15 research outputs found

    The role of temperature in the magnetic irreversibility of type-I Pb superconductors

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    Evidence of how temperature takes part in the magnetic irreversibility in the intermediate state of a cylinder and various disks of pure type-I superconducting lead is presented. Isothermal measurements of first magnetization curves and magnetic hysteresis cycles are analyzed in a reduced representation that defines an equilibrium state for flux penetration in all the samples and reveals that flux expulsion depends on temperature in the disks but not in the cylinder. The magnetic field at which irreversibility sets in along the descending branch of the hysteresis cycle and the remnant magnetization at zero field are found to decrease with temperature in the disks. The contributions to irreversibility of the geometrical barrier and the energy minima associated to stress defects that act as pinning centers on normal-superconductor interfaces are discussed. The differences observed among the disks are ascribed to the diverse nature of the stress defects in each sample. The pinning barriers are suggested to decrease with the magnetic field to account for these results

    Determinacions del perfil genètic de tumors sòlids de l’adult

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    Perfil genètic; Tumors sòlids; Adults; PrecisióPerfil genético; Tumores sólidos; Adultos; PrecisiónGenetic profile; Solid tumors; Adults; AccuracyEn aquest estudi s’ha definit la llista de gens per a cada patologia i tots ells han estat seleccionats atenent a; la seva utilitat diagnòstica per definir els subtipus tumorals en localitzacions tumorals molt concretes; la seva utilitat pronòstica i predictiva, sempre que això comporti un canvi d’actitud terapèutica; la seva utilitat terapèutica per a la indicació de l’ús de fàrmacs diana

    Determinacions del perfil genètic de tumors sòlids de l’adult

    Get PDF
    Perfil genètic; Tumors sòlids; Adults; PrecisióPerfil genético; Tumores sólidos; Adultos; PrecisiónGenetic profile; Solid tumors; Adults; AccuracyEn aquest estudi s’ha definit la llista de gens per a cada patologia i tots ells han estat seleccionats atenent a; la seva utilitat diagnòstica per definir els subtipus tumorals en localitzacions tumorals molt concretes; la seva utilitat pronòstica i predictiva, sempre que això comporti un canvi d’actitud terapèutica; la seva utilitat terapèutica per a la indicació de l’ús de fàrmacs diana

    A Qualitative Exploration of the Use of Contraband Cell Phones in Secured Facilities

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    Offenders accepting contraband cell phones in secured facilities violate state corrections law, and the possession of these cell phones is a form of risk taking behavior. When offenders continue this risky behavior, it affects their decision making in other domains where they are challenging authorities; and may impact the length of their incarceration. This qualitative phenomenological study examined the lived experience of ex-offenders who had contraband cell phones in secured correctional facilities in order to better understand their reasons for taking risks with contraband cell phones. The theoretical foundation for this study was Trimpop\u27s risk-homeostasis and risk-motivation theories that suggest an individual\u27s behaviors adapt to negotiate between perceived risk and desired risk in order to achieve satisfaction. The research question explored beliefs and perceptions of ex-offenders who chose to accept the risk of using contraband cell phones during their time in secured facilities. Data were collected anonymously through recorded telephone interviews with 8 male adult ex-offenders and analyzed using thematic content analysis. Findings indicated participants felt empowered by possession of cell phones in prison, and it was an acceptable risk to stay connected to family out of concern for loved ones. The study contributes to social change by providing those justice system administrators, and prison managers responsible for prison cell phone policies with more detailed information about the motivations and perspectives of offenders in respect to using contraband cell phones while imprisoned in secured facilities

    Proposal for a NbPy-based superconducting spin-valve

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    Superconducting critical temperature, Tc, in proximity coupled Nb/Py/Nb trilayers with Py thickness dPy = 20–432 nm is investigated as a function of the magnetic history of the samples. An enhancement of Tc is observed when an ordered pattern of magnetic stripe domains is induced in the Py layer, namely for dPy > 300 nm. This result is interpreted as a manifestation of the domain-wall superconductivity effect. The possibility to exploit these results for the design of a NbPy-based superconducting spin-valve is discusse

    Topological magnetic irreversibility in superconducting Pb samples of various shapes

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    The magnetic-field dependence of the magnetization of cylinders, disks, and spheres of pure type-I superconducting lead was investigated by means of isothermal measurements of first magnetization curves and hysteresis cycles. Depending on the geometry of the sample and the direction and intensity of the applied magnetic field, the intermediate state exhibits different irreversible features that become particularly highlighted in minor hysteresis cycles. The irreversibility is noticeably observed in cylinders and disks only when the magnetic field is parallel to the axis of revolution and is very subtle in spheres. When the magnetic field decreases from the normal state, the irreversibility appears at a temperature-dependent value whose distance to the thermodynamic critical field depends on the sample geometry. The irreversible features in the disks are altered when they are submitted to an annealing process. These results agree well with very recent high-resolution magneto-optical experiments in similar materials that were interpreted in terms of transitions between different topological structures for the flux configuration in the intermediate state. A discussion of the relative role of geometrical barriers for flux entry and exit and pinning effects as responsible for the magnetic irreversibility is given

    Magnetic properties of double exchange biased diluted magnetic alloy/ferromagnet/antiferromagnet trilayers

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    The magnetic properties of trilayers consisting of a diluted magnetic alloy, CuMn (Cu0:99Mn0:01), a soft ferromagnet, Py(Ni0:8Fe0:2), and an antiferromagnet, -Fe2O3, were investigated. The samples, grown by UHV magnetron sputtering, were magnetically characterized in the temperature range T D 3–100 K. Typical exchange bias features, namely clear hysteresis cycle shifts and coercivity enhancements, were observed. Moreover the presence of an inverse bias, which had been already reported for spin glass-based structures, was also obtained in a well-defined range of temperatures and CuMn thicknesses
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