Among the stock activity stories for Friday, Sept. 4, from AP Financial News:

NEW YORK (AP) ¿ Shares of Bridgepoint Education Inc. dropped Friday, a day after the company said it expects a federal audit to result in proposed fines and "corrective action."

HARTFORD, Conn. (AP) ¿ Shares of Esterline Technologies Corp. surged Friday, a day after the aerospace and defense contractor posted strong third-quarter earnings and raised its 2009 guidance.

NEW YORK (AP) ¿ Shares of Micrus Endovascular Corp. rose Friday after an analyst began covering the medical device maker with an "outperform" rating.

PHILADELPHIA (AP) ¿ Shares of Ciena Corp. moved higher on Friday after an analyst raised his earnings and revenue forecast for the company due to better cost controls and growing interest for its Ethernet products.

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