Roentgen (unit) One roentgen deposits of absorbed dose in dry air, or in soft tissue. One roentgen of X-rays may deposit anywhere from in bone depending on the beam energy. This tissue-dependent conversion from kerma to absorbed dose is called the F-factor in radiotherapy contexts. The conversion depends on the ionizing energy of a reference medium, which is ambiguous in the latest NIST definition. The roentgen has its roots in the Villard unit defined in 1908 by the American Roentgen Ray Society as "the quantity of radiation which liberates by ionisation one esu of electricity per cm of air under normal conditions
The Invention of the Jewish People The Invention of the Jewish People The Invention of the Jewish People (, literally "When and How Was the Jewish People Invented?") is a study of the historiography of the Jewish people by Shlomo Sand, Professor of History at Tel Aviv University. It has generated a heated controversy. The book was in the best-seller list in Israel for nineteen weeks. An English translation of the book was published by Verso Books in October 2009. The book has also been translated into German, Italian, Spanish, Portuguese, Arabic, French and Russian, and as of late 2009 further translations were underway. "The Invention