7,806 research outputs found

    Nonextensivity in the solar magnetic activity during the increasing phase of solar Cycle 23

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    In this paper we analyze the behavior of the daily Sunspot Number from the Sunspot Index Data Center (SIDC), the mean Magnetic Field strength from the National Solar Observatory/Kitt Peak (NSO/KP) and Total Solar Irradiance means from Virgo/SoHO, in the context of the qq--Triplet which emerges within nonextensive statistical mechanics. Distributions for the mean solar Magnetic Field show two different behaviors, with a qq--Gaussian for scales of 1 to 16 days and a Gaussian for scales longer than 32 days. The latter corresponds to an equilibrium state. Distributions for Total Solar Irradiance also show two different behaviors (approximately Gaussian) for scales of 128 days and longer, consistent with statistical equilibrium and qq--Gaussian for scales << 128 days. Distributions for the Sunspot Number show a qq--Gaussian independent of timescales, consistent with a nonequilibrium state. The values obtained ("qq--Triplet"ā‰”\equiv{\{qqstat_{stat},qqsen_{sen},qqrel_{rel}}\}) demonstrate that the Gaussian or qq--Gaussian behavior of the aforementioned data depends significantly on timescales. These results point to strong multifractal behavior of the dataset analyzed, with the multifractal level decreasing from Sunspot Number to Total Solar Irradiance. In addition, we found a numerically satisfied dual relation between qstatq_{stat} and qsenq_{sen}.Comment: 6 pages, 4 figure

    DeterminaĆ§Ć£o do equivalente de salinidade de sais substitutos do cloreto de sĆ³dio.

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    bitstream/item/74486/1/pub-194.pd

    Sal: de salvador a inimigo pĆŗblico.

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    bitstream/item/28967/1/2010-296.pd

    Phase Transition and Monopoles Densities in a Nearest Neighbors Two-Dimensional Spin Ice Model

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    In this work, we show that, due to the alternating orientation of the spins in the ground state of the artificial square spin ice, the influence of a set of spins at a certain distance of a reference spin decreases faster than the expected result for the long range dipolar interaction, justifying the use of the nearest neighbor two dimensional square spin ice model as an effective model. Using an extension of the model presented in ref. [Scientific Reports 5, 15875 (2015)], considering the influence of the eight nearest neighbors of each spin on the lattice, we analyze the thermodynamics of the model and study the monopoles and string densities dependence as a function of the temperature.Comment: 11 pages, 8 figure

    Does e-learning policy drive change in Higher Education?: A case study relating models of organisational change to e-learning implementation

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    Due to the heightened competition introduced by the potential global market and the need for structural changes within organisations delivering e-content, e-learning policy is beginning to take on a more significant role within the context of educational policy per se. For this reason, it is becoming increasingly important to establish what effect such policies have and how they are achieved. This paper addresses this question, illustrating five ways in which change is understood (Fordist, evolutionary, ecological, community of practice and discourse-oriented) and then using this range of perspectives to explore how e-learning policy drives change (both organisational and pedagogic) within a selected higher education institution. The implications of this case are then discussed, and both methodological and pragmatic conclusions are drawn, considering the relative insights offered by the models and ways in which change around e-learning might be supported or promoted

    Mirar. EspaƧo de formaĆ§Ć£o permanente de professores educadores ambientais : que espaƧo Ć© esse?

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    Apresenta-se uma pesquisa-aĆ§Ć£o em andamento que busca compreender a formaĆ§Ć£o continuada de um grupo de professores. Questiona-se se o processo de formaĆ§Ć£o continuada do grupo contribui para a constituiĆ§Ć£o de uma comunidade aprendente de professores educadores ambientais em um enfoque estĆ©tico. A proposta formativa em 2008 foi na escrita narrativa como modo de configuraĆ§Ć£o da realidade mediante o desenvolvimento e aplicaĆ§Ć£o de Unidades de Aprendizagem (UA) numa abordagem que relaciona CiĆŖncia, Tecnologia e Sociedade. Os dados para a investigaĆ§Ć£o foram coletados durante as reuniƵes semanais do grupo e nos registros de desenvolvimento e aplicaĆ§Ć£o das UAs na educaĆ§Ć£o bĆ”sica postados em um ambiente virtual de aprendizagem. Os resultados preliminares mostram um movimento intenso de formaĆ§Ć£o em alguns professores, estagnaĆ§Ć£o em outros e atĆ© mesmo retrocesso de poucos
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