The world's two largest economies have been showing signs of improvement, but experts say the recession in Europe remains the biggest challenge to sustained global growth. In the United States, reports released Thursday showed gains in manufacturing, consumer confidence and private sector payrolls. Also on Thursday, U.S. automakers reported another month of improved car sales in October, even as Superstorm Sandy may have dampened month-end results.Factoring in a boost from construction spending and lower imports, the latest indicators suggest the U.S. economy may have grown at a slightly faster rate in the third ... (full story)