Physical Sciences and Mathematics Commons^™

Computational Studies Of Triplet State Formation In Zinc Dipyrrin Complexes, Reuben Kwabla Adigbli

Electronic Theses and Dissertations

Zinc dipyrromethene complexes are promising earth-abundant photosensitizers due to their strong visible-light absorption and tunable excited states. To rationally design them for photocatalysis and photodynamic therapy, a molecular-level understanding of triplet-state formation is needed, but details of intersystem crossing remain unclear. To study the effect of π-extension, we synthesized an indole-substituted zinc dipyrrin complex: the dipyrromethane ligand was prepared from indole and mesitaldehyde, oxidized to the dipyrromethene, then coordinated with zinc. DFT and TD-DFT calculations determined ground and excited-state geometries and energies in different solvents, modeled absorption spectra, and visualized charge distributions. The results show how solvent polarity shifts energies …

Enterococcus Abundance, Distribution, And Environmental Controls At A Sandy Shoreline, South Carolina, Usa, Helen Kehoe

Electronic Theses and Dissertations

Water quality monitoring crucially protects the health of beachgoers around the world. However, water-adjacent sediments, such as sandy beaches, are known to harbor harmful bacteria, yet are not monitored despite their intensive recreational use. This project monitored the abundance of fecal indicator bacteria (FIB), specifically Enterococci, in sandy beach sediments at beaches routinely monitored for water quality in Myrtle Beach and North Myrtle Beach, South Carolina. Surface sediment core sampling (0-5 cm) in the swash zone was conducted once per month for 4 months at 24 beaches in tandem with state-accredited surf-water FIB monitoring using IDEXX’s Enterolert test (Standard Method …

Spatial Variation In Resource Use And Species-Level Trophic Niches Of White And Brown Shrimp In North Inlet–Winyah Bay, South Carolina, Josie Bryan

Electronic Theses and Dissertations

Atlantic white (Penaeus setiferus) and brown shrimp (Penaeus aztecus) are ecologically and economically important species in the southeastern United States, supporting coastal food webs and valuable commercial fisheries. To understand their trophic dynamics in the North Inlet-Winyah Bay estuary, we conducted a spatial and temporal analysis using carbon (δ¹³C), nitrogen (δ¹⁵N), and sulfur (δ³⁴S) stable isotopes to evaluate trophic position and basal source contributions across three habitat types (river, bay, and marsh). Linear models were used to evaluate the effects of size (rostrum–carapace length, RCL, in mm), habitat, and species on trophic position, as well as the effects of habitat …

Comparison Of River Plume Classification Methods Using In-Situ Data, Payton Merica

Electronic Theses and Dissertations

River plumes transport terrigenous materials into the ocean, such as nutrients, pollutants, or sediment. These plumes can be separated into regions, including the source region, near-field, mid-field, and far-field, historically defined broadly by the governing forces in each region. Existing methods for classifying these plume regions are limited and often only take into account a subset of influencing factors. This study seeks to compare prior plume region classification methods, such as the Froude number and Rossby radius of deformation, to dominant dynamics within each region using momentum scaling proposed by Garvine (1995). Comparisons were derived from observational data collected during …

Long-Term Trends And Drivers Of Commercial Shrimp Fisheries Across The Southeastern U.S. Atlantic Coast, Trinity Assels

Electronic Theses and Dissertations

Long-term dynamics of southeastern U.S. Atlantic commercial shrimp fisheries reflect interacting environmental and socioeconomic processes rather than uniform regional decline. However, integrated, multi-state assessments linking these drivers to fishery-dependent indicators remain limited for the region. This study analyzed over four decades (1980–2023) of confidential fishery-dependent data from coastal South Carolina, Georgia, and northeastern Florida, focusing on the region where white and brown shrimp dominate commercial landings. Segmented regression analysis was used to identify structural shifts in long-term trends of landings, participation, and catch-per-unit-effort (CPUE), while multiple linear regression models identified seasonal temperature variables associated with interannual variation in shrimp CPUE. …

Presence And Impact Of Herbicides On Intertidal Benthic Communities, Marco Sanderson

Electronic Theses and Dissertations

The growing reliance and widespread use of herbicides on a global scale is negatively affecting non-targeted biota and, consequently, their ecosystems. Herbicide levels and their impacts have been extensively researched around the world in riverine and lacustrine ecosystems. However, studies of the levels and effects of herbicides on coastal intertidal benthic communities have been lacking. This study focused on testing spectrophotometric methodologies for herbicides (atrazine and glyphosate) and documenting their presence and levels in sediment, water, and biotic tissue of intertidal coastal beaches and marshes of Waties Island and Singleton Swash, Horry County, South Carolina. A laboratory microcosm was employed …

Development Of Minimalist Trifunctional Building Blocks For Chemical Biology Probe Synthesis, Luke E. Bohrer

Electronic Theses and Dissertations

The completion of the Human Genome Project in 2003 generated expectations that genomic information would accelerate the discovery of new protein drug targets and FDA-approved therapies. However, many small-molecule drug candidates continue to fail in clinical trials, and much of the human proteome remains undercharacterized in terms of structure, function, and disease relevance. Chemical tools are therefore essential for defining protein function, mapping protein interactions, and identifying disease-associated molecular mechanisms. Among these tools, small-molecule chemical probes provide a powerful strategy for connecting biological activity with target identification, functional analysis, and the development of effective therapies.

This dissertation describes the development …

Developing Solvent Tolerant Microbial Membranes: Lipid Extraction And Laurdan Fluorescence Approaches For Biofuel Optimization, Gladstone Anku

Electronic Theses and Dissertations

The high demand for sustainable energy has increased interest in advanced biofuels, though production is limited by solvent toxicity to microbial hosts. This study investigated the role of lipid composition in modulating membrane fluidity and solvent tolerance using Bacillus subtilis as a model organism. Five strains were cultured, and membrane lipids were extracted and analyzed using thin-layer chromatography and gas chromatography–mass spectrometry; however, inconsistent results limited compositional characterization. To address this problem, reconstituted vesicles composed of phosphatidylglycerol (PG) and phosphatidylethanolamine (PE) were used as model membranes. Membrane fluidity was assessed using Laurdan fluorescence spectroscopy by measuring generalized polarization (GP) values …

A Large And Robust Legless Lizard (Squamata, Anguinae) From The Gray Fossil Site Of Eastern Tennessee, Justice D. Lamer

Electronic Theses and Dissertations

The early Pliocene Gray Fossil Site in Tennessee preserved an abundance of microfossils, including numerous anguid lizard specimens. This includes the following elements: dentaries, a pterygoid fragment, a jugal, frontals, parietal fragments, dorsal and caudal vertebrae, and many osteoderms. Because these specimens had not been placed taxonomically beyond the subfamily level, comparative anatomy of similar elements from extant anguids and some quantitative data were used to provide more refined identifications. Using these methods, it was determined that a new, robust type of Ophisaurus is represented at the Gray Fossil Site. Important novel features include relatively robust dentaries, fewer but broader …

Modeling Mean And Variability Of Anxiety In Ecological Momentary Assessment Data Using Mixed-Effects Location–Scale Models, Trenzy Odero

Electronic Theses and Dissertations

Ecological Momentary Assessment is a method of collecting repeated measures of people in real time within natural environments. This results in hierarchical data that has a significant amount of variation at the person level. The traditional linear mixedeffects models assume that the residual variance is constant, which might not be true when the residual variance varies among individuals as well as in time. This thesis uses mixed-effects location-scale (MELS) models to model the mean and variance of an EMA outcome together. By introducing the possibility of variability in residual variance within and across individuals and with covariates, the MELS framework …

Phase-Resolved Measurement And Arbitrary Mode Conversion Of Structured Light, Somayeh Ghazanfarpour

Electronic Theses and Dissertations

This dissertation presents a single-shot phase and amplitude retrieval technique based on spatial light modulator (SLM)-based digital holography. The proposed method enables accurate reconstruction of complex optical fields from a single interferogram, reducing sensitivity to environmental fluctuations and improving experimental stability compared to conventional multi-shot approaches. In addition, a programmable arbitrary mode converter is developed using SLM-based wavefront shaping. By introducing controlled astigmatism and engineering the differential Gouy phase between orthogonal components, the system enables flexible transformation between structured light modes, including Hermite–Gaussian and Laguerre–Gaussian beams. Numerical results demonstrate reliable phase recovery and efficient mode conversion, validating the performance of …

Data Governance Maturity, Ai Integration, And Equity In Colorado K-12 Public Schools, John R. Curtin

Electronic Theses and Dissertations

Colorado's 179 K-12 public school districts operate as autonomous governance units, each responsible for securing and managing student data assets that span health, financial, residential, and academic records. The accelerating integration of artificial intelligence (AI) and machine learning (ML) tools into administrative workflows, productivity software, and instructional platforms has fundamentally altered the risk landscape for student data, yet governance frameworks at the state, district, and school levels have not kept pace. This dissertation investigates whether Colorado's decentralized educational governance structure is institutionally capable of producing equitable, secure, and sustainable data governance outcomes in the AI era.

Drawing on Institutional Theory …

Some Results In Maximal Pattern Complexity, Casey Schlortt

Electronic Theses and Dissertations

For a finite alphabet 𝒜 and a sequence 𝑥 ∈ 𝒜^ℕ_⊬ , Kamae and Zamboni combined the ideas of block complexity and topological sequence entropy to define the maximal pattern complexity, 𝑝^∗_𝑛 (𝑥). They defined an aperiodic sequence 𝑥 over two letters as pattern Sturmian if it had the lowest possible maximal pattern complexity, 2𝑛. Later, Kamae and Rao extended their definition of pattern Sturmian sequences to be sequences over ℓ ≥ 2 letters which are not periodic by projection and have maximal pattern complexity ℓ𝑛.

This dissertation answers a question posed by Kamae and Zamboni …

Ka Here Tāngata:1 Mātauranga And Te Ao Māori In Biocultural Kākāpō (Strigops Habroptilus) Conservation Approaches, Sophie Perfetto

Electronic Theses and Dissertations

This master's thesis examines conservation as a form of living cultural heritage practice through the co-management of kākāpō (Strigops habroptilus), a critically endangered parrot and taonga species in Aotearoa New Zealand. Situated within ongoing histories of colonial dispossession and Western frameworks of land and species management, contemporary kākāpō conservation is shaped through the partnership between the Department of Conservation’s Kākāpō Recovery Programme and Ngāi Tahu. Drawing on semi-structured interviews collected during fieldwork from July to August 2025, this study examines how institutional partnerships structure decision-making, authority, and responsibility in contemporary conservation governance. Findings demonstrate that Māori knowledge systems …

Evaluation And Distillation Of Source Code Generation Tasks By Large Language Models, Danny Brahman

Electronic Theses and Dissertations

Large Language Models (LLMs) are predominantly assessed based on their common sense reasoning, language comprehension, and logical reasoning abilities. While models trained in specialized domains like mathematics or coding have demonstrated remarkable advancements in logical reasoning, there remains a significant gap in evaluating their code generation capabilities. Existing benchmark datasets fall short in pinpointing specific strengths and weaknesses, impeding targeted enhancements in models’ reasoning abilities to synthesize code.

To bridge this gap, this thesis introduces two novel contributions: CodeEval and CodeQual. CodeEval is an innovative, pedagogical benchmarking method that mirrors the evaluation processes encountered in academic programming courses. It comprises …

The Role Of Peat Matrix Structure In The Accumulation, Storage, And Release Of Biogenic Gases From A Variety Of Peat Soils Across A Latitudinal Gradient, Md Rajeun Islam

Electronic Theses and Dissertations

Peatlands store about a third of the global soil carbon pool and are among the most important natural sources of biogenic greenhouse gases, including methane (CH₄) and carbon dioxide (CO₂). While biogenic gas production in peatlands has been studied extensively over the last few decades, the physical controls that regulate how these gases accumulate within the soil matrix and their influence on gas dynamics as they get released to the atmosphere still remain uncertain. Most studies investigating biogenic gas dynamics in peatlands have inferred in-situ gas distribution either exclusively from measurements of gas flux releases, or …

Should I Stay Or Should I Go?: Evaluating The Role Of Climate And Weather Stressors On Moving Decisions In Southeast Florida, Arielle Perry

Electronic Theses and Dissertations

As climate and weather hazards intensify, Southeast Florida communities face mounting pressures that increasingly influence patterns of migration and immobility. This research examines evidence of climate migration in high flood-risk neighborhoods in Fort Lauderdale by exploring why some populations choose to stay, while others leave, in the context of a changing climate. Using focus group discussions, I investigate how climate and non-climate related factors shape mobility outcomes among residents in the city. Migration outcomes were primarily influenced by negative climate and weather hazard experiences, discontent with existing public in-situ adaptations, and non-climate disamenities, which eroded participants’ sense of place. Voluntary …

Estimating Body Size And Biogeography In The Genus Alligator, Madelyn M. Turala

Electronic Theses and Dissertations

Several studies have examined correlations between total body length (TL) and skeletal measurements in the American alligator (Alligator mississippiensis), with some measurements serving as stronger predictors of TL than others. Femur length (FL) has been found to be tightly correlated with TL in A. mississippiensis, and this relationship has been used to estimate body size of extinct crocodilians. This thesis demonstrates that the humerus, radius, ulna, and tibia are also strongly correlated with TL and useful for body size estimation in A. mississippiensis, and thus, can be applied to related extinct crocodilians. Additionally, species distribution modeling …

Adsorption Of Pfas On Bridged Functionalized Organosilica Materials, Elisha Lawerh Kabutey

Electronic Theses and Dissertations

PFAS are hazardous contaminants that have a devastating impact on human health and the environment. Their hazardous nature has led to the development of various adsorption methods for removing these contaminants from water sources. In this study, functionalized organosilica materials were synthesized from bis[3-(trimethoxysilyl)propyl] amine using the sol-gel method. The surface amino groups of the organosilica were converted into amine hydrochloride groups. Their adsorption properties were evaluated using salts of perfluorooctanoic acid, perfluorooctanesulfonic acid, and perfluorobutanesulfonic acid. Results showed excellent adsorption capacity of the materials. Adsorption of PFAS leads to particle agglomeration and flotation of the spent material. A column …

Modeling Water Quality And Cyanobacteria Blooms In St. Lucie Estuary, Florida, Mohmmad Masudur Rahman

Electronic Theses and Dissertations

The St. Lucie Estuary (SLE) on Florida’s east coast is vital for diverse aquatic life and provides essential services to local communities. However, the estuary’s health is threatened by water quality deterioration due to nutrient-driven phytoplankton blooms, particularly cyanobacteria, which have increased in frequency over recent decades. These blooms may worsen water quality by reducing dissolved oxygen, altering pH, and increasing turbidity. Moreover, some phytoplankton species, including Microcystis aeruginosa, a freshwater cyanobacteria species, produce harmful toxins, posing risks to both marine aquatic life and human health in this area. Primary nutrient sources in this estuary include watershed freshwater discharges, …

Atmospheric Remote Sensing Using X-Band Radar In The Marine Atmospheric Surface Layer, Daniel P. Greenway

Electronic Theses and Dissertations

Atmospheric remote sensors have always offered promising technological advancements for measuring atmospheric properties over large spatial areas at high spatiotemporal resolution – a feat not currently possible with present atmospheric measurement technologies. However, remote sensors do not measure these atmospheric properties directly; they rely on robust calibrations or conversions, complex mathematical inversion methods, and/or machine learning to retrieve these properties. These inverse methods rely on the selection of an objective function, a machine learning technique, and an accurate parameterization for atmospheric property estimation. By leveraging inverse methods to improve the characterization of properties measured by remote sensors, this work enables …

Stability Of Paraffin-Insulated Nitrogen-Doped Carbon Fiber Ultramicroelectrodes, Maxwell H. Kwakwah

Electronic Theses and Dissertations

Nitrogen-doped carbon materials can facilitate the reduction oxygen-oxygen bonds, a key step in electroreduction of both O₂ (an important reaction in energy applications) and H₂O₂ (an important reaction in sensing and biosensing). Our lab previously demonstrated that thermal decomposition of urea in the presence of carbon fiber (CF) results in an N-doped carbon material that exhibits good electrocatalytic properties for H₂O₂ reduction. However, previous methods of insulating single N-doped CF via laser heating of borosilicate capillaries and epoxy to prepare ultramicroelectrodes (UMEs) seemed to adversely affect surface nitrogen contents and electrocatalytic properties. More recent work that utilized paraffin to …

The Application Of Natural Language Processing Towards Auditing Of Unstructured Data: A Design Science Approach, Dennis K. Amoatey

Electronic Theses and Dissertations

Financial auditors must manually review large volumes of unstructured text that may include contracts, internal policies, footnotes, and journal entry descriptions. This time-intensive process introduces risk of human error and inconsistency. Despite advances in automation, no systematic approach exists for applying Natural Language Processing (NLP) to this problem at scale. Using a design science approach, this study develops a framework that demonstrates how NLP techniques can be incorporated across key phases in the audit process, including planning, internal controls evaluation, evidence gathering, and reporting. Initial evaluation through expert feedback had a mix of responses. While some argued difficulty with data …

On The Paleontology Of Belize, Alson Ovando

Electronic Theses and Dissertations

Paleontology can be considered an underrepresented and emerging area of science in Belize. A primary aim of this thesis is to provide a background of paleontology in Belize and present the first comprehensive study of Quaternary vertebrate fossils known from the country. Quaternary fossil sites across Belize include caves, rivers, and sinkholes. In addition to reviewing and assessing material from known sites, this thesis presents new information and discoveries that were made while investigating Belize’s Quaternary fossil record. This thesis also includes a geospatial model depicting ecoregions in Belize during the last glacial maximum. Overall, the results presented here demonstrate …

Stochastic Universal Differential Equations For Epidemiological Modeling: Uncertainty Quantification In Disease Transmission Dynamics, Alice Menaya Armah-Bonney

Electronic Theses and Dissertations

Epidemic forecasting requires not only predictions of expected case counts, but also quantification of uncertainty, although existing surrogate modeling frameworks for agent-based models remain fundamentally deterministic. In this thesis a Stochastic Universal Differential Equation framework is presented that extends the deterministic Universal Differential Equation approach by incorporating a learnable stochastic diffusion term, enabling calibrated probabilistic forecasts while preserving the mechanistic interpretability and computational efficiency of the deterministic baseline. In doing so, a two-phase training algorithm is introduced to ensure stable convergence and the framework is validated against the ensemble output from ExaEpi, an exascale agent-based model of a COVID-19 outbreak …

On The Algebraicity Of The Tic-Tac-Toe Matroid And Homogeneous Mixed Bowtie Systems, Benjamin R. Allen

Electronic Theses and Dissertations

This thesis is presented in two parts. First, we explore whether the class of algebraic matroids is closed under duality, a decades-old open question. We consider the Tic-Tac-Toe matroid as a potential candidate to answer the open question. The Tic-Tac-Toe matroid is known to satisfy many of the necessary conditions for a matroid to be algebraic and has a non-algebraic dual.  Second, we focus on decompositions of the complete mixed graph into mixed bowties. A complete mixed graph has between every pair of vertices an undirected edge and antiparallel arcs. A mixed bowtie is a graph consisting of two 3-cycles …

Extreme Precipitation Events And Population Exposure: Site Recommendations For The Future Tennessee Mesonet, Victoria G. Redlund

Electronic Theses and Dissertations

This study examines frequency of and population exposure to extreme rainfall events in Tennessee to guide the placement of future mesonet weather stations. Using 1991-2021 daily nClimGrid precipitation records, extreme events were defined as events of rainfall ≥50 mm. These events were collated on an annual scale and normalized alongside square-root-scaled population densities derived from Landscan to develop extreme rainfall vulnerability maps. Results highlight where extreme rainfall is most frequent relative to population densities in each county. The findings were compared with models of mesonet suitability and feasibility to determine how meteorological needs correlate with siting needs such as land …

Ontogeny And The Effects Of Perinatal Stress In The First Immature Skeleton Of Teleoceras Aepysoma (Perissodactyla, Rhinocerotidae), Joe Gajewski

Electronic Theses and Dissertations

Recovery of an immature fossil rhinoceros (Teleoceras aepysoma) skeleton (ETMNH 32999) from the Gray Fossil Site in Tennessee offers the first insights into the ontogeny of the species. ETMNH 32999 is interpreted to be a subadult male in an age class equivalent to ~17-20% of potential lifespan. Comparative analyses support the hypothesis that subadults of related taxa are typically ~91% of average adult size in most dimensions. However, certain cranial dimensions are substantially lower than expected in ETMNH 32999, averaging only ~74% of the average conspecific adult. Such departure from typical growth rates is suggested to be attributable …

Utilizing Physics Informed Neural Networks For Disrupted Signal Dynamics, Nicholas J. Joyner

Electronic Theses and Dissertations

Physics-informed neural networks (PINNs) have been used in many applications including engineering and physical sciences. PINNs allow the incorporation of a priori understanding of a process’ structure into the modeling. We attempt to leverage the PINN structure toward the evaluation of disruptions to classical dynamical models by combining elements of ordinary differential equations into our loss function with sigmoidal gating to balance the penalties for deviations from the data with those for structural deviations. This enables the identification of the signal structure and the limits of disruption influence. As a use case, we consider stock value from 2019-2021, which expresses …

Machine-Learning Landslide Susceptibility And Runout Modeling In The Nolichucky River Gorge After Hurricane Helene, Grace Braver

Electronic Theses and Dissertations

Extreme rainfall from Hurricane Helene (September 2024) triggered widespread landslides across the southern Appalachian region, highlighting the need for rapid landslide susceptibility assessments that capture both landslide initiation and downstream runout. Traditional susceptibility models often focus solely on initiation zones, limiting their ability to identify which slopes will generate destructive landslides or where material will travel. This study addresses that gap by (1) integrating Geographic Information System (GIS)-based machine learning susceptibility modeling using ArcGIS Pro: Maximum Entropy (MaxEnt) and Random Forest-Based and Boosted Classification and Regression (FBBC) and (2) the U.S. Geological Survey (USGS) Grfin (Growth, Flow, and Inundation) runout …