448 research outputs found

    Bioeconomic Model for Decision-Making on Fattening Beef-Cattle

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    Profitability and competitiveness of agricultural systems it is closely related with the technology used. Economic and financial appraisal of investments on pasture improvements, facilities, feed and management plans, etc. are often required in order to make decisions. A bio-economic simulation model was developed in order to support decision making on beef-cattle grazing fattening. The aim of the model is to show the relationship between the technological alternative analysed in physical terms as well as financial and economic. By this way it is possible to asset and relate the bio-economic impact of the different animal and pasture management alternative technologies. Results show that the model could be used to support decision making when using stocking rates between 0.8 and 2.5 heads/ha

    Revisiting the nonequilibrium phase transition of the triplet-creation model

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    The nonequilibrium phase transition in the triplet-creation model is investigated using critical spreading and the conservative diffusive contact process. The results support the claim that at high enough diffusion the phase transition becomes discontinuous. As the diffusion probability increases the critical exponents change continuously from the ordinary directed percolation (DP) class to the compact directed percolation (CDP). The fractal dimension of the critical cluster, however, switches abruptly between those two universality classes. Strong crossover effects in both methods make it difficult, if not impossible, to establish the exact location of the tricritical point.Comment: 7 pages, 12 figure

    Diffusive epidemic process: theory and simulation

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    We study the continuous absorbing-state phase transition in the one-dimensional diffusive epidemic process via mean-field theory and Monte Carlo simulation. In this model, particles of two species (A and B) hop on a lattice and undergo reactions B -> A and A + B -> 2B; the total particle number is conserved. We formulate the model as a continuous-time Markov process described by a master equation. A phase transition between the (absorbing) B-free state and an active state is observed as the parameters (reaction and diffusion rates, and total particle density) are varied. Mean-field theory reveals a surprising, nonmonotonic dependence of the critical recovery rate on the diffusion rate of B particles. A computational realization of the process that is faithful to the transition rates defining the model is devised, allowing for direct comparison with theory. Using the quasi-stationary simulation method we determine the order parameter and the survival time in systems of up to 4000 sites. Due to strong finite-size effects, the results converge only for large system sizes. We find no evidence for a discontinuous transition. Our results are consistent with the existence of three distinct universality classes, depending on whether A particles diffusive more rapidly, less rapidly, or at the same rate as B particles.Comment: 19 pages, 5 figure

    Restablecimiento de un canino tras mordedura de serpiente “yarará” (Bothrops sp.) en Corrientes, Argentina

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    Se describen los sĂ­ntomas y lesiones registradas en un perro mordido por una serpiente del genero Bothrops (“yarará”), en una zona rural cercana a la ciudad de Corrientes, Argentina. El veneno de esta vĂ­bora posee proteasas y fosfolipasas que inducen daño local (hemorragia, edema, necrosis), asĂ­ como hemorragia sistĂ©mica por acciĂłn de hemorraginas y metaloproteinasas (lesiĂłn de paredes capilares), agravada por la incoagulabilidad generada por enzimas semejantes a la trombina, que consumen el fibrinĂłgeno sanguĂ­neo. El canino revelĂł hemorragia a travĂ©s de dos orificios contiguos en una mejilla, la cual estaba dolorida, caliente y edematosa. No se registraron signos de hemorragia sistĂ©mica. Se administrĂł suero antiofĂ­dico bivalente anti-Bothrops y dexametasona, acompañados de fluidoterapia para proteger a los riñones. El tiempo de coagulaciĂłn activado se mantuvoprolongado hasta las 6 h, normalizĂĄndose a las 8 h de iniciado el tratamiento. Se postula que la precocidad de la intervenciĂłn y el buen estado fĂ­sico del animal fueron cruciales para su completa recuperaciĂłn

    The application of ecologically intensive principles to the systemic redesign of livestock farms on native grasslands: A case of co-innovation in Rocha, Uruguay

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    CONTEXT: Family-run cow-calf farms based on native grasslands exhibit low economic and social sustainability, as reflected in low family incomes and high workloads. Experimental results have shown that pasture–herd interaction management could improve native grasslands and animal productivity OBJECTIVE: This paper analyzes the extent to which the sustainability of family-run livestock farms based on native grasslands could be enhanced by a systemic redesign informed by ecological intensification practices. The research questions address the initial state of farm sustainability, key bottlenecks to improving farm sustainability, and changes in sustainability criteria achieved over three years of farm redesign. METHODS: The study was executed as part of a multi-level co-innovation project in Uruguay in which a team of scientist-practitioners and seven farm families participated in farm characterization, diagnosis, and redesign. The farm characterization took the form of indicators to describe the farms’ management and bio-physical subsystems. Redesign plans were negotiated between the research team and the farmers. Frequent monitoring and evaluation cycles enabled finetuning across the years of implementation. RESULTS AND CONCLUSION: Improvements were observed in the economic indicators gross margin (+55%), return to labor (+71%), and family income (+53%) and in the social indicator workload ( 22%), and the environmental indicators bird diversity and ecosystem integrity index were maintained or increased slightly. These changes were explained by the uptake of coherent sets of ecological intensification practices causing changes in forage height (+30%), forage allowance (+69%), pregnancy (+22), weight of weaning calf per mating cow (+32%), and presence of tussocks (+65%). Ecological intensification principles resulted in synergistic positive effects between productivity–biodiversity tradeoffs and the scope for enhanced farm resilience and stability. SIGNIFICANCE: Cow-calf family-run farms can be transformed to produce positive environmental and social effects and viable economic results. The implementation of projects in a co-innovation context may be taken as a guide to scaling up and scaling out the ecological intensification of livestock production on native grasslands, contributing to an extension system at the national level with the aim of improving cow-calf systems sustainability.EstaciĂłn Experimental Agropecuaria BarilocheFil: Ruggia, Andrea. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Produccion Familiar. Estacion Experimental INIA Las Brujas; UruguayFil: Dogliotti, Santiago. Universidad de la RepĂșblica. Facultad de AgronomĂ­a. Departamento de Produccion Vegetal; UruguayFil: Aguerre, Maria Veronica. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Produccion Familiar. Estacion Experimental INIA Las Brujas; UruguayFil: Albicette, Maria Marta. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Produccion Familiar. Estacion Experimental INIA Las Brujas; UruguayFil: Blumetto, Oscar. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Produccion Familiar. Estacion Experimental INIA Las Brujas; UruguayFil: Cardozo, Geronimo. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Pasturas y Forrajes. Estacion Experimental INIA Treinta y Tres; UruguayFil: Leoni, Carolina. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Produccion Familiar. Estacion Experimental INIA Las Brujas; UruguayFil: Quintans, Graciela. Instituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Carne y Lana. Estacion Experimental INIA Treinta y Tres; UruguayFil: Scarlato, Santiago. nstituto Nacional de Investigacion Agropecuaria (INIA). Programa Nacional de Investigacion en Produccion Familiar. Estacion Experimental INIA Las Brujas; UruguayFil: Tittonell, Pablo Adrian. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Agropecuaria Bariloche; ArgentinaFil: Tittonell, Pablo Adrian. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Rossing, Walter A.H. Wageningen University and Research. Farming Systems Ecology, Plant Sciences Group; Holand

    Laranja de polpa vermelha: um estudo fĂ­sico-quĂ­mico e sensorial.

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    Objetivou-se nesse estudo identificar a percepção dos consumidores brasileiros frente ao consumo de laranjas do grupo umbigo de polpa vermelha (Citrus sinensis [L.] Osbeck), bem como gerar informaçÔes que auxiliem no seu maior consumo. Realizou-se primeiramente a caracterização fĂ­sico-quĂ­mica da laranja de polpa vermelha cultivar Cara Cara e da laranja de polpa amarela cultivar Navelina, traçando um paralelo entre elas que indicasse os potenciais benefĂ­cios nutricionais. A caracterização fĂ­sico-quĂ­mica compreendeu as anĂĄlises de pH, acidez titulĂĄvel, sĂłlidos solĂșveis totais, ĂĄcido ascĂłrbico e os compostos bioativos (conteĂșdo de carotenoides, flavonoides totais e fenĂłis totais). Ambas as amostras apresentaram caracterĂ­sticas desejĂĄveis de acidez e alto conteĂșdo de ĂĄcido ascĂłrbico (superior a 55 mg.100g-1 de porção comestĂ­vel). A cultivar Cara Cara indicou possuir maiores teores de compostos bioativos. A anĂĄlise sensorial foi composta pelo teste de aceitação, com escala hedĂŽnica de sete pontos, apresentando mĂ©dias superiores a 6 (gostei muito e gostei moderadamente) na maioria dos atributos das laranjas estudadas e o Teste de Perfil Descritivo, que revelou importantes descritores de diferenças entre as laranjas. Concluindo-se que, estas avaliaçÔes foram capazes de indicar importantes informaçÔes a serem usadas nas estratĂ©gias de marketing a fim de promover o maior consumo de laranjas de umbigo de polpa vermelha, como os valores superiores de compostos bioativos e atributos sensoriais positivos.bitstream/item/221210/1/l6capitulo6.pd

    Targeted chemical and sensory profiling to guide consumption of blood orange.

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    The objective of this study was to identify the perception of consumers regarding the consumption of blood oranges as well as to generate information that helps in their greater consump-tion. The physical-chemical characterization of the blood orange, cultivar Cara Cara, and the yellow-pulp orange, cultivar Bahia, was carried out, drawing a parallel between them that indicated their potential nutritional benefits. Both samples showed desirable characteristics, Cara Cara has higher levels of carotenoids, flavonoids and total phenols. The sensorial analysis revealed important descriptors of differences between oranges and was possible to identify factors that characterized the mar-keting and consumption of blood oranges, which were related to the consumption, quality, health and, perception of this type of fruit. It was concluded that these evaluations were able to indicate important characteristics to be used in marketing stra-tegies in order to promote the greater consumption of oranges with red pulp, exploring their bioactive benefits

    Exclusive neuronal expression of SUCLA2 in the human brain

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    SUCLA2 encodes the ATP-forming subunit (A-SUCL-) of succinyl-CoA ligase, an enzyme of the citric acid cycle. Mutations in SUCLA2 lead to a mitochondrial disorder manifesting as encephalomyopathy with dystonia, deafness and lesions in the basal ganglia. Despite the distinct brain pathology associated with SUCLA2 mutations, the precise localization of SUCLA2 protein has never been investigated. Here we show that immunoreactivity of A-SUCL- in surgical human cortical tissue samples was present exclusively in neurons, identified by their morphology and visualized by double labeling with a fluorescent Nissl dye. A-SUCL- immunoreactivity co-localized >99% with that of the d subunit of the mitochondrial F0-F1 ATP synthase. Specificity of the anti-A-SUCL- antiserum was verified by the absence of labeling in fibroblasts from a patient with a complete deletion of SUCLA2. A-SUCL- immunoreactivity was absent in glial cells, identified by antibodies directed against the glial markers GFAP and S100. Furthermore, in situ hybridization histochemistry demonstrated that SUCLA2 mRNA was present in Nissl-labeled neurons but not glial cells labeled with S100. Immunoreactivity of the GTP-forming subunit (G-SUCL-) encoded by SUCLG2, or in situ hybridization histochemistry for SUCLG2 mRNA could not be demonstrated in either neurons or astrocytes. Western blotting of post mortem brain samples revealed minor G-SUCL- immunoreactivity that was however, not upregulated in samples obtained from diabetic versus non-diabetic patients, as has been described for murine brain. Our work establishes that SUCLA2 is expressed exclusively in neurons in the human cerebral cortex

    Double-Stranded RNA Attenuates the Barrier Function of Human Pulmonary Artery Endothelial Cells

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    Circulating RNA may result from excessive cell damage or acute viral infection and can interact with vascular endothelial cells. Despite the obvious clinical implications associated with the presence of circulating RNA, its pathological effects on endothelial cells and the governing molecular mechanisms are still not fully elucidated. We analyzed the effects of double stranded RNA on primary human pulmonary artery endothelial cells (hPAECs). The effect of natural and synthetic double-stranded RNA (dsRNA) on hPAECs was investigated using trans-endothelial electric resistance, molecule trafficking, calcium (Ca2+) homeostasis, gene expression and proliferation studies. Furthermore, the morphology and mechanical changes of the cells caused by synthetic dsRNA was followed by in-situ atomic force microscopy, by vascular-endothelial cadherin and F-actin staining. Our results indicated that exposure of hPAECs to synthetic dsRNA led to functional deficits. This was reflected by morphological and mechanical changes and an increase in the permeability of the endothelial monolayer. hPAECs treated with synthetic dsRNA accumulated in the G1 phase of the cell cycle. Additionally, the proliferation rate of the cells in the presence of synthetic dsRNA was significantly decreased. Furthermore, we found that natural and synthetic dsRNA modulated Ca2+ signaling in hPAECs by inhibiting the sarco-endoplasmic Ca2+-ATPase (SERCA) which is involved in the regulation of the intracellular Ca2+ homeostasis and thus cell growth. Even upon synthetic dsRNA stimulation silencing of SERCA3 preserved the endothelial monolayer integrity. Our data identify novel mechanisms by which dsRNA can disrupt endothelial barrier function and these may be relevant in inflammatory processes
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