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Correction factors for magnetic susceptibility measurements on thin (<c. 50 mm thick > artefacts have been determined experimentally for a KT‐5 Exploranium G S. instrument using prepared blocks of Whin Sill dolerite. The cor rection factor is large (> 1.4) for samples less than 10mm thick, and reduces to 1 01 for samples of 50mm thickness. Measurements on thin samples can also be affected by the backing or substrate material on which they are measured. ‘Background’material, for example, soil or plaster, can contribute significantly to recorded measurements on artefacts, particularly for thin artefacts with low susceptibilities  相似文献   

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ARTEFACTS     
《Acta Archaeologica》2012,83(1):231-234
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This study discusses the relevance of compositions obtained using laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) for the purpose of identifying the provenance of copper‐based artefacts found in Virginia at Native American sites dated from the 16th to the 18th centuries. Ten artefacts were investigated by scanning electron microscopy – energy dispersive spectrometry (SEM–EDS) to visualize the corrosion and characterize the heterogeneities in the metal and electron probe micro‐analysis (EPMA) to determine separately the compositions of the intact metal and of the corrosion product. It is shown that the corroded surfaces are highly depleted in zinc but that representative concentrations can be determined by sampling the deeper, uncorroded metal. In contrast, lead values are highly variable because of the heterogeneous distribution of this metal within the bulk copper. Despite these problems, brass is easily identifiable and American native copper and European smelted copper can be unambiguously distinguished with LA–ICP–MS on unprepared artefacts using As, Ag, Ni and Sb trace elements.  相似文献   

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Petar  Zidarov 《Acta Archaeologica》2005,76(1):124-131
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Everyday knowledge – body knowledge – knowledge of experience – specialized knowledge: Acquisition, assessment and the orientation of logic concerning cultures of knowledge. – The essay explores changes in the understanding, legitimisation, and practice of midwifery. It was one of the earliest professional activities for women. During the eighteenth century a new culture of expertise emphasized theoretical knowledge and adherence to medical disciplines over the empirical practice gained by women. This early phase of professionalisation, with its hierarchies and preferred use of medically accredited knowledge, was not, however, solely divided along gender lines. Female professionalism was not just supplanted by male academic medicalisation. New ways of attaining and assessing knowledge, a different perception of how it is organised, and above all, social change created new patterns of understanding. This process achieved a new professional ethos. In pursuing the issue of gender, various examples are chosen to illustrate how changes in scientific knowledge and its relevant application are mediated. The construct of scientific knowledge and how it is used reflects gender relations and power structures. There is not only competition between female and male perceptions of knowledge, but also male stereotyping of female knowledge, in particular male notions of what kind of knowledge is necessary and how this is perceived by women. Karen Offen used the term ‘knowledge wars’ to describe how a monopoly of scientific expertise and relevant knowledge works within the professions.  相似文献   

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The geological sources of obsidian in the Red Sea region provide the raw material used for the production of obsidian artefacts found in prehistoric sites on both sides of the Red Sea, as far afield as Egypt, the Persian Gulf and Mesopotamia. This paper presents the chemical characterization of five obsidian geological samples and 20 prehistoric artefacts from a systematically excavated Neolithic settlement in highland Yemen. The major element concentrations were determined by SEM–EDS analysis and the trace element concentrations were analysed by the LA–ICP–MS method, an almost non‐destructive technique capable of chemically characterizing the volcanic glass. A comparison of archaeological and geological determinations allows the provenance of the obsidian used for the Neolithic artefacts to be traced to definite sources in the volcanic district of the central Yemen Plateau.  相似文献   

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The article reflects on the distinguished record of publication, in around 130 articles over nearly seventy years, on nuclear politics in International Affairs. Although constituting a small drop in the torrent of writings on nuclear matters since 1945, it can fairly be regarded as the most significant contribution to nuclear discourse by any journal outside the United States. The articles published in International Affairs have covered a wide range of issues including nuclear deterrence and strategy, arms control, non‐proliferation and disarmament, and the policies—and drivers of policy—of countries, in particular the UK and US. Authors have included P. M. S. Blackett, Wyn Bowen, Alastair Buchan, Hedley Bull, Pierre Hassner, Michael Howard, Rebecca Johnson, Michael MccGwire, Michael Quinlan, Nick Ritchie, John Simpson and David Yost. The discussion concludes with Ian Smart's article of 1975 in which he contemplates the nature of the ‘nuclear age’ and its persistence or passing, and comments on governments’ ‘fatuous’ attachment of prestige value to nuclear weapons.  相似文献   

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