52 research outputs found

    Transition between Variscan and Alpine cycles in the Pyrenean-Cantabrian Mountains (N Spain): Geodynamic evolution of near-equator European Permian basins

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    In the northern Iberian Peninsula, the Pyrenean-Cantabrian orogenic belt extends E-W for ca. 1000 km between the Atlantic Ocean and Mediterranean Sea. This orogen developed from the collision between Iberia and Eurasia, mainly in Cenozoic times. Lower-middle Permian sediments crop out in small, elongated basins traditionally considered independent from each other due to misinterpretations on incomplete lithostratigraphic data and scarce radiometric ages. Here, we integrate detailed stratigraphic, sedimentary, tectonic, paleosol and magmatic data from well-dated lithostratigraphic units. Our data reveal a similar geodynamic evolution across the Pyrenean-Cantabrian Ranges at the end of the Variscan cycle. Lower-middle Permian basins started their development under an extensional regime related to the end of the Variscan Belt collapse, which stars in late Carboniferous times in the Variscan hinterland. This orogenic collapse transitioned to Pangea breakup at the middle Permian times in the study region. Sedimentation occurred as three main tectono-sedimentary extensional phases. A first phase (Asselian-Sakmarian), which may have even started at the end of the Carboniferous (Gzhelian) in some sections, is mainly represented by alluvial sedimentation associated with calc-alkaline magmatism. A second stage (late Artinskian-early Kungurian), represented by al-luvial, lacustrine and palustrine sediments with intercalations of calc-alkaline volcanic beds, shows a clear up-ward aridification trend probably related to the late Paleozoic icehouse-greenhouse transition. The third and final stage (Wordian-Capitanian) comprised of alluvial deposits with intercalations of alkaline and mafic beds, rarely deposited in the Cantabrian Mountains, and underwent significant pre-and Early Mesozoic erosion in some segments of the Pyrenees. This third stage can be related to a transition towards the Pangea Supercontinent breakup, not generalized until the Early/Middle Triassic at this latitude because the extensional process stopped about 10 Myr (Pyrenees) to 30 Myr (Cantabrian Mountains). When compared to other well-dated basins near the paleoequator, the tectono-sedimentary and climate evolution of lower-middle Permian basins in Western and Central Europe shows common features. Specifically, we identify coeval periods with magmatic activity, extensional tectonics, high subsidence rates and thick sedi-mentary record, as well as prolonged periods without sedimentation. This comparison also identifies some evolutionary differences between Permian basins that could be related to distinct locations in the hinterland or foreland of the Variscan orogen. Our data provide a better understanding of the major crustal re-equilibration and reorganization that took place near the equator in Western-Central Europe during the post-Variscan period

    Simulation of facet heating in high-power red lasers

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    A two-dimensional self-consistent laser model has been used for the simulation of the facet heating of red emitting AlGaInP lasers. It solves in the steady-state the complete semiconductor optoelectronic and thermal equations in the epitaxial and longitudinal directions and takes into account the population of different conduction band valleys. The model considers the possibility of two independent mechanisms contributing to the facet heating: recombination at surface traps and optical absorption at the facet. The simulation parameters have been calibrated by comparison with measurements of the temperature dependence of the threshold current and slope efficiency of broad-area lasers. Facet temperature has been measured by micro-Raman spectrometry in devices with standard and non absorbing mirrors evidencing an effective decrease of the facet heating due to the non absorbing mirrors. A good agreement between experimental values and calculations is obtained for both devices when a certain amount of surface traps and optical absorption is assumed. A simulation analysis of the effect of non absorbing mirrors in the reduction of facet heating in terms of temperature, carrier density, material gain and Shockly-Read-Hall recombination rate profiles is provided

    New lithostratigraphy for the Cantabrian Mountains: A common tectono-stratigraphic evolution for the onset of the Alpine cycle in the W Pyrenean realm, N Spain

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    The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triassic age, have been considered independently from the same phases in neighbouring basins of SW Europe, and even from the eastern part of the same orogeny (the Pyrenean orogeny). In consequence, the beginning of the Alpine cycle in the Cantabrian Mountains has been interpreted within a specific geodynamic context, far from the general evolutionary phases of the western Peri-Tethys basins. Through detailed field work, including geological mapping, sedimentology, lithostratigraphy and petrology of volcanic rocks, and new palaeontological data, here we define several new lithostratigraphical formations and five new tectono-sedimentary cycles (TS I-V) for the initial phases of evolution of the Mesozoic Basque-Cantabrian Basin, interrupted by periods of tectonic stability. To complete this information, we include data from an onshore borehole (Villabona Mine) and two offshore boreholes constrained by 2D reflection seismic profiles acquired in the North Iberian continental platform. The main tectono-sedimentary cycles, related to the deposition of five major identified lithostratigraphic units, can be described as follows: TS I (late Gzelian-early Asselian), relating to the late Variscan deformation and preserved in a single outcrop in all the Cantabrian Mountains (San Tirso Formation). This formation is constituted by medium-distal alluvial fan deposits in which humid intervals predominate, forming some thin coal beds. TS II (Asselian-Sakmarian), a post-Variscan extensional phase with associated calc-alkaline magmatism, represented by profuse volcanic and volcanosedimentary intercalations in the early Permian sedimentary basins (Acebal Formation) and small plutons in surrounding areas. TS III (Kungurian), or reactivation of the post-Variscan extension leading to alluvial and lacustrine carbonate sedimentation in arid climate conditions, which do not change during the rest of the Permian and Triassic periods (Sotres Formation). A generalized karstification in the basin represents the end of Permian deposition, followed by an interruption in sedimentation longer than 30 Myr. The Permian tectono-sedimentary cycles (TS II and TS III) are contemporary with Variscan belt collapse and the basins are controlled by extensional reactivation of NE-SW and E-W Variscan structures, and NW-SE late Variscan structures. TS IV (late Anisian–middle Carnian), renewed sedimentation in more extensive basins, precursors of the great Mesozoic Basque-Cantabrian Basin. This cycle is represented by fluvial deposits (Cicera Formation, or Buntsandstein facies), which are interrupted by the first Mesozoic marine ingression (Rueda Formation, or Muschelkalk facies). TS V (Norian-Rhaetian), or shallow marine carbonate deposits (Transición Formation) related to increasingly compartmentalized sub-basins, controlled by normal faults. This final TS is broadly connected with different basins of the western Peri-Tethys domain. The identification of units TS I-V in the Cantabrian Mountains along with the volcanic character of TS II, all indicate the development of a common post-Variscan to early Alpine tectono-sedimentary evolution for the whole Pyrenean-Cantabrian realm

    Programa de Atención al Ictus en Aragón (PAIA). Estrategia del cambio y resultados en el periodo 2009-2014

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    Introducción En 2008, Aragón tenía tasas de morbimortalidad y discapacidad por ictus superiores a las del conjunto de España. Se estableció la necesidad de desarrollar un Programa de Atención al Ictus (PAIA). Material y métodos Damos a conocer la dinámica de planificación, implantación, evaluación y mejora que se ha desarrollado entre los años 2009-2014 y sus resultados a 5 años. Resultados Se ha mejorado en la estructura, en los procesos y en los resultados, con mejoría en los indicadores clave de la asistencia (audit 2008-2010-2012) y otros: tasa ictus 2013: 2, 07 (2008: 2, 36); 78% ictus atendidos en áreas/unidades en 2014 (30%, 2008); tasa fibrinólisis 8, 3% en 2014 (4, 4%, 2010); fibrinólisis hospitales secundarios (30% total); fibrinólisis con teleictus 9%; descenso de la mortalidad por ictus, 38%; años de vida prematura perdidos 67, 7 (2013)/144 (2008); capacitación de enfermería, desarrollo de la neurosonología, trabajo en red, con protocolos y buenas prácticas compartidos entre sectores sanitarios, etc. Conclusiones La gestión por procesos y equipos multidisciplinares desplegados en una distribución territorial integral, con protocolos y referencias establecidas y una dinámica de evaluación y mejora continua, ha demostrado ser una herramienta potente para garantizar la calidad y la equidad. El PAIA, por su dinámica de mejora sostenida y la implicación de los clínicos, es un buen ejemplo de gestión clínica y trabajo en red. Introduction: In 2008, stroke mortality, morbidity, and disability rates in Aragon were higher than the average in Spain. These data underscored the need to develop a stroke care programme (PAIA). Material and methods: We present the dynamics of planning, implementation, evaluation, and improvement developed between 2009 and 2014 as well as the results of the PAIA after that 5-year period. Results: Structure, processes, and outcomes have improved with reference to the key indicators of healthcare (audit: 2008, 2010, 2012) among others: stroke rate in 2013 was 2.07 (2.36 in 2008); 78% of strokes were managed in stroke units in 2014 (30% in 2008); rate of fibrinolysis was 8.3% in 2014 (4.4% in 2010); fibrinolysis was administered in secondary hospitals (30% of the total); fibrinolysis was administered by Telestroke in 9%; stroke mortality decreased (38%); 67.7 years of potential life lost (YPLL) in 2013 (144 in 2008); nurse training; development of neurosonology; networking; sharing protocols and best practices between health sectors, etc. Conclusions: Integrated process management and multidisciplinary teams distributed and deployed over an entire territory with established protocols, references, evaluations, and continuous development, have been proven powerful tools to ensure both quality and equality. The PAIA is a good example of clinical governance and networking due to its dynamic and sustained improvement and cooperation between clinicians

    The Permian-Triassic rocks of the eastern Iberian Ranges: A general approach in the context of the first stages of the break-up of Pangea.

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    The Permian-Triassic rocks of the eastern Iberian Ranges: A general approach in the context of the first stages of the break-up of Pangea. Field guide of the 10th International Field Workshop of the Pan- European Correlation of the Triassic, 23-27 September 2013.This field guide has been prepared for the 2013 10th International Field Workshop of the Pan-European Correlation of the Triassic. The Field Workshop has been organized as a four-day geological excursion and the guide covers sedimentary aspects of the continental and marine Permian-Middle Triassic rocks of the Iberian Ranges, Spain, but also on related topics such as tectonics, mineralogy, paleoclimate, paleontological content, paleosols, and biotic crises.Peer reviewe

    Role of microecology in chronic inflammatory bowel diseases

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