376 research outputs found

    Complete magnetic control over the superconducting thermoelectric effect

    Full text link
    Giant thermoelectric effects are known to arise at the interface between superconductors and strongly polarized ferromagnets, enabling the construction of efficient thermoelectric generators. We predict that the thermopower of such a generator can be completely controlled by a magnetic input signal: Not only can the thermopower be toggled on and off by rotating a magnet, but it can even be entirely reversed. This in situ control diverges from conventional thermoelectrics, where the thermopower is usually fixed by the device desig

    Tratamiento de las fracturas supracondíleas de húmero con desplazamiento en niños

    Get PDF
    Se realiza un estudio retrospectivo de 188 niños con fracturas supracondíleas de húmero desplazadas tratados en nuestro Servicio durante los años 1986 a 1997 mediante reducción cerrada y enclavijamiento de la fractura con dos agujas de kirschner. Se utilizó la clasificación de Gartland para la valoración del desplazamiento de la fractura y se estudiaron los resultados tanto desde el punto de vista radiológico como clínico siguiendo los criterios de Flynn. Estos resultados fueron considerados como satisfactorios en 154 casos (82%) en el seguimiento a largo plazo. Se constató la ausencia del pulso radial en 22 casos (12%) recuperándose en todos ellos después de la reducción y estabilización de la fractura y 28 casos (15%) de lesiones neurológicas que se recuperaron en un plazo comprendido entre dos y seis meses. La secuela más frecuente fue el cúbito varo en 23 casos (12%) con escasa repercusión funcional.A retrospective study of 188 children complaining of displaced supracondylar fractures of the humerus was performed. The period of the study was 1986 to 1997 and all the fractures were treated by closed reduction and percutaneous pinning with two kirschner wires. Gartland classification was used to assess the fracture's displacement. The results were studied clinically and radiologically following Flynn criteria. In the long term follow up 154 cases (82%) were considered satisfactory. A lack of radial pulse was reported in 22 cases (12%) and in all of them a total recovery was achieved after the reduction and stabilization of the fracture. We also record 28 cases (15%) of neural injuries with full recovery between two and six months time. The most frequent permanent damage was cubitus varus in 23 cases (12%) but with little functional impairment

    Model independent bounds on the tau lepton electromagnetic and weak magnetic moments

    Get PDF
    Using LEP1, SLD and LEP2 data, for tau lepton production, and data from CDF, D0 and LEP2, for W decays into tau leptons, we set model independent limits on non-standard electromagnetic and weak magnetic moments of the tau lepton. The most general effective Lagrangian giving rise to tau moments is used without further assumptions. Precise bounds (2σ2\sigma) on the non-standard model contributions to tau electromagnetic (0.007<aγ<0.005-0.007<a_\gamma< 0.005), tau Z-magnetic (0.0024<aZ<0.0025-0.0024 <a_Z< 0.0025) and tau W-magnetic (0.003<κW<0.004-0.003 < \kappa^W < 0.004) dipole moments are set from the analysis.Comment: 19 pages, 2 figures, elsart.sty. Revised version with new data. Accepted for publication in Nucl. Phys.

    Observation of magnetic state dependent thermoelectricity in superconducting spin valves

    Full text link
    Superconductor-ferromagnet tunnel junctions demonstrate giant thermoelectric effects which are being exploited to engineer ultra-sensitive terahertz radiation detectors. Here, we experimentally observe the recently predicted complete magnetic control over thermoelectric effects in a superconducting spin valve, including the dependence of its sign on the magnetic state of the spin valve. The description of the experimental results is improved by the introduction of an interfacial domain wall in the spin filter layer interfacing the superconductor. Surprisingly, the application of high in-plane magnetic fields induces a double sign inversion of the thermoelectric effect, which exhibits large values even at applied fields twice the superconducting critical field

    Web per a un club esportiu

    Get PDF
    Aquest Projecte Final de Carrera va sorgir per la necessitat que tenia el Club Esportiu Escola Sant Gervasi per poder tenir un control de la seva gestió esportiva mitjançant una aplicació web i poder també emmagatzemar les valoracions que es fan sobre els esportistes del Club. L'aplicació inclou altres funcionalitats com les de poder consultar horaris d'entrenament, calendaris o classificacions. Fent servir tecnologies tals com PHP, HTML, JavaScript i AJAX, s'ha implementat aquesta aplicació que serà de gran utilitat per als coordinadors, entrenadors i jugadors que formen part del Club.Este Proyecto Final de Carrera surgió por la necesidad que tenía el Club Esportiu Escola Sant Gervasi de poder tener un control de su gestión deportiva a través de una aplicación web y poder también almacenar las valoraciones que se hacen sobre los deportistas del Club. La aplicación incluye otras funcionalidades como las de poder consultar horarios de entrenamiento, calendarios o clasificaciones. Haciendo servir tecnologías como PHP, HTML, JavaScript y Ajax, se ha implementado esta aplicación que será de gran utilidad para los coordinadores, entrenadores y jugadores que forman parte del Club.This End Of Career Project raised because of the needed that the Club Esportiu Escola Sant Gervasi had for taking control of it's sports management using a web application and also for storing the Club's players valorations. The application includes other functionalities such as consult timetables, calendars or standings. Using technologies such as PHP, HTML, JavaScript and AJAX, the application has been implemented. This application will have a great utility for coordinators, trainers and players that are part of the Club

    Superconductivity-induced change in magnetic anisotropy in epitaxial ferromagnet-superconductor hybrids with spin-orbit interaction

    Get PDF
    The interaction between superconductivity and ferromagnetism in thin film superconductor/ferromagnet heterostructures is usually reflected by a change in superconductivity of the S layer set by the magnetic state of the F layers. Here we report the converse effect: transformation of the magnetocrystalline anisotropy of a single Fe(001) layer, and thus its preferred magnetization orientation, driven by the superconductivity of an underlying V layer through a spin-orbit coupled MgO interface. We attribute this to an additional contribution to the free energy of the ferromagnet arising from the controlled generation of triplet Cooper pairs, which depends on the relative angle between the exchange field of the ferromagnet and the spin-orbit field. This is fundamentally different from the commonly observed magnetic domain modification by Meissner screening or domain wall-vortex interaction and offers the ability to fundamentally tune magnetic anisotropies using superconductivity - a key step in designing future cryogenic magnetic memories.Comment: Submitted for publicatio

    Superconductivity assisted change of the perpendicular magnetic anisotropy in V/MgO/Fe junctions

    Full text link
    Controlling the perpendicular magnetic anisotropy (PMA) in thin films has received considerable attention in recent years due to its technological importance. PMA based devices usually involve heavy-metal (oxide)/ferromagnetic-metal bilayers, where, thanks to interfacial spin-orbit coupling (SOC), the in-plane (IP) stability of the magnetization is broken. Here we show that in V/MgO/Fe(001) epitaxial junctions with competing in-plane and out-of-plane (OOP) magnetic anisotropies, the SOC mediated interaction between a ferromagnet (FM) and a superconductor (SC) enhances the effective PMA below the superconducting transition. This produces a partial magnetization reorientation without any applied field for all but the largest junctions, where the IP anisotropy is more robust; for the smallest junctions there is a reduction of the field required to induce a complete OOP transition (HOOPH_\text{OOP}) due to the stronger competition between the IP and OOP anisotropies. Our results suggest that the degree of effective PMA could be controlled by the junction lateral size in the presence of superconductivity and an applied electric field. We also discuss how the HOOPH_\text{OOP} field could be affected by the interaction between magnetic stray fields and superconducting vortices. Our experimental findings, supported by numerical modelling of the ferromagnet-superconductor interaction, open pathways to active control of magnetic anisotropy in the emerging dissipation-free superconducting spin electronics.Comment: Submitte

    Enhancing Writing Self-Efficacy Beliefs of Students with Learning Disabilities Improves their Writing Processes and Products

    Get PDF
    p. 195-206.La autoeficacia se muestra como uno de los determinantes motivacionales más importantes por lo que parece tener gran influencia sobre el rendimiento académico de los alumnos. Por ello, el presente estudio examina la influencia de la auto-eficacia en los procesos y productos de composición escrita, a través de una intervención específica que entrena las cuatro fuentes de autoeficacia propuestas por Bandura. Método.Un total de 60 alumnos con dificultades de aprendizaje o bajo rendimiento de 5º y 6º de Educación Primaria, se han distribuido en dos grupos: uno experimental(40 alumnos), que ha sido sometido a 10 sesiones de instrucción específica en autoeficacia hacia la escritura, dentro de su contexto escolar; y otro grupo control (20 alumnos) que han recibido el currículum ordinario. Resultados.Los datos muestranuna mejora significativa no sólo de los textos escritos por los alumnos con DA sino también de los procesos que llevan a cabo a la hora de escribir, pero sólo en los alumnos intervenidos Discusión y Conclusión.Se requieren más estudios instruccionales y experimentales para confirmar la naturaleza de la relación proceso-producto en composición escrita, pero parece que están asegurados los beneficios de utilizar un modelo de proceso-producto de la escrituraS
    corecore