Construction of exact solutions by spatial traslations in inhomogeneous Nonlinear Schrodinger equations. Applications to Bose-Einstein condensation

In this paper we study a general nonlinear Schr\"odinger equation with a time dependent harmonic potential. Despite the lack of traslational invariance we find a symmetry trasformation which, up from any solution, produces infinitely many others which are centered on classical trajectories. The results presented here imply that, not only the center of mass of the wave-packet satisfies the Ehrenfest theorem and is decoupled from the dynamics of the wave-packet, but also the shape of the solution is independent of the behaviour of the center of the wave. Our findings have implications on the dynamics of Bose-Einstein condensates in magnetic trapsComment: Submitted to Phys. Re

Split vortices in optically coupled Bose-Einstein condensates

We study a rotating two-component Bose-Einstein condensate in which an optically induced Josephson coupling allows for population transfer between the two species. In a regime where separation of species is favored, the ground state of the rotating system displays domain walls with velocity fields normal to them. Such a configuration looks like a vortex split into two halves, with atoms circulating around the vortex and changing their internal state in a continuous way.Comment: 4 EPS pictures, 4 pages; Some errata have been corrected and thep resentation has been slightly revise

Anomalous rotational properties of Bose-Einstein condensates in asymmetric traps

We study the rotational properties of a Bose-Einstein condensate confined in a rotating harmonic trap for different trap anisotropies. Using simple arguments, we derive expressions for the velocity field of the quantum fluid for condensates with or without vortices. While the condensed gas describes open spiraling trajectories, on the frame of reference of the rotating trap the motion of the fluid is against the trap rotation. We also find explicit formulae for the angular momentum and a linear and Thomas-Fermi solutions for the state without vortices. In these two limits we also find an analytic relation between the shape of the cloud and the rotation speed. The predictions are supported by numerical simulations of the mean field Gross-Pitaevskii model.Comment: 4 RevTeX pages, 2 EPS figures; typos fixed, reference adde

First recorded case of leucism in the velvet belly lantern shark Etmopterus spinax (Squaliformes: Etmopteridae)

Poster presentado en el SIBIC 2022 IX Iberian Congress of IchthyologyThe capture of a female specimen of the velvet belly lantern shark Etmopterus spinax with abnormal skin coloration is reported. The specimen was captured off northern Spain (Bay of Biscay, North-Eastern Atlantic) in 2021 by bottom trawling. The lack of dermal melanophores combined with a normal retinal pigmentation, lead us to considérate the specimen as leucistic. This is the first case of leucism in E. spinax and the second record of colour aberration in the family Etmopteridae

Scattering of dipole-mode vector solitons: Theory and experiment

We study, both theoretically and experimentally, the scattering properties of optical dipole-mode vector solitons - radially asymmetric composite self-trapped optical beams. First, we analyze the soliton collisions in an isotropic two-component model with a saturable nonlinearity and demonstrate that in many cases the scattering dynamics of the dipole-mode solitons allows us to classify them as ``molecules of light'' - extremely robust spatially localized objects which survive a wide range of interactions and display many properties of composite states with a rotational degree of freedom. Next, we study the composite solitons in an anisotropic nonlinear model that describes photorefractive nonlinearities, and also present a number of experimental verifications of our analysis.Comment: 8 pages + 4 pages of figure

Variación temporal de las concentraciones de PCBs en tejido de mejillón de dos zonas de la Bahía de Santander (España)

Se presenta la variación temporal de bifenilos policlorados (PCBs) en mejillón silvestre Mytilus galloprovincialis de dos zonas de la Bahía de Santander (norte de España) de 1991 a 2003, así como la posible influencia en sus concentraciones de los diferentes aportes externos a que están sometidas ambas zonas. Las concentraciones de SCB7 (suma de los CBs Nos. IUPAC: 28, 52, 101, 118, 138, 153 y 180) de la zona de Pantalán, oscilan entre los 21 μg kg–1 en peso húmedo (ph) y los 38 μg kg–1 ph Mientras que en la zona de Pedreña, con menor influencia antropogénica, varían entre un mínimo de 8 μg kg–1 ph y un máximo de 15 μg kg–1 ph Para conocer la evolución temporal, se usa el coeficiente de correlación Tau-b de Kendall y se comprueba la existencia de una tendencia decreciente significativa en los niveles de PCBs en ambas zonas.An analysis was made of the temporal variation of polychlorinated biphenyls (PCBs) in wild mussel, Mytilus galloprovincialis, from two areas of Santander Bay (northern Spain) during 1991–2003, as well as of the posible influence of different external contributions on their concentrations. The concentrations of the sum of seven PCBs (IUPAC numbers 28, 52, 101, 118, 138, 153 and 180) from the Pantalán area ranged from 21 to 38 μg kg–1 wet weight, whereas those from the Pedreña area, subject to less anthropogenic influence, ranged from 8 to 15 μg kg–1 wet weight. To determine the temporal evolution, the Kendall Tau-b correlation coefficient was used and a decreasing trend in PCB levels was verified for both areas.Publicado

Globally-Linked Vortex Clusters in Trapped Wave Fields

We put forward the existence of a rich variety of fully stationary vortex structures, termed H-clusters, made of an increasing number of vortices nested in paraxial wave fields confined by trapping potentials. However, we show that the constituent vortices are globally linked, rather than products of independent vortices. Also, they always feature a monopolar global wave front and exist in nonlinear systems, such as Bose-Einstein condensates. Clusters with multipolar global wave fronts are non-stationary or at best flipping.Comment: 4 pages, 5 PostScript figure

Prevalence of electrocardiographic findings associated to sudden cardiac death: spontaneous type 1 and type 2 Brugada patterns and QT disorders in spanish population older than forty years

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Electromyography: a simple and accessible tool to assess physical performance and health during hypoxia training. A systematic review

Hypoxia causes reduced partial pressure of oxygen in arterial blood and induces adaptations in skeletal muscle that may affect individuals’ physical performance and muscular health. These muscular changes are detectable and quantifiable by electromyography (EMG), an instrument that assesses electrical activity during active contraction at rest. EMG is a relatively simple and accessible technique for all patients, one that can show the degree of the sensory and motor functions because it provides information about the status of the peripheral nerves and muscles. The main goal of this review is to evaluate the scientific evidence of EMG as an instrument for monitoring different responses of skeletal muscles subjected to external stimuli such as hypoxia and physical activity. A structured search was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in Medline/PubMed, Scielo, Google Scholar, Web of Science, and Cochrane Library Plus. The search included articles published in the last 25 years until May 2020 and was restricted to English- and Spanish-language publications. As such, investigators identified nine articles that met the search criteria. The results determined that EMG was able to detect muscle fatigue from changes in the frequency spectrum. When a muscle was fatigued, high frequency components decreased and low frequency components increased. In other studies, EMG determined muscle activation increased during exercise by recruiting motor units and by increasing the intensity of muscle contractions. Finally, it was also possible to calculate the mean quadriceps quadratic activity used to obtain an image of muscle activation. In conclusion, EMG offers a suitable tool for monitoring the different skeletal muscle responses and has sufficient sensitivity to detect hypoxia-induced muscle changes produced by hypoxic stimuli. Moreover, EMG enhances an extension of physical examination and tests motor-system integrity