deletions | additions       diff --git a/Payam.tex b/Payam.tex  index e149ab6..3a1a67e 100644  --- a/Payam.tex  +++ b/Payam.tex 
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\begin{itemize}  \item The two $t_{\rm h}$s are measuring different things. Payam's $t_{\rm h}$ is considering the {\it diffusion }of a particle's momentum: the characteristic time in the velocity autocorrelation. My $t_{\rm h}$ is about information flow via sonic waves: this is much smaller than the vorticity time-scale.  \item {\it What should the time-scale be from physical reasoning?\\   What reasoning: what  is the physics behind establishing the flow profile $\vec{v}(\vec{x})$ in the fluid around the DNA? (Read \citet{Broman_Rudenko_2010}).\\ And which process (sound or vorticity) carries more momentum?}  \item Another thing to consider: {\it does it even matter?} The time-scale they use is larger than the sound-time, and places a more stringent test on the steady-state assumption. So my objection would only strengthen the conclusion. The vorticity moves slowest, and the fluid velocity profile might only assume the anticipated form once this final piece has arrived to distance $\ell$ from the DNA.