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81.
An aggregate analysis of supply response in the paddy (rice) sector of Sri Lanka during 1952-87 is conducted to identify the impact of pricing policy, irrigation programmes, institutional credit and concessional sales on area, yield and overall supply. The focus of the estimation procedure is the selection of an appropriate functional form for regressions and on the price variable that best represents the price to which producers respond in making area and yield decisions. In the case of both area and yield, the econometric criteria favour the acceptance of log-linear equations with the ratio of the guaranteed price of paddy to fertiliser price. On the basis of overall supply elasticity estimates, it is concluded that while pricing policy, irrigation programmes and institutional credit provide incentives to the expansion of paddy production, concessional sales of rice act as a disincentive. 相似文献
82.
In this paper we investigate the use of the structured full rank model for hedging the balance sheet of a financial institution. Simulation results suggest that the optimal hedge is insensitive to changes in parameter estimates. In addition, we hedge a portfolio of Treasury bills using both the full information covariance matrix and the structured covariance matrix. We then contrast these results with those obtained from a duration-based model. Empirical results suggest that the structured full rank model is generally more effective in hedging applications than either the full information model or duration-based model. 相似文献
83.
Mark D. Karper Clifford B. Donn Marie E. Lyndaker 《Employee Responsibilities and Rights Journal》1994,7(3):219-233
The maritime industry provides an interesting case study of the design and implementation of drug-testing programs in the
transportation industry during the 1980s. It is clear that such programs were designed and implemented less because of empirical
evidence of safety problems than for political reasons. The results in the maritime industry are indicative of a program that
is expensive to operate, intrusive with regard to employee privacy, and which will have little or no impact on safety. Focusing
such programs on the issue of impairment rather than on the issue of drug usage per se is likely to improve the outcome of
the programs.
Although, despite common belief, there is little evidence that drug usage or the “drug problem” in U.S. society as a whole
had gotten worse in the preceding years (Schonsheck, 1989, 250–251). 相似文献
84.
Tracking programs have been criticized on the grounds that they harm disadvantaged children. The bulk of empirical research supports this view, but existing studies compare outcomes across students placed in different tracks. Track placement is likely to be endogenous with respect to student outcomes. We use a new strategy for overcoming the endogeneity of track placement and find no evidence that tracking hurts low-ability children. Previous studies have also been based on the assumption that students' enrollment decisions are unrelated to whether or not the school tracks. When we account for the possibility that tracking programs affect school choice, we find evidence that they may help low-ability children. 相似文献
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Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal
allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully
disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized
allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into
the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and
scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and
scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors
of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available.
Received: August 8, 2000; revised version: January 8, 2001 相似文献
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