\subsection{STAR FORMATION}
Using star formation rates (SFR) measured in 500pc regions within the galaxy provided by collaborator Adam Leroy, we calculated the average SFR for each GMA in our catalog. We then calculated the molecular interstellar medium (ISM) depletion time, $\tau_\mathrm{H2}$, which is the time needed to convert all of the region's gas into stars. Fig.~\ref{tdep1} and Fig.~\ref{tdep2} show $\tau_\mathrm{H2}$ as a function of GMA surface density and velocity dispersion on a 1pc scale, respectively.  $\tau_\mathrm{H2}$ decreases with increasing $\Sigma$ and $\sigma_0$. From Table.~\ref{tdep_means}, which presents the geometric mean and standard error of $\tau_\mathrm{H2}$, we see that the ISM depletion time is much shorter for nuclear clouds than for disk clouds, and slightly lower for arm clouds than for inter-arm clouds. This all makes physical sense as turbulent clouds have more efficient star formation because the turbulence forces more of the cloud to high densities where gravity can dominate. 


