2,594 research outputs found

    Long slit spectroscopy of a sample of isolated spirals with and without an AGN

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    We present the kinematical data obtained for a sample of active (Seyfert) and non active isolated spiral galaxies, based on long slit spectra along several position angles in the Halpha line region and, in some cases, in the Ca triplet region as well. Gas velocity distributions are presented, together with a simple circular rotation model that allows to determine the kinematical major axes. Stellar velocity distributions are also shown. The main result is that active and control galaxies seem to be equivalent in all kinematical aspects. For both subsamples, the departure from pure circular rotation in some galaxies can be explained by the presence of a bar and/or of a spiral arm. They also present the same kind of peculiarities, in particular, S-shape structures are quite common near the nuclear regions. They define very similar Tully-Fisher relations. Emission line ratios are given for all the detected HII regions; the analysis of the [NII]/Halpha metallicity indicator shows that active and non-active galaxies have indistinguishable disk metallicities. These results argue in favour of active and non-active isolated spiral galaxies having essentially the same properties, in agreement with our previous results based on the analysis of near infrared images. It appears now necessary to confirm these results on a larger sample.Comment: 35 pages, 54 figures, Accepted for publication in Astronomy & Astrophysics The full paper with its figures is available on the anonymous account of ftp.iap.fr in /home/ftp/pub/from_users/durret/marquez.ps.gz (999 kb

    1020 steel coated with Ti/TiN by Cathodic Arc and Ion Implantation

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    TiN coatings have been widely studied in order to improve mechanical properties of steels. In this work, thin Ti/TiN films were prepared by plasma based immersion ion implantation and deposition (PBII&D) with a cathodic arc on AISI 1020 steel substrates. Substrates were exposed to the discharge during 1 min in vacuum for the deposition of a Tiunderlayer with the aim of improving the adhesion to the substrate. Then, a TiN layer was deposited during 6 min in a nitrogen environment at a pressure of 3xl0-4 mbar. Samples were obtained at room temperature and at 300 °C, and with or without ion implantation in order to analyze differences between the effects of each treatment on the tribological properties. The mechanical and tribological properties of the films were characterized. The coatings deposited by PBII&D at 300 °C presented the highest hardness and young modulus, the best wear resistance and corrosion performance.Fil: Bermeo, Diego Fernando. Universidad Santiago de Cali; ColombiaFil: Quintana, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; ArgentinaFil: Kleiman, Ariel Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; ArgentinaFil: Sequeda, F.. Universidad del Valle; ColombiaFil: Márquez, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin

    The teaching strategies in the Teaching-Learning proccess of reading skill in eleventh grade, section B at public high school "Augusto Calderon Sandino" in Niquinohomo during the period from March to Octuber 2014

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    Over the last twenty years, there has been growing interest in incorporating a significant focus on Reading skill into the language curricula. There is a general belief that such focus will help students become more successful learners and it facilitates the activation of the comprehension. It is also assumed that learners who have developed skills in Reading will be able to exploit classroom-learning opportunities effectively, and they will be more adequately equipped to continue with language learning outside the classroom. Reading is the most basic skill, it provides access to other skills and knowledge, facilitates life-long learning, and it opens doors to opportunities in life in several aspects.Thi

    Aplicación de la bioacústica al seguimiento de anfibios

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    Los proyectos TEMPURA: (CGL2005- 00092/BOS) y ACOURA (CGL2008-04814-C02) fueron financiados por el Ministerio de Ciencia e Innovación del Gobierno de España. Actualmente, continuamos los estudios de bioacústica de anuros con fondos del Ministerio de Economía y Competitividad del Gobierno de España. (proyecto TATANKA, CGL2001/25062)Peer reviewe

    A statistical analysis of electric self-potential time series associated to two 1993 earthquakes in Mexico

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    Recent studies related with earthquake prediction involve statistical studies of the ground electric self-potential behavior. Published results about the complexity of this kind of processes encourage us to study the statistical behavior of the ground electric self-potential recorded in Guerrero state, Mexico. This region is characterized by high seismicity. The electric self-potential variations were recorded in the Acapulco station directly from the ground. The sampling period was four seconds and the data were stored from March to December of 1993. Two significant earthquakes (EQs) occurred near this station, 15 May and 24 October whose magnitudes were Mw=6.0 and Mw=6.6 respectively. A preliminary processing was carried out consisting of a moving average of the original time series in order to filter the very high frequencies and to complete short lacks of data and outliers. Then, a visual inspection of the complete filtered signal was performed to search some seismic electric signals (SES), which were ambiguously depicted. Subsequently, a detrending of µ=0 was applied with the windows of 3.3, 6.6 and 10 h. Later, the analysis of the spectral exponent β was made, showing changes during the total period examined, and the most evident changes occurred during the preparation mechanism of the Mw=6.6 EQ. Fifteen days before the 24 October EQ, a Brownian-noise like behavior was displayed (β≈2), having a duration of about two days. In addition a Higuchi fractal method and wavelet analysis were made confirming the presence of the β-anomaly

    The Structure of l-Phenyl-4,5-(l,2-D-glucofurano)imidazolidin-2-one

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    The crystal structure of Cl3Ht6N20 5 has been solved by direct methods. Crystal data are a -- 9.033 (1), b -- 10.097 (1), c -- 7.155 (1)A, fl= 105.92 (1) °, Z -- 2, space group P21 (from statistics). The final R value for 1246 independent reflexions was 0.068. The glucofurano- imidazolidine group adopts a cis form of coupling with a dihedral angle of 70.2 (6) °. The phenyl substituent forms a dihedral angle of 15.1 (6) ° with the imidazolidine ring plane. Intermolecular hydrogen bonds link molecules related by a screw axis to give helical chains parallel to b

    The Crystal Structure and Molecular Conformation of 3,7-Dichlorophenoselenazine

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    The crystal structure of SeC12NCI2H7 has been solved by Patterson and Fourier methods and refined to an R of 7-5 % by full-matrix least-squares methods. The unit cell is orthorhombic, with a-- 7-995 (3), b = 23.808 (1), c = 6.028 (2)/~, and four molecules in the cell. The space group is Pnma. The structure contains layers of molecules centred on the mirror planes at b/4 and 3b/4

    The crystal structure and molecular conformation of 3,7-dichlorophenoselenazine

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