49 research outputs found

    Flexural unfolding of complex geometries in fold and thrust belts using paleomagnetic vectors

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    Three-dimensional reconstructions of the subsurface are an important field in Earth Sciences due to their considerable socio-economic implications as exploration of petroleum resources. 3D reconstruction aims at providing a plausible image of the underground which entail the integration of discrete and heterogeneous datasets. They are based on geometric/mechanic laws and are designed to tackle areas with scarce and heterogeneous data. Restoration algorithms are an important tool to validate these 3D geological reconstructions of the subsurface. Restoration is the way back from the deformed to the undeformed states. Undo the deformation and achieve an initial surface with geological meaning is useful to validate the reconstruction of the folded structure and the deformation processes assumed. The main postulate in most restoration methods is the horizontality of the initial layers while restoration algorithms are based in several deformation processes as flexural slip or simple shear. We deepen in restoration techniques in next chapter but we want to emphasize the importance of a continuous feedback between reconstruction and restoration. This become especially important when complex deformation processes are implied and limited data is available. In addition, restoration tools may also be useful to predict deformation patterns for well characterized structures. However, existing restoration methods do not always succeed for complex structures like non-cylindrical, non-coaxial and/or areas undergoing vertical-axis rotations (out-of-plane motions). We suggest using paleomagnetic information, known in the undeformed (horizontal) and deformed states, as an additional and powerful constraint to improve restoration methods and to reduce the uncertainty of the results. The use of paleomagnetism in restoration tools was recommended in the early 1990¿s. So far, however, relatively few researchers have tried using paleomagnetic information to double-check the rotation inferred from restoration methods and hardly ever paleomagnetism is used as primary information of these tools. In this PhD we want to show how paleomagnetism can reduce the uncertainty in restoration tools when it is used as a constraint, particularly for structures with out-of-plane motions. The bedding plane is the basic 2D reference to relate the undeformed and deformed states, but never could be a real 3D indicator. Our proposal is the usage of paleomagnetism together with the bedding plane as references known in both states. The bedding plane determines the horizontal rotation and paleomagnetism the vertical axis rotation. Paleomagnetic vectors are the record of the ancient magnetic field at the time of the rock formation and we assume that it behaves as a passive marker during the deformation process. Its original orientation can be known in the undeformed surface, and it is represented by the paleomagnetic reference vector. If we see the deformation mechanisms, paleomagnetism allow reducing the number of variables, since it is a passive marker that records the internal deformation and provides us with information of vertical axis rotation. Because accurate paleomagnetic data is necessary to improve results we also work on a good data acquisition. Paleomagnetism may be incorporated in many restoration tools, particularly; we centre our study in geometrical surface unfolding algorithms valid for globally developable surfaces. Developable surfaces are those with Gaussian curvature equal to zero everywhere. These surfaces in geology are stratigraphic horizons folded under flexural conditions that have minimum internal deformation. That implies surfaces isometrically folded with preservation of lengths and angles and consequently with preservation of area. By globally we mean that these constraints are valid almost everywhere but there are areas where internal deformation is possible. We can find this kind of structures in the fold and thrust belts of competent layers at crustal levels. In order to test the restoration methods we develop analog models of complex structures. Laboratory-scale models are based on non-coaxial structures of External Sierras (Pyrenees). These analogs are digitalized with photogrametry and X-Ray CT scanner. In this way, models are completely characterized before and after deformation. This allows the calculus of real deformation of the folded surface and the comparison of the restored surface with the initial one

    Aplicación de diseño social a la mejora de las instalaciones del patio de infantil del colegio público CEIP María Moliner

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    El Diseño Social surge como evolución del concepto de diseño tradicional, para alejarse de la producción industrial y centrarse en resolver los problemas de un colectivo a través de la participación de éste en todo el proceso de diseño. Este proyecto recoge una investigación en este concepto y otras metodologías de diseño como Design Thinking, para realizar una aplicación de las mismas en el rediseño del patio de infantil del colegio público CEIP María Moliner de Zaragoza.Esta nueva interpretación del diseño experimenta un momento de auge y varias comunidades comienza a aplicarla para resolver las necesidades de su contexto. Es éste otro de los motivos por los que se plantea el proyecto, para documentar todo el proceso realizado en la aplicación dentro del ámbito educativo y así quede disponible como un ejemplo para otras comunidades interesadas en proyectos de Diseño Social.Además, en el ámbito educativo se dan los distintos factores que favorecen el surgimiento de proyectos de diseño social, ya que cuenta con una comunidad receptiva a la innovación y comprometida, pero que encuentra distintos obstáculos para resolver sus necesidades de forma autónoma al no disponer de los recursos necesarios. Éste es también el caso del CEIP María Moliner, por lo que resulta de gran interés realizar el proyecto de Diseño Social en este entorno, más específicamente en la mejora de las instalaciones de su patio de recreo infantil.<br /

    Analysing non-coaxial folding effects in the Small Circle Intersection method

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    The Small Circle (SC) tools analyse the stereographic tracks (small circles) followed by the palaeomagnetic vectors during folding processes. Working with interfolding and synfolding remagnetizations, the Small Circle Intersection (SCI) method allows finding the best solution of grouping that should correspond with the remagnetization direction. Once this is known, it is possible to determine the magnetization age as well as the degree of bed tilting at this moment. The SC tools are based on some assumptions, among which the coaxiality between the different deformation events is the one addressed in this work (i.e. absence of vertical axis rotations, VARs, or differential horizontal axis rotations, dHARs). This assumption is based on the necessity of knowing the rotation axis for folding after the acquisition of the remagnetization, and SC tools consider the bedding strike as this axis, something that is only accomplished under coaxial folding. In order to explore how non-coaxiality affects the solutions derived from the SC methods, we first (i) identify the variables that control these errors through simple models that only consider two theoretical palaeomagnetic sites, after that it is possible (ii) to derive the mathematical relationships between them. Finally, we (iii) simulate errors derived from the use of SC tools using a population of 30 palaeomagnetic sites recreating different possible scenarios with VARs and dHARs in nature.Research financed by the projects DR3AM- CGL2014-55118 and CGL2016-77560-C2 from the Spanish Ministry of Science (MINECO) and by the Applied Geology (GeoAP-E0117R) and Geotransfer groups of the Government of Aragon, as well as by the project BU235P18 (Junta de Castilla y Leon, Spain) and the European Regional Development Fund (ERD). It has also benefited from the MAGIBER-II network (CGL2017-90632-REDT) funded by the Ministry of Science, Innovation and Universities

    Structural neuroimaging biomarkers for obsessive-compulsive disorder in the ENIGMA-OCD consortium: medication matters

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    No diagnostic biomarkers are available for obsessive-compulsive disorder (OCD). Here, we aimed to identify magnetic resonance imaging (MRI) biomarkers for OCD, using 46 data sets with 2304 OCD patients and 2068 healthy controls from the ENIGMA consortium. We performed machine learning analysis of regional measures of cortical thickness, surface area and subcortical volume and tested classification performance using cross-validation. Classification performance for OCD vs. controls using the complete sample with different classifiers and cross-validation strategies was poor. When models were validated on data from other sites, model performance did not exceed chance-level. In contrast, fair classification performance was achieved when patients were grouped according to their medication status. These results indicate that medication use is associated with substantial differences in brain anatomy that are widely distributed, and indicate that clinical heterogeneity contributes to the poor performance of structural MRI as a disease marker

    An Empirical Comparison of Meta- and Mega-Analysis With Data From the ENIGMA Obsessive-Compulsive Disorder Working Group

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    Objective: Brain imaging communities focusing on different diseases have increasingly started to collaborate and to pool data to perform well-powered meta- and mega-analyses. Some methodologists claim that a one-stage individual-participant data (IPD) mega-analysis can be superior to a two-stage aggregated data meta-analysis, since more detailed computations can be performed in a mega-analysis. Before definitive conclusions regarding the performance of either method can be drawn, it is necessary to critically evaluate the methodology of, and results obtained by, meta- and mega-analyses. Methods: Here, we compare the inverse variance weighted random-effect meta-analysis model with a multiple linear regression mega-analysis model, as well as with a linear mixed-effects random-intercept mega-analysis model, using data from 38 cohorts including 3,665 participants of the ENIGMA-OCD consortium. We assessed the effect sizes and standard errors, and the fit of the models, to evaluate the performance of the different methods. Results: The mega-analytical models showed lower standard errors and narrower confidence intervals than the meta-analysis. Similar standard errors and confidence intervals were found for the linear regression and linear mixed-effects random-intercept models. Moreover, the linear mixed-effects random-intercept models showed better fit indices compared to linear regression mega-analytical models. Conclusions: Our findings indicate that results obtained by meta- and mega-analysis differ, in favor of the latter. In multi-center studies with a moderate amount of variation between cohorts, a linear mixed-effects random-intercept mega-analytical framework appears to be the better approach to investigate structural neuroimaging dat

    Selecció de novetats editorials de comunicació

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    Obra col·lectiva biennal, creada per l'Institut de la Comunicació de la Universitat Autònoma de Barcelona (InCom-UAB), l'any 2000. La setena edició, corresponent al bienni 2011-2012, va comptar amb el suport de la Generalitat de Catalunya; el patrocini de Gas Natural Fenosa; la col·laboració científica del Baròmetre de la Comunicació i la Cultura (Fundacc); la subscripció institucional de l'Ajuntament de Barcelona, el Col·legi de Periodistes de Catalunya i la Societat Catalana de Comunicació (filial de l'Institut d'Estudis Catalans); i la col·laboració acadèmica de l'Observatori de la Comunicació Local (OCL InCom-UAB)/URV/Diputació de Barcelona, l'Observatori de Polítiques de Comunicació (OPC InCom-UAB), i el Portal de la Comunicació (InCom-UAB).En el marc del Grup Internacional d'Estudis sobre Comunicació i Cultura (InCom-UAB), reconegut com a Grup Consolidat de Recerca de la Generalitat de Catalunya per al període 2010-2013 (Referència de concessió 2009 SGR 00615).Aquest capítol aporta una selecció d'obres d'autors vinculats a universitats i institucions catalanes, editades a Catalunya durant els anys 2011 i 2012, elaborada a partir de la base de dades del catàleg de la Biblioteca de Comunicació i Hemeroteca General de la Universitat Autònoma de Barcelona, seguint els criteris acadèmics que el Portal de la Comunicació InCom-UAB (www.portalcomunicacio.cat) utilitza a la seva secció "Novetats editorials". Es tracta d'una relació en la qual es prioritzen les publicacions científiques per davant de les publicacions de caràcter més mediàtic i tècnic

    Experimentando con armas ibéricas de hierro. La producción del metal en hornos de “tiro natural”

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    We present the results of two experimental attempts to obtain iron in natural draft furnaces by bloomery process, extrapolating its possibilities for the Iberian cultures. We describe the physical processes involved in the process and we propose a model of metallurgical and mining exploitation based on the concentration of the means of production in areas closed to raw materials (ore and wood).Se exponen los resultados de dos intentos experimentales para obtener hierro en sendos hornos del tipo de “tiro natural” mediante el proceso de reducción directa, extrapolando sus posibilidades para el mundo ibérico. Se describen los principios físicos que intervienen en el proceso y se propone un modelo de explotación minero- metalúrgica basado en la concentración de los medios de producción en zonas próximas a las materias primas (mineral y madera)

    Secretory immunoglobulin A (s-IgA) reactivity to acute psychosocial stress in children and adolescents: The influence of pubertal development and history of maltreatment.

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    Background: Mucosal secretory immunoglobulin A (s-IgA) is an antibody protein-complex that plays a crucial role in immune first defense against infection. Although different immune biomarkers have been associated with stress-related psychopathology, s-IgA remains poorly studied, especially in youth. Objectives: The present study investigated how s-IgA behaves in front of acute psychosocial stress in children and adolescents, including possible variability associated with developmental stage and history of childhood maltreatment (CM). Methods: 94 children and adolescents from 7 to 17 years (54 with a current psychiatric diagnostic and 40 healthy controls) drawn from a larger Spanish study were explored (EPI-Young Stress Project). To assess biological reactivity, participants provided five saliva samples during an acute laboratory-based psychosocial stressor, the Trier Social Stress Test for Children (TSST-C). Samples were assayed for s-IgA, as well as for cortisol. Pubertal development was ascertained by Tanner stage and CM following TASSCV criteria. Results: We observed s-IgA fluctuations throughout the stressor, indicating the validity of TSST-C to stimulate s-IgA secretion (F(4,199) = 6.200, p <.001). Although s-IgA trajectories followed a reactivity and recovery pattern in adolescents, children exhibited no s-IgA response when faced with stress (F(4,197) = 3.406, p =.010). An interaction was found between s-IgA and CM (F(4,203) = 2.643, p =.035). Interestingly, an interaction between developmental stage, CM history and s-IgA reactivity was identified (F(12,343) = 2.036, p =.017); while children non-exposed to maltreatment exhibited no s-IgA changes to acute stress, children with a history of CM showed a similar response to adolescents, increasing their s-IgA levels after the psychosocial stressor. Conclusion: Acute psychosocial stress stimulates s-IgA secretion, but only after puberty. However, children with a history of maltreatment exhibited a response resembling that of adolescents, suggesting an early maturation of the immune system. Further studies are needed to clarify the validity of s-IgA as an acute stress biomarker, including additional measures during stress exposure. Keywords: Acute stress; Adolescents; Childhood maltreatment; Children; Developmental stage; TSST-C; secretory Immunoglobulin A (s-IgA)

    Riesgo de subsidencia kárstica en áreas urbanas: el caso de Zaragoza

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    Parte del monográfico "Riesgos geológicos externos".[EN] This paper deals with the problems generated by karst in gypsum around Zaragoza, the development of alluvial sinkholes and the concomitant risks. Sinkhole geometry depends on the mechanical behaviour of the cover overlying the evaporitic bedrock: non-cohesive soils favour the development of basin and funnel shaped dolines, whereas cohesive covers lead to the development of well-shaped collapses. Surface survey in areas prone to develop dolines is based on aerial photographs, in situ features (such as topographic depressions, stepped ground, anomalous man-made fills, wet-ground vegetation), and location of building pathologies in urban areas. In some cases, the structure and geometry of dolines can be studied in section (road cuts, for instance), where the features of natural fills allow to characterize the evolutionary patterns and sedimentation- subsidence interactions. Through dating of such fills the rate of subsidence can be estimated, and linked to possible episodes of climate variations. Doline evolution through time, either by comparison of aerial photographs taken in different years or by instrumental survey, yields the scenario of a dynamic process with subsidence rates up to 12 cm/year, where cycles of steady subsidence periods and sudden collapse are identified. In the Zaragoza area, the consequences of karst subsidence are outstanding. They dramatically increased from the 70’s, when large portions of the territory, formerly of agricultural use, turned into urban, industrial and service uses. Prevention and hazard management of karstic risks on urban and peri-urban areas must include: 1) early detection of the problem, in surface as well as underground (by means of geophysical surveys), and 2) adaptation of land use to the degree of affection by karst and the potential susceptibility. Geology, geotechnics and engineering have specific roles on risk management strategies by diminishing either the exposition to karst hazard or the vulnerability of man made structures.[ES] Este trabajo analiza, desde múltiples puntos de vista, la problemática del karst en yesos en el entorno de Zaragoza, el desarrollo de dolinas aluviales y los riesgos que éstas conllevan. La morfología de las dolinas depende del comportamiento mecánico de la cobertera situada sobre el sustrato yesífero: en coberteras sin cohesión aparecen morfologías en embudo y en cubeta, producidas por subsidencia continuada, mientras en coberteras con cohesión se producen dolinas en ventana provocadas por colapso brusco. El reconocimiento superficial de las dolinas se basa en la observación de fotografías aéreas, en el análisis visual del terreno (depresiones topográficas, escalones, áreas de vegetación o rellenos antrópicos anómalos) y en la observación y análisis de daños en áreas urbanizadas. También pueden estudiarse la geometría y la estructura interna de las dolinas en secciones del terreno donde éstas hayan quedado expuestas. Así, las características de sus rellenos naturales permiten conocer las pautas y tasas de evolución y las interacciones entre la subsidencia kárstica y los procesos sedimentarios. El estudio de la evolución temporal de las dolinas, a partir de la comparación de fotografías aéreas de distintos años o del seguimiento instrumental de las mismas, ha permitido reconocer que se trata de un proceso dinámico que llega a alcanzar velocidades de hundimiento de 12 cm/año. En dicha evolución es frecuente la ocurrencia cíclica de periodos de subsidencia lenta y eventos de hundimiento brusco. La afección causada por la subsidencia kárstica en Zaragoza es muy significativa. Ésta se incrementó a partir de los años 70 del siglo pasado, cuando buena parte del suelo agrícola que circundaba la ciudad fue destinado a uso urbano, industrial y grandes infraestructuras. La prevención y manejo del riesgo kárstico en áreas urbanas y peri-urbanas debe contemplar: (1) la detección precoz de los fenómenos tanto en superficie como en profundidad (a partir de estudios geofísicos), y (2) la adaptación del uso del suelo a su grado de afección por fenómenos kársticos y a su susceptibilidad potencial a los mismos. La geología, la geotecnia y la ingeniería desempeñan, cada una, un papel específico en la estrategia para reducir el riesgo, bien sea evitando la exposición al peligro o disminuyendo la vulnerabilidad de las construcciones.Peer reviewe
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