5,602 research outputs found

    A Method to Unambiguously Determine the Parity of the Theta+ Pentaquark

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    With the recent discovery of the Θ(1540)\Theta(1540) pentaquark, the question of its parity is paramount since this will constrain the correct description of its internal structure. We show that the measurement of the spin singlet and triplet cross sections for the reaction p⃗p⃗→Σ+Θ+\vec{p}\vec{p} \to \Sigma^+ \Theta^+ will unambiguously determine the parity of the Θ+\Theta^+.Comment: 3 page

    The First Seasat-A Industrial Users Workshop

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    The purpose of this workshop was to begin the process of definition and development of the SEASAT-A Demonstration Program, leading to the implementation of a set of experiments which would begin during the latter part of 1978 following the launch of SEASAT-A (now scheduled for May 1978). NASA through the SEASAT-A program, has encouraged the planning of cooperative experiments by industry and government agencies that operate in areas of ocean activity that could benefit from improved measurements and forecasts of weather and ocean conditions. The objectives of these experiments are to: (1) evaluate the significance of SEASAT-A data to commercial user organizations; (2) assist in identifying those characteristics of follow-on systems that are important to industrial users; (3) obtain experimental evidence that could be used to refine estimates of the economic potential of an operational system; and (4) begin the technology transfer process to the industrial users

    Estrategias de formulación de los mercados de abasto y su influencia en la sociedad y cultura

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    Los mercados de abasto es una de las infraestructuras más antiguas de comercialización que convive con el retail moderno, manteniendo su posicionamiento, gracias no solo a la ventaja competitiva del producto fresco sino a los impactos sociales y culturales que generan. Por otro lado los supermercados y su gran desarrollo logístico operacional y fuerte crecimiento, han modificado los hábitos de compra del consumidor, con la creación de distintos formatos de venta, posicionándose cada vez más en la preferencia de compra, pudiéndose perder ese potencial beneficio sociocultural, por lo que los mercados de abasto tradicionales necesitan implementar nuevas estrategias que les permita seguir desarrollando esos aspectos relevantes de la sociedad, recuperando sus orígenes de ser edificaciones potencialmente influyentes de su entorno, a través de intervenciones que generan vinculaciones sociales y culturales, encontrándose en la investigación soluciones como: Beneficios sociales a través de la integración estratégica de comerciantes y vecinos, Beneficios urbanos a través de la integración con su entorno, Beneficios culturales a través de nuevos servicios con valor agregado, mejoras de los servicios internos implementando el diseño emocional y merchandising en la exhibición

    Multiwavelength Mass Comparisons of the z~0.3 CNOC Cluster Sample

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    Results are presented from a detailed analysis of optical and X-ray observations of moderate-redshift galaxy clusters from the Canadian Network for Observational Cosmology (CNOC) subsample of the EMSS. The combination of extensive optical and deep X-ray observations of these clusters make them ideal candidates for multiwavelength mass comparison studies. X-ray surface brightness profiles of 14 clusters with 0.17<z<0.55 are constructed from Chandra observations and fit to single and double beta-models. Spatially resolved temperature analysis is performed, indicating that five of the clusters in this sample exhibit temperature gradients within their inner 60-200 kpc. Integrated spectra extracted within R_2500 provide temperature, abundance, and luminosity information. Under assumptions of hydrostatic equilibrium and spherical symmetry, we derive gas and total masses within R_2500 and R_200. We find an average gas mass fraction within R_200 of 0.136 +/- 0.004, resulting in Omega_m=0.28 +/- 0.01 (formal error). We also derive dynamical masses for these clusters to R_200. We find no systematic bias between X-ray and dynamical methods across the sample, with an average M(dyn)/M(X-ray) = 0.97 +/- 0.05. We also compare X-ray masses to weak lensing mass estimates of a subset of our sample, resulting in a weighted average of M(lens)/M(X-ray) of 0.99 +/- 0.07. We investigate X-ray scaling relationships and find powerlaw slopes which are slightly steeper than the predictions of self-similar models, with an E(z)^(-1) Lx-Tx slope of 2.4 +/- 0.2 and an E(z) M_2500-Tx slope of 1.7 +/- 0.1. Relationships between red-sequence optical richness (B_gc,red) and global cluster X-ray properties (Tx, Lx and M_2500) are also examined and fitted.Comment: Astrophysical Journal, 48 pages, 11 figures, LaTeX. Added correction to surface brightness normalization of MS1512.4+3647, corrections to sample gas mass fractions and calculated value of Omega_m. Figure resolution has been reduced to comply with astro-ph upload requirement

    Circumnuclear Gas in Seyfert 1 Galaxies: Morphology, Kinematics, and Direct Measurement of Black Hole Masses

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    (Abridged) The two-dimensional distribution and kinematics of the molecular, ionized, and highly ionized gas in the nuclear regions of Seyfert 1 galaxies have been measured using high spatial resolution (~0''.09) near-infrared spectroscopy from NIRSPEC with adaptive optics on the Keck telescope. Molecular hydrogen, H2, is detected in all nine Seyfert 1 galaxies and, in the majority of galaxies, has a spatially resolved flux distribution. In contrast, the narrow component of the BrG emission has a distribution consistent with that of the K-band continuum. In general, the kinematics of H2 are consistent with thin disk rotation, with a velocity gradient of over 100 km/s measured across the central 0''.5 in three galaxies, and across the central 1''.5 in two galaxies. The kinematics of BrG are in agreement with the H2 rotation, except in all four cases the central 0''.5 is either blue- or redshifted by more than 75 km/s. The highly ionized gas, measured with the [Ca VIII] and [Si VII] coronal lines, is spatially and kinematically consistent with BrG in the central 0''.5. Dynamical models have been fitted to the two-dimensional H2 kinematics, taking into account the stellar mass distribution, the emission line flux distribution, and the point spread function. For NGC 3227 the modeling indicates a black hole mass of Mbh = 2.0{+1.0/-0.4} x 10^7 Msun, and for NGC 4151 Mbh = 3.0{+0.75/-2.2} x 10^7 Msun. In NGC 7469 the best fit model gives Mbh < 5.0 x 10^7 Msun. In all three galaxies, modeling suggests a near face-on disk inclination angle, which is consistent with the unification theory of active galaxies. The direct black hole mass estimates verify that masses determined from the technique of reverberation mapping are accurate to within a factor of three with no additional systematic errors.Comment: 43 pages, including 47 figures; Accepted for publication in ApJ. All 2-D maps (in high resolution) are available at http://www.astro.ucla.edu/~ehicks . Minor changes to the text and updated reverberation mapped black hole mass estimates; the conclusions are unchange
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