Residency is a stage of graduate medical training. A resident or house officer is a physician (holding either a M.D. , D.O. , MBBS, MBChB, BMed or D.P.M. degree) who practices medicine usually in a hospital or clinic.The definition of residency varies worldwide by country and structure of the medical industry.esidency is a stage of graduate medical training. A resident or house officer is a physician (holding either a M.D. , D.O. , MBBS, MBChB, BMed or D.P.M. degree) who practices medicine usually in a hospital or clinic.
In astronomy, the term period usually refers to how long an object takes to complete one cycle of revolution. In particular the orbital period of a star or planet is the time it takes to return to the same place in the orbit. Quasi-periodic oscillation. Jump to: navigation, search.
Astronomical twilight : Astronomical twilight is defined as the period when the sun lies between 18 and 12 degrees below the horizon. At this time, point light sources such as stars remain visible in the sky, but fainter objects such as nebulae and galaxies are no longer visible.