You may need a backup method of birth control if you have vaginal intercourse during the seven days after a missed pill. Some backup methods are the condom, female condom, diaphragm, or sponge. You can also use emergency contraception (morning after pill) up to five days after unprotected intercourse.
Strontium-90, a radioactive isotope, is a by-product of nuclear reactors and present in nuclear fallout. It has a half-life of 28 years. It is absorbed by bone tissue instead of calcium and can destroy bone marrow and cause cancer. However, it is also useful as it is one of the best high-energy beta-emitters known. It can be used to generate electricity for space vehicles, remote weather stations and navigation buoys.
Named for a city in Scotland, strontium is a relatively soft, silvery-yellow metal. Like other alkali-earth metals, strontium is chemically active, reactin Named for a city in Scotland, strontium is a relatively soft, silvery-yellow metal. Like other alkali-earth metals, strontium is chemically active, reacting with both air and water. It is more reactive than calcium or magnesium. Strontium is used in glass for color television tubes because it blocks radiation, and in fireworks and other pyrotechnics, where it imparts a red color.