Aquecimento ambiente com aquecedores eléctricos com e sem acumulação de calor

A manutenção das condições de conforto térmico no interior de muitos dos edifícios residenciais e de serviços durante os meses mais frios é conseguida com recurso a sistemas de aquecimento mais ou menos sofisticados que utilizam quantidades assinaláveis de energia. Para além das condições de conforto térmico é também importante assegurar a manutenção da qualidade do ar. Esta é conseguida em muitos casos com a utilização duma quantidade mínima de ar novo que terá também de ser aquecida

A utilização de sistemas solares térmicos nas unidades hoteleiras de 3 estrelas do Algarve

A região do Algarve é uma das regiões da União Europeia com maior potencialidade no aproveitamento da energia solar nomeadamente através da utilização de sistemas solares térmicos para aquecimento de água. A tecnologia utilizada nestes sistemas é relativamente simples e bem conhecida mas infelizmente verifica-se que, por diversas razões, nem sempre é aplicada. A alternativa, é a utilização de sistemas de aquecimento de água que utilizam combustíveis fósseis, quer de forma directa, como por exemplo através da queima de um combustível (gasóleo, gás propano, etc), ou de forma indirecta, através da electricidade. A utilização de combustíveis fósseis esta na origem de um dos maiores problemas ambientais da nossa época, o aquecimento global. Além disso, dependendo do tipo de combustível e d

Cytoskeletal scaffolds in neuronal development

Neuronal polarization is one of the most studied topics in neuroscience. In less than seven days neurites sprout out from the neuron, explore the surrounding environment and mature in axon or dendrites. This process is possible because the neuronal cytoskeleton can rapidly modify its architecture changing neuronal shape and length. Among all, two main proteins are involved: tubulin that supports the neurite elongation and builds a solid frame, while actin supports pathfinding. In this period of important cytoskeletal changes, it is possible to observe the actin waves (AW) that are highly dynamic structures emerging at the neurite base which move up to its tip, causing a transient retraction of the growth cone (GC). Since their discovery in 1988, there have been only few studies about AWs, usually linked to the neurite outgrowth and axon elongation. In the present work, I used long term live cell imaging to investigate alternative roles of such cytoskeletal phenomena. I examined in details AWs and I concluded that they do not promote the neurite outgrowth and that neurites can elongate for hundreds of microns without the AWs. Super resolution nanoscopy indicates that myosin II shapes the GC like AWs structure. The highly concentrated myosin inside the wave can bend the tubulin that support the neurite provoking twists and kinks in the microtubular cytoskeleton. These tubulin twists (TT) cause the GC retraction and are completely abolished with the inhibition of myosin II, that compromises the AW morphology. My results indicate that myosin II has an important role in the AWs dynamics and can bend the tubulin in a way that was not previously observed. Finally, we suggested a role for AWs and TTs in GC exploration and in neurite maturation. Part of these results have already been published in Frontiers in Cellular Neuroscience in the article: Actin waves do not boost neurite outgrowth in the early stages of neuron maturation. We have a second manuscript in preparation entitled \u201cTubulin twists drive Growth Cone retraction and promote tubulin mixed polarity\u201d

« Le guide » de Bilge Karasu

Dans son Guide, Bilge Karasu, économe comme un piège tendu, tend ses filets de conjectures entre quatre personnages, entre lesquels se nouent des relations très sérieuses en quelques jours. Son livre interroge le cheminement de l'existence dans la part qui touche à la source de nos rêves. Cela lui permet de donner toute la mesure de son vertige, car tout ce qu'on a pensé, prévu, rêvé à haute voix et dont on est persuadé, se produit vraiment ­ comme cela pourrait justement arriver dans un monde inversé ­ où notre connaissance du temps serait à rebours

« Le guide » de Bilge Karasu

Dans son Guide, Bilge Karasu, économe comme un piège tendu, tend ses filets de conjectures entre quatre personnages, entre lesquels se nouent des relations très sérieuses en quelques jours. Son livre interroge le cheminement de l'existence dans la part qui touche à la source de nos rêves. Cela lui permet de donner toute la mesure de son vertige, car tout ce qu'on a pensé, prévu, rêvé à haute voix et dont on est persuadé, se produit vraiment ­ comme cela pourrait justement arriver dans un monde inversé ­ où notre connaissance du temps serait à rebours

Un statut dans la République, une position dans la classe ouvrière : les travailleurs de l’État (1897-1951)

Les travailleurs de l’État des arsenaux de terre appartiennent comme les cheminots au monde des professions stratégiques. Peu grévistes en 1936, ils sont résistants 5 ans plus tard, et révoqués nombreux après guerre.Âprement défendu quand il est remis en cause, leur statut s’est substitué aux distinctions corporatives ; ce n’est pas une simple solidarité de métier malgré le rôle des écoles techniques dans la cohésion du personnel, ni un capital d’avantages, ni une simple conséquence du statut d’arsenal. C’est aussi une conscience de statut soutenue par un syndicalisme puissant.Il s’enracine par la retraite et la carrière au temps de la précarité, le salaire et la promotion dans la société de consommation. Mais sa légitimité est liée à la spécificité de la production des armes. Par suite, ce qui était une force tant que la guerre était le ciment des cités est une faiblesse quand elle en devient le remord et la crainte, que la globalisation anticipe le dépassement des frontières, que se diluent les espaces de souveraineté et de légitimité.Like railwaymen, State workers at land arsenals belong to a group of strategic professions. Less likely to strike than others in 1936, they joined the Resistance five years later were often dismissed after 1945.Bitterly defended when threatened, their regulations replaced their corporative rights; it was not a question of simple labour solidarity despite their common background at the same professional schools or of an acquired reserve of advantages, nor the simple consequence of having arsenal status. It was also an occupational awareness of regulations that was supported by union power.These regulations entrenched themselves through retirement and career plans in more precarious times, and through wages and promotions in the current consumer society. Their legitimacy is related to the specificity of the production of weapons. Consequently, what was perceived as strength as long as war led nations to join forces becomes a weakness when it corresponds to guilt and fear, when globalization erases borders, and when sovereignty and legitimacy are weakened. Résumé traduit du français par Kenneth Berr

Short-Sale Constraints and Corporate Investment

In a sample of non-U.S. regulatory regime shifts, we find that expanded short selling is associated with stock price declines, reductions in capital expenditure, and lower asset growth. In a reversal of results found for U.S. stocks in a study of Regulation SHO by Grullon, Michenaud, and Weston (2015), our results are stronger for large firms than for small firms. We also show that this investment effect is stronger for firms that previously relied on outside financing. Our results suggest that short-sale policies affect corporate investment and that this effect is not driven by capital constraints

A utilização de sistemas de cogeração e de sistemas frigoríficos de absorção nos hospitais portugueses

Dissertação de mestrado, Ciências Económicas e Empresariais, Unidade de Economia e Administração, Universidade do Algarve. Instituto Superiror de Economia e Gestão, Universidade Técnica de Lisboa, 1995O presente trabalho efectua a análise da situação energética dos hospitais distritais portugueses e estuda as vantagens da implementação dos sistemas de cogeração e dos sistemas frigoríficos de absorção. São analisados diferentes hospitais portugueses e é efectuada a caracterização de um hospital distrital tipo