An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmuted into another element through a nuclear reaction.
Almost 40 years separate Shirley Ann Jackson's achievement, as the first African-American woman to earn a Ph.D. in theoretical high energy physics at Massachusetts Institute of Technology, and Jedidah Isler, the first African-American woman to receive a Ph.D. in Astrophysics from Yale.
Maryam Mirzakhani: 'The more I spent time on maths, the more excited I got'. Maryam Mirzakhani has become the first woman to win the Fields Medal, the most prestigious prize in mathematics. Mirzakhani, 37, is of Iranian descent and completed her PhD at Harvard in 2004. Her thesis showed how to compute the Weil-Petersson volumes of moduli spaces of bordered Riemann surfaces.