Dow Chemical posted stronger-than-expected fourth-quarter operating earnings and revenue Thursday and said it remains focused on the closing of its $130 billion merger with DuPont Operating earnings for the three months ended in December were 99 cents a share, the company said, well ahead of estimates of 88 cents, and up 6.45% from the same period last year. Headline results, however, indicated a quarterly loss of 3 cents a share.