CHICAGO (AP) _ Grain futures were mostly higher Thursday on the Chicago Board of Trade. Sept. corn gained 4 cents at $5.13 a bushel. Sept. wheat was up 0.25 cent at $7.13 a bushel. Sept. oats was off 9.75 cents at $3.46 a bushel. Sept. soybeans was up 17.5 cents at $13.18 a bushel. Beef...