1,112 research outputs found

    A Forward Looking Version of the MIT Emissions Prediction and Policy Analysis (EPPA) Model

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    Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).This paper documents a forward looking multi-regional general equilibrium model developed from the latest version of the recursive-dynamic MIT Emissions Prediction and Policy Analysis (EPPA) model. The model represents full inter-temporal optimization (perfect foresight), which makes it possible to better address economic and policy issues such as borrowing and banking of GHG allowances, efficiency implications of environmental tax recycling, endogenous depletion of fossil resources, international capital flows, and optimal emissions abatement paths among others. It was designed with the flexibility to represent different aggregations of countries and regions, different horizon lengths, as well as the ability to accommodate different assumptions about the economy, in terms of economic growth, foreign trade closure, labor leisure choice, taxes on primary factors, vintaging of capital and data calibration. The forward-looking dynamic model provides a complementary tool for policy analyses, to assess the robustness of results from the recursive EPPA model, and to illustrate important differences in results that are driven by the perfect foresight behavior. We present some applications of the model that include the reference case and its comparison with the recursive EPPA version, as well as some greenhouse gas mitigation cases where we explore economic impacts with and without inter-temporal trade of permits.This research was supported by the U.S Department of Energy, U.S. Environmental Protection Agency, U.S. National Science Foundation, U.S. National Aeronautics and Space Administration, U.S. National Oceanographic and Atmospheric Administration; and the Industry and Foundation Sponsors of the MIT Joint Program on the Science and Policy of Global Change: Alstom Power (USA), American Electric Power (USA), A.P. Møller-Maersk (Denmark), Cargill (USA), Chevron Corporation (USA), CONCAWE & EUROPIA (EU), DaimlerChrysler AG (USA), Duke Energy (USA), Electric Power Research Institute (USA), Electricité de France, Enel (Italy), Eni (Italy), Exelon Power (USA), ExxonMobil Corporation (USA), Ford Motor Company (USA), General Motors (USA), Iberdrola Generacion (Spain), J-Power (Japan), Merril Lynch (USA), Murphy Oil Corporation (USA), Norway Ministry of Petroleum and Energy, Oglethorpe Power Corporation (USA), RWE Power (Germany), Schlumberger (USA),Shell Petroleum (Netherlands/UK), Southern Company (USA), StatoilHydro (Norway), Tennessee Valley Authority (USA), Tokyo Electric Power Company (Japan), Total (France), G. Unger Vetlesen Foundation (USA)

    Ciencias sociais como metodologia do ensino de currículos CTS

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    O diálogo entre Ciências Sociais e Ciências da Natureza na abordagem de currículos CTS ainda é muito tímido em publicações sobre Educação em Ciências. Neste trabalho são apresentados referenciais de contexto, no âmbito da história social da Ciência e da Tecnologia, que podem contribuir para uma metodologia de ensino mais ampla e crítica sobre os determinantes e as contradições do processo de evolução da C&T. Dentre os referenciais dos resultados identificamos: controle social, político, econômico, ético e de gestão e mercado da C&T. Esses são alguns dos elementos essenciais das Ciências Sociais para uma educação CTS de pensar complexo para orientar as necessidades sociais relacionadas à C&T em uma sociedade em transformação

    Phonoaudiological findings in patients submitted to hypoglossal-facial anastomosis

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    The hypoglossal-facial anastomosis (HFA) have been related in patients with facial nerve lesion where proximal segment more other surgical produceres had been faited or had not been possible success. AIM: The objective of the present research is to verify the evidence of mobility in the phonoarticulate organs, speech function, chew and swallowing in patients sujected to HFA. STUDY DESIGN: Clinical prospective. MATERIAL AND METHOD: Eight patients with peripheral facial paralysis (PFP) were evaluated and subjected to HFA at UNIFESP/EPM in the period from 1989 to 2000, with 6 females and 2 males, aged between 21 and 71 years with an average of 50 years. Of these, 5 after exeresis of Acoustic Neurinoma, 1 after exeresis of Fibrosarcoma, 1 after a gunshot wound and 1 after idiopathic peripheral facial paralysis of poor evolution. In the phonoaudiological evaluation, the protocol used involved identification data; classification of the facial nerve; treatments carried out; facial symmetry in repose and on voluntary movement; synhinesis of the eyes, mouth, nose and cheeks; phonoarticulate and tongue disorders; changes in chew and of the palate and a questionary concerning the appearence of the respective disturbances. RESULTS: The degree of pos anastomosis and reabilitation ranged to the eyes between II and V and to the mouth between III and V (House & Brakemann, 1985). We came to the conclusion that the recover was satisfactory and important but patients'recover expectation were inferior. There have been noted: articulatory imprecision chewing disfunction, deficit sphincteral function of oral muscles and disphage.A anastomose hipoglosso-facial (AHF) tem sido realizada em pacientes com lesão dos segmentos mais proximais do nervo facial em que outros procedimentos cirúrgicos não foram possíveis ou não obtiveram êxito. OBJETIVO: O objetivo atual da pesquisa é verificar as alterações na mobilidade dos órgãos fonoarticulatórios, quanto à função da fala, mastigação e da deglutição, em pacientes submetidos a AHF. FORMA DE ESTUDO: Clínico prospectivo. MATERIAL E MÉTODO: Foram avaliados 8 pacientes, com paralisia facial periférica (PFP), submetidos a AHF, na UNIFESP/EPM, no período de 1998 a 2000, sendo 6 do sexo feminino e 2 do sexo masculino, idades entre 21 e 71 anos e mediana de 50 anos. Desses, 5 pós-exerése do Schwannoma do Nervo Vestibular, 1 pós-exerése de Fibrossarcoma, 1 pós-ferimento por arma de fogo e 1 pós-paralisia facial idiopática de má evolução. Na avaliação fonoaudiológica, o protocolo consta de: dados de identificação; classificação da recuperação do nervo facial; tratamentos realizados; simetria facial no repouso e no movimento voluntário; sincinesias para olho, boca, nariz e bochechas; distúrbios fonoarticulatórios e da motricidade da língua; alteração na mastigação e do paladar, e questionário referente ao parecer dos respectivos distúrbios para serem respondidos pelo paciente. RESULTADO: O grau de paralisia pós-anastomose e reabilitação variou para os olhos entre II e V e para a boca entre III e V (House & Brackemann, 1985). Concluímos que recuperação foi satisfatória e importante, mas a expectativa de melhora foi inferior ao esperado pelos pacientes. Foram observados: imprecisão articulatória, disfunção mastigatória, escape bucal de alimentos e disfagia.Universidade Federal de São Paulo (UNIFESP) Campo FonoaudiológicoUniversidade Bandeirantes de São Paulo Ciências da Reabilitação Neuro-MotoraUniversidade Federal de São Paulo (UNIFESP)Universidade Federal de São Paulo (UNIFESP) EPM Disciplina de OtorrinolaringologiaUNIFESP, Campo FonoaudiológicoUNIFESP, EPM, Disciplina de OtorrinolaringologiaSciEL

    Coeficiente de variação como critério de avaliação em experimentos de milho.

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    O objetivo deste trabalho foi verificar se o Coeficiente de Variação (CV) é realmente o critério adequado para descarte de experimento, qual o valor mais apropriado para o CV e se há alternativas que aumentem a eficiência do processo. Foram utilizados dados dos Ensaios Nacionais de Milho cedidos pela EMBRAPA Milho e Sorgo, que consistiram em 566 experimentos conduzidos no período de 1993 a 2000. Os fatores fornecidos para a cultura do milho foram: número de cultivares, número de blocos, variância genética, média de produtividade e o coeficiente de variação. Foram simuladas 2.000 repetições para cada configuração da combinação desses fatores em um ambiente de programação Delphi. Foram simulados ensaios de campo considerando um delineamento em blocos casualizados completos (DBC). Concluiu-se que o coeficiente de variação não é um estimador confiável para a avaliação da eficiência de uma cultivar em um ensaio, devendo estar associado a outros parâmetros para tornar a recomendação de uma cultivar mais confiável; a repetibilidade é o parâmetro que, tendo-se definido os seus valores para cada variável-resposta, possibilitará definir critérios de descarte de experimentos de avaliação e recomendação de cultivares

    Precisão experimental em experimentos de VCU na cultura do feijão.

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    O objetivo deste trabalho foi verificar se o Coeficiente de Variação (CV) é realmente o critério adequado para descarte de experimento, qual o valor mais apropriado para o CV e se há alternativas que aumentem a eficiência do processo. Para se conhecer quais as variáveis mais importantes e os limites a serem utilizados na simulação, foi realizado inicialmente o levantamento de alguns dados experimentais com a cultura do feijão. Foram utilizados os dados da avaliação de linhagens de feijoeiro conduzidas pela UFLA/EPAMIG no período de 11 anos (1991 a 2001), totalizando 104 experimentos. Os fatores fornecidos foram: número de cultivares, número de blocos, variância genética, média de produtividade e o coeficiente de variação. Foram simuladas 2.000 repetições para cada configuração da combinação desses fatores. Todas estas informações foram processadas por meio de um aplicativo computacional desenvolvido em um ambiente de programação Delphi. Foram simulados ensaios de campo considerando um delineamento em blocos casualizados completos (DBC). Concluiu-se que o coeficiente de variação não é um estimador confiável para a avaliação da eficiência de uma cultivar em um ensaio, devendo estar associado a outros parâmetros para tornar a recomendação de uma cultivar mais confiável; a repetibilidade é o parâmetro que, tendo-se definido os seus valores para cada variável-resposta, possibilitará definir critérios de descarte de experimentos de avaliação e recomendação de cultivares

    Unintended Environmental Consequences of a Global Biofuels Program

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    Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).Biofuels are being promoted as an important part of the global energy mix to meet the climate change challenge. The environmental costs of biofuels produced with current technologies at small scales have been studied, but little research has been done on the consequences of an aggressive global biofuels program with advanced technologies using cellulosic feedstocks. Here, with simulation modeling, we explore two scenarios for cellulosic biofuels production and find that both could contribute substantially to future global-scale energy needs, but with significant unintended environmental consequences. As the land supply is squeezed to make way for vast areas of biofuels crops, the global landscape is defined by either the clearing of large swathes of natural forest, or the intensification of agricultural operations worldwide. The greenhouse gas implications of land-use conversion differ substantially between the two scenarios, but in both, numerous biodiversity hotspots suffer from serious habitat loss. Cellulosic biofuels may yet serve as a crucial wedge in the solution to the climate change problem, but must be deployed with caution so as not to jeopardize biodiversity, compromise ecosystems services, or undermine climate policy.This study received funding from the MIT Joint Program on the Science and Policy of Global Change, which is supported by a onsortium of government, industry and foundation sponsors

    U.S. Greenhouse Gas Cap-and-Trade Proposals: Application of a Forward-Looking Computable General Equilibrium Model

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    Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).We develop a forward-looking version of the MIT Emissions Prediction and Policy Analysis (EPPA) model, and apply it to examine the economic implications of proposals in the U.S. Congress to limit greenhouse gas (GHG) emissions. We find that the abatement path and CO2-equivalent (CO2-e) price in the forward-looking model are quite similar to that of the recursive model, implying that the simulation of banking behavior in the recursive model by forcing the CO2-e price to rise at the discount rate approximates fairly well the banking result obtained with the forward-looking model. We find, however, that shocks in consumption path are smoothed out in the forward-looking model and that the lifetime welfare cost of GHG policy is lower than in the recursive model, results we would expect to find given that the forward-looking model can fully optimize over time. The forward-looking model allows us to explore issues for which it is uniquely well-suited, including revenue-recycling, early action crediting, and the role of a technology backstop. We find (1) capital tax recycling to be more welfare-cost reducing than labor tax recycling because of its long term effect on economic growth, (2) potentially substantial incentives for early action credits relative to emission levels in years after a policy is announced but before it is implemented that, however, when spread over the full horizon of the policy do not have a substantial effect on lifetime welfare cost or the CO2-e price, and (3) strong effects on estimates of near-term welfare costs depending on exactly how a backstop technology is represented, indicating the problematic aspects of focusing on short-term welfare costs in a forward-looking model unless there is some confidence that the backstop technology is realistically represented.This study received support from the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsors

    Assessment of U.S. Cap-and-Trade Proposals

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    The MIT Emissions Prediction and Policy Analysis model is applied to synthetic policies that match key attributes of a set of cap-and-trade proposals being considered by the U.S. Congress in spring 2007. The bills fall into two groups: one specifies emissions reductions of 50% to 80% below 1990 levels by 2050; the other establishes a tightening target for emissions intensity and stipulates a time-path for a "safety valve" limit on the emission price that approximately stabilizes U.S. emissions at the 2008 level. Initial period prices are estimated between 7and7 and 50 per ton CO2-e with these prices rising by a factor of four by 2050. Welfare costs vary from near zero to less than 0.5% at the start, rising in the most stringent case to near 2% in 2050. If allowances were auctioned these proposals could produce revenue between 100billionand100 billion and 500 billion per year depending on the case. Outcomes from U.S. policies depend on mitigation effort abroads, and simulations are provided to illuminate terms-of-trade effects that influence the emissions prices and welfare effects, and even the environmental effectiveness, of U.S. actions. Sensitivity tests also are provided of several of key design features. Finally, the U.S. proposals, and the assumptions about effort elsewhere, are extended to 2100 to allow exploration of the potential role of these bills in the longer-term challenge of reducing climate change risk. Simulations show that the 50% to 80% targets are consistent with global goals of atmospheric stabilization at 450 to 550 ppmv CO2 but only if other nations, including the developing countries, follow suit.
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