2,894 research outputs found
INFLUENCE OF PREPARATION PROCESS ON PHYSICAL PROPERTIES AND DEVITRIFICATION OF Li2B2O4 (0,9) LiFe5O8 (0,1) GLASSES
Double roller quenching of Li2B2O4(0.9)-LiFe5O8(0.1) has been performed with various melt temperatures and roller speeds. The changes in physical properties or in the devitrification process of the amorphous samples are shown to be related to the LiFe5O8 content variations or to the Fe2+ appearance but not to structural changes of the amorphous state due to preparation processe
Cosmological perturbations from inhomogeneous preheating and multi-field trapping
We consider inhomogeneous preheating in a multi-field trapping model. The
curvature perturbation is generated by inhomogeneous preheating which induces
multi-field trapping at the enhanced symmetric point (ESP), and results in
fluctuation in the number of e-foldings. Instead of considering simple
reheating after preheating, we consider a scenario of shoulder inflation
induced by the trapping. The fluctuation in the number of e-foldings is
generated during this weak inflationary period, when the additional light
scalar field is trapped at the local maximum of its potential. The situation
may look similar to locked or thermal inflation or even to hybrid inflation,
but we will show that the present mechanism of generating the curvature
perturbation is very different from these others. Unlike the conventional
trapped inflationary scenario, we do not make the assumption that an ESP
appears at some unstable point on the inflaton potential. This assumption is
crucial in the original scenario, but it is not important in the multi-field
model. We also discuss inhomogeneous preheating at late-time oscillation, in
which the magnitude of the curvature fluctuation can be enhanced to accommodate
low inflationary scale.Comment: 18pages, 2 figures, to appear in JHE
Tuned MSSM Higgses as an inflaton
We consider the possibility that the vacuum energy density of the MSSM
(Minimal Supersymmetric Standard Model) flat direction condensate involving the
Higgses H_1 and H_2 is responsible for inflation. We also discuss how the
finely tuned Higgs potential at high vacuum expectation values can realize {\it
cosmologically} flat direction along which it can generate the observed density
perturbations, and after the end of inflation -- the coherent oscillations of
the Higgses reheat the universe with all the observed degrees of freedom,
without causing any problem for the electroweak phase transition.Comment: 6 pages, 5 figure
Hybrid Curvatons from Broken Symmetry
We present a new general mechanism for generating curvature perturbations
after inflation. Our model is based on the simple assumption that a field that
starts to oscillate after inflation has a potential characterized by an
underlying global symmetry that is slightly or badly broken. Inhomogeneous
preheating occurs due to the oscillation with the broken symmetry. Unlike the
traditional curvaton model, we will not identify the curvaton with the
oscillating field. The curvaton is identified with the preheat field that could
be either a scalar, vector, or fermionic field. We introduce an explicit mass
term for the curvaton, which is important for later evolution and the decay.
Our present model represents the simplest example of the hybrid of the
curvatons and inhomogeneous preheating.Comment: 21pages, 5 figures, accepted for publication in JHE
Competencia intercultural en el ámbito de las drogodependencias
En este artículo partimos de una concepción multidimensional o biopsicosocial de las drogodependencias. Dentro de este marco de análisis, abogamos por una mayor visibilización de la dimensión intercultural, ya que es imprescindible para el diseño y desarrollo de procesos de intervención integrales. Proponemos la competencia intercultural como un modelo de trabajo que puede permitir el incremento en las capacidades de instituciones y profesionales, especialmente relevante en el caso de los trabajadores sociales, para abordar eficazmente la dimensión intercultural aludida. Tras una amplia revisión de la literatura científica, hemos definido cinco procesos que pueden contribuir a reforzar la competencia intercultural de una institución y cuatro procesos que pueden contribuir a incrementar la competencia intercultural de un o una profesional. Aunque han sido seleccionados para su aplicación en el ámbito de las drogodependencias, todos estos procesos también pueden servir para mejorar la atención a cualquier otro tipo de persona o grupo culturalmente diverso.
This article takes a multidimensional or biopsychosocial conception of drug dependency as its starting point. Within this analytical framework, we advocate making the intercultural dimension more visible, since it is essential for the design and implementation of integral intervention processes. We propose intercultural competence as a working model that can increase the capacities of institutions and professionals —a particularly important consideration in the case of social work— in order to effectively address the aforementioned cultural dimension. After an extensive review of the scientific literature, we have defined five processes that can contribute to strengthening an institution’s intercultural competence and four processes that can do the same for a professional’s intercultural competence. Though selected for application in the area of drug dependencies, all these processes can also prove useful in improving attention to any other kind of culturally diverse group or person
Inflection point inflation: WMAP constraints and a solution to the fine-tuning problem
We consider observational constraints and fine-tuning issues in a
renormalizable model of inflection point inflation, with two independent
parameters. We derive constraints on the parameter space of this model arising
from the WMAP 7-year power spectrum. It has previously been shown that it is
possible to successfully embed this potential in the MSSM. Unfortunately, to do
this requires severe fine-tuning. We address this issue by introducing a hybrid
field to dynamically uplift the potential with a subsequent smooth phase
transition to end inflation at the necessary point. Large parameter regions
exist where this drastically reduces the fine-tuning required without ruining
the viability of the model. A side effect of this mechanism is that it
increases the width of the slow-roll region of the potential, thus also
alleviating the problem of the fine-tuning of initial conditions. The MSSM
embedding we study has been previously shown to be able to explain the
smallness of the neutrino masses. The hybrid transition does not spoil this
feature as there exist parameter regions where the fine-tuning parameter is as
large as and the neutrino masses remain small.Comment: 12 pages, 2 figures, JCAP style. Version accepted for publication in
JCAP. Modifications made to improve readability, as requested by the referee;
results and conclusions unchanged. References update
- …