Oil and gold prices are higher at the end of the first quarter than they were at the beginning. An index that tracks the U.S. dollar's strength edged lower. Yields on the benchmark 10-year U.S. Treasury note fell nearly 20 percent in the first three months. Higher gold and lower Treasury yields suggest investors are nervous about economic conditions. A weaker dollar is good for U.S. exports and U.S. corporate earnings made in foreign currencies. Oil prices and stocks have been closely tracking each other as investors use crude and other base commodities as a measure of global economic health.