Measurements were made of the contrast required to see the direction of motion of drifting gratings (Part 1) and of moving bars (Part 2). The spatial frequency at which least contrast is required to see sinusoidal gratings decreases as their velocity increases, but peak sensitivity is identical at all velocities up to 800 deg/sec. Similarly, the wider a single bar, the higher the velocity at wh...

The photoacoustic effect may be exploited for the detection and localization of gas leaks from otherwise sealed components. The technique involves filling the test component with a tracer gas, and radiating the component to produce photoacoustic sound from any leak site where tracer gas is present. This paper describes demonstration experiments utilizing 10.6-micro radiation from a carbon-dioxi...

Auditory thresholds were determined for infants and adults to half-octave bands of noise centered at 10,000 and 19,000 hertz. Adults were significantly more sensitive than infants at 10,000 hertz, but at 19,000 hertz, adults and infants had comparable thresholds. In 1876, Sir Francis Galton reported his invention of a brass whistle for the purpose of testing the audibility of "shrill notes" (1)...

Real-time PCR methods have become widely used within the past few years. However, real-time PCR is rarely used to study chronic diseases with low pathogen loads, presumably because of insufficient sensitivity. In this report, we developed an integrated nucleic acid isolation and real-time PCR platform that vastly improved the sensitivity of the quantitative detection of the intracellular bacter...