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21.
Noor Faizah Fitri Md Yusof Nor Azam Ramli Ahmad Shukri Yahaya Nurulilyana Sansuddin Nurul Adyani Ghazali Wesam al Madhoun 《Environmental monitoring and assessment》2010,163(1-4):655-667
There are many factors that influence PM10 concentration in the atmosphere. This paper will look at the PM10 concentration in relation with the wet season (north east monsoon) and dry season (south west monsoon) in Seberang Perai, Malaysia from the year 2000 to 2004. It is expected that PM10 will reach the peak during south west monsoon as the weather during this season becomes dry and this study has proved that the highest PM10 concentrations in 2000 to 2004 were recorded in this monsoon. Two probability distributions using Weibull and lognormal were used to model the PM10 concentration. The best model used for prediction was selected based on performance indicators. Lognormal distribution represents the data better than Weibull distribution model for 2000, 2001, and 2002. However, for 2003 and 2004, Weibull distribution represents better than the lognormal distribution. The proposed distributions were successfully used for estimation of exceedences and predicting the return periods of the sequence year. 相似文献
22.
A number of mechanisms have been identified that can lead to (acute) aquatic toxicity. The assignment of compounds to a particular mechanism of action is important in the development and utilisation of (quantitative) structure-activity relationships ((Q)SARs) for ecotoxicity. Assignment to a mechanism can be difficult; however in 1992 Verhaar et al. published a series of structural rules which aimed to classify compounds according to mechanism of action. Recent interest has seen the Verhaar rules coded into freely available software such as Toxtree available from the European Chemicals Bureau. To date, a complete critical evaluation of these rules has been lacking. Therefore, the aim of this study was to evaluate the Toxtree implementation of the Verhaar rules using two well characterised aquatic toxicity datasets (Pimephales promelas and Tetrahymena pyriformis phenol databases) for which mechanisms of toxic action are well established. The present study highlights rule, and possible coding, errors that may lead to misclassifications. Improvements to both the rules and prediction architecture are suggested. In particular further rules to improve predictions for polar narcosis (class 2) are suggested. 相似文献
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Tran Thuan Van Nguyen Duyen Thi Cam Kumar Ponnusamy Senthil Din Azam Taufik Mohd Jalil Aishah Abdul Vo Dai-Viet N. 《Environmental Chemistry Letters》2022,20(2):1309-1331
Environmental Chemistry Letters - Pollution and diseases such as the coronavirus pandemic (COVID-19) are major issues that may be solved partly by nanotechnology. Here we review the synthesis of... 相似文献
25.
Predator-prey interactions between the larvacean Oikopleura dioica and bacterioplankton in enclosed water columns 总被引:3,自引:0,他引:3
The larvacean Oikopleura dioica Fol was fed 3H-labeled natural assemblages of marine bacterioplankton. Grazing rates ranged from <1 to >100 ml day-1 individual-1 and were highly dependent onlarvacean body size. These rates were combined with estimates of abundance of O. dioica in large floating enclosures with semi-natural populations (Controlled Ecosystems Populations Experiment, CEPEX) to determine the impact of the larvacean on the bacterial populations and to estimate the amount of bacteria ingested by the larvaceans. Apparently, O. dioica has minimal influence on the population dynamics of the free-living bacteria, although bacteria may form a substantial portion of the larvacean's diet. 相似文献
26.
R. E. Hodson F. Azam A. F. Carlucci J. A. Fuhrman D. M. Karl O. Holm-Hansen 《Marine Biology》1981,61(2-3):89-94
The distribution and activity of bacterioplankton, and the turnover of dissolved organic matter (DOM) were examined in McMurdo Sound, Antarctica. On the eastern side of the Sound, bacteria averaged 6.5×108 l-1, and turnover rates of dissolved adenosine triphosphate, D-glucose and l-leucine averaged 16, 116 and 124 h, respecitvely. These molecules as well as thymidine were taken up maximally from 0° to 5°C and near-maximally from -1.5° to 0°C, indicating bacterial adaptation to rapid turnover of dissolved organic matter at the ambient temperature. On the west side of the Sound, bacteria averaged only 0.65×108 l-1, and turnover times for adenosine triphosphate, D-glucose and lleucine averaged 59, 20454, and 3070 h, respectively. Total microbial adenosine triphosphate (an indicator of total microbial biomass) and chlorophyll a were also much lower at the western than at the eastern side stations. Moreover, no primary production could be detected at one western side station (New Harbor). Thus, in McMurdo Sound, the western side is highly oligotrophic, but the eastern side has an abundant active bacterioplankton, comparable to that of temperate coastal waters.Communicated by N. Holland, La Jolla 相似文献
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Bacterioplankton in the coastal euphotic zone: Distribution,activity and possible relationships with phytoplankton 总被引:7,自引:0,他引:7
Bacterioplankton were studied in the euphotic zone of the Southern California Bight, USA, with special attention to biological factors affecting bacterial distribution and activity. Measurements were made of bacterial abundance, thymidine incorporation into acid insoluble material, primary production (particulate and dissolved), chlorophyll, phaeopigments, total microbial ATP, particulate organic carbon and nitrogen, dissolved organic carbon, dissolved primary amines, and glucose and thymidine turnover rates. The data were analyzed by pairwise rank correlations with significance tested at the P<.005 level. Bacterial abundance and thymidine incorporation both declined progressively with increasing distance from shore (to 100 km); similar trends occurred for the phytoplankton, with several stations having subsurface maxima. Bacterial abundance, thymidine incorporation, and thymidine and glucose turnover rates were all significantly correlated to each other, suggesting they are comparable as relative measures of bacterial activity. Thymidine incorporation per cell, an indicator of specific growth rate, was not correlated to bacterial abundance, suggesting density independent specific growth rates. Bacterioplankton growth rate was evidently influenced more by the standing stock of phytoplankton than by the primary production of the phytoplankton. Thus, bacterial growth may possibly be stimulated by leakage of dissolved organic matter not so much from healthy photosynthesizing cells as from phytoplankton being disrupted and incompletely digested during predation by the zooplankton and nekton. 相似文献
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Transformation of nitrogen dioxide into ozone and prediction of ozone concentrations using multiple linear regression techniques 总被引:1,自引:0,他引:1
Nurul Adyani Ghazali Nor Azam Ramli Ahmad Shukri Yahaya Noor Faizah Fitri MD Yusof Nurulilyana Sansuddin Wesam Ahmed Al Madhoun 《Environmental monitoring and assessment》2010,165(1-4):475-489
Analysis and forecasting of air quality parameters are important topics of atmospheric and environmental research today due to the health impact caused by air pollution. This study examines transformation of nitrogen dioxide (NO2) into ozone (O3) at urban environment using time series plot. Data on the concentration of environmental pollutants and meteorological variables were employed to predict the concentration of O3 in the atmosphere. Possibility of employing multiple linear regression models as a tool for prediction of O3 concentration was tested. Results indicated that the presence of NO2 and sunshine influence the concentration of O3 in Malaysia. The influence of the previous hour ozone on the next hour concentrations was also demonstrated. 相似文献
29.
Dadras Chomachayi Masoud Jalali-arani Azam Martínez Urreaga Joaquín 《Journal of Polymers and the Environment》2021,29(8):2585-2597
Journal of Polymers and the Environment - In this research, the effect of reprocessing on the properties of poly(lactic acid)/poly(ε-caprolactone) (PLA/PCL) blends reinforced with silk... 相似文献
30.
Khan Muhammad Azam Ozturk Ilhan 《Environmental science and pollution research international》2020,27(7):7244-7255
Environmental Science and Pollution Research - This study investigated the causal linkage between environmental pollution by carbon dioxide (CO2) emissions and net foreign direct investment (FDI),... 相似文献