NEW YORK (Reuters) - Last week's wild gyrations in global financial markets almost certainly exposed the vulnerability of U.S. state and local authority public pension funds which have piled into riskier assets in recent years, according to actuaries and other pension experts. Based on data from the Federal Reserve, the funds are sitting on nearly $4 trillion in assets that are more than 70 percent exposed to equities and other riskier assets, such as commodities and hedge funds. And some states with massive pension funding deficits, such as Illinois, are likely most in danger of suffering big losses given their...