993 resultados para 371.03


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Esta dissertação tem o objetivo investigar as representações do universo mítico-religioso de matriz africana na formação de professores, no âmbito do curso normal, a partir da observação participante em duas escolas da rede pública estadual do Rio de Janeiro. Pretende-se apurar se entraves à aplicação da Lei 10.639/2003 (bem como a Resolução 01/2004 do CNE/CP e Parecer CNE/CP 03/2004), que visa cumprir o que estabelece o Plano Nacional de Implementação das Diretrizes Curriculares Nacionais para a Educação das Relações Étnico-raciais e para o Ensino de História e Cultura Afro-Brasileira e Indígena, podem ser identificados no plano objetivo da capacidade técnica dos professores e/ou no plano subjetivo, no qual se retrairiam as ações orientadas nessa direção em face de limites de natureza ideológica. O principal desafio proposto é o de revelar, no discurso e nos atos, intencionais ou não, de educadores que formam novos educadores, os limites ideológicos à aplicação da legislação em questão, e que vicejam nas ações e reações em sala de aula.

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Inúmeras são as formas de entendermos uma imagem, analisando as mesmas dentro de uma coleção didática de historia de segundo segmento, procuramos analisar de maneira imparcial e coerente o impacto gerado pela lei 10639/03 sobre tal material e seus objetivos quanto à resignificação do negro dentro da história do Brasil. Para isso abrimos dialogo com teóricos que nos auxiliaram a entender a amplitude do conceito de imagem, tal como buscamos o debate a cerca da importância da mesma para o ensino de história, para tal buscamos mapear as atividades legislativas relacionadas à referida lei, e os programas governamentais que fomentam a produção editorial didática no Brasil. Diante desse caminho enfrentamos caminhos tortuosos e contraditórios, mas que nos levaram a deliberar a necessidade de novos estudos, esses mais amplos no que concerne o campo de pesquisa e mais aprofundado no que se refere ao próprio conceito de imagem, e a questão de resignificação do negro. Contudo podemos dizer que a presente pesquisa se mostra um material que como o próprio título refere-se contribuído para o estudo da imagem do negro e percebemos os avanços e permanências encontrados nos livros didáticos de historia após o ano de 2003.

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The objectives of the workshop were to; ensure shark catches were sustainable; assess threats to shark populations; identify vulnerable shark stocks; protect biodiversity; improve consultation involving stakeholders; minimize waste a discards and facilitate monitoring and landings data.

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Material efficiency, as discussed in this Meeting Issue, entails the pursuit of the technical strategies, business models, consumer preferences and policy instruments that would lead to a substantial reduction in the production of high-volume energy-intensive materials required to deliver human well-being. This paper, which introduces a Discussion Meeting Issue on the topic of material efficiency, aims to give an overview of current thinking on the topic, spanning environmental, engineering, economics, sociology and policy issues. The motivations for material efficiency include reducing energy demand, reducing the emissions and other environmental impacts of industry, and increasing national resource security. There are many technical strategies that might bring it about, and these could mainly be implemented today if preferred by customers or producers. However, current economic structures favour the substitution of material for labour, and consumer preferences for material consumption appear to continue even beyond the point at which increased consumption provides any increase in well-being. Therefore, policy will be required to stimulate material efficiency. A theoretically ideal policy measure, such as a carbon price, would internalize the externality of emissions associated with material production, and thus motivate change directly. However, implementation of such a measure has proved elusive, and instead the adjustment of existing government purchasing policies or existing regulations-- for instance to do with building design, planning or vehicle standards--is likely to have a more immediate effect.

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Steel production is energy intensive so already has achieved impressive levels of energy efficiency. If the emissions associated with steel must be reduced in line with the requirements of the UK Climate Change Act, demand for new steel must be reduced. The strategies of 'material efficiency' aim to achieve such a reduction, while delivering the same final services. To meet the emissions targets set into UK law, UK consumption of steel must be reduced to 30 per cent of present levels by 2050. Previous work has revealed six strategies that could contribute to this target, and this paper presents an approximate analysis of the required transition. A macro-economic analysis of steel in the UK shows that while the steel industry is relatively small, the construction and manufacturing sectors are large, and it would be politically unacceptable to pursue options that lead to a major contraction in other sectors. Alternative business models are therefore required, and these are explored through four representative products--one for each final sector with particular emphasis given to options for reducing product weight, and extending product life. Preliminary evidence on the triggers that would lead to customers preferring these options is presented and organized in order to predict required policy measures. The estimated analysis of transitions explored in this paper is used to define target questions for future research in the area.

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In this paper, we review the energy requirements to make materials on a global scale by focusing on the five construction materials that dominate energy used in material production: steel, cement, paper, plastics and aluminium. We then estimate the possibility of reducing absolute material production energy by half, while doubling production from the present to 2050. The goal therefore is a 75 per cent reduction in energy intensity. Four technology-based strategies are investigated, regardless of cost: (i) widespread application of best available technology (BAT), (ii) BAT to cutting-edge technologies, (iii) aggressive recycling and finally, and (iv) significant improvements in recycling technologies. Taken together, these aggressive strategies could produce impressive gains, of the order of a 50-56 per cent reduction in energy intensity, but this is still short of our goal of a 75 per cent reduction. Ultimately, we face fundamental thermodynamic as well as practical constraints on our ability to improve the energy intensity of material production. A strategy to reduce demand by providing material services with less material (called 'material efficiency') is outlined as an approach to solving this dilemma.

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Wafers with normal light-emitting diode structure were grown by metal organic chemical vapor deposition system. The pressure and temperature were varied during growth of buffer layer in order to grow different types of epilayers. The cathodoluminescence results show that the interface distortion of quantum well plays an important role in radiant efficiency. The electroluminescence detections indicate that the dislocations also influence the external quantum efficiency by lowering the electron injection efficiency. (c) 2006 Elsevier Ltd. All rights reserved.

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介绍了在AlGaAs/GaAs太阳电池上制备MgF_2/ZnS双层减反射膜的研究工作。引入了有效反射率R_e,并通过使R_e极小来实现减反射膜的优化设计,考虑了MgF_2/ZnS双层减反射膜与窗口层的耦合。实验上获得了良好的减反射膜,提高了AlGaAs/GaAs太阳电池的短路电流和效率,表明用R_e极小化来设计减反射膜是合理的。

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景观边界是特定时空尺度下相对均质的景观之间所存在的异质性过渡带,作为景观的一个四维组分,边界动态直接反映景观变化,与基于斑块的研究相比,明确景观边界的生态意义是理解景观过程的一个新的切入点。边界效应是景观边界最显著特征之一,也是当前生态学领域的研究热点,但大部分研究集中在生态系统及其以下尺度,对大尺度上的研究涉及内容尚少。 本文以岷江上游地区为例,利用TM影像数据、林相图、土地利用图和野外实测数据,应用RS、GIS、SPSS、Fragstats等软件的数据处理、分析、运算功能,研究了景观边界网络格局的变化,并分析了与之相关的生态过程;研究了类型水平上森林景观的边界效应以及景观尺度上林农复合景观的边界网络效应。旨在揭示岷江上游景观格局的变化趋势及其驱动因子,以及林农复合景观格局的生态效应,从而为研究区土地利用提供科学参考。研究结果如下: (一)在岷江上游地区的13种景观边界类型中,建筑用地边界和农田边界是人工边界,同时也都是清晰边界;但林地、灌木林地、草地等自然景观之间的边界并不都是模糊边界。冰雪边界是典型的随季节变化的变动型边界,其它边界在年内的变化则相对稳定。 (二)在1974-2000年期间,由于人为干扰强度的加剧,岷江上游景观边界网络结构变得更加复杂,在早期以边界长度增加为主,网络连接度变大,在后期以边界数量和结点数量增加为主,网络连接度变小;森林景观与低坡位景观类型间的边界减少,森林下线上移;农田与林地的边界在早期增加,1986年后减少,而与灌木林地的边界持续增加;基于边界特征的格局分析表明,森林景观结构变得简单化,而农田、灌木林地、草地等景观类型的结构变得更加复杂。 在景观水平上,基于边界和结点特征的格局指数与对应的基于斑块特征的格局指数具有基本一致的变化趋势,但基于边界和结点特征的指数对格局的变化更灵敏,在类型水平上,基于结点的格局指数比基于边界的格局指数具有更大的灵敏性,而且前者能够反映出后者反映不出的格局信息。 (三)研究区的农田边界共有5种类型,分别是农田与林地、灌木林地、草地、水体、建筑用地之间的边界,总长6583.4km;其中林农边界长2473.7km,占37.6%,是除灌农边界(占农田边界总长度的44.9%)之外比例最大的农田边界类型,广泛分布在岷江干流及其支流的河谷中,海拔多在1000-3500m之间。 (1)多元线性回归分析结果表明,农田生物量的边界效应深度与海拔和坡度显著相关,与其它因子相关性不大;林地生物量的边界效应深度与海拔和坡向相关性较大,与其它因子相关性不大;林农边界对农田生物量产生正面效应,对林地生物量产生负面效应,且对农田的影响面积大于对林地的影响面积;根据回归方程计算边界效应的影响面积,2000年有14532hm2林地生物量受到林农边界网络的影响,占研究区林地面积的1.2%,有16659 hm2农田生物量受到林农边界网络的影响,占研究区农田面积的22.6%,由于边界位置、长度的变化,不同年间林农边界网络的生态效应也存在差异。 除了生物量,本文还研究了林农边界网络对林地和农田土壤水分和生物多样性的影响: (2)林农边界减少林地和农田边缘的土壤水分,岷江上游有2103 hm2农田和371 hm2林地其土壤水分受到林农边界效应的影响,分别占研究区农田面积的2.3%和林地面积的0.03%。生物多样性受林农边界网络影响的农田面积为4855 hm2,占研究区农田面积的5.37%;生物多样性受林农边界网络影响的林地面积为3401 hm2,占研究区林地面积的0.29%。 上述研究从景观边界网络的角度揭示了岷江上游近三十年的景观变化特征,在印证斑块类型所反映的景观变化特征的同时,还反映出传统格局研究方法反映不出的格局信息,为景观生态学中格局与过程研究提供了新思路,也丰富了边界效应的理论和案例研究,有关结论还可为高山峡谷区土地利用格局优化和实施退耕还林还草工程提供参考依据。

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阐述了利用微机对ZHT-03质谱仪电测量部分进行改造的原理及方法,实现了电场扫描电压的自动控制,离子流质量峰的自动采集和数据的自动处理,提高了测量精度。实际应用证明,各项指标均优于原仪器。