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Assessing Targeted and Enhanced Pediatric HIV Identification Efforts in Tanzania
Get PDFTremendous progress has been made on tackling the global HIV epidemic. However, amidst this overall success, challenges remain with reaching undiagnosed children living with HIV (CLHIV) with testing and treatment services. Targeted efforts to close the critical gaps rely on a solid understanding of the underlying pediatric burden of HIV at a national- and sub-national level. As the world has moved away from the use of gold-standard population-based surveys for the collection of data on HIV prevalence among children there has been a growing sense of uncertainty around modelling estimates. To help address this concern, in 2023-2024, Tanzania implemented a set of Targeted and Enhanced Pediatric Identification (TEPI) activities in three regions of the country that aimed to identify as many new CLHIV as possible in those regions while generating scalable best practices and improving the understanding of the pediatric burden of HIV in Tanzania. This dissertation contributed to the assessment of the TEPI activities by employing a mixed-methods approach to considering quantitative and qualitative evidence generated from implementation. Descriptive and in-depth data analyses using the synthetic control method were conducted to assess how TEPI activities impacted pediatric identification in the three implementation regions. A structured approach based on the rigorous and accelerated data reduction (RADaR) technique was utilized to synthesize qualitative evidence throughout implementation and identify key lessons learned and scalable best practices. Overall, the TEPI activities were found to have contributed to the identification of approximately 250 more CLHIV than might otherwise have been expected across the three regions. A number of scalable best practices were also identified related to improving and enhancing routine pediatric index testing and early infant diagnosis activities, as well as potential new interventions to pursue such as implementing HIV testing at orphanages. The dissertation also proposes a plan for change focused the translation of key findings to improve the identification of new CLHIV more widely across Tanzania. This plan for change also lays out a plan for sharing findings more broadly outside of Tanzania and for utilizing the findings to improve pediatric HIV modelling estimates.Doctor of Public Healt
A Meta-Analysis of Testing Effects with Free Recall
Get PDFRetrieval practice improves memory more than restudying— the testing effect (TE). While most studies have concentrated on the direct TE (improved memory for tested material), the designs used often fail to account for the influence of forward TEs (improved memory for material learned after a test). In many studies of “the testing effect,” both effects are at play. Mulligan et al. (2022) reported an absence of a direct TE when using free recall as retrieval practice and rather found evidence of forward TEs. Such findings warrant a new meta-analysis on TEs with free recall, that examines direct and forward TEs and the factors that moderate them. This meta-analysis does so by distinguishing between studies capable of isolating the direct TE and those that are susceptible to both direct and forward TEs. Significant differences between these categories of studies underscore the importance of differentiating between direct and forward TEs.Master of Art
FORWARD-IN-TIME SIMULATIONS IN POPULATION GENETICS: PROMISES AND PITFALLS
Get PDFForward-in-time simulations are a commonly used tool in population genetics, offering the ability to realize a large range of evolutionary phenomena such as selection, demography, spatial considerations. However, they often require large computational resources, rendering simulations of full populations of genomes nearly intractable. A common approximation used by researchers to reduce the computational burden of these simulations involved scaling the size of the simulated population down by a specific factor, while scaling other parameters such as the mutation rate and selection coefficients of simulated mutations. However, it is not fully understood how this approximation may bias important outcomes. This thesis discusses the biases introduced to outcomes of forward-in-time simulations through a systematic analysis of such biases across a wide range of evolutionary and demographic scenarios using machine learning and statistical techniques, and the effect of sample size in simulation replicates on the estimates of bias.Furthermore, this thesis introduces an application of forward-in-time population genetics simulations in an evolutionary rescue model of cancer which includes two sequential treatments applied to a simulated population of cancer cells undergoing expansion and acquiring mutations conferring resistance to the applied treatments. We show that the timing of the switching from the first to the second treatment has important implications for the likelihood of success for the simulated therapy protocol, and which parameters may impact this optimal timing. We also compare this sequential protocol to a combination therapy approach and elucidate model assumptions under which optimally timed sequential therapy may outperform combination therapy. Finally, we show that these conclusions hold even when the genetic architecture of resistance changes. The results discussed in this thesis have important implications for researchers in the field of population genetics who are looking to use population size rescaling to decrease the computational cost of forward-in-time simulations and provide a basic framework for the utility of these simulations to model cancer evolutionary rescue and optimal treatment timing.Doctor of Philosoph
PERFORMANCE OF A DISCRETIONARY CHILD PROTECTION SYSTEM REPORTING POLICY FOR INFANTS WITH PRENATAL SUBSTANCE EXPOSURE
Get PDFThe child protection system (CPS) serves as a primary responder to infants with prenatal substance exposure (IPSE). While CPS plays an important role in protecting children, policies allowing discretion in reporting offer the potential to strategically deploy CPS intervention. However, implementation and effectiveness of discretionary reporting may be affected by institutional policies and inconsistencies in provider behavior. The discretionary reporting policy in California does not require safety or service planning for IPSE who are not reported. While substance exposure is a known risk factor for CPS intervention, early connections to services improve child and family outcomes.The objective of this dissertation is to study the performance of a discretionary reporting policy by: (1) examining patterns in reporting using descriptive statistics and multilevel modeling; and (2) analyzing 5-year risk of CPS involvement by documented IPSE exposure status, among those not reported to CPS in the first two weeks.We used a birth cohort dataset of linked administrative records from 2018-2023. We specified multi-level logistic models clustered by hospital to identify predictors of CPS reporting, and multivariable Poisson and Cox proportional hazards regression to examine 5-year incidence of CPS involvement. Fewer than 3% of a sample of California births had diagnostic evidence of substance exposure. Hospitals explained 24% of the variance in CPS reporting. We found evidence of interactions between individual- and hospital-level demographic categorizations. Within hospitals with mostly privately insured maternal patients, births covered by public health insurance were nearly twice as likely to be reported than births covered by private insurance. Among a sample of not-reported births, documentation of substance exposure was associated with an increased risk of both reporting of maltreatment harm and having any maltreatment allegation substantiated by CPS over five years. This association persisted in models disaggregated by substance exposure type; those with only cannabis exposure were two times as likely to experience either CPS outcome in adjusted models. Results of our examination into the performance of a discretionary reporting policy in a single state context highlight inconsistencies in hospital reporting of IPSE and potential failures to adequately serve IPSE at increased risk of later CPS involvement.Doctor of Philosoph
SENSITIVE TO A SOCIAL WORLD: INTERACTIONS BETWEEN NEURAL FUNCTION AND SOCIAL NETWORKS ACROSS ADOLESCENCE
Get PDFAdolescent development is profoundly impacted by both dynamic social environments and neurobiological changes that heighten the salience of social stimuli. However, methodological constraints often limit the peer network features that can be incorporated into developmental neuroscience research. This integrative dissertation utilizes longitudinal social network, neuroimaging, and self-report data to expand our understanding of the interactions between adolescents’ social environments and their neural sensitivity to salient social information across early adolescence. Study 1 shows that changes in the size of adolescents’ friendship networks are associated with subsequent increases in neural reward sensitivity throughout early adolescence. Study 2 suggests that neural sensitivity to rewards, which may reflect adolescents’ desire to affiliate with peers, predicts changes in loneliness differentially on whether they gain new friends over time. Study 3 indicates that heightened neural sensitivity to broader features of peer environments, such as the low social status of peers, can heighten the risks of depressive symptoms for adolescents who are unpopular themselves. Collectively, these three studies highlight how dynamic social environments can be related to longitudinal changes in adolescents’ neural function and socioemotional outcomes. Taken together, this integrative dissertation demonstrates that incorporating measures from social network analysis can broaden our understanding of the complex interplay between adolescents’ individual neural function and their dynamic social environments.Doctor of Philosoph
Which Unanimities Ought We Preserve?
Get PDFPhilosophers working on group credences are centrally interested in the question of how groups’ credences are related to the credences of their members. The contender answers are typically represented as different credence-aggregation functions, or functions from many credence functions to one credence function. These credence-aggregation functions are generally evaluated in terms of their formal features, and one relevant sort of formal feature is preserving a unanimity. A credence-aggregation function preserves unanimous F’s iff whenever every inputted credence function is F, the outputted credence function is F. A recent paper by Richard Pettigrew depends on the principle that we ought to preserve only unanimous judgments. This thesis evaluates that principle.Master of Art
NAVIGATING THE TRIPLE BURDEN: UNDERSTANDING PREGNANCY, HIV, AND MENTAL WELL-BEING AMONG ADOLESCENT GIRLS AND YOUNG WOMEN IN ZAMBIA
Get PDFIntroduction: Adolescent girls and young women (AGYW) in Zambia face a triple burden of mental health challenges, pregnancy, and the complexities of living with or being at risk for HIV. High rates of anxiety and depression are compounded by stigma, socio-economic hardship, and limited mental health services. AGYW who become mothers often encounter health system constraints, financial insecurity, and competing responsibilities that hinder postnatal care (PNC) engagement. While social support and self-efficacy are recognized protective factors, their influence across age and HIV status remains underexplored. This dissertation examines the intersection of social support, self-efficacy, mental health, and maternal service engagement among AGYW in Zambia, focusing on mental health outcomes and experiences with facility-based delivery, breastfeeding, and PNC.Methods: This cross-sectional mixed-methods study draws on two datasets. Quantitative baseline data (N=1123) from the SHIELD/IWC trial were analyzed using logistic regression to assess associations between social support, self-efficacy, and mental health (anxiety and depression), stratified by HIV status and age group (10–15, 16–20, 21–25). Additionally, in a nested mixed-methods study, survey data on postnatal distress, PNC, and breastfeeding were collected from 40 AGYW. Qualitative data included in-depth interviews with these same 40 postpartum AGYW and focus group discussions with healthcare providers and caregivers.Results: Family support was associated with reduced anxiety, especially among AGYW aged 16–20, while friend support was linked to increased anxiety, particularly among AGYW living with HIV and those aged 21–25. Self-efficacy was not significantly associated with mental health overall but predicted higher depression among AGYW aged 10–15 and those living without HIV. Postnatal distress was common, shaped by concerns over newborn care, finances, and personal health. Despite all AGYW attending at least one PNC visit, barriers such as long waits, vaccine shortages, and stigma discouraged continued care. Social support aided PNC attendance and breastfeeding, though food insecurity and transportation challenges disrupted both.Conclusion: Findings highlight the interconnected burdens of mental health, maternal health, and HIV among AGYW. Addressing stigma, socio-economic disparities, and health system barriers is vital for improving outcomes. Future research should explore longitudinal trends and interventions to enhance resilience and youth-friendly care.Doctor of Philosoph
Historical And Contemporary Indicators of Structural Racism and Pedestrian Injury Rates In Chicago: A Spatiotemporal Analysis
Get PDFTransportation injuries and fatalities are a significant public health problem across the United States (U.S.). Black and Brown communities and those residing in low-income areas experience higher rates of adverse outcomes due to motor vehicle crashes, especially as pedestrians, due in part to unsafe roadway infrastructure (e.g., high-speed roads). Research to address these disparities has focused on individual-based risk factors rather than root causes that facilitate unsafe roadway environments. This dissertation applied an equity lens using interdisciplinary research methods to measure the impact of structural racism on transportation safety. Aim 1A characterized two place-based indicators of structural racism in Chicago, Illinois using cross-sectional 1940s historical redlining and longitudinal racial-economic residential segregation from 2000 to 2019 for Non-Hispanic Black and Hispanic populations. Aim 1B examined the spatiotemporal nature of historical and contemporary indicators of structural racism by creating an index combining the intersection of 1940s historical redlining grades and racial-economic segregation from 2000-2019 to define neighborhood trajectories. Data were obtained from the Mapping Inequality Project from the University of Richmond and the U.S. Census at the census tract level to create neighborhood context from 1940s and 2000 to 2019. The spatiotemporal patterns of historical redlining and contemporary racial-economic segregation suggested substantial stability, with many neighborhoods remaining in their historical classification. Neighborhoods with greater impacts of historical housing discrimination had more variability in their neighborhood trajectories from 2000 to 2019.Aim 2 investigated the association between cross-sectional 1940s historical redlining, neighborhood trajectories (Aim 1B), and pedestrian-vehicle crashes. Data from Aim 1 were combined with police-reported crash data at the census tract level. Conditional autoregressive Poisson models were used to estimate incidence rate ratios that quantified the associations of pedestrian crash rates (per 10,000 residential population), historical redlining, and neighborhood trajectories. We observed an association between historical redlining and the rate of pedestrian- crashes and even stronger associations when examining neighborhood trajectories. Stable disadvantage trajectories had a rate of pedestrian crashes twice as high as neighborhoods with Stable Advantage trajectories. Population-level research on historical and contemporary measures of structural racism and their lasting impacts on pedestrian crashes is needed to further transportation research.Doctor of Philosoph
The Language of Contemporary Social Protests in Latin America: Mnemo-Critical Artifacts and Their Role in Shaping Marginalized Collective Memory and National Identity During the 2021 Colombian Social Outburst
Get PDFMy research, grounded in the Colombian context, explores the relationship between memory, collective identity, and the visual language of social protest. Focusing on aesthetic-political expressions that emerged during the 2021 Social Outburst, I argue that these mobilizations center on the memory of a state crime from the early 2000s, commonly known as the falsos positivos (false positives). The unresolved and secretly ongoing process of false positivization functions as an ideological framework through which marginalized communities in the second decade of the century come to interpret themselves as a collective identity potentially targeted by state violence—that is, as “living false positives.”This subaltern identity is expressed through various mnemo-critical artifacts. I define mnemo-critics as epistemological and de-ideologizing artifacts through which protesters symbolically interpret their multidimensionally violent reality, challenging hegemonic narratives rooted in the exclusion of the “Other”—the so-called “non-Colombian.”Rejecting the roles traditionally assigned to marginalized populations by the state—such as the “internal enemy” or the passive “victim”—these protests construct an identity that emerges from systemic violence and resists entrenched exclusionary dualisms. Rather than reviving the failed tactics of armed revolutionary movements, this identity seeks transformation within the framework of democratic principles. The vision of an inclusive Colombian national identity—symbolically inscribed on the walls during the Social Outburst—ultimately culminated in the historic election of the country’s first leftist government one year later.Throughout this work, I examine a range of mnemo-critical artifacts and their role in the narrative and existential struggles of those who perceive themselves as “falsely alive.” I analyze how these mnemo-critics temporarily grant material presence to a precarious identity under the pressures of capitalist politics, question the illusion of hegemonic permanence, and articulate a humanistic political alternative.Doctor of Philosoph
Populism in America: Anti-Elitism and Anti-Pluralism in the United States
Get PDFPopulism has become a defining force in the politics of democratic nations the world over in the early 21st century, and the United States is no exception. I define populism as the notion that the government has sold out the ``real” people of a nation in favor of some ``other” group. I define populist rhetoric as that which is both anti-elite -- targeting the government -- and anti-plural -- targeting some ``other.” I further identify three distinct strains of populist rhetoric – governmental, economic, and social – based on the group being assailed. I consider the place and prominence of populism in American politics across the nation’s history. In the late 19th century, both parties used anti-elite and anti-plural cues strategically. In most cases, the party out of power used more populist rhetoric in its efforts to disparage its rival. The party in power used much more populist rhetoric in moments of national crisis. Populism remained a feature of American politics across the 20th century. In the early 21st century, changing political cleavages and a global recession left an immense audience receptive to populist politics. I assess the ways in which Democratic and Republican Senate candidates across eight states used populist rhetoric in their primary campaign messaging in 2022. I find that Republicans used far more social populist rhetoric than Democrats, and that Democrats employed far more economic populist messaging than Republicans. I also find significant variation in how candidates of the same party used populist cues. Finally, I use survey data to consider whether primary voters might use candidates’ populist rhetoric as a heuristic. In primaries where populist rhetoric was a prominent part of the information environment and one candidate used substantially more populist messaging than the others, respondents with more populist views were substantively and significantly more likely to support the most populist candidate. This dissertation sheds light on a timely subject of superlative importance to contemporary American politics.Doctor of Philosoph