74 research outputs found
Didáctica de las Actividades en el medio natural mediante m-learning y realidad aumentada en el Grado de Magisterio en Educación Primaria
En este trabajo se presenta la fase de evaluación de un proyecto de innovación didáctica llevado a cabo en el Grado de Magisterio en Educación Primaria (Universidad de Zaragoza). El proyecto se fundamenta en la incorporación del m-learning y de la realidad aumentada como metodología de la enseñanza de contenidos de actividades en el medio natural. Los contenidos sobre los que se ha trabajado son la bicicleta todo terreno, la escalada, la orientación, el senderismo, el esquí y el trail. El alumnado participante, que es futuro maestro de Educación Física, valora positivamente este método de trabajo, destacando la motivación que supone a nivel pedagógico. Del mismo modo, encuentra ciertas limitaciones, como la disponibilidad del número de dispositivos móviles o la necesidad de estar conectados a la red para poder utilizar determinadas aplicaciones. This paper presents the evaluation phase of a didactic innovation project. It has been developed in the Teaching in Primary Education degree (University of Zaragoza). The project shows the m-learning and augmented reality as a teaching methodology for outdoor activities contents. The contents on which we have worked are mountain biking, climbing, orientation, hiking, skiing and trail running. The students, future Physical Education teachers, valued positively this method. They underlined the motivation aroused in the students due to the novelty like a pedagogical way to work. In the same way, they found certain limitations. Firstly, the availability of the number of mobile devices needed. Secondly, the need to be connected to the network in order to use certain applications
Testing models with non-minimal Higgs sector through the decay t->q+WZ
We study the contribution of charged Higgs boson to the rare decay of the top
quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and
triplets. Higgs doublets are needed to couple charged Higgs with quarks,
whereas the Higgs triplets are required to generate the non-standard vertex HWZ
at tree-level. It is found that within a model that respect the custodial SU(2)
symmetry and avoids flavour changing neutral currents by imposing discrete
symmetries, the decay mode t->b+WZ, can reach a branching ratio of order
0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching
ratio in models where flavour changing neutral currents are suppressed by
flavour symmetries.Comment: Typeset using REVTEX and EPSF, 5 pag, 2 figure
Central star formation and metallicity in CALIFA interacting galaxies
We use optical integral-field spectroscopic (IFS) data from 103 nearby
galaxies at different stages of the merging event, from close pairs to merger
remnants provided by the CALIFA survey, to study the impact of the interaction
in the specific star formation and oxygen abundance on different galactic
scales. To disentangle the effect of the interaction and merger from internal
processes, we compared our results with a control sample of 80 non-interacting
galaxies. We confirm the moderate enhancement (2-3 times) of specific star
formation for interacting galaxies in central regions as reported by previous
studies; however, the specific star formation is comparable when observed in
extended regions. We find that control and interacting star-forming galaxies
have similar oxygen abundances in their central regions, when normalized to
their stellar masses. Oxygen abundances of these interacting galaxies seem to
decrease compared to the control objects at the large aperture sizes measured
in effective radius. Although the enhancement in central star formation and
lower metallicities for interacting galaxies have been attributed to tidally
induced inflows, our results suggest that other processes such as stellar
feedback can contribute to the metal enrichment in interacting galaxies.Comment: 9 pages, 9 figures. Accepted for publication in Astronomy &
Astrophysic
Ionized gas kinematics of galaxies in the CALIFA survey : I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems
J.M.A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). Date of Acceptance: 01/08/2014Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims. The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [O ii] λλ3726,3729, [O iii] λλ4959,5007, Hα+[N ii] λλ6548,6584, and [SII]λλ6716,6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [O iii] λλ4959,5007 emission line profiles. Results. At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear photometric-kinematic misaligments. There is evidence of asymmetries in the emission line profiles in 117 out of the 177 analyzed galaxies, suggesting the presence of kinematically distinct gaseous components located at different distances from the optical nucleus. The kinematic decoupling between the dominant and secondary component/s suggested by the observed asymmetries in the profiles can be characterized by a limited set of parameters. Conclusions. This work constitutes the first determination of the ionized gas kinematics of the galaxies observed in the CALIFA survey. The derived velocity fields, the reported kinematic distortions/peculiarities and the identification of the presence of several gaseous components in different regions of the objects might be used as additional criteria for selecting galaxies for specific studies.Publisher PDFPeer reviewe
VMD description of decays and the mixing angle
Using the vector meson dominance model we get predictions for the
Cabibbo-favored \tom and \tphi decays. We show how the measurements of
these two decays can provide information on the nature of the violation of the
OZI rule.Comment: A misprint in Eqs. (14) has been correcte
The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and Te-based literature data
The use of IFS is since recently allowing to measure the emission line fluxes
of an increasingly large number of star-forming galaxies both locally and at
high redshift. The main goal of this study is to review the most widely used
empirical oxygen calibrations, O3N2 and N2, by using new direct abundance
measurements. We pay special attention to the expected uncertainty of these
calibrations as a function of the index value or abundance derived and the
presence of possible systematic offsets. This is possible thanks to the
analysis of the most ambitious compilation of Te-based HII regions to date.
This new dataset compiles the Te-based abundances of 603 HII regions extracted
from the literature but also includes new measurements from the CALIFA survey.
Besides providing new and improved empirical calibrations for the gas
abundance, we also present here a comparison between our revisited calibrations
with a total of 3423 additional CALIFA HII complexes with abundances derived
using the ONS calibration by Pilyugin et al. (2010). The combined analysis of
Te-based and ONS abundances allows us to derive their most accurate calibration
to date for both the O3N2 and N2 single-ratio indicators, in terms of all
statistical significance, quality and coverage of the space of parameters. In
particular, we infer that these indicators show shallower abundance
dependencies and statistically-significant offsets compared to those of Pettini
and Pagel (2004), Nagao et al. (2006) and P\'erez-Montero and Contini (2009).
The O3N2 and N2 indicators can be empirically applied to derive oxygen
abundances calibrations from either direct abundance determinations with random
errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a
large amount of data) reaching an average precision of 0.08 and 0.09 dex
(random) and 0.02 and 0.08 dex (systematic; compared to the direct
estimations),respectively.Comment: 12 pages, 5 figures, accepted for publication in A&
The intrinsic shape of galaxy bulges
The knowledge of the intrinsic three-dimensional (3D) structure of galaxy
components provides crucial information about the physical processes driving
their formation and evolution. In this paper I discuss the main developments
and results in the quest to better understand the 3D shape of galaxy bulges. I
start by establishing the basic geometrical description of the problem. Our
understanding of the intrinsic shape of elliptical galaxies and galaxy discs is
then presented in a historical context, in order to place the role that the 3D
structure of bulges play in the broader picture of galaxy evolution. Our
current view on the 3D shape of the Milky Way bulge and future prospects in the
field are also depicted.Comment: Invited Review to appear in "Galactic Bulges" Editors: Laurikainen
E., Peletier R., Gadotti D. Springer Publishing. 24 pages, 7 figure
Melatonin Induces Follicle Maturation in Danio rerio
Most organisms modulate their reproductive activity responding to day length by the nocturnal release of melatonin by the pineal gland. This hormone is also responsible for synchronizing reproduction with specific external environment stimuli in order to optimize reproductive success
Aperture corrections for disk galaxy properties derived from the CALIFA survey. Balmer emission lines in spiral galaxies
This work investigates the effect of the aperture size on derived galaxy
properties for which we have spatially-resolved optical spectra. We focus on
some indicators of star formation activity and dust attenuation for spiral
galaxies that have been widely used in previous work on galaxy evolution. We
have used 104 spiral galaxies from the CALIFA survey for which 2D spectroscopy
with complete spatial coverage is available. From the 3D cubes we have derived
growth curves of the most conspicuous Balmer emission lines (Halpha, Hbeta) for
circular apertures of different radii centered at the galaxy's nucleus after
removing the underlying stellar continuum. We find that the Halpha flux
(f(Halpha)) growth curve follows a well defined sequence with aperture radius
showing low dispersion around the median value. From this analysis, we derive
aperture corrections for galaxies in different magnitude and redshift
intervals. Once stellar absorption is properly accounted for, the
f(Halpha)/f(Hbeta) ratio growth curve shows a smooth decline, pointing towards
the absence of differential dust attenuation as a function of radius. Aperture
corrections as a function of the radius are provided in the interval
[0.3,2.5]R_50. Finally, the Halpha equivalent width (EW(Halpha)) growth curve
increases with the size of the aperture and shows a very large dispersion for
small apertures. This large dispersion prevents the use of reliable aperture
corrections for this quantity. In addition, this result suggests that
separating star-forming and quiescent galaxies based on observed EW(Halpha)
through small apertures is likely to result in low EW(Halpha) star-forming
galaxies begin classified as quiescent.Comment: 5 pages, 3 figures, accepted for publication in Astronomy &
Astrophysics Letter
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