Riverbed Technology ( RVBD) was down 6.86% after a UBS analyst reduced his target price for the stock to $24 from $34. The stock was at $19.41, off $1.43, in recent trading. Saud Masud, the analyst, said the company may see a falloff in project activity in the upcoming months. Advanced Micro Devices ( AMD) will report its earnings after the close of trading. Analysts have been critical of the chipmaker's performance in the PC market. Analysts polled by Thomson Financial expect AMD to lose 36 cents a share. The stock was down 25 cents, or 3.8%, to $6.32 in recent trading. Perini ( PCR) shares tumbled 26.9% to $27.56. The Framingham, Mass., construction company announced that the developer of its Cosmopolitan Resort & Casino project in Las Vegas defaulted on its $760 million construction loan Wednesday . Elsewhere, a study in the New England Journal of Medicine is taking a toll on makers of anti-depressants. An article concluded that published studies over-represent trials with positive results , potentially skewing perceptions of efficacy. "Not only were positive results more likely to be published, but studies that were not positive, in our opinion, were often published in a way that conveyed a positive outcome," wrote the authors of "Selective Publication of Antidepressant Trials and Its Influence on Apparent Efficacy." Published literature on 12 antidepressants suggested 94% of the studies on the drugs had positive outcomes, but in totality only 51% of the studies on the 12 drugs were thought to have positive results by the FDA. Some anti-depressant makers with drugs involved in the article's analysis traded down after the research was published both in post-market trading Wednesday and on Thursday. Wyeth ( WYE) was down $1.53, or 3.33%, at $44.61. Eli Lilly ( LLY) was down $1.19, or 2.1% at $54.88, GlaxoSmithKline ( GSK) was down 70 cents, or 1.4%, at $50.89, and Bristol Myers Squibb ( BMY) was down 63 cents, or 2.4%, at 25.19. Rising on an upbeat forecast was Warren, Ohio's Stoneridge ( SRI). The stock rose 32.4% to $9.39 after the manufacturer of electrical components for trucks and farm machinery guided for fourth-quarter 2007 earnings per share between 24 cents and 30 cents and full-year EPS of 67 cents to 73 cents. Previous 2007 guidance was for 45 cents to 55 cents a share. ZymoGenetics ( ZGEN) shares added $2.01, or 16.9%, to $13.98 after it got the delayed FDA approval for rThrombin, or Recothrom. The product is a plasma-free thrombin, used as a blood clotting agent when control of bleeding by standard surgical techniques is ineffective or impractical. ZymoGenetics signed a collaboration with Bayer HealthCare Pharmaceuticals in June worth up to $198, and the approval triggers a $40 million milestone payment. The stock made "Winners and Losers" on Wednesday when it dipped after an analyst initiated a sell rating, questioning whether the drug would get approved without further delay.