|
|
Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.
The U.S. Preventive Services Task Force recommends that all women age 65 years of age or older should be screened with bone densitometry.
Many medications that are used to treat infertility are injected subcutaneously. This is easy to do using the anterior abdomen as the site of injection but avoiding the area directly around the belly button.