Precision measurements of NH(3) spectral lines near 11 microm using the infrared heterodyne technique.

Absolute line-center frequencies for eleven lines of ammonia in near coincidence with CO(2)-laser transitions have been determined to accuracies of +/-3 MHz by infrared heterodyne detection. These results were obtained by heterodyning a blackbody with a stable, grating-tuned CO(2) gas laser. A discussion of the apparatus and method of calculation, including error analysis, is presented.

Comparative study of cardiovascular function and ventricular premature complexes in smokers and nonsmokers during maximal treadmill exercise.

Maximal treadmill exercise tests were performed by 586 male members of the Indiana State Polic Force who were free of clinical evidence of cardiovascular disease. The study population was categorized into groups according to cigarette smoking experience and subgroups according to age and number of pack-years of exposure. There were 176 nonsmokers (30 percent), 268 current smokers (46 percent) and 142 former smokers who had abstained for at least 1 year (24 percent).

Posterior leaflet motion in mitral stenosis.

The echocardiographic features of mitral valvular motion in a patient with classic rheumatic mitral stenosis are presented. Two unusual features were noted, and the important of careful echocardiographic scanning of the mitral valve is imphasized. The theories for the classic echocardiographic abnormalities of mitral stenosis are briefly considered in light of the findings in this case.

Prevalence and reproducibility of exercise-induced ventricular arrhythmias during maximal exercise testing in normal men.

The occurrence of ventricular arrhythmias at rest or during ordinary daily activities has been implicated as a risk factor for future coronary-related events and sudden death. However, the clerical significance of exercise-induced ventricular arrhythmias remains uncertain. To assess the prevalence and reproducibility of such arrhythmias, two serial maximal treadmill exercise tests were performed in a study population of 543 male Indian State policemen at an average interval of 2.