The microlensing signatures of starspots

Point lens microlensing events with impact parameter close to the source stellar radius allow the observer to study the surface brightness profile of the lensed source. We have examined the effect of photospheric star spots on multicolour microlensing lightcurves and investigated the detectability of such spots in different wavebands as a function of spot temperature, position, radius and lens trajectories. We include the effect of limb darkening and spot projection as a function of position on the stellar disc. In particular we apply the updated, state-of-the-art NEXTGEN stellar atmosphere models of Hauschildt et al which predict very strong limb darkening and which are likely to be applicable to the source stars considered here. Our results indicate that star spots generally give a clear signature for transit events. Moreover, this signature is strongly suppressed by limb darkening for spots close to the limb, although the spots may still be clearly detected for favourable lens trajectories. It is also clear that intensive temporal sampling throughout the duration of the transit is necessary in order for such events to be effective as a tool for imaging stellar photospheres. Nonetheless, with sufficiently well sampled light curves of good photometric precision, microlensing can indeed place useful constraints on the presence or otherwise of photospheric starspots.Comment: 12 pages, 10 figures, MNRAS 335, 539 (2002

Evolucion y perspectivas del sector vitivinicola

Peer Reviewe

O gerenciamento dos documentos do sistema da qualidade

Descreve conceitos básicos sobre a sistemática de documentação de processos de trabalho, a estruturação do controle documental e o seu gerenciamento, de acordo com as diretrizes ISO 9000. Os requisitos da série IS0 9000 relacionados ao tema, Controle de Documentos e de Dados e Controle de Registros da Qualidade são detalhados objetivando maior entendimento e contribuindo para a implantação de um controle documental focado em seus reais objetivos

O enfoque por processos da NBR ISO 9001 e sua aplicação nos serviços de informação

Este artigo tem como objetivo principal apresentar e discutir os fundamentos da gestão da qualidade e da nova versão da NBR ISO 9001, incluindo a aplicação do enfoque por processos nos serviços de informação, com o objetivo de apoiar a melhoria dos processos implantados nestes serviços e principalmente apoiar seu gerenciamento, visando à otimização de recursos e à elevação dos níveis de satisfação dos clientes, itens considerados fundamentais pelas organizações que optam por programas relacionados à gestão da qualidade. Palavras-chave ISO 9001; Serviços de informação; Gestão da qualidade. Approach by NBR ISO 9001 processes applied to information services Abstracts The main role of this paper is to present and discuss the principles of Quality Management and the new version of ISO 9001, including the application of processes of new approach to Information Services, intended to improve the processes established in these services and mainly to support its management, having in mind the resources of optimization and improvement of customers’ satisfaction, items considered as fundamental to the Organizations in charge of quality management related to programs. Keywords ISO 9001; Information services; Quality management

Metastability, Mode Coupling and the Glass Transition

Mode coupling theory (MCT) has been successful in explaining the observed sequence of time relaxations in dense fluids. Previous expositions of this theory showing this sequence have required the existence of an ideal glass transition temperature $T_0$. Recent experiments show no evidence of $T_0$. We show here how the theory can be reformulated, in a fundamental way, such that one retains this sequence of relaxation behaviors but with a smooth temperature dependence and without any indication of $T_0$. The key ingredient in the reformulation is the inclusion of the metastable nature of the glass transition problem through a coupling of the mass density to the defect density. A main result of our theory is that the exponents governing the sequence of time relaxations are weak functions of the temperature in contrast to the results from conventional MCT.Comment: 14 pages (2 figures upon request), REVTEX

Un puñal de la Edad del Bronce hallado en El Mirón, Avila.

89 Jan.-Dez. 1979, p. 327-331

O papel da gestão documental nos processos de gestão do conhecimento

A identificação da interface entre as atividades de gestão de documentos, da informação e do conhecimento, com o intuito de demonstrar o papel dos arquivos como auxiliares nos processos de criação e compartilhamento do conhecimento corporativo foram os elementos centrais desta pesquisa. Por meio de pesquisa bibliográfica, foi contextualizado o trabalho, onde primeiramente foram definidos os temas que permeiam as teorias que compõem a Gestão da Informação e do Conhecimento, seguido pelo estudo das práticas arquivísticas e da Gestão Documental. A partir desta fundamentação teórica, foram definidas similaridades entre as disciplinas e a forma como os arquivos podem contribuir na gestão do conhecimento e suas práticas. Deste modo, o resultado esperado com esta pesquisa é a produção de uma análise que identifique a área de arquivos e seus profissionais como parte importante nos processos de gestão do conhecimento, levando a organização a ser mais eficiente nas tomadas de decisões que garantem o desenvolvimento sustentável de suas operações

Periodic solutions of linear, Riccati, and Abel dynamic equations

We study the number of periodic solutions of linear, Riccati and Abel dynamic equations in the time scales setting. In this way, we recover known results for corresponding differential equations and obtain new results for associated difference equations. In particular, we prove that there is no upper bound for the number of isolated periodic solutions of Abel difference equations. One of the main tools introduced to get our results is a suitable Melnikov function. This is the first time that Melnikov functions are used for dynamic equations on time scales

Metastable Dynamics above the Glass Transition

The element of metastability is incorporated in the fluctuating nonlinear hydrodynamic description of the mode coupling theory (MCT) of the liquid-glass transition. This is achieved through the introduction of the defect density variable $n$ into the set of slow variables with the mass density $\rho$ and the momentum density ${\bf g}$. As a first approximation, we consider the case where motions associated with $n$ are much slower than those associated with $\rho$. Self-consistently, assuming one is near a critical surface in the MCT sense, we find that the observed slowing down of the dynamics corresponds to a certain limit of a very shallow metastable well and a weak coupling between $\rho$ and $n$. The metastability parameters as well as the exponents describing the observed sequence of time relaxations are given as smooth functions of the temperature without any evidence for a special temperature. We then investigate the case where the defect dynamics is included. We find that the slowing down of the dynamics corresponds to the system arranging itself such that the kinetic coefficient $\gamma_v$ governing the diffusion of the defects approaches from above a small temperature-dependent value $\gamma^c_v$.Comment: 38 pages, 14 figures (6 figs. are included as a uuencoded tar- compressed file. The rest is available upon request.), RevTEX3.0+eps

¿Cuál es la percepción del alumnado universitario sobre la influencia de las metodologías activas en el proceso de enseñanza-aprendizaje?

La utilización de metodologías activas que centran la enseñanza en el alumnado es respaldada actualmente por fomentar un proceso de enseñanza-aprendizaje constructivo. El objetivo de este trabajo fue analizar la percepción del estudiantado de educación superior sobre la influencia de las metodologías participativas y las metodologías tradicionales en el proceso de enseñanza-aprendizaje. La experiencia se realizó en alumnado del Grado en Maestra/o de Educación Primaria. Se implementó una metodología activa durante dos meses y una metodología tradicional durante los siguientes dos meses. Tras la intervención, el alumnado completó un cuestionario de valoración. Los resultados mostraron que un 81 % número de alumnado percibe que la metodología activa ayudó a mantener el interés y la motivación por la materia, así como el 78 % consideró que aumentó la participación y el 89 % que fomentó la colaboración en el aula de teoría en comparación con la metodología tradicional. Aunque al 79 % del alumnado le gustaría seguir utilizando las metodologías activas, el 75 % consideró que la combinación de ambas metodologías resulta de utilidad. En conclusión, las metodologías activas generan una mayor percepción positiva sobre el proceso de enseñanza-aprendizaje en educación superior. Sin embargo, las metodologías tradicionales no deben descartarse