Structural instability of vortices in Bose-Einstein condensates

In this paper we study a gaseous Bose-Einstein condensate (BEC) and show that: (i) A minimum value of the interaction is needed for the existence of stable persistent currents. (ii) Vorticity is not a fundamental invariant of the system, as there exists a conservative mechanism which can destroy a vortex and change its sign. (iii) This mechanism is suppressed by strong interactions.Comment: 4 pages with 3 figures. Submitted to Phys. Rev. Let

Collective unambiguous positioning with high-order BOC signals

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The unambiguous estimation of high-order BOC signals in harsh propagation conditions is still an open problem in the literature. This paper proposes to overcome the limitations observed in state-of-the-art unambiguous estimation techniques based on the application of existing direct positioning techniques and the exploitation of the spatial diversity introduced by arrays of antennas. In particular, the ambiguity problem is solved as a multiple-input multiple-output (MIMO) estimation problem in the position domain.Peer ReviewedPostprint (author's final draft

The palaeoweatherings on the iberian hercynian basernent: approach to a regional interpretation from sorne spanish profiles

The Hercynian basement of the Iberian Peninsula has undergone different stages of supergenic weathering which has given rise to a superposition of several «weathering mantles». Remnants ofan old weathering mantle, Mesozoic in age, and related to a planation surface older than the Alpine tectonic phases, have been found. Nowadays the fragments of this old surface appear unleveled and/or fossilized by younger sediments. likewise, related to the «Raña» sediments ofUpper Neogene-lower Pleistocene age, appears a weathering mantle, probably active today, which is rich in kaolinite and with strong hydromorphic features

Benchmarking CPUs and GPUs on embedded platforms for software receiver usage

Smartphones containing multi-core central processing units (CPUs) and powerful many-core graphics processing units (GPUs) bring supercomputing technology into your pocket (or into our embedded devices). This can be exploited to produce power-efficient, customized receivers with flexible correlation schemes and more advanced positioning techniques. For example, promising techniques such as the Direct Position Estimation paradigm or usage of tracking solutions based on particle filtering, seem to be very appealing in challenging environments but are likewise computationally quite demanding. This article sheds some light onto recent embedded processor developments, benchmarks Fast Fourier Transform (FFT) and correlation algorithms on representative embedded platforms and relates the results to the use in GNSS software radios. The use of embedded CPUs for signal tracking seems to be straight forward, but more research is required to fully achieve the nominal peak performance of an embedded GPU for FFT computation. Also the electrical power consumption is measured in certain load levels.Peer ReviewedPostprint (published version

Deterioro de monumentos graníticos por cristalización de sales en ambiente urbano con baja contaminación

The effect of salt crystallization on granite (s.l) rocks used as building material in an urban environment with low atmospheric pollution was studied. The manners of salt crystallization and the subsequent deterioration caused were analyzed in unweathered granite and other fades which had undergone strong transformations in quarries before being used as stone materials, "alterites".Se estudia el efecto de la cristalización de sales solubles en rocas graníticas s.l empleadas como materiales de construcción, en ambiente urbano con baja contaminación atmosférica. Las formas en que cristalizan las sales y el deterioro asociado a su presencia son analizados en granitos sanos y en otras facies que han sufrido fuertes transformaciones en cantera previas a su empleo como materiales de construcción ("alteritas")

Numerical modelling of oocytes partially covered by magnetic nanoparticles in external magnetic fields

Nanorep® is a novel device based on the magnetic tweezer concept that has been developed for precise, fast, and non-aggressive oocytes and embryos manipulation. To operate the reproductive cells, they are first immersed in a standard host medium with ferrite containing nanoparticles. The magnetic particles are attached to the external matrix of the oocytes/embryos thanks to a linked protein making possible to control them by using external magnetic fields. Electron microscope photographs show magnetic particle aggregates around the oocyte. The total mass and distribution of the attached magnetic particles per oocyte show a wide range of variability, which strongly affects their magnetic response. Despite the uncertainties on the attachment of magnetic nanoparticles, the set formed by the oocyte and the nanoparticles can be caught and transported by using standard neodymium magnets. Here we present an initial study of the interaction between the set oocyte/nanoparticles and the external magnetic field in aqueous environment. We are going to discuss several relevant topics of the model such us the characterization of magnetic field produced by cylindrical neodymium magnets, the model of the ferrite magnetization as an effective spherical dipole or a magnetized spherical shell, the measurement processes to obtain the temporal evolution of the particle position and the different observed dynamic behaviours

Anderson localization in a periodic photonic lattice with a disordered boundary

We investigate experimentally the light evolution inside a two-dimensional finite periodic array of weakly- coupled optical waveguides with a disordered boundary. For a completely localized initial condition away from the surface, we find that the disordered boundary induces an asymptotic localization in the bulk, centered around the initial position of the input beam.Comment: 3 pages, 4 figure

Enclavijado de Ender en las fracturas del macizo trocantéreo: análisis retrospectivo de la ocupación del canal medular

Se revisaron las historias clínicas de 226 pacientes afectos de fracturas del macizo trocantérico, tratadas mediante enclavijado de Ender en un periodo de 9 años en el Hospital del Insalud de Barbastro. La estabilidad de las fracturas se determinó mediante la clasificación de Ramadier. Se valoró el porcentaje de ocupación de la cavidad medular femoral por los clavos de Ender y la posible relación de este parámetro con la migración del material de osteosíntesis. Se evaluó también la utilidad del bloqueo distal de los clavos de Ender con agujas de Kirschner, en la prevención de su migración distal. Se comprobó una relación significativa entre el porcentaje de ocupación del canal medular y la migración distal del material en las fracturas inestables. El bloqueo distal con aguja de Kirschner no se acompañó de una menor incidencia en la migración distal de los clavos.A retrospective study was done on 226 trochanteric fractures managed with Ender nails during a 9 years period at the Insalud Hospital of Barbastro. Stability of these fractures was classified following Ramadier's criteria. Filling of the medular cavity by Ender nails and its relation with osteosyntehsis migration was analysed. Distal locking of Ender nails by Kirschner pins was evaluated to prevent its distal mobilization. A significative relationship was observed between a high filling rate of the medular cavity and lower distal migration rate in unestable trochanteric fractures. Distal locking of Ender nails was not accompanied of lower rate of distal osteosynthesis migratio

Caracterización productiva de las estirpes de cerdo ibérico reconocidas dentro del libro genealógico de la raza y del catálogo oficial de razas de ganado de España

Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (España