Global aridity synthesis for the last 60 000 years
Abstract. A compilation of published literature on the dust content in terrestrial and marine sediment cores are synchronised on the basis of pollen data and speleothem growth phases within GICC05 age constrain. Based on that, aridity patterns for ten key areas in the global climate system are reconstructed over the past 60 000 years. These records have different time resolutions and rely on different dating methods, thus of various types of stratigraphy. Nevertheless, all regions show humid conditions during the early MIS3 and early Holocene, but not always of the same timing. Such discrepancies have been interpreted as regional effects while also due to stratigraphical uncertainties. In c…
Four new eremophilendiolides from Ligularia atroviolacea
From Ligularia atroviolacea, four new eremophilendiolides, 8 beta-hydroxy-eremophil-3,7 (11)-dien-12,8 alpha(14,6 alpha)-diolide (1), 8 beta-methoxy-eremophil-3,7(11)-dien-12,8 alpha(14,6 alpha)-diolide (2), 8 alpha-hydroxy-eremophil-3,7(11)-dien-12,8 beta(14,6 alpha)-diolide (3) and eremophil-3,7(11),8-trien-12,8 (14,6 alpha)-diolide (4), as well as a known diolide (5) were isolated. Their structures were elucidated on the basis of 1D and 2D NMR as well as ESI-MS spectral data. (c) 2006 Yu Zhao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.