Tunable critical current for a vortex pinned by a magnetic dipole

\\A simple model for a superconductor with tunable critical current is studied theoretically. The model consists of a thin superconducting film with one vortex interacting with one magnetic dipole, whose magnetic moment is free to rotate, in the presence of a magnetic field applied parallel to the film surfaces. The pinning potential for the vortex is calculated exactly in the London limit. It is found that, due to the dipole freedom to rotate, the dependence of the pinning potential on the applied field is non-trivial, and allows both the spatial dependence and strength of the pinning potential to be changed by the field. As a consequence, the critical current can be tuned by the applied field. The critical current is obtained numerically as a function of the applied field. Order of magnitude changes in the critical current resulting from changes in the direction and magnitude of the applied field are reported, with discontinuous changes taking place in some cases. Possible application to vortices in low-$T_c$ superconducting films pinned by arrays of magnetic dots are briefly considered. \\Comment: 7 pages, 4 figures. To be published in Europhysics Letter

Tunable interactions between vortices and a magnetic dipole

The interactions between vortices in a thin superconducting film and one magnetic dipole in the presence of a magnetic field applied parallel to the film surfaces are studied theoretically in the London limit. The dipole magnetic moment is assumed to have constant magnitude and freedom to rotate. The pinning potential for an arbitrary vortex configuration is calculated exactly. It is found that, due to the dipole freedom to rotate, the pinning potential differs significantly from that for a permanent dipole. In particular, its dependence on the applied field is non-trivial and allows for tuning of the pinning potential by the applied field. The critical current for one vortex pinned by the dipole is obtained numerically as a function of the applied field and found to depend strongly on the field. Order of magnitude changes in the critical current resulting from changes in the direction and magnitude of the applied field are reported, with discontinuous changes taking place in some cases. The effect of vortex pinning by random material defects on the critical current is investigated using a simple model. It is found that if random pinning is weak the critical current remains strongly dependent on the applied field. Possible applications to vortices pinned by arrays of magnetic dots are briefly considered.Comment: 9 pages, 9 figures. Submitted to Phys. Rev.

Force between a magnetic tip and an inhomogeneous superconductor at zero field

The force exerted by a semi-infinite inhomogeneous superconductor with a planar interface to vacuum on a magnetic tip is studied theoretically in the absence of external magnetic fields. It is shown that the force has a contribution from inhomogeneities due to material defects with unique characteristics. Defects are taken into account in the London limit by allowing the mass parameter to vary spatially. The contribution from defects to the force is calculated analytically to first order in the deviation of the mass parameter from its constant value for the homogeneous superconductor, assuming that the tip is a point dipole perpendicular to the interface, and that it does not spontaneously create vortex matter. Random point defects and linear localized defects are considered phenomenologically. For each defect type the force dependence on the dipole position coordinates is obtained, and the force magnitudes are estimated numerically. The predictions for the dependence of the linear defect force on the dipole lateral position are found to agree qualitatively with experiment.Comment: 4 pages, 3 figures, submitted to Physica C - Proceedings VORTEX VI Conferenc

Tunable pinning of a superconducting vortex a by a magnetic vortex

The interaction between a straight vortex line in a superconducting film and a soft magnetic nanodisk in the magnetic vortex state in the presence of a magnetic field applied parallel to the film surfaces is studied theoretically. The superconductor is described by London theory and the nanodisk by the Landau-Lifshitz continuum theory of magnetism, using the approximation known as the rigid vortex model. Pinning of the vortex line by the nanodisk is found to result, predominantly, from the interaction between the vortex line and the changes in the nanodisk magnetization induced by the magnetic field of the vortex line and applied field. In the context of the rigid vortex model, these changes result from the displacement of the magnetic vortex. This displacement is calculated analytically by minimizing the energy, and the pinning potential is obtained. The applied field can tune the pinning potential by controlling the displacement of the magnetic vortex. The nanodisk magnetization curve is predicted to change in the presence of the vortex lineComment: 9 pages, 8 figures. Submitted to Phys. Rev.

Sexuality of patients with bowel elimination ostomy

Objective: To evaluate the impact of ostomy in the sexuality of an stomized individual. Methods: A descriptive exploratory study with a quantitative approach, developed in an Integrated Health Center in Teresina/PI. Eighty three patients participated, according to the inclusion criteria. Data were collected using a structured form, stored in Excel 2010 and analyzed through descriptive statistics using chi-squared test. Approval from the Research Ethics Committee CAAE No. 36551714.0.0000.5512 was obtained. Results: Three sections were obtained. The first section, referring to the profile of the sample, includes sociodemographic features of patients with intestinal elimination ostomy; the second section features their sexuality; and the third section lists the sociodemographic characteristics and related to the characteristics of sexuality. Conclusion: Having an ostomy influences many factors that contribute to the well-being of people. The change of body image changes the psychic functions, influencing sexual activity

Dynamical Phases of Driven Vortices Interacting with Periodic Pinning

The finite temperature dynamical phases of vortices in films driven by a uniform force and interacting with the periodic pinning potential of a square lattice of columnar defects are investigated by Langevin dynamics simulations of a London model. Vortices driven along the [0,1] direction and at densities for which there are more vortices than columnar defects ($B>B_{\phi}$) are considered. At low temperatures, two new dynamical phases, elastic flow and plastic flow, and a sharp transition between them are identified and characterized according to the behavior of the vortex spatial order, velocity distribution and frequency-dependent velocity correlationComment: 4 pages with 4 figures. To be published in Phys. Rev. B Rapid Communication

Uma proposta histórico-cultural do fazer clínico: relato de experiência em oficinas terapêuticas

Este trabalho trata-se de um registro teórico-prático, descritivo e qualitativo, referente a experiência de Estágio Básico em Psicologia Clínica, da Faculdade Católica Dom Orione. O mesmo ocorreu nas dependências de um Centro de Atenção Psicossocial Infanto-Juvenil (CAPSi). O estágio referido, foi realizado através de observações em oficinas terapêuticas, com público alvo de adolescentes, teve como principal intuito, favorecer a constituição de vínculos entre estagiários, mediadores das oficinas, adolescentes usuários e familiares, levantando as principais demandas ali expostas, e conseguinte elaborar ações de acordo com os embasamentos teóricos da abordagem histórico-cultural, articulando teoria e prática, aspirando a materialização das emoções e vivências do grupo acompanhado, bem como compreender o processo de subjetividade dos adolescentes a partir de um fazer psicológico para além da clínica. No decorrer das observações foi compreendido que existe um distanciamento entre o serviço ideal e o que é ofertado, tornando factível a correlação entre teoria e prática do psicólogo dentro da instituição, considerando que se faz necessário suscitar reflexões respaldadas em experiências pertinentes às ações desenvolvidas nestes espaços, que tem como projeto, um novo modelo de saúde mental, com o propósito de promover um serviço cada vez mais pautado na ética, no respeito e no compromisso social e político, com vistas a reivindicar o direito das pessoas a um serviço cada vez mais preparado para acolher as necessidades individuais de cada um, visando sempre na promoção de saúde