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Sharon L. Weinberg Peter G. Bryant Glenn W. Milligan Richard Church A. D. Gordon Gildas Brossier Brigitte Escofier Kathleen M. Carley Frank Critchle 《Journal of Classification》1989,6(1):121-161
Affiliated to Astrophysics Div., Space Science Department, European Space Agency. 相似文献
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Brunet M Guy F Pilbeam D Mackaye HT Likius A Ahounta D Beauvilain A Blondel C Bocherens H Boisserie JR De Bonis L Coppens Y Dejax J Denys C Duringer P Eisenmann V Fanone G Fronty P Geraads D Lehmann T Lihoreau F Louchart A Mahamat A Merceron G Mouchelin G Otero O Pelaez Campomanes P Ponce De Leon M Rage JC Sapanet M Schuster M Sudre J Tassy P Valentin X Vignaud P Viriot L Zazzo A Zollikofer C 《Nature》2002,418(6894):145-151
The search for the earliest fossil evidence of the human lineage has been concentrated in East Africa. Here we report the discovery of six hominid specimens from Chad, central Africa, 2,500 km from the East African Rift Valley. The fossils include a nearly complete cranium and fragmentary lower jaws. The associated fauna suggest the fossils are between 6 and 7 million years old. The fossils display a unique mosaic of primitive and derived characters, and constitute a new genus and species of hominid. The distance from the Rift Valley, and the great antiquity of the fossils, suggest that the earliest members of the hominid clade were more widely distributed than has been thought, and that the divergence between the human and chimpanzee lineages was earlier than indicated by most molecular studies. 相似文献
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Gildas Brossier 《Journal of Classification》1994,11(1):37-58
We consider dissimilarities which are defined only on some pairs of items. Such situations may occur in some problems like unfolding or merging, or can be encountered as an intermediate step of a more general transformation. We give necessary and sufficient conditions for the existence of extensions with good properties and characterize the family of such extensions. Using partial dissimilarities we construct a dissimilarity-into-distance transformation family.The author thanks the editor and two anonymous referees for their suggestions and their helpful comments. 相似文献
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Piecewise hierarchical clustering 总被引：1，自引：0，他引：1
Gildas Brossier 《Journal of Classification》1990,7(2):197-216
We consider two or more ultrametric distance matrices defined over different, possibly overlapping, subsets. These matrices are merged into one ultrametric matrix defined over the whole set. Necessary and sufficient conditions for uniqueness of the merging are established. when these conditions are not satisfied, consistent algorithms are given.The author thanks B. Monjardet and two anonymous referees for their helpful comments. 相似文献
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