1,801 research outputs found
Urban sprawl and citizen participation. A case study in the municipality of La Pobla de Vallbona (Valencia)
[EN] The accelerated urban growth of the last decades in Europe has caused, especially in the Spanish Mediterranean coast, a paradigm shift in much cities, moving from a mostly compact urban form to a more diffuse one. The concept of city has changed so much that even in a lot of dispersed municipalities, it becomes difficult to define its limits. This change implies not only ecological and economic impacts, but also, social effects. Urban sprawl makes difficult social interaction and reduces the community feeling, and therefore, social cohesion and identity. This produces also changes in the relations of citizens between them and with the city council. The research propounds a discussion about the challenges that the urban sprawl causes for the application of participative models in the decision making, understanding them as basic criterion of good government. We analyze a case study to extract the complexity of articulating processes of citizen participation in territory with high dispersion based on a project carried out in the municipality of La Pobla de Vallbona (Valencia) on participatory budgets. It analyzes the results of the process carried out in relation to the urban model, the morphology of their urban pieces and spatial structure, and the demographic and social characteristics of the municipality. The question is identifying the problematic for the articulation of participative processes in territories with this idiosyncrasy. Finally, the article suggests a series of strategic lines as starting points to achieve participatory processes in the city characterized by urban sprawl.Gielen, E.; Pérez Alonso, Y.; Palencia Jiménez, JS.; Sosa Espinosa, A. (2018). Urban sprawl and citizen participation. A case study in the municipality of La Pobla de Vallbona (Valencia). En 24th ISUF International Conference. Book of Papers. Editorial Universitat Politècnica de València. 443-452. https://doi.org/10.4995/ISUF2017.2017.6154OCS44345
Self-organization of ultrasound in viscous fluids
We report the theoretical and experimental demonstration of pattern formation
in acoustics. The system is an acoustic resonator containing a viscous fluid.
When the system is driven by an external periodic force, the ultrasonic field
inside the cavity experiences different pattern-forming instabilities leading
to the emergence of periodic structures. The system is also shown to possess
bistable regimes, in which localized states of the ultrasonic field develop.
The thermal nonlinearity in the viscous fluid, together with the
far-from-equilibrium conditions, are is the responsible of the observed
effects
Análisis estructural 3D de los invernaderos multitunel del sudeste de España. Elementos verticales
Este trabajo analiza la capacidad estructural de los elementos verticales que componen el pórtico resistente más limitativo de la variante de invernadero multitúnel más utilizada en el sudeste de España. Se estudia la influencia de la longitud y anchura del invernadero en la distribución de tensiones que se produce en dichos elementos. Se ha realizado un modelo tridimensional de elementos finitos con el programa ROBOT MILLENNIUM en su versión 20.1 en el que se ha representado la estructura de barras que conforma el invernadero. Se han analizado los resultados de tensiones normales máximas de 16 estructuras con geometría de túnel similar, pero de diferente anchura y longitud, de tal forma que la superficie en planta oscila entre los 600 m 2 y los 38.400 m 2 . El cálculo de las acciones existentes sobre los invernaderos se ha realizado según la norma UNE-EN 13031-1. Los resultados numéricos obtenidos han sido estudiados para determinar la influencia de las dimensiones del invernadero en la distribución de tensiones. Aunque se observan significativas reducciones en las tensiones con la adición de túneles, no se puede generalizar la influencia del aumento de las dimensiones del invernadero en los cambios tensionales del mismo. Los resultados obtenidos se consideran de gran utilidad para la optimización de las estructuras de los invernaderos multitúnel así como para garantizar la seguridad mecánica de las misma
Characterization of AGN and their hosts in the Extended Groth Strip: a multiwavelength analysis
We have employed a reliable technique of classification of Active Galactic
Nuclei (AGN) based on the fit of well-sampled spectral energy distributions
(SEDs) with a complete set of AGN and starburst galaxy templates. We have
compiled ultraviolet, optical, and infrared data for a sample of 116 AGN
originally selected for their X-ray and mid-infrared emissions (96 with single
detections and 20 with double optical counterparts). This is the most complete
compilation of multiwavelength data for such a big sample of AGN in the
Extended Groth Strip (EGS). Through these SEDs, we are able to obtain highly
reliable photometric redshifts and to distinguish between pure and
host-dominated AGN. For the objects with unique detection we find that they can
be separated into five main groups, namely: Starburst-dominated AGN (24 % of
the sample), Starburst-contaminated AGN (7 %), Type-1 AGN (21 %), Type-2 AGN
(24 %), and Normal galaxy hosting AGN (24 %). We find these groups concentrated
at different redshifts: Type-2 AGN and Normal galaxy hosting AGN are
concentrated at low redshifts, whereas Starburst-dominated AGN and Type-1 AGN
show a larger span. Correlations between hard/soft X-ray and ultraviolet,
optical and infrared luminosities, respectively, are reported for the first
time for such a sample of AGN spanning a wide range of redshifts. For the 20
objects with double detection the percentage of Starburst-dominated AGN
increases up to 48%.Comment: 38 pages, 8 figures, 5 tables. Accepted by A
Testing the Unification Model for AGN in the Infrared: are the obscuring tori of Type 1 and 2 Seyferts different?
We present new mid-infrared (MIR) imaging data for three Type-1 Seyfert
galaxies obtained with T-ReCS on the Gemini-South Telescope at subarcsecond
resolution. Our aim is to enlarge the sample studied in a previous work to
compare the properties of Type-1 and Type-2 Seyfert tori using clumpy torus
models and a Bayesian approach to fit the infrared nuclear spectral energy
distributions (SEDs). Thus, the sample considered here comprises 7 Type-1, 11
Type-2, and 3 intermediate-type Seyferts. The unresolved IR emission of the
Seyfert 1 galaxies can be reproduced by a combination of dust heated by the
central engine and direct AGN emission, while for the Seyfert 2 nuclei only
dust emission is considered. These dusty tori have physical sizes smaller than
6 pc radius, as derived from our fits. Unification schemes of AGN account for a
variety of observational differences in terms of viewing geometry. However, we
find evidence that strong unification may not hold, and that the immediate
dusty surroundings of Type-1 and Type-2 Seyfert nuclei are intrinsically
different. The Type-2 tori studied here are broader, have more clumps, and
these clumps have lower optical depths than those of Type-1 tori. The larger
the covering factor of the torus, the smaller the probability of having direct
view of the AGN, and vice-versa. In our sample, Seyfert 2 tori have larger
covering factors and smaller escape probabilities than those of Seyfert 1. All
the previous differences are significant according to the Kullback-Leibler
divergence. Thus, on the basis of the results presented here, the
classification of a Seyfert galaxy as a Type-1 or Type-2 depends more on the
intrinsic properties of the torus rather than on its mere inclination towards
us, in contradiction with the simplest unification model.Comment: 21 pages, 14 figures, Appendix including supplementary figures.
Accepted by Ap
Torus and AGN properties of nearby Seyfert galaxies: Results from fitting IR spectral energy distributions and spectroscopy
We used the CLUMPY torus models and a Bayesian approach to fit the infrared
spectral energy distributions (SEDs) and ground-based high-angular resolution
mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put
tight constraints on torus model parameters such as the viewing angle, the
radial thickness of the torus Y, the angular size of the cloud distribution
sigma_torus, and the average number of clouds along radial equatorial rays N_0.
The viewing angle is not the only parameter controlling the classification of a
galaxy into a type 1 or a type 2. In principle type 2s could be viewed at any
viewing angle as long as there is one cloud along the line of sight. A more
relevant quantity for clumpy media is the probability for an AGN photon to
escape unabsorbed. In our sample, type 1s have relatively high escape
probabilities, while in type 2s, as expected, tend to be low. Our fits also
confirmed that the tori of Seyfert galaxies are compact with torus model radii
in the range 1-6pc. The scaling of the models to the data also provided the AGN
bolometric luminosities, which were found to be in good agreement with
estimates from the literature. When we combined our sample of Seyfert galaxies
with a sample of PG quasars from the literature to span a range of
L_bol(AGN)~10^{43}-10^{47}erg/s, we found plausible evidence of the receding
torus. That is, there is a tendency for the torus geometrical covering factor
to be lower at high AGN luminosities than at low AGN luminosities. This is
because at low AGN luminosities the tori appear to have wider angular sizes and
more clouds along radial equatorial rays. We cannot, however rule out the
possibility that this is due to contamination by extended dust structures not
associated with the dusty torus at low AGN luminosities, since most of these in
our sample are hosted in highly inclined galaxies. (Abridged)Comment: Accepted for publication in Ap
Shards: An optical spectro-photometric survey of distant galaxies
Pérez-González et al.We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin2 at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R ∿ 50). The data reach an AB magnitude of 26.5 (at least at a 3σ level) with sub-arcsec seeing in all bands. SHARDS' main goal is to obtain accurate physical properties of intermediate- and high-z galaxies using well-sampled optical spectral energy distributions (SEDs) with sufficient spectral resolution to measure absorption and emission features, whose analysis will provide reliable stellar population and active galactic nucleus (AGN) parameters. Among the different populations of high-z galaxies, SHARDS' principal targets are massive quiescent galaxies at z > 1, whose existence is one of the major challenges facing current hierarchical models of galaxy formation. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures which should be applied to the GTC/OSIRIS data. An assessment of the SHARDS data quality is also performed. We present science demonstration results on the detection and study of emission-line galaxies (star-forming objects and AGNs) at z = 0-5. We also analyze the SEDs for a sample of 27 quiescent massive galaxies with spectroscopic redshifts in the range 1.0 < z ≲ 1.4. We discuss the improvements introduced by the SHARDS data set in the analysis of their star formation history and stellar properties. We discuss the systematics arising from the use of different stellar population libraries, typical in this kind of study. Averaging the results from the different libraries, we find that the UV-to-MIR SEDs of the massive quiescent galaxies at z = 1.0-1.4 are well described by an exponentially decaying star formation history with scale Ï„ = 100-200 Myr, age around 1.5-2.0 Gyr, solar or slightly sub-solar metallicity, and moderate extinction, A(V) ∿ 0.5 mag. We also find that galaxies with masses above M* are typically older than lighter galaxies, as expected in a downsizing scenario of galaxy formation. This trend is, however, model dependent, i.e., it is significantly more evident in the results obtained with some stellar population synthesis libraries, and almost absent in others. © 2013. The American Astronomical Society. All rights reserved.We acknowledge support from the Spanish Programa Nacional de Astronomía y Astrofísica under grants AYA2009-07723-E and AYA2009-10368. SHARDS has been funded by the Spanish MICINN/MINECO under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. O.G.-M., C.M.-T., J.M.R.-E., and J.R.-Z. wish to acknowledge support from grant AYA2010-21887-C04-04. A.A.-H. and A.H.-C. acknowledge financial support from the Universidad de Cantabria through the Augusto G. Linares Program.Peer Reviewe
A data-globe and immersive virtual reality environment for upper limb rehabilitation after spinal cord injury
While a number of virtual data-gloves have been used in stroke, there is little evidence about their use in spinal cord injury (SCI). A pilot clinical experience with nine SCI subjects was performed comparing two groups: one carried out a virtual rehabilitation training based on the use of a data glove, CyberTouch combined with traditional rehabilitation, during 30 minutes a day twice a week along two weeks; while the other made only conventional rehabilitation. Furthermore, two functional indexes were developed in order to assess the patient’s performance of the sessions: normalized trajectory lengths and repeatability. While differences between groups were not statistically significant, the data-glove group seemed to obtain better results in the muscle balance and functional parameters, and in the dexterity, coordination and fine grip tests. Related to the indexes that we implemented, normalized trajectory lengths and repeatability, every patient showed an improvement in at least one of the indexes, either along Y-axis trajectory or Z-axis trajectory. This study might be a step in investigating new ways of treatments and objective measures in order to obtain more accurate data about the patient’s evolution, allowing the clinicians to develop rehabilitation treatments, adapted to the abilities and needs of the patients
SHARDS: A global view of the star formation activity at z∼ 0.84 and z∼ 1.23
et al.In this paper, we present a comprehensive analysis of star-forming galaxies (SFGs) at intermediate redshifts (z ∼ 1). We combine the ultra-deep optical spectro-photometric data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) with deep UV-to-FIR observations in the GOODS-N field. Exploiting two of the 25 SHARDS medium-band filters, F687W17 and F823W17, we select [O ii] emission line galaxies at z ∼ 0.84 and z ∼ 1.23 and characterize their physical properties. Their rest-frame equivalent widths (EW([O ii])), line fluxes, luminosities, star formation rates (SFRs), and dust attenuation properties are investigated. The evolution of EW([O ii]) closely follows the SFR density evolution of the universe, with a trend of EW([O ii]) (1 + z) up to redshift z ≃ 1, followed by a possible flattening. The SF properties of the galaxies selected on the basis of their [O ii] emission are compared with complementary samples of SFGs selected by their MIR and FIR emission, and also with a general mass-selected sample of galaxies at the same redshifts. We demonstrate observationally that the UVJ diagram (or, similarly, a cut in the specific SFR) is only partially able to distinguish the quiescent galaxies from the SFGs. The SFR-M relation is investigated for the different samples, yielding a logarithmic slope ∼1, in good agreement with previous results. The dust attenuations derived from different SFR indicators (UV(1600), UV(2800), [O ii], IR) are compared and show clear trends with respect to both the stellar mass and total SFR, with more massive and highly star-forming galaxies being affected by stronger dust attenuation.The work of A.C. is supported by the STARFORM Sinergia Project funded by the Swiss National Science Foundation, and also benefited from a MERAC Funding and Travel Award. P.G.P.-G. acknowledges support from the Spanish Programa Nacional de Astronomía y Astrofísica under grants AYA2012-31277. A.V.G. acknowledges support from the ERC via an Advanced Grant under grant agreement no. 321323-NEOGAL. N.C.
acknowledges support from the Spanish Ministry of Economy and Competitiveness under grant AYA2013-46724-P. A.A.H. and A.H.C. acknowledge financial support from the Spanish Ministry of Economy and Competitiveness through grant AYA2012-31447, which is partly funded by the FEDER program. A.J.C. is a Ramón y Cajal Fellow of the Spanish Ministry of Science and Innovation and acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through grant AYA2012-30789, partly funded by the FEDER program.Peer Reviewe
The starburst-AGN connection in the merger galaxy Mrk 938: an infrared and X-ray view
Mrk938 is a luminous infrared galaxy in the local Universe believed to be the
remnant of a galaxy merger. It shows a Seyfert 2 nucleus and intense star
formation according to optical spectroscopic observations. We have studied this
galaxy using new Herschel far-IR imaging data in addition to archival X-ray,
UV, optical, near-IR and mid-IR data. Mid- and far-IR data are crucial to
characterise the starburst contribution, allowing us to shed new light on its
nature and to study the coexistence of AGN and starburst activity in the local
Universe. The decomposition of the mid-IR Spitzer spectrum shows that the AGN
bolometric contribution to the mid-IR and total infrared luminosity is small
(Lbol(AGN)/LIR~0.02), which agrees with previous estimations. We have
characterised the physical nature of its strong infrared emission and
constrained it to a relatively compact emitting region of <2kpc. It is in this
obscured region where most of the current star formation activity is taking
place as expected for LIRGs. We have used Herschel imaging data for the first
time to constrain the cold dust emission with unprecedented accuracy. We have
fitted the integrated far-IR spectral energy distribution and derived the
properties of the dust, obtaining a dust mass of 3x10^7Msun. The far-IR is
dominated by emission at 35K, consistent with dust heated by the on-going star
formation activity.Comment: 12 pages, 6 figures, 4 tables, accepted for publication in MNRA
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