The U.S. dollar was weak in the upper 155 yen zone Thursday morning in Tokyo after the chief of the U.S. Federal Reserve said it is unlikely to raise interest rates, while another suspected yen-buying intervention by Japan also pushed the yen higher. The U.S. currency briefly fell to 153.00 yen overnight from the upper 157 yen range, following what was believed to be a yen-buying, dollar-selling operation by Japan to halt the yen’s decline. Japanese authorities are believed to have conducted an intervention on Monday after the dollar topped 160 yen at a fresh 34-year high. The dollar’s latest …