282 research outputs found

    Using an ensemble of features for personalized recommendations of scientific publications

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    Maintaining reviews of scientific publications as soon as new relevant publications are available is a typical challenge to many research communities. We address this challenge as a content-based recommendation problem, where the publications already selected for a review drive the recommendation of the new publications. In addition, resources such as domain databases, ontologies and academic graphs provide structured information about publications (e.g., authors, journals, conferences). Our experiments show that a simple model based on that structured information to represent publications achieve high precision and recall, and outperform models that use more sophisticated representations based on embeddings

    Assessment of the splitting-tensile strength of ZP-306 steel fiber reinforced concrete

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    El concreto reforzado con fibras de acero (CRFA) es un material con gran potencial de uso en viviendas de concreto de baja altura, ya que la capacidad de resistencia de los muros está controlada por la resistencia a tensión diagonal. El artículo presenta los resultados de un estudio experimental para caracterizar la resistencia a tensión por compresión diametral del CRFA que es elaborado con fibra ZP-306 y con concretos locales. El programa experimental incluyó el ensayo de 52 especímenes en forma de cilindros. En el estudio se discuten los modelos de predicción disponibles y se realiza un análisis estadístico para comparar los resultados calculados con los datos medidos. Con base en las tendencias de los resultados experimentales, se proponen ecuaciones para estimar los parámetros que describen la envolvente del comportamiento esfuerzo-deformación del CRFA sometido a esfuerzos de compresión diametral. Las ecuaciones se han desarrollado en un formato versátil para ser incluidas en un reglamento de diseño. Abstract Steel fibers reinforced concrete (SFRC) is a material with great potential to be used in low-rise concrete housing because the strength capacity of the walls is controlled by diagonal tension strength. The paper shows the results of an experimental study intended to characterize splitting-tensile strength of SFRC made of both ZP-306 fiber and local concrete. The experimental program included the tests of 52 cylindrical-shaped specimens. The study discusses the available predictive models and shows a statistical analysis to compare the predicted results with measured data. Based on trends of the experimental results, equations to estimate the parameters describing the backbone of the stress-strain behavior of SFRC under splitting-tensile strength are proposed. The equations have been developed in a versatile format to be included in a design code

    Laboratório de citogenética vegetal Embrapa Recursos Genéticos e Biotecnologia: normas de utilização e manutenção.

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    O Laboratório de Citogenética Vegetal foi criado com o intuito de realizar pesquisas básicas de caracterização de recursos genéticos vegetais, que auxiliam direta ou indiretamente a coleta, multiplicação, conservação e consequentemente disponibiliza dados ao melhorista que poderá fazer uso imediato ou futuro deste recurso. Os estudos incluem: análise do número e morfologia de cromossomos; análise do comportamento meiótico; estudos de poliploidia; estudos de comportamento e estabilidade cromossômica; análise da viabilidade de pólen; identificação de apomixia; identificação de casmo/cleistogamia; estudos de hibridação intra/interespecífica e intergenérica; identificação de auto/alogamia; desenvolvimento e adaptação de metodologias para análise citogenética e reprodutiva em germoplasma vegetal. Além disso, o laboratório oferece sua infraestrutura está para o treinamento de recursos humanos em caracterização citogenética, através de estágios e cursos que são oferecidos conforme a demanda

    The small rna ryhb homologs from salmonella typhimurium restrain the intracellular growth and modulate the spi-1 gene expression within raw264.7 macrophages

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    Indexación ScopusGrowing evidence indicates that small noncoding RNAs (sRNAs) play important regulatory roles during bacterial infection. In Salmonella Typhimurium, several sRNAs are strongly up-regulated within macrophages, but little is known about their role during the infection process. Among these sRNAs, the well-characterized paralogs RyhB-1 and RyhB-2 are two regulators of gene expression mainly related with the response to iron availability. To investigate the role of the sRNAs RyhB-1 and RyhB-2 from S. Typhimurium in the infection of RAW264.7 macrophages, we analyzed several phenotypic traits from intracellular mutant strains lacking one and both sRNAs. Deletion of RyhB-1 and/or RyhB-2 resulted in increased intracellular survival and faster replication within macrophages. The bacterial metabolic status inside macrophages was also analyzed, reveal-ing that all the mutant strains exhibited higher intracellular levels of ATP and lower NAD+/NADH ratios than the wild type. Expression analyses from bacteria infecting macrophages showed that RyhB-1 and RyhB-2 affect the intra-macrophage expression of bacterial genes associated with the Salmonella pathogenicity island 1 (SPI-1) and the type III secretion system (T3SS). With a two-plas-mid system and compensatory mutations, we confirmed that RyhB-1 and RyhB-2 directly interact with the mRNAs of the invasion chaperone SicA and the regulatory protein RtsB. Altogether, these results indicate that the RyhB homologs contribute to the S. Typhimurium virulence modulation inside macrophages by reducing the intracellular growth and down-regulating the SPI-1 gene ex-pression. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.https://www.mdpi.com/2076-2607/9/3/63

    Caso único: el efecto Ringelmann en un bote de remo de elite = Unique case: The Ringelmann effect on a rowboat elite

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    Objetivo: Analizar si en la tripulación del cuatro sin timonel español seleccionada para el preolímpico de Río de Janeiro 2016 presenta el efecto Ringelmann, consistente en que conforme aumenta el número de componentes de un grupo, la aportación individual, al resultado final, va disminuyendo. Método: La muestra la componen los cuatro remeros de la tripulación del citado bote con una experiencia de 13, 16, 10 y 13 años respectivamente, y una edad media de 24.25 ± 0.5 años. Resultados: En la totalidad de los casos se produce un aumento sistemático en la condición del equipo respecto de la individual, con una media de metros recorridos en esta de 1029.25 metros, mientras que en la grupal fue de 1036.75. El número de vatios generados también fue superior en la ejecución colectiva (535.25w. frente a los 524.25w.). Sin embargo, la media de paladas en la condición individual fue inferior (35.5) a la de grupo (37.25). En cuanto a la percepción de esfuerzo (escala de Borg), los remeros puntuaban más bajo individualmente (7.75) que en grupo (8.75). Conclusiones: Nuestros datos parecen mostrar que el nivel competitivo, la fuerte convicción de equipo y la alta motivación pueden no solo paliar, sino hacer desaparecer el efecto Ringelmann en un bote de cuatro sin timonel. A pesar de que la percepción de esfuerzo es mayor en equipo. ABSTRACT Objective: Try to know if the crew of the Spanish boat Coxless four selected for the pre-Olympic 2016 Rio de Janeiro shows the Ringelmann effect, which is that as the number of components of a group, the individual contribution decreases. Method: The sample is composed of four rowers crew of that boat with an experience of 13, 16, 10 and 13 years, respectively, and an average age of 24.25 years ([DT] = 0.5). Results: In all cases a systematic increase occurs in the equipment condition regarding individual, with an average of meters traveled in this of 1029.25 meters, while the group was 1036.75. The number of watts generated was also higher in the collective execution (535.25w. versus 524.25w.). However, the average of strokes in the individual condition was lower (35.5) to the group (37.25). As for the perception of effort (Borg scale), the rowers individually scored lower (7.75) than in group (8.75)
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