The 2011 Nobel laureates in medicine, literature, economics, physics and chemistry received their prizes from Swedish King Carl XVI Gustaf at a gala ceremony in Stockholm on Saturday. The formal event, held as tradition dictates on the anniversary of the death of prize founder Alfred Nobel in 1896, took place at Stockholm's Concert Hall which was decked out in white, yellow and orange flowers for the occasion. The laureates and guests were clad in white tie and tails for men and evening gowns for women. Notably absent was one of the three winners of the Nobel Medicine Prize, Ralph Steinman of Canada, who passed away just three days before the award was announced on October 3, unbeknownst to the Nobel committee. While Nobel prizes are not awarded posthumously, the committee decided to maintain its decision to give him one half of the prestigious prize since it had not been aware of his death. His wife Claudia Steinman accepted the honour on his behalf at Saturday's ceremony. Bruce Beutler of the United States and Luxembourg-born Frenchman Jules Hoffmann shared the other half of the Medicine Prize, which this year honoured research on the immune system. The Physics Prize was meanwhile awarded to Saul Perlmutter and Adam Riess of the United States and US-Australian Brian Schmidt for their discovery that the expansion of the Universe is accelerating. Israeli scientist Daniel Shechtman received the chemistry Nobel for discovering quasicrystals, an atomic mosaic whose existence was initially ridiculed before fundamentally altering theories about solids. This year's Literature Prize went to Swedish poet Tomas Transtroemer, whose works address themes of nature, everyday life and death. Transtroemer, 80, suffered a stroke in 1990 which left his speech slurred, and he was in a wheelchair on Saturday. Finally, US researchers Thomas Sargent and Christopher Sims won the Economics Prize for research on the causal relationship between economic policy and different macroeconomic variables, such as GDP, inflation, employment and investments. The Nobel Prize consists of a gold medal, a diploma, and 10 million kronor ($1.48 million dollars, 1.10 million euros), to be shared if there is more than one recipient. The laureates were also to be honoured at a formal dinner banquet later in the evening attended by the royal family and some 1,400 specially-invited guests. Earlier Saturday in Oslo, the Nobel Peace Prize was awarded to Liberian President Ellen Johnson Sirleaf, her compatriot and "peace warrior" Leymah Gbowee and Yemeni "Arab Spring" activist Tawakkol Karman.