Digital Commons Network^™

Balancing Root-Zone Oxygenation And Rhizosphere Stability: The Impact Of Aeration And Hypoxia On Hydroponic Plant Growth, Christian D. Baker

All Graduate Theses and Dissertations, Fall 2023 to Present

As the global population and food demand continue to increase, growers must look to innovative and sustainable methods for plant cultivation. Hydroponics is a popular method of sustainable plant cultivation where plant roots are suspended over a liquid nutrient solution. Hydroponics uses less water compared to traditional agriculture because there is no evaporation or solution runoff. It also maximizes land use, requires fewer pesticides and herbicides, and enables year-round cultivation in controlled environments. However, indoor hydroponic systems rely on artificial lighting, which has higher energy costs than traditional farming methods. Optimizing growing conditions is therefore critical to ensure long-term economic …

Physics-Data-Hybrid Modeling And Control For Vtol Aircraft, Samantha Dawn Burton

All Graduate Theses and Dissertations, Fall 2023 to Present

Vertical takeoff and landing (VTOL) aircraft are hybrid aircraft having both a helicopter flight mode and a fixed-wing plane flight mode. The objective of this dissertation is to examine and evaluate a new approach, physics-data-hybrid (PDH), for VTOL aircraft modeling and control. The PDH approach combines traditional, physics-based methods (Newtonian mechanics) with data driven methods (a machine learning technique called a Koopman operator model) to create an efficient and accurate modeling and control framework—mitigating the disadvantages of the purely physics-based and purely data-driven methods. The PDH approach is used to model scenarios when the VTOL aircraft transitions between helicopter mode …

Flight System Development For A Bio-Inspired Rotating Empennage Experimental Unmanned Aerial Vehicle, Ashton Gilbert

All Graduate Theses and Dissertations, Fall 2023 to Present

Unmanned aerial systems, commonly known as drones, are increasingly used for research, environmental monitoring, and testing new aircraft concepts. Many commercially available drone flight controllers work well for standard aircraft designs, but they can be difficult to adapt for experimental vehicles that use unconventional control methods or require detailed monitoring during testing. This creates challenges for researchers who need flexible and reliable tools to safely evaluate new flight technologies. This work presents the development of a custom drone flight control system designed specifically for experimental research. The system integrates custom electronics and software that allow researchers to easily modify control …

Training General Educators To Collect Antecedent-Behavior-Consequence Data Using Behavioral Skills Training, Mckenna Larsen

All Graduate Theses and Dissertations, Fall 2023 to Present

Many schools use a three-tiered system to meet the needs of individual students. General education teachers are often not given the training to provide the supports they are expected to provide. Evidence shows that when interventions meet the need the student is trying to communicate, these interventions are more effective. This research looked at the effects of training that involved modeling, practice, and feedback, also known as Behavior Skills Training (BST), on general education teachers’ ability to collect data on students’ behavior. It also looked at how teaching educators to collect data influenced their belief in their ability to handle …

Just Energy Transition To A Low-Carbon Economy In The Arctic: The Case Of Alaska, Jus Tavcar

Arctic and Northern Studies

Increasingly, government jurisdictions are finding ways to reduce carbon use within their boundaries, but different locations use varied tactics to create low-carbon economies. Furthermore, not all cities, states, or nations focus on the issue of inequity and the need for justice in the transition, so that the transition costs are not far higher for already marginalized groups. Using Alaska, an Arctic petrostate, as a case study, my research question is: What form of a just energy transition best fits the needs of Alaska’s communities struggling with the impacts of climate change? To answer this question, my research is grounded in …

Serotonin 1b/1a Receptor Modulation On Probabilistic Reversal Learning In The Btbr Mouse Model Of Autism Spectrum Disorder, Magdalena R. Gonzales

Electronic Theses, Projects, and Dissertations

Autism spectrum disorder (ASD) is known for developmental disability that typically emerges around infancy and early childhood due to a possible combination of genetics, environment or a combination of both. A diagnosis of ASD is determined by behavioral measures due to the lack of reliable biomarkers. Such symptoms include social impairment, and restricted and repetitive behaviors. Restricted and repetitive behaviors often present as rigid behavior or behavioral inflexibility. Behavioral flexibility is often described as the ability to adapt to changing environments. Previous research has shown that serotonin (5-HT) 1B and 1A receptor upregulation may attenuate restricted, repetitive behaviors found in …

Ring Ring Goes The Telephone, Answer That Email: The Immediacy Of Information Communication Technologies And Their Effects On Employee Well-Being, Concepcion Rodriguez

Electronic Theses, Projects, and Dissertations

Rapid technological advances have resulted in information communication technologies (ICTs) with revolutionary capabilities, allowing employees easy access to the workplace without the impediments of time or space. Initial inception of ICTs in the workplace were expected to increase autonomy (Heller, 1989), but the ability to be reachable at any time proved disadvantageous to employee well-being by creating a culture in which immediate responses were expected and precipitating the psychological phenomenon of workplace telepressure, an overwhelming preoccupation and urge experienced by workers to respond to work-related messages (Barber & Santuzzi, 2015; Mazmanian et al., 2013). The current study centered on exploring …

Integrating Student-Mined Data In Youth Computer Science Learning: An Investigation Of Learning Outcomes And Educational Strategies, Alex Acquah

Open Access Theses & Dissertations

As data increasingly shapes participation in society, there is growing emphasis on preparing youth to engage with data through computer science education. Existing K-12 computing and data science curricula have expanded opportunities for learners to analyze and interpret data; however, many learning experiences continue to rely on datasets and inquiry structures designed by others, limiting authentic engagement, personal relevance, and learner agency. This dissertation investigates the integration of student-mined data in youth computer science learning and examines its influence on computational thinking, epistemic agency, and learning experiences among high school students. Using a qualitative approach, data collected from youths of …

Development Of A Standardized Evidence-Based Onboarding Process For Primary Care Providers In A Rural Health Setting, Corrie Goodier

Doctoral Scholarly Projects & Capstones

Primary care in the United States continues to face a critical provider shortage. This shortage is especially elevated in the rural regions of the country and is exacerbated by longstanding issues with subpar onboarding and high turnover rates. Failure to retain advanced practice providers in rural primary care settings further diminishes patient access to services, negatively impacts continuity of care, and complicates efforts to maintain patient trust in the nation’s delicate healthcare system.

Improved provider orientation and support processes within rural healthcare systems have the potential to increase satisfaction rates and productivity. The purpose of this DNP scholarly project was …

Study Of Fast Switching Metastable-State Photoacids And Controlled Drug Release From Polycaprolactone (Pcl) Vascular Scaffold, Rana Salman Abbood Abbood

Theses and Dissertations

Metastable-state photoacid (mPAH) has become a common tool for controlling and driving chemical processes with light. mPAHs with fast reverse reactions are desirable for precise temporal control or generating quick pulses of proton concentration. In this work, different approaches towards fast reversing mPAHs are studied. Experimental and computational results showed that stabilizing the charge–transfer intermediate is an effective way to increase the rate. A novel mPAH with a reverse reaction ≈500 times faster than the most widely used mPAH in methanol has been developed. Another water-soluble mPAH exhibited a reverse reaction with a rate constant of 7.8 s−1, the fastest …

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 …

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 …

Beyond Symptoms: Examining Perinatal Mental Health Care Among Black, Indigenous And People Of Color With Polyendocrine Metabolic Ovarian Syndrome, Vinaya Thomas

Electronic Theses and Dissertations

Perinatal mood and anxiety disorders (PMADs) are as a public health concern in the United States. Individuals from minoritized racial/ethnic groups face a significantly elevated risk of maternal morbidity, mortality, mental health disorders, and associated adverse outcomes. Emerging studies also reveal a higher likelihood of experiencing perinatal mental health concerns in individuals with polycystic ovarian syndrome (PCOS), currently known as polyendocrine metabolic ovarian syndrome (PMOS). People who identify as Black, Indigenous, or a person of color (BIPOC) face unique healthcare challenges given the added structural and social burdens. This online survey study aimed to 1) understand the relationship between PMOS …

An Assessment Of Accessibility And Affordability Of Inpatient Psychiatric Care In Tennessee, Kailee Havrda

Electronic Theses and Dissertations

Introduction: Access to mental health has seen changes over the past decade, but little research and attention have been given to access to inpatient psychiatric facilities. Inpatient psychiatric care is crucial for patients experiencing mental health emergencies who need immediate access to care. Gaps in spatial accessibility, affordability, and the access and assessment process were identified due to a lack of available information in the field.

Methods: Secondary data from the Tennessee Department of Health were used to assess financial accessibility through payer source charges and patient encounters, as well as through mapping of inpatient psychiatric facilities and conducting drive …

Kinesiology Department Chairs’ Perceptions Of Their Training And Preparation, Kason O’Neil

Electronic Theses and Dissertations

Department chairs are responsible for leading academic departments in higher education.  These individuals regularly make important decisions regarding such things as managing faculty and academic programming, overseeing budgets, and supporting student needs. Despite these responsibilities, many people become department chairs without receiving formal leadership training. This study explored how kinesiology department chairs across the United States viewed their preparation for the role and the importance of leadership training. A total of 111 department chairs completed an online survey about their background, previous training, and the importance of training for different administrative responsibilities. The results showed that most chairs had little …

Exploring Competitive Dynamics Between Pseudomonas Baetica And Salmonella In A Polymicrobial System, Braxton E.M. Stout

Electronic Theses and Dissertations

The global rise in antimicrobial resistance has catalyzed a greater focus on polymicrobial research aimed at characterizing microbial interactions and uncovering new therapeutic strategies. Though it has long been of interest, environmental soil-derived bacteria remain largely under-represented in research and thus uncharacterized in this field. This project aimed to identify soil microbes that display inhibitory mechanisms to potential nosocomial pathogens. Soil sample S1S3-2 displayed inhibitory phenotypes toward numerous bacteria and was identified as Pseudomonas baetica. In both planktonic and biofilm growth, P. baetica was able to inhibit Salmonella arizonae through a contact-dependent and temperature-dependent manner. Screening of a transposon insertion …

Kindergarten Teachers’ Perceptions Of Instructional Approaches For Teaching Sequencing Concepts: Worksheet, Hands-On, And Beebot-Integrated Lessons, Savannah P. Partin

Electronic Theses and Dissertations

The purpose of this qualitative multiple-case study was to explore kindergarten teachers’ perceptions of three instructional approaches for teaching sequencing concepts: worksheet-based instruction, hands-on manipulative instruction, and BeeBot-integrated instruction. Sequencing is a foundational early literacy skill that supports reading comprehension, story retelling, and understanding the order of events. Although sequencing is commonly taught through traditional instructional methods, limited research has examined how kindergarten teachers perceive the use of educational robotics as a tool for literacy instruction. The study was guided by constructivist theory, sociocultural theory, and developmental systems theory. Participants included six kindergarten teachers from a public elementary school in …

Perceptions, Attitudes, And Experiences Of Persons Who Work In Forensic Mental Health Systems, Abigail Wiser

Electronic Theses and Dissertations

The forensic mental health system serves clients with dual needs —serious mental health concerns like psychosis and suicidality, and management of risk. Experiences and perceptions of professional and direct care staff may impact daily and therapeutic interactions and client success. These experiences may be marked by stigma, such as beliefs about what led to hospitalization, treatability of mental health concerns, and intentionality of behavior. Understanding this stigma, as well as the role of vicarious trauma, workplace burnout, and other relevant individual factors, may help us understand staff experiences and guide training, thus improving client care. 146 staff members across three …

Phytochemical And In-Vitro Cytotoxic Analyses Of Flavonoid Species Isolated From Chromolaena Leivensis, Luke A. Bryant

Electronic Theses and Dissertations

As a leading cause of death worldwide, cancer and its treatments remain a primary source of interest among researchers. Modern studies are looking into bioselective cytotoxicity to create new chemotherapies that do not have the same harsh side effects as those we use today. Natural product research has a promising future for the development of such treatments. Specifically, polar flavonoids may be the key to a bioselective treatment. Such flavonoid species are native to plants, often within flower petals or within the body. A natural antioxidant, they are designed not to harm healthy cells. This study focuses on the plant …

Tennessee General Education Preschool Teachers’ Perceptions Of Their Preparedness To Teach Young Children With Disabilities, Misty M. Moody

Electronic Theses and Dissertations

Under the Individuals with Disabilities Education Act (IDEA), local education agencies (LEAs) must educate young children with disabilities in the least restrictive environment (LRE) while ensuring opportunities to learn alongside their non-disabled peers. As inclusive opportunities for preschool-aged children with disabilities continue to expand, general education preschool teachers play an important role in providing instruction that meets the diverse needs of all children. However, limited research has examined general education preschool teachers’ perceptions of their preparedness to teach young children with disabilities, particularly in Tennessee.

This qualitative study explored Tennessee general education preschool teachers’ perceptions of their preparedness to teach …

Intersectional Realities And Adaptive Leadership: A Phenomenological Study Of Black Women Administrators In Higher Education, Jocelyn Vernet

Electronic Theses and Dissertations

Existing literature consistently documents the acute underrepresentation of Black women in administrative leadership. Furthermore, Black women administrators that are represented and visible in higher education often oversee programs and task forces that heighten their experiences to high-risk situations. Emerging narratives suggest Black women employ effective coping strategies and embrace opportunities to strengthen and cultivate support networks while in their leadership roles. However, there is a significant lack in understanding how these strategies are structured and sustained to overcome the underrepresentation of Black women administrators in higher education. Additionally, basing their experiences solely through a survival lens limits a deeper understanding …

Supplementation Of Tannin Extracts And Islands Of Plant Diversity On Cattle Grazing Brome Grass Monocultures: Influence On Behavior, Welfare, Performance And Health, Bashiri Iddy Muzzo

All Graduate Theses and Dissertations, Fall 2023 to Present

Beef cattle grazing systems in the western United States often depend on grass monocultures that decline in nutritional quality during summer. As pasture quality decreases, cattle have fewer opportunities for selective foraging, grazing efficiency declines, and producers face increased supplementation costs to maintain animal performance, welfare, and effective pasture use. This dissertation examined whether interventions that provide phytochemicals either as a supplement or through the establishment of taxonomically diverse “hot spots” in otherwise monotonous landscapes could improve cow-calf pair performance and enhance the sustainability of agroecosystems. The study tested two strategies with free-grazing cow–calf pairs: supplementation with tannin extract and …

Efficacy And Engagement In Digital Acceptance And Commitment Therapy: A Meta-Analysis And Investigation Of Mechanisms, Korena S. Klimczak

All Graduate Theses and Dissertations, Fall 2023 to Present

Digital mental health interventions offer a more accessible, affordable, and flexible option for mental health support. These apps and websites draw from the same therapeutic models as face-to-face therapy, but are available on demand at a fraction of the cost. In exchange, digital formats give up the personal relationship, accountability, and scheduled structure that keep people connected to treatment. This places a greater burden on users to stay involved on their own, and as a result, engagement is widely believed to be the main bottleneck limiting the impact of digital mental health care.

This dissertation examined engagement in digital programs …

Psychometric Evaluation And Cognitive Correlates Of The Tactile Mental Cutting Test: Investigating Reliability, Validity, Gender Differences In Spatial Ability, Executive Function And Social Emotional Competence Among Native American Elementary Students, Sujata Basnet

All Graduate Theses and Dissertations, Fall 2023 to Present

Spatial ability-the ability to understand, visualize, and mentally manipulate shapes and objects-is important for learning in science, technology, engineering, and mathematics (STEM). However, many traditional spatial ability tests rely heavily on drawings and other visual representations and have often been developed and evaluated with populations that do not adequately represent culturally diverse students. As a result, there is a need for assessment approaches that are developmentally appropriate, engaging, and potentially more inclusive for young learners. The Tactile Mental Cutting Test (TMCT) provides one such approach by allowing students to explore three-dimensional objects through touch and physical manipulation while solving spatial …

Writing Assessment In Tennessee Community Colleges, Joshua Tucker

Masters Theses and Doctoral Dissertations

This mixed-methods study examined how composition faculty at Tennessee community colleges used margin comments to support student writing, whether those comments reflected principled or novice feedback language, and how instructors understood and described their own commenting practices. Marginal feedback remains the most widely used yet least theoretically examined form of response in first-year writing instruction, and the legislative reforms reshaping Tennessee's community college system, including the corequisite model, TNPromise, and TNReconnect have intensified questions about the pedagogical practices used to support an increasingly diverse student population. Eight full-time English instructors at Tennessee community colleges participated in the study, submitting 771 …

Gesture-Efficient Global Language Input Methods, Daniel Mailman

Masters Theses and Doctoral Dissertations

A central task of computer hardware and software is text entry: sending units of human written language to applications such as word processors and spreadsheets. Input units range from individual lexons (Unicode characters) to lexemes (words and compounds). Standard QWERTY keyboards directly access a limited set of lexons and are used to assemble lexemes one lexon at a time. Non-QWERTY lexons and lexemes often require (e.g.) layout switching, dead-key composition, candidate lists, memorized codes, or relatively sophisticated software input methods (IMEs). This dissertation presents µLex, a framework for gesture-efficient IMEs. µLex IMEs are designed to coexist with application and operating …

A Journey To The Midwest For Migrant Farmwork: Women's Testimonies Examining Their Lived Experiences Using Autoethnography And Plática Research Methodologies, Yesenia G. Alcalá

Theses & Dissertations

A JOURNEY TO THE MIDWEST FOR MIGRANT FARMWORK: WOMEN’S TESTIMONIES EXAMINING THEIR LIVED EXPERIENCES USING AUTOETHNOGRAPHY AND PLÁTICA

RESEARCH METHODOLOGIES

Yesenia Garza Alcalá, Master of Business Administration

University of the Incarnate Word 2026

The purpose of my research was to share the stories of five women who experienced a yearly migratory routine from Del Rio, Texas, to work in farms and factories in the Midwest, and how that annual journey shaped and educated us. The women are four of my older sisters and me, all of whom traveled and worked in the Princeville, Illinois, migrant camp, where we experienced the …

Correctional Officer Suicide: A Theory-Driven Investigation Of Acquired Capability And Suicide Behavior, Abigail R. Andersen

All-Inclusive List of Electronic Theses and Dissertations

A growing body of research suggests that correctional officers (COs) die by suicide at a significantly higher rate compared to the general population and some other public safety personnel. Despite what is known about this phenomenon, an understanding of the risk factors driving the high rate of suicide among this population remains unclear. Specifically, little attention has been paid to specific risk factors for suicide among this population and there is an overall absence of theory-driven research investigating CO suicide. The present study sought to address the gap in this area of research by investigating potential risk factors for suicide …

Characterization Of Regulation Of Ace2 And Morphogenesis (Ram) Pathway Components In Aspergillus Fumigatus, Devi Naga Jyothi Bale

Theses and Dissertations (ETD)

Aspergillus fumigatus CotA is a conserved protein kinase and predicted orthologue of Cbk1, a terminal kinase of the Regulation of Ace2 and Morphogenesis (RAM) network. In our previous study, disruption of CotA resulted in carbon source dependent invasive growth with the mutant exhibiting preferential growth on glucose but severely impaired growth on alternate carbon sources. This pathway in other fungi has been implicated in the regulation of morphogenesis, stress responses, and virulence, but this study is the first one to characterize it in the pathogenic filamentous fungus.  In yeast, the RAM network includes the CotA ortholog, Cbk1, and associated proteins, …

Extending Geometric Acoustic Ray Tracing To Multi-Room Environments: A Case Study On Gunshot Sound Transmission Between Adjacent Rooms, Tyler Ton

Theses and Dissertations

Accurate localization of gunshots in multi-room building environments remains a challenging problem in acoustic forensics and public safety applications. Existing approaches model sound propagation within a single room, neglecting the transmission of acoustic energy through walls and other building materials. This thesis presents a study on modeling multi-room gunshot acoustic transmission, combining geometric ray tracing with structural acoustic transmission-loss modeling to generate impulse responses for two horizontally adjacent rooms separated by a shared wall, providing a foundation for future inter-room gunshot localization work. The proposed system uses GSound-SIR, a geometric acoustics engine, to simulate sound propagation in both of the …