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排序方式: 共有192条查询结果,搜索用时 46 毫秒
91.
Ted Goebel Heather L. Smith Lyndsay DiPietro Michael R. Waters Bryan Hockett Kelly E. Graf Robert Gal Sergei B. Slobodin Robert J. Speakman Steven G. Driese David Rhode 《Journal of archaeological science》2013
The dispersal of Homo sapiens across the New World is one of the greatest chapters in the history of our species; however, major questions about this late Pleistocene diaspora remain unanswered. Two contentious issues are the timing of colonization of the Bering Land Bridge and origin of Clovis, which at 13,000 calendar years ago is the earliest unequivocal complex of archaeological sites in temperate North America, known by its specialized fluted spear points. One hypothesis is that fluting technology emerged in Beringia and from there was carried southbound, with fluted points becoming the diagnostic “calling card” of early Paleoindians spreading across the Western Hemisphere. Fluted points have long been known from Alaska, yet until now they have never been found in a datable geologic context, making their relationship to Clovis a mystery. Here we show that a new archaeological site at Serpentine Hot Springs, Bering Land Bridge National Preserve, Alaska, contains fluted points in a stratified geologic deposit dating to no earlier than 12,400 calendar years ago. Our results suggest that Alaska's fluted-point complex is too young to be ancestral to Clovis, and that it instead represents either a south-to-north dispersal of early Americans or transmission of fluting technology from temperate North America. These results suggest that the peopling of the Americas and development of Paleoindian technology were much more complex than traditional models predict. 相似文献
92.
Philippe Le Billon Manoj Suji Jeevan Baniya Bina Limbu Dinesh Paudel Katharine Rankin Nabin Rawal Sara Shneiderman 《Development and change》2020,51(4):939-969
The political economy literature on post-disaster reconstruction tends to contrast ‘disaster capitalism’ narratives denouncing the predatory character of neoliberal rebuilding, and ‘building back better’ policies supporting market-driven reconstruction. This article seeks to provide a more nuanced account, developing the concept of ‘disaster financialization’ through a case study of household-level changes experienced through processes of post-earthquake reconstruction in Nepal. The concept of disaster financialization describes not only the integration of disaster-affected households into the cash-based logic of reconstruction instituted by donors and government authorities, but also the financialization of their lives, social relations and subjectivities. It is a transitive process involving a shift into financialized mechanisms of disaster prevention, adaptation and recovery. Analysing contrasting experiences across three earthquake-affected districts in Nepal, this study proposes disaster financialization as an integrative term through which to understand the simultaneous acceleration of monetization, the leveraging of cash incentives by donors and government to ‘build back better’, and the flurry of financial transactions associated with reconstruction processes. While some aspects of disaster financialization have had negative social impacts, such as debt-related anxieties and a breakdown of voluntary labour exchanges hurting the most vulnerable, the process has taken on variegated forms, with equally variegated effects, reflecting household characteristics and interactions with financial institutions. 相似文献
93.
Peter J. May Bryan D. Jones Betsi E. Beem Emily A. Neff-Sharum Melissa K. Poague 《政策研究杂志》2005,33(1):37-63
This research extends theorizing about the implications of political environments to the content of policy areas. We consider the case of Arctic policy in Canada and the United States as an example of what we label as component-driven policymaking. We show how the lack of a clear constituency and the lack of a stable policy subsystem for the Arctic create a policy environment for which the politics of particular issues dominate Arctic policymaking. The result is a policy space labeled Arctic policy that lacks policy coherence. We suggest that similar features of component-based policymaking help explain limited policy coherence for a variety of policy areas such as policies for children, families, rural areas, urban areas, and women in the United States. 相似文献
94.
In this article, we trace the evolution of punctuated equilibrium theories of the policy process to the development of a full theory of government information processing. Noting that punctuated equilibrium is one realization of a larger theory of government information processing, we outline a research agenda for the study of agenda setting, policy dynamics, and information flows in the policy process. In doing so, we relate the study of government information processing to such important features of American government as inter-institutional dynamics and delegation in the policy process. 相似文献
95.
伞又称盖,或称伞盖,在佛教中常用于佛、菩萨等头顶,以示尊崇.结合敦煌文书和出土实物可知,以丝、麻等面料缝制的伞盖是唐代敦煌寺院伞盖中的大宗,多为方形或圆形,大小不一.根据伞盖的使用方式可将其分为悬挂型和支撑型两种类型.伞面为单层或夹层,伞缘的下端有时会垂有织物制作的"裙".除此以外,"者舌"、"柱子"和"带"也是敦煌伞盖常有的构件. 相似文献
96.
97.
Brett A. Bryan 《Geographical Research》2002,40(2):196-209
This paper re‐examines the chronology of reserve selection in South Australia in the context of changing social, political and economic attitudes. The effect of these changing attitudes on reserve selection in South Australia is assessed in the light of the principles of a comprehensive, adequate and representative (CAR) National Reserve System. The outcome of reserve selection in South Australia is the establishment of a vast network of reserves in the arid regions and many fragmented and small reserves in the agricultural regions. It is likely that the remnant ecological system in the agricultural regions is not representative of the regional environmental diversity and that land clearance has precluded the establishment of a CAR reserve system in South Australia. The rate of reserve selection for nature conservation has decreased over the past decade as the opportunities for reserve acquisition decrease. It is concluded that large‐scale and strategic revegetation will be required to facilitate a CAR reserve system in South Australia. 相似文献
98.
Interfacility Interaction in Models of Hub and Spoke Networks 总被引:3,自引:0,他引:3
Providers of transportation services may reduce their average unit costs by bundling flows and channeling them between hubs (also known as concentrators or routers). The resulting facility locations are interdependent because of the flows between them. This paper analyzes mathematical models of hub systems in an effort to enhance understanding of the optimal location of interactive facilities. The paper examines the behavior of solutions to several alternative models that require the location of a hub at either of two similar locations. A model employing a concave cost function favors the assembly of flows, penalizes fractional facility locations, and produces local minima that have integer facilities. 相似文献
99.
Carlo Lugliè François-Xavier Le Bourdonnec Gérard Poupeau Enrico Atzeni Stéphan Dubernet Philippe Moretto Laurent Serani 《Journal of archaeological science》2007
All the obsidians from the undisturbed Early Neolithic (Cardial ware phase I) layer of the Su Carroppu rock-shelter (Sardinia island) were studied. Their elemental composition and that of obsidians from the Monte Arci (Sardinia) volcanic complex was determined by ion beam analysis (PIXE). A comparison between the composition of Su Carroppu artefacts, analysed non-destructively, and that of Western Mediterranean analysed in the same conditions shows that the archaeological material belongs to the SA, SB2 and SC Monte Arci-types, to the exclusion of the SB1 type. The typological/technological study of this industry allowed us to reconstruct two chaînes opératoires, for the production of blades (using predominantly SC obsidians) and of flakes (based exclusively on SA and SB2 obsidians), respectively, but on the whole, assemblage blade/bladelet production was performed somewhat preferably with SA and SB2 types. Thus, in the earliest EN culture known on the island, ancient man had, for the making of its obsidian toolkit, a highly adaptive behaviour applied to the reduction of different useful obsidian sources. 相似文献
100.