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21.
The numerical evaluation of selected PCB congener (28, 118, 153, 180) transport over the Northern Hemisphere is carried out for 1996 using MSCE-POP model. This model is a multicompartment three-dimensional one and includes various environmental media such as the atmosphere, soil, vegetation, seawater, and sea ice. The spatial resolution is 2.5 degrees x2.5 degrees for all media except marine one (1.25 degrees x1.25 degrees ). The main model output information is deposition fluxes, spatial distribution of concentrations in environmental media, pathways and source-receptor relationships. Calculation results are analysed for the whole hemisphere and the Arctic region. In particular, this gives an opportunity to estimate the contributions of individual emission source groups to the Arctic pollution. The reliability of the model assessment is analysed by comparison between calculated and observed data.  相似文献   
22.
The model of random population dynamics in a sampling site returns geometric distribution of longevities of continuous presence (=persistence) and Poisson distribution of the presence–absence transitions. This discrete-time stochastic process describes the presence–absence pattern observed in the beetles surveyed 6 years on Mount Carmel, Israel. Homogeneous pools of species mostly on the Families rank, exhibit the predicted by the model patterns. Conformity to an ergodic hypothesis is the criterion of ecological homogeneity. This criterion assumes the equivalence of short-term behavior of entire pool and long-term behavior of any species from this pool. The pool of all 801 species of Order Coleoptera does not match the model. Thus a taxon of an arbitrary rank may not be considered a priory as a unit of ecological study. Determined from field data parameters of the model are biased and magnitude of the bias depends on longevity of the survey. Parameter of distribution depends also on species tolerance, which is the level adaptation of given species to given environment in given time interval. Random process of species turnover may be considered as a game of species to gain their presence against deteriorative fluctuations of environmental conditions.  相似文献   
23.
With the advancement of computational systems and the development of model integration concepts, complexity of environmental model systems increased. In contrast to that, theory and knowledge about > environmental systems as well as the capability for environmental systems analyses remained, to a large extent, unchanged. As a consequence, model conceptualization, data gathering, and validation, have faced new challenges that hardly can be tackled by modellers alone. In this discourse-like review, we argue that modelling with reliable simulations of human-environmental interactions necessitate linking modelling and simulation research much stronger to science fields such as landscape ecology, community ecology, eco-hydrology, etc. It thus becomes more and more important to identify the adequate degree of complexity in environmental models (which is not only a technical or methodological question), to ensure data availability, and to test model performance. Even equally important, providing problem specific answers to environmental problems using simulation tools requires addressing end-user and stakeholder requirements during early stages of problem development. In doing so, we avoid modelling and simulation as an end of its own.  相似文献   
24.
Journal of Material Cycles and Waste Management - Current management for drinking water treatment sludge and glass waste is insufficient, and a new method is needed. We sought to develop a new...  相似文献   
25.
This study describes a novel wastewater treatment technology suitable for small remote northern communities. The technology is based on an enhanced biodegradation of organic carbon through a combination of anaerobic methanogenic and microbial electrochemical (bioelectrochemical) degradation processes leading to biomethane production. The microbial electrochemical degradation is achieved in a membraneless flow-through bioanode–biocathode setup operating at an applied voltage below the water electrolysis threshold. Laboratory wastewater treatment tests conducted through a broad range of mesophilic and psychrophilic temperatures (5–23 °C) using synthetic wastewater showed a biochemical oxygen demand (BOD5) removal efficiency of 90–97% and an effluent BOD5 concentration as low as 7 mg L?1. An electricity consumption of 0.6 kWh kg?1 of chemical oxygen demand (COD) removed was observed. Low energy consumption coupled with enhanced methane production led to a net positive energy balance in the bioelectrochemical treatment system.  相似文献   
26.
The Rybinsk Reservoir (Russia) is the largest artificial waterbody in Europe (4550 km2) and provides drinking water for population of the cities located along the coast line. Industrialization in Cherepovets at the northeastern portion of the reservoir, including one of the largest metallurgical facilities in Europe, has resulted in chemical contamination of the reservoir. The extent of polychlorinated biphenyls (PCB) contamination in bream liver, a common fish species, taken from six locations in the Rybinsk Reservoir and Volga River, and biochemical and morphometric biomarkers of fish health were investigated. Liver PCB concentrations ranged from non-detected to 3.4 microg/g wet wt of liver, with the greatest concentrations found in fish taken near the industrialized area in Sheksna Reach of Rybinsk Reservoir. The source of the bream contamination is the PCB pollution of bottom organisms and sediments conditioned with industrialization facilities of Cherepovets. The patterns of the PCB congeners in the livers of bream taken near Cherepovets were similar at all of the stations that were sampled around the reservoir and Volga River. Among the common fish health biomarkers used only liver total ChE activity and liver-somatic index in bream near Cherepovets can reflect environmental pollution. Other morphometric (FCF, Clark's condition factors, and spleen-somatic index) and biochemical (protein content and acetylcholinesterase activity in the brain) biomarkers related with fish health varied among locations, but were not correlated to the concentrations of PCBs in the bream livers.  相似文献   
27.
28.
The systems approach permits us to analyze national security as a cluster of interconnected elements, in which the environmental dimension appears to be the most important one. The environmental problem is divided into two main aspects: environmental security per se and the impact of environment on the overall status of a nation's security. It is argued here that the quality of life and health serve as both the main objective and the principal criterion of environmental security in a social system. Indices of these two factors are used in this article as indicators of the state of this type of security. They confirm that vast areas of Russia, the Ukraine, and Central Asia (especially the Aral Sea region) should be considered as presenting a substantial risk to local people and even producing global impacts on both natural and man-made systems. Environmental factors that destabilize national security are also divided into two groups: those that impact social systems directly and negatively (mainly natural disasters) and technological and sociopolitical agents that cause indirect impacts, in both war and peace time, as well as in the civil and military sectors of the economy. Developments in the former Soviet Union (the Commonwealth of Independent States) are used as an illustration of the consequences that such impacts may have on the status of national security.  相似文献   
29.
Transcervical cell (TCC) samples have been shown to contain fetal cells amenable to molecular analysis. However, the presence of ‘contaminating’ maternal cells limits their use for prenatal diagnoses. In this report we show that clumps of fetal cells can be isolated from transcervical samples by micromanipulation and tested by fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR). Out of 129 clumps, isolated from mucus aspirates and transcervical lavages from 29 patients, 29 clumps from 11 patients were found to be exclusively of fetal origin as judged by the detection of chromosome 21-specific polymorphic DNA markers and Y-derived DNA sequences by PCR and FISH. One case of a male triploid fetus, diagnosed by the analysis of TCC samples obtained by mucus aspiration and lavage, was confirmed by testing clumps of cells isolated by micromanipulation.  相似文献   
30.
An i(Yp) is a rare marker chromosome. We present a case of de novo 46,X,i(Yp) detected prenatally in an amniotic fluid specimen. Fluorescence in situ hybridization (FISH) studies using a panel of Y-specific biotinylated DNA probes identified the marker chromosome as i(Yp). Comparative genomic hybridization (CGH) studies further confirmed the diagnosis. Upon pregnancy termination, external examination of the fetus revealed a generally well-developed male fetus with slight facial dysmorphism and prominent rocker-bottom feet. The molecular cytogenetic data in this case proved very useful in genetic counselling and served as a good example illustrating the important role of molecular techniques for accurate identification of marker chromosomes.  相似文献   
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