Tokyo stocks opened higher Tuesday, tracking overnight gains on the technology-heavy Nasdaq index, although the market was weighed by uncertainty after Ukraine and Russia agreed to meet again for cease-fire negotiations. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 364.87 points, or 1.38 percent, from Monday to 26,891.69. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was up 18.01 points, or 0.95 percent, at 1,904.94. Gainers were led by marine transportation, service and machinery issues. At 9 a.m., the dollar fetched 115.08-10 y…