Trends in marijuana and other illicit drug use among college students: results from 4 Harvard School of Public Health College Alcohol Study surveys: 1993-2001

The authors examined changes in college students' illicit drug use, patterns of polydrug use, and the relationship between students' ages of initiation of substance use and later use of marijuana and other illicit drugs between 1993 and 2001. Data from 119 US colleges and universities in the Harvard School of Public Health College Alcohol Study were used in the study. They found significant increases in percentages of students' use of marijuana in the past 30 days (from 13% to 17%), past year (from 23% to 30%), and lifetime (from 41% to 47%) between 1993 and 2001, with most of the increase occurring between 1993 and 1997. Past 30-day use of other illicit drugs increased from 4% to 7% and past year use increased from 11% to 14%. More than 98% of marijuana and other illicit drug users used another substance. They also either smoked, were binge drinkers, and/or were users of another illicit drug. Drug prevention programs should emphasize heavy alcohol use and smoking and should start when students are in high school or earlier.     

Meeting summary--cell biology of Parkinson's disease and related neurodegenerative disorders

Parkinsonian disorders (idiopathic Parkinson's disease and clinically similar disorders) are characterized by impaired movements caused by the degeneration of brain centers involved in regulating normal and smooth movements of the body and its extremities. The mechanisms that cause such degeneration are unknown. This Perspective summarizes research described at a meeting held in June 2003, which was organized by the National Institute of Neurological Disorders and Stroke and the National Institute on Aging to provide an update on recent advances in the cell biology of parkinsonian disorders.     

The Gambling Self-Efficacy Questionnaire: An Initial Psychometric Evaluation

Instruments to assess individuals' self-efficacy for the control of addictive behaviors have been useful for monitoring behavior change, predicting maintenance of treatment gains, and identifying potential relapse situations. The Gambling Self-Efficacy Questionnaire (GSEQ) was developed to assess perceived self-efficacy to control gambling behavior. A demographically diverse sample of 309 adult gamblers completed an initial set of 42 items, of which 16 were selected to form the final version of the GSEQ. The GSEQ showed high internal consistency ( = .96) and good test-retest reliability (r = .86). A factor analysis provided some support for a unitary factor structure. As expected, GSEQ scores were negatively correlated with reports of problematic gambling behavior. Participants experiencing problems related to their gambling behavior scored significantly lower on the GSEQ than those who were not experiencing gambling problems. This psychometric examination of the GSEQ supported its potential utility for treatment planning and outcome evaluation with problem gamblers.     

Product planning—we're still getting it upside down

This paper questions why with all the traditional inventive genius of the British people, this country is failing to hold its own against foreign competition. While the reasons for this are many, the author suggests that the conventional approach to new product development is a major factor. Industry should put the demands of the consumer first rather than an abstract pursuit of technological development. He suggests that for industry in general the needs of consumers should take precedence over the ‘technology push’.     

Pitfalls in planning for multinational operations

This paper reviews the planning practices in multinational firms, focusing particularly on the relationship between subsidiaries and head offices during the planning process. It examines the planning problems experienced by multinationals using a simple paradigm to classify problems according to whether their origin was primarily with home office or with subsidiary; with the planning system itself or with the managers involved in running that system.     

Quantile plots for mean effects in the presence of variance effects for 2k-p designs

In robust parameter design, variance effects and mean effects in a factorial experiment are modelled simultaneously. If variance effects are present in a model, correlations are induced among the naive estimators of the mean effects. A simple normal quantile plot of the mean effects may be misleading because the mean effects are no longer iid under the null hypothesis that they are zero. Adjusted quantiles are computed for the case when one variance effect is significant and examples of 8-run and 16-run fractional factorial designs are examined in detail. We find that the usual normal quantiles are similar to adjusted quantiles for all but the largest and smallest ordered effects for which they are conservative. Graphically, the qualitative difference between the two sets of quantiles is negligible (even in the presence of large variance effects) and we conclude that normal probability plots are robust in the presence of variance effects.     

Estimating the Structure of Agricultural Investment: A Stochastic- Coefficients Approach

Two approaches, a flexibie-accelerator model and a stochastic-coefficients alternative, are used to estimate the structure of aggregate agricultural investment. Structural estimates of the adjustment rates for each model differ. The stochastic-coefficients model, however, performs better in out-of-sample forecasting.     

The True Cost-of-Living Index With Changing Preferences

This article investigates the theoretical and empirical properties of a true cost-of-living index under conditions of changing preferences. A family of true indexes is defined based on the notion of the current utility function. A particular index, based on the previous period's utility level, is then defined. Given this definition, a true cost-of-living index is computed based on a quadratic expenditure system estimated with quarterly data from 1960–1981. For empirical purposes, changes in preferences are represented by the linear habit formation hypothesis. This index is then compared with Paasche and Laspeyres indexes. The true cost-of-living index grows somewhat faster than either the Paasche or Laspeyres index. It also displays considerably more variability.     

Use of a conceptual model of societal drivers of ecological change in South Florida: Implications of an ecosystem management scenario

Human-dominated ecosystems such as in South Florida's Everglades region are greatly affected by societal actions and choices, and efforts to restore degraded ecosystems must take into account the societal drivers of ecosystem change. A conceptual model of societal-ecological interactions within the region illustrates connections between major societal drivers, such as water management and land use, and ecological stressors, such as loss of habitat and nutrient loading. Using the conceptual model as an initial guide for discussion, examination of a restoration scenario for the region shows that social and economic effects from activities proposed in a restoration scenario will likely affect most sectors of South Florida. Political effects from changing land and water management practices likely will be significant, as will the physical effects of changing water structures and management practices. Conceptual models such as this can aid in the initial stages of ecosystem restoration discussions and can assist in planning for subsequent social science evaluations of specific societal impacts of actual proposed governmental restoration alternatives. In crafting restoration scenarios, local, regional, and national decision makers can use conceptual models such as this to help broaden the early considerations of how possible future changes in societal drivers, including management choices, will change ecological stressors that affect ecosystem health.     

Deviations From Desired Age at Marriage: Mental Health Differences Across Marital Status

Although several factors condition mental health differences between married and never‐married adults, given recent increases in marriage delay and permanent singlehood, one modifying factor—deviation from desired age at marriage—has yet to be examined. Using data from the National Longitudinal Survey of Youth 1979 (N = 7,277), the author tested whether deviation from desired age at marriage shapes the mental health of married and never‐married adults as well as mental health differences between them. The results showed that most respondents failed to meet their initial preference for age at marriage. Marrying both earlier and later than desired (compared to on time) resulted in poorer mental health and fewer benefits compared to never marrying. For the never‐married, mental health was best, and differences compared to the married were nonsignificant, for those nearest their desired age at marriage. As timing deviations increased, however, a mental health deficit among the never‐married emerged.