Post-concussion syndrome. Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that may continue for weeks, months, or a year or more after a concussion â a mild form of traumatic brain injury (TBI).
The Equatorial (Celestial) Coordinate System. Equatorial coordinates, also called simply celestial coordinates, are the standard coordinate system for the sky. It is meant for the fixed sphere of the stars within which the Earth and Sun move.
The coordinates start from the equator projected onto the sphere and a celestial coordinate system starting with up and down based on degrees north or south of the equator, and left and right based on degrees east or west of the vernal equinox. Earth within celestial sphere by Tfr000 29 March 2012 - Own work.