Twin Cities Public Television's foray into nightly local news coverage appears to be all but over. Sources say Newsnight Minnesota- TPT's half-hour long evening news program launched in 1994 - is on the chopping block. TPT officials won't confirm Newsnight faces a shutdown. But a spokeswoman says the station is considering a number of cutback options because of the enormous costs of meeting a federal mandate to convert to digital transmission. TPT staffers say they've been informed Newsnight's future is in serious doubt and the show's staff members have started looking for other jobs. The board is expected to make a final decision on Newsnight's future next month. Brian Lambert is Media Critic at the St. Paul Pioneer Press. He says for the most part, Newsnight has lived up to its promise to provide a more thoughtful alternative to commercial t-v news: