VictorJuiz/thesis huggingface dataset:
Awakening the Sleeping Giant: Campaign Strategies, Political Parties, and the Puzzle of Asian American Under-participation in Electoral Politics

Asian Americans' peculiar combination of high levels of socioeconomic attainment, high rates of citizenship acquisition, and low rates of voting defies conventional sociological theories of assimilation, which tend to view political integration as occurring in step with socioeconomic integration; and traditional political science theories of political engagement, which emphasize socioeconomic determinants of participation. It also complicates the position advanced by some social scientists that Asian Americans are "becoming white." Beyond the theoretical puzzle, low rates of electoral participation from one of the fastest-growing segments of the American population have sobering implications for the practice of democratic self-governance and the representativeness of public policies./nIn this dissertation, I approach the puzzle of Asian American under-participation in electoral politics from a contextual perspective by investigating how different political contexts change the extent to which Asian Americans under-participate in the electoral process. I employ a multi-method research design, beginning with statistical analyses that identify the correlates of under-registration and under-voting among Asian American citizens. I find that it is at the registration stage where Asian American "exceptionalism" in the sense of an unusually large and unexplained degree of under-participation in electoral participation occurs. I then perform an in-depth comparison of two California counties that differ substantially in their magnitude of Asian American under-registration relative to whites, and in their values of the correlates./nI find that the incentives for electoral candidates and political parties to target Asian Americans for registration differ substantially between the two counties, and that the mobilization strategies that follow from those uneven incentives are what accounts for the difference between the counties in the degree of Asian American under-registration. I conclude that, when political agents are incentivized to target Asian Americans for mobilization, the gap in voter registration between socioeconomically comparable Asian and white American citizens is significantly reduced. The missing piece in the puzzle of Asian American under-participation in electoral politics is political mobilization.

Advisor: Bloemraad, Irene
Omi, Michael
Experimental Studies of the Tribological Behavior of Microelectromechanical Systems

Microelectromechanical systems (MEMS) are used in a wide range of applications including sensors, actuators, biomedical devices, projection systems, and photovoltaic structures. Advances in MEMS have increased the demand for more reliable microstructures. The reliability and performance of many MEMS devices depends strongly on the tribological properties of contact interface. Knowledge of the origins and evolution of the surface forces is therefore important to the design of MEMS devices with contact interfaces. In this dissertation, special microdevices fabricated by surface micromachining were used to characterize interfacial phenomena encountered under typical operation conditions of MEMS devices. Dynamic impact and sliding contact experiments were performed to determine the critical parameters of device lifetime. The evolution of static adhesion force and friction force was examined under controlled loading and environmental conditions. A criterion of micromachine failure due to excessive interfacial adhesion (stiction) was formulated based on the observed experimental trend. Surface modification was examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), and the observations were compared to the evolution of critical interfacial properties. The change of the interfacial force was explained in the context of nanoscale surface modification effects resulting in both physical and chemical surface changes. The deposition of self-assembled monolayer (SAM) films is one of the most promising surface chemical treatments for preventing micromachine stiction during release and operation. The tribological properties of micromachine sidewall surfaces coated with a conformal FOTS film were also investigated in the context of goniometry measurements, adhesion and static friction tests, and X-ray photoelectron spectroscopy (XPS) results. This study extends the understanding of the effect of interfacial phenomena on the operation of contact-mode MEMS devices, and the obtained results are valuable to the improvement of MEMS reliability.

Advisor: Komvopoulos, Kyriakos
Rejuvenation of the Aged Stem Cell Niche: Signal Transduction and Reversing the Decline of Adult Hippocampal Neurogenesis and Myogenesis

Although functional organ stem cells persist in the elderly, tissue damage invariably overwhelms tissue repair, ultimately leading to the failure of major organ systems. It has been demonstrated that the microenvironment, or niche in which adult stem cells reside critically influences stem cell function. The delicate balance between positive and negative signaling regulators controls the decision of adult stem cells to remain quiescent, self-renew or differentiate, a crucial balance for the maintenance of tissue homeostasis. In this dissertation, we provide evidence that the same key morphogenic signaling pathways become deregulated with age and contribute to the decline of both hippocampal neurogenesis and skeletal muscle regeneration with aging, leading to the decline in regenerative performance of both brain and muscle tissue stem cells. Furthermore, we demonstrate that the aged tissue niches can be rejuvenated to enhance native stem cell function in muscle and brain by youthful calibration of the intensity of these morphogenic signaling pathways. In particular, local attenuation of BMP signaling in the aged hippocampus, systemic and local attenuation of TGF-beta signaling in both the aged hippocampus and aged skeletal muscle, and specific proteins secreted by human embryonic stem cells that act through MAPK and Notch signaling rejuvenate brain and muscle tissue precursor cell function by normalizing the signaling strength of the pathways that are chronically overexpressed or underexpressed with aging. Summarily, by better understanding the age-imposed decline in the regenerative capacity of stem cells, the debilitating lack of organ maintenance in the old, including decline in neurogenesis and skeletal muscle regeneration, can be ameliorated.

Advisor: Schaffer, David
Conboy, Irina
Effects of semi-natural environmental conditions on phenotypic plasticity in Rattus norvegicus

Controlled laboratory experiments find there is normal variation in maternal care that regulates the development of the endocrine, cognitive and behavioral responses to stress in rats. As housing conditions of laboratory rats can have pronounced effects on experimental outcomes, I examined how semi-naturalistic environmental conditions affect maternal care and how or if variation in maternal care affects neural and behavioral development in adult female offspring. Specifically, I assessed maternal behaviors in semi-natural enclosures and what effects, if any, alternative maternal strategies might have on the development of stress physiology and cognition in adult offspring. I found semi-natural housing conditions decreased variation in maternal care, litter size, and offspring survival regardless of the amount of maternal care provided to pups, but increased pregnancy success in dams phenotyped as lower maternal care providers in laboratory housing, suggesting there could be direct fitness benefits to providing lower levels of maternal care. I also found significant environmental effects on adult offspring stress reactivity and behavior as well as cognition and hippocampal cell proliferation that are not mediated by maternal care, unlike previous laboratory findings. Collectively these analyses underscore the critical role of environmental context on maternal behavior and its behavioral and physiological outcomes

Advisor: Francis, Darlene
Kaufer, Daniela
Towards Evidence-Based Assessment of Factors Contributing to the Introduction and Detection of Software Vulnerabilities

There is an entire ecosystem of tools, techniques, and processes designed to improve software security by preventing, finding, mitigating, and/or eliminating software vulnerabilities. Software vendors have this entire ecosystem to choose from during each phase of the software development lifecycle, which begins when someone identifies a software need, ends when the software vendor decides to halt support for the software, and includes everything in between./nUnfortunately, guidance regarding which of these tools to choose is often non-existent or based solely on anecdotal evidence. In this dissertation, we present three studies to demonstrate that empirical studies can be used to enhance our understanding of the effectiveness of various tools and techniques intended to improve software security./nIn our first study, we use a data set of 9 implementations of the same software specification in order to explore the relationship between web application development tools and the security of the applications developed using those tools. We found evidence that framework support for avoiding security vulnerabilities influences application security, that we can expect manual framework support to continue to be problematic, and that manual code review and black-box penetration testing are complementary techniques./nIn our second study, we hire 30 code reviewers to perform manual security reviews of a content management system in an effort to better understand the effectiveness of manual security review as a technique for vulnerability discovery. We found that level of experience and education do not correlate with reviewer effectiveness at code review, that overall reviewer effectiveness is low, and that there is significant variation amongst reviewers./nFinally, in our third study, we analyze a data set of rewards paid out over the course of two exemplar vulnerability rewards programs (VRPs), that of Google Chrome and Mozilla Firefox, in an effort to better understand the costs and benefits of such programs. We found that these VRPs appear economically efficient, comparing favorably to the cost of hiring full-time security researchers, that both programs have successfully encouraged broad community participation, and that Chrome's VRP has uncovered more vulnerabilities than that of Firefox despite costing almost exactly the same amount.

Advisor: Wagner, David
Aluminum Nitride Sensors for Harsh Environments

Harsh environment applications include high temperature, pressure and mechanical shock. Aluminum nitride is a strong ceramic material with very good high temperature survivability. It also has piezoelectric properties that can be used for sensing applications and it can be deposited with good control as thin polycrystalline film for the fabrication of micro-electromechanical systems. In this dissertation, optimized deposition parameters for aluminum nitride films and characterization techniques for film stress gradients are investigated. Furthermore, two different fabrication processes are presented that can be used to build several sensors and other micromechanical elements on a single chip. The more advanced process includes a bulk-micromachining step that enables the use of the silicon substrate as large proof masses for accelerometers. At the same time, the fabrication process can be used to create membranes for devices such as pressure sensors. Several different devices are discussed from the device design and theoretical analysis to the fabrication and experimental verification. The most significant contribution is the performance improvement of several orders of magnitude that can be achieved with aluminum nitride accelerometers by switching from double-ended tuning forks to triple-beam tuning forks and by using the newly discovered sensing concept of bent-beam sensing. Additionally, rate gyroscopes were presented that use aluminum nitride as the structural material and for both actuating the drive axis and reading the sense axis. Both types of sensors have potential applications in inertial navigation at high temperature. Double-ended tuning forks and triple-beam tuning forks were tested in hot environment and it was shown that they can be used as highly sensitive strain sensors up to at least 570~degC. Additionally, a testing setup for high temperature testing of accelerometers was demonstrated.

Advisor: Pisano, Albert P
Algebraic Geometry of Hidden Markov and Related Models

This thesis embodies a collection of algebraic techniques and results on hidden Markov models, related models in quantum physics called Matrix Product State models, and finally discrete directed acyclic graphical models./nChapter 1 explores the statistical problems of model selection and parameter identifiability from the perspective of algebraic geometry, in the case of hidden Markov models (HMMs) where all the hidden random variables are binary. Its main contributions are (1) a new parametrization for every such HMM via a birational map with an explicit inverse for recovering the hidden parameters in terms of observables, (2) a semialgebraic model membership test to determine if a discrete probability distribution can arise from such an HMM, and (3) minimal defining equations for the set of probability distributions arising from the 4-node fully binary model, com- prising 21 quadrics and 29 cubics, which were computed using Grobner bases in the cumulant coordinates of Bernd Sturmfels and Piotr Zwiernik. The new model parameters in (1) are rationally identifiable in the sense of Seth Sullivant, Luis David Garcia-Puente, and Sarah Spielvogel, and each model's Zariski closure is therefore a rational projective variety of dimension 5. Grobner basis computations for the model and its graph are found to be considerably faster using these parameters. In the case of two hidden states, (2) supersedes a previous algorithm of Alexander Schonhuth which is only generically defined, and the defining equations (3) yield new invariants for HMMs of all lengths ≥ 4. Such invariants have been used successfully in model selection problems in phylogenetics, and one can hope for similar applications in the case of HMMs./nIn Chapter 2, we study the representational power of matrix product states (MPS) with binary virtual bonds for entangled qubit systems. We do this by giving polynomial expressions in a pure quantum state's amplitudes which hold if and only if the state is a translation invariant matrix product state or a limit of such states. For systems with few qubits, we give these equations explicitly, considering both periodic and open boundary conditions. Using the classical theory of trace varieties and trace algebras, we explain the relationship between MPS and hidden Markov models and exploit this relationship to derive useful parameterizations of MPS. We present four conjectures on the identifiability of MPS parameters./nChapter 3 develops new parameters for use with directed acyclic graphical (DAG) models on discrete variables, which can simplify symbolic computations for tree models with hidden variables having more than two states. This development is the first step toward generalizing work of Smith and Zwiernik on binary trees, and makes it possible for some of the techniques used in Chapters 1 and 2 to be applied to graphical models with variables having more than two states.

Advisor: Sturmfels, Bernd
Essays on the Role of Leadership on Cooperation, Competition and the Consolidation of Power

We explore the association between leadership and economic success in three different settings. First, we offer a new approach to study how groups lacking formal leaders coordinate actions (e.g. innovation, corporate transformation, civil uprising, etc.). Using controlled laboratory experiments, we find that leadership is a critical catalyst for cooperation. By varying the payoffs for not cooperating when others do so, we identify an interaction effect between the characteristics of leaders and the underlying context in which leadership emerges. In particular, when these payoffs are low, leadership is ubiquitous: no special features distinguish leaders. When change requires overcoming high monetary incentives favoring the status quo, leaders tend to be exceptional. These types of leaders exhibit a distinct non monetary taste for mutual cooperation. This result implies that recruiting communally oriented individuals may facilitate innovation or change within firms. Next, we study the extent to which non-pecuniary motives explain collusive behavior and consequently low productivity in firms. We find that classical collusion, obtained by explicit or implicit agreements between individuals, is fueled by other-regarding concerns. Each member showing other regarding concerns decreases group effort by 15% of the average effort in a group of three individuals. Moreover, the emergence of a selfish leader from an originally leaderless group exacerbates this collusive behavior. Thus, the propensity of collusion is highest in a group of one selfish individual and two other regarding ones. Contrary to our first essay, leadership in this case is detrimental for productivity because/nof conflicting interests between the workers and the firm. Finally, we study how incumbents consolidate power over time. Using a formal theory model, we identify a mechanism by which leaders break away from the following trap: the more growth is fostered, the stronger the incentives for challengers to contest control. The mechanism hinges on two forms of investments by the incumbent: coercive capacity and productive capacity. In an application to state consolidation, we derive lessons for state-building by showing how investments in coercive capacity might have to precede investments in productive capabilities to ensure prosperity and peace. We also show how economic shocks and arms innovations may trigger state consolidation and economic take-off or keep polities in a trap of conflict and economic stagnation.

Advisor: Dal Bo, Ernesto
Morgan, John
A fourth-order adaptive mesh refinement solver for Maxwell's Equations

We present a fourth-order accurate, multilevel Maxwell solver, discretized/nin space with a finite volume approach and advanced in time with the/nclassical fourth-order Runge Kutta method (RK4). Electric fields are/ndecomposed into divergence-free and curl-free parts; we solve for the/ndivergence-free parts of Faraday's Law and the Amp\`ere-Maxwell Law/nwhile imposing Gauss' Laws as initial conditions. We employ a damping/nscheme inspired by the Advanced Weather Research and Forecasting/nModel to eliminate non-physical waves reflected off of coarse-fine/ngrid boundaries, and Kreiss-Oliger artificial dissipation to remove standing/nwave instabilities. Surprisingly, artificial dissipation appears to damp the/nspuriously reflected waves at least as effectively as the atmospheric/ncommunity's damping scheme.

Advisor: Colella, Phillip
Morse, Edward
The Carlson-Simpson Lemma in Reverse Mathematics

We examine the Carlson-Simpson Lemma (VW(k,l)), which is the combinatorial core of the Dual Ramsey Theorem, from the perspective of Reverse Mathematics. Our results include the following:/nWorking in the system BSigma_2^0, we carry out the construction of a failure of the ordered version of the Carlson-Simpson Lemma OVW(k,l), which was introduced in a paper by Miller and Solomon. This observation implies that we can construct such a recursive counterexample in the model of SRT_2^2 that was discussed in a recent paper by Chong, Slaman and Yang. It follows that SRT_2^2 does not prove OVW(k,l) over RCA_0./nWe also show that the strength of the principle VW(k,l) is independent of the number of colors l being used./nBy proving that VW(k,l) is not conservative over RCA_0 for arithmetical sentences, we conclude that VW(k,l) is not provable from any theory that is conservative over RCA_0 for arithmetical sentences.

Advisor: Slaman, Theodore
Biodiversity and Ecosystem Services in Agriculture: Evaluating the Influence of Floral Resource Provisioning on Biological Control of Erythroneura Leafhoppers (Hemiptera: Cicadellidae) and Planococcus Mealy Bugs (Hemiptera: Pseudococcidae) in California Vineyards

The research tested the natural enemies hypothesis in an attempt to explain why lower pest densities are observed in some diversified farming systems. The research evaluated the influence of floral resource provisioning (FRP) and chemical ecology strategies on biological control of Erythroneura leafhoppers (Hemiptera: Cicadellidae) and Planococcus mealybug (Hemiptera: Pseudococcidae) in California vineyards. Field and laboratory studies quantified the impacts on crop damage, pest and natural enemy abundance, and natural enemies fitness theorized to be enhanced through floral resource provisioning in agroecosystems. Multiple two-year studies measured the impact of intercropping three flowering ground covers, lacy phacelia (Phacelia tanacetifolia), bishop's weed (Ammi majus), and common carrot (Daucus carota) on biological control of leafhoppers and vine mealybug by the parasitoids Anagrus spp. (Hymenoptera: Mymaridae) and Anagyrus pseudococci (Hymenoptera: Encyrtidae). Using identical intercropping treatments, the research included three large scale and fully replicated research designs located in the central San Joaquin, the northern San Joaquin, and the Napa Valley of California. Laboratory studies quantified the impacts of FRP on the fitness of Anagyrus pseudococci, a key parasitoid natural enemy of vine mealybug. The central San Joaquin Valley field study measured the impact of FRP and pheromone based mating disruption on biological control of vine mealybug. The northern San Joaquin Valley field study measured the impact of FRP and methyl salicylate on biological control of Erythroneura leafhoppers. The Napa Valley field study measured the effect of methyl salicylate alone on biological control of Erythroneura leafhoppers.

Advisor: Altieri, Miguel A