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The present research aims to derive the intrinsic vulnerability of groundwater against contamination using the GIS platform. The study applies DRASTIC model for Ahmedabad district in Gujarat, India. The model uses parameters like depth, recharge, aquifer, soil, topography, vadose zone and hydraulic conductivity, which depict the hydrogeology of the area. The research demonstrates that northern part of district with 46.4% of area is under low vulnerability, the central and southern parts with 48.4% of the area are under moderate vulnerability, while 5.2% of area in the south-east of district is under high vulnerability. It is observed from the study that lower vulnerability in northern part may be mostly due to the greater depth of vadose zone, deeper water tables and alluvial aquifer system with minor clay lenses. The moderate and high vulnerability in central and southern parts of study area may be due to lesser depth to water tables, smaller vadose zone depths, unconfined to semi-confined alluvial aquifer system and greater amount of recharge due to irrigation practices. Further, the map removal and single-parameter sensitivity analysis indicate that groundwater vulnerability index has higher influence of vadose zone, recharge, depth and aquifer parameters for the given study area. The research also contributes to validating the existence of higher concentrations of contaminants/indicators like electrical conductivity, chloride, total dissolved solids, sulphate, nitrate, calcium, sodium and magnesium with respect to groundwater vulnerability status in the study area. The contaminants/indicators exceeding the prescribed limits for drinking water as per Indian Standard 10500 (1991) were mostly found in areas under moderate and high vulnerability. Finally, the research successfully delineates the groundwater vulnerability in the region which can aid land-use policies and norms for activities related to recharge and seepage with respect to existing status of groundwater vulnerability and its quality.  相似文献   
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Lack of shrimp cell lines has hindered the study of pollutants which adversely affects shrimp health and its export value. In this context a primary haemocyte culture developed from Penaeus monodon was employed for assessing the cytotoxicity and genotoxicity of two heavy metal compounds, cadmium chloride and mercuric chloride and two organophosphate insecticides, malathion and monocrotophos. Using MTT assay 12?h IC(50) values calculated were 31.09?±?16.27?μM and 5.52?±?1.16?μM for cadmium chloride and mercuric chloride and 59.94?±?52.30?mg?l(-1) and 186.76?±?77.00?mg?l(-1) for malathion and monocrotophos respectively. Employing Comet assay, DNA damage inflicted by these pollutants on haemocytes were evaluated and the pollutants induced DNA damage in >60% of the cells. The study suggested that haemocyte culture could be used as a tool for quantifying cytotoxicity and genotoxicity of aquaculture drugs, management chemicals and pollutants.  相似文献   
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The possibility of magnesium oxide being the first species to nucleate in the cooling outflows around M stars has been investigated. By treating the formation of the seed nuclei as a homogeneous nucleation problem and using molecular dynamics data obtained with the 'compressible ion potential' for MgO, free energy calculations are performed to obtain an estimate of the population densities of MgO clusters of various sizes. It is found that a free energy barrier of at least hundreds of   k B T   would need to be climbed in order for MgO to nucleate in significant amount in typical circumstellar shells, hence ruling out MgO as a realistic candidate for the primary nucleating dust species. This is in agreement with a similar conclusion reached in earlier studies, although the present calculations are based on a much more robust potential model for MgO.  相似文献   
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Studies of sustained activity in the Koyna — Warna Seismic Zone have yielded several models of faults in the basement of the Deccan Traps inferred from geophysical and seismic signatures. There is however, a dearth of unambiguous surface manifestations of such faults, apart from the surface ruptures from the epicentral zone of the December, 1967 earthquake. We report for the first time, an exposed NW-SE trending reverse fault in the Deccan Trap basalts from this region.  相似文献   
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