RESUMO
Radiocarbon dating of the carbonate binder of historical mortars is a strategic research topic not lacking in complexities. The critical step is the separation of anthropogenic CaCO3-binder from other carbonate sources that could severely affect the resulting dates. Here we present a complete procedure for the processing and characterization of difficult mortars and of the separated binder fractions in order to assess a priori the chances of positively dating the mortar, and produce a binder fraction yielding the most reliable radiocarbon dates possible. Two complex architectural case studies from Northern Italy are presented and discussed in detail: the churches of Santa Maria Maggiore (Lomello, Pavia) and Santa Maria (Torba, Varese). The results support that both the reliability assessment and the successful radiocarbon dating are possible through a multi-analytical approach encompassing mineralogical and petrographic characterization, X-ray powder diffraction, scanning electron microscopy, measurement of carbon and oxygen stable isotopes, and optical cathodoluminescence.
Assuntos
Carbono , Datação Radiométrica , Carbonatos , Isótopos de Oxigênio , Datação Radiométrica/métodos , Reprodutibilidade dos TestesRESUMO
Evans syndrome is a chronic and recurrent disease often resistant to multiagent therapy. Spontaneous intracranial hemorrhage is a rare but life-threatening complication in children with Evans syndrome. The authors report the fatal course of a child with chronic thrombocytopenia who presented a spontaneous intracranial hemorrhage. The case indicates that this potentially fatal event may occur even in children with a moderate grade of chronic thrombocytopenia. Early recognition and aggressive management is required for an adequate management of this rare complication.
