Nikkei stock index falls in morning as gains locked in

The Nikkei stock index dropped Tuesday morning as investors locked in gains after it closed at an all-time high above the 40,000 mark the previous day.According to Kyodo News, the 225-issue Nikkei Stock Average fell 168.62 points, or 0.42 percent, from Monday to 39,940.61. The broader Topix index w