17,806 research outputs found

    P-248 Futility and utility of two-stage hepatectomy

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    Meeting abstract in the European-Society-for-Medical-Oncology (ESMO) 21st World Congress on Gastrointestinal Cancer.info:eu-repo/semantics/publishedVersio

    Obliterative Surgery for Pelvic Organ Prolapse - an Option that Remains Valid?

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    Objective: To investigate the results of vaginal obliterate surgery in elderly women with pelvic organ prolapse. Design: observational retrospective study. Material and Methods: a total of 69 women with the diagnosis of pelvic prolapse were submitted to obliterative surgery in the urogynecology unit of a tertiary care hospital centre over the course of 8 years (2001 to 2008). The following data were collected from their clinical records: age, number of vaginal births, body mass index (BMI), hormone therapy, other existing diseases, type of prolapse and stage, anaesthetic risk score, duration of surgery, length of hospital stay, and short-term complications. Results: Of the 69 women studied, 31 were submitted to colpocleisis and the remaining 38 were managed by the LeFort technique. Mean age was 74.8 years with a standard deviation (sd) of 7.14 years. Average BMI was 26.2 (sd =3.76). Vaginal births were recorded in all patients. Only three patients were taking hormone therapy at the time of surgery. Sixty-three women were classified as having and anesthetic risk of II or III and 55 underwent local-regional anesthesia. Complications were reported in five cases, four of which in the first days after surgery. Nearly all were mild and resolved within the first 6 weeks. Conclusion: Complication rates appear to be low after obliterative surgery for pelvic organ prolapse in elderly women

    The influence of the Al stabilizer layer thickness on the normal zone propagation velocity in high current superconductors

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    The stability of high-current superconductors is challenging in the design of superconducting magnets. When the stability requirements are fulfilled, the protection against a quench must still be considered. A main factor in the design of quench protection systems is the resistance growth rate in the magnet following a quench. The usual method for determining the resistance growth in impregnated coils is to calculate the longitudinal velocity with which the normal zone propagates in the conductor along the coil windings. Here, we present a 2D numerical model for predicting the normal zone propagation velocity in Al stabilized Rutherford NbTi cables with large cross section. By solving two coupled differential equations under adiabatic conditions, the model takes into account the thermal diffusion and the current redistribution process following a quench. Both the temperature and magnetic field dependencies of the superconductor and the metal cladding materials properties are included. Unlike common normal zone propagation analyses, we study the influence of the thickness of the cladding on the propagation velocity for varying operating current and magnetic field. To assist in the comprehension of the numerical results, we also introduce an analytical formula for the longitudinal normal zone propagation. The analysis distinguishes between low-current and high-current regimes of normal zone propagation, depending on the ratio between the characteristic times of thermal and magnetic diffusion. We show that above a certain thickness, the cladding acts as a heat sink with a limited contribution to the acceleration of the propagation velocity with respect to the cladding geometry. Both numerical and analytical results show good agreement with experimental data.Comment: To be published in Physics Procedia (ICEC 25 conference special issue

    Unified model for vortex-string network evolution

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    We describe and numerically test the velocity-dependent one-scale (VOS) string evolution model, a simple analytic approach describing a string network with the averaged correlation length and velocity. We show that it accurately reproduces the large-scale behaviour (in particular the scaling laws) of numerical simulations of both Goto-Nambu and field theory string networks. We explicitly demonstrate the relation between the high-energy physics approach and the damped and non-relativistic limits which are relevant for condensed matter physics. We also reproduce experimental results in this context and show that the vortex-string density is significantly reduced by loop production, an effect not included in the usual `coarse-grained' approach.Comment: 5 pages; v2: cosmetic changes, version to appear in PR

    Educação formal e não formal em ciências

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    Apresenta-se uma estratégia de formação contínua de professores que se desenvolveu no âmbito dum estudo de caso sobre a planificação, concepção e avaliação de um Ambiente Integrado de Educação em Ciências (AIEC) na futura escola 1º CEB de Vila Nova da Barquinha (VNB). Esta escola que irá ser construída de raiz, é um projecto inovador que conta com a colaboração protocolada da Universidade de Aveiro, através de uma equipa de docentes do Departamento de Didáctica e Tecnologia Educativa, da qual a primeira autora faz parte como investigadora. Com este estudo pretende-se, assim perspectivar uma nova forma de organizar o ensino e aprendizagem formal e não-formal das ciências, integrando-os. Tal anseio exige uma formação adequada dos professores que irão leccionar nessa escola, pois serão eles a implementar, com as suas crianças, as actividades Integradas de Educação em Ciencias

    Transformer and LCL Filter Design for DPFCs

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    Flexible AC Transmission Systems (FACTS) can be used for power flow control in AC transmission grids, allowing simultaneous control of the bus voltage and line active and reactive power. However, due to high costs and reliability concerns, the application of this technology has been limited in such applications. Recently, the concept of Distributed FACTS (DFACTS) and Distributed Power Flow Controller (DPFC) has been introduced as a low cost high reliability alternative for power flow control. This paper presents the design of a coupling transformer and a LCL filter for DPFC devices. To extract the electromagnetic energy from the transmission line a transformer with a single turn primary is designed and optimized. A third-order LCL filter is used to guarantee high order harmonics filtering. Simulations results are presented and discussed

    Twenty years of cropping systems and their effects on soil aggregation in the Brazilian Cerrado.

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    The adoption of practices based on the conservation of soil and water may improve soil structural quality upon conversion of conventional tillage system to no-till. In this presentation, we report the results of 20 yr of cropping after this conversion in the Brazilian Cerrado
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