972 resultados para ore dressing


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Currently new techniques for data processing, such as neural networks, fuzzy logic and hybrid systems are used to develop predictive models of complex systems and to estimate the desired parameters. In this article the use of an adaptive neuro fuzzy inference system was investigated to estimate the productivity of wheat, using a database of combination of the following treatments: five N doses (0, 50, 100, 150 and 200 kg ha(-1)), three sources (Entec, ammonium sulfate and urea), two application times of N (at sowing or at side-dressing) and two wheat cultivars (IAC 370 and E21), that were evaluated during two years in Selviria, Mato Grosso do Sul, Brazil. Through the input and output data, the system of adaptive neuro fuzzy inference learns, and then can estimate a new value of wheat yield with different N doses. The productivity prediciton error of wheat in function of five N doses, using a neuro fuzzy system, was smaller than that one obtained with a quadratic approximation. The results show that the neuro fuzzy system is a viable prediction model for estimating the wheat yield in function of N doses.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The knowledge of the meat production from different buffalo breeds and their crossings in different feeding systems becomes necessary for the supply of subsidies to whole productive meat chain. Some quantitative carcass traits of Mediterranean buffaloes bulls, finished in feedlot, with initial age of fourteen months and 330 kg live weight, slaughtered with 450, 480, 510 and 540 kg, were evaluated. The diet contained 13% crude protein, 2.68 Mcal digestible energy/kg DM and a roughage : concentrate ratio of 25:75. Regression equations for prediction weight and yield of primal cuts of carcass as a function of slaughter weight were obtained. Carcass dressing percent increased as the slaughter weight increased (49.2; 49.5; 49.7; and 49.9%). The Pistola Style cut weight although increasing linearly in weight (108.2; 117.6; 124.0 and 130.7 kg) as the slaughter weight increased, declined linearly when expressed in relation to cold carcass weight (49.5; 49.0; 48.6 and 48.2%). In this experimental conditions Mediterranean young bulls slaughtered between 450 to 540 kg of live weight showed increasing yields of cold carcass, forequarter and thin flank.

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Aims: To compare the effectiveness of adding cyclobenzaprine, tizanidine, or placebo to patient education and a self-care management program for patients with myofascial pain and specifically presenting with jaw pain upon awakening. Methods: Forty-five patients with a diagnosis of myofascial pain based on the guidelines of the American Academy of Orofacial Pain participated in this 3-week study. The subjects were randomly assigned into one of three groups: placebo group, TZA group (tizanidine 4 mg), or CYC group (cyclobenzaprine 10 mg). Patients were evaluated for changes in pain intensity, frequency, and duration by using the modified Severity Symptoms Index and changes in sleep quality with the use of the Pittsburgh Sleep Quality Index. Data were analyzed by ANOVA and post-hoc or nonparametric statistical tests as appropriate. Results: All three groups had a reduction in pain symptoms and improvement of sleep quality based on a comparison of pretreatment and treatment scores. However, no significant differences among the groups were observed at the posttreatment evaluation. Conclusion: The use of tizanidine or cyclobenzaprine in addition to self-care management and patient education was not more effective than placebo for the management of patients with myofascial jaw pain upon awakening.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this research was to evaluate the effects of rates and sources of potassium in top dressing on yield of cabbage hybrid Kenzan. Two experiments were conducted (15/07 to 22/11/2010 and 28/09/2010 to 27/01/2011) and nine treatments, resulted from a factorial 4 rates (45; 90; 135 and 180 kg ha(-1) of K2O) x 2 sources (KCl and K2SO4) + 1 control (without K in top dressing) were evaluated at randomized block design, with 4 replicates. After the harvest, fresh and dry weight of cabbage head and of external leaves; leaf number (from cabbage and external); diameter and height of cabbage head were evaluated. It was evaluated soil chemical characteristics at the end of first experiment and content of macro and micronutrients in plants. It was observed that potassium rates and sources did not influence most of evaluated characteristics. K content in plant increased linearly with KCl application. Results obtained show that, probably, it is not necessary application of K in top dressing when base fertilization is done with this nutrient, besides existing recommendations for this crop.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Geophysical methods are widely used in mineral exploration. This paper discusses the results of geological and geophysical studies in supergene manganese deposits of southern Brazil. Mineralized zones as described in geological surveys were characterized as of low resistivity (20 Omega.m) and high chargeability (30ms), pattern found also in oxides and sulfite mineral deposits. Pseudo-3D modeling of geophysical data allowed mapping at several depths. A relationship between high chargeability and low resistivity may define a pattern for high grade gonditic manganese ore. Large areas of high chargeability and high resistivity may result in accumulation of manganese and iron hydroxides, due to weathering of the gonditic ore, dissolution, percolation and precipitation.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Este trabalho teve como objetivo avaliar características de carcaça por ultra-som de 28 bubalinos jovens Mediterrâneo terminados em confinamento e abatidos aos 450, 480, 510 e 540 kg de peso vivo (PV). Foi utilizado um equipamento de ultra-som Piemedical Scanner 200 Vet, com transdutor linear de 178 mm e 3,5 MHz, a cada intervalo de aproximadamente 28 dias, para obter a área do longíssímus dorsí (ALOU), espessura de gordura subcutânea (EGSU) entre a 12ª e 13ª costelas e a espessura de gordura na picanha (EGP8U), sob o terço superior do músculo bíceps femorís. Após atingirem os pesos de abate pré-estabelecidos, os animais foram abatidos e obteve-se o peso de carcaça quente (PCQ) e o rendimento de carcaça (RC). Após 24 horas de resfriamento, as carcaças foram seccionadas entre a 12a e 13a costelas e obtidas a área do longíssímus dorsí (ALOC), a espessura de gordura (EGSC) e a espessura de gordura sob o bíceps femorís (EGP8C) na carcaça. As correlações entre as medidas por ultra-som e na carcaça foram de 0,96 entre ALOU e ALOC, de 0,99 entre EGSU e EGSC e de 0,91 entre EGP8U e EGP8C. Equações de regressão utilizando o peso vivo (PV), ALOU, EGSU e EGP8U explicaram 95% da variação do PCQ quando a medida foi realizada imediatamente antes do abate. As equações para estimar o RC utilizando as mesmas características explicaram cerca de 32% da variação quando a medida foi realizada imediatamente antes do abate. O peso da porção comestível do corte traseiro a partir de medidas efetuadas por ultra-som e na carcaça é predito com maior magnitude que a percentagem da porção comestível. Os resultados indicam que as equações para as medidas ultra-sônicas apresentaram boa acurácia e podem ser utilizadas para estimar diferenças entre grupos de animais, mas há a necessidade de mais estudos envolvendo maior número de animais e de outros grupos genéticos de bubalinos.

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This work presents a new and simple electrode, which may be used to achieve the electrochemical response of ground solids or insoluble samples. Ore samples from Morro Velho Mine (Brazil) were employed to exemplify the use of such electrodes. The new electrode avoids the use of binders or other agents overcoming major deterioration problems. (C) 2002 Published by Elsevier Science B.V.

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The objective of this work was to evaluate the effects of silicon application adjusted with nitrogen fertilization via top-dressing on grain productivity, the silicon contents of the soil, in the plant tissue and nitrogen contents in dry and irrigated conditions. The experimental outlining was from designed blocks with subdivided parcels and four repetitions. The treatments consisted of culture system (dry and irrigated) and the under parcels by the combination of silicon (0 and 100 kg ha(-1)), in magnesium and calcium silicate form (with 23% of SiO2), and four doses of N (urea) via top-dressing (0, 30, 60 and 90 kg ha(-1)). Silicon application at sowing furrow was a viable technique because it provided significant increase in the content of this element in the root growth of rice. The application of silicon in the sowing furrow did not change the content of the element nor the nitrogen nutrition in rice plants. The nitrogen application reduced the silicon content and increased nitrogen nutrition in rice plants. Silicon application at sowing furrow provided no increase in rice grain yield. When there was no water limitation to nitrogen fertilization enhanced linearly on rice grain yield, whereas under water stress the effect of nitrogen fertilization was limited.

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The Cu-Au mine of Chapada is located in the municipality of Alto Horizonte, in the northwestern portion of Goiás state and is inserted in the geological context of the Brasilia Belt, specifically the Mara Rosa Magmatic Arc, which hosts important deposits of Au and Cu-Au. The rocks found in the study area belong mainly to the Volcano-Sedimentary Sequence of Mara Rosa and are composed of basic to acidic metavolcanic rocks, psammiticpellitic metasedimentary rocks, chemical rocks and also hydrothermal products. Late intrusions occur and are represented by pegmatitic dikes and tonalitic bodies. The ore deposit of the Chapada mine is formed predominantly by the chalcopyrite-pyritemagnetite association, where pyrite is the most abundant mineral. Through the structural mapping of the mining fronts, it was able to recognize three deformational phases (Dn, Dn +1, Dn +2). During the Dn phase, isoclinal recumbent folds were formed, in association with amphibolites facies metamorphism. Later, in phase Dn +1, there was formation of drag folds and intrafolial folds in association with retrograde metamorphism in the greenschist facies. The deformational phase Dn +2, in its turn, was responsible for late symmetrical folding of the foliation, with NS and EW axes, resulting in an interference pattern of the dome-and-basin type