Before revision:  The two intervention strategies (SD and TQ) try to reduce the disease reproductive number R_0 to a target value R _0^{\rm target < 1, but in distinct ways, which we implement in our model equations.
After revision:  The two intervention strategies (SD and TQ) try to reduce the disease reproductive number , R_0, to a target value R _0^{\rm target < 1, but in distinct ways, which we implement in our model equations.