Vortex phases in mesoscopic cylinders with suppressed surface superconductivity

Vortex structures in mesoscopic cylinder placed in external magnetic field are studied under the general de Gennes boundary condition for the order parameter corresponding to the suppression of surface superconductivity. The Ginzburg-Landau equations are solved based on trial functions for the order parameter for vortex-free, single-vortex, multivortex, and giant vortex phases. The equilibrium vortex diagrams in the plane of external field and cylinder radius and magnetization curves are calculated at different values of de Gennes "extrapolation length" characterizing the boundary condition for the order parameter. The comparison of the obtained variational results with some available exact solutions shows good accuracy of our approach.Comment: RevTex, 11 pages, 10 figure

MIOPLASTIA EXPERIMENTAL DO ESFÍNCTER ANAL EXTERNO COM Fascia lata AUTÓLOGA, EM CÃES

A incontinência fecal em cães e gatos é uma situação na qual o proprietário tem dificuldades para resolver as conseqüências advindas desta lesão, e geralmente os pacientes são submetidos à eutanásia. Algumas técnicas cirúrgicas empregadas na esfincteroplastia são passíveis de complicações como estenose anal ou incontinência fecal. Este experimento teve como objetivo reconstituir o músculo esfíncter anal externo em cães, após iatrogenização da incontinência fecal. Foram utilizados 10 cães hígidos, machos, sem raça definida, com peso variando entre 9 a14 kg. Após incisão de pele circundando a abertura anal, procedeu-se a miectomia bilateral de esfíncter anal externo, iatrogenizando-se a incontinência fecal, a qual foi diagnosticada por meio de avaliação física diária. Trinta dias após, os pacientes foram novamente preparados para cirurgia asséptica e submetidos à esfincteroplastia anal externa com o uso de Fascia lata autológa medindo 8 cm de comprimento e 0,5 cm de largura, em média. Os dez cães incontinentes, em decorrência da miectomia do esfíncter anal externo, apresentaram controle da emissão de fezes em 10 dias após a realização da esfincteroplastia e mantiveram-se assim durante os dois meses de observação póscirúrgica. Dessa maneira concluiu-se que a mioplastia do esfíncter anal externo com Fascia lata autóloga, representa um procedimento eficaz de simples e rápida aplicação, podendo ser utilizado rotineiramente para restabelecer a continência fecal em cães. Experimental myoplasty of the external anal sphincter with autologous Fascia lata in dogs Abstract Fecal incontinence in dogs and cats is a hard condition for owners to solve the consequences of this lesion, being patients usually subjected to euthanasia. Some surgical techniques used in sphincteroplasty are prone to complications such as anal stenosis or fecal incontinence. This experiment objectified to reconstruct the external anal sphincter in dogs after iatrogeny of the fecal incontinence. Ten healthy male dogs of undefined breed, weight ranging from 9 to 14 kg, were used. After dermal incision surrounding the anal opening, bilateral myectomy of the external anal sphincter was performer, with iatrogeny of fecal incontinence, diagnosed by daily physical evaluation. Thirty days later, patients were again prepared for aseptic surgery and went under external anal sphincteroplasty using autologous Fascia lata averaging 8 cm long and 0,5 cm wide. Ten incontinent dogs, due to external anal sphincter myectomy, presented fecal control in ten days after surgery and for the two subsequent months of follow-up. In conclusion, myoplasty of external anal sphincter using autologous Fascia lata is a simple and effective treatment that can be used in fecal incontinence in dogs

Geometric Phase, Curvature, and Extrapotentials in Constrained Quantum Systems

We derive an effective Hamiltonian for a quantum system constrained to a submanifold (the constraint manifold) of configuration space (the ambient space) by an infinite restoring force. We pay special attention to how this Hamiltonian depends on quantities which are external to the constraint manifold, such as the external curvature of the constraint manifold, the (Riemannian) curvature of the ambient space, and the constraining potential. In particular, we find the remarkable fact that the twisting of the constraining potential appears as a gauge potential in the constrained Hamiltonian. This gauge potential is an example of geometric phase, closely related to that originally discussed by Berry. The constrained Hamiltonian also contains an effective potential depending on the external curvature of the constraint manifold, the curvature of the ambient space, and the twisting of the constraining potential. The general nature of our analysis allows applications to a wide variety of problems, such as rigid molecules, the evolution of molecular systems along reaction paths, and quantum strip waveguides.Comment: 27 pages with 1 figure, submitted to Phys. Rev.

Seroprevalence of Toxoplasma gondii infection among veterinary staff in Ontario, Canada (2002): Implications for teratogenic risk

BACKGROUND: Toxoplasma gondii infection is embryotoxic in humans. It is mainly transmitted through raw/undercooked meat and ingestion of oocysts in cat feces. There remains controversy about the actual risk of cats transmitting the disease to humans. Our primary objective was to determine the seroprevalence of T. gondii antibody among veterinary staff, to ascertain whether they have an increased risk through occupational exposure. Our secondary objective was to examine their practices regarding cats, toxoplasma infection, and pregnancy. METHODS: Veterinary staff attending the 2002 Annual Ontario Veterinary Medical Association Conference were invited to discuss their toxoplasma seroprevalence. Interested attendees completed a questionnaire and a physician drew blood samples to determine T. gondii titres using the ELISA IgG test. RESULTS: We collected 161 completed questionnaires, and 141 blood samples. There were 20 (14.2%, CI95%:8.4–19.9%) reactive titres among the veterinarian staff (80% females aged 30–45). All were regularly exposed to cats, washed their hands when in contact and few wore gloves routinely. CONCLUSIONS: These findings of low positive rates may be used to reassure veterinary staff that their exposure to cats does not appear to increase their risk of contracting toxoplasma infection and that pregnant women are not at an increased risk by owning a cat