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Oxygen is a key parameter in the degradation of archaeological material, but little is known of its dynamics in situ. In this study, 10 optical oxygen sensors placed in a 2 m deep test pit in the cultural deposits at Bryggen in Bergen have monitored oxygen concentrations every half hour for more than a year. It is shown that there is a significant spatial and temporal variation in the oxygen concentration, which is correlated to measured soil characteristics, precipitation, soil water content and degradation of organic material. In these deposits oxygen typically occurs when the air content of the soil exceeds 10–15% vol, while oxygen dissolved in infiltrating rainwater is of less importance for the supply of oxygen in the unsaturated zone.  相似文献   
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Twenty‐six samples from domestic assemblages of 9th–12th century Córdoba were subjected to electron microprobe analysis. The results reveal two main compositional types. The first, encountered in 13 of the samples, seems to result from the combination of plant ashes with high‐impurity sand, and has some contemporary parallels from Syria and Egypt. The second type is a lead–soda–silica glass, encountered in a relatively high proportion of the glasses (11 of the 26 sampled), possibly formed by the addition of lead metal to existing glasses and with very few known parallels. These are among a very small number of results available to date on the chemical composition of glasses from medieval Spain, and the presence of a high proportion of lead–soda–silica glasses is particularly interesting, possibly indicating a technological practice unique to, or originating in, the western Muslim world.  相似文献   
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This paper compares left-wing Latin American populism with Donald Trump. Despite their different social bases and economic policies, they use a similar logic to construct politics as an antagonistic struggle between two camps. Left-wing and right-wing populists aim to rupture existing political institutions to give power to the people, yet they differ in how they construct this category. Whereas Trump used ethnic criteria to differentiate the people from three out groups – Mexicans, Muslims, and African-American militant organisations – left-wing Latin American populists used political and socio-economic criteria. Despite their democratising promises, Latin American populists like Hugo Chávez in Venezuela and Rafael Correa in Ecuador undermined democracy from within. Even though stronger institutions might protect American democracy, Trump has disfigured democracy.  相似文献   
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Jan Turek 《Archaeologies》2017,13(3):535-548
Sadly, aggression is still one of the most common features of human behaviour; it is an instinct to promote and survive our own genes against the genes of others. Human intraspecific aggression has gradually become part of human culture over the last 40,000 years and has been institutionalized in various forms of social activities. Particularly in the post-glacial period, the level of social relations has developed dramatically in the context of population growth and the growth of human communities. In the time of Neolithic and Chalcolithic European agricultural populations, the motive of control over farming land became highly important. Also the control of main means of production and social power was increasingly maintaining the intragroup competition and aggression. Thus, violence was employed within the community in order to obtain and maintain individual or collective social status, but also against other communities in an effort to protect property and territory. Particularly the intracommunity aggression was soon transformed into variety of different formal ways of symbolic fighting, which usually did not lead to the unwanted death of a defeated member of the community. The symbolic struggle between members of the community as well as the defense against external aggression were gradually formalized in the form of introduction of specialized weapons designed for combat between people and creation of fortifications. During the Neolithic period a new phenomenon arose in human culture: warfare.  相似文献   
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