By Alexandra Ulmer RIO DE JANEIRO, Aug 9 (Reuters) - Brazil's first gold medal has boosted Olympic ticket sales and organisers expect attendance to pick up in coming days, although some venues including the Copacabana beach volleyball arena are still struggling to fill seats. Judoka Rafaela Silva, who grew up in Rio's notorious Cidade de Deus favela, burst into tears on Monday as she held up her medal to a roaring crowd as the Brazilian national anthem played. ''There is nothing better for ticket sales than when the country wins its first gold,'' Games spokesman Mario Andrada told reporters on Tuesday. More...