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Paleolimnology And Diatom Taxonomy From Lake Tanganyika, Sristika Adhikari

All-Inclusive List of Electronic Theses and Dissertations

Lake Tanganyika is one of the world's largest freshwater ecosystems, supporting rich aquatic biodiversity and providing several ecosystem services to surrounding communities. Environmental changes such as rising lake surface temperatures, pollution, and land-use alterations threaten the lake’s sustainability. This research examines spatial and temporal variations in nutrient dynamics and primary productivity of Lake Tanganyika using diatom assemblages from multiple locations. Our findings indicate reduced nutrient levels and longer stratification periods in the lake’s central basin during most of the Common Era, as indicated by a remarkable increase in the relative abundance of long, needle-shaped planktonic Nitzschia species. In the southern …

Evaluating The Motivations Of Participants In Online Equine Extension Courses, Sarah Vos

Department of Animal Science: Dissertations, Theses, and Student Research

Traditional program evaluations emphasize participant demographics, knowledge gain, behavior change, and program impact. However, evaluating participant motivation can provide addition insight into why participants enroll in extension programs and help explain participant engagement and persistence throughout a program. The purpose of this study was to evaluate participant motivation in two online equine extension courses and examine potential relationships between motivation, demographics, and course delivery method, and describe participant engagement in Virtual Horse Judging Camp (VHJC). This cross-sectional study utilized convenience sampling of participants in two online equine extension courses, Horse Adult Leader Training and Educational Resource (HALTER) and VHJC. The …

Fibrous Protein Biomaterials: Characterization Of Solitary Bee Silk And Cocoons, And Development Of Recombinant Hagfish And Bee Silk Materials, Oran Wasserman

All Graduate Theses and Dissertations, Fall 2023 to Present

This dissertation explores two complementary aspects of fibrous protein biomaterials: the characterization of understudied naturally occurring solitary bee silk and cocoons; and recombinant expression and biomaterial formation of recombinant hagfish intermediate filaments (rHIF) and a single Osmia lignaria Say (Hymenoptera: Megachilidae) silk protein. Some solitary bee species, which make up about 75% of all bee species, spin silk to construct protective cocoons during development. Despite the importance of silk and cocoons to the solitary bees' life history, their properties remain largely unexplored. This dissertation presents a novel method for isolating and testing individual silk fibers without interfering with the development …

The Influence Of Habitat And Individual Specialization On Mountain Lion (Puma Concolor) Hunting Strategy In A Multi-Prey System, Hannah B. Klugman

All Graduate Theses and Dissertations, Fall 2023 to Present

There is a growing recognition that animal species considered generalists (having a broad and varied diet), are actually specialists, a collection of individuals with different preferences and strategies known as specializations. The diet of a specialist depends on the variety and quantity of available food options, and their own ability to take what they need. Mountain lions (Puma concolor) are known for their ability and tendency to hunt large prey, such as elk (Cervus canadensis) and mule deer (Odocoileus hemionus), but despite the fact they overlap with other potential large prey, like feral horses …

Drought And Diet Breadth: Does Insect Specialization Influence Herbivory When Plants Are Under Stress?, Jakob Palmer

All Graduate Theses and Dissertations, Fall 2023 to Present

Climate change will alter precipitation worldwide, causing more frequent and severe drought events worldwide. Drought affects many ecological processes, including plant-herbivore interactions, which are critical to biodiversity and ecosystem health. A variety of plant characteristics can influence herbivory – such as how hairy, nutritious, or toxic a leaf is – and drought has been shown to alter many of these traits. Unique characteristics of herbivore species are also important: herbivores can either feed on a variety of plants (generalists) or a group of closely related plants (specialists). Specialists can cope with traits of the plants they eat, while generalists are …

History-Dependent Gain Control In The Paraventricular Thalamus: Neural Substrates Of Stress-Enhanced Fear Learning, Michael Martino

MUSC Theses and Dissertations

Post-traumatic stress disorder (PTSD) is characterized by hyperarousal and heightened reactivity that generalize beyond the original traumatic event, yet the neural mechanisms by which prior stress experience biases future fear learning remain poorly understood. Stress-enhanced fear learning (SEFL) is a well-validated rodent model of this phenomenon, in which a severe stressor produces persistent sensitization of subsequent fear acquisition. This dissertation used a 30-day SEFL paradigm to identify the brain-wide functional signature of stress sensitization and to identify candidate neural substrates.

Whole-brain cFos mapping during acute fear acquisition revealed a predominant pattern of suppressed neural activity in sensitized animals, with limbic …

Effects Of Beverage Color During Mouth Rinsing On Measures Of Muscular Endurance, Muscular Strength, And Exercise Perceptions During Isometric Handgrip Testing, Sydney Andrews

Exercise Science Theses & Dissertations

Previous research has shown that color can influence psychological responses, physiological responses, and exercise performance. These effects have been previously attributed to learned associations or expectations which may influence exercise-related outcomes. This study aimed to investigate whether beverage color influences muscular performance during intermittent isometric handgrip exercise. This randomized, single-blind, deceptive crossover study consisted of 34 physically active adults (21.9±3.1 years) who completed a handgrip endurance test under three conditions: red beverage rinse, clear beverage rinse, and no-rinse. Participants were informed that the study would examine the effects of mouth rinsing two commercially available carbohydrate containing sport drinks on muscular …

Long-Term Spatiotemporal Change In Coral Reef Fish Populations And Communities In The Philippines, John Christopher Whalen

Biological Sciences Theses & Dissertations

The Visayas Region of the Philippines is a global epicenter of marine fish biodiversity. Hypotheses attribute this peak of species richness within the Coral Triangle to processes that occur at geological time scales. However, changes in biodiversity may occur on ecological time scales, allowing for the assessment of the potential impact of anthropogenic activities. Recent declines in genetic, species, and ecosystem diversity have been observed in the tropics, including the Philippines. Within the Philippines the Visayas Region is considered the epicenter of species adversity due to anthropogenic stressors such as habitat degradation, overfishing, and harvesting individuals for the aquarium trade. …

Computational And Ai Tools For Understanding Telomere-Associated Cancer Mechanisms, Eleni Adam

Computer Science Theses & Dissertations

Telomeres are the protective caps of the human chromosomes and are critical for genome stability. Dysfunctional telomeres caused by their erosion with age and cell proliferation as well as by defects in their maintenance is a major early event leading to genome changes and cancer. Subtelomeres possess the critical role of regulating adjacent telomeres. Due to their complex repeat structure and high variance from one person to another, these areas have not been analyzed in detail. We present a set of computational and machine learning tools to aid in the understanding of subtelomere structure and its rearrangements in cancer.

Initially, …

A Geometric Morphometric Analysis Of Acetabular Shape Variation Across Bat Families, Jordan L. Huff

Electronic Theses and Dissertations

Bats are the only mammals capable of powered flight, and research is concentrated on this adaptation. Their non-flight locomotion has received comparatively little attention. Previous studies show that non-flight locomotor behaviors vary across families. Members of Pteropodidae are efficient climbers but cannot effectively walk, whereas Phyllostomidae and Vespertilionidae are better at terrestrial locomotion but show reduced arboreal capabilities. The non-flight locomotion of Hipposideridae and Rhinolophidae is less understood, although rhinolophids exhibit limited terrestrial locomotion. This study examined whether differences in locomotor behavior are associated with variation in acetabular morphology. A geometric morphometric analysis of acetabular shape was conducted across multiple …

Divergent Belowground Strategies Of Savanna Grasses Under Varying Fire Regimes, Abigail C. Schmidt

All Graduate Theses and Dissertations, Fall 2023 to Present

Savannas are unique ecosystems, where trees and grasses live together across the landscape, not quite forming full forests or open grasslands. The ability for trees and grass to coexist is largely the result of widespread disturbances, such as fire. Fire in savannas is largely thought of in how it maintains plants above ground, however, fire also plays a key role in ecosystem and plant processes belowground. First, fire can change how soil nutrients, namely phosphorus, are cycled. Phosphorus is a key nutrient that plants need to function, and plants acquire phosphorus through their roots. Frequent fire can enhance phosphorus availability, …

Agronomic And Economic Evaluation Of Alternative Forage Crops Under Irrigation Technologies And Deficit Irrigation, Shikha Sharma

All Graduate Theses and Dissertations, Fall 2023 to Present

Water is becoming more limited in the western United States, including Utah, so farmers need forage crops that can produce well while using less irrigation water. This study examined how different forage crops respond to reduced irrigation and different irrigation application methods, and whether some crops can provide better economic returns under limited water conditions.

Field studies were conducted at three Utah locations, Cedar City, Logan, and Vernal, from 2020 to 2024. The alternative forage crops included teff, sorghum-sudangrass (sudex), and forage rye. For economic comparison, conventional forage crops included alfalfa, corn, and three-way small grains. Four to five irrigation …

Understanding The Impact Of Environmental Change On Shorebird Abundance And Distribution Across The Intermountain West Over The Past 30 Years, Sharon Montecino

All Graduate Theses and Dissertations, Fall 2023 to Present

Shorebirds have declined worldwide over the past century, mainly due to wetland loss and degradation. Wetlands are sites that are temporarily or permanently flooded and provide critical habitat for shorebirds, especially in arid and semi-arid regions such as the Intermountain West. However, climate change and human water use threaten these wetlands, and how these threats may affect shorebirds in this region remains poorly understood. In the early 1990s, shorebird counts at over 160 wetlands across the Intermountain West provided a broad assessment of shorebird populations in the region. These counts remained the only large-scale surveys until 2022, when the Intermountain …

Integrating Space Use And Demography To Support Management Of An Endangered Alpine Ungulate, Danielle J. Berger

All Graduate Theses and Dissertations, Fall 2023 to Present

The places animals choose to live affect the food they find, the dangers they face, and the weather conditions they experience. These experiences influence whether individual animals survive and reproduce, which in turn affects the size and health of animal populations. Although scientists have long believed that animal movements play an important role in population trends, there has been limited real-world evidence showing this connection. Advances in GPS tracking technology now allow researchers to follow animals over long periods and better understand how movement influences survival. Using 20 years of GPS tracking data from the endangered Sierra Nevada bighorn sheep …

Carbon Cycling, Salinization, And Long-Term Water Quality Trends In Rocky Mountain Streams, Allyson J. Marrs

All Graduate Theses and Dissertations, Fall 2023 to Present

Humans have greatly affected streams and rivers worldwide through urbanization, agriculture, and water use. The purpose of my dissertation is to increase our understanding of various human impacts on rivers. In chapter two, I aim to determine whether there are differences in greenhouse gas (GHG) emissions between a natural river and manmade canals. I did this by measuring the emissions and dissolved concentrations of three of the most prevalent GHGs, carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). I found that most of the sites I studied were emitting CO₂ and CH …

Integrated Soil-Water Processes And Irrigation Management For Agricultural Water Optimization In Semi-Arid Regions, Tejinder Singh

All Graduate Theses and Dissertations, Fall 2023 to Present

Water is one of the most important resources for agriculture in the western United States. In semi-arid regions, farmers depend on irrigation to grow crops, but water supplies are becoming less reliable because of drought, declining snowpack, groundwater depletion, and increasing competition for limited water. Improving agricultural water use is therefore not simply about applying less water. It also requires understanding where water goes after it enters a field, how long it remains available to crops, and how farmers can use that information to make better irrigation decisions. This dissertation follows water through irrigated agricultural systems to better understand how …

Understanding Agricultural Irrigation Practices Along Utah's Wasatch Front Through Farmer-Reported Data, Garland Ledbetter

All Graduate Theses and Dissertations, Fall 2023 to Present

Water is a growing concern in Utah, especially along the Wasatch Front, where cities, farms, and communities all rely on the same limited water supply. Agriculture uses a large portion of the state’s water, so understanding how farms manage irrigation is important for statewide water planning. Utah currently uses a dataset called Water-Related Land Use (WRLU) to estimate agricultural water use across the state. This dataset provides useful information about irrigated land and crop types. However, it does not capture many of the day-to-day decisions farmers make when managing irrigation.

To better understand irrigation practices, this study surveyed 61 farmers …

Understanding And Predicting Precipitation Characteristics In The United States Through Machine Learning, Numerical Modeling And Measurements, Cody Luther Ratterman

All Graduate Theses and Dissertations, Fall 2023 to Present

Precipitation is one of the most important yet uncertain variables in the climate system. It varies dramatically in terms of timing, accumulation, rate, and phase, depending on location, season, circulation patterns, and atmospheric conditions. Precipitation forecasts, especially snowfall, are essential to supporting drought mitigation and water management in the Intermountain West. Because rainfall and snowfall lead to opposite effects on snowpack, accurately partitioning rain and snow is important to estimate snowpack levels, winter recreation, mountain ecosystems and runoff. The research findings in this dissertation have advanced the understanding and prediction of precipitation and snowpack in the U.S. by addressing the …

The Role Of Individual Specialization In Migration Phenology And How Restored Habits Are Used By Native And Nonnative Fishes, Austin Garner

All Graduate Theses and Dissertations, Fall 2023 to Present

Native fish species around the world have declined due to habitat loss, habitat fragmentation, and the spread of non-native species. Because these problems often happen at the same time and interact, recovery efforts can stall unless they address all of the factors limiting a species' comeback. The June sucker (Chasmistes liorus), native only to Utah Lake, UT, has declined for many of these reasons, though its recovery effort has made significant progress due in large part to a successful hatchery program. Yet, the recovery efforts have not yet been able to establish a self-sustaining population in Utah Lake, …

Nutrient Leaching Under Traditional And Intercropped Cover Crop Fields In Northern Utah, Katherine Hewitt

All Graduate Theses and Dissertations, Fall 2023 to Present

This study examines whether cover crops can be used in Utah and the Intermountain West to improve water quality and reduce contamination due to nutrient leaching from agricultural soils into the groundwater. Cover crops such as grasses, clover, and other seed mixtures can be planted to improve soil health, increasing the soil’s ability to retain water and nutrients, which reduces the amount of nitrate and phosphate fertilizers lost through leaching and contamination. In Utah, short growing seasons and limited irrigation water availability hinder the ability to establish cover crops. By planting the cover crop between the rows (intercropping) when the …

Integrative Taxonomic Analysis Of Cryptic Species Diversity In The Spiny Witch-Hazel Gall Aphid, Hamamelistes Spinosus (Hemiptera: Aphididae: Hormaphidini) In Eastern North America, Gavin Andrew Powell Munson

All Graduate Theses and Dissertations, Fall 2023 to Present

Taxonomy is the practice of identifying, classifying and categorizing species, providing structure for the vast diversity of life. Aphids are an ecologically important group of soft-bodied insects, but they can be difficult to identify because of their tiny anatomical size, reduced or simplified morphological features, and morphological variation within a single species across different generations. In this study, the taxonomy of the spiny witch-hazel gall aphid, Hamamelistes spinosus, is revised. The complex multi-generational life cycle of the aphids, which alternates between witch-hazel and birch trees, has led to confusion regarding past descriptions. Scientists in the late 1800s who were …

The Role Of Phenotypic Plasticity And Bet-Hedging In Coping With Unpredictable Temperature Fluctuations In The Marine Annelid Ophryotrocha Labronica, Gabrielle Dawn Newton

Biological Sciences Theses & Dissertations

Coastal ecosystems are increasingly exposed to unpredictable temperature fluctuations, potentially favoring strategies that buffer populations against environmental uncertainty. This study examines how phenotypic plasticity and diversified bet-hedging contribute to variation in life-history traits under differing thermal predictability in the marine annelid Ophryotrocha labronica. After three generations at 24 °C, broods were reared for three generations under four thermal regimes: constant 24 °C (C24), constant 27 °C (C27), predictable fluctuations (Fp), and unpredictable fluctuations (Fu). Survival was assessed before and after acclimation to evaluate selective pressure among regimes. Age at maturity, fecundity, and growth rate were used to quantify plasticity (trait …

Menopausal Symptoms, Psychosocial Factors, And Physical Activity Among Physically Active Midlife Females, Ella Onsoriasl

Exercise Science Theses & Dissertations

Menopausal symptoms are common during midlife and may be associated with females' physical activity (PA) participation, yet how these symptoms relate to PA levels, perceived confidence and enjoyment, and psychosocial resources such as social support (SS), exercise identity, and quality of life (QOL) remains unclear. The purpose of this study was to examine how menopausal symptom severity relates to PA levels, perceived confidence and enjoyment during PA, and psychosocial factors, including SS, exercise identity, and QOL. This cross-sectional study surveyed 151 midlife females aged 40 to 60 who reported engaging in intentional PA at least once per week. Participants completed …

Time-Frequency Analysis Of Arterial Pulse Signals Of Cardiovascular Disease Patients Measured By A Microfluidic-Based Tactile Sensor, Md Mahfuzur Rahman

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents a single-degree-of-freedom (SDOF) based time–frequency analysis framework that can simultaneously extract a comprehensive set of cardiovascular autonomic indices from arterial pulse wave recordings obtained at rest and post-exercise, supporting non-invasive monitoring of autonomic recovery during cardiac rehabilitation. The framework rests on three technical contributions.

First, an SDOF analytical model of motion artefacts quantifies two physically distinct distortion mechanisms: additive baseline drift and Time-Varying System Parameter (TVSP) generated distortion of the Tissue-Contact-Sensor (TCS) stack. Baseline drift is slowly varying and removable by filtering; TVSP distortion rides on all harmonics of the true pulse signal and cannot be removed …

Pre-Post Changes In Physiological, Cognitive, And Motivational Outcomes Following An Active Video Game Intervention In Adolescents And Adults: A Pilot Study, Ashley Williams, Danielle D. Wadsworth, Thaangiah Geetha

Publications

Active video games (AVG) are emerging as a promising home-based strategy to increase physical activity by integrating movement into interactive gameplay. However, evidence remains limited regarding their effectiveness across physiological, cognitive, and motivational outcomes in adolescents and adults within household settings.

A Comparison Of Survival, Growth, And Stress Resilience In Three Different Lineages Of The Pacific Oyster (Crassostrea Gigas) Farmed On The California Central Coast, Victoria F. Hanshaw

Master's Theses

Aquaculture of Pacific oysters on the US West Coast is routinely impacted by seasonal unexplained mortality events. To better understand these large-scale mortality events in oyster aquaculture, shellfish growers and scientists in California have partnered together to conduct comparative, multi-estuary farm trials of discrete Pacific oyster (Crassostrea gigas) lineages. In this thesis we investigate how the more recently imported Midori lineage performs compared to the historically used Miyagi lineage, as well as a Hybrid (Midori x Miyagi) lineage. As part of a 7-month long field study from April-November of 2024 in Morro Bay and Tomales Bay, California, we evaluated …

The Effect Of Specialty Malt On Dry-Hopping, Alexander Kivela

Master's Theses

Dry-Hopping is a modern and ever-increasing method to add hoppy flavors to beer. This is typically seen in pale ales and India Pale Ales (IPA’s). Most research has investigated the effect of dry-hopping only using pale malt, whereas most breweries used specialty malts to create a malty backbone to their beer.

The objectives of this research were to analyze the impact of specialty malts and their concentration on the efficacy of hop flavor and extraction, determined via gas chromatography and sensory analysis. Gas chromatography analysis was modeled after the ASBC Method Beer-48. Sensory analysis was performed via the 15cm line …

Comparative Assessment Of Developmental Fidelity In Hpsc-Derived Neural Crest Cells, Michael H. Zepeda

Electronic Theses, Projects, and Dissertations

Neural crest cells (NCCs) are a transient, multipotent cell population that contributes to craniofacial structures, peripheral neurons, melanocytes, and smooth muscle. Defects in NCC development underlie a broad range of congenital disorders known as neurocristopathies. Human pluripotent stem cell (hPSC)-derived NCCs provide an evaluable model for studying early human development; however, existing differentiation protocols produce variable outcomes, and no standardized method consistently generates high-fidelity NCC populations. To address this challenge, we compared five published hPSC-to-NCC differentiation protocols using the H9 human embryonic stem cell line. We hypothesized that specific protocols more faithfully recapitulate neural crest development through coordinated regulation of …

The Aggregation Of Microplastics By Enhancing Extracellular Polymeric Substance Production In Pseudoalteromonas Sp. Ncimb 2021 To Improve Removal Efficiencies In Environmental Matrices, Janelle L. Mercer

All Theses

Microplastics (MP) are ubiquitous in the natural environment and are a growing threat due to their small size and durability. Plastics are released into the environment through improper waste management, wastewater treatment outfalls, industrial spills, agricultural runoff, and landfills. These particles breakdown into secondary MP through degradation pathways. MP, less than 5 mm, require intricate removal techniques from water systems. Filtration techniques, though viable and effective, have implementation constraints due to high cost, maintenance demands, and filter fouling. By integrating coagulation and flocculation processes prior to filtration, MP removal efficiencies can increase, while minimizing operational challenges during filtration. Extracellular polymeric …

Can Kinematics Specify Tool Use Affordances?, Tyler Duffrin

All Dissertations

Object properties such as length, shape, and heaviness, as well as affordance-based properties such as strike-with-ability and poke-with-ability, can be perceived via dynamic touch as functions of inertia tensor invariants. The primary question addressed here was whether people can perceive these same power and precision properties for purely virtual objects, which lack dynamic physical forces. The Kinematic Specification of Dynamics (KSD) principle asserts that missing dynamics are lawfully specified by kinematic (visual) motion patterns, such that kinematic information alone may support successful interactions with virtual objects. In three experiments, we investigated (1) whether virtual reality (VR) users could calibrate to …