Drivers And Consequences Of Changes In Nectar Microbiome Composition Across Spatial And Biological Scales, Daniel A. Barker

Electronic Theses and Dissertations

Microbial communities inhabiting floral nectar, known as the nectar microbiome, are important mediators of plant-pollinator interactions. However, the ecological and environmental factors that shape the composition of these microbial communities remain poorly understood. While previous studies have examined the effects of a few microbial groups, typically independent of one another, on one plant or pollinator species, this dissertation takes a wide-scale approach to explore how abiotic conditions and biotic interaction’s structure microbial communities within floral nectar. Furthermore, I also quantify how variation in microbial richness and identity influences pollinator behavior and plant reproductive success.

This dissertation shows that microbial abundance …

Integrated Stem Education For In-Service K-5 Elementary Teachers: Definitions, Self-Efficacy, And Teaching Practices, Amani Alhassan

Electronic Theses and Dissertations

Increasing interest has been evident in implementing integrated science, technology, engineering, and mathematics (STEM) teaching in public schools. However, teachers need to be professionally prepared and increase self-efficacy in teaching integrated STEM in their classrooms. Little is known about how teachers' self-efficacy in teaching integrated STEM is related to teachers' practices around STEM integration, particularly in K-5 classrooms.

This convergent mixed-methods study involved surveys with open- and close-ended questions to determine the integrated STEM perceptions, definitions, classroom teaching practices, and self-efficacy level in teaching integrated STEM for 79 northeast Tennessee K-5 teachers. The study also investigated the relationship between teachers' …

Post-Harvest Storage Of Fuzzy Cottonseed: Quality, Airflow Modeling, And Energy Use, Elijah T. Porter

All Theses

Fuzzy cottonseed is a valuable byproduct of the cotton ginning process. When cottonseed exits the cotton gin, it often retains high temperatures and moisture contents. Once in a storage facility, the cottonseed needs to be conditioned for safe storage. The overall objectives of this study were to analyze quality changes in cottonseed according to storage conditions, determine the airflow resistance properties of fuzzy cottonseed, develop a computational fluid dynamics (CFD) model of a representative cottonseed storage facility, and analyze cottonseed aeration fan strategies, runtimes, and costs. Changes in quality dictate the allowable storage time for cottonseed and are impacted by …

Impact Of Activated Carbon On In-Situ Reductive Dechlorination Of Chlorinated Ethenes In The Presence Of Perfluoroalykl Substances, Katie Motta

All Theses

Perfluoroalkyl substances (PFAS) and chlorinated ethenes are frequently co-detected at contaminated sites, yet little is know about how PFAS influence the performance of in-situ reductive dechlorination processes, particularly in systems amended with activated carbon.

The objective of this research was to study the impact of PFAS on in-situ reductive dechlorination of chlorinated ethenes using activated carbon. This research aims to characterize the sorption behavior of PCE and TCE (and its daughter products) and PFAS (PFOS and PFOA) onto activated carbon, and to assess how this sorption influences PCE and TCE removal from contaminated media in the presence of activated carbon. …

The Effects Of Incremental Application Of Chemical Defoliants On Cotton Fiber Quality, Aashish Karki

All Theses

Leaf shedding is a natural process as cotton matures; however, this does not synchronize with harvest timing; therefore, defoliants are used to remove these leaves and improve harvestability of the bolls. A tractor-mounted boom sprayer is typically used to apply defoliants. However, this approach results in low penetration to the bottom canopy, poor defoliation, and, consequently, lower fiber quality. An autonomous robotic spraying system equipped with pulse width modulation technology enables targeted side-spraying of defoliants, overcoming the limitations of conventional over-the-top applications. However, limited information on staggered defoliation timing and its effect on cotton fiber quality is available. Thus, field …

Visor-Zt: A Visibility, Simulation, And Operational Resilience Framework For Zero Trust Security In Ros 2, Noah Tinker

All Theses

Robotic systems are becoming more and more prevalent in modern society, with Robot Operating System 2 (ROS 2) being the dominant operating system for these implementations. Its popularity can be attributed to its design, which is purpose-built for distributed systems and asynchronous communications. However, ROS 2 security is static and therefore less capable of responding to contemporary threats and network behavior. This becomes a greater issue when considering its applications in the military and defense sectors, where security is of the highest importance. In recent years, the U.S. Department of Defense (DoD) has implemented zero trust (ZT) security based on …

Did California's Mental Health Services Act Improve Mental Health? Evidence From Self-Reported Data, Bennett Rider

All Theses

This analysis evaluates the impact of California’s Mental Health Services Act (MHSA), which was implemented in 2006 to increase access and improve quality of mental health care for Californians. Difference-in-differences analyses were applied to evaluate the impact of the MHSA on the number of poor mental health days in the past month (PMHDs) that survey respondents had self-reported, relative to a control group with similar pre-policy trends. Using survey data from the Behavioral Risk Factor Surveillance System (BRFSS), this study found that the MHSA’s full implementation is associated with California respondents reporting 0.118 fewer poor mental health days in the …

Machine Learning Based Medical Ultrasound Image Classification And Grad-Cam Interpretation, Victoria C. Hemphill

All Theses

This work takes a step in creating a diagnostic tool for the classification decision process of Achilles tendinopathy using ultrasound images. An attention-based multiple instance learning model is developed to classify the images. Typically, doctors capture multiple ultrasound images of the Achilles tendon during a study to determine a complete diagnosis. Multiple instance models adopt this behavior by providing a single label for a set of instances (images). The images are grouped into ”bags” at the study level and passed into the model. The MIL model then uses its attention property to assign an importance score to each image to …

A Generalizable And Privacy-Preserving Framework For Anomaly Detection In Heterogeneous Iot Environments, Mahshid Rezakhani

All Theses

With the rapid growth of Internet of Things (IoT) devices across various sectors, detecting anomalies in such systems has become increasingly challenging. IoT environments produce diverse and evolving data streams, often lacking labeled examples, which limits the effectiveness of traditional machine learning models. These models typically require frequent retraining and struggle to adapt to new deployment conditions. This thesis proposes a flexible, privacy-aware framework for anomaly detection in multivariate time series data generated by heterogeneous IoT systems. The approach integrates a long short-term memory variational autoencoder (LSTM-VAE) with contrastive learning and adversarial adaptation, enabling the model to generalize across domains, …

Effectiveness Of Electrosynthesized Hydrogen Peroxide In Urease Inactivation For Stabilization Of Source-Separated Urine To Recover Urea, Brooke E. Covert

All Theses

The practice of separating urine at a building scale, rather than mixing with domestic wastewater to be treated at water resource recovery facilities, allows for concentrated urine to be directly treated with the aim of resource recovery. However, source separation and treatment present challenges during separation, storage, and transport. This study evaluated the use of hydrogen peroxide-producing electrochemical cells, which represent a technology that uses electricity as an input, to stabilize urine through cathodically produced peroxide to enable downstream water and nutrient recovery. The electrochemical cells have been previously shown to stabilize urine with electrochemically produced peroxide as an effective …

Grain Boundary Migration And Radiation Induced Segregation In Fe-Cr Alloys, Mohit Dhoriya

All Theses

Radiation-induced segregation (RIS) is a significant phenomenon that occurs in alloys subjected to irradiation, particularly in environments such as nuclear reactors. This thesis investigates RIS in ferritic Fe- Cr alloys through the use of Atomic Kinetic Monte Carlo (AKMC) simulations, focusing on the interaction between solute atoms and migrating grain boundaries. The study explores the influence of temperature, solute concentration, and grain boundary velocity on solute drag, a critical process driving RIS. The results show that solute migration is strongly influenced by the presence of vacancies and interstitials generated under irradiation, which are absorbed by grain boundaries and other defect …

Effect Of Cigarette Smoke Extract And Nutrient Deficiency On Energy Metabolism And Biosynthesis: An In Vitro Intervertebral Disc Explant Culture Study, Avery E. Madden

All Theses

Low back pain consistently ranks among the leading causes of disability worldwide, with degenerative changes in spinal intervertebral discs (IVDs) recognized as a key contributor. Degeneration arises from the disruption of mechanical and biological cues within the disc’s cartilaginous tissue, often exacerbated by aging or injury. In recent decades, cigarette smoking has also been identified as a significant risk factor, as IVD degeneration is more prevalent among individuals with a history of smoking. Smoke inhalation is thought to promote degeneration both directly, by exposing cells to water-soluble toxic chemicals in smoke; and indirectly, through nutrient deficiency resulting from vasoconstriction and …

Consumer Preferences For Blockchain Technology In Tracking Carbon Footprint And Organic Claims In Animal-Based Foods, Josie Nasekos

All Theses

In 2022, the United States Department of Agriculture (USDA) Partnerships for Climate-Smart Commodities (PCSC) program set aside over $3 billion to be invested in 141 projects for agricultural products produced using practices that reduce greenhouse gas emissions or increase carbon sequestration. Although the majority of the PCSC funding was canceled in 2025, save a few selected projects that could potentially receive funding under the USDA’s new Advancing Markets for Producers initiative, there is no USDA-certified label to verify the climate-smart commodities that already received funding or similar products that exist in the market. However, third-party verified carbon footprint labels can …

Association Between Gene Family Expansion And The Rapid Diversification Of Pleurocarpous Mosses, Meredith A. Cobb

All Theses

Mosses are the second most species-rich group of land plants. They represent a critical group for understanding the evolution and diversity of land plants. Mosses comprise two major groups, acrocarps and pleurocarps. Despite having a more recent evolutionary origin than acrocarps, pleurocarps are exceptionally diverse. The difference in species richness reflects a rapid species diversification, roughly coincident with the origin and diversification of flowering plants. The speciation events giving rise to pleurocarp diversity happened so rapidly, making it historically difficult to produce strongly supported phylogenies with which to test evolutionary hypotheses. One such hypothesis is whether large-scale changes at the …

An Empirical Analysis Of The Pitch Clock On Major League Baseball, David Langton Jr

All Theses

The pitch clock was instituted in baseball to speed up the pace of play and make the game more watchable. While it has achieved this effect, it may have affected other areas of the sport, like the balance between offense and defense and pitching injuries. This analysis explores the results of a difference-in-difference regression comparing MLB and AAA 2015-2024 seasons. Overall, it finds that pitching statistics were not significantly affected, including elbow injuries. This includes games, ERA, and times a batter is hit by a pitch. In fact, the number of home runs and walks both went down significantly by …

Effects Of Variation In Altitude And Temperature On The Restraining Force And Internal Gauge Pressure Of Constrained Dunnage Airbags, Charles R. Weaver

All Theses

Dunnage airbags are an increasingly popular choice for securing cargo. During transit, changes in ambient temperature and pressure can cause airbags to expand generating damaging horizontal compressive forces in the trailer or container. Previous studies have developed numerical models for the behavior of Kraft paper and woven polypropylene fabric dunnage airbags under standard conditions but do not account for the behavior of airbags under varied altitudes and temperatures. This study provides empirical data on the internal gauge pressure and restraining force dynamics of 4-ply Kraft, woven polypropylene, and polyvinyl chloride airbags under simulated altitude and temperature conditions. Tensile testing characterizes …

Determining The Impact Of Surface Roughness On Disinfection Efficacy Of Commercial Products Against Pseudomonas Aeruginosa And Staphylococcus Aureus Wet Surface Biofilms, Kayley Stallings

All Theses

Biofilms are resistant to many stressors including disinfectant treatments. Disinfection may be further complicated by biofilms formed on damaged surfaces, as the damaged parts provide bacteria a better place to attach and grow. To better understand the risks, a new method to standardize surface scratching, to emulate worn surfaces via surface roughness changes was developed. These surfaces were used to grow biofilms with an adapted standardized EPA method to determine disinfection efficacy differences on scratched and non-scratched high-density polyethylene (HDPE) and stainless steel (SS) coupons treated with commercial disinfectants [hypochlorite (CL)-based, hydrogen peroxide (HP)-based, and quaternary ammonium (QA)-based]. Post-80 grit …

Quantifying The Effect Of Initial Molecular Weight Distribution On The Degradation Of Linear Polyethylene At High Temperatures Using Dissipative Particle Dynamics, Cassandra L. Simpson

All Theses

Polyolefins are the primary contributors to greenhouse gas emissions and supply chain energy requirements with respect to other commodity polymers. In order to explore more efficient methods for recycling and upcycling these plastics, it is important to consider the kinetics of polymer fragments during the degradation process to more accurately reflect experimental outcomes. The molecular weight distribution of synthetic polymers is an important factor to consider when synthesizing, processing, and manufacturing industrial plastics. The breadth of this distribution, or dispersity, is determined by the ratio of the weight average molecular weight to the number average molecular weight, and is correlated …

Criminal Behavior Responses To Changing Penalties: Estimating The Impact Of Felony Theft Threshold Changes, Ezra R. Simmons

All Theses

This study estimates how criminal behavior changes in response to shifts in felony theft thresholds, contributing to broader evidence on the deterrent effects of criminal penalties. Using detailed incident-level crime reports, this study applies econometric techniques to evaluate how offenders responded to reduced penalties. Analyzed within is California’s Proposition 47, which raised the felony threshold for theft-related offenses from $450 to $950. The results show a significant increase in low-level shoplifting (approximately 21%) and more substantial rises (approximately 24% to 30%) in crimes within the threshold overlap ($450 to $950). Additionally, the value stolen in crimes below the $450 threshold …

Mammal Use Of Crossing Structures On Highways In The Southern Blue Ridge Mountains, Chloe E. Horton

All Theses

Road networks are a major driver of habitat fragmentation and wildlife mortality. Wildlife crossing structures (WCS) are a common mitigation strategy with the goal of maintaining landscape connectivity, reducing wildlife-vehicle collisions, and facilitating safe passage across highways. Most research on WCS prioritize large ungulates or carnivores, leaving potential gaps in our understanding of how diverse mammalian communities interact with these features. We investigated spatial, temporal, and behavioral patterns of small-, medium-, and large-bodied mammals using WCS in the southern Blue Ridge Mountains of North Carolina and Tennessee. Using remote camera data from structures on I-40 and I-26 collected from 2018 …

Biological Hydrogen Process Improvements By High Temperature Simultaneous Saccharification And Fermentation, Frank W. Jeffries V

All Theses

The hyperthermophilic bacterium Thermotoga neapolitana is established as a versatile organism for fermentative hydrogen (H₂) production. Batch experiments were carried out to investigate the cell yield, product yield, and kinetic parameter values for individual media containing five carbohydrates. The highest H₂ yield of 15.56±0.31 mmol-H₂/g-carbohydrate was reported for glucose medium. H₂ yield was measured to be 14.51±0.38, 14.44±1.15, 11.88±0.84, and 11.53±0.73 mmol/g for media containing xylose, cellobiose, arabinose and xylan respectively. Acetic acid yield followed a similar trend, where the obtained values were 0.470±0.01, 0.462±0.04, 0.431±0.01, 0.409±0.03, and 0.406±0.01 g-acid/g-carbohydrate for glucose, cellobiose, xylose, …

Small Stream Restoration In The Piedmont Of South Carolina: Comparison Of Evaluation Tools And Water Quality’S Effects On Salamanders, Camryn Lachica

All Theses

For many years, the United States Army Corps of Engineers (USACE) used the Guidelines for Preparing a Compensatory Mitigation Plan worksheets to guide pre-restoration evaluation and determine post-restoration mitigation credits in South Carolina. Recently, the USACE in South Carolina transitioned to the Stream Quantification Tool (SQT), which provides a more comprehensive assessment framework. Our first objective was to compare these assessment methodologies across different landscape types to determine what the SQT adds to mitigation calculations that were not considered in prior worksheets. We evaluated 16 streams in the Piedmont of South Carolina, with four replicates each of forested, suburban, urban, …

A Comparative Study Of Land Use Regulations And Impact On Coastal Estuaries, Mabel W. Dadzie

All Theses

The study presents a mixed method and longitudinal assessment of land cover change, estuarine land loss, and policy implemented to address the past and anticipated estuarine losses in the Cooper River and North and South Santee watershed over the past twenty years. This study uses National Land Cover Dataset from 2001 to 2021, NOAA’s SLR projection data and planning documents from 1990 to 2025 to examine policy evolution among ten major themes. The results illustrate significant changes in land cover, notably the transition of wetlands, agriculture, and forests to developed land, as well as an evident spike in the integration …

Striped Bass (Morone Saxatilis) Movement And Habitat Selection In The Edisto River, South Carolina, Jacob Hill

All Theses

Striped Bass (Morone saxatilis) are a commercially and recreationally important fish native to the Atlantic Coast of the United States. They possess a diversity of life history strategies, with northern populations tending to be anadromous and southern populations being primarily river residents. In general, southern populations are less studied, posing challenges for effective management. Between 2019 and 2024, we tagged 37 Striped Bass with acoustic telemetry transmitters in order to study seasonal migration patterns and summer habitat selection. We estimated migration probability for both the spring and fall Striped Bass migrations using data from an array of passive …

Association Between Hidradenitis Suppurativa And Obstructive Sleep Apnea: A Retrospective Cohort Study Using The Trinetx Dataset, Mihir K. Patil, Thomas Z. Rohan, Goranit Sakunchotpanit, Kaushik P. Venkatesh, Sofia Milosavljevic, Vinod E. Nambudiri, Alexandra Charrow

Department of Dermatology and Cutaneous Biology Faculty Papers

No abstract provided.

Supervised Machine-Based Learning And Computational Analysis To Reveal Unique Molecular Signatures Associated With Wound Healing And Fibrotic Outcomes To Lens Injury, Catherine Lalman, Kylie R. Stabler, Yimin Yang, Janice L Walker

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Posterior capsule opacification (PCO), a frequent complication of cataract surgery, arises from dysregulated wound healing and fibrotic transformation of residual lens epithelial cells. While transcriptomic and machine learning (ML) approaches have elucidated fibrosis-related pathways in other tissues, the molecular divergence between regenerative and fibrotic outcomes in the lens remains unclear. Here, we used an ex vivo chick lens injury model to simulate post-surgical conditions, collecting RNA from lenses undergoing either regenerative wound healing or fibrosis between days 1–3 post-injury. Bulk RNA sequencing data were normalized, log-transformed, and subjected to univariate filtering prior to training LASSO, SVM, and RF ML models …

Dealuminated Metakaolin In Supplementary Cementitious Material And Alkali-Activated Systems: A Review, Amany G. Micheal Prof., Mostafa Adel Elsebaei Eng., Maria Mavroulidou Prof., Maria Centeno Assoc. Prof., Rabee Shamass Senior Lec., Ottavia Rispolio Mrs.

Architectural Engineering

This paper presents a comprehensive review of dealuminated metakaolin (DK), a hazardous industrial by-product generated by the aluminium sulphate (alum) industry and evaluates its potential as a component in cementitious systems for the partial or full replacement of Portland cement (PC). Positioned within the context of waste valorisation in concrete, the review aims to establish a critical understanding of DK formation, properties, and reactivity, particularly its pozzolanic potential, to assess its suitability for use as a supplementary cementitious material (SCM), or as a precursor in alkali-activated cement (AAC) systems for concrete. A systematic methodology is used to extract and synthesise …

Evaluating And Mitigating Linguistic Discrimination In Large Language Models: Perspectives On Safety Equity And Knowledge Equity, Guoliang Dong, Haoyu Wang, Jun Sun, Xinyu Wang

Research Collection School Of Computing and Information Systems

By training on text in various languages, large language models (LLMs) typically possess multilingual support and demonstrate remarkable capabilities in solving tasks described in different languages. However, LLMs can exhibit linguistic discrimination due to the uneven distribution of training data across languages. That is, LLMs are hard to keep the consistency of responses when faced with the same task but depicted in different languages. In this study, we first explore the consistency in the LLMs’ outputs responding to queries in various languages from two aspects: safety and quality. We conduct this analysis with two datasets (AdvBench and NQ) based on …

Mpo: Multilingual Safety Alignment Via Reward Gap Optimization, Weixiang Zhao, Yulin Hu, Yang Deng, Tongtong Wu, Wenxuan Zhang, Jiahe Guo, An Zhang, Yanyan Zhao, Bing Qin, Tat-Seng Chua, Ting Liu

Research Collection School Of Computing and Information Systems

Large language models (LLMs) have become increasingly central to AI applications worldwide, necessitating robust multilingual safety alignment to ensure secure deployment across diverse linguistic contexts. Existing preference learning methods for safety alignment, such as RLHF and DPO, are primarily monolingual and struggle with noisy multilingual data. To address these limitations, we introduce Multilingual reward gaP Optimization (MPO), a novel approach that leverages the well-aligned safety capabilities of the dominant language (e.g., English) to improve safety alignment across multiple languages. MPO directly minimizes the reward gap difference between the dominant language and target languages, effectively transferring safety capabilities while preserving the …

Leveraging Reviewer Experience In Code Review Comment Generation, Hong Yi Lin, Patanamon Thongtanunam, Christoph Treude, Michael W. Godfrey, Chunhua Liu, Wachiraphan Charoenwet

Research Collection School Of Computing and Information Systems

Modern code review is a ubiquitous software quality assurance process aimed at identifying and resolving potential issues (e.g., functional, evolvability) within newly written code. Despite its effectiveness, the process demands large amounts of effort from the human reviewers involved. To help alleviate this workload, researchers have trained various deep learning based language models to imitate human reviewers in providing natural language code reviews for submitted code. Formally, this automation task is known as code review comment generation. Prior work has demonstrated improvements in code review comment generation by leveraging machine learning techniques and neural models, such as transfer learning and …