311 research outputs found
How Europeans move: a moderate-to-vigorous physical activity and sitting time paradox in the European Union
Objectives: This study aimed to assess the interactions between physical activity (PA) and sedentary behaviour in a large population taking account of major sociodemographic characteristics. Study design: Cross-sectional population-based study. Methods: Data from 28,031 individuals living in the European Union who were aged ≥15 years were retrieved from a cross-sectional survey, the Eurobarometer 2017. Interactions among the four mobility components (vigorous, moderate, walking activity and sitting time) were assessed at the individual level across age, gender and place of residence, and at the country level by compositional data analysis, hierarchical linear regressions and principal component analysis. Results: The most frequently reported PA was walking; however, sitting time represented >95% of the reported weekly times, whereas moderate-to-vigorous PA (MVPA) represented <1%. Women reported less PA and sitting time, age decreased total PA and increased sitting time, and individuals living in large urban areas reported lower PA and higher sitting times. MVPA decreased with age (β = -0.047, P < 0.001) and was lower in women (β = -0.760, P < 0.001) and those living in large urban areas (β = -0.581, P < 0.001), while walking and sitting times increased with age, being higher in women and lower in those living in rural areas. At the country level, sitting time was positively associated with moderate activity (β = 0.389, P = 0.041) and marginally non-significant with MVPA (β = 0.330, P = 0.087). Conclusions: Walking was the highest contributor to weekly PA, whereas sitting time was paradoxically associated with higher MVPA. Specific measures to reduce sitting time are required to achieve an active lifestyle
Distribución temporal del tamaño de los molariformes de Ursus spelaeus Ros.-Hein.ibérico
[Abstract] This paper deals with a metrical comparison of cheek-teeth length of Ursus spelaeus Ros.-Hein.Iberian population representatives
Overexploitation and water quality in the Crevillente aquifer (Alicante, SE Spain)
The Crevillente aquifer is a karstic aquifer, situated in Alicante province in the SE of Spain. The aquifer basically comprises a series of Jurassic limestones and dolomites, belonging to the Betic Cordillera. Intense exploitation of the aquifer started in the early 1960s. Exploitation was initially concentrated in two sectors of the Sierra de Crevillente and, years later, extended to a third sector. As a consequence of abstractions that were much greater than recharge into the system, a continual drop in the water level persisted for several decades. These abstractions have occasionally caused local dewatering over depths of more than 300 m. From a hydrogeological point of view, the aquifer dewatering in one of the sectors was accompanied by increased mineralization and a fall in quality of the groundwater, and several boreholes had to be abandoned. In recent years, the degree to which the aquifer is overexploited has fallen considerably, and it appears to have entered a new hydrodynamic stage. New hydrogeochemical characterisations have been carried out, which indicate that the aquifer water is relatively strongly mineralised due, fundamentally, to the dissolution of evaporite rocks. On the other hand, deterioration in water quality as a consequence of the degree of overabstraction can also be confirmedDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEGeneralitat ValencianaUNESCOpu
Organic matter accumulation during the Holocene in the Guadalquivir marshlands (SW Spain)
The distribution of biomarker compounds and magnetic susceptibility observed in the sediment from a 20 m core drilled in the
marshlands of the estuarine region of the Guadalquivir River (southwest coast of Spain) has allowed us to reconstruct the
palaeoenvironmental evolution of this area during the Holocene. Several organic compounds (n-alkanes, ra-ketones, n-alkanols,
n-alkanoic acids and organic sulphur), as well as different biomarker ratios, have been used to show changing environmental
conditions through time. These geochemical proxies suggest good preservation of the organic matter, although some diagenesis
has occurred to particular organic compounds, especially the n-alkanoic acids. Our data indicate a major allochthonous supply of
terrestrial plants, with less influence from aquatic plants or algae through the core. There are markedly different palaeoenvironmental
conditions between the uppermost 5 m (last 6ka cal. B.P.) and the rest of the core. From 5 m (ca 6ka cal. B.P.) to 19 m
(ca 8ka cal. B.P.) depth the palaeoenvironmental conditions were almost constant. Based on organic sulphur content and
n-alkane content logs, anoxic conditions prevailed from 8 to 6ka cal. B.P., while oxic conditions with enhanced convection of
water (prevalence of fluvial input), and consequently a greater organic matter supply, predominated in the upper 5 m of the core.
Similarly, little variation in the magnetic susceptibility profile below 5 m indicates stable environmental conditions, while in the
upper 5 m conditions shifted to one with elevated water input and clastic sediment supply. This is linked to palaeofloral
alterations in the Guadiamar/Guadalquivir drainage basins and/or anthropogenic effects. We propose that from ca 8 to 6 ka cal.
B.P. a stable landscape physiognomy in the surroundings of the estuarine area of the Guadalquivir River, with a predominance of
pines and grassland. However, over the last 6ka cal. B.P. a variation in the terrestrial plant biomarker compounds suggests an
alternation of relatively dry and humid phases and/or the impact of human populations on altering the vegetation community
have occurred
Geochemical characterization of the mining district of Linares (Jaen, Spain) by means of XRF and ICP-AES
Linares (Jaen, Spain) has been subjected to an intense mining and metallurgic activity during 2500 years. Basically, lead and silver have been extracted from galena; as well as copper and zinc. Different studies have been conducted to evaluate trace element concentrations to obtain relationships with anthropogenic and geologic factors. The analytical results of these studies have been obtained with ICP-AES. This analytical technique is relatively expensive and inaccessible in zones with scarce economic means. In this study, XRF analyses have been conducted and the obtained results are presented, as well as a comparison with the previously obtained ICP results. In both cases, a cluster analysis has been made to try to identify the same relations in the target area. 5 groups have been identified, mainly related with lithology. Only 10 of the 122 grid squares (each one of 1 km2) are classified in different groups if the cluster analysis is conducted with XRF results or ICP results. ICP classifies better where these grid squares are located, mostly, in contact zones of different lithologies
Wide band-gap tuning Cu2ZnSn1-xGexS4 single crystals: Optical and vibrational properties
The linear optical properties of Cu2ZnSn1-xGe x S4 high quality single crystals with a wide range of Ge contents (x=0.1, 0.3, 0.5, 0.7, 0.9 and 1) have been investigated in the ultraviolet and near infrared range using spectroscopic ellipsometry measurements. From the analysis of the complex dielectric function spectra it has been found that the bandgap E 0 increases continuously from 1.49eV to 2.25eV with the Ge content. Furthermore, the evolution of the interband transitions E 1A and E 1B has been also determined. Raman scattering using three different excitation wavelengths and its analysis have been performed to confirm the absence of secondary phases in the samples, and to distinguish between stannite, wurtzite, wurzstannite and kesterite structures. Additionally, the analysis of the high resolution Raman spectra obtained in samples with different [Ge]/([Ge]+[Sn]) ratios allows describing a bimodal behavior of the dominant A modes. The understanding of the incorporation of Ge into the Cu2ZnSnS4 lattice is fundamental in order to develop efficient bandgap engineering of these compounds towards the fabrication of kesterite based solar cells with enhanced performanceThis work was supported by the Marie Curie-ITN project (KESTCELL, GA: 316488), Marie Curie-IRSES project (PVICOKEST, GA: 269167), AMALIE (TEC2012-38901-C02-01) and SUNBEAM (ENE2013-49136-C4-3-R) project funded by the Spanish Ministry of Economy and Competitiveness. RC acknowledges financial support from Spanish MINECO within the Ramón y Cajal program (RYC-2011-08521
Cu2ZnSnS4 thin film solar cells grown by fast thermal evaporation and thermal treatment
Cu2ZnSnS4 thin films have been produced via rapid thermal evaporation of off-stoichiometric kesterite powder followed by annealing in an Ar atmosphere. Different heating rates were applied during the thermal treatments. The chemical composition and structural properties of the deposited layers as well as the distribution of the elements through the kesterite thin film have been investigated. The initial growth of a SnS secondary phase during evaporation led to the formation of this secondary phase next to the Mo back contact. Solar cell power conversion efficiencies were limited to values about 3 % due to this secondary phase. Furthermore, an increased open circuit voltage was demonstrated by using a Zn(O,S) buffer layerThis work was supported by DAAD project (INTERKEST, Ref: 57050358), Marie Curie-ITN (KESTCELLS, GA: 316488) and MINECO project (SUNBEAM, ENE2013-49136-C4-3-R). RC and ES acknowledge financial support from Spanish MINECO within the Ramón y Cajal program (RYC-2011-08521) and (RYC-2011-09212) respectively. SG also thanks the Government of Spain for the FPI fellowship (BES-2014-068533)
Towards the growth of Cu2ZnSn1 xGexS4 thin films by a single-stage process: Effect of substrate temperature and composition
9 págs.; 7 figs.; 2 tabs.Cu2ZnSn1-xGexS4 (CZTGS) thin films prepared by flash evaporation of a Zn-rich Cu2ZnSn0.5Ge0.5S4 bulk compound in powder form, and a subsequent thermal annealing in S containing Ar atmosphere are studied. The effect of the substrate temperature during evaporation and the initial composition of the precursor powder on the growth mechanism and properties of the final CZTGS thin film are investigated. The microstructure of the films and elemental depth profiles depend strongly on the growth conditions used. Incorporation of Ge into the Cu2ZnSnS4 lattice is demonstrated by the shift of the relevant X-ray diffraction peaks and Raman vibrational modes towards higher diffraction angles and frequencies respectively. A Raman mode at around 348-351 cm-1 is identified as characteristic of CZTGS alloys for x = [Ge]/([Sn]+[Ge]) = 0.14-0.30. The supply of Ge enables the reduction of the Sn loss via a saccrifical Ge loss. This fact allows increasing the substrate temperature up to 350º C during the evaporation, forming a high quality kesterite material and therefore, reducing the deposition process to one single stage & 2015 Elsevier B.V. All rights reserved.RC acknowledges financial support from Spanish MINECO within
the Ramón y Cajal programme (RYC-2011-08521) and VIR for the
Juan de la Cierva fellowship (JCI-2011-10782). GB also acknowledges
the CSIC-JAE Pre-doctoral Program, co-funded by the European
Social Fund. This work was supported by the Marie Curie-IRSES
Project (PVICOKEST, GA: 269167), Marie Curie-ITN project (KESTCELL,
GA: 316488), DAAD project (INTERKEST, Ref: 57050358), and
MINECO projects (SUNBEAM, ENE2013-49136-C4-3-R) (TEC2012-
38901-C02-01). A. Scheu is acknowledged for GDOES measurements.Peer Reviewe
Evolución paleoambiental de la mitad sur de la Península Ibérica. Aplicación a la evaluación del comportamiento de los repositorios de residuos radiactivos
Esta publicación refleja los resultados obtenidos de la realización de los proyectos "EQUIP: Evidency from Quaternary Infills Palaeohydrogeology" (F 14W/ CT96/0031), financiado por la UE, "Evolución Paleoclimática de [a Mitad Sur de [a Península Ibérica" financiado por ENRESA y "Paleoclima" financiado por el Consejo de Seguridad Nuclear y ENRESA. La cuenca de Guadix-Baza, sector oriental, es una de las escasas zonas europeas donde se ha conservado un registro razonablemente completo del Pleistoceno. La cuenca de Guadix Baza, en régimen continental desde el Plioceno, funcionó bajo un régimen centrípeto, con abanicos aluviales en los bordes y una zona compleja lacustre en mosaico en su centro. Se ha podido establecer la existencia de una amplia variedad de facies aluviales y fluviales y sus interrelaciones. La sedimentación en el margen lacustre estaba constituida por arenas bioclásticas y lutitas con fósiles, mientras que en zonas más centrales predominaron lutitas yesíferas, lutitas con yeso intrasedimentario, arenas yesíferas yesos y, ocasionalmente, carbonatos que durante un período concreto depositaron los materiales que configuran el "Nivel Calcáreo de Orce", calizas y dolomías con cantidades variables de yeso y terrígenos cerca de los bordes. El trabajo de campo permitió el establecimiento de una serie estratigráfica tipo compuesta, que refleja los principales acontecimiento paleoambientales que tuvieron lugar durante el Pleistoceno. Con el fin de evitar la yesificación de la calcita y aragonito, propia del ambiente lacustre, la serie tipo de ha establecido en el registro del margen lacustre. Con ayuda del análisis paleomagnético y el análisis de la racemización de aminoácidos en conchas de moluscos y ostrácodos se ha establecido la cronología numérica de la sección estratigráfica tipo que cubre desde el límite Plioceno-Pleistoceno hasta unos 250 ka BP, cuando la erosión de la cabecera del río Fardes alcanza la cuenca abriéndola hacia el valle del Guadalquivir y cesando [a sedimentación lacustre. También se ha datado un depósito de terraza fluvial. Se han obtenido datos paleoambientales "instantáneos" mediante el estudio palinológico, el análisis paleobotánico de material silicificado (madera opalizada) o carbonizado (análisis paleoantracológico), el análisis geoquímico orgánico de algunos niveles especialmente favorables. La geoquímica orgánica de biomarcadores de algunos niveles concretos proporcionó datos sobre su origen (plantas terrestres o acuáticas) y confirmó que un conspicuo nivel carbonoso tuvo su origen en un incendio forestal. El análisis paleobiológico basado en la distribución de especies de ostrácodos, gasterópodos y pelecípodos ha permitido una primera aproximación paleoambiental, pese al evidente sesgo introducido por la presencia de fuentes salinas y materiales yesíferos en el área fuente de los abanicos aluviales del límite oriental de la cuenca. Esta interpretación se ha depurado mediante el estudio geoquímico inorgánico, isótopos estables y elementos traza de las conchas calcíticas de ostrácodos. Ello ha permitido el establecimiento de una alternancia de períodos "fríos y húmedos" y "cálidos y áridos" que permiten reconocer de las clases climáticas "mediterráneo seco" y "mediterráneo húmedo" sensu Horowitz (1989), que tienen sus correlatos en el registro paleoclimático de los grandes lagos del rift del Mar Muerto, el Mar Caspio y lagos pluviales de Norte América. La correlación de los datos isotópicos con las paleosalinidades deducidas del estudio de las inclusiones fluidas en yeso intrasedimentario ha permitido corroborar estas interpretaciones. Esto plantea un nuevo enfoque en el análisis del comportamiento de los repositorios de residuos radiactivos de alta
Evolución paleoclimática del sur de la Península Ibérica a partir del registro de la cuenca de Guadix-Baza: un modelo paleoclimático perimediterráneo
El análisis paleoambiental del registro estratigráfico del sector oriental de la cuenca de Guadix-Baza (Granada) se realizó en el marco del 3er Plan de I+D de la Empresa Nacional de Residuos Radiactivos SA junto con un Proyecto financiado por la UE “Evidency from Quaternary Infills Palaeohydrogeology- EQUIP” y otro proyecto “PALEOCLIMA”, conjuntamente financiado por ENRESA y el Consejo de Seguridad Nuclear (CSN)
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