A dashboard for a motor vehicle is prearranged in such a way that the air for ventilation of the passenger compartment of the motor vehicle that exits from a top opening of the dashboard is deviated, by the Coanda effect, along the top surface of the dashboard and beyond the dashboard in the direction of the occupants of the passenger compartment. A plurality of passages are defined in the body and a plurality of recesses are defined radially in an outer periphery of the body. In one implementation, an implantable device is programmed to deliver the vascular therapy in response to low blood pressure or orthostatic hypotension. The Mach-Zehnder type semiconductor device also can suppress optical loss of the first and second light, and generate outgoing light without deterioration.