5,513 research outputs found
An Approach to Publish Spatial Data on the Web: The GeoLinked Data Case
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
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, -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 pc, and centered at
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 km s. 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
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.
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
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
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
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
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
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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Thermally regulated reversible formation of vesicle-like assemblies by hexaproline amphiphiles
Peptides composed of hexaproline and glutamic acid (P6E) or lysine (P6K) as C-terminal units show thermally promoted aggregation, affording vesicle-like assemblies upon heating to 80 ºC. The aggregation is analyzed by dynamic light scattering (DLS), with number averaged diameters of ca. 600 and 300 nm respectively for P6E and P6K. NMR studies reveal that upon heating the amount of NMR-visible species is reduced to ca. 50% and that an important conformational change is experienced by the molecules in solution. Circular dichroism (CD) shows that at 20º C the peptides present a polyproline II (PP-II) conformation which is disorganized upon heating. Scanning electron microscopy for samples which were fast frozen at 80 ºC reveals vesicle-like assemblies. Using pyrene as a fluorescence probe, a critical aggregation concentration of ca. 30 m was estimated for P6E while that of P6K was above 0.6 mM. The aggregation process is found to be fully reversible and could serve as a basis for development of stimuli responsive carriers
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