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A new approach to the problem of scheduling course examinations is presented. In principle, an examination schedule which requires a minimum number of examination periods and satisfies the constraint that no student be required to take two examinations simultaneously can be found in two steps. First, courses which may have their examinations scheduled at the same period are grouped together in all possible ways. Then a minimum number of these groups, such that each course is included at least once, are selected. By removing multiple occurrences of courses and then scheduling each group at a different period a minimal schedule can be obtained. Known algorithms for carrying out these procedures are prohibitively expensive. Approximations to the ideal procedure outlined above are given which yield non minimal but feasible schedules with a very small expenditure of time. Results of experiments using these techniques are given. These are encouraging and indicate that further experimentation would be worthwhile. [ABSTRACT FROM AUTHOR]

Several letters to the editor are presented in response to articles in previous issues including an article on "The Welfare Maze," in the February 8, 1971 issue, another review of the book "Waiting for Godot," by T.E. Kalem in the February 15, 1971 issue, and another article on "Speaking Out in Germany," in the February 15, 1971 issue.

Presents letters to the editor. Discussion on the labor movement; Focuses on the Andover controversy; Discussion on French literature and humor.

A model for the appraisal of glucose metabolism is proposed in which glucose homeostasis is divided into three parts: a rate of glucose dispersion into its volume of distribution, a utilization rate, and a production rate. The interrelationships between these processes are formulated as differential equations and are numerically integrated for typical cases. An attempt is made to find the best numerical values for the parameters from a critical analysis of the literature in which data from man have been used as far as possible. The principal results include the demonstration of the efficacy of mathematical models for the quantitative appraisal of glucose metabolism. Specifically, our model suggests the properties of a metabolite which can serve as a feedback control mechanism for the production of glucose, it shows the need for nonlinear mathematics to represent threshold phenomena, and it pOints to gaps in our understanding of glucose homeostasis. The approach used in this model should be useful in the analysis of the effects of drugs on glucose metabolism as well as in the study of normal glucose homeostasis.

Details recurrence relations evaluating Fresnel and exponential integrals. Comparison between the recurrences and the asymptotic series; Advantages of the recurrences; Derivation of rational approximations from the asymptotic series.