24 research outputs found

    Infraestructuras de datos espaciales: desarrollo de habilidades espaciales en el entorno del Espacio Europeo de Educación Superior

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    [EN] In this work the results from a pilot study focused on university students are shown analyzing interaction between Geographic Information Technologies and development of spatial abilities. About the geoportal of Spain¿s Spatial Data Infrastructure, several exercises are completed for studying its influence over spatial skills where DAT-SR, MRT and Perspective Taking/Spatial Orientation tests are used.[ES] En este trabajo se muestran los resultados de un estudio piloto destinado a estudiantes universitarios en el que se analiza la interacción de las Tecnologías de Información Geográ- fica con el desarrollo de las habilidades espaciales. Usando el Geoportal de la Infraestructura de Datos Espaciales de España se realizan una serie de ejercicios al objeto de estudiar su influencia sobre las capacidades espaciales, para lo cual se emplean los test DAT-SR, MRT y Perspective Taking/Spatial Orientation Test.Carbonell Carrera, C.; Mejías, M.; Saorín Pérez, JL.; Contero González, MR. (2012). Infraestructuras de datos espaciales: desarrollo de habilidades espaciales en el entorno del Espacio Europeo de Educación Superior. Boletín de la Asociación de Geógrafos Españoles. (58):157-175. http://hdl.handle.net/10251/91854S1571755

    The polarized image of a synchrotron-emitting ring of gas orbiting a black hole

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    High Energy Astrophysic

    Constraints on black-hole charges with the 2017 EHT observations of M87*

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    InstrumentationHigh Energy Astrophysic

    The variability of the black hole image in M87 at the dynamical timescale

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    The black hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5–61 days) is comparable to the 6 day extent of the 2017 EHT observations. Closure phases along baseline triangles are robust interferometric observables that are sensitive to the expected structural changes of the images but are free of station-based atmospheric and instrumental errors. We explored the day-to-day variability in closure-phase measurements on all six linearly independent nontrivial baseline triangles that can be formed from the 2017 observations. We showed that three triangles exhibit very low day-to-day variability, with a dispersion of ∼3°–5°. The only triangles that exhibit substantially higher variability (∼90°–180°) are the ones with baselines that cross the visibility amplitude minima on the u–v plane, as expected from theoretical modeling. We used two sets of general relativistic magnetohydrodynamic simulations to explore the dependence of the predicted variability on various black hole and accretion-flow parameters. We found that changing the magnetic field configuration, electron temperature model, or black hole spin has a marginal effect on the model consistency with the observed level of variability. On the other hand, the most discriminating image characteristic of models is the fractional width of the bright ring of emission. Models that best reproduce the observed small level of variability are characterized by thin ring-like images with structures dominated by gravitational lensing effects and thus least affected by turbulence in the accreting plasmas.https://iopscience.iop.org/article/10.3847/1538-4357/ac332e/pdfPublished versio

    Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign

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    In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109Me. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.http://iopscience.iop.org/2041-8205am2022Physic

    International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

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    The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

    Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign

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    High Energy AstrophysicsInstrumentatio

    ePV-Trainer: Software for dimensioning stand-alone and grid-connected photovoltaic systems for educational purposes

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    ePV-Trainer is a user-friendly desktop application that allows users to dimension stand-alone and grid-connected photovoltaic systems. In addition, data on any geographic location in the world can be uploaded to the platform. The aim of this paper is to describe and assess the operation of the software developed in LabVIEW™. The study concludes with practical examples to verify that data delivered by the program match the one executed on manual calculations. The result is an intuitive software, which also allows to estimate the electricity generation of photovoltaic systems, based on real parameters of solar radiation and temperature. The software has been developed for educational purposes. © 2017 Elsevier Ltd
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