652 research outputs found

    Rank two quadratic pairs and surface group representations

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    Let XX be a compact Riemann surface. A quadratic pair on XX consists of a holomorphic vector bundle with a quadratic form which takes values in fixed line bundle. We show that the moduli spaces of quadratic pairs of rank 2 are connected under some constraints on their topological invariants. As an application of our results we determine the connected components of the SO0(2,3)\mathrm{SO}_0(2,3)-character variety of XX.Comment: 37 pages, 1 figur

    Maximal surface group representations in isometry groups of classical Hermitian symmetric spaces

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    Higgs bundles and non-abelian Hodge theory provide holomorphic methods with which to study the moduli spaces of surface group representations in a reductive Lie group G. In this paper we survey the case in which G is the isometry group of a classical Hermitian symmetric space of non-compact type. Using Morse theory on the moduli spaces of Higgs bundles, we compute the number of connected components of the moduli space of representations with maximal Toledo invariant.Comment: v2: added due credits to the work of Burger, Iozzi and Wienhard. v3: corrected count of connected components for G=SU(p,q) (p \neq q); added due credits to the work of Xia and Markman-Xia; minor corrections and clarifications. 31 page

    Thermal hysteresis of microwave loss in (La1-xPrx)(0.7)Ca 0.3MnO3 films

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    [EN] We have measured the temperature (T) dependencies of the dc resistances (R-dc) and the microwave loss (R-muw) in a variety of samples of (La1-xPrx)(0.7)Ca0.3MnO3 while varying x from 0 to 0.4. Whereas both the sets of data exhibit maxima, the ac loss peak is much flatter and, during cooling, appears at a much lower temperature than the peak temperature in R-dc. The discrepancy, which vanishes for x=0, increases with lowering tolerance factor (t) (or increasing x). Also R-muw vs T exhibits large thermal hysteresis for x=0.4 indicating that the transition is first order. Cooling in a magnetic field of 9 kOe causes an upward shift of about 20 K in the R-muw peak, in some of the x=0.4 films, yielding a large magnetoimpedance. Further, once these films are exposed to a magnetic field at low T, they fail to recover their virginal behavior on subsequent cooling from room T. These films could be brought to their original state by annealing at high T. The discrepancy between R-dc and R-muw implies that the system is inhomogeneous at low T, providing, for the first time, microwave absorption evidence that manganites exhibit multiphase behavior. Presumably, disorder and strain (increasing with x) combine to stabilize a mixed phase. (C) 2002 American Institute of Physics.S77367738911

    Examining mindfulness and moral disengagement in doping: Perspective of Turkish wrestlers

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    Introduction: Studies related to attitudes toward the use of prohibited substances in Turkish athletes are scarce. The World Anti-Doping Agency (WADA) has implemented anti-doping educational policies emphasizing doping-related education in studies conducted among Turkish wrestlers. However, it is still unclear the extent to which the wrestlers comply and adhere to these anti-doping policies. No research has previously examined the effect of anti-doping education on athletes' mindfulness and moral disengagement in doping (MDD). Therefore, the present study has a two-fold objective: first, to examine whether doping-related education (DRE) and the status of being a national athlete (NA) have an effect on athlete mindfulness and MDD. Second, to analyze the relationship between each sub-dimensions of athlete mindfulness: awareness (ASD), judgment (JSD), and refocus (RSD) with MDD. Methods: A total of 409 male wrestlers participated in this study. MANOVA analysis showed that NA and DRE alone have no effect on MDD but have a general effect on mindfulness. Results: The highest effect was on the ASD of being an NA ((Formula presented.) = 0.173). When the interaction effect of NA*DRE was examined, significant difference in MDD (F = 8.218, p = 0.004), ASD (F = 8.476, p = 0.004), JSD (F = 5.844, p = 0.016), and RSD (F = 11.476, p = 0.001) were found. MDD has a weak negative relationship with ASD (r = ?0.126) and RSD (r = ?0.041) and a weak positive relationship with the JSD sub-dimension (r = 0.140). Those results suggest that being a NA and having received anti-doping education affect moral disengagement in doping and athletes' mindfulness. Discussion: As a conclusion, it is recommended to increase awareness and anti-doping education among national-standard Turkish wrestlers to prevent them from engaging in doping behaviors. Copyright © 2023 Ayyıldız, Kayabeşler, Gülü, Yagin, Aldhahi, García-Grimau and Al-Mhanna.Princess Nourah Bint Abdulrahman University, PNU: PNURSP2023R 286This research was funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2023R 286), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

    Mindfulness Training Improves Quality of Life and Reduces Depression and Anxiety Symptoms Among Police Officers: Results From the POLICE Study—A Multicenter Randomized Controlled Trial

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    Background: Police officers'' high-stress levels and its deleterious consequences are raising awareness to an epidemic of mental health problems and quality of life (QoL) impairment. There is a growing evidence that mindfulness-based interventions are efficacious to promote mental health and well-being among high-stress occupations. Methods: The POLICE study is a multicenter randomized controlled trial (RCT) with three assessment points (baseline, post-intervention, and 6-month follow-up) where police officers were randomized to mindfulness-based health promotion (MBHP) (n = 88) or a waiting list (n = 82). This article focuses on QoL, depression and anxiety symptoms, and religiosity outcomes. Mechanisms of change and MBHP feasibility were evaluated. Results: Significant group × time interaction was found for QoL, depression and anxiety symptoms, and non-organizational religiosity. Between-group analysis showed that MBHP group exhibited greater improvements in QoL, and depression and anxiety symptoms at both post-intervention (QoL d = 0.69 to 1.01; depression d = 0.97; anxiety d = 0.73) and 6-month follow-up (QoL d = 0.41 to 0.74; depression d = 0.60; anxiety d = 0.51), in addition to increasing non-organizational religiosity at post-intervention (d = 0.31). Changes on self-compassion mediated the relationship between group and pre-to-post changes for all QoL domains and facets. Group effect on QoL overall health facet at post-intervention was moderated by mindfulness trait and spirituality changes. Conclusion: MBHP is feasible and efficacious to improve QoL, and depression and anxiety symptoms among Brazilian officers. Results were maintained after 6 months. MBHP increased non-organizational religiosity, although the effect was not sustained 6 months later. To our knowledge, this is the first mindfulness-based intervention RCT to empirically demonstrate these effects among police officers. Self-compassion, mindfulness trait, and spirituality mechanisms of change are examined. Clinical Trial Registration: www.ClinicalTrials.gov. identifier: NCT03114605.

    Symmetric hyperbolic systems for a large class of fields in arbitrary dimension

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    Symmetric hyperbolic systems of equations are explicitly constructed for a general class of tensor fields by considering their structure as r-fold forms. The hyperbolizations depend on 2r-1 arbitrary timelike vectors. The importance of the so-called "superenergy" tensors, which provide the necessary symmetric positive matrices, is emphasized and made explicit. Thereby, a unified treatment of many physical systems is achieved, as well as of the sometimes called "higher order" systems. The characteristics of these symmetric hyperbolic systems are always physical, and directly related to the null directions of the superenergy tensor, which are in particular principal null directions of the tensor field solutions. Generic energy estimates and inequalities are presented too.Comment: 24 pages, no figure

    Non-Abelian Vortices on Riemann Surfaces: an Integrable Case

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    We consider U(n+1) Yang-Mills instantons on the space \Sigma\times S^2, where \Sigma is a compact Riemann surface of genus g. Using an SU(2)-equivariant dimensional reduction, we show that the U(n+1) instanton equations on \Sigma\times S^2 are equivalent to non-Abelian vortex equations on \Sigma. Solutions to these equations are given by pairs (A,\phi), where A is a gauge potential of the group U(n) and \phi is a Higgs field in the fundamental representation of the group U(n). We briefly compare this model with other non-Abelian Higgs models considered recently. Afterwards we show that for g>1, when \Sigma\times S^2 becomes a gravitational instanton, the non-Abelian vortex equations are the compatibility conditions of two linear equations (Lax pair) and therefore the standard methods of integrable systems can be applied for constructing their solutions.Comment: 8 pages; v2: typos fixe

    Measurement of a 2D fast-ion velocity distribution function by tomographic inversion of fast-ion D-alpha spectra

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    We present the first measurement of a local fast-ion 2D velocity distribution function f(v||, v⊥). To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion Dα (FIDA) light from the plasma centre in three views simultaneously. The measured spectra agree very well with synthetic spectra calculated from a TRANSP/NUBEAM simulation. Based on the measured FIDA spectra alone, we infer f(v||, v⊥) by tomographic inversion. Salient features of our measurement of f(v||, v⊥) agree reasonably well with the simulation: the measured as well as the simulated f(v||, v⊥) are lopsided towards negative velocities parallel to the magnetic field, and they have similar shapes. Further, the peaks in the simulation of f(v||, v⊥) at full and half injection energies of the neutral beam also appear in the measurement at similar velocity-space locations. We expect that we can measure spectra in up to seven views simultaneously in the next ASDEX Upgrade campaign which would further improve measurements of f(v||, v⊥) by tomographic inversion

    Present status of IGEX dark matter search at Canfranc Underground Laboratory

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    One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion plot has been derived for WIMP-nucleon spin-independent interactions. To obtain this result, 40 days of data from the IGEX detector (energy threshold 4 keV), recently collected, have been analyzed. These data improve the exclusion limits derived from all the other ionization germanium detectors in the mass region from 20 GeV to 200 GeV, where a WIMP supposedly responsible for the annual modulation effect reported by the DAMA experiment would be located. The new IGEX exclusion contour enters, by the first time, the DAMA region by using only raw data, with no background discrimination, and excludes its upper left part. It is also shown that with a moderate improvement of the detector performances, the DAMA region could be fully explored.Comment: 3 pages, 3 figures, talk delivered at the 7th International Workshop on Topics in Astroparticle and Underground Physics (TAUP 2001), September 2001, Laboratori Nazionali del Gran Sasso, Italy (to appear in the Conference Proceedings, Nucl. Phys. B (Proc. Suppl.)

    Utilización de materiales naturales y reciclados para alcanzar edificios de energía casi nula. Proyecto Life Renatural NZEB

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    CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: El proyecto LIFE ReNatural NZEB promueve el uso de nuevos materiales de construcción naturales y reciclados para alcanzar edificios de Consumo de Energía Casi Nulo con baja huella de carbono, en España y Portugal. El proyecto plantea cuatro fases principales de ensayo y demostración: caracterización básica de materiales naturales, caracterización técnica y mecánica de materiales y productos de construcción, ensayos a escala real en los demostradores EDEA, y experiencias de demostración: construcción de cuatro nuevas viviendas sociales en Ribera del Fresno (Badajoz); rehabilitación de un bloque de 16 viviendas sociales en el barrio de San Lázaro de Mérida; rehabilitación de cuatro viviendas sociales en el barrio de Santa Engracia de Badajoz; y rehabilitación de un edificio de uso público en La Bazana (Badajoz).ABSTRACT: The LIFE ReNatural NZEB project promotes the use of new natural and recycled construction materials to achieve Nearly Zero Energy Buildings with low carbon footprint, in Spain and Portugal. The project involves four main phases of testing and demonstration: basic characterization of natural materials, technical and mechanical characterization of construction materials and products, test of technologies in EDEA’s real-scale construction laboratory, and demonstration projects: construction of four new social housing in Ribera del Fresno (Badajoz); rehabilitation of one block of 16 social housing in the neighborhood of San Lázaro, in Mérida; rehabilitation of four social housing in the neighborhood of Santa Engracia, in Badajoz; and rehabilitation of one public building in La Bazana (Badajoz).info:eu-repo/semantics/publishedVersio
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