A method for calibrating the spatial coordinates of a visual display to high accuracy

High-resolution CRT displays are subject togeometric distortion: lines that are straight in the internal coordinates of the graphics software and hardware are curved when projected onto a plane in the observer’s line of sight. As the available resolution of CRT screens increases, it becomes more difficult to measure and correct for this distortion. We present a simple, highly accurate method for determining the mapping between internal coordinates and the viewing plane. It requires that an observer, using a calibration program, adjust triples of displayed points until they are collinear. A metal straightedge placed between the observer and the screen aids in this judgment. We describe the calibration of an IBM Enhanced Graphics Display in high-resolution mode (350 × 640 pixels), and illustrate how to use the estimated mapping to choose internal coordinates to draw undistorted figures that are accurate to within 0.5 pixel. The method can be used to assess or to correct the accuracy of visual displays. The method is relevant to experiments in spatial vision, spatial perception, perception of dot patterns, and any application in which geometrically accurate stimuli are required.     

More on millisecond timing and tachistoscope applications for the IBM PC

This paper describes a method of establishing time intervals at a precision of better than 1 msec, using QuickBASIC 4.0, for running real time experiments on an IBM PC without an 8087 coprocessor. This method is far superior to the TIMER function provided by BASIC, which has a precision of only 110 msec. Also described is an assembly language subroutine that corrects a problem in QuickBASIC 3.0 and QuickBASIC 4.0 to allow proper switching between screens in the CGA text mode for use of the PC as a tachistoscope. A tachistoscope program listing shows how to use the screen subroutine and how to establish intertriai intervals and record reaction times using the timing subroutines.     

A high-gain,low-noise amplifier for EEG

This paper describes an amplifier for an electroencephalograph with gain of 1×10⁴ to 1×10⁶ and made entirely of commercially available IC components. The two-stage amplifier has a preamplifier stage with fixed gain of 1000, and a second stage with variable gain from 1 to 100. The final stage, an anti-aliasing filter, adds a gain of 10 to the signal. The circuit has high common mode rejection, low input bias current, very low noise characteristics, low offset voltages, and offset nulling capability built into the circuit.     

Beyond medical ethics: New directions for philosophy and medicine

A unique relationship exists between physicians and philosophers — one that expands on the constructive potential of the liaison between physicians and, for example, theologians, on the one hand, or, social workers on the other. This liaison should focus in the scientific aspects of medicine, not just the ethical aspects. Philosophers can provide physicians with a perspective on both the philosophy and the history of medicine through the ages — a sense of how medicine has adapted to the social cultural and ethical needs of each period. This perspective, while emphasizing medicine asscience, should not be limited to matters of methodology, or to criteria for distinguishing science from other intellectual pursuits, but should be concerned also with the history, sociology and politics of science. Both physicians and philosophers stand to gain from a strengthening of their active liaison now as never before; but most of all, the public will be the beneficiary.     

Converging evidence that fear of success is multidimensional

Fear of Success (FOS) was originally conceived as a unidimensional motive. However, there is both theoretical and empirical support for the hypothesis that FOS is multidimensional. We factor analyzed the responses of 236 undergraduates to twenty-oneConcern Over the Negative Consequences of Success items and found four factors. Our four factors show considerable overlap with dimensions based on theoretical accounts of FOS etiology as well as with the factor structures obtained from two other factor analytic studies. Thus, there is converging evidence that FOS is multidimensional. The relationship between multidimensional FOS and a multidimensional approach to achievement motivation is discussed.     

Maternal handling and motor development: an intracultural study

Citing a distinction between informal and formal routines used by mothers in handling their infants, we examined formal handling routines, in which the caregiver acts in a pedagogical manner; these routines are widespread in many non-Western countries. We hypothesised that formal handling serves to facilitate gross motor development during early infancy. To examine this hypothesis, the effects of a Jamaican formal handling routine on a broad range of developmental outcomes was examined. Results showed that the effects were specific to early gross motor development and in particular to postural control along the vertical axis of the body. Information is also provided on other aspects of Jamaican child care. It seems that the handling routine forms part of a folk (developmental) medicine system and may serve not only to promote child health but also as a sort of developmental neurological examination.