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Khalid A. Al-Ghanim Zubair Ahmad Hmoud F. Al-Kahem Al-Balawi Fahad Al-Misned Shahid Maboob El-Amin M. Suliman 《中国海洋湖沼学报》2016,34(1):109-117
Specimens of Clarias gariepinus were treated with lethal (70, 75, 80, 85, 90, and 95 mg/L) and sub-lethal concentrations (8, 12 and 16 mg/L) of uranyl acetate, a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell (RBC) and white blood cell (WBC) counts, haemoglobin (Hb) concentration and haematocrit (Hct) values were decreased. Different blood indices like mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration (Ca) was declined in the blood of exposed fish whereas magnesium (Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on Clarias gariepinus and causes changes in the biochemical and hematological parameters of the fish. 相似文献
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KhanA ZubairM AliR 《湿地科学》2005,3(1):21-26
1 INTRODUCTIONConstructedwetlandsplayanimportantroleinthereductionofnutrients,particularlyphosphorous,fromenteringintothewaterways .Excessivelevelsofphosphoroushavebeenidentifiedasamajorcon tributortoblue greenalgalbloomsinwaterways.Anumberofresearchprog… 相似文献
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The present study assesses anthropogenic disturbances and their impacts on the vegetation in Western Himalaya, India on the basis of various disturbance parameters such as density, Total Basal Cover (TBC) of cut stumps, lopping percentage and grazing intensities. On the basis of canopy cover and frequency of disturbances (%), the studied forests were divided into highly disturbed (HD), moderately disturbed (MD) and least disturbed (LD) categories. The HD forests had the lowest canopy cover, lowest density and lowest TBC and the LD had the highest canopy cover, highest density and highest TBC. The MD forests occupied the intermediate position with respect to these parameters. Species richness was least in HD forests, highest in one of the MD forests while LD forest occupied an intermediate position. The percentage of regenerating species was lowest (54%) in HD and highest (72%) in MD. The density of seedlings and saplings was higher in one of the MD forests as compared to HD and LD. We concluded that the moderate disturbances do not affect the vegetation adversely; however the increased degree of disturbance causes loss in plant diversity; affects regeneration and changes community characteristics. Construction of hydroelectric projects at various places in the study area was found to be one of the most important sources of anthropogenic disturbances in addition to the routine anthropogenic disturbances like grazing, fuelwood collection and fodder extraction. If all proposed dams in the Indian Himalaya are constructed combined with weak national environmental impact assessment and implementation, it will result in a significant loss of species. Therefore, various agents of disturbances should be evaluated in cumulative manner and any developmental activities such as hydropower projects, which trigger various natural and anthropogenic disturbances, should be combined with proper cumulative environmental impact assessment and effective implementation to minimise the anticipated loss of vegetation. 相似文献
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L. Zubair 《Theoretical and Applied Climatology》2002,71(1-2):119-127
Summary Hourly measurements of surface winds at Sita Eliya (6° 58′ N, 80° 46′ E, 1860 m a.s.l.) located atop the North-South mountain ridge in Sri Lanka were analyzed to investigate the diurnal and seasonal variation
in the wind climate. Surface winds are dominated by the monsoon regimes, with Northeasterlies from November to January, Southwesterlies
from February to May and Westerlies and Northwesterlies from June to October. Through most of the year, the average wind speed
is around 6–8 m/s. However from June to August, it is around 10–14 m/s. Wind in June is gusty due the location of the low-level
Easterly jet over Sri Lanka. The wind undergoes a reversal in both zonal and meridional directions in March and November coincident
with the migration of the Inter-Tropical Convergence Zone. Notwithstanding the period from May to September being designated
as the Southwest monsoon, the wind is from West, South-West-West and North-North-West. During the Southwest monsoon, wind
speed during the night is nearly as high as that during the day. This anomalous diurnal variation in wind speeds may be related
to orographic influences. The high wind speeds at Sita Eliya, in conjunction with the moderate diurnal and seasonal variability
in wind speed, is suitable for wind-energy generation.
Received January 2, 2001 Revised May 26, 2001 相似文献
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Sarith P.P. Mahanama Randal D. Koster Rolf H. Reichle Lareef Zubair 《Advances in water resources》2008
The two main contributors to streamflow predictability at subseasonal to seasonal timescales in tropical regions are: (i) the predictability of meteorologic (particularly precipitation) anomalies, and (ii) the land surface soil moisture state at the start of the forecast period. Meteorological predictions at subseasonal timescale are usually fraught with error and may not be dependable. The accurate initialization of soil moisture, as obtained through real-time land data analysis, may provide skill in subseasonal to seasonal streamflow prediction, even when the prediction skill for rainfall is small. 相似文献
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We discuss the Bianchi type I model with perfect fluid as matter content in f(R,T) gravity, where R is the Ricci scalar and T is the trace of the energy-momentum tensor. We obtain exact solutions of the field equations employing the anisotropic feature of spacetime for two expansion laws namely exponential and power expansions. The physical and kinematical quantities are examined for both cases in future evolution of the universe. We also explore the validity of null energy condition and conclude that our solutions are consistent with the current observations. 相似文献