Conductor Valery Gergiev will lead the renowned Kirov Orchestra in a pair of concerts this week at UNC's Memorial Hall. Tuesday at 7:30 p.m. the orchestra will perform works by Prokofiev and Tchaikovsy. Wednesday's concert, also at 7:30 p.m., will feature works by Prokofiev and Beethoven. Tickets are available at carolinaperformingarts.org, by calling 843-3333 or at the Memorial Hall Box Office on Cameron Avenue.