Align Technology Inc. (ALGN: chart), invisible braces maker, reported a fourth-quarter net loss of $17.3 million, or 27 cents per share compared with the same quarter last year when the company posted a profit of $528,000, or a penny per share. Revenue climbed to $55.2 million versus $51.2 million last year.

Pilgrim''s Pride Corp. (PPC: chart), chicken and turkey processor, said that it swung to a first-quarter loss of $8.7 million, or 13 cents per share, compared with a year-ago income of $25.7 million, or 39 cents per share. Revenue fell fractionally to $1.34 billion. Pilgrim''s Pride said sharply higher costs for corn hurt results.

MDU Resources Group (MDU: chart), oil services company, said that its fourth-quarter net income rose to $82.4 million, or 45 cents per share from $73.1 million, or 40 cents per share, during the same period in 2005. Revenue improved 8% to $1.09 billion from $1.01 billion during the same period a year earlier.

Diebold Inc. (DBD: chart), makes automated teller and voting machines, said it earned $27.1 million, or 41 cents per share, in the fourth quarter, up from $10.4 million, or 15 cents per share, in the same period a year ago. Excluding restructuring and other charges the company said it would have earned 77 cents per share. Revenue climbed to $825.4 million versus $810.6 million in the same quarter a year earlier.

U.S. Airways Group Inc. (LCC: chart), airline services provider, said it swung to a fourth-quarter profit of $12 million in net income, or 13 cents per share, from a loss of $261 million, or $3.27 a share, in the year-earlier period. Excluding $74 million in special items, including $26 million in fuel-hedging losses, the airline operator said its net income would have been $86 million, to 91 cents per share. Revenue rose 8.8% to $2.79 billion from $2.56 billion in the same quarter a year earlier.