deletions | additions       diff --git a/results_table.tex b/results_table.tex  index 6c1d5d0..7fd0af5 100644  --- a/results_table.tex  +++ b/results_table.tex 
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\[  \rho c = \sqrt{\frac{\sum dP^2}{\sum dU^2}}  \]  where the sums are taken over an integral number of cardiac periods. This relationship was derived by minimising the magnitude of the backward waves over the cardiac period, but was subsequently shown to be strictly valid only if the correlation between $dP_+$ and $dP_-$ was is  zero [Moto Sugawara, personal communication??] The derivation of this result is instructive and can be described briefly. Assume that the measured changes in $P$ and $U$ are the sum of a forward and a backward contribution  \[