Sundial's guests for Wednesday, April 18: Cuba's Raul Castro stepped down and the new leader of the communist island is Miguel Diaz-Canel . WLRN's Tim Padgett discusses what the new president means for U.S.-Cuba relations. Aileen Marty is a chemical weapons expert as well as a leading authority on contagious diseases. She shares her thoughts on the chemical weapons attack in Syria and her memory of investigating the Ebola epidemic from 2013 to 2016. The city of Miami and Miami-Dade County are