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Essays in Public Policy
No full textThis dissertation consists of two essays in labor economics and political economy, both focused on Chile. The first examines the effect of changes in the level of collective bargaining on compensation, while the second explores the political effects of forced displacement. The first chapter studies the effect of allowing workers to expand bargaining units across firms on their wages. It focuses on a labor reform in Chile that prevented businesses from splitting their labor force into smaller legal entities, enabling workers to form larger collective bargaining units. This chapter uses a dynamic difference-in-differences design, comparing affected firms with firms in the same industries that were not impacted by the reform. The results show that the policy increased both the average earnings and the dispersion of earnings among full-time workers, without affecting employment levels or firms’ profitability. The effects are driven by businesses that initially employed fewer workers and in which firms shared a headquarters municipality, suggesting a key role of coordination costs. This evidence suggests that increasing the level of collective bargaining strengthens the bargaining power of full-time workers and may improve their welfare. The second chapter examines the long-term impact of forced relocation to disadvantaged neighborhoods on political participation, using evidence from a large-scale slum clearance program in Santiago, Chile, between 1979 and 1985. Under this policy, public housing was allocated to slum dwellers, with one-third remaining in their original neighborhoods and the rest relocated to peripheral, low-opportunity areas. Using rich archival and administrative data, we analyze the effects of displacement separately for adults and children. We find that displaced children and adults experienced a significant decline in voter registration in 2011, compared to non-displaced individuals. While the results show no overall effect on the likelihood of being a candidate, displaced adult males were significantly less likely to run for office. The impact of displacement on registration was weaker for individuals facing greater expected disruption, such as those relocated separately from their original slum community or who moved longer distances. These results are not driven by access to registration boards or criminal justice involvement. These findings suggest that forced displacement can have persistent intergenerational effects on political participation, with implications for the political representation of low-income communities
Estimation Using Second-Order Methods
Full text linkSecond-order methods are often more robust and efficient than first-order methods, particularly in scenarios where the eigenvalues of the Hessian matrix vary significantly in magnitude. However, computing and storing the Hessian, as well as solving the associated Newton systems, poses significant computational and memory challenges. This dissertation addresses this bottleneck under two parameter estimation problems: sparse Discrete Fourier Transform (DFT) recovery from incomplete signals and online statistical inference based on Newton methods. In Chapter 2, we propose a method to recover the sparse DFT of a signal that is both noisy and potentially incomplete, with missing values. The problem is formulated as a penalized least-squares minimization based on the inverse discrete Fourier transform (IDFT) with an L1-penalty term, reformulated to be solvable using a primal-dual interior point method (IPM). Although Krylov methods are not typically used to solve Karush-Kuhn-Tucker (KKT) systems arising in IPMs due to their ill-conditioning, we employ a tailored preconditioner and establish new asymptotic bounds on the condition number of preconditioned KKT matrices. Thanks to this dedicated preconditioner — and the fact that FFT and IFFT operate as linear operators without requiring explicit matrix materialization — KKT systems can be solved efficiently at large scales in a matrix-free manner. Numerical results from a Julia implementation leveraging GPU-accelerated interior point methods, Krylov methods, and FFT toolkits demonstrate the scalability of our approach on problems with hundreds of millions of variables, inclusive of real data obtained from the diffuse scattering from a slightly disordered Molybdenum Vanadium Dioxide crystal. Given the ubiquity of streaming data, online algorithms have been widely used for parameter estimation. In Chapter 3, we study an online sketched Newton method that leverages a randomized sketching technique to perform an approximate Newton step in each iteration, thereby eliminating the computational bottleneck of second-order methods. While existing studies have established the asymptotic normality of sketched Newton methods, a consistent estimator of the limiting covariance matrix remains an open problem. We propose a fully online covariance matrix estimator that is constructed entirely from the Newton iterates and requires no matrix factorization. Compared to covariance estimators for first-order online methods, our estimator for second-order methods is batch-free. We establish the consistency and convergence rate of our estimator, and coupled with asymptotic normality results, we can then perform online statistical inference for the model parameters based on sketched Newton methods. We also discuss the extension of our estimator to constrained problems, and demonstrate its superior performance on regression problems as well as benchmark problems in the CUTEst set
Translocon Dynamics During Protein Synthesis at the ER
No full textCells are enclosed by a membrane bilayer comprised of lipids and proteins. These membranes function to separate the extracellular environment from the internal cellular processes. Membrane proteins perform a wide variety of functions in the human cell. Most membrane proteins are synthesized at the endoplasmic reticulum (ER) membrane, where their transmembrane domains (TMDs) are inserted into the bilayer for subsequent folding and assembly. The GEL, PAT and BOS complexes have recently been defined as components of the “multipass translocon” (MPT) that coordinate with Sec61 to facilitate biogenesis of most metazoan multipass membrane proteins at the ER. In many cases, these multipass proteins also require the OST complex during synthesis, but how this is coordinated has only been explored for a small number of proteins. Here we present bioinformatic and biochemical analysis of the recruitment of both complexes to reveal how their access to the translocon is coordinated during protein synthesis. We utilize ultra-low input selective ribosome profiling to identify the co-translational clients of the MPT and OST. We find that the MPT subunits enrich for the same transcripts, and their recruitment is coordinated. The MPT is recruited during insertion of multiple TMDs. Some transcripts enriched by the MPT are also enriched by OST. Analysis of these footprints suggest that the MPT and OST respond to the opening and closing of the Sec61 channel, as dictated by the biophysical and topological requirements of the nascent chain. Overall, this work highlights the dynamic nature of the translocon during membrane protein biogenesis
Dynamic Hemispheric Asymmetry in the Hippocampus Throughout Memory Formation and Retrieval
Full text linkThe hippocampus is critical for forming and stabilizing spatial memories. Within the classic trisynaptic circuit inside the hippocampus, CA1 is the output region of the hippocampus and place cells in CA1 are considered to collectively support spatial representations. While the contribution of unilateral or bilateral CA3 inputs to CA1 (Schaffer collateral pathway) have been well characterized, less is known about how inputs from the left and right CA3 differentially shape spatial representation in CA1. Most models of hippocampal function treat CA3 as a unified region and overlook the possibility of hemispheric specialization within its projections. Recent work has pointed to lateralized features of hippocampal circuitry primarily at the molecular and behavioral levels, yet the functional relevance of this hemispheric asymmetry among place cells in vivo remains poorly understood. In this dissertation, I examine how left and right CA3 projections differentially contribute to the development and stabilization of spatial representations in right CA1 (CA1R) during learning. Using two-photon calcium imaging and optogenetic inhibition in head-fixed mice navigating a virtual environment, I characterize how CA1R spatial maps evolve over experience and how CA3 inputs support this process across distinct phases of learning. I find that CA1R maps emerge upon immediate novel exposure but are initially inaccurate. Over repeated laps, spatial maps gradually improve and stabilize after ~10 laps (early-phase), with later laps marking stability (late-phase). In the early phase, both CA3 inputs contribute to place field formation, but right CA3 inputs predominantly drive high-amplitude, reliable fields that support the development of accurate spatial representations. In the late phase, left CA3 inputs become more prominent, supporting the maintenance of stable and reliable fields. Complementary recordings of CA3 axonal activity within CA1R further reveal this dynamic hemispheric shift. Right CA3 axons exhibit elevated activity during the early phase, consistent with a role in supporting novel experience encoding. As learning continues and the environment becomes familiar, left CA3 axons show increased activity, aligning with their involvement in maintaining stable representations. These findings reveal a dynamic, experience-dependent shift in hemispheric contributions to spatial coding in CA1, moving from right-dominant during early learning to left-dominant during later stabilization. Taken together, these results suggest that CA3 inputs are functionally lateralized and that their roles in spatial representation evolve across phases of learning. In Chapter 1, I introduce the motivation for this work and review prior literature on hippocampal lateralization and familiarization in novel environments. In Chapter 2, I describe the computational methods I developed to detect and functionally analyze the activity of CA3 inputs with axonal resolution. In Chapter 3, I present evidence for hemispheric differences in the dynamics and influence of CA3 projections on CA1 spatial representations and how these differences switch between learning and post-learning phases of experiences. This work provides new insight into how dynamic lateralized hippocampal inputs support the evolution of spatial representations and lays the foundation for future work on experience-dependent memory processing
Constructing the Resistance Nation: Understanding Hezbollah‘s Identity, Sacrifice, and Legitimacy
No full textThis paper explores how Hezbollah in Lebanon constructs its identity, narrative of sacrifice, and political legitimacy through political theory and digital media. By starting from Nationalism and Pan-Arabism, the first chapter analyzes how Hezbollah responds to the historical marginalization of Shia, using the language of "resistance" to establish an identity framework and combines critical theory to reveal the dual role of its discourse in mobilization and control. The second chapter focuses on Hezbollah's official website Moqawama.org, using media and symbolic analysis methods to analyze how it constructs a "resistance culture" through "martyr" narratives, images, and religious language to strengthen its legitimacy in Lebanon and the region. The paper points out that Hezbollah's legitimacy does not come from the state system, but it is obtained through continuous narrative shaping and symbolic practice. Against the consequences of weak state governance and ongoing regional conflicts, its model provides a new perspective for understanding political mobilization and ideological reshaping in the contemporary Arab World
Waters of Unification: The Yuan Grand Canal as an Engine of Imperial Administration
Full text linkWhen the Mongols established the Yuan Dynasty in 1271, they inherited not only the vast territory of a fragmented China but also the structural challenge of ruling it. Their decision to build a northern capital at Dadu, far from the agrarian and economic heartlands of the south, raised an urgent logistical question: how could a steppe-based empire sustain power across such a spatial and cultural divide? This study explores how the Grand Canal, redesigned and extended under Yuan rule, became a crucial infrastructure that supported imperial governance. It focuses the canal’s role in facilitating long-distance movement of both essential goods and high-value commodities and uses porcelain as a proxy to investigate how the canal supported imperial logistics, cultural exchange, and regional integration. Through GIS modeling and archaeological evidence, the project evaluates how the redesigned canal improved transport efficiency and reshaped economic connections across the Yuan Empire
Narrating Chicago Chinatown: Language, Power, and Urban Belonging
No full textThis thesis investigates how the bilingual linguistic landscape (LL) of Chicago’s Chinatown constructs Chinese American identity and reflects broader structures of marginalization and power. Through qualitative content analysis of 274 signs, the study reveals how language in public space enacts symbolic boundaries, consolidates community identity, and mediates access and visibility. Signage related to public services and cultural heritage fosters intra-community cohesion, while bilingual signs produced by businesses and government entities often reinforce linguistic hierarchies and racialized surveillance. Drawing on David Harvey’s dialectical approach to urbanization, the thesis argues that Chinatown is both shaped by and shaping processes of exclusion, resistance, and identity formation. The LL emerges as a site of ideological struggle where space, language, and power intersect
The Sporadic Fluvial Regime of Pliva Vallis, the Outlet Valley of Jezero Crater Lake, Mars
Full text linkIn situ and orbital observations have suggested that Jezero crater (field site for the Mars 2020 Perseverance rover) once hosted a paleolake fed by two inlet valleys. An outlet valley, Pliva Vallis, is present on the eastern rim of the crater and raises the question of whether the lake system operated as an open basin or as a closed basin system with one or more overflow events. To tackle this uncertainty, we present a detailed morphological study of Pliva Vallis, using digital elevation models and imagery. The atypical morphology of the valley, including reincised fluvial layered deposits, a perched valley, and bedrock incision terraces, led us to interpret that Pliva Vallis was formed by discontinuous and episodic flows rather than from a steady outlet river. These observations allowed us to infer at least four main breach episodes and propose a new scenario for the evolution of the lake system over time. We give a minimum estimate of the duration of these overflow events using a 0-D model, simulating a valley formation by breach erosion and lake overflow. Modeling results suggest that each flood event causing a part of the incision of the outlet valley would not have lasted for more than a few weeks, and some may have lasted only a few days. These time scales are consistent with our morphological interpretation that the outlet valley was carved by discontinuous and temporary flows. In this scenario, Jezero lake was predominantly a closed basin, spilling over episodically in at least four breach events
Strike, Occupy, Resist: Tactics, Countergovernance, & Popular Sovereignty in Prison Rebellions
No full textPrison rebellions are instances of resistance which make visible and articulate the systemic injustices of the carceral system. This work directs focus towards the tactical repertoires found in the cases of the 1971 Attica Uprising, 1974 August Rebellion, and 2011 & 2013 Pelican Bay Hunger Strikes. In doing so, I seek to answer questions of how different tactics and framings mobilized by incarcerated people reflect alternative claims to citizenship, how different tactical repertoires inform alternative conceptions of popular sovereignty, and what alternative types of popular sovereignty can be identified. By conducting content analysis of archival materials regarding these cases, I find that these cases share the attribute of incarcerated individuals engaging in reframing themselves through alternative claims to citizenship grounded in traditional legal frameworks as well as radical, revolutionary ideologies. Such reframing reflects incarcerated people’s reconstructions of notions of citizenship, power, and collectivity. I mobilize the concept of “countergovernance” in order to capture how the tactics used by incarcerated individuals amount to three distinct alternative, provisional forms of popular sovereignty: popular sovereignty as an inversion of the carceral hierarchy of authority through the use of violence, popular sovereignty as an organized communal ethic of care, and popular sovereignty as a decentralized, embodied practice. This research reveals potential alternative ways prison resistance can be theorized to challenge prevailing notions of citizenship, governance, and power
Portuguese Liberal Imperialism: A Study in its Rise, Character, and Practice (1820-1910)
Full text linkThis thesis argues that the economic dependency of the Second Portuguese empire on its colonies through the 18th century was a fundamental factor in the construction of a unique Portuguese variety of liberal imperialism which consolidated illiberal colonial expansion and domestic liberal practices as coexisting national ideas. Portuguese liberals following the Civil War failed to extend their vision of extending equal political and judicial representation to their colonial subjects, choosing instead to impose vehemently illiberal practices that served to maintain a decadent colonial empire through force and might as opposed to equality. The thesis traces the dual necessity of Portuguese statesmen to simultaneously reform an illiberal ultramarine empire and to sustain a weak, underdeveloped Portuguese economy dependent on colonial exploitation. This thesis ultimately seeks to deliver an argument that forces scholars of liberalism and empire to reconsider their focus on the British, Dutch, and French, and compel them to widen their case study window to include Portugal and its unique liberal imperial processes