【推荐2】Scientists recently discovered that pictures on cave walls at Creswell Crags are the oldest know in Great Britain. But they didn’t find in the usual way.

Archaeologists often date cave art with a process called radiocarbon dating. The technique can measure the age of carbon found in charcoal(木炭) drawings or painted pictures. Carbon is an element(成分)found in many things, including charcoal and even people. But in this case, there was no paint things or charcoal to test. People carve the pictures of animals and figure into the rock using stone tools. The scientists had an “aha!” moment when they noticed small rocks stuck to the top of the drawings. The small rocks must have formed after the drawings were made. “It is rare to be able to scientifically date rock art,” said Alistair Pike, and archaeological scientist at Britain’s University of Bristol. “We were very fortunate that some of the engravings (雕刻) were covered by stalagmites(石笋).”

When a test proved that the stalagmites formed 12,800years ago, the scientists knew the art underneath them had to be at least that old. And some of the animals shown, like the European bison, are now extinct, another tip-off (征兆) that the art is quite old.

The artists came to Creswell Crags. This place is one of the farthest points north reached by our ancient ancestors during the Ice Age. At that time, much of the North Sea was dry, so people could move about more easily.

Some tools and bones found there are 13,000 to 15,0000 years old. They show that the travelers hunted horses, reindeer, and arctic hares. Their artwork is similar to art in France and Germany. It tells scientists that the Creswell Crags artists must have had a close connection to peoples several thousand kilometers away---- another important evidence of understanding how humans spread out across the world.

【推荐3】By trying to tickle (挠痒痒) rats and recording how their nerve cells respond, Shimpei Ishiyama and his adviser are discovering a mystery that has puzzled thinkers since Aristotle expected that humans, given their thin skin and unique ability to laugh, were the only ticklish animals.

It turns out that Aristotle was wrong. In their study published on Thursday, Ishiyama and his adviser Michael Brecht found that rats squeaked and jumped with pleasure when tickled on their backs and bellies. These signs of joy changed according to their moods. And for the first time, they discovered a special group of nerve cells. These nerve cells made this feeling so powerful that it causes an individual being tickled to lose control.

To make sure that he had indeed found a place in the brain where tickling was processed, Ishiyama then stimulated that area with electrical currents. The rats began to jump like rabbits and sing like birds.

“It’s truly ground-breaking,” said Jeffrey Burgdorf, a neuroscientist at Northwestern University who reviewed the paper. “It takes the study of emotion to a new level.”

Burgdorf has played a central role in our understanding of animal tickling. He was part of a team that first noticed, in the late 1990s, that rats made special noises when they were experiencing social pleasure. Others had already noted that rats repeatedly made short and high sounds during meals. But the lab where Burgdorf worked noticed that they emitted similar sounds while playing. And so one day, the senior scientist in the lab said, “Let’s go and tickle some rats.” They quickly found that those cries of pleasure doubled.

“The authors have been very adventurous,” said Daniel O’Connor, a neuroscientist at Johns Hopkins University who studies touch. To him, that finding was very surprising.

“Why does the world literally feel different when you are stressed out?” he said. “This is the first step towards answering that question. It gives us a way to approach it with experimental rigor (严谨).”

【推荐2】Eugene O' Neill, who was born in 1888, in New York, was a leading American drama writer and the winner of the Nobel Prize in Literature in 1936. His father was a successful touring actor. Because of that, Eugene spent his early childhood in hotels, on trains, and backstage. Although later in his life he grew to hate his father for not giving him security in his early years and a loving and comfortable family, he had the theater in his blood

As a student. O'Neill went to boarding schools but spent the summers in a moderate house his family owned. He left Princeton University in 1907, only about one year after he entered it, to start what he later called his real education in "life experience". At the age of 24, he was hired as a reporter and poetry column writer for the Net London Telegraph, where he worked for only a few months.

O'Neill didn't cut a figure in playwriting until the summer of 1916, when he was in a peaceful village of Provincetown. Massachusetts, where some young writers and artists had founded an experimental theater Before that, he had written awkward melodramas（情节剧）that were hardly accepted by the mainstream of American theater. While O'Neill was only one of those whose plays were produced by the theater, he led the group to success because of his contribution within the next few years. Between 1916 and 1920, the theater produced all of O'Neill's one-act sea plays. By the time his first full-length play, Beyond the Horizon, was produced on Broadway on February 2, 1920, at the Morosco Theater, the young playwright already had a small reputation.

Theater critics spoke highly of Beyond the Horizon for its tragic realism. The play brought O'Neill more public attention, as well as his first Pulitzer Prize, apart from which he won another three for Amna Christie, Strange Interlude, and Long Day's Journey Into Night. Over the next two decades. O'Neill continued to gain reputation nationally and globally. He became the most widely translated and produced dramatist after Shakespeare and Bernard Shaw.