231 research outputs found

    Home Front as Warfront: African American World War I Drama

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    This dissertation recovers little-known African American World War I plays that blur the boundary between the home front and warfront. I argue that with this focus, the plays wage their own war for African American citizenship rights, using language and performance to gain access to the "imagined" community of the nation. Yet plays from different time periods focus on diverse aspects of the Great War; these differences provide insight into how World War I was thought of and employed, and for what purposes, in African American communities during the interwar years. The project fills an important gap in African American drama, theatre, and war literature scholarship; no book-length analysis exists, yet scholarly conversations surrounding African Americans in the Great War are energetic. Despite scholars' arguments that the war "gave birth" to the New Negro, the plays that dramatize the subject have drifted into obscurity. Thus, this project is overdue; the plays complete the historical picture of African American drama and provide a better understanding of the ways contemporary life in the United States is still haunted by World War I

    The World Gas Model: A Multi-Period Mixed Complementarity Model for the Global Natural Gas Market

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    We provide the description and illustrative results of the World Gas Model, a multi-period complementarity model for the global natural gas market. Market players include producers, traders, pipeline and storage operators, LNG liquefiers and regasifiers as well as marketers. The model data set contains more than 80 countries and regions and covers 98% of world wide natural gas production and consumption. We also include a detailed representation of cross-border natural gas pipelines and constraints imposed by long-term contracts in the LNG market. The Base Case results of our numerical simulations show that the rush for LNG observed in the past years will not be sustained throughout 2030 and that Europe will continue to rely on pipeline gas for a large share of its imports and consumption.

    Multi-Period Natural Gas Market Modeling - Applications, Stochastic Extensions and Solution Approaches

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    This dissertation develops deterministic and stochastic multi-period mixed complementarity problems (MCP) for the global natural gas market, as well as solution approaches for large-scale stochastic MCP. The deterministic model is unique in the combination of the level of detail of the actors in the natural gas markets and the transport options, the detailed regional and global coverage, the multi-period approach with endogenous capacity expansions for transportation and storage infrastructure, the seasonal variation in demand and the representation of market power according to Nash-Cournot theory. The model is applied to several scenarios for the natural gas market that cover the formation of a cartel by the members of the Gas Exporting Countries Forum, a low availability of unconventional gas in the United States, and cost reductions in long-distance gas transportation. The results provide insights in how different regions are affected by various developments, in terms of production, consumption, traded volumes, prices and profits of market participants. The stochastic MCP is developed and applied to a global natural gas market problem with four scenarios for a time horizon until 2050 with nineteen regions and containing 78,768 variables. The scenarios vary in the possibility of a gas market cartel formation and varying depletion rates of gas reserves in the major gas importing regions. Outcomes for hedging decisions of market participants show some significant shifts in the timing and location of infrastructure investments, thereby affecting local market situations. A first application of Benders decomposition (BD) is presented to solve a large-scale stochastic MCP for the global gas market with many hundreds of first-stage capacity expansion variables and market players exerting various levels of market power. The largest problem solved successfully using BD contained 47,373 variables of which 763 first-stage variables, however using BD did not result in shorter solution times relative to solving the extensive-forms. Larger problems, up to 117,481 variables, were solved in extensive-form, but not when applying BD due to numerical issues. It is discussed how BD could significantly reduce the solution time of large-scale stochastic models, but various challenges remain and more research is needed to assess the potential of Benders decomposition for solving large-scale stochastic MCP

    A Complementarity Model for the European Natural Gas Market

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    In this paper, we present a detailed and comprehensive complementarity model for computing market equilibrium values in the European natural gas system. Market players include producers and their marketing arms which we call "transmitters", pipeline and storage operators, marketers, LNG liquefiers, regasifiers, tankers, and three end-use consumption sectors. The economic behavior of producers, transmitters, pipeline and storage operators, liquefiers and regasifiers is modeled via optimization problems whose Karush-Kuhn-Tucker (KKT) optimality conditions in combination with market-clearing conditions form the complementarity system. The LNG tankers, marketers and consumption sectors are modeled implicitly via appropriate cost functions, aggregate demand curves, and ex-post calculations, respectively. The model is run on several case studies that highlight its capabilities, including a simulation of a disruption of Russian supplies via Ukraine.European natural gas market, global LNG market, mixed complementarity problem

    Representing GASPEC with the World Gas Model

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    This paper presents results of simulating a more collusive behavior of a group of natural gas producing and exporting countries, sometimes called GASPEC. We use the World Gas Model, a dynamic, strategic representation of world gas production, trade, and consumption between 2005 and 2030. In particular, we simulate a closer cooperation of the GASPEC countries when exporting pipeline gas and liquefied natural gas; we also run a more drastic scenario where GASPEC countries deliberately withhold production. The results shows that compared to a Base Case, a gas cartel would reduce total supplied quantities and induce price increases in gas importing countries up to 22%. There is evidence that the natural gas markets in Europe and North America would be affected more than other parts of the world. Lastly, the vulnerability of gas importers worldwide on gas exporting countries supplies is further illustrated by the results of a sensitivity case in which price levels are up to 87% higher in Europe and North America, but non-GEC countries increase production by a mere 10%.natural gas, trade, cartel, collusion, World Gas Model

    The World Gas Market in 2030: Development Scenarios Using the World Gas Model

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    In this paper, we discuss potential developments of the world natural gas industry at the horizon of 2030. We use the World Gas Model (WGM), a dynamic, strategic representation of world natural gas production, trade, and consumption between 2005 and 2030. We specify a "base case" which defines the business-as-usual assumptions based on forecasts of the world energy markets. We then analyze the sensitivity of the world natural gas system with scenarios: i) the emergence of large volumes of unconventional North American natural gas reserves, such as shale gas; ii) on the contrary, tightly constrained reserves of conventional natural gas reserves in the world; and iii) the impact of CO2-constraints and the emergence of a competing environmental friendly "backstop technology". Regional scenarios that have a global impact are: iv) the full halt of Russian and Caspian natural gas exports to Western Europe; v) sharply constrained production and export activities in the Arab Gulf; vi) heavily increasing demand for natural gas in China and India; and finally vii) constraints on liquefied natural gas (LNG) infrastructure development on the US Pacific Coast. Our results show considerable changes in production, consumption, traded volumes, and prices between the scenarios. Investments in pipelines, LNG terminals and storage are also affected. However, overall the world natural gas industry is resilient to local disturbances and can compensate local supply disruptions with natural gas from other sources. Long-term supply security does not seem to be at risk.Natural gas, investments, reserves, climate policy

    Provider Self-Report and Practice: Reassessment and Referral of Emergency Department Patients With Elevated Blood Pressure

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    Background We attempted to identify patient factors associated with blood pressure (BP) reassessment and to compare health-care provider self-reported reassessment and referral to actual practice in an emergency department (ED) setting. Methods Provider reassessment and referral practices were determined through systematic review of 1,250 medical records at five EDs. Medical records were included if patients were ≄18 years, nonpregnant, presented with a systolic (SBP) ≄140 or diastolic BP (DBP) ≄90 mm Hg, and discharged. A separate questionnaire obtained self-reported practice patterns of health-care providers. Multivariate logistic regression identified factors associated with patient BP reassessment and referral. Results Of 1,250 patients, only 57% underwent BP reassessment and 9% received a referral for outpatient management. The most significant independent variables related to a reassessment were as follows: treatment of elevated BP in the ED (odds ratio (OR): 6.05; 95% confidence interval (CI): 1.80-20.31), chest pain (OR: 3.90; 95% CI: 2.37-6.42), and presence of an ED reassessment protocol (OR: 2.49; 95% CI: 1.77-3.50). The most significant factors associated with a referral included treatment of elevated BP in the ED (OR: 5.55; 95% CI: 2.72-11.32), presence of a reassessment protocol (OR: 2.58; 95% CI: 1.32-5.05), and a BP reassessment (OR: 2.56; 95% CI: 1.34-4.89). For self-reported practice patterns, 379 (72%) health-care providers completed questionnaires. Providers consistently overestimated their referral practices, yet the mean referral threshold values reported (SBP, 150 mm Hg; DBP, 93 mm Hg) were lower than the mean BP values of patients who actually received a directed referral (SBP, 170 mm Hg; DBP, 97 mm Hg, P < 0.0001). Conclusions Reassessment and referral of discharged ED patients with elevated BP was infrequent and health-care providers overestimate their reassessment and referral effort
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