flow depends separately on the cosmological parameters (see equation \[eq:sigv\] and the parametric form for the power spectrum in [@EH98]). But the most significant dependence is on $\sigma_8$ and $\Omega_m$ and hence we restrict ourselves here to deriving constraints on these two parameters only. We compute $nlP_{\rm o}$ for a grid of values of $\Omega_m$ and $\sigma_8$ used in $\Sigma_{\rm t}$, maintaining all other parameters at their default $\Lambda$CDM7 values. Confidence levels (CLs) on $\Omega_m$ and $\sigma_8$ are obtained by inspecting the contours of $\Delta \chi^2(\Omega_m,\sigma_8) =2(nlP_{\rm o}-{\rm min}(nlP_{\rm o}))$ in the $(\Omega_m,\sigma_8)$ plane. The minimum of $ nlP_{\rm o}$ (i.e. $\Delta \chi^2=0$ ) is at $(\Omega_m,\sigma_8)=(0.236,0.88)$, marked by the plus sign in the figure. The $\Lambda$CDM7 default values $(\Omega_m,\sigma_8)=(0.266,0.8)$ are indicated by the circle. The inner and outer contours of $\Delta \chi^2$ shown in figure (\[fig:sigom\]) correspond to 68% and 95% CLs for two degrees or freedom [@press]. The $\Lambda$CDM7 point is well within the 68% confidence level. The shape of the contours implies the correlation $\sigma_8\sim \Omega_m^{-0.28}$. This reflects the dependence of the shape of the density power spectrum $p_{_\delta}$ on $\Omega_m$ and from the factor $f(\Omega) \approx \Omega^{0.55}$ (see eq. \[eq:sigv\]). Only if we neglect the dependence 