Roentgen (unit) capped at 3 MeV in 1950. The USSR all-union committee of standards (GOST) had meanwhile adopted a significantly different definition of the roentgen in 1934. GOST standard 7623 defined it as "the physical dose of X-rays which produces charges each of one electrostatic unit in magnitude per cm of irradiated volume in air at 0 °C and normal atmospheric pressure when ionization is complete." The distinction of physical dose from dose caused confusion, some of which may have led Cantrill and Parker report that the roentgen had become shorthand for 83 ergs per gram (0.0083 Gy) of tissue. They named
Wilhelm Barthlott (Geodiversity), including migration and globalization. His Biodiversity Distribution Map has been published in numerous textbooks in addition to being the foundation for many postgraduate studies. In the framework of the BMBF-BIOTA-AFRICA project led by him, biodiversity patterns in Africa as a model continent are analyzed and potential impacts of climate change are investigated. Wilhelm Barthlott was the first botanist to use high resolution in scanning electron microscopy systematically in the research of biological surfaces since 1970. Most prominent among his results was the discovery of the self-cleaning effect of superhydrophobic micro- and nanostructured surfaces, which were technically realized with the