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351.
The role of nitrilotriacetate in copper uptake by tobacco 总被引:1,自引:0,他引:1
In growth chamber experiments we studied the effect of nitrilotriacetate (NTA) on Cu uptake by tobacco (Nicotiana tabacum L.). Plants were exposed for 6 d to 126 microM Cu and 500 microM NTA in nutrient solutions without and with 10 g L(-1) montmorillonite. Approximately seven times less Cu was dissolved in the montmorillonite solutions than in the nutrient solutions alone. In the absence of NTA, montmorillonite effectively competed with plant roots for Cu, although Cu remained bound to the roots. Nitrilotriacetate increased Cu uptake and translocation into shoots of tobacco by a factor of 3.5 from the nutrient solution and by a factor of 26 from the montmorillonite nutrient solution. Neither growth reduction nor any other visible sign of Cu toxicity was found in the presence of NTA with Cu concentrations of 190 mg kg(-1) in the shoots. In the absence of NTA, high Cu concentrations in root samples led to a brownish discoloration of the roots. 相似文献
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354.
Community and farm forestry climate mitigation projects: case studies from Uttaranchal,India 总被引:1,自引:1,他引:1
N. Hooda M. Gera K. Andrasko J. Sathaye M. K. Gupta H. B. Vasistha M. Chandran S. S. Rassaily 《Mitigation and Adaptation Strategies for Global Change》2007,12(6):1099-1130
The methodologies for forest mitigation projects still present challenges to project developers for fulfillment of criteria
within the Clean Development Mechanism (CDM) or other such mechanisms for the purpose of earning carbon credits. This paper
systematically approaches the process of establishing carbon (C) stocks for baseline (BSL) and mitigation scenario (MSL) for
two case studies i.e., community and farm forestry projects in Uttaranchal, India. The analysis of various interventions shows that both projects present high carbon mitigation
potential. However, the C reversibility risk is lower in long-rotation pine and mixed species plantation on community lands.
The project is financially viable though not highly lucrative but the carbon mitigation potential in this ‘restoration of
degraded lands’ type of project is immense provided challenges in the initial phase are adequately overcome. C revenue is
an essential driver for investors in community projects. The short-rotation timber species such as Eucalyptus (Eucalyptus), Poplar (Populus) have high internal rates of return (IRR) and high carbon benefit reversibility potential due to fluctuations in market prices
of commodities produced. The land holdings are small and bundling is desired for projects to achieve economies of scale. The
methodological concerns such as sampling intensities, monitoring methodologies, sharing of benefits with communities and bundling
arrangements for projects need further research to make these projects viable. 相似文献
355.
356.
Rao PV Gupta N Bhaskar AS Jayaraj R 《Journal of environmental biology / Academy of Environmental Biology, India》2002,23(3):215-224
Many species of cyanobacteria (blue-green algae) produce secondary metabolites with potent biotoxic or cytotoxic properties. These metabolites differ from the intermediates and cofactor compounds that are essential for cell structural synthesis and energy transduction. The mass growth of cyanobacteria which develop in fresh, brackish and, marine waters commonly contain potent toxins. Cyanobacterial toxins or cyanotoxins are responsible for or implicated in animal poisoning, human gastroenteritis, dermal contact irritations and primary liver cancer in humans. These toxins (microcystins, nodularins, saxitoxins, anatoxin-a, anatoxin-a(s), cylindrospermopsin) are structurally diverse and their effects range from liver damage, including liver cancer to neurotoxicity. Several incidents of human illness and more recently, the death of 60 haemodialysis patients in Caruaru, Brazil, have been linked to the presence of microcystins in water. In response to the growing concern about the non-lethal acute and chronic effects of microcystins, World Health Organization has recently set a new provisional guideline value for microcystin-LR of 1.0 microg/L in drinking water. Cyanobacteria including microcystin-producing strains produce a large number of peptide compounds, e.g. micropeptins, cyanopeptolins, microviridin, circinamide, aeruginosin, with varying bioactivities and potential pharmacological application. This article discusses briefly cyanobacterial toxins and their implications on human health. 相似文献
357.
This study was concerned with an examination of the relationships among employee responses to the work setting. Responses in the work and nonwork spheres were examined, and an attempt made to determine the stability of the relationships across organizations. Data were obtained from 651 employees of five midwestern organizations using four data sources—structured interviews, on-the-job observations, supervisory ratings, and personnel records. The analysis indicated that, in general, employee reactions in the work and nonwork spheres loaded on separate factors, and that the relationships among employee responses were relatively stable across organizations. Some directions for future research on this issue are suggested. 相似文献
358.
B. K. Panigrahi A. Das Gupta 《Journal of the American Water Resources Association》1979,15(4):1168-1172
ABSTRACT: Double-mass analysis for checking consistency of a hydrological record is considered to be essential before taking it for analysis purpose. Because of increasing computer application in hydrological analyses, in the present paper, a simple and efficient method for the double-mass checking has been developed. The problem has been formulated in FORTRAN IV language and the basic steps and a computer output of the program are presented in a flow chart and a table. 相似文献
359.
Summary In this paper, pollutants in air, water and as solids which stem from the paper industry are discussed, and pollution abatement measures are suggested. The Pulp and Paper Industry is highly capital, material and energy intensive and return on investment is very low. This paper reviews some emerging international principles which are effective in reducing both effluent treatment costs per tonne of paper and the mill discharges, to levels where their environmental impacts become far less significant than at present.Mr Avijit Dey is a graduate in Chemical Engineering from Jadavpur University and at present is Design Engineer in the Paper and Process Cell of Development Consultants Ltd, 24-B Park Street, Calcutta 70016, India. Dr B. Sen Gupta is Reader in the Chemical Engineering Department of Jadavpur University, Calcutta. He obtained his BChE and PhD in Chemical Engineering from Jadavpur University and an ME in Chemical Engineering from the Indian Institute of Science, Bangalore. His research interests involve pulp and paper technology, water conservation and management, and pollution control. 相似文献
360.
Influence of chemical oxygen demand/total Kjeldahl nitrogen ratio and sludge age on nitrification of nitrogenous wastewater. 总被引:1,自引:0,他引:1
Four laboratory-scale biological nitrification units (influent total Kjeldahl nitrogen [TKN] = 1002 to 1062 mg/L) were operated at chemical oxygen demand (COD)/TKN ratios of approximately 0.5, 1.0,15, and 2.0 and at three different sludge ages of 30, 20, and 10 days to study the influence of COD/TKN, sludge age, COD loading, and TKN loading on nitrification and nitrifiers. Percent nitrification was found to increase with decreases in COD/TKN and increases in sludge age. The average nitrifier concentration increased from 460 mg/L at a COD/TKN of 2.22 and a sludge age of 10 days to 706 mg/L at a COD/TKN of 0.676 and a sludge age of 30 days. The nitrifier fraction was found to be higher at a lower COD/TKN and lower at a higher COD/TKN. The nitrifier fraction increased with the decrease in sludge age and COD loadings and the increase in TKN loadings. The effect of sludge age on the nitrifier fraction was amplified at a COD/ TKN of approximately 0.5 rather than at approximately 2.0. The nitrification rate (kilograms TKN oxidized per kilograms nitrifiers per day) was shown to be dependent on COD/TKN and sludge age. The activity performed by Nitrobacter was affected at all COD/TKN ratios studied as well as at a sludge age of 10 days. This was manifested by the accumulation of high levels of nitrite-nitrogen in the nitrified effluent. The presence of heterotrophs did not affect nitrification rates and the growth of nitrifiers, which were found to be beneficial. High sludge age and COD loadings resulted in a higher sludge volume index of more than 200 mL/g mixed liquor suspended solids. Microscopic examination showed filamentous structure of sludge under these conditions. It is concluded from the investigations that a sludge age of 30 days and a COD/TKN of approximately 1.0 are optimal to yield maximum nitrification and nitrifier growth rates for treating high-strength nitrogenous wastewater. 相似文献