999 resultados para Production of Subjectivity


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The effect of stocking prawns Macrobrachium rosenbergii at increasing densities in ponds with Nile tilapia Oreochromis niloticus reared at low density was evaluated. Twelve 0.01-ha earthen ponds were stocked with 1 tilapia/m2 and 0, 2, 4, or 6 post-larvae prawn/m2. Three replicates were randomly assigned to each prawn density. Postlarval prawns were stocked a week prior to tilapia juveniles and both were harvested 175 d after the beginning of the experiment. Tilapia final average weight, survival, production, and food conversion rates did not differ significantly among treatments (P > 0.05); the averages were 531 g. 67%, 3,673 kg/ha, and 1.91, respectively. Prawn survival rates did not differ for the three stocking densities (mean 90%). However, final weight and production were significantly different (P < 0.05) as follows: 34.0, 23.0, and 14.7 g and 639, 909, and 818 kg/ha, respectively for 2, 4, and 6 prawns/m2 densities. Stocking densities up to 6 prawn/m2 did not affect tilapia production and required neither additional feeding nor significant changes in management. The polyculture system allowed an increase in total production with the same amount of supplied feed, thus improving the system sustainability.

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The production of chlorine and hypochlorite is of great economical and technological interest due to their large-scale use in many kinds of commercial applications. Yet, the current processes are not without problems such as inevitable side reactions and the high cost of production. This work reports the photoelectrocatalytic oxidation of chloride ions to free chlorine as it has been investigated by using titanium dioxide (TiO2) and several metal-doped titanium dioxide (M-TiO2) material electrodes. An average concentration of 800 mg L-1 of free chlorine was obtained in an open-air reactor using a TiO2 thin-film electrode biased at +1.0 V (SCE) and illuminated by UV light. The M-doped electrodes have performed poorly compared with the pure TiO2 counterpart. Test solutions containing 0.05 mol L-1 NaCl pH 2.0-4.0 were found to be the best conditions for fast production of free chlorine. A complete investigation of all parameters that influence the global process of chlorine production by the photoelectrocatalytic method such as applied potential, concentration of NaCl, pH solution, and time is presented in detail. In addition, photocurrent vs potential curves and the reaction order are also discussed.

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This study was carried out in January of two consecutive years. The objective was to evaluate the grazing time, the grazing rate and the milk production of crossbred cows, managed in two rotational grazing areas, one with elephant grass (Pennisetum purpureum Schum. cv. Guaçu) and another one with Tanzania grass (Panicum maximum Jacq. cv. Tanzania), both with natural shade in the rest area. The experiment was divided in two phases, the first with 12 cows that remained day and night in the paddock and were milked twice a day. In the second phase 15 cows were observed and remained 10.43 hours in the paddock during the day, and were kept in a corral during the night. Each cow was observed every 15 minutes. Grass specie had no effect on milk production in the two phases of the experiment. The grazing time was 564 and 474 minutes and the grazing rate was 28.7 and 24.4 minutes/hour for the Elephant grass and Tanzania grass, respectively, in first phase. In the second phase,the grazing time was 461 and 426 minutes and the grazing rate was 42.7 and 39.4 minutes/hour for the Elephant grass and Tanzania grass, respectively. Correlations were observed (P<0.01) between grazing rate and the minimum temperature (-0.68), the maximum temperature (-0.76), the relative humidity (0.44) and the THI (-0.76).

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GCTase production by a new strain of Bacillus alkalophillc CGII isolated from Brazilian wastewater of manioc flour industry was examined. The growth medium used was composed by 1.5% starch, 1.5% nitrogen and 1% Na 2CO3. Higher activity was obtained with starch, maltodextrin and galactose. When glucose was added to the medium, no enzyme production was observed. High enzyme activity and growth were reached when aeration was increased (88.6 U/mL). The enzyme characterization showed an optimum pH and temperature 8.0 and 55°C for starch hydrolyses, respectively. Mg+ and Ca++ showed small activation; however, Hg + and Cu+ showed a strong enzyme inhibition.

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Titanium and its alloys provide high strength-to-weight ratios, good fatigue strength and increased corrosion resistance compared with others materials. Its acceptance in aerospace has been limited by costs considerations such as high cost of raw material, high buy-to-fly ratios and expensive machining operations. Significant cost reductions can be obtained by vacuum sintering and powder metallurgy (P/M) techniques by producing near net shapes and consequently minimizing material waste and machining time. The Ti 35Nb alloy exhibit a low modulus of elasticity. Stemming from the unique combination of high strength, low modulus of elasticity and low density, this alloy is intrinsically more resistant to shock and explosion damages than most other engineering materials. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering between 900 and 1600 °C, in vacuum. Sintering behavior was studied by means of dilatometry. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Density was measured by Archimedes method. Copyright © 2004 Society of Automotive Engineers, Inc.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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A newly-isolated thermophilic strain of the zygomycete fungus Rhizomucor pusillus 13.36 produced highly active dextrinogenic and saccharogenic enzymes. Cassava pulp was a good alternative substrate for amylase production. Dextrinogenic and saccharogenic amylases exhibited optimum activities at a pH of 4.0-4.5 and 5.0 respectively and at a temperature of 75°C. The enzymes were highly thermostable, with no detectable loss of saccharogenic or dextrinogenic activity after 1 h and 6 h at 60°C, respectively. The saccharogenic activity was inhibited by Ca2+ while the dextrinogenic was indifferent to this ion. Both activities were inhibited by Fe2+ and Cu2+ Hydrolysis of soluble starch by the crude enzyme yielded 66% glucose, 19.5% maltose, 7.7% maltotriose and 6.6% oligosaccharides. Copyright © 2005, The Microbiological Society of Korea.

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Human monocytes lack fungicidal activity against high virulent strains of Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, even after IFN-γ activation. However, monocytes treated with indomethacin (INDO) or INDO plus IFN-γ effectively killed this fungus, suggesting an inhibitory role of prostaglandins in this process. Thus, the purpose of this work was to test if this regulatory effect of prostaglandin was associated with alterations on H2O2 production and/or on modulatory cytokines levels, such as TNF-α, IL-10, and IL-6. Peripheral blood monocytes obtained from 10 healthy donors were incubated for 18 hours in the presence or absence of IFN-γ, INDO, or IFN-γ plus INDO, and further challenged with a high virulent strain of P. brasiliensis (Pb18) for 4 hours. Then, the monocytes cultures were evaluated for H2O2 release and fungicidal activity calculated by counting the colony forming units after plating. Moreover, on supernatants of the same cultures, TNF-α, IL-10, IL-6, and PGE2 concentrations were evaluated by ELISA. Monocytes treated with INDO or INDO plus IFN-γ presented higher fungicidal activity associated with the release of higher levels of H2O2 and TNF-α, but lesser levels of PGE2, when compared to nontreated cells. However, the levels of IL-10 and IL-6 were similar between treated and nontreated cells. The results suggest that human monocytes when challenged with high virulent strains of P. brasiliensis produce prostaglandins that inhibit the fungicidal activity of these cells by reducing H2O2 and TNF-α levels.

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Several studies have been conducted in the last decades aiming to obtain an anti-canies vaccine, however some studies have demonstrated cross reactivity between Streptococcus mutans surface antigens and the human cardiac tissue. In this work, the reactivity of five anti-Streptococcus mutans monoclonal antibodies (MoAb) (24A, 56G, G8, E8 and F6) was tested against oral streptococci, cardiac antigens and skeletal and cardiac myosins, aiming to evaluate the specificity of these MoAb. The hybrid producers of immunoglobulins of the IgG 2b class were cloned by limit dilution and expanded in vivo. MoAb were tested by ELISA. The hybrid 24A reacted with S. mutans CCT 1910, S. salivarius CCT 0365 and S. pyogenes T23. No reactivity difference was observed among the tested species. Cross reactivity with heart and cardiac myosin was not confirmed and only reaction with myosin of skeletal muscle was observed (p = 0.0381). The hybrid 56G reacted with all the tested microorganisms and there was statistically significant difference between S. mutans and S. pyogenes T23 (p < 0.001). This hybrid also reacted with myosin of skeletal muscle (p = 0.0095). C8, E8 and F6 presented low reactivity against oral streptococci strains and no reactivity against cardiac antigens. The data of this study showed that the 24A and 56G anti-S. mutans MoAb presented reactivity with S. pyogenes and S. salivarius, reinforcing the occurrence of common antigens between these species. The tested MoAb presented low cross-reactivity with myosin of skeletal muscle, but anti-heart activity could not be confirmed.

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The aim of the work was to evaluate the performance of four cultivars of iceberg lettuce, in a greenhouse, with and without ground cover. The experimental design adopted was that of subdivided parcels, where parcels were provided with and without ground cover consisting of black polyethylene and the subparcels consisted of the cultivars. There were three repetitions per treatment and six central plants of each parcel were evaluated. Drip irrigation was utilized. The cultivars studied were: 'Laurel', 'AF-389', 'Mayara' and 'Tainá'. The seeds were planted in Styrofoam trays with 288 cells containing the substrate Plantmax Hortaliças® A. The trays were kept in a greenhouse until transplanting, 25 days after seeding. The parameters examined were: fresh weight of the aerial part per plant, longitudinal (DL) and transverse (DT) diameters of the head, height of the plant and mean number of leaves per plant. Only among the cultivars there were significant differences in transverse and longitudinal diameters of the head and height of the plant. No significant interactions were detected between ground cover and cultivars. With regard to longitudinal and transverse diameters, 'AF-839' (DL = 27.11 cm; DT = 24.53 cm) showed smaller diameters than those of 'Laurel' (DL = 31.13 cm; DT = 30.55 cm), but did not differ from the other cultivars. In regard to height of the plants, 'Laurel' (20.66 cm) had the greatest value and 'AF-839' (16.02 cm) the lowest. The cultivars did not differ with respect to mean number of leaves and fresh weight of the aerial part of the plant. It is concluded that there were no significant differences in the cultivation of the iceberg lettuce with and without ground cover. The cultivar 'Laurel' stood out with respect to longitudinal and transverse diameters and height of the plant, only differing from the 'AF-839' with regard to the diameters.

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This article investigates a strain of the yeast Aureobasidium pullulans for cellulase and hemicellulase production in solid state fermentation. Among the substrates analyzed, the wheat bran culture presented the highest enzymatic production (1.05 U/mL endoglucanase, 1.3 U/mL β-glucosidase, and 5.0 U/mL xylanase). Avicelase activity was not detected. The optimum pH and temperature for xylanase, endoglucanase and β-glucosidase were 5.0 and 50, 4.5 and 60, 4.0 and 75°C, respectively. These enzymes remained stable between a wide range of pH. The β-glucosidase was the most thermostable enzyme, remaining 100% active when incubated at 75°C for 1 h. © 2007 Humana Press Inc.

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There is a growing body of evidence that melatonin and its oxidation product, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), have anti-inflammatory properties. From a nutritional point of view, the discovery of melatonin in plant tissues emphasizes the importance of its relationship with plant peroxidases. Here we found that the pH of the reaction mixture has a profound influence in the reaction rate and products distribution when melatonin is oxidized by the plant enzyme horseradish peroxidase. At pH 5.5, 1 mm of melatonin was almost completely oxidized within 2 min, whereas only about 3% was consumed at pH 7.4. However, the relative yield of AFMK was higher in physiological pH. Radical-mediated oxidation products, including 2-hydroxymelatonin, a dimer of 2-hydroxymelatonin and O-demethylated dimer of melatonin account for the fast consumption of melatonin at pH 5.5. The higher production of AFMK at pH 7.4 was explained by the involvement of compound III of peroxidases as evidenced by spectral studies. On the other hand, the fast oxidative degradation at pH 5.5 was explained by the classic peroxidase cycle. © 2007 The Authors.

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