A small liberal arts college on the north shore of Lake Tahoe will stay alive by partnering with two for-profit firms. Knowledge Universe Learning Group and Cardean Learning Group will give Sierra Nevada College $15 million over the next five to seven years, the college announced yesterday. The companies also will help the college develop online learning software. Both companies are affiliated with Wall Street junk bond trader Michael Milken, the AP reports. Trustees at the college began investigating partnerships when they realized endowment funds alone could not help the school survive.