Chick Hearn would have called it nervous time. Wall Street remains jittery about whether the subprime tumult might spill over to the rest of the market. In this climate, statistics confirming what everybody pretty much knew already have a way taking center stage. Thus comes word that mortgage-delinquency rates jumped in the fourth quarter. Delinquency rates have been going up for months now (and fourth-quarter delinquencies are often high because of home-heating bills and Christmas presents), but even in context the numbers ain't great. And of course, there's the mess at Irvine-based New Century Financial, which is on the verge of filing for bankruptcy. There are some other freelance worries - not to mention some more profit taking -but the subprime stuff appears to be the big story. The Dow is down 178 points with a little over an hour to go.