Two Decreasing Measures for Simply Typed ?-Terms

This paper defines two decreasing measures for terms of the simply typed ?-calculus, called the ?-measure and the ?^{?}-measure. A decreasing measure is a function that maps each typable ?-term to an element of a well-founded ordering, in such a way that contracting any ?-redex decreases the value of the function, entailing strong normalization. Both measures are defined constructively, relying on an auxiliary calculus, a non-erasing variant of the ?-calculus. In this system, dubbed the ?^{?}-calculus, each ?-step creates a "wrapper" containing a copy of the argument that cannot be erased and cannot interact with the context in any other way. Both measures rely crucially on the observation, known to Turing and Prawitz, that contracting a redex cannot create redexes of higher degree, where the degree of a redex is defined as the height of the type of its ?-abstraction. The ?-measure maps each ?-term to a natural number, and it is obtained by evaluating the term in the ?^{?}-calculus and counting the number of remaining wrappers. The ?^{?}-measure maps each ?-term to a structure of nested multisets, where the nesting depth is proportional to the maximum redex degree

Alternativas de manejo autosustentable, para un viñedo en Colonia Caroya

Trabajo final integrador. (Area de Consolidación Sistemas Agrícolas de Producción Intensivos)--UNC- Facultad de Ciencias Agropecuarias, 2016.La producción intensiva de manera sustentable está cobrando cada vez más importancia, esto se debe a diferentes razones; en primer lugar, la gran dependencia de los insumos externos, que encarecen los costos productivos, traen aparejado problemas ambientales, e inciden negativamente en el organismo humano y en el propio sistema agrícola. El interés en la realización de este trabajo es presentar alternativas de manejo diferentes al convencional, en un viñedo de la región de Colonia Caroya, Provincia de Córdoba, para lograr un producto de alta calidad y de manera sustentable. Objetivo general: Mejorar las condiciones edáficas y sanitarias del viñedo mediante la adopción de prácticas que permitan mantener la sustentabilidad del sistema. Objetivos específicos: - Plantear como alternativas de manejo, la implantación de un cultivo de cobertura y la elaboración de un compost para mejorar la condición física del suelo y disponibilidad de nutrientes para las cepas. - Proponer el armado del compost como opción para reducir las fuentes de inóculo de patógenos y las formas invernantes de plagas que sobreviven en restos de poda, racimos sin cosechar y hojas. - Determinar los costos de las propuestas de manejo planteadas

Molecular Dynamics Simulations of Substrate Release from Trypanosoma cruzi UDP-Galactopyranose Mutase

The enzyme UDP-galactopyranose mutase (UGM) represents a promising drug target for the treatment of infections with Trypanosoma cruzi. We have computed the Potential of Mean Force for the release of UDP-galactopyranose from UGM, using Umbrella Sampling simulations. The simulations revealed the conformational changes that both substrate and enzyme undergo during the process. It was determined that the galactopyranose portion of the substrate is highly mobile and that the opening/closing of the active site occurs in stages. Previously uncharacterized interactions with highly conserved residues were also identified. These findings provide new pieces of information that contribute to the rational design of drugs against T. cruzi.Fil: Cossio Pérez, Rodrigo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pierdominici Sottile, Gustavo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sobrado, Pablo. No especifíca;Fil: Palma, Juliana Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentin

Symmetry groups, semidefinite programs, and sums of squares

We investigate the representation of symmetric polynomials as a sum of squares. Since this task is solved using semidefinite programming tools we explore the geometric, algebraic, and computational implications of the presence of discrete symmetries in semidefinite programs. It is shown that symmetry exploitation allows a significant reduction in both matrix size and number of decision variables. This result is applied to semidefinite programs arising from the computation of sum of squares decompositions for multivariate polynomials. The results, reinterpreted from an invariant-theoretic viewpoint, provide a novel representation of a class of nonnegative symmetric polynomials. The main theorem states that an invariant sum of squares polynomial is a sum of inner products of pairs of matrices, whose entries are invariant polynomials. In these pairs, one of the matrices is computed based on the real irreducible representations of the group, and the other is a sum of squares matrix. The reduction techniques enable the numerical solution of large-scale instances, otherwise computationally infeasible to solve.Comment: 38 pages, submitte

Hacia un sistema I polimórfico

Sistema I es un lambda cálculo simplemente tipado con pares, extendido con una teoría ecuacional obtenida a partir de los isomorfismos de tipos existentes entre los tipos simples con pares. En este trabajo en progreso proponemos una extensión de Sistema I hacia tipos polimórficos, añadiendo al sistema de tipos tanto el cuantificador universal como sus isomorfismos relacionados.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

Hacia un sistema I polimórfico

Sistema I es un lambda cálculo simplemente tipado con pares, extendido con una teoría ecuacional obtenida a partir de los isomorfismos de tipos existentes entre los tipos simples con pares. En este trabajo en progreso proponemos una extensión de Sistema I hacia tipos polimórficos, añadiendo al sistema de tipos tanto el cuantificador universal como sus isomorfismos relacionados.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

Effects of hemorrhage on gastrointestinal oxygenation

Objectives: (1) To demonstrate that metabolic parameters are better indicators of tissue hypoxia than regional and whole oxygen consumption (VO2). (2) To compare intramucosal pH (pHi) in different gastrointestinal segments. Design: Prospective, interventional study. Setting: Research laboratory at a university center. Subjects: Fourteen anesthetized, mechanically ventilated dogs. Interventions: Twenty milliliters per kilogram bleeding. Measurements and main results: We placed pulmonary, aortic and mesenteric venous catheters, and an electromagnetic flow probe in the superior mesenteric artery, and gastric, jejunal and ileal tonometers to measure flows, arterial and venous blood gases and lactate, and intramucosal PCO2. We calculated systemic and intestinal oxygen transport (DO2) and consumption (VO2), pHi and arterial minus intramucosal PCO2 (ΔPCO2). Then, we bled the dogs and repeated the measurements after 30 min. Systemic and intestinal DO2 fell (26.0±7.3 versus 8.9±2.6 and 71.9±17.3 versus 24.6±9.6 ml/min per kg, respectively, p<0.0001). Systemic and intestinal VO2 remained unchanged (5.5±1.3 versus 5.4±1.3 and 15.7±5.0 versus 14.9±5.3 ml/min per kg, respectively). Gastric, jejunal and ileal pHi (7.13±0.11 versus 6.96±0.17, 7.18±0.06 versus 6.97±0.15, 7.12±0.11 versus 6.94±0.14, p<0.05) and ΔPCO2 (21±13 versus 35±23, 15±5 versus 33±16, 23±17 versus 38±20, p<0.05) changed accordingly. Arterial and mesenteric venous lactate and their difference, rose significantly (1.7±0.9 versus 3.7±1.4 and 1.8±0.8 versus 4.3±1.5 mmol/l, 0.1±0.6 versus 0.6±0.7 mmol/l, p<0.05). Conclusions: During hemorrhage, systemic and intestinal VO2 remained stable. However, hyperlactatemia and intramucosal acidosis evidenced anaerobic metabolism. pHi changes paralleled in the three intestinal segments.Facultad de Ciencias Médica

Effects of levosimendan and dobutamine in experimental acute endotoxemia : A preliminary controlled study

Objective: To test the hypothesis that levosimendan increases systemic and intestinal oxygen delivery (DO2) and prevents intramucosal acidosis in septic shock. Design: Prospective, controlled experimental study. Setting: University-based research laboratory. Subjects: Nineteen anesthetized, mechanically ventilated sheep. Interventions: Endotoxin-treated sheep were randomly assigned to three groups: control (n = 7), dobutamine (10 μg/kg/min, n = 6) and levosimendan (100 μg/kg over 10 min followed by 100 μg/kg/h, n = 6) and treated for 120 min. Measurements and main results: After endotoxin administration, systemic and intestinal DO 2 decreased (24.6 ± 5.2 vs 15.3 ± 3.4 ml/kg/min and 105.0 ± 28.1 vs 55.8 ± 25.9 ml/kg/min, respectively; p < 0.05 for both). Arterial lactate and the intramucosal–arterial PCO2 difference (∆PCO2) increased (1.4 ± 0.3 vs 3.1 ± 1.5 mmHg and 9 ± 6 vs 23 ± 6 mmHg mmol/l, respectively; p < 0.05). Systemic DO 2 was preserved in the dobutamine-treated group (22.3 ± 4.7 vs 26.8 ± 7.0 ml/min/kg, p = NS) but intestinal DO 2 decreased (98.9 ± 0.2 vs 68.0 ± 22.9 ml/min/kg, p < 0.05) and ∆PCO 2 increased (12 ± 5 vs 25 ± 11 mmHg, p < 0.05). The administration of levosimendan prevented declines in systemic and intestinal DO 2 (25.1 ± 3.0 vs 24.0 ± 6.3 ml/min/kg and 111.1 ± 18.0 vs 98.2 ± 23.1 ml/min/kg, p = NS for both) or increases in ∆PCO2 (7 ± 7 vs 10 ± 8, p = NS). Arterial lactate increased in both the dobutamine and levosimendan groups (1.6 ± 0.3 vs 2.5 ± 0.7 and 1.4 ± 0.4 vs. 2.9 ± 1.1 mmol/l, p = NS between groups). Conclusions: Compared with dobutamine, levosimendan increased intestinal blood flow and diminished intramucosal acidosis in this experimental model of sepsis.Facultad de Ciencias Médica

Increased blood flow prevents intramucosal acidosis in sheep endotoxemia: a controlled study

Introduction Increased intramucosal–arterial carbon dioxide tension (PCO₂) difference (∆PCO₂) is common in experimental endotoxemia. However, its meaning remains controversial because it has been ascribed to hypoperfusion of intestinal villi or to cytopathic hypoxia. Our hypothesis was that increased blood flow could prevent the increase in ∆PCO₂. Methods In 19 anesthetized and mechanically ventilated sheep, we measured cardiac output, superior mesenteric blood flow, lactate, gases, hemoglobin and oxygen saturations in arterial, mixed venous and mesenteric venous blood, and ileal intramucosal PCO₂ by saline tonometry. Intestinal oxygen transport and consumption were calculated. After basal measurements, sheep were assigned to the following groups, for 120 min: (1) sham (n = 6), (2) normal blood flow (n = 7) and (3) increased blood flow (n = 6). Escherichia coli lipopolysaccharide (5 µg/kg) was injected in the last two groups. Saline solution was used to maintain blood flood at basal levels in the sham and normal blood flow groups, or to increase it to about 50% of basal in the increased blood flow group. Results In the normal blood flow group, systemic and intestinal oxygen transport and consumption were preserved, but ∆PCO₂ increased (basal versus 120 min endotoxemia, 7 ± 4 versus 19 ± 4 mmHg; P < 0.001) and metabolic acidosis with a high anion gap ensued (arterial pH 7.39 versus 7.35; anion gap 15 ± 3 versus 18 ± 2 mmol/l; P < 0.001 for both). Increased blood flow prevented the elevation in ∆PCO2 (5 ± 7 versus 9 ± 6 mmHg; P = not significant). However, anion-gap metabolic acidosis was deeper (7.42 versus 7.25; 16 ± 3 versus 22 ± 3 mmol/l; P < 0.001 for both). Conclusions In this model of endotoxemia, intramucosal acidosis was corrected by increased blood flow and so might follow tissue hypoperfusion. In contrast, anion-gap metabolic acidosis was left uncorrected and even worsened with aggressive volume expansion. These results point to different mechanisms generating both alterations.Facultad de Ciencias Médica