DNA analysis from a genetic database finds nearly 42,000 living descendants of 27 African American furnace workers from the 18th and 19th century. Plus, efforts to replicate claims of a room-temperature superconductor fall short, and how to get the most out of remote conferences. DNA analysis from a genetic database finds nearly 42,000 living descendants of 27 African American furnace workers from the 18th and 19th century. Plus, efforts to replicate claims of a room-temperature superconductor fall short, and how to get the most out of remote conferences.