Classical unified field theories a survey of classical relativistic field theories of gravitation that have been motivated by theoretical concerns other than unification, see Classical theories of gravitation. For a survey of current work toward creating a quantum theory of gravitation, see quantum gravity. The early attempts at creating a unified field theory began with the Riemannian geometry of general relativity, and attempted to incorporate electromagnetic fields into a more general geometry, since ordinary Riemannian geometry seemed incapable of expressing the properties of the electromagnetic field. Einstein was not alone in his attempts to unify electromagnetism and gravity; a large number of mathematicians and
Pasadena Unified School District Pasadena Unified School District The Pasadena Unified School District is a unified school district that is responsible for the schools of Pasadena, California. , it has four high schools, five middle schools, three K–8 schools and 15 K–5 elementary schools. The number of elementary schools was reduced from 18 at the end of the 2010–11 school year. The district also serves the city of Sierra Madre and the unincorporated community of Altadena. PUSD is run by a board of education, whose members serve four-year terms. Duties of the board include budgeting, approving expenditures, establishing policy, making employment decisions, approving textbooks