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321.
ABSTRACT. The area-studies model of global scholarship, based on dividing the world into a set number of large, quasi-continental regions, is under assault from a variety of intellectual and institutional forces. New, less rigid models of global scholarship are increasingly being called for by both scholars and funding agencies. One useful alternative, currently being explored at Duke University, reframes area studies around ocean and sea basins. Putting maritime interactions at the center of vision brings to light a set of historical regions that have largely remained invisible on the conventional map of the world. 相似文献
322.
Abstract Inertial waves are excited in a fluid contained in a slightly tilted rotating cylindrical cavity while the fluid is spinning up from rest. The surface of the fluid is free. Since the perturbation frequency is equal to the rotation speed resonance occurs at a critical height to radius aspect ratio of the fluid. Detailed study of a particular inertial wave shows that in solid body rotation this “eigenratio” agrees with predictions from linear inviscid theory to within 0.5%. Measured time dependence of the eigenratio during spin-up from rest is a function of the tilt amplitude and agrees favorably with predictions from a numerical study. Mean flow associated with the inertial wave becomes unstable during spin-up and in the steady state. A boundary for the unstable region is found experimentally. 相似文献
323.
采用新编《系列世界地图》绘制出一套四种全球板块分布图,具体分为,“东半球版”、“西半球版”、“北半球版”和“南半球版”.其中,“东半球版”和“西半球版”为“经线全球板块分布图”,适用于反映东、西半球的板块构造分布;“南半球版”和“北半球版”为“纬线全球板块分布图”,适用于反映南、北半球的板块构造分布.基于《系列世界地图》的全球板块分布图以东、西、南、北四种视角,从经度、纬度两种方向,将全球板块构造以多元化的形式地表达出来,为深入研究板块相互作用和运动机制,提供一种新的图形工具. 相似文献
324.
325.
Fenda A. Akiwumi 《Singapore journal of tropical geography》2011,32(1):53-70
This paper draws from world‐systems and sustainable livelihoods approaches to analyze the connections between multinational exports of rutile (titanium oxide), diminished ecological resources and resource‐based livelihoods, and gendered household dynamics in a peripheralized mining region in Sierra Leone. The discussion focuses on how the extraction of mineral resources instigated by exogenous capital investors forces links to household transformation, particularly the vulnerability context of women. Using archival records and field survey data, the case study of rutile mining in southwestern Sierra Leone connects the low‐waged mining labour of traditional resource‐based subsistence communities and deepening marginalization of and financial pressures on women in mining households to global mineral markets. The study focuses on women's coping mechanisms that are embedded within traditional social networks in relation to an external intervention, a low‐tech mechanical cassava grater, intended to strengthen their livelihoods. It finds that the potential for this transformation is impeded by sociocultural, environmental and financial limitations. 相似文献
326.
茶园生态系统氟的生物地球化学循环 总被引:1,自引:0,他引:1
根据近年作者及相关研究成果,提出一般茶园(非F污染区,非高F地质背景区)生态系统F的生物地球化学循环模型,估算茶园生态系统各子系统F的库容和库之间的F流量,分析茶园生态系统F的生物地球化学特征.结果表明:1)茶园生态系统F的惰性库:调节库:活动库为239:4:1,活动库占总库容的比例高达0.41%,其比例是非常高的;2... 相似文献
327.
Pontus Hennerdal 《制图学和地理信息科学》2013,40(1):76-85
ABSTRACTMany map readers, including both children and adults, find it difficult to determine where they would be located along the edge of a world map after crossing that edge. Different types of markers have long been drawn close to the map’s edge – for example, in an atlas – to help map readers identify the map upon which they will find themselves if that edge is passed. In this study, a method similar to that used to show the continuity between maps in an atlas has been tested to determine whether continuity markers can also be used to help map readers find a world map’s actual peripheral continuity. The study involved children between the ages of 10 and 13 years and showed that continuity markers do help children determine the map’s actual peripheral continuity, in combination with a lesson that describes how to find the actual peripheral continuity of a world map. This article, therefore, concludes that continuity markers for world maps can be a useful part of map design that clarifies how the edges of a world map fit together for children who have learned to use this tool. 相似文献
328.
Elien Van De Vijver Ben Derudder David Bassens Frank Witlox 《The Professional geographer》2013,65(1):82-90
This empirical article combines insights from previous research on the level of knowledge-intensive service in metropolitan areas with the aim to develop an understanding of the spatial structure of the global service economy. We use a stepwise regression model with the Globalization and World Cities research network's measure of globalized service provisioning as the dependent variable and a range of variables focusing on population, infrastructure, urban primacy, and national regulation as independent variables. The discussion of the results focuses on model parameters as well as the meaning of outliers and is used to explore some avenues for future research. 相似文献
329.
Megan Dixon 《Urban geography》2013,34(3):353-375
Abstract The courtyard is a space that existed before, during, and now after the Soviet period in Russian urban history. Noting the change in the courtyard's formerly hegemonic position on daily trajectories illustrates both Harvey's and Lefebvre's suggestions for uncovering the way that spaces articulate social values. A particularly revealing case study occurs in the struggle over including courtyards in a Chinese developer's project for a new multi-use district outside St. Petersburg. A brief history of the courtyard in Soviet planning allows subsequent analysis of the ways in which the city administration, the Chinese design team, and Russian planners deployed the courtyard as a spatial code for social meaning in design discussions. Examining the change in function and conceptualization of the courtyard shows how different groups in post-Soviet Russia seek to retain or redeploy concepts of the “collective” as they attempt to remake St. Petersburg as a successful “world” city. 相似文献
330.
Distribution of Aluminum and Fluoride in Tea Plant and Soil of Tea Garden in Central and Southwest China 总被引:4,自引:0,他引:4
The distribution of Al and F contents and the relationship between Al and F in tea plants and soils of 12 tea gardens in Central and Southwest China were investigated from October 31 to November 14, 2006. The results show that there were differences in pH, CEC, the contents of organic matter (OM), Al and F in the different soils of the tea gardens. The Al content ranged from 1196 to 7976mg/kg for old leaf, 370 to 2681mg/kg for young leaf and 285 to 525mg/kg for stem, whereas the content of F ranged from 221 to 1504mg/kg for old leaf, 49 to 602mg/kg for young leaf and 13.5 to 77.5mg/kg for stem. The concentrations of labile Al varied obviously in the different soils, but the distribution law of labile Al content for the same garden was Alexchangeable≈AlFe-Mn oxide>Alorganic>Alwater-soluble. The contents of different labile F fractions varied slightly in the different soils and the different soil layers, though the exchangeable F content was lowest among the labile F in the soils. The concentrations of Al and F in tea plants increased with increasing amount of water-soluble Al or F, especially the amount of water-soluble fractions in the soil layer of 0-20cm.The correlation between Al content and F content in the tea leaf was more significant than that in the tea stem. Furthermore, the correlation between Al content and F content in whole tea plant was strongly significant (r=0.8763, p<0.01, n=36). There were evident tendency that Al concentration increased with the increase of F concentration in different soil layers. The correlation of water-soluble Al with water-soluble F in all soils was also strongly significant (r=0.7029, p<0.01, n=34). The results may provide a proof that Al and F are jointly taken up by tea plants to some extent in natural tea gardens. 相似文献