896 research outputs found

    A Multi-Membership Catalogue for 1876 Open Clusters using UCAC4 data

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    The main objective of this work is to determine the cluster members of 1876 open clusters, using positions and proper motions of the astrometric catalogue UCAC4. For this purpose we apply three different methods, all them based on a Bayesian approach, but with different formulations: a purely parametric method, another completely non-parametric algorithm, and a third, recently developed by Sampedro & Alfaro, using both formulations at different steps of the whole process. The first and second statistical moments of the members phase-space subspace, obtained after applying the three methods, are compared for every cluster. Although, on average, the three methods yield similar results, specific differences between them, as well as for some particular clusters, are also present. The comparison with other published catalogues shows good agreement. We have also estimated for the first time the mean proper motion for a sample of 18 clusters. The results are organized in a single catalogue formed by two main files, one with the most relevant information for each cluster, partially including that in UCAC4, and the other showing the individual membership probabilities for each star in the cluster area. The final catalogue, with an interface design that enables an easy interaction with the user, is available in electronic format at SSG-IAA (http://ssg.iaa.es/en/content/sampedro-cluster-catalog) website.Comment: Accepted for publication in MNRAS. 9 pages, 3 figures, 6 table

    Unique Continuation for Schr\"odinger Evolutions, with applications to profiles of concentration and traveling waves

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    We prove unique continuation properties for solutions of the evolution Schr\"odinger equation with time dependent potentials. As an application of our method we also obtain results concerning the possible concentration profiles of blow up solutions and the possible profiles of the traveling waves solutions of semi-linear Schr\"odinger equations.Comment: 23 page

    The Gaia-ESO Survey: pre-main-sequence stars in the young open cluster NGC 3293

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    Delgado, Antonio J. et. al.The young open cluster NGC3293 is included in the observing program of the Gaia-ESO survey (GES). The radial velocity values provided have been used to assign cluster membership probabilities by means of a single-variable parametric analysis. These membership probabilities are compared to the results of the photometric membership assignment of NGC3293, based on UBVRI photometry. The agreement of the photometric and kinematic member samples amounts to 65 per cent, and could increase to 70 per cent as suggested by the analysis of the differences between both samples. A number of photometric PMS candidate members of spectral type F are found, which are confirmed by the results from VPHAS photometry and SED fitting for the stars in common with VPHAS and GES data sets. Excesses at mid- and near-infrared wavelengths, and signs of H alpha emission, are investigated for them. Marginal presence of H alpha emission or infilling is detected for the candidate members. Several of them exhibit moderate signs of U excess and weak excesses at mid-IR wavelengths. We suggest that these features originate from accretion discs in their last stages of evolution.This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell' Istruzione, dell' Universita' e della Ricerca (MIUR) in the form of the grant 'Premiale VLT 2012'. The results presented here benefit from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. AJD, LS, EJA and MTC acknowledge financial support from the Spanish Ministerio de Economia y Competitividad, through grant AYA2013-40611-P. JLY acknowledges support from FCT (SFRH/BSAB/1423/2014 and UID/FIS/04434/2013). TM acknowledges financial support from Belspo for contract PRODEX GAIA-DPAC.Peer reviewe

    MS-EMC vs. NEGF: A comparative study accounting for transport quantum corrections

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    As electronic devices approach the nanometer scale, quantum transport theories have been recognized as the best option to reproduce their performance. Other possible trend, mainly focused on reducing the computational effort, is the inclusion of quantum effects in semi-classical simulators. This work presents a comparison between a NEGF simulator and a MS-EMC tool including S/D tunneling both applied on a DGSOI transistor

    Improving the analytical assessment of fish stocks by providing parameters of data quality via InterCatch

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    The last multiannual Community program for the collection, management and use of data in the fisheries sector (Commission Decision 2008/949/EC) stated the provision of precision levels and sampling intensities of the estimates at national level. However, the unequal compliance of this standard has hindered its application in stock assessment and the consequent scientific advice. The cost-benefit analysis of a sampling program, besides addressing logistical and economic constraints, should deepen the potential of the tools currently available. This article proposes to test the calculation, provision and use in stock assessment of extensively collected precision parameters. First, sampling intensities and coefficients of variation of fisheries-dependent parameters are calculated using the COST software, a statistical tool specifically designed to quantify uncertainty in marine sampled data. Secondly, alternative ways are explored to provide precision parameters to the stock assessment coordinators by using InterCatch, the existing ICES web-based system to submit national data and compile international catch matrices. Finally, the incorporation of these precision parameters in the assessment model is tested, through a stock assessed by statistical assessment models (such as SS3) which can account for sampling errors. Thus, it will be possible to quantify how errors in input data propagate through stock assessment models to affect harvest rules, and also to help identify the most cost-effective data collections that adequately support the advisory process

    Validación Inter-operador de Videobserver™

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    The purpose of this study was to evaluate the degree of interobserver reliability for the sport analysis company VIDEOBSERVER™. The football match corresponding to the 2014 World Cup final was used as the sample for the study. Data were collected on 28 players, including the actions of the goalkeepers and the players substituted during the match. This study was carried out in four phases: (i) a revision of the literature was performed to define the theoretical frame-work and the procedures to be followed; (ii) an observation system was created with the help of two experienced sports analysis technicians; (iii) a pilot study was carried out with the aim of verifying the operativity of the observation system; and (iv) the main study of inter-observer reliability was developed. The values of the kappa index, the standardized typical error and the intra-class correlation coefficient were used for the statistical analysis. The results showed a high level of inter-operator reliability, a statement which is supported by the high values of the intra-class correlation coefficient (both at the individual and collective level) and the small standardized typical error which were foundin this study. This study adds an innovative element of analysis consisting in the fact that the evaluation was carried out not only at the collective level but also at the individual level

    Assessment of Gate Leakage Mechanism Utilizing Multi-Subband Ensemble Monte Carlo

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    The inclusion in advanced device simulators of quantum effects different than standard confinement becomes mandatory to describe device behavior as technology approaches the nanometer scales. This work presents a model to include the gate leakage mechanism considering direct and trap assisted tunneling in Multi-Subband Ensemble Monte Carlo (MS-EMC) simulators. The tool is used for the study of FDSOI and FinFET devices
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