Buckling considerations in the design of elevated steel water tanks

Improved fabrication techniques and the availability of higher strength steels have encouraged greater use of thin-walled containment vessels in recent years. A major increase in computing capability to analyse these structures for buckling modes has also occurred and this paper considers two recently constructed steel water towers. In particular, the effect of door cut-outs on buckling capacity is examined. The analysis techniques used in the paper provide powerful tools for readily estimating buckling modes and assessing the effects of various stiffener arrangements. By far the most effective stiffening element in the stem of a water tower is a horizontal diaphragm which maintains a circular cross-section.     

Limit-cycle behaviour in a model chemical reaction: the cubic autocatalator

Limit cycles are sought in a mathematical model of a simple hypothetical chemical reaction involving essentially only two reacting species. Physically, these limit cycles correspond to time-periodic oscillations in the concentrations of the two chemicals. A combination of analytical and numerical methods reveals that limit-cycle behaviour is only possible in a restricted region of the parameter space. Strong numerical evidence is presented to assert that the limit cycle is unique and stable to infinitesimal perturbations. Numerical solutions are displayed and discussed.     

Effects of dopamine transporter and receptor polymorphisms on smoking cessation in a bupropion clinical trial.

This study examined the role of dopaminergic genes in prospective smoking cessation and response to bupropion treatment in a placebo-controlled clinical trial. Smokers of European ancestry (N=418) provided blood samples for genetic analysis and received either bupropion or placebo (10 weeks) plus counseling. Assessments included the dopamine D2 receptor (DRD2) genotype, dopamine transporter (SLC6A3) genotype, demographic factors, and nicotine dependence. Smoking status was verified at the end of treatment (EOT) and at 6-month follow-up. The results provided evidence for a significant DRD2 × SLC6A3 interaction effect on prolonged smoking abstinence and time to relapse at EOT, independent of treatment condition. Such effects were no longer significant at 6-month follow-up, however. These results provide the first evidence from a prospective clinical trial that genes that alter dopamine function may influence smoking cessation and relapse during the treatment phase. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Counselor-client agreement on session impact.

We propose a new framework for understanding studies of counselor–client agreement about their counseling. The framework includes five factors: the scope of counseling being studied (process, impact, or outcome), the dimension (index) being rated (in this study, session Depth, Smoothness, Positivity, or Arousal), the measure used to assess agreement (correlations or absolute differences), the level at which the analysis is conducted (session, client, or counselor), and the type of agreement—(a) consensus, the similarity of counselors' own ratings to clients' own ratings; (b) counselor awareness, the similarity of counselors' perceptions of their clients to clients' own ratings; (c) client awareness, the similarity of counselors' own ratings to clients' perceptions of their counselors; and (d) matched awareness, the similarity of counselors' perceptions of their clients to clients' perceptions of their counselors. In a study of session impact (scope), degree of agreement was found to vary substantially with each of the other factors—type of agreement, dimension rated, measure of agreement, and level of analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dorsal raphe, substantia nigra and locus coeruleus: interconnections with each other and the neostriatum

Using a retrograde axonal transport method, direct projections to the neostriatum were demonstrated from the dorsal raphe nucleus, a large area of the ventral midbrain tegmentum (including the ventral tegmental area of Tsai, the substantia nigra pars compacta, reticulata and suboculomotoria), and the tegmentum ventral to the caudal red nucleus. A direct projection was also found from the mediodorsal part of the substantia nigra to the rostral part of the dorsal raphe nucleus. Projections from the entopeduncular nucleus (pallidum) and the lateral hypothalamic area to the lateral habenular nucleus, and from the latter to the dorsal raphe nucleus were also found. This habenular projection arises primarily from large neurons in the medial part of the lateral habenula and also from another group of small cells immediately adjacent to the medial habenular nucleus. A non-reciprocal connection of the dorsal raphe nucleus to the locus coernuleus was also found. On the basis of these results and the data available in the literature on the possible neurotransmitters used by these various structures, it is suggested that the dorsal raphe nucleus may play an important role in brain stem modulation of neostriatal function.     

Interactions for dichotomous variables in repeated measures designs.

Describes a method for analyzing interactions in a repeated measures design for a dichotomous dependent variable. The method is based upon the Cochran Q model but is restricted to the case in which a planned analysis is adopted. The model is illustrated for ordered and unordered independent variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Undermining extrinsic interest.

Comments on F. M. Levine and G. Fasnacht's (see record 1975-07966-001) article on token learning, focusing on (1) the validity of the overjustification hypothesis, (2) the nature of intrinsic interest, and (3) the implications of overjustification studies for token economies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)