US stock indices seemed to be heading for a moderately positive start to trading on Thursday, before reports emerged from Japan that dented the market's confidence.  Futures for the S&P 500 were down 0.25% at the time of publication, having been up almost as much the other way an hour earlier. Dow Jones futures were down 0.5% and those for the Nasdaq were 0.3% in arrears.  The spark that hit markets was a report that Japan intends to push back against any US effort to bring it into an economic bloc aligned ...