The psychologist and the visual scientist often need a rapid and silent means of interrupting or attenuating light. By using fluorescent lamps, glow-modulator tubes, light-emitting diodes, electroluminescent panels or cathode-ray tubes, it is sometimes feasible to modulate the light source : but often, because the light must be very intense or because particular spectral bands are required or b...

Active-matrix liquid crystal displays (AMLCDs) are light-modulating devices that generate images by differentially transmitting a nearly uniform luminous field provided by a backlight. While emissive displays exhibit a quasi-Lambertian emission with almost constant contrast at off-normal viewing, the anisotropy of the electro-optic effect that controls light transmission in AMLCDs causes a pixe...

The Online Distance Learning System from CRT Brasil Telecom (Brazilian Telephone Company), has showed that technology and education found a commum point to perform good educational methodologies.

The cathode ray is practically free from inertia and therefore an ideal instrumentality for studying variations in electrical potential. A cathode ray oscilloscope with an amplifier system of high frequency response and an expanded time scale, 330 mm. per second, were employed to record electrocardiograms. Such tracings revealed considerable notching, slurring, and other peculiarities not seen ...