This dissertation consists of three essays in the field of environmental economics. The first chapter provides the first causal evidence that hostile activities online lead to physical violence. Given the recently documented relationship between pollution and social media, I exploit exogenous variation in local air quality as the first step to instrument for online aggression. In an event study setting, I find volatile organic compounds (VOCs) increase by 7% when refineries experience unexpected production outages. Together with higher air pollution, I find more aggressive behaviors both online and offline, as well as worse health outcomes near refineries. A one standard deviation increase in surrounding VOCs leads to 0.16 more hate crimes against Black people and 0.23 more hospital visits per thousand people each day. Second, I consider how emotional contagion spreads through social networks. On days with pollution spikes, surrounding areas see 30% more offensive and racist tweets and 12% more crimes; those geographically distant but socially networked regions also see offensive and racist tweets increase by 3% and more crimes by 4.5%. Nationally, overlooking spillovers would underestimate crime effects of pollution by 24%. My findings highlight the consequences of social media hostility and contribute to the public debate on cyberspace regulation. The second chapter, which is coauthored with Andrew Wilson, analyzes the relationship between weather and railway accidents. Rail thermal expansion and contraction are key considerations in rail design and construction; rail operators and rolling stock may likewise exhibit vulnerability to temperature changes. We quantify the sizes of these effects by leveraging a comprehensive dataset of railway malfunctions in the United States spanning 1997-2019. We find that both heat and cold cause elevated rates of railway malfunctions, with relatively larger increases in the number of incidents leading to a casualty as well as the number of injuries and deaths resulting from these incidents. We find that exposure to daily temperatures averaging over 30°C (86°F) leads to a 16% increase in the number of rail malfunctions, a 13% increase in the number of incidents leading to a casualty, and 18% and 36% increases injuries and deaths-effects net of any operational adjustments made to mitigate these effects. Further, while we also find that warmer locations exhibit a weaker relationship between heat and railway malfunctions, we find no evidence that companies are learning, year-over-year, how to reduce accidents. Finally, we note that effects of heat are strongest for derailments (versus other types of malfunctions) and freight trains (versus passenger trains). Our findings highlight the vulnerability of the railway system to the climate. The number of injuries and deaths associated with weather exposure-especially in comparison to operators' reported private costs of equipment failure-suggests a role for enhanced rail safety regulations and adaptation funding to protect critical heat-exposed infrastructure. The third chapter, which is a joint work with Douglas Almond and Muye Ru, explores the impact of federal policy rollback on methane leakage. Improvements in satellite measurement enable independent assessment of regulatory and climate policy. In August 2020, the Trump Administration lifted Obama-era requirements that oil and gas firms detect and repair methane leaks. We merge geo-identified data from the European TROPOMI (satellite instrument) to the specific locations of the US oil and gas infrastructure. Using a difference-in-differences design, we find a prompt increase in US methane emissions following the summer 2020 rollback. The number of high-methane emission events from the oil and gas sector more than doubled after the rollback relative to the coal sector, which did not experience the same regulatory rollback. While the oil and gas industry claims it faces a persistent, profit-making incentive to stem natural gas leaks and emissions, we find a large and nimble response by industry to changes in federal policy. Public policies that reduce methane externalities are critical given that global methane concentrations are rising at an increasing rate.

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[pt] Este trabalho trata do problema real de avaliar a capacidade de processamento de pátios ferroviários planos de classificação. Nesses pátios, os vagões são recebidos em trens e movimentam respeitando a disposição dos trilhos e a formação sequencial do trem de saída. Movimentações ineficientes implicam em uma capacidade de processamento inferior à potencial do pátio dado seu layout. O objetivo desta pesquisa é descrever o problema e incitar um método capaz de calcular a capacidade de processamento de pátios ferroviários planos de classificação no horizonte estratégico, indicando se existe ou não a necessidade de um projeto de expansão para garantir atendimento à demanda prevista. O problema foi modelado através de programação linear inteira mista (MILP) baseado na teoria de sequenciamento de produção. O modelo foi aplicado em instâncias de teste, reproduzindo movimentações reais de vagões, e provou avaliar diferentes layouts adequadamente, porém com elevado tempo de execução. A inicialização de algumas variáveis binárias do modelo permitiu um incremento de tamanho nas instâncias, porém ainda inviável para aplicação na prática. / [en] This work deals with the real problem of evaluating the processing capacity of flat rail classification yards. In these yards, the railway cars are received on trains and move respecting the car sequence of the outgoing train. Inefficient movements imply a lower processing capacity than the yard s potential given its layout. The objective of this research is to describe the problem and to incite a method capable of calculating the processing capacity of flat rail classification yards in the strategic horizon, indicating whether or not there is a need for an expansion project to ensure meeting the expected demand. The problem was modeled using mixed integer linear programming (MILP) based on production scheduling theory. The model was applied to test instances, reproducing real railway car movements, and proved to evaluate different layouts properly, but with a high execution time. The initialization of some binary variables of the model allowed an increase in the size of the instances, however it is still unfeasible for practical application.

<p>This dissertation identifies four American novels published between 2016 and 2018—Colson Whitehead’s <em>The Underground Railroad</em> (2016), Jesmyn Ward’s <em>Sing, Unburied, Sing</em> (2017), Celeste Ng’s <em>Little Fires Everywhere</em> (2017), and Tommy Orange’s <em>There There</em> (2018)—that deploy a multifocal narrative structure to facilitate readers’ ethical engagement with their content. Specifically, these novels’ narrative structures guide readers through spatial reading, or reading across numerous characters’ perspectives of a shared space instead of with the grain of chronological time. Contextualizing these novels within the nation’s shifting racial beliefs initiated by the election of Barack Obama in 2008 and the election of Donald Trump in 2016, I argue that, in these novels, multifocalization and the spatial reading it activates dismantle the cognitive schemas and cultural discourses that sustain unjust racial ideologies. Spatial reading engages readers in acts of rereading and contextualization that diverge from the practices of generalization and erasure affiliated with myths of racial progress and the rhetoric of colorblindness, and it accordingly builds readers’ capacity to acknowledge racism as systemic, structural, and multifaceted. By emphasizing how each novel facilitates readers’ racial literacy, this project diverges from and complicates the widespread belief that the humanities contribute to antiracism by building readerly empathy, instead championing how the humanities impart upon readers the tools to analyze and critique systemic racism. </p>

Järnvägen transporterar människor samt gods billigt och miljövänligt. I Sverige identifierar Trafikverket flera alternativa sträckningar när de planerar en ny järnväg. Landskapets karaktär, miljöförhållanden, geologi, tätortsstruktur, befolkningsutveckling, resande och transporter är exempel på kriterier som kan påverka beslutet om var dessa sträckningar ska placeras. Geografiska Informationssystem (GIS) kan standardisera processen för att identifiera flera möjliga korridorer. Syftet med detta examensarbete är att ge rekommendationer på hur GIS, särskilt cost path och känslighetsanalys, kan användas vid planering av nya järnvägskorridorer. Ett testfall i Blekinge län valdes för att illustrera potentialen i dessa metoder. Examensarbetet utvärderar även den nuvarande användningen av GIS inom företagsvärlden genom semistrukturerade intervjuer med medarbetare på Vectura Consulting AB. Cost path och känslighetsanalysen identifierar fem olika korridorer där olika teman (miljö, jordarter, markanvändning, lutning och lika vikt) används och viktas enligt deras betydelse. De resulterande sträckningarna, speciellt sträckningen som baserades på markanvändningstemat, överensstämmer till viss del en planerad korridor från en tidigare förstudie. Intervjuerna indikerade att GIS ses som ett användbart verktyg men att det idag används huvudsakligen för presentation och visualisering av data. Resultaten visar att det finns en önskan om att använda GIS för att utföra analyser. Det kan även användas som ett samgranskningsverktyg för att lätt visualisera alla parters intressen. En nackdel däremot, är att det tar tid att lära sig och förstå samt att det krävs kunskap för att behärska det fullt ut. Trots skillnaderna i hur den planerade korridoren och de GIS-genererade korridorerna skapades, visade resultatet likheter mellan dem. De övergripande resultaten indikerar att GIS, speciellt cost path-analyser är ett användbart verktyg för att välja nya järnvägs korridorer. / Railway systems transport people and goods in an economic and environmentally-friendly way. In Sweden the Transport Administration identifies several possible routes when planning a new railway. Landscape features, environmental conditions, geology, population structure, population trends, travel and transport are examples of criteria that can affect decisions about the location of the routes. Geographical Information Systems (GIS) can standardize the process of identifying several possible corridors. The main aims of this thesis are to recommend on how GIS and particularly cost path and sensitivity analysis can be used to plan new railway tracks. A test case in Blekinge County (southeastern Sweden) was selected to illustrate the potential of these methods. The thesis also assesses the current use of GIS in the industry through semi-structured interviews of employees of Vectura consulting AB. The cost path and sensitivity analyses identified five different corridors. Different selection themes (environment, soil, land-use, slope and equal weight) were used and weighted, according to their importance. The selected routes especially the land-use theme correspond in a part to a corridor identified by a previous study. The interviews indicated that GIS is seen to be a useful tool but that its use at present is primarily for presenting and visualizing data. The results suggest however that there is also a desire to use GIS to perform analyses. It can also be used as an assessment tool to easily visualize the interests of all parties. High training requirements were identified as the principal disadvantages of GIS based analyses. Despite differences in how the planned and the GIS-generated corridors were created, the results of the two methods were similar. Overall, the results indicate that GIS, particularly cost path-analysis can be a useful tool for selecting new railway corridors.

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Inom svenska järnvägen skapas en stor mängd information om hur objekt så som växlar och spårledningar beter sig, i form av dataloggar. Dessa används i dagsläget mycket sparsamt, trots sin stora potential till analys. Detta arbete ämnar utforma mjukvara som kan förädla dessa loggar och extrahera användbar information om banobjektens nuvarande och framtida tillstånd. Detta kan höja säkerheten och förebygga fel och på så vis minimera oplanerade driftstopp och kostsamma byten eller nödreparationer av utrustning. Arbetet resulterade i en mjukvara framtagen i Python som läser in loggar av godtycklig storlek och detekterar atypiska beteenden i ett flertal kategorier av banobjekt. Mjukvaran fungerar även som ett verktyg för mer användarvänlig hantering av dessa loggar, varur användaren kan sammanställa och presentera information som annars vore svårtillgänglig. / In the Swedish rail network, a large amount of information is generated regarding the behaviours of various objects such as switches and track circuits, which is then stored in logs. Currently, these logs are severely underused despite their great potential for analysis. The purpose of this project is to develop a software which can refine these logs and extract useful information about the current and future states of the objects. This can increase operational safety and prevent faults from occurring, thereby minimizing unplanned downtime and costly replacements or reparations of equipment. The project results in a software developed in Python which reads logs of an arbitrary size and detects atypical behaviours in several different categories of objects. The software also acts as a tool for more user-friendly handling of these logs, offering the ability to compile and present information which would otherwise be difficult to access.