Stocks of the Valley 50 index gained 3.1 percent during the two weeks ended Sept. 11. The uptick was in step with the broader stock market, which rallied as the U.S. military re-evaluated its strategy on action in Syria. Among the Valley 50, the biggest gainer was Kythera Biopharmaceuticals, an experimental drug company that reported a stronger cash position after a payment from Bayer AG. Shares jumped 24 percent. Ryland Group Inc. increased 11 percent after opening two new developments in Minnesota. The biggest loser was Tix Corp., down nearly 13 percent.