Acúmulo de nutrientes e tempo de decomposição da palhada de espécies forrageiras em função de épocas de semeadura

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

Spray deposition on weeds of common bean crops

A.C.P. Rodrigues-Costa, D. Martins, N.V. Costa, and M.R.R. Pereira. 2011. Spray deposition on weeds of common bean crops. Cien. Inv. Agr. 38(3): 357-365. Weed control failure in common bean (Phaseolus vulgaris L.) production may be related to inappropriate herbicide application techniques. The purpose of this study, therefore, was to evaluate the amount of spray solution deposition that occurred on the weeds, Bidens pilosa L. and Brachiaria plantaginea (Link) Hitch., both within and between rows of common beans. The research was arranged in a randomized block design with four replications. The following 6 spray nozzles were used: flat fan nozzles XR 110015 VS (150 L ha(-1)) and XR 11002 VS (200 L ha(-1)); cone nozzles TX VK 6 (150 L ha(-1)) and TX VK 8 (200 L ha(-1)); and twin flat fan nozzles TJ60 11002 VS (150 L ha(-1)) and TJ60 11002 VS (200 L ha-1). The results showed that the loss of the spray solution on the soil occurred mainly within the bean rows and with a high intensity when using a nozzle spraying 200 L ha(-1). At 30 days after sowing, the TX (150 L ha(-1)) nozzle was the only nozzle that promoted deposits of less than 210.0 mu L g(-1) of dry mass. The spray nozzles showed a good performance in the deposition of the spray solution on the weeds that occurred both within and between the rows. However, for both species there was great variation in individual deposits depending on their location in relationship to the plants.

Molecular architecture of thin films fabricated via physical vapor deposition and containing a poly(azo)urethane

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

Food restriction and refeeding induces changes in lipid pathways and fat deposition in the adipose and hepatic tissues in rats with diet-induced obesity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Deposition and characterization of BiVO4 thin films and evaluation as photoanodes for methylene blue degradation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of Intensive Agriculture on Dry Deposition of Aerosol Nutrients

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Deposition and photo-induced electrical resistivity of dip-coated NiO thin films from a precipitation process

Thin films of the semiconductor NiO are deposited using a straightforward combination of simple and versatile techniques: the co-precipitation in aqueous media along with the dip- coating process. The obtained material is characterized by gravimetric/differential thermal analysis (TG-DTA) and X-ray diffraction technique. TG curve shows 30 % of total mass loss, whereas DTA indicates the formation of the NiO phase about 578 K (305 C). X-ray diffraction (XRD) data confirms the FCC crystalline phase of NiO, whose crystallinity increases with thermal annealing temperature. UV-Vis optical absorption measurements are carried out for films deposited on quartz substrate in order to avoid the masking of bandgap evaluation by substrate spectra overlapping. The evaluated bandgap is about 3.0 eV. Current-voltage (I-V) curves measured for different temperatures as well as the temperature-dependent resistivity data show typical semiconductor behavior with the resistivity increasing with the decreasing of temperature. The Arrhenius plot reveals a level 233 meV above the conduction band top, which was attributed to Ni2+ vacancy level, responsible for the p-type electrical nature of NiO, even in undoped samples. Light irradiation on the films leads to a remarkable behavior, because above bandgap light induced a resistivity increase, despite the electron-hole generation. This performance was associated with excitation of the Ni 2+ vacancy level, due to the proximity between energy levels. © 2012 Springer Science+Business Media New York.

An analysis of diurnal cycles in the mass of ambient aerosols derived from biomass burning and agro-industry

Strong diurnal cycles in ambient aerosol mass were observed in a rural region of Southeast Brazil where the trace composition of the lower troposphere is governed mainly by emissions from agro-industry. An optical particle counter was used to record size-segregated aerosol number concentrations between 13 May 2010 and 15 March 2011. The data were collected every 10 min and used to calculate aerosol mass concentrations. Aerosol samples were also collected onto filters during daytime (10:00-16:00 local time) and nighttime (20:00-06:00) periods, for subsequent analysis of soluble ions and water-soluble organic carbon. Biomass burning aerosols predominated during the dry winter, while secondary aerosols were most important in the summer rainy season. In both seasons, diurnal cycles in calculated aerosol mass concentrations were due to the uptake of water by the aerosols and, to a lesser extent, to emissions and secondary aerosol formation. In neither season could the observed mass changes be explained by changes in the depth of the boundary layer. In the summer, nighttime increases in aerosol mass ranged from 2.7-fold to 81-fold, depending on particle size, while in the winter, the range was narrower, from 2.2-fold to 9.5-fold, supporting the possibility that the presence of particles derived from biomass burning reduced the overall ability of the aerosols to absorb water. Key Points Diurnal cycle of agro-industrial aerosol mass governed by humidity Biomass burning emissions act to suppress particle growth Need to consider diurnal mass cycles in aerosol dry deposition models ©2013. American Geophysical Union. All Rights Reserved.

Evidence for euphotic zone anoxia during the deposition of Aptian source rocks based on aryl isoprenoids in petroleum, Sergipe-Alagoas Basin, northeastern Brazil

Four crude oil samples from the Sergipe-Alagoas Basin, northeastern Brazil, were analyzed using full scan gas chromatography-quadrupole mass spectrometry (GC-qMS) for biomarkers, in order to correlate them using aromatic carotenoids thereby enhancing knowledge about the depositional environment of their source rocks. The geochemical parameters derived from saturated fractions of the oils show evidence of little or no biodegradation and similar thermal maturation (Ts/(Ts+Tm) for terpanes, C29 αββ/(αββ+ααα), C27, and C29 20S/(20S+20R) for steranes). Low pristane/phytane ratios and the abundance of gammacerane and β-carotane are indicative of an anoxic and saline depositional environment for the source rocks. Moreover, we identified a large range of diagenetic and catagenetic products of the aromatic carotenoid isorenieratene, including C40, C33, and C32 diaryl isoprenoids and aryl isoprenoid derivatives with short side chains and/or additional rings. These results indicate anoxia in the photic zone during the deposition of the source rocks. © 2013 The Authors.