Updated from 11:46 a.m.

Shares of Engineered Support Systems ( EASI) were among the Nasdaq's losers Wednesday, falling 10.6% after the company posted second-quarter earnings that fell below expectations and cut its full-year view for earnings.

The defense contractor posted continuing earnings of $20.1 million, or 46 cents a share, on sales of $263.8 million. Analysts polled by Thomson First Call were expecting earnings of 53 cents a share on sales of $250.1 million. A year ago the company earned $18.3 million, or 44 cents a share, on sales of $210.1 million.

Looking ahead, Engineered Support now expects full-year earnings of $2 to $2.03 a share, down from earlier guidance of $2.09 to $2.12 a share. Sales, meanwhile, are now expected to be between $1.02 billion to $1.05 billion, up from previous guidance of $990 million to $1 billion. Analysts had been expecting earnings of $2.17 a share on sales of $1.03 billion. Shares traded down $4.15 to $34.85.

School Specialty ( SCHS) rose 19.8% after the company agreed to be acquired by an affiliate of private equity firm Bain Capital Partners for about $1.5 billion. Shareholders of School Specialty will receive $49 a share in cash, which represents a 25% premium over Tuesday's closing price of $39.22. The Bain affiliate will also assume about $101 million in debt. Chief executive David Vander Zanden is expected to remain in his current role with the education company after the transaction. The transaction is expected to close during School Specialty's second fiscal quarter, which ends Oct. 29. Shares traded up $7.78 to $47.

Shares of Terex ( TEX) rose 9.2% after the company posted first-quarter earnings that were easily ahead of expectations. The maker of construction vehicles and mining equipment earned $30.3 million, or 59 cents a share, on sales of $1.45 billion. Excluding items, the company would have earned $30.8 million, or 60 cents a share. Analysts were expecting earnings of 51 cents a share. A single analyst was expecting sales of $1.2 billion. A year ago the company earned $17 million, or 34 cents a share, on sales of $1.04 billion. Looking ahead, Terex expects full-year earnings of $3.50 to $3.70 a share. Analysts are expecting earnings of $3.50 a share. Shares traded up $3.64 to $43.16.

Westaff ( WSTF) fell 11% after the company swung to a second-quarter loss. The staffing services company reported a loss of $400,000, or 2 cents a share, on sales of $138.3 million. A year ago the company earned $200,000, or 1 cent a share, on sales of $131.3 million. Gross margin rose to 17.3% during the quarter from 16.9% a year ago. Shares traded down 38 cents to $3.09.

Shares of Daktronics ( DAKT) fell 6.4% after the maker of electronic scoreboards posted fourth-quarter earnings that fell below expectations. The company earned $3 million, or 15 cents a share, on sales of $61.3 million. Analysts were expecting earnings of 23 cents a share on sales of $63.1 million. A year ago the company earned $4.1 million, or 21 cents a share, on sales of $57.9 million. Looking ahead, Daktronics forecast first-quarter earnings of 22 cents to 32 cents a share. Analysts are expecting earnings of 24 cents a share. For the full year, the company expects sales growth in excess of 15%. Shares traded down $1.49 to $21.80.

NYSE volume leaders included Nortel Networks ( NT), up 20 cents to $2.79; Lucent Technologies ( LU), unchanged at $2.81; Time Warner ( TWX), up 9 cents to $17.49; Corning ( GLW), up 56 cents to $16.24; and General Electric ( GE), up 45 cents to $36.93.

Nasdaq volume leaders included Intel ( INTC), up 37 cents to $27.33; Microsoft ( MSFT), up 4 cents to $25.84; Cisco Systems ( CSCO), up 23 cents to $19.63; Google ( GOOG), up $9.96 to $287.23; Oracle ( ORCL), up 9 cents to $12.89; and Sun Microsystems ( SUNW), up 12 cents to $3.93.