5,513 research outputs found

    An Approach to Publish Spatial Data on the Web: The GeoLinked Data Case

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    In this paper we report on an ongoing process aimed at publishing hydrographical data on the Web with a Spanish GeoLinked Data Use Case. Moreover, we discuss the process we followed, and propose methodological guidelines for all the activities involved within the process

    Distances and Kinematics of Gould Belt Star-Forming Regions with Gaia DR2 results

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    We present an analysis of the astrometric results from Gaia second data release (DR2) to Young Stellar Objects (YSOs) in star-forming regions related to the Gould Belt. These regions are Barnard 59, Lupus 1 to 4, Chamaeleon I and II, ϵ\epsilon-Chamaeleontis, the Cepheus flare, IC 5146 and Corona Australis. The mean distance to the YSOs in each region are consistent with earlier estimations, though a significant improvement to the final errors was obtained. The mean distances to the star-forming regions were used to fit an ellipsoid of size (358±7)×(316±13)×(70±4)(358\pm7)\times(316\pm13)\times(70\pm4) pc, and centered at (X0,Y0,Z0)=(82±15,39±7,25±4)(X_0,Y_0,Z_0)=(-82\pm15, 39\pm7, -25\pm4) pc, consistent with recently determined parameter of the Gould Belt. The mean proper motions were combined with radial velocities from the literature to obtain the three dimensional motion of the star-forming regions, which are consistent with a general expansion of the Gould Belt. We estimate that this expansion is occurring at a velocity of 2.5±0.12.5\pm0.1 km s1^{-1}. This is the first time that YSOs motions are used to investigate the kinematic of the Gould Belt. As an interesting side result, we also identified stars with large peculiar velocities.Comment: 18 pages, 14 figures, and 5 tables. Accepted for publication in The Astrophysical Journa

    Abordaje de un mal rendimiento académico en estudiante universitaria: Estudio de caso único

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    El mal rendimiento académico es un problema ampliamente extendido entre la población universitaria y uno de los problemas más habituales junto a aquellos relacionados con la ansiedad y las técnicas de estudio. En el Gabinete de Psicología de la Universidad de Jaén tratamos a una estudiante cuyo motivo de consulta es la ansiedad ante los exámenes y el mal rendimiento. En relación a ello, se le aplican diferentes pruebas de evaluación: autorresgistro de hábitos de estudio diseñado desde este Gabinete, Inventario de Ansiedad Rasgo-Estado - STAI- (Spielberger, Gorsuch y Lushene, 1981), Adaptación española del Inventario para la Depresión de Beck—II (BDI-II) (Sanz y cols., 2005) y Cuestionario de Ansiedad ante los exámenes (Valero, 1997). Tras la corrección de dichas pruebas se elabora una intervención con el objetivo de mejorar los hábitos de estudio y, como actividad complementaria, disminuir los niveles de ansiedad. Las actividades que se desarrollan a lo largo de las sesiones son, en primer lugar, el aprendizaje de técnicas de respiración y relajación. Posteriormente, sesiones dedicadas a la adquisición de técnicas de estudio. Por un lado el aprendizaje de la gestión del tiempo, planificación y priorización de las actividades diarias académicas; por otra parte, el aprendizaje de tareas de síntesis de la información como son el subrayado o la elaboración de esquemas que faciliten la comprensión de la materia y el almacenamiento de tal información para su ulterior recuperación en situación de examen. Durante el período de intervención, la usuaria del servicio psicológico del gabinete sigue algunas de las recomendaciones por lo que consigue sutiles logros en planificación de tareas académicas aunque continúa mostrando dificultades en comprensión y síntesis de la información dando lugar a pobres resultados. Se recomienda a la usuaria continuar el entrenamiento en comprensión, tarea que excede de la competencia de este Gabinete de Psicología por lo que se da por concluida la intervención

    Complete Genome Sequence of Pelosinus fermentans JBW45, a Member of a Remarkably Competitive Group of Negativicutes in the Firmicutes Phylum.

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    The genome of Pelosinus fermentans JBW45, isolated from a chromium-contaminated site in Hanford, Washington, USA, has been completed with PacBio sequencing. Nine copies of the rRNA gene operon and multiple transposase genes with identical sequences resulted in breaks in the original draft genome and may suggest genomic instability of JBW45

    Addressed qubit manipulation in radio-frequency dressed lattices

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    Precise control over qubits encoded as internal states of ultracold atoms in arrays of potential wells is a key element for atomtronics applications in quantum information, quantum simulation and atomic microscopy. Here we theoretically study atoms trapped in an array of radio-frequency dressed potential wells and propose a scheme for engineering fast and high-fidelity single-qubit gates with low error due to cross-talk. In this proposal, atom trapping and qubit manipulation relies exclusively on long-wave radiation making it suitable for atom-chip technology. We demonstrate that selective qubit addressing with resonant microwaves can be programmed by controlling static and radio-frequency currents in microfabricated conductors. These results should enable studies of neutral-atom quantum computing architectures, powered by low-frequency electromagnetic fields with the benefit of simple schemes for controlling individual qubits in large ensembles

    Microcavity exciton-polariton mediated Raman scattering: Experiments and theory

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    We studied the intensity of resonant Raman scattering due to optical phonons in a planar II-VI-type semiconductor microcavity in the regime of strong coupling between light and matter. Two different sets of independent experiments were performed at near outgoing resonance with the middle polariton (MP)branch of the cavity. In the first, the Stokes-shifted photons were kept at exact resonance with the MP, varying the photonic or excitonic character of the polariton. In the second, only the incoming light wavelength was varied, and the resonant profile of the inelastic scattered intensity was studied when the system was tuned out of the resonant condition. Taking some matrix elements as free parameters, both independent experiments are quantitatively described by a model which incorporates lifetime effects in both excitons and photons, and the coupling of the cavity photons to the electron-hole continuum. The model is solved using a Green's function approach which treats the exciton-photon coupling nonperturbatively.Comment: 10 pages, 6 figure

    Lagrange-Fedosov Nonholonomic Manifolds

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    We outline an unified approach to geometrization of Lagrange mechanics, Finsler geometry and geometric methods of constructing exact solutions with generic off-diagonal terms and nonholonomic variables in gravity theories. Such geometries with induced almost symplectic structure are modelled on nonholonomic manifolds provided with nonintegrable distributions defining nonlinear connections. We introduce the concept of Lagrange-Fedosov spaces and Fedosov nonholonomic manifolds provided with almost symplectic connection adapted to the nonlinear connection structure. We investigate the main properties of generalized Fedosov nonholonomic manifolds and analyze exact solutions defining almost symplectic Einstein spaces.Comment: latex2e, v3, published variant, with new S.V. affiliatio

    A variational model for fracture and debonding of thin films under in-plane loadings

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    We study fracture and debonding of a thin stiff film bonded to a rigid substrate through a thin compliant layer, introducing a two-dimensional variational fracture model in brittle elasticity. Fractures are naturally distinguished between transverse cracks in the film (curves in 2D) and debonded surfaces (2D planar regions). In order to study the mechanical response of such systems under increasing loads, we formulate a dimension-reduced, rate-independent, irreversible evolution law accounting for both transverse fracture and debonding. We propose a numerical implementation based on a regularized formulation of the fracture problem via a gradient damage functional, and provide an illustration of its capabilities exploring complex crack patterns, showing a qualitative comparison with geometrically involved real life examples. Moreover, we justify the underlying dimension-reduced model in the setting of scalar-valued displacement fields by a rigorous asymptotic analysis using Γ-convergence, starting from the three-dimensional variational fracture (free-discontinuity) problem under precise scaling hypotheses on material and geometric parameters. © 2014 Elsevier Ltd

    Radio-frequency dressed lattices for ultracold alkali atoms

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    Ultracold atomic gases in periodic potentials are powerful platforms for exploring quantum physics in regimes dominated by many-body effects as well as for developing applications that benefit from quantum mechanical effects. Further advances face a range of challenges including the realization of potentials with lattice constants smaller than optical wavelengths as well as creating schemes for effective addressing and manipulation of single sites. In this paper we propose a dressed-based scheme for creating periodic potential landscapes for ultracold alkali atoms with the capability of overcoming such difficulties. The dressed approach has the advantage of operating in a low-frequency regime where decoherence and heating effects due to spontaneous emission do not take place. These results highlight the possibilities of atom-chip technology in the future development of quantum simulations and quantum technologies, and provide a realistic scheme for starting such an exploration
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