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Full-Text Articles in Life Sciences

Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca Dec 2013

Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca

UNLV Theses, Dissertations, Professional Papers, and Capstones

An assessment of the growth response of key vegetative species to climatic variability is vital to identifying possible local impacts on ecosystems faced with imminent climate change. With current climate projections in Nevada predicting a shift to an even more arid climate with greater year-to-year variability, the imperative exists to identify the effects of specific climatic controls on plant growth and to research methods to assess large-scale vegetative changes, especially in more remote areas where readily available data sets may be lacking. This study utilized annual growth ring indices constructed from big sagebrush (Artemisia tridentatassp.tridentata) stems collected in Spring ...


Alternations Of Nmda And Gabab Receptor Function In Development: A Potential Animal Model Of Schizophrenia, Monica Bolton Aug 2013

Alternations Of Nmda And Gabab Receptor Function In Development: A Potential Animal Model Of Schizophrenia, Monica Bolton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Schizophrenia is a debilitating mental disorder that affects up to 3% of the world population. The behavioral symptoms are categorized into positive and negative symptoms, which appear during late adolescence/early adulthood. Unfortunately, the underlying cellular and molecular mechanisms of the disease are poorly understood. Several hypotheses exist to explain mechanisms contributing to these behavioral alterations. One model proposes that a reduced function of the NMDA glutamate receptor on specific GABAergic interneurons may be responsible for deficits in schizophrenia. Post-mortem investigations provide evidence of reductions in both glutamate and GABA-related proteins in patients with schizophrenia. Further, GABAergic interneurons that are ...


The Effect Of Temperature Extremes On Cardiorespiratory Function In The Grass Shrimp Palaemonetes Pugio: Oxygen Limited Thermal Tolerance, Teresa Mika Aug 2013

The Effect Of Temperature Extremes On Cardiorespiratory Function In The Grass Shrimp Palaemonetes Pugio: Oxygen Limited Thermal Tolerance, Teresa Mika

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aquatic poikilothermic animals must either cope with or compensate for the mismatch in oxygen supply and demand present at high temperatures. Oxygen limited thermal tolerance explains how aerobic scope is limited by insufficient oxygen supply and sets the performance window in animals. This work explores the effects of temperature on the different components of the oxygen delivery system, in both normoxic and hyperoxic conditions to determine if supplying more oxygen to the system mitigates the effects of temperature effects on the cardiorespiratory system and extends oxygen limited thermal tolerance to higher temperatures. The effect of temperature and oxygen condition was ...


The Effects Of Starvation Selection On Drosophila Melanogaster Life History And Development, Lauren A. Reynolds May 2013

The Effects Of Starvation Selection On Drosophila Melanogaster Life History And Development, Lauren A. Reynolds

UNLV Theses, Dissertations, Professional Papers, and Capstones

In nature, animals may endure periods of famine to complete their life cycles. Starvation stress will increase in populations as climates around the world change. To predict how populations may respond to such a stress, laboratory experimentation becomes essential. The evolutionary process of adaptation, its innovations and their trade-offs, can be studied in populations experiencing starvation stress. For this purpose outbred populations ofDrosophila melanogasterwere selected for starvation resistance in the laboratory.

After 60+ generations of starvation selection the starvation-selected flies have gone from surviving 2-3 days without food to 12-14 days without food. How this amazing feat of resistance is ...


Effects Of Environmental Variables On The Reproduction Of Quagga Mussels (Dreissena Rostriformis Bugensis) In Lake Mead, Nv/Az, Richard Steven Ianniello May 2013

Effects Of Environmental Variables On The Reproduction Of Quagga Mussels (Dreissena Rostriformis Bugensis) In Lake Mead, Nv/Az, Richard Steven Ianniello

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 2007, quagga mussels (Dreissena rostriformis bugensis) were found in Lake Mead and have spread downstream on the Colorado River and to other lakes and reservoirs in the Southwestern United States. The quagga mussel's extremely quick colonization of Lake Mead and annual veliger abundance trends provide evidence that the quagga mussels in the Southwest have different reproductive behavior than in previous habitats. This study is one of the first to specifically examine quagga mussel reproduction in the Southwest and examines how quagga mussel reproduction varies at sites known to have different temperatures and other environmental variables resulting from the ...


Dispersal Ecology Of Desert Mosses Along Gradients Of Elevation, Wildfire Disturbance And Local Niche, Robert Joseph Smith May 2013

Dispersal Ecology Of Desert Mosses Along Gradients Of Elevation, Wildfire Disturbance And Local Niche, Robert Joseph Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Much of the variation in plant communities can be explained by the dispersal of individuals across landscapes, an ecological process that contributes to clinal variation, post-disturbance recovery and habitat occupancy. The role of dispersal is of particular concern for Mojave Desert plant communities that may not be able to tolerate recent departures from historical fire regimes. The aim of this thesis was to infer how dispersal is reflected by patterns of diversity in disturbed and undisturbed bryophyte communities in the Spring Mountains of southern Nevada. Chapter 2 presents an examination of sub-surface bryophyte communities (propagule "soil-banks") along a 1400 m ...


Kinematic Analysis Of Axial Rotations And The Effects Of Stress Selection On Takeoff Flight Performance, Michael L. Brewer May 2013

Kinematic Analysis Of Axial Rotations And The Effects Of Stress Selection On Takeoff Flight Performance, Michael L. Brewer

UNLV Theses, Dissertations, Professional Papers, and Capstones

The importance of flying insects cannot be understated; without them as pollinators, the great diversity of flowing plants could not have occurred. Flight requires a suite of highly derived morphological and physiological characteristics that may limit the evolutionary responses of other life history traits.

To investigate the complexities of maneuvering flight, I used high-speed videography to analyze wing and body motions in the HoverflySyritta pipiens(Order: Diptera) during horizontal turns called saccades. I characterized the saccades by calculating the instantaneous rotational velocities throughout the saccade, maximum rotational velocity, and the mean rotational velocity. I then compared the shape of the ...


Ketamine Induced Deficits In Working Memory With Relevance To Schizophrenia, Michael A. Langhardt, Jefferson Kinney Jan 2013

Ketamine Induced Deficits In Working Memory With Relevance To Schizophrenia, Michael A. Langhardt, Jefferson Kinney

McNair Poster Presentations

Schizophrenia is a chronic debilitating brain disorder, which affects approximately one per­cent of the adult population worldwide. The symptoms of schizophrenia are commonly divided into three broad classes: positive symptoms, negative symptoms, and cognitive disturbances (Kay, et al., 1987). The positive symptoms of schizophrenia include hallucinations, delusions, and dis­organized thinking, while the negative symptoms include affective flattening, social withdrawal, and an inability to plan and carry out future activities. The cognitive disturbances exhibited in schizophrenia include deficits in spatial reference and working memory as well as difficulties with focus and attention (Lewis et. al., 2007). Several models have ...


Are Incomplete Denitrification Pathways A Common Trait In Thermus Species From Geothermal Springs In China?, Julienne J. Paraiso, Brian P. Hedlund Jan 2013

Are Incomplete Denitrification Pathways A Common Trait In Thermus Species From Geothermal Springs In China?, Julienne J. Paraiso, Brian P. Hedlund

McNair Poster Presentations

Temperature has strong impacts on ecosystem function and biogeochemical cycles, particularly within extreme environments such as geothermal springs above 60 °C. The primary focus of this study was to investigate the denitrification pathways of Thermus (Bacteria) isolates from geothermal springs from Tengchong, China. This study tested the hypothesis that incomplete denitrification is a common characteristic of the genus Thermus, regardless of geographic origin or species affiliation, which would implicate them in the efflux of nitrous oxide (a strong greenhouse gas) to the atmosphere. In this study, we cultivated 25 isolates, including six known Thermus species, and measured the stoichiometry of ...


An Acute Inflammatory Response In A Diabetic Alzheimer’S Disease Model, Krystal Courtney D. Belmonte, Jefferson Kinney Jan 2013

An Acute Inflammatory Response In A Diabetic Alzheimer’S Disease Model, Krystal Courtney D. Belmonte, Jefferson Kinney

McNair Poster Presentations

Alzheimer’s disease (AD) is the most common form of dementia, accounting for 50 to 80 percent of all dementia cases. This neurodegenerative disease leads to neuronal death and tissue loss in the brain, resulting in the slow deterioration of memory, thinking skills, and eventually even the ability perform daily tasks. While it is not a normal part of aging, AD is mostly diagnosed in people over the age of 65; thus, the main risk factor for Alzheimer’s disease is increased age, though it is most likely other additional factors also contribute (Heese & Akatsu, 2006). Neuropathological hallmarks of AD ...


A Comprehensive Research Framework For Geographic Parthenogenesis In Whiptail Lizards (Genus Aspidoscelis), Adam Leland Jan 2013

A Comprehensive Research Framework For Geographic Parthenogenesis In Whiptail Lizards (Genus Aspidoscelis), Adam Leland

UNLV Theses, Dissertations, Professional Papers, and Capstones

One of the most compelling topics in biology has been the ubiquity of sexual reproduction in living organisms. Because the ecological and evolutionary advantages of sex are well founded, those organisms that reproduce asexually remain enigmatic. Parthenogenesis, the clonal reproduction of an all-female species without the need for males, is a relatively common form of asexual reproduction in vertebrates, and has been subject of numerous academic investigations. Many parthenogenic organisms also share aspects of their geographic distributions, such as inhabiting higher latitudes, higher altitudes, islands or island-like habitats, xeric environments, and marginal, disturbed or ecotonal habitats relative to their sexual ...