Isotope geochemistry this reason, enrichments are typically reported in "per mil" (‰, parts per thousand). These enrichments (δ) represent the ratio of heavy isotope to light isotope in the sample over the ratio of a standard. That is, Hydrogen isotope biogeochemistry Carbon has two stable isotopes, C and C, and one radioactive isotope, C. The stable carbon isotope ratio, "δ"C, is measured against Vienna Pee Dee Belemnite (VPDB). The stable carbon isotopes are fractionated primarily by photosynthesis (Faure, 2004). The C/C ratio is also an indicator of paleoclimate: a change in the ratio in the remains of plants indicates a change in
Tritium radioluminescence vials so that the flashlight can be easily located in the dark. Tritium is used to illuminate the iron sights of some small arms. The reticle on the SA80's optical SUSAT sight as well as the LPS 4x6° TIP2 telescopic sight of a PSL rifle, contains a small amount of tritium for the same effect as an example of tritium use on a rifle sight. The electrons emitted by the radioactive decay of the tritium cause phosphor to glow, thus providing a long-lasting (several years) and non-battery-powered firearms sight that is visible in dim lighting conditions. The tritium glow is