1,080 research outputs found
On the nature of some SGRs and AXPs as rotation-powered neutron stars
We investigate the possibility that some SGRs/AXPs could be canonical
rotation-powered pulsars using realistic NS structure parameters instead of
fiducial values. We show that realistic NS parameters lowers the estimated
value of the magnetic field and radiation efficiency, ,
with respect to estimates based on fiducial NS parameters. We show that nine
SGRs/AXPs can be described as canonical pulsars driven by the NS rotational
energy, for computed in the soft (2--10~keV) X-ray band. We compute the
range of NS masses for which . We discuss the observed
hard X-ray emission in three sources of the group of nine potentially
rotation-powered NSs. This additional hard X-ray component dominates over the
soft one leading to in two of them. We show that 9
SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in
the soft 2--10~keV band. Interestingly, four of them show radio emission and
six have been associated with supernova remnants (including Swift J1834.9-0846
the first SGR observed with a surrounding wind nebula). These observations give
additional support to our results of a natural explanation of these sources in
terms of ordinary pulsars. Including the hard X-ray emission observed in three
sources of the group of potential rotation-powered NSs, this number of sources
with becomes seven. It remains open to verification
1) the accuracy of the estimated distances and 2) the possible contribution of
the associated supernova remnants to the hard X-ray emission.Comment: 11 pages, 14 figures, to appear in A&
Una aproximación sintaxonómica sobre la vegetación del Perú: clases, órdenes y alianzas
Una aproximación sintaxonómica sobre la vegetación del Perú. Clases, órdenes y alianzas. En el presente trabajo damos a conocer una primera aproximación al esquema sintaxonómico de la vegetación peruana hasta el nivel de alianza. Se describen dos nuevas clases (Nicotiano-Ambrosietea y Mayacetea fluviatilis), 12 órdenes (Adiantetalia raddiani, Alnetalia, Cestro-Prunetalia, Commelinetalia, Cryptocarpo-Prosopidetalia, Mutisio-Baccharidetalia, Nicotianetalia, Oryzo-Hymenachnetalia, Polylepidetalia racemosae, Polypodio-Puyetalia, Salicetalia caroliniano-humboldtianae y Saxifragetalia magellanicae), 14 alianzas (Adiantion subvolubilis, Aristido-Chloridion, Bursero-Prosopidion, Espostoo-Neoraimondion, Loasion, Mutisio-Ophryosporidion, Myrcianthion quinquelobae, Myrico-Alnion, Peperomio-Puyion, Ribesido-Polylepidion, Saxifragion magellanicae, Sicyo-Urticion, Siegesbeckio-Commelinion y Tecomion arequipensis) y 10 asociaciones (Adiantetum subvolubilis, Barnadesio-Ophryosporidetum, Cercidio-Prosopidetum, Haageocereo-Neoraimondietum, Peperomio-Tillandsietum, Philoglosso-Urocarpidetum, Schino-Acacietum, Tristerido-Myrcianthetum, Valeriano-Saxifragetum y Valleo-Alnetum). Además se establece un estado nuevo (Chusqueetalia tessellatae stat. nov.) que permite sistematizar los matorrales andinos con bambusoideas ("chuscales")
Infraestructura de datos espaciales en medio ambiente y acceso a la información ambiental en Andalucía. El canal de la red de información ambiental de Andalucía.
La Consejería de Medio Ambiente de la Junta de Andalucía ha puesto en marcha un sistema para poder cumplir adecuadamente los requisitos derivados de la normativa vigente en dos vertientes que están muy relacionadas: la del acceso a la información ambiental y la de las Infraestructuras de Datos Espaciales. Ambas vertientes, que vienen definidas por sendas Directivas, han condicionado la solución establecida que pasa por la creación mediante el desarrollo normativo adecuado de un instrumento, la Red de Información Ambiental de Andalucía (REDIAM). Esta red se ha dotado de una plataforma en entorno web, el Canal de la Red de Información Ambiental de Andalucía, en la que confluyen elementos constitutivos de una Infraestructura de Datos Espaciales (IDE) con otros de obtención y acceso al dato como es el de de solicitud de información ambiental o la descarga directa, y con elementos de navegación que pretenden facilitar al público en general el acceso a este conjunto de servicios y productos. Puesto en explotación el 29 de enero de 2009, hoy podemos hacer balance del uso que ha registrado en su primer año.The Ministry of Environment of the Junta de Andalucía has launched a system to carry out the requirements under current regulations in two areas which are closely related: access to environmental information and Spatial Data Infrastructures. Both sides, which are defined by EU Directives, have conditioned the solution through the developing an appropriate regulatory instrument, the Environmental Information Network of Andalusia (REDIAM). This network has set up a web-based platform, the Andalusian Environmental Information Network Channel, which combines elements of a Spatial Data Infrastructure (SDI) with other elements of data collection and access like the environmental information request or direct download, and navigation elements that are intended to facilitate the general public access to the package of services and products. Having been put into operation on January 29, 2009, today we can assess the use it has registered in its first year
Mapa guía digital del espacio natural de Doñana: un sistema de difusión y acceso a la información técnica de la Rediam
Dentro de la línea de difusión de información ambiental que imponen directrices europeas, leyes estatales y
autonómicas, se ha planteado dar un giro a la clásica producción de los mapas guía de los espacios naturales de
Andalucía. Esta nació con el Mapa Guía de Doñana en el año 1989 y ha venido y viene renovándose desde entonces
con nuevas versiones.
A lo largo de este tiempo, la tecnología y la información disponible han cambiado notablemente, y con objeto de
facilitar a los ciudadanos el manejo de la información cartográfica existente de los diferentes Espacios Naturales, se
crea un nuevo concepto denominado “Mapas Guía Digitales de Espacios Naturales”.
El mapa guía digital de Doñana, se presenta como una amplia guía en formato “libro-disco”, aunando la
proximidad de un texto amenizado con fotografías, con una potente herramienta informática que facilita análisis
cartográficos, o recorridos virtuales.
El texto permite conocer Doñana desde la perspectiva ambiental, y la aplicación informática, a una completa
información sobre vegetación, equipamientos, ecosistemas, historia y tradiciones, además de imágenes satélite,
ortofotos y fotografías. Por su especial relevancia, la AVIFAUNA ha sido tratada de forma especial integrando en la
aplicación una completa guía de campo.In-line dissemination of environmental information that impose European guidelines, state and regional, has been
raised to turn the classic guide to production of maps of natural areas of Andalusia.This was created with the Map
Guide Doñana in 1989 and has been renewed and comes with new versions since then.
Throughout this time, technology and information available have changed dramatically, and in order to provide
citizens with the management of topographic data available from different natural areas, establishing a new concept
called "Digital Guide Maps of Natural Spaces”.
The digital guide map of Doñana, is presented as a comprehensive guide format "book-album", combining the
proximity of a text enlivened with photographs, with a powerful analysis tool that facilitates mapping or virtual tours. The text allows Doñana know from an environmental perspective, and computer application, to complete
information about vegetation, equipment, ecosystems, history and traditions, in addition to satellite imagery,
orthophotos and photographs. Because of its special relevance, BIRDS has been specially treated in the
implementation integrating a complete field guide
The Period-Luminosity Relation of RR Lyrae Stars in the SDSS Photometric System
We provide the first detailed study of the RR Lyrae period-luminosity (PL)
relation in the ugriz bandpasses of the Sloan Digital Sky Survey (SDSS) filter
system. We argue that tight, simple PL relations are not present in the SDSS
filters, except for the redder bandpasses i and (especially) z. However, for
all bandpasses, we show that, by incorporating terms involving a (fairly
reddening-independent) "pseudo-color" C_0 = (u-g)_0 - (g-r)_0, tight
(non-linear) relations do obtain. We provide theoretically calibrated such
relations in the present paper, which should be useful to derive precise
absolute magnitudes (hence distances) and intrinsic colors (hence reddening
values) to even {\em individual} field RR Lyrae stars. For applications to
cases where photometry in all five passbands may not be available, we also
provide simple (though less precise) average PL relations for the i and z
bandpasses, which read as follows:
M_z = 0.839 - 1.295 log P + 0.211 log Z,
M_i = 0.908 - 1.035 log P + 0.220 log Z.
Similarly, simple period-color relations for (r-i)_0, (g-r)_0, and (u-z)_0
are also provided.Comment: 7 pages, 9 figures. ApJS, in pres
Una aproximación sintaxonómica sobre la vegetación del Perú. Clases, órdenes y alianzas
RESUMEN. Una aproximación sintaxonómica sobre la vegetación del Perú. Clases, órdenes y alianzas. En el presente trabajo damos a conocer una primera aproximación al esquema sintaxonómico de la vegetación peruana hasta el nivel de alianza. Se describen dos nuevas clases (Nicotiano- Ambrosietea y Mayaceteaf luviatilis), 12 órdenes (Adiantetalia raddiani, Alnetalia, Cestro-Prunetalia, Commelinetalia, Cryptocarpo-Prosopidetalia, Mutisio-Baccharidetalia, Nicotianetalia, Oryzo- Hymenachnetalia, Polylepidetalia racemosae, Polypodio-Puyetalia, Salicetalia caroliniano- humbolchianae ySaxifragetalia magellanicae), 14 alianzas (Adiantion subvolubilis, Aristido-Chloridion, Bursero-Prosopidion, Espostoo-Neoraimondion, Loasion, Mutisio-Ophryosporidion, Myrcianthion quinquelobae, Myrico-Alnion, Peperomio-Puyion, Ribesido-Polylepidion, Saxifragion magellanicae, Sicyo-Urficion„Siegesbeckio-Commelinion y Tecomion arequipensis) y 10 asociaciones (Adiantetum subvolubilis, Bartiadesio-Ophryosporidetum, Cercidio-Prosopidetum, Haageocereo-Neoraimondietum, Peperomio-Tillculdsietum, Philoglosso-Uroccopidetum,Schino-Acacietum,Tristerido-Myrcianthetum, Valeriano-Saxifragetum y Valleo-Alnetutn). Además se establece un estado nuevo (Chusqueetalia tessellatae stat.nov.)que permite sistematizar los matorrales andinos con bambusoideas ("chuscales").Palabras clave. Vegetación, Fitosociología, Sintaxonomfa, Perú.ABSTRACT. A syntaxonomic approximation about the vegetation of Peru. Classes, orders and alliances. In this paper, a first syntaxonomic approximation to the syntaxonomic scheme of the Peruvian vegetation down to the alliance level is presented. Two new classes (Nicoticmo-Ambrosietea and Mayacetea f hiviatilis), 12 orders (Adiantetalia raddiani, Alnetalia, Cestro-Prunetalia, Commelinetalia, Cryptocarpo-Prosopidetalia, Mutisio-Baccharidetalia, Nicotianetalia, Oryzo- Hymenachnetalia, Polylepidetalia racemosae, Polypodio-Puyetalia, Salicetalia caroliniano- humboldnanae and Saxifragetalia magellanicae), 14 alliances (Adicional subvolubilis, Aristido- Chloridion, Bursero-Prosopidion, Espostoo-Neoraimondion, Loasion, Munsio-Ophryosporidion, Myrciamhion quinquelobae, Myrico-Alnion, Peperomio-Puyion, Ribesido-Polylepidion, Saxifragion magellanicae, Sicyo-Urticion„Siegesbeckio-Commelinion and Tecomion arequipensis) and 10 associations (Adiametum subvolubilis, Bartiadesio-Ophryosporidetum, Cercidio-Prosopidetum, Haageocereo-Neoraimondietum, Peperomio-Tillandsiencm, Philoglosso-Urocarpidetutn, Schino- Acacietum, Tristerido-Myrcianthetum, Valeriano-Saxifragetunt and Valleo-Alnetum) are described. Also, a new status is stablished (Chusqueetalia tessellatae stat. nov. ) to systematize the Andean bamboo-scrubs ("chuscales").Key words. Vegetation, Phytosociology, Syntaxonomy, Peru
Real-time static potential in hot QCD
We derive a static potential for a heavy quark-antiquark pair propagating in
Minkowski time at finite temperature, by defining a suitable gauge-invariant
Green's function and computing it to first non-trivial order in Hard Thermal
Loop resummed perturbation theory. The resulting Debye-screened potential could
be used in models that attempt to describe the ``melting'' of heavy quarkonium
at high temperatures. We show, in particular, that the potential develops an
imaginary part, implying that thermal effects generate a finite width for the
quarkonium peak in the dilepton production rate. For quarkonium with a very
heavy constituent mass M, the width can be ignored for T \lsim g^2 M/12\pi,
where g^2 is the strong gauge coupling; for a physical case like bottomonium,
it could become important at temperatures as low as 250 MeV. Finally, we point
out that the physics related to the finite width originates from the
Landau-damping of low-frequency gauge fields, and could be studied
non-perturbatively by making use of the classical approximation.Comment: 20 pages. v2: a number of clarifications and a few references added;
published versio
SIOSE Andalucía, experiencia de integración y actualización de bases cartográficas multiescala
El objetivo de SIOSE en Andalucía ha sido la obtención de una base cartográfica de referencia a escala de detalle
1:10.000, escalable a 1:25.000, donde se sintetizan e integran tanto la información geométrica como la temática de
cartografías ya existentes (usos del territorio, SIGPAC, coberturas del suelo, información de comunidades fitosociológicas,
redes de comunicación, superficies húmedas, red hidrográfica, zonas de extracción, balsas, entramado urbano,
etc.) siguiendo un protocolo establecido para, posteriormente, actualizarla al año de referencia mediante fotointerpretación.
La integración de las diferentes cartografías se fundamentó en la definición de unos valores mínimos de
tolerancia, tanto de distancia entre líneas como de tamaño mínimo de superficie en función del uso asignado al polígono.
La generación de la cartografía a escala 1:25.000 se llevó a cabo a través de procesos automáticos de cambio
de modelo de datos, cambio de escala y eliminación de pasillos.
La inquietud de abordar la experiencia de SIOSE-Andalucía nace de la necesidad detectada desde hace tiempo de
tener una base de referencia que combine parámetros bióticos con elementos administrativos y el parcelario de la
propiedad.The aim of SIOSE in Andalucía has been obtaining a detailed scale 1:10.000 cartographic database of reference,
scalable to 1:25.000, where geometry and also thematic information of existing cartographies have been combined
and joined (land uses, SIGPAC, land covers, phytosociological plant communities, communication network, humid
areas, hydrographic network, extraction zones, irrigation pools, urban network, etc.) following an established protocol
for, afterwards, updating the cartography to the referred year using photo-interpretation. The integration of different
cartographies is based on the definition of minimum values of tolerance for the distance between lines as well as
minimum sizes of area, depending on the assigned land use to each polygon. The production of cartography
1:25.000 was carried out through automatic processes of data model converter, scale change and elimination of
narrowing polygons. The interest of tackling the experience of SIOSE-Andalucia is sprung from the detected necessity of having a resource
which combines biotic parameters with administrative elements and property divisions
Ordering and finite-size effects in the dynamics of one-dimensional transient patterns
We introduce and analyze a general one-dimensional model for the description
of transient patterns which occur in the evolution between two spatially
homogeneous states. This phenomenon occurs, for example, during the
Freedericksz transition in nematic liquid crystals.The dynamics leads to the
emergence of finite domains which are locally periodic and independent of each
other. This picture is substantiated by a finite-size scaling law for the
structure factor. The mechanism of evolution towards the final homogeneous
state is by local roll destruction and associated reduction of local
wavenumber. The scaling law breaks down for systems of size comparable to the
size of the locally periodic domains. For systems of this size or smaller, an
apparent nonlinear selection of a global wavelength holds, giving rise to long
lived periodic configurations which do not occur for large systems. We also
make explicit the unsuitability of a description of transient pattern dynamics
in terms of a few Fourier mode amplitudes, even for small systems with a few
linearly unstable modes.Comment: 18 pages (REVTEX) + 10 postscript figures appende
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