999 resultados para Mineral trióxido agregado


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A better understanding of the differential growth of upland rice (Oryza sativa L.) cultivars with increasing soil S availability could help improve rice yield under upland conditions. The objective of this study was to evaluate root and shoot growth and nutrition of upland traditional and modern rice cultivars as affected by S availability. The experimental design was completely randomized in a 3 (rates of S) × 3 (cultivars) factorial with four replications. Low availability of S in the soil reduces root and shoot development and the efficiency of N, P, and S uptake, as well as the concentration and content of these nutrients in rice cultivars. At 0 mg dm-3 of S, rice cultivars prioritize root growth over shoots, and the traditional cultivar does so with greater intensity. Our results suggested that more development of traditional cultivars under low S availability facilitates its adaptation in soils under this condition. On the other hand, the intermediate and modern cultivars are more responsive to S fertilization. Moreover, S fertilization allows significant increases in upland rice growth and must be considered in cropping systems aiming for high yields. © Soil Science Society of America.

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The organic production is a system that allows achieving good levels of productivity, while avoiding the risks of chemical contamination of farmers, consumers and the environment. Because jambu plant is widely used as alternative medicine and cosmetics industries, has been increasing interest in its cultivation. The aim of this study was to analyze the biomass, accumulation of nutrient, productivity and determine the pesticide residue in plant jambu when grown under organic and mineral fertilization. The experiment was conducted at the Experimental Farm São Manuel, FCA / UNESP. The experiment was conducted at São Manuel Experimental Farm UNESP. The statistical was arranged in the randomized block design, in a 2 x 6 factorial scheme, two sources of fertilizers (organic and mineral) and six doses of nitrogen, with four replications. The characteristics evaluated were plant height, fresh and dry weight, nutrients of accumulation in shoots and productivity. Mineral fertilizer gave higher biomass, productivity and accumulation of N and K in relation to organic fertilizer used. It is recommended the dose of 90g m -2 of urea as appropriate to obtain these results. However the organic fertilization favored the accumulation of phosphorus in plants jambu in relation the mineral fertilizer, and the dose of 10 kg m-2 of cattle manure recommended to achieve this result in plants jambu. We did not detect the presence of phosphorous and carbamate on leaves of jambu under organic and mineral fertilization. However, we observed the presence of chlorine in the leaves used for the two fertilizations.

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Incluye Bibliografía

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Background: Among adults, obesity has been positively related to bone mineral density. However, recent findings have pointed out that abdominal obesity could be negatively related to bone density. The above mentioned relationship is not clear among pediatric populations. Therefore, this cross-sectional study analyzed the relationship between thickness of abdominal adipose tissue and bone mineral variables in sedentary obese children and adolescents.Methods: One hundred and seventy five obese children and adolescents (83 male and 92 female) with ages ranging from 6 to 16 years-old were analyzed. Bone mineral content and density were estimated by dual-energy X-ray absorptiometry and ultrasound equipment which estimated the thickness of the abdominal adipose tissue. Pubertal stage was self-reported by the participants.Results: The mean age was 11.1 (SD = 2.6). Thickness of the abdominal adipose tissue was negatively related to bone mineral density (r = -0.17 [r95%CI: -0.03;-0.32]), independent of gender, pubertal stage and other confounders (β = -0.134 ± 0.042 [β95%CI: -0.217; -0.050]).Conclusions: In sedentary obese children and adolescents abdominal obesity is negatively related to bone mineral density, suggesting a potential link between abdominal obesity and osteoporosis. © 2013 Júnior et al.; licensee BioMed Central Ltd.

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Potassium, like nitrogen, it constitutes an essential element for growth, development and production of cotton crops. Moreover, these elements are directly related to fiber formation and when provided in suitable doses, influences its quality. The aim of the experiments was to evaluate the influence of potassium on biometric parameters, yield and quality of cotton fibers. For this purpose, plants of the cultivar Delta opal were grown in a greenhouse with altered potassium fertilization, simulating K deficiency and two overdoses. During the different phenological stages, biometric variables were analyzed including the production of fibers and their qualitative parameters. The sub-dose and the overdoses treatments of K, changed all the evaluated parameters, demonstrating the importance of potassium fertilizer on them.

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Objectives: To evaluate the influence on osseointegration of Deproteinized bovine bone mineral (DBBM) particles used to fill defects of at least 1 mm around implants having no primary contact with bone. Material and methods: Premolars and first molars were extracted bilaterally from the mandible of six Labrador dogs. After 3 months of healing, mucoperiosteal full-thickness flaps were elevated, and one recipient site was prepared in the molar region of each hemi-mandible to place implants. These were installed with a deliberate circumferential and periapical space to the bone walls of 1.2 mm. All implants were stabilized with passive fixation plates to maintain the implants in situ and without any contact with the implant bed. The control sites were left to be filled with coagulum, while at the test sites, the residual gap was filled with DBBM. After 3 months of submerged healing, the animals were sacrificed. Ground sections were prepared and analyzed histomorphometrically. Results: Mineralized bone-to-implant contact was 4.0% and 3.9% for control and test sites, respectively. The width of the residual defects was 0.48 mm and 0.88 mm at the control and test sites, respectively. The percentage of implant surface covered by a layer of dense connective tissue of 0.12 mm of width on average was 84.9% and 88.5% at the control and test sites, respectively. Conclusion: A minor and not predictable degree of contact or distance osteogenesis was obtained on the implant surface when primary contact of the implant surface with the implant bed had deliberately been avoided. DBBM grafting of the artificial gap did not favor osseointegration. Neither did it enhance the ability to bridge the gap with newly formed bone in an artificial defect wider than 1 mm. © 2013 John Wiley & Sons A/S.

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Quantitative variations in heterotrophic plate count (HPC) and in the presence of indicator microorganisms in 0.5, 1.5 and 20-L bottles of different brands of Brazilian mineral water were analyzed during their shelf life. No variations were identified in the presence of indicator microorganisms, but quantitative variations in HPC were observed in some brands, which suggests that changes may be occurring in the water quality during storage. The aim of this study was also to evaluate the quality of the bottled mineral waters and the presence of enterococci and Pseudomonas aeruginosa were verified in six and two bottles, respectively, which is in disagreement with the microbiological quality criteria established in the current legislation. Although no limit is set for HPC in mineral water, this study relies on the limit of 500 colony-forming units per mL of sample (CFU/mL). Seventy-two bottles presented levels above 500 CFU/mL and up to 560,000 CFU/mL. This study showed that the control of HPC (<500 CFU/mL) for non-returnable packaging seems to be adequate to ensure the quality of mineral water during storage. The high values of HPC and its variations detected during storage seem to fully justify the need for a reevaluation of the use of HPC in bottled mineral water quality management. More detailed studies on the potential health risk of HPC and its variations in mineral water are also needed. © 2012 Elsevier Ltd.

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Background & Study Aim: Physical activity has been an important factor to increase bone mineral density (BMD) and, consequently, to prevent and treat osteoporosis. The study aimed the effects of adapted Judo training on BMD in postmenopausal women, during pharmacological treatment. Material & Methods: Eighteen female volunteers participated in this study. They were separated into two groups: Adapted Judo training (AJT) (n=11; 52.2±5.3 years) and control group (CG) (n=7; 53.8±4.4 years). Lunar GE Dual Energy X-Ray Absorptiometry (DXA) measured BMD at lumbar L2-L4, femoral neck and trochanter sites. The training period for AJT was two years, comprised 12 mesocycles with different intensities. ANOVA compared 2 groups in 3 moments of testing and Scheffé Test allowed multiple comparisons between groups for the L2-L4 and femoral neck sites, but at trochanter was Fisher LSD. Results: ANOVA showed significant differences in the AJT group (F(2, 32)=15.187, p=0.000023). Scheffé Test showed significant increase on lumbar BMD after one year of AJT (Δ%=+8.9%, p=0.000017) and after two years this improvement stand still (p=0.33). The CG after one year presented significant decrease in BMD of femoral neck (Δ%=-6.9%, p=0.03) and trochanter (Δ%=-3.7%, p=0.0084). However, the CG recovered the loss of BMD of femoral neck (Δ%=+7.6%, p=0.02) and trochanter (Δ%=+3.8%, p=0.0079) after two years of study. Conclusions: Drug therapy, without the physical activity practice, can aid the maintenance of BMD. AJT may be considered as an efficient physical activity for postmenopausal women with low BMD in pharmacological treatment. © ARCHIVES OF BUDO | SCIENCE OF MARTIAL ARTS.

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Silicon can alleviate biotic and abiotic stresses in several crops, and it has beneficial effects on plants under nonstressed conditions. However, there is still doubt about foliar-applied Si efficiency and Si effects on mineral nutrition, physiological processes, and growth of potato (Solanum tuberosum L.) plants under wellwatered conditions. The objective of this study was to evaluate the effect of soil and foliar application of soluble Si on Si accumulation, nutrients, and pigments concentration as well as gas exchange and growth of potato plants. The experiment was conducted under greenhouse conditions in pots containing 35 dm3 of a Typic Acrortox soil. The treatments consisted of a control (no Si application), soil application of soluble Si (50 mg dm-3 Si), and foliar application of soluble Si (three sprays of 1.425 mM Si water solution, prepared with a soluble concentrate stabilized silicic acid), with eight replications. Both soil and foliar application of Si resulted in higher Si accumulation in the whole plant. Foliar application of Si resulted in the greatest Si concentration in leaves, and soil application increased Si concentration in leaves, stems, and roots. Silicon application, regardless of the application method, increased leaf area, specific leaf area, and pigment concentration (chlorophyll a and carotenoids) as well as photosynthesis and transpiration rates of wellwatered potato plants. However, only soil application increased P concentration in leaves and dry weight of leaves and stems. © Crop Science Society of America.

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Correspondence Analysis was adopted as tool for investigating the statistical structure of hydrochemical and weathering datasets of groundwater samples, with the main purpose of identifying impacts on mineral weathering caused by anthropogenic activities, namely fertilizing of farmlands. The hydrochemical dataset comprised measured concentrations of major inorganic compounds dissolved in groundwater, namely bicarbonate, silica (usually by-products of chemical weathering), chloride, sulphate and nitrate (typically atmospheric plus anthropogenic inputs). The weathering dataset consisted of calculated mass transfers of minerals being dissolved in loess sediments of a region located in SW Hungary (Szigetvár area), namely Na-plagioclase, calcite and dolomite, and of pollution-related concentrations of sodium, magnesium and calcium. A first run of Correspondence Analysis described groundwater composition in the study area as a system of triple influence, where spots of domestic effluents-dominated chemistries are surrounded by areas with agriculture-dominated chemistries, both imprinted over large regions of weathering dominated chemistries. A second run revealed that nitrification of N-fertilizers is promoting mineral weathering by the nitric acid reaction (anthropogenic pathway), in concurrence with the retreating of weathering by carbonic acid (natural pathway). It also indicated that dolomite and calcite are being players in a dedolomitization process driven by dissolution of gypsum fertilizers and nitrification of N-fertilizers. © 2013 Elsevier Ltd.

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There is a relative lack of technical studies on the adequate management of organic wastes from food processing. The aim of this study was to evaluate the effect of applying doses of a byproduct from guava processing, in the presence and absence of mineral fertilization, on the fertility of a an Ultisol (or Red-Yellow Argisol) under laboratory conditions. An entirely randomized 5x2 factorial experimental design was used with five byproduct doses, in the presence and absence of mineral fertilization, with four repetitions, for a total of 40 experimental units. Under the experimental conditions, the attributes pH, OM, K, Mg, BS, T, V, B, Fe, Zn and S-SO42- were affected by the guava byproduct doses, as well as by the presence or absence of mineral fertilization. With the use of this fertilization, the variables OM, K, H+Al, T, Fe and Zn increased more as a function of byproduct dose than in the absence of fertilization. The results obtained demonstrate the potential of using this waste material in the cycling and supply of nutrients.

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The objective of this work was to evaluate the efficiency of superficial applicationof limestone and slag, and their effects on soil chemical attributes and on yield and mineral nutrition of soybean, maize, and Congo signal grass (Urochloa ruziziensis). The experiment was carried out in a Rhodic Hapludox under no tillage system. The treatments consisted of the use of limestone or slag (silicates of calcium and magnesium) to correct soilacidity, and of a control treatment without the use of soil correctives. Rates were calculated in order to raise soil base saturation up to 70%. Soybean was sown in November 2006and maize in December 2007. Congo signal grass was sown right after the harvests of soybean and maize, and it was cropped during the offseasons. Soil chemical attributes were evaluated at 6, 12, and 18 months after the application of the corrective materials. Slag isan efficient source for soil acidity correction, being able to raise the exchangeable base levels in the soil profile faster than lime. Both limestone and slag increase dry matter yield of Congo signal grass, and grain yield of soybean and maize. Slag is more effective in improving maize grain yield.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Agronomia (Agricultura) - FCA