The researchers showed that light was activating in the mice a protein, melanopsin, which also has a role in regulating the body clock, and is present in people. However, whether the same processes take place in people or other animals is unknown.
He said more research was still needed, but the findings may lead to considerations of light levels during pregnancy and efforts to grow retinas in the laboratory.
"He was also not afraid to laugh at himself and rejoiced in the huge postbag of letters which poked gentle fun at him - often he would forward particularly insulting letters that had been sent straight to him for inclusion alongside his column. He will be greatly missed.
He was on the brink of death five times and underwent a gruelling 19 operations, including the removal of three tendons, leaving him with mobility difficulties.
One said he broke his shoulder and suffered hand and leg injuries. "When the bombardment ended I tried to help the people who were injured," he was quoted as saying.
However, there was some speculation in Spanish media that Mr Rajoy, in one of his answers at the press conference, appeared to have admitted that some of what the El Pais newspaper published was correct.
And then, there is me. One frosty morning I arrived at my local station to find that the ticket machine was broken. No matter, I thought, I have got a smartphone, and I hurriedly set about buying my ticket that way
This was not as easy as I had hoped, fiddling between credit card and phone with freezing cold fingers, but, by the time I got on the intercity to Geneva I had an e-ticket and I proudly showed it to the conductor.
Unfortunately she was less than impressed and told me in no uncertain terms that my ticket was not valid. Why, only became clear several weeks later when a letter arrived from Swiss railways euphemistically named "revenue protection service".
But it became clear that the air traffic authorities were not going to grant that permission. The reasoning was that Germany's military drones would be unable to avoid collisions with other, civilian aircraft.
The Rosphere was developed by a four-strong team at the Technical University of Madrid (UPM) who tried to find a method of locomotion that would not be thwarted by uneven or difficult terrain. Wheeled and legged robots can struggle on shifting ground or places strewn with lots of large and small objects.
