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Prevotella Phylogeny: Genomic And Molecular Insights Into The Role Of The Human Commensal Prevotella In Cystic Fibrosis
Get PDFThe genus Prevotella comprises of a diverse set of gram-negative anaerobes that are implicated in both health and disease. Prevotella is a common human commensal of various anatomic sites but can also be associated with the dysbiotic microbiomes of various chronic inflammatory diseases. Due to it’s association with both commensalism and disease, the role of Prevotella in disease progression is unclear. However, Prevotella has shown immunomodulatory potential, the ability to change the metabolic microenvironment and other cytotoxic phenotypes in both in vitro and in vivo studies. Despite this, Prevotella remains understudied both at the genomic and phenotypic levels. In this thesis, we explore the role of Prevotella in the context of the cystic fibrosis lung microbiome. In this thesis we characterize the ecological composition of a longitudinal pediatric CF cohort called EcoCF and show that the prevalence and relative abundance of Prevotella remains relatively stable from mild to severe lung disease. Prevotella is often the dominant species in samples of higher bacterial diversity, which is associated with higher lung function but is also differentially enriched in samples of lower lung function, where bacterial diversity is low. We attempt to explain this contradictory result by exploring the genomic diversity in the genus Prevotella, with a focus on P. melaninogenica and its closely related species that are often associated with the CF lung. We show that P. melaninogenica is a complex of species with varied potential for horizontal gene transfer. Prevotella species have high recombination rates but also complex restriction-modification systems. Our work highlights the incredible genomic diversity within some of the oropharyngeal commensal Prevotella, indicating that the key to drawing meaningful associations of Prevotella with health and disease is by studying the genus Prevotella resolved at the strain-level
Essays On Economic Growth And Inequality
Get PDFThis thesis studies the impact of policy changes and technological progress on economic growth and inequality.
The first chapter studies the impact of intellectual property rights protection policies on firms\u27 boundary and innovation choices, and economic growth. This chapter shows specialization patterns of US firms in the 1980s and 1990s. Specifically: 1) Firms, especially innovating ones, decreased the number of industries in which they produce. 2) Small firms increased innovation intensity while large firms decreased it. A new hypothesis is proposed, highlighting the role of pro-patent reforms that make firms\u27 innovations more tradable. An endogenous growth model with firm heterogeneity is developed. Calibrating the model suggests that increasing tradability of innovations can explain 25% of the decrease in firms’ number of industries and 58% of the reallocation of innovation activities. It results in a 0.64 percent point increase in the annual economic growth rate.
The second chapter explores how the rise of digital advertising technology affects consumption, leisure, and welfare of high- and low-income consumers. An information-theoretic model is constructed where free media goods complement leisure and are financed by two types of advertising that inform consumers about the prices of goods--traditional and digital. Calibrating the model shows that the increasing provision of free media goods, due to the rise in digital advertising, boosts consumer welfare significantly. It also leads to more leisure. The increase in leisure is more pronounced for low-income consumers vis-a-vis the high-income ones.
The third chapter studies the role of the venture capital (VC) industry in shaping wealth inequality and mobility in the United States. This chapter develops a model where households endogenously choose entrepreneurship entry and the source of external funds (bank or VC). The model can quantitatively match the wealth distribution in the United States. Calibrating the model generates that the VC sector: 1) increases the wealth share of the top 0.1% households by 1 percent points and the wealth share of the top 1% households by 2.1 percent points, 2) increases the probability that the households at the bottom 99% move to the top 1% after a generation by 1.4 percent points
Causal Inference Methods For Joint Censored Cost And Effectiveness Outcomes
Get PDFInformed healthcare policy decisions must be driven by consideration of an intervention\u27s effectiveness as well as its cost. Cost-effectiveness analyses provide a framework for decision making that balances these joint outcomes in some optimal way. However, because these studies often use data from observational sources, results may be biased due to unmeasured or time-varying confounding, informative cost censoring, and skewed or zero-inflated data. The goals of this dissertation are two-fold; we aim to (1) elucidate the conditions under which causal conclusions can be drawn from cost-effectiveness data, and (2) develop novel statistical methods for identifying cost-effective treatments while accounting for confounding and other data irregularities. We discuss three such developments: regression methodology for a novel probabilistic measure of cost-effectiveness, interpretable Q-learning based methods for identifying cost-effective treatment strategies, and a flexible and efficient influence function based estimator of average treatment cost that is robust to unmeasured confounding given a valid instrumental variable. We evaluate the operating characteristics of our proposed methods under several realistic data scenarios through simulation studies. We also illustrate usage by identifying cost-effective adjuvant treatments for early-stage endometrial cancer patients as well as assessing differences in costs between surgical and non-surgical interventions for gallstones and hemorrhaging using observational data
Essays On The Economics Of Disaster Risk
Get PDFThis dissertation explores disaster risk in the context of a changing climate, imperfect public policies, and frictions that limit the capitalization of current and future climate risk in housing markets. The chapters\u27 results suggest how better provision of information and policies that internalize homeowners\u27 and lenders\u27 climate exposure can ameliorate the costs of climate change in real estate markets.
In my first chapter, I study the economic consequences of using better flood risk models to more accurately identify and price flood insurance for high-risk homes. I estimate my results with administrative flood insurance policy data and a novel survey measuring flood insurance demand, risk perceptions, and objective risk. To identify the effects of risk information, I use variation created by outdated elevation data and risk models that caused high-risk homes to be misclassified as low-risk. My findings show that flood risk classification provides valuable information not only for insurers, but also for homeowners. Misclassifying high-risk homes as low-risk causes owners to underestimate their current and future flood risk, invest less in risk-reducing adaptation, and buy less flood insurance despite substantially lower premiums. Embedding these estimates in a sufficient statistics model with dynamic risk and endogenous risk beliefs and adaptation, I find that identifying and pricing the estimated six million high-risk homes outside the floodplain would increase social welfare by \$138 billion.
In the second chapter, co-authored with Professor Benjamin Keys, we explore dynamic changes in the capitalization of sea level rise (SLR) risk in housing and mortgage markets. Our results suggest a disconnect in coastal Florida real estate: From 2013-2016, home sales volumes in the most-SLR-exposed communities declined 20\% relative to less-SLR-exposed areas, even as their sale prices grew in lockstep. By 2019, however, relative prices in these at-risk markets finally declined 5\% from their peak. Over this period, home sellers accumulated an excess inventory of unsold properties as they maintained high list prices and transaction volumes declined. Lender behavior cannot reconcile these patterns, as both all-cash and mortgage-financed purchases similarly contracted, with little increase in loan denials or securitization. We propose a demand-side explanation for our findings where SLR risk has become more salient in the home price expectations of prospective buyers than sellers. The lead-lag relationship between transaction volumes and prices in SLR-exposed markets is consistent with dynamics at the peak of prior real estate bubbles.
In the third chapter, co-authored with Dr. Yanjun Liao, we study how home equity influences homeowners\u27 decisions to insure flood risk. We show that low home equity is an important driver of low flood insurance take-up. To isolate the causal effect of home equity on flood insurance demand, we exploit price changes over the housing boom and bust. Insurance take-up follows house price dynamics closely, with a home price elasticity around 0.3. Multiple mechanism tests show evidence consistent with a debt overhang channel, whereby uninsured households with low equity rely on mortgage default to manage their flood risk. As a result, households do not fully internalize their disaster risk
The Impact of the Covid-19 Pandemic on Small Business Restaurants in Center City, Philadelphia, PA
Get PDFThis paper will attempt to provide restaurant owners and legislators alike a look into what restaurants in Philadelphia did to stay alive during the pandemic. As we grow our understanding of which decisions were crucial for ensuring success, we will also begin to understand which decisions were detrimental, neutral, or negative for restaurants’ success. We will assess the outcome of these decisions by asking restaurants which decisions taken were most successful in helping their business stay afloat. Finally, better comprehension of the hurdles imposed on restaurants by the government should inform future policy decisions in a way which maximizes public safety while acknowledging that there is an optimal number of COVID-19 cases that cannot be avoided without ruining the economy
Beyond Statistical Fairness
Get PDFIn recent years, a great deal of fairness notions has been proposed. Yet, most of them take a reductionist approach by indirectly viewing fairness as equalizing some error statistic across pre-defined groups. This thesis aims to explore some ideas as to how to go beyond such statistical fairness frameworks.
First, we consider settings in which the right notion of fairness may not be captured by simple mathematical definitions but might be more complex and nuanced and thus require elicitation from individual or collective stakeholders. By asking stakeholders to make pairwise comparisons to learn which pair of individuals should be treated similarly, we show how to approximately learn the most accurate classifier or converge to such one subject to the elicited fairness constraints. We consider an offline setting where the pairwise comparisons must be made prior to training a model and an online setting where one can continually provide fairness feedback to the deployed model in each round. We also report preliminary findings of a behavioral study of our framework using human-subject fairness constraints elicited on the COMPAS criminal recidivism dataset.
Second, unlike most of the statistical fairness framework that promises fairness for pre-defined and often coarse groups, we provide fairness guarantees for finer subgroups, such as all possible intersections of the pre-defined groups, in the context of uncertainty estimation in both offline and online setting. Our framework gives uncertainty guarantees that are more locally sensible than the ones given by conformal prediction techniques; our uncertainty estimates are valid even when averaged over any subgroup, but uncertainty estimates in conformal predictions are usually only valid when averaged over the entire population
Narrating The Industrial City: Intellectuals And The Italian Economic Boom (1955-1965)
No full textFrom the mid-1950s to the mid-1960s, the Italian economy underwent a massive economic boom that propelled Italy from the labeling of a “backwards” agrarian nation to a competitor on the international market. Exports skyrocketed as millions flocked to the industrial city, leaving behind their roots—both the literal crops nurtured for generations, and the connections that built families and sustained and social bonds. My dissertation explores the visual and literary culture of the so-called “miracle” years – in particular, the ways in which this culture represented the workers’ experience and the newly industrialized (often anonymous) spaces – to reinterpret the role of artists and intellectuals in confronting contemporaneity. Through industrial novelists Italo Calvino, Luciano Bianciardi, Paolo Volponi, and Ottiero Ottieri, I investigate the diversity of perspectives and the convergence toward criticism of the industrial age found in literature of the late 1950s and early 1960s, cultural and literary periodicals, and Michelangelo Antonioni’s cinematic tetralogy of the early 1960s.I argue that the industrial space (cities, factories, workspaces) should be considered a focal point in studying literature of the economic boom and it is through this urban lens that literary protagonists understand their new lives. I expand the image of the economic boom by showing how preestablished dichotomies like the city/countryside, natural/mechanical, North/South, industry/agriculture, public/private, integration/alienation, and harmony/disharmony are more nuanced than their contradictions suggest. I also show how the industrial space provokes feelings of alienation and isolation not only in the working class, but in the intellectual as well, who also becomes a “worker” that must bend to the will of the system he claims to resent. In studying industrial literature and how intellectuals represented industrialized spaces in their texts, I delve into several other fields of inquiry, including environmental studies, urbanism, cultural studies, phenomenology, affect studies, and media studies. I begin through the wide lens of environmental theory and socio-spatial relationships and conclude on the interior of the petrochemical plant that looms over Antonioni’s Ravenna in Il deserto rosso (1964). My dissertation thus merges intellectual writers, their semi-autobiographical protagonists, and the expanding urban world to show how the culture of these years was shaped by the omnipresent, industrial space
The Specter Of Gendered Violence: Tracing The Intertwined Legacies Of Colonialism And Sexism In Puerto Rican Literature
No full textIn Puerto Rico, the issue of gendered violence has been bubbling under the surface for decades from a centuries-old paternalist culture. Examining culture through literature, my dissertation illuminates the entangled connection between colonialism and gendered violence as my analysis traces in literary texts from the late nineteenth century to the 1970s and early 1980s a collective sense of disillusion, defeat, and demoralization that stems from Puerto Rico’s perpetual colonialism and establishes what I call a foundational pessimism. I argue that colonial and gendered violence are inextricably linked and manifest as a web of pain where it is impossible to closely examine one without confronting the other. Furthermore, I suggest that these forms of violence leave wounds that are inherited through generations provoking a haunting effect within families and society at large. Starting in the first chapter with a reading of La charca (1894) by Manuel Zeno Gandía in light of Anne McClintock’s notion of the gendered nation and following up with two of René Marqués’s plays, La carreta (1953) and Los soles truncos (1958), I demonstrate the various reactions to colonialism that led to a paternalist nation that dismisses women. In my readings of these texts, all penned by men, I argue, moreover that Gandía’s canonical national novel set the stage for subsequent canonical literature in the early twentieth century to perpetuate harmful and sexist stereotypes about women. In the following two chapters, my analysis pivots to feminist fiction by women writers that brings these issues to light. In my reading of Rosario Ferré’s “Amalia” and “La muñeca menor,” both published in Papeles de Pandora (1976), as well as Ana Lydia Vega’s “Pasión de historia” (1982) I examine how women suffer the consequences of colonization through often-silenced violence. My analysis of their corpus shows how they push back against the literary old guard by denouncing gendered violence, condemning victim blaming, and encouraging female creation. As a whole, my dissertation aims to shed light on an often-silenced issue: the culture of misogyny embedded in Puerto Rico’s canonical literature and how it bleeds into gendered violence
Cosmology Via The Sunyaev-Zeldovich Effect
Get PDFThe study of clusters of galaxies is one of the most exciting and fruitful sub-fields of astronomy today; their number and distribution serve as powerful probes of the underlying cosmology, while their inner workings and structure are laboratories for astrophysics. In the Sunyaev-Zeldovich (SZ) effect photons from the Cosmic Microwave Background (CMB) inverse Compton scatter off of hot electrons in the intracluster media (ICM). The SZ effect directly probes the pressure of the ICM and is nearly redshift independent, and hence is a powerful tool for both detecting clusters and investigating their structure. Currently, CMB survey instruments are creating large, mass limited catalogs of galaxy clusters out to redshifts of , and in the near future next generation CMB experiments will push these catalogs out to nearly a redshift of . Simultaneously, high resolution sub-millimeter experiments are mapping the structure of clusters, giving us insight into the astrophysics that govern these clusters and their interface to cosmology. In this thesis I detail work done in the design, integration, and testing of the Large Aperture Telescope Receiver (LATR) for the next generation CMB experiment, Simons Observatory (SO). The LATR will create field leading cluster catalogs, allowing us to test cosmology out to a redshift of . In particular this work will focus on simulations performed in the service of the LATR design process, as well as thermal validation tests that were done to validate the performance of the LATR. In addition, I report on the calibration of the mass-richness scaling relation for the Massive and Distant Clusters of Wise (MaDCoWS) cluster catalog using the current generation Atacama Cosmology Telescope (ACT). Finally, I report on the measurement by the MUSTANG-2 instrument of the thermodynamic state of a pair of x-ray cavities in the cluster MS 0735.6+7421 which were formed by the action of an active galactic nucleus. The mechanism of support for these cavities is not well understood, and the measurements we make of their thermodynamic state help to shed light on this topic
The Hard-To-Measure Aspects Of Firms
Get PDFThis dissertation explores the aspects of firms that are hard-to-measure, hard-to-observe, and hard-to-quantify.
Chapter 3 investigates amenities of work that go beyond a wage. Using matched employee-employer data for the United States, this chapter estimates the joint distribution of wages, amenities, and job satisfaction across firms. There are three main findings. First, high-paying firms are high-satisfaction firms because they offer better amenities. Second, workers, especially high-earners, are willing to pay for job satisfaction, gaining in amenity value at least 50 percent of the average wage when moving from the worst- to the best-amenity firms. Third, since the elasticity of total compensation inclusive of amenity value to wages across firms exceeds one, incorporating non-wage amenities raises total compensation variance across firms by at least 52 percent.
Chapter 4 investigates firm reputation. Using workers\u27 volunteered reviews on the platform Glassdoor, we find that the content most valuable to jobseekers (negative information) is the kind most risky to supply, pointing to a Catch-22. Higher ratings increase labor supply to less well-known firms, creating an incentive for smaller firms to discourage negative reviews. Concerns about employer retaliation discourage negative reviews and motivate employees who do disclose to conceal aspects of their identity, degrading the information’s value. Reputation institutions provide valuable but partial solutions to workers\u27 information problems.
Chapter 5 investigates firm culture. Using a sample of corporate scandals and data from the website Glassdoor, we study how negative reputation shocks affect the relationship between firms and their employees. Worker sentiment declines sharply and persistently following scandals, driven by diminished perceptions of management and culture. While base earnings and fringe benefits remain unchanged, variable compensation falls 10 percent. Our results demonstrate that rank-and-file employees are adversely impacted by corporate misconduct