Importância econômica.

Sorgo no Brasil; A expansão do sorgo nos anos 90

Intercomparison of carbonate chemistry measurements on a cruise in northwestern European shelf seas

Four carbonate system variables were measured in surface waters during a cruise aimed at investigating ocean acidification impacts traversing northwestern European shelf seas in the summer of 2011. High-resolution surface water data were collected for partial pressure of carbon dioxide (pCO2; using two independent instruments) and pH using the total pH scale (pHT), in addition to discrete measurements of total alkalinity and dissolved inorganic carbon. We thus overdetermined the carbonate system (four measured variables, two degrees of freedom), which allowed us to evaluate the level of agreement between the variables on a cruise whose main aim was not intercomparison, and thus where conditions were more representative of normal working conditions. Calculations of carbonate system variables from other measurements generally compared well with direct observations of the same variables (Pearson’s correlation coefficient always greater than or equal to 0.94; mean residuals were similar to the respective accuracies of the measurements). We therefore conclude that four of the independent data sets of carbonate chemistry variables were of high quality. A diurnal cycle with a maximum amplitude of 41 μatm was observed in the difference between the pCO2 values obtained by the two independent analytical pCO2 systems, and this was partly attributed to irregular seawater flows to the equilibrator and partly to biological activity inside the seawater supply and one of the equilibrators. We discuss how these issues can be addressed to improve carbonate chemistry data quality on future research cruises

Cosmological model with non-minimally coupled fermionic field

A model for the Universe is proposed whose constituents are: (a) a dark energy field modeled by a fermionic field non-minimally coupled with the gravitational field, (b) a matter field which consists of pressureless baryonic and dark matter fields and (c) a field which represents the radiation and the neutrinos. The coupled system of Dirac's equations and Einstein field equations is solved numerically by considering a spatially flat homogeneous and isotropic Universe. It is shown that the proposed model can reproduce the expected red-shift behaviors of the deceleration parameter, of the density parameters of each constituent and of the luminosity distance. Furthermore, for small values of the red-shift the constant which couples the fermionic and gravitational fields has a remarkable influence on the density and deceleration parameters.Comment: Accepted for publication in Europhysics Letter

Sorgo: introdução e importância econômica.

A produção de sorgo vem apresentando no Brasil um crescimento notável nos últimos anos, após situar-se ao redor de 300.000 t até 1996. A partir deste ano, a quantidade de grãos de sorgo colhida evoluiu continuamente até atingir valores próximos a 900.000 t. Isto é o reflexo de uma série de mudanças que ocorreram no agronegócio brasileiro, que criaram as condições tanto para este incremento como para absorção da produção resultante. Para criar condições que sustentem novos períodos de crescimento da produção e consumo do sorgo no Brasil, é necessário um maior conhecimento das características da planta do sorgo e de suas formas mais comuns de processamento em outras regiões do mundo. A experiência de outros agricultores e processadores pode ser de grande utilidade para identificar possíveis áreas e condições edafoclimáticas com características semelhantes no Brasil que possam ser objeto de experiências para implantação de lavouras de sorgo. O mesmo pode ser considerado com relação a formas de utilização dos grãos.bitstream/CNPMS/16217/1/Doc_26.pd

An Intervention-AUV learns how to perform an underwater valve turning

Intervention autonomous underwater vehicles (I-AUVs) are a promising platform to perform intervention task in underwater environments, replacing current methods like remotely operate underwater vehicles (ROVs) and manned sub-mersibles that are more expensive. This article proposes a complete system including all the necessary elements to perform a valve turning task using an I-AUV. The knowledge of an operator to perform the task is transmitted to an I-AUV by a learning by demonstration (LbD) algorithm. The algorithm learns the trajectory of the vehicle and the end-effector to accomplish the valve turning. The method has shown its feasibility in a controlled environment repeating the learned task with different valves and configurations