The 2012 Nobel Prize season opens Monday with the award for medicine, marking the start of a week of announcements and speculation over who will collect the literature and peace prizes.
The medicine prize will be announced in Stockholm at 11:30 am (0930 GMT) at the earliest.
With the awards committees keeping mum on their choices, Nobel watchers are left to play a guessing game.
Swedish media have suggested the medicine prize could go to Japan's Shinya Yamanaka and Britain's John Gurdon for their research in nuclear reprogramming, a process that instructs adult cells to form early stem cells which can then be used to form any tissue type.
James Till of Canada could also be honoured for his related work on blood stem cells.
Other medicine fields cited as worthy of Nobel recognition this year are epigenetics, which studies how genes respond to their environment, and optogenetics, where researchers can turn on or off a nerve cell, for example in a fruit fly or a mouse, to reprogramme the brain.
Japanese media voiced hope Yamanaka was in with a chance, with the Nikkei business daily declaring he was a "sure" thing for a Nobel one day, but conceding it might not be this year.
"It's a matter of time," it said.
The winner of the Nobel Peace Prize, perhaps the most watched of the prestigious awards, will be revealed Friday in Oslo, and the five-member Norwegian Nobel committee has 231 nominees to choose from this year.
No clear frontrunner has emerged so far, although Coptic Christian Maggie Gobran of Egypt, dubbed the "Mother Teresa" of Cairo's slums, tops the list of one betting site with odds of 6.5-to-1.
The committee keeps the list of nominees a well-guarded secret, but those who are entitled to nominate candidates can disclose the names they have put forward so the list is known to include former US president Bill Clinton, ex-German chancellor Helmut Kohl, the EU and WikiLeaks suspect Bradley Manning.
The head of the Peace Research Institute of Oslo, Kristian Berg Harpviken, follows the work of the committee and each year publishes his own shortlist of possible winners.
It includes US political scientist Gene Sharp, an expert on non-violent revolution; Russian rights group Memorial and its founder Svetlana Gannushkina; and independent Russian media outlet Echo of Moscow and its chief editor Alexei Venediktov.
A Nigerian duo campaigning against the misuse of religion, Archbishop John Onaiyekan and Mohamed Sa'ad Abubakar, Sultan of Sokoto, are also on it, as is Myanmar President Thein Sein.
Afghan human rights activist, ex-minister and burka opponent Sima Samar is meanwhile also seen as a possible winner, as is Cuban human rights activist Oscar Elias Biscet.
The other closely-watched award is the literature prize, with the usual names being tossed around Stockholm's literary circles.
Among them are Chinese author Mo Yan, Japan's Haruki Murakami, Canadian short story writer Alice Munro, US authors Don DeLillo and Philip Roth, Somali novelist Nuruddin Farah and Egyptian writer Nawal el Saadawi.
The date has not been set for the literature prize announcement, although it is traditionally on a Thursday and could therefore come on October 11.
Much buzz has focused on the physics prize this year, to be announced Tuesday, after the discovery in July of a new fundamental particle believed to be the Higgs boson.
It is one of the biggest breakthroughs in the field of physics in the past half-century, and is widely considered Nobel prize-worthy research.
The chemistry prize will be announced on Wednesday, with Swedish Radio suggesting Svante Paeaebo of Sweden could win for his groundbreaking analysis of ancient DNA.
The economics prize, dominated by Americans over the years, will wind up the Nobel season on October 15.
Because of the economic crisis, the Nobel Foundation has slashed the prize sum to eight million Swedish kronor ($1.2 million, 930,000 euros) per award, down from the 10 million kronor awarded since 2001.
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