946 research outputs found
A nonequilibrium renormalization group approach to turbulent reheating
We use nonequilibrium renormalization group (RG) techniques to analyze the
thermalization process in quantum field theory, and by extension reheating
after inflation. Even if at a high scale the theory is described by a
non-dissipative theory, the RG running induces nontrivial
noise and dissipation. For long wavelength, slowly varying field
configurations, the noise and dissipation are white and ohmic, respectively.
The theory will then tend to thermalize to an effective temperature given by
the fluctuation-dissipation theorem.Comment: 8 pages, 2 figures; to appear in J. Phys. A; more detailed account of
the calculation of the noise and dissipation kernel
Effect of Vacuum on Venous Drainage: an Experimental Evaluation on Pediatric Venous Cannulas and Tubing Systems.
Introduction: To observe how vacuum assisted venous drainage (VAVD) may influence the flow in a cardiopulmonary bypass circuit with different size of venous lines and cannulas.
Methods: The experimental circuit was assembled to represent the cardiopulmonary bypass circuit routinely used during cardiac surgery. Wall suction was applied directly, modulated and measured into the venous reservoir. The blood flow was measured with a flow-meter positioned on the venous line. The circuit prime volume was replaced with group O date expired re-suspended red cells and Plasmalyte 148 to a hematocrit of 28% to 30%.
Results: In an open circuit with gravity siphon venous drain, angled cannulae drain more than straight ones regardless the amount of suction applied to the venous line (16 Fr straight cannula (S) drains 90 ml/min less than a 16 Fr angled (A) with a siphon gravity). The same flow can be obtained with lower cannula size and higher suction (i.e. 12 A with and -30 mmHg). Tables have been created to list how the flow varies according to the size of the cannulas, the size of the venous tubes, and the amount of suction applied to the system.
Conclusions: Vacuum assisted venous drainage allows the use of smaller cannulae and venous lines to maintain a good venous return, which is very useful during minimally invasive approaches. The present study should be considered as a preliminary attempt to create a scientific-based starting point for a uniform the use of VAVD.
Keywords: cardio-pulmonary bypass; experimental study; vacuum assisted drainage
Inflation and nonequilibrium renormalization group
We study de spectrum of primordial fluctuations and the scale dependence of
the inflaton spectral index due to self-interactions of the field. We compute
the spectrum of fluctuations by applying nonequilibrium renormalization group
techniques.Comment: 6 pages, 1 figure, submitted to J. Phys.
Genetic characterization of Indubrasil cattle breed population.
Abstract The Indubrasil breed was developed in the Brazilian region called Triângulo Mineiro as a result of a cross between zebu cattle. Initially, it was used as a terminal cross and currently it represents approximately 4.45% of all the Brazilian zebu cattle. Studies were conducted to estimate genetic parameters in the Indubrasil using pedigree information, however, until now, no study has been developed using large-scale genomic markers in this breed. Pedigree information are widely used to investigate population parameters; however, they can neglect some estimates when compared to the use of genomic markers. Therefore, the objective of this study was to investigate the population structure and the genetic diversity of Indubrasil cattle using a high-density Single Nucleotide Polymorphism (SNP) panel (Illumina BovineHD BeadChip 700k). Levels of genomic homozygosity were evaluated using three different approaches: Runs of homozygosity (FROH), % of homozygosis (FSNP), and inbreeding coefficient (Fx). Further, Runs of Homozygosity (ROH) segments conserved among the animals were investigated to identify possible regions associated with the breed characteristics. Our results indicate that even the Indubrasil breed having a small effective population size, the levels of homozygosity (FROH = 0.046) are still small. This was possibly caused by the cross conducted among different breeds for its development. It suggests no immediate risks associated with loss of genetic variation. This information might be used in breeding programs, for the breed conservation and for the expansion of the Indubrasil breed
Elaboração de fertilizante orgânico a partir dos recursos locais no assentamento Tamarineiro II Sul, Corumbá, MS.
Pelo solo ser 80% argiloso, numa região de calcário a vinte centímetros da superfície de algumas regiões da propriedade, e a água muito salobra, notou-se que muitas culturas sofrem para se desenvolver, pois o solo apresenta insuficiência de micronutrientes, como o zinco (Zn) e de macronutrientes, como o magnésio (Mg). O cultivo de plantas nos assentamentos de Corumbá- MS sofre a influência do solo e da água calcária, que formam uma crosta branca que é projetada no caule, levando a tal planta a parar de absorver os nutrientes do solo. Com base nas características que o solo apresenta, foi elaborado um fertilizante orgânico para suprir as necessidades da planta. O fertilizante pode ser utilizado puro, tanto foliar como direto no solo. Nos testes realizados com orégano, hortelã e poejo, foi possível observar os resultados após o terceiro dia, dependendo da cultura.Também em: SEMINÁRIO DE AGROECOLOGIA DE MATO GROSSO DO SUL, 4.; ENCONTRO DE PRODUTORES AGROECOLÓGICOS DE MS, 3., 2012, Glória de Dourados. O saber tradicional e o científico: a interação encurtando caminhos para o desenvolvimento sustentável: anais. Brasília, DF: Embrapa, 2012. 1 CD-ROM. Editado por: Leandro Fávio Carneiro, Milton Parron Padovan
Posição das câmaras de coleta para monitoramento da emissão de gases de efeito estufa do solo em plantios florestais de Pinus.
Rendimento do óleo essencial de Melissa officinalis L. em diferentes tempos de extração.
O presente trabalho teve como objetivo avaliar o rendimento do óleo essencial de Melissa officinalis L. em diferentes tempos de extração. M. officinalis é uma planta originária do Mediterrâneo e da Ásia, da família Lamiacea que possui, entre as várias atividades farmacológicas conhecidas, a atividade antiviral contra o vírus do herpes simples. Folhas de M. officinalis foram coletadas na unidade demosntrativa de plantas medicinais, aromáticas e condimentares da Embrapa Pantanal, em Corumbá MS, e trazidas ao Laboratório de Prospecção de Plantas Medicinais da Embrapa Pantanal, Corumbá-MS, selecionadas, secas em estufa a 40ºC e acondicionadas. As amostras foram então submetidas ao processo de hidrodestilação, por meio de aparelho do tipo Clevenger, utilizando-se, para cada repetição 40g de folhas desidratadas e 800mL de água destilada, em balão de fundo redondo. O delineamento utilizado foi o inteiramente casualiza do com três tratamentos (tempos de extração de 3h, 4h e 5h) e quatro repetições. O rendimento médio de óleo essencial de folhas de M. officinalis foi de 1,4, 1,7 e 2,4, em base seca, após 3h, 4h e 5h, respectivamente. Conclui-se que o tempo para se obter o maior rendimento é de 5h. Outros estudos estão em andamento para avaliar a composição química do óleo essencial em função do tempo de e xtração
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