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R Zwick

Publications and source records attributed to R Zwick.

10 recordsLinked to original sources
PubMed1986

Testing pairwise contrasts in one-way analysis of variance designs.

Research in the behavioral and health sciences frequently involves the application of one-factor analysis of variance (ANOVA) models. The goal may be to compare several independent groups of subjects on a quantitative dependent variable or, alternatively, to compare measurements made on different occasions or under different conditions on a single group of subjects. If there is reason to believe that there are differences among the groups (or occasions or conditions), the researcher frequently wishes to compare the means in a pairwise fashion. Although the procedures for conducting omnibus hypothesis tests for one-factor ANOVA models are familiar to most researchers, the issues that must be considered in choosing pairwise multiple comparison procedures (MCPs) are not as well understood. In this paper, the selection of pairwise MCPs for one-factor ANOVA models is considered, following a discussion of Type I error and power issues as they apply to the testing of multiple hypotheses. Although the paper focuses on the independent-sample case, repeated measures models are considered briefly as well.

Analysis of Variance↗
PubMed1984

The use of reception checks in client pretherapy orientation research.

The psychotherapy research literature abounds with evidence of the problems of premature termination and unsatisfactory outcome, especially among low-SES clients. In attempting to enhance the success rate of therapeutic services, some researchers have instituted pretherapy orientation procedures that convey information to clients with regard to the goals and processes of therapy. Although research in this area has continued for two decades, the efficacy of such procedures has not been established firmly. Even when orientations have demonstrable positive effects, the processes through which these results are achieved usually remain unknown. In order to gain an understanding of these mechanisms, researchers must employ measures to assess directly the immediate effects of the orientation. In a recent study, the authors developed a questionnaire to determine whether clients had attended to and understood a pretherapy videotape presentation and whether they recalled the material 1 month later. The results obtained on this measure facilitated the interpretation of the overall research findings.

Consumer Behavior↗
PubMed1982

The client satisfaction questionnaire. Psychometric properties and correlations with service utilization and psychotherapy outcome.

An 18-item version of the Client Satisfaction Questionnaire (CSQ-18) was included in an experimental study of the effects of pretherapy orientation on psychotherapy outcome. The psychometric properties of the CSQ-18 in this study were compared with earlier findings. In addition, the correlations of the CSQ-18 with service utilization and psychotherapy outcome measures were examined. Results indicated that the CSQ-18 had high internal consistency (coefficient alpha = .91) and was substantially correlated with remainer-terminator status (rs = .61) and with number of therapy sessions attended in one month (r = .54). The CSQ-18 was also correlated with change in client-reported symptoms (r = -.35), indicating that greater satisfaction was associated with greater symptom reduction. Results also demonstrated that a subset of items from the scale (the CSQ-8) performed as well as the CSQ-18 and often better. The excellent performance of the CSQ-8, coupled with its brevity, suggests that it may be especially useful as a brief global measure of client satisfaction.

Community Mental Health Centers↗
PubMed1976

Effect of motilin on the lower oesophageal sphincter.

The effect of motilin on lower oesophageal sphincter (LES) pressure has been studied in unanesthetised specially trained dogs using an infusion manometric technique. Motilin produced significant rises in resting pressure and contractions of the LES after doses ranging from 0-009 mug/kg to 0-05 mug/kg. Doses greater than 0-05 mug/kg resulted in repetitive high amplitude contractions. Atropine 30 mug/kg completely abolished the effect of the lower doses of motilin. Higher doses of motilin in atropinised dogs still caused a small rise in baseline pressure and contractile activity still appeared. Hexamethonium 2 mg/kg resulted in both a diminished rise in LES pressure and the disappearance of contractions after motilin. Hexamethonium and atropine together completely abolished the LES response to motilin. We conclude that motilin increases LES pressure by acting on preganglionic cholinergic neurones to release acetylcholine which excites other cholinergic neurones supplying the circular muscle of the LES.

Animals↗
PubMed1976

Mechanism of action of pentagastrin on the lower esophageal sphincter.

The effects of pentagastrin on lower esophageal sphincter (LES) pressure has been studied in trained, unanesthetized dogs. LES pressure was monitored by an infusion manometric technique. Increasing doses of pentagastrin up to 3 mug/kg given as an i.v. bolus resulted in increasing rises in LES pressure; larger doses resulted in a lesser effect of shorter duration. Increasing i.v. boluses of methacholine produced greater increases in LES pressure up to a maximum of 5 mug/kg; higher doses had similar effects. Atropine (50-100 mug/kg) slightly diminished the response of the LES to 2 or 6 mug/kg of pentagastrin. In large doses (500-2,000 mug/kg), atropine did not diminish the response to pentagastrin and prolonged the response of 6 mug/kg pentagastrin. Hexamethonium (2 mg/kg i.v.) depressed the peak response to 3 mug/kg pentagastrin slightly but the response to 6 mug/kg was increased and prolonged. Propranolol (2 mg/kg i.v.) significantly prolonged the effect of 6 mug/kg pentagastrin on the LES. We conclude that the stimulatory effect of pentagastrin is mainly due to a direct action on the LES. A lesser stimulatory effect is due to an action on preganglionic cholinergic neurons. Large doses of pentagastrin have both stimulatory and inhibitory effects. The inhibitory effect is mediated at least in part via preganglionic neurons acting through adrenergic receptors. Ganglionic transmission of the effect may be through muscarinic as well as nicotinic receptors.

Acetylcholine↗
PubMed1974

[Child and death].

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Anxiety, Separation↗