (the ancestor of both b and c) was ... , so the distance ... . But by Eqn. ... and Eqn. ... (noting that <i>b</i> is a descendent of ... ), we have ... To summarize, we have ... , which is the desired ultrametric three point condition. So we are done. Note that this means that, if ... are leaf nodes, and you are at a node outside the subtree under ... , then ... . In other words, (from the point of view of distance between you and them,) the of any subtree that is not your own doesn't matter to you. This is expressed in the three point condition as ... . (above, we have only proved this if you are at a leaf node, but it works for any node which is outside the subtree under ... , because the paths to <i>a</i> and <i>b</i> must both pass through ... ).
333. Wedderburn-Etherington number
• date - 2007-03-16
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/WedderburnEtheringtonNumber.html
• description - The <i>n</i>th ... Wedderburn-Etherington number counts how many weakly binary trees can be constructed such that each graph vertex (not counting the root vertex) is adjacent to no more than three other such vertices, for a given number <i>n</i> of nodes. The first few Wedderburn-Etherington numbers are 1, 1, 1, 2, 3, 6, 11, 23, 46, 98, 207, 451, 983, etc. listed in A001190 of Sloane's OEIS. Michael Somos gives the following recurrence relations: ... and ... with ... in both relations.
334. ultrametric
• date - 2007-06-02
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/Ultrametric.html
• description - Any metric ... on a set <i>X</i> must satisfy the triangle inequality: ... An ... ultrametric must additionally satisfy a stronger version of the triangle inequality: ... Here is an example of an ultrametric on a space with 5 points, labelled ... : ... In the table above, an entry <i>n</i> in the for element <i>x</i> and the for element <i>y</i> indicates that ... , where <i>d</i> is the ultrametric. By symmetry of the ultrametric ( ... ), the above table yields all values of ... for all ... . The ultrametric condition is equivalent to the ultrametric three point condition: ... Ultrametrics can be used to model bifurcating hierarchical systems.\, The distance between nodes in a weight-balanced binary tree is an ultrametric. Similarly, an ultrametric can be modelled by a weight-balanced binary tree, although the choice of tree is not necessarily unique.\, Tree models of ultrametrics are sometimes called ... ultrametric trees . The metrics induced by non-Archimedean valuations are ultrametrics.
335. tree traversals
• date - 2006-07-24
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/TreeTraversals.html
• description - A ... tree traversal is an algorithm for visiting all the Graph in a rooted tree exactly once. The constraint is on rooted trees, because the root is taken to be the starting point of the traversal. A traversal is also defined on a forest in the sense that each tree in the forest can be iteratively traversed (provided one knows the roots of every tree beforehand). This entry presents a few common and simple tree traversals. In the description of a forest , the notion of rooted-subtrees was presented. Full understanding of this notion is necessary to understand the traversals presented here, as each of these traversals depends heavily upon this notion. In a traversal, there is the notion of ... visiting a node. Visiting a node often consists of doing some computation with that node. The traversals are defined here without any notion of what is being done to visit a node, and simply indicate where the visit occurs (and most importantly, in what order). Examples of each traversal will be illustrated on the following binary tree. ... Vertices will be numbered in the order they are visited, and edges will be drawn with arrows indicating the path of the traversal. ... Given a rooted tree, a ... preorder traversal consists of first visiting the root, and then executing a preorder traversal on each of the root's children (if any). For example ... The term ... preorder refers to the fact that a node is visited ... before any of its descendents. A preorder traversal is defined for any rooted tree. As pseudocode, the preorder traversal is ... (x, ... ) ... { ... Input : A node <i>x</i> of a binary tree, with children ... and ... , and some computation ... defined for <i>x</i>} ... { ... Output : Visits nodes of subtree rooted at <i>x</i> in a preorder traversal} ... { ... Procedure :} ... (x) ... ( ... (x), ... ) ... ( ... (x), ... ) ... Given a rooted tree, a ... postorder traversal consists of first executing a postorder traversal on each of the root's children (if any), and then visiting the root. For example ... As with the preorder traversal, the term ... postorder here refers to the fact that a node is visited ... after all of its descendents. A postorder traversal is defined for any rooted tree. As pseudocode, the postorder traversal is ... (x, ... ) ... { ... Input : A node <i>x</i> of a binary tree, with children ... and ... , and some computation ... defined for <i>x</i>} ... { ... Output : Visits nodes of subtree rooted at <i>x</i> in a postorder traversal
336. root (of a tree)
• date - 2006-01-31
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/RootOfATree.html
• description - The ... root of a tree is a place-holder node. It is typically drawn at the top of the page, with the other nodes below (with all nodes having the same path distance from the root at the same height.) ... Figure: A tree with root highlighted in red. ... Any tree can be redrawn this way, selecting any node as the root. This is important to note: taken as a graph in general, the notion of ... is meaningless. We introduce a root explicitly when we begin speaking of a graph as a tree-- there is nothing in general that selects a root for us. However, there are some special cases of trees where the root can be distinguished from the other nodes implicitly due to the properties of the tree. For instance, a root is uniquely identifiable in a complete binary tree, where it is the only node with degree two. Further, in a ... directed tree , there can be only one root. This is because all nodes must be reachable from that node by following the arrows between them in the proper direction.
337. proof of Nielsen-Schreier theorem and Schreier index formula
• date - 2004-09-07
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/ProofOfNielsenSchreierTheoremAndSchreierIndexFormula.html
• description - While there are purely algebraic proofs of the Nielsen-Schreier theorem, a much easier proof is available through geometric group theory. Let <i>G</i> be a group which is free on a set <i>X</i>. Any group acts freely on its Cayley graph, and the Cayley graph of <i>G</i> is a ... -regular tree, which we will call ... . If <i>H</i> is any subgroup of <i>G</i>, then <i>H</i> also acts freely on ... by restriction. Since groups that act freely on trees are free, <i>H</i> is free. Moreover, we can obtain the rank of <i>H</i> (the size of the set on which it is free). If ... is a finite graph, then ... is free of rank ... , where ... denotes the Euler characteristic of ... . Since ... , the rank of <i>H</i> is ... . If <i>H</i> is of finite index <i>n</i> in <i>G</i>, then ... is finite, and ... . Of course ... is the rank of <i>G</i>. Substituting, we obtain the Schreier index formula: ...
338. locally finite graph
• date - 2006-09-11
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/LocallyFiniteGraph.html
• description - A ... locally finite graph is a graph in which every vertex has Finite degree. Note that any finite graph is locally finite; however, infinite graphs can also be locally finite. For example, consider the graph given by ... , where the points are the vertices and the line segments of unit length that connect vertices are edges: ... Note that every vertex has degree <i>4</i> but that this is an infinite graph. The <i>k</i>- RegularGraph trees form another class of examples of locally finite graphs. A picture of a <i>2</i>-regular tree is given below ... The solid unit length dashed are edges while the dots are vertices and the dashed lines are meant to denote continuation. For a similar reason this is a locally finite graph.
339. Ihara's theorem
• date - 2003-09-05
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/IharasTheorem.html
• description - Let Gamma be a discrete, torsion-free subgroup of ... (where Q_p is the field of PAdicIntegers ). Then Gamma is free. ... [Proof, or a sketch thereof] There exists a ... regular tree <i>X</i> on which ... acts, with stabilizer ... (here, Z_p denotes the ring of PAdicIntegers ). Since Z_p is compact in its profinite topology, so is ... . Thus, ... must be compact, discrete and torsion-free. Since compact and discrete implies finite, the only such group is trivial. Thus, Gamma acts freely on <i>X</i>. Since groups acting freely on trees are free, Gamma is free. ...
340. Farey sequence
• date - 2002-06-24
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/FareySequence.html
• description - The <i>n</i>'th ... Farey sequence is the ascending sequence of all rationals ... . The first 5 Farey sequences are ... [htp] |cl| ... 1 & ... 2 & ... 3 & ... 4 & ... 5 & ... Farey sequences are a singularly useful tool in understanding the convergents that appear in continued fractions. The convergents for any irrational alpha can be found: they are precisely the closest number to alpha on the sequences ... . It is also of value to look at the sequences ... as <i>n</i> grows. If ... and ... are reduced representations of adjacent terms in some Farey sequence ... (where ... ), then they are adjacent fractions; their difference is the least possible: ... Furthermore, the ... first fraction to appear between the two in a Farey sequence is ... , in sequence ... , and (as written here) this fraction is already reduced. An alternate view of the ... of how Farey sequences develop is given by Stern-Brocot trees.
341. external path length
• date - 2002-03-07
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/ExternalPathLength.html
• description - Given a binary tree <i>T</i>, construct its extended binary tree ... . The ... external path length of <i>T</i> is then defined to be the sum of the lengths of the paths to each of the external nodes. For example, let <i>T</i> be the following tree. ... The extended binary tree of <i>T</i> is ... The external path length of <i>T</i> (denoted <i>E</i>) is ... The ... internal path length of <i>T</i> is defined to be the sum of the lengths of the paths to each of the internal nodes. The internal path length of our example tree (denoted <i>I</i>) is ... Note that in this case ... , where <i>n</i> is the number of internal nodes. This happens to hold for all binary trees.
342. Dynkin diagram
• date - 2006-01-03
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/DynkinDiagram.html
• description - Dynkin diagrams are a combinatorial way of representing the information in a root system. Their primary advantage is that they are easier to write down, remember, and analyze than explicit representations of a root system. They are an important tool in the classification of simple Lie algebras. Given a reduced root system ... , with <i>E</i> an inner-product space, choose a base or simple roots Pi (or equivalently, a set of positive roots ... ). The Dynkin diagram associated to <i>R</i> is a graph whose vertices are Pi. If pi_i and pi_j are distinct elements of the root system, we add ... lines between them. This number is obivously positive, and an integer since it is the product of 2 quantities that the axioms of a root system require to be integers. By the Cauchy-Schwartz inequality, and the fact that simple roots are never anti-parallel (they are all strictly contained in some half space), ... . Thus Dynkin diagrams are finite graphs, with single, double or triple edges. Fact, the criteria are much stronger than this: if the multiple edges are counted as single edges, all Dynkin diagrams are trees, and have at most one multiple edge. In fact, all Dynkin diagrams fall into 4 infinite families, and 5 exceptional cases, in exact parallel to the classification of simple Lie algebras. ( ... Does anyone have good Dynkin diagram pictures? I'd love to put some up, but am decidedly lacking. )
343. directed graph
• date - 2006-12-27
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/DirectedGraph.html
• description - A ... directed graph or ... digraph is a pair ... where <i>V</i> is a set of ... vertices and <i>E</i> is a subset of ... called ... edges or ... arcs . If <i>E</i> is symmetric (i.e., ... if and only if ... ), then the digraph is isomorphic to an ordinary (that is, undirected) graph. Digraphs are generally drawn in a similar manner to graphs with arrows on the edges to indicate a sense of direction. For example, the digraph ... may be drawn as ... Since the graph is directed, one has the concept of the number of edges originating or terminating at a given vertex <i>v</i>. The out-degree, ... of a vertex <i>v</i> is the number of edges having <i>v</i> as their originating vertex; similarly, the in-degree, ... is the number of edges having <i>v</i> as their terminating vertex. If the graph has a finite number of vertices, say ... , then obviously ... A ... directed path in a digraph <i>G</i> is a sequence of edges ... such that the end vertex of ... is the start vertex of ... for ... . Such a path is called a ... directed circuit if, in addition, the end vertex of ... is the start vertex of ... . A digraph is ... connected (or, sometimes, ... strongly connected ) if for every pair of vertices <i>u</i> and <i>v</i> there is a directed path from <i>u</i> to <i>v</i>. In addition, a digraph ... is said to have a ... root ... if every vertex ... is reachable from <i>r</i>, i.e. if there is a directed path from <i>r</i> to <i>v</i>. A digraph is called a ... directed tree if it has a root and if the underlying (undirected) graph is a tree. That is, it must morphologically look like a tree, and the structure imposed by the directional arrows must flow ... from the root. If <i>H</i> is a subgraph of a digraph <i>G</i>, then <i>H</i> is said to be a ... directed spanning tree of <i>G</i> if <i>H</i> is a directed tree and <i>H</i> contains all vertices of <i>G</i>. This is a direct analog of the concept of spanning trees for undirected graphs. Note that if <i>r</i> is the root of <i>H</i>, then <i>r</i> is clearly a root of <i>G</i>. Also, if <i>r</i> is any root of <i>G</i>, it is possible to construct a directed spanning tree of <i>G</i> with root <i>r</i>: construct <i>H</i> edge by edge starting from <i>r</i>. At each vertex, add any edge from <i>G</i> whose terminus is a vertex not yet in <i>H</i>. Since <i>r</i> is a root of <i>G</i>, this process is guaranteed to include each vertex in <i>G</i>; since we are choosing at each step only vertices not yet visite
344. complete binary tree
• date - 2002-03-08
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/CompleteBinaryTree.html
• description - A ... complete binary tree is a binary tree with the additional property that every node must have exactly two ... if an internal node, and zero children if a leaf node. More precisely: for our base case, the complete binary tree of exactly one node is simply the tree consisting of that node by itself. The property of being ... is preserved if, at each step, we expand the tree by connecting exactly zero or two individual nodes (or complete binary trees) to any node in the tree (but both must be connected to the same node.)
345. Catalan numbers
• date - 2006-11-03
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/CatalanNumbers.html
• description - The ... Catalan numbers , or ... Catalan sequence , have many interesting applications in combinatorics. The <i>n</i>th Catalan number is given by: ... %Unnecessary ... %or, recursively, % ... where ... represents the binomial coefficient. The first several Catalan numbers are <i>1</i>, <i>1</i>, <i>2</i>, <i>5</i>, ... , ... , ... , ... , ... , ... , ... (see OEIS sequence http://www.research.att.com/cgi-bin/access.cgi/as/njas/sequences/eisA.cgi?Anum=000108 for more terms). The Catalan numbers are also generated by the recurrence relation % ... % ... % ... % ... For example, ... , ... , etc. The ordinary generating function for the Catalan numbers is ... Interpretations of the <i>n</i>th Catalan number include: ... The number of ways to arrange <i>n</i> pairs of matching parentheses, e.g.: ... The number of ways a convex polygon of ... sides can be split into <i>n</i> triangles. ... The number of rooted binary trees with exactly ... leaves. ... %The first few Catalan numbers are: % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... % ... The Catalan sequence is named for Eug\`ene Charles Catalan, but it was discovered in~1751 by Euler when he was trying to solve the problem of subdividing polygons into triangles. ...
346. Aronszajn tree
• date - 2006-06-24
• creator -
• provider - NSDL OAI Repository
• location - http://planetmath.org/encyclopedia/Aronszajn.html
• description - A kappa- TreeSetTheoretic <i>T</i> for which ... for all ... and which has no cofinal branches is called a ... kappa-Aronszajn tree . If ... then it is referred to simply as an Aronszajn tree. If there are no kappa-Aronszajn trees for some kappa then we say kappa has the ... tree property . omega has the tree property, but no singular cardinal has the tree property.
347. The use of decision trees to empower production technicians to troubleshoot routine process and equipment problems
• date - 2005-08-18T15:27:58Z
• creator - Lambert, Shawn P. (Shawn Patrick)
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/10946
• description - Includes bibliographical references (p. 111).
348. Generation and termination of binary decision trees for nonparametric multiclass classification S. Gelfand, S.K. Mitter.
349. Asymptotic analysis of lattices and tournament score vectors.
• date - 2005-08-04T15:40:30Z
• creator - Winston, Kenneth James
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/15997
• description - MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
350. Reference tree networks : virtual machine and implementation
351. Distributed construction of energy-efficient ad hoc wireless broadcast trees
• date - 2005-05-19T14:46:35Z
• creator - Ahluwalia, Ashwinder S. (Ashwinder Singh), 1979-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/16828
• description - M.Eng.
352. Pose estimation using cascade trees
• date - 2005-06-02T19:30:52Z
• creator - Sundberg, Patrik P. (Patrik Per), 1980-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/17985
• description - by Patrik Sundberg.
353. A distributed algoritm for minimum weight directed spanning trees
354. Machine learning at the operating room of the future : a comparison of machine learning techniques applied to operating room scheduling
• date - 2005-09-26T20:08:13Z
• creator - Davies, Samuel Ingraham, 1980-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/28379
• description - Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.
355. Managing flexibility in the supply chain
• date - 2005-09-27T17:05:13Z
• creator - Taylor, James B. (James Boyd), 1975-
• provider - NSDL OAI Repository
• location - http://hdl.handle.net/1721.1/28571
• description - Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2003.
356. Bibliomining for Automated Collection Development in a Digital Library Setting: Using Data Mining to Discover Web-Based Scholarly Research Works
• date - 2003-12-01
• creator - Nicholson, Scott
• provider - NSDL OAI Repository
• location - http://dlist.sir.arizona.edu/625/
• description - This research creates an intelligent agent for automated collection development in a digital library setting. It uses a predictive model based on facets of each Web page to select scholarly works. The criteria came from the academic library selection literature, and a Delphi study was used to refine the list to 41 criteria. A Perl program was designed to analyze a Web page for each criterion and applied to a large collection of scholarly and non-scholarly Web pages. Bibliomining, or data mining for libraries, was then used to create different classification models. Four techniques were used: logistic regression, non-parametric discriminant analysis, classification trees, and neural networks. Accuracy and return were used to judge the effectiveness of each model on test datasets. In addition, a set of problematic pages that were difficult to classify because of their similarity to scholarly research was gathered and classified using the models. The resulting models could be used in the selection process to automatically create a digital library of Web-based scholarly research works. In addition, the technique can be extended to create a digital library of any type of structured electronic information.
357. Fungi Help Reduce Transplant Failures at the Roots
• date -
• creator - Donald Marx
• provider - NSDL OAI Repository
• location - http://americancityandcounty.com/mag/government_fungi_help_reduce/
• description - This news article reports that inoculating trees with mycorrhizal fungi prior to or at planting has revolutionized the reforestation of mined lands and similar projects. The fungi form a kind of secondary root on the seeding roots and provide soil nutrients to the plants. The page features internal links to American Town and County, including the Weekly Snapshot winner and recent articles from Chief Marketer.
358. Microbial Populations in Ocean Floor Basalt: Results from ODP Leg 187
• date -
• creator - Proceedings of the Ocean Drilling Program, Scientific Results
• provider - NSDL OAI Repository
• location - http://www-odp.tamu.edu/publications/187_SR/VOLUME/CHAPTERS/203.PDF
• description - This Ocean Drilling Program scholarly article describes results of a study of microbial populations in samples of basalt drilled from the north of the Australian Antarctic Discordance (AAD) during Ocean Drilling Program Leg 187. Samples were studied using deoxyribonucleic acid (DNA)-based methods and culturing techniques. The results showed the presence of a microbial population characteristic for the basalt environment. The article features figures of phylogenetic trees and DGGE gels.
359. Morphological character evolution and molecular trees in sepiids (Mollusca: Cephalopoda): is the cuttlebone a robust phylogenetic marker?
• date - 2006-09
• creator - BONNAUD, LAURE
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1095-8312.2006.00664.x
• description - The sepiids are characterized by their cuttlebone or sepion, an internal shell resulting from secondary mineralization of a chitinous ‘gladius’. The various species are identified using a combination of shell criteria and ‘soft-part’ characters. Using mitochondrial genes, we established phylogenetic relationships of sepiids including the three accepted genera (Sepia, Sepiella, Metasepia) and a species complex of uncertain status (Doratosepion). We showed the Sepia genus to be paraphyletic and found no direct correlation between geographical distribution and systematics. We mapped, on the molecular tree, shell characteristics commonly used as reliable diagnostic criteria for taxonomy. Due to the plasticity of the shell, these characters did not appear phylogenetically informative. In an attempt to define systematic categories related to phylogenetic relationships, new clear synapomorphies need to be established for each genus, necessitating a revision of the genus Sepia. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 139–150.
360. Phylogeographical patterns and genetic diversity in three species of Eurasian boreal forest beetles
• date - 2007-06
• creator - PAINTER, JODIE N.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1095-8312.2007.00797.x
• description - Many species that occur in formerly glaciated areas of Fennoscandia have reached their current ranges from glacial refugial areas in Eurasia. Little is known of the refugia and postglacial colonization routes of insect species that are confined to boreal forests. Here, we investigate the phylogeography of three species of saproxylic beetles distributed across Eurasia: two rare boreal forest specialists, Pytho kolwensis and Pytho abieticola, and a common, less specialized species, Pytho depressus. In all species, there were two well-defined haplotype clades based on 645 bp of cytochrome oxidase subunit I gene sequence. In each species one clade was found only in China. The other clade occurred from China to north-western Europe in both P. kolwensis and P. depressus, but was apparently absent from China in P. abieticola. In spite of common phylogeographical patterns, the distribution of genetic variation differed markedly between the three species. In P. kolwensis, a highly-threatened species in old-growth forests in Fennoscandia, there was an extremely low level of genetic variation throughout Eurasia. One common haplotype, represented by 86% of the samples, dominated in all sampling localities. Levels of genetic variation were higher in both P. abieticola and P. depressus, with 31% and 58%, respectively, of the samples representing a unique haplotype. In each species, relationships between haplotypes were not well resolved, and haplotypes from one sampling locality were generally not clustered in either Neighbour-joining trees or statistical parsimony networks. These patterns in the distribution of genetic variation can be attributed to differences in the species’ population sizes, ecologies, glacial refugial areas, and postglacial colonization dynamics. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 267–279.
361. Phylogenetic analysis of Nymphaeales using fast-evolving and noncoding chloroplast markers
• date - 2007-06
• creator - LÖHNE, CORNELIA
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1095-8339.2007.00659.x
• description - The Nymphaeales (water-lilies and relatives) represent one of the earliest branching lineages of angiosperms and comprise about 70 aquatic species. Here, we present a comprehensive study of phylogenetic relationships within the Nymphaeales from a dataset containing 24 representatives of the order, including all currently recognized genera and all subgenera of the genus Nymphaea, plus 5 outgroup taxa. Nine different regions of the chloroplast genome − comprising spacers, group II introns, a group I intron, and a protein coding gene − were analysed. This resulted in a character matrix of 6597 positions and an additional 369 characters obtained from coded length mutations. Maximum parsimony and Bayesian analyses of the complete dataset yielded congruent, fully resolved and well-supported trees. Our data confirm the monophyly of the Cabombaceae but do not provide convincing support for the monophyly of Nymphaeaceae with respect to Nuphar. Moreover, the genus Nymphaea is inferred to be paraphyletic with respect to Ondinea, Victoria and Euryale. In fact, the Australian endemic Ondinea forms a highly supported clade with members of the Australian Nymphaea subgenus Anecphya. In addition, Victoria and Euryale are inferred to be closely related to a clade comprising all night-blooming water-lilies (Nymphaea subgenera Hydrocallis and Lotos). An experimental approach showed taxon sampling to be of influence on the nodes reconstructed in core Nymphaeaceae. The results underscore that more diverse genera, if not clearly known to be monophyletic, should be represented by all major lineages. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154, 141–163.
362. Patterns of allozyme variation in western Eurasian Fagus
• date - 2007-06
• creator - GÖMÖRY, DUŠAN
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1095-8339.2007.00666.x
• description - Fagus sylvatica L. is one of the most widespread broad-leaved trees in the temperate forests of the northern hemisphere. In addition to two subspecies, F. sylvatica ssp. sylvatica in Europe and F. sylvatica ssp. orientalis in south-western Asia, two further taxa were described: F. moesiaca (Maly) Czeczott in the south-western Balkans and F. taurica Popl. in Crimea. The opinions about the number and ranks of taxa within this complex are highly controversial. To assess the degree of genetic differentiation among them, and to reveal geographical patterns of genetic diversity and their relationships to history and biogeography of beech populations, genetic variation at 12 allozyme loci was studied in 279 populations in western Eurasia. A Bayesian analysis of population structure revealed the existence of two clusters, which fairly well coincided with F. sylvatica ssp. sylvatica and F. sylvatica ssp. orientalis, whereby the populations from the south-western Balkans and Crimea contained a mixture of these two gene pools. On the other hand, a neighbour-joining tree based on pairwise FST failed to separate the subspecies into well-defined distinct clades. Populations of F. sylvatica ssp. orientalis proved to be incomparably more differentiated than ssp. sylvatica (FST = 0.157 and 0.032, respectively). Asian populations also showed higher levels of allelic richness both on population and taxon levels than the European ones (the number of alleles after rarefaction was 3.40 and 4.27 in F. sylvatica ssp. sylvatica and ssp. orientalis, respectively). This indicates that the gene pool of F. sylvatica ssp. orientalis has not been depleted by reduced population sizes during the Pleistocene glaciations, as is the case of F. sylvatica ssp. sylvatica. Genetic similarities between isolated regional populations are explained by shared ancestral polymorphisms and/or range overlaps with subsequent hybridization in the past. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154, 165–174.
363. Responses to Fire in Selected Tropical Dry Forest Trees 1
• date - 2006-09
• creator - Otterstrom, Sarah M.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2006.00188.x
364. Explaining Leaf Herbivory Rates on Tree Seedlings in a Malaysian Rain Forest
• date - 2007-05
• creator - Eichhorn, Markus P.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1744-7429.2007.00264.x
• description - ABSTRACT Seedlings of five species of dipterocarp trees were planted in experimental plots in rain forest gaps in Sabah, Malaysia, and the rates of herbivory on their mature leaves recorded over 6 mo. A novel method was used to estimate the feeding pressure exerted by the local insect herbivore community, derived from the relative abundances of the dominant generalist herbivores and their feeding preferences. Characteristics of the leaves related to their defense and nutritional value were measured—phenolic content, laminar fracture toughness, laminar thickness, and nitrogen content. Three main groups of herbivorous insects were present—coleopteran and lepidopteran herbivores, which were sampled by hand from the seedlings, and orthopteran herbivores, which were sampled by sweep netting. The feeding preferences of the main coleopteran and orthopteran herbivores were determined using laboratory feeding trials. Combining variables in a Principal Components Analysis, a clear separation was found between the five seedling species along the first extracted component. This correlated closely with herbivory rates between species. The first extracted component comprised a negative influence of phenolic content and positive effects of nitrogen content, laminar fracture toughness, abundances of coleopteran and lepidopteran herbivores, and estimated feeding pressure of the coleopteran community. Further studies are required to determine the potential applications of the latter measure of estimated herbivore community impact.
365. Environmental Science Activities for the 21st Century
• date -
• creator -
• provider - NSDL OAI Repository
• location - http://esa21.kennesaw.edu/activities/activities.htm
• description - The Environmental Science Activities for the 21st Century (ESA21) project provides multi-week activity modules around major topics in environmental science. The modules are designed to supplement environmental science courses with existing laboratory components or provide course activities for traditional and online courses that lack a laboratory component. The activities hybridize online and wet-lab exercises to take advantage of both formats and utilize existing, high-quality materials from the Internet. The modules emphasize lifestyle examination, ethical considerations and critical analysis of individual contributions to large-scale regional and global impacts. This allows students to see their place in the environment and how lifestyle changes can facilitate greater environmental sustainability. Modules cover the atmosphere, basic science, biogeochemical cycles, energy, fossil fuels, nuclear energy, ozone, renewable energy and water.
366. 1948: Reel 2: British Guiana
• date - 1948-00-00T00:00:00Z
• creator - Watson Kintner
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Field. Small boy bathing at well or over stream. Building: arched facade. Church. Wooden frame building with square tower. Narrow canal. People. Large wooden vat with iron rings. Wide canal, tree-lined avenue. Scenes in town. Twin stone towers, large sphere (?) on top. Spoked wheel at a well ( ? ). Dragonflies in flight, [out of focus] Scenes in town: tall wooden tower, possibly a light house; flowering bush; train station (?); cart on road; telephone booth. Oddly ropy trees. Carved stone posts in a yard. Black man wearing picket sign: "WE WANT. . " Lumber yard. Half-built wooden building. Boats: one with straw-roofed cabin. City scenes. Child's toy car. City scenes: "Chinese Association" building, "Police Headquarters." Food for sale. Bicyclists. Wooden Women working in flooded field. Birds and sea lions. Fan-palm tree. Grove. Fields with scattered buildings. Barges, sailboats, canals. Many views ot* riverbank from passing boats. Wooden house: thatched roof. Paddle boats. Boat with tiller and crude sail. More scenes along river.
367. 1950: Reel 1: Peru. July 25-26
• date - 1950-00-00T00:00:00Z
• creator - Watson Kintner
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - 1950: Reel 1: Peru. July 25-26 Lima. Cajamarquillo. Ghocico? Miraflores. Pachacamac. Market. Donkey with milk cans. Market prices on tower. Mats, [stacked outside hut] Old Inca rivers south of Lima. Adobe steps and rivers. Mountains in background. Inca burial vaults; clay-lined pits. Bones in vaults. Line near base of mountain possibly ancient Inca canal built to carry water from mountain. Market. Machine for shaving ice; market, [some dark--3:59] Hobby museum built by natives on hill containing articles such as a streetcar, clay dog, clay pots. Fig trees, homes around Chocico. Modern stone-carved buildings, [perf.] Bougainvillea. (Pachacamac) 25 miles south of Lima. Paintings on walls. Piece of plaster upended to show edge and thickness. Green and red plaster. Inca stonework forming trench. More ruins. Walls bored by worms. Cacti. Pyramid. Inca stone wall, [cu of masonry] Ocean (looks like pavement). Rectangular wall on ground. Characteristic irregular stones. Inca masonry. Ruins. Skull with cracked head. [mws--piece missing along left frontalâ¦] Building. Sunset. Lima. Monastery courtyard. Statue of Mary. Spanish bridge. Building. Old coach. Bathtub of stone. Carriage. Building.
368. TS17PMECHANISMS OF INJURY CAUSING LIMB FRACTURES WITHIN THE PAEDIATRIC POPULATION
• date - 2007-05
• creator - N gui , N. K.
• provider - NSDL OAI Repository
• location - http://www.blackwell-synergy.com/doi/abs/10.1111/j.1445-2197.2007.04133_17.x
• description - Objective  Playground and sporting accidents account for a large percentage of paediatric injuries, yet they are largely preventable. The aim of this study is to investigate the risk factors and mechanisms associated with upper and lower limb fractures in children. Method  145 children admitted to a regional Australian hospital (Coffs Harbour Base Hospital) totalling 207 upper and lower limb fractures over an 12 month period between January 1st 2004 to December 31st 2004 were identified from the hospital medical records database. Retrospective analysis was performed on demographic data, fracture type and mechanisms causing the fracture. Results  Males accounted for 69.7% of all childhood limb fractures. 77.7% of all fractures were upper limb, while 22.3% were lower limb. The leading causes of lower limb fractures were football injuries, push bike accidents, and aquatic accidents, accounting for 51.8% of all lower limb fractures. Monkey bars, swings, trees, skateboard and scooter accidents were associated with a relatively high prevalence of upper limb injuries when compared to other injury mechanisms. Football, push bike and skateboard accidents alone accounted for 40.6% of fractures in our male patients. This figure was only 4.5% in our female patients, and in general, the causes of fractures in females are more evenly distributed. Conclusion  Limb fractures in children have a diverse range of causes, but specific fractures occur more frequently in particular sexes and with certain activities. There is a role for further injury prevention targeting specific high risk groups and activities.
369. Extreme Waves
• date -
• creator - Craig B. Smith
• provider - NSDL OAI Repository
• location - Washington DC. National Academy Press, 2006
• description - Waves are hypnotic and beautiful. They can also be great fun. But Hurricanes Katrina and Rita taught us that they can be powerful and deadly while the 2004 tsunami proved that some waves are absolutely devastating. Science is the best tool for understanding and predicting the most extreme waves. Where do waves come from? Why are some big and some small? From winter to summer, the nature of the beach changes, sculpted by the tireless energy of waves. Most waves are simply rhythmic expressions of Earth&s movement through space and the changes they bring to our shorelines are gradual. But given the right weather conditions and combination of natural forces, waves can wreak havoc. These are extreme waves, waves that can stretch 100-feet high&posing an imminent threat to large sea vessels and coastal structures. There are even waves that have stripped trees from mountains as they surged to an estimated 1,700 feet high. But even smaller waves are dangerous to ships and coastlines. Indeed, the lessons of the 2004 Bay of Bengal tsunami and the damage wrought by recent tidal surges in New Orleans underscore the need for better tracking and prediction of extreme waves. Extreme Waves is a fascinating history of waves. Covering both the headline stories as well as incidents that are less well-known but equally startling Craig Smith, author and amateur sailor, will have you riveted from the first chapter to the last.
370. Forest Trees
• date -
• creator - National Research Council
• provider - NSDL OAI Repository
• location - Washington DC. National Academy Press, 1991
• description - News reports concerning decline of the world's forests are becoming sadly familiar. Most losses are measured in square kilometers, but a more profound loss cannot be measured. As forests disappear, so do their genetic resources. The genes they possess can no longer aid in their adaptation to a changing environment, nor can they be used to develop improved varieties or products.This book assesses the status of the world's tree genetic resources and management efforts. Strategies for meeting future needs and alternatives to harvesting natural forests are presented. The book also outlines methods and technologies for management, evaluates activities now under way, and makes specific recommendations for a global strategy for forest management.
371. Proceedings of a Symposium
• date -
• creator - National Research Council
• provider - NSDL OAI Repository
• location - Washington DC. National Academy Press, 1997
• description - The United States produces 25% of the world's wood output, and wood supports a major segment of the U.S. industrial base. Trees provide fiber, resins, oils, pulp, food, paper, pharmaceuticals, fuel, many products used in home construction, and numerous other products. The use of wood as a raw material must consider production efficiencies and natural resource conservation as well as efficient, profitable use of solid wood, its residues, and by-products.To better assess the use of wood as a raw material, the U.S. Department of Agriculture's Forest Service asked the National Research Council's Board on Agriculture to bring together experts to review the analytical techniques used to follow the life-cycle of wood production--from tree to product--and assess the environmental impacts. This resulting book provides a base of current knowledge, identifying what data are lacking, where future efforts should be focused, and what is known about the methodologies used to assess environmental impacts. The book also focuses on national and international efforts to develop integrated environmental, economic, and energy accounting methologies.
372. Expanding the National Economic Accounts to Include the Environment
• date -
• creator - National Research Council
• provider - NSDL OAI Repository
• location - Washington DC. National Academy Press, 1999
• description - In order to really see the forest, what's the best way to count the trees? Understanding how the economy interacts with the environment has important implications for policy, regulatory, and business decisions. How should our national economic accounts recognize the increasing interest in and importance of the environment?Nature's Numbers responds to concerns about how the United States should make these measurements. The book recommends how to incorporate environmental and other non-market measures into the nation's income and product accounts.The panel explores alternative approaches to environmental accounting, including those used in other countries, and addresses thorny issues such as how to measure the stocks of natural resources and how to value non-market activities and assets. Specific applications to subsoil minerals, forests, and clean air show how the general principles can be applied.The analysis and insights provided in this book will be of interest to economists, policymakers, environmental advocates, economics faculty, businesses based on natural resources, and managers concerned with the role of the environment in our economic affairs.
373. Life, Energy, and the Unity of Nature
• date -
• creator - John Whitfield
• provider - NSDL OAI Repository
• location - Washington DC. National Academy Press, 2006
• description - For centuries, scientists have dreamt of discovering an underlying unity to nature. Science now offers powerful explanations for both the dazzling diversity and striking similarities seen in the living world. Life is complicated. It is truly the &entangled bank& that Charles Darwin described. But scientists are now discovering that energy is the unifying force that joins all life on Earth. Visionary biologists have advanced a new theory that explains how the natural world&from the tiniest amoeba to the greatest rain forest&is constructed, providing a fresh perspective on the essential interconnectivity of living systems. This revolutionary theory explains a variety of phenomena&helping us understand why a shrew eats its bodyweight in food each day, why a mammal&s heart beats about 1 billion times in its lifetime, why there are no trees as tall as the Eiffel Tower, and why more species live at the Earth&s equator than at its poles. By looking at how living things use energy, we can answer these and myriad other intriguing questions. In the Beat of a Heart combines biography, history, science and nature writing to capture the exciting advances& and the people who are making them&that are triggering a revolution as potentially important to biology as Newton&s insights were to physics.
374. Checklist of the woody cultivated plants of Florida [electronic resource] / Derek Burch, Daniel B. Ward [and] David W. Hall.
• date - [1988]
• creator - Burch, Derek George, 1942-
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/UF00000139.pdf
• description - Electronic reproduction. [Florida] : State University System of Florida, PALMM Project, 2001. Mode of Access: World Wide. System Requirements: Internet connectivity; Web browser software; Adobe Acrobat Reader to view and print PDF files. Electronically reproduced from Collection in George A. Smathers Libraries at the University of Florida.
375. Florida bird life [electronic resource] / by Arthur H. Howell, color plates from original paintings by Francis L. Jaques.
• date - 1932
• creator - Howell, Arthur H. (Arthur Holmes), 1872-1940.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/UF00000111.pdf
• description - Electronic reproduction. [Florida] : State University System of Florida, PALMM Project, 2001. Mode of Access: World Wide Web. System requirements: Internet connectivity; Web browser software; Adobe Acrobat Reader to view and print PDF files. Electronically reproduced from collection in George A. Smathers Libraries of the University of Florida.
376. Photographs depicting plants in the Everglades, 1921-1931? [electronic resource]
• date - 1921-1931?
• creator - Matlack, Claude Carson, 1878-1944.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTCM00500032.jpg
• description - Electronic reproduction. Miami, Fla. : Reclaiming the Everglades, c2000. Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software. Digitized from photographs held by the Historical Museum of Southern Florida, Miami.
377. Photographs depicting a trip to bird rookeries on Whitewater Bay, June 12, 1931. [electronic resource]
• date - 1931
• creator - Matlack, Claude Carson, 1878-1944.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTCM00500014.jpg
• description - Electronic reproduction. Miami, Fla. : Reclaiming the Everglades, c2000. Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software. Digitized from photographs held by the Historical Museum of Southern Florida, Miami, Florida.
378. Photographs depicting New River (Broward County, Fla.), 1920-1928. [electronic resource]
• date - 1920-1928
• creator - Matlack, Claude Carson, 1878-1944.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTCM00170001.pdf
• description - Electronic format produced as part of Reclaiming the Everglades, a collaborative project of the University of Miami, Florida International University, and the Historical Museum of Southern Florida, funded by the Library of Congress/Ameritech National Digital Library Program.
379. Photographs depicting Royal Palm State Park, 1920-1929. [electronic resource]
• date - 1920-1929
• creator - Matlack, Claude Carson, 1878-1944.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTCM00500001.jpg
• description - Electronic format produced as part of Reclaiming the Everglades, a collaborative project of the University of Miami, Florida International University, and the Historical Museum of Southern Florida, funded by the Library of Congress/Ameritech National Digital Library Program.
380. The Everglades and other essays relating to southern Florida [electronic resource] / by John Gifford.
• date - [c1911].
• creator - Gifford, John Clayton, 1870-1949.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTPU00050001.jpg
• description - Electronic format produced as part of Reclaiming the Everglades, a collaborative project of the University of Miami, Florida International University, and the Historical Museum of Southern Florida, funded by the Library of Congress/Ameritech National Digital Library Program.
381. Excerpts from Tropic magazine. [electronic resource]
• date - 1916
• creator -
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTEP00040004.jpg
• description - Electronic reproduction. Miami, Fla. : Reclaiming the Everglades, c2000. Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software. Digitized from magazine at the Historical Museum of Southern Florida, Miami, Florida.
382. Musa Isle Fruit Farm (Miami), 1898-1905. [electronic resource]
• date - 1898-1905
• creator -
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTVM00010003.pdf
• description - Electronic format produced as part of Reclaiming the Everglades, a collaborative project of the University of Miami, Florida International University, and the Historical Museum of Southern Florida, funded by the Library of Congress/Ameritech National Digital Library Program.
383. Age of cavity trees and colony stands selected by Red-cockaded Woodpeckers.
• date -
• creator - Field, R.
• provider - NSDL OAI Repository
• location -
• description - Includes data from Apalachicola Natl. Forest. 92-97.
384. Letter from J. E. Moseley, July 29, 1921. [electronic resource]
• date -
• creator - Willson, James Mallory.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTMW00350001.pdf
• description - Discusses drainage canal between Lake Apopka and Tahopkulega, and timber tracts near Lake Okeechobee.
385. Correspondence relating to Tamiami Trail, Ochopee and Collier County, 1930-1936. [electronic resource]
• date -
• creator - Jaudon, James Franklin, 1873-1938.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTJJ00110009.pdf
• description - Electronic format produced as part of Reclaiming the Everglades, a collaborative project of the University of Miami, Florida International University, and the Historical Museum of Southern Florida, funded by the Library of Congress/Ameritech National Digital Library Program.
386. The distribution and character of natural habitats in pre-settlement northern Florida, as recorded by public land survey records [electronic resource] / Mark W. Schwartz, Joseph Travis.
• date - [1995]
• creator - Schwartz, Mark W.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/UF00000501.jpg
• description - Electronic reproduction. [Florida] : State University of System of Florida, PALMM Project, 2003. Mode of Access: World Wide. System Requirements: Internet connectivity; Web browser software; Adobe Acrobat Reader to view and print PDF files. Electronically reproduced from Collection in George A. Smathers Libraries at the University of Florida.
387. Trees, Shrubs, and Woody Vines of Northern Florida and Adjacent Georgia and Alabama.
• date - 1988
• creator - Godfrey, R.K.
• provider - NSDL OAI Repository
• location -
• description -
388. Top-Working Pecan Trees
• date - 1924
• creator - Blackmon, G. H.
• provider - NSDL OAI Repository
• location -
• description -
389. Transplanting Peach Trees
• date - 1939
• creator - Blackmon, G. H.
• provider - NSDL OAI Repository
• location -
• description -
390. Transplanting Pecan Trees
• date - 1923
• creator - Blackmon, G. H.
• provider - NSDL OAI Repository
• location -
• description -
391. Transplanting Pecan Trees
• date - 1926
• creator - Blackmon, G. H.
• provider - NSDL OAI Repository
• location -
• description -
392. Correspondence relating to rubber industry in South Florida, 1918-1924. [electronic resource]
• date -
• creator - Model Land Company.
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/RTML00280681.pdf
• description - The proposed rubber plantations never became established. Ficus elastica is native to India and Asia.
393. Contribution of bark to fire resistance of southern trees.
• date -
• creator - Hare, R.C.
• provider - NSDL OAI Repository
• location -
• description -
394. Survival of trees after low-intensity surface fires in Great Smoky Mountains National Park.
• date -
• creator - Harmon, M.E.
• provider - NSDL OAI Repository
• location -
• description -
395. Beautifying the home with trees, shrubbery and lawns.
396. Landscape plants for Florida homes [electronic resource] / by John V. Watkins.
• date - [1963]
• creator - Watkins, John V. (John Vertrees)
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/uf00002887.pdf
• description - Sound principles in the use of plants are the same whether one lives in Miami or Minneapolis, Tallahassee or Topeka, whether one's property is large or small, whether the exposure is north or south. It is true that the kinds of plant marerials will vary with region and the spirit of no two gardens will be identical, but fundamental concepts of good planning are the same regardless of locale.
397. Landscape plants for Florida homes [electronic resource] / by John V. Watkins.
• date - [1950]
• creator - Watkins, John V. (John Vertrees)
• provider - NSDL OAI Repository
• location - http://purl.fcla.edu/fcla/dl/UF00002888.pdf
• description - Electronic reproduction. [Florida] : State University System of Florida, PALMM Project, 2002. (Florida Agricultural History and Rural Life) Mode of access: World Wide Web. System requirements: Internet connectivity; Web browser software; Adobe Acrobat Reader to view and print PDF files. Electronically reproduced from collection in the George A. Smathers Libraries of the University of Florida.
398. Diversity of canopy trees in a neotropical forest and implications for conservation.
• date - 1983
• creator - Hubbell, S.P.
• provider - NSDL OAI Repository
• location -
• description -
399. Common Trees Of South Florida
• date - 1930
• creator - Florida Forest and Park Service
• provider - NSDL OAI Repository
• location -
• description -
400. Floridan Keys With Special Reference To Soil Productivity
• date - 1935
• creator - Gifford, John C.
• provider - NSDL OAI Repository
• location -
• description - Reprinted in 1938, 1940, 1946. Includes information on geography, soils, home construction, fruits and trees grown on the keys, and early settler life on the keys.
401. Cottony cushion scale [electronic resource] / by J.R. Watson.
402. Dermal absorption of a dilute aqueous solution of malathion [electronic resource] / by John E Scharf.
403. Tropical Ecosystem Environment observations by Satellite
• date - 2005-08
• creator - Tropical Ecosystem Environment Observations by Satellite
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=0B5C8530-8A7E-4005-913D-611C44034841
• description - A large-scale project initiated by the European Commission in the early 1990?s, the TREES (Tropical Ecosystem Environment observations by Satellite) project is dedicated to the development of techniques for global tropical forest inventory using satellite imagery. One of the objectives was to create maps to document the extent of dense tropical forest on a continental scale. Mapping dense humid forest, fragmented forest and non-forest make it possible to identify deforestation hot spots. Reliable analysis of satellite radar images is limited by a lack of appropriate field observations. In particular, the useful parameters for radar signal modeling are quite specific and are not available in the ecological literature. To solve this problem it was decided to collect a series of parameters about the different types of forests, such as open forest, closed forest, or swamp forest.
404. Project Links: graph theory, industrial drilling
• date - 2001-08
• creator - RPI Project Links
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=0F488077-4FD3-4F23-AD05-BF2B9F8E4511
• description - This module is designed to teach students to solve graph-theory related problems (a gang-drill example is given) and explore its applications in many diverse fields. Subjects covered in the module are: * what is a graph? * edges and vertices * a first theorem * types of graphs * subgraphs and supergraphs * walks, paths, cycles * trees * independent sets, cliques, etc. * vertex coloring * modeling it as a graph theory problem * first lower bound * the inside view * a good coloring * the best coloring Keywords: Operations Research, mathematics, graph theory, theory, computer science
405. Introduction to Data Structures
• date - 2007-04
• creator - Osman Balci
• provider - NSDL OAI Repository
• location - http://www.needs.org/needs/?path=/public/search/search_results/learning_resource/summary/index.jhtml&id=17BEFD1C-BF52-417E-98D2-9582AF0C7662
• description - Introduces the topic of data structures by comparing how data is actually stored in a computer with the abstract structures that programmers use. To illustrate this comparison, several basic data structures such as lists, stacks, and queues are described. Each lesson includes a set of review questions which test the important concepts from the lesson and provide practice problems. After reading each lesson, you should work the review questions before proceeding to the next lesson. Use the navigation bar at the top of this page to view the lessons and access the review questions. Each lesson page has a link on the navigation bar which will take you to the review questions for that lesson. Lessons: 1. Introduction to Data Structures 2. Computer Memory 3. Pointers and Indirection 4. Linear Data Structures 1. Ordered List: The Abstract View 2. Ordered List: The Implementation View 3. Stacks: The Abstract View 4. Stacks: The Implementation View 5. Queues: The Abstract View 6. Queues: The Implementation View 5. Nonlinear Data Structures 1. Multidimensional arrays 2. Trees 3. Graphs 6. Abstract Data Types 7. Summary.
406. Discrete Structures Syllabus
• date - 2007-06
• creator - Fletcher Norris
• provider - NSDL OAI Repository
• location - http://www.needs.org/needs/?path=/public/search/search_results/learning_resource/summary/index.jhtml&id=1CC0592D-43CC-4A95-A054-889B6966313F
• description - Course website (with lectures, homework, syllabus, and practice quizzes) for "a course in discrete structures with an emphasis on applications to computer science. A basic understanding of discrete mathematical topics is fundamental for academic work in computer science. Many students of this course will find they have familiarity with some of the topics: for instance, truth tables, logical propositions, elements of set theory, as well as basic notions of functions and mathematical induction. Prior work in these areas is not assumed. In this course we will discover that logical propositions are the underlying model of discrete systems. From this modest beginning we develop algorithms and prove their efficacy. Topics include propositional and predicate logic, basic proof techniques, set algebra and Boolean algebra, recursion and induction, trees and graphs, introductory combinatorics, and matrix algebra. The knowledge gained will be extremely useful in upper level UNCW computer science classes."
407. TEACHING ENGINEERING ETHICS: A Case Study Approach
• date - 2006-12
• creator - Michael S. Pritchard Editor, pritchard@wmich.edu
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=1CFE0127-2506-4712-BD0B-D38DA476054B
• description - There are more than 30 cases that address a wide range of ethical issues that can arise in engineering practice. They are presented in alphabetical order by case name under some broad categories in terms of which many of the cases can be arranged. "However, it should be noted that many cases fall into several of these categories; and many cases raise issues for which no special category is listed below. It is best for readers to view the listings below simply as suggestive. Acknowledging Mistakes * Containers * Failure * Larom * On the Job * USAWAY Conflicts of Interest * Condo * Golfing * Inside Tool & Die * Last Resort * On the Job * Parkville * Research Opportunity? * Shameful Waste Dissent and/or Whistleblowing * Dissent or Not Dissent * Excess * Failure * Health in the Workplace * Last Resort * Summer Forklifter * Thesis Environmental & Safety Concerns * Containers * Dissent or Not Dissent * Excess * Health in the Workplace * Job Search * On the Job * Parkville * Shameful Waste * Summer Forklifter * Tourist Problem * Trees * Vacation * Waste Disposal Honesty and Truthfulness * Containers * Co-op Student * Deadline * Larom * Excess * Failure * Golfing * Job Search * Last Resort * Price is Right? * Thesis * Tourist Problem * USAWAY * Vacation * Waste Disposal Organizational Communication * Borrowed Tools * Containers * Deadline * Dissent or Not Dissent * Excess * Failure * Last Resort * Layoffs * On the Job * Sunnyvale * Waste Disposal * Whose Property? Ownership * Borrowed Tools * Whose Property? Quality Control and Product Liability * Containers * Deadline * Failure * Larom
408. Decision Tree Analysis
409. Frog Island
• date - 1998-11
• creator - Parvati Dev
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=2921CFDD-3BA7-4191-A745-4B385A1BE9C0
• description - Frog Island is an environment where students explore a 3D virtual outdoor habitat and visit various "huts" to learn about topics such as anatomy, physiology (digestion, respiration, circulation), and biomechanics. They have a workbook to outline the various lessons and allows them to enter observations, raise questions or enter answers to questions posed. There is a supplementary window where relevant text, images and videos can be displayed. To facilitate unstructured learning modes, students are encouraged to explore the virtual environment, interacting and noting any observations they may care to make. When a student has finished her lesson plans, she can produce a web document that summarizes her progress, the places she has visited and the annotations she has made along the way. This summary will be made available to her teachers, who are then free to post them to the web at the appropriate time. The virtual habitat resembles a natural setting with ponds, grass, trees and meadows. There are various theme-based activity huts and regions that provide students with the resources needed to complete their lesson plans and activities. The following huts have been identified for the initial Frog Island environment: Orientation Problem statement [for theme-based teaching] Diversity and Habitat -Genetic diversity -Adaptation -Concept map Organs Bones -Frog -Comparative -Microstructure Muscles -Types -Classification -Function -Lab experiments -Advanced Biomechanics -Levers -JavaFrog -Jumping frog contest Bioethics -Habitat preservation -Playing god -"good" science vs. "bad" science
410. DMTCS - Discrete Mathematics and Theoretical Computer Science
• date - 2007-06
• creator - Discrete Mathematics and Theoretical Computer Science
• provider - NSDL OAI Repository
• location - http://www.needs.org/needs/?path=/public/search/search_results/learning_resource/summary/index.jhtml&id=488A8736-C105-4E5E-8AAC-6BE33A4CFD54
• description - "DMTCS is a high standard peer-reviewed electronic journal devoted to rapid publication of innovative research which covers the fields of Discrete Mathematics and Theoretical Computer Science and puts a certain emphasis on the intersection of these two fields. Analysis of algorithms is concerned with accurate estimates of complexity parameters of algorithms and aims at predicting the behaviour of a given algorithm run in a given environment. It develops general methods for obtaining closed-form formulae, asymptotic estimates, and probability distributions for combinatorial or probabilistic quantities, that are of interest in the optimization of algorithms. Interest is also placed on the methods themselves, whether combinatorial, probabilistic, or analytic. Combinatorial and statistical properties of discrete structures (strings, trees, tries, dags, graphs, and so on) as well as mathematical objects (e.g., continued fractions, polynomials, operators) that are relevant to the design of efficient algorithms are investigated."
411. Images and Video Clips of Diesel Exhaust From Dump Trucks
• date - 2007-02
• creator - A Division Of EcoIQ.com EcoFootage.com: Promoting Sustainability with Stock Video
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=75FF20B0-B618-4001-A293-7E18DF86D285
• description - Diesel exhaust has significant human health impacts in addition to the many environmental impacts associated with all types of internal combustion engines. Diesel exhaust contains fine particulates that are inhaled increasing the risk of lung cancer, asthma, and chronic bronchitis. Dump trucks with visible exhaust emissions in heavy traffic. Close ups of diesel exhaust pipes. Shots of dump trucks being driven on a congested road with particulates visible in their diesel exhaust pipe emissions. Close up, medium, and wide shots of a chrome plated diesel exhaust pipe on a dump truck being driven slowly down a road. Shot of dual exhaust pipes on a dump truck. Shot of a dump truck passing in front of trees. This background makes its black exhaust highly visible. A dump truck with a flap on top of its exhaust pipe followed by more dump trucks. Zoom out to a congested road with a car entering and merging between dump trucks. Wide shot of a dump truck in heavy car traffic with a ?Merge? sign in the foreground.
412. Course on Visualization
• date - 2006-11
• creator - Maneesh Agrawala
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=7DA40A76-1438-4E06-B83A-FD7180690C2F
• description - Visual media in the form of diagrams, graphs, photographs, 3D renderings, sketches, animations, and film are increasingly generated, manipulated, and transmitted by computers. When well designed, such displays capitalize on human facilities for processing visual information and thereby improve comprehension, memory, inference, and decision making. Yet the digital tools for transforming data into visualizations still require low-level interaction by skilled human designers. As a result, producing effective visualizations can take hours or days and consume considerable human effort. In this course we will study techniques and algorithms for creating effective visualizations based on principles and techniques from graphic design, visual art, perceptual psychology and cognitive science. The course is targeted both towards students interested in using visualization in their own work, as well as students interested in building better visualization tools and systems. The following topics are covered: The Purpose of Visualization, Data and Image Models, Perception, Spatial Layout, Trees and Graphs, Interaction, Animation, Usability and Evaluation, Conveying Shape and Structure, Photography and Visualization. The course website links to a wiki site with lecture slides, notes, readings and homeworks.
413. Engineering Analysis
• date - 2006-12
• creator - Hugh Jack
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=814CF167-C03D-4DCD-89F9-A7CCA40B4484
• description - A book used for teaching upper level and graduate courses in engineering analysis. It is currently being used to teach EGR 600 - Analysis. This book emphasizes programming - this is not found in any other autoamtion books available. At present, half of the book is written chapters, while the other half is in note form. Course notes and slides on the following topics: * Numbers and units [PDF] * Algebra [PDF] * Trigonometry [PDF] * Vectors [PDF] * Matrices [PDF] * Graphing [PDF] * Programming [PDF] * Permutations [PDF] * Statistics [PDF] * Reliability [PDF] * Calculus [PDF] * Differential Equations [PDF] * ECE Review [PDF] * ME Review [PDF] * PDM Review [PDF] * MO Review [PDF] * Boolean [PDF] * Number Systems [PDF] * Transforms [PDF] * Geometry [PDF] * Financial [PDF] * Optimization [PDF] * Projects [PDF] * Graphs [PDF] * Trees [PDF]
414. The Unofficial LogicCoach 9 Page
• date - 2007-07
• creator - Nelson Pole
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=9F157C75-FEF3-47CD-9B40-F80AFACA196A
• description - The Official LogicCoach Page is maintained by the program's distributor, the Wadsworth Publishing Company. The program was developed by Professor Nelson Pole of the Philosophy Department at Cleveland State University who also maintains this site. LogicCoach consists of an extensive series of computer modules that cover virtually all topics taught in a college course in logic including most aspects of: Nonformal and Informal logic Basic Vocabulary Argument Diagrams Definitions Fallacies Analogies Mill's Methods Probability Traditional Logic (both with and without existential import) Categorical Propositions Standardization Syllogisms Enthymemes Sorites Venn Diagrams Symbolic Logic Translation: English to Symbols Translation: Symbols to English Logical Form Truth Tables Indirect Truth Tables Quantification Identity Proofs Trees
415. Biomass Research at NREL
• date - 2007-02
• creator - Biomass Research at NREL Batelle, U.S. Department of Energy The National Renewable Energy
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=B31FEA98-5C40-474B-8ED2-1B13392649F1
• description - "Biomass is plant matter such as trees, grasses, agricultural crops or other biological material. It can be used as a solid fuel, or converted into liquid or gaseous forms, for the production of electric power, heat, chemicals, or fuels. By integrating a variety of biomass conversion processes, all of these products can be made in one facility, called a biorefinery. NREL is working to develop cost effective, environmentally friendly biomass conversion technologies to reduce our nation's dependence on foreign oil, improve our air quality, and support rural economies. Learn more about biomass. Thumbnail cover of From Biomass to Biofuels: NREL Leads the Way document. From Biomass to Biofuels: NREL Leads the Way (PDF 977 KB) Download Adobe Reader. Biomass R&D efforts at NREL are focused on: * biomass characterization, * thermochemical and biochemical biomass conversion technologies, * biobased products development, and * biomass process engineering and analysis."
416. Climate Care - Helping you help the climate
• date - 2007-08
• creator - Climate Care
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=B92FC841-51D7-41B2-A2DC-6A080DCD1B09
• description - Website with calculators to determine offset for carbon emissions. "'Carbon Offsetting Explained' animation (website homepage) Each time we heat our homes, take a flight or drive the car, CO2 is added into the atmosphere. CO2 is a greenhouse gas that is released when fossil fuels such as oil, gas and coal are burnt. Offsetting means paying someone to reduce CO2 in the atmosphere by the same amount that your activities add. In this way you can 'neutralise' or 'balance' the CO2 added by your activities. Climate Care offsets your CO2 by funding projects around the world. These can be in: * Renewable energy &#150; this replaces non-renewable fuel such as coal * Energy efficiency &#150; this reduces the amount of fuel needed * Forest restoration &#150; this absorbs CO2 from the atmosphere as the trees grow So as well as taking steps to reduce your 'carbon footprint' you can offset what remains, helping to promote low-carbon technologies where they make the most impact."
417. Ecological Design in the 21st Century : Schumacher 2000 Lecture
• date - 2000-01
• creator - John Todd Ocean Arks Interational (OAI)
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=D637CF70-5783-4523-8D94-E5851D013567
• description - Essay describing examples of sustainable from nature communities such as forests, plains, mangrove swamps, sea grass, and coral reef communities. He discusses technologies associated with what he calls the "living machine", a contained ecosystem primarily powered by sunlight. His premise is that with good ecological design we can sustain a high civilization using only one tenth of the world's resources that industrial societies use today. This approach would dramatically reduce the negative human footprint by ninety percent. The essay begins: "Several months before his death, E. F. Schumacher, Nancy Jack Todd and I walked together through a temple in Bali. It was dusk. The bright red of the sunset was fading into darkness as we walked. In the temple grounds large trees cast a powerful presence. I could sense that Fritz was worried. He spoke of a recent meeting with U.S. President Carter and of his inability to communicate his sense of urgency about the environment. He felt the story of the Earth seemed beyond the political frame of most people. The question remains today: are we as a species going to stampede, lemming-like, over a cliff? Is it possible for us to chart a new course and reverse the current apocalyptic trend? Is there an alternative technological and cultural foundation for society that can bring humanity into harmony with the Earth and its support systems? "
418. Selecting a Sprinkler Irrigation System
• date - 2006-12
• creator - Tom Scherer, Extension Agricultural Engineer North Dakota State University, Agricultural Extension
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=D7CB8482-1DE5-4217-B6A0-E65E65B11E3E
• description - Online guide from the North Dakota State University, Agricultural Extension. "The four basic methods of irrigation are: subsurface irrigation ("subirrigation" which uses tile drain lines), surface or gravity irrigation, trickle irrigation (also called drip irrigation), and sprinkler irrigation. Of the acres currently irrigated in North Dakota, over 75 percent use some type of sprinkler system. Statewide, the center pivot is the most popular sprinkler system. If the sprinkler system is for a new installation, you have two important tasks you must perform before purchasing the system. First, you must check the county soil survey maps to make sure the soils in the field are irrigable. Second, you must have a readily available source of water near the field and have a State Water Commission-issued water permit for that water. The water source must be of sufficient quantity and quality for successful irrigation. Extension circular AE-92, Planning to Irrigate... A Checklist, provides more information on the requirements to begin irrigating. A sprinkler "throws" water through the air in an effort to simulate rainfall whereas the other three irrigation methods apply water directly to the soil, either on or below the surface. A sprinkler system can be composed of one or many sprinklers. In systems that use many sprinklers, the sprinklers are attached to a pipeline at a predetermined spacing in order to achieve a uniform application amount. When selecting a sprinkler system, the most important physical parameters to consider are: 1. The shape and size (acres) of the field. 2. The topography of the field. Are there many hills with steep slopes? 3. The amount of time and labor required to operate the system. How much time and labor do you have available? The center pivot system is very adaptable but doesn't work very well on irregularly shaped fields, long nar-row fields and fields that contain some type of obstruction (trees, farmsteads, etc.). In these situations, other sprinkler systems may be more effective."
419. Integer Iterations on a Circle
• date - 1998-01
• creator - Alexander Bogomolny
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=D90C13A3-2F4E-4C18-B8F1-DA22EE6D1E1E
• description - Integer Iterations on a Circle is a web-based software that presents the user with a problem, application to the problem, an experiment, and a solution to the problem. This is an example of the problem, "Place 4 integers on a circle. Proceed in iterations. At every step, compute all differences of pairs of consecutive numbers. Place the absolute values of these differences between the corresponding numbers and remove the numbers themselves. Show that after performing the step several times all the numbers will become 0." The software illustrates two different solutions to the problem using Honsberger and Coffman theories. - Parities - Distributive Law - Superposition Principle - Dot Patterns - Lucas's Theorem - Induction Argument - Linear Operator - Vector Space - Magic Squares - Stern-Brocot trees
420. Frog Island
• date - 1998-11
• creator - Parvati Dev
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=D9FEA41A-72EF-4A22-9CDE-3E832D009513
• description - Frog Island is an environment where students explore a 3D virtual outdoor habitat and visit various "huts" to learn about topics such as anatomy, physiology (digestion, respiration, circulation), and biomechanics. They have a workbook to outline the various lessons and allows them to enter observations, raise questions or enter answers to questions posed. There is a supplementary window where relevant text, images and videos can be displayed. To facilitate unstructured learning modes, students are encouraged to explore the virtual environment, interacting and noting any observations they may care to make. When a student has finished her lesson plans, she can produce a web document that summarizes her progress, the places she has visited and the annotations she has made along the way. This summary will be made available to her teachers, who are then free to post them to the web at the appropriate time. The virtual habitat resembles a natural setting with ponds, grass, trees and meadows. There are various theme-based activity huts and regions that provide students with the resources needed to complete their lesson plans and activities. The following huts have been identified for the initial Frog Island environment: Orientation Problem statement [for theme-based teaching] Diversity and Habitat -Genetic diversity -Adaptation -Concept map Organs Bones -Frog -Comparative -Microstructure Muscles -Types -Classification -Function -Lab experiments -Advanced Biomechanics -Levers -JavaFrog -Jumping frog contest Bioethics -Habitat preservation -Playing god -"good" science vs. "bad" science Keywords: Liberal Arts and Sciences
421. Engineered Structural Materials - Sustainable Building Design
• date - 2007-02
• creator - Bill Christensen, Webmaster and Founder Sustainable Sources, City of Austin, Texas
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=E3E4E35F-9D08-459E-B4E5-37DCCFE963D3
• description - "Engineered structural products are recycled/reconstituted wood materials that employ laminated wood chips or strands and fingerjointing (the gluing of larger pieces together). These materials fall into the general category of engineered wood. This means that the tolerances in stability, consistency, straightness, and strength are more precise than dimensional lumber, making the products easier to work with. In joist and rafter applications, the reconstituted products are particularly useful for long spans without bowing or lateral movement. These materials drastically minimize the amount of waste created in processing the raw materials. Waste wood and entire trees, regardless of species, shape, and age, can be used in making these products. Fingerjointed studs reduce waste in two ways. Short pieces that normally would be unusable are combined rather than disposed and the engineered quality of fingerjointed materials eliminate warping or cracking. The strength of the joints in good quality material is such that the solid wood portions will be more likely to break than the adhered fingerjoint." Online resource for green building design by the City of Austin, Texas offering practical information needed to implement green building practices to architects, builders, and homeowners in seeking to create sustainable buildings. The site is organized around the following topics: DEFINITIONS, CONSIDERATIONS, COMMERCIAL STATUS, IMPLEMENTATION ISSUES, GUIDELINES RESOURCES, PROFESSIONAL ASSISTANCE, COMPONENTS / MATERIALS / SYSTEMS, GENERAL ASSISTANCE, and INTERNET RESOURCES.
422. Introduction to Logic
• date - 2007-07
• creator - Nik Roberts
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=E78D29DC-EBDB-4D08-A58B-E68BE9D3DBC7
• description - This Web site provides, through a range of materials and tools, an introduction to the study of elementary logic covering propositional and predicate calculus. It is aimed especially at first year undergraduates studying Philosophy at the University of Oxford, but it is hoped that the site may be useful more widely, for anyone who would like to investigate the subject. The materials are structured as a series of eight detailed tutorials, which introduce the main concepts and definitions together with examples and exercises. The tutorials start with the notions of consistency and validity, and proceed to introduce a language and system of proof for propositional logic and for predicate logic. They include a tutorial on designators and a tutorial on relations. The language and system of proof (by means of tableaux, i.e. trees) are those to be found in W. Hodges, Logic, 2nd edition (Penguin, 2001). Within each tutorial topics have been arranged sequentially, care being taken to provide a reasonable amount of information per page so that study can be undertaken step by step. The site is also designed to aid quick navigation so that relevant materials can be quickly reached from various locations. For instance, there is always available in the lefthand frame a link to an A-Z index, which lists most of the terms covered in the tutorials, and links each to relevant sections of the text. A special feature of this site is Tableau3, a program to enable students to practise doing tableau (i.e. tree) proofs for propositional and predicate logic. Tableau3 is similar in functionality to a much earlier program, Tableau2, but is written in Java (rather than DOS), and so can run on most computer setups, either over the Web or on a local machine. The material is compatible with: W. Hodges, Logic, 2nd edition (Penguin, 2001).
423. Introduction to the Collections Framework
• date - 2006-11
• creator - Zukowski John
• provider - NSDL OAI Repository
• location - http://www.needs.org/needs/?path=/public/search/search_results/learning_resource/summary/index.jhtml&id=EC543766-17B1-42E6-876B-A83AC9ECFB3F
• description - In working through this Short Course and the accompanying magercises you will learn to use the Collections Framework to store and manipulate groups of data as a single unit, a collection. Topics include a discussion and demonstration of many of the abstract data types familiar from computer science data structure curriculum: maps, sets, lists, trees, arrays, hashtables, and other collections. In addition, the courseware includes coverage of the data structures and algorithms associated with these abstractions.
424. Statistical Learning Theory: Graphical Models
• date - 2006-11
• creator - Martin Wainwright
• provider - NSDL OAI Repository
• location - http://www.engineeringpathway.com/view.jhtml?id=F1AF766B-B76E-4D7E-917C-6A273CB778A8
• description - This course is a 3-unit course that provides an introduction to the area of probabilistic models based on graphs. These graphical models provide a very flexible and powerful framework for capturing statistical dependencies in complex, multivariate data. Key issues to be addressed include representation, efficient algorithms, inference and statistical estimation. These concepts will be illustrated using examples drawn from various application domains, including machine learning, signal processing, communication theory, computational biology, computer vision etc. Outline: #Basics on graphical models, Markov properties, recursive decomposability, elimination algorithms # Sum-product algorithm, factor graphs, semi-rings # Markov properties of graphical models # Junction tree algorithm # Chains, trees, factorial models, coupled models, layered models # Kalman filtering and Rauch-Tung-Striebel smoothing # Hidden Markov models (HMM) and forward-backward # Exponential family, sufficiency, conjugacy # Frequentist and Bayesian methods # The EM algorithm # Conditional mixture models, hierarchical mixture models # Factor analysis, principal component analysis (PCA), canonical correlation analysis (CCA), independent component analysis (ICA) # Importance sampling, Gibbs sampling, Metropolis-Hastings # Variational algorithms: mean field, belief propagation, convex relaxations # Dynamical graphical models # Model selection, marginal likelihood, AIC, BIC and MDL # Applications to signal processing, bioinformatics, communication, computer vision etc. The website has links to lecture notes, webcasts of lectures, readings, and projects.
425. Mathematical Methods in Artificial Intelligence
• date -
• creator - Edward A. Bender
• provider - NSDL OAI Repository
• location - http://www.wiley.com/WileyCDA/WileyTitle/productCd-0818672005.html
• description - Mathematical Methods in Artificial Intelligence introduces the student to the important mathematical foundations and tools in AI and describes their applications to the design of AI algorithms. This useful text presents an introductory AI c ourse b ased on the most important mathematics and its applications. It focuses on important topics that are proven useful in AI and involve the most broadly applicable mathematics. *The book explores AI from three different viewpoints: goals, methods or tools, and achievements and failures. Its goals of reasoning, planning, learning, or language understanding and use are centered around the expert system idea. The tools of A I are presented in terms of what can be incorporated in the data structures. The book looks into the concepts and tools of limited structure, mathematical logic, logic-like representation, numerical information, and nonsymbolic structures. *The text emphasizes the main mathematical tools for representing and manipulating knowledge symbolically. These are various forms of logic for qualitative knowledge, and probability and related concepts for quantitative knowledge. The main tools for manipulating knowledge nonsymbolically, as neural nets, are optimization methods and statistics. This material is covered in the text by topics such as trees and search, classical mathematical logic, and uncertainty and reasoning. A solutions diskette is available, please call for more information.
426. A primer of forestry
• date -
• creator - Pinchot, Gifford, 1865-1946
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - pt. 1. The forest -- pt. 2. Practical forestry
427. Clouds - Time Lapse (Wide Screen 16:9)
• date - 2007-00-00T00:00:00Z
• creator - C. E. Price
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
428. Yoshi's Island (SNES/GBA) - Individual Level 100%s (Total: 2:13:24)
• date - 2006-00-00T00:00:00Z
• creator -
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Individual level 100% runs on Super Mario World 2: Yoshi's Island. Timing is from end of opening level wipe, to going through goal ring or the start of circular boss explosion. (start-end of character control). Recent runs come in three or four different qualities. <pre>Level #/name Time Date Player<br>1-1 Make Eggs, Throw Eggs 0:51 28.09.06 Mychal 'trihex' Jefferson<br>1-2 Watch Out Below! 0:56 03.04.06 Mychal 'trihex' Jefferson<br>1-3 The Cave Of Chomp Rock 1:12 12.07.06 Mychal 'trihex' Jefferson<br>1-4 Burt The Bashful's Fort 2:17 05.04.06 Mychal 'trihex' Jefferson<br>1-5 Hop! Hop! Donut Lifts 2:28 25.06.06 Mychal 'trihex' Jefferson<br>1-6 Shy-Guys On Stilts 1:53 23.10.06 Mychal 'trihex' Jefferson<br>1-7 Touch Fuzzy Get Dizzy 1:17 31.05.06 Mychal 'trihex' Jefferson<br>1-8 Salvo The Slime's Castle 2:24 23.10.06 Mychal 'trihex' Jefferson<br>1-E Poochy Ain't Stupid 1:03 08.04.06 Mychal 'trihex' Jefferson<br>2-1 Visit Koopa And Para-Koopa 2:24 01.06.06 Mychal 'trihex' Jefferson<br>2-2 The Baseball Boys 2:55 29.05.06 Mychal 'trihex' Jefferson<br>2-3 What's Gusty Taste Like? 1:39 08.10.06 Mychal 'trihex' Jefferson<br>2-4 Bigger Boo's Fort 2:58 13.04.06 Mychal 'trihex' Jefferson<br>2-5 Watch Out For Lakitu 1:54 05.06.06 Mychal 'trihex' Jefferson<br>2-6 The Cave Of The Mystery Maze 1:58 15.04.06 Mychal 'trihex' Jefferson<br>2-7 Lakitu's Wall 2:32 04.06.06 Mychal 'trihex' Jefferson<br>2-8 The Potted Ghost's Castle 4:25 17.04.06 Mychal 'trihex' Jefferson<br>2-E Hit That Switch!! 0:49 01.06.06 Mychal 'trihex' Jefferson<br>3-1 Welcome To Monkey World! 1:18 17.04.06 Mychal 'trihex' Jefferson<br>3-2 Jungle Rhythm... 1:09 07.06.06 Mychal 'trihex' Jefferson<br>3-3 Nep-Enuts' Domain 3:04 06.06.06 Mychal 'trihex' Jefferson<br>3-4 Prince Froggy's Fort 3:57 22.06.06 Mychal 'trihex' Jefferson<br>3-5 Jammin' Through The Trees 1:16 19.04.06 Mychal 'trihex' Jefferson<br>3-6 The Cave Of Harry Hedgehog 1:46 20.04.06 Mychal 'trihex' Jefferson<br>3-7 Monkeys' Favorite Lake 2:25 01.05.06 Mychal 'trihex' Jefferson<br>3-8 Naval Piranha's Castle 3:21 06.05.06 Mychal 'trihex' Jefferson<br>3-E More Monkey Madness 0:44 07.05.06 Mychal 'trihex' Jefferson<br>4-1 GO! GO! MARIO!! 1:51 16.10.06 Mychal 'trihex' Jefferson<br>4-2 The Cave Of The Lakitus 1:44 08.10.06 Mychal 'trihex' Jefferson<br>4-3 Don't Look Back! 1:51 08.10.06 Mychal 'trihex' Jefferson<br>4-4 Marching Milde's Fort 4:49 11.05.06 Mychal 'trihex' Jefferson<br>4-5 Chomp Rock Zone 1:35 10.05.06 Mychal 'trihex' Jefferson<br>4-6 Lak
429. [arh023] makunouchi bento - avebell
• date - 2007-09-28T00:00:00Z
• creator -
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Avebell Dark copper bells, giant stone trees. Sad birds looking in the lake to peck their distorted images. Hairy grey grass growing fast on the inside. And every senior ghost has its own bell. There is not night or day - just fog from swamps. There are no clouds, just slimy paper made zeppelins. Thoughts and dreams are slashing each other to death. Romans and greeks are the only citizens left. And two venetian old fools. They all look translucent like projected by a huge Merkur portable projector (35mm - 1922). Soldiers with led boots marching indefinitely, Do not reach the battlefield ! There is Avebell. by Makunouchi Bento <a href="http://makunouchibento.inpuj.net">http://makunouchibento.inpuj.net</a> <a href="http://myspace.com/makunouchibento">http://makunouchibento.inpuj.net</a> Makunouchi Bento are: Felix Petrescu (waka x) Valentin Toma (qewza) (c) makunouchi bento, 2007
430. A primer of forestry
• date -
• creator - Pinchot, Gifford, 1865-1946
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - pt. 1. The forest -- pt. 2. Practical forestry
431. Some abnormal water relations in citrus trees of the arid Southwest and their possible significance
• date -
• creator - Hodgson, Robert W. (Robert Willard), 1893-
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description - Bibliographical foot-notes
432. The story of the forest
• date -
• creator - Dorrance, John Gordon, 1890-
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
433. What may be learned from a tree
• date - 1859-00-00T00:00:00Z
• creator - Coultas, Harland, d. 1877
• provider - Internet Archive OAI Repository
• location - http://www.archive.org
• description -
434. Discrete Structures
435. Discrete Structures
436. Data Structures
437. Development of nursery for producing diseased free citrus propagation materials
• date - 2005
• creator - Sdoodee, R.
• provider - NSDL OAI Repository
• location - http://www.sjst.psu.ac.th/journal/27-4-pdf/07-citrus-propagation-material.pdf
• description - A prototype of nursery house (5×8×3.80 m) was established for producing disease free citrus propagation materials. The frame of prototype nursery house was made of galvanized pipe and it was covered with UV-resistance nylon net (32 mesh). Optimum temperature and relative humidity in the prototype nursery house were automatically controlled. It was compared with a commercial nethouse (6×9×4.40 m) and a shade house (4×6×2.50 m). The capacity of the prototype nursery house, commercial nethouse and shade house was assessed by growth determination of plants grown inside for 3 months. The plant materials used for testing were Troyer seedlings, Shogun mandarin mother plants and Neck orange nursery trees. It was found that the plants grown in the prototype nursery house and commercial nethouse exhibited significantly higher growth than those plants in the shade house. Differences of temperature and relative humidity in the prototype nursery house, commercial nethouse and shade house were evaluated. It was prominent that the temperature and relative humidity during the experimental period in the commercial nethouse were highest, while they were lowest in the shade house. An occurrence of canker diseases markedly increased in the commercial nethouse because of high humidity and temperature. Leaf destruction by main insect pests wasa serious problem in the shade house. From the results, it is suggested that the prototype nursery house is suitable for producing disease free citrus propagation materials in southern Thailand.

Author: Eric Lease Morgan <emorgan@nd.edu>
Date created: 2004-08-25
Date updated: 2007-01-01