1460478342-ab715de9-edcf-430e-af0e-700cf5eb71e6

A method is provided for fabricating an MOS transistor. In one embodiment two or more signals, which do not necessarily satisfy any symmetry assumptions individually, are combined into a composite signal which satisfies a symmetry assumption. The catalyst composition is highly effective at facilitating the vapor-phase condensation of formaldehyde with acetic acid to generate acrylic acid, particularly using an industrially relevant aqueous liquid feed.