7,790 research outputs found
Long slit spectroscopy of a sample of isolated spirals with and without an AGN
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
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
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
In this paper we use the Gr\"obner representation of a binary linear code
to give efficient algorithms for computing the whole set of coset
leaders, denoted by and the set of leader codewords,
denoted by . The first algorithm could be adapted to
provide not only the Newton and the covering radius of 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
Identidad sexual y Derecho. Estudio interdisciplinario del transexualismo. [Reseña]
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
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
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
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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