This week, we chat about why grizzly bears seem to be dying on Canadian railway tracks, slow-release fertilizers that reduce environmental damage, and cleaning water with the power of the sun on the cheap, with Online News Editor David Grimm. And David Malakoff joins Alexa Billow to discuss a package of stories on the role of science and evidence in policymaking[link TK]. Listen to previous podcasts.  [Image: tacky_ch/iStockphoto; Music: Jeffrey Cook]