2,756 research outputs found
Long slit spectroscopy of a sample of isolated spirals with and without an AGN
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
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 CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de FÃsica del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FÃsica del Plasma; ArgentinaFil: Kleiman, Ariel Javier. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de FÃsica del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FÃsica del Plasma; ArgentinaFil: Sequeda, F.. Universidad del Valle; ColombiaFil: Márquez, A.. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de FÃsica del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FÃsica 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
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
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
EconomÃa 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
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 Crystal Structure and Molecular Conformation of 3,7-Dichlorophenoselenazine
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 Structure of l-Phenyl-4,5-(l,2-D-glucofurano)imidazolidin-2-one
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
- …