6,693 research outputs found
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HerĂ©ticos, liberales y filĂłlogos: la labor lingĂĽĂstica de los heterodoxos decimonĂłnicos en Inglaterra
Reactions induced by Be in a four-body continuum-discretized coupled-channels framework
We investigate the elastic scattering of Be on Pb at beam
energies above (50 MeV) and below (40 MeV) the Coulomb barrier. The reaction is
described within a four-body framework using the Continuum-Discretized
Coupled-Channels (CDCC) method. The Be projectile states are generated
using the analytical Transformed Harmonic Oscillator (THO) basis in
hyperspherical coordinates. Our calculations confirm the importance of
continuum effects at low energies.Comment: 2 pages, 1 figure. Proceedings of the International Scientific
Meeting on Nuclear Physics, RABIDA15, La R\'abida (Spain), June 1-5, 201
Analytical transformed harmonic oscillator basis for three-body nuclei of astrophysical interest: Application to 6He
Recently, a square-integrable discrete basis, obtained performing a simple
analytical local scale transformation to the harmonic oscillator basis, has
been proposed and successfully applied to study the properties of two-body
systems. Here, the method is generalized to study three-body systems. To test
the goodness of the formalism and establish its applicability and limitations,
the capture reaction rate for the nucleosynthesis of the Borromean nucleus 6He
(4He + n + n) is addressed. Results are compared with previous publications and
with calculations based on actual three-body continuum wave functions, which
can be generated for this simple case. The obtained results encourage the
application to other Borromean nuclei of astrophysical interest such as 9Be and
12C, for which actual three-body continuum calculations are very involved.Comment: Accepted in Phys. Rev.
Stellar laboratories. V. The Xe VI ultraviolet spectrum and the xenon abundance in the hot DO-type white dwarf RE0503-289
For the spectral analysis of spectra of hot stars with a high resolution and
high signal-to-noise ratio (S/N), advanced non-local thermodynamic equilibrium
(NLTE) model atmospheres are mandatory. These are strongly dependent on the
reliability of the atomic data that are used for their calculation.
Reliable Xe VI oscillator strengths are used to identify Xe lines in the
ultraviolet spectrum of the DO-type white dwarf RE0503-289 and to determine its
photospheric Xe abundance.
We publish newly calculated oscillator strengths that are based on a recently
measured Xe VI laboratory line spectrum. These strengths were used to consider
their radiative and collisional bound-bound transitions in detail in our NLTE
stellar-atmosphere models to analyze Xe VI lines exhibited in high-resolution
and high S/N UV observations of RE0503-289.
We identify three hitherto unknown Xe VI lines in the ultraviolet spectrum of
RE0503-289 and confirm the previously measured photospheric Xe abundance of
this white dwarf (log Xe = -4.2 +/- 0.6).
Reliable measurements and calculations of atomic data are prerequisite for
stellar-atmosphere modeling. Observed Xe VI line profiles in the ultraviolet
spectrum of the white dwarf RE0503-289 were well reproduced with the newly
calculated Xe VI oscillator strengths.Comment: 3 pages, 4 figure
Efficient numerical schemes for viscoplastic avalanches. Part 2: the 2D case
This paper deals with the numerical resolution of a shallow water viscoplastic flow model. Viscoplastic materials are characterized by the existence of a yield stress: below a certain critical threshold in the imposed stress, there is no deformation and the material behaves like a rigid solid, but when that yield value is exceeded, the material flows like a fluid. In the context of avalanches, it means that after going down a slope, the material can stop and its free surface has a non-trivial shape, as opposed to the case of water (Newtonian fluid). The model involves variational inequalities associated with the yield threshold: finite volume schemes are used together with duality methods (namely Augmented Lagrangian and Bermúdez–Moreno) to discretize the problem. To be able to accurately simulate the stopping behavior of the avalanche, new schemes need to be designed, involving the classical notion of well-balancing. In the present context, it needs to be extended to take into account the viscoplastic nature of the material as well as general bottoms with wet/dry fronts which are encountered in geophysical geometries. Here we derive such schemes in 2D as the follow up of the companion paper treating the 1D case. Numerical tests include in particular a generalized 2D benchmark for Bingham codes (the Bingham–Couette flow with two non-zero boundary conditions on the velocity) and a simulation of the avalanche path of Taconnaz in Chamonix—Mont-Blanc to show the usability of these schemes on real topographies from digital elevation models (DEM)
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El Proyecto Aimhigher, un ejemplo de iniciativa para promover el desarrollo de la competencia intercultural y lingĂĽĂstica en alumnos de FormaciĂłn Profesional en Inglaterra
En este trabajo intentamos dar a conocer los logros y
actividades de una experiencia de colaboraciĂłn entre una
institución dedicada a la enseñanza pública superior a
distancia, The Open University, y Thanet College, un centro
de formaciĂłn profesional en la regiĂłn de Kent, al sureste de
Inglaterra. El objetivo de esta iniciativa fue promover la competencia intercultural y lingĂĽĂstica entre alumnos de
hostelerĂa y con ello recalcar la importancia del aprendizaje de lenguas y culturas en la formaciĂłn profesional. Esta iniciativa se llevĂł a cabo en el 2008 y formĂł parte del Aimhigher Kent and Medway Languages Project
(http://www.languagesgroupproject.org/) un proyecto financiado por la agencia estatal, Aimghigher Kent and Medway (http://www.aimhigherkentandmedway.org/), organismo patrocinador de proyectos educativos y profesionales para jĂłvenes en zonas de bajo nivel socioeconĂłmico en la regiĂł
Insights into the relationship between inherent materials properties of PZT and photochemistry for the development of nanostructured silver.
Recently there has been great interest in using patterned ferroelectric
materials for the photochemical growth of metal nanostructures. Variations in
surface and sub-surface structure influence the photochemical processes. Here we
show that crystallography, and hence remnant polarization, of the ferroelectric
affects photo-deposition. The ratio of metal growth on c– and c+ domains varies
from 1 : 2 for [100] to 1 : 100 for [111]. This is shown to be dependent on the
variations in the band structu
Simultaneous analysis of elastic scattering and transfer/breakup channels for the 6He+208Pb reaction at energies near the Coulomb barrier
The elastic and alpha-production channels for the 6He+208Pb reaction are
investigated at energies around the Coulomb barrier (E_{lab}=14, 16, 18, 22,
and 27 MeV). The effect of the two-neutron transfer channels on the elastic
scattering has been studied within the Coupled-Reaction-Channels (CRC) method.
We find that the explicit inclusion of these channels allows a simultaneous
description of the elastic data and the inclusive alpha cross sections at
backward angles. Three-body Continuum-Discretized Coupled-Channels (CDCC)
calculations are found to reproduce the elastic data, but not the
transfer/breakup data. The trivially-equivalent local polarization potential
(TELP) derived from the CRC and CDCC calculations are found to explain the
features found in previous phenomenological optical model calculations for this
system.Comment: 7 pages, 6 figures (replaced with updated version
Daily Scheduled High Fat Meals Moderately Entrain Behavioral Anticipatory Activity, Body Temperature, and Hypothalamic c-Fos Activation
When fed in restricted amounts, rodents show robust activity in the hours preceding expected meal delivery. This process, termed food anticipatory activity (FAA), is independent of the light-entrained clock, the suprachiasmatic nucleus, yet beyond this basic observation there is little agreement on the neuronal underpinnings of FAA. One complication in studying FAA using a calorie restriction model is that much of the brain is activated in response to this strong hunger signal. Thus, daily timed access to palatable meals in the presence of continuous access to standard chow has been employed as a model to study FAA in rats. In order to exploit the extensive genetic resources available in the murine system we extended this model to mice, which will anticipate rodent high fat diet but not chocolate or other sweet daily meals (Hsu, Patton, Mistlberger, and Steele; 2010, PLoS ONE e12903). In this study we test additional fatty meals, including peanut butter and cheese, both of which induced modest FAA. Measurement of core body temperature revealed a moderate preprandial increase in temperature in mice fed high fat diet but entrainment due to handling complicated interpretation of these results. Finally, we examined activation patterns of neurons by immunostaining for the immediate early gene c-Fos and observed a modest amount of entrainment of gene expression in the hypothalamus of mice fed a daily fatty palatable meal
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