LONDONKayla Harrison gave the U.S. its first judo gold medal in Olympic history, taking the 78-kilogram title Thursday at the London Games.Harrison, who lives and trains in Wakefield, defeated Britain's Gemma Gibbons in a final she dominated from the start, getting a stronger grip on Gibbons and managing to throw her twice.Her medal is the U.S.' second in judo this week: Teammate Marti Malloy won a bronze in the women's 57-kilogram division.Harrison, world No. 4 and a former world champion, was in top form, dispatching many of her opponents with a match-ending ippon move, one in less than a minute. Harrison said she was focused on the gold."This is my purpose," she said.When the national anthem was played while Harrison was on the podium, she wept."I was just kind of reflecting back on my life and everything it's taken to get here and everything I've gone through," she said. "I'm just so honored to be America's first gold medalist in judo. I'm happy to realize my dream."The bronze medals were won by Audrey Tcheumeo of France and Mayra Aguiar of Brazil.