10,748 research outputs found

    Spider diversity (Arachnida: Araneae) in Atlantic Forest areas at Pedra Branca State Park, Rio de Janeiro, Brazil

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    BACKGROUND: There has never been any published work about the diversity of spiders in the city of Rio de Janeiro using analytical tools to measure diversity. The only available records for spider communities in nearby areas indicate 308 species in the National Park of Tijuca and 159 species in Marapendi Municipal Park. These numbers are based on a rapid survey and on an one-year survey respectively. NEW INFORMATION: This study provides a more thorough understanding of how the spider species are distributed at Pedra Branca State Park. We report a total of 14,626 spider specimens recorded from this park, representing 49 families and 373 species or morphospecies, including at least 73 undescribed species. Also, the distribution range of 45 species was expanded, and species accumulation curves estimate that there is a minimum of 388 (Bootstrap) and a maximum of 468 species (Jackknife2) for the sampled areas. These estimates indicates that the spider diversity may be higher than observed.Fil: Castanheira, Pedro. Universidade Federal do Rio de Janeiro; BrasilFil: Pérez González, Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Baptista, Renner L. C.. Universidade Federal do Rio de Janeiro; Brasi

    Strain mapping and nanocrystallite size determination by neutron diffraction in an aluminum alloy (AA5083) severely plastically deformed through equal channel angular pressing

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    Six specimens of an aluminum alloy (AA-5083) extruded by Equal Channel Angular Pressing following two different routes plus a blank sample were examined with a neutron radiation of 1.5448 Å. Macrostrain maps from the (311) reflection were obtained. A clear difference about accumulated macrostrain with the extrusion cycles between the two routes is shown. The diffraction data of annealed specimens did permit to estimate crystallite sizes that range between 89 nm and 115 nm depending on the routes

    Vector magnetic hysteresis of hard superconductors

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    Critical state problems which incorporate more than one component for the magnetization vector of hard superconductors are investigated. The theory is based on the minimization of a cost functional C[H(x)]{\cal C}[\vec{H}(\vec{x})] which weighs the changes of the magnetic field vector within the sample. We show that Bean's simplest prescription of choosing the correct sign for the critical current density JcJ_c in one dimensional problems is just a particular case of finding the components of the vector Jc\vec{J}_c. Jc\vec{J}_c is determined by minimizing C{\cal C} under the constraint JΔ(H,x)\vec{J}\in\Delta (\vec{H},\vec{x}), with Δ\Delta a bounded set. Upon the selection of different sets Δ\Delta we discuss existing crossed field measurements and predict new observable features. It is shown that a complex behavior in the magnetization curves may be controlled by a single external parameter, i.e.: the maximum value of the applied magnetic field HmH_m.Comment: 10 pages, 9 figures, accepted in Phys. Rev.

    Prótesis total de cadera con poropatita: Resultados a 12 años

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    El trabajo analiza 150 prótesis totales de cadera, con un seguimiento de 12 años. En todos los pacientes se implantaron los componentes de Poropatita fabricados con aleación de Titanio y recubiertos de Poropatita. La edad de los pacientes oscilo entre los 25 y 85 años, con una media de 61 años, y en las revisiones posteriores realizadas, tanto clínica como radiográficamente, se observó una rápida integración de los implantes con áreas de osteoconducción y osteointegración evidentes.We reviewed 150 hip arthroplasties with a follow-up of 12 years. In all patients we used the components made of a titanium alloy with poropatita. The average age of the patients was 85 years (range 25-85 years). The follow-up period showed good clinical outcome, and radiographic parameters disclosed excellent integration of the implants with areas of osteoconduction and osteointegration

    Tratamiento de la pseudoartrosis con P15

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    La reconstrucción de los defectos óseos, es un problema que se plantea con frecuencia en Cirugía Traumatológica. El objetivo de este trabajo esa evaluar la regeneración ósea en paciente con retardo de consolidación de fracturas de húmero y tibia, utilizando un factor de crecimiento (P15 combinado con Hidroxiapatita) y observar la respuesta osteoinductiva de la regeneración ósea. Se intervinieron quirúrgicamente 12 pacientes, con un seguimiento mínimo de 2 años. Describimos la metodología en cuanto a técnica y control post-operatorio y valoramos el estado clínico, radiológico e histológico. Los resultados fueron muy buenos en 10 casos. El P15 combinado con la Hidroxiapatita, ha permitido ver una respuesta osteoconductiva y osteoinductiva en los defectos óseos, con un futuro presumiblemente prometedor en Cirugía Ortopédica.The reconstruction of bone defects is a problem in the current orthopaedic surgery practice. The object of this study is to evaluate the regeneration in bones defects under the influence of a growth factor (P15 combined with hidroxyapatite), recording the evidence of osteo-inductive activity. Twelve patients with bone defects were operated with a minimal follow up of two years, we detailed the technique and postoperative management of the patients. Clinical, radiology and histology results were assessed, with excellent outcome in 10 cases. The P15 combined with Hidroxyapatite has allowed for a bone conductive and inductive response in bones defects

    Formation of atom wires on vicinal silicon

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    The formation of atomic wires via pseudomorphic step-edge decoration on vicinal silicon surfaces has been analyzed for Ga on the Si(112) surface using Scanning Tunneling Microscopy and Density Functional Theory calculations. Based on a chemical potential analysis involving more than thirty candidate structures and considering various fabrication procedures, it is concluded that pseudomorphic growth on stepped Si(112), both under equilibrium and non-equilibrium conditions, must favor formation of Ga zig-zag chains rather than linear atom chains. The surface is non-metallic and presents quasi-one dimensional character in the lowest conduction band.Comment: submitte

    Efficiency of Livestock Residue Treatment in Geomembrane Digesters

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    The efficiency of twelve 10 m3 geomembrane biodigesters to treat swine and cattle residuals was assessed. The study took place at the Cooperative of Credits and Services (CCS) of the municipality of Cumanayagua, Cienfuegos, Cuba. Its goal was to evaluate feasibility of technology implementation in Cuba.  The effluent physical and chemical indicators were determined at entry and exit from biodigesters. The biodigesters charged with pig manure were able to remove 75.88% COD, and up to 66-44% SS. Besides, 64.79% of the contaminating organic load was converted into volatile products during biofermentation. Meanwhile, the biodigesters charged with cattle manure removed 60.42% of COD, and up to 67.67% of SS; 61.51% of the organic contaminating load was converted in volatile products. It was concluded that the biodigesters had acceptable efficiency values, and that the technology can be applied in Cuba.   
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