summary for two articles

The first article is about a British team who trek to the North Pole to measure how fast he Arctic sea-ice is melting. The famous Arctic explorer Pen Hadow and his teammates arrived at the northern coast of Canada on Saturday. They schedule to measure the thickness of the ice and provide the most detailed survey in this season. The thickness of ice is measure by a mobile radar unit. This expedition provides scientists with a better understanding of how fast the ice is shrinking. Many people believe that the sea-ice is melting at a faster rate due to the increase in air temperature above the ice and also because of warmer waters underneath it. The majority of scientific institutions and agencies who study the Arctic believe that global warming is responsible for the changes. Back to a few years, researchers foresee that all the ice could have molten in summer by the end of this century. Mr Hadow and his Survey group are trying to collect crucial up to date data about the status of the ice in winter and early spring. It is the period when the amount of ice is at its maximum. This can provide scientists the most recent data of Arctic ice.
The second article is about the US nuclear relic found in bottle. According to scientists the bottle contains the oldest sample of bomb-grade plutonium made in nuclear reactor. The source of nuclear waste is identified by a team from the Pacific Northwest National Laboratory used nuclear forensic techniques. The insights can be found in the latest edition of the journal Analytical Chemistry. The mysterious bottle was found in a burial trench at the Hanford nuclear site in Washington State, north-western US. The sample was produced at the Hanford site in Trinity. In order to retrieve bomb-grade plutonium, used nuclear fuel was moved from a reactor to a chemical reprocessing plant. A large scale environmental cleanup is carried out at the Hanford site due to highly radioactive nature of the waste. The process of identifying the age of sample is quite complicated. The researchers study the different isotopes of plutonium and uranium and conclude that it originated from the spent fuel in 1944. The researchers concern that the current nuclear renaissance and high access to these material by the public could encourage smuggling of fissionable materials in future.
Article 1 is from BBC news, Sunday,1 March 2009, Explorers begin epic Arctic trek.
Article 2 is from BBC newsMonday,2 March 2009，by Paul Rincon, US nuclear relic found in bottle.