"The bird doesn't actually hear his song when he is sleeping, because he is not producing any sound, " said Dr Deregnaucourt.

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"Whenever he is not sleeping or eating, he is working, " recalls Zhang, now at Harvard.

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"Once he gets like that, he is just sleeping but they can monitor him, " she said.

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Takashi Shibaguchi, a 41-year-old acupuncturist who lived on the outskirts of the town, says he will never return home, even though he has no money and is sleeping on the floor of an evacuation shelter with his wife and four-year-old daughter.

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Mohammed is typical: He spent three months sleeping in a park before finally getting a hotel room provided by the French state, once he was able to prove he was 16 years old.

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The details remain hazy, but it casts a "Chinatown"-size cloud over Ray and probably accounts for the state of his marriage -- which is over -- and the fact that he's sleeping on his dad's leaky sailboat.

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The sanitation is a disaster and many are sleeping in roads and car parks, he adds.

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