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521.
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   
522.
523.
Lists of macrolepidopterans inhabiting the Southern, Middle, and Polar Urals have been used for analyzing the relationship between the species richness of these insects with that of the families of plants on which their larvae feed. The results have shown that this factor in the Southern Urals accounts for approximately 75% and 65% of variation in the species richness of lepidopterans on woody and herbaceous plants, respectively. In the Polar Urals, this correlation is markedly weaker. Latitudinal trends in trophic preferences of individual lepidopteran taxa have been revealed. Probable causes of changes in the relative abundance of lepidopterans north of the forest zone are discussed.  相似文献   
524.
The results of radiometric and haematological studies of striped field mice (Apodemus agrarius) sampled over the years 1995-2003 from the territory of the preserved radioactive waste burial (RWB), which is located in the Moscow recreation forest "Kuzminki", are presented and discussed in the paper. It was shown that the level of 90Sr-90Y content in mice sampled from the RWB area varies within the range of 0-1200 Bq/kg with an average of 98.7+/-21.5 Bq/kg. The content of 90Sr-90Y in the body of 80% of the mice sampled from the RWB area was below 100 Bq/kg. Only in 4% of the sampled mice, the 90Sr-90Y specific radioactivity was above 300 Bq/kg. Haematological indications of the animals sampled from the RWB area were within the range of normal physiological fluctuations. Nevertheless, a slight but statistically significant increase in the average amount of erythrocytes and the average percentage of banded neutrophils was registered in peripheral blood of the mice.  相似文献   
525.
The luminescence of quartz extracted from recently fired building material is known to detect doses of few mGy and can be successfully employed in the case of large scale radiation exposures due to nuclear accidents or terrorist acts. One brick and two tiles (50-80 years range) collected from an urban settlement were used to test the realistic minimum detectable dose limits of retrospective luminescence dosimetry. Independent methods like alpha counting, beta dosimetry, gamma spectrometry and flame photometry were used for the annual dose assessment. Two approaches were employed for the evaluation of the total accrued dose: regenerative dose and additive dose. The former allows the assessment of doses due to anthropogenic sources of radiation as low as approximately 12 mGy by using 10-year-old samples, but it can be applied only in samples showing no sensitisation. The latter can be applied to any sample, however, the related uncertainty is higher and minimum detectable anthropogenic dose in young samples amounts to 20 mGy.  相似文献   
526.
Air quality is managed in Great Britain via an effects-based, risk management process designed to provide a dynamic solution to public health issues associated with elevated concentrations of seven specified air pollutants. This paper is concerned with an examination and evaluation of the process of Local Air Quality Management (LAQM) in Great Britain from the late 1980s to date as a risk management process. The statutory basis of LAQM process is provided by the Environment Act 1995. The Act provides a framework in which national and local actions are required to identify and remediate areas of poor air quality. Within this framework, the implementation of the process at national and local levels is considered, leading to an identification and assessment of risks in the formulation and implementation of air quality management policy and practice. Local Authorities began the process of Review and Assessment in 1999 and the first round of the process concluded in 2001. Following this, some 129 Local Authorities declared one or more Air Quality Management Areas (AQMAs). The Review and Assessment elements of the framework were subjected to an evaluation in 2001 and the essential elements of it were confirmed as fit for purpose. The evaluation led to a confirmation of the process of LAQM but also a simplification based on the experience of Round 1. Now, a two step process is required comprising of an Updating and Screening Assessment and, where a risk of exceeding an Air Quality Objective (AQO) is identified, a Detailed Assessment follows. The Government has identified a time scale for Review and Assessment through to 2010 and also introduced the requirement of a regular Progress Report in order that a Local Authority is able to address routine matters of air quality management. The risks inherent in epidemiological or scientific uncertainty are factored into the LAQM process at an early stage of the process and, by identifying the risks and subjecting them to regular review, the process provides a 'level playing field' across spatial and temporal scales. Whilst the process of LAQM described in this paper has been developed for Great Britain, the generic elements of the process are applicable to other countries challenged by air pollution problems which require both national and local action to resolve them.  相似文献   
527.
Multi-element content and uranium (U) isotopes were investigated in the lichen Hypogymnia physodes (native and transplants) sampled across a 60-km transect, centred on Karabash smelter town, from Turgoyak Lake (SW) to Kyshtym (NE) to investigate the origin of U. Kyshtym was the site of a major nuclear accident in 1957. (234)U/(238)U activity ratios in native thalli sampled during July 2001 were within the natural isotopic ratio in minerals. Uranium/thorium (U/Th) ratios were higher in native thalli towards the NE (average 0.73) than those in the SW (average 0.57). Element signatures in native thalli and transplants suggest U was derived from fossil fuel combustion from Karabash and sources lying further to the east. Systematic and significant U enrichment indicative of a nuclear fuel cycle source was not detected in any sample. Element signatures in epiphytic lichen transplants and native thalli provide a powerful method to evaluate U deposition.  相似文献   
528.
There is a continual supply of new experimental data that are relevant to the assessment of the potential impacts of nuclear fuel waste disposal. In the biosphere, the traditional assessment models are data intensive, and values are needed for several thousand parameters. This is augmented further when measures of central tendency, statistical dispersion, correlations and truncations are required for each parameter to allow probabilistic risk assessment. Recent reviews proposed values for 10-15 key element-specific parameters relevant to (36)Cl, (129)I, (222)Rn, (226)Ra, (237)Np and (238)U, and some highlights from this data update are summarized here. Several parameters for Np are revised downward by more than 10-fold, as is the fish/water concentration ratio for U. Soil solid/liquid partition coefficients, Kd, are revised downward by 10-770-fold for Ra. Specific parameters are discussed in detail, including degassing of I from soil; sorption of Cl in soil; categorization of plant/soil concentration ratios for U, Ra and Np; Rn transfer from soil to indoor air; Rn degassing from surface water; and the Ca dependence of Ra transfers.  相似文献   
529.
Studies on speckled alder trees in an alder forest of grass-herb type in the northern taiga subzone of Northern Karelia have shown that specific features of the seasonal growth of shoots, leaves, and stems in these trees depend on a number of ecological factors, with air temperature playing the main role.  相似文献   
530.
Geometric morphometrics has been used to reveal coupled geographic variation in the mandible shape in two sympatric rodent species, the pygmy wood mouse (Sylvaemus uralensis Pall.) and bank vole (Myodes glareolus Pall.), in the Southern Urals. It has been shown that syntopic samples synchronously collected from the local communities of these species usually display similar, parallel, and unidirectional morphological changes as demonstrated by comparison of species pairs from different localities. The degree of concordance in geographic variation of the species makes it possible to estimate their coevolutionary potential within local communities: the wider the range of ecological conditions under which parallel variation of sympatric species is observed, the higher is their coevolutionary potential.  相似文献   
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