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151.
The aim of this study was to evaluate the use of total coliforms (TC) and faecal coliforms (FC) using a membrane filtration method for precise monitoring of faecal pollution in Korean surface water. The samples were collected in Korea from both main rivers and their tributaries. Presumptive TC * FC were enumerated. The ratios of presumptive FC to TC were not constant, but varied widely, and TC were difficult to enumerate because of overgrowth by background colonies. For FC this was not the case. Seven hundred and three purified strains of presumptive TC * FC and their background colonies were biotyped using API 20E. Among 272 presumptive TC, non-faecal related species, Aeromonas hydrophila dominated (34.6%) and E. coli accounted for only 5.1%. In contrast, E. coli made up 89% of the 209 presumptive FC. Furthermore, of 164 background colonies on Endo Agar LES, 54.9% was A. hydrophila, while background colonies on m-FC Agar were few (58 strains), and despite their atypical colony appearance, most of them were biotyped as enteric bacteria. These results reveal that the detection of FC rather than TC using m-FC Agar is more appropriate for faecal pollution monitoring in eutrophicated surface water located in a temperate region.  相似文献   
152.
Previous work shows that establishments with higher proportions of women are more likely to use piece rates but that individual women are less likely to receive performance pay. We present a model in which lower expected tenure and labor force attachment are positively associated with piece rates but are negatively associated with other forms of performance pay. Analysis of the National Longitudinal Survey of Youth (NLSY) confirms that women are more likely to be paid piece rates and simultaneously less likely to be paid commissions and bonuses.  相似文献   
153.
As educators in the field of risk management and insurance, we see know- ledge of risk management and insurance as a core business function. However, some colleagues and students see insurance as cold-call sales or companies with a lot of money that continue to raise their prices. So we have to find ways to make our public aware of the usefulness of risk management and insurance in the business world and in private life and of the opportunities that having such knowledge presents to all business majors and business people. One method that is beginning to show dramatic improvements in at least our students' perceptions of the field and the major involves industry-sponsored game nights. While not an academic endeavor nor strictly risk management education, we believe the idea provides a useful tool for opening students' eyes to the need for knowledge of risk management and insurance and of the opportunities that are available in the insurance industry and its related fields. This article discusses the history of such an event at Appalachian State Univer- sity, the current status of the North Carolina Surplus Lines Association (NCSLA) event, and the benefits of the event.  相似文献   
154.
The Local Whittle Estimator of Long-Memory Stochastic Volatility   总被引:1,自引:0,他引:1  
We propose a new semiparametric estimator of the degree of persistencein volatility for long memory stochastic volatility (LMSV) models.The estimator uses the periodogram of the log squared returnsin a local Whittle criterion which explicitly accounts for thenoise term in the LMSV model. Finite-sample and asymptotic standarderrors for the estimator are provided. An extensive simulationstudy reveals that the local Whittle estimator is much lessbiased and that the finite-sample standard errors yield moreaccurate confidence intervals than the widely-used GPH estimator.The estimator is also found to be robust against possible leverageeffects. In an empirical analysis of the daily Deutsche Mark/USDollar exchange rate, the new estimator indicates stronger persistencein volatility than the GPH estimator, provided that a largenumber of frequencies is used.  相似文献   
155.
Using data for a sample of Malaysian stocks that are traded in both Malaysia and Singapore, we show that the turnover rate (trading volume relative to shares held) is significantly higher in the foreign market than in the domestic market. We also find that ownership of cross–listed shares by foreign investors is not motivated by diversification benefits. Instead, we find that the proportion of a firm's shares held in Singapore is directly related to the firm's level of systematic risk.  相似文献   
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This article focuses on the housing issues of rural migrants arising from urbanization, with particular reference to chengzhongcun, a topic with considerable impact on policymaking. An attempt is made to understand the underlying rationale of self‐help in housing and the important role of chengzhongcun in sheltering rural migrants in the context of China's rural‐urban dichotomy. As demonstrated in this study, chengzhongcun accommodate, with little in the way of government resources and assistance, millions of rural migrants because of their social accessibility and affordability. While not denying their social problems, we argue that chengzhongcun in fact act as an innovative and positive agent to promote urbanization in present day China by housing massive numbers of rural migrants and assimilating them into cities. Current government policies towards chengzhongcun have generated a wide range of interest conflicts and confrontations. The consequences of such conflicts show that the government policies were problematic and unworkable, as they violated basic market principles as well as citizen rights. Policy strategy towards the redevelopment of chengzhongcun must acknowledge their credibility in the Chinese road to urbanization and requires more thoughtful and prudent consideration of migrants' demands for affordable housing.  相似文献   
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The planimetric shifts in channel location of large alluvial rivers are a critical component in the creation of diverse structures and functions in riverine habitats. Engineered management schemes must also compensate for this type of channel change to protect resources and maintain navigation channels. The stability of the Lower Mississippi River channel was assessed through an analysis of historical records of channel position produced and archived by the United States Army Corps of Engineers. Channel location was recorded for the years 1765, 1820, 1881, 1915, 1930, 1937, 1960 and 1970. Channel stability was measured by two introduced metrics on a cell‐by‐cell basis: (1) the standard deviation of Euclidean distance to a channel cell for the entire period of record, and (2) the rate of Euclidean distance change between years in the period of record. At a coarse spatial scale, channel instability increased in the downstream direction. The variability of channel stability also increased in the downstream direction. Analysis of this variability identified alternating areas of high and low stability occurring with greater frequency as distance downstream increased. These findings are validated by past studies of channel stability along the Lower Mississippi River. As a result, the proposed metrics provide a consistent, quantitative, efficient and cost‐effective means of identifying areas of channel instability at several spatial scales. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
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