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排序方式: 共有93条查询结果,搜索用时 15 毫秒
31.
Bob McKercher 《GeoJournal》1993,29(3):307-313
Australia's conservation and parks organisations have become actively involved in the debate over tourism use of national parks and their associated wilderness areas. To date, at least seven organisations have produced at least ten formal policy statements and submissions. This paper presents an analysis of these policy statements.The policies reviewed use a narrow definition of tourism, based on the presence or absence of commercial, private sector activity. If commercial activity exists, then tourism exists; if not, then it is considered to be recreation. This distinction reflects the widely held opinion among many environmentalists that non-commercial use of national parks is acceptable, but that commercial use is essentially unacceptable, even though the groups may be participating in the same activity. The author argues that while making a number of valuable suggestions, these policies suffer from major conceptual flaws that minimise their contribution to the debate on acceptable human uses of parks.The author concludes by making a number of recommendations to rectify the conceptual flaws inherent in the policies. 相似文献
32.
Use of Systematic, Palaeoflood and Historical Data for the Improvement of Flood Risk Estimation. Review of Scientific Methods 总被引:2,自引:0,他引:2
Gerardo Benito Michel Lang Mariano Barriendos M. Carmen Llasat Felix Francés Taha Ouarda Varyl Thorndycraft Yehouda Enzel Andras Bardossy Denis Coeur Bernard Bobée 《Natural Hazards》2004,31(3):623-643
The catastrophic floods recently occurring in Europe warn of the critical need forhydrologic data on floods over long-time scales. Palaeoflood techniques provideinformation on hydrologic variability and extreme floods over long-time intervals(100 to 10,000 yr) and may be used in combination with historical flood data (last1,000 yr) and the gauge record (last 30–50 yr). In this paper, advantages anduncertainties related to the reconstruction of palaeofloods in different geomorphologicalsettings and historical floods using different documentary sources are described.Systematic and non-systematic data can be combined in the flood frequency analysisusing different methods for the adjustment of distribution functions. Technical toolsintegrating multidisciplinary approaches (geologic, historical, hydraulic and statistical)on extreme flood risk assessment are discussed. A discussion on the potential theoreticalbases for solving the problem of dealing with non-systematic and non-stationary data ispresented. This methodology is being developed using new methodological approachesapplied to European countries as a part of a European Commission funded project (SPHERE). 相似文献
33.
Bruce Bassett, Bob Nichol and Daniel J Eisenstein explain why the Wide-Field Multi-Object Spectrograph will need to look so far into the universe, over such a wide area, in order to map sound waves from the dawn of time. 相似文献
34.
Urmilla Bob 《GeoJournal》2004,61(3):291-300
This article contributes to a greater understanding of the linkages between women's roles, responsibilities and their use
of technology in poor rural communities. The ways in which poor rural women conceptualize technology is examined. Furthermore,
how they use their knowledge and skills to develop, modify and adapt the techniques and technical processes in which they
are involved are also explored. Additionally, the links between indigenous and modern technologies in relation to gender considerations
in poor rural contexts are examined. This article draws from findings of primary research undertaken in two marginalized rural
communities in Kwazulu-Natal, South Africa. The study reveals that the use of technologies are highly gendered and differentiated
among women. Poor rural women utilize a range of technologies in both productive and reproductive activities which are central
to their livelihood strategies, especially at the household level. Furthermore, although women are adapting and innovating
technologies their expertise remains largely unrecognized. A range of problems and constraints exist which limit women's access
to and use of technologies. A key tension identified in the study is that between the use of locally-based, indigenous technologies
and modern, external technologies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
35.
36.
Accurately mapped locations within multi-unit properties are useful for several organizations in today's society. Published work on geocoding methods either require detailed location reference data or does not apply to multi-unit buildings. In this research, a generalizable method is realized to map apartment addresses to their explicit locations without access to indoor location reference data based on publicly available address- and geospatial-building information. The performance of this approach is measured by conducting a comparative study between a linear interpolation baseline and gradient-boosted decision trees model. The proposed method can successfully geocode addresses across different building shapes and sizes. Furthermore, the model significantly outperforms the baseline in terms of positional accuracy proving the feasibility of approximating apartment locations by their address- and geospatial-building information. 相似文献
37.
Neva A. Fowler‐Gerace Kimberly T. Tait Desmond E. Moser Ivan Barker Bob Y. Tian 《Meteoritics & planetary science》2016,51(6):1125-1135
The mechanism by which olivine grains became embedded within iron‐nickel alloy in pallasite meteorites continues to be a matter of scientific debate. Geochemical and textural observations have failed to fully elucidate the origin and history of the olivine crystals; however, little research attention has been devoted to their crystallographic orientations within the metal matrix. Using electron backscatter diffraction, we have collected crystallographic orientation data for 296 crystals within ~65 cm2 sample surface from Springwater. Though no global crystallographic preferred orientation exists, very low misorientations are observed among [100] axes of olivine crystals within specific texturally defined domains. Combined with a thorough characterization of large‐scale Springwater textures, the definitively nonrandom spatial distribution of olivine orientations provides clues regarding the nature of the olivine's initial formation environment as well as the sequence of events subsequent to metal incorporation. 相似文献
38.
We present a method for inversion of fracture compliance matrix components from wide‐azimuth noisy synthetic PS reflection data and quantitatively show that reflection amplitude variations with offset and azimuth for converted PS‐waves are more informative than P‐waves for fracture characterization. We consider monoclinic symmetry for fractured reservoir (parameters chosen from Woodford Shale), which can be formed by two or more sets of vertical fractures embedded in a vertically transverse isotropic background. Components of effective fracture compliance matrices for a medium with monoclinic symmetry are related to the characteristics of the fractured medium. Monte Carlo simulation results show that inversion of PS reflection data is more robust than that of PP reflection data to uncertainties in our a priori knowledge (vertically transverse isotropic parameters of unfractured rock) than PP reflection data. We also show that, while inversion of PP reflections is sensitive to contrasts in elastic properties of upper and lower media, inversion of PS reflections is robust with respect to such contrasts. 相似文献
39.
Longitudinal variations of energetic charged particle precipitation into the jovian sub-auroral atmosphere are modeled based on weak diffusion scattering and variations in the local loss-cone size associated with asymmetries in the VIP-4 magnetic field model. Our scattering model solutions suggest that low latitude observations of enhanced H3+ and X-ray emissions are at least partially due to precipitating energetic particles. The correlation between model results and observations is best in the northern hemisphere at low L (1.5), where the surface magnetic field variation is largest and observations have the highest resolution. Weaker correlations in the southern hemisphere and at higher latitudes, particularly for H3+ emissions, are likely due to the presence of other energy sources, lack of resolution in the observations and limitations in the sub-auroral surface magnetic field model. 相似文献
40.