The distribution of axial velocities in the pulmonary artery must be determined to describe accurately the flow in the pulmonary artery. Previous studies in our laboratory have demonstrated the complexity of the velocity profile in the pulmonary trunk and the branch pulmonary arteries with normal and altered pulmonary blood flow. These findings have demonstrated a skewed, parabolic mean velocity profile in the pulmonary trunk under normal hemodynamic conditions. To determine the effect of left-to-right intracardiac shunting on the distribution of axial velocities in the pulmonary artery, an animal model of atrial and ventricular shunting was used. In both models, the distribution of mean axial velocities remained skewed and parabolic with the higher mean velocities recorded toward the anterior wall.

The investment performance of professionally managed portfolios, in general, and mutual funds, in particular, has been the subject of considerable attention in finance. Fama [9] has suggested that overall portfolio performance be broken down in such a manner that the individual sources of performance can be identified. Two basic sources are: (1) the ability of the portfolio manager to forecast price movements of individual common stocks relative to stocks in general (selectivity or microforecasting); and (2) the ability to forecast the direction of the stock market relative to fixed income securities (timing or macroforecasting).