Understanding the factors that contribute to U^Pb discordance in zircon is essential for interpreting isotopic data and for assessing the validity of concordia intercept ages. Modification caused by interaction with metamorphic fluids is often cited as a primary means by which significant or even complete isotopic resetting of U^Pb systematics in zircon might be achieved under subsolidus condit...

In the carbonate soils contaminated by a toxic spill from a pyrite mine (Aznalcóllar, southern Spain), a study was made of a thin layer (thickness = 4 mm) of polluted soil located between the pyrite tailings and the underlying soil. This layer, reddish-yellow in color due to a high Fe content, formed when sulfates (from the oxidation of sulfides) infiltrated the soil, causing acidification (to ...

Historical mining activities cause widespread, long-term trace metal contamination of freshwater ecosystems. However, measuring bioavailability has proven difficult, because it depends on many factors, not least concentrations in water, sediment and habitat. Simple tools are needed to assess bioavailabilities. The use biomonitors been widely advocated provide a realistic measure. To date there ...

Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability den...

Abstract Wadi Abu Subeira area contains many farms and houses is one of the promising areas for iron mining. Therefore, 21 surface soil samples were collected investigated toxic heavy metals (Pb, Cr, Ni, Cu, Zn, Co, As) using inductively coupled plasma (ICP) to establish a geochemical baseline these during pre-mining conditions. To decipher sources their interrelationships, multivariate statist...

Norepinephrine and histamine markedly augment accumulations of cyclic AMP elicited by 2-chloroadenosine in a guinea pig cerebral cortical vesicular preparation. In addition, these biogenic amines stimulate phosphatidylinositol turnover. Phosphatidylinositol turnover is associated with mobilization of internal calcium and with stimulation of protein kinase C. Phorbol-12-myristate-13-acetate (PMA...

In this research, the effect of light intensity and salinity regimes on element levels Treptacantha barbata (formerly Cystoseira barbata) was studied, elemental compositions brown alga collected from wild stocks also compared with cultured ones. culture trials, 11 different experiments that have ranges as 50 to 150 µmol photon m-2s-1 24 ‰ 42 were designed according response surface methodology ...

geometrical computation: Turing-computing ability and unpredictable accumulations (extended abstract) Jérôme Durand-Lose Mars 2004 Research Report N 2004-09 École Normale Supérieure de Lyon 46 Allée d’Italie, 69364 Lyon Cedex 07, France Téléphone : +33(0)4.72.72.80.37 Télécopieur : +33(0)4.72.72.80.80 Adresse électronique : [email protected] Abstract geometrical computation: Turing-computing abil...