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361.
Alterations induced during the first step of fossilization are examined. Molars and premolars of a modern large mammal were crushed to expose fresh dentine. Fragments were placed in solutions of acids present in humus for 2 months. Changes in composition of the solutions were analysed. Micro‐ and nanostructural changes of fresh and etched dentine were observed with scanning electron and atomic force microscopes. The ion contents of the acetic acid solution are higher than those of oxalic and oxalic plus acetic acid solutions. Oxalic acid etching results in secondary deposits of oxalates on the exposed dentine. The composition of the soil in natural fossilization processes is a main factor in fossil preservation. 相似文献
362.
Y. Abd El‐Rahman A. A. Surour A. H. W. El Manawi M. Rifai A. Abdel Motelib W. K. Ali A. M. El Dougdoug 《Archaeometry》2013,55(6):1067-1087
Old mining and smelting features in the Abu Gerida area have been studied using field observations, microscopy and SEM–EDS to detect the ores that were exploited in antiquity. There are two groups of shafts in the area. The first group encloses secondary copper minerals and is associated with glassy slags containing copper prills. The other group is associated with hematite that was extracted and transferred to a smelting station to the west of the mining site, where iron slags and charcoal fragments are found. These slags are composed mainly of wüstite, fayalite–kirschsteinite and traces of metallic iron. Pottery fragments from this area were dated to the Ptolemaic Period, which may be the age of iron exploitation. Copper might have been exploited earlier. 相似文献
363.
Current conceptualizations of resettlement in China as either voluntary or involuntary are too rigid. New guidelines and policies, particularly around Poverty Alleviation Resettlement (PAR), are emphasizing the importance of voluntarism. Little is known, however, about how the principle of voluntary relocation of villagers has actually been implemented. This study explores this process by examining local implementation and experiences of PAR in Linfen Prefecture, Shanxi. It introduces China's nationwide PAR programme, and then identifies the spatial and temporal characteristics of PAR in Linfen from 1997 to 2010, highlighting the factors that contribute to widespread voluntary resettlement. 相似文献
364.
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366.
This article describes a novel, small-scale nonlinear beam-column connection and an associated six-story frame test structure for the experimental dynamic response investigation of multi-story buildings subjected to earthquake loading. The objective is to create a re-configurable, reusable experimental platform on which several aspects of nonlinear dynamic response can be investigated through successive, exhaustive testing under suites of earthquake records. Static and dynamic calibration tests demonstrate excellent test-to-test repeatability of four structure configurations. These results confirm that the properties of each configuration (period, strength, energy dissipation) remain invariant, thus allowing future experimental investigations (e.g., of peak engineering demands) under earthquake loading. 相似文献
367.
C. Tribolo N. Mercier E. Douville J.-L. Joron J.-L. Reyss D. Rufer N. Cantin Y. Lefrais C.E. Miller G. Porraz J. Parkington J.-P. Rigaud P.-J. Texier 《Journal of archaeological science》2013
Diepkloof Rock Shelter offers an exceptional opportunity to study the onset and evolution of both Still Bay (SB) and Howiesons Poort (HP) techno-complexes. However, previous age estimates based on luminescence dating of burnt quartzites (Tribolo et al., 2009) and of sediments (Jacobs et al., 2008) were not in agreement. Here, we present new luminescence ages for 17 rock samples (equivalent dose estimated with a SAR-ITL protocol instead of classical MAAD-TL) as well as for 5 sediment samples (equivalent dose estimated with SAR-single grain OSL protocol) and an update of the 22 previous age estimates for burnt lithics (modified calibration and beta dose estimates). While a good agreement between the rock and sediment ages is obtained, these estimates are still significantly older than those reported by Jacobs et al. (2008). After our own analyses of the sediment from Diepkloof, it is suspected that these authors did not correctly chose the parameters for the equivalent dose determination, leading to an underestimate of the equivalent doses, and thus of the ages. 相似文献
368.
Christelle Lahaye Marion Hernandez Eric Boëda Gisele D. Felice Niède Guidon Sirlei Hoeltz Antoine Lourdeau Marina Pagli Anne-Marie Pessis Michel Rasse Sibeli Viana 《Journal of archaeological science》2013
When and how did the first human beings settle in the American continent? Numerous data, from archaeological researches as well as from palaeogenetics, anthropological and environmental studies, have led to partially contradictory interpretations in recent years, often because of the lack of a reliable chronological framework. The present study contributes to the establishment of such a framework using luminescence techniques to date a Brazilian archaeological site, the Toca da Tira Peia. It constitutes an exemplary case study: all our observations and measurements tend to prove the good integrity of the site and the anthropological nature of the artifacts and we are confident in the accuracy of the luminescence dating results. All these points underline the importance of the Toca da Tira Peia. The results bring new pieces of evidence of a human presence in the north-east of Brazil as early as 20,000 BC. The Toca da Tira Peia thus contributes to the rewriting of the history of the peopling of the American continent. 相似文献
369.
Lauren M. Cleeland Mason V. Reichard Raul Y. Tito Karl J. Reinhard Cecil M. Lewis Jr. 《Journal of archaeological science》2013
This paper reports an approach to the identification of prehistoric parasitic infection, which integrates traditional morphological methods with molecular methods. The approach includes the strengths of each method while mitigating the limitations. Demonstrating the efficacy of this approach, we provide a case study from a 1400 year old desiccated fecal sample from La Cueva de los Muertos Chiquitos, archaeological site, near Rio Zape, Durango, Mexico. Traditionally prepared microscope slides were processed via microscopy and tentative ascarids were identified. Information regarding the parasites' developmental stage was recorded. DNA was then extracted directly from the slide material. From this DNA extract, a small segment of the 18S ribosomal RNA gene variant that is specific to Ascaris, and its phylogenetically close relatives, was targeted for PCR amplification and sequencing. Phylogenetic analysis of the DNA sequence best matched a member of physalopterids, rather than ascarids, with a single exception of a match to Contracaecum spiculigerum. Subsequent extractions, amplifications and sequencing of the original rehydrated coprolite material confirmed these results. The C. spiculigerum sequence represented a phylogenetic anomaly and subsequent analysis determined the sequence was an error in the BLAST database, likely attributable to misidentification of juvenile specimens prior to sequencing and submission. Physaloptera are a difficult genus to identify morphologically and can carry major health burdens. They may be underreported in humans, in part, because of morphological similarities to the more common human parasites belonging to ascarids. We conclude that integrating traditional morphological methods with molecular methods can help resolve this issue, in both contemporary and prehistoric populations. 相似文献
370.
Y.S. Volkova 《Archaeology, Ethnology and Anthropology of Eurasia》2013,41(3):33-39
Principal stages in the manufacture of zoomorphic, polyiconic, and anthropomorphic Upper Paleolithic figurines are reconstructed. General factors determining their characteristics include universal conventions of representation and the limited set of technological operations available, whereas local factors include specific ways of processing materials and combining artistic techniques, the manner of individual masters, technological faults and accidents, as well as taphonomic processes. 相似文献