Optimal scaling of Metropolis algorithms: Heading toward general target distributions

The authors provide an overview of optimal scaling results for the Metropolis algorithm with Gaussian proposal distribution. They address in more depth the case of high‐dimensional target distributions formed of independent, but not identically distributed components. They attempt to give an intuitive explanation as to why the well‐known optimal acceptance rate of 0.234 is not always suitable. They show how to find the asymptotically optimal acceptance rate when needed, and they explain why it is sometimes necessary to turn to inhomogeneous proposal distributions. Their results are illustrated with a simple example.     

Micromomentary movement and the deconding of face and body cues

A new version of the Profile of Nonverbal Sensitivity Test (PONS)—a standardized test of sensitivity to nonverbal cues—was developed to determine the effects of five levels or sequences of micromomentary movement on accuracy in decoding nonverbal face and body cues, presented for 125 microseconds (msecs). The five sequences were: backward movement, partially backward movement, no movement, partially forward movement, and fully forward movement. Two versions of this test—the Test of Micromomentary Movement Effects (TOMME)—were administered to two samples of female high school and college students. The results, averaged over face and body cues, showed that as the movement sequences more closely approximated the fully forward sequence, decoding accuracy increased. These results, showing the benefits of adding properly sequenced information at split second (42 msec) exposures, not only support the findings of previous researchers that micromomentary facial affect displays may be helpful in decoding nonverbal facial cues, but also suggest that micromomentary movements may be important for decoding body cues as well.     

Concepts,Theory, and Techniques PRINCIPLES OF MULTIOBJECTIVE OPTIMIZATION*

This paper attempts to isolate and analyze the principal ideas of multiobjective optimization. We do this without casting aspersions on single-objective optimization or championing any one multiobjective technique. We examine each fundamental idea for strengths and weaknesses and subject two—efficiency and utility—to extended consideration. Some general recommendations are made in light of this analysis. Besides the simple advice to retain single-objective optimization as a possible approach, we suggest that three broad classes of multiobjective techniques are very promising in terms of reliably, and believably, achieving a most preferred solution. These are: (1) partial generation of the efficient set, a rubric we use to unify a wide spectrum of both interactive and analytic methods; (2) explicit utility maximization, a much-overlooked approach combining multiattribute decision theory and mathematical programming; and (3) interactive implicit utility maximization, the popular class of methods introduced by Geoffrion, Dyer, and Feinberg [24] and extended significantly by others.     

Vendor Selection with Bundling*

Product bundling has become increasingly prevalent not only in consumer goods but also in the industrial sector. We study a purchasing problem in which a buyer must obtain necessary numbers of various stock items from a variety of vendors who charge different prices, have limited capacities and different levels of quality, and offer bundled products at discounted prices. We examine relationships among different bundling scenarios and show that the most general scenario is one in which free items are given to the buyer when sufficient quantities are purchased. We develop a mixed integer linear program that finds the purchasing strategy for the buyer that minimizes the total purchase cost. We present computational results which indicate that the problem is very tractable to solve optimally on a personal computer with standard optimization software. Finally, three extensions of the model are discussed.     

Ethnic Group Differences in Adolescents' Responses to AIDS

Adolescents of Anglo-Celtic, Greek, Italian and Chinese descent attending a wide range of post-secondary institutions in Victoria (mean age = 18 years) were asked about their sexual behaviours, knowledge about AIDS, and social responses to the threat of AIDS. There was evidence of relatively high levels of sexual activity, with some members of all groups engaging in risky sexual behaviour. Anglo-Australians were more sexually active and informed about AIDS, with more equality between the sexes in these respects than the other groups. There was a distinction made between behaviours regarded as safe with regular and casual partners, but the meaning attributed to regular partnership differed. Greek- and Italian-Australian young men endorsed monogamy for their regular partners but not necessarily for themselves, and Anglo-Australians accepted a relationship of shorter duration as regular. Greater knowledge was not related to safer sexual behaviour, but discussion about a regular partner's previous sexual history correlated with more risky sexual behaviour. Overall, risk levels were not high but the casual-regular partner distinction, together with the greater use of relatively unrealistic strategies for dealing with AIDS in association with risky behaviour in the non-Anglo groups, gives cause for concern.     

Discount rates and risky sexual behaviors among teenagers and young adults

This article examines the relationship between personal discount rates and sexual behaviors in a sample of teenagers and young adults. We find that higher discount rates (an indication of less willingness to forego current consumption for future consumption) are significantly associated with a range of sexual behaviors, including ever having sex, having sex before age 16 years, and past or current pregnancy. These associations are consistent with previous studies showing a link between discounting and other, non-sexual health behaviors. JEL Classification D80 · D90 · I10     

Pathological gambling: A review of the literature (prepared for the American Psychiatric Association task force on DSM-IV committee on disorders of impulse control not elsewhere classified)

This is a review of the literature on pathological gambling prepared for the work group on disorders of impulse control, not elsewhere classified of the American Psychiatric Association. It introduces the new DSM-IV criteria as well as outlines the phases of the career of the pathological gambler. Research discussed includes that on pathological gambling and psychiatric disorders, substance abuse, family issues, children, finances, and crime. Psychoanalytic, personality, behavioral, sociological, psychologically based addiction theories, and physiological research are also summarized. Finally, treatment outcome studies are outlined.This article is dedicated to the memory of Robert L. Custer, MD whose inspiration and encouragement stimulated much of the research discussed herein.