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Search Results: 1 - 10 of 118927 matches for " José Carlos Batista;Cunha "
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Photomultiplier nonlinear response in time-domain laser-induced luminescence spectroscopy
Schip, Leandro José Bossy;Buzelatto, Bruno Phelippe;Batista, Fábio Roberto;Cunha, Carlos Jorge da;Dias Jr., Lauro Camargo;Novo, Jo?o Batista Marques;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000100034
Abstract: a new procedure to find the limiting range of the photomultiplier linear response of a low-cost, digital oscilloscope-based time-resolved laser-induced luminescence spectrometer (trls), is presented. a systematic investigation on the instrument response function with different signal input terminations, and the relationship between the luminescence intensity reaching the photomultiplier and the measured decay time are described. these investigations establish that setting the maximum intensity of the luminescence signal below 0.3v guarantees, for signal input terminations equal or higher than 99.7 ohm, a linear photomultiplier response.
Estimativa de parametros genéticos sob duas estratégias de avalia??o em híbridos intra e interespecíficos de capim-elefante
Assis, Liz Carolina da Silva Lagos Cortes;Lira, Mario de Andrade;Santos, Mércia Virginia Ferreira dos;Dubeux Júnior, José Carlos Batista;Cunha, Márcio Vieira da;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001200005
Abstract: the objective of this work was to evaluate the genetic parameters estimated in intra and interespecific hybrid families of elephant grass under two evaluation strategies: per se and genetically stratified mass selection. ten families of intraespecifc hybrids and ten families of interespecific hybrids were used. the characteristics evaluated were the following: plant height, plant agronomic score, dry matter content and dry matter production. it was estimated, for genetic parameters, heritability in the wide sense, variance, genetic and experimental variation coefficient and genetic, phenotypic and environmental correlation. the experiment was evaluated in a random block design with three repetitions. greater genetic variability for the studied characteristics were observed among the interespecific hybrids of elephant grass and pearl millet in comparison to the intraespecifc hybrids of elephant grass. heritability showed higher percentages for per se strategy among the studied hybrids. genetically stratified mass selection is less effective in removing the environmental effects aiming at improving experimental precision.
Spinors and the Weyl Tensor Classification in Six Dimensions
Carlos Batista,Bruno Carneiro da Cunha
Mathematics , 2012, DOI: 10.1063/1.4804991
Abstract: A spinorial approach to 6-dimensional differential geometry is constructed and used to analyze tensor fields of low rank, with special attention to the Weyl tensor. We perform a study similar to the 4-dimensional case, making full use of the SO(6) symmetry to uncover results not easily seen in the tensorial approach. Using spinors, we propose a classification of the Weyl tensor by reinterpreting it as a map from 3-vectors to 3-vectors. This classification is shown to be intimately related to the integrability of maximally isotropic subspaces, establishing a natural framework to generalize the Goldberg-Sachs theorem. We work in complexified spaces, showing that the results for any signature can be obtained by taking the desired real slice.
Repetibilidade e respostas de características morfofisiológicas e produtivas de capim-elefante de porte baixo sob pastejo
Viana, Bruno Leal;Mello, Alexandre Carneiro Le?o de;Lira, Mário de Andrade;Dubeux Júnior, José Carlos Batista;Santos, Mércia Virgínia Ferreira dos;Cunha, Márcio Vieira da;Ferreira, Geane Dias Gon?alves;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009001200024
Abstract: the objective of this study was to estimate the coefficients of repeatability and determination (r2) and the minimum number of measurements necessary to predict the real value of morphophysiological and yield variables, as well as the responses to sheep-grazing of dwarf elephant grass pasture. the experiment was carried out in a randomized block design with five treatments - taiwan a-146 2.27, taiwan a-146 2.37, taiwan a-146 2.114, merker méxico mx 6.31 and mott - and four replicates, over five grazing cycles, between september 2008 and april 2009. mean sward height, leaf area index (lai), light interception (li), mean leaf angles (mla), silage accumulation (sa) and silage accumulation rate (sar) were evaluated. for the variables lai, il and mean sward height of plants, in long cycles, only one measurement was necessary (r2 = 80%) to place them among the most predictable characteristics in the evaluation of elephant grass clones. assessments for sa and sar need longer experimental periods for greater reliability in the estimation of response variables. in dwarf elephant grass, light interception increases with sward height and lai.
Acute toxicity of Brosimum gaudichaudii Trécul. root extract in mice: determination of both approximate and median lethal doses
Cunha, Luiz Carlos da;Paula, José Realino de;Sá, Vinícius Augusto de;Amorim, Marcos Evaristo da Paix?o e;Barros, Isabel Cristina Medeiros;Brito, Luiz Augusto Batista;Silveira, Nusa da;
Revista Brasileira de Farmacognosia , 2008, DOI: 10.1590/S0102-695X2008000400006
Abstract: the brosimum gaudichaudii trécul. (bg) moraceae, with a high frequency in regions of the brazilian cerrado (shrubland) and popularly known as "mamacadela", holds photosensitizing furocoumarins. the bg's main therapeutic use is the treatment of vitiligo, a skin depigmentation disease that takes hold of approximately 1-2 % of the world population. there is one product on the marketplace (viticromin?), for which there is no scientific research available about its experimental toxicity, in spite of its proven clinical efficacy. therefore, the development of acute pre-clinical toxicity trials has been proposed (approximate lethal dose, ald, and median lethal dose, ld50) of the bg root exsudate in laboratory animals. male, albino mice weighing between 25 and 30 g, in good sanitation conditions have been used. the mice received water and food ad libitum. the bg powder was mixed in 0.9% saline solution and 0.5% cremophor and was administered po and ip. the ld50 was obtained through the lichtfield and wilcoxon (1949) method. a public domain software was used for the calculations. ten mice/dose were used - 6 groups for each administration via, including the control group - and the number of deaths within up to 14 days was considered; the control group received an emulsion made up by 0.9 saline solution and 0.5% cremophor. before establishing the ld50 and aiming at reducing the number of animals used, the dla was determined when 1 animal per dose was used (the next dose always 50% higher than the previous dose), until identifying the dose that led to the death of 1 animal. thus, the dla po was 3750 mg/kg and the dla ip, 2920 mg/kg. the ld50 po was 3517.54 mg/kg and the ld50 ip was 2871.76 mg/kg. the product was considered as of being of low toxicity, taking into account only the single dose acute toxicity.
Association between the morphological and productive characteristics in the selection of elephant grass clones
Cunha, Márcio Vieira da;Lira, Mario de Andrade;Santos, Mércia Virginia Ferreira dos;Freitas, Erinaldo Viana de;Dubeux Junior, José Carlos Batista;Mello, Alexandre Carneiro Le?o de;Martins, Kalina Gerciane Rodovalho;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000300004
Abstract: the objectives in this work were to study the association between the morphological and productive characteristics in pennisetum sp. clones, and to identify the morphological characteristics responsible for the productivity in pennisetum cp. clones. the canonical correlations were evaluated and the path analysis was made from the simple genotypic correlation matrix between the morphological and productive characteristics of eight pennisetum sp. clones (taiwan a-146 2.37, taiwan a-146 2.27, taiwan-146 2.114, merker méxico mx 6.31, mott, hv-241, elefante b and iri-381). the canonical correlations were significant at 1% probability by the chi-square test. the first pair of canonic factors, with correlation of 0.9999, related the plants with the highest dry matter content to plants with lower leaf area indexes, light perception and leaf angle. the second pair of canonic factors, with correlation of 0.9999, related the plants with the highest dry matter production to the plants with higher basal tiller density, height, and low green leaf number per tiller. the results of the path analysis indicated that the light interception is determinant in dry matter content expression of pennisetum sp. clones, while the basal tiller density and plant height are responsible for dry matter production in these clones.
Variabilidade e herdabilidade de caracteres qualitativos relacionados à qualidade de forragem de clones de capim-elefante na Zona da Mata de Pernambuco
Silva, Ant?nio Luiz Cordeiro da;Santos, Mércia Virginia Ferreira dos;Ferreira, Rinaldo Luiz Caraciolo;Dubeux Júnior, José Carlos Batista;Lira, Mario de Andrade;Cunha, Márcio Vieira da;Pereira, Antonio Vander;Araújo, Gherman Garcia Leal de;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000100006
Abstract: the objective of this research was to evaluate variability and heritability of quantitative traits related to forage quality of 32 clones of elephant grass (three local controls, from zona da mata de pernambuco, and the remaining from renace/cnpgl). a complete randomized design was used with additional controls and analyses of variance was applied by using the procedure of families with controls between rows. evaluation was performed during the dry period, at 60 days of growth. it was observed significant differences among clones for the traits acid detergent of leaf blade and stem organic matter, with means of 34.05 and 78.83%, respectively. in general, heritability of qualitative traits was low, including null values for crude protein and neutral detergent fiber of leaf blade and in vitro digestibility of dry matter of leaf blade and stem. chemical composition and digestibility of evaluated clones were similar. there are few possibilities of gain in selection for qualitative traits considering the low variability and heritability of the studied characters.
Potential of Caatinga forage plants in ruminant feeding
Santos, Mércia Virginia Ferreira dos;Lira, Mário de Andrade;Dubeux Junior, José Carlos Batista;Guim, Adriana;Mello, Alexandre Carneiro Le?o de;Cunha, Márcio Vieira da;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001300023
Abstract: caatinga is the most important biome for the livestock in the brazilian semi-arid region. this review paper aimed to present information on different forage aspects of caatinga vegetation for ruminant feeding. caatinga vegetation is formed mainly by shrubs and small trees, usually presenting thorns, deciduous leaves, and leaf abscission occurring frequently at the onset of the dry season. additional components of the botanical composition in this biome includes the families cactaceae, bromeliaceae, and a herbaceous component formed by grasses, legumes, and forbs, often presenting annual cycle. quantitative information of caatinga vegetation is scarce in the literature, mainly for the herbaceous stratum. methodological aspects such as lack of standardization across evaluations make comparison regarding forage potential of caatinga plant species difficult. index species must be identified within each caatinga type. quantitative aspects of biological n2 fixation by caatinga species have not been extensively studied. regarding forage nutritive value, it is necessary to study n availability for ruminants in caatinga plants, since large proportion of this element may bind to fiber components (adin). manipulation of caatinga vegetation is an alternative to change forage quantity and quality for grazing animals, affecting their performance as a result. studies measuring qualitative and quantitative variability of native forage resources from caatinga are mandatory in order to improve animal feeding management, with the ultimate goal of creating sustainable animal production based on caatinga vegetation.
Variabilidade e herdabilidade de caracteres morfológicos em clones de capim-elefante na Zona da Mata de Pernambuco
Silva, Ant?nio Luiz Cordeiro da;Santos, Mércia Virginia Ferreira dos;Dubeux Júnior, José Carlos Batista;Lira, Mario de Andrade;Ferreira, Rinaldo Luiz Caraciolo;Freitas, Erinaldo Viana de;Cunha, Márcio Vieira da;Silva, Maria da Concei??o;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001000005
Abstract: this research was carried out at to evaluate the variability and heritability of morphologic traits in 54 elephant grass clones (three local controls and 51 from the renace/cnpgl) in the forest zone in pernambuco. it was used a complete randomized block design with additional controls. three cuts were performed on the 60th day of regrowth. there were significant differences for stem diameter, basal and aerial tillers density, width of leaf 3, length of leaf 5, leaf blade percentage, stem percentage, and leaf/stem ratio. clones of renace are similar to the ones traditionally cultivated in the conditions of forest zone in pernambuco regarded to morphological characters. cultivar pioneiro showed early flourishing in the environmental conditions of this study. number of basal and aerial/metter tillers showed good heritability, evidencing little influence of the environment on variability among the clones. considering the variability among renace clones for basal and aerial tillers/m and leaf/stem ratio and the high heritability of these characters, it is possible to obtain genetic gains for these traits in the elephant grass breeding program in the forest zone in pernambuco.
Análise de trilha em caracteres produtivos de Pennisetum sob corte em Itambé, Pernambuco
Silva?, M?nica Alixandrina da;Lira, Mario de Andrade;Santos, Mércia Virgínia Ferreira dos;Dubeux Junior, José Carlos Batista;Cunha, Márcio Vieira da;Freitas, Erinaldo Viana de;
Revista Brasileira de Zootecnia , 2008, DOI: 10.1590/S1516-35982008000700007
Abstract: this work aimed to estimate the correlation coefficients, determining the direct and indirect effects (path analysis) of explanatory independent variables on total dry matter production (main dependent variables) of five elephant grass clones in five cuts accomplished at the forest zone of pernambuco. each experimental plot measured 24 m2 with 2 m2 of utile area. there was high correlation between almost all the independent variables and the main variable. the characteristic leaf blade number per tiller, however, explained better the potential of dry matter production and leaf blade dry matter production, acting, respectively, in a direct and indirect way on the explanatory variables.
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