Small-cap stocks pulled upward with the rest of the market Tuesday amid climbing names like Simulations Plus ( SLP), which jumped 13% on positive results for the quarter ended May 31.

The Lancaster, Calif., company, which makes software for pharmaceutical research and education, posted a profit of $782,000, or 9 cents a share -- 4 cents higher per share than last year -- on revenue that leapt 47.1% to $2.6 million. The analyst who follows the company was looking for just 7 cents a share on sales of $2.3 million, as per Thomson Financial. Shares closed up $1.30 at $11.30.

Oil-and-gas driller Penn Virginia ( PVA) was also in the green after closing two property acquisitions valued together at $32.5 million. One, located in east Texas, contains estimated proved reserves of 19.5 billion cubic feet of natural gas equivalent; the other, in Mississippi, has 11.2 Bcfe. Penn has a roughly 76% average net revenue interest in the former property, and about 80% in the latter.

Shares of the company finished up 3.5% to $42.03 in support of both the Russell 2000, up 0.4% to 848.20, and the S&P SmallCap 600, which added 0.2% to 438.60.

On the other hand, HandHeld Entertainment ( ZVUE), maker of Zvue handheld media players, plunged more than 22% in heavy trading after issuing some $1.4 million in unsecured bonds. The proceeds will go to future acquisitions and general working capital purposes. Shares of the San Francisco company closed down 58 cents at $2.

China Sunergy ( CSUN) slid 19.3% to $11.28 after the solar-power company said a "relatively tight supply of polysilicon" in China has been driving up wafer prices, resulting in "increased pressure" on the company's margins.

Airspan Networks ( AIRN), a Florida-based purveyor of broadband fixed-wireless-access equipment, among other things, sank 11.1% on an announced slowdown in second-quarter revenue growth. Preliminary estimates have sales at roughly $22.5 million, or a sequential decline of 15.7%. The Street is seeking $29.5 million. Shares ended at $3.27.

Elsewhere, U.S. Energy Systems ( USEY) gave up 8.2% to $1.67 after sacking Chief Executive Asher Fogel, along with Executive VP Adam Greene, saying the board deemed "new senior leadership ... in the best interests of the company and its stockholders." For now, Fogel remains on the board, which said it's "working expeditiously" to find an adequate interim replacement for the CEO position.