Suppose you are modelling a population of a single species at a time $t$, $N_t$. But to make it slightly simpler you want to explore $\hat{N_t}$, which is defined by $\hat{N_t} = \frac{N_t}{K}$ where $K$ is the carrying capacity of the population.
The Ricker model has the standard equation
$N_{t+1} = N_te^{r\left({1 - \frac{N_t}{k}}\right)}$
Which using $\hat{N_t}$ becomes
$\hat{N}_{t+1} = \hat{N}_te^{r\left(1 - \hat{N_t}\right)}$.
However the variation of this that I am looking at is
$\hat{N}_{t+1} = \hat{N}_te^{r\left(1 - \hat{N_t}\right)} + Q$.
What is the meaning of Q here and how does this affect population growth over time?