Gay and lesbian couples who were hoping to get married in California this week were dealt a setback Monday when the Ninth Circuit Court of Appeals ruled that no same-sex marriages could take place in the state while the court considers the constitutionality of the state’s gay marriage ban. The appeals court decision reverses a ruling last week by US District Court Chief Judge Vaughn Walker, who had said marriages could resume while higher courts considered the matter. Walker was the federal judge who struck down Proposition 8, the state’s voter-approved ban on same-sex marriages. The appeals court said it would hear the Proposition 8 challenge on an expedited basis and hold arguments the week of December 6.