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Exploring Hybrid Cohort-Based Doctoral Program Features That Support Nontraditional Doctoral Students’ Persistence: A Preregistered Case Study., Glenda Winborn

Graduate Theses and Dissertations

With the rise of hybrid learning models, non-traditional learners have greater access to doctoral education. However, attrition rates from doctoral programs remain high, ranging from 40% to 50% across all doctoral programs and exceeding these levels in online non-traditional programs. Numerous causes of attrition or persistence in doctoral studies have been researched and can affect the student, the academic institution, and the broader academic society. This qualitative case study will explore adult and lifelong learning doctoral students' perceptions of the programmatic and instructional support resources that have helped improve persistence in their program. Two of the important programmatic features of …

Effects Of Cholesterol Concentration On Liposome And Proteoliposome Behavior, Ehsaneh Khodadadi

Graduate Theses and Dissertations

Cholesterol is crucial in modulating the behavior and characteristics of biological membranes, liposomes, and proteoliposomes, for instance in drug delivery applications. Cholesterol regulates membrane stability by influencing lipid density, phase separation, and protein-membrane interactions. In planar bilayers, cholesterol enhances membrane thickness, reduces permeability, and promotes lipid ordering, adding rigidity and fluidity. Cholesterol also modulates membrane curvature in curved bilayers and vesicles, stabilizing low-curvature regions. In this work, all-atom molecular dynamics (MD) simulations were employed to examine how varying cholesterol concentrations influence the structure and dynamics of membranes, focusing on planar and curved geometries. Bilayers with cholesterol molar ratios of 0%, …

Bang!: Real-Time Measurements And Transcriptomics Of Metabolic Reprogramming In Activated Macrophages At Fever Temperature, Kenneth Howard Taylor

Graduate Theses and Dissertations

We investigated the real-time metabolic rates of activated macrophage cell lines derived from mouse, chicken and rainbow trout. Each species showed a different kinetic signature with metabolic rates accelerating under fever conditions specific to each organism. Upon activation mouse macrophages increased their rate of glycolysis early and then a later reprogramming phase occurred with a dramatic decrease in oxidative phosphorylation (OXPHOS) accompanied by a reciprocal second increase in glycolytic rates. Chicken macrophages showed an initial increase in both glycolytic and OXPHOS rates. The late drop OXPHOS rates also occurred in chicken however there was no reprogramming that occurred as glycolytic …

Male And Female Contributions To Sexual Dimorphism, Catherine L.W. Clayton

Graduate Theses and Dissertations

Since Darwin, the evolution of sexual dimorphism connects to different evolutionary mechanisms reflecting both natural selection and sexual selection. In primates, body size dimorphism has been attributed to multiple factors, including sexual selection, fecundity selection, ecological selection, and other factors. In contrast, canine tooth size dimorphism has been primarily associated with sexual selection in males with minor change in females, with other factors playing only a secondary role. This suggests that the degree to which body size dimorphism and canine size dimorphism covary, controlling for phylogeny, should reflect the strength of sexual selection. Conversely, the magnitude of divergence between the …

Fixed-Time Artificial Insemination Protocols Using Pre-Synchronization In Suckled Beef Cows, Wyatt Eugene Weber

Graduate Theses and Dissertations

Adoption of artificial insemination by beef producers has been limited within the United States. Estrous synchronization (ES) for fixed-time artificial insemination (FTAI) has been one of the most effective ways to implement artificial insemination into beef production systems, but its efficiency has primarily been restrained by the dependency on the effectiveness of the initial gonadotropin releasing hormone (GnRH) injection in many FTAI protocols. The hypotheses of these studies were to determine practical methods of pre-synchronization to improve current FTAI protocols, ultimately increasing beef herd reproductive performance. The objective was to evaluate the use of prostaglandin F2α (PGF) and progesterone (P4) …

An Analysis Of Cellular And Tissue Function Of Lipin In Drosophila Melanogaster, Judah Christian Scott

Graduate Theses and Dissertations

Regulation of energy expenditure and energy storage is a key characteristic of life. Numerous enzymes play a crucial role in regulating energy metabolism. Lipins are a highly conserved family of proteins that function in both lipid synthesis and gene regulation. In the glycerol-3 phosphate pathway, lipins act as a phosphatidate phosphatase (PAP) producing diacylglycerol. In gene regulation, lipins act as transcriptional co-regulators of metabolic genes. The enzymatic PAP activity occurs in the cytoplasm; however, for lipins to function as gene regulators, they must translocate into the nucleus. Nuclear translocation is facilitated by the nuclear localization signal (NLS) within the protein. …

Functional Consequences Of Lysine Acetylation Of Phosphofructokinase Isozymes, Xinyu Lin, Nour Fatema, Qinglei Gan, Chenguang Fan

Chemistry & Biochemistry Faculty Publications and Presentations

Phosphofructokinase (Pfk) catalyzes the phosphorylation of fructose 6-phosphate and is a key regulatory point in the glycolysis pathway. Multiple lysine residues in both Pfk isozymes, PfkA and PfkB, have been identified to be acetylated in Escherichia coli by proteomic studies, but no studies have been implemented to further characterize these acetylation events. To investigate the role of Pfk acetylation, the genetic code expansion strategy was used to generate homogeneously acetylated Pfk variants at target lysine sites that have been reported to be acetylated in nature. We found that acetylation of K309 of PfkA and K27 of PfkB decreased PfK enzyme …

Development Of Soil Water Characteristic Curves Through Control Of Relative Humidity, Lauren E. Johnson, Julia I. Loshelder, Richard A. Coffman

Civil Engineering Undergraduate Honors Theses

The relationship between soil suction and soil water content in unsaturated soil mechanics is important but can be difficult to measure. The objective of the research described herein was to develop soil water characteristic curves (SWCC) from relative humidity values by incorporating the use of glycerin-water mixtures. Glycerin-water mixtures can be used to achieve different relative humidity levels by varying the concentration of glycerin within the mixture. The relative humidity created by each mixture was measured with a relative humidity sensor, and the relative humidity values and Kelvin’s equation were used to compute the total suction.

Soil water characteristic curves …

Empowering Through Technology: An Internship Report On Augmentative And Alternative Communication Devices, Olivia G. Macdonald

Communication Disorders and Occupational Therapy Undergraduate Honors Theses

Augmentative and Alternative Communication (AAC) devices play a crucial role in supporting individuals with communication challenges, particularly children with developmental disabilities such as Autism Spectrum Disorder (ASD). This paper provides a comprehensive review of the literature on AAC and offers a detailed report of an internship experience at the University of Arkansas WE CARE Summer Camp. During the internship, firsthand experiences provided valuable insights into how AAC technologies can be applied to enhance communication, foster social connections, and support behavioral regulation.

The literature review explores the different types of AAC systems, including both aided and unaided options, and discusses the …

Preclinical Development Of Genome Editing To Treat Duchenne Muscular Dystrophy By Exon Skipping, Made Harumi Padmaswari, Shilpi Agrawal, Christopher E. Nelson

Biomedical Engineering Faculty Publications and Presentations

Duchenne muscular dystrophy (DMD) is caused by loss-of-function mutations to the gene encoding dystrophin. Restoring the reading frame of dystrophin by removing internal out-of-frame exons may address symptoms of DMD. Therefore, the principle of exon skipping has been at the center stage in drug development for Duchenne muscular dystrophy (DMD) over the past two decades. Antisense oligonucleotides (AONs) have proven effective in modulating splicing sites for exon skipping, resulting in the FDA approval of several drugs using this technique in recent years. However, due to the temporary nature of AON, researchers are actively exploring genome editing as a potential long-term, …

Geospatial Modeling Of Winter-Related Property Damage In Arkansas, Braedyn Mcbroom

Graduate Theses and Dissertations

Storm Data, a monthly publication by the National Weather Service with records of weather events, reports on property damage caused by natural hazards. Since 1996, the database has included winter-related events. While the property damage data is considered incomplete, no other unique, public datasets report winter-related property damage at the county level. From 1996 to 2024, Arkansas ranked #1 in winter-related property damage. To understand the factors that are driving property damage and potentially reduce Arkansas’ vulnerability to it, three groups separated by temporal periods, i.e., “2000” (01/1996 - 06/2005), “2010” (07/2005 - 06/2015), and “2020” (07/2015 - 06/2024) …

Conservation Agriculture Practice Effects On Greenhouse Gas Emissions From Fine-Textured Soils In Arkansas, Lauren Gwaltney

Graduate Theses and Dissertations

Biochar application and reduced tillage (RT) are both practices within the conservation agriculture framework, but specific impacts of these practices on direct greenhouse gas (GHG) emissions still require investigation in varied agricultural systems. This research aimed to evaluate the effects of biochar source (i.e., powder- and pellet-sized) and application rate (i.e., 0, 2.5, and 5 Mg ha^-1) on GHG production in simulated furrow-irrigated rice (Oryza sativa) in a greenhouse experiment, and to evaluate the effects of RT relative to conventional tillage (CT) on GHG production in soybean (Glycine max) in southeast Arkansas. Both studies …

Gene Expression And Transfection Of C15orf57 In Chicken Show Clear Correlation To The Function Of The Ap2 Complex, E. Ashton Magdich

Graduate Theses and Dissertations

Discovering the functions of functionally unknown genes has made a huge impact on biological understanding including poultry species. In this thesis, C15orf57 (or C5H15orf57, chicken chromosome 5 human ortholog H15 open reading frame 57), was studied to understand its genetic characteristics and function. Chapter one is literature reviews on annotation of genes, the gene information on C15orf57, the importance of characterizing unknown genes in the genome, and what is known now about C15orf57. The Chapter 2 is for the structural characterization of C15orf57, gene expression of C15orf57 in various organ tissues using the qPCR method and effect of overexpression of …

Bacterial Chondronecrosis With Osteomyelitis In Broilers: Etiology And Selected Mitigation Measures, Khawla Saud Alharbi

Graduate Theses and Dissertations

Bacterial chondronecrosis with osteomyelitis (BCO) is the predominant cause of lameness in broiler chickens. It mainly impacts broiler production and animal welfare, causing substantial financial losses accounting for 1- 2% due to bird condemnations at the marketing age. Remediating BCO lameness disease demands investigating its causes using appropriate models and evaluating preventive measures, such as enhancing epithelial tissue health and tight junction integrity in the digestive and respiratory tract, strengthening immune functions, and improving bone strength. Therefore, the objectives of this dissertation were to 1) study predisposing factors for BCO lameness by investigating the effects of deoxynivalenol (DON) and fumonisin …

Exploring The Relationship Between Novice Teacher Autonomy And Workplace Engagement, Burnout, And Intentions To Remain In The Teaching Profession, Bryce Bennett

Graduate Theses and Dissertations

Administrators and experienced faculty frequently disagree on the degree of autonomy that should exist for classroom teachers. Administrators seeking to make adjustments to the levels of autonomy experienced by their teachers may struggle to account for differences between novice teachers and their more seasoned counterparts. This study applies researched-based models for exploring the relationship between various job resources and demands and their ultimate impact on workers. A mixed method designed employing a survey across three large school districts in Arkansas asked participants questions intended to uncover the degree of autonomy novice teachers typically experience, levels of burnout & workplace engagement, …

Evaluating The Impact Of Work-Based Learning On Postsecondary Completion And Job Placement Of Electronics Technology Students, Amanda J. Seidenzahl

Graduate Theses and Dissertations

The manufacturing industry today is facing a critical shortage in the availability of talent and skills needed in an ever-changing technological workforce. With an estimated 2.1 million jobs in the manufacturing industry predicted to be unfilled by 2030, organizations are struggling to find a workforce with the skills needed for this evolving industry (NAM, 2020; Ahmad, 2019). Employers have often suggested there is a lack of alignment between classroom experience in higher education, and work-based learning (WBL) is one option to bridge this gap (Krishnamoorthy & Keating, 2021). WBL provides real world experiences that connect learning in the classroom (Krishnamoorthy …

Leveraging Natural Variation In Yeast To Understand Susceptibility Differences In Parkinson’S Disease, Julio Andres Molina Pineda

Graduate Theses and Dissertations

Parkinson’s Disease (PD) is a neurodegenerative disorder that causes countless suffering around the world. Both forms, familial and sporadic, have been associated with the misfolding and cytotoxicity of α-synuclein, an otherwise non-pathogenic protein suspected to have various roles in the normal maintenance of the central nervous system. Model organisms have emerged as great vessels to uncover the cellular and molecular mechanisms that shape α-syn biology, and great strides have been made to understand it. Yet, it is still unclear why some individuals are affected by α-syn toxicity, while others not so much. Since it’s extremely complicated to study and probe …

The Evolving Changes In The Regionalization Of Export Bans On U.S. Poultry Trade From The 2015 And 2022 Highly Pathogenic Avian Influenza Events, Kylie A. Roesler

Graduate Theses and Dissertations

As food security becomes a growing concern worldwide in a trading system dominated by globalization, the safeguarding of a bio-secure food system is at risk. One of the greatest risks to this stability of the system is, highly pathogenic avian influenza or HPAI which is growing in frequency and impact. Therefore, the global response to disease events is evolving into a newfound understanding of disease prevalence across the animal protein industries. This study will analyze the 2022 HPAI event in the United States regarding the regionalization of restrictions imposed by trading partners accounting for trade agreements executed. The examination of …

Evolutionarily Conserved Functions Of The Gene Frazzled In Midline Axon Guidance In Drosophila Melanogaster And Tribolium Castaneum., Piyasi Ghosh

Graduate Theses and Dissertations

Axon guidance in bilaterians is often controlled by various signaling pathways in the nervous system, which determine the fate of the axons if they cross the midline or not. One such pathway involved is the ligand-receptor pair Netrin (Net) and Frazzled (Fra), which is also known as the attractive pathway that promotes midline crossing axons in insects and other bilaterians. Orthologs of the pathway ligand Netrins and their receptors Frazzled [Fra] in insects and Deleted in Colorectal cancer [DCC] in vertebrates are widely conserved in bilaterians. How well these regulatory roles of the protein are conserved is poorly understood. In …

Sibling Groups And Family Adaptability And Cohesion Among Emerging Adult Women, Julianne M. Post

Graduate Theses and Dissertations

This study examined how sibling group size is related to family adaptability, cohesion, and individual resiliency outcomes during emerging adulthood. Using Bowen's Family Systems Theory and Olson's Circumplex Model, the research investigates sibling subsystems as sites where systemic imbalances are first experienced within families. Data from 124 college students revealed that larger sibling groups were associated with marginally higher disengagement and chaos resulting in decreased perceived social support, suggesting resiliency implications for youth growing up within larger families. While sibling size didn't directly predict mental health, family dynamics significantly mediated the relationship between sibling composition and resiliency outcomes. Demographic factors …

Bacterial Chondronecrosis With Osteomyelitis In Broiler Chickens: Experimental Lameness And Additive Probiotic Treatments, Amanda Anthney

Graduate Theses and Dissertations

With the global population already surpassing 8.2 billion and expected to reach 9.7 billion by 2050, the poultry industry has seen a surge in demand due to its unmatched efficiency and affordability for consumers across the globe. Selective breeding and quality nutrition developments since the industry's commercialization have allowed producers to grow broilers up to 7 pounds by market age. While this extraordinarily efficient process has allowed quality poultry products to be available worldwide, the modern-day broiler has developed a multitude of musculoskeletal issues. Due to the lack of integral skeletal development to match the rapid production of muscle tissue, …

Characterization Of Streptococcus Gallolyticus: An Emerging Pathogen Causing Turkey Streptococcosis, Latasha S. Gray

Graduate Theses and Dissertations

During the past five years, there has been an increased occurrence of Streptococcus gallolyticus in young turkey poults. This emerging pathogen previously affected turkey flocks without any indication of disease prior to acute mortality. However, recently there has been two cases of neurological presentation associated with S. gallolyticus subsp. pasteurianus that are unique to traditional disease presentation in turkey poults. The objectives of the present dissertation were to compile data associated with the two neurological cases and compare different S. gallolyticus strains as well as pathogenic Enterococcus cecorum to the neurological strains. The two neurological cases occurred between July and …

Application Of Ordinal Regression Models To Acquired Stress Resistance In Wild Strains Of Saccharomyces Cerevisiae, Carson Stacy

Graduate Theses and Dissertations

This thesis explores the application of ordinal regression to the analysis of semi-quantitative growth assays often used when comparing fitness for different strains of the model yeast Saccharomyces cerevisiae. For stress survival assays, yeast stress resistance is measured using an ordered survival score that ranges from 0 (no growth) to 4 (confluent growth). Traditional approaches to analyze this type of data either treats data as a nominal categorical variable or as a continuous numerical variable. These approaches risk loss of information or violation of testing assumptions. In contrast, cumulative logit ordinal regression uses the information contained in the order …

Physiological And Molecular Responses Of Diverse Rice Genotypes Under Drought Stress, Huda Mohmmed Alshaya

Graduate Theses and Dissertations

Climate change-induced drought stress is a significant constraint on global rice (Oryza sativa L.) production, threatening food security. This study evaluated the drought resilience of 15 diverse rice genotypes from the USDA mini-core collection under field, greenhouse, and osmotic stress conditions. Field trials assessed reproductive-stage drought tolerance based on panicle length (PL), number of spikelets per panicle (NSP), and spikelet sterility (SS). Greenhouse experiments examined moisture retention at the vegetative stage. Significant genotypic variation was observed, with genotypes 310724, 310779, 311181, 311603, 311793, and Vandana exhibiting drought tolerance through stable PL and SS. Additionally, genotypes 310100, 310428, 311255, N22, …

Variation In Stress Response Regulation Across Natural Isolates Of Saccharomyces Cerevisiae, Crystal Christine Crook

Graduate Theses and Dissertations

The stress response of Saccharomyces cerevisiae is a valuable area of study for understanding cellular adaptation mechanisms that govern survival in fluctuating environments. This dissertation investigates stress response regulation in yeast through the roles of Hog1 mitogen-activated protein kinase (MAPK) and the post-transcriptional regulator Mkt1, a key post-transcriptional regulator, in diverse wild yeast isolates. Hog1 is traditionally known for its central role in osmotic stress regulation in the high-osmolarity glycerol (HOG) pathway. This study expands the functional scope of Hog1 to include oxidative and ethanol-induced stress responses.

In parallel, we investigate post-transcriptional regulation of stress responses by the Mkt1 interactome, …

Elucidating The Mechanisms Of Collagenase H From Hathewaya (Clostridium) Histolytica In Collagen Degradation And Developing A Cross-Linked Platform For Efficient Capture And Release Of Adeno-Associated Virus Serotype 2 (Aav2), Adjoa Otubea Bonsu

Graduate Theses and Dissertations

In biological systems, Hathewaya (Clostridium) histolytica secretes collagenases that degrade structural collagen in host tissues and cause tissue necrosis. Despite their detrimental effects, these enzymes have significant therapeutic potential by effectively digesting various collagen subtypes to treat connective tissue disorders. The bacterium produces two homologous collagenases, ColG and ColH, with a catalytic module crucial for hydrolyzing collagen and binding domains, including collagen-binding domains (CBDs) and polycystic kidney disease-like domains (PKDs), for substrate interaction.

Although the crystal structure of the catalytic module of collagenase G (ColG) has been determined, shedding light on its chew-and-digest mechanism, the structure of collagenase H (ColH) …

Critical Analysis Of Coursework And Internship Experience In Relation To Biological Engineering At The University Of Arkansas, Samantha Wheat

Biological and Agricultural Engineering Undergraduate Honors Theses

My internship allowed me to gain important experience about a possible future career path with a biological engineering degree. Not only did this experience apply knowledge learned in the classroom from classes taken, I was also able to use my critical thinking skills gained from biological engineering coursework and teaching style to learn new skills and efficiently complete tasks given to me. This internship allowed me to try out a possible career path that interested me, and through my internship experience I was able to learn more about what kind of career path I was interested in after graduation. Additionally, …

Effects Of Sensor Separation On Flux Calculations In The Eddy Covariance Method., Maria D. Vergara Murillo

Biological and Agricultural Engineering Undergraduate Honors Theses

Rice production contributes approximately 8% of global anthropogenic methane emissions. Methane (CH₄) is a powerful greenhouse gas with a global warming potential 28 times greater than carbon dioxide (CO₂) which makes it important to monitor for understanding and mitigating its contribution to climate change. The Eddy Covariance (EC) method is used to monitor greenhouse gas emissions such as CO₂, CH₄, etc. As part of the EC method, the instruments on the EC towers are used to record the gas concentrations in the atmosphere; these concentrations are then run in the EddyPro software …

Understanding The Impact Of Fall Armyworm (Spodoptera Frugiperda) Feeding, And Drought Stress On Drought-Tolerant And Drought-Resistant Soybean (Glycine Max)., Adriana G. Peissel

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Drought and insect herbivory are two major stressors on high-value crops like soybean (Glycine max). However, few studies have explored how these stressors interact, despite their presence in tandem under field conditions. We investigated how drought stress and fall armyworm (Spodoptera frugiperda) caterpillar herbivory impact Magellan (drought-tolerant) and Blackhawk (drought-susceptible) soybean cultivars. The soybean plants were subject to four treatment groups (1. Drought 2. Herbivory 3. Drought + Herbivory 4. Well-Watered) during a treatment period of 7 days in a greenhouse. We then measured plant height, physiological traits, trichome density, soil moisture, and larval mass gain. …

Understanding Factors That Drive Wildlife Mortality During Prescribed Fire Management Of Prairie Restorations, Hunter M. Griffey

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Fire is a key ecological disturbance, which plays a vital role in maintaining biodiversity and early successional species. For today’s land managers, prescribed fire is key in the restoration and maintenance of prairie ecosystems, halting woody encroachment and creating habitat desperately needed by many species. However, fire may have unintended effects on wildlife populations through direct mortality. Among taxa living in fire-dependent ecosystems, reptiles are predisposed to direct mortality, and several studies have recorded significant mortality during prescribed burns. However, the few studies investigating reptile mortality in prescribed fire are limited by small sample sizes and generally have limited analysis …