Tokyo stocks ended mixed Tuesday, with the Nikkei down for a fifth straight day, as earlier gains in tech issues were largely wiped away amid a risk-off mood ahead of earnings releases by major companies. The 225-issue Nikkei Stock Average ended down 4.61 points, or 0.01 percent, from Monday at 39,594.39. The broader Topix index finished 5.86 points, or 0.21 percent, higher at 2,833.39. On the top-tier Prime Market, gainers were led by marine transportation and bank issues, while major decliners were precision instrument and electric power and gas issues. The U.S. dollar weakened to the lower …