$$\frac{\partial U}{\partial t}=\alpha \frac{\partial^2 U}{\partial x^2}+\beta U$$
I have been given this partial differential equation and am asked to find an application for it. I can see that the partial terms correspond to the heat diffusion equation but I am having trouble understanding what the last term on the right represents. I am additionally tasked with finding relevant values for $\alpha$ and $\beta$, but if I can understand that far-right term or find an overall application then I can find the relevant ranges for these values. Any tips or help would be greatly appreciated.