2,703 research outputs found
Asedio compasivo: los vericuetos del cuidar
El Alzheimer está en camino de convertirse en uno de los problemas de salud más graves del mundo. Asociado con el aumento del promedio de edad de la población, es una de las enfermedades con mayor impacto sobre todo en las personas afectadas por el mismo, sus parientes cercanos y el sistema de salud y, en general, toda la sociedad. Actualmente no existe cura para esta enfermedad y la velocidad de su desarrollo sigue siendo desconocida, a pesar del largo período existente entre la detección de la enfermedad y la aparición de los primeros síntomas. Por ello los mayores esfuerzos en investigación se han centrado en la detección de la enfermedad en una etapa temprana. Esto nos conduce a un grave problema bioético que se produce en este período, relacionado con la salud y el cuidado familiar, que afecta a la autonomía, la privacidad y la dignidad de las personas diagnosticadas. El abuso puede cometerse en el hogar, en residencias y hospitales, pero se produce de forma distinta en función del lugar, así que deben considerarse variables adicionales a los protocolos ya establecidos respecto al abuso en los hospitales y Comités de Ética, como el asedio compasivo
Recent development in kinetic theory of granular materials: analysis and numerical methods
33 pagesOver the past decades, kinetic description of granular materials has received a lot of attention in mathematical community and applied fields such as physics and engineering. This article aims to review recent mathematical results in kinetic granular materials, especially for those which arose since the last review by Villani on the same subject. We will discuss both theoretical and numerical developments. We will finally showcase some important open problems and conjectures by means of numerical experiments based on spectral methods
Age and mass studies for young star clusters in M31 from SEDs-fit
In this paper, we present photometry for young star clusters in M31, which
are selected from Caldwell et al. These star clusters have been observed as
part of the Beijing--Arizona--Taiwan--Connecticut (BATC) Multicolor Sky Survey
from 1995 February to 2008 March. The BATC images including these star clusters
are taken with 15 intermediate-band filters covering 3000--10000 \AA. Combined
with photometry in the {\sl GALEX} far- and near-ultraviolet, broad-band
, SDSS , and infrared of Two Micron All Sky Survey,
we obtain their accurate spectral energy distributions (SEDs) from 1538-20000
\AA. We derive these star clusters' ages and masses by comparing their SEDs
with stellar population synthesis models. Our results are in good agreement
with previous determinations. The mean value of age and mass of young clusters
( Gyr) is about 385 Myr and , respectively. There
are two distinct peaks in the age distribution, a highest peak at age 60
Myr and a secondary peak around 250 Myr, while the mass distribution shows a
single peak around . A few young star clusters have two-body
relaxation times greater than their ages, indicating that those clusters have
not been well dynamically relaxed and therefore have not established the
thermal equilibrium. There are several regions showing aggregations of young
star clusters around the 10 kpc ring and the outer ring, indicating that the
distribution of the young star clusters is well correlated with M31's
star-forming regions. The young massive star clusters (age Myr and
mass ) show apparent concentration around the ring
splitting region, suggesting a recent passage of a satellite galaxy (M32)
through M31 disk.Comment: Accepted for Publication in AJ, 15 pages, 14 figures and 4 table
Old stellar population synthesis: New age and mass estimates for Mayall II = G1
Mayall II = G1 is one of the most luminous globular clusters (GCs) in M31.
Here, we determine its age and mass by comparing multicolor photometry with
theoretical stellar population synthesis models. Based on far- and
near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHK_s 2MASS
data, we construct the most extensive spectral energy distribution of G1 to
date, spanning the wavelength range from 1538 to 20,000 A. A quantitative
comparison with a variety of simple stellar population (SSP) models yields a
mean age that is consistent with G1 being among the oldest building blocks of
M31 and having formed within ~1.7 Gyr after the Big Bang. Irrespective of the
SSP model or stellar initial mass function adopted, the resulting mass
estimates (of order ) indicate that G1 is one of the most massive
GCs in the Local Group. However, we speculate that the cluster's exceptionally
high mass suggests that it may not be a genuine GC. We also derive that G1 may
contain, on average, far-ultraviolet-bright,
hot, extreme horizontal-branch stars, depending on the SSP model adopted. On a
generic level, we demonstrate that extensive multi-passband photometry coupled
with SSP analysis enables one to obtain age estimates for old SSPs to a similar
accuracy as from integrated spectroscopy or resolved stellar photometry,
provided that some of the free parameters can be constrained independently.Comment: Accepted for Publication in RAA, 12 pages, 1 figure, 2 table
Case 4-2001: acute sarcoidosis
To the Editor: the February 8 Case Record involves a patient with Löfgren's syndrome. In his discussion of the case, Dr. Bates does not sufficiently emphasize the importance of the recognition of periarticular ankle inflammation as a particular presenting sign of acute sarcoidosis. In the Nordic countries and Spain, Löfgren's syndrome is the most common form of the disease and frequently starts with periarticular ankle inflammation. In our series of 186 white patients with Löfgren's syndrome, 35 (19 percent) presented with periarticular ankle inflammation alone and 46 (25 percent) had periarticular ankle inflammation in association with erythema nodosum
Análisis comparativo 'in vitro' de las fisuras apicales producidas por la utilización de las puntas ultrasónicas y el material rotatorio convencional en cirugía periapical
Introducción: El objetivo de este estudio es determinar ·in vitro· si la aparición de las fisuras en la superficie apical se deben a la realización de la apicectomía o a la confección de una caja para obturación retrógrada mediante ultrasonidos o material rotatorio convencional. También se estudian otros factores determinantes en la formación de fisuras apicales. Material y métodos: Se emplearon 81 dientes, 41 de los cuales se conservaron en seco y 40 en hidratación con suero. Se realizó la apicectomía en todas las muestras. En la serie conservada en seco e 41) y en 20 de los dientes hidratados se realizaron las cajas de obturación retrógrada con ultrasonidos y en los restantes con instrumental rotatorio. Se tiñeron las muestras con azul de metileno (0,004%) y se analizaron visualmente las superficies apicales con una lupa óptica. Resultados: Se evidencian 9 fisuras nuevas tras la realización de la caja de obturación, perteneciendo la mayoría (7 de ellas) al grupo de los dientes no hidratados tratados con ultrasonidos. Conclusiones: El uso de ultrasonidos con abundante irrigación y un tiempo máximo de aplicación de 30', permiten realizar adecuadas cajas de obturación sin riesgo de generar fisuras
Dimerization of highly pyramidalized 3,4,8,9-tetramethyltetracyclo[4.4.0.03,9.04,8]dec-1(6)-ene to a hydrocarbon featuring four cyclohexane rings in boat conformation
The synthesis, chemical trapping, and dimerization of a highly pyramidalized alkene is reported. Its dimer is a unique nonacycle featuring three planar cyclobutane rings, four cyclopentane rings, and four cyclohexane rings in boat conformations. The X-ray diffraction analysis showed a H-H distance between the flagpole hydrogen atoms of 1.999 and a separation of 2.619 between the two flagpole carbon atoms. The three cyclobutane rings of the dimer were thermally stabl
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