VictorJuiz/thesis huggingface dataset:
Attosecond channel-coupling in molecular photoionization delays
Keywords: Applied Physics.

Molecular and chemical physics rely heavily on the use of approximations and simplifying models to deal with the complex reality of many-body electronic interactions. Although these models are essential, they have their limitations. One important area where simplifying models break down is in the examination of electronic channel-coupling. Photoionization channel-coupling is defined as mixing multiple continuum channels of the scattering photoelectron, caused by attosecond-scale multielectron interactions. Channel-coupling in photoionization is challenging to measure and model because it is a time-dependent phenomenon. Most models will simplify out the dynamic electronic environment, and experimental observables similarly cannot access the intermediate states at attosecond timescales. The photoionization time delay, an interferometric measurement of the group delay of the scattering electron wavepacket, offers a solution to this problem. Although it is not a time-dependent quantity, it is highly sensitive to the intermediate states and their interactions, since phase is accumulated throughout the entire half-scattering process of photoionization. This sensitivity can be leveraged to discriminate between models with various levels of electronic approximations, identifying the relevant electronic interactions and determining the correct level of detail needed to accurately describe the system. I measured the photoionization time delay in a variety of molecular systems that showcase different continuum channel-coupling phenomena. In each system, I show that analyzing the photoionization time delay in the context of models gives insight into the relevance of various interactions at the attosecond timescale. Through these experiments, I demonstrate that photoionization delays are an effective model discriminator for continuum channel-coupling induced by attosecond-scale electron interactions
Automatic interpretative seismic image-focusing analysis
Keywords: Geophysics.

The focusing of a seismic image is directly linked to the accuracy of the migration velocity model. Therefore, a critical step in a seismic imaging workflow is to perform a focusing analysis on a seismic image to determine errors within the migration velocity model. While the residual curvature information provided within the offset/angle axis is commonly used to assess velocity errors, the focusing within the physical (i.e., midpoint) axes of a seismic image is often neglected. This is due to the highly interpretative nature of the focusing of geological features within seismic images, therefore making focusing analysis within the physical space difficult to automate. In this dissertation, I present an automatic data-driven approach that makes use of a convolutional neural network (CNN) equipped with high-dimensional convolutional operators to automate seismic image-focusing analysis. Training the CNN on focused and unfocused geological faults within synthetic and real prestack seismic images, I demonstrate this approach can make use of both spatial and offset/angle focusing information to robustly estimate velocity errors within seismic images. To test effectiveness of the approach, I apply it to an unfocused 2D limited-aperture image from the Gulf of Mexico and an unfocused 3D image from the Dutch Sector of the North Sea and show that it can robustly estimate velocity errors in the presence of limited illumination and coherent noise. For both applications, I show that performing a refocusing correction using the estimated velocity errors leads to an improved focusing in the unfocused images and consequently, improves the automatic detection of the faults within the images
Avenues to miniaturize optical gyroscopes
Keywords: Physics.

This thesis studies different avenues to miniaturize fiber-optic gyroscopes for navigation applications. In particular, a gyro was built using a 5.8-mm radius ring resonator on a chip with a quality factor of 100 million by using ultra-low-loss silicon-nitride waveguides. A record angular random walk per unit area was set for on-chip optical gyroscopes in the literature. Methods for enhancing the Sagnac phase were also studied, in particular by using exceptional points and loss compensation. Although operation at an exceptional point provides an enormous enhancement in the Sagnac frequency splitting, no enhancement was found in rotation sensitivity or precision. However, a very large enhancement in rotation sensitivity (a factor of 2400) was predicted in a coupled-ring gyro with gain, thereby showing great promise as a new architecture for which to build much smaller gyros
Back on Track: Thailand's High-Speed Rail within China's Belt and Road Initiative
Keywords:  Stanford Global Studies
Belt and Road Initiative
China
East Asian Studies
High-Speed Rail
Public-Private Partnership
Stanford Global Studies
Thailand
Turkey
Text
Thesis

In 2013, President Xi Jinping unveiled his Belt and Road Initiative (BRI), a global development strategy involving infrastructure projects worth over one trillion USD. For the People’s Republic of China (PRC), opaque negotiations are the norm and result in deals that must use Chinese financing, Chinese workers, and Chinese materials, and in exchange, the host country receives infrastructure development. The “win-win” scenario provides countries that are short on technical expertise and financial resources the means to develop infrastructure and leaves the PRC obtaining a strategic resource. This study focuses on how Thailand broke away from high-speed rail (HSR) negotiations with China and forged a new path forward in BRI project implementation. Thailand is the first BRI country in which Beijing has permitted the host county to self-fund the project, train the host country's engineers, forgo the use of Chinese workers for local Thai contractors, utilize Thai materials, and transfer HSR technology to the host country. The study answers questions such as, why did the PRC make huge concessions to Thailand? How can middle-power countries develop agency in relation to China? What structural changes did Thailand implement in order to self-fund and assume control of a HSR project? And what lessons from this case can be extracted and used by other less powerful countries within BRI? The research method involves a qualitative approach that draws on open-source information from across the Thai government. The study coalesces and analyzes stove-piped information that contributes to the broader BRI literature that less powerful states can devise financial alternatives to lessen their reliance on Chinese financing.
Bacteriophage and antibacterial innate immunity in health and disease
Keywords: Microbiology and Immunology.

Bacteriophages—viruses produced by bacteria—are among the most abundant and well-studied organisms on earth. However, the phages within the human body are only beginning to be explored. Despite extensive explorations of other components of the microbiome, the human phageome—our endogenous bacteriophages—remains a scientific frontier. The phageome is only beginning to be characterized for many organs and disease states. Direct interactions between phages and human immune responses are similarly just beginning to be systematically investigated. Here, we explore the interplay between our endogenous phages and their interactions with the mammalian innate immune system during bacterial infection
Bad doctors, enablers, and the powerless : the United States opioid crisis and the redefining of help
Keywords: Sociology.

The contemporary opioid crisis has coincided with a notable shift towards more public-health-focused drug policies than in previous drug crises. Yet individuals struggling with addiction continue to be seen as responsible for the onset and persistence of their condition, and this blame can carry over to their families. These dynamics highlight the persistent tension between moral and medical discourses of addiction that permeate society. Drawing on data I collected through 65 in-depth interviews with current and former opioid users and their non-opioid using family members, my dissertation examines: 1) how they attempt to navigate this tension to treat or prevent drug addiction for those closest to them and 2) the impact these efforts have on their sense of self and well-being. In the first paper, I illustrate how concerns about "enabling" complicate family members' notions of help and create a morally fraught dilemma because it is unclear to them whether it is more harmful to provide or withhold support. Attempts to navigate this dilemma were often a source of guilt and anxiety. In the second paper, I examine the ways individuals who have struggled with addiction attempt to support others struggling with addiction and the benefits and challenges they encounter. For many, the ability to help others provided a positive boost in their self-esteem and played a crucial part in their identities as "recovered" users. However, focusing too much on helping others was considered problematic because it might distract a person from properly managing their recovery. In the third paper, I explore the ways parents who have struggled with drug addiction conceptualize their children's risk of addiction and the strategies they take to minimize those risks. I demonstrate how an emphasis on socialization as a driver for drug use and addiction created a space where some parents felt they could help minimize their children's risk of following in their footsteps, despite potential biological predispositions. Together, this dissertation's findings provide important insight on how conflicting cultural meanings surrounding addiction complicate the meaning of social support in ways that may contribute to the stigmatization and marginalization of people who use drugs and their families. They also have broader theoretical implications for understanding how ambiguity may strain identities and relationships, the benefits and risks associated with helping in the context of illness, and how conceptions of risk impact social support patterns and parenting strategies
Bakken ecology : the culture and space of fracked farmland in North Dakota
Keywords: Anthropology.

Farmland fracking shapes culture, space, and ecology in northwestern North Dakota's Bakken region. Oil company employees and officials, scientists and landowners collectively manage the socioecological uncertainties of juxtaposed agriculture and extractivism. This dissertation examines the politics of that public/private managerial process. Engaging political and environmental anthropology, I describe modern environmental politics in the Bakken as a reflection of Settler colonial ideals integral to the founding of the nation. Fracking in the Bakken is no imposition of, or victimization by, government and corporations. Instead, hydrocarbon commodification is a deeply personal practice through which people manage uncertainty according to colonial ideals for both space and ecology. Through that process, the people who live in and/or manage the Bakken come to define the modern environment according to colonial ideals for managing socioecological processes. Not just a product of conservative America, the politics of managing hydrocarbon commodification analyzed in this dissertation are evidenced across modern ecologies
Balancing Act: US Financial Diplomacy towards China’s Current Account Surplus, 2009-2013
Keywords: Center for International Security and Cooperation
International economic relations
Economic policy > International cooperation
China
Foreign exchange
Group of Twenty
United States. Department of the Treasury
Text
Thesis

The 2008 global financial crisis, the worst since the Great Depression, was viewed by the United States’ government as partially a consequence of China’s undervalued renminbi and export-reliant economic model. Despite intensive American engagement, these Chinese policy choices bred a current account surplus and ballooning global imbalances. While regulatory missteps most directly spawned the crisis, imbalances were seen as inflating the bubble. After the crisis, US policymakers prioritized addressing China’s surplus via financial diplomacy. This thesis analyzes how and why US policymakers engaged with China, and to what degree this diplomacy was effective. It builds a detailed diplomatic history of the 2009-2013 period, coinciding with the first term of the Obama administration and main period of post-crisis diplomacy. This history is derived from speeches, communiques, and other official communications from the bilateral Strategic & Economic Dialogues and multilateral G20 summits, as well as other public Treasury Department statements, Chinese government documents, and media reports. The official history is supplemented with interviews with key US policymakers. Based on this data, I draw three main conclusions. First, US diplomats were sensitive to China’s internal politics. By building on the arguments of Chinese groups aligned with US aims, negotiators leveraged China’s ‘two-level game.’ In essence, American pressure was used by Chinese technocrats as leverage in domestic battles over reform. Additionally, US officials kept many elements of diplomacy private to ensure China’s leaders could save face by claiming reform was based on self-interest, not external pressure. Second, the US used the G20 to legitimize and broaden the rebalancing agenda while building multilateral pressure on China, though it could not construct a sustained coalition due to European unwillingness to pressure China. Third, while substantive reform arguments were most important, US negotiators used bilateral concessions as leverage, while also pursuing China-favorable reforms at the IMF to build trust. These bargaining chips were strengthened by the threat of Congressional protectionism. Overall, my thesis suggests that Chinese interests, not American pressure, drove most key reforms. However, strategic US engagement played an important role in facilitating change within China, providing a model for future financial diplomacy.
Baleen whale physiology revealed through the integration of bio-logging and ecoinformatics
Keywords: Biology.

Ecology is in the process of becoming "big data" scientific discipline, but development and adoption of infrastructure has been patchy. From community science to automated sensor networks, ecologists are collecting, aggregating, and analyzing more data than ever before. Among these new data sources are bio-loggers: animal-borne sensor packages that track location, behavior, physiology, and more. With hardware advancements in the last few decades, the data from these devices increased in quantity and complexity beyond the technical capacity of many ecologists. This challenge is particularly visible in physio-logging (the use of bio-loggers for observing physiology), which frequently employs a more diverse suite of sensors than other bio-logger applications. Therefore, physio-logging provides a compelling case study for developing ecological informatics infrastructure. This dissertation identifies the informatics gaps in physio-logging, demonstrates methodological advancements possible with greater infrastructure, and applies physio-logging data to a conservation framework. In Chapter 1, I offer a perspective on how the lack of informatics infrastructure stifles innovation. By looking to other scientific disciplines for inspiration, I describe how a greater emphasis on computational reproducibility could fuel collaboration and discovery. Chapters 2 and 3 build on the themes of infrastructure and innovation by providing examples of new physio-logging analytical methods. Finally, Chapter 4 uses bio-logging data to model the physiological consequences of anthropogenic disturbance to vulnerable cetacean populations
Ballots & Bullets: Understanding the Conditions that Facilitated Hybrid Actor Participation in Elections in Iraq and Lebanon
Keywords: Center for International Security and Cooperation
Lebanon
Iraq
Elections
Political participation
Text
Thesis

Hezbollah’s transition to parliamentary politics spurned the term “Hezbollah model,” but it is far from the only hybrid actor to hold seats in a national government. What are the conditions that facilitate hybrid actor participation in national elections? This thesis takes a qualitative approach to understand the interplay of these conditions for Hezbollah in Lebanon and the Sadrist movement in Iraq. The thesis makes a probabilistic argument about the presence and significance of four conditions: government tolerance, a supportive constituency, power vacuum, and foreign involvement.
Hybrid actor electoral participation has important implications for policymakers who are interested in preventing these actors from integrating with state governments, and in slowing the spread of Iranian influence in the Middle East, as Iran has had the most success in cultivating mutually beneficial relationships with hybrid actors in the region. Specifically, understanding the conditions that precipitate participation in elections opens the door to preventive measures in other countries in which hybrid actors flourish but have yet to enter into politics.
Basal hydrology under Totten Glacier after the GlaDS model and a Potential Transition Zone
Keywords: Glaciology
Geophysics
Antarctica > East Antarctica
Text
Thesis

The Aurora Subglacial Basin (ASB) in East Antarctica contains at least 3.5 meters of eustatic sea level potential in ice grounded below sea level, primarily draining through Totten Glacier into the Sabrina Coast. Totten’s coastal grounded ice has been thinning faster than any other glacier system in East Antarctica since the beginning of the satellite altimetry record and its grounding line has been retreating since at least 1996. Recent work has shown that a vast subglacial hydrological system underlies the Totten Glacier Catchment, likely providing important controls on ice dynamics. Ice-flow acceleration is directly linked to the distribution of subglacial hydrology; for example, a channelized or otherwise centralized hydrological system streamlines water loss without increasing basal lubrication, while distributed systems can increase lubrication and therefore ice flow. To predict the future behavior of this sensitive area, we must improve our understanding of the characteristics of the subglacial flow. Recent work applying the Glacier Drainage System (GlaDS) model applied to the ASB revealed a varied hydrological system beneath the Totten Glacier Catchment with channelization occurring within 200 km of the Totten grounding line. While the model provides a compelling picture of the glacier, the ice-penetrating radar survey coverage available at the time was not optimized for testing for the presence or absence of water in the modeled locations. Using newly-acquired aerogeophysical data, we provide a systematic comparison of inferred basal character and the modeled hydrological setting to test for a transition from a distributed to concentrated water system upstream of Totten’s grounding line. With these new data, we provide an updated picture of the subglacial system beneath Totten Glacier.
Basement membrane invasion during breast cancer
Keywords: Bioengineering.

In epithelial cancers, cells must invade through basement membranes (BMs) to metastasize. The BM, a thin layer of extracellular matrix (ECM) underlying epithelial and endothelial tissues, is primarily composed of laminin and collagen IV and serves as a structural barrier to cancer cell invasion, intravasation, and extravasation. Bm invasion has been thought to require protease degradation since cells, which are typically on the order of 10um in size, are too large to squeeze through the nanometer-scale pores of the BM. However, recent studies point toward a more complex picture, with physical forces generated by cancer cells facilitating protease-independent BM invasion. In this dissertation, I present work studying the impact of ECM mechanics on cancer cell invasion of the BM during breast cancer progression. Specifically, I will present work investigating the impact of ECM stiffness on the ability of cancer cells to form invadopodia protrusions in three-dimensional (3D) BM-like matrices. We show that increased stiffness of BM-like matrices diminishes invadopodia protrusion formation and cancer cell migration, contrasting the results from traditional 2D culture studies. Additionally, I will discuss my work on the development of a 3D in vitro model of collective invasion through endogenously produced BM. We find that cells utilize both proteases and forces to invade through the BM collectively. We also show that cells rely on volume expansion and contractility to exert pulling forces on the BM during invasion. These results reveal new mechanisms underlying breast cancer invasion and may lead to new strategies to inhibiting BM invasion. Ultimately, a comprehensive understanding of the diverse modes of BM invasion may yield new strategies for blocking cancer progression and metastasis
Battlegrounds to Bipartisanship: The Effect of Military Experience on Bipartisanship in the U.S. Congress
Keywords: Center for International Security and Cooperation
United States. Congress
Veterans
Partisanship
Text
Thesis

The U.S. Congress has become increasingly polarized over the last few decades, at times struggling to move past partisan divides to pass legislation, ultimately leading to little public trust in the institution. Meanwhile, for years, polling of the American public has shown the U.S. military to be among the most trusted institutions. Military service is often considered a crucial part of an individual’s identity. It is commonly cited to lend credibility to public figures’ published opinions and can serve as a major part of the platform on which veterans run for elected offices. Existing literature finds that military experience does impact mindsets on ideological issues such as defense budget and use of force, but the literature often fails to distinguish between relevant types of military service, such as branch, length, generation, and component. This thesis considers the effect of military experience, including various differentiators of that service, on bipartisanship in Congress. I collect data on the military background of Congress Members from 1991-2021, and I find that military service does correlate with higher bipartisanship or less partisanship, as measured in roll-call voting, bill sponsorship, and rhetoric. Length of military service and other differentiators, however, do not have a significant effect. I posit, therefore, that this increase in bipartisanship is due to self-selection and not socialization. Rather than any values learned from the military leading to bipartisanship, patriotism may prompt some to enter both the military and then Congress, as they serve their country through problem-solving that often necessitates bipartisanship. This finding highlights the importance of encouraging a strong national identity if we are to uphold a functional and flourishing democracy.