57 resultados para 5-Methoxy-3,4-dehydroxanthomegnin
Resumo:
Temporal variations in concentrations of perfluorinated carboxylic acids (PFCAs) and sulfonic acids (PFSAs), including perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) structural isomers, were examined in livers of pilot whale (Globicephala melas), ringed seal (Phoca hispida), minke whale (Balaenoptera acutorostrata), harbor porpoise (Phocoena phocoena), hooded seal (Cystophora cristata), Atlantic white-sided dolphin (Lagenorhynchus acutus) and in muscle tissue of fin whales (Balaenoptera physalus). The sampling spanned over 20 years (1984-2009) and covered a large geographical area of the North Atlantic and West Greenland. Liver and muscle samples were homogenized, extracted with acetonitrile, cleaned up using hexane and solid phase extraction (SPE), and analyzed by liquid chromatography with negative electrospray tandem mass spectrometry (LC-MS/MS). In general, the levels of the long-chained PFCAs (C9-C12) increased whereas the levels of PFOS remained steady over the studied period. The PFOS isomer pattern in pilot whale liver was relatively constant over the sampling years. However, in ringed seals there seemed to be a decrease in linear PFOS (L-PFOS) with time, going from 91% in 1984 to 83% in 2006.
Resumo:
Volcanogenic sediments were obtained from Site 584, located on the midslope of the Japan Trench. Occurrences of volcanic ash in the diatomaceous mudstones increase within sediments dated 6-3 Ma. The frequency pattern and the sediment accumulation rate obtained at Site 584 are similar to those of Site 440 and to those of Sites 438 and 439, located on the upper slope basin. Explosive volcanism increased during the Pliocene and late Miocene in relation to the intrusion of Tertiary granites and uplift of the Tohoku Arc (northeastern Japan Arc). Hygromagmaphile element concentration shows that the glass does not belong to a unique series, and a comparison with Nankai Trough data distinguishes at least two different evolutionary lines.