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41.
A model to simulate the costs and returns of an individual dairy cow over 14 years under various assumptions of genetic potential, health status and management was developed especially to evaluate the effects of diseases that reduce production and reproduction efficiency and to evaluate alternative management interventions. Data were collected from the Food Animal Health Resource Management System (FAHRMX), Today's Electronic Planning (TELPLAN), Today's Electric Farm Accounting (TELFARM) databases and secondary sources at Michigan State University. A case study of cystic ovaries was analysed using the model. The results showed that it is more economical to treat cystic ovaries than not to treat, and treatment with Gonadotropin Releasing Hormone (GNRH) was superior to Human Chrionic Gonadotropin (HCG). Four to five lactations were the optimum for keeping a dairy cow to replacement and it was estimated that there is a loss of US$0.45 per day of extended calving interval (days open beyond the optimal 70 days).  相似文献   
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Estimation in the interval censoring model is considered. A class of smooth functionals is introduced, of which the mean is an example. The asymptotic information lower bound for such functionals can be represented as an inner product of two functions. In case 1, i.e. one observation time per unobservable event time, both functions can be given explicitly. We mainly consider case 2, with two observation times for each unobservable event time, in the situation that the observation times can not become arbitrarily close to each other. For case 2, one of the functions in the inner product can only be given implicitly as solution to a Fredholm integral equation. We study properties of this solution and, in a sequel to this paper, prove that the nonparametric maximum likelihood estimator of the functional asymptotically reaches the information lower bound.  相似文献   
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An extensive collection of continuous-time models of the short-term interest rate is evaluated over data sets that have appeared previously in the literature. The analysis, which uses the simulated maximum likelihood procedure proposed by Durham and Gallant (2002), provides new insights regarding several previously unresolved questions. For single factor models, I find that the volatility, not the drift, is the critical component in model specification. Allowing for additional flexibility beyond a constant term in the drift provides negligible benefit. While constant drift would appear to imply that the short rate is nonstationary, in fact, stationarity is volatility-induced. The simple constant elasticity of volatility model fits weekly observations of the three-month Treasury bill rate remarkably well but is easily rejected when compared with more flexible volatility specifications over daily data. The methodology of Durham and Gallant can also be used to estimate stochastic volatility models. While adding the latent volatility component provides a large improvement in the likelihood for the physical process, it does little to improve bond-pricing performance.  相似文献   
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In Western Europe in the last two decades the unemployment rate has increased during cyclical downturns only to persist at or around the higher level in the following phase of economic recovery. One of the most notable exceptions to this pattern of unemployment persistence, often termed hysteresis, is the United States. The following article examines the empirical evidence and the possible theoretical explanations for this difference.  相似文献   
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While it is common to observe that our society and world are becoming increasingly complex and fast paced, most of our theories provide no bases upon which to develop appropriate strategies. The need for developing holistic strategies is becoming urgent in two related areas: major interactive technologies and morality. Jonathan King is Associate Professor of Management at the College of Business at Oregon State University. He received his B.A. in philosophy from Antioch College (1965) and his M.B.A. in Finance (1975) and Ph.D. in Business, Government and Society (1980) from the University of Washington. His primary research interests are in the areas of moral philosophy and General Systems Theory. His most important publications are The Three Faces of Thinking, Journal of Higher Education (1986) and Prisoner's Paradoxes, Journal of Business Ethics (1988).  相似文献   
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Condemnation of the long-and-short-haul discrimination has been nearly ubiquitous in the literature on economic theory and transportation. However, the French economist Dupuit developed a case against all transport regulation by relating it to a defense of the practice of place discrimination before the middle of the nineteenth century. He did so, moreover, within an early elaboration of a full price explanation of competitive functioning. This paper analyzes the idea in Dupuit's context and argues that this so-called form of price discrimination is actually an efficient and necessary form of the competitive process.  相似文献   
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