A deglitching circuit for the AA50 D/A converter

Switching transients or “glitches” are frequently encountered in signal processing applications involving digital-to-analog (D/A) conversion. A low-cost “deglitching” circuit is described and implemented for the Digital Equipment Corporation AA50 D/A converter option on the PDP-8/e minicomputer. Switching transients were eliminated using a noninverting, unity-gain sample-and-hold circuit (employing Datei System’s SHM-IC-1). Switching transients were reduced to below-noise levels across a wide range of output levels and sampling rates.     

A self-contained microcomputer system for psychological testing

This paper describes a newly available microcomputer system for the on-line administration, scoring, and interpretation of psychological tests. User response to the system is reported. Results of a validity study of the system’s Minnesota Multiphasic Personality Inventory interpretative program are presented.     

A system for the assessment of human performance in concurrent verbal and manual control tasks

A multipurpose laboratory system incorporating a voice interactive terminal and graphic display system is described. The facility is designed to investigate some aspects of human performance on concurrent verbal and tracking tasks. The results of a pilot study showing decrements in dual-task performance are reported.     

A multipurpose activity platform utilized in the open-field setting

An automated multipurpose activity platform (MAP) that can be used to measure activity in the horizontal plane is described. Detection of the position of a small-bodied animal is based on completion of an electronic circuit in one or several cells of a 21 by 21 matrix below the floor. The MAP is constructed on the basis of an 11 by 11 matrix, but, through electronic averaging, operates functionally on the basis of a 21 by 21 matrix. The MAP has no built-in data storage facility and needs to be interfaced with a recording system. The system has been successfully utilized in measuring open-field activity of the rats.     

A technique for converting from intravenous drug self-administration to liquid reinforcement

A rapid inexpensive technique for changing from intravenous drug self-administration (DSA) to liquid reinforcement is described. Utilizing a standard peristaltic-type infusion pump typically used in DSA experiments and a specially designed drinking cup, the changeover from intravenous DSA to liquid reinforcement can be accomplished in a few minutes at a cost of less than $10.     

An investigation of the perceptual basis of redundancy gain and orthogonal interference for integral dimensions

Redundancy gain and orthogonal interference for height and width were demonstrated in two experiments using a relative coding task with number of intertrial repetitions controlled. Orthogonal interference was shown to be perceptually based rather than simply an intertrial repetitions effect as suggested by Felfoldy (1974). These results from a relative coding task were discussed in terms of the previous multidimensional processing literature. It was concluded that Lockhead’s (1972t model has been applied too generally. An alternative model (a parallel, dimensional analysis stage followed by a stage in which dimensional information is integrated) was suggested.     

Comparative evaluation of the Job Club program with welfare recipients

About 1000 WIN welfare clients were selected in five cities: Harlem, New Brunswick, Milwaukee, Wichita, and Tacoma, and half were randomly assigned to the Job Club program. Of the continuing clients, 87% of the Job Club sample obtained jobs vs 59% of the Control sample at the 12-month follow-up and 80 vs 48% at 6 months. The Job Club was more effective in each of the five cities, for men and women, for high school graduates or dropouts, for blacks, whites, and Spanish, for handicapped or nonhandicapped, veterans or nonveterans, the young and the older, and for those required to participate as well as those who volunteered. The jobs obtained by the Job Club clients were comparable to the Control clients' jobs in terms of mean salary, full-time status, and type of job, and were more likely to be enduring, nonsubsidized, and obtained by the job-seeker's own efforts. Job Club members obtained employment in a median of six sessions (mean of 11); 90% obtained jobs within 23 sessions. Follow-up questionnaire data indicated comparable job retention in the two samples but slightly greater advancement and job satisfaction for the Job Club clients. The method appears to assure employment to virtually all participating welfare clients.