Estimation of carbon stock and nitrogen in the semiarid region.

The management and use of the soil in semi-arid areas, over time have caused significant decreases of carbon (C) and nitrogen (N) in these soils, due to the fact that it is a region where normally enough conditions are found favorable to the different decomposition processes of MOS, with man being the main agent responsible for these phenomena

Proposal for a collaborative LCA data management methodological aproach for creating "nodes" in the brazilian national inventory database (SICV) Brasil.

Global Guidance proposes mechanisms for LCA studies and data management for improving interoperability, data exchange, accessibility and credibility of LCA databases. The PBACV (CONMETRO, 2010) has among its objectives to implement in Brazil a system capable of organizing, storing and disseminating information of LCIs. The Brazilian government responded to this demand through IBICT, which developed the SICV Brazil. For a LCI database to succeed, it is necessary to have primary data provided by the productive sector. The availability of data contributes to the growth of the country while benefiting the primary data providers, as society is increasingly attentive to the transparency and environmental awareness of companies. The management of LCA data is not a concern of national LCI databases alone. Other institutions also need to manage their LCA data independently of proprietary software, ensuring autonomy and sustainability for their operations. Keeping data on someone?s own infrastructure favors autonomy, but multiplies infrastructure investment and impairs interoperability. This research proposes a procedure for shared management of LCA data through the creation nodes, an instance of SICV Brazil for storing LCI data from private and public institutions. This procedure for shared management promoted the Brazilian National Inventory Database (SICV Brazil) and offered advanced information resources to institutions, such as Embrapa, without additional infrastructure and facilitating interoperability with other institutions. Authors believe that the creation of other instances of the SICV could contribute to the advance of LCA in Brazil

On the Nonlinear Stability of Asymptotically Anti-de Sitter Solutions

Despite the recent evidence that anti-de Sitter spacetime is nonlinearly unstable, we argue that many asymptotically anti-de Sitter solutions are nonlinearly stable. This includes geons, boson stars, and black holes. As part of our argument, we calculate the frequencies of long-lived gravitational quasinormal modes of AdS black holes in various dimensions. We also discuss a new class of asymptotically anti-de Sitter solutions describing noncoalescing black hole binaries.Comment: 26 pages. 5 figure

Excitations in the Halo Nucleus He-6 Following The Li-7(gamma,p)He-6 Reaction

A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers considerable validity to this observation.Comment: 3 pages of LaTeX, 3 figures in PostScript, approved for publication in Phys. Rev. C, August, 200

Excitations in the deformed D1D5 CFT

We perform some simple computations for the first order deformation of the D1D5 CFT off its orbifold point. It had been shown earlier that under this deformation the vacuum state changes to a squeezed state (with the further action of a supercharge). We now start with states containing one or two initial quanta and write down the corresponding states obtained under the action of deformation operator. The result is relevant to the evolution of an initial excitation in the CFT dual to the near extremal D1D5 black hole: when a left and a right moving excitation collide in the CFT, the deformation operator spreads their energy over a larger number of quanta, thus evolving the state towards the infrared.Comment: 26 pages, Latex, 4 figure

Comparison of some theoretical models for fittings of the temperature dependence of the fundamental energy gap in GaAs

In this work we report on a comparison of some theoretical models usually used to fit the dependence on temperature of the fundamental energy gap of semiconductor materials. We used in our investigations the theoretical models of Viña, Pässler-p and Pässler-ρ to fit several sets of experimental data, available in the literature for the energy gap of GaAs in the temperature range from 12 to 974 K. Performing several fittings for different values of the upper limit of the analyzed temperature range (Tmax), we were able to follow in a systematic way the evolution of the fitting parameters up to the limit of high temperatures and make a comparison between the zero-point values obtained from the different models by extrapolating the linear dependence of the gaps at high T to T = 0 K and that determined by the dependence of the gap on isotope mass. Using experimental data measured by absorption spectroscopy, we observed the non-linear behavior of Eg(T) of GaAs for T > ΘD.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNP