Delayed gamma emissions are the most common form of delayed radiation, but are not the only form. It is common for the short-lived isotopes to have delayed emissions of various particles. In these cases, it is commonly called a beta-delayed emission. This is because the decay is delayed until a beta decay takes place. For instance, nitrogen-17 emits two beta-delayed neutrons after its primary beta emission. Just as in the above delayed gamma emission, the nitrogen is not the actual source of the neutrons, the source of the neurons is a short-lived isotope of oxygen.