532 research outputs found
El sistema granito-mineralización de uranio de El Berrocal como análogo natural de un almacenamiento de residuos radiactivos
This work summarizes the analogical study of the radioactive elements and rare earths are deposits applied to the modelling and validation of the migration/retention processes of the high level radioactive artificial isotopes in a geological environment. The geological, mineralogical and geochemical characteristics of the El Berrocal granite- U mineralization system suggest that this system cannot be considered as a global natural analogue for a radioactive waste repository. However, the low-temperature hydrothermal processes, which affected it, including that one which originated the uraniferous mineralization, as well as the weathering processes, can be considered as geochemical processes analogous to those that could take place in a high level radioactive repository.En este trabajo se resume la aplicación del estudio analógico de los yacimientos de elementos radiactivos a la modelización y validación de los procesos de migración/retención de los radioisótopos artificiales de alta actividad, en un medio geológico. Las características geológicas, mineralógicas y geoquímicas del sistema granito-mineralización de uranio de El Berrocal sugieren que dicho sistema no puede considerarse como un análogo natural global de un almacenamiento de residuos radiactivos. Sin embargo, los procesos hidrotermales de baja temperatura que lo afectaron, incluido el que originó la mineralización uranífera, así como los de alteración supergénica, pueden considerarse como procesos geoquímicos análogos a los que podrían tener lugar en un almacenamiento de residuos radiactivos de alta actividad
Current travertines precipitation related to artificial CO2 leakages from a natural reservoir (Gañuelas-Mazarrón Tertiary Basin, SE Spain)
In the framework of a natural CO2 reservoir with CO2 leakages as an analogue of a failed CO2 deep geological storage, the current precipitation of travertines and the associated upwelling of CO2-rich saline groundwater were analysed. This natural analogue is located in the Gañuelas-Mazarrón Tertiary Basin (SE Spain). The study comprises of the chemistry of both groundwater and travertines, including stable isotopes, mineralogy and petrography of the travertines, all this performed after a review of the geology of the basin. In this sense, the basin gathers the main features of a safe natural CO2 reservoir in a deep saline aquifer sealed by a thick marl formation. The aquifer was artificially perturbed by the drilling of wells, inducing the travertines precipitation at these water discharge points. Groundwater is saline, slightly acid, oversaturated in aragonite and calcite and with significant concentrations of heavy elements, some of them toxic. From an isotopic viewpoint, the relative constant δ13C-DIC values suggest that carbon is mainly inorganic in origin with minor organic and mantle contributions. Travertines are basically composed of aragonite or calcite, their precipitation being controlled by a sudden CO2 degassing and minor biological activity. Their δ13C signatures indicate that carbon mainly has an inorganic origin, although some contribution of organic carbon must be considered as well. Furthermore, these carbonate deposits did not precipitate in isotopic equilibrium, as determined by δ18O values. Finally, it is suggested that the appearance of travertines along with their carbon isotopic signatures represent efficient tools for detecting CO2 leakages from any CO2 storage site
IAA : Información y actualidad astronómica (31)
Sumario : Relámpagos en las alturas.--
El misterio de Di Herculis.--
Jets en galaxias activas.--
HISTORIAS DE ASTRONOMÍA. Los All-Star de la física.--
DECONSTRUCCIÓN Y otros ENSAYOS. Cómo “encender” un cuásar .--
EL “MOBY DICK” DE... María Rosa Zapatero Osorio (CAB, CSIC-INTA).--
ACTUALIDAD.--
ENTRE BASTIDORES.--
CIENCIA: PILARES E INCERTIDUMBRES :
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ACTIVIDADES IAA, AGENDA Y RECOMENDADOS.N
El proyecto de El Berrocal: síntesis preliminar
El Berrocal is an international research project on the natural radionuclide migration in a fissured granitic environment. This project is being carried out in the El Berrocal zone, north of the village of Nombela (Toledo). The gelogical formation studied is a granitic pluton with an epithermal vein-type mineralization comprising quartz, sphalerite, pyrite and chalcopyrite; and pitchblende, pyrite, carbonates and barite. The activities of the project are focused on the structural, lithological, geochemical, hydrochemical and hydrogeological aspects of the granite-U mineralization system, in order to establish a migration model of the natural radionuclides of the environment. The concurrence of the tectonic, hydrothermal and supergenic processes has originated several U remobilizations during the deuteric, hydrothermal and supergenic alteration phases, which affected the system. These phases are responsible of the mineralogical species and present distribution of this element within the system. The Th remobilization is much more limited, due to its different geochemical behavior. The present water-rock interaction processes account for the different types of water existing in the system, which are sulphatic, in the shallowest zones, and calcium bicarbonated in the deepest. The U contents in these waters vary from 1 to 100 ppb. The hydrogeology of the zone is controlled, at a local scale, by the topography and the fracture network, and the mineralized quartz dyke plays a major role on the groundwater flow. The isotopic analyses of the U and Th series in the infill materials seem to indicate recent sorption-desorption U processes and coprecipitation with carbonates.«El Berrocal», es un proyecto internacional de investigación sobre la migración de radionucleidos naturales en un medio granítico fisurado. Este proyecto se está desarrollando en la zona de El Berrocal, situada al norte de Nombela (Toledo), en un plutón granítico con una mineralización filoniana epitermal de uranio. El objetivo del proyecto es conocer los aspectos estructurales, litológicos, geoquímicos, hidroquímicos e hidrogeológicos del sistema granito-mineralización de U, a fin de establecer un modelo de migración de los radionucleidos naturales del medio. La convergencia de procesos tectónicos, hidrotermales y supergénicos ha dado lugar a sucesivas removilizaciones del uranio durante las fases deutérica, hidrotermal y supergénica, que afectaron al sistema. Estas fases son las responsables de la mineralogía y distribución actual de dicho elemento en el sistema. La removilización del torio es mucho más restringida debido a su diferente comportamiento geoquímico. Los procesos actuales de interacción agua-roca están condicionando los tipos de aguas existentes en el sistema que son: sulfatadas, en las zonas más superficiales y bicarbonatadas cálcicas, en las más profundas. Los contenidos en uranio en estas aguas están comprendidos entre 1 y 100 ppb. La hidrogeología de la zona está controlada, a nivel local, por la topografía y la red de fracturación, siendo el dique de cuarzo mineralizado un accidente con repercusión importante en la circulación de las aguas subterráneas. El análisis isotópico de las series del uranio y del torio en rellenos fisurales parece indicar procesos recientes de sorción-desorción de uranio y coprecipitación con carbonatos
Efficacy and safety of preoperative preparation with Lugol''s iodine solution in euthyroid patients with Graves’ disease (LIGRADIS Trial): Study protocol for a multicenter randomized trial
Background: Currently, both the American Thyroid Association and the European Thyroid Association recommend preoperative preparation with Lugol''s Solution (LS) for patients undergoing thyroidectomy for Graves’ Disease (GD), but their recommendations are based on low-quality evidence. The LIGRADIS trial aims to provide evidence either to support or refute the systematic use of LS in euthyroid patients undergoing thyroidectomy for GD. Methods: A multicenter randomized controlled trial will be performed. Patients =18 years of age, diagnosed with GD, treated with antithyroid drugs, euthyroid and proposed for total thyroidectomy will be eligible for inclusion. Exclusion criteria will be prior thyroid or parathyroid surgery, hyperparathyroidism that requires associated parathyroidectomy, thyroid cancer that requires adding a lymph node dissection, iodine allergy, consumption of lithium or amiodarone, medically unfit patients (ASA-IV), breastfeeding women, preoperative vocal cord palsy and planned endoscopic, video-assisted or remote access surgery. Between January 2020 and January 2022, 270 patients will be randomized for either receiving or not preoperative preparation with LS. Researchers will be blinded to treatment assignment. The primary outcome will be the rate of postoperative complications: hypoparathyroidism, recurrent laryngeal nerve injury, hematoma, surgical site infection or death. Secondary outcomes will be intraoperative events (Thyroidectomy Difficulty Scale score, blood loss, recurrent laryngeal nerve neuromonitoring signal loss), operative time, postoperative length of stay, hospital readmissions, permanent complications and adverse events associated to LS. Conclusions: There is no conclusive evidence supporting the benefits of preoperative treatment with LS in this setting. This trial aims to provide new insights into future Clinical Practice Guidelines recommendations. Trial registration: ClinicalTrials.gov identifier: NCT03980132. © 202
Podoplanin Associates with CD44 to Promote Directional Cell Migration
Podoplanin, a cancer-associated glycoprotein, interacts with CD44. Both glycoproteins are coordinately upregulated during tumor progression. Podoplanin–CD44 interaction in the cell membrane occurs mainly in migrating cells, and it seems to be required for podoplanin-mediated cell migration and directionality
External validation of multidimensional prognostic indices (ADO, BODEx and DOSE) in a primary care international cohort (PROEPOC/COPD cohort)
Background: Due to the heterogeneous and systemic nature of the chronic obstructive pulmonary disease (COPD), the new guidelines are oriented toward individualized attention. Multidimensional scales could facilitate its proper clinical and prognostic assessment, but not all of them were validated in an international primary care cohort, different from the original ones used for model development. Therefore, our main aim is to assess the prognostic capacity of the ADO, BODEx and DOSE indices in primary care for predicting mortality in COPD patients and to validate the models obtained in subgroups of patients, classified by revised Global Initiative for Chronic Obstructive Lung Disease (2011) and updated Spanish Guideline (2014). Besides, we want to confirm that the prognostic capacity of all indices increases if the number of exacerbations is substituted by the interval between them and to assess the impact on health of the patient''s lifestyle, social network and adherence to treatment. Methods: Design: External validation of scales, open and prospective cohort study in primary care. Setting: 36 health centres in 6 European high, medium and low income countries. Subjects: 477 patients diagnosed with COPD, captured in clinical visit by their General Practitioner/Nurse. Predictors: Detailed patient history, exacerbations, lung function test and questionnaires at baseline. Outcomes: Exacerbations, all-cause mortality and specific mortality, within 5 years of recruitment. Analysis: Multivariate logistic regression and Cox regression will be used. Possible non-linear effect of the indices will be studied by using Structured Additive Regression models with penalised splines. Subsequently, we will assess different aspects of the regression models: discrimination, calibration and diagnostic precision. Clinical variables modulated in primary care and the interval between exacerbations will be considered and incorporated into the analysis. Discussion: The Research Agenda for General Practice/Family Medicine highlights that the evidence on predictive values of prognostic indices in primary care is scarce. A prospective cohort like that of PROEPOC/COPD provides good opportunities for research into COPD and make communication easier between family practitioners, nursing staff, pneumologists and other professionals, supporting a multi-disciplinary approach to the treatment of these patients. Trial registration:ISRCTN52402811. Date: 15/01/2015. Prospectively registered
New species of Eugerres from the Usumacinta Province, México and Guatemala with a redescription of E. mexicanus (Steindachner, 1863) (Teleostei: Gerreidae)
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
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