Smoking onset in adolescence: a person-centered analysis with time-varying predictors.

Predictions from smoking-specific versus contextual models of smoking onset were tested with data from a 4-wave sample with 1,364 adolescents. Predictor variables were derived from stress-coping theory, social influence theory, and problem-behavior theory. In addition to groups of abstainers and experimenters, cluster analysis of smoking data indicated 3 groups who showed onset either in 7th grade (early onset), 9th grade (intermediate onset), or 10th grade (late onset). Almost all study variables discriminated the smoking groups from the abstainers. The onset groups were discriminated by Group X Time interactions showing differential changes in predictors (increases in risk factors and declines in protective factors), which occurred just prior to onset. The results generally support a contextual model of the onset process.     

The abstract variable-binding calculus

Theabstract variable binding calculus (VB-calculus) provides a formal frame-work encompassing such diverse variable-binding phenomena as lambda abstraction, Riemann integration, existential and universal quantification (in both classical and nonclassical logic), and various notions of generalized quantification that have been studied in abstract model theory. All axioms of the VB-calculus are in the form of equations, but like the lambda calculus it is not a true equational theory since substitution of terms for variables is restricted. A similar problem with the standard formalism of the first-order predicate logic led to the development of the theory of cylindric and polyadic Boolean algebras. We take the same course here and introduce the variety of polyadic VB-algebras as a pure equational form of the VB-calculus. In one of the main results of the paper we show that every locally finite polyadic VB-algebra of infinite dimension is isomorphic to a functional polyadic VB-algebra that is obtained from a model of the VB-calculus by a natural coordinatization process. This theorem is a generalization of the functional representation theorem for polyadic Boolean algebras given by P. Halmos. As an application of this theorem we present a strong completeness theorem for the VB-calculus. More precisely, we prove that, for every VB-theory T that is obtained by adjoining new equations to the axioms of the VB-calculus, there exists a model D such that _T s=t iff _D s=t. This result specializes to a completeness theorem for a number of familiar systems that can be formalized as VB-calculi. For example, the lambda calculus, the classical first-order predicate calculus, the theory of the generalized quantifierexists uncountably many and a fragment of Riemann integration.The work of the first author was supported in part by National Science Foundation Grant #DMS 8805870.     

Counsellor and client perceptions of the effectiveness of time-limited counselling in an occupational counselling scheme

Counsellors providing brief counselling (6 sessions) in a British Social Services Department completed post intervention questionnaires for 429 clients. These provided information on several measures about the degree to which they felt that their clients had benefitted from the counselling, how far they felt that the number of sessions was adequate, and the nature of the clients' problems. Two hundred and twenty-three of the clients also completed post-intervention questionnaires indicating their degree of satisfaction on a number of measures. There was fair agreement between counsellors and clients that outcomes were satisfactory, and that the number of sessions was adequate, although clients were more satisfied than counsellors. Counsellors identified a range of personal and occupational presenting problems, and around two thirds of problems belonged in the personal domain. Long-tern personal problems received lower satisfaction ratings and were more frequently referred on to other agencies.     

Ethical issues in research on preventing HIV infection among injecting drug users

The ethical issues in conducting research on preventing HIV infection are among the most complex of any area of human subjects research. This article is an update of a 1987 article that addressed potential conflicts between research design and ethics with respect to AIDS prevention among injecting drug users. The present article reviews current ethical issues that arise in the design and conduct of HIV/AIDS prevention research focused on injecting drug users. Disclaimer: The content of this publication is solely the responsibility of the authors and does not necessarily represent the views of the Beth Israel Medical Center or Johns Hopkins University.     

Gender and Hedging: From Sex Differences to Situated Practice

In a reanalysis of women's language, Holmes (1995) has argued that women's use of hedges expresses interpersonal warmth and not, as many researchers have maintained, linguistic tentativeness. It is typically men, she suggests, who employ hedges to convey imprecision and incertitude. In this study, we investigated the use of the hedges sort of and you know in a sample of South African students. Holmes's method of analysis was applied to hedging behavior in 52 dyadic conversations. The study consisted of a 2 (Speaker Gender: Male/Female) × 2 (Audience Gender: Male/Female) × 2 (Condition: Competitive/Noncompetitive) between-subjects experimental design. The results showed that contextual influences eclipsed the effects of gender; in fact, no main effects were found for speaker gender. Fewer hedges were deployed in the competitive condition than in the noncompetitive condition. Moreover, perhaps reflecting differences in social status, both sexes used sort of to express tentativeness more frequently when talking to male addressees. When speaking to female addressees, on the other hand, men deployed facilitative you know hedges more readily than women.     

A group treatment program for bulimia nervosa

Seventeen female patients diagnosed as exhibiting bulimia nervosa participated in a shortterm group treatment program. A combination of exposure with response prevention, life skills training, and psychodynamic group interaction was provided. Results in pretest vs. posttest scores on a battery of tests demonstrated improved control over eating behavior and lowered anxiety and depression.     

M.T.S.: An adaptable microcomputer-based testing system

An Apple II + computer-based human testing system is described. The system, which was developed using the Pascal language, provides library units of low-level procedures to rapidly access a clock, collect responses, control video output, control a touch-sensitive monitor, and display high-resolution graphics. Built-in hardware and software checks provide a high degree of system reliability. Use of easily altered text files for control of trials within a task and inclusion of and ordering of tasks within a session allows the system to be readily adapted.     

Association learning and visual discrimination

The effect of learned stimulus associations on visual discrimination was measured in four experiments. The stimuli were visual shapes which had been scaled for similarity. Two shapes were selected as discriminanda, and each S was pretested and posttested for discrimination of these briefly presented simultaneous pairs of “same” and “different” shapes. During the training, each discriminandum was paired with another simultaneously presented associated shape on a paired-associate response-learning task. The two associated shapes were very similar, intermediate in similarity, or very dissimilar. There was more improvement in posttest discrimination following training with dissimilar associates. We conclude that learned stimulus associations affect visual discrimination.