Tokyo stocks opened sharply higher Tuesday, with the Nikkei index trading at a new 34-year high, led by tech buying after the U.S. Dow Jones index hit a new all-time high overnight. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 656.86 points, or 1.78 percent, from Friday to 37,554.28. The broader Topix index was up 25.95 points, or 1.01 percent, at 2,583.83. Japanese markets were closed Monday for a public holiday. On the top-tier Prime Market, gainers were led by insurance, service and electric appliance issues. At 9 a.m., the U.S. dollar fetched 149.40-41 yen co…