6,855 research outputs found
Anisotropic simplicial minisuperspace model
The computation of the simplicial minisuperspace wavefunction in the case of
anisotropic universes with a scalar matter field predicts the existence of a
large classical Lorentzian universe like our own at late timesComment: 19 pages, Latex, 6 figure
Simplicial minisuperspace models in the presence of a massive scalar field with arbitrary scalar coupling
We extend previous simplicial minisuperspace models to account for arbitrary
scalar coupling \eta R\phi^2.Comment: 24 pages and 9 figures. Accepted for publication by Classical and
Quantum Gravit
Project MARIE: presentation and stage of development
Project MARIE - Mediterranean Building Rethinking for Energy Efficiency Improvement is an international strategic project from the European Union in the scope of the MED Program. The project aims to promote building energy efficiency in the Mediterranean region and overcome the mains barriers to large scale improvement trough the development of a common strategy adaptable to each country/region specifications, in the framework of European Union building energy efficiency policies. This article presents a description of the Project MARIE, its stage of development, and also the results achieved in the first third of the project
Proposta de nova metodologia para o cálculo do fator de sombreamento de vãos envidraçados por elementos horizontais
O comportamento térmico dos edifícios depende, em larga medida, dos ganhos solares verificados através dos vãos envidraçados. Devem os ganhos solares ser otimizados, isto é, durante a estação de aquecimento, os ganhos solares úteis devem ser maximizados e, durante a estação de arrefecimento, as cargas térmicas devidas aos ganhos solares devem ser minimizadas.
Os dispositivos de sombreamento dos vãos envidraçados, devem, tanto quanto possível, provocar o sombreamento dos vãos, durante a estação de arrefecimento e, na medida do possível, não o provocar durante a estação de aquecimento. As palas horizontais para sombreamento de vãos envidraçados são particularmente adequadas a vãos orientados a sul. As palas devem ser dimensionadas de forma a, tanto quanto possível, provocarem o sombreamento dos vãos envidraçados durante a estação de arrefecimento sem que tal aconteça durante a estação de aquecimento.
No entanto, verifica-se que, de uma forma geral, segundo a metodologia de cálculo prevista pelo Regulamento das Caraterísticas de Comportamento Térmico dos Edifícios (RCCTE), a existência de palas horizontais de sombreamento é penalizadora da eficiência energética dos edifícios. Com a presente comunicação, é apresentada uma nova metodologia de cálculo do factor de sombreamento por elementos horizontais. Através desta metodologia, desde que as palas horizontais sejam adequadamente dimensionadas, a sua existência originará necessidades nominais globais de energia primária de um edifício (Ntc) com um valor inferior ao que se obteria se não existissem as referidas palas. Consequentemente, a introdução de palas de sombreamento convenientemente dimensionadas contribuirá para a obtenção de uma mais elevada classe de eficiência energética do edifício
Comportamento acústico de salas para o ensino musical no Algarve. A perspetiva dos professores
Rooms for music education have specific requirements, in particular, from the point of view of its acoustic behavior. However, Regulation of Acoustic Requirements of Buildings establishes requirements for school buildings but does not consider the specificity of music schools buildings. Furthermore, there are music schools in buildings that were not constructed for such purpose and it is necessary to rehabilitate acoustically these buildings.
The present communication aims to present the diagnosis of specific problems in buildings for music education in Algarve and it is presented the point of view of their teachers. The aim is thus to contribute to solving these problems. Thus we want to contribute to improve the teaching-learning process in existing music schools and simultaneously to contribute to avoid the repetition of problematic situations in the future
An analysis of the potentialities of portuguese vernacular architecture to improve energy efficiency
Vernacular architecture is characterised by a type of formal expression that has been developed in response to a number of factors â climatic, lithologic, cultural and economic â characterising the local area or region. In its various forms, a range of techniques has been employed in different regions to mitigate the effects of climate. Despite the fact that Portugal is a small country, it has a territory full of contrasts, which gave origin to many different architectural manifestations. The approaches adopted in the design and construction of vernacular buildings have the potential for further development and could be adapted in response to contemporary needs. In the future, a blend of tradition and modernity should be aimed at in order to develop a new form of aesthetics and functional construction. Portuguese vernacular architecture is associated with a fund of valuable knowledge that should be studied and aligned with the principles of sustainability. In this paper, is presented the climatic contrast between the northern and southern parts of Portugal and the relation with the purpose of different passive solar techniques used in vernacular architecture to provide comfort. The focus is on the effectiveness of passive cooling techniques (e.g. high thermal inertia, the use of light colours and patios), and the findings of a case study in which the thermal performance during the summer of a vernacular residential building located in the south of Portugal are presented. In the context of the current global drive for clean energy and sustainable buildings, much can be learned from a review of past experience in order to provide an understanding of such forms of construction, which are an intrinsic feature of specific places and have evolved over time in the face of a lack of resources
Trajetória das Reformas Institucionais da Indústria Elétrica Brasileira e Novas Perspectivas de Mercado
This paper aims at presenting electricity negotiation alternatives in Brazil, which have resulted from a decade of structural and institutional reforms. With the purpose of achieving that, the specific characteristics of the Brazilian electric industry, the international experience and the historical restructuring processes witnessed by Brazil are going to be described, so that mistakes and solutions can be high lightened. As a consequence, it is expected that a wider picture not only of the new commercial and institutional environment in the country but also of the new perspectives faced by the agents in the electric sector is created.Regulaçãao Econômica, Indústria de Energia Elétrica Brasileira
New steroidal aromatase inhibitors: Suppression of estrogen-dependent breast cancer cell proliferation and induction of cell death
<p>Abstract</p> <p>Background</p> <p>Aromatase, the cytochrome P-450 enzyme (CYP19) responsible for estrogen biosynthesis, is an important target for the treatment of estrogen-dependent breast cancer. In fact, the use of synthetic aromatase inhibitors (AI), which induce suppression of estrogen synthesis, has shown to be an effective alternative to the classical tamoxifen for the treatment of postmenopausal patients with ER-positive breast cancer. New AIs obtained, in our laboratory, by modification of the A and D-rings of the natural substrate of aromatase, compounds <b>3a </b>and <b>4a</b>, showed previously to efficiently suppress aromatase activity in placental microsomes. In the present study we have investigated the effects of these compounds on cell proliferation, cell cycle progression and induction of cell death using the estrogen-dependent human breast cancer cell line stably transfected with the aromatase gene, MCF-7 aro cells.</p> <p>Results</p> <p>The new steroids inhibit hormone-dependent proliferation of MCF-7aro cells in a time and dose-dependent manner, causing cell cycle arrest in G<sub>0</sub>/G<sub>1 </sub>phase and inducing cell death with features of apoptosis and autophagic cell death.</p> <p>Conclusion</p> <p>Our <it>in vitro </it>studies showed that the two steroidal AIs, <b>3a </b>and <b>4a</b>, are potent inhibitors of breast cancer cell proliferation. Moreover, it was also shown that the antiproliferative effects of these two steroids on MCF-7aro cells are mediated by disrupting cell cycle progression, through cell cycle arrest in G<sub>0</sub>/G<sub>1 </sub>phase and induction of cell death, being the dominant mechanism autophagic cell death. Our results are important for the elucidation of the cellular effects of steroidal AIs on breast cancer.</p
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