 By CHRISTIAN BERTHELSEN And CHRIS DIETERICH LONG-DISTANCE CALL: Economist Larry Summers, center, joins Nasdaq chief Robert Greifeld, to Mr. Summers's left, and financial news anchor Maria Bartiromo, in scarf, among others, while ringing the opening ... January rally interrupted as buyers pull backReuters Wall Street Stumbles Amid Mixed Earnings, DataFox Business US Stocks Fall After Dow Average GainsBloomberg |