Updated from Oct. 3Investors started the fourth quarter with the same lack of conviction that has characterized the market all year. After posting early gains Monday, stocks were pressured following a report confirming the Federal Reserve's prediction that even after Hurricane Katrina, inflation risks appear to be outweighing the chance that economic growth will be impaired. The markets reflected this no so rosy but not completely bearish outlook. Government bonds fell, but stocks ended mixed as the Nasdaq Composite advanced slightly. The Institute for Supply Management said its manufacturing index jumped to 59.4 in September from 53.6 in August. That was well above expectations for the index to dip to 52.0. One key inflation guage in the ISM report was particularly notable: The survey's prices-paid index skyrocketed to 78 from 62.5. "