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Forecasting performance of December corn and November soybean futures contracts during the previous spring was evaluated using the commonly specified price-level and percent-change models. These models invoke different assumptions regarding stationarity. Using Stein's analytical framework, results for the price-level model suggest avoidable social loss existed in the soybean market since 1973, because November futures provided biased forecasts. Regression R2s for both corn and soybeans declined substantially between 1952–1972 and 1973–1997, suggesting total social loss increased. By contrast, results from the percent-change model suggest only unavoidable social loss existed in the corn and soybean markets, because the futures provided unbiased forecasts. R2 increased for corn but declined for soybeans, suggesting unavoidable social loss declined for corn, but increased for soybeans. The important, conflicting nature of the results from the two models underscores the importance of examining alternative model specifications when evaluating price forecasting performance. © 1999 John Wiley & Sons, Inc. Jrl Fut Mark 19: 604–618, 1999  相似文献   
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Using foreign direct investment as a governance mechanism has a cost side that goes beyond mere production and input costs. The governance costs of foreign operations are often vague and underestimated, and sometimes even ignored by companies entering a foreign market. The effects of these costs have also largely been neglected in former empirical research. This study examines the governance cost effects on foreign subsidiary performance. Using data from a survey of 160 Norwegian multinational companies the study shows that there are significant and negative relationships between bargaining, monitoring, and maladaptation costs and subsidiary performance. Conversely, costs incurred due to bonding activities are positively associated with performance. Overall, this study indicates that governance costs play a significant role in explaining the performance of foreign subsidiaries: close to 40% of the variation in performance can be attributed to such costs. Dealing with such costs is hence of utmost importance for the management of multinational companies.  相似文献   
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We have occasionally encountered patients on nonsteroidal antiinflammatory drugs (NSAIDs) in whom double contrast barium studies revealed persistent flattening and stiffening of the distal greater curvature of the stomach. We therefore performed a study to determine the frequency of this finding in patients with NSAID-related gastropathy. Twenty-one cases of erosive gastritis, gastric ulcers, and/or gastric scarring associated with a known history of NSAID use were reviewed by two radiologists who made a joint decision regarding the presence or absence of greater curvature antral flattening. This finding was seen radiographically in five of the 21 patients (24%). Four of the five patients with antral flattening had associated erosions or ulcers in the gastric antrum. The remaining patient had antral flattening as an isolated finding. Our experience suggests that flattening of the greater curvature of the distal antrum, particularly if associated with erosive gastritis or gastric ulcers, is a useful radiologic sign of NSAID-related gastropathy.  相似文献   
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This article examines how rivalry between an electric utility and nonutility generators (NUGs) affects electricity prices, market structure and welfare. If a utility cannot break even financially when outputs are priced at marginal cost, then the Ramsey optimal price paid by a utility purchasing electricity from a NUG should be below avoided cost, in contrast to the requirements of PURPA. The analysis also compares FDC, Residual and Ramsey prices for a utilitys electricity sales. It illustrates how FDC prices may force a utility to exit relatively competitive business markets, eliminating any benefits of economies of scope from serving both business and residential customers.  相似文献   
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