9,249 research outputs found

    Comment on \u3ci\u3eSmall Bowel Necrosis\u3c/i\u3e

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    Comment on the Article Small bowel necrosis associated with postoperative jejunal tube feeding

    The INTERNODES method for the treatment of non-conforming multipatch geometries in Isogeometric Analysis

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    In this paper we apply the INTERNODES method to solve second order elliptic problems discretized by Isogeometric Analysis methods on non-conforming multiple patches in 2D and 3D geometries. INTERNODES is an interpolation-based method that, on each interface of the configuration, exploits two independent interpolation operators to enforce the continuity of the traces and of the normal derivatives. INTERNODES supports non-conformity on NURBS spaces as well as on geometries. We specify how to set up the interpolation matrices on non-conforming interfaces, how to enforce the continuity of the normal derivatives and we give special attention to implementation aspects. The numerical results show that INTERNODES exhibits optimal convergence rate with respect to the mesh size of the NURBS spaces an that it is robust with respect to jumping coefficients.Comment: Accepted for publication in Computer Methods in Applied Mechanics and Engineerin

    Evolution of Communities with Focus on Stability

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    Community detection is an important tool for analyzing the social graph of mobile phone users. The problem of finding communities in static graphs has been widely studied. However, since mobile social networks evolve over time, static graph algorithms are not sufficient. To be useful in practice (e.g. when used by a telecom analyst), the stability of the partitions becomes critical. We tackle this particular use case in this paper: tracking evolution of communities in dynamic scenarios with focus on stability. We propose two modifications to a widely used static community detection algorithm: we introduce fixed nodes and preferential attachment to pre-existing communities. We then describe experiments to study the stability and quality of the resulting partitions on real-world social networks, represented by monthly call graphs for millions of subscribers.Comment: AST at 42nd JAIIO, September 16-20, 2013, Cordoba, Argentina. arXiv admin note: substantial text overlap with arXiv:1311.550

    Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

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    We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely diluted K+ and Cl− species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl− shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li+Cl−, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.Fil: Semino, Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Zaldivar, Gervasio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Calvo, Ernesto Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Laria, Daniel Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Comisión Nacional de Energía Atómica; Argentin

    Revisión de normas nacionales e internacionales de cementos

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    En este trabajo se realiza una revisión de normas correspondientes a cementos, con base en clinker de cemento portland, dicha revisión es motivada por el cambio en la especificación de cementos de la norma IRAM. Se analizan las nuevas normas IRAM y se las compara con ASTM y UNE. El objetivo de la revisión es identificar las diferentes adiciones que utilizan las diferentes normativas y los porcentajes de reemplazo de clinker de cemento Pórtland que las mismas permiten. Del mismo modo se comparan los requisitos físicos, químicos y mecánicos que cada norma impone.Trabajo realizado por becario del LEMIT. Director: Dr. R. Zerbin

    Total Nutrient Admixtures (3-in-1): Pros vs Cons for Adults

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    Total nutrient admixture (TNA) is a complete parenteral nutrition (PN) formulation composed of all macronutrients, including dextrose, amino acids, and intravenous fat emulsions (IVFE), in one bag. The TNA may be safely administered to the patient, with all components aseptically compounded and minimal administration manipulation required, lending itself to decreases in risks of catheter contamination and patient infections. The TNA is compatible and stable at recommended concentrations, and since the IVFE is in the TNA, it is infused at slower rates, allowing for better fat clearance. The TNA offers convenience of administration and a potential cost savings to the healthcare institution both directly and indirectly. Unfortunately, the TNA is not without concerns. At low macronutrient concentrations (lower than recommended), the formulation is compromised. Greater divalent and monovalent cation amounts and increased concentrations of phosphate and calcium may destabilize the TNA or result in precipitation, respectively. With the addition of IVFE in the TNA, catheter occlusion is greater and larger pore size filters are necessary, resulting in less microbial elimination. Determining if the implementation of the TNA is appropriate for an institution requires a recognition of the advantages and disadvantages of the TNA as well as an understanding of the institution’s patient population and their nutrition requirements

    Analytic Design Techniques for MPT Antenna Arrays

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    Solar Power Satellites (SPS) represent one of the most interesting technological opportunities to provide large scale, environmentally clean and renewable energy to the Earth [1]‐[3]. A fundamental and critical component of SPSs is the Microwave Power Transmission (MPT) system, which is responsible for the delivery of the collected solar power to the ground rectenna [2]. Towards this end, the MPT array must exhibit a narrow main beam width (), a high beam efficiency (BWBE), and a low peak sidelobe level (). Moreover, reduced realization costs and weights are also necessary [3]. To reach these contrasting goals, several design techniques have been investigated including random methods [4] and hybrid deterministic‐random approaches [2][3]. On the contrary, well‐established design tools based on stochastic optimizers [5][6] are difficult to be employed, due to their high computational costs when dealing with large arrays as those of interest in SPS [3]
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