CHICAGO (AP) _ Grain futures were mixed Friday on the Chicago Board of Trade. Dec. corn was down 3.75 cents at $4.47 a bushel. Dec. wheat fell by 1.75 cents at $6.03 a bushel. Dec. oats gained 1 cent at $3.44 a bushel. Nov. soybeans was up 1 cent at $12.21 a bushel. Beef was...