Agence France-Presse: Amid a surge in food prices blamed in part on US expansion of corn-based ethanol production, lawmakers, experts and industry officials are urging the government to rethink a new law mandating alternative fuels. The United States is the world’s top producer of corn-based ethanol, which the administration of President George W. Bush sees as a way of reducing dependence on foreign oil and curb fossil-fuel emissions, the main source of man-made global warming. Politicians are under …