Bonds are flat this morning with US Treasuries opening with a slight negative bias and mortgage-backed securities (MBS) issued by Fannie Mae and Freddie Mac opening with a slight positive bias.  Stock futures are up on action in Europe, on news of continued European Central Bank purchases of under-pressure euro-area government bonds.  Also, Japan announced that it would buy debt issued by the Eurpean Financial Stability Facility.  One of the lynch pins of mortgage rates staying at or near current levels is investor fear over European debt.  While concerns about the crisis eased toward the end of last year, they flared again at the beginning of this year.  As such actions by the European Central Bank or other large debt buyers like Japan to support the European bailout efforts are important signals for investors trying to determine which way to place their bets, particularly given the higher inflation expectations which traditionally place pressure on bonds.