2,554 research outputs found
The FUV to Near-IR Morphologies of Luminous Infrared Galaxies in the GOALS Sample
We compare the morphologies of a sample of 20 LIRGs from the Great
Observatories All-sky LIRG Survey (GOALS) in the FUV, B, I and H bands, using
the Gini (G) and M20 parameters to quantitatively estimate the distribution and
concentration of flux as a function of wavelength. HST images provide an
average spatial resolution of ~80 pc. While our LIRGs can be reliably
classified as mergers across the entire range of wavelengths studied here,
there is a clear shift toward more negative M20 (more bulge-dominated) and a
less significant decrease in G values at longer wavelengths. We find no
correlation between the derived FUV G-M20 parameters and the global measures of
the IR to FUV flux ratio, IRX. Given the fine resolution in our HST data, this
suggests either that the UV morphology and IRX are correlated on very small
scales, or that the regions emitting the bulk of the IR emission emit almost no
FUV light. We use our multi-wavelength data to simulate how merging LIRGs would
appear from z~0.5-3 in deep optical and near-infrared images such as the HUDF,
and use these simulations to measure the G-M20 at these redshifts. Our
simulations indicate a noticeable decrease in G, which flattens at z >= 2 by as
much as 40%, resulting in mis-classifying our LIRGs as disk-like, even in the
rest-frame FUV. The higher redshift values of M20 for the GOALS sources do not
appear to change more than about 10% from the values at z~0. The change in
G-M20 is caused by the surface brightness dimming of extended tidal features
and asymmetries, and also the decreased spatial resolution which reduced the
number of individual clumps identified. This effect, seen as early as z~0.5,
could easily lead to an underestimate of the number of merging galaxies at
high-redshift in the rest-frame FUV.Comment: Accepted for publication in the Astronomical Journal. The total page
count is 15 pages with 13 figures and 1 Tabl
The Future of the Railway Transportation from the Science Fiction Point of View
The main goal of the doctoral thesis from which this article arises, is the search, analysis, investigation and obtaining conclusions about the particular vision and proposals in the Science Fiction graphic novel of the 20th Century, related with the Civil Engineering and specially with one of its disciplines, the Transportation Engineering. In this paper we anticipate and summarize a brief sample of the doctoral thesis, including some of the most important aspects of the research and the conclusions obtained in the Railway chapter exclusively. After the work done we will conclude that there are countless references to the Transports and also to the Railway world in the Science Fiction comic. The vision of the graphic novelsâ authors about the role of the communication infrastructures in the structuring of the city, its space, its function, the physical placement of the viaducts, the morphology, use and source of energy of the vehicles: (ground, marine, air ones and others) ⊠are constantly reflected in their stories, and they deserve a deep technical, social and even philosophical analysis, that we will try to accomplish in the mentioned doctoral thesis and, partially, in this paper
Identification of Dominant Hydrological Mechanisms Using Bayesian Inference, Multiple Statistical Hypothesis Testing, and Flexible Models
ABSTARCT: In hydrological modeling, the identification of model mechanisms best suited for representing individual hydrological (physical) processes is of major scientific and operational interest. We present a statistical hypothesis-testing perspective on this model identification challenge and contribute a mechanism identification framework that combines: (i) Bayesian estimation of posterior probabilities of individual mechanisms from a given ensemble of model structures; (ii) a test statistic that defines a ?dominant? mechanism as a mechanism more probable than all its alternatives given observed data; and (iii) a flexible modeling framework to generate model structures using combinations of available mechanisms. The uncertainty in the test statistic is approximated using bootstrap sampling from the model ensemble. Synthetic experiments (with varying error magnitude and multiple replicates) and real data experiments are conducted using the hydrological modeling system FUSE (7 processes and 2?4 mechanisms per process yielding 624 feasible model structures) and data from the LeizarĂĄn catchment in northern Spain. The mechanism identification method is reliable: it identifies the correct mechanism as dominant in all synthetic trials where an identification is made. As data/model errors increase, statistical power (identifiability) decreases, manifesting as trials where no mechanism is identified as dominant. The real data case study results are broadly consistent with the synthetic analysis, with dominant mechanisms identified for 4 of 7 processes. Insights on which processes are most/least identifiable are also reported. The mechanism identification method is expected to contribute to broader community efforts on improving model identification and process representation in hydrology.The authors from IHCantabria acknowledge the financial support from the Government of Cantabria through the FĂNIX Program (ID 2020.03.03.322B.742.09)
The multiple meanings of ADHD: between deficit, disruption and hidden potential
The purpose of this article is to describe the subjective experience of the diagnosis of Attention Deficit and Hyperactivity Disorder (ADHD) and the cultural meanings that shape this experience. Based on interviews and discussion groups with diagnosed people and their families in Chile and France, this article show that ADHD can acquire multiple meanings. From a thematic analysis, we identified three registers or ways of living and thinking about ADHD. In the deficit register, the disorder is experienced primarily as a failure of certain abilities. In the disruption register, the disorder is experienced as disrupting the personâs life, personality and interactions, which must then be normalized. In the register of hidden potential, on which this article focuses, ADHD is simultaneously thought of as a difficult and valuable condition, a source of exceptional capacities that are often hidden in the ordinary functioning of social life. We therefore invite reflection that identifies the factors of mobilization or non-mobilization of the hidden potential register, with particular emphasis not only on relational configurations, socio-economic variables, and the gender variable, but also on the institutional and political context of each country
A photoionization model of the spatial distribution of the optical and mid-IR properties in NGC595
We present a set of photoionization models that reproduce simultaneously the
observed optical and mid-infrared spatial distribution of the HII region NGC595
in the disk of M33 using the code CLOUDY. Both optical (PMAS-Integral Field
Spectroscopy) and mid-infrared (8 mi and 24 mi bands from Spitzer) data provide
enough spatial resolution to model in a novel approach the inner structure of
the HII region. We define a set of elliptical annular regions around the
central ionizing cluster with an uniformity in their observed properties and
consider each annulus as an independent thin shell structure. For the first
time our models fit the relative surface brightness profiles in both the
optical (Halpha, [OII], [OIII]) and the mid-infrared emissions (8 mi and 24
mi), under the assumption of a uniform metallicity (12+log(O/H) = 8.45; Esteban
et al. 2009) and an age for the stellar cluster of 4.5 Myr (Malumuth et al.
1996). Our models also reproduce the observed uniformity of the R23 parameter
and the increase of the [OII]/[OIII] ratio due to the decrease of the
ionization parameter. The variation of the Halpha profile is explained in terms
of the differences of the occupied volume (the product of filling factor and
total volume of the shell) in a matter-bounded geometry, which also allows to
reproduce the observed pattern of the extinction. The 8 mi/24 mi ratio is low
(ranging between 0.04 and 0.4) because it is dominated by the surviving of
small dust grains in the HII region, while the PAHs emit more weakly because
they cannot be formed in these thin HII gas shells. The ratio is also well
fitted in our models by assuming a dust-to-gas ratio in each annulus compatible
with the integrated estimate for the whole HII region after the 70 mi, and 160
mi Spitzer observations.Comment: Accepted for publication in MNRAS, 9 pages, 17 figure
Hacia una hoja de ruta para el escalamiento de la AgroecologĂa en Colombia: un anĂĄlisis de las polĂticas, programas y factores limitantes actuales
El presente estudio nuestro objetivo es comprender los retos y las oportunidades que tiene la agroecologĂa para ser promovida desde las polĂticas pĂșblicas. En esta investigaciĂłn, propone una hoja de ruta que logre evidenciar las problemĂĄticas para lograr el escalamiento de la agroecologĂa desde diversos tipos factores. Esta propuesta de hoja de ruta tiene como objetivo ser un documento de base para generar diversos caminos para hacer escalar la agroecologĂa, desde la incidencia polĂtica a travĂ©s de los diversos sectores ministeriales, asĂ como en diversas escalas de gobierno (municipal, regional y nacional), de igual forma que pueda ser considerado por otros actores de la sociedad civil, productores y organizaciones de base
The Transportation Engineering Inside the City Structure in the Science Fiction Graphic Novel of the 20th Century
ABSTRACT:Abstract Comic books, graphic novels, bandes dessinĂ©es in France, Fumetti in Italy, Tebeos in Spain, etc, are only some of the names given to the ninth art in the world since their first representations in the Ancient Egypt times. In these last decades it has transformed itself, from just a children entertainment of little intellectual value, and now it belongs to the best family of universal literature. Just as the other arts, painting, music, poetry, cinemaâŠ, it has become another way of expression of the human being, who often reflects on his master pieces the compendium of the feelings and thoughts of a whole generation, an epoch, or even sublime states of the soul, capable to transmit, in just one masterpiece, the essence of our nature to the next generations. These artists, the comicâs ones, the same as in literature or cinema, have also tried to represent, not only the past and the present, but also the future of the human being. Doing sometimes prodigious imagination efforts, they have constructed utopic, distopic, extra-terrestrialâŠscenarios, designing realistic or impossible science fiction backgrounds, which will finally influence all of us, as intellectual beings that we are, in all our disciplines, just as the other arts do. And one of these disciplines is, of course, the science of transportation, in all its aspects. Willing to approach all these questions, we began a long investigation journey which will end in a doctoral thesis with the title: âThe Civil Engineering in the Science Fiction Graphic Novelâ. In this article we anticipate and summarize a small sample of our thesis, including some of the most important aspects of the mentioned investigation as well as the obtained conclusions
The Spatial Extent of (U)LIRGs in the mid-Infrared I: The Continuum Emission
We present an analysis of the extended mid-infrared (MIR) emission of the
Great Observatories All-Sky LIRG Survey (GOALS) sample based on 5-15um low
resolution spectra obtained with the IRS on Spitzer. We calculate the fraction
of extended emission as a function of wavelength for the galaxies in the
sample, FEE_lambda. We can identify 3 general types of FEE_lambda: one where it
is constant, one where features due to emission lines and PAHs appear more
extended than the continuum, and a third which is characteristic of sources
with deep silicate absorption at 9.7um. More than 30% of the galaxies have a
median FEE_lambda larger than 0.5 implying that at least half of their MIR
emission is extended. Luminous Infrared Galaxies (LIRGs) display a wide range
of FEE in their warm dust continuum (0<=FEE_13.2um<=0.85). The large values of
FEE_13.2um that we find in many LIRGs suggest that their extended MIR continuum
emission originates in scales up to 10kpc. The mean size of the LIRG cores at
13.2um is 2.6kpc. However, once the LIR of the systems reaches the threshold of
~10^11.8Lsun, all sources become clearly more compact, with FEE_13.2um<=0.2,
and their cores are unresolved. Our estimated upper limit for the core size of
ULIRGs is less than 1.5kpc. The analysis indicates that the compactness of
systems with LIR>~10^11.25Lsun strongly increases in those classified as
mergers in their final stage of interaction. The FEE_13.2um is also related to
the contribution of an active galactic nucleus (AGN) to the MIR. Galaxies which
are more AGN-dominated are less extended, independently of their LIR. We
finally find that the extent of the MIR continuum emission is correlated with
the far-IR IRAS log(f_60um/f_100um) color. This enables us to place a lower
limit to the area in a galaxy from where the cold dust emission may originate,
a prediction which can be tested soon with the Herschel Space Telescope.Comment: 18 pages, 8 figures, accepted for publication in Ap
Local Luminous Infrared Galaxies. I. Spatially resolved observations with Spitzer/IRS
We present results from the Spitzer/IRS spectral mapping observations of 15
local luminous infrared galaxies (LIRGs). In this paper we investigate the
spatial variations of the mid-IR emission which includes: fine structure lines,
molecular hydrogen lines, polycyclic aromatic features (PAHs), continuum
emission and the 9.7um silicate feature. We also compare the nuclear and
integrated spectra. We find that the star formation takes place in extended
regions (several kpc) as probed by the PAH emission as well as the [NeII] and
[NeIII] emissions. The behavior of the integrated PAH emission and 9.7um
silicate feature is similar to that of local starburst galaxies. We also find
that the minima of the [NeIII]/[NeII] ratio tends to be located at the nuclei
and its value is lower than that of HII regions in our LIRGs and nearby
galaxies. It is likely that increased densities in the nuclei of LIRGs are
responsible for the smaller nuclear [NeIII]/[NeII] ratios. This includes the
possibility that some of the most massive stars in the nuclei are still
embedded in ultracompact HII regions. In a large fraction of our sample the
11.3um PAH emission appears more extended than the dust 5.5um continuum
emission. We find a dependency of the 11.3um PAH/7.7 um PAH and [NeII]/11.3um
PAH ratios with the age of the stellar populations. Smaller and larger ratios
respectively indicate recent star formation. The estimated warm (300 K < T <
1000 K) molecular hydrogen masses are of the order of 10^8 M_Sun, which are
similar to those found in ULIRGs, local starbursts and Seyfert galaxies.
Finally we find that the [NeII] velocity fields for most of the LIRGs in our
sample are compatible with a rotating disk at ~kpc scales, and they are in a
good agreement with H-alpha velocity fields.Comment: Comments: 52 pages, accepted for publicacion in ApJ
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