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91.
Archaeological bones, found close to Mexico City (Tlatelcomila), with alterations due to probable thermal exposure attributed to a possible case of cannibalism, have been characterized by XRD, SAXS and SEM. It is shown how these non‐destructive techniques, which are not conventionally used in archaeological research, may provide useful information. The deterioration degree of the bone structure is quantified through parameters such as gyration radius or fractal dimension. As some of the reported modifications could be attributed to diagenesis, a discussion is presented in terms of bone crystallinity and ionic exchange. Furthermore, the hydroxyapatite crystallite size increased depending on colour: this feature is not explained by diagenesis—it can only be attributed to temperature. We conclude that the samples were thermally treated. Indeed, thermal treatment alters the structure and morphology of bone at a very fine level (microscopic and nanometric), while morphology follows the structural modifications. It is determined that the studied human bones were treated at three different temperatures close to 100, 250 and 600°C. Therefore, they were either boiled (barbacoa) or grilled. 相似文献
92.
Travertine was one of ancient Egypt's most popular ornamental stones. Upon prolonged exposure to sunlight, the rock's translucent brownish calcite is bleached to nearly white. Ultraviolet and gamma irradiation experiments were undertaken to investigate the source of the brownish colour and the process by which it fades. It was found that the coloration results from the activation of colour centres by natural radioactivity within the rock, and that these colour centres are deactivated by the ultraviolet component of sunlight. The results also demonstrate that the original brownish colour of sun‐bleached, travertine objects can be restored by artificial gamma irradiation. 相似文献
93.
I. K. BAILIFF 《Archaeometry》2007,49(4):827-851
Fired clay brick samples, obtained from a group of seven high‐status late‐medieval and post‐medieval buildings in England ranging in age from c. ad 1390 to 1740, were dated by the luminescence method using an optically stimulated luminescence (OSL) technique. The results obtained indicate that, when applied to quartz extracted from brick, the technique is capable of producing dates that are in consistently good agreement with independent dating evidence for the buildings. For six samples taken from a group of four dating ‘control’ buildings the mean difference between the central values of luminescence and assigned ages was 5 ± 10 years (SD, n = 6). The methodology used is appropriate for application to other standing buildings in other temporal and geographic regions, and may be used with confidence where conventional dating methods are less certain. The study also examines the luminescence characteristics of quartz and the characteristics of the lithogenic radionuclides in brick samples and identifies various aspects related to the assessment of experimental uncertainty in testing the reliability of the method. 相似文献
94.
David I. Stern 《政策研究杂志》2007,35(2):291-322
Prior to Mexico's entry to the North American Free Trade Agreement (NAFTA), predictions of the consequent impact on the environment in that country ranged from the dire to very optimistic. This article investigates NAFTA's outcomes in terms of energy use and the emission of atmospheric pollutants. Specifically, has entry into NAFTA led to a convergence or divergence in indicators of emissions, environmental efficiency, and emissions‐specific technology in Mexico, the United States, and Canada? A battery of tests is applied to these indicators for energy use and carbon, sulfur, and NOx emissions in the three countries. The results show that the extreme predictions of the outcomes of NAFTA have not materialized. Rather, trends that were already present before the introduction of NAFTA continue and, in some cases, improve post‐NAFTA, but not yet in a dramatic way. There is strong evidence of convergence across the three countries toward a lower intensity of energy use and emissions per unit of GDP. Although intensity is rising initially for some variables in Mexico, it eventually begins to fall post‐NAFTA. Per capita emissions of sulfur and NOx also show convergence, but this is not the case for energy and carbon, and the latter variables also drift moderately upwards. The state of technology in energy efficiency and sulfur abatement is improving in all countries, although there is little, if any, sign of convergence and NAFTA has no effect on the rate of technology diffusion. However, total energy use and carbon emissions increase both pre‐ and post‐NAFTA and total NOx emissions increase in Mexico. Only total sulfur emissions are stable and falling in all three NAFTA partners. 相似文献
95.
96.
C.M. Nielsen-Marsh C.I. Smith M.M.E. Jans A. Nord H. Kars M.J. Collins 《Journal of archaeological science》2007
We have applied cluster analysis to mercury intrusion porosimetry data from 219 archaeological bones (121 human and 98 animal) and soil chemistry data from 219 accompanying soil samples (1 per bone sample), to investigate the influence of soil chemistry on bone preservation. The samples chosen for the study were obtained from sites ranging in time from the pre-modern to the Mesolithic and were representative of burial environments across Europe (from the Baltic to the Mediterranean). These results represent the single largest database for archaeological bone preservation in the European Holocene to date and demonstrate the potential for large-scale diagenetic studies to help develop long term preservation strategies for our European heritage. Despite the variety of sites and environments, bones could be categorised into only four main diagenetic types. Furthermore, soil chemistry appears to significantly affect only one type of preservation, the pathway characterised by loss of mineral. In neutral to basic soils, taphonomy and in particular the differences between the treatment of human and animal remains, becomes the dominating factor in determining preservation. Using these results, strategies for heritage management of archaeological sites can be suggested; grouping sites into those requiring immediate excavation and those where in situ preservation is viable. 相似文献
97.
During recent reinvestigations in the Great Cave of Niah in Borneo, the ‘Hell Trench’ sedimentary sequence seen by earlier excavators was re-exposed. Early excavations here yielded the earliest anatomically-modern human remains in island Southeast Asia. Calibrated radiocarbon dates, pollen, algal microfossils, palynofacies, granulometry and geochemistry of the ‘Hell Trench’ sequence provide information about environmental and vegetational changes, elements of geomorphic history and information about human activity. The ‘Hell’ sediments were laid down episodically in an ephemeral stream or pool. The pollen suggests cyclically changing vegetation with forest habitats alternating with more open environments; indicating that phases with both temperatures and precipitation reduced compared with the present. These events can be correlated with global climate change sequences to produce a provisional dating framework. During some forest phases, high counts of Justicia, a plant which today colonises recently burnt forest areas, point to fire in the landscape. This may be evidence for biomass burning by humans, presumably to maintain forest-edge habitats. There is evidence from palynofacies for fire on the cave floor in the ‘Hell’ area. Since the area sampled is beyond the limit of plant growth, this is evidence for human activity. The first such evidence is during an episode with significant grassland indicators, suggesting that people may have reached the site during a climatic phase characterised by relatively open habitats ∼50 ka. Thereafter, people were able to maintain a relatively consistent presence at Niah. The human use of the ‘Hell’ area seems to have intensified through time, probably because changes in the local hydrological regime made the area dryer and more suitable for human use. 相似文献
98.
Ipek O¨zbek So¨nmez 《European Planning Studies》2007,15(3):319-338
In Turkey, poverty has been a main subject of debates since 1960s. It used to be a serious problem for both rural areas and the big cities that gained migration. In Turkey and world-wide since the 1980s, however, there have been more research interests in the concentrated urban poverty, especially along with the increase in levels of impoverishment around the world. With the help of a case study in Izmir (Turkey), this paper aims to examine the process of concentrated urban poverty from different points of view in the literature. This is a case study developed at the peripheries of the traditional city centre—or inner areas—of the city of Izmir, Turkey. The paper, first, discusses the parameters of concentrated poverty according to the literature. Then it introduces the study findings of the author, which point out the macro-scale, micro-scale and ecological dynamics that are important in the development of concentrated urban poverty. The macro-scale dynamics suggest that poverty in inner areas of the city are related to the unbalanced development trends within the country, such as the overgrowth of metropolitan cities, economic restructuring processes, migration trends and the development of informal economy. The ecological dynamics address to the housing and job location preferences and invasion-succession processes in the city, which emphasize that socio-economic characteristics of inner areas of the city are different from those of other city parts. Micro-scale dynamics are related to poors' ability of developing solidarity relations among themselves, which is also related to the spatial characteristics of inner areas of the city, according to this study's findings. 相似文献
99.
Increasing Role of Services in Competitive Power and Innovativeness of Firms and Industrial Clusters
The aim of this paper is to discuss the importance of different types of global services for industrial firms and clusters in terms of their economic competitiveness and innovative performance. The theoretical debates argue that globalization, deregulation and the new production organization make it necessary to use global services that are supplied easily with the help of new telecommunication technologies. The existing empirical studies provide some supporting evidence. However, they also indicate that global service firms can be attained by only smaller numbers of industrial firms and clusters. Still, in-house services besides temporal and informal mechanisms are important to meet the needs of the specialized services, even for the firms that try to become a part of the global production system. The paper focuses on three main questions: “What types of global services are becoming crucial for manufacturing firms and what type of services are still local and national? Is there a significant difference between the characteristics of firms that use the same type of services? To what extent is having access to global services important for the innovativeness of industrial firms and clusters? This paper looks for the answers to these questions based on existing case studies as well as this study of three industrial clusters in Turkey. The findings indicate that there is not a perfect match between theory and empirical evidence and there is a need for more refined theoretical discourses on industry–service relations. 相似文献
100.