which suggests the FRB dispersions are quantised to a standard unit. A lot of newsies picked this up last week and suggested it was proof of... something unusual.
The authors think it suggests the opposite.
Given the date, I can't tell if the paper is serious or not. But if it's meant to be serious, the effect seems real - possibly an artefact of a very small sample size, but it's hard to tell.
It would be useful to have access to the raw data to see the exact dispersion shape and frequency range, to check whether it matches - say - any standard radar chirp signal.
http://en.wikipedia.org/wiki/PSR_B1919%2B21