246 research outputs found

    Cavidad de Stafne. Revisión a propósito de 6 casos

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    Presentamos un estudio de 6 casos de cavidades de Stafne, incluidas en una revisión que hemos realizado en 1536 casos de quistes de los maxilares. Existe una mayor incidencia en el sexo masculino (4:2) y en todos los casos el hallazgo fue casual. La sialograffa ha mostrado relación entre la cavidad y la glándula submaxilar. El tratamiento fue quirúrgico en cuatro casos y conservador en dos

    Hierarchical Star Formation: Stars and Stellar Clusters in the Gould Belt

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    We perform a study of the spatial and kinematical distribution of young open clusters in the solar neighborhood, discerning between bound clusters and transient stellar condensations within our sample. Then, we discriminate between Gould Belt (GB) and local Galactic disk (LGD) members, using a previous estimate of the structural parameters of both systems obtained from a sample of O-B6 Hipparcos stars. Using this classified sample we analyze the spatial structure and the kinematic behavior of the cluster system in the GB. The two star formation regions that dominate and give the GB its characteristic inclined shape show a striking difference in their content of star clusters: while Ori OB1 is richly populated by open clusters, not a single one can be found within the boundaries of Sco OB2. This is mirrored in the velocity space, translating again into an abundance of clusters in the region of the kinematic space populated by the members of Ori OB1, and a marginal number of them associated to Sco OB2. In the light of these results we study the nature of the GB with respect to the optical segment of the Orion Arm, and we propose that the different content of star clusters, the different heights over the Galactic plane and the different residual velocities of Ori OB1 and Sco OB2 can be explained in terms of their relative position to the density maximum of the Local Arm in the solar neighborhood. Although morphologically intriguing, the GB appears to be the result of our local and biased view of a larger star cluster complex in the Local Arm, that could be explained by the internal dynamics of the Galactic disk.Comment: 23 pages, including 12 figures. Accepted for publication in MNRA

    The ALHAMBRA survey : Estimation of the clustering signal encoded in the cosmic variance

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    The relative cosmic variance (σv\sigma_v) is a fundamental source of uncertainty in pencil-beam surveys and, as a particular case of count-in-cell statistics, can be used to estimate the bias between galaxies and their underlying dark-matter distribution. Our goal is to test the significance of the clustering information encoded in the σv\sigma_v measured in the ALHAMBRA survey. We measure the cosmic variance of several galaxy populations selected with BB-band luminosity at 0.35z<1.050.35 \leq z < 1.05 as the intrinsic dispersion in the number density distribution derived from the 48 ALHAMBRA subfields. We compare the observational σv\sigma_v with the cosmic variance of the dark matter expected from the theory, σv,dm\sigma_{v,{\rm dm}}. This provides an estimation of the galaxy bias bb. The galaxy bias from the cosmic variance is in excellent agreement with the bias estimated by two-point correlation function analysis in ALHAMBRA. This holds for different redshift bins, for red and blue subsamples, and for several BB-band luminosity selections. We find that bb increases with the BB-band luminosity and the redshift, as expected from previous work. Moreover, red galaxies have a larger bias than blue galaxies, with a relative bias of brel=1.4±0.2b_{\rm rel} = 1.4 \pm 0.2. Our results demonstrate that the cosmic variance measured in ALHAMBRA is due to the clustering of galaxies and can be used to characterise the σv\sigma_v affecting pencil-beam surveys. In addition, it can also be used to estimate the galaxy bias bb from a method independent of correlation functions.Comment: Astronomy and Astrophysics, in press. 9 pages, 4 figures, 3 table

    Desarrollo de Modulo de Vivienda Desmontable

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    Con el paso del tiempo, la forma de habitar del ser humano va cambiando conforme a sus necesidades, la forma en la que vivimos repercute directamente en cómo habitamos. Los espacios, los materiales, la arquitectura, la función, las ciudades, los países, todo esto habla de momentos y experiencias de tiempos distintos por los que ha pasado el ser humano a lo largo de la vida. La realidad actual de México es una cantidad innumerable de personas sin hogar en situación de calle, construcciones genéricas y muchas de ellas en abandono, el director general de Estadísticas Sociodemográficas del Instituto, Edgar Vielma, reveló a periódico MILENIO que “Actualmente se desconoce cuántas personas sin hogar hay y los datos más recientes de 2011, elaborados por la Cepal estimaron que en México había 14 millones de personas en esta condición. “Sin hablar de la contaminación por la elección de materiales y procesos constructivos que dañan el medio ambiente, así como gran cantidad de personas habitando espacios que dañan directamente su calidad de vida, y muchas veces sin percibirlo. No solo en México, en el mundo esto es una realidad, tanto así que, según el BlogArquitectura México: “El sector de la Construcción es responsable de consumir el 50% de los recursos naturales, el 40% de la energía y del 50% del total de los residuos generados. Sin embargo, existen materiales y procesos constructivos que ayudan a disminuir drásticamente este daño. La construcción con madera es una opción con grandes beneficios para el planeta ya que, según la revista Venturelli “la madera es un material de características renovables que además ayuda a la reducción de emisiones de CO2 en el ambiente, convirtiéndola en una de las alternativas con las huellas de carbono más bajas a la hora de construir.” Además, es un material bastante fácil de trabajar, permitiendo a cualquier persona utilizarlo para distintas necesidades. En este trabajo se intentará responder a la realidad sobre los alcances de la madera en un sistema constructivo que permita la autoconstrucción, donde buscamos generar una estructura hiperestática formada por marcos de madera, los cuales trabajan en conjunto obteniendo una estructura rígida, de fácil armado y con diseño arquitectónicamente responsable

    Compositionality for Quantitative Specifications

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    We provide a framework for compositional and iterative design and verification of systems with quantitative information, such as rewards, time or energy. It is based on disjunctive modal transition systems where we allow actions to bear various types of quantitative information. Throughout the design process the actions can be further refined and the information made more precise. We show how to compute the results of standard operations on the systems, including the quotient (residual), which has not been previously considered for quantitative non-deterministic systems. Our quantitative framework has close connections to the modal nu-calculus and is compositional with respect to general notions of distances between systems and the standard operations

    Compilation of parameterized seismogenic sources in Iberia for the SHARE European-scale seismic source model.

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    Abstract: SHARE (Seismic Hazard Harmonization in Europe) is an EC-funded project (FP7) that aims to evaluate European seismic hazards using an integrated, standardized approach. In the context of SHARE, we are compiling a fully-parameterized active fault database for Iberia and the nearby offshore region. The principal goal of this initiative is for fault sources in the Iberian region to be represented in SHARE and incorporated into the source model that will be used to produce seismic hazard maps at the European scale. The SHARE project relies heavily on input from many regional experts throughout the Euro-Mediterranean region. At the SHARE regional meeting for Iberia, the 2010 Working Group on Iberian Seismogenic Sources (WGISS) was established; these researchers are contributing to this large effort by providing their data to the Iberian regional integrators in a standardized format. The development of the SHARE Iberian active fault database is occurring in parallel with IBERFAULT, another ongoing effort to compile a database of active faults in the Iberian region. The SHARE Iberian active fault database synthesizes a wide range of geological and geophysical observations on active seismogenic sources, and incorporates existing compilations (e.g., Cabral, 1995; Silva et al., 2008), original data contributed directly from researchers, data compiled from the literature, parameters estimated using empirical and analytical relationships, and, where necessary, parameters derived using expert judgment. The Iberian seismogenic source model derived for SHARE will be the first regional-scale source model for Iberia that includes fault data and follows an internationally standardized approach (Basili et al., 2008; 2009). This model can be used in both seismic hazard and risk analyses and will be appropriate for use in Iberian- and European-scale assessments

    Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

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    The unexpectedly high flux of cosmic ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the HighAltitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.Comment: 16 pages (including supplementary material), 5 figure

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

    The Gaia-ESO Survey : The analysis of high-resolution UVES spectra of FGK-type stars

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    Date of Acceptance: 01/09/2014Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 105 stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already observed 1447 FGK-type stars. Aims. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO second internal release and will be part of its first public release of advanced data products. Methods. The final parameter scale is tied to the scale defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. In addition, a set of open and globular clusters is used to evaluate the physical soundness of the results. Each of the implemented methodologies is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted medians of those from the individual methods. Results. The recommended results successfully reproduce the atmospheric parameters of the benchmark stars and the expected Teff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55 K for Teff, 0.13 dex for log g and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for Teff, 0.10-0.25 dex for log g and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method-to-method dispersion of the abundances varies between 0.10 and 0.20 dex. Conclusions. The Gaia-ESO sample of high-resolution spectra of FGK-type stars will be among the largest of its kind analyzed in a homogeneous way. The extensive list of elemental abundances derived in these stars will enable significant advances in the areas of stellar evolution and Milky Way formation and evolution.Peer reviewe
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