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\begin{eqnarray}
\sf 
\zeta & = & \sqrt{ 1 + \frac{h}{\tau} \left(
\frac{\frac{3}{2}k_BT_0N}{\sum \frac{p^2}{2m}} - 1 \right) } \nonumber\\
\vec{p}_i & = & \zeta \vec{p}_i \nonumber
\end{eqnarray}
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