World markets won a reprieve on Tuesday after three days of heavy selling that wiped trillions of dollars off the value of shares, but the mood was cautious with a focus on whether Washington might negotiate on some of its aggressive tariffs. Asia stocks bounced off 1-1/2 year lows, European shares opened broadly higher and U.S. stock futures pointed to a positive open for Wall Street where shares fell to their lowest in over a year on Monday, before steadying. U.S. 10-year Treasury yields were steady after posting their biggest one-day jump in a year on Monday and the dollar,...