Discovery Communications has shaken up its executive structure. Eileen O'Neill has been named group president of Discovery Channel and placed in charge of Velocity and Science Channel. TLC, previously under O'Neill, is now under the purview of Marjorie Kaplan, group president of TLC and Animal Planet. Henry Schleiff has been named group president of Investigation Discovery, Destination America and American Heroes Channel. He will also oversee Discovery Fit & Health, formerly one of O'Neill's channels. Dan Holloway has the story.