Fresnel coefficients as hyperbolic rotations

We describe the action of a plane interface between two semi-infinite media in terms of a transfer matrix. We find a remarkably simple factorization of this matrix, which enables us to express the Fresnel coefficients as a hyperbolic rotation.Comment: 6 pages, 3 figure

Distribución real y potencial del género hiperparasitoide Mesochorus Gravenhorst (Ichneumonidae: Mesochorinae) en Brasil

Mesochorus species are hyperparasitoids capable of nullifying biological control agents. This study is the first to map and predict the distribution of this genus in Brazil. Species distribution modeling was used to estimate the potential distribution of Mesochorus. We obtained 72 occurrence records of 49 Mesochorus species, being 30 endemics. According to our prediction model, this genus can be distributed in all Brazilian biomes, with higher suitability of occurrence in the Atlantic Forest and lower in the Caatinga and Pampa.Las especies de Mesochorus son hiperparasitoides capaces de anular los agentes de control biológico. Este estudio es el primero en mapear y predecir la distribución de este género en Brasil. Se utilizó un modelo de distribución de especies para estimar la distribución potencial de Mesochorus. Obtuvimos 72 registros de ocurrencia de 49 especies de Mesochorus, siendo 30 endémicas. De acuerdo con nuestro modelo de predicción, este género se puede distribuir en todos los biomas brasileños, con una mayor idoneidad de ocurrencia en el Bosque Atlántico y menor en la Caatinga y Pampa

Synthesis of graphenic nanomaterials by decomposition of methane on a Ni-Cu/biomorphic carbon catalyst. Kinetic and characterization results

This work addresses the preparation and application of the synthesis of graphene in Ni-Cu catalysts supported on carbonaceous materials. The catalysts have been prepared by a biomorphic mineralization technique which involves the thermal decomposition, under reductive atmosphere, of commercial cellulose previously impregnated with the metallic precursors. The characterization results indicate that the preparation method leads to the formation of carbonaceous supports with a moderate microporosity (ca. 33% pore volume) and adequate surface area (343 m2/g), maintaining the original external texture. The catalytic performance of these materials was previously tested in liquid phase reactions (Zampieri et al., 2007 [7]). In order to extend the use of these catalysts, in this work we present a study corresponding to a gas phase reaction: the synthesis of graphenic nanomaterials by catalytic decomposition of methane (CDM). The influence of the reaction temperature and of the feed composition (i.e.%CH4 and%H2) has been studied. The graphenic nanomaterials obtained after reaction were characterized by nitrogen adsorption-desorption isotherms, Raman spectroscopy and transmission electron microscopy (TEM). The results indicate that the carbonaceous nanomaterial with the highest quality is obtained operating at 950 °C and feeding 28.6% of CH4 and 14.3% of H2. The evolution of the carbon mass during the reaction time was analysed using a phenomenological kinetic model that takes into account the main stages involved during the formation of carbonaceous nanomaterials (NCMs). The results obtained from the kinetic model along with the characterization results enable the influence of the operating variables on each stage of the carbonaceous nanomaterial formation to be discerned

Pulmonary but not subcutaneous vaccination confers protection to TB susceptible mice by an IL17-dependent mechanism.

Some of the most promising novel tuberculosis vaccine strategies currently under development are based on respiratory vaccination, mimicking the natural route of infection. In this work, we have compared pulmonary and subcutaneous delivery of BCG vaccine in the tuberculosis-susceptible DBA/2 mouse strain, a model in which parenterally administered BCG vaccine does not protect against tuberculosis. Our data show that intranasally but not subcutaneously administered BCG confers robust protection against pulmonary tuberculosis challenge. In addition, our results indicate that pulmonary vaccination triggers a Mycobacterium tuberculosis–specific mucosal immune response orchestrated by interleukin 17A (IL-17A). Thus, IL-17A neutralization in vivo reduces protection and abrogates M. tuberculosis–specific immunoglobulin A (IgA) secretion to respiratory airways and lung expression of polymeric immunoglobulin receptor induced following intranasal vaccination. Together, our results demonstrate that pulmonary delivery of BCG can overcome the lack of protection observed when BCG is given parenterally, suggesting that respiratory tuberculosis vaccines could have an advantage in tuberculosis-endemic countries, where intradermally administered BCG has inefficient effectiveness against pulmonary tuberculosis

Growth of carbonaceous nanomaterials over stainless steel foams. Effect of activation temperature

Some of the problems that occur during the operation of chemical reactors based of structured catalytic substrates, as monoliths, foams, membranes, cloths, fibres and other systems, are related to the preparation of long term stable coatings. Frequently, the deposition of the catalytic layer is carried out by washcoating, requiring this step a cautious attention, especially in the case of complex geometries, like of that of foams or cloths. In the case of the deposition of layers of carbonaceous materials (CNMs), an alternative route, avoiding the washcoating, it is their direct growth by catalytic decomposition light hydrocarbons (also called CCVD), over the surface of the metallic substrate. In this case, if the metallic substrate is of stainless steel, it already contains the catalytic active phases like Fe and Ni. In order to optimize the process of CNMs growth over structured metallic substrates, we are studying the effect of the main operational variables of the ethane decomposition reaction on stainless steel foams. In this contribution we present a study of the influence of the temperature of the activation (oxidation and reduction) stage on the type and morphology of the carbonaceous materials formed. The results obtained allow us to determine the optimal operating conditions to maximize the amount and the selectivity of the process to obtain a given type of CNM

Performance of AISI 316L-stainless steel foams towards the formation of graphene related nanomaterials by catalytic decomposition of methane at high temperature

This work explores the preparation of graphene-related materials (GRMs) grown on stainless steel foams via catalytic decomposition of methane (CDM). The main active phases for the reaction are the Fe nanoparticles segregated from the stainless-steel after the activation stage of the foam. The effect of the feed composition and reaction temperature has been studied in order to maximize the productivity, stability and selectivity to GRMs. The maximum productivity attained was 0.116 gC/gfoam h operating at 950 °C with a feed ratio of CH4/H2 = 3 (42.9 %CH4:14.3 %H2). The carbonaceous nanomaterials (CNMs) obtained were characterized by X-Ray diffraction, Raman spectroscopy and by transmission and scanning electron microscopy. The parameters of the kinetic model developed are directly related to the relevant stages of the process, including carburization, diffusion-precipitation and deactivation-regeneration. The balance among these sequential stages determines the overall performance of the activated foam. In conditions of rapid carburization of the Fe NPs (pCH4 > 14 %), the productivity to CNMs is favoured, avoiding an initial deactivation of the active sites by fouling with amorphous carbon. After a rapid carburization, the selectivity to the different CNMs is governed by the ratio CH4/H2, and mainly by the temperature. Thus, the formation of GRMs, mainly Few Layer Graphene (FLG) and even graphene, is favoured at temperatures above 900 °C. At lower temperatures, carbon nanotubes are formed

Urolitiasis en caprinos del Departamento Empedrado (Corrientes, Argentina)

Obstructive urolithiasis is a disease caused by total or partial obstruction of the urinary system, and it is very common in small ruminants under intensive production. In a group of 58 confined goats, 8 of them had this disease, and 6 castrated males, died. Sick animals showed decay, apathy, and anorexia. Afterwards, some animals revealed hunched loin, distended abdomen sensitive to palpation, negative apnea test, superficial and accelerated breathing, as well as interrupted bleat. Urethral sondages, blood testing and necropsies were done to the dead animals, and the corresponding samples were sent to the lab and histopathology analysis. Results revealed obstructive disease, which derived in diet reformulation for disease control, with no further new cases.La urolitiasis es un trastorno obstructivo total o parcial de las vías urinarias, frecuente en pequeños rumiantes en producción intensiva. En una población de 58 caprinos confinados, se detectaron 8 casos de urolitiasis, de los cuales murieron 6 animales afectados (machos castrados). Los caprinos enfermos manifestaron decaimiento, apatía y anorexia. Posteriormente hubo animales que presentaron postura antiálgica (lomo encorvado), abdomen distendido y muy sensible a la palpación, prueba de apnea negativa, respiración superficial y acelerada, así como también balido interrumpido. Se realizaron sondajes uretrales, extracciones de sangre y necropsias a los animales muertos, efectuando las correspondientes tomas de muestras para análisis histopatológicos y de laboratorio. Los resultados obtenidos revelaron la existencia de trastornos obstructivos, lo cual derivó en la reformulación de la dieta de los caprinos y generó el control de la enfermedad, sin posterior aparición de nuevos casos

Colocações especializadas na ciência da computação: uma proposta de estudo terminológico para fins de ensino de inglês

O objetivo deste trabalho é propor um estudo descritivo das colocações de cunho terminológico em artigos científicos em inglês no campo da Ciência da Computação. Assim, a razão do desenvolvimento deste projeto ocorre pela necessidade de estudantes e professores não nativos de reconhecer as convencionalidades léxicas ao lerem em tal língua-alvo. Essa demanda se constitui no âmbito da educação profissional técnica e tecnológica em Informática, na qual a leitura de textos especializados anglófonos é parte integrante da formação dos alunos. Esses aprendizes têm que não somente compreender um idioma, que é a lingua franca da ciência, como também apreender conceitos e terminologias relevantes à prática de seu ofício. À luz da Linguística de Corpus, bem como de teorias da Terminologia e dos estudos do léxico, foram levantadas as colocações especializadas através de duas ferramentas computacionais. A partir dos dados coletados, esses padrões lexicais foram observados em seus contextos de uso. Conclui-se ser relevante dar continuidade às análises realizadas neste estudo preliminar, uma vez que as mesmas demonstraram ser produtivas para o ensino de inglês instrumental no panorama educacional mencionado

Colocações especializadas na ciência da computação: uma proposta de estudo terminológico para fins de ensino de inglês

O objetivo deste trabalho é propor um estudo descritivo das colocações de cunho terminológico em artigos científicos em inglês no campo da Ciência da Computação. Assim, a razão do desenvolvimento deste projeto ocorre pela necessidade de estudantes e professores não nativos de reconhecer as convencionalidades léxicas ao lerem em tal língua-alvo. Essa demanda se constitui no âmbito da educação profissional técnica e tecnológica em Informática, na qual a leitura de textos especializados anglófonos é parte integrante da formação dos alunos. Esses aprendizes têm que não somente compreender um idioma, que é a lingua franca da ciência, como também apreender conceitos e terminologias relevantes à prática de seu ofício. À luz da Linguística de Corpus, bem como de teorias da Terminologia e dos estudos do léxico, foram levantadas as colocações especializadas através de duas ferramentas computacionais. A partir dos dados coletados, esses padrões lexicais foram observados em seus contextos de uso. Conclui-se ser relevante dar continuidade às análises realizadas neste estudo preliminar, uma vez que as mesmas demonstraram ser produtivas para o ensino de inglês instrumental no panorama educacional mencionado

Generación de biogas a partir de la degradación de residuos orgánicos de frigoríficos

Se presentan los primeros resultados obtenidos del estudio de los parámetros característicos de la degradación de residuos orgánicos colectados en un frigorífico de peces ubicado en Bella Vista – Corrientes- Argentina. Se armaron 8 reactores a escala de laboratorio y un digestor de 200 l instalado a campo abierto. Las temperaturas de trabajo en ambas situaciones fueron entre 25 y 35 °C, tiempo de retención hidráulico 30 días, y el contenido de estiércol en la suspensión: 10%, 25%, 50% y 100% en el laboratorio y 50% en el digestor de campo. Los reactores de laboratorio se hicieron funcionar de manera discontinua. Se midieron la cantidad de biogás generado y acumulado. La concentración de metano en el biogás generado a campo abierto varió entre 45% y 60%. Se concluyó que el tratamiento anaerobio del efluente colectado en el frigorífico es una opción de depuración biológica y técnica de generación de energía útil.The characteristic parameters of the degradation of organic waste collected in a fish slaughterhouse located in Bella Vista – Corrientes- Argentina were study using 8 laboratory scale reactors and 200 l digester. Temperatures in both situations were between 25 and 35 ° C, hydraulic retention time 30 days, and the content of manure in suspension: 10%, 25%, 50% and 100% in the laboratory and 50% in the digester field. Laboratory reactors were operated batchwise. Biogas generated and accumulated were measured. Methane concentration varied between 45% and 60%. The anaerobic treatment of effluent collected in a slaughterhouse, is an option of biological and technical debugging generating useful energy.Tema 6: Energía eólica, geotermia, biomasa y otras energías no convencionales.Facultad de Arquitectura y Urbanism