Task: Text Categorization
Input (English): This effect can be used to measure the velocity width term of the Tully-Fisher relation, and, with the Mossbauer effect, a tower at the Jefferson Laboratory was used by Pound and Rebka to test a variety of it. Canal ray tubes were used by Ives and Stilwell to investigate the transverse version of this effect. The introduction of the Lorentz factor as the inverse of the square root of one minus the ratio of the velocity of the source and the speed of light allows for the calculation of the relativistic form of this effect, which can be used to measure the radial velocity of galaxies with blueshift and redshift. For 10 points, name this effect responsible for the frequency change of a passing siren.
Output (English): Science