It is known that the Korteweg-de Vries equation $$u_{t}+uu_{x}+u_{xxx} = 0,$$ with $u=u(x,t)$ smooth and with period equal to $L$, has important conservation laws, namely, $$E(u)=\frac{1}{2}\int_{0}^{L} u_{x}^{2} - \frac{1}{3}u^{3}\ dx\ \ \text{and}\ \ F(u)=\frac{1}{2}\int_{0}^{L}u^{2}\ dx.$$
$E$ and $F$ are independent of the temporal variable $t$.
It is also knoun that the Degasperis-Procesi equation $$u_{t}-u_{xxt} = uu_{xxx}+3u_{x}u_{xx}-4u u_{x}$$ has a infinite number of conservation laws.
Question: Are there conservation laws for modified Degasperis-Procesi equation $$u_{t}-u_{xxt} = uu_{xxx}+3u_{x}u_{xx}-4u^{2}u_{x}\ \ ?$$