NEW YORK—Optimism among U.S. manufacturers regarding the global economic outlook reached the highest level since the first quarter of 2012, according to the latest Manufacturing Barometer from PwC.  In the third quarter of 2013, 40 percent of respondents expressed optimism regarding the world economy for the next 12 months, up from 31 percent in the prior quarter and 29 percent from the third quarter of 2012. MORE