Seoul shares opened lower Tuesday, bucking overnight gains on Wall Street, on profit-taking after Samsung Electronics released its preliminary second-quarter earnings estimate. The benchmark Korea Composite Stock Price Index fell 294.53 points, or 3.7 percent, to 7,756.80 at the opening bell. Local technology stocks fell on profit-taking after Samsung Electronics estimated its April-June operating profit at 89.4 trillion won ($58.4 billion), beating market forecasts. The estimate reflects provis