How hole defects modify vortex dynamics in ferromagnetic nanodisks

Defects introduced in ferromagnetic nanodisks may deeply affect the structure and dynamics of stable vortex-like magnetization. Here, analytical techniques are used for studying, among other dynamical aspects, how a small cylindrical cavity modify the oscillatory modes of the vortex. For instance, we have realized that if the vortex is nucleated out from the hole its gyrotropic frequencies are shifted below. Modifications become even more pronounced when the vortex core is partially or completely captured by the hole. In these cases, the gyrovector can be partially or completely suppressed, so that the associated frequencies increase considerably, say, from some times to several powers. Possible relevance of our results for understanding other aspects of vortex dynamics in the presence of cavities and/or structural defects are also discussed.Comment: 9 pages, 4 page

Two-species fermion mixtures with population imbalance

We analyze the phase diagram of uniform superfluidity for two-species fermion mixtures from the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) limit as a function of the scattering parameter and population imbalance. We find at zero temperature that the phase diagram of population imbalance versus scattering parameter is asymmetric for unequal masses, having a larger stability region for uniform superfluidity when the lighter fermions are in excess. In addition, we find topological quantum phase transitions associated with the disappearance or appearance of momentum space regions of zero quasiparticle energies. Lastly, near the critical temperature, we derive the Ginzburg-Landau equation, and show that it describes a dilute mixture of composite bosons and unpaired fermions in the BEC limit.Comment: 4 pages with 3 figures, accepted version to PR

INFORMED CONSENT OF WOMEN ATTENDED BY STUDENTS OF MEDICINE PERFORMING GYNECOLOGICAL EXAMINATION IN OBSTETRICS AND GYNECOLOGY CLINIC OF FUNDAÇÃO SANTA CASA DE MISERICÓRDIA DO PARÁ

Introdução: As aulas práticas são fundamentais para a formação médica. Entretanto, matérias como Ginecologia e Obstetrícia, o exame físico é profundamente íntimo, lidando com áreas do corpo humano, na qual imperam preconceitos e tabus. Objetivo: Avaliar o sentimento das mulheres atendidas por graduandos de medicina em um hospital de ensino de referência no estado do Pará. Método: O estudo foi realizado nos meses de março a abril de 2013, com uma casuística de 110 mulheres atendidas por graduandos de medicina em ambulatório de ginecologia e obstetrícia de um hospital de ensino. Resultados: A maioria das mulheres deste estudo obtiveram esclarecimentos acerca do exame ginecológico a ser executado (79%) e alegam que foi solicitado consentimento para realização do exame (58%), que ocorreu sem dor ou desconforto (55%), sendo que a 66% dos graduandos prosseguiu na realização do exame na presença da dor ou desconforto. Após a realização do mesmo 41% das mulheres referiu sentir vergonha e as que não receberam esclarecimento revelaram que se sentiriam melhor (48%) ou indiferente (48%) caso recebessem. 62% referiram não ser solicitada a participação do graduando durante exame, porem sua conduta foi considerada adequada (64%), sendo o ambiente serio durante a realização do exame (65%). 55% das mulheres referem ter conhecimento do caráter acadêmico do hospital de ensino. Conclusão: A maioria das mulheres obteve esclarecimento acerca do exame ginecológico, principalmente pelo médico preceptor, alegam que foi requerido consentimento para realização do exame, e não foi questionada a participação do graduando durante o mesmo

Predicted defect induced vortex core switching in thin magnetic nanodisks

We investigate the influence of artificial defects (small holes) inserted into magnetic nanodisks on the vortex core dynamics. One and two holes (antidots) are considered. In general, the core falls into the hole but, in particular, we would like to remark an interesting phenomenon not yet observed, which is the vortex core switching induced by the vortex-hole interactions. It occurs for the case with only one hole and for very special conditions involving the hole size and position as well as the disk size. Any small deformation in the disk geometry such as the presence of a second antidot changes completely the vortex dynamics and the vortex core eventually falls into one of the defects. After trapped, the vortex center still oscillates with a very high frequency and small amplitude around the defect center.Comment: 11pages, Revtex format, 17 figure

Single observable concurrence measurement without simultaneous copies

We present a protocol that allows us to obtain the concurrence of any two qubit pure state by performing a minimal and optimal tomography of one of the subsystems through measuring a single observable of an ancillary four dimensional qudit. An implementation for a system of trapped ions is also proposed, which can be achieved with present day experimental techniques.Comment: 4 pages, 1 figur

The mechanism of action of antimicrobial peptides : lipid vesicles vs. bacteria

Copyright © 2012 Melo and Castanho. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.The authors acknowledge the European FP7-PEOPLE-2009-IEF-254559 grant to Manuel N. Melo and the Fundação para a Ciência e a Tecnologia (Portugal) project PTDC/QUI-BIQ/112929/2009

Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields

Assuming that the order parameter corresponds to an equal spin triplet pairing symmetry state, we calculate the effect of phase fluctuations in quasi-one-dimensional superconductors at high magnetic fields applied along the y (b') axis. We show that phase fluctuations can destroy the theoretically predicted triplet reentrant superconducting state, and that they are responsible for melting the magnetic field induced Josephson vortex lattice above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur

F-wave versus P-wave Superconductivity in Organic Conductors

Current experimental results suggest that some organic quasi-one-dimensional superconductors exhibit triplet pairing symmetry. Thus, we discuss several potential triplet order parameters for the superconducting state of these systems within the functional integral formulation. We compare weak spin-orbit coupling $f_{xyz}$, $p_x$, $p_y$ and $p_z$ symmetries via several thermodynamic quantities. For each symmetry, we analyse the temperature dependences of the order parameter, condensation energy, specific heat, and superfluid density tensor.Comment: 5 pages, 4 figure

Simbiose micorrízica em plantas forrageiras.

Esse projeto teve como objetivos: verificar a condição micorrízica em plantas forrageiras nas condições do semi-árido, avaliar a eficiência de fungos micorrízicos arbusculares em promover o crescimento vegetal e o teor nutricional de plantas de Cajanus cajan var. Petrolina, passível de utilização na alimentação animal, e conhecer o potencial dessas forragens em incrementar a propagação desses fungos no solo