VictorJuiz/thesis huggingface dataset:
Opinions about Hispanics [electronic resource] : causes and consequences
Keywords: Political Science.

Racial divisions have shaped American society since colonization. In the last half- century, social science researchers have proposed a variety of theories about the origins of negative opinions of different racial group. From this body of work, we have learned a great deal about race-based opinions, and these findings have been used in attempts to alleviate racial discrimination. A great deal of the study of race relations and racial opinions in the U.S. has focused on the black-white divide. However, a host of societal changes has made evident that the black-white dichotomy is no longer the only politically relevant racial division in the United States. Hispanics have been the largest minority group in the United States since 2000 and are the fastest growing ethnic group, increasing approximately 3.1% per year. Hispanics accounted for more than half of the population growth between 2008 and 2009, and the United States now has the second largest Hispanic population in the world. In addition, demographic patterns indicate that the relative growth of the Hispanic population will not cease. Over one fourth of all children in the U.S. under the age of 5 are of Hispanic descent, and 61% of Hispanic households include children under the age of 18. The Hispanic population is younger than the non-Hispanic population (median ages of 27.4 and 36.8, respectively). Of the 21 million eligible Hispanic voters, however, only 9.7 million cast ballots in 2008, resulting from a combination of high numbers of non-citizens, the youth of the population, Hispanics being concentrated in lower income and education categories, and non-immunization of immigrants. This makes Hispanics a "sleeping giant" in American politics. The changing ethnic and racial composition of American society makes obvious an exciting opportunity for the academic literature on racial opinions - the exploration of negative attitudes toward Hispanics. Broadly speaking, I do so by examining sources and consequences of opinions about Hispanics among non-Hispanic whites. By building on the theories used to examine anti-black racism, I explore how opinions about Hispanics originate and how these attitudes relate to opinions on public policies, particularly Arizona's SB 1070.
Optical pumping of single donor-bound electrons in zinc selenide and silicon [electronic resource]
Keywords: Physics

The spin of single electrons bound to donors in semiconductor materials are promising candidates for quantum bits implementations. These electrons have been shown to be very homogenous and have extremely long decoherence times in a bulk semiconductor environment. In this work, I have studied two donor systems as quantum bit candidates, with a focus on using optical pumping methods to initialize and measure the electron and nuclear spins of the donor system. The first donor system, fluorine in zinc selenide, is a very optically bright system which is a particularly good candidate for quantum repeater technologies. The relatively large electron binding energy leads to a stable qubit at low temperatures, and the potential for isotopic depletion of nuclear spin from the host semiconductor crystal suggests very long decoherence times can be achieved. In this work, I confirm the isolation of a single F-bound electron, and present results on the use of resonant optical pumping to initialize the electron to a particular spin state. These results open the door for optical control of the electron spin as a qubit. The second donor system, phosphorus in silicon, is the semiconductor system with the longest published decoherence times, obtained for the nuclear spin of the donor. Due to the long excited-state lifetime of the donor optical transitions, the linewidth of the transition is narrower than the hyperfine splitting, allowing optical access to the donor nuclear spin. However, to date, single phosphorus donors have not been optically isolated. In this work, I present a theoretical description of a hybrid optical and electrical device for the measurement of a single phosphorus donor nuclear spin. If experiments can confirm the properties of this device, this measurement technique would provide a key element for a silicon-based quantum computer.
Optimal control for despin of underactuated tumbling satellites [electronic resource]
Keywords: Aeronautics and Astronautics

A critical issue that must be addressed to enable on-orbit servicing of satellites or removal of space debris is how to capture and despin an object that may be tumbling. The scenario addressed by this work is the case of a damaged or uncooperative tumbling object. Such an object could be a non-responsive "zombiesat'' that needs to be serviced, or a piece of space debris that needs to be removed. This scenario is of particular importance because uncooperative tumbling objects can pose a danger to active satellites in nearby orbits. Servicing tumbling satellites requires several steps. One of the most critical is to despin the satellite, i.e. to drive its angular momentum towards zero. Solving for the optimal thruster commands to perform the despin is computationally complex, especially when the actuation is severely limited as can be the case for an uncooperative tumbling satellite. This problem can be solved in principle using existing numerical dynamic programming (NDP) methods, but the data storage requirements of the solution exceed the capabilities of current satellite computers. Closed form solutions also exist, but only for special cases with specific thruster orientations, inertia properties, and cost functionals. This dissertation describes a control approach that provides a reduced computational cost solution to the despin problem for severely underactuated satellites undergoing general tumbling motion. The approach is based on an NDP algorithm, but the data storage requirements are reduced by up to three orders of magnitude and the computation time requirements are reduced by up to one order of magnitude through a selection of novel ``trajectory'' state and staging variables that incorporates the underlying dynamics into NDP. Only the rotational degrees of freedom are considered in this work. Simulation and experimental results are presented. Simulations were performed for two important tumbling satellite scenarios and demonstrate the computational benefits of using trajectory state and staging variables in NDP. Laboratory experiments were performed using a small-scale tumbling satellite simulator and demonstrate the viability of the control approach.
Optimal design of health insurance plans [electronic resource]
Keywords: Management Science and Engineering

High deductible health insurance plans have been advocated as a measure to control rising healthcare expenditure, by reducing the moral hazard associated with 3rd party insurance and encouraging cost-effective behavior. Despite the increasing use of demand-side cost-sharing, the optimal design of health insurance schemes is not very well understood nor easy to apply. As such, economic theory has not had a major influence on design of health insurance schemes. This dissertation examines aspects of designing and implementing high deductible insurance schemes. First, I examine the optimal coinsurance rates of primary prevention, diagnostic services and office visits. In many observed health plans, these services are often exempt from deductibles. The Affordable Care Act also mandates that private health plans must cover a stipulated list of preventive services at zero coinsurance with no deductible. I show that optimal coinsurance rates for primary prevention are always higher than the coinsurance rates for associated treatment for risk-neutral individuals; and if the uninsured portion of treatment expenditure is sufficiently large or probability of illness is sufficiently small for risk-averse individuals. This probability is given by the threshold under which a risk-averse individual will undertake more prevention. We also identify similar thresholds for diagnostic services and they show that optimal coinsurance rates are always higher than associated treatment coinsurance in most circumstances. These results suggest that additional justifications have to be sought in setting prevention and diagnostic coinsurance below that of treatment. This dissertation also develops an easily applicable formula for optimal nonlinear coinsurance rates using a perturbation method. This method has the advantage of being extended to solve optimal deductible levels with fixed coinsurance rates as compared to Blomqvist(1997)'s derivation using optimal control theory. The application of this formula to observed health insurance plans, distribution of expenditures and risk aversion provides maximum bounds (in absolute terms) for elasticity estimates. Similarly from elasticity estimates, we can also obtain lower bounds of risk aversion. I apply these formulas to generate optimal coinsurance rates and deductible levels for observed expenditure distributions and elasticities in the RAND HIE. Finally, I study Medical Savings Accounts (MSAs) which are usually coupled to high deductible health insurance schemes. The effectiveness of MSAs depends on the extent to which consumers value Medisave dollars less compared to cash dollars because of restrictions imposed on the use of MSAs. Using individual-level data of hospital ward choice in Singapore, we estimate that consumers value Medisave dollars at 80 cents to a dollar in cash.
Optimization and adjoint-based CFD for the conceptual design of low sonic boom aircraft [electronic resource]
Keywords: Aeronautics and Astronautics

For future civil supersonic aircraft to have the operational flexibility offered by current subsonic aircraft, some means of reducing their sonic boom to acceptable levels is required. An effective technique by which the sonic boom ground signal may be altered, and potentially minimized, is through careful shaping of external features of the aircraft. By considering the detailed aircraft shape using nonlinear flow solvers, accurate assessments of sonic boom can be made during multi-disciplinary conceptual design optimization. Such capability would enable the development of aircraft satisfying not only a requirement on low boom, but also on the range of constraints and mission goals necessary to produce a viable aircraft design. This work presents a multi-level framework for the conceptual design of low sonic boom aircraft. The development of a robust, automated tool using output-driven mesh adaptation enables accurate prediction of sonic boom. Results are validated with available experimental data for a variety of signal forms. An approach combining linear supersonic potential theory with atmospheric propagation and loudness prediction methods is used to generate low-boom near-field signals subject to lift and equivalent area constraints. This signal generator is then used to build a response surface fit that enables a conceptual-level design optimization to develop aircraft configurations with low boom. The imposition of a diverse range of multi-disciplinary design constraints ensures a viable aircraft. Once a satisfactory baseline is obtained, the design is transferred to the CFD domain, where an adjoint-driven inverse design approach is used to determine the detailed aircraft shape. This optimization seeks to match the near-field pressure target associated with the conceptual baseline design, subject to geometric constraints that ensure conceptual-level performance predictions are preserved. An aircraft design example is presented, demonstrating the application of this approach on a supersonic business jet.
Optimization of a plasmonic-enhanced photodetector design [electronic resource]
Keywords: Electrical Engineering

This thesis covers the design and investigation of a plasmonic-grating enhanced photodetector structure that consists of a series of concentric gratings around a bull's eye that is split to form a metal-semiconductor-metal photodetector. Finite-difference-time-domain (FDTD) studies were carried out in order to study and simulate the different parameters of the photodetector design. A fabrication process was suggested that makes use of two lithographic mask layers in order to fabricate the basic metal-semiconductor-metal photodetector structure in InGaN where the bull's eye grating is to be patterned on. Initial fabrication work was done on making the concentric gratings and bull's eye structures using focused-ion-beam milling on a metal layer as a test. In addition, these plasmonic-grating enhanced photodetector structures were shown to be wavelength selective, and such a characteristic can be used to design multi-spectrum detectors for bio-sensing. A design for a multi-spectrum biosensor using microfluidic channels and multiple plasmonic-grating enhanced photodetectors is also described in the thesis.
Optogenetic tool development and application to dissecting dopaminergic circuitry in social behavior [electronic resource]
Keywords: Neurosciences.

Social interaction is an essential and highly integrative behavioral task that is impaired in major psychiatric disorders such as autism, schizophrenia, social anxiety disorder, and depression. Current treatments for many of these disorders are based on pharmacological approaches that have been used for decades even though their mechanisms of action are poorly understood and carry many side effects. In particular, treatment of the asocial symptoms of these disorders has remained elusive due to a generally poor understanding of the neural circuitry underlying normal social behavior. In order to move toward a deeper circuit-level understanding of these complex neural processes, our lab has pioneered the use of two light-activated microbial opsins, Channelrhodopsin-2 (ChR2) and Halorhodopsin (NpHR), to achieve precise bidirectional optogenetic control of specific cell types in behaving animals. However, it has become clear that the complexity of the circuitry involved in psychiatric behaviors will require new classes of optogenetic tools to modulate cells in a more refined manner based on characteristics such as projection profile, receptor expression, and endogenous firing patterns. The purpose of this study was thus two-fold: 1) to develop novel optogenetic tools for more physiologically relevant stimulation of different cell types on different timescales, and 2) to apply these tools to define in socializing animals the real-time causal role not only of a specific brain region and cell type, but also of distinct subpopulations defined by projections to different downstream brain regions and distinct downstream cell types. The engineered opsins we develop here will be generalizable to dissect other neural circuits in health and disease, enabling new domains of optogenetic investigation that have thus far been inaccessible, and enhancing the precision of optical neural control in a broad variety of settings.
Order out of chaos [electronic resource] : Fernando Pessoa and Eugeni d'Ors and the crisis of modernism
Keywords: Iberian and Latin American Cultures.

This is the first study comparing the works of the contemporary intellectuals Fernando Pessoa and Eugeni d'Ors. It examines their use of heteronyms, heterodoxy, and history in approaching the crises that arose in the beginning of the twentieth-century. Each applied an aesthetic understanding to reality. A full understanding of reality required the multiplication of the self in an attempt to achieve an objective--decentralized--perspective. For Pessoa, this meant the creation of a host of heteronyms that led in a progression to a centralizing figure. For d'Ors an internal divine attribute of the human psyche approached objectivity through dialogue. In fact, dialogue is found as a connective theme in Pessoa as well. This aesthetic perspective becomes a gateway into a deeper understanding of reality. This understanding in turn shapes the present and future through the aesthetic works of each of these authors. In this way, Pessoa and d'Ors conceived of a present in which the future could be shaped through an aesthetic understanding of the world. The striking similarities of their approaches speak to the hidden interconnectedness of Iberian cultures.
Organic electronics [electronic resource] : devices, circuits and applications
Keywords: Electrical Engineering

Organic materials have brought exciting opportunities for flexible, light weight, low cost, and disposable electronics. However, there are still several technical challenges for the wide spread of this technology. In this dissertation, I discuss about the challenges and the improvements of organic electronics. In the first part, I explore device engineering for organic thin film transistors (OTFTs). New device architecture and fabrication methods to improve the OTFT characteristics are proposed. Short channel and self-aligned OTFTs are implemented on a non-planer substrate. The self-aligned structure enables accurate alignment between the electrodes with a pre-defined prism-structure dimension, thus reducing parasitic overlap capacitance. In the second part, circuit engineering based on OTFTs is studied. An OTFT circuit design methodology is proposed to enable accurate analysis and verification in the design stage. Various topologies of digital circuits such as complimentary and unipolar OTFT circuits based on this design methodology are demonstrated. The third part focuses on application engineering, specifically on the implementation of disposable and flexible organic electronic sensors. Wireless temperature sensor based on conductive filled polymer is demonstrated. The stability and reproducibility is improved and the sensitive temperature can be tuned by employing a binary polymer system.
Organic geochemical reconstructions of the late quaternary climate history of the Sierra Nevada [electronic resource]
Keywords: Geological and Environmental Sciences.

Organic geochemical proxy measurements in sediments from Swamp Lake, Yosemite NP, in the central Sierra Nevada of California provide evidence of climatic change on millennial and centennial timescales over the last ~20,000 years. Proxy measurements in bulk sediments (TOC, TN, C/N, [delta]13Corg, [delta]15N, biogenic silica, magnetic susceptibility) record the response of the lake environment, in terms of primary productivity, OM sources, microbial OM regeneration and secondary production, and detrital input, to climate-driven changes in temperature, seasonal ice cover, lake mixing regimes, runoff and lake level. Parallel changes in the relative abundances of n-alkane biomarkers provide more specific information about lake level during the Holocene epoch. The inferred environmental changes at Swamp lake correlate with other Sierra Nevada paleo-records, and with reconstructed sea surface temperatures along the California margin. Parallel changes in the Swamp Lake and SST records over the past ~20,000 years provide new evidence that continental climate in the Sierra Nevada and the California Current system have responded, on multiple timescales, to common drivers in North Pacific ocean-atmospheric circulation. Measurements of compound-specific hydrogen isotope ratios in sedimentary leaf wax n-alkanes ([delta]Dwax) provide insight into the nature of the link between North Pacific and Sierra Nevada climate over time. The [delta]Dwax composition of Swamp Lake sediments is primarily controlled by changes in the [delta]D of precipitation, which is in turn influenced by the moisture sources and trajectories of winter storms. The Swamp Lake [delta]Dwax record reveals a long-term change in precipitation seasonality and/or storm trajectory over the Holocene, driven by seasonal insolation, as well as centennial- to millennial-scale fluctuations reflecting changes in the relative importance of northerly and southerly storm types. These apparent "regime shifts" in North Pacific atmospheric circulation resemble modern, short timescale responses to ENSO and the PDO, but their underlying causes remain unknown.
Overcoming the last mile of humanitarian and health delivery supply chains [electronic resource] : models and insights
Keywords: Management Science and Engineering

The "last mile" of a supply chain is the final step of that supply chain before the product reaches the end consumer. In humanitarian and health delivery supply chains, the last mile represents the final leg of the journey for health care or other assistance to reach beneficiaries, and is a critical bottleneck contributing to the acutely inadequate health care access in resource-limited regions. Operations research methodology can be used to evaluate, lessen, and ultimately overcome this bottleneck. In this dissertation, we present four models developed for this context. First, we develop an inventory model to analyze the interaction between a stockpile and a downstream relief operation for large humanitarian organizations such as the United Nations High Commissioner for Refugees. Second, we present an optimization model that explicitly includes treatment adherence when integrating a clinic's capacity decisions with population health outcomes. Our final two models investigate the effectiveness, then the efficiency and equity, of fleet management programs for health worker vehicles (e.g., nonprofit Riders for Health) in places like rural sub-Saharan Africa. Health access challenges are fundamentally supply chain problems, and these models are a first step in using operations research tools to improve health delivery in resource-limited regions. Humanitarian organizations must use their financial resources wisely to carry out their mandates, and models such as these can help organizations make the best use of their limited response resources.
Oxytocin enhances signal-to-noise in hippocampal feed-forward transmission by selective action on targeted interneuron subtypes [electronic resource]
Keywords: Molecular and Cellular Physiology.

Neural circuits throughout the brain are under the continuous influence of neuromodulators which shape network activity in accordance with behavioral context. Oxytocin is a key neuromodulator that has been linked to social memory and maternal behavior in animals, as well as to autism spectrum disorders, trust, emotion recognition and parenting in humans. Here we show that activation of oxytocin receptors sharpens the responses of the hippocampal circuit, increasing the signal of spike transmission through the network while simultaneously suppressing the noise of background spontaneous activity. Both of these actions are mediated through a depolarization of the fast-spiking interneurons. The resulting increase in inhibitory tone serves to silence spontaneous activity in the CA1 pyramidal cells, while a use-dependent depression of the inhibitory synapses permits enhanced feed-forward spike transmission. Furthermore, we show that oxytocin potently modulates spontaneous hippocampal Sharp-Wave Ripple oscillations in a slice preparation. These results elucidate the action of oxytocin in the hippocampus, while simultaneously shedding light on a novel mechanism by which modulation of fast-spiking interneurons can modify hippocampal circuit activity.