275 research outputs found

    A catalogue of velocities in the direction of the cluster of galaxies Abell 496

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    We present a catalogue of velocities for 466 galaxies in the direction of the cluster Abell 496, in a region covering about 160' x 160' (9.2 x 9.2 Mpc for an average redshift for Abell 496 of 0.0331, assuming H0_0=50 km s1^{-1} Mpc1^{-1}). This catalogue includes previously published redshifts by Proust et al. (1987), Quintana and Ramirez (1990) and Malumuth et al. (1992), redshifts from the CfA redshift survey, together with our new measurements. A total of 274 galaxies have velocities in the 7800-11800 km/s interval, and will be considered as members of the cluster. Abell 496 therefore becomes one of the few clusters with a high number of measured redshifts; its physical properties are investigated in a companion paper.Comment: Accepted for publication in Astronomy & Astrophysics, Supplement Serie

    Can family ownership influence firms' capital structure decisions?

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    The purpose of the present study is to endeavor the explanatory capacity of family ownership in determining the capital structure of the firms. Having this purpose in mind, we collect and analyze information for the period 2005-2013, regarding a sample of 194 family and non-family businesses, whose headquarters' location is in either European or North American countries. We obtain empirical evidence to conclude that i) non-family firms present higher leverage ratios compared to their family peers; and ii) non-family firms rely more on long-term debt than their family peers. Our study adds value to previous research since it compares companies from two different continents, (North) America and Europe, it analyzes how different firm characteristics may influence both leverage ratio and long-term debt to total debt and finally because it studies the impact of the financial crisis on the firms' financial results

    Invasibility and species richness of island endemic arthropods: a general model of endemic vs. exotic species

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    Copyright © 2005 Blackwell Publishing.This paper has two objectives. First, we examine how a variety of biotic, abiotic and anthropogenic factors influence the endemic and introduced arthropod richness on an oceanic island. Second, we look at the relationship between the endemic and introduced arthropod richness, to ask whether areas with high levels of endemic species richness deter invasions

    The galaxy luminosity function in the cluster of galaxies Abell 496

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    We have derived the galaxy luminosity function (GLF) in the cluster of galaxies Abell 496 from a wide field image in the I band. A single Schechter function reproduces quite well the GLF in the 17 <= I_{AB} <= 22 (-19.5 <= M_I <= -14.5) magnitude interval, and the power law index of this function is found to be somewhat steeper in the outer regions than in the inner regions. This result agrees with the idea that faint galaxies are more abundant in the outer regions of clusters, while in the denser inner regions they have partly been accreted by larger galaxies or have been dimmed or even disrupted by tidal interactions.Comment: Accepted for publication in Astronomy & Astrophysics, final versio

    TERT promoter mutations are a major indicator of poor outcome in differentiated thyroid carcinomas

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    Context: Telomerase promoter mutations (TERT) were recently described in follicular cell-derived thyroid carcinomas (FCDTC) and seem to be more prevalent in aggressive cancers. Objectives: We aimed to evaluate the frequency of TERT promoter mutations in thyroid lesions and to investigate the prognostic significance of such mutations in a large cohort of patients with differentiated thyroid carcinomas (DTCs). Design: This was a retrospective observational study. Setting and Patients: We studied 647 tumors and tumor-like lesions. A total of 469 patients with FCDTC treated and followed in five university hospitals were included. Mean follow-up (±SD) was 7.8 ± 5.8 years. Main Outcome Measures: Predictive value of TERT promoter mutations for distant metastasization, disease persistence at the end of follow-up, and disease-specific mortality. Results: TERT promoter mutations were found in 7.5% of papillary carcinomas (PTCs), 17.1% of follicular carcinomas, 29.0% of poorly differentiated carcinomas, and 33.3% of anaplastic thyroid carcinomas. Patients with TERT-mutated tumors were older (P < .001) and had larger tumors (P = .002). In DTCs, TERT promoter mutations were significantly associated with distant metastases (P < .001) and higher stage (P < .001). Patients with DTC harboring TERT promoter mutations were submitted to more radioiodine treatments (P = .009) with higher cumulative dose (P = .004) and to more treatment modalities (P = .001). At the end of follow-up, patients with TERT-mutated DTCs were more prone to have persistent disease (P = .001). TERT promoter mutations were significantly associated with disease-specific mortality [in the whole FCDTC (P < .001)] in DTCs (P < .001), PTCs (P = .001), and follicular carcinomas (P < .001). After adjusting for age at diagnosis and gender, the hazard ratio was 10.35 (95% confidence interval 2.01–53.24; P = .005) in DTC and 23.81 (95% confidence interval 1.36–415.76; P = .03) in PTCs. Conclusions: TERT promoter mutations are an indicator of clinically aggressive tumors, being correlated with worse outcome and disease-specific mortality in DTC. TERT promoter mutations have an independent prognostic value in DTC and, notably, in PTC.We acknowledge GENZYME for funding our work through a research project. This study was supported by the Portuguese Foundation for Science and Technology through PhD Grant SFRH/BD/81940/2011 (to J.V.); PhD Grant SFRH/BD/87887/2012 (to C.T.); PhD Grant SFRH/BD/79135/2011 (to A.A.); and the Scientific Investigation Project PIC/IC/83037/2007. Further funding was obtained from the project “Microenvironment, Metabolism and Cancer,” partially supported by Programa Operacional Regional do Norte (ON.2-O Novo Norte), under the Quadro de Referência Estratégico Nacional, and through the European Regional Development Fund. The work of J.M.C.-T. was supported by Grant PI12/00749-FEDER from the Instituto de Salud Carlos III, the Ministry of Economy and Competitiveness (Madrid, Spain). The Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP) is an associate laboratory of the Portuguese Ministry of Science, Technology, and Higher Education, which is partially supported by the Foundation for Science and Technology
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