deletions | additions       diff --git a/In_cite_streitburger2014impact_the_researchers__.tex b/In_cite_streitburger2014impact_the_researchers__.tex  index 78ead51..24f2642 100644  --- a/In_cite_streitburger2014impact_the_researchers__.tex  +++ b/In_cite_streitburger2014impact_the_researchers__.tex 
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In \cite{streitburger2014impact}, the researchers found that different pulse sequences and hardware (12 ch vs 32ch RF coil) altered the estimate of the coefficient on gray matter density in an age regression. This follows from our hypothesis on the scaling property of regional volumes from MRI. $D_{u,j}$ is the \textit{unobserved} effect - in the case of \cite{streitburger2014impact}, the true GM density dependence on age that cannot be measured directly. We have proposed that the reason for the differences seen in regional volume analyses (and possibly VBM) was due to different scaling biases, $a_j$, for different pulse sequences. It is definitely true that $a_j$ and $D_{Y,j}$(the \textit{observed} effect) are correlated, but the assumption of independence of the \textit{unobserved} effect ($D_{U,j}$) with $a_j$ needs to be validated, because it is possible that scaling factors may be different for different disease groups. To verify this assumption, we calculated scaling factors on MS patients and healthy controls and could not detect differences between them. Therefore, in the case of healthy controls (aged 24-57) and MS patients, $a_j$, is only dependent on scanner hardware/acquisition. hardware/acquisition parameters.