In anticipation of a global summit on the food crisis, the United Nations called on world leaders on Wednesday to agree to urgent measures to ease demand for grains and alleviate high food prices. The report, by the Food and Agriculture Organization of the United Nations, suggests that countries might need to reconsider policies that encourage the production of ethanol and other biofuels. The report also suggests that the food summit in Rome, which runs from June 3 through June 5, gives world leaders a chance to re-launch a war on hunger. "This is a unique moment in history: for the first time in 25 years, a fundamental incentive