VictorJuiz/thesis huggingface dataset:
The chemistry, kinetics, and implications of oxygen defects in Li-excess oxides
Keywords: Materials Science and Engineering.

Li-excess layered oxides are a promising class of positive electrode materials with the potential to simultaneously improve both the energy density and cost of Li-ion battery systems. However, these materials suffer from several adverse electrochemical properties resulting from a host structure that becomes unstable at low lithium contents. In this dissertation, a comprehensive view of the role of oxygen defects in Li-excess oxides will be developed. First, the coupling of oxygen and lithium defects will be rationalized from thermodynamic principles. Using X-ray spectroscopy and ptychography, the continuous loss of oxygen from Li-excess materials over cycling will then be demonstrated. Surprisingly, a variety of characterization techniques indicate that the oxygen-deficient bulk structure contains persistent oxygen vacancies, offering a unified framework for understanding previous observations of transition metal reduction and cation disordering with cycling. I will then investigate other factors which affect the oxygen release process, including the lithium content and the particle morphology. Overall, the results presented in this dissertation inform the design and utilization of Li-excess oxides and illuminate promising chemical, structural, and morphological approaches for mitigating oxygen release in layered oxide materials
China’s Evolving Taiwan Policy: Bargaining on the Brink and Elite Threat Perceptions
Keywords:  Center for East Asian Studies
East Asian Studies, China, Taiwan, Policy
Text
Thesis

This paper assesses change and continuity in China’s Taiwan policy since the 17th century. Using policy documents, speeches, newspapers, and secondary sources as evidence, it advances the hypothesis China’s policy towards Taiwan is an evolving function of elite threat perception and military capabilities relative to other international actors. Case studies include the Qing’s decision to invade the island, the Qing’s response to Japanese occupation of Taiwan in 1874, Mao’s changing Taiwan policy in the 1950’s, Deng’s outlook toward Taiwan, and policy post-1989.
Chinese Fintech Companies And Their “Going Out” Strategies
Keywords:  Stanford Global Studies
Stanford
CEAS
China
Fintech
Innovation
Technology
Thesis

In the late 1990s, Chinese President Jiang Zemin launched the strategy of Chinese companies’ “Going Out” into foreign markets as part of China’s “Opening-up and Reform.” These companies were largely state-owned enterprises (SOEs) and generally concentrated in the primary industry. Fast forward three decades and China is arguably undergoing a new form of “Going Out,” albeit of a different nature. This current phase is largely a bottom-up and private-led movement, driven by China’s most rapidly growing and innovative companies—its private technology companies. This paper outlines the ascendance of China’s fintech companies, primarily Ant Group and Tencent, since their incipience in the early 2000s. It analyzes these companies’ motivations and strategies for global expansion and considers their current and prospective influence on financial digitization across the globe. Finally, it assesses the distinct opportunities and challenges that China’s fintech companies face—both domestically and abroad—as they strive to grow up and go out.
Chinese Influence in South America: Dimensions of Power in Argentina and Chile
Keywords: China
Latin America
Chile
Argentina
Thesis

How does China attempt to wield influence in South America? China's economic and political influence has risen rapidly over the past decade. Beijing's growing power has taken overt forms like its rising stature in international institutions, as well as more subtle forms in the media and legislatures of countries all over the world. This thesis analyzes several country case studies to assess how Beijing is exercising power in South America. More broadly, it illuminates how China’s hard, sharp, and soft power can interact as mechanisms of control. I find that China has consistently used coercive and manipulative tactics to build its influence abroad. These findings can help inform policymakers who seek to understand how China is actively expanding its global influence, particularly in those countries with which it has significant trading relationships.
Chinese Investment Strategy Across Latin America
Keywords:  Center for International Security and Cooperation
Center for International Security and Cooperation
Stanford University
Freeman Spogli Institute
Thesis

Why do certain Latin American countries receive substantially more Chinese investment than others? Since 2005, the People’s Republic of China’s investment in Latin America has grown, as evidenced by its upward trend of investment with the region now receiving nearly 10% of total Chinese investment, or $200bn. Scholars, analysts, and policymakers argue that growing Chinese investments, notably ones from its Belt and Road Initiative, are intended for global influence through corruption and debt diplomacy. Using the American Enterprise Institute’s China Global Investment Tracker, this thesis assesses the conventional wisdom by identifying the drivers of Chinese investment across Latin American nations. Specifically, it explains why Argentina, Brazil, Ecuador, Peru, and Venezuela receive high levels of Chinese investment compared to regional peers like Colombia and Mexico. The data suggests that Latin American corruption is not an influential factor in Chinese investment destinations, instead, the potential for commodity exports like soybeans, petroleum, and copper appears more important. The United States government must understand that Beijing’s intentions in the region – which are geared around securing commodity exports – and compete accordingly rather than maligning the PRC’s actions in Latin America without providing a competitive alternative.
Circuit techniques for compact and lightweight high-voltage DC power supplies
Keywords: Electrical Engineering.

High voltage power supplies are essential in scientific, medical, environmental, security, and robotics fields. The size and weight of the circuit often limit the portability of the system and the range of applications. Smaller, faster, and more efficient power supplies will enable new scientific and commercial advances. My thesis presents circuit techniques to improve the performance of high voltage dc generators. A traditional way of generating a high dc voltage involves a step-up transformer built with a bulky magnetic core and a Cockcroft-Walton voltage multiplier, assembled on an FR4 printed circuit board and sometimes potted in insulating epoxy. Recently, many advances are being made in wide-bandgap semiconductor devices, sub-millimeter size passive components, and high-frequency circuit design methodologies. Those technological developments enable new techniques to design a high voltage power supply. This dissertation presents several new ways to build a high voltage dc generator: a planar PCB transformer that simplifies high-voltage isolation transformer design, a new voltage multiplier topology that exhibits less output voltage drop than the traditional Cockcroft-Walton multiplier, and foldable converters assembled on a flexible PCB to miniaturize kilovolts-level power supplies down to the sub-centimeter scale. My dissertation includes the motivation for investigating each of those circuit techniques and relevant power supply designs as well as application examples. I experimentally validate that by using those techniques appropriately, one can build a smaller and lighter power supply that exceeds traditional boundaries of high voltage generator performance
A cis-regulatory lexicon of DNA motif combinations mediating cell type-specific gene regulation
Keywords: Genetics.

The role of the DNA sequence in protein-coding genes has been widely established due to the obvious functional relevance and well-defined relationships between DNA variation and protein sequence. However, most disease-associated variants are not in protein-coding sequences. This has led to much investigation of non-coding variation as it relates to protein-coding gene regulation. Critically, non-coding regulatory elements within DNA are intricately linked to cell type-specific protein-coding gene expression. This dissertation contributes to the goal of uncovering the underlying cis-regulatory logic of non-coding DNA sequences driving cell type-specific gene expression in homeostasis and disease. Cell type-specific non-coding cis-regulatory elements are known to drive important gene expression programs. However, it is still unclear what combinatorial DNA sequences underlie cell type-specific gene regulatory mechanisms. The objective of this dissertation is to progress our understanding of cis-regulatory logic through integration of genome-wide regulatory maps followed by modeling of combinatorial DNA motif logic in cis-regulatory modules regulating cell type-specific gene expression programs and focused identification of functional regulatory DNA motif combinations (DMCs) in homeostasis and complex disease. In Chapter 2, I generate epigenomic and transcriptomic profiles of 15 primary human cell types and perform integrated analysis to define cell type-specific open chromatin peak-long range looped-expressed target gene transcripts (PLTs). I then incorporate disease-associated single nucleotide variants (SNVs) from the NHGRI GWAS catalog and Genotype-Tissue Expression (GTEx) data to link SNVs enriched in cell type-specific PLTs to putative target genes. In Chapter 3, I model the genomic information necessary to derive cis-regulatory modules linked to cell type-specific gene expression programs and nominate transcription factor (TF) DMCs underlying cell type-specific regulatory logic. Finally, in Chapter 4, I validate DMC logic in four primary human cell types and identify cancer-specific regulatory logic in human squamous cell carcinoma and melanoma cells. The findings and approaches described in this dissertation add to the existing annotation of functional combinatorial TF motif logic and help build a framework for future studies of cis-regulatory logic
Close-microphone cross-talk cancellation in ensemble recordings with statistical estimation
Keywords: Music.

While recording an ensemble of musicians, microphone cross-talk, or "bleed", is considered a nuisance by audio engineers. When two microphones pick up the same signal with a time delay, comb filtering artifacts are present. An expensive solution to the microphone bleed problem is to use acoustic isolation panels between musicians. Obviously, this is not feasible in a live setting. Simpler solutions include using directional microphones with specific polar patterns to pick up radiation from a desired direction and using the close-miking technique where microphones are placed at a distance of 5 - 50 cm from the sound source. Interference can become significant in such cases due to the effect of nearby strong reflective surfaces. The complexity lies in the fact that there is usually an arbitrary number and distribution of instruments and microphones, and results are influenced by the room acoustics of the studio where the ensemble is recorded. In this thesis, I propose statistically optimal estimators to cancel microphone bleed offline in the mixing and production stage. First, a calibration stage is proposed, where one instrument is played at a time and recorded by all the microphones. This single-input, multiple-output (SIMO) system is used to estimate an approximate relative transfer function matrix, which represents the acoustic path from each source to each microphone and encodes the room response, as well as the mic directivity and source radiation patterns. A convex cost function is derived in the time-frequency domain that simultaneously optimizes the sources and the relative transfer function matrix, which is assumed to be time-invariant. It is shown that minimizing this cost function gives the Maximum Likelihood (ML) estimate when the microphone signals are assumed to be normally distributed. The ML estimator is extended to include apriori statistics of the sources, and the Maximum Aposteriori Probability (MAP) estimator is derived. The proposed methods are evaluated against a state-of-the-art Multichannel Wiener Filter based algorithm on a simulated dataset of string quartet recordings in a shoebox room, and on a drum-kit recorded in the CCRMA recording studio. The results show that cross-talk cancellation is achieved while maintaining the perceptual quality of the separated sources
A collaborative bioarchaeology of African diaspora and enslavement in colonia Cañete, Peru
Keywords: Anthropology.

In 2009, the Peruvian government apologized to its citizens of African descent for the exclusion enacted against them from the colonial period to the present. While this gesture initiated a long-awaited process of addressing the history of enslavement and its lasting impacts for Afro-descendant communities, it has yet to be translated into meaningful reform. Afro-Peruvian histories—including histories of captivity, exploitation, and racialized violence—continue to be largely absent in academic curricula and public discourse. Such silencing has direct implications on contemporary sociopolitics in Peru, as Afro-Peruvian communities continue to face structural inequalities and marginalization in their everyday lives. This dissertation addresses these issues by considering how community-engaged archaeology can serve as both a tool to cultivate a closer understanding of histories of African enslavement in Peru, and a space where descendant communities can pursue a politics of belonging in contemporary scholarship and heritage discourse. As a case study, it focuses on research at Hacienda La Quebrada (1741-1849), a historic sugar plantation in the central coastal valley of Cañete, Peru. Through bioarchaeological, historical, and ethnographic work at the former plantation and in the communities that live around the site today, this project asks: What were the everyday conditions of living for enslaved Africans and Afro-descendants at La Quebrada, and how did these conditions shape their overall life-histories? How do members of the local descendant community and other Afro-Peruvian stakeholders in the region remember and relate to these histories? Finally, how can the findings of interdisciplinary archaeological research contribute to efforts to revalorize African diaspora histories and cultural heritage in Cañete today? By addressing these questions, this dissertation demonstrates how community-engaged archaeology can work to confront the subalternization of African descendant communities in hegemonic narratives of history, heritage, and national identity. Its collaborative approach to studying the lived experiences of enslavement shows how archaeology can critically address histories of colonial violence while simultaneously reinforcing empowering narratives that foreground the contributions of African descended peoples to Peruvian society and culture. At the same time, by empowering communities to study and retell their pasts in accordance with their own worldviews, and by working together to commemorate these histories through public heritage work, this project ultimately contributes to larger efforts for recognition, inclusivity, and the pursuit of community rights in Peruvian archaeology
Collaborative innovation : the antecedents, consequences, and valuation of technological resource contributions
Keywords: Management Science and Engineering.

The innovation performance of entrepreneurial ventures critically depends upon their management of internal and external relationships. Within organizational boundaries, how cofounders collectively contribute resources and efforts can significantly impact the process of technological ideation and commercialization. Beyond organizational boundaries, how entrepreneurial ventures manage their external relationships with partners, such as product users, is also vital for innovation and overall performance. Across three inter-linked papers, this dissertation investigates collaborative innovation both within and beyond the organizational boundary of entrepreneurial ventures, focusing on the antecedents, consequences, as well as valuation of technological resource contributions. Using a quasi-natural experiment, the first paper examines how innovation-driven collaborations between ventures and their product users can be undermined by legitimacy concerns stemming from another domain within the multiplex relationship between the two parties. The second paper analyzes the organizational consequences of venture-user collaborations and suggests heterogeneous effects on different types of successes (initial public offering vs. acquisitions). Finally, the third paper explores how the type of resources contributed (technological vs. non-technological) shapes initial equity share division among cofounders as well as equity dilution over time. Together, this dissertation contributes to the literature on interorganizational relationships, innovation, and entrepreneurship and provides policy implications
Collective action, collective hopes : cross-cultural resource management in Aotearoa New Zealand's Mātaitai fishing reserves
Keywords: Anthropology.

This dissertation explores how cross-cultural resource management efforts incorporate disparate ontologies, using the mātaitai reserves (customary fishing reserves) in the Mahia Peninsula of Aotearoa New Zealand as a case study. Here, indigenous Māori and government stakeholders work together to manage these reserves in a manner that respects indigenous worldviews and encourages sustainable ocean harvesting. The potential for collective action in this context is affected by ontological assumptions, legibility practices, and the affective power of hope
Colloidal nanoparticle catalysts for sustainable energy applications
Keywords: Chemical Engineering.

Rising greenhouse gas emissions drive climate change causing catastrophic consequences such as reduced crop yields and adverse weather disasters. Avoiding these climate outcomes requires development of technologies for both emission control, to convert pollutant gases such as carbon monoxide (CO) and hydrocarbons (HCs) into less harmful carbon dioxide (CO2), and CO2 conversion into useful products. The first part of my talk focuses on stable and active catalysts for exhaust emission control to eliminate the discharge of noxious gases from transport vehicles operating on fossil fuels. Platinum (Pt) and palladium (Pd) are excellent at combusting CO and HCs into CO2, but unable to maintain high performance under harsh conditions. Initially small PdPt nanoparticles (NPs) agglomerate into large crystallites with reduced surface area and, thus, lose their effectiveness. To prevent these metals from deactivation, I have developed a nanocasting strategy to encapsulate PdPt NPs inside alumina. Here, I embed the metal NPs inside a polymer, infiltrate the metal-polymer composite with an aluminum precursor, and calcine the resulting material to get the metal NPs distributed inside alumina. Such NPs demonstrate unprecedented stability by maintaining high rates for hydrocarbon combustion in the harshest operating environment the catalysts could be subjected to, thus surpassing state-of-the-art emission control materials. The second part of my talk is on developing catalysts for CO2 conversion into fuels and chemicals, by reacting CO2 with hydrogen. This reaction is not applied on a large-scale due to several challenges, including poor selectivity: instead of forming one desired product, the reaction forms a wide range of species, making a separation process prohibitively expensive. Overcoming this barrier requires identifying what specific sites on a catalyst surface are responsible for different products - given that the catalysts change under reaction conditions -- and designing catalysts with desirable properties. To this end, I make materials with controlled size, shape, and composition and track changes in their structure using X-ray absorption spectroscopy. Overall, my research efforts are focused on engineering catalysts for zero greenhouse gas emission energy technologies
Colloidal physics modeling of biomolecular behavior to enable cell building
Keywords: Bioengineering.

Building cells from scratch requires understanding how molecules -- the building blocks of cells -- move and interact to produce behavior. To better address this challenge I apply colloidal physics -- how microscopic particles behave in liquids -- to cell biology, leveraging protein synthesis as a model process. Specifically, I develop a modeling framework for representing the physical motion and chemical reactions of individual molecules in the full context of crowded cytoplasm, showing how individual tRNA and ribosomes diffuse and interact to enable protein synthesis. Using my framework, I elucidate a putative mechanism underlying how ribosomes become more productive in faster growing cells, an experimental observation that has remained unexplained for 50 years. Specifically, I show that the nucleoid-excluded cytoplasm, where translation primarily occurs, becomes three times more packed with molecules in faster growing cells. While increased packing slows molecular movement down, molecules also become closer together, a general phenomenon that enables matching tRNA and ribosomes to find each other more quickly and thus speeds up protein synthesis. I then explore the expected properties of cytoplasm for hypothetical cells that grow faster than ever observed. I predict that further increases in crowding would provide diminishing returns for or hinder protein synthesis, suggesting a physical limit on growth rate. Finally, I extend colloidal physics modeling directly to the design of synthetic cells by calculating how the relative abundances of tRNA can be engineered to provide optimal protein synthesis strategies for both wild-type and codon-reduced genomes. Engineered tRNA abundances are predicted to enable up to ~20% faster and ~50% slower protein synthesis compared to natural abundances. Colloidal physics modeling and engineering can be expanded across cell types and processes, supporting the general design and construction of cells
Colonial Care: Exploring How a Potential Funding Increase Could Improve Puerto Rico’s Medicaid Program and Health Care System
Keywords: Puerto Rico
Medicaid
FMAP
Affordable Care Act
Medicaid expansion
physician retention
health care
health outcomes
Thesis

This thesis analyzes the potential impact of raising the Medicaid Federal Medical Assistance Percentage rate for Puerto Rico on the island’s health system. It begins with an historical overview of the Medicaid program in Puerto Rico and of problems related to program administration and funding, both of which differ substantially from Medicaid in the mainland United States. It then compares the effects of the Affordable Care Act’s Medicaid expansion in Puerto Rico to what occurred in the rest of the United States and analyzes relevant literature pertaining to the benefits of Medicaid expansion on the mainland. The use of block grant funding for Puerto Rico, as opposed to a full Medicaid expansion, resulted in the island experiencing fewer benefits than its state counterparts. Based on an original analysis of publicly reported data on healthcare utilization and health outcomes in Puerto Rico, and application of an evaluative framework adapted from other health policy analyses, the thesis concludes that the funding mechanism for Puerto Rico’s Medicaid program should be altered to match that of the rest of the United States.