HETE-2 Observations of the X-Ray Flash XRF 040916

A long X-ray flash was detected and localized by the instruments aboard the High Energy Transient Explorer II (HETE-2) at 00:03:30 UT on 2004 September 16. The position was reported to the GRB Coordinates Network (GCN) approximately 2 hours after the burst. This burst consists of two peaks separated by 200 s, with durations of 110 s and 60 s. We have analyzed the energy spectra of the 1st and 2nd peaks observed with the Wide Field X-Ray Monitor (WXM) and the French Gamma Telescope (FREGATE). We discuss the origin of the 2nd peak in terms of flux variabilities and timescales. We find that it is most likely part of the prompt emission, and is explained by the long-acting engine model. This feature is similar to some bright X-ray flares detected in the early afterglow phase of bursts observed by the Swift satellite.Comment: 9 pages, 4 figures, Accepted for publication in PAS

Teores de nutrientes da folha bandeira e grãos de aveia-preta em função da adubação fosfatada e postássica

The black oat (Avena strigosa Schreber) has been commonly used as green manure, in crop rotation systems under no-tillage, fall-winter crop, and for cattle grazing, hay, and silage. The objective of this work was to evaluate the nutrient concentrations in the flag leaf and grains of black-oat affect by phosphate and potassium fertilization. The experiment was carried Out under field conditions on a Rhodic Nitosol, in Botucatu, São Paulo State, Brazil. Three doses of single superphosphate (0, 40 and 80 kg.ha(-1) of P(2)O(5)) and three of potassium chloride (0, 20 and 40 kg ha(-1) of K(2)O) were tested as a factorial (3 x 3), in a randomized complete block design, with four replicates. The fertilizers were applied in the sowing row. Ammonium sulphate was supplied for all plots (20 kg ha(-1) of N applied at sowing and 30 kg.ha(-1) after tillering stage). The concentrations of Ca, Mg, S, Fe, Mn, Cu and Zn in the flag leaf and the P and K concentrations in the grain were increased by phosphate fertilizer application. The potassic fertilization had no effect on the concentrations of nutrients in the flag leaf and grains of black-oat

Nutrients concentrations in the flag leaf and grains of black-oat affected by phosphate and potassium fertilization

The black oat (Avena strigosa Schreber) has been commonly used as green manure, in crop rotation systems under no-tillage, fall-winter crop, and for cattle grazing, hay, and silage. The objective of this work was to evaluate the nutrient concentrations in the flag leaf and grains of black-oat affect by phosphate and potassium fertilization. The experiment was carried Out under field conditions on a Rhodic Nitosol, in Botucatu, São Paulo State, Brazil. Three doses of single superphosphate (0, 40 and 80 kg.ha(-1) of P(2)O(5)) and three of potassium chloride (0, 20 and 40 kg ha(-1) of K(2)O) were tested as a factorial (3 x 3), in a randomized complete block design, with four replicates. The fertilizers were applied in the sowing row. Ammonium sulphate was supplied for all plots (20 kg ha(-1) of N applied at sowing and 30 kg.ha(-1) after tillering stage). The concentrations of Ca, Mg, S, Fe, Mn, Cu and Zn in the flag leaf and the P and K concentrations in the grain were increased by phosphate fertilizer application. The potassic fertilization had no effect on the concentrations of nutrients in the flag leaf and grains of black-oat

Qualidade fisiológica e armazenamento de sementes de milheto em função da época de semeadura

Pearl millet is recommended to produce dry matter for no-tillage system, as forage or for grain yield. The sowing time affects the crop development; thus, it can affect seed quality and initial storage conditions. The present research had as objective to evaluate the effects of sowing time on pearl millet seeds quality during the storage. Pearl millet seeds from twelve monthly sowing times were stored in environmental conditions, with no temperature and relative humidity control, and evaluated by seed moisture content, germination and vigor (first count of the germination test and electrical conductivity) for 0, 27 and 42 months of storage. The completely random design was employed, as a factorial experiment 12 x 3 (sowing time x storage time), with four replications. Means were compared by Tukey test (p <= 0.05). Pearl millet seeds produced in September resulted in the production of seeds with high germination and vigor, evaluated by the electrical conductivity test. The capacity of quality conservation of pearl millet seeds, for different storage times, is related to crop sowing time.O milheto é uma planta recomendada para a produção de palha e cobertura do solo no sistema de plantio direto, como forrageira ou para produção de grãos. A época de semeadura afeta o desenvolvimento da cultura; portanto, pode alterar a qualidade das sementes produzidas, influenciando nas condições iniciais de armazenamento. O presente trabalho objetivou avaliar os efeitos da época de semeadura na qualidade fisiológica de sementes de milheto durante o armazenamento. Sementes de milheto provenientes de doze épocas de semeadura, com intervalos mensais, foram armazenadas em condições de ambiente, e avaliadas mediante a determinação do teor de água, da germinação e do vigor (primeira contagem do teste de germinação e condutividade elétrica), aos 0, 27 e 42 meses. O delineamento experimental inteiramente casualizado foi utilizado, com quatro repetições, em esquema fatorial 12x3 (época de semeadura x período de armazenamento). As médias foram comparadas por meio do teste de Tukey a 5% de probabilidade. A semeadura do milheto em setembro resultou na produção de sementes de elevada germinação e vigor, avaliado pelo teste de condutividade elétrica. A capacidade de conservação da qualidade de sementes de milheto por diferentes períodos de armazenamento está relacionada à época de semeadura da cultura

Pré-condicionamento das sementes de mamoneira para o teste de tetrazólio

Preconditioning of castor bean seeds for the tetrazolium test. This research had the objective of standardizing the methodology for preconditioning of castor bean (Ricinus communis L.) seeds for the evaluation of their physiological potential by the tetrazolium test. The evaluated seed preconditioning methods were: seeds with coat between moist paper towel at 30, 35 and 40 degrees C for 6, 8, 10, 12, 14, 16 and 18 hours; and seeds without coat between moist paper towel; and seeds with coat immersed in water, at 25, 30, 35 and 40 degrees C for 1, 2, 3, 4, 5 and 6 hours. After preconditioning, the seed coat was removed, the seeds were cut lengthwise, and immersed in tetrazolium solution at a concentration of 0.2% for 120 minutes at 35 degrees C. The seeds' germination percentage, moisture content before and after preconditioning, and staining uniformity after the tetrazolium were evaluated. The statistical design was completely randomized, and the means comparisons were accomplished by the Tukey test at 0.05 level of probability. It was concluded that castor bean seeds should be preconditioned with coat between moist paper towel at 35 degrees C for 12 hours, so that the results of the tetrazolium test will be similar to those obtained in the germination test

Adubação fosfatada, produção e qualidade de sementes de populações de amendoim

The objective of this work was to evaluate the response of groundnut (Arachis hypogaea L.) to different doses of phosphate fertilization (0, 40, 80 and 120 kg/ha of P 2O 5) for yield and quality of seeds. Triple-superphosphate (45% of P 2O 5 and 15% of CaO) was used. The groundnut genotypes were: Tatu, Oirã, Tupã, FCA 170 and FCA 265. The dose of 40 kg/ha of P 2O 5 exerced positive influence on yield and quality of seeds. The genotypes showed similar behaviour as for seed production and germination for all doses of phosphorus with interaction between genotypes and P doses as for 100 seeds weight and seed vigor. The dose of 40 kg/ha of P 2O 5 is enough for good production and quality of groundnut.O objetivo do presente trabalho foi avaliar a resposta do amendoim (Arachis hypogaea L.) a diferentes doses de adubo fosfatado (0, 40, 80 e 120 kg/ha de P2O5), com vistas à produção e qualidade de sementes. Usou-se superfosfato triplo (45% P2O5 e 15% CaO). As populações de amendoim foram: Tatu, Oirã, Tupã, FCA 170 e FCA 265. A dose de 40 kg/ha de P2O5 exerceu influência positiva na produção e qualidade das sementes. As populações de amendoim apresentaram comportamento assemelhado quanto à produção de sementes e sua germinação, em todas as doses de P, mas com interações entre genótipos e doses de P no peso de 100 sementes e no vigor das sementes. A dose de 40 kg/ha de P2O5 é suficiente para boa produção e qualidade do amendoim.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Métodos de superação de dormência de sementes de barbatimão

The aim of this research was to identify methods for breaking dormancy and promoting germination of Stryphnodendron adstringens and S. polyphyllum seeds. Seeds of both species were submitted to the following treatments for breaking dormancy: control; mechanical scarification (sandpaper number 220); hot water (initial temperature of 87 degrees C) for 5 and 15 minutes; chemical scarification with H(2)SO(4) (95%) for 30, 45, 60, 75, 90 and 105 minutes; thermal shock 1 (0 degrees C and 50% RH for 1 h and thereafter 10 minutes into water Ti=85 degrees C, Tf=57 degrees C); thermic shock 2 (40 degrees C and 40% RH for 6 h and thereafter 10 minutes into water, Ti=0 degrees C, Tf=3 degrees C); thermal shock 3 (40 degrees C and 40% RH for 6h and thereafter 10 minutes into water, Ti=25 degrees C, Tf=25 degrees C). We concluded that seeds belonging to same genus but from different species answered differently to some treatments for breaking dormancy. Chemical scarification with H(2)SO(4) (45 minutes) and mechanical scarification with sandpaper are methods that can be employed with efficiency to break dormancy and promote germination for both species

Consorciação e plantas daninhas afetando a produtividade e a qualidade de sementes de sorgo

This research aimed to study competition effects of legumes intercropping and weeds on seeds yield and quality of Sorghum bicolor (L.) Moench. The experiment was carried out in a Rhodic Nitisol, under field condition in Botucatu region, São Paulo State, Brazil. Ten treatments were tested: sorghum (cv. A-6304) intercropped with Dolichos lablab L., Mucuna aterrima (Piper et Tracy) Holland, Canavalia ensiformis D. C. or Crotalaria juncea L., that were sown in the same time of sorghum or 20 days after the sorghum sowing, and sorghum weed-free and sorghum without weeding. The experimental design employed was the completely randomized blocks with four replications. There were evaluated sorghum seeds yield and some characteristcs of seed quality: purity, hectolitric weight, 1000 seeds weight, insect infestation, germination and vigor (by first counting of germination test and accelerated ageing test). The competition caused by legumes intercropping and weeds affected the yield and the physical and physiological characteristics of sorghum seeds, but the intensity of prejudicial effects depended on the time and the species of legume intercropping.O trabalho teve por objetivo estudar os efeitos da competição, ocasionada por leguminosas em consórcio, estabelecido em duas épocas, e pelas plantas daninhas, sobre a produtividade e qualidade de sementes de sorgo. O experimento foi conduzido em Nitossolo Vermelho, em condições de campo, em Botucatu – SP. Constou de dez tratamentos, constituídos pela consorciação de sorgo granífero (cv. A-6304) com labe-labe, mucuna-preta, feijão-de-porco ou crotalária, semeados simultaneamente ou 20 dias após o sorgo, e os tratamentos sorgo no limpo e sorgo no mato (com plantas daninhas), em delineamento experimental de blocos casualizados, com quatro repetições. No sorgo foram avaliadas a produtividade e características de qualidade das sementes: pureza física, peso hectolítrico, massa de 1000 sementes, sementes infestadas, germinação e vigor (pela primeira contagem do teste de germinação e pelo teste de envelhecimento acelerado). A competição das leguminosas em consórcio e das plantas daninhas afetou a produtividade e as características físicas e fisiológicas das sementes de sorgo, com a intensidade do efeito prejudicial variando em função do momento de implantação da consorciação e da espécie consorciada