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91.
92.
The newly developed lexsyg system by Freiberg Instruments is a versatile luminescence reader, suited for research on the luminescence of materials, fundamental research in luminescence dating, but also for routine mass measurements in retrospective dosimetry as well as in dating application. The 80 sample storage wheel is disconnected from the measurement chamber and therefore crosstalk of optical stimulation is absent and cross-irradiation is negligible from the α- and β-sources, which are providing very uniform irradiations, with the latter especially designed for radiofluores-cence (RF) measurement. Optical excitation sources and filter wheels to vary detection wavelengths can be programmed to change at almost any time within measurement sequences, including the auto-mated change of an optional wheel holding up to four different detectors. Thermoluminescence meas-urements and preheating are possible with a versatile heater, which can be programmed for linear or non-linear heating or cooling, as well as holding a temperature constant. Rates as well as durations can be varied, together with individual ramping, staging and cooling for an almost unlimited number of steps. Violet- and IR-lasers, green and blue LED-arrays can be operated in continuous (CW) or modulated mode (linear/non-linear), and optionally for pulsed as well as time resolved luminescence detection. Six arrays of power LEDs allow the simulation of different bleaching regimes (‘solar simu-lator’), while luminescence detection can be achieved by a variety of photomultiplier tubes and by CCD cameras for spatially resolved measurements and luminescence spectra. 相似文献
93.
Linda Egan 《Romance Quarterly》2013,60(2):116-128
Carlos Fuentes's 1987 carnivalesque novel, Cristóbal nonato, criticizes Mexico's prehispanic past through a satire of Tenochtitlán-Mexico City in the neoliberal, postnational era. This study consequently juxtaposes criticism, theory, and analysis from both imperial Aztec Mexico and nationalist modern Mexico. While the bulk of this 600-page novel confronts readers with a highly negative (although often risible) view of both Mexicos, it ultimately leads to a happy ending with a didactic twist: If Mexicans will stop abandoning Mexico for the North or other green pastures, and instead stay in Mexico despite its many problems, they can turn things around by their altruism and their activist determination. 相似文献
94.
The story of the Navajo Nation and uranium mining is, at itsheart, a tale of environmental justice. From the late 1940suntil the 1960s, uranium mining by private corporations whosesole purchaser was the federal government, employed Navajosto work the mines in the Four Corners area. When the uraniumboom ended, the miners and their families were left with hugepiles of uranium tailings, compromised health, and a scarredlandscape. The Navajo People and Uranium Mining fills a crucialchapter of this story in a short, yet powerful work that illuminatesthe ongoing social, psychological, and environmental problemsrelated 相似文献
95.
Kevin J. Edwards Graeme Whittington Marie Robinson Daniela Richter 《Journal of archaeological science》2005,32(12):1741-1756
The Loch of Clickimin, Shetland, is well known for its broch and associated monuments supposedly of the Bronze and Iron Ages, although the former date is disputed. Pollen, diatom and sedimentological investigations permit fresh insights into the landscape and economic impacts of those who constructed the monuments, reveal that the environs of the site experienced environmental change from Neolithic times onward and provide the first Holocene radiocarbon dates from the immediate locality. The broch-building period witnessed a continuation of pre-existing pastoral husbandry for which heather burning may have exacerbated the natural spread of blanket peat. Initially, no evidence was adduced for local arable activity in the present investigation, and this was thought to be consistent possibly with the low numbers of excavated querns and the absence of cereal macrofossil finds when compared with other Shetland broch sites. The application of ‘rapid scanning’ techniques, however, led to the discovery of a consistent cereal-type pollen representation from Bronze Age times onwards. The discrepancies between the palaeoenvironmental evidence and the environmental and palaeoeconomic inferences made by the excavator of the site are explored. Evidence is presented that both supports and contradicts previous assumptions surrounding an important archaeological site. 相似文献
96.
Non-destructive chemical characterization of ceramic sherds from Shipwreck 31CR314 and Brunswick Town, North Carolina 总被引:1,自引:0,他引:1
Lisa S. Schleicher J. William Miller Sarah C. Watkins-Kenney Linda F. Carnes-McNaughton Mark U. Wilde-Ramsing 《Journal of archaeological science》2008,35(10):2824-2838
The purpose of this study was to chemically and texturally characterize ceramic oil jar sherds from North Carolina Shipwreck 31CR314 and to explore the utility of environmental scanning electron microscopy/X-ray energy dispersive spectrometry (SEM/EDS) for that purpose. The oil jar sherds, widely dispersed about Shipwreck 31CR314, are morphologically similar to each other, which suggests they could be from a single jar, but with so few joins this could not be concluded with certainty. Therefore, an aim of this study was to investigate whether chemical or textural characterization of the sherds might reveal unique attributes that could distinguish individual jars; results of characterization perhaps could give information on their origin and possibly site formation processes, such as whether environmental forces could have scattered sherds of a single jar during and after sinking of the ship. Previous studies have indicated this shipwreck is likely the remnants of the Queen Anne's Revenge, flagship of the pirate Blackbeard. Sherds from this shipwreck were compared with similar oil jar sherds excavated from a land site, Brunswick Town, North Carolina, to explore the use of composition and texture as hallmarks. The chemical components of the artifacts were determined by SEM/EDS. This method of analysis is valuable for archaeological research because it is rapid and non-destructive to the ceramic artifacts. Both groups of lead-glazed coarse red earthenware sherds were texturally similar except for the glazed sides of all 31CR314 sherds that exhibited small tracks of unique crescent-shaped marks. These marks may be due to manufacturing effects and immersion in seawater, and the marks may serve as hallmarks for individual jars or potentially individual manufacturers. The sherds were generally similar in composition, but the two groups exhibited distinct differences. Brunswick Town sherds consistently contained more phosphate on unglazed sides, an average 1.46 wt.% P2O5, and also contained trace elements not detected in the Shipwreck 31CR314 sherds. These distinct differences could be due to different manufacturing origins for Shipwreck 31CR314 and Brunswick Town ceramics but also could reflect their subjection to different environments during use and loss prior to archaeological recovery. 相似文献
97.
Ethnoarchaeological research at highland Maya hunting shrines documents the material remains of interactions between two types
of animate beings: humans and the forest. When either active agent enters the others’ domain there are accompanying ceremonial
activities to assuage the inherent danger, often leaving physical traces in the material record. These traces, if found in
the archaeological record, might reveal similar ancient interactions. Using the material correlates of modern hunting rituals,
we explore the utility of ethnoarchaeological research in identifying negotiations with non-human agents associated with the
animate forest – an active agent in many societies. 相似文献
98.
Eva Siekierska Richard Labelle Louis Brunet Bill Mccurdy Peter Pulsifer Monika K. Rieger Linda O'Neil 《The Canadian geographer》2003,47(4):480-493
Thanks to advances in technology such as Internet-based mapping and the development of special inks, papers and global positioning systems, map making for vision impaired people can provide a range of products (e.g., tactile, haptic and audio-tactile maps) that can improve their independence, self-confidence and everyday life. The applications of tactile maps include learning spatial concepts and geography; audio-tactile maps combined with access to geospatial information can enhance mobility and independence. In 1998, the Mapping Services Branch (MSB) of the Earth Sciences Sector of Natural Resources Canada initiated a tactile mapping program. Now referred to as the Government on Line—Mapping for the Visually Impaired Project (Natural Resources Canada 2003a), it aims to serve the community with special needs, with emphasis on those who are blind or visually impaired, their teachers and mobility instructors. This technical paper discusses the various types of tactile and audio-tactile maps of Canada developed by the MSB in cooperation with its partners and describe the current research and development activities carried out within the project. It also leads the reader to further information on audio-tactile maps and touch- and sound-based computer interfaces. 相似文献
100.