An integrated investigation of the Rio tailings, Panasqueira mine, Centre Portugal

The risks associated with mine tailings have different nature and, thus, only a multiple approach can investigate and monitor comprehensively the characteristics and evolution of mine tailings impacts on the environment. Deposition at the Rio tailings (Panasqueira Mine) lasted about ninety years. Over one million cubic metres, of complex very fine to fine material, are deposited on a mountain side overlaying the Zezere river, increasing the risk of contamination of one of the most important hydrographic basins in central Portugal. Herein, a multidisciplinary study including geophysics, geochemistry and borehole information, organized in a GIS, is used to characterize the Rio tailings. The geophysical survey comprised ERT (Electrical Resistivity Tomography) and GPR (Ground Penetrating Radar) on the mud impoundment, as well as, on the slope of the tailings. The geochemical survey consisted on collecting water and tailings samples, iron coatings, arsenopyrite stockpile material and ferruginous crust. Samples collected in boreholes, drilled specifically for this project, were also analyzed. The GIS provided imaging of the geophysical, geochemical and particle size spatial distribution, so that comparisons between the different data sets are easily done. Resistivity and GPR allowed bedrock positioning. GPR was able to give layering results within the tailings. Finally, comparison and correlation between geophysical and geochemical results are carried out and evaluated on the GIS platform

Performance implications of three-mirror Fabry-Perot demultiplexers for 10-Gb/s WDM dispersion-supported transmission with 0.5-nm channel spacing

This letter assesses the performance of dispersion-supported transmission (DST) for three 10-Gb/s WDM channels separated 0.5 nm, using a three-mirror Fabry-Perot demultiplexer. It is shown that the use of three-mirror demultiplexers reduces the crosstalk penalty to less than 1 dB in the region of small linear increase of dispersion penalty of the DST method, while double-cavity Fabry-Perot demultiplexers are less suitable to operate at this channel spacing. Compared with published performance studies for WDM-DST systems with 1 nm of channel spacing, these results indicate the channel spacing may be cut in a half, if a three-mirror filter is used as demultiplexe

Production, breeding and potential of cowpea crop in Brazil.

About 50 years ago cowpea was reported as a relatively minor tropical legume. However, in the last years, it has been emerging as one of the most important food legume of the 21st century (SINGH, 2010). Brazil is not out of this panorama. Brazilian agriculture is undergoing major technological changes and, in addition, globalization in agribusiness has caused impacts on the production chain of several crops, particularly those heavily dependent on the use of a large volume of agricultural inputs, mainly fertilizers and pesticides. Such crops have had a higher production cost each year. On the other hand, this situation has brought new opportunities. Business farmers have sought new alternatives for their production arrangements. In this context cowpea constitutes one of the best options.bitstream/item/85620/1/Doc-216-Production.pd

Composicao quimica e proteica de sementes de oito genotipos de feijao caupi (Vigna unguiculata (L.) Walp.).

Este trabalho objetivou avaliar a composicao quimica e o teor de proteinas soluveis de sementes de genotipos de feijao caupi. Foram utilizados no estudo os seguintes genotipo: BR 17 Gurgueia, BR 14 Mulato, TE90-180-88E, TE-180-13E. TE96-290-8G, TE96-290-9G, TE96-282-27G.bitstream/item/83180/1/CT1050001.pd

Novas doenças de plantas ornamentais no Estado do Ceará.

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Divergência genético-morfológica entre acessos de feijão caupi de porte semi-ereto e ereto.

O estudo da divergência é essencial para o melhoramento vegetal, pois possibilita a quantificação da variabilidade genética..