Anisotropic thermal emission from magnetized neutron stars

The thermal emission from isolated neutron stars is not well understood. The X-ray spectrum is very close to a blackbody but there is a systematic optical excess flux with respect to the extrapolation to low energy of the best blackbody fit. This fact, in combination with the observed pulsations in the X-ray flux, can be explained by anisotropies in the surface temperature distribution.We study the thermal emission from neutron stars with strong magnetic fields in order to explain the origin of the anisotropy. We find (numerically) stationary solutions in axial symmetry of the heat transportequations in the neutron star crust and the condensed envelope. The anisotropy in the conductivity tensor is included consistently. The presence of magnetic fields of the expected strength leads to anisotropy in the surface temperature. Models with toroidal components similar to or larger than the poloidal field reproduce qualitatively the observed spectral properties and variability of isolated neutron stars. Our models also predict spectral features at energies between 0.2 and 0.6 keV.Comment: 18 pages, 19 figures, version accepted for publication in A&

Real time motion estimation using a neural architecture implemented on GPUs

This work describes a neural network based architecture that represents and estimates object motion in videos. This architecture addresses multiple computer vision tasks such as image segmentation, object representation or characterization, motion analysis and tracking. The use of a neural network architecture allows for the simultaneous estimation of global and local motion and the representation of deformable objects. This architecture also avoids the problem of finding corresponding features while tracking moving objects. Due to the parallel nature of neural networks, the architecture has been implemented on GPUs that allows the system to meet a set of requirements such as: time constraints management, robustness, high processing speed and re-configurability. Experiments are presented that demonstrate the validity of our architecture to solve problems of mobile agents tracking and motion analysis

A study of the effect of projectile orientation on the results of ballistic impact tests as described in the EASA CS-25 regulations for fuel tank access covers

This paper presents the results of an investigation of the ballistic limits and failure modes of AA2024-T351 sheets impacted with cubical projectiles. The experiment/test setup was based on EASA CS-25 regulations for fuel tank access covers. The effect of cube orientation on the ballistic limit and failure modes was considered in detail. A 25% variation in ballistic limit was observed with the lowest ballistic limit (202 m/s) observed for the cubical projectile edge impacted on the target. In the cube face impacts, the ballistic limit was higher (223 m/s), and the highest ballistic limit (254 m/s) was observed for the corner impact. The observed differences in the ballistic limit were due to differences in failure mechanism, which resulted in different localised deformations near the projectile impact point, but also led to differences in global dishing deformation

3D reconstruction of medical images from slices automatically landmarked with growing neural models

In this study, we utilise a novel approach to segment out the ventricular system in a series of high resolution T1-weighted MR images. We present a brain ventricles fast reconstruction method. The method is based on the processing of brain sections and establishing a fixed number of landmarks onto those sections to reconstruct the ventricles 3D surface. Automated landmark extraction is accomplished through the use of the self-organising network, the growing neural gas (GNG), which is able to topographically map the low dimensionality of the network to the high dimensionality of the contour manifold without requiring a priori knowledge of the input space structure. Moreover, our GNG landmark method is tolerant to noise and eliminates outliers. Our method accelerates the classical surface reconstruction and filtering processes. The proposed method offers higher accuracy compared to methods with similar efficiency as Voxel Grid

Diagnostic criteria for bipolarity based on an international sample of 5,635 patients with DSM-IV major depressive episodes

To assess the clinical validity of individual DSM-IV criteria for hypomania. In an international sample of 5,635 patients with major depressive episodes (Bridge Study), DSM-IV criteria for hypomania (stem questions, number and quality of symptoms, duration and exclusion criteria) were systematically assessed and their validity analysed on the basis of clinical data including family history, course, and other clinical characteristics. Three stem questions for hypomania, irritability, elevated mood and the added question of increased activity, showed comparable validity. The results support the current DSM-IV requirement for a higher symptom threshold (4 of 7 hypomanic symptoms) in cases of irritable mood. Longer durations of hypomanic episodes were associated with higher scores on all validators. The results did not support the DSM-IV durational requirements for hypomanic episodes (4days) and manic episodes (7days). Brief hypomanic episodes of 1, 2 or 3days were valid and would meet validity criteria for inclusion. The three exclusion criteria in DSM-IV (hypomania due to the use of antidepressants or of other substances, or to other medical conditions) were found to exclude patients with bipolar depression and should therefore not be retained. These results support several revisions of the DSM-IV concept of hypomanic episodes: specifically, the inclusion of increased activity as a gate question, the inclusion of 1 or 2 to 3-day episodes and the elimination of all exclusion criteri

Luxación recidivante de prótesis total de cadera

Más del 50% de los casos de caderas inestables se pueden resolver mediante la reducción cerrada de la luxación. Un intento sistemático para entender la causa de la inestabilidad, normalmente suele conducir a un tratamiento eficaz del problema cuando hace falta cirugía. Los componentes constreñidos o de retención han mejorado las posibilidades de resolver los problemas difíciles de inestabilidad, pero los efectos negativos potenciales de estos componentes deben tenerse también en cuenta. Los implantes tripolares, cuyos resultados clínicos en la literatura son muy alentadores, ocupan un lugar de elección en el arsenal terapéutico de la inestabilidad protética

Use of mixed methods designs in substance research: a methodological necessity in Nigeria

The utility of mixed methods (qualitative and quantitative) is becoming increasingly accepted in health sciences, but substance studies are yet to substantially benefit from such utilities. While there is a growing number of mixed methods alcohol articles concerning developed countries, developing nations are yet to embrace this method. In the Nigerian context, the importance of mixed methods research is yet to be acknowledged. This article therefore, draws on alcohol studies to argue that mixed methods designs will better equip scholars to understand, explore, describe and explain why alcohol consumption and its related problems are increasing in Nigeria. It argues that as motives for consuming alcohol in contemporary Nigeria are multiple, complex and evolving, mixed method approaches that provide multiple pathways for proffering solutions to problems should be embraced

Investigación en metodologías de aprendizaje para grupos ARA en la materia de arquitectura de computadores

La enseñanza en inglés es uno de los retos a los que se está enfrentando actualmente la universidad española. La Universidad de Alicante ofrece a través de los grupos de Alto Rendimiento Académico (ARA) parte de la docencia de los estudios de grado en inglés. El objetivo principal de esta red es la de consolidar y ampliar la investigación realizada en metodologías de aprendizaje para grupos ARA en la materia de arquitectura de computadores. En consecuencia, se pretende ampliar los materiales docentes en inglés en relación con la enseñanza de asignaturas relacionadas con la materia en estos grupos de alto rendimiento. Estas asignaturas son impartidas por varios miembros de la red en diferentes cursos de los Grados de Ingeniería Informática y de Ingeniería en Sonido e Imagen en Telecomunicación. Como caso práctico, se ha continuado con la investigación en la asignatura Arquitectura de Computadores del Grado de Ingeniería Informática. Para ello, se han elaborado nuevos materiales para prácticas que permiten la participación activa y el trabajo en equipo. Cada uno de los materiales propuestos está diseñado dentro del marco metodológico implementado en la asignatura, relacionado con la consecución de objetivos y competencias, y con la evaluación de la misma