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171.
172.
Geographers have assessed the success and failure of the U.S. Civil Rights Movement in terms of the African American struggle for justice, social identity, and economic survival. Conspicuously absent from the geographic literature are pedagogically oriented studies of the historical geography of the Civil Rights era. The Movement's popular image has congealed into a celebratory collection of names and dates, the sum of which is a vague, nearly mythic retelling that students might recognize but not necessarily care about. As a result, the Movement is at once contemptuously familiar yet bewilderingly strange for our students. This article offers a sympathetic critique of conventional Movement narratives, introducing the notion of empathetic pedagogy and presenting a case study of the Montgomery bus boycott. Our pedagogical approach stresses the role of empathy, both as a factor in shaping the actual sociospatial development of the Movement, as well as a strategy for encouraging students to appreciate the everyday courage and sacrifice that animated so many of its participants. Our study brings together two burgeoning literatures that have the potential to cultivate empathy among students: the critical reevaluation of mobility and explorations of subjectivity from a psychoanalytic perspective. Here mobility is understood in both its literal and figurative sense: in the case of the bus boycott, the intricate network established to literally move African Americans around the city, as well as the figurative movement of sympathy and solidarity that “moved” people to support their efforts and now informs popular, selective understandings of the protest.  相似文献   
173.
Residential mobility can be conceptualized as an outcome of a choice process exercised under complex institutional and personal constraints. China's rather unique pattern of housing market segmentation under market transition impinges directly on residential location and relocation. Drawing upon data from a sample survey, this paper analyzes the pattern of residential moves resulting from commodity housing construction in a major Chinese city, Guangzhou. Most moves are of short distance, although the general direction is towards the urban periphery. Danweis and the municipal housing bureau, rather than the market per se, are the primary driving forces behind suburbanization in China today.  相似文献   
174.
Pervasive presence of location-sharing services made it possible for researchers to gain an unprecedented access to the direct records of human activity in space and time. This article analyses geo-located Twitter messages in order to uncover global patterns of human mobility. Based on a dataset of almost a billion tweets recorded in 2012, we estimate the volume of international travelers by country of residence. Mobility profiles of different nations were examined based on such characteristics as mobility rate, radius of gyration, diversity of destinations, and inflow–outflow balance. Temporal patterns disclose the universally valid seasons of increased international mobility and the particular character of international travels of different nations. Our analysis of the community structure of the Twitter mobility network reveals spatially cohesive regions that follow the regional division of the world. We validate our result using global tourism statistics and mobility models provided by other authors and argue that Twitter is exceptionally useful for understanding and quantifying global mobility patterns.  相似文献   
175.
唐雪琼  杨茜好  钱俊希 《地理研究》2016,35(8):1535-1546
边界是不同的社会与政治实体接触和交流的场所,跨边界的日常生活流动是历久和普遍的社会事实。边民与边境管理者丰富的跨界流动性实践,包括了自下而上到自上而下的双向互动,促进了边界意义的生产与再生产。透过流动性的研究视角,基于Newman对边境的地理学问题研究论调,从边境管理者和边民两个方面的日常空间实践进行了展现,选取云南省河口县中越边境地区的典型边寨为案例地,通过质性研究方法分析跨界流动的空间实践及其意义,进一步为解读边界的空间意义提供中国案例,以期更全面地看待边界问题。研究发现:边境草根群体自下而上的跨界流动,促进边界成为衡量经济、社会关系、文化意义以及政治权力形成和变迁过程的一个重要变量和维度。跨界流动实用主义色彩之上,也作用于边境社会关系网络的建构,对边民民族文化认同、国家认同等的建构产生积极作用。权力机关在边境生存法则基础上的流动性实践深化了国家意志,边界即成为权力“物化”的工具,流动性形成治理的手段和方法之一,边境地区同时被不断地规划和塑造。  相似文献   
176.
中国页岩气资源丰富, 但勘探水平相对较低。在钻井、测井资料匮乏的条件下, 高精度地震流体检测方法的研究至关重要。从地震弹性波方程入手导出了流体活动因子表达式, 该因子与储集层密度、黏度和渗透性成正比。将流体活动因子分析与高精度时频分析结合, 形成用于页岩气“甜点”预测的实用方法, 即首先基于高精度时频分析, 分析流体的时频特性, 计算出流体活动因子, 进而与测井资料结合量化页岩气“甜点”区流体活动因子的范围, 从而预测页岩气“甜点”分布区。该方法在四川盆地的应用表明, 其预测结果与钻井、测试结果吻合, 取得了良好的勘探效果, 对页岩气勘探具有重要的指导作用。  相似文献   
177.
Although studies of sediment transport in steep and coarse-grained channels have been more numerous in recent years, the dynamics of sediment transport in step–pool river systems remain poorly understood. This paper investigates displacements of individual clasts through Spruce Creek (Québec, Canada), a classic step–pool channel, and the effects of the channel morphology on the path length of the clasts. Passive integrated transponder tags (PIT) were used to track the displacement of 196 individual particles over a range of discharges including the bankfull stage. Clasts were tracked after five sequences of flood events. The results showed that the distance distributions match a two-parameter Gamma model. Equal mobility transport occurs for the particle size investigated during each sequence of flood events. Mean travel distance of the clasts can be estimated from excess stream power, and the mobility of the clasts is more than an order of magnitude less than the model reported in riffle–pool channels. The dominant morphological length scale of the bed also controls the path length of the clasts. These results confirm some preliminary observations on sediment transport in step–pool channels.  相似文献   
178.
The numerical simulation of liquefaction phenomena in fluid-saturated porous materials within a continuum-mechanical framework is the aim of this contribution. This is achieved by exploiting the Theory of Porous Media (TPM) together with thermodynamically consistent elasto-viscoplastic constitutive laws. Additionally, the Finite Element Method (FEM) besides monolithic time-stepping schemes is used for the numerical treatment of the arising coupled multi-field problem. Within an isothermal and geometrically linear framework, the focus is on fully saturated biphasic materials with incompressible and immiscible phases. Thus, one is concerned with the class of volumetrically coupled problems involving a potentially strong coupling of the solid and fluid momentum balance equations and the algebraic incompressibility constraint. Applying the suggested material model, two important liquefaction-related incidents in porous media dynamics, namely the flow liquefaction and the cyclic mobility, are addressed, and a seismic soil–structure interaction problem to reveal the aforementioned two behaviors in saturated soils is introduced.  相似文献   
179.
The inclusion of new groups of workers has been an important component of union renewal efforts. Several unions in Canada have begun to dedicate significant resources to better organize and represent Aboriginal workers. Drawing on interviews with union activists, organizers and representatives from two national public sector unions in Canada, we present an overview of union strategies to engage with Aboriginal peoples. Results suggest that understanding the distinct territorial context of Aboriginal peoples’ relationships to work and unions has been necessary to the success of these union strategies. This approach begins by drawing connections between Aboriginal peoples’ present-day relationships to work and their prior occupancy of, and dispossession from, lands and resources. Because of the geographical specificity of how the colonial experience affected Aboriginal peoples’ relationships to work and unions, unions have had to adopt non-normative approaches to their engagements with Aboriginal peoples. In workplaces where settlers were dominant, addressing racism in the workplace and gaining support for initiatives to hire and train Aboriginal workers were important. Alternatively, in Aboriginal workplaces, organizing was a priority. Here questions of union legitimacy have taken precedence and the focus of unions has been on partnership building. Most importantly, however, engagement with Aboriginal peoples has brought attention to the colonial practices within unions and helped to foster growing Aboriginal voice within the labour movement.  相似文献   
180.
砷的地球化学特征与研究方向   总被引:2,自引:1,他引:1  
伯英  罗立强 《岩矿测试》2009,28(6):569-575
砷的毒性在古代就因砒霜而广为人知,国际癌症研究会将砷列为第一类致癌物。目前,世界上有数以百万计的人受到砷中毒的威胁,砷污染事件在世界范围都有报道。环境中的砷的来源很复杂,有自然因素引起的砷污染(主要是地质成因砷污染),也有人为活动带来的砷污染,还有二者共同作用形成的砷污染。此外,砷还可以通过各种自然的地球化学过程和生物过程进行迁移转化,直接或间接对人和动物等产生危害。文章从砷的来源与分布、砷的毒性和危害、砷的迁移转化、生物在砷循环中作用的新认识等方面进行论述,并针对目前国内外砷污染研究现状,提出在已有研究基础上,建议在河套地区进一步开展砷元素地球化学及人体健康关系研究。  相似文献   
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