Several women helped to perform the extensive calculations required for the design of the first nuclear bombs. Digital computers as we know them today did not exist early in World War II, and the majority of the earliest calculations were performed using electrically powered mechanical calculating machines. Naomi Livesay, (third from the left in photos) had a degree in mathematics and experience in using electric calculating machines in the analysis of survey data, starting her work at Los Alamos in 1944. In no time she was supervising a team that conducted calculations to track the blast wave of the conventional explosion through the fissile material at the core of the bomb and then to track the shock wave of the fission detonation back out. Because these calculations were so essential to this development phase, they were done under extreme time pressure, in 24-hour shifts, six days a week.