Shelving according to the NRules
  When a weak photon decay competes with a strong photon decay in a 3-level atom, the weak occasionally prevails over the strong photon. This is the shelving phenomenon. It is assumed in this paper to occur objectively and autonomously, independent of external observation or lack of observation.   We here consider an auxiliary rule-set called the nRules that triggers a non-unitary mechanism that applies to all macroscopic measurements, as well as to many microscopic processes including shelving. These rules are shown below to describe the shelving process in complete detail without resorting to the notion of null measurement, or to an external measurement of any kind. They describe the V and the Lambda shelving configurations, as well as the two cascade configurations. 
Richard A Mould