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Improved Rumen Microbiome Interpretation Via Empirical Filtration Derived From Known Mock Microbiomes, Wesley A. Tom

School of Biological Sciences: Dissertations, Theses, and Student Research

The rumen microbiome plays a critical role in ruminant health and performance. As a consequence, many studies investigate microbial community composition using 16S rDNA based sequencing. As such, data quality and data filtering are critical to accurately identify microbial community composition. In this study we use mock communities to empirically select data filtering parameters to reduce artifact populations and compared the effect of filtering using different bioinformatic pipelines using rumen bacterial community data. The filtering parameters identified provides consistent estimates of rumen microbial diversity, regardless of bioinformatic pipeline utilized and provides a more accurate view of microbiome structure and composition. …

Orchestrated Architecture Dismantling: Borrelia Burgdorferi’S Coordinated Destruction Of Adaptive Immune Responses, Craig A. Land

Electronic Theses and Dissertations

Borrelia burgdorferi represents the most prevalent vector-borne bacteria in North America, affecting ~476,000 Americans annually yet persisting despite robust immune responses. This project reveals spirochetes target adaptive immunity through coordinated lymphatic colonization and precision immune dysregulation.

Using comparative host models (C57BL/6 vs. reservoir Peromyscus leucopus), we demonstrate lymph node colonization within 48-hours, with spirochetes exploiting LYVE-1-positive lymphatic structures as dissemination highways while avoiding the interior of follicular regions. Critically, we identify targeted CD4+ T-cell elimination in germinal center border zones at 21-DPI, precisely when these cells should be coordinating protective immunity. Concurrent upregulation of inhibitory receptor CD32b creates molecular …

Molecular And Clinical Insights Into Role Of Gper In Hepatocellular Carcinoma (Hcc), Hossain Ahmed

Theses and Dissertations

Metabolic dysfunction–associated steatotic liver disease (MASLD), encompassing stages from steatosis (MASLD) to steatohepatitis (MASH), cirrhosis, and hepatocellular carcinoma (HCC), is the most prevalent chronic liver disease worldwide, yet molecular markers of progression remain limited. The G protein–coupled estrogen receptor (GPER), a non-genomic estrogen receptor with metabolic and anti-inflammatory roles, emerges as a candidate regulator in hepatic pathophysiology. In this Dissertation thesis, we have delineated for the first time clinicopathological assessment of liver biopsies across MASLD stages revealing a robust inverse correlation between GPER expression and disease severity. Higher GPER levels in early MASLD associated with favorable metabolic and biochemical profiles, …

Using Livestreaming Technology To Answer Novel Questions About The Behavior And Physiological Ecology Of The Prairie Rattlesnake (Crotalus Viridis), Max C. Roberts

Master's Theses

Recent advances in remote monitoring technology are opening up new opportunities for developing innovative natural history and biological research methodologies. In particular, the emergence of livestreaming camera technology has made recording remote video of wild and secretive animals much easier and made it possible to collect data at extremely fine temporal resolutions. In 2024, Project RattleCam launched a livestreaming camera at a Prairie Rattlesnake (Crotalus viridis) den in Colorado. The goal of this work was to study Prairie Rattlesnake behavior 24-7 throughout the species’ active season with minimal human disturbance. Additionally, I used this system to study the …

Investigating Rattlesnake Social Networks And Improving Their Public Image Through Unobtrusive Technologies And Community Science, Owen M. Bachhuber

Master's Theses

While technology is often blamed for humans’ increasing disconnect with nature, it can also serve as a tool to facilitate empathy and conservation action for wildlife. Snakes are among the most feared animals on the planet, though their understudied social interactions provide opportunities to make scientific discoveries and change public perceptions. Project RattleCam was founded as a camera trap project in 2021 and launched the first off-grid livestream on a den of wild Prairie Rattlesnakes (Crotalus viridis) in 2024. Both camera types captured hundreds of Prairie Rattlesnakes gathering in the summer as they prepared to give birth to pups before …

Groundwater-Dependent Ecosystems In Southeastern Utah: An Integrated Analysis Of Hydrology, Ecology, And Landscape Change, Colten Lay

All Graduate Reports and Creative Projects, Fall 2023 to Present

In Southeastern Utah, springs play a critical role in sustaining groundwater-dependent ecosystems (GDEs) in a semi-arid environment. However, they remain understudied and face growing threats from climate change, land use modifications, and hydrologic alterations. This study addresses knowledge gaps in spring occurrence, hydrologic function, and ecological condition by integrating field surveys, remote sensing, and geospatial analysis across multiple spatial scales. It provides a comprehensive assessment of spring hydrology, water quality, and ecological conditions using field surveys, remote sensing, and GIS analysis to establish a foundational baseline of GDE resources in the region. I applied a multi-scale monitoring approach across the …

Effects Of Elevation, Fire Age, Burn Severity, And Pre-Fire Vegetation On Post-Fire Sagebrush Songbird Communities, William D. Harrod

All Graduate Theses and Dissertations, Fall 2023 to Present

The Sagebrush Biome of western North America has been threatened by a combination of interconnected threats. In the Great and Columbian Basins, a large portion of sagebrush loss has been due to an increase in higher-severity wildfires, caused by invasive annual grasses. As sagebrush declines, numerous wildlife species that rely on the biome have experienced similar trends. Sagebrush-adapted songbirds such as sage thrasher, Brewer's sparrow, and sagebrush sparrow as well as steppe-songbirds, have all experienced population declines. Currently, limited information exists as to how fire severity or recovery affect these songbirds or what resource managers can do to improve their …

Linking Variation In Mule Deer Nutritional Condition And Age To Population Performance In A Temperate Environment, Kent R. Hersey

All Graduate Theses and Dissertations, Fall 2023 to Present

The amount of body fat animals have as they enter and exit winter can have major impacts on how well they survive and reproduce. Mule deer are widely distributed herbivores whose survival and reproduction are strongly tied to weather patterns and the quality of vegetation they consume, which in turn impacts nutritional condition. The objective of this study was to identify and quantify the factors (animal specific, climatic, or habitat) influencing mule deer body fat during both summer and winter in Utah and examine how nutritional condition influences survival. We found December body fat was most affected by December lactation …

Assessing Long-Term Changes In Aspen Forest Cover In Northern Yellowstone National Park Before And After Carnivore Recovery, Nicholas J. Bergeron

All Graduate Theses and Dissertations, Fall 2023 to Present

The recovery of large carnivores (wolves, bears, cougars) in Yellowstone National Park and the subsequent decline of the area's elk herd have raised key questions about ecosystem restoration—particularly for species such as aspen, which are heavily browsed by elk. Following wolf reintroduction in the mid-1990s, scientists began tracking changes in browsing intensity and height of young aspen within sampling plots, assuming reduced browsing and taller stems were signs of population recovery. However, no studies have measured whether the total area covered by aspen stands actually increased, as would be expected with broader recovery. Moreover, the potential influence of climate change …

Ecology And Management Of Forest Grouse: Breeding Acoustic Monitoring, Spatial Behavior, And Harvest, Logan Clark

All Graduate Theses and Dissertations, Fall 2023 to Present

Forest grouse are difficult to study and manage in the Intermountain West because they live in remote, rugged areas and do not gather at predictable display sites like other grouse species. From 2023 to 2025, I studied two species, dusky grouse (Dendragapus obscurus) and ruffed grouse (Bonasa umbellus), to test new survey tools, track their seasonal movements, and evaluate hunting impacts.

First, I tested whether small audio recording devices placed in the forest could minimize labor needed for spring breeding surveys. To do this, I conducted traditional surveys with human observers at the same time and …

Exploring Biotic And Abiotic Drivers Of Ecosystem Properties: The Influence Of Waterbirds And Photodegradation On Wetland Ecosystems, Lindsay Miller

All Graduate Theses and Dissertations, Fall 2023 to Present

Wetlands provide a wide range of valuable ecosystem services: these are benefits from the environment that support human well-being, such as water filtration, fish and bird habitat, and shoreline protection. Despite their importance, wetlands are among the most threatened ecosystems, facing increasing pressure from natural and human activities. To better predict the future of wetlands and guide effective management and restoration practices, we need to understand the various forces shaping their ecological properties. In this thesis, we examined the influence of two forces: waterbirds and photodegradation (the process by which sunlight breaks down plant material). To explore each of these …

What’S The Beef With Agriculture? Evaluating The Effectiveness Of An Agricultural Literacy Intervention On Students’ Attitudes And Knowledge Toward Sustainability And Animal Agriculture, Jenny E. Bennett

All Graduate Theses and Dissertations, Fall 2023 to Present

Agricultural literacy is essential for helping individuals understand how food systems impact their daily lives and society. While most research has focused on students’ knowledge, this study addresses the underexplored role of attitudes—critical predictors of behavior—as outcomes of educational interventions. This research analyzed survey data collected before and after an agricultural literacy intervention delivered to high school students in school-based agricultural education (SBAE) programs. The curriculum focused on sustainability in animal agriculture.

Findings from paired samples t-tests showed statistically significant improvements in students' attitudes (from moderately neutral to more positive) and knowledge scores. Further analyses revealed that demographic factors such …

Impacts Of 4r Nitrogen Management And Water Optimization On Soil Health, Kamaldeep Kamaldeep

All Graduate Theses and Dissertations, Fall 2023 to Present

Farmers in Utah and Idaho are facing growing challenges due to high fertilizer costs, limited irrigation water, and pressure to improve long-term soil health. To better understand current practices and grower attitudes, a survey was conducted in 2020 targeting 5,000 producers of small grains, corn, and potatoes. Although the response rate was low, 146 growers representing over 25,000 hectares of cropland participated. Survey results showed that most growers are open to improving nitrogen and irrigation practices and care about their soil health, even if not all are fully using 4R or precision agriculture methods.

This thesis includes two field studies …

Evaluation Of Novel Biomarkers As Predictive Measures Of Mastitis – Establishing A Relationship With Health Status, Lamb Performance, And Determination Of Prevalence Of Mastitis In Ewes Under Intensive Management, Courtney Berghoff

All Graduate Theses and Dissertations, Fall 2023 to Present

Inflammation of the mammary gland, also known as mastitis, is a prevalent and financially impactful disease in sheep production. The objectives of this survey were to 1) evaluate current testing methods: somatic cell count (SCC), California Mastitis Test (CMT), and bacterial culture, as well as novel biomarkers: lamb performance, milk composition, and udder conformation, for their impact on ewes categorized as clinically healthy or unhealthy under intensive management systems at 15 days in milk (DIM) and 30 DIM, and 2) identify biological markers that are correlated with clinical and subclinical mastitis. Milk, blood, and fecal samples, a visual and physical …

Water Conservation Strategies For Growing Ornamental Plants In Utah Landscapes, Jenny L. Koller

All Graduate Theses and Dissertations, Fall 2023 to Present

When early pioneers settled in Utah, they faced challenges living in a dry region with limited water. They built dams, canals, and irrigation systems by working together as a community to manage their water needs. However, adoption of European landscaping methods, farming and rapidly growing population increased water need while climate change and frequent drought reduced water supply.

Today, Utah is one of the driest states and uses more water per person than most other states in the nation. If things don't change, the state could run out of water by 2060. To address Utah's growing water challenges, this research …

The Pharmacology Of Gpr171 Ligands In The Treatment Of Pain: An In Vitro And In Vivo Preclinical Characterization, Max V. Mcdermott

All Graduate Theses and Dissertations, Fall 2023 to Present

Opioids are addictive, ineffective for long-term treatment, readily produce withdrawal and tolerance, and can cause overdose and death. These properties have contributed to an epidemic of addiction and overdose, which continues unabated in the United States. Therefore, new drugs to treat acute and chronic pain are needed. Opioids bind to receptors belonging to a superfamily of proteins called G protein-coupled receptors (GPCRs). GPCRs are the most commonly targeted proteins among FDA-approved drugs. As such, under-researched GPCRs are a viable source of new targets in the field of drug development. One such underexplored GPCR is GPR171. Studies have demonstrated that a …

Supplementing Tannins To Increase Performance And Reduce Methane Emissions In Cows Grazing On Western Grasslands, Horacio Pedro Blanchard

All Graduate Theses and Dissertations, Fall 2023 to Present

Cattle grazing on U.S. rangelands often rely on a limited diet made up mostly of grasses. As the seasons change from spring to fall, the nutritional quality of these grasses declines, leading to less efficient digestion and higher production of methane—a potent greenhouse gas. In addition, most grass-based pastures lack beneficial plant compounds, such as tannins.

This study explored whether adding natural tannins—specifically, condensed and hydrolyzable tannins from quebracho and chestnut trees—to the diet of grazing cattle could improve how the use efficiency of nutrients and reducing methane emissions from cattle. Over two years, 24 cow-calf pairs grazed in small …

Modeling For Functional Traits In Bluebunch Wheatgrass Using Unmanned Aerial Vehicle (Uav) High-Throughput Phenotyping, Brittany L. Johnson

All Graduate Theses and Dissertations, Fall 2023 to Present

Changing climates and shifts in community composition in the Intermountain West threaten sagebrush-steppe ecosystems, impacting both plants and animals. Restoring native grasses like bluebunch wheatgrass (Pseudoroegneria spicata; BBWG) can help ecosystems resist invasive species and recover from stress and disturbances. As a native cool-season grass, BBWG is widely used in rangeland restoration for the western U.S. Breeding programs for restoration plant materials, such as seeds for ecological projects, often require years or decades of field testing while facing staffing constraints. High- throughput phenotyping (HTP), which rapidly measures observable plant traits, offers a faster solution using drones to capture time-series …

The Effects Of Temperature And Cardiotonic Steroids On Cardiac Function And Metabolism In Snakes, Hannah Wilson

All Graduate Theses and Dissertations, Fall 2023 to Present

The function of the heart provides a window into the physiology of vertebrates and a means of evaluating their response to the stresses imposed by diverse activities. I developed a miniaturized instrument to record electrocardiograms (ECGs), using open-source Arduino technology, that a snake can wear as a backpack. The backpack can also be used when the snake is in a metabolic chamber, to record the metabolic rate and ECG simultaneously. I first used the ECG backpack to record the physiology of snakes under different temperature conditions, to verify that the system worked as expected. the backpack was then used on …

Spatial And Thermal Aspects Of The Ecology Of Three Sympatric Rattlesnakes In The Montane Northern Chihuahuan Desert, Joshua James Mead

Open Access Theses & Dissertations

To understand how animals coexist on the landscape, the individual aspects of a species life history must first be understood. Animals need to find locations that provide the resources they need to survive. Movement, microhabitats, and temperature can alter such areas where animals occur. Understanding animal movements provide important information on space use and microhabitats on the landscape. Ectothermic animals must acquiesce to ambient temperatures or use behavioral modifications to alter their body temperature. The ability to maintain suitable body temperature is essential for physiological function, reproduction, and ability to avoid predation. Research on the variation in a species ecology …

Characterization Of Glyt1 Expression And Glycinergic Circuits, Laura Patricia Montes

Open Access Theses & Dissertations

Glycine is one of the main inhibitory neurotransmitters in the central nervous system. Glycine is regulated by the glycine transporters 1 and 2 (GlyT1 and GlyT2, respectively) in the synaptic cleft. Both transporters participate in glycinergic inhibitory neurotransmission. Moreover, GlyT1 also participates in glutamatergic excitatory neurotransmission. GlyT2 is devoted to caudal regions of the brain and is used as a marker for glycinergic neurons. In contrast, GlyT1 is expressed across the brain in the rostrocaudal axis and is highly associated with GlyT1-positive glial cells. Data from our laboratory has identified GlyT1-positive neurons in the rodent brain. Therefore, we hypothesize that …

Temporal Partitioning And Coexistence Among Four Sympatric Felid Species In The Northern Jaguar Reserve, Kylie Marie Rezendes

Open Access Theses & Dissertations

Coexistence among sympatric carnivores is shaped by behavioral strategies that mediate competition and mortality risk in heterogeneous landscapes. Understanding how sympatric carnivores, such as felids, use space and time in relation to one another requires models that account for both spatial and temporal overlap across landscapes. Models incorporating time-to-event probabilities provide a powerful framework for detecting behavioral dynamics across shared landscapes. This study evaluated the spatiotemporal responses of two apex predators â?? the jaguar (Panthera onca) and mountain lion (Puma concolor) - and two mesopredators - bobcat (Lynx rufus) and ocelot (Leopardus pardalis) - across five years of camera trap …

Phylogenetics And Integrative Taxonomy Of The Lang's Reed Frog Species Complex (Anura: Hyperoliidae: Hyperolius Langi), Dominic Troiani

Open Access Theses & Dissertations

The genus Hyperolius (Rapp, 1842) is the most speciose amphibian genus in sub-Saharan Africa. The genus has a complex taxonomic history because of its extensive intraspecific and interspecific morphological variation, large geographic distribution of many taxa, gaps in sampling, and the discovery of significant cryptic diversity within many species. The goal of this study is to understand the relationships and taxonomy of Hyperolius langi via an integrative taxonomic approach that combines molecular, morphological, and bioacoustics data to clarify the systematics of the geographically widespread species Hyperolius langi. Two mitochondrial (16S and cyt b) and one nuclear (RAG1) gene were used …

Environmental Drivers Of Vegetation Dynamics In Constructed And Natural Wetlands Of The Chihuahuan Desert, Enrique David Garcia

Open Access Theses & Dissertations

Desert wetlands are critical ecosystems that provide water, food, and habitat for many different species at different trophic levels. Additionally, they have the capacity to recharge aquifers, control floods, and purify water, among others. Unfortunately, they have been facing multiple environmental challenges due to different human activities, sometimes with disastrous consequences. There is an urgent need to better understand the structure and function of wetlands of different types and in different biomes in order to conserve, restore, and even create them so we can continue to obtain all the ecological services they provide. In this dissertation, I investigated how environmental …

Evaluation Of A Forest Restoration Strategy On Small Mammals In Southern Pine Ecosystems, Gage R. Grantham, Jessica L. Glasscock, Christopher M. Schalk, Kathryn R. Kiid, Reuber Antoniazzi

Electronic Theses and Dissertations

Industrial forestry replanted historic native pine forests (e.g., longleaf pine [Pinus palustris] and shortleaf pine [Pinus echinata]) to homogenous, high-density plantations consisting of native off-site species (e.g., loblolly pine [Pinus taeda]) after intensive harvesting for wood products. The contemporary forest structure that remains, consisting of off-site overstory compositions, can potentially serve as an ecological bridge to facilitate a gradual transition to a more desirable canopy species, thereby conserving biodiversity and ecosystem function. Understanding disturbance-sensitive small mammal communities from restoration strategies (retention) can help achieve long-term management goals for ecosystem conservation across larger scales. I …

An Evaluation Of Key Components Of Natural Resource Camps, Undergraduate Persistence And Success In Natural Resources, Brandy Bishop

Electronic Theses and Dissertations

This study explores the key components that connect natural resource camps, undergraduate persistence, and overall success through gainful employment within the natural resource industry. The aim of this study was to assess early interest and attitudes towards natural resource career pathways and how education interventions shape students’ career outcomes thus leading to overall success. A longitudinal mixed method design was used combining Conservation Careers Camp survey data (n = 39) with institutional records for Forestry majors (n =655) in the Arthur Temple College of Forestry and Agriculture on the Stephen F. Austin State University campus. Quantitative data was analyzed through …

Effect Of Marination And Storage Time On The Properties And Meat Quality Of Broiler Breast, Mayra Mabel Herrera Rivera

Graduate Theses and Dissertations

Abstract The poultry industry has implemented numerous methods, as marination and aging, to improve meat quality and satisfy consumer demands. Three experiments were developed to assess the effects of vacuum tumble marination and aging on the proteins of chicken breast. These experiments utilized 0.75 % sodium chloride, 0.45 % phosphate, and water in a marinade. In experiment one, 270 fillets were allocated into six treatment groups, each comprising 45 fillets. Six days of storage time were used, marinating and storing the fillets in each group at a temperature of 4°C. Following each day of storage period, the fillets underwent a …

Modeling U.S. Corn Production Archetypes In The Agricultural Policy/Environmental Extender Model To Generate Life Cycle Assessment Inventory Data, Brandon Taylor

Graduate Theses and Dissertations

Corn (Zea mays) is an important crop grown across the US for many uses such as grain for animal feed, bio-ethanol production, food products, and industrial products. Corn is produced in almost every state in the US, but most corn production is concentrated in the Corn Belt Region including Iowa, Illinois, Ohio, Indiana, Minnesota, and Nebraska. Although technologies and production practices are improving corn production efficiency primarily through increased yields (improved land use), corn production at this scale greatly impacts the environment through emissions from fertilizer and pesticide runoff and leaching, soil degradation due to improper field practices, as well …

The Influence Of Retail Display Conditions On Ground Beef Quality And Palatability, Sarah Lynn Shoup

Graduate Theses and Dissertations

The objectives of these studies were to evaluate the impact of retail display case type and muscle type on meat quality attributes, including color, lipid oxidation, texture, and volatile compound profiles, as well as to assess economic implications based on retail color degradation. Case type effects were further evaluated by considering environmental factors such as temperature, air velocity, and relative humidity and their influence on the shelf life of beef patties. An economic analysis was also conducted to estimate the value of patties based on a* (redness) scores at different points during retail display. In Study 1, differences in L* …

Freezing And Shipping Optimization To Increase Quality And Profitability Of Meat E-Commerce, Paul Olaoluwaniyi Dahunsi

Graduate Theses and Dissertations

Freezing remains one of the most reliable methods for preserving meat quality and extending shelf life. However, quality deterioration can still occur due to structural and biochemical changes activated during freezing, thawing, and distribution. Since the COVID-19 pandemic, consumers’ preference for bulk purchasing and online meat shopping has increased, raising questions about the best strategies to balance both quality maintenance and profitability. This thesis aimed to evaluate two key stages where frozen beef is most vulnerable to quality degradation: consumer-level freezing and post-purchase shipping. The objectives were (1) to determine the effects of product size and subsequent consumer freezing practices …