531 research outputs found

    New evidence of recent fracturing at the relay zone between the Concud and Teruel faults (eastern Iberian Chain)

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    The NW-SE to NNW-SSE striking Concud Fault and the N-S striking Teruel Fault are extensional structures showing a right relay arrangement. The hectometre-scale offset produced by both structures in the Neogene materials of the Teruel basin is transferred to each other by means of a relay ramp dipping towards NNW. In this study we present new information on recent (Late Pleistocene) brittle deformation structures, some of them located within the relay zone and others aligned with the northwards prolongation of the Teruel Fault. The observed faults and fractures are mostly parallel to the major faults (NNW-SSE), while signs of transverse structures (pointing to hard linkage) are negligible. The Concud and Teruel faults are independent structures from the geometrical and kinematical point of view, but we interpret that there is a mechanical interaction between them, a previous stage to linkage by hypothetical future northwards propagation of the Teruel fault. a Falla de Concud (NW-SE a NNW-SSE) y la Falla de Teruel (N-S) son fallas extensionales dispuestas en relevo diestro. El salto de escala hectométrica que ambas estructuras producen en los materiales neógenos de la fosa de Teruel se transfiere de una a otra mediante una rampa de relevo con pendiente hacia el NNW. En este trabajo se presenta nueva información sobre estructuras frágiles recientes (Pleistoceno Superior), algunas localizadas dentro de la zona de relevo y otras alineadas con la prolongación septentrional de la falla de Teruel. Las fallas y fracturas observadas son en su mayoría paralelas a las fallas mayores (NNW-SSE), mientras que los indicios de estructuras transversales (que podrían apuntar a una ‘conexión dura’ entre las fallas de Concud y Teruel) son muy escasos. Ambas fallas son independientes desde el punto de vista geométrico y cinemático, pero interpretamos que interactúan mecánicamente, en un estadio previo a la coalescencia por una hipotética futura propagación hacia el norte de la falla de Teruel

    Can Activity Worthwhileness Explain OCB-I Change? The Mediating Role of Positive Emotions

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    The competitiveness of today's markets requires employees to do more than is formally expected from them by collaborating with others to benefit the organization (e.g., organizational citizenship behavior focused on individuals, OCB-I). Based on the idea that eudaimonic wellbeing positively influences OCB-I, and considering that positive emotions lead to optimal functioning and important work outcomes, this study analyzes the mediating role of positive emotions in the relationship between activity worthwhileness and OCB-I. Results of hierarchical regressions in a two-wave longitudinal study with a sample of 108 white collar employees show that activity worthwhileness indirectly (but not directly) explains change in OCB-I through positive emotions. Therefore, when it comes to improving performance in the workplace, investment in both hedonic and eudaimonic wellbeing contributes to more effectively benefitting both employees and organizations

    Spin precession and inverted Hanle effect in a semiconductor near a finite-roughness ferromagnetic interface

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    Although the creation of spin polarization in various non-magnetic media via electrical spin injection from a ferromagnetic tunnel contact has been demonstrated, much of the basic behavior is heavily debated. It is reported here for semiconductor/Al2O3/ferromagnet tunnel structures based on Si or GaAs that local magnetostatic fields arising from interface roughness dramatically alter and even dominate the accumulation and dynamics of spins in the semiconductor. Spin precession in the inhomogeneous magnetic fields is shown to reduce the spin accumulation up to tenfold, and causes it to be inhomogeneous and non-collinear with the injector magnetization. The inverted Hanle effect serves as experimental signature. This interaction needs to be taken into account in the analysis of experimental data, particularly in extracting the spin lifetime and its variation with different parameters (temperature, doping concentration). It produces a broadening of the standard Hanle curve and thereby an apparent reduction of the spin lifetime. For heavily doped n-type Si at room temperature it is shown that the spin lifetime is larger than previously determined, and a new lower bound of 0.29 ns is obtained. The results are expected to be general and occur for spins near a magnetic interface not only in semiconductors but also in metals, organic and carbon-based materials including graphene, and in various spintronic device structures.Comment: Final version, with text restructured and appendices added (25 pages, 9 figures). To appear in Phys. Rev.

    Consumer Demand for Environmental, Social, and Ethical Information in Fishery and Aquaculture Product Labels

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    Customers’ attention to sustainability labels in fishery and aquaculture products (FAPs) has been increasing in the last decades, and the industry has adapted to this growing interest by adopting fish ecolabels. However, there is a growing interest to widen the sustainability concept to include the social and ethical information of the fishery and aquaculture industry and to go further from the voluntary approach on the labeling of these aspects in FAPs. For this reason, using data from 2021 Eurobarometer and using machine learning techniques, we disentangle the characteristics of the FAP buyers that consider the importance of environmental impact, ethical, and social information appearing on FAP labeling. The results confirmed that most of the consumers who consider environmental, social, and ethical aspects when buying FAPs also think that this information should be labeled. In line with other works, young, educated, and environmentally aware consumers in high-income countries are more likely to request this information in the FAP label. One interesting finding of the study relates with the asymmetric impact of the variables and the important group of respondents who do not consider these aspects but also advocate to include them in the FAP label. The study outcomes can be beneficial for policymakers to design future public policies regarding FAP labeling, as well as to be taken into consideration in the marketing policies of fishery and aquaculture producers and retailers

    TREX-DM: a low background Micromegas-based TPC for low-mass WIMP detection

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    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass \sim0.3 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This work describes the commissioning of the actual setup situated in a laboratory on surface and the updates needed for a possible physics run at the Canfranc Underground Laboratory (LSC) in 2016. A preliminary background model of TREX-DM is also presented, based on a Geant4 simulation, the simulation of the detector's response and two discrimination methods: a conservative muon/electron and one based on a neutron source. Based on this background model, TREX-DM could be competitive in the search for low-mass WIMPs. In particular it could be sensitive, e.g., to the low-mass WIMP interpretation of the DAMA/LIBRA and other hints in a conservative scenario.Comment: Proceedings of the XIV International Conference on Topics in Astroparticle and Underground Physics (TAUP 2015), 7-11 September 2015, Torino, Ital

    Production of Low-Carbon Magnetic Steel for the LHC Superconducting Dipole and Quadrupole Magnets

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    In 1996 CERN negotiated a contract with Cockerill Sambre â ARCELOR Group for the supply of 50 000 tonnes of low-carbon steel for the LHC main magnets: this was the first contract to be placed for the project, and one of the single largest. In 2005 â after nine years of work â the contract is being successfully completed. This paper describes the steel specifically developed, known as MAGNETILâ¢, its manufacturing and quality control process, organization of production, logistics and contract follow-up. Extensive statistics have been collected relating to physical, mechanical and technological parameters. Specific attention is dedicated to magnetic measurements (coercivity and permeability) performed at both room and cryogenic temperatures, the equipment used and statistical results. Reference is also made to the resulting precision of the fineblanked laminations used for the magnet yoke. The technology transfer from the particle accelerator domain to industry is ongoing, for example for the screening of high voltage cables buried in the ground

    New Marker of Colon Cancer Risk Associated with Heme Intake: 1,4-Dihydroxynonane Mercapturic Acid

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    Background: Red meat consumption is associated with an increased risk of colon cancer. Animal studies show that heme, found in red meat, promotes preneoplastic lesions in the colon, probably due to the oxidative properties of this compound. End products of lipid peroxidation, such as 4-hydroxynonenal metabolites or 8-iso-prostaglandin-F2 (8-iso-PGF2), could reflect this oxidative process and could be used as biomarkers of colon cancer risk associated with heme intake. Methods: We measured urinary excretion of 8-iso-PGF2 and 1,4-dihydroxynonane mercapturic acid (DHN-MA), the major urinary metabolite of 4-hydroxynonenal, in three studies. In a short-term and a carcinogenesis long-term animal study, we fed rats four different diets (control, chicken, beef, and blood sausage as a high heme diet). In a randomized crossover human study, four different diets were fed (a 60 g/d red meat baseline diet, 120 g/d red meat, baseline diet supplemented with heme iron, and baseline diet supplemented with non-heme iron). Results: DHN-MA excretion increased dramatically in rats fed high heme diets, and the excretion paralleled the number of preneoplastic lesions in azoxymethane initiated rats (P < 0.0001). In the human study, the heme supplemented diet resulted in a 2-fold increase in DHN-MA (P < 0.001). Urinary 8-iso-PGF2 increased moderately in rats fed a high heme diet (P < 0.0001), but not in humans. Conclusion: Urinary DHN-MA is a useful noninvasive biomarker for determining the risk of preneoplastic lesions associated with heme iron consumption and should be further investigated as a potential biomarker of colon cancer risk. (Cancer Epidemiol Biomarkers Prev 2006;15(11):2274–9

    Size quantization of Dirac fermions in graphene constrictions

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    Quantum point contacts (QPCs) are cornerstones of mesoscopic physics and central building blocks for quantum electronics. Although the Fermi wave-length in high-quality bulk graphene can be tuned up to hundreds of nanometers, the observation of quantum confinement of Dirac electrons in nanostructured graphene systems has proven surprisingly challenging. Here we show ballistic transport and quantized conductance of size-confined Dirac fermions in lithographically-defined graphene constrictions. At high charge carrier densities, the observed conductance agrees excellently with the Landauer theory of ballistic transport without any adjustable parameter. Experimental data and simulations for the evolution of the conductance with magnetic field unambiguously confirm the identification of size quantization in the constriction. Close to the charge neutrality point, bias voltage spectroscopy reveals a renormalized Fermi velocity (vF1.5×106m/sv_F \approx 1.5 \times 10^6 m/s) in our graphene constrictions. Moreover, at low carrier density transport measurements allow probing the density of localized states at edges, thus offering a unique handle on edge physics in graphene devices.Comment: 24 pages including 20 figures and 1 table. Corrected typos. To appear in Nature Communication

    Block hybrid multilevel method to compute the dominant lambda-modes of the neutron diffusion equation

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    [EN] The dominant lambda-modes associated with a nuclear reactor configuration describe the neutron steady-state distribution and its criticality. Furthermore, they are useful to develop modal methods to study reactor instabilities. Different eigenvalues solvers have been successfully used to obtain such modes, most of them are implemented reducing the original generalized eigenvalue problem to an ordinary one. Thus, it is necessary to solve many linear systems making these methods not very efficient, especially for large problems. In this work, the original generalized eigenvalue problem is considered and two block iterative methods to solve it are studied: the block inverse-free preconditioned Arnoldi method and the modified block Newton method. All of these iterative solvers are initialized using a block multilevel technique. A hybrid multilevel method is also proposed based on the combination of the methods proposed. Two benchmark problems are studied illustrating the convergence and the competitiveness of the methods proposed. A comparison with the Krylov-Schur method and the Generalized Davidson is also included.This work has been partially supported by Spanish Ministerio de Economia y Competitividad under projects ENE2017-89029-P, MTM2017-85669-P and BES-2015-072901.Carreño, A.; Vidal-Ferràndiz, A.; Ginestar Peiro, D.; Verdú Martín, GJ. (2018). Block hybrid multilevel method to compute the dominant lambda-modes of the neutron diffusion equation. Annals of Nuclear Energy. 121:513-524. https://doi.org/10.1016/j.anucene.2018.08.010S51352412
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