Figure 1

Schematic diagram of the model (4) where \(\lambda _{1}=\frac{\beta _{h1}^{\sigma }I_{v1}}{1+\alpha _{1}^{\sigma }I_{v1}} ~and~\lambda _{2}=\frac{\beta _{h2}^{\sigma }I_{v2}}{1+\alpha _{2}^{\sigma }I_{v2}}\).

Schematic diagram of the model (4) where \(\lambda _{1}=\frac{\beta _{h1}^{\sigma }I_{v1}}{1+\alpha _{1}^{\sigma }I_{v1}} ~and~\lambda _{2}=\frac{\beta _{h2}^{\sigma }I_{v2}}{1+\alpha _{2}^{\sigma }I_{v2}}\).