Prostate-specific antigen (PSA) is a substance produced by the prostate gland. Elevated PSA levels may indicate prostate cancer, a noncancerous condition such as prostatitis, or an enlarged prostate.
Dolby Digital, formerly known as AC-3, is a digital audio coding technique that reduces the amount of data needed to produce high quality sound. Dolby Digital takes advantage of how the human ear processes sound.
Dolby Digital audio is available via laser discs, DVD-Video discs, DVD-ROM discs for computers, digital cable systems, direct broadcast satellite (DBS) systems, and digital broadcast TV (DTV). They are usually identified with the Dolby Digital logo.