Effects of gaseous atmosphere and antioxidants on the development and cryotolerance of bovine embryos at different periods of in vitro culture

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

Continental degassing of He-4 by surficial discharge of deep groundwater

Radiogenic He-4 is produced by the decay of uranium and thorium in the Earths mantle and crust. From here, it is degassed to the atmosphere(1-5) and eventually escapes to space(1,5,6). Assuming that all of the He-4 produced is degassed, about 70% of the total He-4 degassed from Earth comes from the continental crust(2,-5,7). However, the outgoing flux of crustal He-4 has not been directly measured at the Earths surface(2) and the migration pathways are poorly understood(2-4,7,8). Here we present measurements of helium isotopes and the long-lived cosmogenic radio-isotope Kr-81 in the deep, continental-scale Guarani aquifer in Brazil and show that crustal He-4 reaches the atmosphere primarily by the surficial discharge of deep groundwater. We estimate that He-4 in Guarani groundwater discharge accounts for about 20% of the assumed global flux from continental crust, and that other large aquifers may account for about 33%. Old groundwater ages suggest that He-4 in the Guarani aquifer accumulates over half- to one-million-year timescales. We conclude that He-4 degassing from the continents is regulated by groundwater discharge, rather than episodic tectonic events, and suggest that the assumed steady state between crustal production and degassing of He-4, and its resulting atmospheric residence time, should be re-examined.

Quality assessment of eggs packed under modified atmosphere

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

Photoluminescence of the Eu-doped thin film heterojunction GaAs/SnO2 and rare-earth doping distribution

Tin dioxide (SnO2) thin films doped with Eu3+, are deposited by the sol-gel-dip-coating process on top of GaAs films, which is deposited by resistive evaporation on glass substrate. This heterojunction assembly presents luminescence from the rare-earth ion, unlike the SnO2 deposition directly on a glass substrate, where emissions from the Eu3+ transitions are absent. The Eu3+ transitions are clearly identified and are similar to the observation on SnO2 pressed powder (pellets), thermally treated at much higher temperatures. However, in the form of heterojunction films, the Eu emission comes along a broad band, located at higher energy compared to Eu3+ transitions, which is blue-shifted as the thermal annealing temperature increases. The size of nanocrystallites points toward quantum confinement or electron transfer between oxygen vacancies, originated from the disorder in the material, and trivalent rare-earth ions, which present acceptor-like character in this matrix. This electron transfer may relax for higher temperatures in the case of pellets, and the broad band is eliminated.

Natural formations at the Earth-Moon triangular point in perturbed restricted problems

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

Thermal study and characterization of nicotinates of some alkaline earth metals using TG-DSC-FTIR and DSC-system photovisual

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

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)

Pareto Frontier for the time-energy cost vector to an Earth-Moon transfer orbit using the patched-conic approximation

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

Corrosion resistance of 2024 aluminum alloy coated with plasma deposited a-C:H:Si:O films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

alpha-SiAlON-SiC composites obtained by gas-pressure sintering and hot-pressing

The objective of this work was the obtaining in situ of alpha-SiAlON-SiC composite, using an alternative rare-earth oxide mixture, RE2O3, as sintering additive, by two different sintering processes. As sintering additive, 20 vol.% of AlN-RE2O3 in a molar ratio of 90: 10 was mixed to the alpha-Si3N4 powder. In the Si3N4-AlN-RE2O3 powder mixture, 0, 10, 15 and 20wt.% of SiC were added. The powder batches were milled, dried and compacted by cold isostatic pressing. Two different sintering processes were used: gas-pressure sintering at 1950 degrees C for 1 h under 1.5 MPa of N-2 atmosphere, or uniaxial hot-pressing at 1750 degrees C, for 30 min under pressure of 20 MPa. The sintered samples were characterized by X-ray diffraction, scanning electron microscopy and mechanical properties. XRD patterns indicate only alpha-SiAlON (alpha') and beta-SiC as crystalline phases. It was observed that the SiC addition did not influence the alpha-SiAlON formation, although the growth of elongated alpha'-grains is substantially decreased. The hot-pressed composites presented better mechanical properties, exhibiting fracture toughness of 5 MPa m(1/2) and hardness around 21.5 GPa. (c) 2007 Elsevier B.V. All rights reserved.

Lithium intercalation into double rare earth chromates

Lithium intercalation into double rare earth chromates was carried out. It was found that the compounds NaxLi1-xLa(CrO4)2 belong to the NaLa(CrO4)2 structural type and may be recommended as fast ionic conductors. At small values of x a third polymorphous modification of LiLa(CrO4)2 can be stabilized. Attempts to intercalate lithium into CsLa(CrO4)2 lead to collapse of the lamellar network with the formation of LaCrO4 and alkaline chromates. Ion exchange Li+/H+ data are consistent with these considerations. © 1994.

Estudo de manobras evasivas com perturbações orbitais

Pós-graduação em Física - FEG

Topografia convencional na aferição de áreas obtidas por georreferenciamento e Google Earth

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Rainwater chemical composition and annual atmosphere depositon in Sorocaba (SP)

This work evaluated the rainwater chemical composition and the annual atmospheric deposition in Sorocaba, (Sao Paulo State), Brazil. One sampling ˜ point was chosen and forty samples were collected between January and December 2006. The analyses were performed for pH, electrical conductivity, sodium, calcium, potassium, magnesium, sulphate, nitrate, phosphate, alkalinity and chloride. The rainwater pH varied from 5.20 to 6.40, being Ca2+ the main ion responsible for controlling the rainwater pH. The ionic concentration decreases in the following order: Ca2+>Na+> K+>Mg2+ for cations and SO2− 4 >HCO− 3 >NO− 3 >Cl−>PO3− 4 for anions. The annual atmospheric deposition appears to be controlled by the following sources: mining activities and cement factories (Ca2+ and HCO− 3 ), agricultural activities (K+, NO− 3 and PO3− 4 ), soil dust (Na+, Mg2+ and HCO− 3 ) and fossil fuel burning (SO2− 4 )

Does diatomaceous earth control leaf-cutter ants (Hymenoptera: Formicidae) in the Eucalyptus plantations?

Genus Atta includes some of the most important Formicidae leaf cutter ants which cause extensive damage to the eucalyptus plantations. Atta sexdens rubropilosa Forel, one of the chief pests in Brazilian reforestation, can restrict and reduce forest productivity by its intense and constant leaf-cutting activities on plants at all stages. Therefore, the demand for new products to control A. sexdens rubropilosa indicates the study of the utilization of the dry powder formulation of diatomaceous earth (DE) against this pest in the eucalyptus cultivars. The study was conducted using 120 colonies of A. sexdens rubropilosa in Eucalyptus grandis Hill ex. Maiden x Eucalyptus urophylla Blake (Myrtaceae) (urograndis) stand. The randomized block experimental design was used with six treatments (1, 10, 25, and 50 g/m2 of DE, 6.0 g/m2 sulfluramid bait per square meter of loose soil, and the control) with five replications, each with four colonies of this ant. Diatomaceous earth was applied to the active A. sexdens rubropilosa ant holes, and the sulfluramid bait was applied in bulk in a localized manner. The control efficacy of A. sexdens rubropilosa with DE was low, showing values similar to that of the control, and, for this reason, it cannot be used to control this ant. The bait with sulfluramid showed higher efficacy than those of the other treatments.