132 resultados para Boletines físicos


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The goal of this paper was to select among the attributes surveyed soil, one with better representation to explain the variability of the technological components of sugar cane. The study was conducted at ETH Eldorado Plant in Rio Brilhante, MS, in the agricultural year 2011/2012, in a Oxisol, which was installed a geostatistical grid for data collection of soil and plant, with 80 sampling points, a 80 ha area. From the standpoint of linear and spatial TCH has been explained as a function of volumetric moisture. The volumetric moisture collected at a depth of 0.00 to 0.20 m, which had values between 0,24 to 0,270 m(3) m(-3), resulted in sites with the highest productivity of sugar cane per hectare from 64 to 70 t ha(-1). To aid future studies aimed at precision agriculture, which will use the same attributes as those of the future works, the values of ranges of spatial dependence to be used should be between 81 and 487 meters.

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In the seeds of pioneer plants, the application of treatments for breaking dormancy, and selection by colour and size, are strategies for obtaining seeds of less dormancy and better germination performance. The aim of this study was to evaluate the effect of the physical and physiological aspects of seeds of the tall fringe-rush (Fimbristylis dichotoma) on germination and dormancy. To do this, the seeds were submitted to the following treatments in three studies: (i) control, immersion in H2SO4 (98%, 36N) for 1 minute, immersion in KNO3 (1, 2 and 3%) for 15 minutes, seeding on a substrate moistened with KNO3 (0.2%) and exposure for 5 and 10 hours in a forced air circulation oven at 40 and 70 degrees C; (ii) classification of the seeds by colour (light and dark) and application of the following treatments: control, immersion of the seeds in H2SO4 (98%, 36N) for 1 and 2 minutes, immersion in KNO3 (5% and 10%) for 15 and 30 minutes and seeding on a substrate moistened with KNO3 (0.2%); (iii) classification by size (0.60, 0.50 and 0.40 mm) and germination on a substrate moistened with KNO3 (0.2%) or distilled H2O. The seeds were evaluated by germination test, first count and germination speed index. Moistening the substrate with KNO3 (0.2%), and heat treatment at 40 degrees C for 10 hours improve performance in seeds of the tall fringe-rush. Light-coloured seeds do not display dormancy. Medium-sized seeds of the tall fringe-rush show better performance in terms of percentage and speed of germination.

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

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A avaliação dos atributos químicos e físicos do solo é necessária em estudos que exploram intensivamente os sistemas de pastejo. No presente trabalho, objetivou-se avaliar as variações nos atributos físicos e químicos de um Argissolo cultivado com capim-milênio, sob pastejo, no intervalo compreendido entre outubro/2001 e maio/2002, no quinto ano de aplicação sucessiva das seguintes doses de N: 0, 150, 300 e 450 kg ha-1. Após os cinco anos de aplicação de 450 kg ha-1 de N, o teor de MO aumentou em 5 g dm-3, o que resultou em aumento da CTC. No período de outubro/2001 a maio/2002 houve diminuição nos valores de pH e de V com a aplicação de N. A densidade do solo variou pouco com a adubação nitrogenada; a percentagem de microporos aumentou e a de macroporos diminuiu na camada de 0-5 cm com o aumento das doses de N, mas a porosidade total permaneceu constante; e a resistência à penetração, quando o solo apresentava 90 g kg-1 de água, não foi afetada pelas doses de N e não foi restritiva ao crescimento das plantas.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In this paper, we analyze the educational importance of teaching Physics in the early grades of elementary school from a teaching experience with students of 5th grade, using five experiments on electricity and magnetism. The theoretical framework used was the socio-historical psychology, especially Vigotski's studies on concept formation. It can be stated that the teaching of Physics and the use of experimental activities in the early grades cannot be simply associated to the teaching of certain scientific concepts, but should be explored bearing in mind the child's development.

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According to Statistical Yearbook of Social Security (2011), the number of accidents at work recorded in the agricultural sector is quite high, in the year 2010 there are records of thirty-four thousand nine hundred and ninetysix accidents, and in the year of 2011 there were thirty-one thousand and ninety-six accidents in the industry. Among so many diseases and accidents at work hearing loss is one of them. According to the Pan American Health Organization (2011) the Occupational hearing loss is then jury to the worker's health, often in the workplace. Mechanical vibrations are also present in many human activities exposing employees to an extremely aggressive agent. The combined action of these two factors can cause damage to the health of the worker, in this way, noise and vibration are the two major occupational agents present in the brush cutter operator activity. In the case there is another risk factor, the open work, which exposes the employee to the Sun’s rays and the high temperature indices. Studies have shown that: noise exceeds 115 dB (A) vibration 4.0 m/s2 and thermal stress of 29.9 o C. Ergonomic evaluations also demonstrated that the activity cause injury to workers.

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Modern society is characterized by the advance of technologies, the emergence and constant development of the technological field is responsible for a series of population adjustments, that being practically molded and daily transformed by media, which usually has the power of manipulating opinions and public approaches in every capacity and extensions of our lives, being a significantly and important tool, which most part of individuals in contemporary society can't work and live without, therefore most part of individuals depend on the use of many technological means, including social means, which have great relationship with the development and emergence of many psychological problems that completely impact on the social life of affected individuals, thus Physical Education is an area with the goal of verifying the level of influence that media reflects on the lifestyle choice to be followed and the relation of this influence with the presence and development of a series of psychological disorders that affect directly the health of those individuals. It has been gathered data about the subject according to scientific basis, more specifically, on Academic Google, Scielo and Pubmed, where it has been researched scientific articles that could contribute with the data and information to complete the text. The psychology of sports is an area of studies and knowledge that investigates and develops insight about these questions, making available scientifically tested and proven materials that supports the P.E. professional, that is connected in the practical field to visualize possible chained symptoms of these psychopathologies according to the development of these psychic disorders, that are usually common in current days, more precisely, disorders such as Anorexia, Vigorexia, self-dependence to physical exercise and selfcorporal dissapproval. It's vital to have total attention with the possibility of evolution of this psychopatology...

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Marchantia polymorpha develops under environmental conditions of high relative humidity and shading. As this habitat is the usually used in nurseries for the growth of seedlings of native tree species that species grows very quickly among developing tree seedlings and causes severe losses. This study was undertaken viewing more efficient either physical or chemical methods for the control of M. polymorpha. Two experiments were conducted under greenhouse conditions. In the first acetic acid (10, 20, and 40% of concentration), oxygenated water (50 and 100%) and the herbicides glyphosate (1,680 g AI ha) and fomesafen (375 g AI ha-1 ) were applied to the seedlings. In the second, the treatments consisted of soil previously submitted to a temperature of 105 °C for 48 hours, soil submitted to solarization in black plastic and in transparent plastic bags for 30 days, preemergence application of diuron (1,750 g AI ha-1 ) and trifluralina (1,575 g AI ha-1 ). The visual evaluations of the methods were performed 7, 14, 21, and 28 days after the application (DAA) and at 60 and 120 DAA, respectively, for the first and the second experiment. Only diuron and trifluralina resulted in a 100% control of M. polymorpha 120 DAA.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)