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Single-Atom Catalysts For Electrochemical Energy Conversion: Copper Single-Atom Catalyst For Oxygen Reduction Reaction And Quantification Of Site Density By Co Stripping Voltammetry, Dawatage Perera

Theses and Dissertations--Chemistry

Fuel cells are considered a promising technology for achieving cleaner and more sustainable energy production and utilization. However, one of the current major challenges is the economic viability associated with the extensive use of Pt group metal (PGM) catalysts, particularly on the cathode side. Therefore, non-PGM single-atom catalysts (SACs) have received considerable attention as alternatives for PGM catalysts in the oxygen reduction reaction (ORR), which occurs at the cathode of the fuel cell. Among various SAC structures, the non-PGM/nitrogen-doped carbon-based structure (M-N-C) stands out for its excellent ORR performance.

Chapter 2 illustrates the use of copper metal in place of …

Effect Of Π-Conjugated Ligands And A* Site Organic Cations On The Energetic Properties And Photovoltaic Performance Of Metal Halide Perovskites, Harindi R. Atapattu

Theses and Dissertations--Chemistry

Metal halide perovskites have gained interest in optoelectronic applications such as photovoltaics, lasers, LEDs, transistors, and photodetectors due to their excellent semiconducting properties considering their low cost. Metal halide perovskite (HP) photovoltaics have rapidly increased in power conversion efficiency (PCE), which now exceeds 25%. HPs have gained attention in these applications due to their high tolerance towards defects, long charge carrier diffusion lengths, high charge carrier mobility, high optical absorption, and bandgaps that are tunable over a large range. Even though HP photovoltaic PCEs are improved these are still not commercially available due to them showing lower stability and energy …

Ergot Alkaloid Consumption Alters Serotonin Receptor-Induced Vasoactivity In Ovine Umbilical Vasculature, James L. Klotz, Jessica L. Britt, Maslyn A. Greene, Coral Kent-Dennis, Susan K. Duckett

Animal and Food Sciences Faculty Publications

Consumption of ergot alkaloids during the second half of gestation has been shown to decrease umbilical artery vasoactivity resulting in decreased birth weights. Negative vascular effects of ergot alkaloids are mediated predominantly through serotonergic and adrenergic receptors in other tissues. Vasoactivity of serotonin (5-HT) receptors 5-HT_2A and 5-HT_1B/1D in umbilical artery and vein from ewes receiving endophyte-infected seed (E + 1.77 mg ergovaline/hd/d) or a control total mixed ration (CON; 0 mg ergovaline/hd/d) tall fescue seed at d-110 and d-133 of gestation was evaluated. Gravid reproduction tracts were collected from ewes. Two-mm sections of umbilical artery and vein …

Effect Of Chronic Cyclic Heat Stress And Supplemented Inorganic And Organic Zinc Source Levels On Grow-Finish Pig Growth Performance And Estimated Body Composition, Kayla M. Mills, Julie A. Mahoney, Alan W. Duttlinger, Sarah K. Elefson, John S. Radcliffe, Zachary J. Rambo, Brian T. Richert

Animal and Food Sciences Faculty Publications

Zinc (Zn) supplementation has proved to mitigate the effects of heat stress with varying effects evident with Zn source during acute heat events. However, the effects of Zn supplementation during long-term summer weather patterns have yet to be explored. Therefore, the objective of this study was to identify the effects of supplementation source and level of Zn to mitigate the negative effects of long-term, cyclic heat stress in finishing swine. Six hundred cross-bred pigs were housed under thermoneutral (TN) or cyclic heat (HS) conditions simulating summer heat with acute 3-d heat waves for a 70-d study. Thermoneutral conditions were 16.7 …

The 1-Back Matching/Mismatching Paradigm With Pigeons (Columba Livia): Evidence For Explicit Learning?, Daniel Peng

Theses and Dissertations--Psychology

With humans, a distinction can be made between explicit and implicit learning. language can be used to describe rule-based learning commonly seen in explicit, but not implicit learning. Unfortunately, we cannot do so with animals. Therefore, a non-verbal paradigm is needed to differentiate the types of learning. One method to make such a distinction is by training animals under a conditional discrimination task such as matching-to-sample with reinforcement delayed until a choice is made on the next trial: otherwise known as a 1-back procedure. In this experiment an alternating matching/mismatching to sample task under a 1-back schedule of reinforcement was …

Neural Hyperactivity During Value-Based Decision-Making In People With Daily/Near Daily Cannabis Use, Miranda Ramirez

Theses and Dissertations--Psychology

Value-based decision-making involves the coordinated effort of multiple brain regions to guide future choices based on past experiences. These processes are disrupted in cannabis use disorder, where individuals continue to use cannabis despite negative consequences. Reinforcement learning (RL) paradigms can be used to capture changes in the value of available options and may inform how the brain is impacted by frequent cannabis use. This study combined fMRI with behavioral modeling of probabilistic choice task data to compare value-based choices between young adults reporting daily/near daily cannabis use (CAN) and controls (CTRL). Participants selected one of two options reinforced ($0.25) at …

Characterizing Resting Cerebral Blood Flow In Obsessive-Compulsive Disorder With Arterial Spin Labeling, Hannah R. Wild

Theses and Dissertations--Psychology

Obsessive-compulsive disorder (OCD) is a condition characterized by intrusive thoughts (obsessions) and ritualistic behaviors (compulsions) profoundly impacting daily functioning and quality of life. Neuroimaging studies using various techniques have revealed inconsistent resting cerebral blood flow (rCBF) patterns in OCD patients, particularly within the cortico-striatal-thalamo-cortical (CSTC) circuit and sensorimotor network. Arterial Spin Labeling (ASL) MRI offers a promising, noninvasive method for directly measuring rCBF. This study, using data from the Yale HCP Trio study, analyzed unmedicated OCD patients and healthy controls, who underwent two consecutive resting pulsed-ASL scans. OCD patients with lower obsessional severity exhibited higher perfusion in the pre- and …

The Experience And Regulation Of Posttraumatic Shame Among Women With Interpersonal Trauma Histories, Jordyn M. Tipsword

Theses and Dissertations--Psychology

Posttraumatic shame – an emotion stemming from harsh attitudes about the self after trauma – is central to PTSD for many women following physical or sexual assault or abuse (interpersonal trauma [IPT]). However, knowledge of the frequency, intensity, and stability of shame in the daily lives of women post-IPT is lacking. Additionally, while some work has explored shame-specific emotion regulation (ER), or processes aimed at changing emotional responses, it remains unclear which ER strategies are effective in reducing shame, and the role of PTSD severity in shame regulation also remains unexplored. This project explored daily experiences and regulation of posttraumatic …

Extracellular Free Water As An Imaging Biomarker Of Neuroinflammation, Cristina N. Pinheiro

Theses and Dissertations--Psychology

Older adults experience a chronic state of heightened immune response referred to as “inflammaging” which can be observed by detecting levels of proinflammatory cytokines in blood serum. These proinflammatory cytokines are secreted in the central nervous system and may also enter the brain through the blood brain barrier. Previous literature has suggested that extracellular free water, a magnetic resonance imaging metric, may allow us to detect alterations in the extracellular space which are thought to correlate with inflammation in the central nervous system. This study examined the correlation between two proinflammatory cytokines, IL-6 and TNFα, collected longitudinally and cross-sectionally imaged …

A Mixed-Methods Study Exploring Free Nicotine Replacement Therapy As A Strategy To Promote Tobacco Treatment Equity At Cancer Center Cessation Initiative Sites, Marguerite A. Webster

Theses and Dissertations--Psychology

Nicotine replacement therapy (NRT) is a safe, efficacious smoking cessation treatment for cancer patients; however, equitable access is limited due to insurance gaps. Offering free NRT to patients with cancer has potential to increase tobacco treatment engagement and promote equity. This mixed-methods study aims to describe how some Cancer Center Cessation Initiative (C3I) sites implemented free NRT within their tobacco treatment programs (TTPs) to inform future development of equitable TTPs. Participating sites’ (N=9) TTP and patient population characteristics were assessed via survey and analyzed with descriptive statistics. Semi-structured interviews were conducted with 16 individuals and analyzed using directed …

Fluctuations In Alcohol Impairment Of Working Memory Across The Menstrual Cycle, William Mcgarrigle

Theses and Dissertations--Psychology

Behavioral endocrinology studies in women suggest that higher circulating levels of the ovarian sex hormone estradiol (E2) may be linked to better working memory performance, especially under conditions of cognitive impairment (e.g., age-related cognitive decline). Phases of the menstrual cycle characterized by different levels of E2 may therefore influence the degree to which women are vulnerable to alcohol impairment of working memory. The current thesis used a within-subjects design to test the hypothesis that women are less sensitive to acute alcohol-induced impairment of working memory when E2 is elevated during the menstrual cycle. A sample of 75 premenopausal women completed …

Disinhibition And Bac Estimation As Predictors Of Risky Driving Behavior While Intoxicated, Sarah Heymsfeld

Theses and Dissertations--Psychology

Alcohol-related driving fatalities persist as a public health problem in the United States. Recent studies have begun focusing on driver risk-taking as a factor in DUI occurrences and consequent driving fatalities. Key factors that could contribute to risky intoxicated driving are a lack of self-awareness concerning intoxication levels and consequent risk in addition to alcohol-induced increases in the driver’s impulsivity. Fifty young adult drivers received 0.65 g/kg of alcohol (target BAC = 80 mg/dl) or a placebo in a counterbalanced order on two different days and performed a simulated driving test that measured driver risk-taking as reduced distance to other …

Power Of Perception: The Role Of Perceived Caregiver Mindset Beliefs On Undergraduate Student Academic Engagement, Katherine R. Tanaka

Theses and Dissertations--Psychology

Promoting academic engagement is vital for college student success. Researchers have explored factors like growth mindset, the belief that intelligence can improve with effort, as a driver of academic engagement. Beyond personal mindset, students’ perceptions of key social influences, such as caregivers, also play a role. This study examined how undergraduate students’ own mindsets and perceptions of their caregivers’ mindsets relate to four components of academic engagement: behavioral and emotional engagement, and behavioral and emotional disaffection. Data from undergraduates (N = 1417) were analyzed using surveys, descriptive statistics, hierarchical regression, and exploratory moderation. Students generally reported both a personal …

Cognitive-Behavioral Effects And Sex Differences In Alcohol Use, Mia Radevski

Theses and Dissertations--Psychology

Addiction models (e.g., iRISA model) suggest that excessive substance use can result in behavioral consequences such as decreased response inhibition and increased salience attribution toward alcohol cues. The primary goal of this project was to explore potential sex differences in these characteristics of addiction. This dissertation is comprised of two separate but related studies. Study 1 investigated sex differences in inhibitory control and attentional bias. The central hypotheses are 1) women who reported heavy-drinking would display greater disruptions in behavioral inhibitory control following alcohol-related cues, 2) men who reported heavy-drinking would display greater attentional bias toward alcohol-related cues, and 3) …

Menstrual Cycle Phase And Hormonal Effects On Emotional Eating In Females With Attention-Deficit/Hyperactivity Disorder, Urveesha Nirjar

Theses and Dissertations--Psychology

Previous research has shown that cyclical fluctuations in ovarian hormones can predict changes in ADHD symptoms as well as eating behaviors, particularly emotional eating across the menstrual cycle. Previous studies have so far only examined the effects of estrogen (E2), progesterone (P4) and cycle phase in predicting individual symptoms or disorders such as ADHD or eating disorders or related behaviors separately. The aim of this study is to examine how emotional eating is influenced by naturally occurring hormonal and cycle changes in a sample overrecruited for ADHD. Seventy-eight individuals (assigned female at birth) with menstrual cycles overrecruited for ADHD provided …

Complexity, Entanglement And Codes In Quantum Field Theory, Nikolaos Angelinos

Theses and Dissertations--Physics and Astronomy

In recent decades many deep connections between quantum information theory and quantum field theory have been unearthed. In this dissertation we study topics in high-energy physics through the lens of quantum information: 1) We develop connections between error-correcting codes and Narain conformal field theories. 2) We study the entanglement entropy of one-dimensional fermionic chains with long-range interactions. 3) We study the temperature dependence of Lanczos coefficients and Krylov complexity.

Topics In Quantum Information, Complexity And Chaos, Debarghya Chakraborty

Theses and Dissertations--Physics and Astronomy

This dissertation explores quantum information, the use of codes to describe quantum field theories, and introduces new concepts to characterize the dynamics of quantum many-body systems. The contributions of this dissertation are the following: 1) We constructed Narain Conformal Field Theories (CFTs) using additive codes, where the modular bootstrap constraints translate into algebraic conditions on the codes, extending previous approaches. This helps express key CFT data, including the torus partition function, in terms of codewords. We constructed optimal Narain CFTs for small central charges, and described CFT ensembles for asymptotically large central charge with large spectral gap. 2) We studied …

Magnetic Spin Transport Coils For The N2edm Experiment, David C. Bowles

Theses and Dissertations--Physics and Astronomy

The n2EDM experiment is being construct at Paul Scherrer Institute to measure the electric dipole moment of the neutron (nEDM), in a search for new physics which could help explain the baryon asymmetry of the universe. To reach the experimental sensitivity goal of $d_n \sim 10^{-27}$, over an order of magnitude improvement from the current world limit, a spin polarization transfer efficiency of 99\% for ultracold neutrons entering or exiting the precession chamber is required, placing a stringent requirement on the adiabaticity of the magnetic field taper in the neutron guide system. The spin transport fields transition from 5~T (longitudinal) …

Qcd Analysis Of Flavor-Nonchanging Hadronic Weak Processes Through Next-To-Leading Order, Girish Lingadahalli Muralidhara

Theses and Dissertations--Physics and Astronomy

Studies in quantum chromodynamics (QCD), the fundamental theory of the strong interactions, of low-energy hadronic weak processes utilize an effective Hamiltonian framework. Below the weak-mass scale, an effective Hamiltonian contains a series of Wilson coefficients and four-quark operators that come from the operator product expansion in the Standard Model. The effective hadronic Hamiltonian pertinent to a weak process is then obtained via a renormalization group analysis in QCD from the weak-mass scale to the low-energy scale of O(2 GeV). In this thesis, the construction and phenomenological implications of such an effective Hamiltonian for flavor-conserving, parity-violating quark processes in the Standard …

Exploring The Hot And Gaseous Universe From Infrared To X-Ray, Chamani Gunasekera

Theses and Dissertations--Physics and Astronomy

Over 90% of baryonic matter in the universe exists as astrophysical plasmas. The gas
is often far from thermodynamic equilibrium, so numerical non-equilibrium spectral
synthesis simulations are used to understand observations. cloudy simulates vari-
ous physical conditions, providing spectra predictions. This thesis aims to meet the
challenge of new observatories like the JWST (James Webb Space Telescope) and
XRISM (X-Ray Imaging Spectroscopy Mission). These simulations are no better
than the underlying atomic and molecular database and the fourth chapter details
a long-needed update to an evolving database. The predicted spectra are strongly
affected by the composition of the gas, which …

Techniques For Optimizing Neutron Beta Decay Particle Detection, Austin W. Nelsen

Theses and Dissertations--Physics and Astronomy

Over the last couple decades, use of free neutron beta decay (n → p + e^- + ν_e) to extract the up-down quark transition element V_ud has become competitive with more conventional Fermi decays. Extraction of V_ud requires measurements of the vector to axial-vector coupling constant ratio λ and the free neutron lifetime τ_n. With a precise determination of V_ud, the 2.8σ departure from CKM unitarity can be addressed.

Nab, located at the Spallation Neutron Source at ORNL, will measure the electron-neutrino momentum correlation coefficient a (which couples quadratically …

Development Of A Source To Detector Simulation Of The Los Alamos National Lab Neutron Electric Dipole Moment Experiment, Dillon Buskirk

Theses and Dissertations--Physics and Astronomy

The Los Alamos National Laboratory (LANL) neutron electric dipole moment (nEDM) experiment is planning an increased precision measurement of the neutron’s permanent electric dipole moment. LANL nEDM expects to lower the statistical uncertainty to δd_LANL = 2 × 10−27 e cm after a year of live-time, which puts a more stringent upper bound on the nEDM. This statistical uncertainty is an order of magnitude less than the current best measurement set by nEDM at PSI. To reach this goal, the LANL nEDM collaboration requires a simulation tool that can tackle optimization problems, investigate systematic effects, and provide mock data …

Development Of A Novel Beam-Type Neutron Lifetime Experiment Using Ultracold Neutrons, Nicholas Floyd

Theses and Dissertations--Physics and Astronomy

Precision measurements of the neutron lifetime are critical to tests of the Standard Model. The CKM quark mixing matrix has recently been shown to deviate from unitarity in the top row, motivating the development of alternative extractions of the first element. Complementary measurements of the neutron’s lifetime and decay correlations can be used to accomplish this.

While the reported neutron lifetime by the Particle Data Group is taken from ultracold neutron (UCN) measurements, a separate class of experiments suggest a value in four sigma disagreement, meriting further study. The goal of the UCNProBe experiment at Los Alamos National Laboratory is …

The Application Of Novel Machine Learning Algorithms To Study Multi-Dimensional Fragmentation Functions Of Hadrons In Jets At Star, Hannah A. Harrison-Smith

Theses and Dissertations--Physics and Astronomy

Hadronization, the process by which colored quarks and gluons shower from high energy collisions and recombine to form stable, experimentally-observable particles, is a fundamental aspect of Quantum Chromodynamics (QCD) that is not yet fully understood. Fragmentation functions, typically measured in electron-positron collisions, encapsulate this hadronization process well for quarks. Studying proton-proton collisions offers direct access to gluon fragmentation that other channels like electron-positron do not. Recent theoretical developments have proposed the study of hadronic showers in groupings called jets, introducing the concept of multi-dimensional jet fragmentation functions. This thesis presents the extraction of collinear and transverse momentum-dependent fragmentation functions for …

Precision Neutrino Interactions In And Beyond The Standard Model, Kaushik Borah

Theses and Dissertations--Physics and Astronomy

This dissertation investigates precision measurements of neutrino interactions within the framework of the Standard Model and explores potential extensions beyond it. Neutrinos, often referred to as ghostly particles due to their weak interactions and elusive nature, have long been a frontier in particle physics. Through detailed theoretical modeling and comparison with experimental data, this work focuses on improving our understanding of neutrino-nucleon cross-sections, nucleon form factors, and generalized neutrino interactions. The study begins with a comprehensive examination of the role of vector and axial-vector form factors in neutrino-nucleon scattering and their impact on the interpretation of neutrino oscillation data from …

Mediators Of The Association Between Cognitive Function And Self-Care Behaviors In Patients Hospitalized With An Exacerbation Of Heart Failure, Jia-Rong Wu, Chin-Yen Lin, Abigail Latimer, Muna Hassan Hammash, Debra K. Moser

UK CARES Faculty Publications

Background: Patients with heart failure (HF) must engage in self-care, yet their self-care is often poor. Cognitive function commonly is impaired in HF and is associated with poor self-care. Heart failure knowledge and self-care confidence also are needed to preform self-care. Few investigators have examined mediators of the association of cognitive function with self-care.

Objectives: The aim of this study was to determine whether HF knowledge and self-care confidence mediated the association of cognitive function with self-care maintenance and management among patients with HF.

Methods: This was a cross-sectional observational study of 164 patients with HF. Cognitive function was assessed …

Primary Care Providers’ Experiences Treating Opioid Use Disorder Using Telehealth In The Height Of The Covid-19 Pandemic, Sarah Alexandra Marshall, Lachan E. Siebenmorgen, Katherine Youngen, Tyrone F. Borders, Nickolas Zaller

Nursing Faculty Publications

Background: The COVID-19 pandemic catalyzed a rapid shift in healthcare delivery towards telehealth services, impacting patient care, including opioid use disorder (OUD) treatment. Regulatory changes eliminated the in-person evaluation requirement for buprenorphine treatment, encouraging adoption of telehealth. This study focused on understanding experiences of primary care providers in predominantly rural areas who used telehealth for OUD treatment during the pandemic. Methods: Semi-structured interviews were conducted with 22 primary care providers. Participants practiced in 13 rural and 9 urban counties in Kentucky and Arkansas. Data were analyzed using conventional content analysis. Results: The pandemic significantly impacted healthcare delivery. While telehealth was …

Functions Of Translanguaging Practices And Teachers’ And Students’ Perceptions Of Translanguaging In Esl Universities, Dongyang Yuan

Theses and Dissertations--Curriculum and Instruction

Integrating research on both linguistic and semiotic resources of translanguaging practices, this research was carried out using a case study design to understand how translanguaging was used by both ESL teachers and adult language learners in the ESL setting, what functions translanguaging performs, and how teachers and students understand their translanguaging practice. Nine adult ESL learners at the intermediate level and an ESL teacher participated in this research. Data sources included observations, interviews, field notes, and reflective journals. Discourse analysis was used to analyze the transcription of observations and interviews. Results showed that participants used various forms of translanguaging, including …

Enrollment Management Leadership Response To System Changes: Case Study, Christopher R. Jensen

Theses and Dissertations--Educational Leadership Studies

While the impact of government funding for institutions of higher education has been researched extensively, little research looks at the impact of students as a funding source. This is important because students are one of the greatest contributors to higher education budgets. Within the Commonwealth of Kentucky, there has been a decline in high school graduates as well as state funding since the Great Recession in 2008.

This study uses systems theory as a theoretical framework to help understand the dynamic relationship between the external environment and institutions of higher education, as well as frame how leadership at regional institutions …

Onboarding New Administrators At Noblesville Schools, Janae Mobley

Theses and Dissertations--Educational Leadership Studies

While many organizations invest in their leaders when onboarding them for their new role; oftentimes this process can be overlooked in the K-12 school setting when it comes to school administrators. As a result, this study focuses on analyzing the needs of new school administrators and how to better support them in their role when transitioning to a new district or from the classroom. This study utilizes Mixed-Methods Action Research methodology to assess and address the needs of new school administrators at Noblesville Schools, a K-12 public school district in Hamilton County, Indiana.