640 research outputs found

    Turing patterns in a p-adic FitzHugh-Nagumo system on the unit ball

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    We introduce discrete and p-adic continuous versions of the FitzHugh-Nagumo system on the one-dimensional p-adic unit ball. We provide criteria for the existence of Turing patterns. We present extensive simulations of some of these systems. The simulations show that the Turing patterns are traveling waves in the p-adic unit ball.Comment: Final version accepted in p-Adic Numbers, Ultrametric Analysis and Application

    Turing patterns in a p-adic FitzHugh-Nagumo system on the unit ball

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    We introduce discrete and p-adic continuous versions of the FitzHugh-Nagumo system on the one-dimensional p-adic unit ball. We provide criteria for the existence of Turing patterns. We present extensive simulations of some of these systems. The simulations show that the Turing patterns are traveling waves in the p-adic unit ball

    Local well-posedness of the Cauchy problem for a p-adic Nagumo-type equation

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    We introduce a new family of p-adic non-linear evolution equations. We establish the local well-posedness of the Cauchy problem for these equations in Sobolev-type spaces. For a certain subfamily, we show that the blow-up phenomenon occurs and provide numerical simulations showing this phenomenon

    Efecto del contenido de aluminato de estroncio y hemihidrato sobre las propiedades de un cemento de sulfoaluminato de calcio

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    The effect of strontium aluminate (SrAl2O4) on the hydration process of a calcium sulphoaluminate (C4A3Ŝ) cement was investigated. Cement pastes were prepared by mixing C4A3Ŝ , hemihydrate (CaSO4· ½H2O, CŜH0.5) and 0, 10 or 20wt% of SrAl2O4 (SrA). The amount of CŜH0.5 was 15, 20 or 25wt% based on the C4A3Ŝ quantity. The cement pastes were hydrated using water to cement ratios (w/c) of 0.4 and 0.5. Samples were cured from 1 to 28 d. The compressive strength and setting time were evaluated and the hydration products were characterized. It was found that the setting time was delayed up to 42 min for the samples containing SrAl2O4 compared to samples without addition. The samples with 25wt% hemihydrate containing 20wt% SrAl2O4 developed the highest compressive strength (60 MPa) after 28 d of curing. The main product after hydration was ettringite (C6AŜ3H32). The morphology of this phase consisted of thin needle-shaped crystals.Se investigó el efecto de la adición de aluminato de estroncio (SrAl2O4) sobre las propiedades de un cemento de sulfoaluminato de calcio (C4A3Ŝ). Se prepararon muestras mezclando C4A3Ŝ, hemihidrato (CaSO4· ½H2O, CŜH0.5) y 0, 10 o 20% e.p de SrAl2O4 (SrA). La cantidad de CŜH0.5 fue de 15, 20 o 25% e.p. basado en la cantidad de C4A3Ŝ. Las relaciones agua/cemento utilizadas fueron 0.4 y 0.5. Las muestras fueron curadas hasta 28 d. Se evaluó el tiempo de fraguado y la resistencia a la compresión. Los productos de hidratación se caracterizaron mediante DRX y MEB. El tiempo de fraguado se retardó hasta 42 minutos con la adición del SrAl2O4 comparado con las muestras sin adiciones. Las muestras con 25% e.p. de yeso y 20% e.p. de SrAl2O4 desarrollaron la mayor resistencia a la compresión alcanzando 60 MPa a 28 d de curado. Los análisis por MEB y DRX muestran como principal producto de hidratación a la etringita (C6AŜ3H32), cuya morfología se observa como cristales aciculares

    Efecto de la adición de ácido cítrico y la cantidad de yeso sobre las propiedades del cemento de sulfoaluminato de calcio

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    The influence of citric acid on the hydration and strength development of a calcium sulphoaluminate cement was investigated. Cement pastes were prepared by mixing calcium sulphoaluminate (C4A3Ŝ) with 15, 20 and 25wt% of hemihydrate (CŜH0.5). Citric acid was added as a retarder at 0 and 0.5wt%. The samples were cured at 20 °C for periods of time from 1 to 28 days to evaluate their compressive strength and to characterize the hydration products by scanning electron microscopy and X-ray diffraction. Calorimetric curves showed that the retarding agent considerably decreases the heat release rate and the quantity of total heat released. The main product after the curing was ettringite (C6AŜ3H32). The morphology of this phase consisted of long and thin needles growing radially on the cement grains. Samples with 15wt% of hemihydrate and 0.5wt% of citric acid developed the highest compressive strength (70 MPa) at 28 days of curing.Se investigó el efecto del ácido cítrico sobre la hidratación y propiedades mecánicas de un cemento de sulfoaluminato de calcio. El C4A3Ŝ se mezcló con 15, 20 y 25% e.p. de hemihidrato (CŜH0.5). Se agregó ácido cítrico como retardante en 0 y 0.5% e.p. Las muestras fueron curadas a 20 °C por periodos de 1 a 28 días para realizar mediciones de resistencia a la compresión y caracterizar los productos de hidratación mediante microscopía electrónica de barrido y difracción de rayos X. Las curvas de calorimetría mostraron ue el ácido cítrico disminuye la velocidad de liberación de calor y la cantidad de calor liberado durante la hidratación. La resistencia a la compresión alcanzó un máximo de 70 MPa en muestras con 15% e.p. de hemihidrato y 0,5% e.p de ácido cítrico. Los resultados muestran a la etringita (C6AŜ3H32) como principal producto de hidratación. Se observa a esta fase con morfología acicular creciendo sobre las partículas de cemento

    Differences in resource use lead to coexistence of seed-transmitted microbial populations

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    Seeds are involved in the vertical transmission of microorganisms in plants and act as reservoirs for the plant microbiome. They could serve as carriers of pathogens, making the study of microbial interactions on seeds important in the emergence of plant diseases. We studied the influence of biological disturbances caused by seed transmission of two phytopathogenic agents, Alternaria brassicicola Abra43 (Abra43) and Xanthomonas campestris pv. campestris 8004 (Xcc8004), on the structure and function of radish seed microbial assemblages, as well as the nutritional overlap between Xcc8004 and the seed microbiome, to find seed microbial residents capable of outcompeting this pathogen. According to taxonomic and functional inference performed on metagenomics reads, no shift in structure and function of the seed microbiome was observed following Abra43 and Xcc8004 transmission. This lack of impact derives from a limited overlap in nutritional resources between Xcc8004 and the major bacterial populations of radish seeds. However, two native seed-associated bacterial strains belonging to Stenotrophomonas rhizophila displayed a high overlap with Xcc8004 regarding the use of resources; they might therefore limit its transmission. The strategy we used may serve as a foundation for the selection of seed indigenous bacterial strains that could limit seed transmission of pathogens

    Efficient and versatile data analytics for deep networks

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    Deep networks (DN) perform cognitive tasks related with image and text at human-level. To extract and exploit the knowledge coded within these networks we propose a framework which combines state-of-the-art technology in parallelization, storage and analysis. Our goal, to make DN models available to all data scientists

    MIVES: modelo integrado de valor para evaluaciones de sostenibilidad

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    La valoración y agregación cuantitativa de los distintos requisitos que constituyen los tres pilares básicos de la sostenibilidad es importante para poder comparar de forma objetiva la incidencia relativa de alternativas de materiales o procesos e introducir mejoras. La mayoría de estos requisitos tienen unidades de medida diferentes. Por ello, para valorar el grado de sostenibilidad, es importante basarse en metodologías multicriterio de valoración que permitan valorar y ponderar todos estos requisitos de diferente índole. La metodología multicriterio y programa informático aquí presentado, “MIVES1: Modelo integrado de valor para evaluaciones de sosteniblidad”, permite obtener un único índice de valor que mide el grado de sostenibilidad del material o proceso evaluado. En las primeras fases de la metodología MIVES se realiza un modelo de valoración. En éste, se establecen las condiciones de contorno y los límites del sistema, se estructuran todos los aspectos que serán estudiados, se decide qué funciones de valor se utilizarán para valorar cada uno de los aspectos y por último se determina la importancia de cada uno de ellos. En estas primeras fases es donde realmente se toma la decisión, es decir, se definen los aspectos que serán estudiados y la forma de valorarlos sin estar condicionado por las valoraciones de las alternativas. Posteriormente, se seleccionan y valoran las alternativas. Las aplicaciones de la metodología MIVES son numerosas. Cabe destacar el Anejo 13 de la Instruccuón del hormigón2, que sirve para medir el grado de sostenibilidad de las estructuras de hormigón. La metodología desarrollada representa un avance en términos de valoración, ya que se dota de objetividad y claridad en los procedimientos. A la vez, permite que cualquier persona pueda estudiar la sostenibilidad de otras alternativas a partir del modelo de valoración creado.Postprint (published version

    The alpha-galactosidase A p.Arg118Cys variant does not cause a Fabry disease phenotype: data from individual patients and family studies

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    Acessível em: www.ncbi.nlm.nih.gov/pmc/articles/PMC4423738/Lysosomal α-galactosidase A (α-Gal) is the enzyme deficient in Fabry disease (FD), an X-linked glycosphingolipidosis caused by pathogenic mutations affecting the GLA gene. The early-onset, multi-systemic FD classical phenotype is associated with absent or severe enzyme deficiency, as measured by in vitro assays, but patients with higher levels of residual α-Gal activity may have later-onset, more organ-restricted clinical presentations. A change in the codon 118 of the wild-type α-Gal sequence, replacing basic arginine by a potentially sulfhydryl-binding cysteine residue - GLA p.(Arg118Cys) -, has been recurrently described in large FD screening studies of high-risk patients. Although the Cys118 allele is associated with high residual α-Gal activity in vitro, it has been classified as a pathogenic mutation, mainly on the basis of theoretical arguments about the chemistry of the cysteine residue. However its pathogenicity has never been convincingly demonstrated by pathology criteria. We reviewed the clinical, biochemical and histopathology data obtained from 22 individuals of Portuguese and Spanish ancestry carrying the Cys118 allele, including 3 homozygous females. Cases were identified either on the differential diagnosis of possible FD manifestations and on case-finding studies (n=11; 4 males), or on unbiased cascade screening of probands' close relatives (n=11; 3 males). Overall, those data strongly suggest that the GLA p.(Arg118Cys) variant does not segregate with FD clinical phenotypes in a Mendelian fashion, but might be a modulator of the multifactorial risk of cerebrovascular disease. The Cys118 allelic frequency in healthy Portuguese adults (n=696) has been estimated as 0.001, therefore not qualifying for "rare" condition
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