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.
First Woman Is Appointed As Dean of Harvard Law. Elena Kagan, a former White House aide to President Bill Clinton and onetime clerk to Justice Thurgood Marshall of the Supreme Court, has been appointed dean of the Harvard University Law School, Lawrence H. Summers, the university president, announced yesterday. Ms. Kagan, 42, will be the first woman to lead the law school in its 186-year history.