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.     

Autism: understanding conceptual processing deficits

Autism is a behavioral diagnosis characterized by a triad of impairment, which includes impaired communication, impaired social skills, and impaired spontaneity. The outward behavior exhibited by people with autism represents a different cognitive processing style than that seen in typical development. Understanding the way people with autism process and store information is important for intervention. The majority of people diagnosed with autism do not have symptoms of mental retardation and need access to mainstream services to work on the problems presented by daily life.     

Development and validation of the College Tobacco Survey

The authors report on the development and assessment of an instrument to measure baseline campus cigarette use and outcomes from prevention programs, including those using a social norms approach combined with environmental policy change. They administered the 37-item College Tobacco Survey (CTS) to a convenience sample of 1,279 college students in freshmen-level classes at a large urban university. Factor analysis of 15 belief items revealed 3 factors: Peer Environment, Personal Effects, and Campus Policy Endorsement. The findings support the survey's reliability and validity. The authors discuss potential uses of the survey in terms of social norms and environmental prevention programs.     

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.     

Misperceptions of the norms for the frequency of alcohol and other drug use on college campuses.

Data from surveys of students representing 100 diverse college campuses were used to investigate the difference between the self-reported frequency of a drug's use and students' perceptions of the frequency of use. Students were asked about the frequency of their own use of 11 drugs (alcohol, tobacco, marijuana, cocaine, amphetamines, sedatives, hallucinogens, opiates, inhalants, designer drugs, and steroids) and how often they thought "the average student" on their campus used these drugs. Respondents typically misperceived their peer norms (designated as the median of self-reported use) by substantially overestimating how often the average student used each drug, both in campus samples where abstinence or infrequent use were the median of self-reports and in samples where the median of self-reports revealed more frequent use. To the extent that they may promote or reinforce students' actual use, these misperceptions should be considered in designing college drug prevention programs.