852 resultados para Algorithme de Metropolis-Hastings
Resumo:
Cities have developed into the hotspots of human economic activity. From the appearance of the first cities in the Neolithic to 21st century metropolis their impact on the environment has always been apparent. With more people living in cities than in rural environments now it becomes crucial to understand these environmental impacts. With the immergence of megacities in the 20th century and their continued growth in both, population and economic power, the environmental impact has reached the global scale. In this paper we examine megacity impacts on atmospheric composition and climate. We present basic concepts, discuss various definitions of footprints, summarize research on megacity impacts and assess the impact of megacity emissions on air quality and on the climate at the regional to global scale. The intention and ambition of this paper is to give a comprehensive but brief overview of the science with regard to megacities and the environment.
Resumo:
The seasonal evolution of daily and hourly values of global and diffuse solar radiation at the surface are compared for the cities of Sao Paulo and Botucatu, both located in Southeast Brazil and representative of urban and rural areas, respectively. The comparisons are based on measurements of global and diffuse solar irradiance carried out at the surface during a six year simultaneous period in these two cities. Despite the similar latitude and altitude, the seasonal evolution of daily values indicate that Sao Paulo receives, during clear sky days, 7.8% less global irradiance in August and 5.1% less in June than Botucatu. On the other hand, Sao Paulo receives, during clear sky days, 3.6% more diffuse irradiance in August and 15.6% more in June than Botucatu. The seasonal variation of the diurnal cycle confirms these differences and indicates that they are more pronounced during the afternoon. The regional differences are related to the distance from the Atlantic Ocean, systematic penetration of the sea breeze and daytime evolution of the particulate matter in Sao Paulo. An important mechanism controlling the spatial distribution of solar radiation, on a regional scale, is the sea breeze penetration in Sao Paulo, bringing moisture and maritime aerosol that in turn further increases the solar radiation scattering due to pollution and further reduces the intensity of the direct component of solar radiation at the surface. Surprisingly, under clear sky conditions the atmospheric attenuation of solar radiation in Botucatu during winter - the biomass burning period due to the sugar cane harvest - is equivalent to that at Sao Paulo City, indicating that the contamination during sugar cane harvest in Southeast Brazil has a large impact in the solar radiation field at the surface.
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The multivariate skew-t distribution (J Multivar Anal 79:93-113, 2001; J R Stat Soc, Ser B 65:367-389, 2003; Statistics 37:359-363, 2003) includes the Student t, skew-Cauchy and Cauchy distributions as special cases and the normal and skew-normal ones as limiting cases. In this paper, we explore the use of Markov Chain Monte Carlo (MCMC) methods to develop a Bayesian analysis of repeated measures, pretest/post-test data, under multivariate null intercept measurement error model (J Biopharm Stat 13(4):763-771, 2003) where the random errors and the unobserved value of the covariate (latent variable) follows a Student t and skew-t distribution, respectively. The results and methods are numerically illustrated with an example in the field of dentistry.
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We describe the canonical and microcanonical Monte Carlo algorithms for different systems that can be described by spin models. Sites of the lattice, chosen at random, interchange their spin values, provided they are different. The canonical ensemble is generated by performing exchanges according to the Metropolis prescription whereas in the microcanonical ensemble, exchanges are performed as long as the total energy remains constant. A systematic finite size analysis of intensive quantities and a comparison with results obtained from distinct ensembles are performed and the quality of results reveal that the present approach may be an useful tool for the study of phase transitions, specially first-order transitions. (C) 2009 Elsevier B.V. All rights reserved.
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The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the mu g m(-3) range) and their variations with sampling site and time In this work a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE) a quick separation technique that requires nothing more than some nanoliters of sample and when combined with capacitively coupled contactless conductometric detection (C(4)D) is particularly favorable for ionic species that do not absorb in the UV-vis region like the target analytes formaldehyde formic acid acetic acid and ammonium The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry s constant such as formaldehyde and carboxylic acids or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8 3 nLs(-1)) while the sample was aspirated through the annular gap of the concentric tubes at 25 mLs(-1) A second unit in all similar to the CMDS was operated as a capillary membrane diffusion emitter (CMDE) generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS The fluids of the system were driven with inexpensive aquarium air pumps and the collected samples were stored in vials cooled by a Peltier element Complete protocols were developed for the analysis in air of NH(3) CH(3)COOH HCOOH and with a derivatization setup CH(2)O by associating the CMDS collection with the determination by CE-C(4)D The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot s reaction Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW) All techniques and methods of this work are in line with the green analytical chemistry trends (C) 2010 Elsevier B V All rights reserved
Resumo:
The Indian author Rabindranath Tagore was received like royalty during his visits to the West after winning the Nobel Prize in 1913. Dreams of foreign cultures offered a retreat from a complicated age. In a time when the West appeared to be living under threat of disintegration and when industrialism seemed like a cul-de-sac, he appeared to offer the promise of a return to a lost paradise, a spiritual abode that is superior to the restless Western culture. However, Tagore’s popularity faded rapidly, most notably in England, the main target of his criticism. Soon after Tagore had won the Nobel Prize, the English became indignant at Tagore’s anti-colonial attitude.Tagore visited Sweden in 1921 and 1926 and was given a warm reception. His visits to Sweden can be seen as an episode in a longer chain of events. It brought to life old conceptions of India as the abode of spirituality on earth. Nevertheless, interest in him was a relatively short-lived phenomenon in Sweden. Only a few of his admirers in Sweden appreciated the complexity of Tagore’s achievements. His “anathema of mammonism”, as a Swedish newspaper called it, was not properly received. After a steady stream of translations his popularity flagged towards the end of the 1920s and then almost disappeared entirely. Tagores visits in Sweden gave an indication that India was on the way to liberate itself from its colonial legacy, which consequently contributed to the waning of his popularity in the West. In the long run, his criticism of the drawbacks in the western world became too obvious to maintain permanent interest. The Russian author Fyodor Dostoyevskiy’s Crime and Punishment (1866) has enticed numerous interpretations such as the purely biographical approach. In the nervous main character of the novel, the young student Raskolnikov, one easily recognizes Dostoyevskiy himself. The novel can also be seen as a masterpiece of realistic fiction. It gives a broad picture of Saint Petersburg, a metropolis in decay. Crime and Punishment can also be seen as one of the first examples of a modern psychological novel, since it is focused on the inner drama of its main character, the young student Raskolnikov. His actions seem to be governed by mere coincidences, dreams and the spur of the moment. it seems fruitful to study the novel from a psychoanalytical approach. In his book Raskolnikov: the way of the divided towards unity in Crime and Punishment (1982), a Swedish scholar, Owe Wikström, has followed this line of interpretation all the way to Freud’s disciple C G Jung. In addition to this, the novel functions as an exciting crime story. To a large extent it is Viktor Sjklovskij and other Russian formalists from the 1920s and onwards who have taught the western audience to understand the specific nature of the crime story. The novel could be seen as a story about religious conversion. Like Lasarus in the Bible (whose story attracts a lot of attention in the novel) Raskolnikov is awakened from the dead, and together with Sonja he starts a completely new life. The theme of conversion has a special meaning for Dostoyevskiy. For him the conversion meant an acknowledgement of the specific nature of Russia itself. Crime and punishment mirrors the conflict between traditional Russian values and western influences that has been obvious in Russia throughout the history of the country. The novel reflects a dialogue that still continues in Russian society. The Russian literary historian Mikhail Bakhtin, who is probably the most famous interpreter of the works of Dostoyevskiy, has become famous precisely by emphasizing the importance of dialogues in novels like Crime and Punishment. According to Bakhtin, this novel is characterized by its multitude of voices. Various ideas are confronted with each other, and each one of them is personified by one of the characters in the novel. The author has resigned from his position as the superior monitor of the text, and he leaves it to the reader to decide what interpretation is the correct one..The aim of the present study is thus to analyze the complex reactions in the west to Tagore’s visits in Sweden and to Fyodor Dostoyevskiys novel Crime and Punishment.. This leads to more general conclusions on communication between cultures.
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O presente relatório discute uma das significativas dimensões da avenida Paulista na cidade de São Paulo: sua crescente ocupação para manifestações políticas, articuladas principalmente por categorias profissionais como bancários, funcionários públicos, professores e metalúrgicos, além de outras mais abrangentes como os protestos pelo impeachment, liderados por setores estudantis. O principal objetivo é analisar a visibilidade privilegiada adquirida por essas manifestações, e por conseguinte a importância desse espaço em sua dimensão pública na metrópole.
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This study discusses the preparation and execution of the Municipal Annual Budget Law of the City of Rio de Janeiro. It tries to show how the City historically evolved and how its administrative structure was built, leading to the offer of public services to a residing population of approximately six million people today. By using processes of supplementary credits to the Budget, comparing results of the budget execution along a four-year period and with charts related to these years, answers are searched to explain the reasons for amendments to the Annual Budget Law, which modify it and change part of its initial objectives, in spite of hours of previous planning work dedicated to its preparation. This research shows a City in its context and puts together a few data, through a survey of budget management actions, to report on the administrative complexity of metropolis like Rio de Janeiro, although without the intent of being definitive in terms of exhausting the issue.
Resumo:
Dentro do contexto do desenvolvimento urbano sustentável, diversas metrópoles estão revitalizando áreas centrais degradadas. Regiões portuárias são exemplos de áreas degradadas que têm passado por processos de revitalização. O envolvimento de diferentes atores locais (Poder Público, mercado e sociedade civil) no processo de decisão e também durante a implementação das obras de revitalização deve ser visto como ponto chave na garantia de um processo transparente e particular para cada revitalização executada. Para subsidiar tal abordagem, este trabalho utiliza como referencial teórico a gestão social e seus critérios do processo de discussão, pluralismo e bem-comum para a implementação de políticas públicas, onde a multiplicidade de atores deve participar em igualdade de direitos nos processos decisórios deliberativos na busca do bem-estar social. Na cidade do Rio de Janeiro, em 2009, a instituição por lei da Operação Urbana Consorciada da Área de Especial Interesse Urbanístico da Região Portuária do Rio de Janeiro garante que o projeto de revitalização chamado Porto Maravilha possa ser implementado. Por ser fruto de uma Operação Urbana Consorciada, o projeto deve contar com a participação de proprietários, moradores, usuários e dos investidores para revitalizar uma área de aproximadamente cinco milhões de metros quadrados. Assim, considerada a importância de diferentes atores para garantir um processo decisório legítimo e considerada a obrigatoriedade da participação de diferentes atores na implementação do projeto Porto Maravilha, o objetivo deste trabalho é identificar como as instituições locais participam no Projeto Porto Maravilha. Para tanto, realizou-se pesquisa de campo por meio da participação em reuniões das instâncias participativas na região portuária, da aplicação de questionários às instituições locais e da realização de entrevistas semiestruturadas com representantes das instituições locais e outros atores envolvidos com o projeto. Para o tratamento dos dados obtidos utilizou-se o método da análise de conteúdo com grade mista, cujas categorias definidas foram relacionadas com os critérios do processo de discussão, pluralismo e bem-comum da gestão social e um tratamento estatístico para a elaboração de uma matriz que permitiu relacionar o grau de participação e a posição das instituições locais frente ao projeto. Para o tratamento final, a triangulação metodológica foi utilizada e os resultados foram confrontados com o referencial teórico. Os resultados mostraram que a revitalização da região portuária despertou interesse para que instâncias participativas que já existiam na região se reestruturassem e que novas instâncias fossem criadas. Independente de serem a favor ou contra o projeto, há uma mobilização por parte das instituições locais em se envolverem no projeto, embora este não possa se caracterizar como um processo deliberativo de construção conjunta definido a partir de um consenso, pois, as diretrizes gerais do projeto Porto Maravilha foram instituídas por lei. A maioria das instituições locais concorda e participa do acompanhamento e da implementação do projeto por meio do compartilhamento com o Estado da responsabilidade de criar espaços educativos e investir em programas sociais que possam garantir a melhoria das condições de vida da população local.