Analytical attitude propagation with non-singular variables and gravity gradient torque for spin stabilized satellite

An analytical approach for the spin stabilized satellite attitude propagation is presented using the non-singular canonical variables to describe the rotational motion. Two sets of variables were introduced for Fukushima in 1994 by a canonical transformation and they are useful when the angle between z-satellite axis of a coordinate system fixed in artificial satellite and the rotational angular momentum vector is zero or when the angle between Z-equatorial axis and rotation angular momentum vector is zero. Analytical solutions for rotational motion equations and torque-free motion are discussed in terms of the elliptic functions and by the application of some simplification to get an approximated solution. These solutions are compared with a numerical solution and the results show a good agreement for many rotation periods. When the mean Hamiltonian associated with the gravity gradient torque is included, an analytical solution is obtained by the application of the successive approximations' method for the satellite in an elliptical orbit. These solutions show that the magnitude of the rotation angular moment is not affected by the gravity gradient torque but this torque causes linear and periodic variations in the angular variables, long and short periodic variations in Z-equatorial component of the rotation angular moment and short periodic variations in x-satellite component of the rotation angular moment. The goal of this analysis is to emphasize the geometrical and physical meaning of the non-singular variables and to validate the approximated analytical solution for the rotational motion without elliptic functions for a non-symmetrical satellite. The analysis can be applied for spin stabilized satellite and in this case the general solution and the approximated solution are coincidence. Then the results can be used in analysis of the space mission of the Brazilian Satellites. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

Effect of poultry viscera meal inclusion in broiler diets in different rearing periods on performance, carcass and parts yields

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Critical periods of weed control in naturally green colored cotton BRS Verde

Cotton with naturally colored fiber is increasing as a commercial crop due specially to its textile processing with reduced environmental impact, as dying is not necessary. The critical period of weed control and the weed community were studied in a field with the naturally green colored fiber cv. BRS Verde cultivated in Missao Velha, Brazil. Without weed control during all the cycle, a reduction of 82.9% in yield was observed. The critical period of weed control was between 31 and 74 days after emergence for a reduction of 5% in yield. The weed community was composed of 21 species, with higher relative importance and dominance of monocotyledonous species. The beginning of the critical period was found to be more influential on yield than the ending. Thus, defining the right moment to start weed control can be more important to yield than determining the moment to cease it. (C) 2011 Elsevier B.V. All rights reserved.

Modeling of weeds interference periods in bean

Objetivou-se com este trabalho determinar o período de convivência anterior à interferência das plantas daninhas (PAI) e o período anterior ao dano no rendimento econômico (PADRE) na cultura do feijão, em diferentes espaçamentos (0,45 e 0,60 m) e densidade de plantas (10 e 15 plantas m-1). Os tratamentos foram constituídos de períodos de convivência entre a cultura e as plantas daninhas (0 a 10, 0 a 20, 0 a 30, 0 a 40, 0 a 50, 0 a 60, 0 a 70 e 0 a 80 dias), mais uma testemunha sem convívio com as plantas daninhas. Adotou-se o delineamento experimental de blocos casualizados, com quatro repetições. Os períodos anteriores à interferência (PAI) da cultura foram de 23, 27, 13 e 19 dias após emergência, e os períodos anteriores ao dano no rendimento econômico (PADRE), de 10, 9, 8 e 8 dias, para os tratamentos com espaçamento de 0,45 m e densidades de semeadura de 10 e 15 plantas m-1 e para aqueles com espaçamento de 0,60 m e densidades de semeadura de 10 e 15 plantas m-1, respectivamente, o que reduziu a produtividade de grãos em 63, 50, 42 e 57%, respectivamente, com a presença das plantas daninhas durante todo o ciclo do feijoeiro.

Estimation of genetic parameters for partial egg production periods by means of random regression models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Physical-chemical analysis of the cerebrospinal fluid of healthy dogs submitted to different storage periods and temperatures

Disfunções envolvendo o sistema nervoso são de grande importância na Medicina Veterinária, pois tratam-se de enfermidades de elevada incidência e com poucos subsídios auxiliares no seu diagnóstico, prognóstico e na avaliação de terapias empregadas. Ainda hoje, o diagnóstico baseia-se, em grande parte, no histórico e no exame clínico neurológico. Dessa forma, a análise dos constituintes do fluido cefalorraquidiano torna-se uma das poucas alternativas de acesso clínico ao sistema nervoso central (SNC). Mesmo com a grande utilidade do exame físico-químico e citoscópico do liquor na neurologia veterinária, poucos são os estudos sobre a estabilidade dos seus constituintes sob estocagem. Dessa forma, o presente trabalho teve como finalidade verificar a influência da temperatura e do tempo de conservação nas características físico-químicas do liquor de cães hígidos. Para tanto, foram coletadas amostras de LCR, através da punção da cisterna cerebelo-medular de cães clinicamente sadios, as quais foram submetidas à análise da densidade específica, do pH, da glicorraquia, das proteínas totais e das atividades das enzimas creatina quinase (CK) e aspartato aminotransferase (AST), após conservá-las em diferentes temperaturas (25°C, 4°C e -4°C) e por diferentes períodos de tempo (logo após a colheita, 24 horas, 48 horas, uma semana e um mês). Dentre os resultados obtidos, foi possível verificar, principalmente, que houve estabilidade dos parâmetros estudados por até um mês de estocagem nas amostras mantidas sob a temperaturas de congelamento de -4°C.

Passionflower supplementation in diets of Japanese qualis at rearing and laying periods

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

Digestion of feed fractions and intake of heifers fed hydrolyzed sugarcane stored for different periods

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of Different Periods of Clomazone plus Hexazinona Permanence in Soil and Sugarcane Mulch before the Occurrence of Rain on Weed Control Efficacy

The objective of this work was to evaluate the efficacy of the formulated mixture clomazone and hexazinone applied in soil or combined with sugarcane mulch, after different periods of permanence without the occurrence of rain. The experiment was carried out in vases under greenhouse conditions in Botucatu, São Paulo, Brazil. The weeds Brachiaria decumbens, Ipomoea grandifolia, Ipomoea hederifolia and Euphorbia heterophylla were sown and covered or not with sugarcane mulch. The experiment was arranged in a complete randomized design with four repetitions. The treatments were displaced in a 3x6 factorial scheme, with the factors being six periods without rain (0, 3, 7, 15, 30, and 60 days) and three modes of herbicide application(on the soil without sugarcane mulch, on and under sugarcane mulch). Control evaluations were carried out at 10, 21, 35 and 42 days after the occurrence of rain. The clomazone + hexazinone mixture promoted an excellent weed control for all the species studied when applied on, under, or without sugarcane mulch. However, the control levels tended to reduce for periods over 60 days without rain.

Towards coherent optical control of a single hole spin: Rabi rotation of a trion conditional on the spin state of the hole

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Electron spin resonance of Gd3+ in the antiferromagnetic heavy fermion CeIn3 and its reference compound LaIn3

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

Magnetic interactions and spin-reversal mechanism in ErMn1-xCoxO3-delta samples

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

Fast optical preparation, control, and readout of a single quantum dot spin

We propose and demonstrate the sequential initialization, optical control, and readout of a single spin trapped in a semiconductor quantum dot. Hole spin preparation is achieved through ionization of a resonantly excited electron-hole pair. Optical control is observed as a coherent Rabi rotation between the hole and charged-exciton states, which is conditional on the initial hole spin state. The spin-selective creation of the charged exciton provides a photocurrent readout of the hole spin state.

Incommensurate spin-density-wave and metal-insulator transition in the one-dimensional periodic Anderson model

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

Changing inter-molecular spin-orbital coupling for generating magnetic field effects in phosphorescent organic semiconductors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)