Movers & Shakers: Tuesday���s biggest gaining and declining stocks

of Tuesday���s U.S. stock-market open: Dean Foods Co.���s (NYSE:DF) Medifast Inc.���s (NYSE:MED) Vonage Holding Corp.���s (NYSE:VG) Dice Holdings Inc.���s (NYSE:DHX) MannKind Corp.���s (NASDAQ:MNKD) Universal Display Corp.���s (NASDAQ:PANL...