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Nuclear Testing Is Nuclear Use: The Regime of Testing in US Nuclear Imperialism in the Pacific Ocean
No full textNuclear test sites worldwide have endured the health, environmental, and political consequences from the more than 2,000 nuclear weapons ever detonated. However, inadequate concepts have limited mainstream International Relations (IR) to consider only two detonations as “nuclear use,” namely during the atomic bombings of Hiroshima and Nagasaki, while relegating thousands of detonations that occurred at the test sites as part of the global “nuclear nonuse.” Contrary to the assumption that nuclear weapons have not been used after 1945, this dissertation argues that nuclear testing was the key mechanism through which nuclear weapons were used. I ask how nuclear detonations became practiced and enunciated as “testing,” which has effectively dismissed the level of violence involved. To capture this becoming, I propose the theoretical framework of the “regime of testing” by which I mean the political relations that enable nuclear detonations to take place as “tests” and simultaneously downplay them as “nothing more than some tests.” To demonstrate the framework and argument, this dissertation focuses on US nuclear tests in the Pacific (1946-62) and uses a mix of qualitative methods to interpret archival and interview materials. I show that the regime of testing parasitized existing imperial relations between the US and the Marshall Islands to transform lived atolls into nuclear laboratories, violent detonations into controlled scientific experiments and spectacular shows, and the systematic production of destruction into moments of learning. I show that the regime of testing persisted even after the 1963 Partial Test Ban Treaty as the US government, military, and scientists experimented on how to deal with the effects of nuclear detonations by subjecting Marshallese bodies and the environment to further research and testing. This dissertation remedies IR’s systematic omission of thousands of nuclear detonations in testing from serious analysis, leading to more empirically rigorous and conceptually adequate understandings of the role of nuclear weapons in global politics
Computational fluid dynamics based models of gastric digestion in health and disease
No full textThe stomach lies at the center of multiple modern healthcare challenges, including nutrition, obesity, diabetes, and drug delivery, among others. Disorders of the stomach, such as gastroparesis and functional dyspepsia, still do not have a cure, and bariatric surgeries are being prescribed to an ever-increasing number of people. Meanwhile, the oral route remains the most common means of drug delivery, and novel functional foods are a burgeoning category in the food industry.
In vivo methods, aside from being resource intensive, only provide limited access to the stomach, and in vitro methods fail to emulate the complex biomechanics of the stomach. Computational approaches are well-suited to such problems as they are relatively cost-effective and provide unique and insightful data unavailable from other approaches. Though successfully used in cardiovascular flows for almost half a century, their use in stomach biomechanics lags cardiology by several decades. The stomach physiology also poses additional computational challenges, such as the need for long integration times (since digestion lasts over an hour) and vast variations in the properties of its contents.
In this study, we develop high-fidelity in silico (i.e., computational) models of the stomach that capture the fluid mechanics of the contents alongside the physiological functions. An imaging data-based anatomically realistic stomach model is constructed, featuring the pylorus and the duodenum as well as the contraction of the stomach walls.
The model is first used to study the hydrolysis of a liquid meal, revealing that motility disorders can not only slow down the gastric emptying rate but also reduce the rate of hydrolysis of liquid meals. Following this, the efficacy of pyloric intervention procedures towards different gastroparesis phenotypes is investigated, showing that the surgery is effective only when the stomach retains some of its gastric tone. The third study focuses on simulating the phenomenon of duodenogastric reflux to analyze the role of contributing factors and shows a possible mechanism by which the reflux can reach the esophagus. Finally, a first-of-its-kind model that incorporates solid foods into the stomach is presented, which enables us to gather novel data on the trituration of solid meals
Applications of Metal-Organic Frameworks in Charge Transfer Processes and Energy Storage Technologies
No full textThe growing energy demand and shifts to renewable energy necessitate the parallel development of high-capacity energy storage devices. Lithium-sulfur (Li-S) batteries offer a promising solution, utilizing materials with high-capacity and of low-cost. However, electron conductivity, polysulfide shuttle effects, and increased cell polarization at low temperatures remain major challenges. Metal-Organic Frameworks (MOF)s are 3D crystalline materials that offer diverse and highly tunable design spaces in structure and functionality that can meet a diverse range of application needs. Particularly, large pores and high surface areas offer opportunities for physical and chemical adsorption of polysulfides in lithium sulfur batteries to improve capacity.
In Chapter 2, we will observe the interactions between polysulfides and open sites of Zr-based MOF nodes. We first use density functional theory (DFT) to evaluate the binding affinity of Li2Sx (x = 2, 4, 6, 8) to single open site Zr-nodes and demonstrate increased binding strength as open sites are lithiated. We experimentally evaluate polysulfide binding through synthesizing and lithiating zirconium polyoxometalates and demonstrate the change in the speciation of interacting polysulfides due to the increased availability of lithium. Following this work, we demonstrate the effects of chemical binding at Zr open sites with lithium thiophosphate tethers. Li-S batteries containing MOFs with tethering sites demonstrate improved capacity, particularly at low temperature cycling and evaluation of 7Li nuclear magnetic resonance (NMR) spectra suggests chemical attachment serves to disrupt clustering effects that limit sulfur utilization.
Chapter 3 will discuss our work towards the broader understanding of polysulfide speciation and clustering that occurs under varied electrolyte conditions and temperature. NMR studies demonstrate the effects 1,3-dioxolane (DOL) has on interacting with counter-anions and increasing polysulfide clustering effects with temperature. Changes in the vibrational modes of lithium binding dimethoxy ethane (DME) are discussed through difference spectra IR measurements, and evidence of temperature dependent clustering is observed in UV-Vis and Raman spectroscopies.
Chapter 4 discusses the room temperature synthesis of PbS@MIL-88b(Fe), a QD@MOF hybrid material that has demonstrated the potential for charge transfer applications through changes in optical absorbance lifetimes and quenching of emission. We evaluate the synthetic conditions that affect sample crystallinity and component dispersion through diffraction and electron microscopy techniques
EARLY LIFE DRIVERS AND DEVELOPMENT OF ADHD IN THE BOSTON BIRTH COHORT: APPLICATION OF MULTIDIMENSIONAL RISK FACTOR ANALYSIS, LIPIDOMICS, AND MEDIATION ANALYSIS
No full textAttention-Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder affecting approximately 7 million children and adolescents in the U.S., according to the 2022 National Survey of Child Health. Despite its prevalence, the etiology of ADHD remains incompletely understood, underscoring the urgent need to identify early-life determinants and inform primary prevention strategies. This dissertation examined the additive and interactive effects of multi-dimensional early life risk factors on childhood ADHD, as well as potential underlying biological pathways, using data from the Boston Birth Cohort (BBC) - a racially, ethnically, and socioeconomically disadvantaged population at elevated risk for ADHD. Specifically, this dissertation addressed three aims:
Aim 1 examined the combined impact of multilevel, across-domain risk factors on childhood ADHD risk in 2,265 mother-child dyads (591 ADHD, 1674 neurotypical) using a novel multilevel analytical approach. Six risk factors - maternal nativity, race/ethnicity, smoking, pregnancy stress, preterm birth and/or intrauterine inflammation, and child’s sex assigned at birth - were identified as key contributors, collectively explaining a large variation in ADHD risk ranging from 8% to 66% through their additive and interactive effects.
Aim 2 assessed the association between maternal and cord plasma lipid metabolites and childhood ADHD risk in 701 mother-child pairs (378 ADHD, 323 neurotypical) using lipidome-wide association analysis with adjustment for multiple tests. While no significant associations were observed for maternal lipids, 104 cord plasma lipid metabolites across 15 classes were significantly associated with ADHD risk, with most showing positive associations with ADHD.
Aim 3 explored potential biological pathways linking maternal nativity (U.S.-born vs. non-U.S.-born) to offspring ADHD risk via mediation analysis in 690 mother-child dyads (317 ADHD, 373 neurotypical). Two cord plasma fatty acids - myristoleate and myristoleic acid - each mediated approximately 20% of the association between maternal nativity and ADHD risk.
Collectively, these findings highlight the additive and interactive influence of multiple early-life risk factors on ADHD development and suggest the cord plasma lipidome as a potential early biomarker of ADHD risk and a window into possible biological pathways. If validated in future studies, these results may inform innovative strategies for early risk assessment, targeted screening, and preventive interventions
Evolution of the feeding and sensory systems in secondarily aquatic carnivorans
No full textSecondarily aquatic transitions represent some of the most dramatic shifts among amniotes. Within Caniformia, two clades independently evolved aquatic ecologies: pinnipeds (seals, sea lions, and walruses) and lutrines (otters). Both exhibits derived anatomical and behavioral traits suited for aquatic life, yet retain strong ties to land for essential biological functions. Their close phylogenetic relationship, independent transitions, and varying reliance on aquatic versus terrestrial environments provide a unique opportunity to study the interplay of
ecological, developmental, and functional mechanisms during this transition.
This dissertation focuses on transformations in the feeding and sensory systems, key interfaces through which mammals perceive and interact with their environment. While addressing specific hypotheses about the origins and mechanisms behind these derived morphologies, the work also engages broader questions of adaptation, constraint, and developmental patterning in mammalian evolution. The research addresses three major gaps: the evolution of homodonty in pinnipeds, the presence and morphology of the vomeronasal organ in lutrines, and the relationship between vision, olfaction, and diving in pinnipeds.
The results show that the loss of precise occlusion between upper and lower dentition correlates with shifts in covariation between the upper fourth premolar and lower first molar patterns, evident even in early stem pinnipeds that are ecologically like otters. Additionally, the data suggest that the proposed developmental mechanisms do not fully account for these morphological changes. I also confirm the presence of the vomeronasal organ in lutrines, revealing that reduced vomeronasal gene repertoires in otters and true seals are not reflected in the organ’s anatomy. Lastly, I find no link between vision or olfaction and diving depth in pinnipeds, nor evidence that vision constrains olfaction due to spatial or energetic pressures.
Overall, these findings highlight discordance among genetic, behavioral, and morphological traits, emphasizing the need for integrated investigation of each component due to
the mosaic nature of these systems. While addressing the dissertation’s specific aims, this work identifies new research directions and challenges current assumptions about pinniped and otter biology, while refining our understanding of mammalian adaptation in aquatic environments
Oral History of L.K.
No full text“LK” discusses her parents, who immigrated to the United States from the Dominican Republic, growing up in Hollywood, Florida with three brothers while being homeschooled by her mother, and being a Girl Scout and playing violin from a young age. She discusses doing QuestBridge and deciding to attend Hopkins before it was a QuestBridge partner, her original plan to major in international studies and her choice to switch to majoring in history with a focus on East Asia, particularly Japan and Korea, minoring in music. She discusses her involvement in Latinas Promoviendo Communidad/Lambda Pi Chi Sorority and other groups on campus, and her experience with activism. She also talks about her experiences as a student with a disability, and the lack of support for FLI/first gen students who are humanities majors vs. STEM majors
ADULT LITERACY IN A DIGITAL WORLD: A MULTI-DIMENSIONAL CONCEPT FOR LIFELONG LEARNING
No full textThis dissertation was an exploratory study of the workplace literacy program in Singapore to inform adult teaching and learning of language literacy. Language literacy has remained a critical concept to ensure individuals can lead meaningful and economically active lives. However, it has been redefined as a multidimensional concept that includes reading and writing diverse textual materials and the use of technology as a literacy tool. Literacy educators play a direct role in teaching language literacy to adults and raising their literacy proficiency; however, they carry out their work in a complex and dynamic system, where their teaching in the program is shaped by policy and the provider who engaged them, and where language as a subject is used and applied in diverse work and living contexts. The culturally responsive teaching concept guided the analysis and understanding of the research findings. It was applied to both the teaching practices of the literacy trainers and the learning experiences and outcomes of the learners. The data collection covered both trainers’ views of their practices and how they engaged learners and carried out those practices regarding social and economic digitalization. Some of the teaching practices used were culturally responsive, but other practices had proven effective. The learners' observations and interviews also confirmed the effectiveness of these teaching practices. Unexpected findings related to program and assessment design and alignment were identified, suggesting areas for improvement and further research
UNDERSTANDING THE RELATIONSHIP BETWEEN SPACE UTILIZATION AND STUDENT SATISFACTION ON UNIVERSITY CAMPUSES
No full textThis dissertation explored the relationship between space utilization and student satisfaction at a university located in the Northeastern United States. The factors related to this research question were identified, nested, and organized within Bronfenbrenner's (1977) ecological systems theory. In addition, this paper discussed how the concept of space was viewed within the literature: university space within a social-cultural context, university space as a resource used to advance the goals of an institution, and university space as the predominant location for teaching and learning. This dissertation presented a conceptual framework to understand the relationships between students, campus managers, and space utilization. The conceptual framework was used to build an empirical study at Northeast University examining how space was utilized within a multifunctional building on campus, the "Student Center." Finally, this dissertation identified several implications and actionable recommendations for campus managers and university leadership to support enhancing space utilization in ways that could improve the student experience within higher education institutions
THE ILLUSION OF FULL-INCLUSION: EXPLORING BARRIERS TO FULL-INCLUSION CLASSROOMS FOR NEURODIVERGENT STUDENTS
Get PDFThis mixed-methods study investigated secondary teachers’ self-efficacy, knowledge, and development to create full-inclusion classrooms for neurodivergent students through an explanatory sequential design. Two surveys measuring teacher self-efficacy and knowledge of school-based inclusive practices were administered to instructional staff (n = 18) at a Large Open Enrollment Charter High School (LOECHS) in the Southern U.S. region. Select participants (n = 8) opted in to the following qualitative portion of the study that consisted of classroom observations and focus group interviews, both conducted by the researcher. The results indicated potential causations that affect teachers’ ability to create full-inclusion classrooms that positively impact neurodivergent students’ learning that stem from the school’s allocation of resources, implementation for co-teaching structures, and instructional collaboration rooted in classroom differentiation strategies. These findings suggest a need for both teacher and leader professional development that centers classroom differentiation and an instructional strategies exchange to meaningfully include and positively impact neurodivergent learners in the full-inclusion classroom setting
THE OPPORTUNITY GAP IN READING BETWEEN MULTILINGUAL LEARNERS AND THEIR NATIVE ENGLISH-SPEAKING COUNTERPARTS
Get PDFThe following empirical study examined the opportunity gap in reading between Multilingual Learners (MLLs) and their native-speaking counterparts. Through the use of the Networked Ecological Systems Theory (EST) model, factors associated with the problem were explored at all levels. From the comprehensive literature review, teachers’ preparedness, beliefs, and pedagogy were identified as three factors that influence MLL success in reading and require more context-based research. Following this research, semi-structured interviews were conducted among seven educators at SouthSide Elementary Charter School in Providence, Rhode Island. After an intensive coding process, seven themes emerged from the data. Based on the data, recommendations were provided to continue providing an excellent and empowering reading education for all students at SouthSide Elementary Charter School. This research is critical to ensure that solutions meet the needs determined by a crucial component of MLL learning- their teachers