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 Sweden used from a flagpole extending from a building, the flag is recommended to have a width equaling a third of the height (length) of the pole. It is further recommended to fly the flag only during daytime, and to lower it no later than 9 pm. Only when the country is at war is it recommended to fly the flag also at night. The king and queen use a royal flag with the greater national coat of arms. Other members of the royal house use a royal flag with the lesser national coat of arms. On naval ships the flag