Deme U maintained a population of 8130 until there was a shift 1127.8687 generations ago that grew its numbers to 8523, a figure that has remained the same since.
time_units: generations
demes:
  - name: U
    start_time: .inf
    epochs:
      - start_size: 8130
        end_time: 1127.8687
      - start_size: 8523
        end_time: 0