United and American Science jump, Werner and Impax slump

NEW YORK, N.Y. – Stocks that moved substantially or traded heavily on Tuesday:

United Continental Holdings Inc., up $1.46 to $44.86

The parent of United Airlines detailed plans to increase revenue, control costs and improve reliability in a bid to win back disgruntled travellers.

American Science & Engineering Inc., up $4.54 to $36.88

The X-ray inspection systems maker agreed to be acquired by airport security and full-body scanner manufacturer OSI Systems.

Canadian Pacific Railway Ltd., down $3.09 to $124.34

The railroad said it expects its profit and revenue to fall in the second quarter because of reduced commodity shipments.

Impax Laboratories Inc., down $3.66 to $28.31

The generic drugmaker said it will pay $586 million to buy drugs owned by Allergan and Teva Pharmaceutical Industries.

Werner Enterprises Inc., down $2.37 to $22.31

The transportation and logistics company forecast disappointing second-quarter results due to sluggish freight market conditions.

Imperva Inc., up $5.02 to $45.46

Elliott Capital, activist investor Paul Singer’s fund, disclosed a stake in data security software company.

CarMax Inc., down $2.49 to $48.14

The used-car dealership reported disappointing first-quarter results as its costs increased and sales fell short of Wall Street estimates.

AT&T Inc., up 29 cents to $41.07

Phone company stocks traded higher Tuesday as investors got a bit more cautious following the market’s jump a day ago.