In that question and its answers it was mentioned that you could trigger radioactive decay by bombarding atoms with gamma rays of the right energy level (there may be other solutions I do not know about, but of course if you bombard with neutrons you can trigger nuclear reactions)
I am mainly interested by beta-decay. Is it possible to decrease the probability of the beta decay of some radioactive material by a physical treatment?
Is the rate fairly independant of temperature and external magnetic field for instance?