Search results for "Roca"
showing 10 items of 1893 documents
La proteína C-reactiva y la procalcitonina como marcadores precoces de la fuga anastomótica en cirugía colorrectal
2019
Introducción La fuga anastomótica (FA) sigue siendo la complicación más temida después de la resección colorrectal con una incidencia descrita del 2-16% y una tasa de mortalidad del 12-30%. El diagnóstico precoz es fundamental para disminuir sus consecuencias clínicas. Hasta ahora se han propuesto muchos biomarcadores y algunos de ellos se han implementado en protocolos clínicos. Sin embargo, su precisión y utilidad aún se debaten. El objetivo de este estudio es determinar la fiabilidad de la proteína C reactiva (PCR), procalcitonina y neutrófilos en la detección precoz de la FA después de la cirugía colorrectal. Diseño estudio: Estudio prospectivo, observacional y multicéntrico (34 centros…
Light hydrocarbons as a proxy to identify the origin of the gas manifestations in Greece
2017
The geologic emissions of greenhouse gases (CO2 and CH4) have an important natural contribution in the global carbon budget. Tectonics, through faults in geothermal and oil producing areas, play a significant role in the release of C-gases in many non-volcanic regions of the Earth. Methane, the most abundant organic compound in Earth’s atmosphere, has a potential global warming that is 28 times higher than that of CO2 on a 100-year time horizon. In this study, δ13C-CH4, δ2H-CH4 and light hydrocarbon (alkane: CH4, C2H6, C3H8, C3H6, i-C4H10, n-C4H10; alkene C3H6, iC4H8; and aromatic C6H6) gas concentration data of 119 gas samples (103 unpublished data and 16 literature data) from volcanic-hyd…
Mineralogy of the soils altered by fumarolic activity at Nisyros volcano, Greece
2017
Nisyros is the easternmost island of the South Aegean Active Volcanic arc in Greece. It is an active stratovolcano known for its intense hydrothermal activity. In this study we present the results of the mineralogical analyses of 20 soil samples collected in the caldera area. Samples were analysed through X-ray diffraction and the results allow us to divide them in two groups: Lakki Plain and Stefanos Crater. In their majority the soils of Lakki Plain have a main mineralogical assemblage that consists of quartz, feldspar and gismondine (Ca2Al4Si4O16·9H2O). Gismondine as well as stellerite (CaAl2Si7O18·7H2O), which is appearing in some samples, derive from hydrothermal alteration, whilst wol…
Terpenoid composition and origin of amber from the Cape York Peninsula, Australia
2014
The terpenoid composition of fossil resin from the Cape York Peninsula, Australia has been analysed by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to determine its origin. The pyrolysis products were dominated by cadalene-based C15 bicyclic sesquiterpenoids including some C30–C31 bicadinanes and bicadinenes typical of Class II resin derived from angiosperm plants of Dipterocarpaceae. This observation contrasts with the Araucariaceae (Agathis sp.) source previously suggested for the resin based on Fourier transform infrared (FTIR) analyses. Dipterocarpaceae are not known in Australian vegetation but grow abundantly in Southeast Asia including New Guinea, indicating that the geo…
Modeling of wind gap formation and development of sedimentary basins during fold growth: application to the Zagros Fold Belt, Iran
2016
Mountain building and landscape evolution are controlled by interactions between river dynamics and tectonic forces. Such interactions have been extensively studied, however a quantitative evaluation of tectonic/geomorphic feedbacks, which is imperative for understanding sediments routing within orogens and fold-and-thrust belts, remains to be undertaken. Here, we employ numerical simulations to assess the conditions of uplift and river incision necessary to deflect an antecedent drainage network during the growth of one, or several, folds. We propose that a partitioning of the river network into internal (endorheic) and longitudinal drainage arises as a result of lithological differences w…
Origin of methane and light hydrocarbons in natural fluids emissions: A study from Greece.
2018
Abstract Greece, a country characterised by intense seismic and volcanic activity, has a complex geodynamic and geological setting that favours the occurrence of many gas manifestations. In this study, we address the origin of CH 4 and light hydrocarbons in cold and thermal emissions discharging along the Hellenic territory. Also, we investigate their possible relationship with the main geochemical composition of the gases and the different geological settings of the sampling sites. For this purpose we collected 101 new samples that were analysed for their chemical (O 2 , N 2 , CH 4 , CO 2 , He, Ne, Ar, H 2 , H 2 S and C 2 -C 6 hydrocarbons) and isotopic (R/R A , δ 13 C-CO 2 , δ 13 C-CH 4 a…
Subsurface geometries in central sicily FTB as a premise for hydrocarbon exploration
2008
The study concerns a sector of the Maghrebian Sicilian Fold and Thrust Belt (FTB), located in central Sicily between the southern edge of the Madonie Mts. and the Caltanissetta trough. Interpretation of recently acquired seismic profiles, constrained by joint detailed stratigraphy and field investigation, revealed the structure of the study area as formed by a thick pile of deep water carbonate (Imerese and Sicanian) thrusts lying on carbonate platform imbricates. In the forward migration of the FTB, two main tectonic events were envisaged; shallow and deep seated thrusts occurred during the Miocene-early Pleistocene time interval that deformed the former sedimentary cover of the continenta…
Nuevos caminos, territorio y paisaje en la Comarca de la Costera (Valencia). La mirada de los viajeros
2019
Por sus condiciones físicas, el valle de la Costera ha sido históricamente un lugar de paso obligado en el itinerario que, desde la llanura litoral valenciana, se dirige al sur y al centro peninsular. A finales del siglo XVIII se construye una moderna carretera y a mediados del XIX entra en servicio el ferrocarril entre Madrid y Valencia. En este trabajo analizamos la relación que se establece entre los caminos y el paisaje, y cómo esta se ha reflejado en los escritos que los viajeros que, entre finales del siglo XVIII y a lo largo de todo el siglo XIX, recorrieron por carretera y ferrocarril el valle de la Costera. Sus relatos integran estas modernas obras públicas con la visión secuencial…
Fostering sustained teacher learning: a longitudinal assessment of the influence of vision building and goal interdependence on information sharing
2020
To support school improvement, understanding the mechanisms that enhance teachers’ engagement in professional learning activities within schools over time is paramount. The purpose of this three-wave longitudinal study is to examine the role of workplace conditions (school leaders’ vision building and teams’ shared goals), in supporting teachers’ engagement in information sharing over time. To test the directionality of the relationships between the concepts, we analyzed survey data from 655 vocational education and training teachers in the Netherlands using a cross-lagged panel model. Results suggest that teachers’ engagement in information sharing remains stable over time, and the results…
Mechanistic Origins of the pH Dependency in Au-Catalyzed Glycerol Electro-oxidation: Insight from First-Principles Calculations
2021
Electrocatalytic oxidation of glycerol (EOG) is an attractive approach to convert surplus glycerol to value-added products. Experiments have shown that EOG activity and selectivity depend not only on the electrocatalyst but also on the electrode potential, the pH, and the electrolyte. For broadly employed gold (Au) electrocatalysts, experiments have demonstrated high EOG activity under alkaline conditions with glyceric acid as a primary product, whereas under acidic and neutral conditions Au is almost inactive producing only small amounts of dihydroxyacetone. In the present computational work, we have performed an extensive mechanistic study to understand the pH and potential dependency of …