Roentgen (unit) this derivative quantity the roentgen equivalent physical (rep) to distinguish it from the ICR roentgen. The introduction of the roentgen measurement unit, which relied upon measuring the ionisation of air, replaced earlier less accurate practices that relied on timed exposure, film exposure, or fluorescence. This led the way to setting exposure limits,and the National Council on Radiation Protection and Measurements of the United States established the first formal dose limit in 1931 as 0.1 roentgen per day. The International X-ray and Radium Protection Committee, now known as the International Commission on Radiological Protection (ICRP) soon followed with a limit of
Sanford Burnham Prebys Medical Discovery Institute careers in basic and translational research through a curriculum of focused, multi-disciplinary instruction. In 2015, SBP achieved accreditation with the Western Association of Schools and Colleges. SBP also employs postdoctoral fellows; there are typically around 250 postdocs training at SBP at any time. The endowment was recorded at as low as $15.2 million, a 13 percent drop from nearly $17.5 million in February 2008, due largely to losses on investments. Its endowment stood at $22.5 million as of Dec. 31, 2009. Sanford Burnham Prebys Medical Discovery Institute Sanford Burnham Prebys Medical Discovery Institute (SBP) is a non-profit medical research institute