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排序方式: 共有114条查询结果,搜索用时 9 毫秒
1.
Construction of the La Grande Complex in Eastern Canada called for complete or partial diversion of six rivers, the mean annual discharge of which varied from 60 to 1600 m3 s?1, and the transfer of water from two adjoining watersheds (1586m3 s?1) into La Grande Rivière. Three of these rivers with reduced flow, Eastmain (from 700 to 95m3 s?1), Opinaca (from 260 to 35m3 s?1), and Caniapiscau (from 1708 to 960m3 s?1) and the waterways with increased flows, Boyd-Sakami (from 1 to 811m3 s?1) and La Grande Rivière (from 1760 to 3400m3 s?1) were intensively monitored from 1978 to 1988, while the others were surveyed sporadically. Very few modifications were observed, compared to previous conditions, in banks stability, water quality, and aquatic fauna of the affected rivers: those which appeared can be explained by the water level fluctuations, the water quality of the tributaries of the residual drainage basin, and/or by the direct influence of the reservoirs. In James Bay, the areal extent of the Eastmain River and La Grand Rivière plumes varied with discharge in an exponential relation, mostly under ice cover; resources from the coastal environment had not yet undergone any major changes. Because of the very small population dwelling in the area, less than 3000 inhabitants, modifications in the hydrological regime of these rivers did cause relatively few impacts, the main being greater banks instability in specific locations, reduction of the thickness and ice cover on La Grande Rivière, enhancement of navigation constraints on Eastmain River, and higher mercury levels in fish related to operation of the reservoirs. 相似文献
2.
Bonenfant D Bourgeois FR Mimeault M Monette F Niquette P Hausler R 《Water science and technology》2011,63(12):2827-2832
Carboxymethylcellulose (CMC) and beta-cyclodextrin (beta-CD)-based polymers functionalized with two types of quaternary ammonium compounds (QACs), the alkaquat DMB-451 (N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride) (DMD-451) named polymer DMB-451, and FMB 1210-8 (a blend of 32 w% N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride and 48 w% of didecyldimethylammonium chloride) named polymer FMB 1210-8, were synthethized and characterized by Fourier transform infrared spectroscopy. The antimicrobial activities of these polymers against Eschericia coli were also evaluated at 25 degrees C in wastewater. The results have indicated that the polymer FMB 1210-8 possesses a high-affinity binding with bacterial cells that induces a rapid disinfection process. Moreover, in the same experimental conditions of disinfection (mixture of 1.0 g of polymer and 100 mL of wastewater), the polymer FMB 1210-8 has a higher antimicrobial efficiency (99.90%) than polymer DMB-451 (92.8%). This phenomenon might be associated to a stronger interaction with bacterial cells due to stronger binding affinity for E. coli cells and greater killing efficiency of the C10 alkyl chains QAC of polymer FMB 1210-8 to disrupt the bacterial cell membrane as compared to N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride. Together, these results suggest that the polymer FMB 1210-8 could constitute a good disinfectant against Escherichia coli, which could be advantageously used in wastewater treatments due to the low toxicity of beta-CD and CMC, and moderated toxicity of FMB 1210-8 to human and environment. 相似文献
3.
Who produces for whom in the world economy? 总被引:2,自引:0,他引:2
Guillaume Daudin Christine Rifflart Danielle Schweisguth 《The Canadian journal of economics》2011,44(4):1403-1437
Abstract For two decades, the share of trade in inputs, also called vertical trade, has been dramatically increasing. In reallocating trade flows to their original input‐producing industries and countries, this paper suggests a new measure of international trade: ‘value‐added trade’ and makes it possible to answer the question ‘who produces for whom?’ In 2004, 27% of international trade was vertical trade. The industrial and geographic patterns of value‐added trade are very different from those of standard trade. Value‐added trade is relatively less important in regional trade but the difference is not more important for Asia than for America. 相似文献
4.
Issues which Impact upon Marketing in the Small Firm 总被引:1,自引:1,他引:0
Defining the small firm is somewhat arbitrary as criteria used to classify entities as such include size, number of employees, sales volume, asset size, type of customer, capital requirements and market share. There is, however, general agreement that smallness and newness create specific difficulties for business. Furthermore, there is widespread acceptance of the notion that small firms typically possess certain characteristics, which serve to differentiate them from larger organisations. These characteristics include inherent weaknesses with respect to capitalisation and marketing awareness and practice. Small firms are perceived as vulnerable yet valuable entities, important both economically and socially. High failure rates of small firms are largely attributed to weaknesses in financial management and marketing. Many classical management concepts are unsuitable for application in a small firm context, with research suggesting non-implementation of theoretically based marketing practice is the rule rather than the exception in the small firm. This paper reviews issues pertaining to marketing practice in the small firm. It examines the absence of agreed definitions of "the small firm" and "success" or "failure" of such entities, offers definitions for these terms, acknowledges the importance of small firms to the economy, reviews small firm characteristics, acknowledges inherent weaknesses with regard to finance and marketing in small firms, reviews marketing practice in the context of small firm characteristics, and considers the roles of marketing educators and owner/managers in improving small firm's marketing practice. 相似文献
5.
Xiang Bi Zhifeng Gao Lisa A. House Danielle S. Hausmann 《International Journal of Consumer Studies》2015,39(2):162-171
Researchers have investigated the role of sensory attributes and organic labels on consumers’ preferences and perceptions of food, but few has examined whether sensory attributes are relevant for consumers who prefer organic food and the extent to which sensory attributes influence consumer's marginal willingness to pay for organic food. The objective of this study is to determine how sensory attributes and organic label work together to influence consumer's stated preference and marginal willingness to pay for orange juice. To achieve this, we conducted a blind sensory evaluation of two orange juices followed by a discrete choice experiment to determine the extent to which consumer's stated preference for orange juice labelled as organic is affected by sensory experience preceding the choice experiment. Random parameter logit models and latent class conditional logit models are used to explain stated preference. Results indicate that the effect of sensory attributes on consumer's marginal willingness to pay differed by organic juice and conventional juice. 相似文献
6.
This study tests the validity of using the CAPM beta as a risk control in cross‐sectional accounting and finance research. We recognize that high‐risk stocks should experience either very good or very bad returns more frequently compared to low‐risk stocks, that is, high‐risk stocks should cluster in the tails of the cross‐sectional return distribution. Building on this intuition, we test the risk interpretation of the CAPM's beta by examining if high‐beta stocks are more likely than low‐beta stocks to experience either very high or very low returns. Our empirical results indicate that beta is a strong predictor of large positive and large negative returns, which confirms that beta is a valid empirical risk measure and that researchers should use beta as a risk control in empirical tests. Further, we show that because the relation between beta and returns is U‐shaped, that is, high betas predict both very high and very low returns, linear cross‐sectional regression models, for example, Fama–MacBeth regressions, will fail on average to reject the null hypothesis that beta does not capture risk. This result explains why previous studies find no significant cross‐sectional relation between beta and returns. 相似文献
7.
Recent empirical evidence reveals considerable divergence between management reports and employee reports regarding organizational high performance work practices (HPWPs). This divergence implies that employees may not participate in some HPWPs that are formally present in their organizations, but also, that employees may participate in HPWPs that are not formally present in their organizations. In this study, we examine the implication of the latter case (i.e., employee participation in “informal” HPWPs) for employee‐level and organization‐level outcomes. Our analyses, using data from the Statistics Canada Workplace and Employee Survey, suggest that employee participation in informal HPWPs is associated with enhanced job satisfaction and workplace profitability in a similar way as employee participation in formal HPWPs is associated with these outcomes. 相似文献
8.
Lewis Danielle Springer Thomas M. Anderson Randy I. 《The Journal of Real Estate Finance and Economics》2003,26(1):65-80
Using a stochastic frontier methodology that incorporates Bayesian statistics, this paper analyzes the cost efficiency of real estate investment trusts (REITs) by observing the deviations of the measured costs of individual REITs from a defined efficient cost frontier. Using 1995–1997 data, we extend the previous research in this area and measure REIT efficiency more precisely by isolating random measurement error from the overall deviations from the efficient cost frontier. We calculate the magnitude of each REIT's managerial inefficiency, the industry inefficiency, and returns to scale. In addition, we assess specific characteristics of REITs for their contribution to inefficiency by calculating the odds ratio that a REIT with a specific characteristic is more efficient than a REIT with an alternative characteristic. The results show that, for the years studied, REITs are relatively cost efficient with most REITs facing increasing returns to scale. Additionally, the REIT's use of debt and the REIT's management style significantly affect the cost performance of REITs during the aforementioned time period. Finally, diversification across property types, as measured, does not seem to influence REIT cost efficiency. 相似文献
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