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Articles 16021 - 16050 of 19705

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Assessment And Restoration Of A Neighborhood Wetland Invaded By Exotic Plant Species, Ryan Neal, Kimberly R. Payne, Lorena Moreno, Graham Duffy, Jonathan Peck, Mary C. Savin Jan 2004

Assessment And Restoration Of A Neighborhood Wetland Invaded By Exotic Plant Species, Ryan Neal, Kimberly R. Payne, Lorena Moreno, Graham Duffy, Jonathan Peck, Mary C. Savin

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

The University of Arkansas Crop, Soil, and Environmental Sciences (CSES) Club adopted a local wetland in the spring of 2002 through the Fayetteville Parks and Recreation Department. This project has allowed students to interact with local community and governmental organizations as well as other academic departments within the university. Students have gained valuable laboratory and field experience through characterizing hydric soils, identifying bird and plant species, and analyzing water quality, soil nutrients, and microbial biomass. Under the main goal of restoring the wetland, the club has outlined both short and long-term objectives including soil and water assessments; removal of two …


The Effects Of Environmentally Relevant Doses Of Perchlorate (Clo4-) On Rana Pipiens Metamorphosis And Development, Andrea N. Golli Jan 2004

The Effects Of Environmentally Relevant Doses Of Perchlorate (Clo4-) On Rana Pipiens Metamorphosis And Development, Andrea N. Golli

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to assess the effects of environmentally relevant concentrations of perchlorate on the development and growth of Rana pipiens. Ammonium perchlorate is a rocket fuel oxidizer that is known to interfere with the function of the thyroid gland and some of the highest United States surface water concentration exists in the Las Vegas Wash, NV. Perchlorate not only blocks the body’s ability to incorporate iodine into T3 and T4 hormones through the sodium iodine symporter system, but also depletes the thyroid glands’ internal stores of iodine. Many of the steps that regulate metamorphosis in amphibians …


The Role Of Farm Dams As Refugia For Aquatic Invertebrates In A Salinised Landscape, South Western Australia, Jean-Michel Benier Jan 2004

The Role Of Farm Dams As Refugia For Aquatic Invertebrates In A Salinised Landscape, South Western Australia, Jean-Michel Benier

Theses: Doctorates and Masters

In a salinised landscape farm dams may represent the last truly freshwater surface resource, and therefore provide refuge habitats for the biota of wetlands affected by increasing salinity. One wetland threatened by increased salinity in south-west Western Australia is Lake Toolibin. It is listed as a Wetland of International Importance under the Ramsar Convention in recognition of its high conservation value, and remediation actions to halt (and possibly reverse) further increases in salinity are being undertaken at this wetland. Farm dams act as aquatic refugia if they convey resistance and/or resilience to the biotic communities of a disturbed habitat. This …


In Vitro Propagation Of Some Western Australian Seagrasses, Julia Wilson Jan 2004

In Vitro Propagation Of Some Western Australian Seagrasses, Julia Wilson

Theses: Doctorates and Masters

The development of a successful protocol for micropropagating seagrass provides a valuable tool for seagrass-restoration programs and a facility to study their biology (especially their physiology). This work reports on some of the culture requirements of some seagrasses that are commonly found in Western Australia: Posidonia coriacea, P. sinuosa, P. australis and Halophila ovalis. The protocol developed for H. ovalis allows very rapid multiplication and sustainable growth of cultures while the protocol developed for Posidonia requires further development. The culture of Posidonia cariacea proved to be problematic however experimental media that provided insights into its culture conditions. The carbohydrate source …


What Happens To Biblical Truth If The Sda Church Accepts Theistic Evolution?, Norman R. Gulley Jan 2004

What Happens To Biblical Truth If The Sda Church Accepts Theistic Evolution?, Norman R. Gulley

Journal of the Adventist Theological Society

No abstract provided.


Issues In "Intermediate" Models Of Origins, Jim Gibson Jan 2004

Issues In "Intermediate" Models Of Origins, Jim Gibson

Journal of the Adventist Theological Society

No abstract provided.


Beach-Cast Wrack As A Determinant Of Macroinvertebrate Assemblages And Trophic Subsidy To Sandy Beach Ecosystems, Rebecca Ince Jan 2004

Beach-Cast Wrack As A Determinant Of Macroinvertebrate Assemblages And Trophic Subsidy To Sandy Beach Ecosystems, Rebecca Ince

Theses : Honours

The transport of detached macrophytes from seagrass meadows and reefs, otherwise known as wrack, has been identified in some parts of the world as a marine subsidy which can increase the productivity of coastal ecosystems. The aim of this study was to determine whether wrack deposits act as a marine subsidy on sandy beaches in Perth, by determining whether it influences the structure of, and is a source of nutrient to, the macroinvertebrate communities in this ecosystem. This was achieved by examining the abundance, composition and nutrient source of macrofauna, including epifauna, infauna and flying fauna, on three sandy beaches …


Demographic Estimates From Y Chromosome Microsatellite Polymorphisms: Analysis Of A Worldwide Sample, J. Michael Macpherson, Sohini Ramachandran, Lisa Diamond, Marcus W. Feldman Jan 2004

Demographic Estimates From Y Chromosome Microsatellite Polymorphisms: Analysis Of A Worldwide Sample, J. Michael Macpherson, Sohini Ramachandran, Lisa Diamond, Marcus W. Feldman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Polymorphisms in microsatellites on the human Y chromosome have been used to estimate important demographic parameters of human history. We compare two coalescent-based statistical methods that give estimates for a number of demographic parameters using the seven Y chromosome polymorphisms in the HGDP-CEPH Cell Line Panel, a collection of samples from 52 worldwide populations. The estimates for the time to the most recent common ancestor vary according to the method used and the assumptions about the prior distributions of model parameters, but are generally consistent with other global Y chromosome studies. We explore the sensitivity of these results to assumptions …


The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens Jan 2004

The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens

Jeffrey Stevens Publications

Animals may share food to gain immediate or delayed fitness benefits. Previous studies of sharing have concentrated on delayed benefits such as reciprocity, trade and punishment. This study tests an alternative model (the harassment or sharing–under–pressure hypothesis) in which a food owner immediately benefits because sharing avoids costly harassment from a beggar. I present an experiment that varies the potential ability of the beggar to harass, and of the owner to defend the food, to examine the effects of harassment on food sharing in two primate species: chimpanzees (Pan troglodytes) and squirrel monkeys (Saimiri boliviensis). For …


A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby Jan 2004

A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby

Jeffrey Stevens Publications

Many animal species, from arthropods to apes, share food. This paper presents a new framework that categorizes nonkin food sharing according to two axes: (1) the interval between sharing and receiving the benefits of sharing, and (2) the currency units in which benefits accrue to the sharer (especially food versus nonfood). Sharers can obtain immediate benefits from increased foraging efficiency, predation avoidance, mate provisioning, or manipulative mutualism. Reciprocity, trade, status enhancement and group augmentation can delay benefits. When benefits are delayed or when food is exchanged for nonfood benefits, maintaining sharing can become more difficult because animals face discounting and …


Clark’S Nutcrackers (Nucifraga Columbiana) And The Effects Of Goal-Landmark Distance On Overshadowing, Aleida J. Goodyear, Alan Kamil Jan 2004

Clark’S Nutcrackers (Nucifraga Columbiana) And The Effects Of Goal-Landmark Distance On Overshadowing, Aleida J. Goodyear, Alan Kamil

Papers in Behavior in Biological Sciences

Three groups of Clark’s nutcrackers (Nucifraga columbiana) were trained to find a goal location defined by an array of 4 landmarks that varied in goal–landmark distance. The arrays for each group differed in the distance of the closest landmark and contained goal–landmark distances that were common across groups, allowing for the examination of the effects of both relative and absolute goal–landmark distance on encoding of a landmark array. All 3 groups readily learned the task and were subsequently tested in probe tests with only single landmarks from the array available. Search error in tests with single landmarks was …


Social Play In Kaka (Nestor Meridionalis) With Comparisons To Kea (Nestor Notabilis), Judy Diamond, Alan B. Bond Jan 2004

Social Play In Kaka (Nestor Meridionalis) With Comparisons To Kea (Nestor Notabilis), Judy Diamond, Alan B. Bond

Papers in Behavior in Biological Sciences

Social play in the kaka (Nestor meridionalis), a New Zealand parrot, is described and contrasted with that of its closest relative, the kea (Nestor notabilis), in one of the first comparative studies of social play in closely related birds. Most play action patterns were clearly homologous in these two species, though some contrasts in the form of specific play behaviors, such as kicking or biting, could be attributed to morphological differences. Social play in kakas is briefer, more predictable, and less sequentially diverse than that shown by keas. Kaka play also appears to be restricted to …


Sociality And The Evolution Of Intelligence, Alan Kamil Jan 2004

Sociality And The Evolution Of Intelligence, Alan Kamil

Papers in Behavior in Biological Sciences

Two recently published studies provide important new data relevant to the evolution of human intelligence. Both studies of social behavior in baboons, Bergman et al. demonstrated that baboons use two criteria simultaneously to classify other troop members, and Silk et al. showed that highly social female baboons have higher reproductive success than less social females. Taken together, these studies provide strong evidence for the importance of social context in cognitive evolution.


The Double-Edged Sword Of Biological Control In Conservation And Restoration, Svata M. Louda, Peter Stiling Jan 2004

The Double-Edged Sword Of Biological Control In Conservation And Restoration, Svata M. Louda, Peter Stiling

Svata M. Louda Publications

The most fundamental question in considering deliberate introductions of exotic species against invasive species is whether the outcomes can be predicted precisely enough a priori to know with some certainty that the benefits will outweigh the environmental costs. This issue is obscured by reiteration of an overly simplistic description of the ecology underlying biological control. Classical biological control is not a simple exercise in “community re-assemblage” (Hoddle 2004); it involves the introduction of alien organisms into new species assemblages, in new physical environments, and without the rest of their foodweb. Predicting the outcome of such introductions is infinitely more complex …


Phenological Synchrony Affects Interaction Strength Of An Exotic Weevil With Platte Thistle, A Native Host Plant, F. Leland Russell, Svata M. Louda Jan 2004

Phenological Synchrony Affects Interaction Strength Of An Exotic Weevil With Platte Thistle, A Native Host Plant, F. Leland Russell, Svata M. Louda

Svata M. Louda Publications

Phenological synchrony of a consumer population with its resource populations is expected to affect interaction intensity. We quantified phenological variation and synchrony of populations of an invasive Eurasian flower head weevil, Rhinocyllus conicus, that consumes florets, ovules, and seeds of developing flower heads of a native North American thistle, Cirsium canescens, in Sand Hills prairie in Nebraska, USA. Variation in timing of adult activity among weevil populations was larger than variation in timing of flower head development among C. canescens populations, and it drove the observed variation in the phenological synchrony between weevil and host plant populations. Furthermore, …


Local- Vs. Landscape-Scale Indirect Effects Of An Invasive Weed On Native Plants, Tatyana A. Rand, F. Leland Russell, Svata M. Louda Jan 2004

Local- Vs. Landscape-Scale Indirect Effects Of An Invasive Weed On Native Plants, Tatyana A. Rand, F. Leland Russell, Svata M. Louda

Svata M. Louda Publications

Insect-mediated indirect interactions between native plant species recently have been shown to be important determinants of plant performance in a number of ecological communities. However, the potential indirect effects of exotic plant invasion on native plant species are not well understood. We examined whether the presence or proximity of the targeted exotic weed, musk thistle, influences the magnitude of attack on native thistles by the introduced biological control, flowerhead weevil. At the local scale, we quantified weevil egg densities on heads of the native wavyleaf thistle growing at different distances (0 to 100 m) from patches of the exotic thistle. …


Weeds [From Encyclopedia Of The Great Plains], Svata M. Louda Jan 2004

Weeds [From Encyclopedia Of The Great Plains], Svata M. Louda

Svata M. Louda Publications

According to the U.S. Department of Agriculture, countless hours and millions of dollars are spent each year to control weeds, and millions more--hours and dollars--are lost in yield reductions. However, what exactly is a weed? And what makes a plant a weed? Many people are surprised to learn that a weed is technically "a plant out of place." So one person's weed can be someone else's salad green, pharmaceutical, transgenic crop, or wildflower! What are the characteristics of plants that often grow out of place? One characteristic is a tendency to reach high numbers rapidly and to replace or slow …


The Geometry Of Foraging Patterns: Components Of Thoroughness In Random Searching, Alan B. Bond Jan 2004

The Geometry Of Foraging Patterns: Components Of Thoroughness In Random Searching, Alan B. Bond

Papers in Behavior in Biological Sciences

A Monte Carlo simulation of the movements of a randomly-searching predator was used to develop a novel geometrical measure, the "thoroughness" of the search, and to investigate the effects of meander, turn asymmetry, and path length. Thoroughness varied directly with the meander and the square of the asymmetry measure and remained relatively invariant with path length. The regularity of its relationship to the generating parameters of the search and the ease with which it may be estimated from field data recommend thoroughness for use in characterizing empirical search patterns and in testing for the occurrence of systematic searching.


Friends Of Red Rock Canyon Quarterly Meeting, Public Lands Institute Jan 2004

Friends Of Red Rock Canyon Quarterly Meeting, Public Lands Institute

Presentations (PLI)

The Public Lands Institute is dedicated to strengthening the national fabric that is essential for the protection, conservation, and management of public lands.


Oliver Ranch Science School Complex & Wild Horse And Burro Facility: Quarterly Progress Report, Period Ending June 30, 2004, Margaret N. Rees Jan 2004

Oliver Ranch Science School Complex & Wild Horse And Burro Facility: Quarterly Progress Report, Period Ending June 30, 2004, Margaret N. Rees

Oliver Ranch Project

Assist in project coordination between numerous stakeholders such as the Clark County School System, Desert Research Institute, Community College of Southern Nevada, UNR Cooperative Extension, Nevada State College, local museums, state parks, non-profit organizations, federal agencies, and the public to ensure appropriate educational curricular activities and venues are provided for in the conceptual design of the School and the Wild Horse and Burro facility where appropriate as well as assist in the NEPA process as needed. The activities will be conducted at least in part by university faculty, staff and students as part of the university’s research, teaching, and service …


Oliver Ranch Science School Complex & Wild Horse And Burro Facility: Quarterly Progress Report, Period Ending December 31, 2004, Margaret N. Rees Jan 2004

Oliver Ranch Science School Complex & Wild Horse And Burro Facility: Quarterly Progress Report, Period Ending December 31, 2004, Margaret N. Rees

Oliver Ranch Project

Assist in project coordination between numerous stakeholders such as the Clark County School System, Desert Research Institute, Community College of Southern Nevada, UNR Cooperative Extension, Nevada State College, local museums, state parks, non-profit organizations, federal agencies, and the public to ensure appropriate educational curricular activities and venues are provided for in the conceptual design of the School and the Wild Horse and Burro facility where appropriate as well as assist in the NEPA process as needed. The activities will be conducted at least in part by university faculty, staff and students as part of the university’s research, teaching, and service …


Ecological Species Groups Of South Carolina's Jocassee Gorges, Southern Appalachian Mountains, Scott R. Abella, Victor B. Shelburne Jan 2004

Ecological Species Groups Of South Carolina's Jocassee Gorges, Southern Appalachian Mountains, Scott R. Abella, Victor B. Shelburne

Public Policy and Leadership Faculty Research

Ecological species groups, consisting of assemblages of co-occurring plant species exhibiting similar environmental affinities, were developed for ground-flora and tree strata in late- successional forests on a 13,000 ha southern Appalachian landscape. We distinguished 11 ground-flora groups that included 50 species and six tree groups comprised of 19 species. Ground-flora groups ranged from a xeric Vaccinium group (including Vaccinium pallidum, Euphorbia corollata, and Piptochaetium avenaceum) to a mesic Rhododendron group (typified by Rhododendron maximum, Mitchella repens, and Hexastylis heterophylla). Tree groups ranged from a Quercus coccinea group to a Tsuga canadensis group. Consistent with previous research, species groups exhibited a …


Distribución Geográfica De La Fauna De Anfibios Del Uruguay, Diego Nuñez, Raúl Maneyro, José A. Langone, Rafael O. De Sá Jan 2004

Distribución Geográfica De La Fauna De Anfibios Del Uruguay, Diego Nuñez, Raúl Maneyro, José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Datos precises sobre la distribución geográfica de los organismos de una región son necesarios y prerrequisito para entender las interrelaciones ecológicas entre las comunidades biológicas. Esta información también contribuye a entender el componente histórico de la región posibilitando la determinación de centros de origen y el establecimiento de patrones de diversidad (Ron, 2000), así mismo posibilita realizar inferencias acerca de los mecanismos de especiación en los diferentes grupos zoológicos (Bridarolli & Di Tada, 1994).

La distribución geográfica de los anfibios en Uruguay ha sido parcialmente reportada (Achaval & Olmos, 1997; Langone, 1995; Maneyro et al, 1995; Maneyro & Langone, 2001). …


Características Histológicas De La Tumefacción Frontal De Melanophryniscus (Amphibia: Anura: Bufonidae), Daniel E. Naya, José A. Langone, Rafael O. De Sá Jan 2004

Características Histológicas De La Tumefacción Frontal De Melanophryniscus (Amphibia: Anura: Bufonidae), Daniel E. Naya, José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Se analizó la histología tegumentaria de la región cefálica en seis especies del género Melanophryniscus, pertenecientes a los grupos stelzneri (4) y tumifrons (2), con el objetivo de esclarecer la estructura de la tumefacción frontal y su posible función. Las características generales de la histología del grupo stelzneri, coincidieron con las descripciones tegumentarias existentes para el género. Sin embargo, la región cefálica frontal en las dos especies del grupo tumifrons muestran cambios histológicos correlacionados a la tumefacción frontal. Esta estructura presenta una organización similar a otras macroglándulas presentes en la dermis de anuros (e.g., parotoides, paracnémicas), y por tanto se …


On The Engimatic Distribution Of The Honduran Endemic Leptodactylus Silvanimbus (Amphibia: Anura: Leptodactylidae), W. R. Heyer, Rafael O. De Sá, Sarah Muller Jan 2004

On The Engimatic Distribution Of The Honduran Endemic Leptodactylus Silvanimbus (Amphibia: Anura: Leptodactylidae), W. R. Heyer, Rafael O. De Sá, Sarah Muller

Biology Faculty Publications

Most species of the frog genus Leptodactylus occur in South America, and all authors who have treated the zoogeography of the genus have concluded that it originated somewhere in South America (e.g., Savage 1982). Savage (1982, 518) summarized the historical herpetofaunal units of the Neotropics as follows: "All evidence points to an ancient contiguity and essential similarity of a generalized tropical herpetofauna that ranged over tropical North, Middle, and most of South America in Cretaceous-Paleocene times. Descendents of this fauna are represented today by the South and Middle American tracks (Elements). To the north of this fauna ranged a subtropical-temperate …


Stage-Specific And Interactive Effects Of Sedimentation And Trout On A Headwater Stream Salamander, Winsor H. Lowe, Keith H. Nislow, Douglas T. Bolger Jan 2004

Stage-Specific And Interactive Effects Of Sedimentation And Trout On A Headwater Stream Salamander, Winsor H. Lowe, Keith H. Nislow, Douglas T. Bolger

Dartmouth Scholarship

In species with complex life cycles, stage-specific effects of environmental conditions combine with factors regulating stage-specific recruitment to determine population-level response to habitat disturbance. The abundance of the stream salamander Gyrinophilus porphyriticus(Plethodontidae) is negatively related to both logging-associated sedimentation and brook trout (Salvelinus fontinalis) in headwater streams throughout New Hampshire, USA. To understand the mechanisms underlying these patterns, we investigated stage-specific and interactive effects of sedimentation and brook trout on G. porphyriticus. We conducted quantitative surveys of salamanders, brook trout, and substrate embeddedness in 15 first-order streams and used a controlled experiment to test the direct and interactive effects of …


On The Cranial Anatomy Of The Polycotylid Plesiosaurs, Including New Material Of Polycotylus Latipinnis, Cope, From Alabama, F. Robin O’Keefe Jan 2004

On The Cranial Anatomy Of The Polycotylid Plesiosaurs, Including New Material Of Polycotylus Latipinnis, Cope, From Alabama, F. Robin O’Keefe

Biological Sciences Faculty Research

The cranial anatomy of plesiosaurs in the family Polycotylidae (Reptilia: Sauropterygia) has received renewed attention recently because various skull characters are thought to indicate plesiosauroid, rather than pliosauroid, affinities for this family. New data on the cranial anatomy of polycotylid plesiosaurs is presented, and is shown to compare closely to the structure of cryptocleidoid plesiosaurs. The morphology of known polycotylid taxa is reported and discussed, and a preliminary phylogenetic analysis is used to establish ingroup relationships of the Cryptocleidoidea. This study also presents new material referable to Polycotylus latipinnis from the Mooreville Chalk Formation of Alabama. This skeleton is largely …


Adventist Theology And Deep Time/Evolutionary Theory: Are They Compatible?, Fernando Canale Jan 2004

Adventist Theology And Deep Time/Evolutionary Theory: Are They Compatible?, Fernando Canale

Journal of the Adventist Theological Society

No abstract provided.


Fascism, Peter Staudenmaier Jan 2004

Fascism, Peter Staudenmaier

History Faculty Research and Publications

No abstract provided.


Metabolic Rate Models And The Substitutability Of Predator Populations, David R. Chalcraft, William J. Resetarits Jr. Jan 2004

Metabolic Rate Models And The Substitutability Of Predator Populations, David R. Chalcraft, William J. Resetarits Jr.

Biological Sciences Faculty Publications

1. Much of the debate surrounding the consequences of biodiversity loss centres around the issue of whether different species are functionally similar in their effects on ecological processes. In this study, we examined whether populations consisting of smaller, more abundant individuals are functionally similar to populations of the same species with larger, fewer individuals.
2. We manipulated the biomass and density of banded sunfish (Enneacanthus obesus) and measured their impact on populations of Southern leopard frog (Rana sphenocephala) larvae. We also evaluated the ability of models relating metabolic rate to body size to predict the relative …