Persian cat since the early 1990s and the Persian lost its top spot to the British Shorthair in 2001. As of 2012, it was the 6th most popular breed, behind the British Shorthair, Ragdoll, Siamese, Maine Coon and Burmese. In France, the Persian is the only breed whose registration declined between 2003 and 2007, dropping by more than a quarter. The most color popular varieties according to CFA registration data are seal point, blue point, flame point and tortie point Himalayan, followed by black-white, shaded silvers and calico. The breed standards of various cat fancier organizations may treat the Himalayan and Exotic
Point source source decreases in proportion to the inverse square of the distance from the source, if the distribution is isotropic, and there is no absorption or other loss. In mathematics, a point source is a singularity from which flux or flow is emanating. Although singularities such as this do not exist in the observable universe, mathematical point sources are often used as approximations to reality in physics and other fields. Generally, a source of light can be considered a point source if the resolution of the imaging instrument is too low to resolve the source's apparent size. There are two types