The duties of the White House chief of staff vary greatly from one administration to another and, in fact, there is no legal requirement that the president even fill the position. However, since at least 1979, all presidents have found the need for a chief of staff, who typically oversees the actions of the White House staff, manages the president's schedule, and decides who is allowed to meet with the president.
Sad loss: Fresh Prince of Bel Air star James Avery has died aged 65. Avery's official cause of death is listed as cardiorespiratory arrest, which means his heart stopped. The site also reported he was cremated and his ashes were scattered at sea off the coast of Los Angeles.
Avery and his colleagues showed that DNA was the key component of Griffith's experiment, in which mice are injected with dead bacteria of one strain and live bacteria of another, and develop an infection of the dead strain's type.riffith's experiment, reported in 1928, identified that some transforming principle in pneumococcal bacteria could transform them from one type to another. Griffith, a British medical officer, had spent years applying serological typing to cases of pneumonia, a frequently fatal disease in the early 20th century.