127 research outputs found

    Forming the first planetary systems: debris around Galactic thick disc stars

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    The thick disc contains stars formed within the first Gyr of Galactic history, and little is known about their planetary systems. The Spitzer MIPS instrument was used to search 11 of the closest of these old low-metal stars for circumstellar debris, as a signpost that bodies at least as large as planetesimals were formed. A total of 22 thick disc stars has now been observed, after including archival data, but dust is not found in any of the systems. The data rule out a high incidence of debris among star systems from early in the Galaxy's formation. However, some stars of this very old population do host giant planets, at possibly more than the general incidence among low-metal Sun-like stars. As the Solar System contains gas giants but little cometary dust, the thick disc could host analogue systems that formed many Gyr before the Sun.Comment: accepted by MNRAS Letters; 5 pages, 4 figure

    Researching Of Ranking Handball Referees' Job Satisfaction Levels In Terms Of Some Parameters,

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    This research has been conducted in order to determine the job satisfaction levels of the ranking referees in terms of some parameters (sex, age, marital status, income states, other profession, and refereeing period). This research is a descriptive study towards the review of job satisfaction levels of Handball ranking referees. Referees take charge in 2010-11 season in Turkish leagues constitute the population of the research. Accordingly 107 Ranking referees under Turkish Handball Federation constitute the sample of the research. SPSS package program was used for the statistical analyses. Measuring tool is constituted of two sections. In first section a test directed towards to determine the demographical features of the referees while in second section “Minnesota job satisfaction scale” was used. Validity and reliability studies were made (cronbach alpha =0.70). It was determined that statistically there is not a significant gap between the job satisfaction levels of the referees according to their sex, marital status, ranking position, refereeing periods and income status; and statistically there is a significant gap between their job satisfaction levels according to their ages. Increase of job satisfaction with the increase of age, increase of the experience, awards, rise of refereeing ranking and coalescence with the job are considered to be the factors for the existence of such difference. Income levels of the majority of the referees are seen to be at intermediate level

    YĂŒksekĂ¶ÄŸretimde Spor Eğitimi Veren Kurumlarda Görev Yapan Akademik Personelin Elektronik Ticaret Hakkındaki GörĂŒĆŸleri,

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    In this study the views of the academic personnel working in institutions giving sports training at higher education level in Turkey about electronic trade has been researched. Sample of the study is constituted by 214 academic personnel working in institutions giving sports training at higher education level in Turkey. Validity and reliability study improved by Sevindik (16) was made to determine the views of the participants and “e-Trade User View Form” was used. SPSS 11.5 package program was used in assessment of the questionnaires and t-test, Variance Analysis (ANOVA), Kruskal Wallis Test and LSD test analyses were made. As a result it was observed that, 86% of the academic personnel working in institutions giving sports training at higher education level in Turkey expressed the importance of electronic trade, 81,3% of them expressed that they used electronic banking system and 59,9% of them emphasized that electronic trade eliminates the traditional trade. Furthermore it was determined that there was a significant difference between the views of the participants towards electronic trade according to the variants of sex and education

    Analyzing Of Levels Of Job Satisfaction Of Volleyball Classification Referees In The Terms Of Some Parameters,

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    This research was carried out in order to determine the levels of job satisfaction of volleyball classification referees in the terms of some parameters (gender, age, marital status, duration of refereeing). The referees carrying out a duty in the Turkey leagues of 2011-2012 seasons constitute the nature of the research. At the same time, 136 classification referees who were selected randomly between 440 classification referees depend on the Volleyball Federation of Turkey constitute its sample. SPSS packaged software was used for the statistical analysis. Measurement tool consists of two parts. The evaluation was carried out intended for determine the demographic characteristics of the referees in the first section, "Minnesota Job Satisfaction Scale" was used in the second section. Validity and reliability studies were carried out and reliability co-efficient (cronbach alpha) was found as 0.75. Determined that there is no difference statistically between levels of the job satisfaction of the referees according to their genders, also there is significant difference statistically between levels of the intrinsic job satisfaction of the referees according to their ages, marital status and duration of the refereeing. As a result, it is concluded that as age goes by, job satisfaction is increasing in the parallel of this, increasing of the experience and authority depending on the duration of refereeing, integration of reward and referees works are effective in the emergence of this difference

    Chemical gradients in the Milky Way from the RAVE data

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    Aims. We aim at measuring the chemical gradients of the elements Mg, Al, Si, and Fe along the Galactic radius to provide new constraints on the chemical evolution models of the Galaxy and Galaxy models such as the Besancon model. Thanks to the large number of stars of our RAVE sample we can study how the gradients vary as function of the distance from the Galactic plane. Methods. We analysed three different samples selected from three independent datasets: a sample of 19 962 dwarf stars selected from the RAVE database, a sample of 10 616 dwarf stars selected from the Geneva-Copenhagen Survey (GCS) dataset, and a mock sample (equivalent to the RAVE sample) created by using the GALAXIA code, which is based on the Besancon model. The three samples were analysed by using the very same method for comparison purposes. We integrated the Galactic orbits and obtained the guiding radii (R-g) and the maximum distances from the Galactic plane reached by the stars along their orbits (Z(max)). We measured the chemical gradients as functions of R-g at different Z(max). Results. We found that the chemical gradients of the RAVE and GCS samples are negative and show consistent trends, although they are not equal: at Z(max) < 0.4 kpc and 4.5 < R-g(kpc) < 9.5, the iron gradient for the RAVE sample is d[Fe/H]/dR(g) = -0.065 dex kpc(-1), whereas for the GCS sample it is d[Fe/H]/dR(g) = -0.043 dex kpc(-1) with internal errors of +/-0.002 and +/-0.004 dex kpc(-1), respectively. The gradients of the RAVE and GCS samples become flatter at larger Z(max). Conversely, the mock sample has a positive iron gradient of d[Fe/H]/dR(g) = +0.053 +/- 0.003 dex kpc(-1) at Z(max) < 0.4 kpc and remains positive at any Z(max). These positive and unrealistic values originate from the lack of correlation between metallicity and tangential velocity in the Besancon model. In addition, the low metallicity and asymmetric drift of the thick disc causes a shift of the stars towards lower R-g and metallicity which, together with the thin-disc stars with a higher metallicity and R-g, generates a fictitious positive gradient of the full sample. The flatter gradient at larger Z(max) found in the RAVE and the GCS samples may therefore be due to the superposition of thin-and thick-disc stars, which mimicks a flatter or positive gradient. This does not exclude the possibility that the thick disc has no chemical gradient. The discrepancies between the observational samples and the mock sample can be reduced by i) decreasing the density; ii) decreasing the vertical velocity; and iii) increasing the metallicity of the thick disc in the Besancon model

    Thick disk kinematics from RAVE and the solar motion

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    Radial velocity surveys such as the Radial Velocity Experiment (RAVE) provide us with measurements of hundreds of thousands of nearby stars most of which belong to the Galactic thin, thick disk or halo. Ideally, to study the Galactic disks (both thin and thick) one should make use of the multi-dimensional phase-space and the whole pattern of chemical abundances of their stellar populations. In this paper, with the aid of the RAVE Survey, we study the thin and thick disks of the Milky Way, focusing on the latter. We present a technique to disentangle the stellar content of the two disks based on the kinematics and other stellar parameters such as the surface gravity of the stars. Using the Padova Galaxy Model, we checked the ability of our method to correctly isolate the thick disk component from the Galaxy mixture of stellar populations. We introduce selection criteria in order to clean the observed radial velocities from the Galactic differential rotation and to take into account the partial sky coverage of RAVE. We developed a numerical technique to statistically disentangle thin and thick disks from their mixture. We deduce the components of the solar motion relative to the Local Standard of Rest (LSR) in the radial and vertical direction, the rotational lag of the thick disk component relative to the LSR, and the square root of the absolute value of the velocity dispersion tensor for the thick disk alone. The analysis of the thin disk is presented in another paper. We find good agreement with previous independent parameter determinations. In our analysis we used photometrically determined distances. In the Appendix we show that similar values can be found for the thick disk alone as derived in the main sections of our paper even without the knowledge of photometric distances.Comment: accepted on A&A, please see companion paper "THIN disk kinem...

    Ultracool dwarf benchmarks with \emph{Gaia} primaries

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We explore the potential of \emph{Gaia} for the field of benchmark ultracool/brown dwarf companions, and present the results of an initial search for metal-rich/metal-poor systems. A simulated population of resolved ultracool dwarf companions to \emph{Gaia} primary stars is generated and assessed. Of order ∌\sim24,000 companions should be identifiable outside of the Galactic plane (∣b∣>10 |b| > 10\,deg) with large-scale ground- and space-based surveys including late M, L, T, and Y types. Our simulated companion parameter space covers 0.02≀M/M⊙≀0.10.02 \le M/M_{\odot} \le 0.1, 0.1≀age/Gyr≀140.1 \le {\rm age/Gyr} \le 14, and −2.5≀[Fe/H]≀0.5-2.5 \le {\rm [Fe/H]} \le 0.5, with systems required to have a false alarm probability 0.6\, kau}\,Peer reviewedFinal Accepted Versio

    Discovery of the benchmark metal poor T8 dwarf BD+01 2920B

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    We have searched the WISE first data release for widely separated (<10,000AU) late T dwarf companions to Hipparcos and Gliese stars. We have discovered a new binary system containing a K-band suppressed T8p dwarf WISEP J1423+0116 and the mildly metal poor ([Fe/H]=-0.38+-0.06) primary BD+01 2920 (Hip 70319), a G1 dwarf at a distance of 17.2pc. This new benchmark has Teff=680+-55K and a mass of 20-50 Mjup. Its spectral properties are well modelled except for known discrepancies in the Y and K bands. Based on the well determined metallicity of its companion, the properties of BD+01 2920B imply that the currently known T dwarfs are dominated by young low-mass objects. We also present an accurate proper motion for the T8.5 dwarf WISEP J075003.84+272544.8.Comment: MNRAS, accepted 2012 January 1

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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