1,490 research outputs found
Topological Quintessence
A global monopole (or other topological defect) formed during a recent phase
transition with core size comparable to the present Hubble scale, could induce
the observed accelerating expansion of the universe. In such a model,
topological considerations trap the scalar field close to a local maximum of
its potential in a cosmologically large region of space. We perform detailed
numerical simulations of such an inhomogeneous dark energy system (topological
quintessence) minimally coupled to gravity, in a flat background of initially
homogeneous matter. We find that when the energy density of the field in the
monopole core starts dominating the background density, the spacetime in the
core starts to accelerate its expansion in accordance to a \Lambda CDM model
with an effective inhomogeneous spherical dark energy density parameter
\Omega_\Lambda(r). The matter density profile is found to respond to the global
monopole profile via an anti-correlation (matter underdensity in the monopole
core). Away from the monopole core, the spacetime is effectively
Einstein-deSitter (\Omega_\Lambda(r_{out}) -> 0) while at the center
\Omega_\Lambda(r ~ 0) is maximum. We fit the numerically obtained expansion
rate at the monopole core to the Union2 data and show that the quality of fit
is almost identical to that of \Lambda CDM. Finally, we discuss potential
observational signatures of this class of inhomogeneous dark energy models.Comment: Accepted in Phys. Rev. D (to appear). Added observational bounds on
parameters. 10 pages (two column revtex), 6 figures. The Mathematica files
used to produce the figures of this study may be downloaded from
http://leandros.physics.uoi.gr/topquin
Pan, cereales integrales y salud
El pan es un elemento básico en la alimentación de los seres humanos y constituye la columna vertebradora de la dieta mediterránea. Su relación con la salud es importante, ya que contribuye a satisfacer las necesidades energéticas y puede disminuir factores de riesgo de ciertas patologías crónicas no transmisibles, especialmente cuando el trigo es de grano entero. Esta acción preventiva favorable se ha relacionado con la enfermedad cardiovascular, la diabetes, la obesidad, el cáncer de colon y la diverticulosis intestinal. En esta revisión se analizan los efectos beneficiosos y perjudiciales para la salud de este alimento.
Bread is a basic food item for humans, constituting the backbone of the Mediterranean diet. Its relation to health is important, as it helps to meet energy needs and may reduce risk factors for certain chronic noncommunicable diseases, especially when
wheat is whole grain. This favorable preventative action has been linked to cardiovascular disease, diabetes, obesity, colon cancer and intestinal diverticulosis. This review analyzes the beneficial and detrimental effects on health
Chapter Tactical Communications for Cooperative SAR Robot Missions
This chapter describes how the ICARUS communications (COM) team defined, developed and implemented an integrated wireless communication system to ensure an interoperable and dependable networking capability for both human and robotic search and rescue field teams and crisis managers. It starts explaining the analysis of the requirements and the context of the project, the existing solutions and the design of the ICARUS communication system to fulfil all the project needs. Next, it addresses the implementation process of the required networking capabilities, and finally, it explains how the ICARUS communication system and associated tools have been integrated in the overall mission systems and have been validated to provide reliable communications for real‐time information sharing during search and rescue operations in hostile conditions
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
Comments on SUSY inflation models on the brane
In this paper we consider a class of inflation models on the brane where the
dominant part of the inflaton scalar potential does not depend on the inflaton
field value during inflation. In particular, we consider supernatural
inflation, its hilltop version, A-term inflation, and supersymmetric (SUSY) D-
and F-term hybrid inflation on the brane. We show that the parameter space can
be broadened, the inflation scale generally can be lowered, and still possible
to have the spectral index .Comment: 7 page
G-band Spectral Synthesis in Solar Magnetic Concentrations
Narrow band imaging in the G-band is commonly used to trace the small
magnetic field concentrations of the Sun, although the mechanism that makes
them bright has remained unclear. We carry out LTE syntheses of the G-band in
an assorted set of semi-empirical model magnetic concentrations. The syntheses
include all CH lines as well as the main atomic lines within the band-pass. The
model atmospheres produce bright G-band spectra having many properties in
common with the observed G-band bright points. In particular, the contrast
referred to the quiet Sun is about twice the contrast in continuum wavelengths.
The agreement with observations does not depend on the specificities of the
model atmosphere, rather it holds from single fluxtubes to MIcro-Structured
Magnetic Atmospheres. However, the agreement requires that the real G-band
bright points are not spatially resolved, even in the best observations. Since
the predicted G-band intensities exceed by far the observed values, we foresee
a notable increase of contrast of the G-band images upon improvement of the
angular resolution. According to the LTE modeling, the G-band spectrum emerges
from the deep photosphere that produces the continuum. Our syntheses also
predict solar magnetic concentrations showing up in continuum images but not in
the G-band . Finally, we have examined the importance of the CH
photo-dissociation in setting the amount of G-band absorption. It turns out to
play a minor role.Comment: To appear in ApJ, 554 n2 Jun 20, 33 pages and 9 figure
Evolution of the threshold temperature definition of a heat wave vs. evolution of the minimum mortality temperature: a case study in Spain during the 1983–2018 period
An area of current study concerns analysis of the possible adaptation of the population to heat, based on the temporal evolution of the minimum mortality temperature (MMT). It is important to know how is the evolution of the threshold temperatures (Tthreshold) due to these temperatures provide the basis for the activation of public health prevention plans against high temperatures. The objective of this study was to analyze the temporal evolution of threshold temperatures (Tthreshold) produced in different Spanish regions during the 1983–2018 period and to compare this evolution with the evolution of MMT. The dependent variable used was the raw rate of daily mortality due to natural causes ICD X: (A00-R99) for the considered period. The independent variable was maximum daily temperature (Tmax) during the summer months registered in the reference observatory of each region. Threshold values were determined using dispersion diagrams (annual) of the prewhitened series of mortality temperatures and Tmax. Later, linear fit models were carried out between the different values of Tthreshold throughout the study period, which permitted detecting the annual rate of change in Tthreshold.This research project was funded by the Carlos III Health Institute (ISCIII) under file number ENPY 470/19 and is supported by the Biodiversity Foundation of the Ministry for Ecological Transition and Demographic Challenge, in addition to the research projects ISCIII: ENPY107/18 and ENPY 376/1
Inflection point inflation within supersymmetry
We propose to address the fine tuning problem of inflection point inflation
by the addition of extra vacuum energy that is present during inflation but
disappears afterwards. We show that in such a case, the required amount of fine
tuning is greatly reduced. We suggest that the extra vacuum energy can be
associated with an earlier phase transition and provide a simple model, based
on extending the SM gauge group to SU(3)_C \times SU(2)_L\times U(1)_Y\times
U(1)_{B-L}, where the Higgs field of U(1)_{B-L} is in a false vacuum during
inflation. In this case, there is virtually no fine tuning of the soft SUSY
breaking parameters of the flat direction which serves as the inflaton.
However, the absence of radiative corrections which would spoil the flatness of
the inflaton potential requires that the U(1)_{B-L} gauge coupling should be
small with g_{B-L}\leq 10^{-4}.Comment: 6 pages, 1 figur
Aplicación de los procesos psicológicos básicos en la elaboración de materiales docentes en formación universitaria
Las nuevas herramientas y recursos TIC han facilitado la elaboración de materiales docentes, pero es necesario que se tenga en cuenta la aportación de los procesos psicológicos básicos como facilitadores en la adquisición del conocimiento. El objetivo de este trabajo es diseñar y elaborar materiales docentes innovadores en los que se apliquen los conocimientos del campo de estudio de los procesos psicológicos básicos, que faciliten y potencien el proceso de enseñanza-aprendizaje en formación universitaria y evaluar el grado de satisfacción del alumnado con los materiales desarrollados. Ha participado en nuestro estudio una muestra disponible y significativa de estudiantes matriculados en dos asignaturas de formación básica del Grado en Enfermería y del Grado en Nutrición Humana y Dietética de la Facultad de Ciencias de la Salud de la Universidad de Alicante. Se describen los materiales diseñados y los resultados sobre la satisfacción del alumnado con esta experiencia piloto mediante un cuestionario elaborado ad hoc
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