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Search Results: 1 - 10 of 208722 matches for " Wagner F da;Pereira "
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Agronomic and economic viability of intercropping onion and lettuce
Mota, Wagner F da;Pereira, Rosimeire D;Santos, Gizeli de S;Vieira, Janiele Cássia B;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000200028
Abstract: the study aimed to evaluate the agronomic and economic performance of intercropping onion and lettuce on four plant densities of each species. the experiment was set up in completely randomized blocks, with four replications and treatments arranged in a 4 x 4 factorial. treatments resulted from a combination of four (100, 80, 60, and 40% of recommended plant densities in monoculture) plant densities for both lettuce and onion. intercropping did not affect the agronomic performance of onion or lettuce. higher plant densities (100% for both vegetables) resulted in higher lettuce and onion yields. the best economic results were observed using (a) onion at 80% of plant density combined with lettuce at 40 and 100% and (b) onion at 100% and lettuce at all densities (40 to 100%).
Associa??o de Rhizoctonia solani Grupo de Anastomose 4 (AG-4 HGI e HGIII) à espécies de plantas invasoras de área de cultivo de batata
Silva-Barreto, Fátima Aparecida da;Pereira, Wagner Vicente;Ciampi, Maisa Boff;Camara, Marcos Paz Saraiva;Ceresini, Paulo Cezar;
Summa Phytopathologica , 2010, DOI: 10.1590/S0100-54052010000200007
Abstract: the anastomosis groups 3 and 4 (ag-3 and ag-4) of the fungus rhizoctonia solani are important groups associated with potatoes worldwide. in brazil, the ag-3 is reported affecting mainly potatoes and tobacco. the ag-4 cause considerable losses in crops of economic importance, such as soybean, beans and peanuts and may also occur in vegetables such as spinach, pepper, broccoli, tomatoes, potatoes and fruit such as melons. the association of r. solani with invasive plants was recently established in potato production areas from brasília, df. however, there is no information about the etiology of the pathogen as well as the role of invasive species as alternative hosts in the life cycle of the pathogen. the objective of this study was to characterize isolates of r. solani obtained from potatoes and three other invasive plant species associated with areas of potato production: shoo-fly plant [nicandra physaloides (l.) pers., solanaceae], pigweed (portulaca oleracea l., portulacaceae), and low-amaranth (amaranthus deflexus l., amaranthaceae). it was confirmed the hypothesis that the r. solani isolates obtained from pigweed, low-amaranth and shoo-fly plant belong to the anastomosis group 4 and, except for the isolate from pigweed, are pathogenic to potatoes. these isolates were cross pathogencic to all the three weed species tested and also to american nightshade (solanum americanum mill.), another solanaceae invasive of potato fields. the placement of the isolates in the group ag-4 hgi or in the group ag-4 hgiii (isolate from caruru) was confirmed by cultural and molecular characteristics (sequencing of the its-5.8s region of rdna). the results of this study provide important implications for the management of the rhizoctonia root rot in potatoes.
Journal of the Chilean Chemical Society , 2007, DOI: 10.4067/S0717-97072007000300010
Abstract: since the biological activity of [ruiii(nh3)4(catechol)]+ has never been tested, its cytotoxicity to glial cells was assayed and correlated with its redox properties. coordinated catechol oxidizes faster than catechol in the presence of oxygen, but controlled potential electrolysis showed that its oxidation involves only one-electron. however, the oxidation of the free ligand by oxygen involves two electrons, which could generate more reactive oxygen species. indeed, catechol was more cytotoxic than [ruiii(nh3)4(catechol)]+ complex to human glioblastoma gl-15 cells and also to rat astrocytes. [ruiii(nh3)4(catechol)]+-induced cytotoxicity was related to the generation of reactive oxygen species and [ruc1(nh3)5]2+. however, other mechanisms should be involved since antioxidant enzymes and deferoxamine only partially protected gl-15 cells
Application of Finite Elements Method for Structural Analysis in a Coffee Harvester  [PDF]
Evandro Pereira da Silva, Fábio Moreira da Silva, Ricardo Rodrigues Magalh?es
Engineering (ENG) , 2014, DOI: 10.4236/eng.2014.63017

Stress concentration and large displacements are usual problems in the components of the structure of agricultural machinery such harvesters coffee, and that finite element method (FEM) can be a tool to minimize its effects. The goal of this paper is to get results of stresses and displacements of a coffee harvester structure by using FEM for static simulation. The main parts of the coffee harvester analyzed were: engine frame, body right and left sides, front and rear end, main beam, coffee reservoir, wheels and fuel tank. Two different design concepts of a coffee harvester machine were analyzed (structure with rear wheels aligned and misaligned) and the results were compared. It was observed that the model with rear wheels misaligned showed maximum displacement lower than the model with rear wheels aligned. Although higher stress was found in the rear wheels misaligned, it was observed that average stresses for the misaligned wheels design were lower in most structural components analyzed. Based on FEM results, the coffee harvester machine with misaligned rear wheels was built and subjected to operational tests without showing any structural failure.

Seven years of measurements of aerosol scattering properties, near the surface, in the southwestern Iberia Peninsula
S. N. Pereira, F. Wagner,A. M. Silva
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2011,
Abstract: Aerosol scattering properties, near the surface (at about 10 m height), were measured during a period of seven years (2002–2008) at évora, Portugal. The average (and median) scattering and backscattering coefficients, at the wavelength of 550 nm, were found to be 42.5 Mm 1 (29.9 Mm 1) and 5.9 Mm 1 (4.4 Mm 1), respectively. Also, the average and median scattering ngstr m exponent (1.4 and 1.5) indicate that scattering was, in general, dominated by sub-micrometer particles. Both seasonal and daily cycles are shown, which were related to local production and transport of particles from elsewhere. Summer and winter average values of the scattering coefficient, at the wavelength of 550 nm (47 and 54 Mm 1, respectively), correspond to a significant increase in the aerosol particle concentration when compared with spring and fall (35 and 37 Mm 1, respectively). Also, the average increase in the ngstr m exponent for summer and winter seasons is consistent with the input of sub-micrometer particles from anthropogenic origin in winter and forest fires in summer. Back-trajectory analysis indicated that the site was regularly under the influence of air masses from the Atlantic area, with low particle loads (low scattering coefficients), but as the influence of transport from the continent (Iberia Peninsula) increased, the aerosol particle load was observed to increase as well as the relative importance of fine particles over coarse ones, approaching the features observed at the site during European air masses influence.
Continuous measurements of near surface aerosols in the south-western European (Portugal) region in 2006–2008
S. N. Pereira, F. Wagner,A. M. Silva
Advances in Science and Research (ASR) , 2009, DOI: 10.5194/asr-3-1-2009
Abstract: Scattering and absorption coefficients near the ground were measured in évora, Portugal, in the period of 2006 to 2008. The average scattering coefficient, at the wavelength of 550 nm, for the whole period of measurements was found to be 40.3 Mm 1 and the absorption coefficient, at the wavelength of 670 nm, 8.6 Mm 1. These values are comparable to those measured in rural or background locations and reflect the small size of the city and relatively low magnitude of anthropogenic production at the site. A marked seasonal variation was found for the absorption coefficient, with a significant increase from 5.8 Mm 1, in summer, to 13.4 Mm 1, in winter. Regarding black carbon mass concentrations, this twofold increase, from 0.9 to 2.0 μgm 3, is mainly attributed to the wood combustion used for heating in conjunction with lower boundary layer mixing heights. The average scattering coefficient presented a more complex behaviour, although with a tendency for higher values in winter and lower values in spring.
Modelling a DR shaft operated with pure hydrogen using a physical-chemical and CFD approach
Andrea Ranzani Da Costa,D. Wagner,F. Patisson,D. Ablitzer
Physics , 2009,
Abstract: The hydrogen-based route could be a valuable way to produce steel considering its low carbon dioxide emissions. In ULCOS, it is regarded as a long-term option, largely dependent on the emergence of a hydrogen economy. To anticipate its possible development, it was decided to check the feasibility of using 100% H2 in a Direct Reduction shaft furnace and to determine the best operating conditions, through appropriate experimental and modelling work. We developed from scratch a new model, called REDUCTOR, for simulating this process and predicting its performance. This sophisticated numerical model is based on the mathematical description of the detailed physical, chemical and thermal phenomena occurring. In particular, kinetics were derived from experi-ments. The current version is suited to the reduction with pure hydrogen, but an extension of the model to CO is planned so that it will also be adapted to the simulation and optimisation of the current DR processes. First re-sults have confirmed that the reduction with hydrogen is much faster than that with CO, making it possible to design a hydrogen-operated shaft reactor quite smaller than current MIDREX and HYL.
Identifica??o de extratos etanólicos de madeiras utilizando seu espectro eletr?nico de absor??o e análise multivariada
Silva, Alexandre Ataide da;Nascimento, Eduardo Sanches Pereira do;Cardoso, Daniel Rodrigues;Franco, Douglas Wagner;
Química Nova , 2012, DOI: 10.1590/S0100-40422012000300023
Abstract: the application of multivariate analysis to spectrophotometric (uv) data was explored for distinguishing extracts of cacha?a woods commonly used in the manufacture of casks for aging cacha?as (oak, cabreúva-parda, jatobá, amendoim and canela-sassafrás). absorbances close to 280 nm were more strongly correlated with oak and jatobá woods, whereas absorbances near 230 nm were more correlated with canela-sassafrás and cabreúva-parda. a comparison between the spectrophotometric model and the model based on chromatographic (hplc-dad) data was carried out. the spectrophotometric model better explained the variance data (pc1 + pc2 = 91%) exhibiting potential as a routine method for checking aged spirits.
Influência do tratamento pós-colheita com cálcio na conserva??o de jabuticabas
Revista Brasileira de Fruticultura , 2002, DOI: 10.1590/S0100-29452002000100011
Abstract: the jabuticaba fruits has great acceptance for "in natura" consumption. however, it is highly perishable, with short postharvest life. calcium ions are capable to delay the senescence and to maintain fruit firmness. the objective of this experiment was to increase shelf life of jabuticabas, by means of its immersion in solution of cacl2. the fruits were harvested fully ripe, immerged in solution of cacl2 40 g.l-1 for 0; 5; 10; 20; 40 and 60 minutes and stored at room temperature and relative humidity for six days. larger times of immersion resulted in larger retention of fruit firmness, although without affecting its fresh matter loss. in all immersion times there were reduction of firmness and increasing of fresh matter loss of the fruits with increasing of storage period. longer immersion times reduced respiration rates. respiration rate reduced, in all immersion times, until the fourth day after the harvest, followed by increasing after the sixth day. the acidity increased during storage and reduced when immersion times in cacl2 varied from 0 to 20 min and then increased in the fruits immerged for 40 and 60 min. in spite of the described effects, there was not great contribution of calcium in the extension of commercialization period of the jabuticaba, fruits.
Santos-Wagner, Vania Maria Pereira dos,Silva, Sandra Aparecida Fraga da
Revista Eletr?nica de Educa??o , 2012,
Abstract: Nesse artigo trazemos resultados de uma investiga o com professoras das séries iniciais num grupo de estudos sobre matemática. Este estudo de caso longitudinal de dois anos caracterizou-se numa pesquisa qualitativa com perspectiva humanística. Nosso objetivo neste trabalho é apresentar algumas aprendizagens de conhecimento matemático e pedagógico matemático de duas professoras a partir da dinamica proporcionada pelo grupo de estudos. Os dados foram coletados nos encontros semanais do grupo e nas aulas das quais participamos e/ou observamos. Nesse grupo, as professoras se respeitavam, ouviam e eram ouvidas em suas vitórias e anseios, opinavam, lan avam propostas e contribuíam para a constru o dos diferentes conhecimentos. Esse comportamento influenciou as aprendizagens e as atitudes das professoras em rela o à matemática, resultando em ressonancias em suas práticas em sala de aula. Obtivemos evidências de melhoria e de aprendizagem de dois tipos de conhecimentos: de conteúdo matemático e pedagógico matemático. De conhecimentos dos conteúdos matemáticos aprendidos destacamos o de resolu o de problemas envolvendo as quatro opera es. E de conhecimento pedagógico matemático ressaltamos o que se evidenciou em a es no grupo de estudos. Notamos como um trabalho diferenciado de forma o continuada em contexto, num grupo no qual atuamos como amigos críticos uns dos outros, influenciou e envolveu as integrantes.In this article we brought results from an investigation with elementary school teachers in a mathematics study group. This longitudinal two-year case study is characterized as a qualitative research with humanistic perspective. Our aim herein is to show some learning of two teachers in terms of mathematical knowledge and pedagogical mathematical knowledge generated from the dynamics of the study group. Data were collected in the weekly group meetings and during classes which the researchers observed or participated. In this group, the teachers respected each other, listened and were listened in their victories and anxieties, gave opinion, proposed ideas and contributed for the construction of different knowledge. This behavior influenced the teachers’ learning and attitudes towards mathematics, and this resonated in their classroom practices. We got evidences of improvement and learning of two sorts of knowledge: of mathematics content and of pedagogical mathematics. From the mathematical content knowledge learned we highlight problem solving involving the four operations. And from the pedagogical mathematical knowledge we highlight what was evidence
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