5,292 research outputs found
Masgomas-4: Physical characterization of a double-core obscured cluster with a massive and very young stellar population
The discovery of new, obscured massive star clusters has changed our
understanding of the Milky Way star-forming activity from a passive to a very
active star-forming machine. The search for these obscured clusters is strongly
supported by the use of all-sky, near-IR surveys.
The main goal of the MASGOMAS project is to search for and study unknown,
young, and massive star clusters in the Milky Way, using near-IR data. Here we
try to determine the main physical parameters (distance, size, total mass, and
age) of Masgomas-4, a new double-core obscured cluster.
Using near-IR photometry (, , and ) we selected a total of 21
stars as OB-type star candidates. Multi-object, near-IR follow-up spectroscopy
allowed us to carry out the spectral classification of the OB-type candidates.
Of the 21 spectroscopically observed stars, ten are classified as OB-type
stars, eight as F- to early G-type dwarf stars, and three as late-type giant
stars. Spectroscopically estimated distances indicate that the OB-type stars
belong to the same cluster, located at a distance of
kpc. Our spectrophotometric data confirm a very young and massive stellar
population, with a clear concentration of pre-main-sequence massive candidates
(Herbig Ae/Be) around one of the cluster cores. The presence of a surrounding
HII cloud and the Herbig Ae/Be candidates indicate an upper age limit of 5 Myr.Comment: Accepted for publication in A&
Thermal diagnostic of the Optical Window on board LISA Pathfinder
Vacuum conditions inside the LTP Gravitational Reference Sensor must comply
with rather demanding requirements. The Optical Window (OW) is an interface
which seals the vacuum enclosure and, at the same time, lets the laser beam go
through for interferometric Metrology with the test masses. The OW is a
plane-parallel plate clamped in a Titanium flange, and is considerably
sensitive to thermal and stress fluctuations. It is critical for the required
precision measurements, hence its temperature will be carefully monitored in
flight. This paper reports on the results of a series of OW characterisation
laboratory runs, intended to study its response to selected thermal signals, as
well as their fit to numerical models, and the meaning of the latter. We find
that a single pole ARMA transfer function provides a consistent approximation
to the OW response to thermal excitations, and derive a relationship with the
physical processes taking place in the OW. We also show how system noise
reduction can be accomplished by means of that transfer function.Comment: 20 pages, 14 figures; accepted for publication in Class. Quantum Gra
Discrete breathers in dissipative lattices
We study the properties of discrete breathers, also known as intrinsic
localized modes, in the one-dimensional Frenkel-Kontorova lattice of
oscillators subject to damping and external force. The system is studied in the
whole range of values of the coupling parameter, from C=0 (uncoupled limit) up
to values close to the continuum limit (forced and damped sine-Gordon model).
As this parameter is varied, the existence of different bifurcations is
investigated numerically. Using Floquet spectral analysis, we give a complete
characterization of the most relevant bifurcations, and we find (spatial)
symmetry-breaking bifurcations which are linked to breather mobility, just as
it was found in Hamiltonian systems by other authors. In this way moving
breathers are shown to exist even at remarkably high levels of discreteness. We
study mobile breathers and characterize them in terms of the phonon radiation
they emit, which explains successfully the way in which they interact. For
instance, it is possible to form ``bound states'' of moving breathers, through
the interaction of their phonon tails. Over all, both stationary and moving
breathers are found to be generic localized states over large values of ,
and they are shown to be robust against low temperature fluctuations.Comment: To be published in Physical Review
Validez de una Competencia Docente con Enfoque Inclusivo en el Ámbito Universitario
El presente artículo muestra resultados preliminares de una investigación más amplia de la Universidad Autónoma de Chihuahua, relacionada con seis competencias docentes que permite al catedrático universitario dar una respuesta oportuna al proceso de inclusión educativa, se desarrolló la validez del modelo de competencias docentes basadas en “Coordina la interacción pedagógica inclusiva“ y “Gestiona la progresión de los aprendizajes“ pertenecientes a una investigación más amplia de 10 competencias. Se validó el modelo propuesto por medio de la metodología Delphi, con la medición de univocidad, y pertinencia; se consolido a través del Análisis Factorial Exploratorio y Confirmatorio. La competencia tiene como propósito una docencia basada en situaciones reales que implica las formas de interacción incluyente con base a una relación educativa sustentada en la comunicación horizontal y generación de ambientes de aprendizajes con el fin de promover redes de colaboración. En el primer proceso se obtiene más de .90 en cada valor presentado en univocidad y pertinencia; bajo el Análisis Factorial Confirmatorio se agrupan en una sola competencia con los indicadores que muestra el referencial óptimo (GFI .849) y superior al valor (RMSEA .083) con las medidas de ajuste incremental y de parsimonia, superior al modelo independiente, en conclusión, es válida y confiable para el apoyo de la intervención universitaria en poblaciones con discapacidad.
This paper focuses on the initial results of a broader Autonomous University of Chihuahua research, which is related to six teaching competencies that allow the university professor to provide timely response to the process of educational inclusion. It was developed with the validity of the educational competencies model based on “Coordinating the inclusive educational interaction” and “Managing the improvement in learning” which belongs to a broader research of 10 competencies. The model was proposed through Delphi methodology and validated through nonduality measuring and relevance. It was consolidated through Exploratory Factorial and Validating Analysis. The competency has a purpose of teaching based on real situations that involves the ways of inclusive interaction. This is done on the basis of an educational relationship that is backed up in horizontal communication and generation of learning environments in order to promote collaboration networks. In the first process, more than 0.90 was obtained in each submitted value for nonduality and relevance. Under the Validating Factorial Analysis, they were grouped together under one competency. The indicators, thus, showed the optimal referencial (GFI 0.849) and the value (RMSEA 0.083) through the measurements of incremental and parsimony adjustment, which is above the independent model. This means that it is valid and reliable for supporting university intervention in disabled populations
SUBARU and e-Merlin observations of NGC3718. Diaries of an SMBH recoil?
NGC3718 is a LINER galaxy, lying at a distance of about
Mpc away from earth and its similarities with NGC5128 often award it the name
"northern Centaurus A". We use high angular resolution ( mas) e-Merlin
radio and SUBARU NIR ( mas) data, to take a detailed view of the
processes taking place in its central region. In order to preserve some
objectivity in our interpretation, we combine our results with literature
values and findings from previous studies. Our NIR maps suggest, on one hand,
that towards the stellar bulge there are no large scale absorption phenomena
caused by the apparent dust lane and, on the other, that there is a significant
(local) contribution from hot ( K) dust to the nuclear NIR emission.
The position where this takes place appears to be closer to the offset compact
radio emission from our e-Merlin cm map, lying offset by pc from
the center of the underlying stellar bulge. The shape of the radio map suggests
the presence of one (or possibly two, forming an X-shape) bipolar structure(s)
() arcsec across, which combined with the balance between the
gas and the stellar velocity dispersions and the presence of hard X-ray
emission, point towards effects expected by AGN feedback. We also argue that
NGC3718 has a "core" in its surface brightness profile, despite the fact that
it is a gas-rich galaxy and we discuss its mixed photometric and spectroscopic
characteristics. The latter combined with the observed spatial and radio
offsets, the relative redshift between the broad and the narrow
line, the limited star formation activity and AGN
feedback, strongly imply the existence of an SMBH recoil. Finally, we discuss a
possible interpretation, that could naturally incorporate all these findings
into one physically consistent picture.Comment: 18 pages, 18 figures, 3 tables, accepted for publications in A&
Stable isotopes reveal differences in diet among reed bunting subspecies that vary in bill size
Reed bunting Emberiza schoeniclus subspecies vary considerably in bill size and shape and seem to be at an early stage of speciation, in which bill might be indirectly causing reproductive isolation. Hence, we evaluated whether bill size, as well as age and sex, are associated with foraging niche in three west European subspecies of reed bunting: the thin-billed schoeniclus, the intermediate-billed lusitanica and the thick-billed witherbyi. Blood sampling was undertaken at three sites in southwest Europe during the winter (when these subspecies co-occur), and stable isotope analyses (carbon and nitrogen) were performed to assess their foraging niches. Stable isotope analyses of potential food items confirmed uniform baseline isotopic composition among sites. schoeniclus showed a significantly broader isotopic niche than lusitanica and witherbyi, which seemed otherwise similar despite the fact that witherbyi is more divergent in bill traits. Stable isotope ratios were consistent with the latter two subspecies feeding on C3-plant-feeding insects, whereas schoeniclus diet also included C4 plant material. Despite its lower sexual dimorphism, sex and age differences were found only in schoeniclus, but these differences vary between locations in a complex manner. Our results suggest that bill size and shape differentiated between northern, migratory and southern, resident subspecies as a consequence of natural selection through competition during the winter, which is now reflected in isotopic niche divergence between subspecies. The potential roles of sexual selection, reed thickness and summer temperature on the difference in bill size (and greater sexual dimorphism) between lusitanica and witherbyi are discussed
The right to gender recognition before the Colombian constitutional court: a queer and travesti theory analysis
This article discusses the case-law on gender recognition of the ColombianConstitutional Court. It argues that the Court, paying attention to queerand trans theory and to the demands of trans activists, has interpretedmainstream constitutional rights in such a way that trans people can havetheir self-defined identities recognised. The article criticises the limitationsof this case-law, which still does not explicitly include non-binary andgender fluid people. On the other hand, it highlights that the Court’s doc-trine has the potential to challenge both the gender binary and the verycategory of ‘sex’ or ‘gender’ in the law
Integral field optical spectroscopy of a representative sample of ULIRGs: II. Two-dimensional kpc-scale extinction structure
We investigate the two-dimensional kpc-scale structure of the extinction in a
representative sample of local ULIRGs using the Halpha/Hbeta line ratio.We use
optical integral field spectroscopy obtained with the INTEGRAL instrument at
the William Herschel Telescope. Complementary optical and near-IR high angular
resolution HST images have also been used. The extinction exhibits a very
complex and patchy structure in ULIRGs on kpc scales, from basically
transparent regions to others deeply embedded in dust (Av~0.0 to Av~8.0 mag).
Nuclear extinction covers a broad range in Av from 0.6 to 6 mag, 69% of the
nuclei having Av>2.0 mag. Extinction in the external regions is substantially
lower than in the nuclei with 64% of the ULIRGs in the sample having median Av
of less than 2 mag for the entire galaxy. While post-coalescence nuclei tend to
cluster around Av values of 2 to 3 mag, pre-coalescence nuclei appear more
homogeneously distributed over the entire 0.4 mag <Av< 7.7 mag range. For the
average extinction (Av~2.0 derived for the ULIRGs of the sample, the ratio of
the de-reddened to observed SFR values is 6. The extinction-corrected,
Halpha-based SFR ranges from 10 to 300 Msun/yr. For only 28% of the cases the
de-reddened SFR is <20 Msun/yr, whereas for the observed SFR this percentage
increases to 72%. The IR-based SFR is always higher than the optical-based one,
with differences ranging from about 2 to up to 30. The nuclear observed SFR has
an average contribution to the total one of 16% for the entire sample. Once
corrected for extinction, the average value becomes 31%. Because of mostly
extinction effects, the optical (I-band) half-light radius in the sample
galaxies is on average a factor 2.3 larger than the corresponding near-IR
(H-band) value.Comment: To appear in A&
A Wildfire Prediction Based on Fuzzy Inference System for Wireless Sensor Networks
The study of forest fires has been traditionally considered as an important
application due to the inherent danger that this entails. This phenomenon
takes place in hostile regions of difficult access and large areas. Introduction of
new technologies such as Wireless Sensor Networks (WSNs) has allowed us to
monitor such areas. In this paper, an intelligent system for fire prediction based
on wireless sensor networks is presented. This system obtains the probability of
fire and fire behavior in a particular area. This information allows firefighters to
obtain escape paths and determine strategies to fight the fire. A firefighter can
access this information with a portable device on every node of the network. The
system has been evaluated by simulation analysis and its implementation is being
done in a real environment.Junta de Andalucía P07-TIC-02476Junta de Andalucía TIC-570
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