Brazil's capital is bracing for the possibility of more violent demonstrations by people seeking to overturn the presidential election. Local security officials are blocking access to buildings trashed on Sunday by rioters. A flyer promoting a "mega-protest to retake power" circulated on social media platforms urging protesters to turn out Wednesday in two dozen cities, including the capital. It is unclear how large or violent such demonstrations might shape up to be, but skittish authorities are taking no chances. The federal appointee who has assumed control of the capital's security says police are shutting down the main avenue to traffic and limiting pedestrian access with barricades. They will block all access to the square that was the site of Sunday's mayhem.