15,068 research outputs found

    Asteroseismic Theory of Rapidly Oscillating Ap Stars

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    This paper reviews some of the important advances made over the last decade concerning theory of roAp stars.Comment: 9 pages, 5 figure

    Accessing the Acceleration of the Universe with Sunyaev-Zel'dovich and X-ray Data from Galaxy Clusters

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    By using exclusively the Sunyaev-Zel'dovich effect and X-ray surface brightness data from 25 galaxy clusters in the redshift range 0.023< z < 0.784 we access cosmic acceleration employing a kinematic description. Such result is fully independent on the validity of any metric gravity theory, the possible matter-energy contents filling the Universe, as well as on the SNe Ia Hubble diagram.Comment: 3 pages, 4 figures, To appear in the Proceedings of the Twelfth Marcel Grossmann Meeting on General Relativit

    Are Galaxy Clusters Suggesting an Accelerating Universe?

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    The present cosmic accelerating stage is discussed through a new kinematic method based on the Sunyaev- Zel'dovich effect (SZE) and X-ray surface brightness data from galaxy clusters. By using the SZE/X-ray data from 38 galaxy clusters in the redshift range 0.14z0.890.14 \leq z \leq 0.89 [Bonamente et al., Astrop. J. {\bf 647}, 25 (2006)] it is found that the present Universe is accelerating and that the transition from an earlier decelerating to a late time accelerating regime is relatively recent. The ability of the ongoing Planck satellite mission to obtain tighter constraints on the expansion history through SZE/X-ray angular diameters is also discussed. Our results are fully independent on the validity of any metric gravity theory, the possible matter- energy contents filling the Universe, as well as on the SNe Ia Hubble diagram from which the presenting accelerating stage was inferred.Comment: 6 pages, 6 figures, AIP Conf. Proc. Invisible Universe: Proceedings of the Conferenc

    Web semântica: estudo preliminar.

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    Web x Web semântica. Representação do conhecimento. Ontologia. Agentes inteligentes. Metadados. Arquitetura de descrição de recursos. Tipos de linguagens a para construção da Web semãntica.bitstream/CNPTIA/9942/1/doc18.pdfAcesso em: 29 maio 2008

    Topological mass generation to antisymmetric tensor matter field

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    We propose a mechanism to give mass to tensor matter field which preserve the U(1) symmetry. We introduce a complex vector field that couples with the tensor in a topological term. We also analyze the influence of the kinetic terms of the complex vector in our mechanism.Comment: 5 pages, to appear in Europhysics Letter

    Refactoring smelly spreadsheet models

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    Identifying bad design patterns in software is a successful and inspiring research trend. While these patterns do not necessarily correspond to software errors, the fact is that they raise potential problematic issues, often referred to as code smells, and that can for example compromise maintainability or evolution. The identification of code smells in spreadsheets, which can be viewed as software development environments for non-professional programmers, has already been the subject of confluent researches by different groups. While these research groups have focused on detecting smells on concrete spreadsheets, or spreadsheet instances, in this paper we propose a comprehensive set of smells for abstract representations of spreadsheets, or spreadsheet models. We also propose a set of refactorings suggesting how spreadsheet models can become simpler to understand, manipulate and evolve. Finally we present the integration of both smells and refactorings under the MDSheet framework.Part funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT - Fundação para a Ciência e a Tecnologia within projects FCOMP-01-0124-FEDER-022701 and Network Sensing for Critical Systems Monitoring (NORTE-01-0124-FEDER-000058), ref. BIM-2013 BestCase RL3.2 UMINHO
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