203 research outputs found

    Application of Genetic Algorithms to Transmit Code Problem of Synthetic Aperture Radar

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    This is the published version. Copyright De GruyterThis paper presents the design and. development of a genetic algorithm to compute an upper bound to evaluate a formal algorithm developed to solve the transmit code problem of Synthetic Aperture Radar (SAR). The input to the genetic algorithm is a set of propagation matrices that contain virtual information of the transformation of a signal transmitted and received by a SAR. The output is an upper bound approximately 11 times smaller than the results provided by the formal algorithm. The contributions of this paper are twofold: the upper bound found for the transmit code problem, and a tool that can be used for further research in similar domains

    El rol del gobierno electrónico en el derecho a la información. El derecho de acceso a la información pública y las tecnologías de información en Chile

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    Esta investigación tiene por objeto el estudio de la incidencia que tiene el Gobierno Electrónico en el ejercicio del derecho a la Información, enfocado en su variable de Acceso a la Información Pública. Así, emplea como dimensión orientadora y configuradora del presupuesto provisional básico, la constatación en Chile del Gobierno Electrónico como un entorno instrumental facilitador, que propicia el ejercicio del derecho de Acceso a la Información Pública, integrante del Gobierno de la Información, que centra su análisis en los flujos de información y en los derechos fundamentales que inciden en dichos flujos. Desarrollo El trabajo formula en su desarrollo, como primera aproximación, una exégesis histórica del derecho a la Información en Chile, en el contexto de la evolución de la sociedad de la información, contemplando una revisión de antecedentes normativos que van configurando este derecho, al alero de los progresos sociales y tecnológicos. Este estudio contempla desde los años 1812 y hasta 1980, en que se dicta la Constitución Política de la República actualmente vigente en Chile. Con posterioridad, se realiza un análisis del estatuto jurídico aplicable, centrándose, como primer elemento, en algunos aspectos que definen a la Carta Fundamental chilena de 1980, primordialmente en la concepción de “democracia protegida”, que le otorga ciertas características que se mantienen vigentes con ella, evidenciando la necesidad de efectuar cambios estructurales que permitan robustecer la democracia chilena..

    The Behavioral, Emotional, and Social Skills Inventory (BESSI): Psychometric Properties of a German-Language Adaptation, Temporal Stabilities of the Skills, and Associations with Personality and Intelligence

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    Social, emotional, and behavioral (SEB) skills comprise a broad set of abilities that are essential for building and maintaining relationships, regulating emotions, selecting and pursuing goals, or exploring novel stimuli. Toward an improved SEB skill assessment, Soto and colleagues recently introduced the Behavioral, Emotional, and Social Skills Inventory (BESSI). Measuring 32 facets from 5 domains with 192 items (assessment duration: ~15 min), BESSI constitutes the most extensive SEB inventory to date. However, so far, BESSI exists only in English. In three studies, we comprehensively validated a novel German-language adaptation, BESSI-G. Moreover, we expanded evidence on BESSI in three ways by (1) assessing the psychometric properties of the 32 individual skill facets, in addition to their domain-level structure; (2) providing first insights into the temporal stabilities of the 32 facets over 1.5 and 8 months; and (3) investigating the domains' and facets' associations with intelligence, in addition to personality traits. Results show that BESSI-G exhibits good psychometric properties (unidimensionality, reliability, factorial validity). Its domain-level structure is highly similar to that of the English-language source version. The facets show high temporal stabilities, convergent validity with personality traits, and discriminant validity with fluid and crystallized intelligence. We discuss implications for research on SEB skills.Soziale, emotionale und selbstregulatorischer Fähigkeiten (SEB) umfassen ein breites Spektrum von Fähigkeiten, die für den Aufbau und die Pflege von Beziehungen, die Regulierung von Emotionen, die Auswahl und Verfolgung von Zielen oder für die Erkundung neuer Reize unerlässlich sind. Auf dem Weg zu einer verbesserten Bewertung der SEB-Fähigkeiten haben Soto und Kolleg*innen vor kurzem das "Behavioral, Emotional, and Social Skills Inventory (BESSI)" eingeführt. Es misst 32 Facetten aus 5 Domänen mit 192 Items

    Hormonal milieu at time of B cell activation controls duration of autoantibody response

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    A strong gender bias is seen in many autoimmune diseases including systemic lupus erythematosus (SLE). To investigate the basis for the female preponderance in SLE, we have been studying BALB/c mice in which B cells express the R4A heavy chain of an anti-DNA antibody in association with an endogenous light chain repertoire (R4Atg mice). In unmanipulated mice, approximately 5% of B cells express the R4A transgene. R4Atg mice do not spontaneously develop elevated serum titers of anti-DNA antibodies. Administration of either estradiol (E2) or prolactin (Pr) results in escape from tolerance of autoreactive B cells, expressed as an increase in transgene-expressing B cells and elevated serum titers of anti-DNA antibodies. We previously demonstrated that autoreactive B cells maturing in an estrogenic milieu develop as marginal zone (MZ) B cells; when these same B cells mature in the presence of increased prolactin, they develop as follicular (Fo) B cells. To determine the long term consequence of this differential maturation of DNA-reactive B cells, we treated R4Atg BALB/c mice with E2 or Pr for 6 weeks until serum titers of anti-DNA antibody were high, at which time hormonal exposure was discontinued. In E2-treated mice, the anti-DNA titers remained high even 3 months after discontinuation of hormone exposure. Nascent B cells underwent normal tolerance induction, but existing autoreactive MZ B cells persisted and continued to secrete autoantibody. In contrast, Pr caused only a short-term increase in anti-DNA antibody titers. By 3 months after cessation of hormone treatment, serum anti-DNA antibody titers and B cell subsets were indistinguishable from those in placebo (P) treated mice. These findings suggest that autoantibody responses are sustained for variable lengths of time depending on the B cell subset producing the autoantibodies. This observation may be relevant to understanding the heterogeneous presentation of patients with SLE and to the design of therapies targeting specific B-cell populations in autoimmune disease. (C) 2014 Elsevier Ltd. All rights reserved

    Search for Gravitational Wave Bursts from Six Magnetars

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    Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects are characterized by repeated and sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures and excitation of non-radial modes which would emit gravitational waves (GWs). We present the results of a search for GW bursts from six galactic magnetars that is sensitive to neutron star f-modes, thought to be the most efficient GW emitting oscillatory modes in compact stars. One of them, SGR 0501+4516, is likely similar to 1 kpc from Earth, an order of magnitude closer than magnetars targeted in previous GW searches. A second, AXP 1E 1547.0-5408, gave a burst with an estimated isotropic energy >10(44) erg which is comparable to the giant flares. We find no evidence of GWs associated with a sample of 1279 electromagnetic triggers from six magnetars occurring between 2006 November and 2009 June, in GW data from the LIGO, Virgo, and GEO600 detectors. Our lowest model-dependent GW emission energy upper limits for band-and time-limited white noise bursts in the detector sensitive band, and for f-mode ringdowns (at 1090 Hz), are 3.0 x 10(44)d(1)(2) erg and 1.4 x 10(47)d(1)(2) erg, respectively, where d(1) = d(0501)/1 kpc and d(0501) is the distance to SGR 0501+4516. These limits on GW emission from f-modes are an order of magnitude lower than any previous, and approach the range of electromagnetic energies seen in SGR giant flares for the first time.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyItalian Istituto Nazionale di Fisica NucleareFrench Centre National de la Recherche ScientifiqueAustralian Research CouncilCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Educacion y CienciaConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsFoundation for Fundamental Research on Matter supported by the Netherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFoundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space Administration NNH07ZDA001-GLASTCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationRussian Space AgencyRFBR 09-02-00166aIPN JPL Y503559 (Odyssey), NASA NNG06GH00G, NASA NNX07AM42G, NASA NNX08AC89G (INTEGRAL), NASA NNG06GI896, NASA NNX07AJ65G, NASA NNX08AN23G (Swift), NASA NNX07AR71G (MESSENGER), NASA NNX06AI36G, NASA NNX08AB84G, NASA NNX08AZ85G (Suzaku), NASA NNX09AU03G (Fermi)Astronom

    Search for Gravitational Waves from Low Mass Compact Binary Coalescence in LIGO's Sixth Science Run and Virgo's Science Runs 2 and 3

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    We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009 and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25 solar masses; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90%-confidence rate upper limits of the binary coalescence of binary neutron star, neutron star- black hole and binary black hole systems are 1.3 x 10^{-4}, 3.1 x 10^{-5} and 6.4 x 10^{-6} Mpc^{-3}yr^{-1}, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.Comment: 11 pages, 5 figures. For a repository of data used in the publication, go to: . Also see the announcement for this paper on ligo.org at: <http://www.ligo.org/science/Publication-S6CBCLowMass/index.php

    Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts

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    Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to Oct 20 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ~50% or better probability with a few pointings of wide-field telescopes.Comment: 17 pages. This version (v2) includes two tables and 1 section not included in v1. Accepted for publication in Astronomy & Astrophysic

    First Low-Latency LIGO+Virgo Search for Binary Inspirals and their Electromagnetic Counterparts

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    Aims. The detection and measurement of gravitational-waves from coalescing neutron-star binary systems is an important science goal for ground-based gravitational-wave detectors. In addition to emitting gravitational-waves at frequencies that span the most sensitive bands of the LIGO and Virgo detectors, these sources are also amongst the most likely to produce an electromagnetic counterpart to the gravitational-wave emission. A joint detection of the gravitational-wave and electromagnetic signals would provide a powerful new probe for astronomy. Methods. During the period between September 19 and October 20, 2010, the first low-latency search for gravitational-waves from binary inspirals in LIGO and Virgo data was conducted. The resulting triggers were sent to electromagnetic observatories for followup. We describe the generation and processing of the low-latency gravitational-wave triggers. The results of the electromagnetic image analysis will be described elsewhere. Results. Over the course of the science run, three gravitational-wave triggers passed all of the low-latency selection cuts. Of these, one was followed up by several of our observational partners. Analysis of the gravitational-wave data leads to an estimated false alarm rate of once every 6.4 days, falling far short of the requirement for a detection based solely on gravitational-wave data.Comment: 13 pages, 13 figures. For a repository of data used in the publication, go to: http://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=P1100065 Also see the announcement for this paper on ligo.org at: http://www.ligo.org/science/Publication-S6CBCLowLatency

    Host–Parasite interactions in Entamoeba histolytica and Entamoeba dispar: what have we learned from their genomes?

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    Invasive amoebiasis caused by Entamoeba histolytica is a major global health problem. Virulence is a rare outcome of infection, occurring in fewer than 1 in 10 infections. Not all strains of the parasite are equally virulent, and understanding the mechanisms and causes of virulence is an important goal of Entamoeba research. The sequencing of the genome of E. histolytica and the related avirulent species Entamoeba dispar has allowed whole-genome-scale analyses of genetic divergence and differential gene expression to be undertaken. These studies have helped elucidate mechanisms of virulence and identified genes differentially expressed in virulent and avirulent parasites. Here, we review the current status of the E. histolytica and E. dispar genomes and the findings of a number of genome-scale studies comparing parasites of different virulence

    The Confidence Database

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    Understanding how people rate their confidence is critical for the characterization of a wide range of perceptual, memory, motor and cognitive processes. To enable the continued exploration of these processes, we created a large database of confidence studies spanning a broad set of paradigms, participant populations and fields of study. The data from each study are structured in a common, easy-to-use format that can be easily imported and analysed using multiple software packages. Each dataset is accompanied by an explanation regarding the nature of the collected data. At the time of publication, the Confidence Database (which is available at https://osf.io/s46pr/) contained 145 datasets with data from more than 8,700 participants and almost 4 million trials. The database will remain open for new submissions indefinitely and is expected to continue to grow. Here we show the usefulness of this large collection of datasets in four different analyses that provide precise estimations of several foundational confidence-related effects
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