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Search Results: 1 - 10 of 262782 matches for " Silva Davi C. "
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Características funcionais de folhas de sol e sombra de espécies arbóreas em uma mata de galeria no Distrito Federal, Brasil
Rossatto, Davi Rodrigo;Takahashi, Frederico Scherr Caldeira;Silva, Lucas de Carvalho Ramos;Franco, Augusto César;
Acta Botanica Brasilica , 2010, DOI: 10.1590/S0102-33062010000300007
Abstract: gallery forest is a forest formation that covers about 10% of the cerrado biome and represents about 1/3 of cerrado tree diversity in brazil. recent studies demonstrate the importance of gallery forest in central regions of brazil, but little is known about the physiology and plasticity of gallery forest species in relation to environmental variability, particularly in terms of light availability. in this study we compared in situ physiological and nutritional aspects of shade and sun leaves, in ten tree species commonly found in gallery forests. relative to shade leaves, sun leaves had higher values of co2 assimilation rates on an area basis (aarea), of stomatal conductance (gs), of quantum yield of photosystem ii (φpsiil); and a larger fraction of psii centers in the open state (ql), while shade leaves showed higher specific leaf area. however, shade and sun leaves did not differ in terms of leaf water potential, co2 assimilation on a mass basis and in leaf concentrations of macronutrients. φpsii and gs were the main factors that influenced aarea in sun leaves, while only φpsii significantly affected aarea of shade leaves. the differences found here demonstrate that, like in other forest formations worldwide, gallery forest trees are able to acclimate to contrasting irradiance levels that typically occur in this type of environment.
A Short and Stereoselective Synthesis of the Sex Pheromone of Bonagota cranaodes (Lepidoptera: Tortricidae)
Simonelli, Fabio;Oliveira, Alfredo R.M.;Marques, Francisco A.;Silva, Davi C.;
Journal of the Brazilian Chemical Society , 1998, DOI: 10.1590/S0103-50531998000400009
Abstract: a stereoselective synthesis of (3e,5z)-dodecadienyl acetate, the sex pheromone of the leafroller moth bonagota cranaodes, was efficiently carried out using a methodology based on the coupling of z-alkenyl cuprate with 4-iodo-3-butyn-1-ol in the key step.
Valida??o de metodologia analítica para doseamento de solu??es de lapachol por CLAE
Fonseca, Said G. C.;Silva, Leila B. L. da;Castro, Rebeka F.;Santana, Davi P. de;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000100026
Abstract: lapachol is a naphthoquinone found in several species of the bignoniaceae family possessing mainly anticancer activity. the present work consists of the development and validation of analytical methodology for lapachol and its preparations. the results here obtained show that lapachol has a low quantification limit, that the analytical methodology is accurate, reproducible, robust and linear over the concentration range 0.5-100 μg/ml of lapachol.
Desenvolvimento e valida o de método analítico para quantifica o de diclofenaco de dietilam nio em pele humana por cromatografia líquida de alta eficiência
JOSé ALEXSANDRO SILVA,DANILO C.G. BEDOR,CARLOS E.M. SOUSA,DAVI P. SANTANA
Revista de Ciências Farmacêuticas Básica e Aplicada , 2010,
Abstract: Foi desenvolvido e validado neste estudo um método analítico para quantifica o de diclofenaco de dietilam nio em pele humana por cromatografia líquida de alta eficiência, segundo a Resolu o 899/2003 da Agência Nacional de Vigilancia Sanitária (ANVISA). Empregou-se cromatografia em fase reversa com coluna C18 150 x 4,6 mm, 5 μm Shimpack , à temperatura de 40 oC e fase móvel, constituída por mistura de acetonitrila e tamp o fosfato de sódio 20 mM pH 3,0 (70:30, v/v) com fluxo de 1,2 mL min-1. Os analitos foram detectados por UV a 280 nm e o método foi especifico, preciso, exato, robusto e linear no intervalo de 0,05 a 20 μg mL-1 (R2 = 0,998), mostrando que pode ser utilizado em estudos de penetra o cutanea in vitro tendo como modelo de membrana a pele humana. Palavras-chave: Diclofenaco dietilam nio. Reten o cutanea. Valida o. ABSTRACT Development and validation of an analytical method for quantitation of diclofenac diethylamine in human skin by high performance liquid chromatography An analytical method has been developed and validated for the quantitation of diclofenac diethylamine (DDA) in human skin by high performance liquid chromatography (HPLC), in accordance with Regulation 899/2003 of the National Sanitary Surveillance Agency (ANVISA). The HPLC column was a reversed-phase Shimpack C18, with a 5 μm particle bed, measuring 150 x 4.6 mm i.d., eluted isocratically at 40 C with 20 mM sodium phosphate buffer (pH 3.0):acetonitrile (30:70, v/v), the mobile phase flowing at 1.2 mL min-1. Analytes were measured by a UV detector set at 280 nm. The results revealed that the method was specific, precise, accurate, robust and linear (R2=0.998) in the range from 0.05 to 20 μg mL-1. Therefore, it can safely be used to assess DDA in vitro penetration of human skin in kinetic studies. Keywords: Diclofenac diethylamine. Human skin retention. Validation.
Valida o de metodologia analítica para doseamento de solu es de lapachol por CLAE
Fonseca Said G. C.,Silva Leila B. L. da,Castro Rebeka F.,Santana Davi P. de
Química Nova , 2004,
Abstract: Lapachol is a naphthoquinone found in several species of the Bignoniaceae family possessing mainly anticancer activity. The present work consists of the development and validation of analytical methodology for lapachol and its preparations. The results here obtained show that lapachol has a low quantification limit, that the analytical methodology is accurate, reproducible, robust and linear over the concentration range 0.5-100 μg/mL of lapachol.
AVALIA O DA EROS O NA MARGEM DIREITA DO RIO PARAGUAI A JUSANTE DA PRAIA DO JULI O MUNICíPIO DE CACERES-MT - EROSION EVALUATION IN PARAGUAY RIVER RIGHT BANK DOWNSTREAM OF THE BEACH OF JULI O CáCERES CITY-MT
Aguinaldo Silva; Célia Alves de Souza; Hiran Zani; Davi Rezende de Freitas
Revista Geográfica Acadêmica , 2007,
Abstract: The basin of the Paraguay River comes in recent years being of intense occupation and its canal hassuffered modifications in its dynamics. The objective of the study was to verify the dynamics of the bank,through the measurements of the erosion of the right bank of the Paraguay River, downstream the Juli o’sbeach, next to highway BR 174. The studied area was in Cáceres city, in Mato Grosso State, located inthe coordinates: 16°04’2.10" – 16°04’10" S and 57°42’24" and 57°42’18" W. It was adopted the followingmethodological procedures: space analysis of the morphologic aspect of the bank, measurements throughprops of the lateral erosion and quantification of the erosion. In the results, the water dynamics (outflowand oscillation in the water level), the characteristics and the evolution of the bank erosion was discussed.
A Short and Stereoselective Synthesis of the Sex Pheromone of Bonagota cranaodes (Lepidoptera: Tortricidae)
Simonelli Fabio,Oliveira Alfredo R.M.,Marques Francisco A.,Silva Davi C.
Journal of the Brazilian Chemical Society , 1998,
Abstract: A stereoselective synthesis of (3E,5Z)-dodecadienyl acetate, the sex pheromone of the leafroller moth Bonagota cranaodes, was efficiently carried out using a methodology based on the coupling of Z-alkenyl cuprate with 4-iodo-3-butyn-1-ol in the key step.
Padr?es de uso do tempo por novilhos em pastagem consorciada de azevém anual e aveia-preta
Baggio, Carolina;Carvalho, Paulo César de Faccio;Silva, Jamir Luís Silva da;Rocha, Lemar Maciel da;Bremm, Carolina;Santos, Davi Teixeira dos;Monteiro, Alda Lucia Gomes;
Revista Brasileira de Zootecnia , 2008, DOI: 10.1590/S1516-35982008001100002
Abstract: aiming to assess the steer grazing behavior, an experiment was carried out with pastures composed by italian ryegrass (lolium multiflorum lam.) and black oat (avena strigosa schreb) submitted to different sward heights (10, 20, 30, and 40 cm). the sward heights were distributed in an experimental randomized block design with three replicates. data was recorded by visual assessment, from sunrise until sundown, in three evaluation dates, two in the vegetative stage and one in the reproductive stage. the evaluated variables were grazing time, rumination time, idling time, number and length of meals, and number and length of meals intervals. results indicated that with increasing sward height the animals reduced grazing time and the meal length as well, however, the ruminating time increased. the variables such as idling time, number of meals and number/length of intervals were not influenced by the sward surface height. the results showed changes in the animal grazing behavior due to the variations in sward height management.
Anisotropic Cosmological Constant and the CMB Quadrupole Anomaly
Davi C. Rodrigues
Physics , 2007, DOI: 10.1103/PhysRevD.77.023534
Abstract: There are evidences that the cosmic microwave background (CMB) large-angle anomalies imply a departure from statistical isotropy and hence from the standard cosmological model. We propose a LCDM model extension whose dark energy component preserves its nondynamical character but wield anisotropic vacuum pressure. Exact solutions for the cosmological scale factors are presented, upper bounds for the deformation parameter are evaluated and its value is estimated considering the elliptical universe proposal to solve the quadrupole anomaly. This model can be constructed from a Bianchi I cosmology with cosmological constant from two different ways: i) a straightforward anisotropic modification of the vacuum pressure consistently with energy-momentum conservation; ii) a Poisson structure deformation between canonical momenta such that the dynamics remain invariant under scale factors rescalings.
Evolution of Anisotropies in Eddington-Born-Infeld Cosmology
Davi C. Rodrigues
Physics , 2008, DOI: 10.1103/PhysRevD.78.063013
Abstract: Recently a Born-Infeld action for dark energy and dark matter that uses additional affine connections was proposed. At background level, it was shown that the new proposal can mimic the standard cosmological evolution. In Bianchi cosmologies, contrary to the scalar field approach (e.g., Chaplygin gas), the new approach leads to anisotropic pressure, raising the issues of stability of the isotropic solution under anisotropic perturbations and, being it stable, how the anisotropies evolve. In this work, the Eddington-Born-Infeld proposal is extended to a Bianchi type I scenario and residual post-inflationary anisotropies are shown to decay in time. Moreover, it is shown that the shears decay following a damped oscillatory pattern, instead of the standard exponential-like decay. Allowing for some fine tuning on the initial conditions, standard theoretical bounds on the shears can be avoided.
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