Those rules can dramatically narrow the windows of time when prescribed fires can occur — sometimes to just one or two weeks a year. (dotearth.blogs.nytimes.com)
The detectors are struck regularly by cosmic rays, which can mimic the annihilation signal, so narrowing the window of time in which matter — antimatter annihilations should be taking place significantly reduces the background noise the physicists must sift through to identify genuine annihilation events. (scientificamerican.com)
However, Williams explained sweet corn trials are hand harvested, as opposed to being mechanically harvested, and during a very narrow window of time. (sciencedaily.com)