DOVER, Del. (AP) — DuPont's agricultural sales suffered and its operating costs rose during extensive winter storms that dragged on first-quarter earnings, although volumes increased in the company's industrial segments and margins improved in almost every one of them. The DuPont Co. reaffirmed its outlook for full-year operating earnings of $4.20 to $4.45 per share, compared to $3.88 per share last year, based on anticipated growth in global industrial market demand.