排序方式: 共有51条查询结果,搜索用时 328 毫秒
1.
2.
Petrological and geochemical evidence is presented on the occurrence of aegirine in the Palaeoproterozoic Hotazel iron‐formation, which hosts the giant manganese deposits of the Kalahari manganese field, South Africa. The mineral has an essentially pure Na end‐member composition and occurs sporadically in iron‐formation immediately bordering the manganese ore beds. The development of aegirine appears to have taken place due to the action of late‐infiltrating, saline hydrothermal fluids at the expense of a pre‐existing, binary quartz–hematite assemblage. It is proposed that such a process would have overprinted (and therefore post‐dated) a spatially more extensive, low‐temperature alteration event which brought about thorough carbonate leaching, oxidation and residual enrichment of metals in the Hotazel iron–manganese rocks. 相似文献
3.
A. CRISTINA DE LA VEGA‐LEINERT SUSANNE STOLL‐KLEEMANN TIM O'RIORDAN 《Geographical Research》2009,47(4):351-361
This paper makes the case for advancing sustainability science partnerships (SSPs) both within universities and through innovative means of integrating universities with external public‐private and civil sectors. It links the basic principles of sustainable development with an emerging science of cooperative learning that connects researchers to a wide range of partners. SSPs are specifically designed to be transformational through becoming active agents for societal change. Universities play a special role here because they can act both as communication networks and as laboratories for developing the capability to design and manage SSPs in the creative transition to sustainability. It is gratifying to note that these ideas are beginning to emerge in a number of universities, with European examples being highlighted in this paper. Further steps towards introducing full‐blooded SSPs across the university spectrum are suggested. 相似文献
4.
5.
Although the elderly population is increasing rapidly in all parts of Canada, the pattern of change is far from uniform. A number of properties of the aging process are strongly differentiated at the county and township levels, variations which have considerable significance for the design and implementation of social service and health care systems. Using data from the 1976, 1981, and 1986 Censuses for Ontario, components of change in the elderly population are obtained by cohort survival methods. The significance of rapid metropolitan growth of the elderly compared with the slow growth of the rural elderly is highlighted, while intra-county distributional shifts in the elderly population raise important questions for the next decade.
Quoique l'âge de la population augmente rapidement à travers le Canada, ce changement nes'opèrepas de façon uniforme. Certaines caractéristiques du processus de vieillissement sont vraiment differentes à l'échelle des comtés et des municipalités. Ces différences sont d'une grande importance lors de la création etde l'implantation des services-santé et des services sociaux. À l'aide des statistiques de recensement pour les années 1976, 1981, et 1986 pour l'Ontario, les facteurs de changement des populations de personnes âgées sont obtenus au moyen des paramètres de 'survie des groupes.' La signification du taux d'accroissement rapide des personnes â gés en milieu urbain comparé au taux d'accroissement plus lent de ces mêmes personnes en milieu rural est mise en évidence. Les variations de la distribution de cette population d'un comtéà I'autre soulèvent d'importantes interrogations pour la prochaine décade . 相似文献
Quoique l'âge de la population augmente rapidement à travers le Canada, ce changement nes'opèrepas de façon uniforme. Certaines caractéristiques du processus de vieillissement sont vraiment differentes à l'échelle des comtés et des municipalités. Ces différences sont d'une grande importance lors de la création etde l'implantation des services-santé et des services sociaux. À l'aide des statistiques de recensement pour les années 1976, 1981, et 1986 pour l'Ontario, les facteurs de changement des populations de personnes âgées sont obtenus au moyen des paramètres de 'survie des groupes.' La signification du taux d'accroissement rapide des personnes â gés en milieu urbain comparé au taux d'accroissement plus lent de ces mêmes personnes en milieu rural est mise en évidence. Les variations de la distribution de cette population d'un comtéà I'autre soulèvent d'importantes interrogations pour la prochaine décade . 相似文献
6.
7.
8.
TIM SUMMERS 《International affairs》2015,91(5):1151-1160
China's social and economic transformations, and their growing global impact, have prompted a plethora of books. This review article examines five recent books in Polity's China today series as a basis for discussion about society and politics in China. The series is structured around applying different themes or concepts to China, and these five look at consumption, social welfare, class, ethnicity, and the nature, role and performance of the Communist Party and state. The books provide well‐researched and balanced accounts of developments in China, especially since the era of ‘reform and opening up’ began in 1978. The article argues that important themes of the books—the growing discourse of consumption, the depoliticization of class as socio‐economic strata, the Party‐state as a pragmatic provider of citizen services, and the role of the private sector in the provision of social welfare—are all features of the current phase of a globalized capitalist modernity, and concludes that while the country wants to be seen as different, the accounts of politics and society in this series suggests that China today offers more of an alternative within that modernity than an alternative to it. 相似文献
9.
10.
TIM REIFFENSTEIN 《The Canadian geographer》2006,50(3):298-318
Recent research in economic geography has emphasized tacit knowledge as the basis of industrial learning. In contrast, codification and the practices of industrial writing have received little attention for the roles they play in mobilizing knowledge across space. This paper offers insight into the geographies of codification through an examination of technology transfer in the electronic musical instrument industry between 1965 and 1995. The research draws on a variety of primary and secondary data that include interviews with inventors, biographical accounts and patent analysis. These sources offer perspective on the career trajectories of three U.S. inventors who transferred knowledge from various contexts in California's high-tech industry to the Japanese firm, Yamaha. Conceptually, the paper draws on the actor–network theory and Latour's idea of translation to highlight the detours inventors must take to register novelty. The analysis reveals the problematic nature of codified knowledge and its transfer; in this case codified knowledge was mobile internationally but not locally, at least until it reached Japan. The paper argues for the need to understand how texts such as patents are produced—the context of their authorship, the geographies of their circulation and their efficacy for shaping further innovative practice. 相似文献