2,949 research outputs found

    Expression of a hantavirus N protein and its efficacy as antigen in immune assays

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    Hantavirus cardiopulmonary syndrome (HCPS) has been recognized as an important public heath problem. Five hantaviruses associated with HCPS are currently known in Brazil: Juquitiba, Araraquara, Laguna Negra-like, Castelo dos Sonhos, and Anajatuba viruses. The laboratory diagnosis of HCPS is routinely carried out by the detection of anti-hantavirus IgM and/or IgG antibodies. The present study describes the expression of the N protein of a hantavirus detected in the blood sample of an HCPS patient. The entire S segment of the virus was amplified and found to be 1858 nucleotides long, with an open reading frame of 1287 nucleotides that encodes a protein of 429 amino acids. The nucleotide sequence described here showed a high identity with the N protein gene of Araraquara virus. The entire N protein was expressed using the vector pET200D and the Escherichia coli BL21 strain. The expression of the recombinant protein was confirmed by the detection of a 52-kDa protein by Western blot using a pool of human sera obtained from HCPS patients, and by specific IgG detection in five serum samples of HCPS patients tested by ELISA. These results suggest that the recombinant N protein could be used as an antigen for the serological screening of hantavirus infection.FAPES

    Estimating Self-Sustainability in Peer-to-Peer Swarming Systems

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    Peer-to-peer swarming is one of the \emph{de facto} solutions for distributed content dissemination in today's Internet. By leveraging resources provided by clients, swarming systems reduce the load on and costs to publishers. However, there is a limit to how much cost savings can be gained from swarming; for example, for unpopular content peers will always depend on the publisher in order to complete their downloads. In this paper, we investigate this dependence. For this purpose, we propose a new metric, namely \emph{swarm self-sustainability}. A swarm is referred to as self-sustaining if all its blocks are collectively held by peers; the self-sustainability of a swarm is the fraction of time in which the swarm is self-sustaining. We pose the following question: how does the self-sustainability of a swarm vary as a function of content popularity, the service capacity of the users, and the size of the file? We present a model to answer the posed question. We then propose efficient solution methods to compute self-sustainability. The accuracy of our estimates is validated against simulation. Finally, we also provide closed-form expressions for the fraction of time that a given number of blocks is collectively held by peers.Comment: 27 pages, 5 figure

    Tratamiento conservador del hallux valgus juvenil mediante ortesis nocturnas

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    Se presentan los resultados obtenidos con tratamiento conservador del hallux valgus juvenil con el uso de ortesis nocturnas confeccionadas a medida, con material termoplástico, en 18 pacientes con edades de 8 a 15 años (media: 12 años). El tiempo medio de tratamiento fue de 18 meses y los pacientes fueron seguidos después del tratamiento por igual período de tiempo. Debe destacarse el alto abandono del método que alcanzó la cifra del 44%. Fueron utilizados como parámetros de valoración de resultados las medidas radiográficas de los ángulos de valguismo del hallux (AVH) e intermetatarsiano l-II (AIM), obtenidas antes y después de terminado el período de observación. El valor medio inicial del AVH fue de 22° y al final fue de 20°. Las medidas de los valores del AIM fueron 11 y 10,7°, respectivamente. Ambas medidas no se diferencian entre sí desde el punto de vista estadístico, lo que lleva a concluir que el tratamiento utilizado no fue capaz de corregir las deformidades básicas del hallus valgus infantil, pero evita la progresión de esas deformidades.The results of conservative treatment of adolescent hallux valgus using custom made nocturnal splints in 18 patients ranging in age from 8 to 15 years (mean 12) are presented. The average period of treatment and follow-up was 18 months. There was a high rate (44%) of treatment abandon. As assessment parameters were used radiographic measures of the hallux valgus angle and the intermetatarsal I-II angle. Measures were obtained before treatment and at the end of follow-up. The initial mean valgus angle was 22° and the last mean value 20°. The mean valus of the intermetatarsal angle were respectively 11° and 10,7°. There were no significant statistical differences, indicating that the treatment of hallux valgus using nocturnal splintage do not correct the deformity but avoid its progression

    Development of SNPs markers (single nucleotide polymorphisms) presents in regulatory regions and genotyping of mapping population Hevea brasiliensis

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    The rubber tree (Hevea spp.), primary plant used for natural rubber production, have a long breeding cycle. However, the advent of molecular genetic markers favored early assessment methods, allowing the characterization of genotypes, genetic diversity analysis, QTL analysis and identifying genes of interest. In this context, this work aimed at the development and genotyping of new SNP markers presents in regulatory regions in two populations of genetic mapping of rubber tree. The raw data for each pool of samples (GT1 and RRIM701 genotypes) were separately trimmed and de novo assembled in a unique file using the CLC Genomics Workbench software (Version 6.0.1, CLC Bio, Denmark). Next, BWA aligned short reads back to assembled contigs, and Freebayes was used to perform variant calling and SNP detection. Using the varFilter command of vcfutils script, SNPs were filtered only for positions with a minimal mapping quality and coverage of 30 and 10 respectively. Unique and shared SNPs among the two cultivars were extracted with the VCFtools software. The selected SNPs annotation was made in two databases of cis regions: PLACE and ALGEEN-PROMO. Identification of SNP allelic forms was performed using KASPAR chemistry, either with PCR final point analysis on rtPCR equipment (LC480) for testing the polymorphism of the parents, or with Fluidigm technology for progeny genotyping. We obtained an average of 76% success rate in genotyping. The results will be used for saturation of molecular genetic map of H. brasiliensis, the location of these cis regions mutated on the map. (Résumé d'auteur

    Consistency analysis of a nonbirefringent Lorentz-violating planar model

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    In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor κμν\kappa_{\mu\nu}. The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for 0κ00<10\leq\kappa_{00}<1. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a λφ4\lambda|\varphi|^{4}-Higgs field supports compactlike vortex configurations.Comment: 11 pages, revtex style, final revised versio

    Theory of Disordered Itinerant Ferromagnets I: Metallic Phase

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    A comprehensive theory for electronic transport in itinerant ferromagnets is developed. We first show that the Q-field theory used previously to describe a disordered Fermi liquid also has a saddle-point solution that describes a ferromagnet in a disordered Stoner approximation. We calculate transport coefficients and thermodynamic susceptibilities by expanding about the saddle point to Gaussian order. At this level, the theory generalizes previous RPA-type theories by including quenched disorder. We then study soft-mode effects in the ferromagnetic state in a one-loop approximation. In three-dimensions, we find that the spin waves induce a square-root frequency dependence of the conductivity, but not of the density of states, that is qualitatively the same as the usual weak-localization effect induced by the diffusive soft modes. In contrast to the weak-localization anomaly, this effect persists also at nonzero temperatures. In two-dimensions, however, the spin waves do not lead to a logarithmic frequency dependence. This explains experimental observations in thin ferromagnetic films, and it provides a basis for the construction of a simple effective field theory for the transition from a ferromagnetic metal to a ferromagnetic insulator.Comment: 15pp., REVTeX, 2 eps figs, final version as publishe

    Electron localization : band-by-band decomposition, and application to oxides

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    Using a plane wave pseudopotential approach to density functional theory we investigate the electron localization length in various oxides. For this purpose, we first set up a theory of the band-by-band decomposition of this quantity, more complex than the decomposition of the spontaneous polarization (a related concept), because of the interband coupling. We show its interpretation in terms of Wannier functions and clarify the effect of the pseudopotential approximation. We treat the case of different oxides: BaO, α\alpha-PbO, BaTiO3_3 and PbTiO3_3. We also investigate the variation of the localization tensor during the ferroelectric phase transitions of BaTiO3_3 as well as its relationship with the Born effective charges

    Some exact solutions of F(R) gravity with charged (a)dS black hole interpretation

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    In this paper we obtain topological static solutions of some kind of pure F(R)F(R) gravity. The present solutions are two kind: first type is uncharged solution which corresponds with the topological (a)dS Schwarzschild solution and second type has electric charge and is equivalent to the Einstein-Λ\Lambda-conformally invariant Maxwell solution. In other word, starting from pure gravity leads to (charged) Einstein-Λ\Lambda solutions which we interpreted them as (charged) (a)dS black hole solutions of pure F(R)F(R) gravity. Calculating the Ricci and Kreschmann scalars show that there is a curvature singularity at r=0r=0. We should note that the Kreschmann scalar of charged solutions goes to infinity as r0r \rightarrow 0, but with a rate slower than that of uncharged solutions.Comment: 21 pages, 4 figures, generalization to higher dimensions, references adde
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