278 research outputs found

    Combinando Linked Data con servicios geoespaciales

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    La Web de Linked Data supone un nuevo paradigma que pretende explotar la Web como un espacio global de información. La aplicación de los principios de esta nueva Web a la información geoespacial superará la integración de información tradicional, logrando una articulación semántica de los datos que haga desaparecer los silos de datos presentes en las actuales Infraestructuras de Datos Espaciales. Ante esta propuesta, en este artículo se describe el trabajo desarrollado en el marco de un caso de uso utilizando una parte de los datos del SIGNA. En este caso de uso se ha llevado a cabo un proceso de generación y publicación de los mencionados datos conforme a los principios de Linked Data y estos se combinan con diversos servicios de la IDEE y CartoCiudad para explotar el componente geoespacial

    Solar Energy Generation in Three Dimensions

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    We formulate, solve computationally and study experimentally the problem of collecting solar energy in three dimensions(1-5). We demonstrate that absorbers and reflectors can be combined in the absence of sun tracking to build three-dimensional photovoltaic (3DPV) structures that can generate measured energy densities (energy per base area, kWh/m2) higher by a factor of 2-20 than stationary flat PV panels, versus an increase by a factor of 1.3-1.8 achieved with a flat panel using dual-axis sun tracking(6). The increased energy density is countered by a higher solar cell area per generated energy for 3DPV compared to flat panel design (by a factor of 1.5-4 in our conditions), but accompanied by a vast range of improvements. 3DPV structures are steadier sources of solar energy generation at all latitudes: they can double the number of peak power generation hours and dramatically reduce the seasonal, latitude and weather variations of solar energy generation compared to a flat panel design. Self-supporting 3D shapes can create new schemes for PV installation and the increased energy density can facilitate the use of cheaper thin film materials in area-limited applications. Our findings suggest that harnessing solar energy in three dimensions can open new avenues towards Terawatt-scale generation.Comment: 40 pages, 16 pages paper (3 figures), 24 pages supplementary information (7 figures). Energy and Environmental Science (2012, Published on-line

    High energy gamma-ray sources in the VVV survey - II. The AGN counterparts

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    © 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We identified Active Galactic Nuclei (AGN) candidates as counterparts to unidentified gamma-ray sources (UGS) from the Fermi-LAT Fourth Source Catalogue at lower Galactic latitudes. Our methodology is based on the use of near- and mid-infrared photometric data from the VISTA Variables in the Vía Láctea (VVV) and Wide-field Infrared Survey Explorer (WISE) surveys. The AGN candidates associated with the UGS occupy very different regions from the stars and extragalactic sources in the colour space defined by the VVV and WISE infrared colours. We found 27 near-infrared AGN candidates possibly associated with 14 Fermi-LAT sources using the VVV survey. We also found 2 blazar candidates in the regions of 2 Fermi-LAT sources using WISE data. There is no match between VVV and WISE candidates. We have also examined the Ks light curves of the VVV candidates and applied the fractional variability amplitude (σrms) and the slope of variation in the Ks passband to characterise the near-infrared variability. This analysis shows that more than 85 per cent of the candidates have slopes in the Ks passband \gt;10−4 mag/day and present σrms values consistent with a moderate variability. This is in good agreement with typical results seen from type-1 AGN. The combination of YJHKs colours and Ks variability criteria was useful for AGN selection, including its use in identifying counterparts to Fermi γ-ray sources.Peer reviewe

    AGN candidates in the VVV near-IR galaxy catalogue

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    © 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1093/mnras/stad490The goal of this work is to search for Active Galactic Nuclei (AGN) in the Galactic disc at very low latitudes with |b|< 2°. For this, we studied the five sources from the VVV near-infrared (IR) galaxy catalogue that have also WISE counterparts and present variability in the VIrac VAriable Classification Ensemble (VIVACE) catalogue. In the near-IR colour-colour diagrams, these objects have in general redder colours compared to the rest of the sources in the field. In the mid-IR ones, they are located in the AGN region, however, there is a source that presents the highest interstellar extinction and different mid-IR colours to be a young stellar object (YSO). We also studied the source variability using two different statistical methods. The fractional variability amplitude σrms ranges from 12.6 to 33.8, being in concordance with previous results found for type-1 AGNs. The slopes of the light curves are in the range (2.6 - 4.7) × 10-4 mag d-1, also in agreement with results reported on quasars variability. The combination of all these results suggest that four galaxies are type-1 AGN candidates, whereas the fifth source likely a YSO candidate.Peer reviewe

    The VVV near-IR galaxy catalogue in a Northern part of the Galactic disc

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    The automated identification of extragalactic objects in large surveys provides reliable and reproducible samples of galaxies in less time than procedures involving human interaction. However, regions near the Galactic disc are more challenging due to the dust extinction. We present the methodology for the automatic classification of galaxies and non-galaxies at low Galactic latitude regions using both images and, photometric and morphological near-IR data from the VVVX survey. Using the VVV-NIRGC, we analyse by statistical methods the most relevant features for galaxy identification. This catalogue was used to train a CNN with image data and an XGBoost model with both photometric and morphological data and then to generate a dataset of extragalactic candidates. This allows us to derive probability catalogues used to analyse the completeness and purity as a function of the configuration parameters and to explore the best combinations of the models. As a test case, we apply this methodology to the Northern disc region of the VVVX survey, obtaining 172,396 extragalatic candidates with probabilities of being galaxies. We analyse the performance of our methodology in the VVV disc, reaching an F1-score of 0.67, a 65 per cent purity and a 69 per cent completeness. We present the VVV-NIR Galaxy Catalogue: Northern part of the Galactic disc comprising 1,003 new galaxies, with probabilities greater than 0.6 for either model, with visual inspection and with only 2 previously identified galaxies. In the future, we intend to apply this methodology to other areas of the VVVX survey.Comment: 12 pages, 14 figures, accepted in MNRA

    Comparative In Vitro Activity of Ceftolozane/Tazobactam against Clinical Isolates of Pseudomonas aeruginosa and Enterobacterales from Five Latin American Countries

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    Background: Ceftolozane/tazobactam (C/T) is a combination of an antipseudomonal oxyiminoaminothiazolyl cephalosporin with potent in vitro activity against Pseudomonas aeruginosa and tazobactam, a known β-lactamase inhibitor. The aim of this study was to evaluate the activity of C/T against clinical isolates of P. aeruginosa and Enterobacterales collected from five Latin American countries between 2016 and 2017, before its clinical use in Latin America, and to compare it with the activity of other available broad-spectrum antimicrobial agents. Methods: a total of 2760 clinical isolates (508 P. aeruginosa and 2252 Enterobacterales) were consecutively collected from 20 hospitals and susceptibility to C/T and comparator agents was tested and interpreted following the current guidelines. Results: according to the CLSI breakpoints, 68.1% (346/508) of P. aeruginosa and 83.9% (1889/2252) of Enterobacterales isolates were susceptible to C/T. Overall, C/T demonstrated higher in vitro activity than currently available cephalosporins, piperacillin/tazobactam and carbapenems when tested against P. aeruginosa, and its performance in vitro was comparable to fosfomycin. When tested against Enterobacterales, it showed higher activity than cephalosporins and piperacillin/tazobactam, and similar activity to ertapenem. Conclusions: these results show that C/T is an active β-lactam agent against clinical isolates of P. aeruginosa and Enterobacterales.Fil: García Betancur, Juan Carlos. Universidad El Bosque;Fil: De La Cadena, Elsa. Universidad El Bosque;Fil: Mojica, María F.. Universidad El Bosque; . Case Western Reserve University; Estados UnidosFil: Hernández Gómez, Cristhian. Universidad El Bosque;Fil: Correa, Adriana. Universidad Santiago de Cali; ColombiaFil: Radice, Marcela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquÍmica. Instituto de Investigaciones En Bacteriología y Virología Molecular (IBaViM); ArgentinaFil: Castañeda Méndez, Paulo. Fundacion Clinica Medica Sur; MéxicoFil: Jaime Villalon, Diego A.. Fundacion Clinica Medica Sur; MéxicoFil: Gales, Ana C.. Universidade Federal de Sao Paulo; BrasilFil: Munita, José M.. Universidad del Desarrollo; ChileFil: Villegas, María Virginia. Universidad El Bosque

    Plasma Dynamics

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    Contains reports on eight research projects split into two sections.National Science Foundation (Grant ENG79-07047)U.S. Air Force - Office of Scientific Research (Grant AFOSR-77-3143D)U.S. Department of Energy (Contract DE-ACO2-78ET-51013)U.S. Department of Energy (Contract DE-ACO2-78ET-53073.AO02)U.S. Department of Energy (Contract DE-ACO2-78ET-53074)U.S. Department of Energy (Contract DE-ACO2-78ET-53076)U.S. Department of Energy (Contract DE-ACO2-78ET-51002

    ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries

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    This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors

    Plasma Dynamics

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    Contains reports on ten research projects split into two sections.National Science Foundation (Grant ENG77-00340)U.S. Department of Energy (Contract EY-76-S-02-2766)U.S. Air Force - Office of Scientific Research (Grant AFOSR-77-3143)U.S. Department of Energy (Contract ET-78-C-01-3019)U.S. Department of Energy (Contract ET-78-S-02-4681)U.S. Department of Energy (Contract ET-78-S-02-4682)U.S. Department of Energy (Grant EG-77-G-01-4107)U.S. Department of Energy (Contract ET-78-S-02-4714)U.S. Department of Energy (Contract ET-78-S-02-4886)U.S. Department of Energy (Contract ET-78-S-02-4690
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