protected void updatePersonnel(int numUpdates) {
    if (numUpdates % REFRESH_INTERVAL == 0) {
      final Base base = employs.base() ;
      //
      //  Clear out the office for anyone dead-
      for (Actor a : workers  ) if (a.destroyed()) setWorker(a, false) ;
      for (Actor a : residents) if (a.destroyed()) setResident(a, false) ;
      //
      //  If there's an unfilled opening, look for someone to fill it.
      //  TODO:  This should really be handled more from the Commerce class?
      if (employs.careers() == null) return ;

      for (Background v : employs.careers()) {
        final int numOpenings = employs.numOpenings(v) ;
        if (numOpenings > 0) {
          if (GameSettings.hireFree) {
            final Human citizen = new Human(v, employs.base()) ;
            citizen.mind.setWork(employs) ;
            final Boardable t = employs.canBoard(null)[0] ;
            citizen.enterWorldAt(t, base.world) ;
          }
          else {
            base.commerce.incDemand(v, numOpenings, REFRESH_INTERVAL) ;
          }
        }
      }
    }
  }