Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

In this work, we report the preparation of a superconductor thin film of the BSCCO system using a good quality powder with nominal composition Bi_{1.8}Pb_{0.4}Sr_2CaCu_2O_x which was thermally treated using a domestic microwave oven (2.45 GHz, 800 W). This film was grew on a single crystal of LaAlO_3(100) substrate and exhibited a crystalline structure with the c-axis perpendicular to the plane of the substrate. An onset superconducting transition temperature was measured at 80 K.Comment: 4 pages, 5 figure

Dynamics of a Generalized Cosmological Scalar-Tensor Theory

A generalized scalar-tensor theory is investigated whose cosmological term depends on both a scalar field and its time derivative. A correspondence with solutions of five-dimensional Space-Time-Matter theory is noted. Analytic solutions are found for the scale factor, scalar field and cosmological term. Models with free parameters of order unity are consistent with recent observational data and could be relevant to both the dark-matter and cosmological-"constant" problems.Comment: 13 page

Zinc abundances in Galactic bulge field red giants: implications for DLA systems

Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman-alpha systems, permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman-alpha systems, in order to better understand the chemical evolution in these environments. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We find [Zn/Fe]=+0.24+-0.02 in the range -1.3 < [Fe/H] < -0.5 and [Zn/Fe]=+0.06+-0.02 in the range -0.5 < [Fe/H] -0.1, it shows a spread of -0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe]<0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge.Comment: Accepted in Astronomy & Astrophysics, in press Date of acceptance: 13/05/2015. 19 pages, 14 Figs in Astronomy & Astrophysics, 201

Adubação nitrogenada no feijoeiro cultivado sob palhadas de diferentes culturas.

O objetivo deste trabalho é avaliar a resposta do feijoeiro irrigado, cultivado sob plantio direto em sucessão a diferentes culturas, à adubação nitrogenada em cobertura.bitstream/CNPAF-2009-09/27950/1/comt_159.pd

Determination of tetracycline and its major degradation products by liquid chromatography with fluorescence detection

A liquid chromatographic method of tetracycline and its major degradation products on a C8-reversed phase column with acidic mobile phase and fluorescence detection is described. The quantification limit, measured as the amount of sample that gave a signal ten times the peak-to-peak noise of the baseline, was: 0.25 ng for tetracycline (TC) and epitetracycline (ETC), 25 ng for and 4-epianhydrotetracycline (EATC) and 50 ng for anhydrotetracycline (ATC) of injected standard. By means of this liquid chromatography (LC) assay TC, ETC, EATC and ATC as main degradation products of tetracycline, can be separated and determined with good sensitivity and specificity within 15 min.http://www.sciencedirect.com/science/article/B6TGX-43HVHWC-1D/1/9763379e028400de01242a673bd4528

The impact of the implementation of an integrated crop-livestock-forest system in a Ferralsol of the brazilian savannah (Cerrado).

This study aimed to contribute to the analysis of an iCLF system in the Brazilian savannah in Goiás state.Coordenador Roberto Giolo de Almeida. II SIGEE