VictorJuiz/thesis huggingface dataset:
High Contrast Gratings for Integrated Optoelectronics

Integrated optoelectronics has seen its rapid development in the past decade. From its original primary application in long-haul optical communications and access network, integrated optoelectronics has expanded itself to data center, consumer electronics, energy harness, environmental sensing, biological and medical imaging, industry manufacture control etc. This revolutionary progress benefits from the advancement in light generation, manipulation, detection and its interaction with other systems. Device innovation is the key in this advancement. Together they build up the component library for integrated optoelectronics, which facilities the system integration./nHigh contrast grating (HCG) is an emerging element in integrated optoelectronics. Compared to the other elements, HCG has very rich properties and design flexibility. Some of them are fascinating and extraordinary, such as broadband high reflectivity, and high quality factor resonance - all it needs is a single thin-layer of HCG. Furthermore, it can be a microelectromechanical structure. These rich properties are readily to be harnessed and turned into novel devices./nThis dissertation is devoted to investigate the physical origins of the extraordinary features of HCG, and explore its applications in novel devices for integrated optoelectronics. An intuitive picture will be presented to explain the HCG physics. The essence of HCG lies in its superb manipulation of light, which can be coupled to applications in light generation and detection. Various device innovations, such as low-loss hollow-core waveguide, fast optical phased array, tunable VCSEL and detector are demonstrated with the HCG as a key element. This breadth of functionality of HCG suggests that HCG has reached beyond a single element in integrated optoelectronics; it has enabled a new platform for integrated optoelectronics.

Advisor: Chang-Hasnain, Constance J
Reckless Occupations: Encroachment and Estrangement among Dogs and Humans in Delhi

This dissertation examines human and dog interactions in Delhi, India. In this project I follow the multiple ways in which dog and human life rub up one upon the other. This approach to thinking about how entities encroach upon each other emerged from living with a particular pack of dogs in relationship to other dogs in one neighborhood. Becoming caught in a particular pack of dogs and their human supporters or detractors organized my possible interactions and ability to meet, greet, acknowledge or to know about particular dogs and humans in this neighborhood. Becoming caught in specific scenes, where references to any general belonging of type such as categories of species, country, breed or specific family lineages or inheritances could not always be at the forefront of what was organizing sociality and alliances, helped make visible how encroachments and avoidances and solidified and fragile histories of sensing can be understood at the level of individual entities, be they human or dog./nThis specificity of movements of humans and dogs helped me think about understandings of encroachment, or how sneaking, creeping, hooking, seizing, impinging, and overreaching have influenced considerations of rightful occupations and invasions of both dogs and humans in Delhi. I examine this grasping, creeping and hooking in terms of juridical decisions about dog and human interactions, dog sanctuary experiments in living and relationships of kinship, servitude, the domestic and the interstice./nThe dog in Delhi is also a locus of some practices within which struggles over reformulations of categories such as caste and the foreign are taking place. Some uncomfortable correspondences and complicated histories of breed, class and kinship interpolate both dogs and humans in Delhi. A detailed examination of exceedingly provincial configurations of relationship and place that cannot be made into a generic sense of belonging of kind for either dogs or humans in Delhi can help us think about how understandings of servitude, rightful occupation, invasion, sanctuary and everyday estrangement might question some common-sense notions of family, belonging, inheritance, lineage and legacy, as well as what often gets glossed as the post-colonial in a locale such as Delhi.

Advisor: Cohen, Lawrence
Urban-bias and the Roots of Political Instability: The case for the strategic importance of the rural periphery in sub-Saharan Africa

Military interventions continue to be pervasive in Africa. Thirty out of forty-eight sub-Saharan states have experienced at least one successful coup. Nor have these numbers abated. In the 21st century alone, thirteen coups have been successfully staged in Africa, thus far. At the same time, several African countries - such as Ghana, Uganda, Burkina Faso and Benin - have managed to escape from seemingly insurmountable coup-traps. Yet, we understand little about what drives countries into a coup-trap and even less about how countries can extricate themselves from one. What explains this divergence? To address these contradictory trends, I focus initially on Ghana and Cote d'Ivoire, neighboring states, with comparable populations, topographies, and economies that have experienced contrasting trajectories. While Ghana suffered five consecutive coups from the 1966 to 1981, Cote d'Ivoire was an oasis of stability and prosperity. However, by the end of the 20th century, Ghana had emerged as one of the few stable two-party democracies on the continent, as Cote d'Ivoire slid into civil war. Why was Cote d'Ivoire so much more stable and prosperous than Ghana in the `60s and `70s? And what explains their dramatic reversal of fortunes?/nI answer these puzzles by examining the political strategies of regimes in both countries, with a particular focus on rural alliances. I find that the leaders who followed a rural political strategy were better able to preserve stability, while those who followed an urban political strategy were more likely to suffer coups. In contrast to the prevalent urban-bias thesis, I contend that traditional elites and producers in rural areas - not the organized urban sectors - are most critical to political stability. To show the wider applicability of my thesis, I extend my argument beyond these two countries. In a systematic review of fifty-eight regimes over eighteen sub-Saharan countries, I demonstrate that the rural/urban dichotomy is pervasive and predictive of the success/failure of regimes. Using formal modeling, I show a strong and robust correlation between supporting rural areas and the likelihood of being ousted in a coup as well as longevity in power

Advisor: Vogel, Steven K
Geospatial strategies to optimize placement of advanced bioenergy crops in marginal landscapes

As energy policies around the world progressively mandate increases in bioenergy production, the amount of land required to meet these demands might come at the cost of food production or environmental protection. To ensure sustainable practices, planting energy crops on marginal land is frequently proposed as a solution to this land use dilemma in order to meet mandates while avoiding negative externalities. Yet even though the term "marginal land" has become so entwined with discussions surrounding bioenergy, its definition is in fact malleable - easily shaped to fit research needs. This research investigates how marginal lands are commonly viewed in a Geographic Information Systems (GIS) framework and presents an innovative and flexible model that optimizes the placement of drought-tolerant bioenergy crops in marginal landscapes in the United States. In my first chapter, I present the first work that evaluates a suite of studies that use GIS to map marginal lands available for bioenergy production. In my second two chapters, I focus on the development of a site suitability model for several types of drought-tolerant bioenergy crops, which are of particular interest in the US because of their ability to grow on land not suitable for conventional agricultural production. In this work I demonstrate that incorporating fuzzy logic into the suitability model provides a more progressive suitability index that best synthesizes tradeoffs between multiple criteria. Using this model I present the first evidence to demonstrate that the area suitable for growing Agave as a bioenergy feedstock in the Southwestern US is sufficient to contribute to domestic renewable energy needs. I conclude that Agave would not be a major competitor to other energy feedstocks, but rather serve a parallel benefit as a renewable energy crop on lands unsuitable for conventional bioenergy production.

Advisor: Kelly, Maggi
Aircraft Design Optimization as a Geometric Program

Recent advances in convex optimization make it possible to solve certain classes of constrained optimization problems reliably and efficiently./nThese techniques offer significant advantages over general nonlinear optimization methods./nIn this thesis, conceptual-stage aircraft design problems are formulated as geometric programs (GPs), which are a specific type of convex optimization problem./nModern GP solvers are extremely fast, even on large problems, require no initial guesses or tuning of solver parameters, and guarantee globally optimal solutions./nThey also return optimal dual variables, which encode sensitivity information that is especially relevant in an aircraft design context./nThese benefits come at a price:/nall objective and constraint functions -- the mathematical models that describe aircraft design relations -- must be expressed within the restricted functional forms of GP./nPerhaps surprisingly, this restricted set of functional forms appears again and again in prevailing physics-based models for aircraft systems./nMoreover, for models that cannot be manipulated algebraically into the forms required by GP,/none can use methods developed in this thesis to fit compact GP models that accurately approximate the original models./nEach of these ideas is illustrated by way of concrete examples from aircraft design.

Advisor: Abbeel, Pieter
Scheduling and Optimizing Stream Programs on Multicore Machines by Exploiting High-Level Abstractions

Real-time streaming of HD movies and TV via YouTube, Netflix, Apple TV and Xbox Live is gaining popularity. Stream programs often consume considerable amounts of energy due to their compute-intensive nature. Making stream programs energy-efficient is important, especially for energy-constrained computing devices such as mobile phones and tablets. The first part of this thesis focuses on exploiting the popular Synchronous Dataflow (SDF) high-level abstraction of stream programs to design adaptive stream programs for energy reduction on multicore machines. Observing that IO rates of stream programs can vary at runtime, we seek to make stream programs adaptive by transforming their internal structures to adapt required occupied computing resources, e.g., cores and memory, to workload changes at runtime. Our experiments show that adapting stream programs to IO rate changes can lead to significant energy reduction. In addition, we also show that the modularity and static attributes of stream programs' abstraction not only help map stream programs on multicore machines more easily but also enable energy-efficient routing schemes of high-bandwidth stream traffic on the interconnection fabric, such as networks on-chip./nWhile SDF abstractions can help optimize stream programs on multicore machines, SDF is more suitable for describing stream data-intensive computations such as FFT, DCT, and FIR and so on. Modern stream operations such as MPEG2 or MP3 encoders/decoders are often more sophisticated and composed of multiple such computations. Enabling operation synchronization between different such computations with different semantics leads to the need for control messaging. We extend previous work on control messaging and give a formal definition for control message latency via the semantics of information wavefronts. This control-operation-integrated SDF (COSDF) is able to model sophisticated stream programs more precisely. However, the conventional scheduling method developed for SDF is not sufficient to schedule COSDF applications. To schedule COSDF applications, we develop a scheduling method using dependency graphs and applying a periodic graph theory, based on reduced dependency graphs (RDG). This RDG scheduling method also helps extract parallelism of stream programs. The more precise abstraction of COSDF is expected to help synthesize and generate sophisticated stream programs more efficiently./nAlthough the SDF modularity property also improves programmability, it can come at a price of efficiency when SDF models are not compiled and run using model-based design environments. However, compiling large SDF models to mitigate the inefficiency can be prohibitive in the situations where even a small change in a model may lead to large recompilation overhead. We tackle the problem by proposing a method for incrementally compiling large SDF models that faithfully captures the executions of original SDF models to avoid potential artificial deadlocks of a naive compilation method.

Advisor: Lee, Edward A
"Globalization" and the English Imperative: A Study of Language Ideologies and Literacy Practices at an Orphanage and Village School in Suburban New Delhi

This dissertation is a study of English language and literacy in the multilingual Indian context, unfolding along two analytic planes: the first examines institutional discourses about English learning across India and how they are motivated and informed by the dominant theme of "globalization," and the second investigates how local language ideologies and literacy practices correspond to these discourses. An ethnographic case study, it spans across four years. The setting is a microcosm of India's own complex multilingualism. The focal children speak Bengali or Bihari as a first language; Hindi as a second language; attend an English-medium village school; and participate daily in Sanskrit prayers. Within this context, I show how the institutional discursive framing of English as a prerequisite for socio-economic mobility, helps produce, reproduce, and exacerbate inequalities within the world's second largest educational system. The notion of globalization, further, is deeply woven into these discourses. I begin by showing that while top-level discourses about English accept globalization as doxa, little attention is paid to its differential intervention along socio-economic lines. My study complicates the commonly liberatory rhetoric of globalization by illuminating how such discourses employ multiple strategies to mobilize institutional voices in order to control and restrict access to linguistic, symbolic and economic capital. Further, fine-grained analyses of the children's linguistic practices and interview data reveal how local language ideologies counter, resist, and contest these discourses and voice enduring anxieties about English. Because these discourses have fueled the proliferation of private English-medium schools in India, catering mostly to the poor, the classroom forms another locus of investigation. Its analysis entails the close examination of literacy practices, curricula, and pedagogy at the children's school. The study reveals that factors such as multigrade classrooms; teacher-centered pedagogy; level-inappropriate textbooks; emphasis on rote memorization; and the difficulty of teaching and learning in a language in which neither the instructor nor the student has proficiency result in limited and superficial English acquisition and also limit children's access to educational content. In light of my findings, I argue that such English-medium schools not only widen the English-vernacular gap, they also reinforce the role of English in elite formation. The significance of my study lies in underscoring the ways in which institutional notions around English and globalization flatten out difference and enact erasure of local voices, with serious consequences for educational equity. This is not merely an Indian story; the role of English in an era of globalization is the high-stakes language politics story of our time.

Advisor: Sterponi, Laura
Phytochemical Regulation of Tumor Suppressive MicroRNA in Human Breast Cancer Cells

MicroRNA post-transcriptionally regulate more than half of the transcribed human genome and could be potential targets of anti-cancer therapeutics. The microRNA family, miR-34, is a component of the p53 tumor suppressor pathway and has been shown to mediate induction of cell cycle arrest, senescence, and apoptosis in cancer cells. Indole-3-carbinol (I3C) derived from cruciferous vegetables, artemisinin isolated from the sweet wormwood plant and artesunate derived from the carbonyl reduction of artemisinin effect components of the p53 pathway to growth arrest human cancer cells, implicating a potential role for miR-34 in their anti-proliferative effects. Flow cytometry and Taqman semi-quantitative PCR analysis of I3C, artemisinin and artesunate treated human breast cancer cells indicate all three phytochemicals upregulate miR-34a in a dose and time-dependant manner that correlates with a pronounced G1 cell cycle arrest. Western blot analysis revealed miR-34a upregulation correlates with induction of functional p53 by I3C as well as artesunate and artemisinin mediated decreases in estrogen-receptor alpha and the cyclin-dependant kinase CDK4, a known target of miR-34a inhibition. Luciferase assays in which cells were transfected with the miR-34a binding site of CDK4 mRNA attached to the firefly luciferase reporter gene confirmed miR-34a directly inhibits CDK4 expression in cells growth arrested by artemisinin or artesunate. Functional miR-34a appears critical for the anti-proliferative effects of I3C and artemisinin as transfection of non-translatable miR-34a inhibitors prevented I3C mediated growth inhibition and reversed artemisinin mediated down-regulation of CDK4. Artemisinin mediated down-regulation of ERα was also reversed in cells transfected with miR-34a inhibitors, implicating a novel role for miR-34a in the regulation of hormonal signaling. Transfection of dominant negative p53 prevented I3C upregulation of miR-34a in growth arrested cells containing wild-type p53 yet had no effect on artemisinin regulation of miR-34a, indicating a p53-indepedent mechanism of miR-34a regulation. Artemisinin and artesunate also upregulate miR-34a expression levels in breast cancer cell lines containing non-functional p53. All of these data suggest that miR-34a plays a critical role in the anti-proliferative effects of artemisinin, artesunate and indole-3-carbinol in human breast cancer cells. Such evidence elucidates the therapeutic potential of each phytochemical to ectopically express tumor suppressive microRNA while implicating the use of miR-34a expression levels to determine the efficacy of phytochemical treatment. Artemisinin, artesunate and I3C could represent an efficacious means of increasing tumor suppressive microRNA in vivo.

Advisor: Firestone, Gary L.
Dynamics of Coordination Complexes in Ground and Excited States

Metal coordination complexes represent the chief reusable tools of chemical transformation. Their flexibility and controllability are responsible for the success of numerous fields, from production of feedstock chemicals to medicine to solar energy conversion. Here, several aspects of the behavior of coordination complexes are explored, including the relationship between ligand design and spectroscopic properties. First, the mechanism of vibrational population transfer in trincarbonyl(η4-diene)iron "piano stool" complexes is explored via temperature-dependent 2D-IR spectroscopy and density functional theory (DFT). The "wagging" motion of the carbonyl ligands is characterized, differentiating it from chemical exchange. Second, the structure and energy of hydroxypyridinone-based (HOPO) MRI contrast agents were explored via DFT. This understanding of medicinal metals could allow for directed synthesis of promising future contrast agent candidates. Finally, the dynamics of electronically excited cobalt-zirconium heterobimetallic complexes were investigated with time-resolved IR spectroscopy and DFT. A short-lived singlet metal-to-metal charge transfer state was characterized that mitigated the original goal of the complex: catalytic CO2 reduction chemistry. Together, these experiments expand the knowledge of important coordination complex behavior in ground and excited states.

Advisor: Harris, Charles B
Hypersomnia in Bipolar Disorder: Clarifying a Diagnostic Dilemma

Context: Hypersomnia is poorly defined, though evidence suggests it is associated with a range of negative health outcomes, poorer quality of life, and increased new-onset and recurrence of psychiatric illness. Lack of definition impedes generalizability across research studies./nObjective: To clarify hypersomnia diagnoses by exploring the possibility of subgroups, along with their relationship to prospective sleep data and relapse into psychiatric illness, in a sample of individuals with bipolar disorder./nDesign: Prospective longitudinal analysis of a community psychiatric sample/nParticipants: The final sample included 159 adults (ages 18-70) with bipolar spectrum disorder diagnoses (I, II and NOS) who were euthymic at study entry./nMain Outcome Measures: Self-reports and clinician-administered interviews were used to determine features of hypersomnia, including habitual sleep duration, extent of excessive sleepiness, and napping. Participants completed sleep diaries and wore wrist actigraphy at home to obtain prospective sleep data in the home environment. Follow-up interviews were completed approximately seven months later and psychiatric status was assessed using the Structured Clinical Interview for the DSM-IV (SCID)./nResults: Factor analyses confirmed two separate subtypes of hypersomnia - a group characterized by long sleep time and a group characterized by excessive daytime sleepiness - that were uncorrelated (r=-0.09). Latent profile analyses suggested a four-class solution best characterized the data, with long sleep and excessive sleepiness representing two separate classes. Prospective sleep data suggested that the sleep of `long sleepers' is characterized by long time in bed, not long sleep duration. Finally, longitudinal assessment of psychiatric illness suggested that excessive sleepiness at baseline predicted mania/hypomania relapse at follow-up./nConclusions: This study is the largest investigation of hypersomnia to include objective measurement of sleep, and refines our understanding of classification, characterization and associated morbidity. Hypersomnia appears to be comprised of two separate subgroups, long sleep and excessive sleepiness. Long sleep is characterized primarily by long bedrest duration. Excessive sleepiness is not associated with longer sleep or bedrest, but predicts relapse to mania/hypomania. Understanding these entities has important research and treatment implications.

Advisor: Harvey, Allison G