Digital Commons Network^™

Cell-Type Specific Control Of Visual Fixation In Drosophila Melanogaster, Meagan Leung

Biological Sciences

Navigation in complex environments requires precise visual processing. To move effectively through their surroundings, animals must orient toward and maintain fixation on objects of interest to preserve a stable heading. However, the neural mechanisms underlying this behavior remain poorly understood. We use Drosophila melanogaster as our model organism because its visual behavior can be precisely measured and the availability of genetic tools which enables us to perturb the underlying neural circuits. Using a closed-loop virtual reality environment combined with locomotion tracking, we developed a stimulus protocol that reliably elicits fixation responses. To determine whether specific visual neurons drive fixation responses, …

Long-Term Stimulant Use Is Associated With Normalized White Matter Integrity In The Vta-Nacc Pathway In Adolescents, Isaac T. Arsenault

Biological Sciences Undergraduate Honors Theses

Medical practitioners are diagnosing Attention-Deficit/Hyperactivity Disorder (ADHD) at a high and ever-increasing rate. The use of stimulant medication to treat ADHD is also increasing and is associated with changes in the brain. Past research found that children with ADHD have lower volume in reward neurocircuitry, such as the ventral tegmental area (VTA) and the nucleus accumbens (NAcc). Research has also found that stimulant usage in those with ADHD might “normalize” the reward circuits. However, few longitudinal studies have directly tested the long-term effects of stimulant medication on brain development. Here we tested whether long-term stimulant use is associated with changes …

The Impact Of High-Cadence Cycling On Overground Running Performance In Recreational Runners, Matthew Ott

Master's Theses

Cycling is a commonly used exercise because it provides a controllable cardiovascular and musculoskeletal demand while imposing relatively low impact on the rider. High-cadence cycling (HCC) has been shown to influence subsequent running performance and gait performance by increasing cadence and reducing work rate when cycling prior to running. However, most of this work has focused on triathletes and older adults. Therefore, the purpose of this study was to examine the acute effects of HCC on subsequent 800 m running performance and spatiotemporal parameters in adult recreational runners. Thirty recreational runners completed two testing sessions. On Day 1, participants performed …

Lumbopelvic Kinematics And Muscular Co-Contractions In Walking Prior To And Immediately Following A Bout Of Prolonged Standing., Stephanie Cotariu

Graduate Theses and Dissertations

Background: Prolonged standing is a common daily activity in a wide array of occupations, and approximately 44% of sample populations develop low back pain (LBP) during prolonged standing. Prolonged standing-induced LBP developers (“Pain Developers”) are three times more likely to develop clinical LBP and can therefore be considered a pre-clinical LBP population. Changes in typical gait have been observed in LBP patients, and walking has been hypothesized as being protective or preventive against LBP development. However, it is unknown whether Pain Developers exhibit similar kinematic adaptations to chronic LBP patients during common daily activities, such as walking. The exact muscular …

Dfend: A Nutrition Education Intervention To Improve Food Budgeting, Shopping, And Meal Preparation Skills Among Adults In Arkansas, Samantha K. Edwards

Human Nutrition and Hospitality Management Undergraduate Honors Theses

Preventive strategies targeting modifiable lifestyle factors related to food, nutrition, and health are needed as chronic health conditions continue to rise. Nutrition literacy refers to having the knowledge and skills needed to obtain, understand, and apply nutrition information to make informed dietary decisions. Without adequate nutrition education and food security, vulnerable populations are at risk of malnutrition and poor dietary behaviors. Educational interventions that increase food literacy can help improve dietary choices and food selection skills.

The purpose of this creative project was to develop a nutrition education toolkit for Extension agents to implement among rural populations with low health …

Structural Evidence For Innervation Of A Single Epitheliomuscular Cell By Multiple Sensory Neurons In The Sea Anemone Nematostella Vectensis, Aparajita Das

Graduate Theses and Dissertations

Abstract Here, I report new ultrastructural evidence for multineuronal innervation (many-one) of a single epithelia-muscular cell in sea-anemone cnidarian Nematostella vectensis. Using Serial Block-Face Scanning Electron Microscopy (SBF-SEM) and ImageJ, I found that EMCs are located at the base of ectoderm, with an elongated cell body that includes basal processes, a bilobed nucleus, and myofibrils aligned parallel to the basal surface along with their structural quantification. Notably, I found multiple mechanosensory neurons form synapses with a single EMC. These findings enhance our understanding of cnidarian neuromuscular organization and reveal that coordination between sensory and contractile systems in N. vectensis is …

Leveraging Historic Collections: Investigating Morphometric Differentiation In Members Of The Arisaema Triphyllum (L.) Schott (Araceae) Species Complex, Morgan Bradley Russell

Graduate Theses and Dissertations

The Jack-in-the-pulpit (Arisaema triphyllum (L.) Schott) is an herbaceous perennial herb of North America, and its taxonomic history is full of confusion and rank shifts. Now split into six species, the A. triphyllum species complex consists of morphologically similar taxa that have differing ploidy levels. In Chapter I, I compiled a detailed introduction and history for these taxa, focusing on their taxonomic complexity and morphological ambiguity in herbarium specimens and immature plants. I also presented their ploidy distinctions and how the implications of polyploidy may hold answers to parsing them apart, especially in dried herbarium specimens where defining characteristics are …

Impact Of Salt Block Utilization During Dry-Aging On Pork Loin Microbial And Meat Quality, Cason H. Frisby

Food Science Undergraduate Honors Theses

This study aimed to investigate the effects of dry-aging and salt block utilization during dry aging on pork loin quality attributes. Pork loins were collected at 7 days postmortem, cut into three equal sections, and randomly assigned to wet aging (WA), traditional dry-aging (DA), and salt block dry-aging (SDA) groups to be aged for 28 days. During the dry-aging period, SDA cabinet exhibited lower humidity fluctuation (Avg. 71.52, St. Dev. 4.7) compared to DA cabinet (Avg 70.76, St. Dev. 7.9). Following the aging period, no differences were found in pH or Warner Bratzler shear force values between treatments (P>0.05). …

Precision To Protein: Comparative Characterization Of Printability, Physicochemical, And Nutritional Properties Of Cricket, Pea, And Whey Proteins In 3d-Printed Nutrition Bars, Sophia Hinkebein

Food Science Undergraduate Honors Theses

Protein is a priority nutrient in the American diet, being fueled by the demands of weight loss drugs, diet culture, and new dietary guidelines. However, meeting these elevated protein goals sustainably requires diversifying beyond standard sources like whey protein isolate. 3D printing offers an opportunity to present a variety of protein sources in a palatable, customized, and consumer-acceptable format. In this study, 3 protein sources (cricket, whey, and pea), were optimized within food inks for 3D printing. Optimization involved different hydration levels, with whey requiring 7 grams of added water, cricket 22 grams, and pea the most at 47 grams. …

Mammalian Biodiversity Of The Easley Conservation Stewardship Area, Grayson C. Belt

Honors College Theses

Monitoring wildlife is an important part of conservation and is particularly vital for newly acquired conservation areas to provide a baseline of what is present. In 2025, the 22 ha Murray State University Easley Conservation Stewardship Area (MSU ECSA) was established following a donation to the university by Melissa Easley. I conducted a survey using trail cameras at the ECSA in fall 2025 and winter 2025/26 to record mammalian diversity. The survey consisted of two subprojects: a mesomammal subproject of 18 knee height trail cams and a small mammal subproject using 15 custom small mammal bucket cameras. I uploaded all …

Exploring A 'Fishy' Solution: Uncovering Human Norovirus Using A Zebrafish Model, Sahaana Chandran

Graduate Theses and Dissertations

Human norovirus (HuNoV) is the leading cause of acute gastroenteritis worldwide; however, the lack of robust laboratory culture systems and reliable animal models has limited progress in understanding viral replication and developing effective intervention strategies. While alternative models such as the zebrafish system have been explored, gaps remain in evaluating their ability to support replication across diverse HuNoV strains and in identifying factors that influence infectivity. This dissertation provides a comprehensive investigation into the use of the zebrafish model for studying viral replication, host interactions, and potential inhibition strategies. Initial studies focused on optimizing viral delivery methods using Tulane virus …

Low Methane Emissions From Nutrient-Rich Former River Channels In A Hydrologically Managed Dryland Delta, Siena Stassi, Jude A. Benavides, Chu-Lin Cheng, Marcelo Gomes Da Silva, Nicholas E. Ray, Nathan O. Barros, Rafael M. Almeida

School of Earth, Environmental, & Marine Sciences Faculty Publications

Anthropogenic stresses in dryland regions can alter hydrology, salinization, and biogeochemical processes. How these pressures influence methane (CH4) cycling and emissions from aquatic ecosystems remains poorly understood. Over the course of 1 year, we measured diffusive and ebullitive CH4 emissions from resacas—shallow, hydrologically managed distributary channels prevalent throughout the Lower Rio Grande Valley along the US–Mexico border. Despite warm, nutrient-rich waters, CH4 emissions from resacas were low, and more comparable to rates observed in estuarine systems. CH4 fluxes were positively related to temperature but negatively related to salinity and rainfall. Elevated salinity, driven by evaporation and source water from the …

Exploring The Spectrum Of Anxiety During Concussion Recovery: A Comprehensive Examination Of Symptom-Based Anxiety Disorders, Kori J. Durfee

Graduate Theses and Dissertations

Background: Anxiety is common following a concussion, arising from both psychosocial and physiological changes, and can manifest in diverse ways. Despite its complexity and association with worse outcomes, post-concussion anxiety is often assessed as a single construct. Characterizing anxiety presentations following injury may improve the identification of clinically meaningful symptoms and help inform future targeted interventions that can improve concussion outcomes. Purpose: The primary purpose was to determine if symptom-based anxiety disorders occur in adults with concussion and identify pre- and post-injury predictors associated with these disorders. Additionally, the clinical utility and predictive abilities of symptom-based anxiety disorders and variability …

Mechanisms Of Bacterial Glucokinase Inactivation Through Site-Specific Lysine Modification And Chemical Inhibition, Joseph Robert Will Andrews

Graduate Theses and Dissertations

Glycolysis and related metabolic pathways are controlled by various post-translational modifications (PTMs) that affect enzyme activity and metabolic flow. In E. coli, glucokinase (GLK) sits at the crossroads of glycolysis and the pentose phosphate pathway and carries out the first committed step of glycolysis: ATP-dependent phosphorylation of glucose. While it's known that glucose binding causes GLK to close its domains, how phosphate binding, lysine modification, and small-molecule inhibitors regulate GLK's shape and function is still not fully understood. Here, I combine structural biochemistry and enzymology to figure out how phosphate binding, specific mutations, and chemical inhibitors affect E. coli GLK. …

Evaluation Of The Weed Control Efficacy And Potential Economic Returns Of An Autonomous Weeder In Vegetable Production Systems, Claire Plassmeyer

Graduate Theses and Dissertations

Vegetable production requires intensive weed management. Conventional producers rely on herbicide applications to manage weeds effectively at low costs; however, growers are under pressure to minimize chemical use due to environmental concerns and increased incidences of herbicide resistance. Non-conventional systems, including organic and sustainably focused small-scale production, rely primarily on cultural practices and physical weed control methods, which are labor-intensive and costly due to limited labor availability and rising wages. These concerns have prompted the development of autonomous weeding devices, such as unmanned ground vehicles (UGVs) equipped with navigation sensors and implements to provide repeated, high-precision weed control. Compact devices …

Characterization Of Snrk1 Signaling In Rice Growth, Reproduction, And Stress Responses Using Phenotypic And Omics Analysis, Maria Clara Faria-Bates

Graduate Theses and Dissertations

SnRK1 is an evolutionarily conserved protein kinase belonging to the SNF1/AMPK family that is composed of a catalytic subunit (α) and two regulatory subunits (β and βγ), and it has a major role in adjusting growth in response to the energy status. SnRK1 phosphorylates and alters the activities of enzymes involved in metabolism and regulates gene expression by altering the activity of chromatin-remodeling enzymes or transcription factors. Rice contains three functional paralogs of SnRK1α: OsSnRK1αA (Os05g0530500), OsSnRK1αB (Os8g0484600), and OsSnRK1αC (Os03g0289100). Although SnRK1 is known to play a central role in plant growth and stress responses, the functional specialization of …

Bats And Bacteria: Infection Dynamics At The Human-Wildlife Interface, Isabella Katherine Deanglis

Graduate Theses and Dissertations

As the second most diverse mammalian order, bats host an array of pathogens, some of which are known to infect humans. Synanthropic bats share spaces with humans, resulting in bat-borne pathogen exposure. While most bat-borne disease research has focused on viral pathogens, bats host numerous bacterial pathogens with zoonotic potential. By integrating a global meta-analysis with field studies in Sub-Saharan Africa, I characterize the structural attributes that facilitate shared interfaces, the bacterial pathogens present in synanthropic bats of rural Kenya, and the physiological and environmental dynamics influencing odds of infection in these synanthropic bats. Finally, I evaluate the clinical relevance …

A Q-Methodology Study Of How Viewers Within The Southeastern Circuit Perceive The Future Of The Western Sports Industry, Molly Mckettrick

Graduate Theses and Dissertations

Western Sports occupy a unique position within American Culture, reflecting traditions rooted in agricultural communities and livestock practices, while also evolving as contemporary spectator events. Despite the growing visibility of Western Sports through media coverage on various digital platforms, there is limited research on how general audiences perceive the sport, which is the purpose of this study: to examine how viewers perceive the sport. This study examines viewer perspectives regarding the sport across various digital platforms, due to limited research on how general audiences perceive the sport while employing Q-Methodology to identify shared perspectives among spectators. A total of forty …

Conservation Wins And Woes: A Meta-Synthesis Of Ecotourism Impacts On Primates And Local Communities, Madison Lanie Mckinniss

Graduate Theses and Dissertations

Biodiversity assessments identify 612 extant species of primate, but ~50% of these species are at risk of extinction. Threats include agricultural and industrial production, urban development, and poaching. As concerns have grown regarding impacts on the environment, researchers have proposed ecotourism as a tool for conserving ecosystems while improving human welfare. Although conservation initiatives are pursued at these ecotourist sites, the presence of humans can cause additional influences on non-human primates (NHP). Primatologists have posed questions regarding implications of ecotourism on NHP, but research remains scarce. This study will investigate the practices executed at ecotourist sites where endemic NHPs reside. …

Applying Motivational Interviewing-Based Health Coaching Within An Existing Exercise Referral Program: A Cost, Implementation, And Effectiveness Analysis, Zachary Joseph Friedman

Graduate Theses and Dissertations

Higher levels of physical activity (PA) are known to be associated with lower rates of chronic disease and better quality of living. However, population-wide deficits in PA continue to demand strategies for supporting PA-related behavior change. Health coaching represents a promising intervention strategy for behavior change, but its effectiveness in generally healthy, non-clinical populations is not clear. The purpose of this project was to evaluate the feasibility, cost, and effectiveness of integrating student-delivered, motivational interviewing (MI)-based health coaching into an existing university-based exercise referral program (ERP). Additionally, this study aimed to use students as health coaches, and to document training …

A Survey Of The Collembola Of The Buffalo National River Park, Emma Renee Critchfield

Graduate Theses and Dissertations

Collembola are a neglected and understudied class with few recent U.S surveys. The aim of this thesis was to survey the Buffalo National River for Collembola and create a catalogue of all known species in the state of Arkansas, USA. Leaf litter, mosses, rotting wood, fungi and malaise trap samples were taken from 13 locations within the Buffalo National River park. In total, 14 families, 34 genera and 59 species were identified from 22,028 collected specimens. Of those, 31 species represent new state records. This survey also validates malaise traps as useful tools for Collembola sampling. The malaise trap samples, …

Unveiling Factors Influencing Extract Yield From Milled Rice In Brewing, Matthew Aitkens

Graduate Theses and Dissertations

Rice (Oryza sativa L.) presents a locally sourced, climate-resistant starch source for the brewing industry. As barley faces increased uncertainty due to rising temperatures, Arkansas-grown rice offers a more stable and cost-effective alternative starch source. However, the use of milled adjunct rice by brewers has remained limited, largely due to knowledge gaps about cultivar-specific properties relative to brewing. Chapter 1 provides an overview of rice as a brewing adjunct, reviewing the physiochemical properties important to brewing success. These properties include kernel size, kernel breakage, amylose content, and gelatinization temperature. Mashing strategies for multiple different brewing layouts are overviewed, showing practical …

Assessing The Potential Of Taming Chicken Gut Commensal Bacteria Using Random Transposon Mutagenesis, Arjun Chapagain

Graduate Theses and Dissertations

The chicken gut microbiome comprises hundreds of bacterial species whose functional roles remain largely unknown, in part because the tools needed to experimentally manipulate these organisms in their native community context have not been systematically developed or validated. This dissertation addresses the gap through three connected research chapters that progressively build a framework for transposon-based genetic delivery in the chicken cecal microbiome, moving from community-wide accessibility mapping to vector optimization to library preparation refinement. In Chapter 2, we established the community-level insertion landscape in chicken cecal metagenome using Himar transposon delivery via RP4 conjugation and aligned Tn-seq reads to a …

Assessment Of The Quality, Practicality, And Economic Viability Of Malted Rice, Bernardo Pontes Guimaraes

Graduate Theses and Dissertations

Climate change threatens the global supply of malting barley, creating a need for sustainable, climate-resilient alternative grains for the brewing industries. This dissertation investigated the chemical, sensorial, practical, and economic viability of using rice as a malting material. First, the malting and brewing qualities of 20 rice samples were evaluated. Results indicated malted rice (MR) had good malting and brewing qualities, including adequate levels of free amino nitrogen (FAN), high amyloglucosidase and limit dextrinase activities. Furthermore, pigmented rice varieties displayed a novel reddish-purple wort color. To identify rice cultivars suited for malting and brewing, the relationship between starch chemistry and …

Degradation And Metabolic Analysis Of Synthesized Quorum-Sensing Signals By The Model Eukaryote Chlamydomonas Reinhardtii, Adam Josef Bach

Theses and Dissertations

Bacterial organisms can “talk” with one another on a colony-wide scale using a communication system known as quorum-sensing (QS) via chemical signals. These signals are produced at a basal rate throughout the life of the bacteria and are classified as autoinducers, which diffuse across the cell membrane. Once the critical concentration is reached, they begin to diffuse back into the cell and initiate a phenotypic change. As these signals exist outside the membrane of their producer, they are also accessible to other organisms. It has already been noted that some plant species uptake these compounds through their roots and break …

Replacing Exams With Project-Based Assignments, Patrick Hiesl

Land-Grant Press — Teaching Section

This brief provides an example of project-based learning that was applied to the FOR 3410 – Wood Procurement Practices in the Forest Industry undergraduate course. After teaching this course for 4 years, it was determined that project-based learning aligned well with the learning outcomes and activities the students would encounter in their professional careers, resulting in better student engagement in the course and higher retention of the concepts.

The Delivery Dilemma: Unintended Consequences Of Cesarean Sections, Cecilia Odegard, Ellie Rose Piette

Celebrating Scholarship and Creativity Day (2018-)

Cesarean sections (C-sections) are a major surgical procedure intended to minimize the rate of maternal and infant mortality due to complications during birth. While they were originally intended to only be performed when medically necessary, rates of non-medically indicated C-sections have increased significantly. This poster examines the unintended consequences (UICs) that are associated with C-section delivery, focusing on both short-term and long-term effects. A major focus is how C-sections disrupt early microbial exposure during birth, which plays an important role in the development of the infant gut microbiome and immune system. Research has shown that infants born via C- section …

Nonenzymatic Glycation Of Human Serum Albumin Affects Its Structure, Properties, And Binding Interactions With Silver Nanoparticles, Monica Fairchild, Megan Kirk, Collin Kray

Celebrating Scholarship and Creativity Day (2018-)

Most nanoparticles (1-100 nm), upon contact with proteins, form a “protein corona” which can alter the structure and function of proteins. Human serum albumin (HSA) is the most abundant protein in blood plasma and acts as a major transport protein for numerous endogenous and exogenous compounds. In healthy individuals, 1-10% HSA is found in a glycated state, but significantly higher levels of glycated HSA (30% or more) are found in Diabetic individuals. This project investigates the effects of glycation on the structure, enzymatic activity, and antioxidant capacity of HSA and its binding interactions with silver nanoparticles (AgNPs) using a variety …

Climate Change-Related Effects On Carbon Emissions And Net Ammonification Across Lowland To Upland Soils From A High-Latitude Coastal Ecosystem, Jenna M. Ross, Karen H. Beard, Katharine C. Kelsey, Matteo Petit Bon, A. Joshua Leffler

Wildland Resources Faculty Publications

Warming, sea-level rise, and changing herbivory patterns are affecting ecosystem processes in northern coastal soils, including carbon and nitrogen cycling, although their combined effects are poorly understood. We studied the impact of these changes in a full-factorial microcosm experiment using four distinct soil types from the Yukon-Kuskokwim Delta of western Alaska. Soil was collected from three coastal wetlands, which differ in flooding frequency and use by migratory geese, and one rarely-flooded upland tundra used by geese in late summer. Microcosms containing these soils were incubated for 16 weeks at 10°C or 18°C, with or without three short-term floods, and with …

Survival Of The Fittest: Extremophilic Actinomycetes As The Future Of Antibiotic Treatment, Kyley Nelson, Ben Reddan

Celebrating Scholarship and Creativity Day (2018-)

The antibiotic resistance crisis is an emerging global health threat. In 2019 alone, 1.27 million deaths were attributed to antibiotic-resistant pathogens, and researchers predict the problem will worsen without intervention. Methicillin-Resistant Staphylococcus aureus (MRSA) has become a primary model for this crisis because it utilizes genomic adaptations to bypass β-lactam antibiotics. Although temperate actinomycetes have historically provided the majority of clinical antibiotics, recent bioprospecting has revealed that extremophilic actinomycetes represent a critical untapped resource. These organisms exhibit several adaptations to thrive in extreme environments, which results in the production of novel secondary metabolites and resilient extracellular enzymes. This literature review …