Strategies for plane change of Earth orbits using lunar gravity and derived trajectories of family G

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

The swing-by effect in the Vesta-Magnya case. Single and multiple encounters.

It was verified that the asteroid Magnya has some physical and chemical characteristics similar to the bodies from Vesta family. However, astronomical observations revealed that Magnya is distant from these bodies. In the present work, we assumed that Magnya originated from Vesta and we try to justify its current distant orbital location taking into account the effects of close encounters between Magnya and Vesta. The methodology adopted involved an analytical approach considering the technique of the gravity assisted maneuver, also known as swing-by. We found that the energy variation achieved through a single swing-by between Vesta and Magnya are very small when compared to the variation that would be required to change the orbit of Magnya. The effects of multiple close encounters were also considered and discussed. We concluded that the possibility of multiple encounters is limited, and therefore, that Magnya should suffer other perturbations (such as resonances, collisions or close encounters with other bodies, for instance) that would provide the supposed change in its orbit.

Chaotic Dynamics in a Low-Energy Transfer Strategy to the Equilateral Equilibrium Points in the Earth-Moon System

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

Alternative transfer to the Earth-Moon Lagrangian points L4 and L5 using lunar gravity assist

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

Chemical Composition of Lipids Present in Cat and Dog Oocyte by Matrix-Assisted Desorption Ionization Mass Spectrometry (MALDI- MS)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of discontinuous Percoll gradient centrifugation on the quality of bovine spermatozoa evaluated with computer-assisted semen analysis and fluorescent probes association

The objective of this study was to evaluate the quality of bovine frozen-thawed sperm cells after Percoll gradient centrifugation. Frozen semen doses were obtained from six bulls of different breeds, including three taurine and three Zebu animals. Four ejaculates per bull were evaluated before and after discontinuous Percoll gradient centrifugation. Sperm motility was assessed by computer-assisted semen analysis and the integrity of the plasma and acrosomal membranes, as well as mitochondrial function, were evaluated using a combination of fluorescent probes propidium iodide, fluorescein isothiocyanate-conjugated Pisum sativum agglutinin and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide. The procedure of Percoll gradient centrifugation increased the percentage of total and progressive sperm motility, beat frequency, rectilinear motility, linearity and rapidly moving cells. In addition, the percentage of cells with intact plasma membrane and mitochondrial membrane potential was increased in post-centrifugation samples. However, the percentage of sperm cells with intact acrosomal membrane was markedly reduced. The method used selected the motile cells with intact plasma membrane and higher mitochondrial functionality in frozen-thawed bull semen, but processing, centrifugation and/or the Percoll medium caused damage to the acrosomal membrane.

Demecolcine Effects on Microtubule Kinetics and on Chemically Assisted Enucleation of Bovine Oocytes

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

Chemically Assisted Enucleation Results in Higher G6PD Expression in Early Bovine Female Embryos Obtained by Somatic Cell Nuclear Transfer

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

Validation of microsatellite markers for assisted selection of soybean genotypes resistant to powdery mildew

Powdery mildew is one of the most serious diseases of soybean and is found in all producing countries. The purpose of this study was to validate microsatellite markers previously identified as associated with resistance to powdery mildew in soybean. The study was conducted in two F, parent populations with contrasting resistance to powdery mildew, In the analysis 10 SSR primers were used for the populations. and tour polymorphic markers were identified for cross I (MGBR95-20937 x IAC-Foscarin 31) and three for cross 2 (MGBR-46 x Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48). The Chi-square analysis of the phenotypic evaluation confirmed the expected segregation (3: 1) of a dominant gene related to resistance. The polymorphic markers also segregated as expected (1:2:1). The markers Sat 366 and Sat 393 in the crosses 1 and 2. respectively, located at 9.41 and 12.45 cM from the gene. were considered promising for marker-assisted selection for resistance to powdery mildew in soybean. at a selection efficiency of 92.7% and 60.3% respectively.

Air-assisted boom sprayer and spray deposition on bean plants

A possibilidade do desenvolvimento de técnicas de aplicação de produtos fitossanitários mais seguras, com menores volumes de calda, número de aplicações e deriva, aliados à necessidade de se obter melhores níveis de controle dos agentes nocivos às plantas cultivadas, justificam o uso da assistência de ar junto à barra de pulverização. Com o objetivo de avaliar a deposição da pulverização na cultura do feijoeiro (Phaseolus vulgaris), em presença e ausência da assistência de ar junto à barra de pulverização, com diferentes pontas de pulverização e volumes de calda, foi conduzido um experimento em delineamento inteiramente casualizado, utilizando-se como traçador o óxido cuproso. Alvos artificiais (papel filtro com 3 x 3 cm) foram afixados nas superfícies adaxial e abaxial de folíolos posicionados nos terços superior e inferior de plantas, selecionadas ao acaso, distribuídas perpendicularmente ao deslocamento do pulverizador. Após a aplicação do traçador os coletores foram lavados individualmente em solução extratora de ácido nítrico a 1,0 mol L-1. A determinação quantitativa dos depósitos foi realizada com o uso da espectrofotometria de absorção atômica. A assistência de ar junto à barra de pulverização não aumentou a deposição do traçador em folíolos de feijoeiro, aos 48 dias após a emergência da cultura.

Morphological and Structural changes of CaxSr1-xTiO3 Powders Obtained by the Microwave-Assisted Hydrothermal Method

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

Photoluminescence of barium-calcium titanates obtained by the microwave-assisted hydrothermal method (MAH)

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

g-acceleration of gravity: its measurement from the shape of water by using a computerized rotational system

This paper proposes a different experimental setup compared with the traditional ones, in order to determine the acceleration of gravity, which is carried out by using a fluid at a constant rotation. A computerized rotational system-by using a data acquisition system with specific software, a power amplifier and a rotary motion sensor-is employed in order to evaluate the angular velocity and g. An equation to determine g is inferred from fluid mechanics. For this purpose, the fluid's parabolic shape inside a cylindrical receptacle is considered using a rotational movement.

DFT study of the water-assisted tautomerization process between hydrated oxide, MO(H2O)(+), and dihydroxide, M(OH)(2)(+) cations (M = V, Nb and Ta)

Density functional theory (DFT) calculations point out that the participation of water can effectively lower the barrier height for the isomerization process between hydrated oxide cation, MO(H2O)(+), and dihydroxide cation, M(OH)(2)(+), (M = V, Nb and Ta). The catalytic effect is achieved by a water-assisted mechanism in which water acts as proton donor and acceptor, via a transition structure corresponding to a six-membered ring. In the case of vanadium atom, the presence of two water molecules has been taken into account and the tautomerization becomes nearly barrierless, decreasing both the stability of the transition structures relative to intermediates and the depths of wells associated with the intermediates. (C) 2003 Elsevier B.V. All rights reserved.

Structural and optical properties of CaTiO3 perovskite-based materials obtained by microwave-assisted hydrothermal synthesis: An experimental and theoretical insight

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)