Chartering strategies for shipping companies

This paper describes a model which may be used in the evaluation of the relative effectiveness of policies used in the areas of ship chartering and the switching of combined carriers between the dry cargo market and the tanker market. The policies for chartering and market switching are expressed in the form of ‘desired proportions’ of the fleet operating in a particular charter-mode or a particular market. Graphical illustration of this form of expression of policies can be easily understood, so that alternative policies can be designed with relative ease. The effectiveness of a particular form of policy under various freight market conditions can be determined from the model, the use of which is illustrated by its application to the deployment of the fleet of an hypothetical shipping company. It is assumed that the feedback connection between the company's actions and the marketplace is negligible.     

Pregnant women's attitudes toward the abortion of defective fetuses

A survey asked 190 pregnant women their opinions on whether a hypothetical other woman would be justified in having an abortion under ten different circumstances, four of which related to abnormalities of the fetus. They were then asked whether they would be justified in having an abortion under these same circumstances. Also assessed were these women's views concerning the justifiability of abortion for a specific group of fetal abnormalities, neural tube defects. Respondents were more likely to view abortion as justifiable for a hypothetical other than for themselves. However, there was no evidence that pregnant women's views about abortion are more conservative than those of the general public. The majority of respondents considered abortion of a defective fetus to be justified, both for themselves and for others. The best predictor of abortion attitudes was respondent's views about the ideal number of children in a completed family.This research was supported by a grant from Maternal and Child Health Research, Bureau of Community Health Services, DHHS. Reprint requests should be sent to Dr. Ruth Faden at the Johns Hopkins University School of Hygiene and Public Health, Division of Health Education, 615 N. Wolfe Street, Baltimore, MD 21205.     

Exchange curves for fixing batch quantities

The problem considered is that of choosing batch quantities to minimize costs, subject to the constraints that neither overall set-up costs nor overall set-up time can be increased beyond certain limits. Theoretical and graphical solutions are obtained for two possible formulations of the problem, and a simple practical procedure is suggested.