Today on Boston Public Radio: Medical ethicist Art Caplan talked about news of a promising COVID-19 vaccine from Cambridge-based Moderna Therapeutics, and his prescient writing in 2016 on "The End of Civilization and the Real Donald Trump.” MIT economist Jon Gruber talked about President Trump’s attempts to limit immigration during the COVID-19 pandemic, and highlighted all the ways that immigrants fuel the U.S. economy.  CNN analyst Juliette Kayyem talked about the surge of COVID-19 across the U.S., and the ongoing question of how to safely reopen schools.  Mass. Sen. Sonia Chang-Diaz broke down a new police reform bill, which passed in the state Senate early Tuesday morning. In light of tax day, we opened lines to ask listeners: has the COVID-19 pandemic made you more or less likely to skirt the rules when filing?  Journalist and naturalist Sy Montgomery called in to talk about the reopening of the New England Aquarium, and how to tell if your dog is suffering from heat stroke.