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.
While natural strontium is stable, the synthetic 90Sr isotope is present in radioactive fallout and has a half-life of 28.90 years.0Sr has been used as a power source for radioisotope thermoelectric generators (RTGs). 90 Sr produces approximately 0.93 watts of heat per gram (it is lower for the form of 90 Sr used in RTGs, which is strontium fluoride).