Morphology and composition of gold in a lateritic profile, Fazenda Pison ""Garimpo"", Amazon, Brazil

This study describes the morphological evolution of gold grains in a lateritic weathering profile in an equatorial rainforest climate. Primary sources of gold are quartz veins associated with shallow granophyric intrusion. Gold grains were found in fresh ore, saprolite, transition zones, ferruginous duricrust, red latosol, and yellow latosol. Irregularly shaped grains predominate, with smaller proportions of dendritic and prismatic forms. Gold grains are weathered in the uppermost 10 m of the regolith. Mean gold grain size is maximum in the duricrust (> 125 mu m) and decreases progressively upward into the yellow latosol (<90 mu m). Voids and corrosion pits appear on grain surfaces, and progressive rounding is observed from the bottom of the profile to the top. Gold grains can be classified as either homogeneous or zoned with respect to their chemical composition. Homogeneous grains contain 2-15% Ag (mean 8.3%). Zoned grains have more variable Ag contents; grain cores have means of approximately 10% or 23% Ag, with Ag-poor zones of approximately 3.7% Ag along internal discontinuities and/or outer rims. Formation of Ag-poor rims is due to preferential depletion of silver. Processes responsible for duricrust formation may preserve some grains as large aggregates, but subsequent transformation into latosol further modifies them. (c) 2007 Elsevier Ltd. All rights reserved.

THE SOUTHERN BRAZILIAN SHELF: GENERAL CHARACTERISTICS, QUATERNARY EVOLUTION AND SEDIMENT DISTRIBUTION

Extending from latitude 34 degrees S to 22 degrees S the Southern Brazilian shelf constitutes the only part of the Brazilian shelf with a subtropical to temperate environment. The studies on the different geological aspects of the area began in the 1960`s and have recently been reassessed after studies related to the determination of the Economic Exclusive Zone. In terms of morphology, the Southern Brazilian shelf may be divided into three sectors, the Sao Paulo Bight, the Florianopolis-Mostardas Sector and the Rio Grande Cone, characterized by conspicuous differences in terms of geological determining factors, bathymetry, declivities and the presence of canyons and channels. Despite the existence of hundreds of radiocarbon datings the sea level changes curve of southern Brazil during the Last Glacial Cycle is still a matter of debate. A recent controversy on the Middle and late Holocene sea level changes curve raised the question of the amplitude of the oscillations which occurred in the period. Also, a few but relatively consistent radiocarbon datings suggest the occurrence of a high sea level during Isotope Stage 3. In terms of sedimentary cover the Southern Brazilian shelf exhibits a very strong hydrodynamic control, both latitudinal and bathymetrical. The sector southward from 25 degrees S is characterized by the influence of the plume of water carrying sediments originating from the Rio de La Plata. Actually its presence is conspicuous up to 28 degrees S, with the area between this latitude and 25 degrees S constituting a transitional zone. In terms of bathymetry the outer shelf is marked by the ""floor-polisher"" effect of the Brazil Current, which is responsible for the maintenance of a relict facies in areas deeper than 100 meters.

Chemical variability within the marine sponge Aplysina fulva

Dibromotyrosine-derived metabolites are of common occurrence within marine sponges belonging to the order Verongida. However, previous chemical analysis of crude extracts obtained from samples of the verongid sponge Aplysina fulva collected in Brazil did not provide any dibromotyrosine-derived compounds. In this investigation, five samples of A. fulva from five different locations along the Brazilian coastline and one sample from a temperate reef in the South Atlantic Bight (SAB) (Georgia, USA) were investigated for the presence of bromotyrosine-derived compounds. All six samples collected yielded dibromotyrosine-derived compounds, including a new derivative, named aplysinafulvin, which has been identified by. analysis of spectroscopic data. These results confirm previous assumptions that dibromotyrosine-derived metabolites can be considered as chemotaxonomic markers of verongid sponges. The isolation of aplysinafulvin provides additional support for a biogenetic pathway involving an arene oxide intermediate in the biosynthesis of Verongida metabolites. It cannot yet be established if the chemical variability observed among the six samples of A.fulva collected in Brazil and the SAB is the result of different environmental factors, distinct chemical extraction and isolation protocols, or a consequence of hidden genetic diversity within the postulated morphological plasticity of this species. (C) 2007 Elsevier Ltd. All rights reserved.

Outdoor performance of forest seedlings pre-cultivated under artificial lights : effects of the light spectra used for pre-cultivation on the future establishment and development

Forest nurseries are essential for producing good quality seedlings, thus being a key element in the reforestation process. With increasing climate change awareness, nursery managers are looking for new tools that can help reduce the effects of their operations on the environment. The ZEPHYR project, funded by the European Commission under the Seventh Framework Programme (FP7), has the objective of finding new alternatives for nurseries by developing innovative zero-impact technologies for forest plant production. Due to their direct relationship to the energy consumption of the nurseries, one of the main elements addressed are the grow lights used for the pre-cultivation. New LED luminaires with a light spectrum tailored to the seedlings’ needs are being studied and compared against the traditional fluorescent lamps. Seedlings of Picea abies and Pinus sylvestris were grown under five different light spectra (one fluorescent and 4 LED) during 5 weeks with a photoperiod of 16 hours at 100 μmol∙m-2∙s-1 and 60% humidity. In order to evaluate if these seedlings were able cope with real field stress conditions, a forest field trial was also designed. The terrain chosen was a typical planting site in mid-Sweden after clear-cutting. Two vegetation periods after the outplanting, the seedlings that were pre-cultivated under the LED lamps have performed at least as well as those that were grown under fluorescent lights. These results show that there is a good  potential for lightning substitution in forestry nurseries.

Steel Sheet Applications and Integrated Heat Management

Increasing energy use has caused many environmental problems including global warming. Energy use is growing rapidly in developing countries and surprisingly a remarkable portion of it is associated with consumed energy to keep the temperature comfortable inside the buildings. Therefore, identifying renewable technologies for cooling and heating is essential. This study introduced applications of steel sheets integrated into the buildings to save energy based on existing technologies. In addition, the proposed application was found to have a considerable chance of market success. Also, satisfying energy needs for space heating and cooling in a single room by using one of the selected applications in different Köppen climate classes was investigated to estimate which climates have a proper potential for benefiting from the application. This study included three independent parts and the results related to each part have been used in the next part. The first part recognizes six different technologies through literature review including Cool Roof, Solar Chimney, Steel Cladding of Building, Night Radiative Cooling, Elastomer Metal Absorber, and Solar Distillation. The second part evaluated the application of different technologies by gathering the experts’ ideas via performing a Delphi method. The results showed that the Solar Chimney has a proper chance for the market. The third part simulated both a solar chimney and a solar chimney with evaporation which were connected to a single well insulated room with a considerable thermal mass. The combination was simulated as a system to estimate the possibility of satisfying cooling needs and heating needs in different climate classes. A Trombe-wall was selected as a sample design for the Solar Chimney and was simulated in different climates. The results implied that the solar chimney had the capability of reducing the cooling needs more than 25% in all of the studied locations and 100% in some locations with dry or temperate climate such as Mashhad, Madrid, and Istanbul. It was also observed that the heating needs were satisfied more than 50% in all of the studied locations, even for the continental climate such as Stockholm and 100% in most locations with a dry climate. Therefore, the Solar Chimney reduces energy use, saves environment resources, and it is a cost effective application. Furthermore, it saves the equipment costs in many locations. All the results mentioned above make the solar chimney a very practical and attractive tool for a wide range of climates.