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Zanolli C Bondioli L Mancini L Mazurier A Widianto H Macchiarelli R 《American journal of physical anthropology》2012,147(3):472-481
Currently, the human deciduous dental record from the Pleistocene deposits of the Sangiran Dome, Java, consists of only eight specimens. Here we report two deciduous crowns collected near the village of Pucung. While their precise geo-chronological context remains unknown, a provenance from the Early-Middle Pleistocene Kabuh Formation, or from the Early Pleistocene "Grenzbank Zone," is very likely. These isolated specimens consist of an upper first molar (PCG.1) and a lower second molar (PCG.2). Taxonomic discrimination of the Indonesian tooth record is difficult because of the convergence in crown size and appearance between Pongo and Homo. Accordingly, as PCG.2 still bears a concretion masking most of its features, we coupled the outer analysis of the two specimens with an investigation of their inner morphology. In addition to external characteristics, virtual imaging and quantitative assessment of inner morphology and tissue proportions support an attribution to the taxon Homo, and we preliminary allocate both specimens toH. erectus. 相似文献
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Under high rainfall conditions on acid soils with shallow crop root systems the rate of N leaching is high. A simple model
predicts nitrogen uptake efficiency as a function of the amount of rainfall in excess of evapotranspiration, rooting depth
and degree to which N leaching is retarded in comparison with water transport. Field observations on acid soils in S.E. Nigeria
and S. Sumatera (Indonesia) showed that this model should be amended to include the role of old tree root channels. Crop roots
can follow these channels, which are coated with partly decayed organic matter, into the acid subsoil. Measurements of water
infiltration with a Guelph permeameter and a methylene blue dye showed that such channels form the major infiltration sites
during rainstorms. Implications for nitrogen use efficiency and cropping pattern are discussed. 相似文献
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