2,426 research outputs found
Optimal railway infrastructure maintenance and repair policies to manage risk under uncertainty with adaptive control
The aim of this paper is to apply two adaptive control formulations under uncertainty, say open-loop and closed-loop, to the process of developing maintenance and repair policies for railway infrastructures. To establish the optimal maintenance and repair policies for railway lines, we use a previous design of risk model based on two factors: the criticality and the deterioration ratios of the facilities. Thus, our theory benefits from the Reliability Centered Management methodology application, but it also explicitly models uncertainty in characterizing a facility deterioration rate to decide the optimal policy to maintain the railway infrastructures. This may be the major contribution of this work. To verify the models presented, a computation study has been developed and tested for a real scenario: the railway line Villalba-Cercedilla in Madrid (Spain). Our results demonstrate again that applying any adaptive formulation, the cost of the railway lines maintenance shown is decreased. Moreover applying a Closed Loop Formulation the cost associated to the risk takes smaller values (40% less cost for the same risk than the deterministic approach), but with an Open Loop formulation the generated risk in the railway line is also smaller
El cuestionario CEVEAPEU. Un instrumento para la evaluación de las estrategias de aprendizaje de los estudiantes universitarios
El objetivo de este trabajo era elaborar y validar un cuestionario de evaluación de las estrategias de aprendizaje de los estudiantes universitarios más completo que los clásicamente utilizados. Para ello utilizamos un diseño de validación de pruebas. Usamos dos muestras de estudiantes universitarios, la primera de 545 estudiantes y la segunda de 1127. Los resultados de consistencia interna, validez de constructo, validez predictiva y estabilidad temporal, recogidos en el texto del artículo, son buenos. El producto final es un cuestionario con dos escalas, seis subescalas, veinticinco estrategias y 88 ítems, más sólido y completo que los anteriormente disponibles
Formation of S0 galaxies through mergers. Bulge-disc structural coupling resulting from major mergers
Observations reveal a strong structural coupling between bulge and disc in S0
galaxies, which seems difficult to explain if they have formed from supposedly
catastrophic events such as major mergers. We face this question by quantifying
the bulge-disc coupling in dissipative simulations of major and minor mergers
that result in realistic S0s. We have studied the dissipative N-body binary
merger simulations from the GalMer database that give rise to realistic,
relaxed E/S0 and S0 remnants (67 major and 29 minor mergers). We simulate
surface brightness profiles of these S0-like remnants in the K-band, mimicking
typical observational conditions, to perform bulge-disc decompositions
analogous to those carried out in real S0s. The global bulge-disc structure of
these remnants has been compared with real data, and they distribute in the B/T
- r_e - h_d parameter space consistently with real bright S0s, where B/T is the
bulge-to-total luminosity ratio, r_e is the bulge effective radius, and h_d is
the disc scalelength. Major mergers can rebuild a bulge-disc coupling in the
remnants after having destroyed the structures of the progenitors, whereas
minor mergers directly preserve them. Remnants exhibit B/T and r_e/h_d spanning
a wide range of values, and their distribution is consistent with observations.
Many remnants have bulge Sersic indices ranging 1<n<2, flat appearance, and
contain residual star formation in embedded discs, a result which agrees with
the presence of pseudobulges in real S0s. Contrary to the popular view, mergers
(and in particular, major events) can result in S0 remnants with realistically
coupled bulge-disc structures in less than ~3 Gyr. In conclusion, the
bulge-disc coupling and the presence of pseudobulges in real S0s cannot be used
as an argument against the possible major-merger origin of these galaxies.Comment: 23 pages, accepted for publication in Astronomy and Astrophysics
(version after minor language corrections
Comparative Analysis of the Type III Secretion System Effector Repertoires of Pseudomonas savastanoi Pathovars Pathogenic on Woody Hosts
Comunicación de tipo pósterThe species Pseudomonas savastanoi, a member of the Pseudomonas syringae complex,
includes four pathovars causing knots or excrescences in woody hosts: P. savastanoi pv.
savastanoi (Psv), pv. fraxini (Psf), pv. nerii (Psn) and pv. retacarpa (Psr), comprising isolates
from olive, ash, oleander and broom plants, respectively. Pathogenicity of P. savastanoi is
dependent, among other factors, on the type III secretion system (T3SS) and its effector
(T3E) repertoire. Furthermore, a putative role in the interaction with woody hosts has been
suggested for several of these T3E. The recent availability of the genome sequences of
several P. savastanoi strains isolated from different hosts has facilitated bioinformatics
predictions of their T3SS genes and T3E pools, the study of their distribution in other strains
of the P. syringae complex isolated from woody hosts and the functional analysis of several
of these secreted proteins. As previously reported for Psv, Psn and Psf, here we show that
pathogenicity of Psr ICMP16945, is also dependent on the T3SS. Psv strains NCPPB 3335,
ICMP4352 and PseNe107 share a core set of at least 22 T3E, 18 of which are also encoded in
Psn ICMP16943, Psf ICMP7711 and Psr ICMP16945. However, these three strains encode
truncated versions of 1-2 of these 18 T3E and, Psr ICMP16945 contains three pathovarspecific
T3E. Our results also show that several T3E, including HopAO1, are phylogenetically
clustered across the P. syringae complex according to the woody/herbaceous nature of their
host of isolation, suggesting host specialization of these effectors in this complex.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Annual report on Sunspot Counting Program 2014
Este programa observación nació a finales del año 2012 en la Universidad de Extremadura con el fin de ampliar aún más nuestra investigación en la reconstrucción de la actividad solar. Desde el 1 de Enero de 2013, nuestros recuentos de manchas solares se han presentado al Real Observatorio de Bélgica (ROB) como contribución a los esfuerzos internacionales de mantener y actualizar el número internacional de Manchas Solares. Para ello, hemos utilizado un pequeño refractor apocromático de 80 mm de diámetro de objetivo y 550 mm de longitud focal, a fin de proyectar una imagen de 150 mm de diámetro en una plantilla.
Este informe proporciona un conjunto completo de los datos obtenidos durante el año 2014, con cuatro tablas que muestran nuestros datos. Por otra parte, el índice de referencia de las manchas solares se compara con nuestros resultados.
Esperamos que esta publicación sea de utilidad a la comunidad científica que estudia el número de manchas solares: la mayor serie de índices solares derivadas de la observación directa del Sol.This program was born in late 2012 at the University of Extremadura in order to further extend our research in the reconstruction of past solar activity. Since 1st January 2013, our sunspot counts have been submitted to the Royal Observatory of Belgium (ROB) as a contribution to the international effort of maintaining and updating the International Sunspot Number. For this purpose, we have used a small apochromatic refractor –80mm of objective diameter and 550mm of focal length– to project a 150mm diameter image onto a template.
In this report, we provide a complete set of data obtained throughout the year 2014, with four Tables showing our data. Moreover, the reference sunspot index is compared with our results.
We hope that this publication be useful to the scientific community studying the sunspot number: the longest solar index series derived from direct observation of the Sun
La dinámica demográfica y el planeamiento urbano en Vigo desde 1960. Impacto del proceso de industrialización desarrollista
The intense process of industrialization and technocrat planning territorial of the years 1960, have modified the demographic dynamics and the urban structure of the city of Vigo deeply. Theses policies serves as base to study the impacts taken place on the demographic evolution into the city, and the planning figures that should order the populational and physical growth of Vigo. The intense flow inmigratory, a planning ineffective and great floor consumer cause an unbalanced urban development from a demographic point of view, and disordered from the urbanístic perspective.El intenso proceso de industrialización desarrollista y de planificación territorial tecnócrata de los años 1960 ha modificado profundamente la dinámica demográfica y la estructura urbana de la ciudad de Vigo. Estas políticas dirigistas sirven de base para estudiar, por un lado, los impactos producidos sobre la evolución demográfica municipal y en el espacio intraurbano y, por otro, las figuras de planeamiento que deben ordenar y encauzar el crecimiento poblacional y físico de Vigo. El intenso flujo inmigratorio y un planeamiento ineficaz y gran consumidor de suelo provocan un desarrollo urbano desequilibrado desde un punto de vista demográfico y caótico y desordenado desde el urbanístico
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