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SUZANNE ZELLER 《Geographical review》2006,96(3):382-398
ABSTRACT. Alexander von Humboldt's influence in British North America during the nineteenth century was filtered mainly through British imperial applications of “Humboldtian” sciences, including geomagnetism and biogeography. The best‐known examples include Edward Sabine and John Henry Lefroy, Royal Artillery officers who, during the 1830s and 1840s, transformed British North American outposts and territories, including Rupert's Land, into Humboldtian sites and regions in Great Britain's imperial “magnetic crusade.” Important groundwork had already been laid by John Richardson, who applied data accrued during John Franklin's overland Arctic expeditions during the 1820s to systematize Humboldtian inquiries into the habitability of Canada's Great Northwest. Despite both the relative decline of Humboldtian sciences by midcentury and Humboldt's own reservations about the political ramifications of his science, his “cosmic” outlook circulated in Canada to refine territorial expansionists' scientistic arguments justifying annexation of Rupert's Land after the monopoly of the Hudson's Bay Company expired in 1869. 相似文献
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阐述了GIS网络分析中不确定性选址问题的基本模型及特性。从问题的定义可知其为NP完备类问题。推导了最优解在紧条件的下界算法,并结合广义Powell算法及遗传算法,提出了不确定性选址问题的混合遗传算法,实验证明,在最优解的品质和收敛速度上都达到了比较好的效果。同时,实验的结果从另一个角度证明,如果兼顾收敛速度和解的品质这两个指标,单纯的遗传算法未必比其他搜索算法更优越,采用一些局部搜索性能较好的算法结合遗传算法,可以从两方面改善求解效果。 相似文献
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KENNETH R. OLWIG 《Geographical review》2007,97(2):175-190
ABSTRACT. I use my personal experience as an islander doing fieldwork among islanders in the West Indies to explore the meaning of “insularity.” I then expand on that personal experience by drawing on literary sources, particularly Homer's the Odyssey and Herman Melville's Moby Dick, both of which express an island worldview. The island worldview is contrasted and compared with the continental worldview on the basis of differing modes of navigation and cartography and differing modes of orientation as defined by cognitive psychologists. 相似文献
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This paper describes the application of the Powell algorithm to the optimization of a flow injectionsystem configuration.The performance of this algorithm has been compared with the modified simplexmethod.The system studied is the determination of ammonia,based on the indophenol blue reaction.Alinear combination of sensitivity and sample throughput is used as the objective function because of itssimultaneous optimization capability.Results obtained show that the proposed method may reach theoptimal conditions with a lower number of experimental evaluations. 相似文献
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Activity–composition relations for the calculation of partial melting equilibria in metabasic rocks 
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下载免费PDF全文 E. C. R. Green R. W. White J. F. A. Diener R. Powell T. J. B. Holland R. M. Palin 《Journal of Metamorphic Geology》2016,34(9):845-869
A set of thermodynamic models is presented that, for the first time, allows partial melting equilibria to be calculated for metabasic rocks. The models consist of new activity–composition relations combined with end‐member thermodynamic properties from the Holland & Powell dataset, version 6. They allow for forward modelling in the system NaO–CaO–KO–FeO–MgO–AlO–SiO–HO–TiO–FeO. In particular, new activity–composition relations are presented for silicate melt of broadly trondhjemitic–tonalitic composition, and for augitic clinopyroxene with Si–Al mixing on the tetrahedral sites, while existing activity–composition relations for hornblende are extended to include KO and TiO. Calibration of the activity–composition relations was carried out with the aim of reproducing major experimental phase‐in/phase‐out boundaries that define the amphibolite–granulite transition, across a range of bulk compositions, at ≤13 kbar. 相似文献
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Robert W. Lake 《Urban geography》2017,38(4):507-511
Emerging commonalities between philosophical pragmatism and contemporary political thought suggest that those who find resonance in recent political theory will find in Deweyan pragmatism a fruitful source of insight and inspiration. Pragmatism’s commitments share deep affinities with parallel impulses in feminist and post-positivist thought animating engaged, activist scholarship inside and outside of geography. An ethic of radical equality applies equally, for Dewey, as a theory of democratic practice and a mode of being in the world. 相似文献
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《The Journal of geography》2012,111(6):254-260
Abstract The rise of service-learning in higher education has been critiqued as little more than community service that encourages students to “do good,” but fails to generate original scholarship or social change. In this article, we argue that service-learning gives geographers the opportunity to challenge these critiques, by demonstrating the practical and political implications of collaborative research methodologies, while conveying powerful conceptual understandings of inequality. We begin by interrogating the philosophical overlap between experiential and service-based learning in the educational philosophy of John Dewey. Using this foundational approach, several theoretical and methodological debates in geography are examined, celebrating and drawing lessons from classic and current service-learning programs. We conclude with a discussion and reflection on experiences with implementing similar pedagogical projects. 相似文献