Surfactant: A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue, preventing the alveoli from collapsing.urfactant: A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue, preventing the alveoli from collapsing.
Guy Fawkes' Day is not a public holiday. Businesses, organizations and schools are open as usual. Public transport services run to their normal timetables. Some organizations, communities and municipalities may organize public bonfires or displays of fireworks on or around November 5.
For other uses, see Labor Day (disambiguation). Labor Day in the United States is a public holiday celebrated on the first Monday in September. It honors the American labor movement and the contributions that workers have made to the strength, prosperity, laws and well-being of the country. It is the Monday of the long weekend known as Labor Day Weekend and it is considered the unofficial end of summer. The holiday is also a federal holiday. Beginning in the late 19th century, as the trade union and labor movements grew, trade unionists proposed that a day be set aside to celebrate labor.