Life Sciences Commons^™

Reconstruction Of Copepod Populations In Sierra Nevada Lakes Using The Diatom Fragilaria Cyclopum, Rorie Reisner

All-Inclusive List of Electronic Theses and Dissertations

Copepods are one of the most abundant types of zooplankton, and their populations are often a vital part of the food chain, but their past populations cannot be estimated from lake sediments because their exoskeleton usually does not fossilize. Gull Lake is a glacial lake located in the subalpine region of the Sierra Nevada, California, which stands out due to the presence of the diatom Fragilaria cyclopum, which is rarer in diatom assemblages. Fragilaria cyclopum exclusively grows on copepods in lakes. Diatoms have an opaline silica skeleton that often fossilizes in lake sediments, so we can use this relationship with …

Reconstructing Stand-Age Structure In A Wet Miombo Woodland Using Dendrochronology, Zambia, Clara Tiyembekeze Zulu

All-Inclusive List of Electronic Theses and Dissertations

Dendrochronological research in tropical Africa has remained limited, leaving critical gaps in stand-age structure and climate-growth relationships in seasonally dry tropical woodlands. This study reconstructed stand-age structure and assessed climate sensitivity in the wet Miombo woodland of African Explosives Limited (AEL) forest, Copperbelt Province, Zambia. Field sampling was conducted during four African Dendrochronology Fieldschools (2021-2024) using a Modified Variable Area Transect (MVAT) design across nine plots. The series intercorrelation was 0.351; the average mean sensitivity was 0.423. The oldest tree was 170 years old, and more than 70% of the sampled species showed potential for dendrochronology. Markhamia obtusifolia was the …

Trace Element Concentrations In Tissues And Otoliths Of Fishes From Artificial Reefs In The Northern Gulf Of Mexico: The Role Of Size, Age, And Trophic Position, Blaine Savoie

LSU New Orleans Theses and Dissertations

Nearshore artificial reefs and fishes relying on them to forage and refuge can be susceptible to trace element (TE) pollutants from anthropogenic sources. Although some TE are essential, higher concentrations can cause detrimental effects and concern regarding consumption. This study assesses TE accumulation in nearshore reef fishes in the northern Gulf of Mexico, a region influenced by coastal riverine discharge, where fishing has socioeconomic importance. Five fish species from six eco-reefs were collected and analyzed for TE. An inductively coupled plasma mass spectrometer was used to analyze the TE concentrations of muscle, liver, and otoliths. TE concentrations of tissues and …

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 …

The Relationship Between Depression And Cognitive Proficiency Index Across Biological Sex, Angela N. Ferdinardo

Dissertations

Depression is a widely studied mood disorder, and understanding its effect on cognitive functioning has become an important area of research. While research has examined relationships among depression, working memory, and cognitive deficits, limited research has explored depressive symptoms and cognitive proficiency across biological sex. Depression manifests similarly in men and women, though men are more likely to experience irritability, impulsivity, and anger, while women tend to experience sadness, stress, and sleep disturbances (Johns Hopkins Medicine, 2023). Women are also more likely to seek treatment and cope differently than men. This study examined the relationship between depression and cognitive proficiency …

Physiological, Cognitive, Behavioral, And Perceptual Contributors To Falls Risk Across Middle And Older Adulthood, Jacquelyn Moxey

Rehabilitation Sciences Theses & Dissertations

Falls are multifactorial events influenced by physiological, cognitive, behavioral, and perceptual factors. Although falls prevention research has traditionally focused on older adults and objectively measured physical impairments, less is known about how cognitive performance, physical activity, and perceptions of ability collectively contribute to falls risk vulnerability across middle and older adulthood. This dissertation examined these relationships through three complementary studies.

Study 1 examined associations between cognitive screening performance and physiological falls risk in 315 community-dwelling older adults. Lower global cognitive performance was associated with greater physiological falls risk. Performance on items reflecting attention and visuospatial/executive function demonstrated the strongest domain-level …

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, …

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, …

Microbes In Pollination Systems: Effects On Pollinator Health, Floral Traits, Nectar Robbing, And Plant Fitness, Valerie Nicole Martin

All Graduate Theses and Dissertations, Fall 2023 to Present

Flowers produce nectar to attract pollinators, but nectar is also a habitat for yeasts and bacteria that arrive via pollinators, robbers, and other visitors. These microbes consume nectar sugars and release byproducts that change the smell and taste of nectar. Whether these changes affect how pollinators find and choose flowers, and whether they ultimately affect how many seeds a plant produces, is not well understood. In this dissertation, I studied how a common nectar yeast and a plant-associated bacterium affect the scent of wildflowers, the behavior of bumble bees and hummingbirds, and plant reproduction in montane meadows in central Colorado. …

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, …

'Fast' And 'Slow' Water Handling Strategies Explain Pinyon Pine Decline And Juniper Expansion, M. Faraz Rehman

All Graduate Theses and Dissertations, Fall 2023 to Present

Across the western United States, pinyon and juniper woodlands are changing with pinyon pine trees dying back while juniper becoming more abundant. Previous studies suggested that pinyon may lose more water during drier periods. But water loss is only part of the story. Water inputs, or how plants absorb water, are also likely to be important, but rarely well understood. To better understand this, we measured how pinyon and juniper absorb water from different soil depths and how actively they lose water through their leaves. Measurements were made over two years at three sites that ranged from more dry to …

The Evolution Of Hymenopteran Recombination Rates, Timothy John Delory

All Graduate Theses and Dissertations, Fall 2023 to Present

Individuals of some species mix their DNA frequently when producing sex cells, while others do so much less. Hymenopterans (ants bees and wasps) are especially useful for understanding this variation for several reasons. They show large differences in this frequency of shuffling, or rate of recombination, have well-studied genomes, and vary widely in how they live and reproduce. I capitalized on these features examines how recombination rates have evolved in this group at the trait, and gene level.

First, I revisited long-standing ideas about why recombination rates differ among these species, incorporating more than a decade of new research. This …

Validating The Expression Of Genes Potentially Involved In The Development Of Aggressive Melanoma Tumor In The Zebrafish Melanoma Model, Mayra Matos Diaz

Theses, Dissertations and Culminating Projects

Melanoma is an aggressive form of skin cancer characterized by rapid progression, metastatic potential, and the frequent development of resistance to targeted therapies. Although the Inducible cAMP Early Repressor (ICER) has been identified as a potential tumor suppressor in melanoma, the molecular mechanisms underlying its role in tumor progression remain poorly understood. Building upon the transcriptomic findings of Wheelan et al. (2025), this study investigates the relationship between ICER and ten candidate genes (gdf6a, pdgfra, col4a4, fgfr2, pdgfrb, cdkn1a, fgf5, akt1, met, and notch3) associated with BMP signaling. Quantitative polymerase chain reaction (qPCR) was used to compare gene expression between …

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 …

An Analysis Of Mating Strategies In Rotifers Inhabiting Temporary Habitats, Ariel Bollinger

Open Access Theses & Dissertations

Reproduction is critical for organisms inhabiting ephemeral aquatic habitats where desiccation risk favors rapid and successful mating. Monogonont rotifers rely on sexual reproduction to produce diapausing eggs that withstand harsh conditions. I investigated how mating behaviors vary among populations of five rotifer species based on the hydroperiod of their habitat: Epiphanes brachionus and E. chihuahuaensis were sampled from habitats with short (SH) and long (LH) hydroperiods; Euchlanis dilatata was collected from a short (SH) and a permanent habitat; and Plationus patulus and Sinantherina socialis were collected from a long (LH) and a permanent (Perm) habitat. I hypothesized that SH populations …

Parametric Assessment Of Nicotine Vapor Self-Administration In Rats, Tiffany Alexandra Gonzalez-Gutierrez

Open Access Theses & Dissertations

The increasing prevalence of electronic cigarette (e-cigarette) use among adolescents highlights the need to identify factors that promote nicotine vapor use in populations most susceptible to its long-term consequences. This requires translationally relevant animal models of nicotine vapor self-administration (VSA). Accordingly, the goal of this dissertation was to evaluate 2 key factors hypothesized to influence nicotine VSA in rats, including age and e-liquid vehicle composition. Given recent mandates on studying sex as a biological variable, the present work included both female and male rats. Aim 1 compared VSA behavior during adolescence (adolescent-onset) or adulthood (adult-onset) in groups that received vapor …

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 …

Extinction Risk Of Coral Reef Fishes In The Philippine Marine Ornamental Trade, Jemelyn Grace Baldisimo Sepulveda

Biological Sciences Theses & Dissertations

Coral reef ecosystems in the Philippines face severe threats from intense fishing and habitat degradation. This dissertation evaluated the extinction risk of fishes in the Philippine Marine Aquarium Trade (MAT) using Productivity Susceptibility Analysis (PSA) and temporal genomics. A global PSA framework was modified by including local susceptibility factors. Of the 103 species evaluated, six were categorized as highly vulnerable and 62 as moderately vulnerable, revealing increased local vulnerability and underscoring the importance of local assessments to guide conservation efforts.

Temporal genomics compared historical (1908–1909 U.S.S. Albatross Expedition) and contemporary populations of the MAT-targeted Sphaeramia nematoptera and Pseudanthias squamipinnis, …

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. …

Building Bridges: Connecting Biomechanics And Lived Experience In Bertolotti's Syndrome, Andrea Morgan Muffly

Rehabilitation Sciences Theses & Dissertations

Bertolotti’s Syndrome (BSy), characterized by the presence of a lumbosacral transitional vertebra (LSTV), represents a complex clinical entity that affects not only the physical health of the individual, but the quality of their daily life. Prior research on BSy focused on epidemiology, not lived experience, revealing inconsistencies in diagnostic inconsistencies of LSTV morphology. A three-tiered diagnostic system is proposed to streamline the reporting of LSTV subtypes. We examined how BSy is diagnosed, its symptoms, presentation, and how this impacts individuals’ ability to participate in activities of daily living (ADLs) and instrumental activities of daily living (IADLs). We conducted a multi …

From Shallow To Upper Mesophotic Reefs: Examining Environmental Influences On Coral Physiology And Thermal Tolerance, Katherine Eileen Parker

Biological Sciences Theses & Dissertations

Coral reefs are increasingly threatened by rising ocean temperatures, yet coral thermal tolerance varies widely across species, populations, and environments. This dissertation investigates the biological and environmental mechanisms underlying coral thermal resilience, with a focus on symbiosis dynamics, photoacclimation, and the interaction between light and heat stress across environmental gradients. Specifically, it examines how coral-Symbiodiniaceae partnerships respond to thermal stress using the Coral Bleaching Automated Stress System (CBASS) across contrasting thermal and light environments, spanning population-level differences, depth-associated variation, and experimental manipulation of light during acute heat stress. First, thermal thresholds and transcriptomic dynamics were examined in two wild Porites …

The Impact Of Hypoxia And Androgen Inhibition On Prostate Cancer Cell Dedifferentiation And The Dna Damage Repair Response At Telomeres, Arooba Ayaz

Biomedical Sciences Theses & Dissertations

Long-term Androgen deprivation therapy (ADT) is used to treat Prostate cancer (PCa) but is often met with resistance & the development of Neuroendocrine (NE) PCa which is rarer but more aggressive. Antiandrogens are a part of ADT that work to inhibit androgen receptor in PCa cells. In vitro, PCa cells under long-term antiandrogen treatment become NE-like and adopt stem-like characteristics. The disruption of androgen signaling though the use of antiandrogens impacts many cellular processes that play a major role in cancer cell proliferation such as the DNA damage repair response (DDR) and telomere dysfunction. In vivo, PCa tumors have disorganized …

Modulation Of Electrophysiology And Plaque Aggregation In Huntington’S Disease Patient-Derived Cells By Picosecond Pulsed Electric Fields, Mackenzie A. Tardif-Kunk

Biomedical Sciences Theses & Dissertations

Huntington’s Disease (HD) is a fatal, autosomal dominant neurodegenerative disorder characterized by progressive motor and cognitive decline. Unstable expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the huntingtin gene, often exceeding 35–40 repeats, results in an extended polyglutamine (PolyQ) tract in the translated protein. Abnormal folding of the mutant huntingtin (mHTT) protein leads to accumulation and aggregation within the cell, dysregulating various cellular processes through molecular sequestration. While several therapeutic strategies have been proposed, this disease remains incurable with treatments limited to symptom management.

Pulsed electric fields (PEF), primarily in the microsecond and nanosecond ranges, have been studied extensively for the …

Mechanism Of Hypothiocyanous Acid Reductase, Morgan L. Fowler

Masters Theses

Hypothiocyanous acid reductase (Har) is a flavin-dependent enzyme that is effective in protecting bacteria from hypothiocyanous acid. HOSCN is an antimicrobial oxidant that is excreted by the mammalian innate immune system during inflammation, targeting and attacking thiols in pathogens. To combat HOSCN, bacteria have developed defense systems, including hypothiocyanous acid reductase. The catalytic mechanism by which Har interacts with its substrates, HOSCN and NADH, is undetermined and requires exploration.

In this study, we characterized the reductive and oxidative half-reactions of E. coli Har (EcHar). We first investigated and characterized wild-type EcHar, showing that Har is extremely efficient in reacting with …

Secondary Biology Teachers’ Understandings Of Growth Mindset, Kathryn Chapman

Dissertations

This case study investigates how high school biology teachers understand and apply growth mindset principles in their daily instruction. Using surveys, semi‑structured interviews, and focus groups, the study examines how biology teachers interpret mindset, how they attempt to enact it, and how curriculum demands shape their efforts. Findings show that teachers’ beliefs about intelligence strongly influence their feedback, expectations, and instructional decisions. Teachers described biology as a subject in which struggle is highly visible, emotionally charged, and often tied to students’ prior knowledge, making mindset work both necessary and challenging. Results also indicate that students’ mindsets are shaped by broader …

Expression Levels Of Heat Shock Protein 72 And Their Correlation With Biomarkers Of Renal Function Among Hispanic Construction Workers Exposed To Ambient Heat In El Paso, Texas, Maria Fuentes

Open Access Theses & Dissertations

Heat shock proteins (HSP) are intracellular molecular proteins that are upregulated in response to cellular stress, including heat exposure. Through their protective functions, HSP help maintain protein structure, prevent protein denaturation, and preserve cellular homeostasis during states of physiological stress. Because of their cytoprotective properties, HSP have emerged as potential biomarkers for detecting early signs of tissue injury and predicting clinical outcomes associated with heat related illnesses (HRI), including acute kidney injuries (AKI). AKI is a leading cause of hospitalizations due to heat stress exposure and heat stroke. In the absence of early detection and effective therapeutic interventions, AKI may …

The Rpm-1/Phr Signaling Hub Modulates Tau-Induced Neurodegeneration Through Regulation Of Microtubule Stability And Mapk Pathways In C. Elegans, Xinxing Ding

Theses and Dissertations

Neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia, are characterized by the accumulation of pathological tau proteins and progressive neuronal loss. Although research regarding tau-mediated toxicity is extensive, the specific pathology that determine whether neurons maintain homeostasis or succumb to collapse under tau-induced stress remain incompletely elucidated. A central, yet still insufficiently understood, feature of these diseases is the disruption of the microtubule (MT) cytoskeleton . The PHR protein family is evolutionarily highly conserved; within this family, RPM-1 in C. elegans functions as an intracellular signaling hub that regulates axon development, synapse formation, axon termination, and various microtubule-associated processes. This …

Betwixt Two Dams: Persistence And Angler Use Of Two Trout Taxa In A Western Nebraska Tailwater Fishery, Lauren R. Allex

Biology Theses, Dissertations, and Student Creative Activity

Stocking catchable-sized trout is a widely used management strategy to create and maintain recreational fisheries. However, the success of these programs relies on if the fish is caught and how long the fish remain available to anglers. Lake Ogallala is a dynamic tailwater cool-water reservoir that has been managed as a salmonid fishery since 1941 where Nebraska Game and Parks Commission (NGPC) has stocked 8 different salmonids to maintain a recreational fishery. Currently, NGPC is stocking Rainbow Trout Oncorhynchus mykiss and Cutbow Trout Oncorhynchus mykiss x clarkii.

In order to understand the angler dynamics of this fishery, creel surveys collected …

Identify And Widen Bottlenecks In The Asexual Restoration Of Endangered Orbicella Faveolata Boulder Coral, Whitney Schwab

All HCAS Student Capstones, Theses, and Dissertations

Landscape-scale coral reef restoration is constrained by the context-dependent responses of corals to environmental and ecological conditions throughout a region, and identifying factors affecting the growth and survival of key reef-building species is essential for maximizing restoration success. In collaboration with Nova Southeastern University (NSU), the University of Miami (UM), and Mote Marine Laboratory, this study evaluated the relative effects of intrinsic factors (putative genotype and source colony location) and extrinsic factors (ex-situ nursery system characteristics, in-situ nursery location, nursery type (ex-situ vs. in-situ), and environmental conditions) on Orbicella faveolata tissue regeneration and survival following fragmentation. Corals …

Microplastic Effect On Behavior Of Nudibranch (Berghia Stephanieae); A Trophic Transfer Study, Isabela Salina Fernandes Beneli

Electronic Theses and Dissertations 2020 - Present

With the continuous rise in economic supply and demand, an enormous increase in waste, litter, and pollution has been seen globally, with plastic pollution being the most abundant category. Microplastic (< 5 mm), derived from larger plastics, pollution is intensely widespread across marine ecosystems and can be transferred across trophic levels through predator-prey interactions. Recent studies have shown that ingestion of MPs can damage cells, tissues, and internal organs and increases oxidative stress leading to malformations, reduced feeding and growth, , and slower developmental rates in a wide array of organisms. This study examined the trophic transfer of microplastics (MPs) from the anemone Exaiptasia pallida to its specialist predator Berghia stephanieae, and evaluated the effects of exposure on predator behavior. A dose-response experiment demonstrated that MP retention in E. pallida decreased over time, although higher exposure concentrations resulted in greater initial microplastic concentrations. Trophic transfer to B. stephanieae was confirmed through feeding experiments. Behavioral assays revealed that B. stephanieae did not exhibit a preference between MP-exposed and control prey. However, microplastic …