(Stockholm) Scientists who discovered the AIDS virus, an outspoken U.S. economist and a Finnish diplomat who helped solve some of the world’s thorniest conflicts were honored Wednesday with the 2008 Nobel Prizes.

The 71-year-old said that “there is nothing higher” than receiving the award and divulged that the announcement in October had prompted him to reconsider retirement.

“I was planning to retire and sit in my rocking chair in my study and reading good books but when the news came that I had won the Nobel Peace Prize, I started getting calls from my friends who said you can’t retire now,” he said.

The peace prize ceremony was held in Oslo, Norway, while the Nobel awards in medicine, physics, chemistry, literature and economics were presented in the Swedish capital, Stockholm, in line with the 1895 will of prize founder Alfred Nobel.

The award ceremonies were followed by lavish banquets at which the laureates dine with Scandinavian royals, university professors, politicians and foreign diplomats.

Nobel’s will stipulates that the prizes, first handed out in 1901, should be given to those who “have conferred the greatest benefit on mankind” in their respective fields.

This year, five Europeans, four Americans and three Japanese were selected by the Nobel Prize committees.

The medicine prize jury cited French researchers Francoise Barre-Sinoussi and Luc Montagnier for their discovery of human immunodeficiency virus, or HIV, in 1983. They shared the award with Germany’s Harald zur Hausen, who was honored for finding human papilloma viruses that cause cervical cancer, the second most common cancer among women.

Japan’s Osamu Shimomura and Americans Martin Chalfie and Roger Tsien shared the chemistry prize for discovering and developing a fluorescent protein. Their work has helped researchers track such processes as the development of brain cells, the growth of tumors and the spread of cancer cells.

Japanese scientists Makoto Kobayashi and Toshihide Maskawa split the physics award with American Yoichiro Nambu for theoretical advances that help explain the behavior of the smallest particles of matter. Nambu, 87, canceled his trip to Stockholm for health reasons and was set to receive his award at a ceremony in Chicago.

The Swedish Academy continued a trend of honoring European writers by selecting Frenchman Jean-Marie Gustave Le Clezio for the literature prize. The author of more than 40 works including “The Book of Flights” and “Desert,” Le Clezio holds dual nationality with Mauritius and spends much of his time in Albuquerque, New Mexico.

U.S. economist and New York Times columnist Paul Krugman won the Nobel Memorial Prize in Economic Sciences for his analysis of how economies of scale can affect international trade patterns. The prize is not one of the original Nobels, but was created in 1968 by the Swedish central bank in Nobel’s memory.

The prizes – including a 10 million kronor ($1.2 million) purse, a diploma and a gold medal – are always handed out on Dec. 10, the anniversary of Nobel’s death in 1896. The Swedish industrialist and inventor of dynamite died in San Remo, a link that the Italian city marks by sending flowers to decorate the annual ceremony in Stockholm.