380 research outputs found

    Paleogeographic inversion resulting from large out of sequence breaching thrusts: The León Fault (Cantabrian Zone, NW Iberia). A new picture of the external Variscan Thrust Belt in the Ibero-Armorican Arc

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    Out of sequence breaching thrusts may give rise to duplication of a former thrust stack in map view in the same manner that stratigraphic units are repeated by initial thrusts. In this way, large breaching thrusts may put an inicial paleogeographic pattern out of order, producing apparent paleogeographic inversions at regional scale. The León Fault, an orogen-scale fault located in the Variscan foreland fold-thrust belt of the Iberian Peninsula, known as the Cantabrian Zone, has caused much controversy in the understanding of Iberian Paleozoic tectonics. The León Fault displays all the features of a breaching thrust and from this interpretation a simple paleogeographic pattern results, once both breaching and former thrusts are restored, in contrasts with previously reported paleogeographic models. This approach implies a redefinition of the geological provinces of the Cantabrian Zone, since some major nappes of that zone, so far considered as different tectonic units, are reinterpreted as one single unit repeated by the León Thrust. It also has implications in discriminating between the various kinematic models proposed for the larger Ibero-Armorican Arc, favouring a late bending of an initial linear belt instead of a progressive change in transport direction during nappe emplacement. Finally, the paleogeographic inversion caused by the León breaching Thrust is compared to other orogen-scale paleogeographic inversions associated with antiformal stacks, such as the preAlps with respect to the Helvetic Nappes, and the Ligurian-Tuscan domains in the Apennines

    Paleogeographic inversion resulting from large out of sequence breaching thrusts: The León Fault (Cantabrian Zone, NW Iberia). A new picture of the external Variscan Thrust Belt in the Ibero-Armorican Arc

    Get PDF
    Out of sequence breaching thrusts may give rise to duplication of a former thrust stack in map view in the same manner that stratigraphic units are repeated by initial thrusts. In this way, large breaching thrusts may put an inicial paleogeographic pattern out of order, producing apparent paleogeographic inversions at regional scale. The León Fault, an orogen-scale fault located in the Variscan foreland fold-thrust belt of the Iberian Peninsula, known as the Cantabrian Zone, has caused much controversy in the understanding of Iberian Paleozoic tectonics. The León Fault displays all the features of a breaching thrust and from this interpretation a simple paleogeographic pattern results, once both breaching and former thrusts are restored, in contrasts with previously reported paleogeographic models. This approach implies a redefinition of the geological provinces of the Cantabrian Zone, since some major nappes of that zone, so far considered as different tectonic units, are reinterpreted as one single unit repeated by the León Thrust. It also has implications in discriminating between the various kinematic models proposed for the larger Ibero-Armorican Arc, favouring a late bending of an initial linear belt instead of a progressive change in transport direction during nappe emplacement. Finally, the paleogeographic inversion caused by the León breaching Thrust is compared to other orogen-scale paleogeographic inversions associated with antiformal stacks, such as the preAlps with respect to the Helvetic Nappes, and the Ligurian-Tuscan domains in the Apennines

    The role of the MRS in hydrogeological research

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    Torsion cycles as non-local magnetic sources in non-orientable spaces

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    Non-orientable spaces can appear to carry net magnetic charge, even in the absence of magnetic sources. It is shown that this effect can be understood as a physical manifestation of the existence of torsion cycles of codimension one in the homology of space.Comment: 17 pages, 4 figure

    A mesoscale index to describe the regional ocean circulation around the Balearic Islands

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    Historical oceanographic surveys carried out around the Balearic Islands (western Mediterranean) suggest two different scenarios for the regional ocean circulation. In one scenario, occurring during cold winters, cool water is formed at intermediate layers (100–300 m) in the Gulf of Lions. This Western Mediterranean Intermediate Water (WIW) usually moves southward reaching the Balearic Channels, deflecting the warmer Levantine Intermediate Water (LIW) coming from the Eastern Mediterranean, and even blocking the Ibiza Channel. On the other hand, during mild winters, less WIW is formed and then LIW flows through the channels, appearing at their characteristic depths. The oceanographic surveys around the Balearic Islands (1985–2004) have provided a qualitative index, indicating the presence or not of WIW in the Ibiza Channel, based on the analyses of θS diagrams. A quantitative index based on mean water temperature between 100 and 300 m depth in the channels may also be defined. Both indexes, the qualitative and the quantitative, give consistent information on WIW presence for the period 1985–2004, however, both are short in time and have gaps in the series. In order to obtain a longer and continuous index for WIW presence and then for regional circulation, air–sea heat fluxes at the Gulf of Lions during winter months were obtained from the meteorological NCEP/NCAR reanalysis dataset and compared with other meteorological data such as surface air temperature. The standardized air temperature anomalies at 1000 hPa in the Gulf of Lions during winter (December–March) has been shown to be the simplest and best indicator of absence/presence of WIW in the Balearic Islands channels in late spring. Values above 1.0 of the standardized temperature anomaly would indicate absence of WIW in the Ibiza Channel. The high correlation obtained with available in-situ oceanographic data allows the use of this index as an indicator of presence of WIW and then of different regional circulation scenarios backwards in time and in those years for which the oceanographic data are missing or scarc

    High hole mobility and light-harvesting in discotic nematic dendrimers prepared: Via 'click' chemistry

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    We report a new family of liquid crystalline porphyrin-core dendrimers with coumarin units at the periphery of the dendrimer. These compounds have been prepared by copper-catalyzed azide-alkyne "click" cycloaddition (CuAAC). The mesomorphic properties have been investigated via polarized optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The peripheral coumarin units play a key role in the liquid crystal behavior, contributing to the appearance of discotic nematic mesophases with hole mobility values among the highest values reported for discotic liquid crystals (of the order of 1 cm 2 V -1 s -1 ). It has also been demonstrated that excitation of the coumarin moieties leads to energy transfer (antenna effect) to the luminescent porphyrin core. Therefore, this strategy, which involves ''click'' chemistry, has been proven to be a powerful and elegant synthetic tool for the preparation of optoelectronic materials based on complex dendritic architectures

    Aircraft icing: in-cloud measurements and sensitivity to physical parameterizations

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    The prediction of supercooled cloud drops in the atmosphere is a basic tool for aviation safety, owing to their contact with and instant freezing on sensitive locations of the aircraft. One of the main disadvantages for predicting atmospheric icing conditions is the acquisition of observational data. In this study, we used in‐cloud microphysics measurements taken during 10 flights of a C‐212 research aircraft under winter conditions, during which we encountered 37 regions containing supercooled liquid water. To investigate the capability of the Weather Research and Forecasting model to detect regions containing supercooled cloud drops, we propose a multiphysics ensemble approach. We used four microphysics and two planetary boundary layer schemes. The Morrison parameterization yielded superior results, whereas the planetary boundary layer schemes were essential in evaluating the presence of liquid water content. The Goddard microphysics scheme best detected the presence of ice water content but tended to underestimate liquid water content

    Flavour physics of the RS model with KK masses reachable at LHC

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    The version of the higher-dimensional Randall-Sundrum (RS) model with matter in the bulk, which addresses the gauge hierarchy problem, has additional attractive features. In particular, it provides an intrinsic geometrical mechanism that can explain the origin of the large mass hierarchies among the Standard Model fermions. Within this context, a good solution for the gauge hierarchy problem corresponds to low masses for the Kaluza-Klein (KK) excitations of the gauge bosons. Some scenarios have been proposed in order to render these low masses (down to a few TeV) consistent with precision electroweak measurements. Here, we give specific and complete realizations of this RS version with small KK masses, down to 1 TeV, which are consistent with the entire structure of the fermions in flavour space: (1) all the last experimental data on quark/lepton masses and mixing angles (including massive neutrinos of Dirac type) are reproduced, (2) flavour changing neutral current constraints are satisfied and (3) the effective suppression scales of non-renormalizable interactions (in the physical basis) are within the bounds set by low energy flavour phenomenology. Our result, on the possibility of having KK gauge boson modes as light as a few TeV, constitutes one of the first theoretical motivations for experimental searches of direct signatures at the LHC collider, of this interesting version of the RS model which accommodates fermion masses.Comment: 27 pages, Latex file. References and comments adde

    Valorization of Cistus ladanifer and Erica arborea shrubs for fuel: Wood and bark thermal characterization

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    As a form of upgraded biomass characterized by its high energy density, low production costs, and low process energy requirements, wood pellets are an environmentally friendly fuel allowing for carbon neutral heating with high energy efficiency. In this work, the suitability of a valorization of the woods from the two most representative shrub species from the Iberian Peninsula (namely Cistus ladanifer and Erica arborea) for heating has been assessed. Whereas Erica arborea met the requirements of ISO 17225-2:2014 for ENplus-B class (the calorific content for both wood and bark was high and not significantly different, and the ash content was permissible for specimens with branch diameter =2, 8 cm), Cistus ladanifer was in the limit of the normative and only met the requirements in terms of acceptable ash percentage (1, 9%) and heating value (19 kJ·g-1) for old specimens with branch diameters > 3, 4 cm. Consequently, while the harvest of E. arborea for its use as fuel does not need to be selective, that of C. ladanifer should be limited to the most robust specimens and foliage should be avoided

    A mesoscale index to describe the regional ocean circulation around the Balearic Islands

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    The formation of Western Mediterranean Intermediate Water (WIW) in the Gulf of Lions and its later presence in the Balearic Channels play a significant role in the regional circulation. The presence of WIW, given by the intermediate water temperatures in the Ibiza Channel, has been related to air temperture in the Gulf of Lions, providing a continuous and long index of regional circulatio
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