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排序方式: 共有193条查询结果,搜索用时 31 毫秒
111.
Growing up with rivers? Rivers in London children's worlds 总被引:1,自引:0,他引:1
Susan Tapsell Sylvia Tunstall Margaret House John Whomsley & Phillip Macnaghten 《Area》2001,33(2):177-189
This paper presents the results from exploratory research which set out to investigate London children's perceptions and uses of river environments. Mainly qualitative, multi-method research was carried out in four primary schools with children aged 9–11, focusing on two rivers near to the schools. Rivers were found to be marginal to the children's everyday lives and outdoor play, being perceived as polluted, neglected, and initially dangerous places. However, when experienced on visits observed as part of the research, some of these perceptions changed and rivers were also found to afford many special activities and experiences for the children. The visits were generally seen to have a positive effect on the children's perceptions of rivers, at least in the short term. This suggests that, if managed appropriately, rivers could be potentially rewarding play areas for children. Moreover, children could provide valuable input for river managers in suggesting ways of improving suitable local rivers for increased recreational uses. 相似文献
112.
A study of the effects of soil-pile-structure interaction on the response of rotational shell structures supported by a group of vertical piles is presented. The interaction effects are included in the dynamic analysis through the development of a frequency dependent boundary system at the interface between the shell and the underlying foundation. The substructure method is used to simplify the connection problem between the shell and the pile foundation. A free vibration analysis of a cooling tower is carried out to investigate the dynamic properties of rotational shells with four different foundation stiffnesses. The effects of soil-pile-structure interaction on the response in the shell are demonstrated by a complex response analysis of a cooling tower. 相似文献
113.
Qiang Cai Gerard Rushton Budhendra Bhaduri Edward Bright Phillip Coleman 《Transactions in GIS》2006,10(4):577-598
The objective of this research is to compute population estimates by age and sex for small areas whose boundaries are different from those for which the population counts were made. In our approach, population surfaces and age‐sex proportion surfaces are separately estimated. Age‐sex population estimates for small areas and their confidence intervals are then computed using a binomial model with the two surfaces as inputs. The approach was implemented for Iowa using a 90 m resolution population grid (LandScan USA) and U.S. Census 2000 population. Three spatial interpolation methods, the areal weighting (AW) method, the ordinary kriging (OK) method, and a modification of the pycnophylactic method, were used on Census Tract populations to estimate the age‐sex proportion surfaces. To verify the model, age‐sex population estimates were computed for paired Block Groups that straddled Census Tracts and therefore were spatially misaligned with them. The pycnophylactic method and the OK method were more accurate than the AW method. The approach is general and can be used to estimate subgroup‐count types of variables from information in existing administrative areas for custom‐defined areas used as the spatial basis of support in other applications. 相似文献
114.
115.
Phillip H. Shelley 《Geoarchaeology》1993,8(1):59-72
The methods and techniques presented provide a means for evaluating raw material characteristics in those situations where secondary deposits of lithic materials were exploited for stone tool production. Those aspects of secondary deposits measured or estimated include size, form, roundness, crystallinity, homogeneity, and raw material frequency. A comparison and discussion of two sampled areas in eastern New Mexico demonstrate how these procedures can be used to elucidate meaningful archaeological information. © 1993 John Wiley & Sons, Inc. 相似文献
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117.
Ultra‐reduced phases in Apollo 16 regolith: Combined field emission electron probe microanalysis and atom probe tomography of submicron Fe‐Si grains in Apollo 16 sample 61500
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Phillip Gopon Michael J. Spicuzza Thomas F. Kelly David Reinhard Ty J. Prosa John Fournelle 《Meteoritics & planetary science》2017,52(9):1941-1962
The lunar regolith contains a variety of chemically reduced phases of interest to planetary scientists and the most common, metallic iron, is generally ascribed to space weathering processes (Lucey et al. 2006 ). Reports of silicon metal and iron silicides, phases indicative of extremely reducing conditions, in lunar samples are rare (Anand et al. 2004 ; Spicuzza et al. 2011 ). Additional examples of Fe‐silicides have been identified in a survey of particles from Apollo 16 sample 61501,22. Herein is demonstrated the utility of low keV electron probe microanalysis (EPMA), using the Fe Ll X‐ray line, to analyze these submicron phases, and the necessity of accounting for carbon contamination. We document four Fe‐Si and Si0 minerals in lunar regolith return material. The new Fe‐Si samples have a composition close to (Fe,Ni)3Si, whereas those associated with Si0 are close to FeSi2 and Fe3Si7. Atom probe tomography of (Fe,Ni)3Si shows trace levels of C (60 ppma and nanodomains enriched in C, Ni, P, Cr, and Sr). These reduced minerals require orders of magnitude lower oxygen fugacity and more reducing conditions than required to form Fe0. Documenting the similarities and differences in these samples is important to constrain their formation processes. These phases potentially formed at high temperatures resulting from a meteorite impact. Whether carbon played a role in achieving the lower oxygen fugacities—and there is evidence of nearby carbonaceous chondritic material—it remains to be proven that carbon was the necessary component for the unique existence of these Si0 and iron silicide minerals. 相似文献
118.
Marine protected management has gained acceptance as a way forward to achieve enhanced biodiversity outcomes. Simultaneously, co-management has gathered momentum as a mechanism to incorporate indigenous cultural aspirations within environmental management domains. Each management process has its own methodologies; when the two models intersect, they present a number of challenges to overall management outcomes. We review the journey of an indigenous co-management initiative within a marine protected area (MPA), the Great Barrier Reef World Heritage Area (GBRWHA), Australia, to explore how different management paradigms intersect with both negative and positive results. We argue that lessons learned from this initiative will help participants to adapt and innovate, so as to implement effective on ground management despite the region being a contested site. 相似文献
119.
For decades, the scientific community has conducted essential background research and developed appropriate modeling tools in support of an ecosystem-based approach to natural resource management. Resource managers and the public, however, lack a clear roadmap for working with scientists to move beyond the traditional single-species approach. With current management processes so strongly focused on working in a species-by-species framework, there are entrenched cultural and institutional challenges to shifting those processes toward ecosystem-based management. We propose using the integrated ecosystem assessment process to both develop new management ideas for a particular ecosystem, and to help shift public policy processes and perceptions to embrace ecosystem approaches to management. 相似文献
120.
Alexander Popp Steven K. Rose Katherine Calvin Detlef P. Van Vuuren Jan Phillip Dietrich Marshall Wise Elke Stehfest Florian Humpenöder Page Kyle Jasper Van Vliet Nico Bauer Hermann Lotze-Campen David Klein Elmar Kriegler 《Climatic change》2014,123(3-4):495-509
In this article, we evaluate and compare results from three integrated assessment models (GCAM, IMAGE, and ReMIND/MAgPIE) regarding the drivers and impacts of bioenergy production on the global land system. The considered model frameworks employ linked energy, economy, climate and land use modules. By the help of these linkages the direct competition of bioenergy with other energy technology options for greenhouse gas (GHG) mitigation, based on economic costs and GHG emissions from bioenergy production, has been taken into account. Our results indicate that dedicated bioenergy crops and biomass residues form a potentially important and cost-effective input into the energy system. At the same time, however, the results differ strongly in terms of deployment rates, feedstock composition and land-use and greenhouse gas implications. The current paper adds to earlier work by specific looking into model differences with respect to the land-use component that could contribute to the noted differences in results, including land cover allocation, land use constraints, energy crop yields, and non-bioenergy land mitigation options modeled. In scenarios without climate change mitigation, bioenergy cropland represents 10–18 % of total cropland by 2100 across the different models, and boosts cropland expansion at the expense of carbon richer ecosystems. Therefore, associated emissions from land-use change and agricultural intensification as a result of bio-energy use range from 14 and 113 Gt CO2-eq cumulatively through 2100. Under climate policy, bioenergy cropland increases to 24–36 % of total cropland by 2100. 相似文献