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Articles 1621 - 1650 of 1769

Full-Text Articles in Life Sciences

Microbial Endemism And Biogeography, Brian P. Hedlund, James T. Staley Jan 2004

Microbial Endemism And Biogeography, Brian P. Hedlund, James T. Staley

Life Sciences Faculty Research

The topic of microbial biogeography is almost 100 years old, however, when confronted with questions about the existence and extent of endemism in the microbial world, many microbiologists respond with opinions and theoretical arguments rather than examples of well-conducted studies. We begin this chapter with an overview of this debate as it applies to free-living prokayotes in part because there are relatively few good microbial biogeography studies. Furthermore, the arguments help to frame microbial biogeography in the larger context of biodiversity in that if endemism is common, then many more species exist.

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Public Posting As A Strategy To Increase Walking: A Worksite Intervention, Rayleen Earney, Timothy J. Bungum Jan 2004

Public Posting As A Strategy To Increase Walking: A Worksite Intervention, Rayleen Earney, Timothy J. Bungum

Environmental & Global Health Faculty Research

Because most American adults do not meet recommended physical activity guidelines, the need for new and innovative strategies is apparent. The current study employed public posting in an attempt to increase walking behavior in a worksite setting. Pedometer generated data was publicly posted in a prominent location in the worksite. In our study that utilized a pre-experimental design, we found that walking steps were statistically higher during the intervention and in a post intervention period as compared to the baseline data. We conclude that the public posting of physical activity data has the potential to increase walking behavior.

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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.

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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 …

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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 …

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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 …

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Ecology Of Eastern Prickly Pear Cactus (Opuntia Humifusa) In Oak Openings Preserve, Northwestern Ohio, Scott R. Abella, John F. Jaeger Jan 2004

Ecology Of Eastern Prickly Pear Cactus (Opuntia Humifusa) In Oak Openings Preserve, Northwestern Ohio, Scott R. Abella, John F. Jaeger

Public Policy and Leadership Faculty Research

Opuntia humifusa (eastern prickly pear cactus) is listed as potentially threatened in Ohio, and we examined the characteristics of O. humifusa sites in Oak Openings Preserve in northwestern Ohio’s Oak Openings region in an attempt to provide data that may help protect this species. Opuntia humifusa occurrences were associated with loose sands of the xeric Udipsamment Ottokee and Oakville soil series on sites that had been cleared before the 1940s during failed agricultural attempts. Shading by encroaching canopy trees is a threat to several O. humifusa populations in Oak Openings Preserve, and treatments that reduce canopy cover at these sites …

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Tree Thinning And Prescribed Burning Effects On Ground Flora In Arizona Ponderosa Pine Forests: A Review, Scott R. Abella Jan 2004

Tree Thinning And Prescribed Burning Effects On Ground Flora In Arizona Ponderosa Pine Forests: A Review, Scott R. Abella

Public Policy and Leadership Faculty Research

Ground flora is an important response variable to monitor after tree thinning and prescribed burning treatments designed to restore Arizona ponderosa pine (Pinus ponderosa P.& C. Lawson) forests. This paper reviews published literature on the effects of thinning and burning on ground flora in Arizona ponderosa pine forests in five main categories of research: ground flora biomass, species diversity, plant community composition, population processes, and individual species ecology. Research published to date suggests that thinning and burning generally increase ground flora biomass, whereas other categories of research such as community composition and population processes have been little studied in Arizona …

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Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer Jan 2004

Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer

Public Policy and Leadership Faculty Research

Midwest oak savanna communities are noted for their unusual plant assemblages, but these communities have been reduced by more than 98% because of changing land uses and conversion to closed-canopy forests. We initiated an ongoing 15-year experiment in 1988 to restore a 40-ha black oak (Quercus velutina) savanna by applying burn treatments that historically maintained this vegetation type. Groundlayer composition changed significantly for both the burn treatment and the control, with the burn treatment exhibiting slight increases in herbs such as wild lupine (Lupinus perennis) and hairy puccoon (Lithospermum caroliniense), both of which are species requiring greater insolation. Burn treatments …

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

Oliver Ranch Science School Complex & Wild Horse And Burro Facility: Quarterly Progress Report, Period Ending September 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 …

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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 …

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Inside Unlv, Gian Galassi, Katrina Hudak, Carol C. Harter, Eric Sandgren, Tom Hagge Dec 2003

Inside Unlv, Gian Galassi, Katrina Hudak, Carol C. Harter, Eric Sandgren, Tom Hagge

Inside UNLV

No abstract provided.

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Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore Sep 2003

Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore

Publications (WR)

The Las Vegas Wash (Wash) is the primary drainage for the metropolitan Las Vegas Valley, eventually finding its way into the Colorado River watershed system. Pursuant to the recommendations of the Water Quality Citizens Advisory Committee, the Las Vegas Wash Coordination Committee (LVWCC) was formed in 1998 to develop a comprehensive plan for the long-term stabilization and management of the Wash. Consisting of representatives from 28 government agencies, businesses, environmental groups and citizens, the LVWCC formulated the Las Vegas Wash Comprehensive Adaptive Management Plan (CAMP) and designated the Southern Nevada Water Authority (SNWA) as the lead agency for the implementation …

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The Benefits Of Breastfeeding: An Introduction For Health Educators, Sheila G. J. Clark, Timothy J. Bungum Sep 2003

The Benefits Of Breastfeeding: An Introduction For Health Educators, Sheila G. J. Clark, Timothy J. Bungum

Environmental & Global Health Faculty Research

Currently 16% of Americans breastfeed their children for at least 12 months as recommended by the AAP, which is well below the HP 2010 goal of 25%. Breastfed infants receive benefits that can improve their health throughout their lives. The benefits of breastfeeding for children include increased resistance to infectious diseases, such as gastroenteritis, respiratory tract infections, and ear infections. Breastfed children also display lower rates of chronic diseases including diabetes, obesity, asthma, and leukemia. The choice to breastfeed results in economic benefits from lower health care costs and from reduced spending on infant formula. The Healthy People 2010 targets …

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Inside Unlv, Gian Galassi, Carol C. Harter, Gale Sinatra Aug 2003

Inside Unlv, Gian Galassi, Carol C. Harter, Gale Sinatra

Inside UNLV

No abstract provided.

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Isolation And Characterization Of Thermophilic, Calcium-Precipitating Bacteria Form Calcite Deposits At Yucca Mountain, Terry Ann Else, Curtis R. Pantle, Penny S. Amy, Mark P. Buttner, Amy J. Smiecinski Jul 2003

Isolation And Characterization Of Thermophilic, Calcium-Precipitating Bacteria Form Calcite Deposits At Yucca Mountain, Terry Ann Else, Curtis R. Pantle, Penny S. Amy, Mark P. Buttner, Amy J. Smiecinski

Publications (YM)

Calcite deposits, composed of a mixture of calcium carbonate and silicon dioxide, were found in fractures and small cavities within the welded tuff of Yucca Mountain. This research investigation involves determining the presence of thermophilic, calciumprecipitating bacteria within these deposits. The possible existence of thermophilic bacteria may help to resolve the issue of whether these calcite deposits formed from precipitation of dissolved calcium carbonate in rain water transported from the overlying soil environment or as a result of upwelling of geothermally-heated waters transported from below the mountain. Evidence for microbially-influenced calcite precipitation in these deposits is indicated by the presence …

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Inside Unlv, Kevin Force, Gian Galassi, Carol C. Harter, Stuart Mann Jun 2003

Inside Unlv, Kevin Force, Gian Galassi, Carol C. Harter, Stuart Mann

Inside UNLV

No abstract provided.

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Travel Time Study At The Wetlands Park National Preserve, Brandon Bair May 2003

Travel Time Study At The Wetlands Park National Preserve, Brandon Bair

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis reports on a study of the residence time of water in the Wetlands Park Nature Preserve in Henderson, Nevada. Rhodamine WT was used in order to test for the travel time of the water from the Monson Channel inflow to the Nature Preserve outflow to the Las Vegas Wash. The initial hypothesis was that the water would stay in the system for approximately 8 days. Residence time was tested using an ISCO sampling machine along with a Sequoia-Turner model 450 fluorimeter to test for the fluoresce of the dye in the water. All samples collected were taken immediately …

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Fluctuations In Chinook Salmon (Oncorhynchus Tshawytscha) Counts At Three Lower Columbia River Spawning Sites, Eric Michael Loomis May 2003

Fluctuations In Chinook Salmon (Oncorhynchus Tshawytscha) Counts At Three Lower Columbia River Spawning Sites, Eric Michael Loomis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several hypotheses were developed to explore the pronounced increase in Chinook salmon (Oncorhynchus tshawytscha) returning to spawning grounds at the Cowlitz, Kalama, and Lewis Rivers, three tributaries of the lower Columbia River. The study was conducted using data compiled over a ten-year span from 1991-2001. Preliminary indications are that trends in climate are linked to these increases, with the absence of El Niño events and fluctuations in winter precipitation as likely explanations of these phenomena. The unique nature of Chinook life cycles causes them to utilize a variety of habitats that require ideal conditions for maximum survival rates. Correlations between …

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The 100th Meridian Initiative In Nevada: Assessing The Westward Movement Of The Zebra Mussel To The Lake Mead National Recreation Area, Megan Mccoy May 2003

The 100th Meridian Initiative In Nevada: Assessing The Westward Movement Of The Zebra Mussel To The Lake Mead National Recreation Area, Megan Mccoy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zebra mussels, Dreissena polymorpha, are a concern for all bodies of water in North America. East of the 100th Meridian, zebra mussels have infested the waters and dramatically changed the natural ecosystems. The US Fish and Wildlife Services set up the 100th Meridian Initiative project to monitor the boat traffic to and from infested and non-infested waters of the United States and Canada. Surveys were conducted from October 19, 2002 through March 31, 2003, focusing specifically on the Lake Mead National Recreation Area (LMNRA) for the scope of this thesis. This study addresses the movement of trailers, boats, and other …

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An Analysis Of Materials Suitable For Use As A Pitfall Trap In A Desert Environment, R. Renee Brown Apr 2003

An Analysis Of Materials Suitable For Use As A Pitfall Trap In A Desert Environment, R. Renee Brown

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to identify a type of pitfall trap container that can withstand the temperature extremes of the Mojave Desert in which the terrestrial, or above ground, drift fence with pitfall traps will be utilized for trapping reptiles. A pitfall trap is a container, such as a plastic bucket with a plastic lid, that is buried in the ground up to the lip of the bucket and used to catch small ground dwelling fauna that fall into the trap. Many different pitfall trap materials have been utilized in the trapping of small ground-dwelling fauna. Plastic has …

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On The Relationship Between Stomatal Characters And Atmospheric Co2, C. D. Reid, H. Maherali, H. B. Johnson, S. D. Smith, S. D. Wullschleger, R. B. Jackson Jan 2003

On The Relationship Between Stomatal Characters And Atmospheric Co2, C. D. Reid, H. Maherali, H. B. Johnson, S. D. Smith, S. D. Wullschleger, R. B. Jackson

Life Sciences Faculty Research

Leaf stomatal characters influence the response of terrestrial evapotranspiration to climate change and are used as proxies for the reconstruction of past atmospheric [CO2]. We examined the phenotypic response of stomatal index (SI), density (SD) and aperture (AP) to rising atmospheric CO2 in 15 species after four years exposure to a field CO2 gradient (200 to 550 μmol mol−1 atmospheric [CO2]) or at three Free Air CO2 Enrichment (FACE) sites. Along the CO2 gradient, SI and SD showed no evidence of a decline to increasing [CO2], while AP decreased slightly. There was no significant change in SI, SD or AP …

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Quantifying Ecosystem Geomorphology Of The Southern Appalachian Mountains, Scott R. Abella Jan 2003

Quantifying Ecosystem Geomorphology Of The Southern Appalachian Mountains, Scott R. Abella

Public Policy and Leadership Faculty Research

Geomorphology is a dominant factor influencing vegetation distribution in the southern Appalachians, and quantifying landform characteristics is increasingly important for forest ecosystem classification. This study used slope gradient and two previously published geomorphic indices, terrain shape index and landform index that quantify landform shape and protection, to develop a field-based landform quantification system at four study areas in the southern Appalachians. Six major landform types (ridgetops, nose slopes, linear hillslopes, coves, stream ravines, and stream bottoms) exhibited quantitatively different characteristics, and these differences among landforms were not evident when using only categorical landform descriptions (e.g., convex, concave) that have been …

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Assessment Of Potential Environmental Impacts Of Nature-Based Tours Originating Within Clark County, Nevada, Beth Domowicz Jan 2003

Assessment Of Potential Environmental Impacts Of Nature-Based Tours Originating Within Clark County, Nevada, Beth Domowicz

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this thesis was to assess the potential magnitude of negative environmental damage of nature-based tours originating in Clark County, Nevada. An ordinal ranking system was used for assessment of five variables. These variables were resource use, noise pollution, soil degradation, vegetation degradation, and wildlife disturbance. There were two proposed answers. The first was that as distance increased, negative tour impact would increase. This was not supported, since tours had high impacts for destinations that were close by and far away. The second was that most tours were not causing high damage to the environment. This hypothesis was …

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Kalirin Dbl-Homology Guanine Nucleotide Exchange Factor 1 Domain Initiates New Axon Outgrowths Via Rhog-Mediated Mechanisms, Victor May, Martin R. Schiller, Betty A. Eipper, Richard E. Mains Aug 2002

Kalirin Dbl-Homology Guanine Nucleotide Exchange Factor 1 Domain Initiates New Axon Outgrowths Via Rhog-Mediated Mechanisms, Victor May, Martin R. Schiller, Betty A. Eipper, Richard E. Mains

Life Sciences Faculty Research

The large multidomain Kalirin and Trio proteins containing dual Rho GTPase guanine nucleotide exchange factor (GEF) domains have been implicated in the regulation of neuronal fiber extension and pathfinding during evelopment. In mammals, Kalirin is expressed predominantly in the nervous system, whereas Trio, broadly expressed throughout the body, is expressed at a lower level in the nervous system. To evaluate the role of Kalirin in fiber initiation and outgrowth, we microinjected cultured sympathetic neurons with vectors encoding Kalirin or with Kalirin antisense oligonucleotides, and we assessed neuronal fiber growth in a serum-free, satellite cell-free environment. Kalirin antisense oligonucleotides blocked the …

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Red Rock Desert Learning Center & Wild Horse And Burro Facility: Oliver Ranch Feasibility Study, Yosemite National Institutes Aug 2002

Red Rock Desert Learning Center & Wild Horse And Burro Facility: Oliver Ranch Feasibility Study, Yosemite National Institutes

Oliver Ranch Project

Yosemite National Institutes, a private, non-profit national environmental education leader, has been running successful residential science programs in national parks for 30 years in partnership with the National Park Service. The mission of YNI is to provide educational adventures in nature's classroom to inspire a personal connection to the natural world and responsible actions to sustain it. Early in 2000 in Las Vegas, a new organization, the Outside Las Vegas Foundation (OLVF), was forming. The OLVF is dedicated to preserving the federal public lands surrounding Las Vegas, enriching the experience of its visitors, enhancing the quality of life for local …

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Genesis And Morphology Of Soil Pendants In Quaternary Landforms Of Pahranagat Valley, Nevada, Amy Lynn Brock Aug 2002

Genesis And Morphology Of Soil Pendants In Quaternary Landforms Of Pahranagat Valley, Nevada, Amy Lynn Brock

UNLV Theses, Dissertations, Professional Papers, and Capstones

Five geomorphic surfaces present in the northern Pahranagat Valley, Lincoln County, Nevada range in age from Early Pleistocene to Recent (Q1-Q5) and vary in clast lithology from dolomite to volcanic tephras. Two chronosequences and 5 lithosequences were compared to evaluate micro and macromorphic characteristics and development of soil pendants. This study presents a new interpretation for soil pendant development. Key features observed in the Pahranagat Valley pendants provide evidence for precipitation at the clast-pendant contact suggesting that newer deposits are not always found at the pendant terminus as other studies have assumed. These features include a void at the clast-pendant …

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Comparison Of Water Quality, Zooplankton Density, And Cover In Razorback Sucker (Xyrauchen Texanus [Abbott]) Spawning Areas Of Lake Mead And Lake Mohave, Michael E. Golden, Paul B. Holden, Southern Nevada Water Authority Jul 2002

Comparison Of Water Quality, Zooplankton Density, And Cover In Razorback Sucker (Xyrauchen Texanus [Abbott]) Spawning Areas Of Lake Mead And Lake Mohave, Michael E. Golden, Paul B. Holden, Southern Nevada Water Authority

Publications (WR)

Las Vegas Bay and Echo Bay in Lake Mead have small, self-sustaining populations of razorback sucker (Xyrauchen texanus [Abbot]). Increased productivity and cover have been hypothesized as reasons for successful recruitment of razorback sucker in Lake Mead. Conversely, reproduction has been documented on Lake Mohave, another lower Colorado River reservoir, but no recruitment has been observed. In 2000, BIO-WEST, Inc. was contracted by the Southern Nevada Water Authority to design and implement a study to examine nutrient levels, zooplankton density, and cover in areas with and without razorback sucker recruitment success. We sampled Echo Bay, Las Vegas Bay, and …

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Research Protocol For The Atlantic Bottlenose Dolphin (Tursiops Truncatus): Mirage Click Collection Study, Adrienne M. Cardwell May 2002

Research Protocol For The Atlantic Bottlenose Dolphin (Tursiops Truncatus): Mirage Click Collection Study, Adrienne M. Cardwell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Past research on dolphin echolocation has shown that dolphins can adaptively control the frequency and amplitude of echolocation clicks. The degree to which click production is controlled and the relationship between click variation and echolocation task remains uncertain. This thesis describes a research protocol for studying the adaptive control of dolphin echolocation. The protocol builds on past studies to investigate the manner in which the spectral characteristics of clicks and the overall number of clicks produce for a given task vary in relation to the type of task being performed.

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Arbuscular Mycorrhizae Of Mojave Desert Plants, J. H. Titus, P. J. Titus, R. S. Nowak, S. D. Smith Jan 2002

Arbuscular Mycorrhizae Of Mojave Desert Plants, J. H. Titus, P. J. Titus, R. S. Nowak, S. D. Smith

Life Sciences Faculty Research

Roots of 15 Mojave Desert plant species were assessed for arbuscular mycorrhizal (AM) colonization in spring and autumn 1999. Another 19 species were assessed in autumn only. Perennial species were AM colonized, whereas annual species contained very low levels of AM hyphae or were nonmycorrhizal. The nonnative tree Tamarix ramosissima was also nonmycorrhizal. Levels of hyphae changed over the season in 2 species, arbuscle levels increased in 1 species, and vesicles decreased in 7 species. Mycorrhizal inoculum potential (MIP) was assessed in the soils associated with spring-collected plants. All soils were found to contain MIP. MIP values were not correlated …

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