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A Historical Ecology Of Aridland Springs In Desert National Wildlife Refuge, Nuwu/Nuwuvi (Southern Paiute/Chemehuevi) Ancestral Territory, Nevada, Yarrow Sarah Valentine Geggus

Dissertations and Theses

Aridland springs are among the most threatened ecosystems in the world. Vital to desert ecologies and Indigenous cultures, these complex and individualistic ecosystems have layered histories. To inform management in the changing landscape of Desert National Wildlife Refuge, a 1.6 million acre protected area in Southern Nevada, I conducted a historical ecology study of a sample of ten upland springs. Through a six-part interdisciplinary methodology including interviews, archaeological survey, botanical survey, and archival research, I summarize findings into three broad eras: the Nuwu/Nuwuvi pre-Contact Era, the Settler Era, and the U.S. Fish and Wildlife Service Era.

For millennia, Nuwu/Nuwuvi drank …

Pharmaceuticals And Personal Care Products In Pacific Northwest Coastal Ecosystems: Spatial Variation, Organism Effects, And Consumer Perspectives, Amy Lynne Ehrhart

Dissertations and Theses

Anthropogenic pollution poses a threat to marine organisms and ecosystems worldwide. Common chemical pollutants that enter the marine environment include legacy contaminants, which are well known and heavily regulated or banned pollutants, and emerging contaminants, which are more recently recognized as pollutants and often lack regulatory limits for their use and discharge. Wastewater treatment plant (WWTP) effluent is a major source of various contaminants of concern, particularly pharmaceutical and personal care products (PPCPs) that are not fully removed during treatment. PPCPs exist at low concentrations in the environment and may have unknown and subtle effects on marine life. Data gaps …

Investigating Dose-Dependent, Multi-Generational, And Strain-Specific Effects Of 17Α-Ethynylestradiol Exposure In Zebrafish (Danio Rerio), Decatur Mitochondria Foster

Dissertations and Theses

Endocrine disrupting chemicals (EDCs) pose a threat to biodiversity at the individual, population, and ecosystem level, as they can interfere with processes that are responsible for regulating metabolism, development, behavior, and reproduction in living organisms. 17α-ethynylestradiol (EE2) is a synthetic estrogen and EDC utilized in pharmaceutical and livestock industries, and contaminates waterways worldwide. This research explores the effects of dose-dependent and multi-generational exposure of EE2 in three strains of zebrafish. High dose (10-25 ng/L EE2) exposure led to complete reproductive failure, as well as significantly decreased survival and growth. A period in clean water (depuration) after exposure allowed for some …

Aligning Food Environments With Institutional Values: A Mixed Methods Study Of Oregon Health Care Organizations, Elizaveta Walker

Dissertations and Theses

A major driver of the obesity epidemic is obesogenic food environments, characterized by nutrient-poor and energy-dense foods that saturate the collective physical, economic and sociocultural conditions that influence nutritional status. Food environments in organizations such as hospitals and public health agencies warrant special consideration given their health-focused mission. Improving food environments within health care settings has been highlighted by the Centers for Disease Control and Prevention (CDC) as one of seven key strategies to prevent obesity. However, most of the refereed literature examining healthy food environment policies (HFEPs) within hospitals focuses on the inpatient dietary environment, leaving a paucity of …

Do Fungal Symbionts Of Salt Marsh Plants Affect Interspecies Competition?, Vanessa Robertson-Rojas

Dissertations and Theses

The effects of arbuscular mycorrhizal fungi (AMF) as salt marsh plant symbionts may have significant effects on landscape scale distribution patterns and plant-related ecosystem functions that are important to estuarine habitats. This work investigates the effects AMF have on Phalaris arundinacea, Deschampsia cespitosa, and Juncus balticus when grown in a common garden experiment. Plants were grown with and without AMF inoculation in both polyculture and monoculture communities and examined for a variety of response variables that represent different competition strategies. Factorial ANOVA analysis revealed a significant three-way interaction among fungal treatment type, community type, and species for …

Battle Of The Buttercups: Investigating Hybrid Zone Dynamics In A Ranunculus Species Complex, Jessica Persinger

Dissertations and Theses

Plants pose a well-known challenge to the biological species concept because hybridization is a common occurrence. Range dynamics have a crucial role in determining whether species are given the opportunity to interbreed or not. Successful hybridization can be of particular concern when considering range-limited species and their persistence. In my thesis research, I examine the apparent hybrid zone between the southern Oregon endemic Ranunculus austro-oreganus, a candidate threatened species due to its limited range, and its widespread congener, Ranunculus occidentalis, whose range spans from California to Alaska. The discovered contact zone was recognized in populations which contained apparent …

Assessing Well-Being Of Asian Elephants (Elephas Maximus) Through Major Events And Transitions, With Development And Aging, And Husbandry Changes, Sharon Stuart Glaeser

Dissertations and Theses

In this body of research, reproductive and adrenal hormones and behavior were used to evaluate individual and group responses to physiological, social, and environmental changes in zoo-housed Asian elephants, considering factors of sex, age, and life stage. Animals experience physiological, social, and environmental changes as part of their natural history and individual life experience. Measures of both positive and negative states are needed to assess the impact of these changes at the individual and group level. Such measures can help us better understand how animals cope with a changing environment, and can help inform management decisions. Through longitudinal analyses of …

Energy Stores And Life-History Transitions In Red-Sided Garter Snakes (Thamnophis Sirtalis Parietalis), Rachel Catharine Wilson

Dissertations and Theses

All organisms must prioritize investment in either reproductive or self-maintenance activities. Despite this established paradigm, our understanding of how organisms choose to prioritize certain behaviors and physiologies over others remains limited. It is likely that an organism's energy status not only influences variation in reproductive effort, but also transitions to and from reproductive activities. My dissertation aims to investigate how energy metrics (body condition index, adipocyte follicle size, and liver glycogen) relate to reproduction and associated life-history stages in red-sided garter snakes (Thamnophis sirtalis parietalis). Chapter two examines if energy metrics differ with migratory status and sex in …

Literatura Viva: Formas De Conocer La Literatura Y Agricultura Desde Chiapas, Jesse Nichols

Dissertations and Theses

Literatura Viva reflects the links between agriculture and literature in Chiapas, Mexico, demonstrating how the ways of knowing the environment which are culturally expressed through literature and the practices of sustainable agriculture are deeply linked. It argues that the experience of the agricultural working class is central not just to a physical movement towards tangible agricultural change but to a society's ability to understand its socio-cultural and natural environment. The thesis first explores indigenous literature, then agricultural practices and finally educational movements which seek to express pluriversal understandings and ways of interacting with the planet. It argues that these understandings …

No Oxygen, No Water: The Unique Physiology Of Annual Killifish Embryos Across Development, Daniel Erik Zajic

Dissertations and Theses

For most vertebrates, an abundance of oxygen is necessary for the production of ATP and the maintenance of cellular homeostasis. The absence of oxygen, even for brief periods, quickly leads to ATP depletion which can lead to irreparable damages to sensitive organs, such as the brain and heart. However, certain vertebrates demonstrate an extraordinary ability to thrive and recover fully from periods of no oxygen (anoxia). The annual killifish (Austrofundulus limnaeus) lives in ephemeral ponds in the Maracaibo basin of Venezuela and their embryos have the remarkable ability to not only survive anoxic periods for months, but also …

Short- And Long-Term Impacts Of A Deliberative Pedagogy In Introductory Biology And Chemistry Courses, Liz Rain-Griffith

Dissertations and Theses

There have been multiple national calls for curricular reform in college-level science, technology, engineering, and mathematics (STEM), including a need to instill democratic skills in students. Democratic skill building can be embedded in STEM classrooms through intentional "deliberative pedagogies" which include skills in: communication, collaboration, and application. We developed and implemented a deliberative pedagogy, Deliberative Democracy (DD), across introductory majors and non-majors biology courses and a majors chemistry course. In two separate studies, I took a longitudinal, qualitative research approach to understand introductory biology and chemistry students' experiences and perceptions of DD. For the first study, I tracked a cohort …

Variability In Historical Fire Patterns Of A Moist Mixed-Conifer Forest In The Northern Blue Mountains Of Oregon, Laura Marie Platt

Dissertations and Theses

High variability in historical fire patterns characteristic to mixed-severity fire regimes is expected to have contributed to a structurally heterogeneous landscape throughout much of the forested ecosystems of the western United States. After more than a hundred years of fire exclusion in the region, many forests have shifted to a more homogeneous structure, which raises concern regarding these forests' ability to sustain expected increases in fire activity with a warming climate. The shift is not uniform across the west, however, and differences in historical disturbance patterns and changes due to land management are not well characterized in forests across a …

Morphology, Taxonomy, And Ecological Niche Modeling Of The Cochabamba Grass Mouse, Akodon Siberiae Myers & Patton, 1989, James George Dunn

Dissertations and Theses

The Cochabamba Grass Mouse, Akodon siberiae, is a small mouse (mean head+body length: 103 mm, N = 22) that occurs in a spatially restricted range in the Bolivian Yungas forests, the cloud forest transition zone between lowland Amazonia and the Andean Altiplano. Like many species in the genus, their appearance is very similar to that of other species in the genus: they are difficult to distinguish from their congeners, and are challenging to identify. In the absence of molecular data, A. siberiae specimens require a thorough and careful analysis of external and cranial features for identification. Furthermore, Akodon …

Sensing Malignancy: Expanding Upon The Nematode Scent Detection Test, Morgan Alexandra Thompson

Dissertations and Theses

With the growing prevalence of cancer worldwide, research has increasingly focused on methods of early detection since the early detection of cancer can dramatically improve health outcomes for affected individuals. Ideally, early detection systems would be highly reliable yet cost-effective and easy to use. Toward development of such a system, Hirotsu et al. (2015), developed a "Nematode Scent Detection Test" (NSDT) that capitalizes upon the attraction of Caenorhabditis elegans nematodes to various tissue samples from cancer patients to detect multiple types and stages of cancer. However, it is currently unknown which G-protein coupled receptors (GPCRs), and/or ligands interacting with theses …

Understanding Institutional, Social, And Ecological Systems Influencing Climate Change Adaptation And Water Governance In Wine Regions: A Comparative Case Study Of Oregon's Willamette Valley, Usa And Tasmania, Australia, Erin Upton

Dissertations and Theses

My research examines how water management decisions create opportunities or barriers to climate change adaptation in wine regions. Water is a critical resource for economic and environmental sustainability in wine grape growing regions. Climate uncertainty presents considerable risk and vulnerability to freshwater resources in wine producing regions where needs for access to water will increase with more frequent climate extremes. Climate adaptation in the wine industry is a complex problem that requires multi-disciplinary approaches. This research aims to strengthen the interface between water governance and technological and viticulture adaptation approaches. Water resources are shared across regions by stakeholders with varied …

Biogeography, Morphology, And Systematics Of The Mountain Cottontail, Sylvilagus Nuttallii (Bachman, 1837), Mammalia: Lagomorpha: Leporidae, Johnnie H. French

Dissertations and Theses

Widespread species often present taxonomic conundrums: are they truly a single panmictic species, or, is the widespread species in fact a polytypic species complex constituted by independently evolving, morphologically or otherwise cryptic species? One such broadly distributed taxon is Sylvilagus nuttallii, with distribution across the western United States, ranging from South Dakota to California, and from Canada to Arizona. The three subspecies constituting S. nuttallii are, however, geographically isolated and it has been hypothesized that they likely constitute independent, species level taxa. However, that study examined only two of the three holotypes, rather than broader geographic and non-geographic variation. …

Recurrent Formation, Low Levels Of Ecological Differentiation, And Secondary Dispersal Facilitate The Establishment And Persistence Of Autopolyploids In Eriophyllum Lanatum, Nicolas Alexander Diaz

Dissertations and Theses

The high rates of polyploidization events in angiosperms is a well-documented driver of diversification and speciation. The consequences of polyploidy--from gene expression up to ecology--and the processes facilitating the persistence of polyploidy in its early establishment in populations are poorly understood. In this thesis, I examined the role of recurrent formation, ecological differentiation, and secondary dispersal via biotic vectors in the maintenance and persistence of an intervarietal polyploid contact zone of Eriophyllum lanatum in Southern Oregon. Sampling 35 total populations, I used a whole chloroplast capture and flow cytometry to determine the diversity and distribution of chloroplast haplotypes and estimate …

From Theory To Practice: Interdisciplinary Science In Undergraduate Education, Brie Tripp

Dissertations and Theses

Science has undergone a major transformation in the 20th and 21st centuries with new fields emerging at the intersection of disciplines, such as bioethics, bioinformatics, and chemical ecology. Yet, opportunities to engage with interdisciplinary science, and the skills needed to work in these fields, are largely absent from undergraduate biology classrooms. As a consequence, students are potentially deprived of opportunities to think interdisciplinarily and engage with real-world issues that often necessitate interdisciplinary efforts. To be informed citizens in society and forward-thinking scientists in the workforce, undergraduate students will undoubtedly benefit from exposure to these interdisciplinary science experiences.

Given these considerations, …

Using Short Chain Fatty Acids To Inactivate Pseudomonas Aeruginosa Biofilms, Stephen Lee

Dissertations and Theses

Abstract

Using Short Chain Fatty Acids to Disinfect Pseudomonas Aeruginosa Biofilms

by

Stephen Lee

Background

The study of bacteria typically focuses on the planktonic or free-living single-cell state that is purely cultured in a laboratory for subsequent growth with appropriate media. Although this traditional way of growing bacteria has been paramount to the understanding of bacterial behavior, physiology, and pathogenesis, bacteria rarely exist as pure cultures of planktonic growth forms in the natural habitat. Bacterial contamination of environmental surfaces, in the form of biofilms, is a prime public health problem and causes numerous infections within the general public. Biofilms are …

Minimum Complexity Echo State Networks For Genome And Sequence Analysis, Christopher John Neighbor

Dissertations and Theses

Increasing viral illnesses threatens global human health and welfare. Due to the distribution of disease and the expense of diagnosis, it is of value to develop portable assays that can detect viral infections early. DNA molecular logic technology offers a portable detection method due to the versatility and stability of DNA and the potential of in situ computation.

Top-down engineering of these chemical logic networks can be difficult due to the difficulties of their implementation using DNA as a substrate. In this work echo state networks, a form of recurrent neural networks, were explored with the motivation that their implementation …

Before And After The Storm: Interactions Between Tree-Fall Canopy Gaps, Plant Phenology, And Frugivorous Lemurs In Masoala National Park, Madagascar, Monica Sue Mogilewsky

Dissertations and Theses

Madagascar is one of Earth's top biodiversity hotspots, with 80% of life on the island considered endemic. Among the endemic species are lemurs, a diverse group of non-human primates. Unfortunately, Madagascar's diversity, including lemurs, is threatened by habitat degradation and loss. Despite intense anthropogenic pressure over the past 50 years, scientists have not detected any lemur extinctions during this period. Some researchers have proposed that lemurs' adaptations to natural disturbances have provided these taxa resiliency against anthropogenic disturbances. Certainly, Madagascar experiences an extreme disturbance regime: the island experiences an average of over three cyclones a year. These cyclones create numerous, …

Lateralized Temporal Integration Properties Of The Mouse Auditory Cortex, Demetrios Neophytou

Dissertations and Theses

Social communication calls are fleeting, rapidly modulating signals and the ability of the auditory system to perceive such transient signals is a remarkable phenomenon. The mechanism by which the auditory cortex (ACx) is believed to be capable of processing these signals is through recurrent connectivity in the cortical circuits. Recurrent connectivity is proposed to be a possible circuit motif that aids in the processing of these transient signals. Recurrent connectivity is believed to have an effect on the temporal fidelity, the ability to follow a modulating signal, and the recurrent activity, sustained activity following stimulus offset, at the level of …

Ecosystem Health In Guánica Bay And La Parguera, Puerto Rico: Remote Sensing Of Ocean Color And Metal Analysis Of Coral Tissue And Surficial Sediments, Jahnelle Howe

Dissertations and Theses

Guánica Bay is an estuary located in southwest Puerto Rico, with a coral reef ecosystem at its periphery. This ecosystem is affected by sediments, nutrients, and contaminants from the watershed through the Bay and into the offshore water. This project evaluates Guánica Bay and La Parguera coastal areas through remote sensing and chemical analysis to assess coastal ecosystem health. The concentration of metals in two coral species and their associated surface sediments was were analyzed by X-ray fluorescence (XRF) and Direct Mercury Analyzer (DMA- 80). Ocean color remote sensing was used to estimate nutrient inputs and phytoplankton biomass through chlorophyll- …

Attention Strongly Modulates Reliability Of Neural Response To Naturalistic Narrative Stimuli, Jason Ki

Dissertations and Theses

Attentional engagement is a major determinant of how effectively we gather information through our senses. Alongside the sheer growth in the amount and variety of information content we are presented with through modern media, there is increased variability in the degree to which we ‘absorb’ that information. Traditional research on attention has illuminated the basic principles of sensory selection to isolated features or locations, but it provides little insight into the neural underpinnings of our attentional engagement with modern naturalistic content. Here, we show in human subjects that the reliability of an individual's neural responses with respect to a larger …

Mechanisms Of Value-Biased Prioritization In Fast Sensorimotor Decision Making, Kivilcim Afacan-Seref

Dissertations and Theses

In dynamic environments, split-second sensorimotor decisions must be prioritized according to potential payoffs to maximize overall rewards. The impact of relative value on deliberative perceptual judgments has been examined extensively, but relatively little is known about value-biasing mechanisms in the common situation where physical evidence is strong but the time to act is severely limited. This research examines the behavioral and electrophysiological indices of how value biases split-second perceptual decisions and the possible mechanisms underlying the process. In prominent decision models, a noisy but statistically stationary representation of sensory evidence is integrated over time to an action-triggering bound, and value-biases …

Understanding How Sequence Differences Among Glutamate Transporters Might Contribute To Their Differential Function In Glutamate Clearance In C. Elegans, Irving Estevez

Dissertations and Theses

In the nervous system, high circuit resolution requires efficient post-signaling clearance of the neurotransmitter. Glutamate-mediated neurotransmission involves the release of glutamate (Glu) into the synaptic cleft by the presynaptic cell and binding to glutamate receptors (GluR) on the postsynaptic cell, leading to activation of a signal transduction cascade. Neurotransmission is eventually terminated by Glu uptake via glutamate transporters (GluT). Inefficient Glu clearance is detrimental to precise rapid signaling, can lead to blurring of circuit resolution by inadvertent Glu spillover to nearby circuits, and may even be neurotoxic. While classical views depict synapses as insulated by glia, recent technological advances show …

Lps, A Tlr-4 Agonist And Viper A Tlr-4 Inhibitor Upregulate Phagocytosis Of Zymosan In Bv2 Cells, Sherouk Alzeory

Dissertations and Theses

Microglia cells are the first line of innate immunity defense in the central nervous system (CNS). They play a critical role in maintaining CNS homeostasis by having an active but yet balanced phagocytic activity. However, in various CNS related diseases, microglia cells have been shown to malfunction. In Alzheimer's Disease (AD), hyperactive microglia with impaired phagocytic activity is the main hallmark of this disease, along with the accumulation of amyloid-beta aggregates. Additionally, emerging new studies have suggested a fungal infection etiology to AD, specifically in relation to Candida albicans (C.albicans). Thus, understanding the mechanism of fungal clearance in the …

Impacts Of Vegetation Density And Distance From The High Tide Line On Raccoon Predation Of Diamondback Terrapin Nests In Jamaica Bay, Ny – A Preliminary Study, Zvi Teitelbaum

Dissertations and Theses

Diamondback terrapin turtles (Malaclemys terrapin) have been culturally and economically important since at least the nineteenth century. However, due to overharvesting, this became a species of conservation concern. While extensive data are available to describe its natural history, some conditions that impact nest predation are poorly understood. In this exploratory study, vegetation type and distance to the high tide line were examined to determine their potential impact on predation of diamondback terrapin nests by raccoons. For that, terrapin scented water was used to construct 50 artificial nests at Jamaica Bay Wildlife Refuge. These artificial nests were placed in …

More Than Meets The Eye: A Taxonomic Revision Of The Nearctic Species In The Eye-Gnat Genus Amiota Loew (Diptera: Drosophilidae), Lance E. Jones

Dissertations and Theses

Thorough biotic inventories are still needed even in families as seemingly well-studied as fruit flies (Diptera: Drosophilidae). Drosophilidae have had an outsize effect on the history of biology because of their pivotal role in the study of genetics, development, and evolution. Even with more than a century of intensive study, large gaps remain in our understanding of diversity in this fly family, including well-studied areas such as North America. This thesis presents a taxonomic revision of the Nearctic species of the genus Amiota Loew. Twenty-three species are identified as being new to science for publication at a later date. This …

Effects Of Weak Electric Fields On Long-Term Synaptic Plasticity, Gregory Kronberg

Dissertations and Theses

Transcranial direct current stimulation (tDCS) is a technique where a weak direct electrical current is applied to the scalp with the goal of stimulating the brain. There is tremendous interest in the use of tDCS for treating brain disorders and improving brain function. However, the effects of tDCS have been highly variable across studies, leading to a debate over its efficacy. A major challenge is therefore to design tDCS protocols that yield predictable effects, which will require a better understanding of its basic mechanisms of action. One commonly discussed mechanism is that tDCS may alter synaptic plasticity, but the biophysics …