4,726 research outputs found

    Subsurface deformation and geoid changes due to earthquakes

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    Presented in the First Meeting of Special Study Group 4.176 (Models of temporal variations of the gravity field) of the International Association of GeodesyThe subsurface deformation associated with earthquake faulting is modeled within a three-dimensional homogeneous half-space. It is found that at the boundary of ruptured fault, the strike slip faulting changes mainly the horizontal displacement field, shear stress; while dip slip events affect primarily both the vertical and horizontal components, normal stress. Yiscoelastic gravitational layered model was utilized for computing the postseismic displacement. The modeled postseismic subsurface uplift for five historical events match the geoid high found in the Himalayas. Such geoid residual may serve as a signature of historical events thus can be used to study the existence of seismic gaps.Peer reviewe

    Geodetic signature produced by different sources in a gravitational layered Earth model

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    Presented in the First Meeting of Special Study Group 4.176 (Models of temporal variations of the gravity field) of the International Association of GeodesyWe describe theoretical and computational methods developed by our group for the calculation of displacement, gravity and potential changes resulting from different sources (representing magma bodies and faults) in elastic-gravitational and viscoelastic-gravitationallayered media. The existing codes corresponding to the models are also presented with the information about how they can be obtained for scientific use. The results obtained and work currently in progress are also described in this paper.Peer reviewe

    Multi Objective Ant Colony Optimisation to obtain efficient metro speed profiles

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    [EN] Obtaining efficient speed profiles for metro trains is a multi- objective optimisation problem where energy consumption and travel time must be balanced. Automatic Train Operation (ATO) systems may handle a great number of possible speed profiles; hence optimisation algorithms are required find efficient ones in a timely manner. This paper aims to assess the performance of a particular meta-heuristic optimisation algorithm, a variation of the traditional Ant Colony (ACO) modified to deal with multi-objective problems with continuous variables: MOACOr. This algorithm is used to obtain efficient speed profiles in up to 32 interstation sections in the metro network of Valencia (Spain), and the convergence and diversity of these solution sets is evaluated through metrics such as Inverse Generational Distance (GD) and Normalised Hypervolume (NH). The results are then compared to those obtained with a conventional genetic algorithm (NSGA-II), including a statistical analysis to identify significant differences. It has been found that MOACOr shows a better performance than NSGA-II in terms of convergence, regularity and diversity of the solution. These results indicate that MOACOr is a good alternative to the widely used genetic algorithm and could be a better tool for rail operation managers trying to improve energy efficiency.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Spanish Ministry of Economy and Competitiveness grant number TRA2011-26602.Martínez Fernández, P.; Font Torres, JB.; Villalba Sanchis, I.; Insa Franco, R. (2023). Multi Objective Ant Colony Optimisation to obtain efficient metro speed profiles. Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit. 237(2):232-242. https://doi.org/10.1177/09544097221103351232242237

    Methodological contribution to the measurement of spatial development : the territorial development reports of Andalucía, Spain

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    Los conceptos de cohesión, diversidad y desarrollo territorial han ido ganando progresiva importancia durante los últimos años en el debate sobre las políticas públicas a aplicar sobre el territorio, en especial en el seno de la Unión Europea. Este artículo plantea una clarificación terminológica de los mismos y una aproximación metodológica a su medición, centrándose en la experiencia desarrollada con los Informes de Desarrollo Territorial de Andalucía.The concepts of cohesion, diversity and spatial development have gained increasing importance in the debate on public policies in recent years, in particular within the European Union context. This article raises a terminological clarification of these concepts, as well as a methodological approach to its measurement, focusing on the experience gained with the Spatial Development Reports of Andalusia (Spain).Fil: Pita, M. F,. Universidad de SevillaFil: Pedregal, B.. Universidad de SevillaFil: Torres, J.F.. Universidad de SevillaFil: Fernández-Tabales, A.. Universidad de Sevill

    HAT-P-6b: A Hot Jupiter transiting a bright F star

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    In the ongoing HATNet survey we have detected a giant planet, with radius 1.33 +/- 0.06 RJup and mass 1.06 +/- 0.12 MJup, transiting the bright (V = 10.5) star GSC 03239-00992. The planet is in a circular orbit with period 3.852985 +/- 0.000005 days and mid-transit epoch 2,454,035.67575 +/- 0.00028 (HJD). The parent star is a late F star with mass 1.29 +/- 0.06 Msun, radius 1.46 +/- 0.06 Rsun, Teff ~ 6570 +/- 80 K, [Fe=H] = -0.13 +/- 0.08 and age ~ 2.3+/-^{0.5}_{0.7}Gy. With this radius and mass, HAT-P-6b has somewhat larger radius than theoretically expected. We describe the observations and their analysis to determine physical properties of the HAT-P-6 system, and briefly discuss some implications of this finding.Comment: Accepted for publication in ApJL, 5 pages, minor changes compared to V

    Prevalence of hazardous alcohol use among Spanish primary care providers

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    BackgroundAlcohol use by health care professionals is one of the potential factors that may affect the prevention of hazardous drinking in Primary Care (PC). The objective of the study was to estimate the prevalence of hazardous alcohol use by PC professionals and assess the existing relationship between socio-demographic and occupational variables of PC professionals and their alcohol use.MethodsA descriptive, cross-sectional, observational, multicenter study was performed. Location: PC sites of the Spanish National Health Care System (NHS). Participants: Physicians and nurses, who completed an online questionnaire intended to identify the pattern of hazardous alcohol use through the AUDIT-C test. The study population was recruited through random sampling stratified by regions of the PC sites in the NHS. The primary measurements: Frequency of alcohol use, number of drinks containing alcohol on a typical day, frequency of six or more drinks on one occasion.ResultsOne thousand seven hundred sixty professionals completed the questionnaire. Hazardous alcohol use was detected in 27.80% (95% CI: 25.5-29.7) of PC providers. The prevalence of hazardous alcohol use was higher in males (34.2%) [95% CI: 30.4-37.6] and professionals aged 56years or over (34.2%) [95% CI: 28.2-40.2]. The multiple logistic regression analysis revealed a higher hazardous use in males (OR=1.52; 95% CI: 1.22-1.90), PC physicians (OR=1.42; 95% CI: 1.01-2.02) and professionals with more time worked (OR=1.03; 95% CI: 1.01-1.05).ConclusionOur study shows the current prevalence of hazardous alcohol use among Spanish PC providers, revealing a higher percentage of hazardous alcohol use in healthcare professionals compared to the Spanish general population. Further interventions are required to increase the awareness of negative consequences derived from alcohol use among PC professionals and its impact on the clinical setting
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