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Advancements in our Understanding of Enteric Formation and Function
No full textEstablishing the Enteric nervous system (ENS) relies heavily upon migration, colonization, and proper neural diversification to ensure a functional digestive tract. This dissertation investigates the role of Sox10 in ENS development and its potential implications for ENS function. Single-cell RNA sequencing during early ENS development reveals distinct neuronal trajectories and upregulation of Hox gene regulatory network activity as cells transition toward neuronal states. Differential expression analysis identifies significant downregulation of Hoxa6 within Branch C, indicating the involvement of Hox genes in neuronal diversification. Comparisons between Sox10+/+ and Sox10Dom/+ lineages highlight differences in the cellular landscape, underscoring Sox10's regulatory role in ENS development. Additionally, introducing the Sox10 MS mouse model aims to enhance cost-effectiveness and efficiency in Sox10-related studies. This model detects spontaneous calcium activity at the wavefront of migrating enteric progenitors and increased calcium activity in the enteric glia of Sox10Dom/+ offspring, suggesting Sox10's involvement in calcium signaling within the mature ENS. The data presented in this thesis serve as a foundation for further exploration of ENS development at the transcriptomic level and expand the available tools for research in enteric studies
Computational Modeling of the Hummingbird Escape Maneuver
No full textHummingbirds are perhaps the most agile flyers in nature. Studying the underlying physics of hummingbird flight may provide inspiration for developing highly maneuverable micro aerial vehicles (MAVs). In this work, we have developed a high-fidelity computational fluid dynamics (CFD) model to analyze the aerodynamics and flight mechanics of the hummingbird escape maneuver, in which hovering hummingbirds were startled and perform a rapid (less than 0.2 seconds) maneuver to back away from a perceived looming threat on the front side. Several novel mechanisms were discovered in this study. First, we found evidence across several species that hummingbirds use the inertial forces of their wings to increase their body rotational acceleration. For example, at pronation when the wings switch from upstroke to downstroke, the wing inertial forces create a torque that helps pitch up the bird’s body to move the head away from the threat. Such inertial steering effects are accompanied by aerodynamic steering of the wings to generate a fast rotational speed to improve maneuverability. Second, we studied the actuation of the wings during the escape maneuver by considering the muscle input at the shoulder joint in addition to the wings’ aerodynamic and inertial outputs. Contrary to previous thoughts that wing pitch rotation is primarily passive due to the wings’ own inertia, our results show that significant power input was required to pitch up the wings during downstroke to enhance aerodynamic force production. As a result, an active mechanism is required to pitch the wings for maximal force output. Third, we found that pitch, roll, and yaw rotations of the bird body may overlap with one another, which may create a nonlinear, inertial coupling effect that hummingbirds utilize as a passive mechanism for flight control, e.g., to stabilize body pitching during the maneuver. These novel findings have significantly improved our understanding of hummingbirds’ great maneuverability and may be useful for the future development of bioinspired MAVs
Empowering Minds: Cultivating Critical Thinking in the Age of AI
No full textLeadership and Learning in Organizations capstone projectPartnering with the Tommy & Victoria Baker School of Business (BSB) within the Citadel College, this study aimed to examine and evaluate how the curriculum, cadets, and faculty of the BSB develop and assess critical thinking skills through evaluation of class content, syllabi, and assessments within the business school while considering the transformative potential of emerging AI tools. The guiding questions used to explore this inquiry included: In what ways are critical thinking skills integrated and emphasized within The Citadel’s Tommy & Victoria Baker School of Business? Particularly in relation to evolving learning methodologies and the emerging potential of Artificial Intelligence (AI)? To what extent can BSB measure the success of critical thinking assessments within the curriculum? In what ways are AI tools being utilized by students throughout their coursework?
The study employed a mixed methods approach, combining qualitative and quantitative research methods including career center interviews, surveys of current cadets and faculty, along with analysis of course syllabi and teaching materials to identify how critical thinking is integrated into the BSB experience. Findings included the existence of a potential for more profound critical thinking integration into coursework and assessments. AI is viewed with great apprehension by faculty who report limited knowledge of how it can support critical thinking skill development or training of how to utilize it effectively, whereas cadet results were in contrast to this, exposing a divergence in views between faculty and cadets
Data Quality-Aware Graph Machine Learning
No full textGraph-structured data is ubiquitous in real-world applications (e.g., social networks, infrastructure, biomedical) and Graph Machine Learning (GML) has become a prominent method for handling such data. However, despite GML’s remarkable achievements, its reliance on node features makes it susceptible to conventional data quality issues, and the additional consideration of graph topology adds novel complexity. Inspired by these challenges, my research in this dissertation focuses on data-quality-aware graph machine learning, systematically examining issues related to topology, imbalance, bias, and limited data issues in graph data. This includes proposing data/model-centric solutions to handle them and applying my proposed data issue solutions for real-world applications, such as de-noising unrelated interactions in personalization learning for recommender systems, overcoming the inherent class-imbalance issue in computer-aided drug discovery, mitigating hallucination bias in multi-document question answering, and boosting limited training data for graph generations. Lastly, to further advance the field of data quality-aware GML, I have outlined multiple future directions to make data quality-aware GML more inclusive, intelligent, and trustworthy
Demonic Possibilities: Uncertain Futures and the Creation of Existences Nonetheless
No full textAudre Lorde wrote A Litany for Survival where she posited that “it is better to speak remembering we were never meant to survive” and that in the end what we are seeking is “a now that can breed futures”. The ability to imagine possible futures requires us to find existences in the present that allow for hope and joy. Still, many come to be their present selves despite current and past worlds that were designed against them. This project investigates the various ways of being constructed by people who have found ways to thrive in a world that denies their existence through laws, religions, social policies, gender and sexual discrimination, and racialized violence. Through an analysis that begins in languages, stories, and narratives, this project focuses on the world-making of Black, Queer, and (also) Indigenous people. More, this research works to address problems in the language of marginality for these groups. It offers the terms liminal people and the demonic to better encapsulate Black, Queer, and Indigenous identity and agency. This project then explores Barry Jenkins artistic use of moonlight in the film Moonlight to transition toward a study of identity, locality, and place-making as a means for survival and joy. In the midst of examining these created worlds, the role of nothingness emerges as a fertile ground of possibilities. This dissertation ends by considering the dysregulating and demonic force that liminal peoples’ fluidity offers in opposition to the restrictive and oppressive systems created by dominant groups
School as a Safe Space: The Impact of Exposure to Gun Violence on the Social-Emotional Learning and Well-Being of Black Boys in Grades 7-12 at U Prep
No full textLeadership and Learning in Organizations capstone projectThis quality improvement project sought to understand the impact that exposure to gun violence had on the social-emotional learning and well-being of Black boys in grades 7-12 at the University Preparatory Charter School for Young Men (U Prep). U Prep is a charter school located in Rochester, NY, founded to provide safe and stimulating educational experiences for Black youth in the Rochester area and to change the narrative for Black males in urban neighborhoods. While the City of Rochester continues to see increased gun violence, students at U Prep are continuously exposed to gun violence in various forms, including community gun violence. U Prep aims to better understand how exposure to gun violence impacts its student body while also providing more resources to support students exposed to gun violence as well as the teachers working at U Prep. This project explored the impacts of gun violence on youth as it relates to students’ social-emotional well-being at U Prep. We examined the intersection between community, school, and well-being using social-ecological and trauma theories to establish recommendations for U Prep to support students exposed to gun violence
Magmatic Architecture and Processes in a Supereruption-scale System: The Crystal-Rich Ora Ignimbrite (Permian, Northern Italy)
No full textThe Ora Ignimbrite (~275 Ma) is a crystal-rich (~40%), heterogeneous, supereruption-sized (~1,300 km3) rhyolite in northern Italy and the final eruptive product of the Athesian Volcanic Group (289 - 274 Ma), the largest Permian volcanic district in Europe. We investigate magma storage conditions and the dynamic processes that occur in large silicic systems by studying geochemical and petrological characteristics of juvenile material from the Ora Ignimbrite. Two key vitrophyre outcrops contain well-preserved, glass-bearing, crystal-rich (20-50%) and crystal-poor (<20%) fiamme. Textural analysis of these fiamme reveals four types: coarse-grained crystal-rich (VCCR) and fine-grained crystal-poor (I-FCP) intracaldera fiamme and coarse-grained crystal-rich (CCR) and fine-grained crystal-poor (O-FCP) outflow fiamme. Differences in fiamma textures, mineral rim compositions, and glass trace-element compositions indicate that at least two separate magma reservoirs, each containing multiple crystal-rich magma bodies, erupted to form the Ora Ignimbrite. High-precision40Ar/39Ar sanidine ages suggest that the eruption of each reservoir may have been separated in time. Discrete and tightly-clustered crystal-rich (VCCR & CCR) fiamma glass trace-element populations support the existence of multiple magma bodies in the Ora system. Plagioclase and sanidine rim compositions plot in distinct domains, reproducing clusters observed in glass trace-element compositions, and euhedral rims suggest these crystals recorded the final melt compositions of five separate magma bodies. Three CCR populations can also be differentiated by plagioclase traverse compositions, bulk fiamma compositions, and textural features unique to each population; rhyolite-MELTS quartz and two feldspar storage pressures suggest the CCR magmas are stored at slightly different depths, from 115-160 MPa. VCCR magmas appear to be stored at similar depths (135-150 MPa). High crystal contents (VCCR: 40-50%; CCR: 20-40%), large crystals (max grain size: VCCR: 4-10 mm; CCR: 3-4 mm), and interlocking growth textures in crystal-rich (VCCR & CCR) fiamme indicate that these magmas contained parcels of disaggregated mush. Complex feldspar textures with Ba-enriched zones surrounding resorbed cores suggest that silicic recharge facilitated mush entrainment into the crystal-rich magmas. Mingled crystal-poor fiamme with high- and low-silica rhyolite glasses provide further evidence for silicic recharge in the Ora System
Self-Care for Black Women Clergy: A Pathway for Awakening The Soul to Becoming Well
No full textDivinity School Doctor of Ministry in Integrative Chaplaincy Final ProjectsThe shout for women’s rights, equality, and the desire to be visible and cared for has been a clarion call for centuries and Black women continue to live in the tension of this shout-both in how we exemplify our faith and in how we have been shaped to show up in the world. This paper will spotlight the systematic devaluation of Black women clergy and patriarchy in the AME church tradition. Research indicates theological spaces and practices are often guided by gender domination against Black women. In contrast, I argue that engagement with the principles of womanist theology and the cultural resonance of music will reconstruct the patriarchal gaze of domination, which opposes the fullness of the work of Christian ministry. I reimagine the church as a space where Black women clergy awaken their souls to expand thought on mental wellness and self-care to thrive as servant-leaders in the church. In this way, my discussion creates a transformative vision for inclusion as a faithful response to human flourishing
Local College Availability and College Outcomes
No full textGeographic college access is inequitable in the United States, yet few studies examine how limited college options constrain students’ college choices and influence attainment. The first chapter of the dissertation examines the relationship between local college availability and regional degree attainment rates. The second and third chapters of the dissertation explore how Latinx college outcomes are affected by college accessibility in Texas, a state with a sizeable Latinx population and diverse geographies. These studies rely on rich administrative data sources, including student-level data from the Texas Educational Research Center (ERC) and college-level data from the Postsecondary Participants System (PEPS). These data sources are used to explore the geographic accessibility of colleges, to describe variation in accessibility by Latinx ethnicity, and to describe how local college availability affects Latinx students' college enrollment and degree attainment patterns. Finally, this data is used to examine how increases in local postsecondary availability via new college site location openings affect the outcomes of Latinx students living near these institutions. In the first chapter of the dissertation, I find that counties with greater local college availability have higher regional educational attainment rates. In the second and third chapters of the dissertation, I find that Latinx students in Texas are more likely to live in education deserts and that living in these regions is negatively related to the outcomes of Latinx students; similar relationships are not observed for non-Latinx students. Finally, I find that Latinx students living in regions where a new postsecondary site is established are more likely to enroll in four-year colleges and that the establishment of four-year college locations drives these enrollment increases. The combined studies can help researchers and policymakers better understand Latinx students’ college enrollment and completion needs. Understanding these relationships is paramount as Latinx populations continue to rise and increasingly settle in geographically isolated areas with limited postsecondary opportunities
Three Essays in Double/debiased Machine Learning and High-dimensional Econometrics
No full textIn today’s big data world, we have witnessed rapidly increasing popularity of machine learning methods in empirical studies, such as random forests, lasso, post-lasso, elastic nets, ridge, deep neural networks, and boosted trees among others. The objective of this paper is motivated by recently increasing demand for Dou- ble/debiased Machine Learning (DML) methods in empirical research