#perturbation__disturbance  activity that is an intrusion or interruption; "he looked around for the source of the disturbance"; "there was a disturbance of neural function"
  supertype:  #activity  any specific activity or pursuit; "they avoided all recreational activity"
  subtype:  #fuss__trouble__hassle  an angry disturbance; "he didn't want to make a fuss"; "they had labor trouble"; "a spot of bother"
  subtype:  #magnetic_storm  a sudden disturbance of the earth's magnetic field; caused by emission of particles from the sun

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