Reaction time as a function of the intensity and probability of occurrence of vibrotactile signals

Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion.     

Police evaluation research: an experimental and cost-benefit analysis of a helicopter patrol in a high crime area

The significance of a helicopter patrol procedure directed toward prevention of home burglaries was evaluated from experimental and cost-benefit perspectives. The helicopter patrolled one city zone from 9 a.m. to 5 p.m. for two 12-day periods. Each 12-day period was separated by a baseline period in which only normal patrol-car levels were maintained. Significantly reduced burglary levels during the intervention periods, compared to baseline periods, documented the experimental significance of the helicopter procedure. The cash costs of implementing the patrol procedure were compared to two estimates of the resulting cash benefits. This latter cost-benefit analysis was supplemented by a discussion of the intangible costs and benefits of the helicopter procedure. Taken together, these analyses documented that the marginal costs of the helicopter intervention were exceeded by all estimates of benefits.     

Evaluating the Psychometric Properties of the Teamwork KSA Test

The Teamwork KSA Test has been a welcome addition to the practitioner's selection toolkit as well as a useful measure for teamwork researchers. We analyzed the psychometric properties of the Teamwork KSA Test and recognized correlates of the construct using three samples of working individuals recruited through a university (N = 241, N = 230, N = 332) and found slim evidence for a factor structure of the underlying constructs. Furthermore, classical reliability estimates did not meet traditional psychometric standards. Total TKSA scores predicted self‐ratings and instructor ratings of teamwork in two of the samples; effect sizes were small.     

Eighteen month test-retest stability of the youth self report in a sample of Catalonian adolescents

The aim of this study is to assess the test-retest stability of the Spanish version of Youth Self Report after 18 mo. for a sample of 357 Catalonian high school students (158 boys and 199 girls). At Time 2 the girls' scores increased on Delinquent and Aggressive Behavior scales and, therefore on Externalizing scores. At Time 2 the boys' scores increased on Attention Problems and Delinquent Behavior and decreased on Anxious/Depressed, Social Problems, and Internalizing scales. Significant differences in the remaining scales were not observed. The test-retest intraclass correlations for the broad-band scales ranged between .62 (Internalizing) and .68 (Externalizing) and for the narrow-band scales between .37 and .67. The correlations for girls and boys were similar but slightly higher for girls on Anxious/Depressed and Thought Problems.     

Factor structure of coping: two studies of mothers with high levels of life stress

Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to investigate the factor structure of coping in mothers with high levels of life stress. In Study 1, EFA of the Coping Orientation to Problems Experienced (C. S. Carver, M. F. Scheier, & J. K. Weintraub, 1989) in a sample of mothers of full-term or very low birth weight 2-year-old children yielded 7 reliable coping factors. Each factor accounted for significant variance in at least 1 of 6 outcomes measuring maternal-child well-being. In Study 2, CFA was used to cross-validate the EFA model on the basis of the responses of mothers of 2-year-old children with prenatal polysubstance exposure. CFA results revealed a moderately good fit, confirming the factor structure in a 2nd, independent sample of mothers with high levels of life stress.     

Non-dissociation of Lomer–Cottrell dislocations and 〈110〉{001} slip in silicon

Abstract

Two unexpected features have been revealed by transmission electron microscopy investigations of deformed silicon bicrystals: (a) slip of a/2 〈110〉 dislocations on {001} planes and (b) non-dissociation of Lomer–Cottrell dislocations formed by intersecting slip dislocations.     

Supersonic crack motion in a harmonic lattice

Antiplane shear cracks in a harmonic square lattice have been studied in a molecular dynamics simulation. They can reach velocities larger than the shear wave velocity.     

Social evaluation research: the evaluation of two police patrolling strategies

In most social evaluation research it is difficult to achieve the degree of experimental rigor possible in an applied behavioral study. This study illustrates how the evaluation researcher can increase experimental rigor in the analysis of social interventions. In the first evaluation, a variation of the time-series design that offered maximum experimental control given the limitations of the situation, was employed to evaluate the effects of a specialized home-burglary police patrol. This design revealed that no effects could be attributed to the patrol. In the second evaluation, a multiple baseline-like design was possible in determining the effects of a police walking patrol. This design revealed that the patrol produced an increase in crime reporting but not in arrests. Social interventions often occur in a manner that allows varying degrees of experimental analysis. The evaluation researcher must attain optimal experimental analysis given the limitations of each social intervention.