MEXICO CITY — Mexican congressmen called for a federal investigation of potential drug cartel ties to the nation's beauty pageants Friday after a 23-year-old beauty queen was arrested on suspicion of drug and weapons violations. Congressional leaders warned that cartels may have infiltrated contests to launder money, and said a full investigation was needed. To many, former preschool teacher Laura Zuniga, named Miss Sinaloa in the drug-plagued northern state's annual beauty contest, symbolizes declining ethics in Mexico. "It is very sad. What we are seeing is a loss of values among young people," said Rep. Juan Francisco Rivera, who heads...