9,594 research outputs found

    Prótesis de rodilla externa mecatrónica

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    Se diseña un mecanismo de articulación de rodilla para una prótesis externa, es decir el prototipo puede ser usado en personas con amputaciones del tipo transfemoral, con el fin de contribuir a la sociedad al brindar soluciones a favor de las personas con capacidades especiales. Se toma en consideración los aspectos más relevantes para el desarrollo de la marcha humana protésica normal como son: nivel de actividad física, medidas antropométricas, materiales adecuados para la construcción, estabilidad y confort entre otros. Luego de realizar un análisis extensivo y proceso de diseño y rediseño se construyó un prototipo funcional, que en el futuro podrá ser probado en personas que así lo requieran.Peer Reviewe

    Cosmological Equation of State and Interacting Energies

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    In this paper we study a model of cosmic evolution, assuming that the different components of the universe could interact between them any time. An effective equation of state (EOS) for the universe has been used as well. A particular function for w, which gives a good agreement between our results and the experimental data, has been studied. Finally, the model obtained has been applied to different important cases

    The algebraic Bethe ansatz for open vertex models

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    We present a unified algebraic Bethe ansatz for open vertex models which are associated with the non-exceptional A2n(2),A2n1(2),Bn(1),Cn(1),Dn(1)A^{(2)}_{2n},A^{(2)}_{2n-1},B^{(1)}_n,C^{(1)}_n,D^{(1)}_{n} Lie algebras. By the method, we solve these models with the trivial K matrix and find that our results agree with that obtained by analytical Bethe ansatz. We also solve the Bn(1),Cn(1),Dn(1)B^{(1)}_n,C^{(1)}_n,D^{(1)}_{n} models with some non-trivial diagonal K-matrices (one free parameter case) by the algebraic Bethe ansatz.Comment: Latex, 35 pages, new content and references are added, minor revisions are mad

    Waiting times in design process: a case study

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    This research focuses on identifying waiting times in design process. This comprised the application of value stream mapping to identify existing flows and design waiting times. From this diagnosis, it was possible to propose recommendations reducing identified waste of time. This study demonstrates the viability of using the value stream mapping and to improve the architectural design process

    Respostas fisiológicas de cabras leiteiras criadas na região litorânea do estado do Ceará.

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    Esse estudo foi conduzido no sitio Acuã na região litorânea do estado do Ceará no período de junho a dezembro de 2000 com o objetivo de avaliar as variações nas concentrações hormonais de T3 e T4 de cabras leiteiras em diferentes épocas de coletas. Foram utilizadas 22 fêmeas caprinas das raças Saanen (n=1O), 1/2 Murciana (n=8), Alpina Americana (n=4) com idade variando entre I a 5 anos e entre a 1a e 4a parição. Na indução do estro foram utilizadas esponjas intra - vaginais de cloprostenol e gonadotrofina eqüina. Não houve efeito significativo entre as variáveis meteorológicas com a temperatura retal e a freqüência respiratória. As concentrações plasmáticas dos hormônios T4 não foram significativas entre raças. O nível hormonal de T3 foi menor nos animais das raças Alpinas Americanas e os valores da TR e FR foram maiores que nas cabras da raça Saanen. Essa resposta adaptativa dos animais da raça Saanen deve-se a aclimatação as condições ambientais da região. Os níveis séricos dos hormônios tireoideanos foram afetados pelas variáveis ambientais porém os animais mantiveram a homeotermia não ocorrendo o estresse térmico.Disponível em separata

    Dependence of the flux creep activation energy on current density and magnetic field for MgB2 superconductor

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    Systematic ac susceptibility measurements have been performed on a MgB2_2 bulk sample. We demonstrate that the flux creep activation energy is a nonlinear function of the current density U(j)j0.2U(j)\propto j^{-0.2}, indicating a nonlogarithmic relaxation of the current density in this material. The dependence of the activation energy on the magnetic field is determined to be a power law U(B)B1.33U(B)\propto B^{-1.33}, showing a steep decline in the activation energy with the magnetic field, which accounts for the steep drop in the critical current density with magnetic field that is observed in MgB2_2. The irreversibility field is also found to be rather low, therefore, the pinning properties of this new material will need to be enhanced for practical applications.Comment: 11 pages, 6 figures, Revtex forma

    Soroepidemiologia do lentivirus em ovinos no Semiárido baiano.

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    [Epidemiology of small ruminant lentiviruses in sheep semiarid of Bahia]. Abstract: To verify the occurrence of antibodies against SRLV in sheep flocks from farms located in Microregion of Feira de Santana, Bahia, we performed a seroepidemiological survey of 10 municipalities with the most effective micro sheep: Antonio Cardoso, Feira de Santana, Ipecaetá , Ipirá, Itatim, Pintadas, Rafael Jambeiro, Santa Terezinha, Santo Estevão e Serra Preta, totaling 384 samples collected from 48 municipalities visited properties. The samples were subjected to the test of agar gel immunodiffusion (AGID) to give negative results in all sera investigated. This finding can be attributed to the composition of herds, which are mostly of animals breed, the system of creation predominantly semi-extensive and type of exploitation for meat, which reduced the risk of introduction of lentivirus . Therefore, in order to preserve the genetic material already adapted to semi-arid climatic adversities, sanitary measures can be taken to prevent the entry of infectious agents circulating in these herds. This is necessary especially because of the tendencies of improving the productivity of small ruminant animals by the introduction of imported breed

    Direct Discharges of Domestic Wastewater are a Major Source of Phosphorus and Nitrogen to the Mediterranean Sea

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    Direct discharges of treated and untreated wastewater are important sources of nutrients to coastal marine ecosystems and contribute to their eutrophication. Here, we estimate the spatially distributed annual inputs of phosphorus (P) and nitrogen (N) associated with direct domestic wastewater discharges from coastal cities to the Mediterranean Sea (MS). According to our best estimates, in 2003 these inputs amounted to 0.9 × 10⁹ mol P yr-1 and 15 × 10⁹ mol N yr-1, that is, values on the same order of magnitude as riverine inputs of P and N to the MS. By 2050, in the absence of any mitigation, population growth plus higher per capita protein intake and increased connectivity to the sewer system are projected to increase P inputs to the MS via direct wastewater discharges by 254, 163, and 32% for South, East, and North Mediterranean countries, respectively. Complete conversion to tertiary wastewater treatment would reduce the 2050 inputs to below their 2003 levels, but at an estimated additional cost of over €2 billion yr-1. Management of coastal eutrophication may be best achieved by targeting tertiary treatment upgrades to the most affected near-shore areas, while simultaneously implementing legislation limiting P in detergents and increasing wastewater reuse across the entire basin
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