<image>As shown in the figure, the axis of symmetry of the parabola \( y = ax^{2} + bx + c \) (where \( a > 0 \)) is a line passing through the point \( (1, 0) \) and is parallel to the \( y \)-axis. If the point \( P(4, 0) \) lies on the parabola \( l \), find the value of \( 4a - 2b + c \). 