A canonical transformation and the tunneling probability for the birth of an asymptotically DeSitter universe with dust

In the present work, we study the quantum cosmology description of closed Friedmann-Robertson-Walker models in the presence of a positive cosmological constant and a generic perfect fluid. We work in the Schutz's variational formalism. If one uses the scale factor and its canonically conjugated momentum as the phase space variables that describe the geometrical sector of these models, one obtains Wheeler-DeWitt equations with operator ordering ambiguities. In order to avoid those ambiguities and simplify the quantum treatment of the models, we introduce new phase space variables. We explicitly demonstrate that the transformation leading from the old set of variables to the new one is canonical. In order to show that the above canonical transformations simplify the quantum treatment of those models, we consider a particular model where the perfect fluid is dust. We solve the Wheeler-DeWitt equation numerically using the Crank-Nicholson scheme and determine the time evolution of the initial wave function. Finally, we compare the results for the present model with the ones for another model where the only difference is the presence of a radiative perfect fluid, instead of dust.Comment: Revtex4, 18 pages, 2 EPS figure

Rendimento de biomassa da cana-do-reino (Arundo donax L.).

bitstream/item/30324/1/boletim-42.pd

The cyclonic dryer: a numerical and experimental analysis of the influence of geometry on average particle residence time

Particle residence time is an extremely important variable in a cyclonic dryer project. With the goal of obtaining a device that conduces to a long particle residence time, the influence of cyclone dimensions on particle residence time and on the type of flow is discussed here. The research was based on a device with a very high ratio of cyclone diameter to other dimensions. Simulations were developed with computational fluid dynamics techniques by the use of the commercial code CFX 4.4® of AEA Technology. Particles were treated individually. The fit of a turbulence model was also discussed. Theoretical and experimental results showed that the dimensions of the conical part of the cyclone had a very important influence on flow and consequently on particle residence time. The influences of volumetric concentration and particle diameter on particle residence time were also observed.103112Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Transformação genética para resistência ao mofo branco do feijão comum.

Com o objetivo de interferir diretamente nos mecanismos de patogenicidade do fungo Sclerotinia sclerotiorum, plantas transgênicas de feijoeiro foram obtidas, via biobalística.CONAF

Geração de curva alométrica para avaliar as reservas de carbono em plantios de erva-mate, no sul do Brasil.

Este estudo foi realizado nos municípios de Machadinho e Barão de Cotegipe no Estado do Rio Grande do Sul, Brasil, durante o primeiro trimestre de 2007. Para a determinação da curva alométrica foram realizadas amostragens destrutivas de 30 árvores em áreas de produção de erva-mate, correspondentes a seis idades de cultivo: 4, 8, 10, 16, 22 e 25 anos, de forma a representar o ciclo produtivo da espécie florestal.A erva-mate é uma cultura característica da agricultura familiar da região Sul do Brasíl. Além de sua importância cultural é uma alternativa de geração de emprego, renda e de reposição florestal, com grande potencial de proporcionar serviços ambientais como o de seqüestro de carbono.Pelo estudo, o fluxo anual de carbono na biomassa aérea da erva-mate, é estimada, na média, em 20 t/CO2/ha/ ano, tendo como reserva no solo, mais de 207 tCO2/ha. A equação alométrica que mais se ajustou para estimar a biomassa total das árvores de erva-mate foi: Biomasa =-0,1255+0,8081*Idade+3,9672*Altura+3,6923*Biomassa folhas. O estudo demonstra um grande potencial de captura de CO2 no cultivo de ervamate caracterizando um serviço ambiental da atividade e suas possibilidades como um ativo financeiro na agricultura familiar da região sul do Brasil.bitstream/CNPF-2009-09/42628/1/BPD33.pdf1 CD-ROM

Avaliação de acessos de camu-camuzeiro em terra firme.

bitstream/item/39858/1/Com-Tec-17-Am-Oriental.pd

Iron and zinc retention in common beans (Phaseolus vulgaris L.) after home cooking.

Background: According to the World Health Organization (WHO), iron, iodine, and Vitamin A deficiencies are the most common forms of malnutrition, leading to severe public health consequences. The importance of iron and zinc in human nutrition and the number of children found to be deficient in these nutrients make further studies on retention in cooked grains and cooked bean broth important. Objectives: This work aimed to evaluate iron and zinc retention in six common bean (Phaseolus vulgaris L.) cultivars under the following conditions: raw beans, regular pot cooking, pressure cooking, with and without previous water soaking, and broth. Design: Determination of iron and zinc content in the raw, cooked bean grains and broth samples was carried out by Inductively Coupled Plasma (ICP) Optical Emission Spectrometry (Spectro Analytical Instrument Spectroflame P). All experiments and analyses were carried out in triplicate. Results: Overall, regardless of the cooking method, with or without previous water soaking, the highest zinc concentration was found in the cooked bean grains. However, pressure cooking and previous water soaking diminished iron retention in the cooked grains, while increasing it in the bean broth. Conclusion: The common bean was confirmed to be an excellent source of iron and zinc for human consumption, and it was suggested that beans should be consumed in a combined form, i.e. grain with bean broth

Supplementation of fetal bovine serum alters histone modification H3R26me2 during preimplantation development of in vitro proeduced bovine embryos.

e aim of this study was to evaluate the histone modification, H3R26me2 during pre-implantation development of IVP bovine embryos cultured with or without serum supplementation and how these in vitro treatments compared to in vivo embryos at the morula stage. After in vitro maturation and fertilization, bovine embryos were cultured with either 0 or 2.5% fetal bovine serum (FBS). Development was evaluated and embryos were collected and fixed at different stages during development (2-, 4-, 8-, 16-cell, morula and blastocyst). Fixed embryos were then used for immunofluorescence utilizing an antibody for H3R26me2. Images of stained embryos were analyzed as a percentage of total DNA. Embryos cultured with 2.5% FBS developed to blastocysts at a greater rate than 0%FBS groups (34.85+5.43% vs. 23.38+2.93%; P<0.05). Levels of H3R26me2 changed for both groups over development. In the 0%FBS group, the greatest amount of H3R26me2 staining was at the 4-cell (P<0.05), 16-cell (P<0.05) and morula (P<0.05) stages. In the 2.5%FBS group, only 4-cell stage embryos were significantly higher than all other stages (P<0.01). Morula stage in vivo embryos had similar levels as the 0%FBS group, and both were signifcantly higher than the 2.5%FBS group. These results suggest that the histone modification H3R26me2 is regulated during development of pre-implantation bovine embryos, and that culture conditions greatly alter this regulation. INDEX TERMS: Bovine, embryo development,Título em português: Suplementação com soro fetal bovino altera a modificação de histona H3R26me2 durante o período pré-implantacional em embriões bovinos produzidos in vitro

Emissões de Metano e Óxido Nitroso de Planossolo: Efeito do Manejo do Solo e da Cobertura Vegetal.

RESUMO- Em áreas de produção de arroz irrigado, a época e as operações de preparo do solo determinam potenciais distintos de incorporação de carbono (C) ao solo e de emissão de gases de efeito estufa (GEE). Realizou-se um trabalho para avaliar o efeito do manejo do solo e da cobertura vegetal sobre as emissões de metano (CH4) e óxido nitroso (N2O), durante o outono/inverno, de Planossolo cultivado com arroz irrigado. O estudo foi realizado de abril a outubro de 2013, em Capão do Leão-RS. Avaliaram-se três sistemas de preparo do solo: preparo antecipado de outono; preparo convencional de primavera e preparo com rolo-faca no outono. As coletas dos gases foram realizadas semanalmente, utilizando-se o método da câmara estática fechada. A época e as operações de preparo do solo proporcionaram potenciais distintos de emissão de metano e óxido nitroso em Planossolo durante o outono/inverno. As emissões totais de metano foram maiores na área preparada com rolo-faca, seguida daquela com preparo convencional e antecipado. Também as emissões totais de óxido nitroso foram maiores para o preparo com rolo-faca, seguida da área com preparo antecipado; o preparo convencional não proporcionou emissões de óxido nitroso. Em todos os sistemas de preparo, o metano foi o principal componente do potencial de aquecimento global parcial (PAGp) de Planossolo cultivado com arroz irrigado durante o período de entressafra