Several Republican lawmakers are challenging the Obama administration's science czar over what they claim are repeat incidents of "scientific misconduct" among agencies, questioning whether officials who deal with everything from endangered species to nuclear waste are using "sound science." The letter sent Wednesday to John Holdren, director of the Office of Science and Technology Policy, cited four specific controversies in recent years where scientific findings were questioned. Sens. David Vitter, R-La., and James Inhofe, R-Okla., and Rep. Darrell Issa, R-Calif., rattled off a slew of questions on what they called "the apparent collapse in the quality of scientific work being...