enrollment of recipients of the National Merit $2,500 Scholarship (132 scholars). Twenty-seven percent of admitted students receive federal Pell grants. Discoveries and innovation A number of significant inventions and discoveries have been made by Berkeley faculty members and researchers: Natural sciences Atomic bomb – Physics professor J. Robert Oppenheimer was wartime director of Los Alamos National Laboratory and the Manhattan Project. Carbon 14 and photosynthesis – Martin Kamen and Sam Ruben first discovered carbon 14 in 1940, and Nobel laureate Melvin Calvin and his colleagues used carbon 14 as a molecular tracer to reveal the carbon assimilation path in photosynthesis, known as Calvin cycle. Carcinogens – Identified chemicals that damage DNA. The Ames test was described in a series of papers in 1973 by Bruce Ames and his group at the university. Chemical elements – 16 elements have been discovered at Berkeley (technetium, astatine, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, lawrencium, rutherfordium, dubnium, and seaborgium). Covalent bond – Gilbert N. Lewis in 1916 described the sharing of electron pairs between atoms, and invented the Lewis notation to describe the mechanisms. CRISPR gene editing – Nobel laureate Jennifer Doudna discovers a precise and inexpensive way for manipulating DNA in human cells. Cyclotron – Ernest O. Lawrence created a particle accelerator in 1934, and was awarded the Nobel Physics Prize in 1939. Dark energy – Saul Perlmutter and many others in the Supernova Cosmology Project discover the universe is expanding because of dark energy 1998. Flu vaccine – Wendell M. Stanley and colleagues discovered the vaccine in the 1940s. Hydrogen bomb – Edward Teller, the father of hydrogen bomb, was a professor at Berkeley and a researcher at the Lawrence Livermore National Laboratory and the Los Alamos National Laboratory. Immunotherapy of cancer – James P. Allison discovers and develops monoclonal antibody therapy that uses the immune system to combat cancer 1992–1995. Molecular clock – Allan Wilson discovery in 1967. Neuroplasticity – Marian Diamond discovers structural, biochemical, and synaptic changes in brain caused by environmental enrichment 1964 Oncogene – Peter Duesberg discovers first cancer causing gene in a virus 1970s. Telomerase – Elizabeth H. Blackburn, Carol Greider, and Jack Szostak discover enzyme that promotes cell division and growth 1985. Vitamin E – Gladys Anderson Emerson isolates Vitamin E in a pure form in 1952. Computer and applied sciences Berkeley RISC – David Patterson leads ARPA's VLSI project of microprocessor