Kazakhstan's Sarsekbayev wins welterweight gold

    Bakhyt Sarsekbayev of Kazakhstan has won the welterweight boxing gold medal, upsetting Cuban favorite Carlos Banteaux 18-9.     Sarsekbayev had little international success before the Olympics, but he was quicker and more accurate than Banteaux on Sunday. Sarsekbayev controlled the bout to win Kazakhstan's fifth boxing gold.     Banteaux's loss means amateur powerhouse Cuba...