Monday's Small-Cap Winners and Losers

Aeroflex (ARXX Quote) surged 19% on news of a $1 billion buyout by General Atlantic and Francisco Partners. Shareholders of the Plainview, N.Y., microelectrics firm will get $13.50 a share in cash, a 22.6% premium to Friday's closing price. Shares rose $2.13 to $13.14.

Pathmark (PTMK Quote) rose 10% after the New Jersey-based supermarket chain set plans to sell itself to A&P (GAP Quote) for about $1.3 billion in cash and stock. The deal should close between September 2007 and February 2008. Pathmark was jumping $1.12 to $12.37, while A&P was adding 92 cents, or 3%, to $31.78.

Gastar Exploration (GST Quote) rose 14% after saying work was finished on an East Texas gas well in which it has a 50% postcompletion working interest. The initial gross daily flow rate is about 12 million cubic feet, says the Houston-based company. Shares were rising 21 cents to $1.71.

Myriad Genetics (MYGN Quote) gained 7% after Flurizan, its treatment for mild Alzheimer's disease, yielded what it called highly statistically significant results in a two-year midphase study. Shares of Salt Lake City-based Myriad were up $2.23 to $33.46.

Memory Pharma (MEMY Quote) lost nearly a third of its value after its Mem 1003 drug failed to reduce acute mania in individuals with bipolar disorder. Shares of the Montvale, N.J., company were off 97 cents to $2.16.