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21.
A very useful experiment of two dimensional potential mapping, namely electrolytic tank model, for graduate and post graduate level physics students is given here. Laplace's equation is solved for the above and the results are compared with the experiment. The agreement is so good that this is extended to complex problems. Monte Carlo simulation, an alternative to the above experiment, is developed for these complex problems and compared with the experimental results of electrolytic tank model.  相似文献   
22.
Glutathione-5-transferase (GST) and glutathione (GSH) levels were estimated in the lungs of 3 and 30 months old rats. GST activity was found to be significantly reduced in the old rats (30 months age) compared to the young rats (3 months age). In old rats, with methionine supplementation GST activity was increased whereas with vitamin C supplementation GSH levels were increased. The data show that the supplementation of methionine as well as of vitamin C have beneficial effect on the scavenging system and protect lungs against the free radical damage during ageing.  相似文献   
23.
Vegetables are important constituents of the human diet. Heavy metals and nitrate are among the major contaminants of vegetables. Consumption of vegetables and fruits with accumulated heavy metals and nitrate has the potential to damage different body organs leading to unwanted effects. Breeding vegetables with low heavy metal and nitrate contaminants is a cost-effective approach. We investigated 38 water spinach genotypes for low Cd and nitrate co-accumulation. Four genotypes, i.e. JXDY, GZQL, XGDB, and B888, were found to have low co-accumulation of Cd (<0.71 mg/kg dry weight) and nitrate (<3100 mg/kg fresh weight) in the edible parts when grown in soils with moderate contamination of both Cd (1.10 mg/kg) and nitrate (235.2 mg/kg). These genotypes should be appropriate with minimized risk to humans who consume them. The Cd levels in the edible parts of water spinach were positively correlated with the concentration of Pb or Zn, but Cd, Pb, or Zn was negatively correlated with P concentration. These results indicate that these three heavy metals may be absorbed into the plant in similar proportions or in combination, minimizing the influx to aerial parts. Increasing P fertilizer application rates appears to prevent heavy metal and nitrate translocation to shoot tissues and the edible parts of water spinach on co-contaminated soils.  相似文献   
24.
Conceptual change in undergraduate capstone courses provides unique opportunities to examine how students draw from multiple courses and experiences to resolve conceptual confusion. We examined how senior-level natural resource management students revised their conceptions of ‘ecosystem’ throughout their capstone course. The concept of ecosystem is complicated by a lack of shared meaning across disciplines. Our grounded theory study analyzed student coursework and pre/post interviews. It was informed by socio-cultural and conceptual change theories and used an ecological literacy metric to examine how students’ conceptualizations of the relationships between natural, ecosystem, human, and human artifact influenced their conceptions of ecosystems. Students who did not describe ecosystems as natural struggled less with integrating human society into ecosystems than their peers that did. We conclude that it is important to explicitly create shared meaning of key conceptions at the start of a capstone course to facilitate shared meaning-making and desired conceptual change during the course.  相似文献   
25.
The hypocholesterolemic effect of the water extract of the bark ofFicus bengalensis was investigated in 3 groups of rabbits, 5 in each group. Group 1 rabbits served as healthy controls and were fed with groundnut oil 1 ml/kg body wt. (bw) for five weeks. Groups 2 and 3 were made hypercholesterolemic by feeding orally cholesterol suspended in groundnut oil (1 ml/kg bw) at a dose of 100 mg/kg bw/day. Group 2 animals (untreated) continued to get the same amount of cholesterol for another four weeks. Group 3 animals received water extract of the bark (50 mg/kg bw/day) in addition to cholesterol as above. At the end of the 5th week, water extract not only prevented the elevation of serum cholesterol in the treated animals (Group 3) but also brought down its level to 160±14 mg% as compared to untreated animals (Group 2) 290±42 mg%. There was improvement in other parameters of lipid profile namely HDL & LDL+VLDL cholesterol and triacylglycerol.  相似文献   
26.
Plasma vitamin E levels were estimated in 75 patients each of carcinoma breast and benign breast diseases. Mean plasma vitamin E concentration was found to be significantly reduced in malignancy compared to the controls as well as the non malignant conditions. The decrease in plasma vitamin E in cancer patients was directly related with the TNM stage of cancer. The levels, however, did not vary significantly with respect to histopathology or after 8 days of surgery.  相似文献   
27.
A 44-item survey instrument was designed to determine secondary students?? views about how useful various specific actions related to reducing global warming might be, their willingness to undertake these various actions and the extent to which these 2 might be linked. The instrument was administered to students in grades 6??C?10 (n?=?768) from 4 large schools in metropolitan Delhi, India in which the teaching language was English. The findings indicated that this cohort of Indian students exhibited high levels of concern about climate change and strong willingness to act against global warming and in favour of the environment. The findings are tentatively compared with those from 2 similar survey studies conducted in Western contexts (Spain and Australia).  相似文献   
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29.
Modeling Web-based library service quality   总被引:1,自引:0,他引:1  
Studies of e-service quality have consistently used adaptations of service-quality measurement tools that have been adopted and extended from traditional service-quality frameworks. However, a fresh insight into the investigation of key determinants of Web-based library service quality, with an emphasis on how library customers perceive service quality, has much to offer. Key determinants were identified, and contributed to the development and empirical testing of a proposed conceptual model of service quality that encompasses environment, delivery, and outcome quality. Unlike the disconfirmation approach, the performance-only measure was used. Participants included postgraduates and academic staff from four research intensive universities in Malaysia. Exploratory factor analysis and confirmatory factor analysis using structural equation modeling was carried out in order to develop and validate a measurement model for Web-based service quality, which included three second-order dimensions and eight first-order dimensions. Insights into the conceptualization of Web-based library-service quality as a multidimensional hierarchical construct are provided. The emergence of specific determinants specific to the Web services supports the notion that measurement of electronic-service quality is different from traditional services, though they may share some common factors.  相似文献   
30.
Against the background of neuroimaging studies on how the brain processes numbers, there is now converging evidence that numerical magnitude representations are crucial for successful mathematics achievement. One major drawback of this research is that it mainly investigated mathematics performance as measured through general standardized achievement tests. We extended this research by investigating the association between numerical magnitude representations and children's strategy use during single‐digit arithmetic. Our findings reveal that children's symbolic but not nonsymbolic numerical magnitude processing skills are associated with individual differences in arithmetic. Children with better access to magnitude representations from symbolic digits retrieve more facts from their memory and are faster in executing fact retrieval as well as procedural strategies. These associations remain even when intellectual ability, digit naming, and general mathematics achievement are additionally controlled for. All this indicates that particularly the access to numerical meaning from Arabic symbols is key for children's arithmetic strategy development, which suggests that educators and remedial teachers should focus on connecting Arabic symbols to the quantities they represent.  相似文献   
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