Simplest Equilibrium Turnover Model
NewOnlyVirus = OnlyVirusDeaths = OnlyVirus*Virus death rate
After time 510, NewOnlyVirus=0
Initial Value of OnlyVirus compartment is 1990. It stays there
until time 510 because inflow balances outflow
The rate of fall of virus levels after therapy is started tells
us how fast viruses are being produced