Digital Commons Network^™

Leveraging Mammal Mycophagy To Determine Environmental Drivers Of Truffle Diversity, Brittany Hartsock

Electronic Theses and Dissertations

Many mycorrhizal fungi are hypogeous (truffle-forming), producing underground fruiting bodies. Studying truffles is inherently challenging due to their hidden nature. However, mycophagous mammals provide a unique opportunity to study hypogeous fungi because they rely on truffles as a food source. Although several truffle species have recently been described in the southern Appalachian region, their fruiting patterns remain poorly understood. To address this, we quantified truffle richness and spore loads from 670 Peromyscus scat samples collected across 42 sites spanning an environmental gradient during 2024 in the Blue Ridge Mountains of East Tennessee. We found that truffle richness and spore abundance …

Dialogic Communication Ethics As A Hopeful Response To Artificial Intelligence, Kristen Haldeman

Electronic Theses and Dissertations

Within the past five years, a new technology has dominated modern culture: artificial intelligence. With a multiplicity of ways to respond to this new environment, this dissertation situates a response to artificial intelligence by combining the media ecology and communication ethics perspectives. Media ecology explores historical roots and biases of technology to learn about their influence of humanity. A dialogic communication ethics seeks to find an opening for hope to emerge. Hope, grounded in the works of Jacques Ellul and the Christian tradition, offers a new rhetorical perspective by shifting focus away from technology and to our neighbor.

The Role Of Fast-Food Consumption, Residential Fast-Food Exposures, And Urinary Essential Trace Heavy Metals In Colorectal Cancer (Crc) Outcomes., Jeevan Adhikari

Electronic Theses and Dissertations

Background: Colorectal cancer (CRC) is a public health concern. Within the United States (US), fast-food consumption and environmental exposure to heavy metals have increased. The impact of fast-food consumption frequency from fast-food restaurants, residential fast-food exposures, and urinary essential trace heavy metals in relation to CRC outcomes have not yet been rigorously evaluated in the US. Methods: Within the LEAPS-CRC study, we used geographic information systems (GIS) and logistic regression to study the association of fast-food consumption, residential proximity to a fast-food outlet, and urinary essential trace metals with CRC incidence. Additionally, within Kentucky Cancer Registry (KCR) CRC cases, the …

Exploring Factors Influencing Care And Outcome Among Stroke Patients In Tennessee, Omodele Agbejimi

Electronic Theses and Dissertations

Introduction: Stroke is the fifth leading cause of death in Tennessee. Socioeconomic variables influence the delivery of stroke treatment and its outcomes. Despite advances in acute stroke care, the burden of stroke keeps increasing. This study aimed to explore literature on factors contributing to stroke care and outcomes in the U.S., assess the determinants of stroke patients’ outcomes, and examine the geographical disparities in stroke hospitalization and stroke death rate and their association with stroke care accessibility in Tennessee.

Methods: A scoping review was conducted using socio-ecological models to explore literature on factors contributing to stroke care and outcomes. A …

Political Ecologies Of The Livestock Industry, Jecca Bowen

Electronic Theses and Dissertations

In the United States today, livestock production is dominated by an intensified, industrialized production paradigm whose growth in recent decades has utterly transformed the logistical realities and community impacts of animal agriculture. This dissertation investigates the effects of this production paradigm on livestock producers—whose decision-making is shaped by multi-scalar and often contradictory forces—as well as residents living near these large operations. To do so, I draw upon mixed-methods fieldwork, including in-depth interviews, spatial analysis, and field odor measurements in Weld and Morgan Counties in northern Colorado. I also use political ecologies of emotion, embodiment, and health to examine the complex …

Racial Disparity And Environmental Influences On Perinatal Health In Jefferson County, Kentucky., Felicia A Pugh

Electronic Theses and Dissertations

Background: Severe maternal morbidity (SMM) risk has tripled over the past 30 years. Adverse infant birth outcomes in the U.S. have also increased with substantial Black-White disparities. Objectives: This work compares the frequency of adverse maternal and infant birth outcomes by maternal race (Black vs White) and examines associations between maternal ambient heavy metal exposures and birth outcomes in Jefferson County, Kentucky, 2017-2022. Methods: Jefferson County inpatient hospital delivery and birth certificate records of self-identified Black or White birthing parents were used. Incidence of SMM, stillbirth, preterm birth (PTB), and small for gestational age (SGA) with 95% confidence intervals (CI) …

Movement Ecology Of Sandhills Chub, A Carolina Endemic, Zachary Adam Ramsey

Electronic Theses and Dissertations

Fish movement studies have traditionally focused on species that support commercial and recreational fisheries, but recently more focus has been given to non-game, stream fishes because of their recognized importance in maintaining biodiversity within these ecosystems. Stream fish movement is described as being “restricted” and following a leptokurtic distribution via diffusive spread related to environmental and biological factors. Many studies of stream fish movement ecology in North America have occurred in high-gradient streams with coarse substrate in mountains or in streams of the interior plains. Sandhills streams of the southeastern USA are characterized as warm-water, low gradient, and dominated by …

Assessing The Relationship Between The Incidence Of Campylobacteriosis And Ecological Risk Factors In Tennessee, Emmanuel Angmorteh Mensah

Electronic Theses and Dissertations

Background: Campylobacteriosis although is the leading causes of bacterial diarrheal illnesses, have not gained prominent awareness and there are gaps in the understanding of transmission routes for sporadic, non-outbreak cases and their risk factors at the communal level to humans. This study, therefore, aimed to identify the campylobacteriosis risk factors and risk perception from the existing literature in the United States, determine the incidence and ecological risk factors for campylobacteriosis zip code level in Tennessee, and to perform spatiotemporal analysis of campylobacteriosis incidence cases in Tennessee.

Method: To achieve the first aim, a scoping review was conducted to synthesize …

Temporal Variation In Microbial Extracellular Enzyme Activity Along The Mississippi Gulf Coast, Jacqueline Pavlovsky

Electronic Theses and Dissertations

Microbial extracellular enzymes play critical roles in the degradation of organic matter and mineralization of nutrients in marine systems, yet few studies have examined how enzyme activity varies over short-and long-term timescales in nearshore coastal environments. In this study, I assessed day-to-day, week-to-week, and month-to-month variation in the activity of three hydrolases (phosphatase, β-glucosidase, N-acetylglucosaminidase) in seawater and sand at five beaches along the Mississippi Gulf Coast. In addition, the activity of two oxidases (phenol oxidase, peroxidase) was assayed in sand, and environmental factors determined at each site. Seawater enzyme activity showed more variation over time than between beaches and …

Microgravity-Induced Effects On Global Gene Fitness And Secondary Metabolite Yield In Bacteria, Gayatri Sharma

Electronic Theses and Dissertations

Bacteria are ubiquitous and capable of colonizing nearly any environment, including extreme conditions such as deep oceans, high altitudes, and even space-faring vehicles. These vehicles present unique stresses not found on Earth such as microgravity and radiation. As space exploration advances, understanding how microgravity affects bacterial life has become increasingly important. Over the past 60 years, studies using both real and simulated microgravity have revealed species-specific responses, collectively indicating broad changes in bacterial function and physiological adaptations.

Initially, this study examined Novosphingobium aromaticivorans, a lignin-degrading bacterium detected in spacecraft cleanroom environments by assessing gene fitness during growth in microgravity on …

An Integrated Data-Driven Framework For Coupling Upland Process Models And In-Stream Hydraulic Geometry Estimation, Ahmet Nazim Sahin

Electronic Theses and Dissertations

Large-scale watershed simulation platforms, such as the Agricultural Integrated Management System (AIMS), are essential for water resource management but are often limited by a critical lack of detailed in-stream channel data required for comprehensive river analysis. This study addresses this gap by developing and validating an integrated, data-driven framework that couples upland process models with in-stream hydraulic geometry estimation at a national scale. The research was executed through two complementary thrusts founded on the National Hydrography Dataset Plus (NHDPlus).

First, a geospatial workflow was developed to create NHDPlus-driven input files for the Annualized Agricultural Non-Point Source (AnnAGNPS) model—a tool for …

Heat Acclimated Algae Improves Heat Tolerance And Longevity In Daphnia, Ashit Dutta

Electronic Theses and Dissertations

Xenohormesis suggests that consuming stressed food provides physiological adaptation to the consumer for similar stresses. To evaluate this, Daphnia magna was provided with heat-stressed Nannochloropsis limnetica grown at 25℃ whereas the control group was provided Nannochloropsis limnetica grown at 12℃. In the heat tolerance experiment, Daphnia kept at 28℃ and 20℃ while consuming 25℃ algae had significantly higher heat tolerance compared to the control. Additionally, in stressed conditions, Daphnia consuming 25℃-grown food had significantly higher lifespan compared to the control. Next, Daphnia consuming 25℃-grown algae had significantly higher levels of antioxidants which could explain the lifespan extension. Finally, in fatty …

Elevation And Population Size Effects On The Survival Of Drosera Rotundifolia, Jessica Williams

Electronic Theses and Dissertations

Carnivorous plants face significant conservation challenges due to habitat destruction, climate change, and illegal harvesting. This study explores how elevation and population size influence key-life history traits of D. rotundifolia, such as flowering phenology, prey capture efficiency, seed production, and germination rates. Higher elevations and larger populations are associated with extended flowering durations and increased prey capture. However, seed production and germination rates show complex patterns that are likely influenced by genetic diversity, resource availability, or environmental conditions. These insights inform targeted conservation strategies, emphasizing habitat preservation, enhancing prey availability, and maintaining genetic diversity. Public education and community engagement …

Associations Of Natural Vegetation In Relation To Colorectal Cancer Hotspots And Colorectal Cancer Survival., Johnnie Newton

Electronic Theses and Dissertations

Background: Across Kentucky, county-level geographic disparities in colorectal cancer (CRC) incidence and outcomes exist. Given the heterogeneity of lifestyle, socioeconomic (SES), and environmental factors within a county, more granular approaches should be used to identify local areas with a high CRC burden and identify the area-level factors that may contribute to geographic disparities. Studies reported that living in greener areas is associated with beneficial health outcomes, including lower mortality. Despite growing evidence that natural vegetation (greenness) exposure is associated with increased physical activity and obesity, two well-known CRC risk factors, epidemiological studies investigating the association of residential greenness exposure with …

Environmental Factors (Rurality, Distribution Of Prescribers, And Altitude) Of People Who Died By Suicide In Montana, 2013- 2022, Anne N. Brown

Electronic Theses and Dissertations

Introduction: Suicide is increasingly prevalent in rural areas across the United States, especially in the western Rocky Mountain states. The connection between suicide and rural residency is not well understood, nor is the relationship between the distribution of prescribers, altitude, and suicide. Purpose: This retrospective quantitative study aimed to describe the characteristics of individuals who died by suicide in Montana and investigate the associations among rurality, distribution of prescribers, altitude, and suicide rate. Methods: Montana suicide mortality data for 2013-22 was used to describe individual characteristics. A second dataset was created for each Zip Code Tabulation Area (ZCTA) level in …

Pre-Columbian Soil Management, Settlement, And Land Use In Amazonia: Insights Using Micro-Regional Predictive Modelling In Gurupá, Brazil., Lauren Zacks

Electronic Theses and Dissertations

The results of a micro-regional predictive model of terra preta sites in the municipality of Gurupá are presented here. A Maximum Entropy approach was selected and modified to fit a presence-background model, rather than a presence-absence model typical of binary classifications. 13 known terra preta sites were used as input samples for the relative suitability model, with explanatory variables in the respective categories of topography, hydrology, soil type and vegetation index. A 30m spatial resolution DEM served as the basis for the former two categories, while additional TauDEM analysis was performed for the hydrology category. A Sentinel-2A mosaicked quarterly composite …

Developing Machine Learning Models For Selection Of Management Zones, Sravanthi Bachina

Electronic Theses and Dissertations

Soil sampling and analyses play a crucial role in optimizing nutrient management and enhancing crop productivity. However, collecting representative samples across diverse landscapes is challenging due to knowledge gaps about spatial variability of soil properties, large fields, multiple samples, and analysis costs. Collecting soil samples based on the management zones can help farmers gather precise information about soil properties with fewer samples. Recent developments in precision agriculture and machine learning. This study aimed to develop machine learning models that can learn, analyze, and refine landscape and soil properties data for automated selection of soil sampling zones and generating prediction maps. …

“Long Live Ear X-Tacy!”: An Oral History Study Of Rhetorics Of Nostalgia And Place., Aubrie Warner

Electronic Theses and Dissertations

This study aims to explore rhetorical placemaking through how people understand and construct narratives around places that no longer exist. In doing so, it examines the relationship between nostalgia and place — how rhetorical construction of place is influenced and/or informed by rhetorics of nostalgia, how our experiences influence our sense of place (past and present), and how we create continuity for ourselves in the construction and maintenance of particular narratives. This study contributes to the emerging field of rhetorics of nostalgia and places it in direct conversation with rhetorics of place and unpacks how these two are more connected …

The Relationships Between State-Level Economic Policies, Child Maltreatment, And Suicidal Behavior And Mortality., Yana B. Feygin

Electronic Theses and Dissertations

Suicide has proven to be difficult to predict and prevent at the individual level,1–3 so much so that a recent analysis of individual risk assessments found a maximal positive predictive value of 5.5% for suicide death,2 and suicide continues to be a leading cause of death among adolescents age 10-19 years.4 By targeting modifiable risk factors at the population level, policy has the potential to extend our reach to people and subgroups that are missed by individual level interventions. This ecological study of adolescent suicide rates, state policies, and child maltreatment in US states from 2005-2019 and Kentucky counties from …

Detecting Native Freshwater Mussels In Pennsylvania Waterways: Comparison & Validation Of Environmental Dna Methods, Meredith Bennett

Electronic Theses and Dissertations

North America is home to approximately one third of the world's freshwater mussel species. They are highly imperiled organisms due to habitat destruction and invasive species. Traditional surveys rely on visual identification of mussels, but individuals tend to be rare and difficult to identify. An alternative method is to extract environmental DNA (eDNA) from water samples, which has advantages over traditional sampling, including less sampling effort and fewer hazards to researchers and organisms. We conducted a review of the two main eDNA approaches: single-species detection and metabarcoding. We also developed and validated metabarcoding primers for the detection of native mussels. …

Understanding The Impacts Of Global Change: From Students To Microbes., Kylea Garces

Electronic Theses and Dissertations

Global change is a crucial process, affecting every organism, from the billions of humans on earth, to the billions of microbes in the soil belowground. Evaluating the impacts of the many drastic changes associated with global change is essential in advancing our understanding in how to mitigate these consequences. Alongside the production of basic ecological knowledge associated with these environmental changes, improving education practices to promote science literacy surrounding global change is another step towards a more optimistic future. This dissertation investigates global change from two standpoints: ecologically, where increased atmospheric nitrogen (N) deposition alters plant-fungal endophyte symbiosis, and pedagogically, …

Ground Level: Poems, Margaret Graber

Electronic Theses and Dissertations

“Ground Level” is a full-length poetry collection situated at the intersection of ecopoetics and psychology, where the theme of “grounding” one’s self continually emerges in the midst of personal geographical changes and experiences of collective social trauma during a period of prolonged immersion in the natural world. By exploring through an array of poetic forms, structures, and experimentations including golden shovels, contrapuntals, haikus, an abecedarian, a sestina, grounding exercises, poems featuring 20th century children’s television host Fred Rogers, and a sonnet crown which also explores queerness in the 21st century Southeast, the speaker engages with a number of different methods …

Effects Of Agricultural Chemicals On Native Plants Of The Northern Great Plains, Gabrielle Bolwerk

Electronic Theses and Dissertations

Agricultural chemicals are ubiquitous on the Northern Great Plains landscape and have negative impacts on non-target plant communities, even at small doses. Northern Great Plains grassland plant communities may experience herbicide drift from agricultural fields or be subject to livestock pharmaceuticals in grazing lands. My research objective was to evaluate if and how native plants are affected by agricultural chemical presence at different concentrations. In Chapter 2, I studied the effect of different concentrations of three common agricultural herbicides (2,4-D, atrazine, and trifluralin) on the germination, emergence, and growth of native plant species of the Northern Great Plains. I performed …

Revelations In The Blood: Determination Of Biomarkers And Analytes, Jeremiah Jamrom

Electronic Theses and Dissertations

Changes in body chemistry have long been utilized as a tool for medical diagnosis. Whether blood panel, toxin level, antigen testing or any of the myriad other tests performed annually, searching for molecules which confer health status is a long-established practice. These tests give physicians more information and allow them to make a more accurate diagnosis, from which appropriate treatment can stem. Awareness of, and the subsequent search for, biomarkers for disease states have grown substantially in the past years as analytical, biochemical, and instrumental techniques have become more precises and powerful. In an era of increasingly personalized medicine, novel …

Mejorar La Raza: Measuring The Implicit Anti-Black Racial Bias Of Multiracial Individuals., Katalina Traxler

Electronic Theses and Dissertations

This dissertation sought to examine if there are implicit anti-Black racial bias differences across multiracial people who identify as Black/White compared to multiracial people who do not identify as Black/White, accounting for age, citizenship, and education level. It was also determined if age, citizenship status, and education level moderate the relationship between multiracial identity and implicit anti-Black racial bias. The theories guiding this dissertation were: Heider’s Balance Theory, Multiracial Identity Development, and White Identity Development. The data were collected from Project Implicit, a non-profit organization and international collaborative of researchers who are interested in implicit social cognition. The data analysis …

Ecological Differences In The Associations Between Air Pollution, Greenness, And Risk Of Stroke: The Regards Study., Daniel W. Riggs

Electronic Theses and Dissertations

The adverse health effects of air pollution have long been recognized, with the majority of morbidity and mortality due to its effects on the cardiovascular system. Alternatively, living in areas with higher greenness has been found to be beneficial to a wide range of health outcomes. However, few studies have considered that these relationships may vary depending on the surrounding ecosystem. The purpose of this dissertation was to examine the effects of long-term exposure to air pollution and greenness on incidence of stroke, and how these relationships vary with the major ecological regions of the United States. We utilized the …

Investigating The Relationships Between Socioeconomic Status, Kratom Legislation, And The Covid-19 Pandemic On Opioid Overdose Mortality In The United States., Lyndsey Blair

Electronic Theses and Dissertations

Background: 585,000 people have died from an opioid overdose in the US between 1999 and 2020. The current opioid epidemic has been described as a quadruple wave of overdoses, due in part to the changes in prescription and illicit opioid supply as well as the underlying social and structural factors that led to a subsequent increase in demand. In order to mitigate the opioid epidemic through prevention and protection strategies, we must first understand the social and structural factors that are driving the increase in opioid misuse and abuse. To better understand the socioeconomic factors, we described socioeconomic profiles of …

Loggerhead Shrike Detectability And Occurrence In Coastal South Carolina Urban Areas, Michelle Krauser

Electronic Theses and Dissertations

Grassland birds, such as the loggerhead shrike (Lanius ludovicianus), are threatened by extensive land-use change, including urbanization. Loggerhead shrikes have been declining since the early 1900s and are rare or extirpated in portions of their former range. Obtaining reliable population estimates of loggerhead shrikes is important to identify demographic trends and ensure conservation decisions are based on an accurate assessment of their current status. Imperfect detection, or the inability to detect every shrike during a survey, can result in biased population estimates. Estimating detection probability is labor-intensive and requires assumptions that are difficult to satisfy in most field studies. Understanding …

A Review Of Current Methods In Avian Dietary Analysis And Their Integrated Application To Characterize The Trophic Niche Of Louisiana Waterthrush (Parkesia Motacilla)., Brandon Hoenig

Electronic Theses and Dissertations

Characterizing a species’ dietary composition presents an avenue to understand many facets of its ecological niche and can provide essential information for the species’ long-term conservation. To date, the vast majority of diet studies have relied on direct identification of prey during foraging observations or from diet samples to characterize the dietary habits of birds. However, advancements in laboratory-based approaches have revolutionized the field of trophic ecology by allowing researchers to indirectly infer dietary habits with higher resolution across greater time scales. Here, I apply two of these laboratory-based techniques, namely DNA metabarcoding and stable isotope analysis, to characterize the …

Detection, Occupancy, Abundance, And Mercury Accumulation Of The Alligator Snapping Turtle (Macrochelys Temminckii) In Texas, David Rosenbaum

Electronic Theses and Dissertations

Land use practices and physical alterations of ecosystems result in habitat loss and fragmentation, while chemical alterations, such as pollutant input, reduce habitat quality and health of exposed organisms. Here, I investigated the effects of watershed- and local-scale environmental variables on the occupancy, abundance, and mercury accumulation of a threatened aquatic species (Macrochelys temminckii, i.e., alligator snapping turtle) within the southwestern periphery of its distribution. Hierarchical modeling suggested the distribution of the species is more affected by watershed-scale land-cover than local habitat, and provided a baseline estimate of average species abundance across its range in eastern Texas. Abundance …