Teoria de carteiras e a alocação de parques eólicos offshore

The consumption of energy on the planet is currently based on fossil fuels. They are responsible for adverse effects on the environment. Renewables propose solutions for this scenario, but must face issues related to the capacity of the power supply. Wind energy offshore emerging as a promising alternative. The speed and stability are greater winds over oceans, but the variability of these may cause inconvenience to the generation of electric power fluctuations. To reduce this, a combination of wind farms geographically distributed was proposed. The greater the distance between them, the lower the correlation between the wind velocity, increasing the likelihood that together achieve more stable power system with less fluctuations in power generation. The efficient use of production capacity of the wind park however, depends on their distribution in marine environments. The objective of this research was to analyze the optimal allocation of wind farms offshore on the east coast of the U.S. by Modern Portfolio Theory. The Modern Portfolio Theory was used so that the process of building portfolios of wind energy offshore contemplate the particularity of intermittency of wind, through calculations of return and risk of the production of wind farms. The research was conducted with 25.934 observations of energy produced by wind farms 11 hypothetical offshore, from the installation of 01 simulated ocean turbine with a capacity of 5 MW. The data show hourly time resolution and covers the period between January 1, 1998 until December 31, 2002. Through the Matlab R software, six were calculated minimum variance portfolios, each for a period of time distinct. Given the inequality of the variability of wind over time, set up four strategies rebalancing to evaluate the performance of the related portfolios, which enabled us to identify the most beneficial to the stability of the wind energy production offshore. The results showed that the production of wind energy for 1998, 1999, 2000 and 2001 should be considered by the portfolio weights calculated for the same periods, respectively. Energy data for 2002 should use the weights derived from the portfolio calculated in the previous time period. Finally, the production of wind energy in the period 1998-2002 should also be weighted by 1/11. It follows therefore that the portfolios found failed to show reduced levels of variability when compared to the individual production of wind farms hypothetical offshore

Criação em processo no espetáculo Ethnotron-Ghetto Experimen

Este trabalho investigou o processo criativo do espetáculo Ethnotron-Ghetto Experiment, do Coletivo paraibano Tribo Éthnos, fundado na década de 1990 e ainda em atividade. A estratégia metodológica se dá através de estudos descritivos, valendo-se da teoria e prática de diversas linguagens artísticas presentes na obra apontada: artes visuais, performance, literatura e histórias em quadrinho; em ações realizadas pelo Coletivo ao longo dos anos, objetivando descrever e analisar o processo de criação do referido espetáculo de dança, através da minuciosa coleta de dados por meio de entrevistas abertas e semiestruturadas, e da pesquisa e captação de materiais audiovisuais. A Tribo Éthnos destaca-se na cena local na cidade de João Pessoa, e estadual, na Paraíba, visto que, nesse longo percurso de existência, além da preocupação em fundir muitas formas artísticas, bem como os artistas da Paraíba, aglutina pessoas que fazem arte em outros países e faz das danças urbanas algo instigante. A Tribo ainda preocupa-se com a troca de saberes através de palestras, oficinas, cursos e intercâmbios. A dissertação investiga o processo de criação dos artistas e, especificamente, dos dançarinos, utilizando-se principalmente do conceito de work in progress, proposto por Renato Cohen, e aplicado ao espetáculo estudado. Apresentam-se descrições dos movimentos coreográficos, do espetáculo de dança paraibano Ethnotron-Ghetto Experiment, de Dança de Rua da Era Funky, especificamente, com estilos como popping, waving, animation, strobing, floatine/ slidini, tiokine, trebing, breaking, waving, sliding, entre outros, visto serem estes parte integrante do processo de criação. Tais estilos remetem ao ilusionismo ou ao mimetismo, sugerindo, em seus movimentos truques, câmeras lentas, flutuações com os pés, entre outros. Segundo Valmir Vaz, o Coletivo, através do espetáculo, busca a integração dos corpos, procura uma libertação individual e sugere uma sensação de querer voar nas coreografias/cenas. Abordam-se os aspectos do processo criativo: o espaço cênico, o trabalho corporal, a sonoplastia e a roupa/indumentária. Trabalha-se o conceito do corpo virtual de José Gil no aspecto do corpo cênico

Variação temporal da Comunidade de macroinvertebrados bentônicos em um riacho intermitente do semiárido brasileiro

In Brazilian semiarid region, the majority of water bodies are temporary and the biodiversity in these ecosystems is poorly known. The goal of this study was to describe the temporal variation of benthic macroinvertebrates in an intermittent stream in the Brazilian semiarid region. From March to July of 2009, surveys of benthic macroinvertebrates and water physiochemical parameters were done in a first order stream located at Piranhas-Açu River basin. 25 macroinvertebrates families were found, 21 belonging to Insecta class. The chironomids were the most abundant group during all study period and were represented by 19 genus. The largest densities and taxonomic richness were seen in the drying phase of the stream while the smallest values were found in the period with the heaviest rainfalls ( wet phase ). Only the families Chironomidae and Ceratopogonidae were found during all study period, suggesting that these groups have better adaptations to support floods and droughts. Furthermore, these two groups seemed to be pioneering in this stream. Among the chironomids, Paratendipes dominated the period of floods while Tanytarsus were more abundant in the drying phase . This study showed that hydrological fluctuation is the main force influencing the macroinvertebrate community in this stream, therefore, efforts seeking the conservation and management of Brazilian semiarid water bodies should consider this high natural variability in flow regime