Radio Profile Instability in the Millisecond Pulsar PSR J0437-4715 due   to Spiky Emission
  The instability in one of the components of the radio integrated profile (IP) of the millisecond pulsar PSr J0437-4715 is correlated with the occurrence of the spiky emission in that component. It is speculated that the instability in other components is also due to the spiky emission. This might have important implications for interpreting the individual components of the IP as independent beams or regions of emission. 
M. Vivekanand