Steroids and other medications. Long-term use of oral or injected corticosteroid medications, such as prednisone and cortisone, interferes with the bone-rebuilding process. Osteoporosis has also been associated with medications used to combat or prevent: Seizures; Gastric reflux; Cancer; Transplant rejection; Medical conditions
The main functions of using a compass are: 1  tell which direction you are traveling - your heading. 2  tell which direction an object is from you - its bearing. 3  keep you following a straight line of travel. 4  orient a map - aligning a map with the actual land.  triangulation - determining your location with a map.
On small vessels the compass is usually located in front of the helm position. Care should be taken to ensure the compass is installed far enough away from structural members, equipment and instruments such as radios, speakers, engine rev counters (tachometers), etc, which can produce strong magnetic fields.