VictorJuiz/thesis huggingface dataset:
Understanding the contribution of microbial processes to the concentration and isotopic composition of nitrite in the surface ocean
Keywords: Sustainability.
Environmental Earth System Science.

Nitrite is a key intermediate in many biological reactions in the marine nitrogen cycle, yet nitrite does not typically accumulate to measurable amounts in the ocean. While oceanographers have observed a consistent nitrite accumulation at the base of the euphotic zone for decades, we still do not fully understand what controls the formation and maintenance of this feature. In this dissertation I investigate the major microbial processes that produce and consume nitrite in the oxygenated surface ocean of the eastern tropical North Pacific (ETNP) in order to understand the relative response of key microbial groups to fluctuating environmental conditions and their net effects on nitrite accumulation in the primary nitrite maxima (PNM). The highest net nitrite production rates were observed near the depth of the PNM, where ammonia oxidation is a dominant process. However, high net nitrite production did not correlate with high concentrations of accumulated nitrite. The integrated signal of microbial activity recorded in the natural abundance isotopes of nitrite over weeks to months was used to calculate relative rates of production and consumption processes, resulting in rate estimates of similar magnitude to directly measured rates. Understanding the balance in microbial processes contributing the PNM refines our estimates of nitrate-fueled primary production and will help identify conditions that may cause increased nitrous oxide production in the surface ocean
Understanding the interactions of 2D materials and guest species for quantum and energy applications
Keywords: Engineering.
Electrical Engineering.

The deliberate introduction of guest species into a material to modify its physical properties has been a subject of extensive research for a long time, with a well-known example being doping in semiconductors. The emergence of two-dimensional (2D) materials with a layered structure opens new opportunities for guest species in two distinct interactions: gating and intercalation. These methods allow for reversible modulation of 2D materials without disrupting covalent bonds. This dissertation presents the development and application of guest-species modulation in 2D materials for potential quantum and energy applications. Three specific examples are discussed, including the creation of a 3D magnetic superlattice and 2D magnetic monolayer through interlayer engineering of magnetic van der Waals Fe3GeTe2; the observation of an intermediate state during lithium intercalation in twisted bilayer MoS2; and the development of a catalysis transistor to dynamically control the hydrogen evolution reaction. This dissertation demonstrates the control of 2D materials for desired functions through an understanding of the gating and intercalation interactions of guest species and 2D materials, paving the way for new advancements in quantum and energy technology
Understanding the link of arterial structure and functional outcomes during growth and regeneration
Keywords: Humanities and Sciences.
Biology.

The coronary arterial vasculature undergoes distinct developmental phases to reach its adult structure. Coronary arteries (CAs) have an inner cellular layer composed of endothelial cells. These cells are specified early in development before blood flows through the primitive coronary vasculature. Subsequently, the arterial network matures and experiences significant expansion during its initial weeks of life, defining its final architecture. The chapters in this study reflect the approaches used to understand the connection between arterial structure and functional outcomes during growth and regeneration. In these projects, our objectives are to determine the cellular origins of the CA tree, examine how CAs structure influences function, and investigate the response of CA architecture to injury. By utilizing advanced whole-organ and clearing imaging techniques, we examined the entire artery network and discovered that specific endothelial cells in the coronary capillary bed are predisposed to transform into arterial cells during postnatal growth. Furthermore, we observed that neonatal coronary arteries exhibit distinct responses to injury and collateral artery development, which may explain their superior regenerative capabilities compared to adult arteries. Lastly, we investigated the genetic variant associated with coronary artery dominance in humans to explore its causality. This research illuminates the structure and development of coronary arteries, with implications for cardiovascular medicine.
Understanding tumor suppression through the p53 target gene network
Keywords: Medicine.

TP53 encodes the potent tumor suppressor, p53. TP53 is mutated in nearly half of sporadic human cancers, and inheritance of a mutant TP53 allele in the germline causes Li-Fraumeni Syndrome, which highly predisposes those affected to developing cancer early and often in their lives. Cementing the importance of p53 in tumor suppression are the data from p53 null mice, which succumb within months to mostly thymic lymphomas with 100% penetrance. Despite its unequivocal importance in tumor suppression, the precise mechanisms of p53-mediated tumor suppression remain incompletely understood. p53 is a stress-inducible transcription factor. In response to various cellular stresses, p53 accumulates in the cell, binds to DNA in a sequence-specific manner, and activates expression of target genes. Various pieces of evidence support this transcriptional activation p53 as being critical for tumor suppression. Notably, genetically engineered mouse models of cancer demonstrate that inactivation of both p53 transactivation domains (TAD) renders p53TAD1,2 comparable to p53 null alleles in tumor suppression. The p53 target gene network encompasses hundreds of genes that regulate diverse cellular processes. Our understanding of which p53 target genes and which biological processes are key to p53-mediated tumor suppression remains incomplete. Factors that complicate answering these questions are that study of p53 target genes has largely focused on in vitro studies using acute p53-activating stresses and that p53 might suppress tumorigenesis in a context-specific manner. To address this question of which p53 target genes are most important for tumor suppression, we have developed a sensitive, in vivo, combinatorial screening platform. Using a comprehensive sgRNA library targeting 272 target genes of p53, we identified Zmat3 and Cdkn1a as potent and cooperative effectors of p53-mediated tumor suppression. Using meta-analyses of published p53-dependent gene expression studies in human cell lines as well as CRISPR/Cas9 screening data compiled in the Cancer Dependency Map, we demonstrated that ZMAT3 and CDKN1A are near-universal, evolutionarily conserved target genes of p53 that serve as brakes to enhanced cellular fitness in pooled sgRNA enrichment screens. Finally, using RNA-seq, differential splicing analysis, and shotgun proteomics, we link Zmat3 and Cdkn1a loss with dysregulation of signal transduction and cell division respectively, suggesting that, through these two target genes, p53 engages parallel cellular processes in tumor suppression. These studies illuminate important modules of p53-mediated tumor suppression, an understanding that could contribute to the improved diagnosis and treatment of p53-deficient tumors in the clinic
Unequal Provision of Educational Accommodations: Impacts of a Nationwide SAT Policy Change on Receipt of Accommodations
Keywords: Educational sociology, disability, accommodations
Text
Thesis

Educational accommodations are provided to support students with disabilities in the classroom. Previous research shows that students of privileged backgrounds obtain accommodations at higher rates than minority and low-income students, although research is inconclusive with respect to why these disparities exist. In this paper, I present causal evidence on the impact of an exogenous change in the incentive to obtain an accommodation. In 2016, the College Board introduced a policy stating that the accommodations provided in a student's 504 plan would automatically carry over to the SAT. By streamlining the receipt of accommodations for the SAT via 504 plans, this policy created a new incentive to seek a 504 plan, as 504 plans could now confer desirable advantages on a high-stakes college admissions test. To estimate the effect of this policy change, I employ a difference-in-differences approach using administrative data from over 9,000 public schools in the United States. I find that the policy change significantly increased 504 plan receipt among white students at wealthy high schools, but not among comparable subgroups like minority students at wealthy schools or white students at high-poverty schools. These findings shed light on some of the motivations that may lie behind accommodations-seeking, and demonstrate how current practices of accommodations provision may inadvertently perpetuate educational inequality.
Uniaxial heterostrain in twisted bilayer graphene above the magic angle
Keywords: Humanities and Sciences.
Physics.

Twisted bilayer graphene is an experimentally rich platform, hosting a variety of exotic states of matter with an unprecedented degree of tunability. I present measurements of a twisted bilayer graphene device twisted to 1.4 degrees, well above the magic angle at which correlations dominate. Despite the lack of correlated states, the device shows several unexpected behaviors in magnetotransport: regions in density of large quadratic magnetoresistance concurrent with an apparently non-Diophantine Landau fan diagram. I show that uniaxial heterostrain of only a few tenths of a percent neatly explains these unusual magnetotransport measurements. It is presently difficult to control such small amounts of strain in experiments. If we can control it, then heterostrain becomes a powerful tuning knob to control the band structure of twisted bilayer graphene, much like twist angle.
Uniform Transition Tree-Structured Critically Sampled Filterbanks
Keywords: Electrical Engineering
Electrical engineering
Signal processing
Filterbanks
Audio coding
Text
Thesis

Critically sampled filterbanks are useful in applications like audio coding that involve processing the time-varying spectral characteristics of signals. Critically sampled filterbanks can be implemented with a tree-structure. The odd-numbered subbands of a critically sampled filterbank exhibit frequency inversion, causing subbands to be unordered in frequency past the first layer. We show how subbands can be swapped at each layer to maintain their ordering. Self-similar filterbanks, using the same filters at each layer of the tree, have nonuniform transition widths and long impulse responses. We explore using filters with wider transition widths at deeper layers, and we demonstrate that this technique can be used to implement an efficient uniform transition filterbank. We compare this uniform transition filterbank with a self-similar filterbank in an audio codec, showing that the uniform transition filterbank achieves a smaller maximum transition width at a lower impulse response length.
Unity and Struggle Beyond Borders: An Examination of Anti-Hindutva Activism in the United States
Keywords: Religion
Caste
Transnationalism
South Asian Americans
Activism
Text
Thesis

This thesis is an endeavor to study the organized resistance against Hindutva in the United States, exploring the development of contradictions between Hindutva and anti-Hindutva movements, as well as explaining current contentions within the anti-Hindutva movement. I start by tracing the historical development of global Hindutva, from its origins in India towards its current manifestations in the United States. Then, through a combination of analysis of semi-structured interviews from representatives from three anti-Hindutva organizations (Ambedkar King Study Circle, Hindus for Human Rights, and Indian American Muslim Council), as well as the examination of digital documents and reports, I explore the current landscape of anti-Hindutva activism in the United States. In particular, I consider how the issues of Hindu majoritarianism and caste discrimination have mobilized South Asian American and Indian American communities to oppose Hindutva both in India as well as within the United States. I specifically argue that the current anti-Hindutva movement has increasingly resisted against the expression of Hindutva politics within the United States through analyzing two key incidents - the protests against the appearance of a bulldozer at an Indian Independence Day rally in August 2022 at Edison, NJ, and the February 2023 passing of an ordinance against caste discrimination in Seattle. I also explore contentions within the anti-Hindutva movement in the United States, explaining how the relationship between caste and Hindutva has led some anti-Hindutva organizations to emphasize the distinction Hindutva from Hinduism, while others have offered a deeper critique of caste violence that opposed Hindutva, but also investigates the Brahmanical origins of caste and its relationship to Hinduism. Despite certain disagreements about the relationship of caste, Hindutva, and Hinduism, I maintain that critical unities between organizations have featured prominently in the successful actions against Hindutva in the United States. I also note how these solidarities have extended beyond just the issues of Hindutva, arguing that the fight against Hindutva in the United States has become increasingly connected to other struggles for liberation, from anti-capitalist struggles to the battle against racism.
Universal optical instrumentation for exoplanet atmospheres
Keywords: Humanities and Sciences.
Physics.

Any astronomical inferences rely fundamentally on a model of the universe which incorporates relevant physical processes of the system in question. These models enable experimentation in otherwise inaccessible environments by providing a fictitious copy of the universe in which researchers can control the initial conditions or governing equations to disentangle cause and effect. An increasing number of experiments rely on astrophysical objects as essential components in the instrumentation, with various physical mechanisms forming the operating principle through which inferences are ultimately drawn. This has blurred the preexisting conventions which distinguish the human constructed instrumentation from the environment in which they operate as well as the objects under investigation. A complete understanding of astrophysical instrumentation will require a hierarchical modeling strategy which incorporates all relevant physical processes over all scales to connect observations to inferences. Analysis of optical propagation through the turbulent atmosphere of the Earth demonstrates a fundamental limitation to single-deformable-mirror adaptive optics systems such as the Gemini Planet Imager as a result of scintillation. At the other end of the optical path, turbulent mixing in exoplanetary atmospheres can result in chemical abundances of molecules such as carbon monoxide which depart from equilibrium expectations, changing the near-infrared colors of the planet. Lastly, explorations of novel instrumentation such as a starshade and the solar gravitational lens may enable unprecedented observations of other worlds
Universal properties of the intrinsic microbial response to temperature fluctuations
Keywords: Humanities and Sciences.

The impact of temperature on growth is typically considered only under heat- or cold-shock conditions that elicit specific regulation. Over intermediate temperatures, the growth rate of all cells varies according to the Arrhenius law of thermodynamics; growth rate dynamics during transitions between temperatures remain mostly unstudied. Using a device that enables single-cell tracking during switches across a wide range of temperatures (0 °C to 47 °C), we show that many bacteria respond to temperatures upshifts on a characteristic time scale of ~1.6 doublings at the higher temperature, regardless of initial/final temperature or nutrient source. We rule out transcriptional, translational, and membrane reconfiguration as potential mechanisms, and instead discover that an autocatalytic enzyme network incorporating temperature-sensitive Michaelis-Menten kinetics recapitulates all temperature-shift dynamics and successfully predicts the altered temperature responses observed under simple-sugar and low-nutrient growth conditions. These findings suggest that the temperature sensitivity of metabolite flux dictates responses to temperature fluctuations.
Univirtual Academy
Keywords: VR
IVR
CSCL
Collaboration
Virtual Learning Environments
Socialy Sharhed Regulation
Scaffolding
Checklists
Pro-social Prompting
Intelligent Social Agents
ISA
Cognitive Load
Text
Capstone
Report
Thesis
Student project report

The use of Immersive Virtual Reality (IVR) platforms is increasingly being considered as a vehicle for remote work and in K-12 distance learning. Because collaboration skills are vital for students' holistic growth and the future job market, the need for new approaches to collaboration support in immersive digital learning environments is growing. Computer-supported collaboration scripting and comprehensive training are identified as potential ways to address group work support and improve learning outcomes in IVR-based learning environments. The project focus is on the purposeful design of the online environment fostering self-efficacy and scaffolding to achieve effective collaboration and produce socially shared regulation. The findings of this project have significant implications for teaching and learning collaboration skills in synchronous IVR-based learning environments, where students' trajectories can be divergent and unanticipated. The project seeks to prepare students for the collaborative technological future of remote teamwork by leveraging VR affordances and automated real-time pro-social prompting.
Addendum 1.0
Virtual Reality (VR) learning environments provide immersive and interactive experiences that have the potential to enhance educational outcomes. Collaborative problem-solving tasks in VR environments require effective communication and cooperation among group members. Intelligent Social Agents (ISAs) are computer-based characters programmed with human-like attributes that can interact and collaborate with users in the virtual world. This report aims to investigate the impact of ISA personality on reducing cognitive load when groups collaborate on problem-solving tasks in VR learning environments. The report combines information gathered from literature to analyze ISA personalities' potential effects and implications on cognitive load, group interactions, and learning experiences in this context.
Unlocking opportunity, advancing equity : improving college outcomes for marginalized students
Keywords: Education.

Empirical evidence unambiguously asserts that a college education provides robust benefits to both individuals and societies. However, disparities in college enrollment and completion persist and limit opportunities for marginalized students to enjoy the advantages a college education affords, impeding progress toward equitable outcomes for all. The three chapters in this dissertation employ quantitative methods to evaluate policies and programs that aim to improve college access and success for marginalized students. The first chapter evaluates efforts to increase college access for rural students and revitalize rural economies. Results suggest a strong positive effect of branch campus openings on local economic activity. The second chapter estimates the differential impact of changes to the federal student loan policy on Historically Black Colleges and Universities (HBCUs) relative to other institutions. Results suggest that HBCUs are more responsive to these policy changes and experienced a disproportionately negative effect on enrollment when access to loans was restricted. The third chapter estimates the impact of a virtual college coaching intervention designed to help low-income, first-generation, and racial/ethnic minority students persist to degree completion. Results suggest that coaching has a positive effect on persistence to the second year, but that effect is not sustained beyond the intervention period. Together, these chapters provide evidence that informs efforts to unlock opportunity for all students and advance equity in college access and completion
Unpacking gender segregation within occupations : a study of job queues and social closure mechanisms in the medical profession
Keywords: Humanities and Sciences.
Sociology.

When women make inroads into men-dominated professions and occupations, how should we interpret these trends? While there has been an overall stall in the gender integration of occupations in the 21st century, the one exception is women's entrance into men-dominated managerial and professional roles. Substantial literature has focused on this significant demographic trend. However, considerably less literature has delved into understanding the gender-segregating process within occupations and between specialties and how these processes interact and intersect at both the occupational and specialty levels. The importance of filling this gap is underscored by the fact that within-occupational processes explain a significant proportion of wage inequality in the United States. This dissertation aims to fill this theoretical and empirical gap in the literature through a case study of the medical profession, which has been feminizing over the past four decades, with equal numbers of men and women now graduating from medical school. I argue that the same processes influencing gender segregation between occupations also affect gender segregation within occupations. Furthermore, I contend that supply side factors, specifically how workers rank specialties within an occupation (referred to as "the job queue"), play a crucial role in the gender-segregating process within an occupation and can be leveraged to increase women's representation in men-dominated specialties. My dissertation comprises three separate empirical studies. In the first study, I apply principles from community ecology literature to investigate how relative decreases in rewards, compared to the occupation as a whole, in a specialty significantly influence job queues within occupations, independent of absolute decreases in rewards in that specialty. In my second study, I identify and examine the defining features of social closure mechanisms that create opportunities for women to enter specialties within an occupation. Building on these findings, in my third study, I construct a typology of social closure mechanisms within an occupation. I empirically analyze how supply and demand side mechanisms mediate the relationship between the types of social closure mechanisms in an occupation and subsequent specialty choices. Together, these studies highlight that women and men rank specialty characteristics similarly, providing opportunities for social closure mechanisms within a specialty to be structured in ways that decrease gender segregation within occupations.