1,481 research outputs found

    Fluid flow evolution in the Alpine-related basement and sedimentary cover structures in the Southern Pyrenees: an integrated structural, petrographic and geochemical approach

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    [eng] This PhD thesis examines the fracture-fluid interactions across different compressional structures affecting both Paleozoic basement and Mesozoic-Cenozoic cover lithologies in the Southern Pyrenees in order to investigate the relationships between fluid flow and deformation. The studied structures include the Estamariu thrust in the Pyrenean Axial Zone and the Sant Corneli-Bóixols anticline along the front of the Bóixols thrust sheet in the Southern-Central Pyrenees. The proposed methodology integrates field data with U-Pb dating and petrographic and geochemical (δ18O, δ13C, 87Sr/86Sr, clumped isotopes and elemental composition) analyses of vein cements, fault rocks and host rocks present in the study area. The Estamariu thrust resulted from a multistage late Paleozoic to Neogene tectonic evolution. Despite this thrust is known to be Variscan in origin, in the study area it places a Devonian pre-Variscan unit on top of a Stephano-Permian late to post-Variscan sequence, indicating that the structures within this thrust zone have to be post-Variscan. The contractional structures found at the contact between Devonian and Stephano-Permian units have been attributed to the Alpine reactivation of the Estamariu thrust. This Alpine-related deformation is consistent with the transposition of the Variscan regional foliation within the main thrust zone and with the formation of a subsidiary thrust zone in the footwall of the Estamariu thrust. Other structures found in the study area, such as extensional fractures, shear bands and normal faults, postdate the reverse structures and have been attributed to the Neogene extension. In the Sant Corneli-Bóixols anticline, the folded units involve Jurassic-mid Upper Cretaceous pre-compression and latest Cretaceous-Paleocene syn-orogenic sedimentary successions detached on Upper Triassic evaporites. Contrary to the Estamariu thrust, in the Sant Corneli- Bóixols anticline this PhD thesis provides the absolute age of deformation reporting 23 U- Pb dates measured in different sets of fracture-filling calcite cements. These U-Pb dates reveal Late Cretaceous to late Miocene age variations, which are coeval with growth strata deposition and Bóixols thrust sheet emplacement (dates from 71.2 ± 6.4 Ma to 56.9 ± 1.4 Ma), tectonic transport of the Bóixols thrust sheet above the southern Pyrenean basal thrust (dates from 55.5 ± 1.2 Ma to 27.4 ± 0.9 Ma) and post-orogenic exhumation of the Sant Corneli-Bóixols anticline (dates younger than 20.8 ± 1.2 Ma). Throughout this long-lived deformation history, the geochemical data of the successive calcite veins allow to analyze the relationships between fluid flow and deformation in the two studied domains. In the Estamariu thrust, the high 87Sr/86Sr ratios of the different calcite cements indicate the interaction between the vein-forming fluids and radiogenic Paleozoic basement rocks. The geochemical evolution from the earliest to the latest calcite cements also evidence a progressive change in the fluid regime and composition during successive compressional and extensional tectonic events. The progressive increase in precipitation temperatures, from 50 ºC to around 210 ºC, and enrichment in δ18Ofluid, from -6.4 to +12 ‰SMOW, in cements attributed to the Alpine compression to cements from the Neogene extension, is probably linked to a higher extent of fluid-rock interaction with basement rocks. By contrast, during the latest stages of the Neogene extension, the geochemistry of the youngest calcite cements evidence the percolation of cold meteoric fluids that indicates a more significant change in the fluid regime, from upward to downward fluid migration. In the Sant Corneli-Bóixols anticline, the fluid origin and the extent of fluid-rock interaction varied in the several structural positions of the fold and according to the age and nature of their stratigraphy and the involved fracture networks. This evidences a compartmentalization of the fluid system. In the core of the anticline and in the lowest part of the synorogenic sequence from the footwall of the Bóixols thrust, the similar petrographic and geochemical features between successive calcite cements and host rocks indicate a closed fluid system, leading to high extent of fluid-rock interaction. This host-rock buffered fluid was likely derived from the surrounding Lower Cretaceous and Upper Cretaceous marine carbonates, respectively. Contrarily, along large faults, such as the Bóixols thrust, which affect the entire anticline and in the fold limbs, the fluid system was open. Large faults registered the upward migration of fluids in thermal and geochemical disequilibrium with surrounding host rocks, as attested by the light δ18O values of their associated vein cements, down to -14 ‰VPDB, and the high temperature of precipitation, up to 120 ºC. The fold limbs registered the infiltration of meteoric waters, corroborated by the low Sr contents and by the δ18O and δ13C values of the vein cements, from -8 to -6 ‰VPDB and down to -10 ‰VPDB, respectively, which are typical values of meteoric carbonates. In the fault zone of the Bóixols thrust, successive fracture systems and related calcite cements highlight an episodic evolution of the thrust zone. The presence of early extensional fractures and a chaotic breccia is consistent with the formation of dilatant fracturing within a process zone (around the fault tip) during initial fault growth, whereas the formation of the latest fracture system points to hybrid shear-dilational failure during propagation of the Bóixols thrust. Similarly, the different structural and fluid flow histories in the footwall and hanging wall of the Bóixols thrust indicate a compartmentalization of the thrust zone. Clumped isotopes applied to vein cements from the footwall evidence a progressive increase in precipitation temperatures from 50 ºC to 117 ºC, approximately, and an enrichment in δ18Ofluid, from -1.8 to +5.5 ‰SMOW. This has been interpreted as a change in the fluid source from meteoric fluids to evolved meteoric fluids due to water-rock interaction at increasing depths and temperatures. Contrary to the footwall, clumped isotopes applied to vein cement from the hanging wall, which is the same cement found in the fault core, revealed temperatures around 95 ºC and δ18Ofluid up to +1.9 ‰SMOW. This has been interpreted as the migration of formation waters from the fault core and towards the hanging wall. Therefore, the Bóixols thrust likely acted as a transverse barrier, dividing the thrust zone into two separate fluid compartments, and a longitudinal drain for migration of fluids. Altogether, the maximum temperatures and δ18Ofluid, up to 120 ºC and +5.5 ‰VSMOW, obtained in the Sant Corneli-Bóixols anticline, implying 3-4 km depth and presence of formation waters, respectively, together with the 87Sr/86Sr ratios of the vein cements, within the range of values documented in the sedimentary cover, discard the transfer of fluids between the basement and the sedimentary cover in the Southern-Central Pyrenees. This indicates that the paleohydrological system in the Sant Corneli-Bóixols anticline was restricted to the Bóixols thrust sheet above the Upper Triassic detachment level. This evaporitic detachment likely acted as a lower fluid barrier, preventing the input of fluids from deeper parts of the belt, as interpreted in other areas of the Pyrenees and in other detached thrust systems as the Central Appalachians and Sierra Madre Oriental. Finally, comparing the results obtained in both studied domains with those reported in previous contributions, this study assesses the fluid flow and deformation relationships at regional scale. On the one hand, this thesis highlights a common fluid flow behavior along strike in the central-eastern part of the southern Pyrenees, where major faults acted as transfer zones for migration of fluid in thermal and geochemical disequilibrium with adjacent host rocks, whereas background fracturing recorded the presence of fluids that highly interacted with surrounding host rocks. Additionally, our data indicates that regardless of the fluid origin and the tectonic context, the fluids that have interacted with basement rocks have a higher 87Sr/86Sr ratio (> 0.710) than those that have circulated through the sedimentary cover (< 0.710). Lastly, extensional deformation structures in the eastern Pyrenees have acted as conduits for hydrothermal fluid migration in Neogene times similarly as in the northern part of the Catalan Coastal Ranges. These fluids likely interacted with basement rocks before ascending through fault zones and related fractures.[cat] Aquesta tesi estudia les interaccions entre fracturació i fluids a diferents estructures (plecs i zones de falles) que afecten els materials del sòcol Paleozoic y de la cobertora Mesozoica- Cenozoica a la Zona Sud-Pirinenca. L’objectiu de la tesi és reconèixer les relacions entre migració de fluids i deformació utilitzant com a anàlegs l’encavalcament d’Estamariu a la Zona Axial i l’anticlinal de Sant Corneli-Bóixols a la part frontal del mantell de Bóixols, Unitat Sud-Pirinenca Central. A cada estructura s’integren dades de camp amb datacions U- Pb i diversos anàlisis petrogràfics i geoquímics (δ18O, δ13C, 87Sr/86Sr, cumpled isòtops i composició elemental) de ciments de calcita, roques de falla i roques encaixants. L'encavalcament d'Estamariu és el resultat d'una evolució tectònica que comprèn des del Paleozoic superior al Neogen, mentre que a l’anticlinal de Sant Corneli-Bóixols, les edats U- Pb revelen deformació des del Cretaci superior fins al Miocè superior. Durant aquesta història de deformació, les dades geoquímiques de les successives venes de calcita permeten analitzar les relacions entre la migració de fluids i la deformació a les dues zones d’estudi. A l’encavalcament d’Estamariu, l'evolució geoquímica dels ciments de calcita evidencia un canvi progressiu en el règim i la composició dels fluids durant successius episodis tectònics de compressió i extensió, de migració ascendent a percolació de fluids. A l’anticlinal de Sant Corneli-Bóixols, l’origen dels fluids i el grau d’interacció fluid-roca van variar en les diverses posicions estructurals del plec i segons l’edat i la naturalesa de la seva estratigrafia i les fractures relacionades. La qual cosa evidencia una compartimentació del sistema de fluids. Al nucli de l’anticlinal i a la part més baixa de la seqüència sinorogènica del bloc inferior del l’encavalcament de Bóixols, les característiques petrològiques i geoquímiques similars entre successius ciments de calcita i les seves roques encaixants indiquen un sistema tancat de fluids i un grau alt d’interacció fluid-roca. Contràriament, al llarg de grans falles, com l’encavalcament de Bóixols, que afecten tot l’anticlinal i als flancs del plec, el sistema de fluids estava obert, registrant la migració ascendent de fluids en desequilibri tèrmic i geoquímic amb les roques encaixants i la infiltració d’aigües meteòriques, respectivament. Tot plegat, aquests resultats indiquen que al anticlinal de Sant Corneli-Bóixols el sistema paleohidrològic estava restringit al mantell de Bóixols per sobre del nivell de desenganxament del Triàsic superior. Aquest nivell evaporític probablement va actuar com un segell evitant l’entrada de fluids de parts més profundes de la serralada, tal com s’interpreta en altres zones del Pirineu i en altres sistemes d’encavalcaments com els Apalatxes centrals i la Sierra Madre Oriental. Finalment, comparant els resultats obtinguts en els dos dominis estudiats amb els resultats reportats en altres contribucions prèvies, aquesta tesi analitza la relació entre migració de fluids i deformació a escala regional. D’una banda, aquesta tesi posa de manifest un comportament comú del flux de fluids al llarg de la part central-oriental de la Zona Sud- Pirinenca, on les falles principals van actuar com a zones de transferència per a la migració de fluids en desequilibri tèrmic i geoquímic amb roques encaixants, mentre que les fractures de escala menor van registrar la presència de fluids equilibrats amb els seus encaixants. A més, les nostres dades també indiquen que, independentment de l’origen del fluid i del context tectònic, els fluids que han interaccionat amb les roques del sòcol tenen una relació de 87Sr/86Sr (> 0,710) superior als fluids que han circulat per la cobertora sedimentària (<0,710). D’altra banda, les estructures de deformació extensiva, tant al Pirineu oriental com a la part nord-est de la Cadena Costera Catalana, han actuat com a conductes per a la migració de fluids hidrotermals al Neogen i en l’actualitat. Aquests fluids probablement van interactuar amb les roques del sòcol abans d’ascendir a través de zones de falla i les fractures relacionades

    Proceso de recuperación funcional tras lesión del ligamento cruzado anterior. Revisión bibiográfica

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    La ruptura del ligamento cruzado anterior (LCA) es una afección muy común y siempre se deberá realizar un tratamiento fisioterápico si se desea obtener la mejor recuperación posible, puesto que es una de las afecciones que cuenta con un mayor tiempo de rehabilitación. El objetivo de esta revisión es recopilar la información disponible al respecto para conocer las bases que deben tener los programas de recuperación funcional del mismo. Se han consultado las plataformas: ¿Pubmed¿ y ¿PEDro¿. Los resultados muestran la efectividad de la realización de un protocolo de rehabilitación acelerado y de la ejecución progresiva de ejercicios en modalidad excéntrica. Además, el entrenamiento funcional es efectivo en la recuperación de la rodilla tras la reparación del LCA y debe ser tenido en cuenta por los médicos, entrenadores y fisioterapeutas. En conclusión, el tratamiento fisioterápico será relevante para la recuperación del LCA y siempre se deberá de informar a los pacientes de la existencia de dos modalidades de tratamiento, conservador y quirúrgico, siendo éste último el más recomendable en el caso de querer recuperar una actividad deportiva previa a la lesión. Finalmente, será muy importante conocer las inquietudes, dudas y expectativas de los pacientes para saber conducir el proceso de recuperación. Rupture of the anterior cruciate ligament (ACL) is a very common complaint and always should be a physiotherapy treatment if you want to get the best possible recovery,since it is one of the conditions which has a longer period of rehabilitation. The objective of this review is to collect available information in order to establish the bases that the functional recovery programs should have. The platforms we have used are: 'Pubmed' and 'PEDro'. The results show the effectiveness of the development of an accelerated rehabilitation protocol and the implementation of progressive eccentric exercise. In addition, the functional training is effective in the recovery of the knee after ACL repair and must be taken into account by the doctors, trainers and physiotherapists. In conclusion, the physiotherapy treatment is relevant for ACL recovery and always you must inform the patients of the existence of two forms of treatment, conservative and surgical treatment, being this last the most recommended if you want to recover a sporting activity prior to the injury. Finally, the fact of knowing what are the concerns, questions and expectations of the patients is very important to know how to drive the rehabilitation process

    Box 4. The pass-through of higher natural gas prices to inflation in the euro area and in Spain

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    Artículo de revistaThis early-release box was published on 30 Septembe

    Real-Time Crowd Counting based on wearable Ephemeral IDs

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    Crowd Counting is a very interesting problem aiming at counting people typically based on density averages and/or aerial images. This is very useful to prevent crowd crushes, especially on urban environments with high crowd density, or to count people in public demonstrations. In addition, in the last years, it has become of paramount importance for pandemic management. For those reasons, giving users automatic mechanisms to anticipate high risk situations is essential. In this work, we analyze ID-based Crowd Counting, and propose a real-time Crowd Counting system based on the Ephemeral ID broadcast by contact tracing applications on wearable devices. We also performed some simulations that show the accuracy of our system in different situations

    Interpretación litoestratigráfica y paleogeográfica del Jurásico marino del este Cantabria-oeste de Vizcaya en base a diagrafías de sondeo y su correlación con series tipo

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    Este trabajo se centra en el estudio del Jurásico marino (Lías y Dogger) de un área de la parte central de La Cuenca Vasco-Cantábrica situada en el este de Cantabria y oeste de Vizcaya donde sus afloramientos son muy escasos pero se dispone de datos de sondeos de exploración petrolífera (Fig 1A y B), poniendo especial interés en la localización y distribución lateral de los niveles de rocas madre de hidrocarburos (black shales) y de potenciales almacenes (unidades carbonatadas fracturadas o dolomitizadas). La sucesión del Jurásico de la Cuenca Vasco-Cantábrica (CVC) está formada por dos unidades diferenciadas por edad y ambiente sedimentario. Por una parte tenemos los materiales del “Jurásico marino” (Robles et al., 1989) que representan la mayor parte de la sucesión (Lías y Dogger) y por otro lado, tenemos los materiales del “Jurásico continental” pertenecientes exclusivamente al Tithoniense Superior y que se engloban en las facies Purbeck que abarcan hasta el Berriasiense (Rat 1962)

    The implementation of blended learning to maximize the listening comprehension skill of the eighth grade, section B students at the Centro Escolar Napoleón Ríos in Santa Ana in the year 2019

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    Students’ listening comprehension skill plays an important role in the English learning process, and in this research project, the investigators considered to implement the blended learning method along with technology sources to maximize student’s listening comprehension skill. To reach this objective, the blended learning method was applied by the researchers to analyze the development of listening comprehension since its combines online educational materials and opportunities for interaction online with traditional classroom method

    Exploring how us popular culture changes first year students' identities and how it fosters their motivations to enroll in the english teacher training program at UNAB, Casona

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    Tesis (Profesor de Inglés para la Enseñanza Básica y Media)Este estudio social fue conducido para poder comprender los roles que juega la cultura popular estadounidense en las motivaciones que los estudiantes tienen al matricularse en la Carrera de pedagogía en inglés en la UNAB, campus Casona y el impacto que esta tiene en las identidades de los alumnos. El área de este estudio no ha sido explorada previamente en el contexto chileno; sin embargo, los resultados proporcionados por la investigación pueden facilitar la comprensión por parte del campo pedagógico con respecto al fenómeno causado por la cultura popular estadounidense. Las preguntas de jerarquización fueron aplicadas para así poder reducir el número de estudiantes que se someterían a la siguiente etapa -entrevista semi estructurada. Para esta etapa, dos de treinta y cuatro estudiantes de primer año de la carrera Pedagogía en Inglés en UNAB, Casona fueron seleccionados. A pesar de que aquellos estudiantes pudieron haber tenido más de una razón para estudiar dicha carrera, fue posible apreciar como la cultura popular estadounidense cambió las identidades y motivaciones que los alumnos tenían al momento de decidir estudiar Pedagogía en Inglés en la Universidad Andrés Bello, campus Casona.This social study was conducted in order to comprehend what roles US Popular Culture plays in the motivations that students have to enroll in the English Teacher Training Program (ETTP) at UNAB, Casona, and its impact on students’ identities. This research area has not been explored before in the Chilean context; however, the results provided by this study might help the English pedagogical field understand the phenomenon caused by US Popular Culture. Ranking questions were applied in order to reduce the number of students who would undergo the next stage - semi-structured interview. The main participants of this qualitative study were two students out of thirty four from first year of the ETTP at UNAB, Casona. Even though, first year students might have had several reasons to study in the ETTP, it was possible to see how US Popular Culture changed the participants’ identities and motivations before and when making a decision to study English pedagogy at UNAB, Casona

    Farmacología de los receptores imidazolínicos

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    Los receptores imidazolínicos son un tipo de receptores especiales. Pueden ser de tres tipos: I1, I2 e I3. Los receptores tipo I1 se encuentran en las membranas celulares de distintas vísceras, pero fundamentalmente se ubican en la médula rostroventrolateral en el núcleo reticular lateral. Estos receptores están unidos a proteínas G y mediante una cascada de señalización producen un efecto hipotensor por su estímulo conjunto con los receptores α2 adrenérgicos por parte de fármacos imidazolínicos como la clonidina, o bien mediante ligandos internos o endazolinas. Los receptores tipo I2 se localizan en las mitocondrias de las neuronas de distintas regiones del sistema nervioso central. Estos receptores no están acoplados a proteínas G pero actúan como moduladores alostéricos de la MAO-A y B, modificando de este modo los niveles de monoaminas siendo estos una potencial diana farmacológica en el tratamiento de enfermedades mentales neurodegenerativas así como del dolor sin producir ningún tipo de dependencia ni tolerancia. Por último, los receptores tipo I3 se encuentran en las células de los islotes β-pancreáticos modulando la secreción de insulina. Esta acción insulinotrópica se debe a dos mecanismos en función de su dependencia a la glucosa: Mediante cierre de canales de potasio sensibles a ATP (glucosa-independientes) y mediante la modulación de la exocitosis de esta (glucosa-dependientes)
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