7,811 research outputs found
Mean field study of structural changes in Pt isotopes with the Gogny interaction
The evolution of the nuclear shapes along the triaxial landscape is studied
in the Pt isotopic chain using the selfconsistent Hartree-Fock-Bogoliubov
approximation based on the Gogny interaction. In addition to the
parametrization D1S, the new incarnations D1N and D1M of this force are also
included in our analysis to asses to which extent the predictions are
independent of details of the effective interaction. The considered range of
neutron numbers 88<N<26 includes prolate, triaxial, oblate and spherical ground
state shapes and serves for a detailed comparison of the predictions obtained
with the new sets D1N and D1M against the ones provided by the standard
parametrization Gogny-D1S in a region of the nuclear landscape for which
experimental and theoretical fingerprints of shape transitions have been found.
Structural evolution along the Pt chain is discussed in terms of the
deformation dependence of single particle energies.Comment: 18 pages, 10 figures. Accepted for publication in Phys. Rev.
Problemas y propuestas de mejora en la atención sanitaria a los inmigrantes económicos
ResumenObjetivosAnalizar los problemas que existen en la atención sanitaria a los inmigrantes económicos en opinión de profesionales sociosanitarios, de la administración sanitaria y de inmigrantes, así como conocer y priorizar las propuestas de los profesionales para mejorar dicha atención.MétodosEstudio descriptivo de enfoque cualitativo realizado en Mallorca. Se han realizado tres grupos focales y tres grupos nominales con profesionales de atención primaria y especializada, dos entrevistas semiestructuradas a dos miembros de la administración sanitaria, uno de la Administración autonómica y otro de la Administración central, y doce entrevistas semiestructuradas a inmigrantes económicos identificados a partir de informantes clave.ResultadosEl incremento del número de inmigrantes económicos es percibido por los profesionales y por la administración con una sensación de llegada masiva. Los principales problemas identificados han sido las restricciones de acceso, el seguimiento de estos pacientes, y la falta de entrenamiento en medicina tropical. Los inmigrantes, en cambio, están más preocupados por regularizar su situación y por el acceso a la vivienda. La primera propuesta de los profesionales es su formación en medicina tropical. La Administración autonómica prioriza el acceso a los servicios sanitarios y la búsqueda activa de problemas de salud en esta población, mientras que la Administración central aboga en primer lugar por la regularización de todos los inmigrantes.ConclusionesLas principales barreras en la atención sanitaria a los inmmigrantes económicos son, en opinión de los profesionales sociosanitarios, las restricciones de acceso, el seguimiento clínico y la falta de entrenamiento en medicina tropical, y para mejorar esta situación los profesionales demandan formación. Las prioridades de las Administraciones autonómica y central no son coincidentes. Finalmente, para los inmigrantes económicos, la atención sanitaria no parece ser una prioridad.SummaryObjectivesTo analyse existing problems in health care to economic immigrants from the point of view of health and social professionals, health authorities and economic immigrants and to know which will be their proposals and priorities to improve economic immigrants’s health assistance.MethodsQualitative approach study made in Majorca island. (Spain). Three focus groups and three nominal groups with health and social workers from primary health care and hospital services were carried out as well as two partially structured interviews to health authorities, one Autonomic Authority and one Governmental Authority, and twelve partially structured interviews to economic immigrants identified trough key informants.ResultsHealth and social workers perceive the increase in the number of economic immigrants as a massive arrival. The main problems identified are: access restrictions to public helath services for economic immigrants, the follow-up of these patients and diagnostic difficulties because lack of training in tropical medicine. Health and social workers’s first proposal for improving this situation is their own training in tropical medicine. Autonomic Authority priorities are to garantiee access to public health services for all immigrants and to look actively for health problems in these population. Governmental Authority, instead, holds the legalization for all. In fact, economic immigrants are not concerned on health care because legalization and houssing problems.ConclusionsThe main barriers identified by health and social workers in health care to economic immigrants are: access restrictions, follow-up and lack of training in tropical medicine. Health and social first proposal to improve this situation is their own training in tropical medicine while Autonomic and Central Authorities’s priorities are not the same. For economic inmigrants, health assistance is not their biggest concern
Two-level interacting boson models beyond the mean field
The phase diagram of two-level boson Hamiltonians, including the Interacting
Boson Model (IBM), is studied beyond the standard mean field approximation
using the Holstein-Primakoff mapping. The limitations of the usual intrinsic
state (mean field) formalism concerning finite-size effects are pointed out.
The analytic results are compared to numerics obtained from exact
diagonalizations. Excitation energies and occupation numbers are studied in
different model space regions (Casten triangle for IBM) and especially at the
critical points.Comment: 14 pages, 13 figure
The platinum nuclei: concealed configuration mixing and shape coexistence
The role of configuration mixing in the Pt region is investigated. For this
chain of isotopes, the nature of the ground state changes smoothly, being
spherical around mass and and deformed around the
mid-shell N=104 region. This has a dramatic effect on the systematics of the
energy spectra as compared to the systematics in the Pb and Hg nuclei.
Interacting Boson Model with configuration mixing calculations are presented
for gyromagnetic factors, -decay hindrance factors, and isotope shifts.
The necessity of incorporating intruder configurations to obtain an accurate
description of the latter properties becomes evident.Comment: Accepted in Physical Review
Thermal diagnostic of the Optical Window on board LISA Pathfinder
Vacuum conditions inside the LTP Gravitational Reference Sensor must comply
with rather demanding requirements. The Optical Window (OW) is an interface
which seals the vacuum enclosure and, at the same time, lets the laser beam go
through for interferometric Metrology with the test masses. The OW is a
plane-parallel plate clamped in a Titanium flange, and is considerably
sensitive to thermal and stress fluctuations. It is critical for the required
precision measurements, hence its temperature will be carefully monitored in
flight. This paper reports on the results of a series of OW characterisation
laboratory runs, intended to study its response to selected thermal signals, as
well as their fit to numerical models, and the meaning of the latter. We find
that a single pole ARMA transfer function provides a consistent approximation
to the OW response to thermal excitations, and derive a relationship with the
physical processes taking place in the OW. We also show how system noise
reduction can be accomplished by means of that transfer function.Comment: 20 pages, 14 figures; accepted for publication in Class. Quantum Gra
Two-neutron separation energies, binding energies and phase transitions in the interacting boson model
In the framework of the interacting boson model the three transitional
regions (rotational-vibrational, rotational--unstable and,
vibrational--unstable transitions) are reanalyzed. A new kind of plot
is presented for studying phase transitions in finite systems such as atomic
nuclei. The importance of analyzing binding energies and not only energy
spectra and electromagnetic transitions, describing transitional regions is
emphasized. We finally discuss a number of realistic examples.Comment: 34 pages, TeX (ReVTeX). 12 ps figures. 3 tables. Submitted to Nucl.
Phys.
Anomalía congénita del atlas asociada con fractura de la apófisis espinosa de C-7 : a propósito de 1 caso
Se presenta 1 paciente con un defecto congenita del arco posterior del atlas asociado
con una fractura de la apólisis espinosa de C-7. La TAC, precedida de una correcta evaluación
clínica, permiten diferenciar los traumatismos agudos de las anomalías congénitas en el atlas.A case of a congenital cleft of the posterior arch of the atlas associated with a fracture
of the spinous process of C-7 is reported. Appropiate clinical evaluation and CT-scan study
allow to differentiate acute trauma from a congenital abnormality in the atlas
Near-field electromagnetic wave scattering from random self-affine fractal metal surfaces: Spectral dependence of local field enhancements and their statistics in connection with surface-enhanced Raman scattering
11 págs.; 10 figs.By means of rigorous numerical simulation calculations based on the Green's theorem integral equation formulation, we study the near electromagnetic field in the vicinity of very rough, one-dimensional self-affine fractal surfaces of Ag, Au, and Cu (for both vacuum and water propagating media) illuminated by a p-polarized field. Strongly localized enhanced optical excitations (hot spots) are found, with electric field intensity enhancements of close to 4 orders of magnitude and widths below a tenth of the incoming wavelength. These effects are produced by the roughness-induced surface-plasmon polariton excitation. We study the characteristics of these optical excitations as well as other properties of the surface electromagnetic field, such as its statistics (probability density function, average, and fluctuations), and their dependence on the excitation spectrum (in the visible and near-infrared regions). Our study is relevant to the use of self-affine fractals as surface-enhanced Raman scattering substrates, where large local and average field enhancements are desired. ©2000 American Physical SocietyThis work was supported by the Spanish Dirección General
de Ensenñanza Superior e Investigación Científica y Técnica,
through Grant No. PB97-1221. We also thank the
Mexican-Spanish CONACYT-CSIC program for partial
travel support.Peer Reviewe
Phase diagram for a Cubic Consistent-Q Interacting Boson Model Hamiltonian: signs of triaxiality
An extension of the Consistent-Q formalism for the Interacting Boson Model
that includes the cubic QxQxQ term is proposed. The potential energy surface
for the cubic quadrupole interaction is explicitly calculated within the
coherent state formalism using the complete chi-dependent expression for the
quadrupole operator. The Q-cubic term is found to depend on the asymmetry
deformation parameter gamma as a linear combination of cos(3gamma) and
cos^2(3\gamma) terms, thereby allowing for triaxiality. The phase diagram of
the model in the large N limit is explored, it is described the order of the
phase transition surfaces that define the phase diagram, and moreover, the
possible nuclear equilibrium shapes are established. It is found that, contrary
to expectations, there is only a very tiny region of triaxiality in the model,
and that the transition from prolate to oblate shapes is so fast that, in most
cases, the onset of triaxiality might go unnoticed.Comment: 18 pages, 19 figure
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