Decompression sickness can be prevented by decreasing the pressure slowly. This allows the gases which have dissolved in the body to get out in the breathing air without forming bubbles. Divers do this by coming up to the surface slowly, as the pressure depends on the depth, and reducing the depth will reduce the pressure. For each ten metres change of depth the pressure will change by 1 bar, which is about the same as normal air pressure at sea level.
Divers find out how slowly to come up by using decompression tables or a dive computer. They may need to stop on the way up to wait for enough gas to get out before it is safe to go up further. This is called a decompression stop. The tables or computer will inform the divers what depths they must stop at and how long they must stay at each depth.
People flying high in aircraft avoid decompression by being in a pressurized cabin. In military aircraft the crew may breathe oxygen before the flight for a few hours so most of the nitrogen that is dissolved in their bodies can escape. This is called oxygen prebreathing.
Astronauts preparing for a spacewalk also prebreathe oxygen and decompress inside the spacecraft before getting into their suit and going outside.
When a person breathes, the air or other breathing gas dissolves into the blood from the lungs. This takes some time, and the amount of gas that can dissolve depends on the pressure around the person. If the pressure is greater, more gas can dissolve. After a while no more gas can dissolve at that pressure.
When a diver goes deeper, the pressure gets greater. This makes more gas dissolve in the diver. At the end of the dive the diver must return to the surface of the water where there is less pressure.
If the diver goes up slowly the pressure will change slowly, and there will be enough time for the gas dissolved in the diver to return from the blood to the breathing gas in the divers lungs and it will be safely removed. If the pressure change is too quick for enough of the dissolved gas to be removed, the gas may form bubbles in the blood and other parts of the diver's body. These bubbles will get bigger when the pressure gets less as the diver gets nearer to the surface. Bubbles which are in the blood may get stuck in small blood vessels. If this happens in the lungs they will usually do no great harm but if they block the blood flow in other parts of the body, the parts where the flow is blocked will not get enough oxygen and may be damaged. This is very dangerous if it happens in the brain or heart. The other place where bubbles may form is in the more solid parts of the body. If these bubbles grow enough they may tear the parts around them or press against them hard enough to do damage.
If a diver gets decompression sickness it can be treated by putting the diver in a decompression chamber, and increasing the pressure to squeeze the bubbles to a smaller size where they do less harm, and by giving the diver pure oxygen to breathe, which helps to get the bubbles to dissolve again. The oxygen also helps to stop more damage to the body by the bubbles which have blocked blood vessels, as there is more oxygen in the blood to keep the parts alive which have less blood supply because of the blockages.
Buzzword
A buzzword is a word or phrase that is made to either summarize a complex idea or reconstruct another word or phrase to reflect a particular point of view. Corporations make up buzzwords so that they can advertise stuff better. In this way, a buzzword is a lot like a product name or a proper noun. People can remember buzzwords better than non-buzzwords, which is why its good for advertising.
Example:
Multimedia has been a buzzword in the computer industry for years.
International trade
International trade is when countries agree to allow their businesses to exchange products or resources, also known as importing and exporting goods. Businesses in one country will then buy (import) or sell (export) goods to the businesses in other countries. Alternatively, the government of a country will sometimes directly buy from (or sell to) the government of another country.
When import of goods affects the prices of those same goods in the receiving country, that country's government may pass special laws to regulate the trading. They may then try to use protectionist methods such as high tariffs to discourage import.
As a form of punishment or political pressure, some countries may impose economic sanctions, or embargoes that prevent trading altogether with a target country.
To promote relations, countries may agree to trade with each other without protectionism. This is called "free trade". Free trade reduces trade barriers in exporting items.
Narew
Narew is a river in northeast Poland, and western Belarus. It is long and empties into the Vistula.
Division of Higgins
The Division of Higgins is an Australian Electoral Division in Victoria.
It was created in 1949 and is named after Justice H. B. Higgins (1851–1929). Higgins was a member of the Victorian Legislative Assembly (1894), president of the Carlton Football Club (1904), a member of the Australian House of Representatives (1901–1906), and a judge of the High Court of Australia (1906–1929).
The Division of Higgins covers the inner eastern suburbs of Melbourne, including Armadale, Ashburton, Malvern, Toorak and parts of Glen Iris, Camberwell, Carnegie, Murrumbeena, Prahran, and South Yarra.
Higgins has been important in Australian federal politics and for the Liberal Party of Australia. The seat's first two members, Harold Holt and Sir John Gorton, were the 17th and 19th Prime Ministers of Australia. Higgins is the only Division to have been held by two Prime Ministers.
Peter Costello the longest serving Treasurer of Australia and former Deputy Leader of the Liberal Party also held the seat from 1990–2009. He resigned in 2009 which meant a by-election had to be held. There had also been a by-election in 1967, after Harold Holt disappeared in the sea.
Division of Murray
The Division of Murray was an Australian Electoral Division in the state of Victoria.
It was located in the north of the state, next to the Murray River, which forms Victoria's border with New South Wales. It included the towns of Shepparton, Echuca, Cobram, Yarrawonga, Boort and Bridgewater.
Murray was created in 1949. It was named after the Murray River, which itself was named after British Secretary of State for War and the Colonies Sir George Murray.
The Division was abolished in 2019 and renamed Nicholls.
It was first held by Rt Hon Sir John McEwen, who was the caretaker Prime Minister of Australia after the disappearance of Harold Holt.
Shepparton
Shepparton () is a city on the floodplain of the Goulburn River in the north east of Victoria, Australia. It is about north-east of Melbourne. In 2006 there were 27,707 living in the city.
Shepparton began as a sheep station and river crossing. It later became an important railway town. Today it is an agricultural and manufacturing city. It is at the centre of the Goulburn Valley irrigation system, one of the largest centres of irrigation in Australia. It is a major regional service city and is the civic administration centre for the City of Greater Shepparton. The Greater Shepparton area includes the towns of Tatura, Merrigum, Mooroopna, Murchison, Dookie, and Grahamvale.
Tatura
Tatura is a town in the Goulburn Valley region of Victoria, Australia, Australia. The town part of the City of Greater Shepparton local government area. It is north of the state capital, Melbourne and west of the regional centre of Shepparton. In 2011 there were 3,672 people living in the town.