Quarantine "yellow jack" but this was also a name for yellow fever, which probably derives its common name from the flag, not the color of the victims (cholera ships also used a yellow flag). The plain yellow flag ("Quebec" or Q in international maritime signal flags) probably derives its letter symbol for its initial use in "quarantine", but this flag in modern times indicates the opposite—a ship that declares itself free of quarantinable disease, and requests boarding and routine port inspection. Australia has perhaps the world's strictest quarantine standards. Quarantine in northern Australia is important because of its proximity to South-east
Flag of Portugal Flag of Portugal The Flag of Portugal () is a rectangular bicolour with a field unevenly divided into green on the hoist, and red on the fly. The lesser version of the national coat of arms (i.e. armillary sphere and Portuguese shield) is centered over the colour boundary at equal distance from the upper and lower edges. On 30 June 1911, less than a year after the downfall of the constitutional monarchy, this design was officially adopted for the new national flag of the First Portuguese Republic, after selection by a special commission whose members included Columbano Bordalo Pinheiro, João