Digital Commons Network^™

Bottles, Butterflies, And Biomass: Recycled Glass Sand, Microbial Additions, And Herbivory Effects On Milkweed Growth, Kealey Skinner

Honors Theses

Plant-soil-microbe interactions are integral components of ecological networks and drive ecosystem function from the bottom-up. Whereas herbivores regulate ecosystem function from the top-down, having opposing and potentially complementary effects on ecosystem function. My thesis sought to understand how below-ground microbial communities contribute to herbivore preference and plant biomass across varied soil substrates. My thesis asked: how do substrate and soil microbial communities influence herbivore preference and plant biomass accumulation on swamp milkweed (Asclepias incarnata)? To address this question, seedlings of A. incarnata were sown in 2.5 cm wide × 10 cm deep pots filled with either natural beach sand or …

Distribution Mapping And Modeling Of The Invasive Japanese Knotweed, Jossalyn Rogalski

Masters Theses

This thesis investigates the distribution of invasive Japanese knotweed across Michigan. This plant poses significant challenges to land management due to its rapid growth, environmental impacts, and difficulty of removal once established. Using geographic information systems (GIS), remotely sensed data, and secondary environmental datasets, this research maps current infestations and analyzes key factors influencing the species’ growth and dispersal, such as soil composition, hydrology, land use, and a range of environmental variables, including climatic (annual mean temperature, temperature seasonality, annual precipitation, precipitation seasonality), elevation, vegetation and hydrological indices (NDVI, EVI, NDWI), percent tree cover, and distance to roads. Spatial analysis …

Disruption Of Energy Homeostasis By Chemical Mixtures Containing Persistent Pollutants In Hepg2 And C2c12 Cells, Morgan Jacobellis

All Theses

The Environmental Influences on Child Health Outcomes Fetal Growth Studies (ECHO-FGS) birth cohort data was used to identify chemical mixtures associated with adverse outcomes. This biomonitoring study associated specific chemical mixtures in maternal serum with low birth weight or childhood obesity (Pearce et al., 2021). Mixture Profiles 1, 3, and 4, comprised of different observed concentrations of DDE, PCB153, BDE47, and PFOS were prioritized. Mixtures were tested to determine whether they perturbed mitochondrial metabolism and energy sensing pathways. The purpose of this study was to elucidate a potential mechanism linking maternal exposure to mixtures containing persistent organic pollutants (POPs) to …

Field Pea (Pisum Sativum L.) Response To Planting Date In South Carolina Organic Cropping Systems, Tristan Lawrence

All Theses

Field peas (Pisum sativum L.) are not widely cultivated in South Carolina, resulting in limited agronomic data to support farmers interested in this crop. However, field peas hold significant promise as a cool season crop for both organic and conventional growers in the region. Most commercially available field pea cultivars are evaluated and bred for the Pacific Northwest, where environmental conditions differ substantially from those in the southeastern United States. Consequently, there is a lack of region-specific recommendations for successful cultivation in South Carolina. To address this gap, a two-year planting date study was conducted during the …

Forest Overstory Mortality & Recruitment Patterns Eight Years Following Wildfire In The Southern Appalachians, Ruth Cumberland

All Theses

In this study, we investigated patterns of forest overstory mortality and recruitment eight years after wildfire in a large wildfire site the Southern Appalachians, a topic that has not been thoroughly investigated to date. With evidence that pre-fire drought promotes post-fire mortality through impaired physiological function and increased fuel consumption, unknown patterns following wildfire are important to study under shifting climate and land-use conditions. In Chapter 1, three areas of interest were investigated: (a) functional group mortality response to wildfire effects, (b) temporal differences in early (1-3 years) and late (5-8 years) periods of delayed forest overstory mortality patterns following …

Polydactyl Precursors: Insights Into Early Tetrapod Locomotion From Polydactyl American Alligators, Trevor P. Brewington

All Theses

Several of the earliest tetrapod lineages exhibited polydactyl limbs, with seven or eight digits per limb rather than the typical five or fewer seen in extant lineages. How these digit configurations might have been used during terrestrial locomotion is unclear, given the lack of living models in which their performance can be studied and limited evidence from fossil trackways. However, polydactyly occasionally appears in natural populations of American alligators (Alligator mississippiensis), animals with body plans that broadly resemble those of early tetrapods. To test how polydactyl limbs similar to those of early tetrapods might have functioned on land, …

Modeling Repeated Evolution Of Polygenic Traits, Marshall N. Hoskins

All Theses

Understanding the genetic composition of adaptive evolution is a longstanding and primary goal of evolutionary genetics. Despite many advances in our knowledge of trait adaptation, it remains unclear how demographic changes and repeated selection might alter the expected genetic architecture of adaptation. We used forward-in-time genetic simulations to test and observe the effects of opposing, repeated selection regimes on a polygenic trait in populations with and without changes in demography to better understand the genetic alleles that underlie polygenic adaptation. To further illuminate how natural populations might evolve, we investigated the impact of mutation effect size, the role of dominant/recessive …

Identification, Pathogenicity, And Fungicide Sensitivity Of Itersonilia Perplexans Associated With Petal Spot Of Gerbera Cut Flowers In Colombia, Matheus Beger

All Theses

Petal diseases significantly affect gerbera cut flower production, as minor visual damage renders flowers unmarketable. Among those pathogens causing petal spots, Itersonilia perplexans affects some Asteraceae plants. However, this pathogen's impact on Colombian gerbera remains poorly studied. This study was designed to fill four gaps: molecular identification of Colombian isolates, confirmation of pathogenicity, standardized culture media, and fungicide sensitivity data. Four objectives were pursued: (i) isolate and identify the causal agent through sequencing the Internal Transcribed Spacer, Small Subunit and Large Subunit from the rDNA; (ii) evaluate pathogenicity on detached gerbera petals; (iii) identify optimal culture media for I. perplexans …

Developing Aero-Floating Treatment Wetland (Aeroftw) Scaffolds: A Non-Plastic Alternative To Conventional Plastic-Based Ftws, Ada C. Montoya Gomez

All Theses

This research was conducted to explore the possibility of constructing floating treatment wetlands (FTWs) without using plastic materials. FTWs are floating platforms that hold plants on the water’s surface, letting roots dangle within the water column, to help remove contaminants from contaminated water, especially in stormwater ponds. Many conventional FTWs are made with plastic components, such as mats and plastic cup containers, which can release microplastics into the environment over time. The goal of this project was to design and test a new type of FTW that does not depend on plastics to support FTW flotation. The study took place …

Evaluating The Impact Of Intercropping Vegetables And Cut Flowers On Yield And Conservation Biological Control, Alliance Igiraneza

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Specialty crops such as vegetables are some of the most susceptible to yield losses and increased management difficulty over time due to pests. One of the potential solutions to this problem, which aims at ensuring the sustainability of the sector, is using conservation biological control practices such as intercropping to increase diversity, while maintaining the economic feasibility and profitability of the system. This study was conducted to evaluate the impact of this management practice using Bell pepper (Capsicum annuum var. King Arthur) as the main crop, intercropped with flowers including zinnia (Zinnia elegans var. Benary’s Giant), sunflower ( …

Herbivory Of Phragmites Australis Along A Salinity Gradient In Connecticut Wetlands, Sydney H. Kolz

Honors Scholar Theses

Invasive Phragmites australis (common reed) is widely distributed in New England wetlands, where it often outcompetes native plants and decreases biodiversity throughout the food web. Controlling its invasion is a priority, especially in salt marsh habitat, but current management techniques are inefficient. Leveraging natural processes may improve control strategies, but in order to do so, we must first better understand how abiotic and biotic stressors interact and affect Phragmites. This study focuses on herbivory and salinity, two factors limiting Phragmites’ fitness. I measured soil salinity and quantified the damage of three herbivore guilds (i.e. gall-formers and stem-borers, leaf-chewers, and …

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 …

The Effect Of Including A Yeast Culture Containing Essential Oils In Receiving Cattle Diets On Growth Performance And Health, Taylor Deanna Foster

Animal Science Undergraduate Honors Theses

Due to the increased risk of bacterial populations developing resistance to current antibiotics, consumer perceptions surrounding the utilization of antibiotics use in cattle, and the endemic incidence of bovine respiratory disease (BRD) among growing and finishing cattle, alternative management strategies to improve the health of cattle must be developed. The objective of this study was to evaluate the use of a supplement containing a yeast culture and an essential oils blend (YEO) on the health and growth performance of stocker calves at high-risk for BRD. Crossbred male beef calves (n = 185) received on two separate dates were used in …

Influence Of Increased Supplementation Of Organic-Complexed Zinc To Beef Cows During Gestation: Effects On Preweaning Health Of Offspring, Naija N. Sharpley

Animal Science Undergraduate Honors Theses

The objective of this study was to determine the effect of increasing zinc supplementation from organic-complexed sources to beef cows during gestation on calf performance. In May 2025, during gestation, Angus crossbred cows were confirmed pregnant with female sexed semen (n = 83) and enrolled in the current study. Cows (4.7 ± 2 years of age and 531 ± 84.4 kg body weight, mean ± standard deviation) were allotted to 4 groups (20 to 21 cows/group) based on, sire of heifer calf, cow age, and cow body weights taken at weaning. Assigned groups received 1 of 2 treatments (2 groups/treatment): …

From Time-Series Generation And Model Selection To Transfer Learning: A Review And Comparative Analysis Of Pixel-Wise Approaches For Large-Scale Crop Mapping, Judy Long, Tao Liu, Sean Alexander Woznicki, Miljana Marković, Oskar Marko, Molly Sears

Michigan Tech Publications

Accurate and timely large-scale crop mapping is essential for crop management and food security. Over the past decade, a wide range of pixel-wise crop classification approaches have emerged for workflow elements including image preprocessing, sampling methods, feature selection, model architectures, and transfer learning strategies. To guide users in constructing robust workflows, we reviewed methods for supervised and transfer-learning-based workflow elements and propose selecting a crop-mapping workflow based on target-site sample size and domain shift from a sample-abundant source site. To comprehensively evaluate the reviewed approaches, we systematically analyzed how different time-series construction strategies, training sample sizes, variable sets, model architectures, …

Identifying The Role Of Human Dna Polymerase Delta During Human Cytomegalovirus Genome Synthesis, Rachel Laree Dansereau

Dartmouth College Master’s Theses

Human cytomegalovirus (HCMV) is a large double stranded DNA virus and member of the Herpesviridae family. Like all herpesviruses, HCMV presents with characteristics of persistent, lifelong infections that transition between lytic and latent states. The replication of the viral genome is traditionally thought to occur by a rolling circle mechanism, but this model is supported by little evidence. It is known that HCMV actively recruits several host proteins to viral replication compartments (RCs), including proteins involved in the DNA damage response (DDR). The exact mechanisms of how these proteins are used and in what ways they help the virus remain …

Using The Flexon Approach To Rnai For Analysis Of Gene Function In Gonadal Development In C. Elegans, Andrew D. Spalding

Undergraduate Theses

C. elegans, a nematode worm, was used as a model organism to analyze the developmental effects of knocking down the expression of genes that are both essential to worm viability and highly enriched in reproductive tissues. In earlier research, approximately 70 C. elegans genes were identified that are both gonad-enriched and essential. To prioritize which genes should be the focus of future studies, a new strain of C. elegans was produced with three specific genetic variations that: 1) silence essential, somatic gonad-enriched gene expression, 2) limit the effects of this gene silencing to the gonad, and 3) yield a …

Expanding Access To Noninvasive Spinal Neuromodulation For Pediatric Spinal Cord Injury Rehabilitation: A Comparative Device Study, Alice E C Palmer

College of Arts & Sciences Senior Theses

Paralysis following spinal cord injury (SCI) has traditionally been considered permanent due to the disruption of supraspinal input to spinal motor circuits. However, growing evidence suggests that spinal networks below the level of injury retain intrinsic motor-generating capabilities through central pattern generators. Transcutaneous spinal cord stimulation (scTS) is a noninvasive neuromodulation technique that delivers electrical stimulation through the skin to reactivate these spinal networks. Although prior studies demonstrate that scTS delivered through research-grade devices is safe and effective in adults and children with chronic SCI, clinical translation remains limited by lack of FDA-approved systems, high costs, and restricted access to …

Using A Toxic Aging Coin To Assess Hexavalent Chromium Neurotoxicity: Impact Of Cr(Vi) On The Blood-Brain Barrier, Liam Buchanan

College of Arts & Sciences Senior Theses

The US population faces simultaneous public health threats from both aging and environmental pollutants. Chief among these is hexavalent chromium [Cr(VI)], whose toxic effects in peripheral tissues are well-established but its effects on the brain are still understudied. Following previous results indicating hippocampal metals dyshomeostasis after Cr(VI) exposure, we aim to assess Cr(VI)’s impact on the blood-brain barrier (BBB), a key structure for brain protection. We exposed young, middle-aged, and geriatric rats of both sexes to low levels of Cr(VI) in their drinking water for 90 days, after which we used immunofluorescence and confocal microscopy to analyze tissues for evidence …

Cholesterol Effect On The P-Glycoprotein Conformational Dynamics, Zane Bunn

Biological Sciences Undergraduate Honors Theses

P-Glycoprotein (Pgp) is a human efflux pump that belongs to the ABC transporter family. This protein consists of two transmembrane domains (TMD) that convert between inward to outward facing configurations to remove a wide variety of structurally different compounds from the intracellular membrane into the extracellular space using ATP.  This non-specific efflux of compounds has brought Pgp to scientific light as having a major role in multi-drug resistance of many diseases, and researchers are focused on developing a deeper understanding of the protein. To further this understanding, this study analyzed how the structure of Pgp is affected by a 10% …

Hormonal, Cytokinetic, And Skeletal Response To A Single Weighted Vest Exercise Treatment: A Pilot Study To Determine Weighted Vest “Rucking” Treatment For Osteoporosis In Post-Menopausal Women, Eleanor Pell

Master's Theses

Osteoporosis is characterized by a deteriorating of bone tissue leading to brittleness and increased fracture risk that affects both men and women as they age. Postmenopausal women are of particular interest due to high risk of declining bone density, a characteristic of this population. Treatments for osteoporosis range from menopause hormone therapy, bisphosphonates, biologics, nutritional changes, and exercise. Load bearing exercise interventions have shown effectiveness for stimulating bone growth, but many factors such as lack of access, motivation, self-confidence or knowledge, prevent long term compliance. “Weighted vest rucking” refers to a variation of rucking, which is a form of exercise …

Companion Parrot Vocal Learning And Reproduction Of Human Speech Sounds, Karla Vilches Castaño

Master's Theses

Vocal learning is rare among animals but is well developed in parrots, which can imitate novel sounds and, in captive settings, reproduce human speech. This study helps address a larger evolutionary question about vocal learning. Specifically, whether vocal learning ability is best understood as a single generalized trait or as a multi-dimensional system in which different acoustic features can be learned and reproduced with varying degrees of fidelity. This thesis quantifies how closely companion parrots match their human tutors across three acoustic dimensions (spectrographic structure, intensity contour, and pitch contour) and tests whether mimicry accuracy varies among individuals, differs between …

Investigating The Taxonomic Uncertainties Of Potentilla Rupincola, Natalie Elizabeth Hieber

Master's Theses

Landscape stewardship is an integral role for land managers that becomes more important when rare or endangered species occur within managed areas. Conservation across the landscape is a primary concern for land managers, but resources allocated for conservation can be limited due to many competing goals. Taxonomic uncertainty surrounding rare and endangered taxa, particularly plant taxa, that have historically been classified solely using morphological features further complicates conservation planning. One such taxon is Potentilla rupincola, a rare plant endemic to the eastern Rocky Mountains in Colorado. For over a century, botanists have debated whether P. rupincola is a distinct species …

The Effects Of Impervious Land Cover And Red Tide (Karenia Brevis) On The Florida Manatee (Trichechus Manatus Latirostris) In The Gulf Coast Of Florida, Anna Compton

Honors College Theses

Red tide, caused by the dinoflagellate Karenia brevis, is an algal bloom event that occurs annually in the West Florida Continental Shelf. The algae releases brevetoxin, a toxin that can be fatal to wildlife in high concentrations. These algal bloom events are thought to be exacerbated by warming ocean temperatures and increased nutrient runoff from urbanization. Red tide is responsible for the mass mortality of various marine organisms like the Florida manatee (Trichechus manatus latirostris). This study analyzes the changes in nutrient runoff and sea surface temperatures, and how these factors affected red tide cell concentrations and Florida manatee mortalities …

2026 Workshop On Bridging The Gaps: Tackling Microplastics And Nanoplastics Challenges In Coastal Ecosystems, Shenghua Wu, Kaushik Venkiteshwaran, Melike Dizbay-Onat, Alexandra Stenson, Jinhui Wang, Tina Miller-Way, Ebenezer Nyadjro, Bhuvnesh Bharti, John Weinstein, Yi Bao, Shihui Shen, Valerie Longa, Shenghua Zha, John Cleary, Marty Lind

Workshops

This report presents the findings from the 2026 Workshop on Tackling Microplastics and Nanoplastics (MNPs) in Coastal Ecosystems, which took place in Mobile, Alabama. More than 140 experts from universities, government, industry, and community organizations gathered to address the increasing issue of MNPs in coastal regions.

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

All Dissertations

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

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

Biological Sciences Undergraduate Honors Theses

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

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

Biological Sciences Undergraduate Honors Theses

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

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

Health, Human Performance and Recreation Undergraduate Honors Theses

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

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

Analysis Of Developmental Cardiogenic Processes Mediated By Fox And Zinc-Finger Transcription Factors, Rajnandani Katariya

All-Inclusive List of Electronic Theses and Dissertations

Cardiogenesis is a highly choreographed biological process requiring the precise integration of gene regulatory networks to govern cell division, fate determination, and spatial positioning. Disruptions in these mechanisms lead to congenital heart defects (CHDs), which affect approximately 1% of live births globally. Due to the evolutionary conservation of cardiac signaling pathways and the structural homologies between the Drosophila dorsal vessel and the early vertebrate heart tube, Drosophila melanogaster serves as a powerful model for dissecting the fundamental mechanisms of heart development. This dissertation investigates the molecular orchestration of cardiac development, specifically focusing on the roles of the transcription factors Jumu …