193 research outputs found

    Multi-Messenger Astronomy with Extremely Large Telescopes

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    The field of time-domain astrophysics has entered the era of Multi-messenger Astronomy (MMA). One key science goal for the next decade (and beyond) will be to characterize gravitational wave (GW) and neutrino sources using the next generation of Extremely Large Telescopes (ELTs). These studies will have a broad impact across astrophysics, informing our knowledge of the production and enrichment history of the heaviest chemical elements, constrain the dense matter equation of state, provide independent constraints on cosmology, increase our understanding of particle acceleration in shocks and jets, and study the lives of black holes in the universe. Future GW detectors will greatly improve their sensitivity during the coming decade, as will near-infrared telescopes capable of independently finding kilonovae from neutron star mergers. However, the electromagnetic counterparts to high-frequency (LIGO/Virgo band) GW sources will be distant and faint and thus demand ELT capabilities for characterization. ELTs will be important and necessary contributors to an advanced and complete multi-messenger network.Comment: White paper submitted to the Astro2020 Decadal Surve

    Characterizing the target selection pipeline for the Dark Energy Spectroscopic Instrument Bright Galaxy Survey

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    We present the steps taken to produce a reliable and complete input galaxy catalogue for the Dark Energy Spectroscopic Instrument (DESI) Bright Galaxy Survey (BGS) using the photometric Legacy Survey DR8 DECam. We analyse some of the main issues faced in the selection of targets for the DESI BGS, such as star–galaxy separation, contamination by fragmented stars and bright galaxies. Our pipeline utilizes a new way to select BGS galaxies using Gaia photometry and we implement geometrical and photometric masks that reduce the number of spurious objects. The resulting catalogue is cross-matched with the Galaxy And Mass Assembly (GAMA) survey to assess the completeness of the galaxy catalogue and the performance of the target selection. We also validate the clustering of the sources in our BGS catalogue by comparing with mock catalogues and the Sloan Digital Sky Survey (SDSS) data. Finally, the robustness of the BGS selection criteria is assessed by quantifying the dependence of the target galaxy density on imaging and other properties. The largest systematic correlation we find is a 7 per cent suppression of the target density in regions of high stellar density

    RETOS Y OPORTUNIDADES EN LA INTEGRACIÓN DE SOCIEDADES COOPERATIVAS

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    La presente publicación contiene las actas del Curso de Verano titulado “Retos y oportunidades en la integración de cooperativas” que se celebró en la sede de la Cartuja de Sevilla de la Universidad Internacional de Andalucía (UNIA) entre los días 11 a 15 de septiembre de 2017 y que se organizó en el marco del Proyecto Investigación de Excelencia de la Junta de Andalucía "Retos y oportunidades en la concentración e integración de empresas agroalimentaria" (P12-SEJ-2555) del que el profesor Vargas Vasserot es el Investigador Principal. Una de las peculiaridades que tuvo el curso es que gran parte de los asistentes eran a su vez especialistas en las materias impartidas y miembros del proyecto de investigación de la Junta de Andalucía que organizaba el curso, por lo que con objeto de darle mayor participación se habilitó la posibilidad de presentar comunicaciones científicas, como si fuera un congreso. Una vez terminado el curso, se vio que los materiales facilitados a los alumnos por los distintos profesores del curso junto a las comunicaciones científicas presentadas por parte de los asistentes era un material que debía ser puesto a disposición de todas las personas e instituciones interesadas en los procesos de integración de cooperativas y, además, sin mucha demora por la importancia que actualmente tienen todas estas cuestiones. Además de las ponencias y comunicaciones que se presentarons, hemos includio en la publicación un anexo con legislación y normativa de interés y los resultados de una encuesta sobre los procesos de integración realizada en el sector hortofrutícola almeriense que realizamos a lo largo de 2016 en el marco del citado proyecto de investigación de la Junta de Andalucía

    Frequency of Fabry disease in male and female haemodialysis patients in Spain

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    <p>Abstract</p> <p>Background</p> <p>Fabry disease (FD), an X-linked lysosomal storage disorder, is caused by a reduced activity of the lysosomal enzyme α-galactosidase A. The disorder ultimately leads to organ damage (including renal failure) in males and females. However, heterozygous females usually present a milder phenotype with a later onset and a slower progression.</p> <p>Methods</p> <p>A combined enzymatic and genetic strategy was used, measuring the activity of α-galactosidase A and genotyping the α-galactosidase A gene (<it>GLA</it>) in dried blood samples (DBS) of 911 patients undergoing haemodialysis in centers across Spain.</p> <p>Results</p> <p><it>GLA </it>alterations were found in seven unrelated patients (4 males and 3 females). Two novel mutations (p.Gly346AlafsX347 and p.Val199GlyfsX203) were identified as well as a previously described mutation, R118C. The R118C mutation was present in 60% of unrelated patients with <it>GLA </it>causal mutations. The D313Y alteration, considered by some authors as a pseudo-deficiency allele, was also found in two out of seven patients.</p> <p>Conclusions</p> <p>Excluding the controversial D313Y alteration, FD presents a frequency of one in 182 individuals (0.55%) within this population of males and females undergoing haemodialysis. Moreover, our findings suggest that a number of patients with unexplained and atypical symptoms of renal disease may have FD. Screening programmes for FD in populations of individuals presenting severe kidney dysfunction, cardiac alterations or cerebrovascular disease may lead to the diagnosis of FD in those patients, the study of their families and eventually the implementation of a specific therapy.</p

    A Stochastic Model of Latently Infected Cell Reactivation and Viral Blip Generation in Treated HIV Patients

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    Motivated by viral persistence in HIV+ patients on long-term anti-retroviral treatment (ART), we present a stochastic model of HIV viral dynamics in the blood stream. We consider the hypothesis that the residual viremia in patients on ART can be explained principally by the activation of cells latently infected by HIV before the initiation of ART and that viral blips (clinically-observed short periods of detectable viral load) represent large deviations from the mean. We model the system as a continuous-time, multi-type branching process. Deriving equations for the probability generating function we use a novel numerical approach to extract the probability distributions for latent reservoir sizes and viral loads. We find that latent reservoir extinction-time distributions underscore the importance of considering reservoir dynamics beyond simply the half-life. We calculate blip amplitudes and frequencies by computing complete viral load probability distributions, and study the duration of viral blips via direct numerical simulation. We find that our model qualitatively reproduces short small-amplitude blips detected in clinical studies of treated HIV infection. Stochastic models of this type provide insight into treatment-outcome variability that cannot be found from deterministic models

    The DESI Bright Galaxy Survey: Final Target Selection, Design, and Validation

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    Over the next 5 yr, the Dark Energy Spectroscopic Instrument (DESI) will use 10 spectrographs with 5000 fibers on the 4 m Mayall Telescope at Kitt Peak National Observatory to conduct the first Stage IV dark energy galaxy survey. At z 10 million galaxies spanning 14,000 deg2 . In this work, we present and validate the final BGS target selection and survey design. From the Legacy Surveys, BGS will target an r 80% fiber assignment efficiency. Finally, BGS Bright and BGS Faint will achieve >95% redshift success over any observing condition. BGS meets the requirements for an extensive range of scientific applications. BGS will yield the most precise baryon acoustic oscillation and redshift-space distortion measurements at z < 0.4. It presents opportunities for new methods that require highly complete and dense samples (e.g., N-point statistics, multitracers). BGS further provides a powerful tool to study galaxy populations and the relations between galaxies and dark matter
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