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The past decade has provided unprecedented insights into the molecular evolutionary pathways that have given rise to the present day diversity of vertebrates. Comparative genomic studies have repeatedly revealed that many key ecological traits, novel functional phenotypes, and even disease states are governed by genomic regions characterized by frequent mutations, duplications, or deletion events. However, the evolutionary origins and early diversification history of many of these regions remain poorly understood. My work focuses on providing a resolution to this history, focusing on the evolution of the vertebrate mobilome and a clustered gene family of innate immune receptors with putative links to the origin of the adaptive immune response. To accomplish this, I sequenced the genomes of Polypterus bichir and Lepisosteus osseus, two taxa that fill critical genomic sampling gaps for early diverging vertebrate lineages. Integrating these genomes into a comparative dataset of over 100 genomes that span all major ray-finned fish lineages, I investigated the effect of teleost genome duplication (TGD) on the diversification of the ray-finned fish mobilome. My findings reveal no substantial shift in mobilome composition following the TGD event, in line with a growing body of evidence that this historical ploidy event has not left a signature of a burst of molecular diversification and innovation across half of living vertebrates. I next expanded my taxonomic coverage to include all major vertebrate lineages to investigate the evolutionary origin of signal regulatory proteins (SIRPs) and their ligand CD47. In mammals, SIRPs are essential for regulating macrophage function and have become important targets for cancer therapy. These receptors also contain variable and joining exons and are hypothesized to have arisen in tetrapods out of a complex of innate immune receptor gene families that also gave rise to recombining T-cell receptors and antibody encoding Immunoglobulin domains. My work demonstrates this is not the case. Instead, SIRPs have evolutionary origins coincident with the origin of the adaptive immune response. In contrast, we find no evidence for an ancient origin of the CD47 ligand, which interacts with SIRPs. Instead, CD47 appears to have arisen at the beginning of amniote evolution, suggesting a decoupling of the evolutionary origins of this ligand and receptor pair. These findings provide a new perspective on the origins and diversification of innate immune receptor gene families and their relationship to the emergence of the adaptive immune system.
ABSTRACT
Culturally Responsive Teaching is a holistic pedagogical approach that appeals to the “whole child,” “whole school,” and “whole community” (Gay, 2001; Teschers, 2020); it is a multicultural practice that improves teaching and learning, promotes quality education, taps into the potential and uniqueness of students, and impacts learners intellectually, emotionally, kinesthetically, and physically (Gay, 2010; Widodo, 2019). This qualitative phenomenological case study examines the concepts and pedagogical practices of culturally responsive teaching through the shared experiences of educators and implementers of culturally responsive pedagogy to find out how effective those concepts and practices are in improving the academic outcomes of marginalized students (K-12) in urban classrooms. A purposive case sampling method (PCSM) and semi-structured interview were instrumental elements of the data collection process. A grounded theory method was used to both collect and analyze the data. Themes that emerged from the data of the interviews conducted with the participants were amalgamated to form four main themes for the study. Though this study may be limited by generalizability, it however provides answers to some lingering limitation questions of existing studies on culturally responsive practices. This study draws on and adds to the works of Geneva Gay on Culturally Responsive Pedagogy.
Keywords: holistic education, education equity, educational inequity, multicultural education, opportunity gap, culturally responsive pedagogy
Within the context of higher education, student conduct administration is drenched in risk, compliance with local and federal laws (Glick & Haug, 2020). In short, student conduct is a complex, and challenging functional area to work in, as administrators to balance educating students, protecting the campus community, and mitigating institutional risk (Miller & Sorochty, 2015; Lancaster & Waryold, 2008).
This qualitative, phenomenological study aimed to explore the lived professional experiences of student conduct administrators; to better understand their struggles and needs, as they would describe. Semi-structured interviews were used to capture depth in the shared experiences of ten participants and describe the meaning assigned to the phenomenon being explored.
The findings of this study were captured in 4 main themes: (1) Clashing with the Regime, which looks at SCAs challenges navigating political ecosystems within their respective institutions and states, (2) Encountering Turbulence, which captures common challenges SCAs experience while resolving cases (3) Nurtured by Leadership, which looks at the role of SCAs direct supervisor in fostering support and (4) Leaning on the Village, which captures the network of support SCAs receive outside of their direct supervisor.
This dissertation contains several new results concerning Moser-type optimal stopping problems. In the simplest case we consider sequence of independent uniformly distributed points X1, X2, · · · , Xn on the compact Riemannian manifold M and give algorithm for the calculation of Sn = maxτ≤nE[G(Xτ )]where G is a smooth function on M and τ is a random optimal stopping time. Description of the optimal τ depends on the structure of G near points of maximum. For different assumptions on this structure we calculate asymptotics of Sn.
The emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in December 2019 triggered a global pandemic, causing the urgent need for effective surveillance measures to combat its spread and monitor the evolution of new variants. Sequencing SARS-CoV-2 is an essential tool for surveilling the circulating and emerging variants. This thesis addresses key challenges and proposes advancements in sequencing SARS-CoV-2, focusing on both clinical and wastewater samples.The primary objective of this thesis is to optimize sequencing protocols for SARS-CoV-2 variants from clinical and wastewater samples, specifically targeting improved sequencing capabilities for low viral concentrations using the Oxford Nanopore Promethion platform. Through protocol modifications and refinements, we achieved notable enhancements in sequencing output metrics, such as amplicon amplification, sequencing depth, and the generation of high-quality consensus sequences. The second objective evaluates the performance of wastewater deconvolution software for identifying SARS-CoV-2 variants, employing a meticulous assessment approach with controlled mixtures of synthetic variants and amplicon-based sequencing. In this objective we highlight the effectiveness of Freyja, a widely utilized tool, in producing variant abundance calls closely aligned with expected ratios. In the third objective, we investigate factors contributing to ambiguous variant calls in next-generation sequencing data from two distinct platforms, shedding light on potential sources of variability in variant abundance estimation. Through comprehensive analysis, significant disparities in genome coverage and mutation profiles between platforms were identified, suggesting possible biases or variations in error rates. While Freyja demonstrates excellent performance with controlled datasets, challenges arise with real-world wastewater samples. Through these objectives, the thesis aims to offer insights into optimizing sequencing protocols, enhancing variant detection algorithms, and improving data reproducibility across different sequencing technologies. Ultimately, this research contributes to ongoing efforts in infectious disease surveillance by advancing our understanding of SARS-CoV-2 sequencing from diverse sample sources and providing valuable guidance for future research in viral pathogen sequencing.
This three-article format dissertation presents a comprehensive examination of the 2017 Community College Survey of Student Engagement (CCSSE), focusing on its measurement properties across diverse community college student populations. Study 1 centered on the validity of the internal structure of CCSSE. Exploratory and confirmatory factor analyses showed evidence to support an eight-factor model of student engagement. This model encompasses dimensions such as personal development, interactions with faculty and peers, and institutional support. This study marks a methodological and theoretical shift, advocating for a multidimensional perspective on student engagement in community college. Study 2 employed multi-group confirmatory factor analysis to examine the measurement invariance of the CCSSE across gender, age, race/ethnicity, and enrollment intensity. The results affirmed the CCSSE’s capacity to consistently measure engagement at configural, metric, scalar, and strict levels measurement invariance. This verification underlined the survey’s reliability in capturing authentic group differences. This study also uncovered lower engagement scores among men and part-time students. Study 3 explored the concurrent and predictive evidence of validity of the CCSSE, investigating how engagement indicators correlate with and predict key student success outcomes. It offered new insights into the complex effects of factors such as interaction with faculty and peers and advising services on academic outcomes.
This dissertation evaluates the fatigue response of a steam header designed to mirror the specifications of an ex-service unit, with a focus on optimizing material selection through a detailed analysis involving cost, performance, and durability. Beginning with a study comparing three different alloy choices, 2.25Cr-1Mo, 9Cr-1Mo-V, and IN740H, headers are developed and compared using the procedures outlined in ASME BPVC. The design of the headers follows that used in the original development, and their performance is evaluated in representative loading transients. Each of the designs is evaluated for their fatigue response using the finite element program Abaqus. The results demonstrate that cost savings would likely outweigh any performance benefit to the current system.
The second portion evaluates the material characteristics of 2.25Cr-1Mo following years of exposure to a harsh operating environment. Material specimens were machined from the ex-service unit and subjected to uniaxial testing at various temperatures. The process is used to establish the Chaboche NLKH hardening coefficients. The selection of the NLKH model was guided by its capability to capture the cyclic behavior of the material. The material results are used to compare the projected performance of the 2.25Cr-1Mo header found using readily available material acquired from virgin specimens and those found from the existing unit. The results demonstrate a markedly reduced strength in the service-exposed material, illustrating the effects of the material transformation that occurs over time. This study highlights the importance of operational wear on the projected performance of the header.
The final portion introduces an automated crack growth algorithm in combination with Abaqus to model the progression of a seam crack within a 2.25Cr-1Mo header. Traditional fatigue assessments consider the formation of surface cracks as the end of usability. However, it is well established that the existence of cracks in headers may be allowable, depending on several factors such as size, location, and material. Additional challenges exist in headers along the tube-header intersections, which suffer from non-uniform crack propagation stemming from the complex thermal-mechanical loading near the intersection. To address this issue, the present work develops an algorithm in Abaqus to use the seam crack capability and Paris law to efficiently perform iterative crack growth simulations. This approach captures the uneven growth response of the crack, providing more realistic service life estimations.
Scholars are particularly interested in understanding effective strategies to turn around business performance as businesses experience periods of decline. As the COVID-19 pandemic has revived the importance of better understanding effective turnaround strategies within organizations, additional research is needed to support businesses as they work to recapture or exceed pre-decline performance. This dissertation's research model suggests that operational and strategic turnaround responses have a relationship with firm performance. It is empirically tested using data collected from 98 top management team members across the United States regarding the operational and strategic turnaround responses implemented to combat the decline caused by COVID-19. The results show that strategic turnaround responses positively impacted firm performance. These findings have practical as well as theoretical implications that suggest the type of turnaround response needed in times of future global phenomena.
In the healthcare domain, the development of digital health technologies, including mobile applications, telehealth, wearables, and portals, have created new avenues to deliver patient care, track chronic illnesses, and distribute health information. Digital health technologies allow physicians and patients to interact outside of the traditional care settings; therefore, increasing access to care for disparate populations. Understanding the factors that impact a patient’s decision to adopt digital health technologies is essential to maximizing the Actual Use of digital health technologies and addressing health disparities. This research integrates the Health Belief Model (HBM) and Unified Theory of Acceptance and Use of Technology (UTAUT) to examine technology use behaviors specifically in the context of healthcare. This study evaluates three independent variables – intention to use, Perceived Health Benefit, and Social Influence to determine their impact on Actual Use of technology. This study also investigates how Trust in Technology and eHealth Literacy moderate the relationship between Actual Use of technology and its antecedents. Data from a sample of adults in the United States (N= 293) provides insights into the relationships of the proposed research model.
Family engagement with schools has been shown to be a predictor of student success (Powell et at., 2010) and federal statute supports school/ family relationships through the Family Engagement in Education Act. For students with disabilities (SWD), family engagement may be even more critical. Unfortunately, data has suggested that family engagement may be limited due to barriers families of SWD may face (Van Haren & Fiedler, 2008). Teacher invitation, teacher beliefs about family involvement and quality of communication are factors related to family engagement. The purpose of this study was to investigate an in-service teacher's use of a step-by-step strategy during family/ teacher conferences to increase family engagement during the conference, improve quality teacher communication and positively impact teacher beliefs on family involvement. The step-by-step conferencing strategy was called PIQUE and was developed through a review of prior research and feedback from experts in the field. This case study used both quantitative and qualitative methods to determine the effectiveness of the PIQUE strategy. Within an AB single-case design, I noted an increase in the 5-second intervals of the family speaking during the conference from baseline to post-intervention phase. This increase was immediate and demonstrated an accelerating trend. The teacher and parent completed surveys and interviews, which were analyzed thematically alongside descriptive and inferential field notes recorded by the researcher. Through this analysis, two primary themes were identified as Misunderstanding Communication as Equal to Engagement and Bias as a Barrier to Engagement. A secondary theme of Lack of Confidence When Engaging with Families was also identified. Triangulation was achieved across quantitative and qualitative data sources. Conclusions point to an increase in equity of power during conferences and positive change in teacher beliefs about family involvement and engagement after the implementation of the intervention. A conclusion that PIQUE implementation led to these changes should be interpreted with caution due to the threats to internal and external validity of case studies. The study concluded with implications for practice, limitations and suggestions for future research.
