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71.
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
72.
C. N. Duckworth R. Córdoba de la Llave E. W. Faber D. J. Govantes Edwards J. Henderson 《Archaeometry》2015,57(1):27-50
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
73.
Comparative policy studies face a number of methodological challenges where conceptualization of the object of comparison—policy output—is the most fundamental. On the basis of three common approaches of the study of policy output, we reconsider this widely applied concept and propose a refined measure as a function of both density (number of policy instruments) and intensity (content of policy instruments). We theoretically derive six policy‐intensity measures (objectives, scope, integration, budget, implementation, and monitoring), which are used for weighting national policy instruments on an Index of Climate Policy Activity. The article presents an empirical application of this measurement approach. Focusing on national climate policy instruments in the energy production sector in Austria, Germany, and the United Kingdom, we investigate changes in the countries' policy portfolios from 1998 to 2010. The article demonstrates that our Index of Climate Policy Activity provides a reliable and valid measurement for national policy output that can be applied for comparative analyses of policy output. 相似文献
74.
Carlos de la Torre 《Postcolonial Studies》2017,20(2):187-198
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
75.
Daniel Loponte Mirian Carbonera María José Corriale Alejandro Acosta 《Environmental Archaeology》2017,22(3):247-267
We analyse the isotopic values (δ13C, δ15N) of the diet of pre-Columbian horticulturalist populations from tropical and subtropical areas of southeastern South America, belonging to the Guarani and Taquara archaeological units. The data indicate different trends in each one (T?=?4.21; P?=?0.0004), showing a mixed diet with maize consumption in the Guarani samples (δ13Cco?=??15.5?±?1.8‰; δ13Cap ?10.4?±?0.8‰) and a depleted one in the Taquara ones (δ13Cco ?18.2?±?1.7‰; δ13Cap ?11.9?±?0.9‰), with a significant internal dispersion in both populations. The first population has higher nitrogen values (δ15N 11.1?±?0.6‰) compared to the Taquara samples (δ15N 9.3?±?1‰), suggesting a more carnivorous diet. The recognition of these pre-Columbian mixed diets involves the identification of maize cultivation on the Atlantic side of the southernmost area of South America (Parana Delta, 34° SL). Through the analysis of δ18O we have identified two isotopic ecozones, the first along the Paraná River Valley, with an average value of δ18O ?3.7?±?0.5‰ (CV?=?13.5%; CI?=??3.83 / ?3.16), and the second one, located in the Planalto of southern Brazil (Araucaria Forest), with a mean value of δ18O ?1.5?±?0.3‰ (CV?=?16.5%; CI?=??1.69 / ?1.29). The isotopic data (δ13C, δ15N and δ18O) suggest human movements between these two ecozones. 相似文献
76.
77.
Wouter A. Marra Liesbeth van de Grint Koko Alberti Derek Karssenberg 《Journal of Geography in Higher Education》2017,41(2):213-229
Field courses are essential for subjects like Earth Sciences, Geography and Ecology. In these topics, GIS is used to manage and analyse spatial data, and offers quantitative methods that are beneficial for fieldwork. This paper presents changes made to a first-year Earth Sciences field course in the French Alps, where new GIS methods were introduced. Students use GIS in preparation to explore their research area using an elevation model and satellite images, formulate hypotheses and plan the fieldwork. During the fieldwork, a pilot group managed their field-observations using GIS and made digital maps. Students praise the use of quantitative digital maps in the preparation. Students made use of the available techniques during the fieldwork, although this could be further intensified. Some students were extra motivated due to the technical nature as well as the additional analytical possibilities. The use of GIS was experienced as a steep learning curve by students, and not all staff members are confident in supervising students using GIS, which calls for a sufficient preparation and training of both students and staff. The use of GIS adds abstract analyses and quantitative assessment, which is a complementary learning style to fieldwork that mostly focuses on practical skills. 相似文献
78.
Frederic Gaschet Mathieu Becue Vanessa Bouaroudj Marina Flamand André Meunie Guillaume Pouyanne 《European Planning Studies》2017,25(8):1292-1315
This article aims at assessing the role of related variety, that is, the relatedness of knowledge bases used by different sectors within a region, as a major driver of clusters’ development. Some recent theoretical papers underline the role of clusters as ‘knowledge platforms’ organizing the recombination of technologies in overlapping industries, following the seminal definition of clusters by Porter as ‘geographic concentrations of linked industries’. In order to investigate the role of related variety in cluster dynamics, we analyse the patterns of development of clusters specializing in photonics in Europe. Photonics constitutes a new and rapidly evolving set of technologies with a high expected degree of technological recombination. However, due to inadequate traditional sectoral classifications, we propose an original method to delineate the perimeter of photonics in patent databases. A two-step algorithm is then used to identify systematically photonic clusters in Western Europe at the local level. In the last part of the paper, a typology of technological trajectories of clusters over the last decades is developed and then correlated with a set of quantitative measures of technological relatedness. The results highly confirm the role of related variety as a major driver of success, particularly for the biggest European clusters. 相似文献
79.
Rita Ruiz Javier Rodríguez José M. Coronado 《International Journal of Heritage Studies》2017,23(4):362-374
There has been noticeable development in the protection of linear infrastructure by UNESCO, whether on its cultural, technological or historical merits. However, with the exception of other means of transport incorporated within the field of industrial archaeology or recognised by the CIIC under the category of cultural routes, little or no consideration has been given to roads built from the mid-eighteenth century to the early part of the twentieth century. In view of this situation, this paper has the following aims. Firstly, to define the concept of ‘modern road’ and provide a brief analysis of the historical development and current situation of the same. Secondly, to assess the main contributions made to date regarding the heritage dimension of modern roads. Thirdly, to reconstruct the process of defining linear cultural landscapes, historic transportation corridors, cultural routes and heritage canals, railways and roads, in accordance with the considerations raised by ICOMOS and UNESCO. Finally, to contribute to the debate on the definition, characterisation and assessment of modern roads as world heritage assets, both intrinsically and in relation to established heritage categories. 相似文献
80.