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61.
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Simple flow models are inadequate for understanding short-run price behaviour in non-fuel mineral markets. In this note the author derives a simple model of mineral price behaviour in terms of stocks, and shows how this may successfully explain some short-term features of mineral price behaviour.  相似文献   
63.
The idea of confronting several hundred managers, politicians, and academics with 20 or so energy experts and celebrities to determine whether supplying the industrial world with energy is fundamentally a matter for the private sector or the state, may seem at first like an affront to common sense. After all, conferences, including those convened under the auspices of distinguished foundations, usually do not have any executive powers; and considering the uneven quality of the presentations, I suspect that the proceedings of this particular assembly will only have a limited readership in those spacious rooms adjoining the corridors of power. However, for reasons discussed below, this conference was a useful exercise. Energy Policy in the Market Economy, arranged by the Institut für Wirtschafts- und Gesellschaftspolitik, and sponsored by the Konrad-Adenauer-Stiftung, Bonn-Bad Godesberg, Germany, 29–30 May 1979.  相似文献   
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Bovilla Lake is a reservoir constructed 12 years ago for supplying the city of Tirana (Albania) mainly with drinking water. It has a surface area of 4.6 km(2), a maximum depth of originally 60 m and is monomictic with a stratification period from early spring to end of October. The lake is oligotrophic with low nutrient concentrations (e.g. SRP in spring about 8 μg L(?-1)) and minor oxygen depletion in the hypolimnion during thermal stagnation. The lake is highly turbid due to severe particle import by several rivers during rain periods. This led to a massive deposition of sediments, lifting the maximum depth to 45 m in 2008. Furthermore, the photic zone reached hardly more than 10 m. Algal species diversity is high; however, diatoms from the genus Cyclotella dominate most of the year both in numbers and biomass. Our study describes for the first time the hydrography and limnology of the Bovilla Reservoir.  相似文献   
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