997 resultados para 25-degrees-c


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The plants are subject to the conditions of multiple stresses, such as water and salt stress, which limit their development and their chances of survival. Aware of the factors that control seed germination can generate support for management strategies of weed species. The objective of this study was to evaluate the possible effects of water stress caused by PEG and NaCl solutions on germination of wild Raphanus raphanistrum and Senna obtusifolia seeds. The seeding was done with four repetitions of 50 seeds on moistened paper with solutions of polyethylene glycol (PEG 6000) and NaCl at osmotic potentials of 0.0, -0.2, -0.4 and -0.8 MPa. The germination test was conducted at 25 degrees C in the presence of light, evaluating the first test score to seven days after sowing, and weekly, germination (normal seedlings) until 35 days; it was also calculated the index germination rate. The results allowed the conclusion that water stress by PEG causes a greater reduction in force, speed of germination and accumulated germination of seeds of Raphanus raphanistrum and Senna obtusifolia seeds. The Senna obtusifolia was more tolerant to water stress.

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We demonstrate the efficacy of propofol (2,6-diisopropylphenol) as an anesthetic when administered to fish in an immersion bath and show the absence of genetic side effects following short-term exposure to the drug. All tested fish were anesthetized (as indicated by loss of posture and lack of response to physical stimulation), and both the comet assay (tail intensity) and the micronucleus assay revealed that propofol does not induce primary DNA damage or chromosome damage in the fish Nile Tilapia Oreochromis niloticus. Our results should be considered in light of our particular test conditions, including the water temperature (similar to 25 degrees C), the life stage and size of the fish, and the single exposure to the anesthetic. We suggest that propofol is a promising anesthetic in terms of its lack of genotoxic effects, at least in low dosages in adult Nile Tilapia.Received June 25, 2013; accepted October 15, 2013

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

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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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This paper presents results describing the physical, mechanical, and thermal properties (melt flow index - MFI and oxidative induction time - OIT) of high density polyethylene and poly (vinyl chloride) after weathering exposure (6, 12, 18, and 30 months). The materials exposed were geomembranes of two thicknesses: 1.0 and 2.0 mm (PVC) and 0.8 and 2.5 mm (HDPE). The climate parameters (average) obtained were 25 degrees C (temperature), 93 mm (precipitation), 66% (relative humidity), and 19 MJ/m(2). day (intensity of global radiation). Some results showed, for instance, that the behavior of the geomembranes changed after the exposures. A few minor variations in physical properties occurred. The density and thickness, for instance, varied 0.5-1.0% (average) for both the PVC and HDPE geomembranes. The mechanical properties changed as a function of the period of exposure. In general, some decreases were verified by the deformation of PVC. The samples became more rigid. In contrast, HDPE geomembranes became more ductile. Despite the variations in elasticity, some increases in deformability were verified. An MFI test showed some degradation in HDPE geomembranes. OIT tests revealed small values for both intact and exposed samples.

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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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The objective of this study was to compare the efficiency of washing and trimming broiler carcasses to reduce bacterial contamination. At the poste-visceration site, 100 broiler carcasses were collected during 4 visits to a slaughterhouse in Santa Catarina State, Brazil. Birds were from the same flock, age, and approximately 2.4 kg of weight. Groups were as follows: group 1, with fecal contamination; group 2, without fecal contamination; group 3, with fecal contamination and trimmed; group 4, with fecal contamination and washed; group 5, with fecal contamination, and washed and trimmed. Carcass washings were performed with at least 1.5 L/bird of potable water (0.5 to 1 mg/kg of residual chlorine) at room temperature (20-25 degrees C) using spray cabinets with 44 spray nozzles distributed into 2 chambers (pressure of 2 kgf/cm(2) and 4 kgf/cm(2)). Washed carcasses (trimmed or not) showed significantly (P < 0.05) lower counts of aerobic mesophiles (plate count agar) on the third evaluation, and even lower (P < 0.01) counts for total coliforms (CT) and fecal coliforms (Escherichia coli). Trimmed carcasses showed significantly lower counts (P < 0.05) for plate count agar; however, we observed higher counts for E. coli (P < 0.05). The association of both treatments (washing and trimming) showed significantly higher (P < 0.05) counts for coliforms (CT and E. coli). We can conclude that the washing method is overall more efficient than the trimming method to decontaminate chicken carcasses at the postevisceration site. Hopefully, our findings can help poultry companies to minimize production costs by applying the washing method for carcass decontamination.

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The use of seeds of B. brizantha has increased, however, the physiological quality of seeds available to the producer is still a limiting factor for a good performance culture. The objective of this study was to evaluate the effects caused by chemical scarification, different periods of aging and priming on physiological quality and overcoming seed dormancy B. brizantha cv. MG-5 Victory. The seeds were subjected to chemical scarification-H2SO4 ( presence and absence), artificial aging periods ( zero, 24, 48, 72, 96, 120, 144 and 168 hours) at 41 degrees C and priming using the 0,2 KNO3 % ( presence and absence) for two hours at 25 degrees C, creating a completely randomized design in factorial 2x8x2, with four repetitions. The seeds were evaluated by testing germination and vigor. Chemical scarification is an effective method for breaking dormancy, but decreases the physiological seed. Overcoming seed dormancy B. brizantha occurs with the use of artificial aging for non-scarified and scarified seeds. Priming generally has no effect on the physiological quality and overcoming seed dormancy B. brizantha, however, it provides less loss of cellular constituents.

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Seed storage under controlled environmental conditions represents one of the most important lines of research to be applied on short-lived forest species as Handroanthus. The present research aimed to identify the most suitable seed storage conditions and longevity behavior of Handroanthus umbellatus seeds subject to the following storage treatments: packaging permeable paper bags under a no-controlled laboratory temperature and humidity (control) and multiwall semipermeable bag at temperatures of -18 degrees C ,1 degrees C and 25 degrees C. Seeds were dried to 6.3% of water content. Stored seeds were evaluated every three months until 24 months for water content, germination percentage and vigor utilizing first counting test. Seeds of T. umbellata are orthodox, with low longevity under natural conditions, once they remain viable for less than 5 months. The best conditions of seed preservation of these species were obtained by storage at -18 degrees C in multiwall bags. Under these conditions physiological seed quality remains unchanged for a 24-month period.