Entropy from the foam II

A simple model of spacetime foam, made by two different types of wormholes in a semiclassical approximation, is taken under examination: one type is a collection of $N_{w}$ Schwarzschild wormholes, while the other one is made by Schwarzschild-Anti-de Sitter wormholes. The area quantization related to the entropy via the Bekenstein-Hawking formula hints a possible selection between the two configurations. Application to the charged black hole are discussed.Comment: Revtex 3.0, 10 pages, Replaced version with minor changes and one ref. adde

The Quantum Stress-Tensor in Self-Similar Spherical Dust Collapse

We calculate the quantum stress tensor for a massless scalar field in the 2-d self-similar spherical dust collapse model which admits a naked singularity. We find that the outgoing radiation flux diverges on the Cauchy horizon. This may have two consequences. The resultant back reaction may prevent the naked singularity from forming, thus preserving cosmic censorship through quantum effects. The divergent flux may lead to an observable signature differentiating naked singularities from black holes in astrophysical observations.Comment: Latex File, 19 page

Quantum general relativity and Hawking radiation

In a previous paper we have set up the Wheeler-DeWitt equation which describes the quantum general relativistic collapse of a spherical dust cloud. In the present paper we specialize this equation to the case of matter perturbations around a black hole, and show that in the WKB approximation, the wave-functional describes an eternal black hole in equilibrium with a thermal bath at Hawking temperature.Comment: 13 pages, minor revisions in: (i) para 5 of Introduction, (ii) para following Eqn. (10). Revised version to appear in Phys. Rev.

Innovation public policy—the case of Portugal

Innovation public policy has an essential role in influencing the competitive capacity of companies and is strongly asso-ciated with their ability to innovate and the way they are organized. As important as the technological organization of work is the social dimension, namely, involvement, participation, and commitment of the workforce, as these are, par excellence, factors that contribute to creating added value and differentiation for companies. In this sense, the concept of innovation depends on an integrated vision between the human dimension and the other multiple dimensions that innovation can assume. Public policies, besides the goal of creating a more modern and competitive business and industrial context, also are focused on the development of the workforce, not only in digital competences but also in soft skills. This type of skill contributes to creating a more innovative context and a culture of innovation. This article’s goal is to make a global overview of innovation and the public policies to promote the modernization of companies and influence the way they contribute to economic growth.info:eu-repo/semantics/publishedVersio

Técnicas laboratoriais para isolamento de Campylobacter em material avícola.

Projeto/Plano de Ação: 03.08.06.004

On the error of calculation of heat gains through walls by methods using constant decrement factor and time lag values

A transient heat transfer model was developed to numerically predict the thermal behaviour of the external walls of a room under realistic outdoor conditions. The excitation is not simply sinusoidal even though it is considered to have daily periodicity. The numerical model is based on the finite difference method and handles one-dimensional heat conduction through multilayered walls. The boundary condition at the outer surface of the wall is described with the sol-air temperature concept. The temperatures of indoor air and of other internal surfaces in the room are assumed to be equal and constant. The numerical results were used to calculate values of the decrement factor and time lag of several walls. The calculation followed two methods found in literature, in which these parameters are assumed constant, distinguished by the temperature evolution used: the sol-air or the wall's outer surface. Additionally, the inner surface temperature is used in both methods. The walls investigated range from low to high mass construction, face towards various directions and have light or dark coloured sunlit outer surfaces. The heat fluxes at the inner surface of the walls predicted by numerical modelling and estimated by the simplified methods are compared in detail to conclude on the validity of these simplified methods. As a by-product it is also possible to conclude on the dependence of the decrement factor and of the time lag on the outer surface colour and on the orientation of different types of walls. The results show that both simplified methods have poor accuracy in a significant number of cases. Also, it was found that the wall's azimuth significantly affects the time lag

O cuidado nas profissões dedicadas ao bem-estar e desenvolvimento humano.

O livro O cuidado nas profissões dedicadas ao bem-estar e ao desenvolvimento humano” reúne contributos de académicos e profissionais de várias áreas disciplinares para pensar a relação do cuidado com os diversos campos de ação e da vida humana, nomeadamente o cuidado nas profissões dedicadas ao bem-estar e ao desenvolvimento humano, procurando ultrapassar os lugares comuns a ele ligados, bem como alguns estereótipos mais ou menos instalados sobre o tema. O livro emerge da vivência de um frutífero encontro que se deu nos dias 11 e 12 de novembro de 2016 na Universidade de Évora no colóquio “Cuidado: pare, escute, olhe e intervenha” sobre o cuidado nas profissões dedicadas ao bem-estar e ao desenvolvimento humano. Compõem esta publicação dezasseis textos organizados em três secções: na primeira - O Cuidado em diversas áreas de conhecimento - incluem-se três textos de fundo oriundos de três áreas do conhecimento em que o conceito de cuidado tem sido objeto de relevante atenção: “Prática e teoria do cuidado – polissemia de um conceito esquecido” pela Professora Irene Borges Duarte do Departamento de Filosofia da UE; “O ‘Cuidar’ na relação com o não hu¬mano: do Despotismo vs. Custódia às lições da Ecologia” pelo Professor João Ber¬nardo do Departamento de Paisagem, Ambiente e Ordenamento da UE e “Vulnerabilidade e sustentabilidade – uma equação difícil” pela Professora Manuela Silva do Instituto Superior de Economia e Gestão em que equaciona o nosso lugar e o nosso agir no mundo em que vivemos, perante desafios que nos enchem de perplexidade. Na segunda secção - O Cuidado na prática profissional – reúnem-se quatro testemunhos de profissionais (uma psicometrista uma psicóloga, uma educadora de infância, e duas enfermeiras) que nos falam de como integram na sua profissionalidade o ato de cuidar enquanto matriz fundamental da sua intervenção em prol do bem-estar e do desenvolvimento humano nas respetivas profissões. Na terceira e última secção do livro - O Cuidado em diálogo – incluem-se textos produzidos sobre e a partir das vivências no colóquio em que se incluem propostas de dinâmicas para pensar o cuidado nas profissões ligadas ao bem-estar e ao desenvolvimento humano e, ainda, quatro textos que espelham processos de reflexão sobre o conceito do cuidado vividos por autores, também eles de várias áreas profissionais e do conhecimento, a partir da experiência vivida no colóquio

Classical and quantum LTB model for the non-marginal case

We extend the classical and quantum treatment of the Lemaitre-Tolman-Bondi (LTB) model to the non-marginal case (defined by the fact that the shells of the dust cloud start with a non-vanishing velocity at infinity). We present the classical canonical formalism and address with particular care the boundary terms in the action. We give the general relation between dust time and Killing time. Employing a lattice regularization, we then derive and discuss for particular factor orderings exact solutions to all quantum constraints.Comment: 23 pages, no figures, typos correcte