Most commercial flights, however, fly at 38,000 feet above the Class B maximum height and there is not a specific speed limit imposed. BA Captain Dave Thomas stated why they fly at this height: 'This sort of altitude is a good compromise between engine efficiency and aerodynamic efficiency for jet aircraft.
The most common cause of de Quervainâs tenosynovitis is chronic overuse of the wrist. Repetitive movements day after day cause irritation and pain. One common movement that causes it is lifting a child into a car seat. Another is lifting heavy grocery bags by the handles.
Causes. Prader-Willi syndrome is a genetic disorder, a condition caused by an error in one or more genes. Although the exact genes responsible for Prader-Willi syndrome haven't been identified, the problem lies in a particular region of chromosome 15.rader-Willi syndrome disrupts the normal functions of a portion of the brain called the hypothalamus. The hypothalamus controls hunger and thirst and releases hormones that prompt the release of other substances responsible for growth and sexual development.