b'The Presidents CommentaryCelebrating Alumni AchievementsFor decades, Carnegies extraordinary reputation for transformational research has been strengthened by the great contributions made by our postdocs and research associates. During 12 their years at Carnegie, their talent, creativity, and intellectual rigor were fundamental to our work. As Carnegie alumni, their achievements extend our impact worldwide.In 2018, two of our exceptional postdoctoral alumni won major prizes for their great contributions to science. Professor Tasuku Honjo, who served as a postdoctoral fellow in the Brown Lab at the Department of Embryology from 1971 to 1973, shared the 2018 Nobel Prize in Physiology or Medicine for his discovery of a protein important to the immune systems ability to attack tumor cells. This discovery is fundamental to therapies that have been shown to be particularly effective in fighting cancer.Professor Sarah Stewart, a postdoc in the Geophysical Laboratory in 2002 and 2003, was named a MacArthur Fellow for her work in advancing new theories of how celestial collisions give birth to planets and their natural satellites. Stewart has proposed that the Earth and the Moon were formed by a synestiaa donut-like cloud of material produced by a high-energy, high-angular momentum collision of two bodies. It could explain why the Earth and Moon have similar chemical compositions and certain aspects of the Moons orbit.Tasuku Honjo was a postdoctoralSarah Stewart, former Geophysical Laboratory postdoctoral fellow from 2002 to 2003, was awarded fellow in the Brown Lab at thea 2018 prestigious MacArthur Fellowship for advancing new theories of how celestial collisions Department of Embryology fromgive birth to planets and their natural satellites, such as the Earth and Moon. Stewart is currently a 1971 to 1973. He shared the 2018professor in the Department of Earth and Planetary Sciences at U.C.-Davis. Nobel Prize in Physiology or MedicineImage courtesy MacArthur Foundation for the discovery of cancer therapy by inhibition of negative immune regulation. Image courtesy Wiki Commons'