  We study fluctuations in diffusion-limited reaction systems driven out of
their stationary state. Using a numerically exact method, we investigate
fluctuation ratios in various systems which differ by their level of violation
of microscopic time reversibility. Studying a quantity that for an equilibrium
system is related to the work done to the system, we observe that under certain
conditions oscillations appear on top of an exponential behavior of transient
fluctuation ratios. We argue that these oscillations encode properties of the
probability currents in state space.
