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The Haven Center: An Exploration of Alumni's Civic Engagement, Identity, and Self-esteem
No full textLeadership Policy and Organizations Department capstone projectThis mixed methods study explores the long-term impact of the Haven Center’s youth programming on alumni civic engagement, identity, and self-esteem. Drawing from 45 interviews with alumni and staff, findings indicate that alumni reported sustained civic participation, growth in self-understanding and personal identity, as well as positive self-esteem and confidence. Recommendations include implementing a knowledge management system, clarifying program theory of action, and elevating alumni voices. This study contributes to the broader understanding of how service-learning and early exposure in youth development programs can foster sustained personal development and indirect community impact.Dr. Claire SmrekarPeabody College of Education and Human DevelopmentDepartment of Leadership Policy and Organization
Chemical Transport Modeling for Polydimethylsiloxane-Based Microfluidic Devices
No full textPolydimethylsiloxane (PDMS)-based microfluidic devices (e.g. organ-on-chips) are increasingly important tools in biological sciences and engineering which may investigate biological processes at a miniaturized scale. However, PDMS is known to interact with hydrophobic chemicals and can strongly limit such chemicals’ in-device availability. Through a comprehensive transport model, one can predict in-device chemical concentration through finite element method (FEM) simulations using transport parameters derived from simple experiments. These parameters vary greatly between similar chemicals, revealing the limits of simple “read-across” methods in predicting chemical interaction. Chemicals may also undergo nonlinear transport via anomalous diffusion in PDMS. Through the framework of stretched-time fractional diffusion, this behavior may be characterized and modeled. The application of these methods allows a user of a naïve PDMS-based microfluidic device to extrapolate in-device concentrations under any geometric configuration or dosing regimen
Payment Reform for Vulnerable Populations
No full textThe United States health care system is increasingly moving away from the fee-for-service payment system and adopting value-based payment (VBP) models. However, the performance of these models for high-cost and high-needs populations has yet to be evaluated. To address this gap, I study the impacts of VBP models for three vulnerable populations: dual-eligibles, pregnant people, and Medicaid beneficiaries.
In Aim 1, I compare the differential impact of requiring Accountable Care Organizations (ACOs) to take on more financial risk in the Medicare Shared Savings Program (MSSP) for dual-eligible Medicare beneficiaries. I employ a two-part difference-in-difference-in-differences approach to determine whether the MSSP differentially reduced costs and improved health outcomes for dual-eligible beneficiaries after the implementation of the Pathways to Success rule change. The rule change differentially increased flu shots for the dual-eligible population but otherwise did not affect duals in different ways than Medicare-only patients.
In Aim 2, I determine whether maternity bundled payments are associated with changes in maternal health clinical and utilization outcomes in commercially insured pregnant patients. I use propensity-score matching within claims data from a large employer in the Southeastern United States to compare utilization and health outcomes for those who did and did not participate in a maternity bundled payment program. I find that participation in the bundle was associated with decreases in c-section rates, increases in the presence of major comorbidities and complications at birth, and decreases in emergency department (ED) and hospital use.
In Aim 3, I conduct a review of published and grey literature on Medicaid bundled payments in eight states to describe the types of bundles offered, their design, and state-level factors, and the impacts of these models on healthcare costs and quality across states. In total, I identified eight states offering a total of 109 bundles. States varied in important bundle design factors and state-level factors that may affect the design and performance of Medicaid bundles.
Overall, my results paint a mixed picture of the associations between VBP models and outcomes for vulnerable populations
Improving Faculty Collaboration Within and Across Networks
No full textLeadership and Learning in Organizations capstone projectThe Tennessee Board of Regents (TBR) prides itself on being a system that fosters a collaborative environment with workforce partners, community leaders, and the faculty across the system. This mixed-methods study sought to generate findings and recommendations assisting TBR in cultivating collaboration among community college faculty within and across its network. We synthesized a conceptual framework of shared navigation for comprehensive collaboration through network development and unpacked faculty perceptions of trust, psychological safety, and structural supports. Initial conversations with faculty, as well as survey results, indicated that TBR faculty perceived that TBR leadership makes system-wide decisions in isolation, without campus-level context or input, which frames the inquiry of this study.
Our approach through the lens of our synthesized, conceptual framework and literature-informed methods allowed us to reach the following findings:
1. There is a system-wide commitment to developing formal structural support for collaborative efforts across the TBR system.
2. Faculty members experience minimal psychological safety within the TBR network.
3. Faculty holds a limited perception of trust in collaboration spaces across the TBR system
Measurement Invariance of the AUDIT among Gender Minority Populations
No full textDespite evidence for putative risk factors for hazardous alcohol use among gender minority (GM) populations, it remains unclear whether GM groups differ from cisgender groups in overall risk for hazardous alcohol use, and evidence is mixed regarding hazardous alcohol use prevalence in GM groups compared to cisgender groups. Various threats to alcohol measure validity among GM groups may contribute to this mixed evidence base, and validating these measures may help clarify this ambiguity. We used cross-sectional data from the Healthy Minds Study (final sample n = 32,843) to assess the measurement invariance of the Alcohol Use Disorders Identification Test, one of the most commonly used measures of hazardous alcohol use, across multiple cisgender and GM identity groupings. We tested both one-factor and two-factor models for model fit as well as configural, metric, and scalar invariance across all groups as well as within pairwise comparisons.
The two-factor model of the AUDIT with correlated (1) consumption and (2) problems factors demonstrated superior fit to the one-factor model. For the one-factor model, we found evidence of configural noninvariance, indicating that the same factor structure could not be established across all groups. Pairwise comparisons similarly indicated poor configural fit. For the two-factor model, we were able to demonstrate configural and metric invariance (i.e., ability to equate factor structures and factor loadings) across groups, and we only found scalar noninvariance (i.e., threat to ability to equate item thresholds) on pairwise comparisons between cismasculine and cisfeminine groups as well as between cismasculine and genderqueer groups. However, with more lenient criteria for invariance, the two-factor model demonstrated adequate fit across all groups, supporting the use of the two-factor AUDIT to make comparisons among the tested gender identity groupings. Our study still contained many limitations, and both the AUDIT and alcohol measures more broadly remain mostly unvalidated among GM populations. More research is undoubtedly needed in this field.Thesis completed in partial fulfillment of the requirements of the Honors Program in Psychological Sciences
Developmental Programming of Hypothalamic Neural Circuits Integrating Fluid and Energy Homeostasis
No full textDrinking and feeding are coordinated homeostatic events, but our understanding of the development of their converging hypothalamic neural circuits remains rudimentary. Many environmental factors developmentally program neural circuits during critical periods in early postnatal life. Agouti-related peptide (AgRP) neurons are substrates of developmental programming, responding to nutritional cues during a critical period to reach downstream targets. The paraventricular nucleus of the hypothalamus (PVH) receives inputs from both AgRP neurons and the median preoptic nucleus (MEPO) to regulate energy and fluid homeostasis, representing a possible node of integration. We used TRAP2;Ai14 double transgenic mice to show a population of active neurons responding to water deprivation (Thirst-TRAP) overlaps with fast-refeed Fos induction (Hunger-Fos) in the PVH. To determine the age at which MEPO projections reach the PVH, we used DiI axonal labeling as well as Fos-labeling in response to hypertonic saline (HS). Our results indicate neurons in the MEPO project to the PVH and respond to HS by the end of the first week of life, and densities of Fos-labeled nuclei in the PVH do not peak until the second postnatal week, preceding innervation of the PVH by AgRP neurons. Based on these observations, we hypothesized perturbations to fluid homeostasis in neonatal mice may impact the formation of AgRP circuitry with sustained changes in ingestive behavior. Adult male mice exposed to HS treatment daily from postnatal day (P) 5 to P15 (HSPN) displayed significantly increased densities of AgRP axons in the MEPO and PVH, while female HSPN mice experienced a decrease in the MEPO. Short-term high fat diet (HFD) exposure leads to greater water intake in adult HSPN male mice, while long-term HFD leads to a significantly lower body weight gain in HSPN females. Moreover, a dehydration-anorexia challenge results in a sustained anorexic response HSPN males after rehydration, while a fast-refeed challenge results in a sustained decrease in water intake in HSPN males after refeeding. Together, these results suggest a sexually dimorphic effect of early perturbations to fluid homeostasis on the development of feeding circuits, with context-specific consequences for ingestive behavior
Essays on Big Data and High-Dimensional Models: Machine Learning Approaches in Econometrics
No full textThe increasing availability of high-dimensional and complex economic data presents both opportunities and challenges for econometric analysis. This dissertation, Essays on Big Data and High-Dimensional Models: Machine Learning Approaches in Econometrics, explores novel statistical and computational techniques for high-dimensional inference in threshold regression models and efficient data processing under multiway clustering. The three chapters collectively contribute to the advancement of econometric theory and practice by addressing critical methodological challenges in big data econometrics.
The first chapter develops a uniform inference theory for high-dimensional slope parameters in threshold regression models, allowing for either cross-sectional or time series data. It establishes oracle inequalities for Lasso estimators and introduces a debiased Lasso estimator for threshold models. The results allow researchers to perform uniform inference without specifying whether the model is a linear or threshold regression. The empirical applications to economic growth and the effect of military news shocks on U.S. government spending demonstrate the practical importance of this method in economic analysis.
The second chapter focuses on inference for the threshold parameter in high-dimensional threshold regression models. It derives the asymptotic distribution of the threshold parameter under different specifications, including kink, diminishing jump, and fixed jump models. The chapter rigorously proves the continuity of these asymptotic distributions and validates the use of subsampling for inference. The methods are applied to empirical settings where capturing nonlinearities and regime shifts is essential for understanding economic dynamics and informing policy decisions.
The third chapter proposes a novel method of algorithmic subsampling (data sketching) for multiway cluster-dependent data. It develops a new uniform weak law of large numbers and a central limit theorem for multiway algorithmic subsample means, demonstrating that algorithmic subsampling ensures robustness against potential degeneracy, and even non-Gaussian degeneracy, of the asymptotic distribution under multiway clustering at the cost of efficiency and power loss due to algorithmic subsampling. An empirical application using scanner data from Dominick’s Finer Foods illustrates the method’s effectiveness in demand estimation for differentiated product markets.
Collectively, this dissertation advances the intersection of big data econometrics and machine learning by developing theoretically rigorous methods for inference in high-dimensional threshold models and efficient data processing under multiway clustering. The findings have broad applications in economic policy and market analysis where large datasets and complex structural relationships are prevalent
Impact of Teamwork and Communication Training on Team Psychological Safety
No full textSchool of Nursing Doctor of Nursing Practice Program ProjectPurpose:
This Quality Improvement project evaluates the impact of teamwork and communication training, supplemented by post-surgical debriefs, on the self-assessed psychological safety of operating room (OR) teams. Adverse surgical events, affecting 14.4% of surgical patients despite safety protocols, harm not only patients but also families, providers, and communities. The literature identifies discomfort in speaking up as a primary cause of errors, as psychologically unsafe teams hesitate to raise concerns in the OR.
Methods:
Study participants, including physicians, anesthesiologists, technicians, nurses, and vendors, were selected by the site leader. Before the intervention, each person completed a baseline Surgical Team Member Experience Survey, adapted from Amy Edmondson’s Psychological Safety Survey. Training in communication and teamwork utilized modified TeamSTEPPS resources and was delivered via video or a tailored educational packet. Post-surgical three-question debriefs focused on successes, areas for improvement, and actionable steps, identifying issues in 59.4% of cases. After the intervention, participants completed the survey again and assessed their communication, teamwork, and confidence in speaking up, as well as providing open-ended feedback on process improvements.
Results:
Thirteen members from three high-performing surgical teams participated in communication and teamwork training, followed by six weeks of structured three-question debriefs after 79 surgical cases, which resulted in an 8% increase in self-reported psychological safety. Survey scores improved from 60 to 64.6 out of 70. Improvements were noted across all seven survey areas, aligning with existing literature on enhancing team communication and patient outcomes. Despite non-randomized team selection, the results highlight the potential applicability of the training to other surgical teams. Actionable items were identified in 44% of cases, highlighting the importance of refining communication, even in high-performing teams, to address challenges in high-stress environments such as operating rooms and healthcare in general.
Implications for Practice:
Interdisciplinary communication and teamwork training, coupled with structured debriefing, enhance psychological safety among surgical teams and show potential for broader application in healthcare. While the study's small sample size limits generalizability, it lays a foundation for further research. Future efforts should test these methods with less experienced teams and explore links between psychological safety, employee engagement, and retention amid workforce shortages. Remote implementation methods also warrant further study to assess their effectiveness and scalability
‘More Autonomy, More Burnout:’ Healthcare Transition Experiences of College Students Living With Chronic Illness
No full textEvery year, an increasing number of college students are living with a chronic medical condition. While much scholarly attention has been paid to the unique structural, psychosocial, and financial difficulties young adults face when transitioning from pediatric to adult healthcare, little is known about the healthcare transition experiences of college students living with chronic illness, who are simultaneously transitioning healthcare systems and transitioning to university life. To begin addressing this gap in the literature, I conducted a review of the literature examining pediatric-to-adult healthcare transition for adolescents and young adults followed by a series of interviews with college students in Nashville, Tennessee living with a chronic medical condition beginning in childhood. The literature review summarizes the state of the literature in emerging adulthood, college student development, and healthcare transition-readiness for adolescents and young adults with chronic medical conditions. Through the series of twelve interviews, I present a new perspective on transitioning to college with a chronic illness. I argue that the individualization and social development unique to the university environment and the consolidation of resources through student support networks can protect against several psychosocial challenges related to healthcare transition. Still, however, the process of transitioning to the college space acts as a confounding structural barrier to healthcare transition, exacerbating documented barriers to medical care for young adults with chronic illness. Further, I suggest that this paradoxical effect gives rise to recommendations for both healthcare systems and universities to better prepare young adults with chronic medical conditions for the realities of adult care and university life
From Adhesions to Z-discs: Regulation at the Cardiac Sarcomere by Distinct Paralogs of Alpha-Actinin and Myosin II
No full textGene duplications have endowed the vertebrate heart with multiple gene paralogs encoding key cytoskeletal proteins, enabling precise regulation of cardiac muscle function. This dissertation explores how distinct paralogs of myosin II and alpha-actinin contribute to the assembly, contractility, and function of the cardiac sarcomere, the minimal contractile unit in cardiac muscle. Experimental evidence suggests α- and β-myosin II-associated heavy chains (encoded by MYH6 and MYH7) exhibit distinct, non-uniform distributions within cardiac sarcomeres in both human iPSC-derived cardiomyocytes (hiCMs) and in vivo models. Signal against β-myosin II heavy chain extended further from the sarcomere center than signal against α-myosin II heavy chains, suggesting specific biomechanical tasks are partitioned between each heavy chain during cardiac contraction-relaxation. Selective inhibition of β-myosin II disrupted sarcomere assembly in hiCMs while depletion of β-myosin II alone did not, suggesting functional redundancy during assembly between β-myosin II and α-myosin II. α- and β-myosin heavy chain ratio within a cardiac myocyte influenced β-myosin II inhibitor sensitivity, suggesting atrial and ventricular myocytes may be disparately impacted by pharmacological inhibition. Next, evidence is presented concerning distinct alpha-actinin proteins encoded by gene paralogs ACTN1 and ACTN4. In vitro assays support the essentiality of ACTN1 in anchoring early sarcomere precursors at cardiac myocyte focal adhesions, ensuring proper sarcomere assembly. By contrast, evidence suggests another closely-related “non-muscle” alpha-actinin, ACTN4, localizes to the mature cardiac Z-disc (the sarcomere border) and destabilizes sarcomeric actin cross-links. Depletion of ACTN4 increased sarcomere length, elevated contractile force, and triggered cellular hypertrophy in cardiac myocytes, plus contractility-driven biomechanical chamber remodeling in zebrafish embryos—each without classical markers of disease. Collectively, these findings underscore how gene duplications enable nuanced regulation of the heart’s contractile apparatus