3,217 research outputs found

    Supernova siblings: assessing the consistency of properties of type Ia supernovae that share the same parent galaxies

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    Artículo escrito por un elevado número de autores, sólo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereWhile many studies have shown a correlation between properties of the light curves of SNe Ia and properties of their host galaxies, it remains unclear what is driving these correlations. We introduce a new direct method to study these correlations by analyzing "parent" galaxies that host multiple SNe Ia "siblings." Here, we search the Dark Energy Survey SN sample, one of the largest samples of discovered SNe, and find eight galaxies that hosted two likely SNe Ia. Comparing the light-curve properties of these SNe and recovered distances from the light curves, we find no better agreement between properties of SNe in the same galaxy as any random pair of galaxies, with the exception of the SN light-curve stretch. We show at 2.8σ significance that at least one-half of the intrinsic scatter of SNe Ia distance modulus residuals is not from common host properties. We also discuss the robustness with which we could make this evaluation with LSST, which will find 100× more pairs of galaxies, and pave a new line of study on the consistency of SNe Ia in the same parent galaxies. Finally, we argue that it is unlikely that some of these SNe are actually single, lensed SN with multiple imagesThe DES data management system is supported by the National Science Foundation under grant Nos. AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 30647

    Birds of a Feather? Magellan/IMACS spectroscopy of the ultra-faint satellites grus II, tucana IV, and tucana V

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    Artículo escrito por un elevado número de autores, sólo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereWe present Magellan/IMACS spectroscopy of three recently discovered ultra-faint Milky Way satellites, Grus II, Tucana IV, and Tucana V. We measure systemic velocities of vhel=-110.0 &pm; 0.5 kms-1, vhel= 15.9-1.7+1.8kms-1 and vhel=-36.2-2.2+2.5 kms-1 for the three objects, respectively. Their large relative velocities demonstrate that the satellites are unrelated despite their close physical proximity. We determine a velocity dispersion for Tuc IV of σ = 4.3-1.0+1.7km s-1 but we cannot resolve the velocity dispersions of the other two systems. For Gru II, we place an upper limit (90% confidence) on the dispersion of σ < 1.9 kms-1 and for Tuc V, we do not obtain any useful limits. All three satellites have metallicities below, but none has a detectable metallicity spread. We determine proper motions for each satellite based on Gaia astrometry and compute their orbits around the Milky Way. Gru II is on a tightly bound orbit with a pericenter of 25-7+6 kpc and orbital eccentricity of 0.45-0.05+0.08. Tuc V likely has an apocenter beyond 100 kpc and could be approaching the Milky Way for the first time. The current orbit of Tuc IV is similar to that of Gru II, with a pericenter of 25-8+11 kpc and an eccentricity of 0.36-0.06+0.13. However, a backward integration of the position of Tuc IV demonstrates that it collided with the Large Magellanic Cloud at an impact parameter of 4 kpc ∼120 Myr ago, deflecting its trajectory and possibly altering its internal kinematics. Based on their sizes, masses, and metallicities, we classify Gru II and Tuc IV as likely dwarf galaxies, but the nature of Tuc V remains uncertainThe DES participants from Spanish institutions are partially supported by MINECO under grants AYA2012-39559, ESP2013-48274, FPA2013-47986, and Centro de Excelencia Severo Ochoa SEV-2012-0234, some of which include ERDF funds from the European Union. This material is based upon work supported by the National Science Foundation under grant No. 113876

    Caso clínico: mujer joven con cáncer de parótida. Importancia de la anatomía en imágenes

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    RESUMEN INTRODUCCIÓN: Los tumores de las glándulas salivales son neoplasias clínica y morfológicamente heterogéneas; sus principales factores pronósticos son: la histología, el grado de malignidad y la extensión; por ello es de fundamental importancia la correcta evaluación para determinar los tratamientos más adecuados a realizar. OBJETIVOS: Demostrar la importancia de los estudios de imágenes, no sólo para el diagnóstico, sino también para determinar la extensión del tumor que define el tratamiento quirúrgico y la radioterapia postoperatoria. MATERIAL Y MÉTODOS: Paciente mujer de 29 años de edad, con diagnóstico de cáncer de parótida: el diagnóstico de la biopsia preoperatoria indicó carcinoma de tipo basaloide, tratada con cirugía y posterior radioterapia con IMRT (radioterapia de intensidad modulada). Antes del año presentó un nódulo en región premandibular izquierda, debajo de la cicatriz; se realizaron ecografía y TAC para evaluar el diagnóstico, posibilidad de reintervención quirúrgica y re-irradiación con IMRT. RESULTADOS: En la ecografía y TAC se confirmó el diagnóstico de recidiva y se decidió la reintervención quirúrgica. El diagnóstico histopatológico fue carcinoma de células basales con márgenes comprometidos. Se realizó radioterapia de intensidad modulada, previa planificación con TAC para delimitar la zona a irradiar y proteger los tejidos sanos. El tratamiento resultó en respuesta clínica completa y toxicidad aceptable que no alteró la calidad de vida de la paciente. Luego de 4 años de seguimiento está libre de enfermedad y llegó a tener un embarazo sin complicaciones. CONCLUSIONES: Los estudios de imágenes fueron de gran utilidad para el diagnóstico de la recidiva y determinar la posibilidad de una nueva intervención quirúrgica y tratamiento de radioterapia con curación de la paciente.http://www.anatclinar.com.ar/index.php/esFil: García, Pedro Emilio. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas; Argentina.Fil: Fernandéz, D. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas; Argentina.Fil: Avila, Rodolfo Esteban. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. Cátedra de Biología Celular, Histología y Embriología; Argentina.Fil: Samar, María Elena. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Histología y Embriología A; Argentina.Oncologí

    A Robot Model of OC-Spectrum Disorders : Design Framework, Implementation and First Experiments

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    © 2019 Massachusetts Institute of TechnologyComputational psychiatry is increasingly establishing itself as valuable discipline for understanding human mental disorders. However, robot models and their potential for investigating embodied and contextual aspects of mental health have been, to date, largely unexplored. In this paper, we present an initial robot model of obsessive-compulsive (OC) spectrum disorders based on an embodied motivation-based control architecture for decision making in autonomous robots. The OC family of conditions is chiefly characterized by obsessions (recurrent, invasive thoughts) and/or compulsions (an urge to carry out certain repetitive or ritualized behaviors). The design of our robot model follows and illustrates a general design framework that we have proposed to ground research in robot models of mental disorders, and to link it with existing methodologies in psychiatry, and notably in the design of animal models. To test and validate our model, we present and discuss initial experiments, results and quantitative and qualitative analysis regarding the compulsive and obsessive elements of OC-spectrum disorders. While this initial stage of development only models basic elements of such disorders, our results already shed light on aspects of the underlying theoretical model that are not obvious simply from consideration of the model.Peer reviewe

    Common bottlenose dolphins <i>Tursiops truncatus</i> of Pacific South America, asynoptic review of population identification data. Report of the IWC Scientific Committee Meeting SC/67A/SM/10, Bled, Slovenia, May 2017

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    We succinctly summarize population ID information for common bottlenose dolphins Tursiops truncatus of the Pacific coast of South America, covering four coastal range states. Phylogenetic uncertainties relate primarily to offshore vs. coastal (inshore) ecotypes and biogeographic borders between the five proposed populations (2 offshore, 3 coastal): Colombia-Ecuador Offshore stock (probably = ETP Offshore), Peru-Chile Offshore, Ecuador Coastal, Peru Coastal and an unique community (Pod-R) on the north-central coast of Chile. Main questions concern the extent of gene flow between the offshore stocks at one hand, and with -and between- the three coastal populations at the other hand. Seven cranial characters, four non-metric (separation of occipital condyles, pterygoid bone development, exostosis of periotic) and three metric (tooth width, antorbital process length, maximum width palatines), dorsal fin shape, body stockiness, mt-DNA (control region), habitat, prey composition, parasite load, behaviour and prevalence of some infectious diseases differentiate coastal from offshore forms. 'Pod-R' is the southernmost (29°15'S) and only confirmed coastal form community in Chilean waters, albeit with an offshore (falcate) dorsal fin. Bottlenose dolphins which regularly transit nearshore in the Lagos and Aysén regions (Chilean Patagonia) and occasionally enter deep fjords, present an offshore morphotype. We suggest that two other coastal areas in Chile where bottlenose dolphins have been documented over decades, one a ca. 60 km stretch of coastline centered at Valparaiso/Laguna Verde (33°10'S) in central Chile, and a 190 km coastline around the Mejillones Peninsula (23°10'S) in northern Chile, may not host coastal but offshore form animals. The continental border of the Atacama Trench off northern and northcentral Chile leaves an extremely narrow, steep shelf with nearshore deep water, locally with strong coastal upwelling and increased productivity. This habitat seems to attract oceanic cetaceans, including offshore T. truncatus, sperm whales, large balaenopterids, and other species. The southern distribution range of true coastal morphotype bottlenose dolphins in Pacific South America remains unknown but off Chile distance-to-shore may not be the reliable indicator of ecotype as it is further north in the study region

    Hedonic Quality or Reward? A Study of Basic Pleasure in Homeostasis and Decision Making of a Motivated Autonomous Robot

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    © The Author (s) 2016. Published by SAGE. This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 License (http://www.creativecommons.org/licenses/by/3.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).We present a robot architecture and experiments to investigate some of the roles that pleasure plays in the decision making (action selection) process of an autonomous robot that must survive in its environment. We have conducted three sets of experiments to assess the effect of different types of pleasure---related versus unrelated to the satisfaction of physiological needs---under different environmental circumstances. Our results indicate that pleasure, including pleasure unrelated to need satisfaction, has value for homeostatic management in terms of improved viability and increased flexibility in adaptive behavior.Peer reviewedFinal Published versio

    Quasar accretion disk sizes from continuum reverberation mapping in the DES standard-star fields

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    Measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. We present the accretion disk sizes of 22 quasars from continuum reverberation mapping with data from the Dark Energy Survey (DES) standard star fields and the supernova C fields. We construct continuum lightcurves with the \textit{griz} photometry that span five seasons of DES observations. These data sample the time variability of the quasars with a cadence as short as one day, which corresponds to a rest frame cadence that is a factor of a few higher than most previous work. We derive time lags between bands with both JAVELIN and the interpolated cross-correlation function method, and fit for accretion disk sizes using the JAVELIN Thin Disk model. These new measurements include disks around black holes with masses as small as 107\sim10^7 MM_{\odot}, which have equivalent sizes at 2500\AA \, as small as 0.1\sim 0.1 light days in the rest frame. We find that most objects have accretion disk sizes consistent with the prediction of the standard thin disk model when we take disk variability into account. We have also simulated the expected yield of accretion disk measurements under various observational scenarios for the Large Synoptic Survey Telescope Deep Drilling Fields. We find that the number of disk measurements would increase significantly if the default cadence is changed from three days to two days or one day.Comment: 33 pages, 24 figure

    Transfer learning for galaxy morphology from one survey to another

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    © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Deep Learning (DL) algorithms for morphological classification of galaxies have proven very successful, mimicking (or even improving) visual classifications. However, these algorithms rely on large training samples of labelled galaxies (typically thousands of them). A key question for using DL classifications in future Big Data surveys is how much of the knowledge acquired from an existing survey can be exported to a new dataset, i.e. if the features learned by the machines are meaningful for different data. We test the performance of DL models, trained with Sloan Digital Sky Survey (SDSS) data, on Dark Energy survey (DES) using images for a sample of \sim5000 galaxies with a similar redshift distribution to SDSS. Applying the models directly to DES data provides a reasonable global accuracy (\sim 90%), but small completeness and purity values. A fast domain adaptation step, consisting in a further training with a small DES sample of galaxies (\sim500-300), is enough for obtaining an accuracy > 95% and a significant improvement in the completeness and purity values. This demonstrates that, once trained with a particular dataset, machines can quickly adapt to new instrument characteristics (e.g., PSF, seeing, depth), reducing by almost one order of magnitude the necessary training sample for morphological classification. Redshift evolution effects or significant depth differences are not taken into account in this study.Peer reviewedFinal Accepted Versio
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