David Sebag

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Central Africa includes the world's second largest rainforest block. The ecology of the region remains poorly understood, as does its vegetation and archaeological history. However, over the past 20 years, multidisciplinary scientific programmes have enhanced knowledge of old human presence and palaeoenvironments in the forestry block of Central Africa.(More)
Application of Rock-Eval pyrolysis to soil organic matter (SOM) quantitation and characterization has been explored by the study of about 100 soil samples taken from a variety of soil profiles from different ecosystems at different latitudes. A straightforward illustration of these possibilities can be obtained from a Hydrogen Index (HI in mg hydrocarbons g(More)
Since the first suggestion of 1500-year cycles in the advance and retreat of glaciers (Denton and Karlen, 1973), many studies have uncovered evidence of repeated climate oscillations of 2500, 1500, and 1000 years. During last glacial period, natural climate cycles of 1500 years appear to be persistent (Bond and Lotti, 1995) and remarkably regular (Mayewski(More)
A five-day international workshop was recently convened at the Université des Sciences et Techniques de Masuku in Gabon to enhance international collaboration among Central African, US and European scientists, conservation professionals and policy makers. The overall aims of the workshop were to: (1) discuss emerging priorities in biodiversity and(More)
Colour is a fundamental property of sediment and is often used for lithographic description to determine sedimentological structures, facies etc. However, the information contained in this parameter is difficult to extract because it is difficult to quantify. Colour can be quantified by spectrocolorimetry which provides very high resolution data quickly and(More)
(283 articles) health and disease and epidemiology (269 articles) environmental science (535 articles) ecology Articles on similar topics can be found in the following collections Email alerting service here right-hand corner of the article or click Receive free email alerts when new articles cite this article-sign up in the box at the top One contribution(More)
Since the first suggestion of 1500-year cycles in the advance and retreat of glaciers (Denton and Karlen, 1973), many studies have uncovered evidence of repeated climate oscillations of 2500, 1500, and 1000 years. During last glacial period, natural climate cycles of 1500 years appear to be persistent (Bond and Lotti, 1995) and remarkably 5 regular(More)
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