10,409 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"\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

    Determinação do equivalente de salinidade de sais substitutos do cloreto de sódio.

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

    Sal: de salvador a inimigo público.

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

    Mirar. Espaço de formação permanente de professores educadores ambientais : que espaço é esse?

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    Apresenta-se uma pesquisa-ação em andamento que busca compreender a formação continuada de um grupo de professores. Questiona-se se o processo de formação continuada do grupo contribui para a constituição de uma comunidade aprendente de professores educadores ambientais em um enfoque estético. A proposta formativa em 2008 foi na escrita narrativa como modo de configuração da realidade mediante o desenvolvimento e aplicação de Unidades de Aprendizagem (UA) numa abordagem que relaciona Ciência, Tecnologia e Sociedade. Os dados para a investigação foram coletados durante as reuniões semanais do grupo e nos registros de desenvolvimento e aplicação das UAs na educação básica postados em um ambiente virtual de aprendizagem. Os resultados preliminares mostram um movimento intenso de formação em alguns professores, estagnação em outros e até mesmo retrocesso de poucos

    Strong evidences for a nonextensive behavior of the rotation period in Open Clusters

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    Time-dependent nonextensivity in a stellar astrophysical scenario combines nonextensive entropic indices qKq_{K} derived from the modified Kawaler's parametrization, and qq, obtained from rotational velocity distribution. These qq's are related through a heuristic single relation given by qq0(1Δt/qK)q\approx q_{0}(1-\Delta t/q_{K}), where tt is the cluster age. In a nonextensive scenario, these indices are quantities that measure the degree of nonextensivity present in the system. Recent studies reveal that the index qq is correlated to the formation rate of high-energy tails present in the distribution of rotation velocity. On the other hand, the index qKq_{K} is determined by the stellar rotation-age relationship. This depends on the magnetic field configuration through the expression qK=1+4aN/3q_{K}=1+4aN/3, where aa and NN denote the saturation level of the star magnetic field and its topology, respectively. In the present study, we show that the connection qqKq-q_{K} is also consistent with 548 rotation period data for single main-sequence stars in 11 Open Clusters aged less than 1 Gyr. The value of qKq_{K}\sim 2.5 from our unsaturated model shows that the mean magnetic field topology of these stars is slightly more complex than a purely radial field. Our results also suggest that stellar rotational braking behavior affects the degree of anti-correlation between qq and cluster age tt. Finally, we suggest that stellar magnetic braking can be scaled by the entropic index qq.Comment: 6 pages and 2 figures, accepted to EPL on October 17, 201

    A nonextensive insight to the stellar initial mass function

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    the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by qq-Weibulls that emerge within nonextensive statistical mechanics. As a result, we show that the Salpeter's slope of \sim2.35 is replaced when a qq-Weibull distribution is used. Our results point out that the nonextensive entropic index qq represents a new approach for understanding the process of the star-forming and evolution of massive stars.Comment: 5 pages, 2 figures, Accepted to EP
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