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991.
This paper highlights the contribution of transmission electron microscopy (TEM) when combined with scanning electron microscopy and energy‐dispersive X‐ray microanalysis (SEM/XEDS) to characterize objects in archaeology. The application of TEM in archaeology is not yet a common tool, but it may provide data that are significant to understanding pre‐Columbian gold metallurgy, specifically the gilding and silvering methods. Two gilded rods were studied using a combination of TEM and SEM/XEDS techniques. The objects were found at the Atacames archaeological site, in the Esmeraldas region, Ecuador, which was occupied between ad 750 and 1526 by the Atacames culture. The microchemical and structural results of the inner and the external gilded part of the artefacts support the hypothesis of a gold diffusion to the surface enhanced by chemical treatment with chloride‐rich solutions, heating and successive annealing processes. The present study reveals that microstructural investigation by TEM provides useful information with which to investigate the techniques used to modify the chemical surface composition of pre‐Columbian artefacts.  相似文献   
992.
Archaeological excavations carried out in Early Iron Age Vetulonia (northern Tuscany, Italy) brought to light a funerary urn particularly noteworthy for the presence of an unusual decoration obtained by plastering the vase surface with an organic dark grey substance, on which metal strips were originally fixed. In order to reveal the origin of such coating, it was chemically studied by gas chromatography coupled with mass spectrometry (GC/MS). Chemical analysis not only revealed that birch bark tar was used as coating/adhesive material for the manufacture of the urn, but also allowed us to discuss the significance of the vessel in terms of eco‐technological knowledge and possible cultural connections on a large geographical scale.  相似文献   
993.
Primary questions regarding the foraging behaviour of the first hunter–gatherers who colonized the New World are how they found, procured and utilized high‐quality raw materials for manufacturing stone tools. In this paper, we present evidence from the late Pleistocene site of Cueva Bautista in the highlands of south‐western Bolivia, which demonstrates that a substantial portion of the recovered stone tool assemblage originated in Cerro Kaskio, a recently discovered obsidian source located 15 km south‐west of the site. In addition to describing the geological and geochronological setting, we provide the first geochemical characterization of the Cerro Kaskio source by means of instrumental neutron activation analysis and energy‐dispersive X‐ray fluorescence. Supported on the technological analysis and archaeometric sourcing of the obsidian lithics found in Cueva Bautista, we discuss the nature of the procurement strategies practised by the earliest mobile hunter–gatherers who explored and colonized the Andean highlands. We conclude that opportunistic lithic resource procurement was probably an important component of the first foraging societies that explored the highland Andes.  相似文献   
994.
995.
The pillar of fire was a unique phenomenon that led the Israelites at night through the wilderness for forty years. Many theories have been offered to explain this phenomenon such as it was mythical or metaphorical and never occurred. Other explanations include burning jets of natural gas, a brazier elevated on a pole, volcanic activity, brush fires, lightning, and a comet. The large and controlled shape of the pillar of fire, its appearance only at night for forty years, and its carefully directed path have been explained as miraculous. This article includes a scientific discussion of how the pillar might have been produced, reviews the many theories offered to explain the pillar of fire, and offers several new theories.  相似文献   
996.
997.
This paper examines conceptual and methodological issues in the analysis of environmental justice through use of the case of lead-exposure health risks. Researchers face important obstacles in measuring variable risks among population subgroups. The case of lead exposure, however, illustrates the dramatic potential where adequate data exist for identifying and correcting significant inequities in risk exposure. Despite sharp reductions in the general population's exposure to lead since the 1970s, substantial numbers of minority and low-income children continue to exhibit unacceptably high blood-lead levels due primarily to exposure to lead-based paint. Resolving environmental inequities in this and similar instances requires solid documentation of the risk and better integration of equity issues with other policy demands such as the call for cost-effective environmental policy.  相似文献   
998.
Marilyn E. Lashley and Melanie Njeri Jackson (Eds.), African Americans and the New Policy Consensus: Retreat of the Liberal State.  相似文献   
999.
1000.
Archaeologists are increasingly becoming aware of an approach to data investigation known as Bayesian statistics. In this paper we outline both the philosophical and statistical background to the approach. We show that it provides a logical and coherent framework in which to make inferences on the basis of both data and a priori expert knowledge. We note that adoption of the Bayesian framework is particularly timely since there have been recent dramatic developments in numerical methods which mean that a number of previous implementation problems have now been solved. As a result, many questions of archaeological interest, which require the use of complex statistical models, are being investigated using this methodology. We use a variety of recently published examples from a range of archaeological areas to illustrate the type of questions that can be answered and the nature of the methodologies used, and we make comparisons with the results obtained using more traditional statistical techniques.  相似文献   
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