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71.
Recognition,Sovereignty Struggles,and Indigenous Rights in the United States: A Sourcebook. Edited by Amy E. Den Ouden and Jean M. O'Brien. (Chapel Hill,NC: University of North Carolina Press, 2013. Pp. 376. $26.95.)
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Tim Alan Garrison 《The Historian; a journal of history》2015,77(4):784-785
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The study analysed pre-Hispanic gold objects found within a surprising archaeological finding of a structure that likely served as a funeral pyre in Medellín, Colombia. 14C analyses of the site's organic materials dated the structure to the fifth century ce . The metal objects were subjected to X-ray diffraction (XRD), energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), density measurement by the Archimedes method, and metallographic analysis. The measurements by EDXRF and SEM-EDX showed that the pieces were composed mostly gold and silver. The XRD results indicated that the microstructure of the objects corresponded to a single phase of gold and silver. The images obtained by the metallographic microscope showed equiaxial grains with some twins, a structure consistent with annealed metals. The different colours observed correspond to different grain orientations. Pre-Hispanic objects from a second archaeological site in the municipality of Amalfi (Department of Antioquia) were also analysed for comparative purposes. The results showed that the gold objects were not subjected to any alloying process, but were instead manipulated in their original form (native gold). The shape of the objects and their microstructural results suggested that the pieces were manufactured by casting, mechanical deformation and then annealing. 相似文献
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Five unidentifiable, completely corroded ancient coins (three of which were large fragments), proven to lack any residual internal metal, were scanned by nano-computed tomography (CT) to see if discernible detail might still be present. One fragment could be identified as an early fourth-century Urbs Roma commemorative AE 3/4. Another fragment was a coin of either Valerian or of the joint rule of Valerian and Gallienus, which could be dated to the period 254–56 ce . The other three lacked discernible detail. This proof-of-concept study shows that nano-CT scanning has the potential to allow non-invasive identification of at least some totally corroded coins. 相似文献
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The study analyses the chemical composition of 57 glass samples from 40 beads discovered at 20 archaeological sites in Poland. The beads are dated to Hallstatt C–Early La Tène periods (c.800/750–260/250 bce ). Analyses were carried out using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Two groups were distinguished among the glasses based on the MgO/K2O ratio: high-magnesium glass (HMG), five samples; and low-magnesium glass (LMG), 52 samples. The former were melted with halophyte plant ash, the second with mineral soda. These glasses were produced in the Eastern Mediterranean (more likely in Mesopotamia or Syro-Palestine than in Egypt) and transported in the form of semi-products to secondary glass workshops in Europe. Some of the white opaque glass was coloured and opacified in Europe. 相似文献
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The Te Kawa a Māui Atlas project explores how mapping activities support undergraduate student engagement and learning in Māori studies. This article describes two specific assignments, which used online mapping allowing students to engage with the work of their peers. By analysing student evaluations of these activities, we identify four aspects that benefit student engagement: mapping diversifies the learning experience; mapping promotes acquisition of a different skill set; online mapping allowed more open sharing of work and; mapping promotes place-based learning. Some students were ambivalent about the assignments, so mapping should only be used to support other learning objectives. 相似文献
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