We present the detailed analysis of a cervical vertebra from a cave bear, found at Pešturina cave, Serbia, in a Mousterian archaeological level dated by radiocarbon at 43.5-44.6 kyr cal BP, and by ESR to between 93.5 and 102.5 kyr BP. Identified as a portion of the cranial articular facet, the fragment displays ten subparallel grooves. The microscopic study of these grooves and other surface modification present on the bone fragment, conducted with multifocus optical and confocal microscopes and complemented by a taphonomic analysis of the associated faunal assemblage, supports the hypothesis that the incisions were made by humans. Results are used to critically examine ambiguities implicit in the analysis and interpretation of early engravings, a category of material culture that has been playing a key role in the identification of early instances of symbolically mediated behavior.
If {A t } t∈Ω and {B t } t∈Ω are weakly*-measurable families of bounded Hilbert space operators such that transformers X → Ω A * t XA t dµ(t) and X → Ω B * t XB t dµ(t) on B(H) have their spectra contained in the unit disc, then for all bounded operators X If at least one of those families consists of bounded commuting normal operators, then (1) holds for all unitarily invariant Q-norms. Applications to the shift operators are also given.
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