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Morphophysiological and anatomical characters of needles that are used for characterizing infraspecific taxa have been studied in Scotch pine geographic cultures established in the forest-steppe zone of Siberia. Variation in these characters has been revealed, which reflects the polymorphic structure of the species and the effect of natural selection on the composition of populations in new natural-cimatic conditions.  相似文献   
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Elements of carbon balance of oligotrophic bogs were studied using an example of the landscape profile of the Klyuch River in 1998–2000. Carbon balance was preliminarily calculated taking into account the biological productivity, release of carbon dioxide and methane, and carbon outflow with bog waters. Based on the data obtained on the carbon inflow and outflow, the conclusion was made concerning the progressive peat formation in the region studied.  相似文献   
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Within the last few years, uncleared solid wastes, in the form of heaps, have become a common sight in many Nigerian streets and open spaces. In order to assess the magnitudes of these wastes, a survey of selected 15 Nigerian cities was conducted for 2 months in 1982 with a team of 116 enumerators. It was found that the volumes of these uncleared wastes ranged from about 2 × 106 kg/yr to as high as 56 × 106 kg/yr in the cities studies. It was also found that the areas within a radius of 0.5 km of the city centres accounted for about 40% of these uncleared volumes of solid wastes.As distances increased from the city centres, the volumes of these wastes tended to decline. Therefore, it was determined that the main problem areas for uncleared solid wastes are in and around the city centres. These areas should demand special attention by city waste disposal agents.  相似文献   
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The methodology for estimating radiocaesium distribution between solid and liquid phases in lakes is applied for three prealpine lakes: Lake Constance (Germany), Lake Lugano (Switzerland) and Lake Vorsee (Germany). It is based on use of the exchangeable distribution coefficient and application of the exchangeable radiocaesium interception potential (RIPex). The methodology was tested against experimental data. Good agreement was found between estimated and measured 137Cs concentrations in Lake Constance and Lake Lugano, whereas for Lake Vorsee a discrepancy was found. Bottom sediments in Lake Vorsee are composed mainly of organic material and probably cannot be described in terms of the specific sorption characteristics attributed to illitic clay minerals.  相似文献   
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