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Andrew I. Duff Jeremy M. Moss Thomas C. Windes John Kantner M. Steven Shackley 《Journal of archaeological science》2012
X-ray fluorescence analysis of obsidian artifacts from sites located in Chaco Canyon and from three Chaco-era communities in New Mexico permits determination of their geological origin. These source data are used to describe patterning in obsidian procurement in sites located in Chaco Canyon dating from A.D. 500–1150, and in a three non-Canyon communities occupied during the period of Chaco Canyon's regional prominence (ca. A.D. 875–1150). These data demonstrate that the most proximate sources generally dominate the sourced obsidian assemblages from sites of all periods, but also suggest differences in procurement patterning both over time and across space. Within Chaco Canyon, there is a notable shift from Mount Taylor obsidian to use of Jemez Mountains sources over time. These data also suggest that earlier analyses of obsidian from sites in Chaco Canyon misidentified some obsidian artifact sources; these new data indicate the central areas of disagreement and provide a revision of procurement patterning. In the Chaco-era communities located outside Chaco Canyon, procurement patterning diverges. The Blue J community shows an increase in use of the nearby Mount Taylor source over time. Two communities located toward the southern extent of the Chaco great house distribution reveal a markedly distinct procurement pattern, obtaining nearly all of their obsidian from southern sources largely unrepresented at Chaco Canyon. Combined, these data provide new insights into raw material procurement and artifact production at sites in Chaco Canyon, and in communities occupied during the Chaco Phenomenon, the period of the Canyon's greatest regional influence. 相似文献
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Low temperature (90–190 °C) hydrothermal experiments have been conducted on seven obsidians where composition of the glass varies significantly in the concentration of structural water within the unhydrated bulk material. Infrared transmission spectroscopy was used to track the diffusion of molecular water into the glass surface as a function of time and temperature. Long-term (60–360 days) hydration sequences at 90 °C show a t0.6 time dependence for the mass uptake of molecular water that forms the hydration layer. The structural water concentration of the unhydrated bulk obsidian is highly correlated with the pre-exponential and activation energy and may be used to estimate the Arrhenius constants. In addition, secondary ion mass spectrometry (SIMS) hydrogen profiling of Napa Glass Mountain obsidian hydrated at 90 °C reveals that the early stages of diffusion exhibit a dynamic behavior that includes a fluctuating hydrogen concentration and a changing diffusion coefficient that slows with time. 相似文献
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Ricardo Fernandes Geert Geeven Steven Soetens Vera Klontza-Jaklova 《Journal of archaeological science》2011
This paper introduces GIS-based statistical methods for the study of settlement patterning in an archaeological context. The main aspect is an improvement over suboptimal stepwise statistical model selection procedures, with the introduction of a Deletion/Substitution/Addition (DSA) algorithm, a systematic model selection algorithm that provides an optimal model choice. The paper also introduces the combined use of Receiving Operator Characteristic (ROC) curves, and variable ranking as key tools aimed at an understanding of settlement patterning causation. An illustrative case study is provided whereby both a purely environmental and a mixed environmental/historical model (based on settlement hierarchy considerations) are investigated. 相似文献
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Steven R. Holloway 《Social & Cultural Geography》2013,14(2):197-208
Traditional research in urban geography concerned with issues of 'race' has focused on a series of substantively important issues, yet with conceptual foundation inadequate to the task. Specifically, this body of work has employed outdated and theoretically limited conceptions of identity without sufficient consideration to the importance of historical and geographic contingency. I argue in this essay that topics of traditional concern to urban geography gain new relevance and importance when they are reconsidered and reworked from a social constructivist perspective that takes seriously the importance of identity and contingency. I illustrate my argument with discussions of two aspects of my current research agenda. First, I discuss how research on urban residential segregation gains considerably from a more sensitive encounter with multifaceted notions of identity that explicitly address geographic contingency. Second, I review recent empirical research on US mortgage-lending markets that demonstrates the geographic and class contingency of discrimination. The paper ends with a call for research that employs multiple methodologies. 相似文献
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Steven Cassedy 《Journal of the history of the neurosciences》2013,22(4):405-432
The term stimulus, as it was used in science from its earliest appearance in the sixteenth century up to the beginning of the nineteenth century, shows a gradual progress in denotation from the physical object designed to produce nervous and muscular excitation to the generically conceived event or object that initiates sensory or motor activity. To this shift corresponds a shift in the understanding of sensory experience. Johannes Müller's law of specific energy of sensory nerves played a major role in the shift, and Hermann von Helmholtz gave the shift its most thorough philosophical explanation. 相似文献
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