10,143 research outputs found
Multilingual Information Framework for Handling textual data in Digital Media
This document presents MLIF (Multi Lingual Information Framework), a high-level model for describing multilingual data across a wide range of possible applications in the translation/localization process within several multimedia domains (e.g. broadcasting interactive programs within a multilingual community)
Giant magnetic anisotropy at nanoscale: overcoming the superparamagnetic limit
It has been recently observed for palladium and gold nanoparticles, that the
magnetic moment at constant applied field does not change with temperature over
the range comprised between 5 and 300 K. These samples with size smaller than
2.5 nm exhibit remanence up to room temperature. The permanent magnetism for so
small samples up to so high temperatures has been explained as due to blocking
of local magnetic moment by giant magnetic anisotropies. In this report we
show, by analysing the anisotropy of thiol capped gold films, that the orbital
momentum induced at the surface conduction electrons is crucial to understand
the observed giant anisotropy. The orbital motion is driven by localised charge
and/or spin through spin orbit interaction, that reaches extremely high values
at the surfaces. The induced orbital moment gives rise to an effective field of
the order of 103 T that is responsible of the giant anisotropy.Comment: 15 pages, 2 figures, submitted to PR
Extended WKB method, resonances and supersymmetric radial barriers
Semiclassical approximations are implemented in the calculation of position
and width of low energy resonances for radial barriers. The numerical
integrations are delimited by t/T<<8, with t the period of a classical particle
in the barrier trap and T the resonance lifetime. These energies are used in
the construction of `haired' short range potentials as the supersymmetric
partners of a given radial barrier. The new potentials could be useful in the
study of the transient phenomena which give rise to the Moshinsky's diffraction
in time.Comment: 12 pages, 4 figures, 3 table
State-of-the-art techniques for calculating spectral functions in models for correlated materials
The dynamical mean field theory (DMFT) has become a standard technique for
the study of strongly correlated models and materials overcoming some of the
limitations of density functional approaches based on local approximations. An
important step in this method involves the calculation of response functions of
a multiorbital impurity problem which is related to the original model.
Recently there has been considerable progress in the development of techniques
based on the density matrix renormalization group (DMRG) and related matrix
product states (MPS) implying a substantial improvement to previous methods. In
this article we review some of the standard algorithms and compare them to the
newly developed techniques, showing examples for the particular case of the
half-filled two-band Hubbard model.Comment: 8 pages, 4 figures, to be published in EPL Perspective
Reconstruction of the rotation center of the hip after oblong cups in revision total hip arthroplasty
Background The preoperative bone defect and the
reconstruction of the center of rotation of the hip are critical
in acetabular revision surgery. Uncemented oblong
cups are employed in order to manage these issues. We
analyzed the clinical results and rates of revision of two
different uncemented oblong cups, the reconstruction of the
center of rotation of the hip, as well as the rate of radiological
loosening and possible risk factors.
Materials and methods Forty-five patients (46 hips)
underwent acetabular revision surgery using two different
uncemented oblong cups.Weassessed the clinical results and
the survival rate for revision and aseptic loosening. Intraoperative
bone loss was classified according to Paprosky, and
acetabular reconstruction was assessed according to Ranawat.
The mean follow-up was 7.2 years (range 4–11 years).
Results There were four re-revisions (three due to aseptic
loosening); the survival rate for re-revision due to aseptic
loosening was 60.1 % at seven years. The mean distance
between the center of the femoral head prosthesis and the
approximate center of the femoral head improved from
21.5 to 10.2 mm. Thirteen cups showed radiological loosening;
the survival rate for radiological loosening at
seven years was 40.54 %. A smaller postoperative horizontal
distance was correlated with cup loosening.
Conclusions Although optimal acetabular reconstruction
can be achieved by using oblong uncemented cups in
revision hip surgery, the clinical and radiological results
are not encouraging. Excessive medialization of the cup
may increase the rate of loosenin
Doping and temperature dependence of Mn 3d states in A-site ordered manganites
We present a systematic study of the electronic structure in A-site ordered
manganites as function of doping and temperature. The energy dependencies
observed with soft x-ray resonant diffraction (SXRD) at the Mn L_{2,3} edges
are compared with structural investigations using neutron powder diffraction as
well as with cluster calculations. The crystal structures obtained with neutron
powder diffraction reflect the various orbital and charge ordered phases and
show an increase of the Mn-O-Mn bond angle as function of doping and
temperature. Cluster calculations show that the observed spectral changes in
SXRD as a function of doping are more pronounced than expected from an increase
in bandwitdh due to the increase in Mn-O-Mn bond angle, and are best described
by holes that are distributed at the neighbouring oxygen ions. These holes are
not directly added to the Mn 3d shell, but centered at the Mn site. In
contrast, the spectral changes in SXRD as function of temperature are best
described by an increase of magnetic correlations. This demonstrates the strong
correlations between orbitals and magnetic moments of the 3d states
Estudio de la iluminación natural en la edificación
En la estación de radiación solar e iluminación de alta calidad del International Daylight Measurement Program (IDMP) en Madrid ubicada en la terraza norte de la E.T.S. de Arquitectura de la Universidad Politécnica de Madrid (40º 25’ N, 3º 41’ W) se está realizando un estudio conjunto entre profesores de la ETSAM y de la EUATM sobre la iluminación natural en la Edificación. Desde hace más de un año, se están midiendo iluminancias globales en superficies horizontales, en superficies verticales con las cuatro orientaciones (N, S, E y O) y en superficies inclinadas con distintos ángulos de inclinación mediante un domo semiesférico sobre el que se colocan los sensores fotométricos. Todas estas medidas para los tres tipos de cielo (despejado, parcialmente cubierto y cubierto). También se ha construido un modelo a escala de un local de la ETSAM con la finalidad de medir la iluminación natural simultáneamente en el local y en el modelo reducido. Una vez conocida la viabilidad del modelo se ha estudiado la iluminación natural que tendrÃa dicho local, orientado al norte en la realidad, si estuviese orientado hacia el Sur, el Este o el Oeste. Con todo esto se han realizado varios trabajos de fin de máster del Máster en Técnicas y Sistemas de Edificación de la EUATM y se continúan realizando otros
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