1,612 research outputs found

    Tensorial analisis of the superposed deformation in the easthern border of the Madrid basin

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    An analysis of Neogene brittle deformation using fault populatĂ­on analysis methods has been carried out between the SW border of the Iberian Range and Altomira Range. Two main paleostress fields have been established: 1) N70E - N120E compression (Altomira paleostress field) ofLate Oligocene - Early Miocene age that induced the formation of the SW border of Iberian Range and Altomira - Pareja thrust belts with reverse and strike-slip faults. 2) N140-N160E compression (Guadarrama paleostress field) of Middle Aragonian - early Pleistocene age that reactivated previous faults with strikeslip movement along the Iberian Range. A superposition of two regional stress fields (Iberian and Guadarrama) is proposed to explain E-W compression that formed Altomira Range. Stress tensorial additions have been realized to check this hypothesis

    Diagnosis and numerical simulations of a heavy rain event in the Western Mediterranean Basin

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    International audienceThe heavy rain event of November 2001 in the western Mediterranean area was synoptically characterized by the presence of a long-lived Omega blocking geopotential pattern. A set of mesoscale numerical simulations using MM5 is performed to investigate the mechanisms responsible for the convection development through several output diagnosis. A potential vorticity evolution showed how dry air masses were extruded from the stratospheric levels promoting strong cyclonic circulation at all levels. Moreover, a deep vertical column of high relative humidity over the Algerian coastline maintained the few and geographically confined convective cells responsible for the heavy precipitation. Mesoscale environment parameters indicated enhanced conditional instability through a deep troposphere layer. Also, strong vertical wind shear values, higher than 50 ms?1 over the troposphere, were derived, indicating enough strength to promote necessary conditions to organize and keep mesoscale convective structures

    The impact of the Kasatochi eruption on the Moon's illumination during the August 2008 lunar eclipse

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    The Moon's changeable aspect during a lunar eclipse is largely attributable to variations in the refracted unscattered sunlight absorbed by the terrestrial atmosphere that occur as the satellite crosses the Earth's shadow. The contribution to the Moon's aspect from sunlight scattered at the Earth's terminator is generally deemed minor. However, our analysis of a published spectrum of the 16 August 2008 lunar eclipse shows that diffuse sunlight is a major component of the measured spectrum at wavelengths shorter than 600 nm. The conclusion is supported by two distinct features, namely the spectrum's tail at short wavelengths and the unequal absorption by an oxygen collisional complex at two nearby bands. Our findings are consistent with the presence of the volcanic cloud reported at high northern latitudes following the 7-8 August 2008 eruption in Alaska of the Kasatochi volcano. The cloud both attenuates the unscattered sunlight and enhances moderately the scattered component, thus modifying the contrast between the two contributions.Comment: Accepted for publication in Geophysical Research Letter

    Fingerprinting Chamaesiphon populations as an approach toassess the quality of running waters

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    "This is the peer reviewed version of the following article: Loza, V.; Morales, A.; Perona, E. and Muñoz-MartĂ­n, M. A."Fingerprinting Chamaesiphon populations as an approach toassess the quality of running waters" River Research and Applications 34 (2018): 595-605 which has been published in final form at https://doi.org/10.1002/rra.3277. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions."Cyanobacterial communities are highly diverse in freshwaters and respond rapidly tochanging environments. Previous studies have highlighted variations in the structureand composition of epilithic cyanobacterial communities in response to eutrophica-tion in watercourses. In the present study, changes in benthic cyanobacterial commu-nities from Guadalix River (Spain) biofilms were examined using temperature‐gradientgel electrophoresis (TGGE) in conjunction with microscopic examination of field‐fixedsamples, focusing on populations of one of the dominant cyanobacteria:Chamaesiphon. Environmental characteristics were determined in order to character-ize the trophic status of the sampling sites. The presence of cyanobacteria in the riverwas determined from complex TGGE patterns, band extraction, and subsequentsequencing of 16S rDNA gene fragments. The microscopic observations revealed thatthe unicellular genus Chamaesiphon and the filamentous genus Phormidium were dom-inant in the studied locations. Within the 2 genera, 4 Chamaesiphon populations wereidentified (Chamaesiphon fuscus, Chamaesiphon starmachii, Chamaesiphon subglobosus ,and Chamaesiphon polymorphus) and Phormidium was represented at the samplingsites by the Phormidium autumnale morphotype. TGGE banding patterns differedamong samplings sites as a function of water quality. The genetic analysis revealed4 phylotypes within the genus Chamaesiphon and 1 phylotype within the classicP. autumnale clade. Chamaesiphon phylotypes were not equally distributed in all thesampling locations. Some phylotypes were related to low nutrient concentrations,while others were associated with eutrophic conditions. Our results support the useof fingerprints of Chamaesiphon populations obtained by TGGE to examine changesin water quality.This work was supported by Grant CGL2013‐44870‐R from the Ministerio de EconomĂ­a y Competitividad, Spai

    Construction of a self-luminescent cyanobacterial bioreporter that detects a broad range of bioavailable heavy metals in aquatic environments

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    Frontiers in Microbiology 6 (2015): 186 This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permissionA self-luminescent bioreporter strain of the unicellular cyanobacterium Synechococcus sp. PCC 7942 was constructed by fusing the promoter region of the smt locus (encoding the transcriptional repressor SmtB and the metallothionein SmtA) to luxCDABE from Photorhabdus luminescens; the sensor smtB gene controlling the expression of smtA was cloned in the same vector. The bioreporter performance was tested with a range of heavy metals and was shown to respond linearly to divalent Zn, Cd, Cu, Co, Hg, and monovalent Ag. Chemical modeling was used to link bioreporter response with metal speciation and bioavailability. Limits of Detection (LODs), Maximum Permissive Concentrations (MPCs) and dynamic ranges for each metal were calculated in terms of free ion concentrations. The ranges of detection varied from 11 to 72 pM for Hg2+ (the ion to which the bioreporter was most sensitive) to 1.54-5.35 ÎŒM for Cd2+ with an order of decreasing sensitivity as follows: Hg2+ >> Cu2+ >> Ag+ > Co2+ = Zn2+ > Cd2+. However, the maximum induction factor reached 75-fold in the case of Zn2+ and 56-fold in the case of Cd2+, implying that Zn2+ is the preferred metal in vivo for the SmtB sensor, followed by Cd2+, Ag+ and Cu2+ (around 45-50-fold induction), Hg2+ (30-fold) and finally Co2+ (20-fold). The bioreporter performance was tested in real environmental samples with different water matrix complexity artificially contaminated with increasing concentrations of Zn, Cd, Ag, and Cu, confirming its validity as a sensor of free heavy metal cations bioavailability in aquatic environmentsThis study was funded by MINECO grants CGL2010-15675 and CTM2013-45775-C2-2-
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