Disappearance of hoarding behavior after 6-hydroxydopamine lesions of the mesolimbic dopamine neurons and its reinstatement with L-dopa

In an exhaust bypassing system for a turbocharger for use with an internal combustion engine such as automobile engine, an opening is provided in the wall of an exhaust passage so as to introduce the exhaust pressure of the engine into the interior of a diaphragm of a valve assembly which adjusts the quantity of exhaust gas to be bypassed and in which a rod having a valve body at its fore end is attached to the diaphragm.