4,849 research outputs found

    Differential structure of the Thompson components of selfadjoint operators

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    Different equivalence relations are defined in the set L(H)s of self- adjoint operators of a Hilbert space H in order to extend a very well known relation in the cone of positive operators. As in the positive case, for a G L(H)s the equivalence class Ca admits a differential structure, which is compatible with a complete metric defined on Ca. This metric coincides with the Thompson metric when a is positive.Fil: Fongi, Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Maestripieri, Alejandra Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

    On complementable operators in the sense of T. Ando

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    Consider an operator A :H→K between Hilbert spaces and closed subspaces S ⊂ H and T ⊂ K. If there exist projections E on H and F on K such that R(E) =S, R(F) =T and AE=F∗A then A is called (S, T)-complementable. The origin of this notion comes from the idea of T. Ando of defining Schur complements in terms of operators. In this paper we present some characterizations of these triples (A, S, T) and applications to bilateral Schur complements and generalized Wiener-Hopf operators.Fil: Arias, Maria Laura. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Corach, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Maestripieri, Alejandra Laura. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

    Schur complements in Krein spaces

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    The aim of this work is to generalize the notions of Schur complements and shorted operators to Krein spaces. Given a (bounded) J-selfadjoint operator A (with the unique factorization property) acting on a Krein space H and a suitable closed subspace S of H, the Schur complement A/[s]of A to S is defined. The basic properties of A/ are developed and different characterizations are given, most of them resembling those of the shorted of (bounded) positive operators on a Hilbert space.Fil: Maestripieri, Alejandra Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Matemáticas; ArgentinaFil: Martinez Peria, Francisco Dardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

    Range additivity, shorted operator and the Sherman-Morrison-Woodbury formula

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    We say that two operators A, B have the range additivity property if R(A + B) = R(A) + R(B). In this article we study the relationship between range additivity, shorted operator and certain Hilbert space decomposition known as compatibility. As an application, we extend to infinite dimensional Hilbert space operators a formula by Fill and Fishkind related to the well-known Sherman-Morrison-Woodbury formula

    Depth sensing indentation of organic-inorganic hybrid coatings deposited onto a polymeric substrate

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    PEO-Si/SiO2 hybrid coatings deposited onto a PVC substrate were micromechanically characterized using depth sensing indentation. The effect of curing time and coating thickness was investigated. Elastic moduli of coated systems determined by the Oliver–Pharr approach displayed a continuous decreasing trend with increasing indentation depth, reflecting that the hybrids are stiffer than the substrate. Aiming to extract coating-only elastic modulus a simple method based on FE simulations was developed. The method was applied to evaluate the moduli of the hybrid coatings and the values were compared with those obtained by applying different approaches available in literature. The elastic modulus of PEO-Si/SiO2 hybrids was proven to be practically independent of curing time after 24 h. However, large curing times resulted in coatings being more prone to failure.Fil: Fasce, Laura Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Seltzer, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Frontini, Patricia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

    Sard's approximation processes and oblique projections

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    Three problems arising in approximation theory are studied. These problems have already been studied by Arthur Sard. The main goal of this paper is to use geometrical compatibility theory to extend Sard's results and get characterizations of the sets of solutions.Fil: Corach, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Giribet, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Maestripieri, Alejandra Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

    Pharmacokinetics of Cephalexin after Intravenous and Single and Multiple Intramuscular Administration to Rabbit

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    Cephalexin is a first generation cephalosporin widely used in rabbits. Its spectrum includes Pasteurella multocida and Staphylococcus aureus. These bacteria, together with Bordetella bronchiseptica, are the main cause of respiratory infections. Although many textbooks on rabbit therapeutics report the use of cephalexin, including administration schedules, there are not published papers on the pharmacokinetics of cephalexin after IV and IM administration to rabbit. Therefore, the objective of the present study was to describe cephalexin disposition in rabbits after intravenous and single and multiple intramuscular administrations. Three administration schedules were studied: single IV administration (10 mg/kg), single IM administration (10 mg/kg) and multiple IM administration (2.5 mg/kg/6). Serial blood samples were collected over a 24 h period. Cephalexin plasma concentrations were determined by microbiological method using Kocuria rhizophila ATCC 9341 as microorganism test. No statistical differences were observed between routes of administration for any of the estimated PK parameters. The unique difference was observed on bioavailability between intramuscular administration schedules. Elimination half-life was 1.45, 1.09 and 1.91 h for the single IV, single IM and multiple IM administration, respectively. Bioavailability after single and multiple IM administration was 47 and 97.5%, respectively. After multiple IM administration maximum and minimum plasma concentration at steady state were 2.77 and 0.34 µg/ml, while Cmax after single IM administration was 9. 22 µg/ml. Considering that for betalactams the PK/PD breakpoint recommended for efficacy (T > MIC) should be 50–80% and that the reported MIC for most gram-positive organisms and Pasteurella multocida is ≤1.0 μg/ml, the present study demonstrates that a single IM dose of 10 mg/kg/24 h is enough to maintain therapeutic concentrations for a 24 hours period. When a 2.5mg/kg dose is used administration every 6 hours is recommended.Fil: Meneses, María Laura. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Albarellos, Gabriela Alejandra. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Landoni, Maria Fabiana. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    The local print media: A challenge to the top-down and homogenizing trends during Peronism

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    En los estudios de historia argentina contemporánea, en las últimas décadas han proliferado estudios sobre el papel fundamental de los periódicos de diferente alcance en la definición de identidades y prácticas políticas, especialmente aquellos anclados en las grandes ciudades. Menos examinados han sido los medios impresos de los pueblos del interior, aunque han ejercido notable influencia en la vida político-social, privilegiando la información lugareña mezclada con opinión y oficiando como fuente de legitimidad ideológica de la elite, espacio de sociabilidad y canal de mediación entre los vecinos y la Municipalidad. A la luz de lo expuesto, analizaremos el rol político de la prensa local "extracéntrica" durante la etapa peronista (1946-1955), en base a la premisa de que el ámbito local constituye una unidad de análisis capaz de ayudarnos a comprender los procesos de construcción de poder en democracia. En un contexto caracterizado por signos de verticalismo y unanimismo oficialista, ésta -a pesar de las limitaciones- habría resguardado cierta autonomía de lo local de las tendencias hegemónicas.In studies of contemporary history Argentina, in recent decades they have proliferated studies on the fundamental role of newspapers of different scope in defining identities and political practices, especially those anchored in large cities. Less examined are the print media in the inland villages, although they have exercised significant influence over the political and social life, favoring the villager information mixed with opinion and officiating as a source of ideological legitimacy of elite, space of sociability and mediation between residents and the Municipality. In light of the above, we discuss the political role of the "extracéntrica" local press during the Peronist era (1946-1955), based on the premise that the local level is a unit of analysis can help us understand the processes construction of power in democracy. In a context characterized by signs of verticality and unanimity ruling, this, despite the limitations, would have protected some autonomy from the local hegemonic tendencies.Fil: Salomón, Alejandra Laura. Universidad Nacional de Quilmes. Departamento de Ciencias Sociales. Centro de Estudios de la Argentina Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Análisis de algunos diseños curriculares actuales desde la perspectiva de género

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    Fil: Barba, Laura Alejandra. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina

    Stability Studies of the Vaccine Adjuvant U-Omp19

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    Unlipidated outer membrane protein 19 (U-Omp19) is a novel mucosal adjuvant in preclinical development to be used in vaccine formulations. U-Omp19 holds two main properties, it is capable of inhibiting gastrointestinal and lysosomal peptidases, increasing the amount of co-administered antigen that reaches the immune inductive sites and its half-life inside cells, and it is able to stimulate antigen presenting cells in vivo. These activities enable U-Omp19 to enhance the adaptive immune response to co-administrated antigens. To characterize the stability of U-Omp19 we have performed an extensive analysis of its physicochemical and biological properties in a 3-year long-term stability study, and under potentially damaging freeze-thawing and lyophilization stress processes. Results revealed that U-Omp19 retains its full protease inhibitor activity, its monomeric state and its secondary structure even when stored in solution for 36 months or after multiple freeze-thawing cycles. Non-enzymatic hydrolysis resulted the major degradation pathway for storage in solution at 4 °C or room temperature which can be abrogated by lyophilization yet increasing protein tendency to form aggregates. This information will play a key role in the development of a stable formulation of U-Omp19, allowing an extended shelf-life during manufacturing, storage, and shipping of a future vaccine containing this pioneering adjuvant.Fil: Darriba, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Cerutti, Maria Laura. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Bruno, Laura Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Cassataro, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Pasquevich, Karina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin
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