Absence of charge backscattering in the nonequilibrium current of normal-superconductor structures

We study the nonequilibrium transport properties of a normal-superconductor-normal structure, focussing on the effect of adding an impurity in the superconducting region. Current conservation requires the superfluid velocity to be nonzero, causing a distortion of the quasiparticle dispersion relation within the superconductor. For weakly reflecting interfaces we find a regime of intermediate voltages in which Andreev transmission is the only permitted mechanism for quasiparticles to enter the superconductor. Impurities in the superconductor can only cause Andreev reflection of these quasiparticles and thus cannot degrade the current. At higher voltages, a state of gapless superconductivity develops which is sensitive to the presence of impurities.Comment: Latex file, 11 pages, 2 figures available upon request [email protected], to be published in Journal of Physics: Condensed Matte

Electrochemical synthesis of peroxomonophosphate using boron-doped diamond anodes

A new method for the synthesis of peroxomonophosphate, based on the use of boron-doped diamond electrodes, is described. The amount of oxidant electrogenerated depends on the characteristics of the supporting media (pH and solute concentration) and on the operating conditions (temperature and current density). Results show that the pH, between values of 1 and 5, does not influence either the electrosynthesis of peroxomonophosphate or the chemical stability of the oxidant generated. Conversely, low temperatures are required during the electrosynthesis process to minimize the thermal decomposition of peroxomonophosphate and to guarantee significant oxidant concentration. In addition, a marked influence of both the current density and the initial substrate is observed. This observation can be explained in terms of the contribution of hydroxyl radicals in the oxidation mechanisms that occur on diamond surfaces. In the assays carried out below the water oxidation potential, the generation of hydroxyl radicals did not take place. In these cases, peroxomonophosphate generation occurs through a direct electron transfer and, therefore, at these low current densities lower concentrations are obtained. On the other hand, at higher potentials both direct and hydroxyl radical-mediated mechanisms contribute to the oxidant generation and the process is more efficient. In the same way, the contribution of hydroxyl radicals may also help to explain the significant influence of the substrate concentration. Thus, the coexistence of both phosphate and hydroxyl radicals is required to ensure the generation of significant amounts of peroxomonophosphoric acid

Self-consistent scattering description of transport in normal-superconductor structures

We present a scattering description of transport in several normal-superconductor structures. We show that the related requirements of self-consistency and current conservation introduce qualitative changes in the transport behavior when the current in the superconductor is not negligible. The energy thresholds for quasiparticle propagation in the superconductor are sensitive to the existence of condensate flow ($v_s\neq 0$). This dependence is responsible for a rich variety of transport regimes, including a voltage range in which only Andreev transmission is possible at the interfaces, and a state of gapless superconductivity which may survive up to high voltages if temperature is low. The two main effects of current conservation are a shift towards lower voltages of the first peak in the differential conductance and an enhancement of current caused by the greater availability of charge transmitting scattering channels.Comment: 31 pages, 10 PS figures, Latex file, psfig.sty file is added. To appear in Phys. Rev. B (Jan 97

THE RELATIONSHIP BETWEEN LEVEL OF EDUCATION, ORGANIZATIONAL COMMITMENT AND JOB SATISFACTION: AN ANALYSIS IN HOTEL ESTABLISHMENTS IN ANDALUSIA (SPAIN)

Nisu svi zaposlenici sposobni generirati vještine i resurse kojima bi se ostvarila organizacijska produktivnost. Samo su kvalificirani ljudski resursi (HR), prepo¬znati i odani politici tvrtke, dio organizacijskih kompetencija. Stoga su čimbenici zadovoljstva zapo¬slenika radom te predanost tvrtki dvije ključne varijable koje moramo analizirati kako bismo ispravno procijenili i pravilno upravljali ljudskim kapitalom tvrtke. Posebno se velika važnost pridaje vrijed¬nosti obrazovanja zaposlenika u svjetlu konkurentnosti turizma, što je u skladu s pretpostavkom kako stupanj obrazovanja zaposlenika izravno utječe na kvalitetu turističkih usluga. Cilj je ovog članka analizirati zadovoljstvo radnim mjestom i organizacijske obveze zaposlenika hotelskih kuća u Andaluziji (Španjolska), destinaciji čija je nesumnjiva konkurentska važnost u turi¬zmu neupitna. Pronađene su evidentne razlike u stupnju obrazovanja zaposlenika, tako da rezultati svakako ohrabruju odjele upravljanja ljudskim resursima na identifikaciju, održavanje i razvoj resursa i potencijalnih sposobnosti njihovog ljudskog kapitala.Not all employees are capable of generating skills and resources that may result in organizational productivity. Only qualified Human Resources, identified and committed to the company policy, are a part of the organization\u27s competences. Therefore, elements like the worker\u27s job satisfaction or the organizational commitment are two fundamental variables that need to be analyzed for the measurement and correct management of the company\u27s human capital. Further¬more, the importance that the value of the workers\u27 education presents towards competitiveness in tourism is highlighted since it is assumed that staff education is directly related to the quality of tourist service. The purpose of this paper is to analyze the relationship among educational level, job satisfaction, and organizational commitment of the employees of the hotel establishments in Andalusia (Spain), a destination of undeniable competitive significance in tourism. Evident differences were found among the level of education of workers, so the results have to encourage the human resources management to identify, maintain, and develop the resources and potential capabilities of their human capital

An Efficient Pseudospectral Method for the Computation of the Self-force on a Charged Particle: Circular Geodesics around a Schwarzschild Black Hole

The description of the inspiral of a stellar-mass compact object into a massive black hole sitting at a galactic centre is a problem of major relevance for the future space-based gravitational-wave observatory LISA (Laser Interferometer Space Antenna), as the signals from these systems will be buried in the data stream and accurate gravitational-wave templates will be needed to extract them. The main difficulty in describing these systems lies in the estimation of the gravitational effects of the stellar-mass compact object on his own trajectory around the massive black hole, which can be modeled as the action of a local force, the self-force. In this paper, we present a new time-domain numerical method for the computation of the self-force in a simplified model consisting of a charged scalar particle orbiting a nonrotating black hole. We use a multi-domain framework in such a way that the particle is located at the interface between two domains so that the presence of the particle and its physical effects appear only through appropriate boundary conditions. In this way we eliminate completely the presence of a small length scale associated with the need of resolving the particle. This technique also avoids the problems associated with the impact of a low differentiability of the solution in the accuracy of the numerical computations. The spatial discretization of the field equations is done by using the pseudospectral collocation method and the time evolution, based on the method of lines, uses a Runge-Kutta solver. We show how this special framework can provide very efficient and accurate computations in the time domain, which makes the technique amenable for the intensive computations required in the astrophysically-relevant scenarios for LISA.Comment: 15 pages, 9 figures, Revtex 4. Minor changes to match published versio

Una experiencia piloto de aplicación del inglés en los estudios de Turismo y Empresariales de la Universidad de Córdoba

El coneixement de la llengua anglesa és bàsica en qualsevol titulació universitària, amb molta importància en els estudis de Turisme i Empresarials. Durant els cursos 2007-08 i 2008-2009 s’ha realitzat una experiència pilot en diferents assignatures d’ambdues titulacions amb l’objectiu de que els estudiants comprenguin la importància de l’anglès com element bàsic en la seva carrera professional. Per aquest motiu, i utilitzant la plataforma Moodle, s’ha construït una experiència on l’alumnat ha desenvolupat diferents activitats emmarcades en diferents nivells d’aprenentatge de l’ idioma. L’objectiu és que paulatinament s’arribés a conèixer, assimilar i definir en anglès els conceptes més importants relacionats amb els continguts acadèmics vistos en les assignatures.The knowledge of the English language is essential in any university degree, especially in Tourism and Business Studies. During courses 2007-08 and 2008-2009 we have carried out a pilot experience in several subjects of both degrees in order that students understand the importance of English as a basic element in their professional future. We have used the platform Moodle to design an experience where the student has developed different activities classified in several learning levels. The objective is that step by step they acquire, assimilate and define in English the most important concepts related to the academic contents of their subjects.El conocimiento del idioma inglés es básico en cualquier titulación universitaria, con más importancia si cabe en los estudios en Turismo y Empresariales. Durante los cursos 2007-08 y 2008-2009 se ha realizado una experiencia piloto en diversas asignaturas de ambas titulaciones con el objetivo de que los estudiantes comprendan la importancia del inglés como elemento básico en su carrera profesional. Para ello, y utilizando la plataforma Moodle, se ha vertebrado una experiencia donde el alumnado ha desarrollado distintas actividades enmarcadas en varios niveles de aprendizaje del idioma. El objetivo es que paulatinamente se llegara a conocer, asimilar y definir en inglés los conceptos más importantes relacionados con los contenidos académicos vistos en las asignaturas

Motor Dysfunction as a Prodrome of Parkinson's Disease

BACKGROUND: Recognition of motor signs in the prodromal stage could lead to best identify populations at risk for developing Parkinson's disease (PD). OBJECTIVE: This study identified motor symptoms and signs in individuals suspected of having PD but who did not have a progressive reduction in the speed and amplitude of finger tapping or other physical signs indicative of bradykinesia. METHODS: 146 patients, who had symptoms or signs suggestive of PD, were serially evaluated by a movement disorder specialist, using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III and video recordings. If the patients 'converted' to PD during follow-up, they were categorized as cases and compared with those who did not meet PD criteria during follow-up (non-cases). RESULTS: The 82 cases were more likely to have action dystonia or postural/action/rest tremor of a limb (OR 2.8; 95% CI 1.10-7.09; p = 0.02), a reduced blink rate at rest (OR 2.32; 95% CI 1.18-4.55; p = 0.01), anxiety (OR 8.91; 95% CI 2.55-31.1; p <  0.001), depression (OR 7.03; 95% CI 2.86-17.2; p <  0.001), or a frozen shoulder (OR 3.14; 95% CI 1.58-6.21) than the 64 'non-cases'. A reduction of the fast blink rate was common in patients who met the criteria for PD (p <  0.001). CONCLUSIONS: This study emphasizes that motor dysfunction is a component of the clinical prodrome seen in some patients with PD

Buenas prácticas de innovación docente en la Universidad de Córdoba

Acercar el mundo empresarial de la provincia a la Universidad de Córdoba es el principal reto de esta iniciativa. Para ello, los docentes del área de Organización de Empresas han elaborado cuatro casos de empresas – Covap, Faasa Aviación, Esparta Desing y Cruzber- que por su cercanía despiertan la curiosidad del alumnado y ofrecen la posibilidad de conocer sus instalaciones. La difusión de los casos –la elaboración de cada uno de ellos tiene un coste de unos 2.000 euros– se ha realizado en formato papel, a través libros y revistas, y también vía Internet

A comparison of electrochemical degradation of phenol on boron doped diamond and lead dioxide anodes

This work compares two electrode materials used to mineralize phenol contained in waste waters. Two disks covered with either boron doped diamond (BDD) or PbO2 were used as anodes in a one compartment flow cell under the same hydrodynamic conditions. Efficiencies of galvanostatic electrolyses are compared on the basis of measurements of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD). Galvanostatic electrolyses were monitored by analysis of phenol and of its oxidation derivatives to evaluate the operating time needed for complete elimination of toxic aromatics. The experimental current efficiency is close to the theoretical value for the BDD electrode. Other parameters being equal, phenol species disappeared at the same rate using the two electrode materials but the BDD anode showed better efficiency to eliminate TOC and COD. Moreover, during the electrolysis less intermediates are formed with BDD compared to PbO2 whatever the current density. A comparison of energy consumption is given based on the criterion of 99% removal of aromatic compounds

Signatures of non-locality in the first-order coherence of the scattered light

The spatial coherence of an atomic wavepacket can be detected in the scattered photons, even when the center-of-mass motion is in the quantum coherent superposition of two distant, non-overlapping wave packets. Spatial coherence manifests itself in the power spectrum of the emitted photons, whose spectral components can exhibit interference fringes as a function of the emission angle. The contrast and the phase of this interference pattern provide information about the quantum state of the center of mass of the scattering atom.Comment: 5 pages, one figure, submitted to Laser Physics, special issue in memory of Herbert Walthe