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Minze Stuiver Stephen W. Robinson H. GöteÖstlund H. Gorman Dorsey 《Earth and Planetary Science Letters》1974,23(1):65-68
Cross-checks between the Washington and Miami Geosecs radiocarbon laboratories verify that results on identical samples measured at the two laboratories agree with the stated accuracy of each laboratory which is±4‰inΔ14C. 相似文献
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土壤中稀土元素地球化学研究进展 总被引:12,自引:1,他引:12
综述了土壤中稀土元素含量、稀土赋存形态、稀土生物有效性、稀土在土壤环境中的分布规律、迁移方式及其影响因子。讨论了稀土微肥应用中应注意的问题以及由此带来的环境效应,并探讨了建立具有普遍适用性的稀土生物有效性方法学的途径等。 相似文献
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Florian W. Fichtner Abdoulaye A. Diakité Sisi Zlatanova Robert Voûte 《Transactions in GIS》2018,22(1):233-248
3D indoor navigation in multi‐story buildings and under changing environments is still difficult to perform. 3D models of buildings are commonly not available or outdated. 3D point clouds turned out to be a very practical way to capture 3D interior spaces and provide a notion of an empty space. Therefore, pathfinding in point clouds is rapidly emerging. However, processing of raw point clouds can be very expensive, as these are semantically poor and unstructured data. In this article we present an innovative octree‐based approach for processing of 3D indoor point clouds for the purpose of multi‐story pathfinding. We semantically identify the construction elements, which are of importance for the indoor navigation of humans (i.e., floors, walls, stairs, and obstacles), and use these to delineate the available navigable space. To illustrate the usability of this approach, we applied it to real‐world data sets and computed paths considering user constraints. The structuring of the point cloud into an octree approximation improves the point cloud processing and provides a structure for the empty space of the point cloud. It is also helpful to compute paths sufficiently accurate in their consideration of the spatial complexity. The entire process is automatic and able to deal with a large number of multi‐story indoor environments. 相似文献
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Amber-signs in the Latvian nation-state’s semiotics, constructed during the interwar period, are only bits and pieces of a complex system such as the State. However, the resonance that amber semiotics effectuated, despite its actual rarity, was and still is remarkably influential. Amber was extensively deployed as a signifier to the territory and its people, places and things; it signified patria, belonging and the homeland. Such State semiotics, according to Deleuze–Guattarian concepts, is distinguished as a signifying regime of signs characterized by its universal deception and regulated by State-controlled interpretations, facialized centres, and a high degree of deterritorializations. We examine the thresholds of territoriality-deterritorialization relations and expressions of amber signs during the Latvian nation-state’s and the Soviet Union’s semiotic regimes, conceptualized as indexes, symbols and icons. By tracing and mapping of these territorialisation movements we enrich our understanding of how effective the created semiotics are, and in what variety of forms and territorialities, including linguistic, craftsmanship, and varied place makings, they are expressed in a particular regime. Such territorial perspective thus shifts the focus from what and why these signs mean (e.g., national identity, homeland) to where, when and how (e.g., dynamics of various State’s territorialities) they become operational. Among other national products that emit signs, amber proved to be most effective in the functioning of State’s signifying semiotics in Latvia, representing thoroughly the strangleholds and the continuity of such deceptive semiotics. 相似文献
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Elga Apsīte Oļģerts Nikodemus Guntis Brūmelis Ainis Lagzdiņš Didzis Elferts Zigmārs Rendenieks 《水文科学杂志》2017,62(15):2558-2570
The aim of the study was to determine the effects of climate variability, agricultural land drainage and afforestation of agricultural land on river discharge. The study was conducted in the Vienziemīte stream basin (6 km2), where discharge was monitored on a daily basis during the time period of 1946–2010. In the stream basin, natural afforestation of agricultural land began in the 1950s, and in the mid-1970s artificial drainage systems were installed in all agricultural land (70% of the total basin area). Climate variability and artificial drainage were the main factors observed to be affecting stream discharge. The changes were most evident in annual and seasonal mean, minimum and maximum streamflow. There was no effect of afforestation of agriculture land on stream discharge. 相似文献
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Southwest China and Southeast Asia: towards sustainability through cooperative development and management of international rivers * 总被引:1,自引:0,他引:1
HE Daming Yunnan Institute of Geography Yunnan Kunming CHINA Dept. of Geography the University of Memphis Memphis TN USA Hsiange te Kung Dept. of Geography the University of Memphis Memphis TN USA 《地理学报(英文版)》1998,(3)
I.InternationalRiversandtheLancangMekongRiverInternationalriversaredefinedastheriverswhichflowacrostwoortwomorecountries.Upt... 相似文献
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An evaluation of the implicit management procedure used for some ICES roundfish stocks 总被引:1,自引:5,他引:1