VictorJuiz/thesis huggingface dataset:
The Influence of Development on Habitat Fragmentation, Animal Behavior and Movement

Protecting ecosystems, corridors, and working landscapes is critical to addressing rapid global change. Given the pervasiveness of the human footprint, managers and policy-makers often seek a clearer picture of how development affects habitat conservation and species persistence. This dissertation used a combination of remote sensing, data synthesis, and empirical data collection to examine how protected areas have been impacted by development within and beyond their borders, as well as how terrestrial species have behaviorally responded to anthropogenic features in altered landscapes. This work measured ecosystem change spanning three scales, from global protected areas, to community-level ecological interactions, to individual-level change in animal behavior./nHabitat connectivity between protected areas and surrounding land influences protected area effectiveness. More isolated protected areas often exhibit reduced species movement, dispersal, and genetic diversity, resulting in wildlife decline. To quantify protected area isolation globally, in Chapter 2, I developed a habitat-edge detection approach to measure change between protected areas and surrounding land over time. I found a significant 20-year loss in habitat continuity along the borders of the world’s largest protected areas — the strongest evidence to date that protected areas have begun to resemble habitat islands in a human-dominated world. While habitat discontinuity may have negatively affected wild animals by disrupting patterns of movement or behavior, others may have used human-altered environments to gain resources or safety, with each type of response resulting in distinct outcomes for species interactions and wildlife persistence. In Chapter 3, I delved into this topic with a framework I used to examine the behavioral effects of human activity on 178 predator-prey pairs from published camera trap studies. I found four primary patterns of predator-prey response to people, highlighting the context-dependency of development on species interactions. While some wildlife species likely displayed a consistent behavioral response to disturbance, many species may have adjusted their behavior based on the level, frequency, or length of exposure to disturbance. To measure how behaviorally flexible species navigate landscapes with both development and natural features, in Chapter 4, I evaluated coyote (Canis latrans) habitat selection in a mixed-use agricultural landscape. I found that coyotes avoided development, but selected for roads and agricultural areas despite possible persecution and conflict. This study revealed a few of the risks, rewards, and tradeoffs that behaviorally plastic carnivores face in developed landscapes. To conclude, I summarize the conservation implications of this research, and call for incorporating the social, economic, and political drivers of land-use into wildlife ecology to promote effective and socially-conscious conservation into the future.

Advisor: Brashares, Justin
Generative Models for Image and Long Video Synthesis

In this thesis, I present essential ingredients for making image and video generative models useful for general visual content creation through three contributions. First, I will present research on long video generation. This work proposes a network architecture and training paradigm that enables learning long-term temporal patterns from videos, a key challenge to advancing video generation from short clips to longer-form coherent videos. Next, I will present research on generating images of scenes conditioned on human poses. This work showcases the ability of generative models to represent relationships between humans and their environments, and emphasizes the importance of learning from large and complex datasets of daily human activity. Lastly, I will present a method for teaching generative models to follow image editing instructions by combining the abilities of large language models and text-to-image models to create supervised training data. Following instructions is an important step that will allow generative models of visual data to become more helpful to people. Together these works advance the capabilities of generative models for synthesizing images and long videos.

Advisor: Efros, Alexei A
Structure-Driven Algorithm Design in Optimization and Machine Learning

A textbook property of optimization algorithms is their ability to solve the problems under generic regularity conditions. Two examples are simplex method and gradient descent (GD) method. However, the performance of these fundamental and general-purpose optimization algorithms is often unsatisfactory; they often run slowly and perhaps return the suboptimal solutions in generic settings. In my view, this is the price of their generality; indeed, the generic algorithms are an achievement, but for many problems, the gains from leveraging spe- cial structure can be huge. A basic question then arises: how can we harness problem-specific structure within our algorithms to obtain fast, practical algorithms with strong performance guarantees? As more structured data-driven decision-making models emerge, this question has become increasingly pressing and relevant to practitioners./nFor example, the GD is known to get stuck at a suboptimal saddle points in nonconvex optimization. Nonetheless, a line of recent works have shown that random initialization or perturbation changes the dynamics of GD and makes it provably converge to a global optimal solution. In addition, both Markov decision process (MDP) and discrete optimal transport (OT) problems can be solved using large-scale linear programs. Rather than using generic LP algorithms, the policy iteration and the Sinkhorn iteration exploit special structures in MDP and OT and thus perform better in practice. Adapting algorithms to problem-specific structure is generally referred to as structure-driven algorithm design./nAlthough this line of research – which has been studied extensively for over 70 years – has enjoyed widespread success, the machine-learning success stories have introduced new formulations ripe for deep theoretical analysis and remarkable practical impact. My research pushes this frontier by identifying special structure of reliable machine learning (minimax optimization) and multi-agent machine learning (high-order optimization and beyond) and design optimal algorithms for computing the appropriately defined optimal solutions; and other structured problems, such as efficient entropic regularized optimal transport, gradient- free nonsmooth nonconvex optimization, and adaptive and doubly optimal learning in games.

Advisor: Jordan, Michael I
Closed Loop Investigation of Hippocampal Replay

How people absorb and recall information about the world around them remains a central mystery of neuroscience. One popular framework for studying this process, systems consolidation, describes how episodic memories are initially encoded during an experience, consolidated into long term memory afterward, and recalled later. Each of these processes has been mapped to specific types of neural activity in specific brain regions. This mapping is incomplete. New progress each year reveals more details about how our memory system functions and new insights into the neural activity of our brains. One such type of neural activity is replay events. These events, typically investigated in rodent brains, allow an animal to simulate paths through an environment. A large body of research has shown clear connections between replay events and the consolidation phase of systems consolidation./nThis dissertation expands on this research in two ways. In my behavioral results, I describe a series of experiments which suggest that replay may be critical for all three parts of systems consolidation, including the encoding, consolidation, and recall phases. In these experiments, we interfere with the rats’ ability to generate replay events and observe a corresponding loss of memory for salient locations in an environment. These experiments employ closed-loop methods to interact with ongoing neural activity in real time, by delivering feedback whenever a replay event occurs. In my other chapter, I present a tool designed to greatly expand what experiments are possible in such closed-loop interactions. While most interactions involve either detection of all replay events or some coarse categorization, this tool allows experimenters to read out the simulated path through the environment directly as the replay event is occurring.

Advisor: Foster, David
Which Streets are Complete? Mapping Pedestrian, Transit, and Cycling Infrastructure at Scale in San Francisco, CA

Contemporary American streets are dominated by the automobile, both its movement and storage, which took root in the early 20th century and has been supported by transportation planners in the decades since. Pedestrian fatalities remain stubbornly high – even in cities with “Vision Zero” goals – and cars generate significant levels of both local air pollution and globally-relevant greenhouse gasses. Moreover, the default use of curbside lanes as on-street parking precludes a number of other street designs, such as wider sidewalks, protected bike lanes, transit bulbs and islands, parklets, rain gardens, and street trees. This dissertation probes these long-standing and consequential street layouts with methods that are both highly granular (accurate to the block level), and at the same time, comprehensive to an entire municipality. San Francisco, California, a dense, high-income, and nominally “progressive” American city serves as the case for three separate analyses: an in-person census of roughly 3,000 municipal bus stops, and review of satellite-imagery of nearly 6,400 intersections for the presence or absence of marked crosswalks, and the provision of on-street parking and its obstruction of a growing bike-lane network. Chapter 1 demonstrates that crosswalk provision varies dramatically across San Francisco, from Census tracts with 100% of intersections exhibiting marked crosswalks, to others with less than 10% coverage. Chapter 2 entails the largest bus-stop census of its kind, covering the entire SFMTA system. This approach finds that one third of all bus stops are blocked by on-street parking, and two thirds lack seating of any kind, as well as spatial clusters of stop amenities. Indeed, both high-quality bus stops and marked crosswalks are present to a far greater extent in the city’s northern half, unexplained fully by transit service, density, or pedestrian volumes. Lastly, Chapter 3 identifies fifty miles of angled parking in San Francisco, a format that roughly doubles on-street parking capacity, and decreases the opportunity for high-quality bicycle lanes. These studies provide both salient datasets to guide San Francisco’s street improvements (of which some progress at City Hall has already occurred), and serve as proof of concepts for planners and researchers elsewhere to probe their own blocks granularly and at scale. Indeed, this dissertation demonstrates new frontiers in applied urban analytics, and broadens and challenges the academic literature on transportation equity. It does so by expanding the types of street elements to be spatialized across neighborhoods, and demonstrates how the provision of seemingly-mundane features such as bus stops, crosswalks, and on-street parking can mirror (and exacerbate) other long-running investment disparities.

Advisor: Chatman, Daniel G.
The Body Migrant: Border militarization in Mexico and the changing migrant body

This text is an ethnographic and anthropological investigation into migrant bodily experience in Mexico, especially Central American migrant experience. It seeks to provide a new way of understanding border militarization and migrant il/legalization and racialization through the instantiation of new techniques of bodily control. I analyze a previously understudied, anti-immigration policy in Mexico known as the Southern Border Program, which has quietly detained and deported millions of (mostly Central American) migrants traveling through the country. Likely tens of thousands of migrants are injured each year as they try to traverse Mexico’s new militarized borders, and I seek to document the ethnic, racial, and health disparities that structure migrants’ illnesses and injuries, as well as to depict the material and psychic lives of those subjected to intersecting forms of confinement and dispossession. I particularly work with migrants whose bodies tend to be “somatically othered”—such as Afro-Latinx, indigenous, and trans/queer migrants—as they routinely face some of the highest levels of violence on the migrant trail at the hands of state actors. I analyze the “humanitarian reason” that intervenes on these bodies (especially when they are “ill” or “injured”) and then track when certain somatic qualities or bodily traumas permit one to also acquire particular documents or state resources. Ultimately, I claim that the Southern Border Program does not simply seek to deport migrants, but to eliminate the bodily ability of migrating as such. Therefore, in The Body Migrant I ask the ontological question: Is one still a migrant if they are unable to migrate? Theoretically, I draw heavily upon the work of André Leroi-Gourhan in order to provide a novel materialist and structuralist conceptualization of what the human and the human body are, and therefore what the migrant body is as well. I make special use of Leroi-Gourhan’s conceptualization of “external organs”—that is, aspects of the human body which are externalized from it, such as what are colloquially referred to as “tools”—in order to analyze how one’s being is changed when they have access or are denied particular external organs. In doing so, I set out a different means of bodily analysis that departs from biomedical categories such as “biology” and “genetics,” and instead focus on the body as a corpus, that is, as a body of work and a body that works. I claim that immigration documents (such as passports or “humanitarian visas”) can actually be understood as physically part of one’s corpus, actually structuring the notion of one’s organic body and individualized identity to which it is attached.

Advisor: Holmes, Seth M
Multilingual Education for Sale: The Neoliberalization of Language Education Policy

Neoliberalism has become the hegemonic rationality of our time, framing nearly every aspect of our social world in terms of competition. This dissertation sheds light on neoliberal infiltration and naturalization within the field of language education through three distinct but interrelated papers. In Discourses of dual language bilingual education, I map out the discursive landscape of the field and, building on Ruiz (1984), I theorize a cross-epistemic model to demonstrate why the English-as-resource paradigm of the nationalist era has transformed into a multilingualism-as-resource paradigm within the current neoliberal era. In Rebranding bilingualism: The shifting discourses of language education policy in California’s 2016 election, I use critical discourse analysis to compare Proposition 227 (1998), which effectively banned bilingual education in California, with its legislative repeal, Proposition 58 (2016), specifically demonstrating the discursive shift to neoliberalism that occurred between 20th and 21st century language education policies. In Mechanisms of neoliberalization within California’s language education policy, I draw on the tools of critical discourse analysis as well as corpus linguistics to examine California language education policy texts spanning from 1967 to the present, laying bare three discursive mechanisms of neoliberalization within the field: 1) infiltration of market-based vocabulary; 2) terminological sloganization; and 3) commodification of multilingualism./nWhile the neoliberalization of language education has contributed to more widespread support of bilingual education—now rebranded as multilingualism—it has also altered the reasons behind this support—from promoting equity and social justice to a market-based rationale of expanding individual opportunity in an increasingly globalized world. My findings point to the ways in which those who have traditionally been served by bilingual education—that is, racially and linguistically minoritized students—are being crowded out by more privileged (i.e., white) students seeking a competitive edge in the global market era. Neoliberal policies–through color-blind, a-historic, and universalistic rhetoric–are deceptively designed to appear objective and democratic (“for all”). I argue, however, that neoliberalism undermines democracy by reproducing colonial relations of power that privilege Whiteness. This collected work contributes to a deeper understanding of the political work of language.

Advisor: Sterponi, Laura
Essays on Public and Labor Economics

This dissertation studies different policies that affect labor markets and inequality. The first chapter studies whether minimum wages should be used for redistribution on top of taxes and transfers. Theoretical results show that a minimum wage can increase social welfare when it increases the average post-tax wages of low-skill labor market participants and when corporate profit incidence is large. When chosen together with taxes, the minimum wage can help the government redistribute efficiently to low-skill workers by preventing firms from capturing low-wage income subsidies and from enjoying high profits that cannot be redistributed via corporate taxes due to capital mobility. Empirically, the analysis shows that the average US state-level minimum wage reform over the last two decades increased average post-tax wages of low-skilled labor market participants and reduced corporate profits in affected industries, namely low-skill labor-intensive services. The second chapter, written jointly with Maximiliano Lauletta, empirically studies a reform to the workers' compensation system in Argentina that, after a workplace accident, mandated workers to go through a government medical commission that determines the degree of disability, whether the injury happened in the workplace, and the corresponding compensation, before additional legal actions can be taken. Leveraging the staggered implementation of the reform across provinces, the results show that the reform substantially reduced workplace lawsuits with no effects on reported accidents. Employment increased by more than 5% one year after the reform in highly exposed industries, with no effects on average earnings or the number of active firms. Finally, the third chapter empirically asks if policies and institutions matter for pre-tax income inequality. Based on an annual panel of 43 countries for the period 1980–2016, the analysis documents robust correlations between pre-tax income shares and economic policy—financial development, trade openness, government expenditure, and income taxation—even after controlling for economic development. I further find that proxies of institutional quality—e.g., state development, corruption, or political exclusion—mediate the relationship between top income shares and economic policy, in particular for trade openness and government expenditure.

Advisor: Yagan, Danny
Pronouns and agreement in San Juan Atitán Mam

The focus of this dissertation is the San Juan Atitán (SJA) variety of Mam, a Mayan languagespoken in the highlands of Guatemala. This work brings together descriptive, theoretical, and revitalization threads research on this variety of Mam, which is a highly underrepresented variety in the literature on Mam. The dissertation contains a broad sketch of SJA Mam grammar as a whole, which contributes to the documentation and formal description of variation within the Mam language. The main empirical domain examined in this dissertation is that of pronouns and agreement. While object pronouns in Mayan languages are consistently realized on the verb via agreement, object pronouns in SJA Mam co-occur with default agreement on the verb and full pronouns in object position. This structure has consequences for syntactic theories of object licensing, the movement of objects over subjects, syntactic ergativity, and the realization of agreement morphology– in Mayan languages and beyond. Similarly unique in SJA Mam are subject and possessor pronouns: these pronouns are realized on the verb via agreement as well as reduced pronouns in argument position. The generalization emerges that pronouns undergo reduction only when they trigger agreement morphemes on the verb. The distribution of double marking of pronouns (agreement and pronouns) and the pattern of reduction suggests that morphological operations can be sensitive to whether individual morphosyntactic features have been Agreed with./nThis theoretical research has been carried out alongside collaborative work with members of theMam community, namely via Mam language and culture classes in which I was a co-instructor for over three years. In this dissertation, I discuss the history and impacts of the courses in addition to technologies and teaching strategies in order to inspire and provide examples for others engaged in revitalization work.

Advisor: Deal, Amy Rose
Jenks, Peter
Some aspects of geometric actions of hyperbolic and relatively hyperbolic groups

This thesis consists of two projects related to groups acting on metric spaces of non-positive curvature./nIn the first project, we show that relatively hyperbolic groups acting properly and cocompactly on $\mathrm{CAT}(0)$ cube complexes are virtually special, provided the peripheral subgroups are virtually special in a way that is compatible with the cubulation. This extends Agol's result for cubulated hyperbolic groups (which led to the proof of the Virtual Haken Conjecture), and applies to a wide range of peripheral subgroups. In particular, we deduce virtual specialness for properly and cocompactly cubulated groups that are hyperbolic relative to virtually abelian groups. As another consequence, by using a theorem of Martin and Steenbock we obtain virtual specialness for $C'(1/6)$-small cancellation quotients of free products of virtually special groups. For the proof of our main result, we prove a relative version of Wise's quasiconvex hierarchy theorem./nIn our second project, we study the metric and topological properties of the space $\mathscr{D}_{\Gamma}$ of metric structures on the non-elementary hyperbolic group $\Gamma$, which parametrizes geometric actions of $\Gamma$ on Gromov hyperbolic spaces. This space contains the Teichm\"uller space when $\Gamma$ is a surface group and the Culler-Vogtmann outer space when $\Gamma$ is a free group. Equipped with a natural metric reminiscent of Thurston's metric on Teichm\"uller space, we prove that $\mathscr{D}_{\Gamma}$ is unbounded, contractible and separable, and that $\mathrm{Out}(\Gamma)$ acts metrically properly by isometries on it. If we restrict to the subspace $\mathscr{D}^{\delta}_{\Gamma}$ of the points represented by actions on $\delta$-hyperbolic spaces with exponential growth rate 1, we prove that it is either empty or proper, and that the Bowen-Margulis map from $\mathscr{D}^{\delta}_{\Gamma}$ into the space $\mathbb{P}\mathcal{C}urr(\Gamma)$ of projective geodesic currents on $\Gamma$ is continuous. By finding an $\mathrm{Out}(\Gamma)$-invariant geodesic bicombing for $\mathscr{D}_{\Gamma}$ we also construct a boundary for this space, which parametrizes improper actions of $\Gamma$ on hyperbolic spaces. As a corollary of this construction, we deduce continuous extension of translation length functions to the space of geodesic currents, which we use to disprove a conjecture of Bonahon about small actions of hyperbolic groups on $\mathbb{R}$-trees.

Advisor: Agol, Ian