Through the dark days of the financial crisis, and the grey days of the halting recovery that have followed, investors have always been able to count on backing from two sources - Ben Bernanke and Beijing. They have provided stimulus, mainly by pumping funds into the U.S. and Chinese economies in various ways, when other pillars of support had become unreliable. That helps to explain why global financial markets took such a beating last week when both signaled that they are getting tired of being leant on so heavily. Bernanke, the chairman of the U.S. Federal Reserve, set a timetable at last week's Fed meeting for the central bank to reduce the size of its bond buying program with a view to ending it by the middle of next year. Meanwhile, his counterparts at the People's Bank of China (PBOC) engineered a cash crunch as a warning to overextended banks - and this from a central bank that has previously always provided liquidity when cash conditions tightened. A lot will