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Sorghum Grain Secondary Metabolites And Underlying Genetics To Reduce Foodborne Pathogens In Poultry, Maria A. Conti

All Dissertations

The rise in antibiotic-resistant pathogens poses a threat to the poultry industry's ability to maintain animal health, prompting growing interest in alternatives to synthetic antibiotics. The use of non-tannin sorghum [Sorghum bicolor (L.) Moench] in poultry rations offers a valuable alternative, as this cereal grain has a high bioactive profile that can provide health benefits, including antimicrobial (AM) activity. The scope of this study was to examine the AM potential of non-tannin sorghum grain against Clostridium perfringens, a major foodborne pathogen that negatively impacts poultry health and production. To that end, the inhibitory effects of a non-tannin sorghum …

Conventional Vs. Regenerative Apple Orchard Management In Michigan, Anthony Poynter

Masters Theses

This study compares the variables and outcomes of a conventional apple orchard and a regenerative apple orchard production system in Kent County, Michigan. The premise is that conventional agriculture relies on high-input systems characterized by synthetic fertilizers, pesticides, herbicides, and fungicides, while regenerative agriculture focuses on long-term soil health, biodiversity, and ecological processes. These differences are important as soil degradation, nutrient loss, and environmental impacts are becoming too significant to ignore. Most research on alternative ways to farm, such as regenerative practices, is focused on annual crops, while perennial orchard systems, especially in the Great Lakes region, have gained limited …

Soil Microbial Responses To Artifical Light At Night, Randall L. Walker

Open Access Theses & Dissertations

Global change, driven by both natural processes and human activities, has significantly transformed ecosystems. Urbanization and artificial light at night (ALAN) are key contributors, disrupting natural light cycles and influencing biological rhythms, biodiversity, and ecosystem functions. Thus far, there remains a gap in knowledge of how soil ecosystems are impacted by ALAN. This study uses a laboratory incubation to investigate the effects of ALAN on soil microbial communities and functions across urban and natural ecosystems. Briefly, soil was collected from eight sites around El Paso, Texas and neighboring New Mexico representing urban and rural light exposure. Soil was then subjected …

Molecular Mechanisms Of Pfas Induced Protein Dysfunction: Implications For Neurodegenerative Risk, Daisy Lee Wilson

Open Access Theses & Dissertations

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with widespread human exposure and well-established links to adverse health outcomes. However, despite increasing epidemiological and experimental evidence, the molecular mechanisms underlying PFAS-induced neurotoxicity remain incompletely defined. This dissertation investigates PFAS toxicity across biological scales, integrating protein biophysics with neuronal cell models to elucidate pathways relevant to neurodegeneration. At the molecular level, we demonstrate that PFAS disrupts the structure and function of globular proteins, including the impairment of α-lactalbumin's calcium-binding capacity and of β-lactoglobulin's retinol binding, through concentration-dependent conformational destabilization. By applying these findings to a neuronal model, we show that …

Mitogenomic And Physiological Comparison Between Wild And Domesticated Congeners, Nicholas Enriquez

Open Access Theses & Dissertations

Domestication is a process in which wild populations are morphologically and/or behaviorally manipulated through selective breeding to become optimized for living in captivity. Consequently, many traits become quickly and significantly diverged from their ancestral, wild lineages, a process known as part of domestication syndrome. Captive breeding of mallards (Anas platyrhynchos) was one of the last major successful domestication events resulting in dozens of recognized breeds today. Many breeds were optimized for either ornamental or agricultural purposes (i.e., meat and/or egg production), but the game-farm mallard was specifically bred for sport hunting. In North America, the use of game-farm mallards to …

Application Of Path Analysis To Determine The Impact Of Age And Sex On The Neural Circuits That Promote Nicotine Withdrawal Severity, Veronika Espinoza

Open Access Theses & Dissertations

The rising prevalence of electronic cigarette (e-cigarette) use presents a major public health concern, particularly in adolescent females who are most susceptible to nicotine use and its long-term negative health consequences. The goal of this dissertation was to utilize preclinical rodent models to understand how group differences in age and sex influence neural activation patterns in brain circuits believed to promote nicotine withdrawal. Prior pre-clinical work, conducted largely in male rodents, has established that there are two major brain pathways that modulate the behavioral effects of nicotine withdrawal. These include the mesolimbic and medial habenula-interpeduncular nucleus (MHb-IPN) pathways. To assess …

Development Of A High-Throughput Framework For Studying Choice-Movement Dynamics In Freely Moving Rats Across Motivational And Pharmacological States, Atanu Giri

Open Access Theses & Dissertations

This thesis develops and applies high-throughput behavioral assays and analysis pipelines to study how external contingencies and internal state shape rodent decision-making. First, it introduces RECORD (Reward-Cost in Rodent Decision-making), a modular platform that combines 3D-printed arenas, microcontroller-based control, and closed-loop trial structure to deliver graded rewards and costs in a foraging-like environment. RECORD supports scalable data collection across multiple arenas and a software stack for parsing, databasing, and extracting spatiotemporal behavioral features and psychometric choice functions. Using this framework, the thesis quantifies how animals integrate sucrose reward magnitude with aversive light cost, revealing structured individual differences and sex-dependent movement …

Prediabetes Prediction Before Disease Onset Using Multimodal Health Data: A Machine Learning Approach, Luisa Veronica Gracia Mazuca

Open Access Theses & Dissertations

Prediabetes is a critical health condition that increases the risk of developing type 2 diabetes. The hemoglobin A1c (HbA1c) test diagnoses patients with prediabetes, but the disease has already caused metabolic alterations. Early detection is essential for timely interventions, and machine learning models offer a promising approach to identify prediabetic individuals through the analysis of biomarkers such as cytokines. We compared four classifiers-logistic regression, decision tree, random forest, and k-nearest neighbors - using cytokines (TNF-α, MCP-1, IL-1β, IL-6, IFN-γ), age, BMI, and waist-to-hip ratio (WHR). Models were evaluated using stratified 5-fold cross-validation and ROC-AUC. K-Nearest Neighbors (k-NN) achieved the highest …

Metabolomics In The Dryland Critical Zone: The Role Of Soil Metabolites In Phosphorus Acquisition, Kalpana Kukreja

Open Access Theses & Dissertations

Earth's Critical Zone (CZ) plays a key role in sustaining life through carbon, water, and nutrient cycling from the top of the canopy to the groundwater. A key feature of critical zone research is the integration of multiple interdisciplinary techniques. An emerging set of techniques that can add to this approach is the field of metabolomics, the quantification and study of comprehensive metabolite profiles. In this dissertation, I apply metabolomics to address knowledge gaps in dryland critical zone ecosystems, specifically how soil metabolite dynamics influence biogeochemical processes, and with a particular emphasis on phosphorus (P) cycling in the Chihuahuan Desert. …

Novel Roles Of G-Beta-Gamma Signaling In Microtubule Dynamics And Neurodegeneration, Diana I. Olivas

Open Access Theses & Dissertations

Neurodegenerative disorders (NDDs), including Alzheimer's disease (AD), are characterized by progressive neuronal dysfunction, cytoskeletal disruption, and cognitive decline. Although Tau hyperphosphorylation and neurofibrillary tangle (NFT) formation are classical hallmarks of AD, emerging evidence suggests that microtubule (MT) dysfunction may precede and occur independently of Tau pathology. Understanding upstream regulators of MT dynamics is therefore critical for elucidating early mechanisms of neurodegeneration. Previous work from our laboratory demonstrated that G protein βγ (Gβγ) subunits directly interact with tubulin and promote MT assembly. However, the mechanism of Gβγ signaling in neuronal cytoskeletal stability and neurodegeneration remained poorly understood. The present study investigated …

Salience Network Circuit Dynamics In Distress Tolerance And Drug-Seeking Vulnerability, Marina Alicia Smoak

Open Access Theses & Dissertations

The psychological distress experienced during drug withdrawal can lead individuals with substance use disorder to abandon their goal of abstinence. Numerous human studies demonstrate that an inability to persist in challenging, goal-directed behavior while experiencing psychological distress is associated with multiple stages of substance use, including relapse. This behavioral construct is referred to as low distress tolerance (DT). Rodent models of DT similarly show that low DT predicts elevated cocaine relapse, particularly when DT is assessed following extended abstinence. This abstinence period corresponds with the incubation of craving, a phenomenon characterized by progressively increased cocaine-seeking over time. Importantly, relapse vulnerability …

High-Resolution Mapping Of Brainstem Feeding Circuits: A Framework For Targeted Neuroscience Tools, Geronimo Tapia

Open Access Theses & Dissertations

The neural control of energy balance is mediated in part by distributed brainstem circuits that integrate metabolic, visceral, and hormonal signals to coordinate appropriate motivated behaviors and autonomic responses. Despite extensive study, the precise neuroanatomical architecture regulating metabolism remains incompletely defined within standardized atlas frameworks. This work addresses that gap through complementary studies examining an acute glycemic challenge methodology known to stimulate feeding, the acute delivery of an anorexigenic-associated neurohormone, and the chemoarchitecture of a major feeding-related region, the parabrachial nucleus. First, utilizing 2-deoxy-D-glucose (2-DG) induced glucoprivation, we map the rapid response of dorsal medullary neuronal populations with high spatial …

Fluoxetine Exposure During Adolescence Alters Prefrontal Cortex Signaling And Nociceptive-Related Behavior In Adulthood, Anapaula Themann

Open Access Theses & Dissertations

The long-term neurobiological consequences of adolescent antidepressant exposure remain poorly understood, despite the substantial increase in selective serotonin reuptake inhibitor (SSRI) prescription rates in youth. Therefore, the goal of this dissertation was to determine whether adolescent exposure to the SSRI fluoxetine (FLX) produces lasting molecular and behavioral adaptations, using rodents as a model system. To do this, in Chapter 2, I assessed whether adolescent FLX exposure (postnatal day [PD] 35-49) alters signaling molecules associated with survival and synaptic plasticity (extracellular signa- regulated kinase [ERK]) within the adult prefrontal cortex (PFC) - a brain region that plays a central role in …

Determining Zap-70 Signaling Pathways Mediated By Ccr7 In Tcr T Cell Activation, Vivian Torres

Open Access Theses & Dissertations

Activation of T lymphocytes is the main event that occurs in the adaptive immune response after engagement of the T cell receptor (TCR) with the peptide of the major histocompatibility complex (pMHC) molecules that are demonstrated by antigen presenting cells [1]. A key step in this process is the recruitment and activation of the zeta chain associated protein of 70 kDa (ZAP-70). ZAP-70 couples TCR engagement to downstream intracellular signaling pathways through phosphorylation of tyrosine residues within intracellular tyrosine activation motifs (ITAMs) [2]. Although there have been extensive studies on the signaling response through TCR activation, the regulatory influence of …

Characterization Of The Antiviral Activity Of Mouse Schlafen Proteins, Wendy Paola Alvarez Leal

Open Access Theses & Dissertations

The goal of this work was to characterize the anti-viral role of mouse Schlafen8 and Schlafen9. Expression of these proteins is induced by type I interferon in response to viral infections. Importantly, their human functional orthologs exhibit anti-viral functions, and the structural element required for these activities are conserved in Schlafen8 and Schlafen9. Therefore, it is expected that these proteins will also impair viral replication. An important limitation in this field is that the anti-viral function of human SLFNs has been evidenced only in in vitro cellular models. No informative mutations have been described in human populations so far. Thus, …

Developing Warning Signage For Harmful Algal Blooms At Lake Fayetteville, Abigail R. Evans

Biological Sciences Undergraduate Honors Theses

The presence of harmful algal blooms (HABs) poses many risk factors for human health, and once microcystin concentration has reached a certain level, that water source will be closed for the duration of the bloom. Agencies tend to use static signage with limited information to inform the public about the current status of the water, but a sign similar to the one used by the National Fire Danger Rating System can allow for constant updates detailing specific risk levels for the public. Using previously reported data on Lake Fayetteville, thresholds for risk factors that are easily measurable were determined. The …

The Genetic Basis Of High Transformation Efficiency In The Model Yeast Saccharomyces Cerevisiae, Mary Kathryn E. Cheek

Biological Sciences Undergraduate Honors Theses

Transformation, a type of horizontal gene transfer, describes the uptake, maintenance, and integration of environmental DNA by cells. Despite the known effects of transformation on evolutionary processes, little is known about the genetic basis of this phenomenon. Saccharomyces cerevisiae is a eukaryote able to transform at quantifiable rates when made chemically competent and treated with a heat shock. S. cerevisiae also has variation in transformation efficiencies between various strains, and high recombination rates allow for sufficient allele “shuffling” in intercross populations. This project utilizes a bulk segregant analysis approach to compare sequencing data between transformant pools and non-transformant pools of …

Exploring Exercise Motivation And Mental Well-Being In College Students, Elaine M. Lindesmith, Anqi Deng Dr

Health, Human Performance and Recreation Undergraduate Honors Theses

This study examined the relationship between physical activity, exercise motivation, and mental well-being among 48 undergraduate students at the University of Arkansas. Guided by Self-Determination Theory, the study used survey data to measure depression, anxiety, physical activity, and open-ended exercise motivation responses. Motivation responses were coded as autonomous or controlled.

Results showed that physical activity was weakly and negatively related to depression and anxiety, but these relationships were not statistically significant. There were also no significant differences in mental health between autonomous and controlled motivation groups, and motivation did not significantly predict mental health outcomes in regression analyses. Overall, the …

Microplastic Composition And Exposure Pathways In Freshwater Systems: A Multi-Matrix Comparison Between Streams And Retention Ponds In Hamilton County, In, Mya Whaley

All-Inclusive List of Electronic Theses and Dissertations

Since the early 1900s, the use of plastics has increased exponentially. The breakdown of plastic materials has exposed all ecosystems to microplastics (small particles of plastic < 5 mm), which are now ubiquitous in natural settings. Microplastics have a relatively large surface area, and many chemicals adsorb to these small particles, impacting their fate and transport of pollution. While microplastics have been found in virtually every setting on Earth, research is necessary to understand their impact on freshwater ecosystems and biogeochemical cycles. The focus of this research was to investigate microplastic compositions in crayfish, sediments, and water samples collected in streams and retention ponds. We analyzed trends in microplastic counts across different land-cover classes, waterbody types, and species, and compared concentrations among matrices to improve our understanding of microplastic exposure pathways in freshwater ecosystems. As a secondary objective, lead and arsenic concentrations were analyzed from sediment samples to investigate metal burdens and compare them to microplastic concentrations. Our findings revealed that, in general, urban streams had the highest microplastic concentrations within land cover categories, and retention ponds had higher microplastic counts than streams. Crayfish, such as F. rusticus had higher microplastic concentrations than F. virilis and F. propinquus, although these results may be influenced by study design. The most common microplastic type was fibers, and most common color was transparent. There was no significant correlation between microplastic and metal concentrations in sediments. We found crayfish to be adequate bioindicators of microplastic pollution, because they were less impacted by environmental variability than sediment and water samples. This research presents the first evidence of microplastics in our study species, F. propinquus, F. rusticus, and F. virlis. This work presents new evidence of microplastic accumulation in crayfish, sediments, and water from freshwater systems in the Midwestern United States. Microplastics were found in every sample type—crayfish, water, and sediment—across urban, rural, and forested landscapes, highlighting their pervasive distribution. The findings provide foundational data for assessing emerging ecological and human-health risks and emphasize the importance of sustained monitoring and research on MP contamination in freshwater environments.

Mechanisms Of Life History Trade-Offs In The Evolution Of Eusociality, Frances Katherine Hunter

All Graduate Theses and Dissertations, Fall 2023 to Present

When faced with stressors such as pathogen infection, organisms must invest energy in defense or risk death. Because resources are limited, mounting an immune response often comes at the expense of other costly activities such as reproduction. The costs of immunity are shaped by factors including behavior, nutrition, age, and evolutionary history.

Social insects (e.g., ants, bees, and wasps) offer a powerful system for studying these trade-offs because queens in these colonies appear to escape them—living long lives while reproducing prolifically. Bees, which include species that range from those which nest solitarily to those with complex social systems and many …

Exploring The Correlation Between Malnutrition And Food And Nutrition Insecurity In Inflammatory Bowel Disease, Heather Burr

All Graduate Theses and Dissertations, Fall 2023 to Present

Inflammatory Bowel Disease (IBD) may increase the risk of malnutrition because of nausea, vomiting, diarrhea and restrictive eating. In addition, patients with IBD may experience food and nutrition insecurity. Therefore, we conducted an online survey to assess risk of malnutrition and food and nutrition insecurity among adult patients with IBD in outpatient and community settings. Patients were recruited between July and December 2025, aiming to reach adults in the Rocky Mountain Region diagnosed with IBD. Data collected included demographics, health-related factors, risk of nutrition insecurity, risk of food insecurity, and barriers and facilitators to dietary management of IBD.

Fifty-seven patients …

Effect Of Agroecological Feeding Systems Of Dairy Cattle On The Nutritional Composition Of Milk, Sree Bhavya Immadi

All Graduate Theses and Dissertations, Fall 2023 to Present

How food is produced can influence both its nutritional quality and its impact on the environment. In recent years, regenerative (agroecological) farming practices have gained attention for their potential to improve soil health, biodiversity, and the nutritional value of foods. In dairy production, these practices often involve growing more diverse forage crops, reducing soil disturbance, and relying less on monoculture-grown feed rations. However, there is still limited real-world evidence showing how these practices affect the nutritional composition of milk produced on commercial dairy farms.

This dissertation explores how regenerative feeding and feed production practices influence the nutritional quality of milk, …

Cross-Facility Reliable Deep Learning Based Beef Marbling Assessment Via Unsupervised Domain Adaptation Regression, Samuel Vinson

Biological and Agricultural Engineering Undergraduate Honors Theses

Inconsistent quality grading in beef production leads to inefficiencies, economic disparity, and consumer mistrust. While USDA meat grading traditionally relies on skilled visual inspectors, these human evaluations suffer from cross-facility variability and subjectivity. This paper introduces the first known application of unsupervised domain adaptation regression for cross-facility beef marbling score prediction—an innovation that improves generalization across diverse environments in the beef supply chain. Utilizing numerical scores ranging from 100-900, the research employed convolutional neural networks (CNNs), including ResNet, VGG, and AlexNet architectures. The study specifically introduced and validated a unified unsupervised domain adaptation regression method using the ResNet-50 architecture to …

Preserving The Past: Exploring The Last Frontier's Ecosystem Shifts And Biodiversity Of The Tallgrass Prairies, Gisell Maldonado, Amelia Villaseñor

Anthropology Undergraduate Honors Theses

In North America, grasslands are a cornerstone of the environment. Historically, the tallgrass prairie was expansive and reached from Manitoba in Canada to Texas. Today this unique ecosystem is highly fragmented and reduced, but it remains an important ecosystem for biodiversity and cattle management. While there are many complex ecological interactions in the prairie, recent research shows that large herbivores are vital in maintaining grasslands through grazing and other behaviors that reduce woody encroachment and support nutrient cycling. Here, we examine cow and bison dietary behaviors and connect these to the ecosystem services provided by these large herbivores. In the …

Effects Of Tourist Feeding On The Gut Microbiome And Ecophysiology Of Endangered Northern Bahamian Rock Iguana (Cyclura Cychlura), Erin Lucy Lewis

All Graduate Theses and Dissertations, Fall 2023 to Present

The lifespan and reproduction of an animal depends on maintaining a healthy physiology. The proportion of individuals that survive to an age at which procreation can occur is important to long-term stability of populations and contributes to species survival. Health in an animal is measured in a variety of ways, including through monitoring of the body’s physiological systems, as well as its ability to respond to invading pathogens, and through the different types of bacteria present in the gut. Relationships among those different health metrics have been discovered in recent years and have been found to play important roles in …

Forage Responses To Biological Inoculant And Seed Rates In The Intermountain West, Roy Reid

All Graduate Theses and Dissertations, Fall 2023 to Present

Improving the efficiency of fertilizer and seed use is increasingly important for forage producers in the Intermountain West, where alfalfa and silage corn form the foundation of dairy and livestock feed. This thesis evaluates two strategies designed to boost crop productivity: microbial fertilizer coatings and variable-rate seeding.

The first study examined whether Powercoat®, a fertilizer-applied microbial inoculant, could enhance yield, forage quality, or soil phosphorus availability in alfalfa grown on four commercial fields in northern Utah. Across all locations, fertilizer increased yield at only two sites, and Powercoat did not provide additional improvements in yield, forage quality, or soil nutrient …

Post-Wildfire Erosion And Biogeochemistry: Integrating Aerial Imagery And Soil Testing To Assess Landscape Recovery, Justin A. Allred

All Graduate Theses and Dissertations, Fall 2023 to Present

After a wildfire, land managers are required to monitor large tracts of land with limited time and budgets. Traditionally, tracking landscape recovery is a time intensive process. This research explored the effectiveness of using drones (UAVs), strategic soil sampling, and computer modeling as additional tools for land managers in order to monitor the recovery more efficiently.

By using drones to collect aerial imagery and using machine learning, plant regrowth was monitored in back-to-back years. The machine learning model performed well at telling broad groups apart (trees vs grass) but it struggled to identify differences between plant species. Because many plants …

Influence Of Predation Risk On Elk Feeding Behavior In A Multi-Predator Environment, Rosemarie C. Pugh

All Graduate Theses and Dissertations, Fall 2023 to Present

Sometimes predators don’t just affect prey by killing them, they can also change how prey behave. For example, animals may spend more time watching for danger and less time eating, which could affect their health and survival. In Yellowstone National Park, past research has suggested that elk may reduce feeding because they are trying to avoid predators like wolves and cougars. However, most previous studies have only looked at elk behavior during the daytime and have often looked at responses from single predators rather than multiple.

In this study, I used high-resolution tracking collars equipped with motion sensors to directly …

Food-Form Delivery Of Spore-Forming Probiotics As An Alternative To Gavage In Animal Models, Aubreyona Faith Migliori Skalka

All Graduate Theses and Dissertations, Fall 2023 to Present

Western dietary patterns are characterized by nutrient-poor, calorie-rich diets and have been linked to poor health outcomes and gut inflammation phenotypes. Probiotics are often taken to support gut health, but many beneficial bacteria do not survive transport through the digestive system to produce any effect. Spore-forming bacteria, such as Bacillus coagulans, are more resilient due to their hardy outer coat which aids in survival through many obstacles encountered in the gastrointestinal tract, including acidic stomach conditions. In research studies, probiotics are usually given to mice through a procedure called oral gavage, where a tube is used to deliver the …

Production Of Hydrolyzed Lactose Syrup From The Acid Whey, Aubrey Jean Arbon

All Graduate Theses and Dissertations, Fall 2023 to Present

Acid whey has gained significant attention within the dairy industry due to its complex matrix and the processing challenges. This by-product contains lactose that can be isolated, hydrolyzed, and further processed to produce hydrolyzed syrup. To optimize lactose utilization, it is essential to fine-tune the kinetics of the β-galactosidase enzymes used for lactose hydrolysis. To analyze sugars in acid whey, and LC-MS-based chromatographic method was developed. Once the method was developed, the kinetics of β-galactosidase were optimized with respect to enzyme concentration, pH, and temperature. The goal was to achieve the highest possible lactose hydrolysis. The hydrolyzed acid whey was …