European equities had their 42nd straight month of earnings downgrades in September, with an average of 100 downgrades per working day since March 2011, says a recent report from UBS. That’s not quite as bad as Japan’s 51-month downgrade streak in the early nineties, and fortunately there are signs that estimates could finally turn around. “Bottom-up consensus earnings estimates have tended to be perennially too optimistic across many Global Equity markets. But even by these standards, the sheer persistence of downgrades in Europe over recent years has been dramatic,” write UBS strategists Nick Nelson and Karen Olney. Europe: Growth estimates…