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1.
Research on small cities has begun to attract the attention of scholars who argue that contemporary urban scholarship, in its preoccupation with the largest and most advanced world-class cities, have largely ignored small to medium-sized cities. In China, although much attention has been paid to economically advanced urban centers, there actually has been a steady stream of work on small cities. This article profiles how a comparatively smaller city in western China attempts to market itself by selectively placing itself within various social–spatial and political–economic realities. Through Jinghong, we illustrate how local officials and planners attempt to center the city as a gateway to Southeast Asia. By activating, often discursively, multiscalar transborder strategies, local officials in Jinghong not only mobilize ethnic imaginaries, but they also adopt forms of entrepreneurial tactics to promote growth. Developmental strategies of Jinghong not only vacillate between (and draw on) both rural and urban resources; they are furthermore expected to alleviate rural poverty. Through highlighting the agency of small cities like Jinghong in China, this article speaks to the broader developmentalist critique of third- and fourth-world cities as an unfortunate footnote in global urban restructuring, often depicted as places of uniform marginalization and structural irrelevance. Indeed, by focusing on the geography of small cities and giving due attention to their size and proximity to rural spaces, case studies like Jinghong might yet point empathetically to different ways and imperatives of “being urban” where the weight that they carry can also be duly recognized.  相似文献   

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An outline is given of the career and scientific and teaching activity of the outstanding geomorphologist, professor of Moscow State University S.S. Voskresenskii, who created new scientific directions in the study of topography. He is rightfully given credit for geographical investigations of Siberia and the Far East in the latter half of the 20th century.  相似文献   

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China is the most populous country of the world.Besides her great numberof population she has also the most densely inhabited regions which are notcomparable with any other country of the world.The author collects the rec-  相似文献   

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The Distribution of Population in China,With Statistics and Maps.   总被引:1,自引:0,他引:1  
China is the most populous country of the world.Besides her great numberof population she has also the most densely inhabited regions which are notcomparable with any other country of the world.The author collects the rec-  相似文献   

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As they increase in popularity, social media are regarded as important sources of information on geographical phenomena. Studies have also shown that people rely on social media to communicate during disasters and emergency situation, and that the exchanged messages can be used to get an insight into the situation. Spatial data mining techniques are one way to extract relevant information from social media. In this article, our aim is to contribute to this field by investigating how graph clustering can be applied to support the detection of geo-located communities in Twitter in disaster situations. For this purpose, we have enhanced the fast-greedy optimization of modularity (FGM) clustering algorithm with semantic similarity so that it can deal with the complex social graphs extracted from Twitter. Then, we have coupled the enhanced FGM with the varied density-based spatial clustering of applications with noise spatial clustering algorithm to obtain spatial clusters at different temporal snapshots. The method was experimented with a case study on typhoon Haiyan in the Philippines, and Twitter’s different interaction modes were compared to create the graph of users and to detect communities. The experiments show that communities that are relevant to identify areas where disaster-related incidents were reported can be extracted, and that the enhanced algorithm outperforms the generic one in this task.  相似文献   

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The integration of multisource heterogeneous spatial data is one of the major challenges for many spatial data users. To facilitate multisource spatial data integration, many initiatives including federated databases, feature manipulation engines (FMEs), ontology-driven data integration and spatial mediators have been proposed. The major aim of these initiatives is to harmonize data sets and establish interoperability between different data sources.

On the contrary, spatial data integration and interoperability is not a pure technical exercise, and there are other nontechnical issues including institutional, policy, legal and social issues involved. Spatial Data Infrastructure (SDI) framework aims to better address the technical and nontechnical issues and facilitate data integration. The SDIs aim to provide a holistic platform for users to interact with spatial data through technical and nontechnical tools.

This article aims to discuss the complexity of the challenges associated with data integration and propose a tool that facilitates data harmonization through the assessment of multisource spatial data sets against many measures. The measures represent harmonization criteria and are defined based on the requirement of the respective jurisdiction. Information on technical and nontechnical characteristics of spatial data sets is extracted to form metadata and actual data. Then the tool evaluates the characteristics against measures and identifies the items of inconsistency. The tool also proposes available manipulation tools or guidelines to overcome inconsistencies among data sets. The tool can assist practitioners and organizations to avoid the time-consuming and costly process of validating data sets for effective data integration.  相似文献   

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Natural Resources Research - The U.S. Gulf of Mexico is a world-class hydrocarbon basin and industry has an impressive track record of advancing its capabilities in the region. From 1947 to 2017,...  相似文献   

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Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions, therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system. However, until now, the knowledge about the provenance and formation of these deserts in Xinjiang, Central Asia is diverse and inconsistent, a systematic review is necessary. Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts. Based on the geochemical, mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions, this paper reviews the research progress on the development of the sandy deserts in Xinjiang, Northwest China. Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial, alluvial and fluvial sediments and were eventually achieved because of the local sand supply. It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly, the East Asian winter monsoon and the topographical mountain-valley winds. However, the directions of transportation paths are different between the hydrological dynamics and the aeolian dynamics, which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes, respectively, and have determined anisotropies of the transport pathway of these sediments delivered by different agents. This results in a geological cycle of detrital sediment transportation in the two large basins and thus largely increases the degree of sediment mixing, alternation and recycle between younger and older sediment sources, as well as the complexity and diversity of sand provenances.  相似文献   

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Rivers and streams originating in the surrounding mountainous area are the major sources of salt in the Salinas Grandes basin (Córdoba, Argentina). These rivers infiltrate when they reach the sandflat or in the fringes of the mudflat, feeding springs which often form shallow lakes. Presently, the lakes are distant from the playa edge, thus allowing inflow waters to dissolve ancient (Pleistocene?) evaporite beds. In the sandflat environment, two dominant types of water have been recognized (SO 4 2? -Cl?-HCO 3 ? -Na+, and Cl?-SO 4 2? -HCO 3 2? -Na+), both considered as original members of the brine in the saline complex. Two main sources of solutes were distinguished, one related to the waters supplied by the southern sector and another to waters of the eastern sector. As a result of the chemical evolution in the playa environment, all brines belong to the neutral type (Cl?-SO 4 2? -Na+). Following Hardie and Eugster's (1970) model, waters from the southern sector should evolve towards an alkaline brine (Cl?-SO 4 2? -HCO 3 ? -Na+), whereas those from to the eastern sector should evolve towards a neutral one (Cl?-SO 4 2? -Na+). A computer simulation was carried out to model the chemical evolution of source waters. The results obtained by this methodology showed the same dichotomy (alkaline vs. neutral) established by Hardie and Eugster's (1970) model. The deficit in alkalinity could not be explained by any of the mechanisms published until now. Gypsum dissolution is the most likely mechanism which accounts for the chemical evolution of the waters investigated. When such a process is included in the computations, the Ca2+ supplied by gypsum beds generates an increase in the ion activity product (aCa+2·aCO 3 2? ) and produces a significant change in the 2Ca+2/(2CO 3 2? +HCO 3 ? ) ratio, switching from values less than 1 to values greater than 1. This process determines the precipitation of calcite, and leads to a decrease in alkalinity, which in turn would explain the existence of a neutral brine in the saline complex. An intermediate salinity brine was detected in the mudflat, which, according to the model (Hardie and Eugster, 1970), should evolve towards a SO 4 2? -free neutral brine (Cl?-Na+-Ca2+). The absence of this type of brine may be explained through mixing processes.  相似文献   

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Between 2000 and 2014, more than thirty geography departments adopted revised or new names, with some entirely dropping geography. Although renaming and rebranding efforts are not new to higher education, the rapid pace at which geography department names have changed raises questions about the discipline's identity and health. We examine the renaming trend within geography programs together with intended and unexpected factors as perceived by faculty. Specifically, we look at the renaming and rebranding trend within the context of four pillars offered by Pattison (1964 Pattison, W. D. 1964. The four traditions of geography. Journal of Geography 63 (5): 21116.[Taylor &; Francis Online], [Web of Science ®] [Google Scholar]) to define geography's principal academic domains—earth-science, man–land, area/regional studies, and spatial traditions.  相似文献   

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Although Jatropha curcas, an important tropical biofuel crop, is reputed for its drought resistance, its ability to perform under dry conditions has hardly been investigated. In a greenhouse experiment we investigated the plant–water relationships of Jatropha seedlings from different accessions under different levels of drought stress. There was little difference in plant–water relations between accessions. Drought significantly reduced leaf area, biomass and relative growth rate, but had no effect on specific leaf area, daily range in leaf water potential, leaf water content, transpiration efficiency or aboveground biomass water productivity, corrected for atmospheric conditions. Stem wood density was equally low (0.26 g cm?3) for all treatments. Stem water content was lowest for dry treatment seedlings. Based on these results, Jatropha could be characterized as a stem-succulent tree. In contrast to other stem-succulent deciduous trees, leaves were not shed immediately after the seedlings were confronted with drought. Instead, at the onset of drought, leaves with a higher adaxial stomatal density were formed, after which leaves were only gradually shed. The role of the succulent stem in the water economy of Jatropha was confined to balancing the small water losses of the leaves during drought.  相似文献   

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Based on biomass investigations,soil respiration and plant photosynthesis measurement of dominant trees in Hailuogou valley of Mt.Gongga,Southwest China,the carbon(C) storage,absorption and release for several typical woodlands in sub-alpine zones have been discussed.For Abies fahri forest of 3,000 m above sea level,the Cstorage amount is 177.4t/ha for above-ground biomass and 143.2 t/ha for soil below-ground biomass. The annual gross C fixed by vegetation photosynthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19 t/ha for surface soil and roots.The annual net C fixed of forest ecosystem is about 6.0-7.1 t/ha.At lower elevations,the amount of C released by woodlands is higher than that of woods at higher elevations.The C fixed capacity of renewed forest with middle-aged trees is higher than that of mature forest.Before becoming over-matured forest,woodland is an important sink of C whereas bareland in woods is the source of atmospheric C.  相似文献   

18.
The professional organizations to which geographers belong and by which they are represented have a civic duty and ethical responsibility to educate their members about mental health issues in their professions and, by default, their work environments. And yet national-level professional associations in North America are lagging behind universities in adopting initiatives, commissioning reports, and looking into best practices around the mental health of their members. A survey of the Web sites of sixty-six professional associations in the social sciences, geographical sciences, and humanities in the United States and Canada reveals an uneven presence of attention to mental health issues in terms of their members’ research on mental health issues, awareness of mental health as a professional development issue, and engagement in mental health advocacy and public outreach. In this article, we explore how geography’s professional organizations compare to others with respect to these issues and suggest ways in which they can develop their own mental health protocols to address the crisis of mental health in the academy. Key Words: Academic professional associations, American Association of Geographers, Canadian Association of Geographers, mental health, mental health practices and policies.  相似文献   

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《The Journal of geography》2012,111(3):87-101
Abstract

Between 1990 and 2000 the U.S. Hispanic population increased by 14 million, which is the largest decadal population rise in United States history. This increase was not spread evenly throughout the United States, nor was it isolated to locations that already had large Hispanic populations. On the contrary, areas that previously had a relatively small Hispanic population experienced large percentage increases. In this article the regional variability in Hispanic population growth is explored, along with an emphasis on the economic pull factors driving those demographic changes. This analysis illustrates how restructuring in the meatpacking industry, and the associated economic impacts, have created a dependence on a low wage, illegal labor force that has shaped the recent demographic trend in the South and Midwest.  相似文献   

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