The Development of Spark Discharges in Hydrogen

Streak photography has been used to supplement the earlier shutter photo. graphic investigation of Doran and Meyer (1967) using the same coaxial cable discharge circuit. Additional information has also been obtained from measurement of the potential distribution between the electrodes at two stages in the spark development. Redistribution of space charge is shown to give rise firstly to a transient diffuse glow discharge that has a close similarity with a normal d.c. glow discharge. It has also been shown that, even while the diffuse glow discharge expands, a partial constriction occurs in which most of the current flows along a narrow axial column. The resulting maximum in electron density eventually causes a rapid increase in dissociation of molecular hydrogen on the axis of the discharge brought about by a rise in the gas temperature. Owing to its greater electrical conductivity this axial column soon carries the entire current and the discharge becomes filamentary though still being maintained by a high cathode fall field, which exists until a sudden change in the cathode mechanism gives rise to the low voltage arc channel. Both the filamentary glow and arc columns are observed to expand according to an r cc ti law.

Tape recordings of the ECG of active men. Limitations and advantages of the Holter-Avionics instruments

The electronic and mechanical characteristics of the Holter-Avionics instruments for recording and analyzing the electrocardiogram of active men have been measured in the laboratory, and during carefully standardized 6-hour recordings of 385 active subjects. Although late model recorders have a cumulative timing error of less than 1%, the frequency response of the system is limited at both the upper and lower ends of the range, producing significant distortion of the complex. Scanning the taped data at 60 times real-time is a helpful screening procedure, but accurate analysis of records requires photographic write-out of R-R intervals with real-time scanning and analysis of all potential areas of abnormality. If records are made with subjects under constant observation and stop-watch timed, they can yield significant data on phenomena of rate, rhythm, and conduction, under a variety of circumstances and over long periods of time; but changes in the shape of the ST segment and T wave must be interpreted with great caution because of distortions produced by the recording system and by changes in position and activity.

Enterogastrone Inhibits Eating by Fasted Mice

In mice fasted for 17 hours, administration of enterogastrone purified from hog duodenum reduced the food intake. This effect was greatest during the first 30 minutes, but the cumulative reduction continued for at least 4 hours. Other peptides prepared from hog duodenum or colon, as well as glucagon, secretin, glucose, and bovine serum albumin, were ineffective.