10,504 research outputs found
Formación del profesorado en pedagogía intercultural: contenidos actitudinales
La inmigración es una realidad en las sociedades occidentales;
una situación que, aunque no es nueva, sí se manifiesta
con dimensiones no conocidas hasta ahora en nuestro país,
no sólo por su incremento cuantitativo sino por la variabilidad
detectada. Necesariamente esta nueva situación
afecta o puede afectar a la cohesión social. El problema es
multidimensional y sólo desde diferentes marcos coordinados
podremos ofrecer una “hospitalidad” por parte de nuestra
cultura mayoritaria, que no genere problemas de convivencia
y facilite la intercomunicación enriquecedora para
todos, basada en el respeto.
Para afrontar esta nueva situación no basta con el entusiasmo
voluntario del profesorado si no se acompaña de apoyos
institucionales y sociales, y por supuesto, de fondos económicos.
Sin embargo, tampoco es suficiente manifestar una
actitud positiva hacia el multiculturalismo, sin racionalizar
y sistematizar el trabajo a realizar
A search for new hot subdwarf stars by means of Virtual Observatory tools
Hot subdwarf stars are faint, blue objects, and are the main contributors to
the far-UV excess observed in elliptical galaxies. They offer an excellent
laboratory to study close and wide binary systems, and to scrutinize their
interiors through asteroseismology, as some of them undergo stellar
oscillations. However, their origins are still uncertain, and increasing the
number of detections is crucial to undertake statistical studies. In this work,
we aim at defining a strategy to find new, uncatalogued hot subdwarfs. Making
use of Virtual Observatory tools we thoroughly search stellar catalogues to
retrieve multi-colour photometry and astrometric information of a known sample
of blue objects, including hot subdwarfs, white dwarfs, cataclysmic variables
and main sequence OB stars. We define a procedure to discriminate among these
spectral classes, particularly designed to obtain a hot subdwarf sample with a
low contamination factor. In order to check the validity of the method, this
procedure is then applied to two test sky regions: the Kepler FoV and to a test
region of around (RA:225, DEC:5) deg. As a result, we obtained 38 hot subdwarf
candidates, 23 of which had already a spectral classification. We have acquired
spectroscopy for three other targets, and four additional ones have an
available SDSS spectrum, which we used to determine their spectral type. A
temperature estimate is provided for the candidates based on their spectral
energy distribution, considering two-atmospheres fit for objects with clear
infrared excess. Eventually, out of 30 candidates with spectral classification,
26 objects were confirmed to be hot subdwarfs, yielding a contamination factor
of only 13%. The high rate of success demonstrates the validity of the proposed
strategy to find new uncatalogued hot subdwarfs. An application of this method
to the entire sky will be presented in a forthcoming work.Comment: 13 pages, 7 figure
The complex structure of HH 110 as revealed from Integral Field Spectroscopy
HH 110 is a rather peculiar Herbig-Haro object in Orion that originates due
to the deflection of another jet (HH 270) by a dense molecular clump, instead
of being directly ejected from a young stellar object. Here we present new
results on the kinematics and physical conditions of HH 110 based on Integral
Field Spectroscopy. The 3D spectral data cover the whole outflow extent (~4.5
arcmin, ~0.6 pc at a distance of 460 pc) in the spectral range 6500-7000 \AA.
We built emission-line intensity maps of H, [NII] and [SII] and of
their radial velocity channels. Furthermore, we analysed the spatial
distribution of the excitation and electron density from [NII]/H,
[SII]/H, and [SII] 6716/6731 integrated line-ratio maps, as well as
their behaviour as a function of velocity, from line-ratio channel maps. Our
results fully reproduce the morphology and kinematics obtained from previous
imaging and long-slit data. In addition, the IFS data revealed, for the first
time, the complex spatial distribution of the physical conditions (excitation
and density) in the whole jet, and their behaviour as a function of the
kinematics. The results here derived give further support to the more recent
model simulations that involve deflection of a pulsed jet propagating in an
inhomogeneous ambient medium. The IFS data give richer information than that
provided by current model simulations or laboratory jet experiments. Hence,
they could provide valuable clues to constrain the space parameters in future
theoretical works.Comment: 12 pages, 15 figures Accepted in MNRA
Birth, death and diffusion of interacting particles
Individual-based models of chemical or biological dynamics usually consider
individual entities diffusing in space and performing a birth-death type
dynamics. In this work we study the properties of a model in this class where
the birth dynamics is mediated by the local, within a given distance, density
of particles. Groups of individuals are formed in the system and in this paper
we concentrate on the study of the properties of these clusters (lifetime,
size, and collective diffusion). In particular, in the limit of the interaction
distance approaching the system size, a unique cluster appears which helps to
understand and characterize the clustering dynamics of the model.Comment: 15 pages, 6 figures, Iop style. To appear in Journal of Physics A:
Condensed matte
A methodology to introduce sustainability into the Final Year Project to foster sustainable engineering projects
The introduction of sustainability skills into higher education curricula is a natural effect of the increasing importance of sustainability in our daily lives. Topics like green computing, sustainable design or environmental engineering have become part of the knowledge required by today’s engineers. Furthermore, we strongly believe that the introduction of this skill will eventually enable future engineers to develop sustainable products, services and projects. The Final Year Project is the last academic stage facing students and a step towards their future professional engineering projects. As such, it constitutes a rehearsal for their professional future and an ideal opportunity for reflecting on whether their Final Year Project is sustainable or not, and to what extent. It also provides a good tool for reviewing the lessons learned about sustainability during the degree course and for applying them in a holistic and integrated way. In this paper, we present a guide that allows both students and advisors to think carefully about the sustainability of engineering projects, in particular the Final Year Project.Postprint (author’s final draft
Structural analysis and sintering aids effects in La2Ce2O7 proton conductors
Global warming is an important problem that has to be solved without delay. The development of environmental-friendly energy technology is needed to deal with this issue. Solid Oxide Fuel Cells (SOFC) technology has been proposed as a real alternative to fossil fuel combustion. Proton conductors like La2Ce2O7 (LDC), has several advantages in comparison with BaCeO3 due to its high stability in H2O or CO2 conditions [1]. Furthermore, for industry application is necessary to low the high sintering temperature of typical electrolyte materials.
La2Ce2O7 was synthesized by the freeze-drying precursor method and calcination conditions have been optimized to obtain single phase with high compaction at 1400 ºC for 1h. A fully characterization has been carried out using X-ray powder diffraction and scanning electron microscopy. The total conductivity was determined by complex impedance spectroscopy in dry and wet air. Transmission Electron Microscopy (TEM) was used to clarify certainly the structure of La2Ce2O7 due to its still unknown. SAEDs patterns revealed a disordered fluorite, not appearing secondary reflections typical of pyrochlore superstructure, finishing the controversy around the correct structure in this material [2,3].
Moreover, an exhaustive study about lowering the sintering temperature with Co and Zn as sintering aids has been investigated obtaining electrolytes that can be used for SOFC. The sintering aids were impregnated using cobalt and zinc nitrates in ethanol media. Both sintering aids allow for obtain high dense pellets lowering the sintering temperature 300 ºC and 400 ºC for samples with cobalt and zinc, respectively, without compromising the electrical and microstructural properties (Fig 1).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Integral Field Spectroscopy of HH 262: The Spectral Atlas
HH 262 is a group of emitting knots displaying an "hour-glass" morphology in
the Halpha and [SII] lines, located 3.5' to the northeast of the young stellar
object L1551-IRS5, in Taurus. We present new results of the kinematics and
physical conditions of HH 262 based on Integral Field Spectroscopy covering a
field of 1.5'x3', which includes all the bright knots in HH 262. These data
show complex kinematics and significant variations in physical conditions over
the mapped region of HH 262 on a spatial scale of <3". A new result derived
from the IFS data is the weakness of the [NII] emission (below detection limit
in most of the mapped region of HH 262), including the brightest central knots.
Our data reinforce the association of HH 262 with the redshifted lobe of the
evolved molecular outflow L1551-IRS5. The interaction of this outflow with a
younger one, powered by L1551 NE, around the position of HH 262 could give rise
to the complex morphology and kinematics of HH 262.Comment: Accepted for publication in MNRA
Deep into the Water Fountains: The case of IRAS 18043-2116
(Abridged) The formation of large-scale (hundreds to few thousands of AU)
bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic
Giant Branch (post-AGB) stars is poorly understood. The shape of these
structures, traced by emission from fast molecular outflows, suggests that the
dynamics at the innermost regions of these CSEs does not depend only on the
energy of the radiation field of the central star. Deep into the Water
Fountains is an observational project based on the results of programs carried
out with three telescope facilities: The Karl G. Jansky Very Large Array
(JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large
Telescope (SINFONI-VLT). Here we report the results of the observations towards
the WF nebula IRAS 180432116: Detection of radio continuum emission in the
frequency range 1.5GHz - 8.0GHz; HO maser spectral features and radio
continuum emission detected at 22GHz, and H ro-vibrational emission lines
detected at the near infrared. The high-velocity HO maser spectral
features, and the shock-excited H emission detected could be produced in
molecular layers which are swept up as a consequence of the propagation of a
jet-driven wind. Using the derived H column density, we estimated a
molecular mass-loss rate of the order of Myr. On the
other hand, if the radio continuum flux detected is generated as a consequence
of the propagation of a thermal radio jet, the mass-loss rate associated to the
outflowing ionized material is of the order of 10Myr.
The presence of a rotating disk could be a plausible explanation for the
mass-loss rates estimated.Comment: 10 pages, 5 figures. Accepted for publication in A&
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