Strict regulations on diesel emissions that the California Air Resources Board approved in December 2008 are coming under renewed fire. At the time, members of the trucking industry and others complained that CARB was acting all Chicken Little and exaggerating how bad the diesel emissions were for human health. Since then, it turns out, one of the scientists involved in the study that detailed the negative health effects misrepresented his credentials. Instead of getting his Ph.D. in statistics from the University of California Davis, Hien Tran actually got a mail-order Ph.D. from a "university" based at a mailbox at a...