VictorJuiz/thesis huggingface dataset:
Stratification through Organizational Identity: Charter School Ideologies and Segregation in the Era of Accountability

Research shows charter schools are more segregated by race and class than traditional public schools. I investigate an under-examined mechanism for this segregation: Charter schools project identities corresponding to parents’ race- and class-specific parenting styles and educational values. Such identities are constituted by conformity and uniqueness claims reflecting cultural logics—especially the ascendant logic of school accountability, which compels standardization despite pressures on charter schools for locally situated innovation./nTo analyze these tensions, I use computational text analysis to detect emphasis on educational ideologies in the websites of all charter schools operating in 2015-16. In particular, I use Structural Topic Models to discover a range of latent themes; I then use word embeddings and dictionary methods to measure inquiry-based learning (IBL), a particularly niche-specific ideology. Finally, I implement mixed linear regression models to test the relationships between ideological emphasis and school- and district-level poverty and ethnicity. I thereby transcend methodological problems in scholarship on charter school identities by collecting contemporary, population-wide data, and by blending text analysis with hypothesis testing./nI find that the websites of schools serving white and affluent students and districts are more likely to emphasize academics (e.g., course information, IBL), while schools serving those in poverty or people of color place greater emphasis on standards, college preparation, and programs and services for the disadvantaged (e.g., nutrition, virtual learning). For IBL, precise statistical models show that these relationships are robust, even when objective measures of school quality are considered. These findings suggest charter school identities are both race- and class-specific, outlining a new mechanism by which school choice may consolidate parents by race and class—and paving the way for behavioral and longitudinal studies. This dissertation contributes to literatures on school choice, quantitative methods, and educational stratification.

Advisor: Haveman, Heather A.
Integrated Hybrid Switched-Capacitor Converters for Point of Load Power Delivery

The Hybrid Switched-Capacitor (SC) converters have shown potentials for higher efficiency andpower-density compared with magnetic and pure SC converters. These advantages have driven new architectures and control schemes suitable for power converters integration in advanced CMOS technology nodes by alleviating the device stress and size. This work focuses on integration of the popular hybrid Dickson SC and cascaded resonant SC converters for high efficiency and power- density DC-DC conversion in datacenter and embedded applications covering few mW to hundreds of W load range. The first test chip is a hybrid Dickson SC converter for battery powered embedded and mobile applications where the demand focuses on high efficiency and power-density across a large conversion ratio of 3.4 V - 4.2 V for Lithium-ion batteries down to 0.3 V - 0.9 V with load range up to 1.5 A for digital processors and peripherals in advanced CMOS technology nodes. The second test chip is dual-phase time-interleaved extension of the hybrid Dickson SC converter designed with coupled-inductor and multiple outputs for application in multi-core processors with dynamic volt- age scaling. The focus of the second test chip is improved efficiency through time-based control and dual-phase operation as well as a higher power-density through compact die-stacked packaging of passive components. The converter is designed for input voltage range of 3.2 V - 3.6 V DC bus conversion down to load voltage of 0.7 V - 1 V with load range up to 1.4 A. The third test chip integrates gate-driver, bootstrap and control peripherals of the cascaded discrete resonant SC converter for higher power conversion from 48 V DC bus down to 6 V intermediate bus. The focus of the third test chip is design of a single-package peripheral for improved efficiency and power- density. In addition, integrating the start-up and shutdown peripherals enables hot swapping in datacenter applications.

Advisor: Pilawa, Robert
Genetic basis and evolutionary context for structural color shift in the Buckeye butterfly

In butterfly scales, nanostructures that scatter light create structural color, often with/nvisually delightful effects like iridescence. Structural colors used for signaling, thermal/nregulation, or camouflage provide excellent case studies in the ecological/nmultifunctionality of color. Developmentally, intricate nanostructures must be precisely/nsculpted, as a few nanometers’ difference in one dimension would change the hue. In/nphysics, the gyroid, an infinitely connected periodic surface once thought to be a purely/ntheoretical shape, was found reflecting green light in butterfly wings, and naturally/noccurring photonic structures are a rich source of inspiration for optical engineering./nDespite interdisciplinary appeal, the biological processes that produce structural color/nremain mysterious. Here, I take a telescopic approach to investigate the biology of/nbutterfly structural color, beginning with macroevolutionary trends, proceeding to/ngenus- and species-level variation, and concluding with genetic analysis. In chapter one,/nI aggregate reflectance and morphological data for all 350 described butterfly structural/ncolors to interrogate the color gamut and phylogenetic distribution of structural color./nIn the process, I comprehensively review what is known about how structurally colored/nscales develop and evolve. In chapter two, I show that selective breeding shifted wing/ncolor from brown to blue in buckeye butterflies (Junonia coenia) via a 74% increase in the/nthickness of each scale lamina. By comparing ten related species in the genus Junonia, I/nfind that evolutionarily tuning lamina thickness has generated a wide range of/nstructural colors, from gold to magenta and green. A similar thickness increase explains/nthe appearance of blue scales in buckeyes with mutations in the optix wing patterning/ngene. In chapter three, I use a large cross-breeding experiment between blue and brown/nbuckeyes and quantitative trait locus mapping to identify genetic loci that control the/nevolved blue structural color. Hue is controlled by a different set of genes than the/narrangement of blue scales over the wing surface, and optix is the first specific gene/nfound to regulate the morphology of a photonic structure.

Advisor: Patel, Nipam H
Nachman, Michael W
Securing the Sahel: Nature, Catastrophe, and the Empire of Expertise

This dissertation considers the proliferation of security interventions in the West African Sahel led by the European Union, United States, and various United Nations agencies. I argue that the region has become a privileged site in the making of novel forms of security expertise, which assemble an ever-expanding range of events as actionable threats. I investigate how a diverse series of challenges—political violence, terrorism, trafficking, migration, anthropogenic climate change—are drawn together under a governing rubric of security. Amid invocations in the popular press and scholarly literature about numerous looming global catastrophes, my project considers how security emerges as a form of expert knowledge marshaled to govern catastrophe. Through a mix of ethnographic and archival methods situated in three regional nodes— Dakar, Senegal; Ouagadougou, Burkina Faso; and Niamey, Niger—my project empirically locates contemporary security expertise within the particular geo-histories of the Sahel. While several accounts of contemporary security interventions in the region are quick to write these developments exclusively into a post-9/11 counterterrorism lineage that begins in the early 2000s in the Middle East and East Africa and effectively expands outward into West Africa in subsequent years, my dissertation seeks to empirically trace a different genealogy of security practice. I treat security interventions in the Sahel as polyvalent practices, presently concerned with terrorism and organized crime, while simultaneously informed by a range of deeper anxieties about arid and semi-arid spaces. My research demonstrates how intertwined geopolitical and environmental imaginaries are refashioning the Sahel as a geographic site in need of continuous foreign-led monitoring, surveillance, and security.

Advisor: Watts, Michael
The Impact of R&D Classification Shifting in High-Technology Industries

This study examines the use of classification shifting from cost of sales to research and development (R&D) to myopically overstate gross profits and R&D in high technology industries. Moving beyond the conventional earnings management paradigm, I explore the incentives and motivations driving the usage of R&D classification shifting as an expense management tool. I find that R&D classification shifting increases the likelihood of meeting or beating gross margin benchmarks and is used to show steady growth in firm performance. I use case studies to supplement my empirical results and provide further insights into the motivation and practice of R&D classification shifting. Prior literature concentrates on the determinants but not the consequences of R&D classification shifting. My study investigates the impact of R&D classification shifting on future R&D productivity, stock returns, and operating performance. I find evidence that firms engaging in R&D classification shifting exhibit lower future R&D productivity because the shifted portion of R&D does not yield innovative outputs. The negative effects of R&D misclassification are further evidenced by lower future stock returns and operating performance. Taken together, my results indicate that the short-term benefits of meeting or beating gross margin benchmarks are offset by the long-term negative impact of R&D overstatement.

Advisor: Patatoukas, Panos N.
Konchitchki, Yaniv
Mechanistic Studies of Pd-Catalyzed C-N Bond Forming Reactions

This dissertation discusses the development of aminocarbonylation reactions with ammonia and either an aryl or alkyl halide, coupling reactions between hydrazine and aryl halides, and studies of the mechanisms of these two classes of reactions. The synthesis and reactivity of arylnickel(II) amido complexes is also described./nChapter 1 presents an overview of Pd and Ni-catalyzed C-N coupling reactions. This chapter includes a description of the development of these reactions and a synopsis of the mechanistic studies that have been conducted for each C-N coupling reaction. This chapter also describes the challenges faced when developing systems to catalyze C-N coupling reactions with hydrazine and the mechanistic questions related to that transformation, which have gone unexplored. Pd-catalyzed carbonylative cross-coupling reactions are also discussed, and the mechanism of key elementary steps in these reactions are outlined, which were recently elucidated by work in our group./nChapter 2 presents a study of the mechanism of a Pd-catalyzed aminocarbonylation reaction between chloroarenes and ammonia. The mechanism of this reaction was proposed based on kinetic, spectroscopic, and computational data. Additionally, 13C KIE measurements and a Hammett analysis were performed to obtain further data on the mechanism of oxidative addition of a chloroarene to a three-coordinate Pd(0) carbonyl complex. A catalyst deactivation pathway, which involved the formation a Pd(I) dimer with bridging carbonyl and hydride ligands, was also elucidated, and the rate-limiting step of the catalytic reaction was shown to be the oxidative addition of chloroarene to Pd(0)./nChapter 3 details efforts to develop and study a Pd-catalyzed aminocarbonylation reaction between aniline and alkyl bromides. Preliminary data obtained for this aminocarbonylation reaction are consistent with oxidative addition of the alkyl halide to a Pd(0) species by a mechanism involving an alkyl radical./nChapter 4 describes the synthesis and reactivity of a small library of arylnickel(II) amido complexes, which have been crystallographically characterized and are stable at room temperature./nChapter 5 presents the development and mechanistic study of a Pd-catalyzed C-N coupling reaction between aryl chlorides and hydrazine. Aryl hydrazines can be synthesized in high yield and with catalyst loadings as low as 300 ppm by this protocol. Several examples of aryl hydrazines are provided that are relevant to the synthesis of agrochemicals. The synthesis of an arylpalladium(II) hydrazido species was undertaken and demonstrated to undergo reductive elimination to give aryl hydrazine. Additional mechanistic studies were performed that identified two resting states of the catalyst, an arylpalladium(II) chloride species and an arylpalladium(II) hydroxo complex. The hydroxo compound reacts with hydrazine to give aryl hydrazine, but this palladium complex was demonstrated to be unselective towards mono- versus diarylation of hydrazine.

Advisor: Hartwig, John F
Popular Judicial Legitimacy: A Computational Text Analysis of Social Media Coverage of Apex Courts in Taiwan and the United States

By studying the social media apex court news in Taiwan and the United States, this dissertation aims at providing new evidence to the institutional legitimacy literature, specifically, whether the existing legitimation such as legal language is still relevant, and to what extent do competing themes of political wrangling challenge the procedural fairness models of judicial legitimacy in the current social media culture./nThe dissertation consists of two main parts. First, drawing upon topic modeling techniques, it will review the topics on social media news outlets to see how the traditional legitimacy factors —the powerful symbols of justice and procedural fairness come into play. Both Twitter and Facebook data confirm the procedural fairness models are still relevant. Nevertheless, the justice confirmation procedures in the United States involve considerably more political wrangling themes./nSecond, this dissertation studies the judicial legitimacy affect in social media news coverage. It tests whether the judicial language styles in networked news coverage are associated with positive affect more often than with negative affect, and finds quite opposite results in Taiwan and the United States./nThe dissertation thus intends to make the following contributions. Methodologically, it ties a variety of tools, including topic modeling and sentiment analysis, to the measurement of legal language, positivity bias and judicial legitimacy affects. In so doing, it debunks the processes of contemporary judicial legitimation, and lays out the vital communication process of judicial information.

Advisor: Mayali, Laurent
Activity-Based Sensing and Proteomics to Study Formaldehyde in Biological Systems

Formaldehyde is a potent electrophile engaging in reactions at nucleophilic amino acid residues, DNA and RNA bases, and biological metabolites. While traditionally viewed as an environmentally-sourced toxin, recent evidence has emerged indicating formaldehyde is produced endogenously at high micromolar concentrations through cellular processes such as one-carbon metabolism, N-demethylation reactions, and spontaneous folate degradation. Biochemical studies show the intracellular production and metabolism of formaldehyde is directed to preserve the carbon unit on formaldehyde for productive one-carbon metabolism and biosynthetic processes, rather than unspecific release leading to toxic side reactions. This dissertation describes the development of activity-based sensing methods to selectively image formaldehyde in living organisms and proteomics methods to determine proteome-wide reactivity of formaldehyde on nucleophilic amino acid residues. Historical perspective on the development of activity-based sensing methods is provided as context for the development of methods for formaldehyde detection. Development of a general reaction-based trigger utilizing the aza-Cope reaction allowed the functionalization of a palette of fluorescent reporter molecules for formaldehyde detection, and we applied a red-emitting fluorescent probe to verify an endogenous metabolism process for formaldehyde via glutathione and alcohol dehydrogenase 5. We then applied the formaldehyde trigger to develop organelle targetable probes for interrogating formaldehyde fluxes across intracellular compartments. The formaldehyde trigger also enabled functionalization of chemiluminescent dioxetane scaffolds, allowing us to visualize endogenous formaldehyde release from folate degradation in a living mouse model. Finally, activity-based proteomics methods reveal formaldehyde hyper-reactive cysteine residues are specific to enzymes involved in one-carbon metabolism processes, and not ubiquitous across the proteome. We show an isoform specific inhibition of formaldehyde on S-adenosylmethionine synthetases, revealing a feedback loop of formaldehyde to regulate the methylation potential of the cell.

Advisor: Chang, Christopher J
Estimating global policy impacts in unprecedented contexts with interdisciplinary econometric approaches

Global policy challenges, such as addressing climate change and improving global health, require coordinated international efforts. Enacting such policies is often hampered by difficulties in quantifying the public benefit brought about by action. Without this information, policy decisions may focus primarily on the costs of action and thus disproportionately harm the groups for which inaction enacts the most damage. While classical econometric approaches are designed to identify policy impacts, they fall short when globally representative data is missing or when present or future contexts have no clear historical precedent. In these situations, new approaches are needed to incorporate evolving global data sources, such as satellite imagery, and process-based understanding from relevant fields, such as climate science or epidemiology. This dissertation leverages recent computational advances to develop and apply scalable tools for incorporating these data and models into policy impact estimation. Specifically, the first chapter describes a novel method for quickly extracting socio-environmental measurements using satellite imagery and machine learning. The second and third chapters describe applications of interdisciplinary methods to (a) project climate-driven changes to hurricane damages and (b) estimate the effect of COVID-19 policies on the pandemic's spread. In general, the findings suggest that the previously unmeasured benefits of global action in these contexts are substantial, and they demonstrate how such interdisciplinary approaches can better inform policy-making for complex global challenges.

Advisor: Hsiang, Solomon M
Cytoplasmic mRNA decay represses RNA polymerase II transcription during early apoptosis

The life of an mRNA molecule is often depicted as a unidirectional flow of discrete stages – transcription by RNA polymerase II (RNAPII), nuclear export, translation, and degradation – with distinct means of regulation occurring at each step. However, a growing body of work has revealed complex crosstalk between stages of this process that is integral to the proper regulation of cellular gene expression. Although such crosstalk often involves compensatory changes to buffer mRNA transcript levels, enhanced transcriptome-wide mRNA decay instigated by viral endonucleases instead causes a global repression of mRNA synthesis. This feedback is not dependent on the specific viral endonuclease but rather hinges on the catalytic activity of host mRNA decay factors. In this regard, a central question is whether this mRNA degradation-transcription feedback loop is unique to viral infection or if it represents a universal response to cellular stress. Early apoptosis has recently been identified as a context in mRNA transcripts are globally degraded. To test whether apoptosis-driven mRNA decay causes transcriptional repression, steady-state and nascently transcribed RNA were measured concurrently in the presence or absence of a death-inducing ligand. Global RNAPII transcription is reduced during early apoptosis in a manner dependent on mitochondrial outer membrane permeabilization-induced mRNA decay by cytoplasmic 3’-end decay factors. Chromatin immunoprecipitation (ChIP) experiments revealed that this apoptotic transcriptional defect elicited by 3’-end mRNA decay is associated with impaired RNAPII recruitment to promoters. Cytoplasmic RNA binding proteins (RBPs), such as PABPC, increase in nuclear localization during apoptotic mRNA decay. Blocking nuclear import severs the link between cytoplasmic mRNA decay and transcription in both the viral endonuclease and apoptosis contexts, suggesting that it is the transport of RBPs from the cytoplasm to the nucleus that links these two processes. These observations point to a mode of gene regulation in which enhanced mRNA leads to a further shutdown in mRNA transcription, representing a conserved cellular response to intrinsic or extrinsic threats.

Advisor: Glaunsinger, Britt A
Total Reconstitution of Receptor-mediated Ras Activation by SOS In Vitro

Ras GTPase activation is part of an important class of signaling reactions that take place on membrane surfaces in cells. This membrane-anchored protein functions as binary switch that relays information to many essential intracellular signaling pathways. Some of the most aggressive cancers are caused by mutations in Ras, making it a clinical target of paramount importance. Cells have evolved multiple layers of regulation that tightly control Ras signaling, including enzymes that control the activation state of Ras, membrane specificity, allosteric mechanisms, and two-dimensional protein phase transitions. At the center of this regulation is the guanine nucleotide exchange factor (GEF), Son of Sevenless (SOS). SOS is a key Ras activator that is autoinhibited in the cytosol and activates upon membrane recruitment in response extracellular stimuli. In addition to its GEF activity, SOS facilitates a phosphotyrosine-driven phase transition by crosslinking proteins at the membrane./nThis dissertation aims to delve into the molecular processes and mechanisms behind the multilayered regulation of Ras activation by SOS. First, we extended an in vitro reconstitution platform of Ras on supported lipid bilayers (SLB) to include a real-time imaging readout of Ras activation. We engineered the Ras binding domain (RBD) of Raf1 kinase, which exhibits a natural selectivity for the active Ras-GTP state, to have rapid and fully reversible binding to Ras-GTP. This platform was then applied to the investigation of the allosteric activation of SOS and positive feedback. We found that allosteric Ras binding is a necessary, but not exclusive feature of a processive activation state observed in SOS. However, the nucleotide specificity in allosteric Ras binding promoted SOS processive activity, suggesting an alternate pathway to establish positive feedback in Ras activation. Finally, the Ras SLB platform was extended to include membrane inputs necessary to reconstitute the receptor-mediated recruitment of SOS and formation of two-dimensional protein assemblies. This work identified that the receptor-mediated membrane recruitment and release of autoinhibition introduces a kinetic threshold to the duration of SOS membrane dwells for effective signal propagation. The phosphotyrosine-driven phase transition modulates signaling by increasing the probability of SOS enzymes crossing this kinetic threshold. Collectively, these findings are suggestive of a kinetic proofreading mechanism in Ras signaling, where spurious signals from short dwells are filtered, and true signals from long dwells are propagated and amplified by the processive activity of SOS.

Advisor: Groves, Jay T
Healy, Kevin E