By DANIEL WAGNER

Associated Press

U.S. stocks opened mixed Monday after encouraging signs about the manufacturing sector, a key driver of economic growth.

The government said before trading began that orders for long-lasting goods rose in December by 4.6 percent, helped by a 10 percent gain in orders for new aircraft.

Heavy equipment maker Caterpillar said separately that its fourth-quarter net income exceeded analysts' expectations, after adjusting for the cost of a soured deal to buy a Chinese maker of roofing supports for mines. Caterpillar said it took a big charge in the quarter because the Chinese company had misrepresented its finances.

Caterpillar also announced guidance for 2013 that was consistent with Wall Street's expectations. The company expects growth in China to improve without regaining the levels seen in 2010 or 2011. The stock led the Dow Jones industrial average higher, gaining $2.25, or 2.3 percent, to $97.83 in the first 20 minutes of trading.

The Dow rose seven points to 13,903. The Standard & Poor's 500 index fell two to 1,501. The Nasdaq composite average rose seven to 3,156.

Among companies in the S&P 500 that reported earnings Monday, Biogen Idec Inc. said its fourth-quarter net income slipped nearly 3 percent because of a tax charge and higher expenses. Still, the biotech drug maker was one of the top gainers in the S&P 500, rising $4.26, or 2.9 percent, to $150.46.

Roper Industries Inc., which makes medical and industrial equipment, said its fourth-quarter net income rose 18 percent. But the company issued mixed guidance for the current quarter and full year 2013. It rose 53 cents to $119.36.

Strong corporate earnings have pushed stocks higher in the past two weeks after several calm, relatively news-free weeks. On Friday, the S&P 500 closed above 1,500 for the first time since December 2007, the official start of the worst economic downturn since the 1930s.

In addition to strong earnings, traders have been encouraged by signals that housing market is improving steadily and hiring is picking up, albeit slowly.

There will plenty of fresh data to drive trading this week, including retail sales, economic growth and the government's report on hiring and employment in January, which is due out Friday. More than one-fifth of the companies in the S&P 500 will report fourth-quarter earnings this week.

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Daniel Wagner can be reached at www.twitter.com/wagnerreports .

Copyright 2013 The Associated Press.