7,790 research outputs found

    Long slit spectroscopy of a sample of isolated spirals with and without an AGN

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    We present the kinematical data obtained for a sample of active (Seyfert) and non active isolated spiral galaxies, based on long slit spectra along several position angles in the Halpha line region and, in some cases, in the Ca triplet region as well. Gas velocity distributions are presented, together with a simple circular rotation model that allows to determine the kinematical major axes. Stellar velocity distributions are also shown. The main result is that active and control galaxies seem to be equivalent in all kinematical aspects. For both subsamples, the departure from pure circular rotation in some galaxies can be explained by the presence of a bar and/or of a spiral arm. They also present the same kind of peculiarities, in particular, S-shape structures are quite common near the nuclear regions. They define very similar Tully-Fisher relations. Emission line ratios are given for all the detected HII regions; the analysis of the [NII]/Halpha metallicity indicator shows that active and non-active galaxies have indistinguishable disk metallicities. These results argue in favour of active and non-active isolated spiral galaxies having essentially the same properties, in agreement with our previous results based on the analysis of near infrared images. It appears now necessary to confirm these results on a larger sample.Comment: 35 pages, 54 figures, Accepted for publication in Astronomy & Astrophysics The full paper with its figures is available on the anonymous account of ftp.iap.fr in /home/ftp/pub/from_users/durret/marquez.ps.gz (999 kb

    Density estimates on a parabolic spde

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    We consider a general class of parabolic spde's [formula] with (t, x) [member of] [0, T]×[0, 1] and [epsilon]Wt,x, [epsilon] > 0, a perturbed Gaussian space-time white noise. For (t, x) [member of] (0, T]×(0, 1) we prove the called Davies and Varadhan-Léandre estimates of the density p[epsilon]t,x of the solution u[epsilon]t,x

    Classical properties of algebras using a new graph association

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    We study the relation between algebraic structures and Graph Theory. We have defined five different weighted digraphs associated to a finite dimensional algebra over a field in order to tackle important properties of the associated algebras, mainly the nilpotency and solvability in the case of Leibniz algebras

    Computing coset leaders and leader codewords of binary codes

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    In this paper we use the Gr\"obner representation of a binary linear code C\mathcal C to give efficient algorithms for computing the whole set of coset leaders, denoted by CL(C)\mathrm{CL}(\mathcal C) and the set of leader codewords, denoted by L(C)\mathrm L(\mathcal C). The first algorithm could be adapted to provide not only the Newton and the covering radius of C\mathcal C but also to determine the coset leader weight distribution. Moreover, providing the set of leader codewords we have a test-set for decoding by a gradient-like decoding algorithm. Another contribution of this article is the relation stablished between zero neighbours and leader codewords

    Introduzione alla biopolitica. Dodici voci fondamentali.

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    Identidad sexual y Derecho. Estudio interdisciplinario del transexualismo. [Reseña]

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    Reseña de: Marina CAMPS MERLO, Identidad sexual y Derecho. Estudio interdisciplinario del transexualismo, Eunsa, Pamplona, 2007, 535 pp

    A new battery-charging method suggested by molecular dynamics simulations

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    Based on large-scale molecular dynamics simulations, we propose a new charging method that should be capable of charging a Lithium-ion battery in a fraction of the time needed when using traditional methods. This charging method uses an additional applied oscillatory electric field. Our simulation results show that this charging method offers a great reduction in the average intercalation time for Li+ ions, which dominates the charging time. The oscillating field not only increases the diffusion rate of Li+ ions in the electrolyte but, more importantly, also enhances intercalation by lowering the corresponding overall energy barrier.Comment: 11 pages, 5 figure

    Educational Development Units in Spain: Current status and emerging trends

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    Recent studies show that the character, function and goals of Educational Development Units (EDUs) in many countries are undergoing a shift, and they now tend to support universities and learning in a more comprehensive way. The status of Spanish EDUs, however, has not been studied in detail. The aim of this article is to describe the current status of 45 such units to explore the degree to which a similar shift can be observed. The data revealed clusters, from which four models were defined. The models illustrate the increasing diversity of functions and widening scope of practice within Spanish EDUs

    Solving Sudoku with Membrane Computing

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    Sudoku is a very popular puzzle which consists on placing several numbers in a squared grid according to some simple rules. In this paper we present an efficient family of P systems which solve sudokus of any order verifying a specific property. The solution is searched by using a simple human-style method. If the sudoku cannot be solved by using this strategy, the P system detects this drawback and then the computations stops and returns No. Otherwise, the P system encodes the solution and returns Yes in the last computation step.Ministerio de Ciencia e Innovación TIN2008-04487-EMinisterio de Ciencia e Innovación TIN2009–13192Junta de Andalucía P08-TIC-0420
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