A capacitor connected to a battery initially holds a charge of \(+q\) on its positive plate and \(-q\) on its negative plate. The electric field between the plates is initially \(\vec{E}\). A dielectric material is then inserted that polarizes in such a way as to produce an electric field of \(-0.30 \vec{E}\) (where the - sign indicates that this field opposes the initial field \(\vec{E}\) ). Determine the new charge stored on the positive plate.