Keep a sleep rhythm, maintain hope and psychological balance within a group confined to a narrow space are some of the challenges facing the 33 miners trapped 700 meters underground in Chile in order to survive four months.
"It's easy to survive as a group. If you are alone you can get carried away by despair, thinking that can not be saved. As a group, if one weakens the others to encourage, "he told AFP Michel Siffre, caver and scientist who has conducted numerous experiments in extreme conditions of confinement.
"When survival is at stake joins the group. In all the experiences of survivors facing psychological problems after the departure. Given the danger, endure, "says Henry by his side Vaumoron, secretary general of the French Federation of Speleology.
"But as in the raft of the Medusa, where many survivors are killed each other, or the Uruguayan plane crash in the Andes in 1972, survived by cannibalism, the situation can escalate," says Siffre , who spent two months only a hundred meters deep and freezing temperatures in 1962.
An experiment conducted several decades ago by the U.S. space agency NASA, a team in complete autarky showed that four members of the mission could not bear to fifth and even wanted to kill him, he explains.
"In survival situations that becomes Darwinian. The strong survive. And the mental attitude is paramount. You have to believe. Those who believe in survival are more likely to save than those who are left to chance, "recalls Siffre.
To arrange group life and resolving disputes should arise "heads": a superior officer or individual that in those exceptional moments assume a leadership role, according Siffre.
The survivors have to keep pace with the dream that on the surface, because without the light of day you lose track of time.
"Exercises survival conducted in caves without any temporal reference have shown that the body has a biological clock that goes to work for periods of 26 hours, "explains Sophie Lumineau, a researcher in chronobiology at the University of Rennes.
"But this clock differs slightly between individuals. Either everyone is going to synchronize with an average rate, or one of them impose their rhythm on the others "he explains.
With any communications with first responders, they may set the pace from the outside world, such as delivering food at fixed times. And will probably have light bulbs they had passed through the canal.
To allow them to survive will have to renew the oxygen, water and food supply them. Must constantly rehydrate, drink steadily since the 33 degrees Celsius, water evaporates from the body permanently.
'We must give them more liquid diet. The less you go to the toilet will be better. When you're locked in the ground, you have to dig trenches for excrement, "said Henry Vaumoron.
"They all have vision problems when exiting. There has been an increase in myopia, vision relief and colors when you live without light, "says Siffre.
"The essential thing is to get out alive, but no free will," believes.
01 October is "Journalists Day" in Peru date on which recalls the day when the first newspaper appeared in Peru and America, "Diario de Lima" founded by Jaime Bausate and Meza, requesting members of 
