Proudly reading my words, I looked around the room, only to find my classmates bearing big smiles on their faces and tears in their eyes and Miss Lancelot stone-faced. I slowly raised the report, hoping to hide myself and burning to find out "What could be causing everyone to act this way?"

Quickly, I flashed back to the day Miss Lancelot gave me the task. This was the first real task I received in my new school. It seemed simple: go on the Internet and find information about a man named George Washington. Since my idea of history came from an ancient teacher in my home country, I had never heard of that name before. As I searched the name of this fellow, it became evident that there were two people bearing the same name who looked completely different! One invented hundreds of uses for peanuts, while the other led some sort of army across America. I stared at the screen, wondering which one my teacher meant. I called my grandfather for a golden piece of advice: flip (掷) a coin. Heads—the commander, and tails—the peanuts guy. Ah! Tails, my report would be about the great man who invented peanut butter, George Washington Carver.

When another classmate began his report, it all became clear, "My report is on George Washington, the man who started the American Revolution." How could I know that she meant that George Washington?

Obviously, my grade was awful. Heartbroken but fearless, I talked to Miss Lancelot, but she insisted: no re-dos; no new grade. I felt that the punishment was not justified, and I believed I deserved a second chance. Consequently, I threw myself heartily into my work for the rest of the school year. Ten months later, that chance unfolded as I found myself sitting in the headmaster's office with my grandfather and the headmaster informed me of his approval that I could skip the sixth grade. Justice is sweet!

Doctors sometimes prescribe light therapy to treat a form of depression in people who get too little morning sun. But too much light at other times may actually cause such mood disorders. Long-lasting exposure to light at night brings depression, a new study finds, at least in animals. The new data confirm observations from studies of people who work night shifts, says Richard Stevens of the University of Connecticut Health Center.

In the new study, Tracy Bedrosian and Randy Nelson of Ohio State University exposed mice to normal light and dark cycles for four weeks. For the next four weeks, half of the mice remained on this schedule, and the rest received continuous dim light throughout their night. Compared with mice exposed to normal nighttime darkness, those getting dim light at night lost their strong preference for sweet drinks, "A sign they no longer get pleasure out of activities they once enjoyed. "Bedrosian says.

In a second test, mice were clocked on how long they actively tried to escape a pool of water. Those exposed to night lights stopped struggling and just floated in the water, a sign of "behav- ioral despair", 10 times as long as the mice that had experienced normal nighttime darkness. All symptoms of depression disappeared within two weeks of the mice returning to a normal light- dark cycle, the researchers report. The scientists also could ease the behavioral symptoms by injec- ting the brains of animals with a drug that prohibits the activity of certain molecules （分子）linked with human depression. This finding further suggests that light at night may cause something related to depression.

Human studies linking nighttime light and mood disorders are important but can't easily detect molecular underpinings （分子基础）as animal studies can, says George Brainard of Thomas Jefferson University. The new work, he says, suggests that the change of the biological clock by light at night can be "an extremely powerful force in regulating biology and behavior. "

Parents, teachers and caregivers have long believed in the magic of storytelling to calm and comfort kids. Researchers working in pediatric (儿科) have now quantified the physiological and emotional benefits of a well- told tale.

"We know that narrative has the power to transport us to another world," says Brockington, who studies emotions and learning at Brazil's Federal University. He adds, "Earlier research suggested that stories help children process and regulate their emotions- but this was mostly conducted in a lab, with subjects answering questions while lying inside functional MRI machines. There's little research on physiological and psychological effects of storytelling in a more commonplace hospital setting."

So the investigators working in several Brazilian hospitals split a total of 81 patients aged 4 to 11 into two groups, matching them with storytellers who had a decade of hospital experience. In one group, the storyteller led each child in playing a riddle game. In the other, youngsters chose books and listened as the storyteller read them aloud. Before and after these sessions, the researchers took saliva (唾液) samples from each child, then asked them to report their pain levels and conducted a free association word quiz and analyzed samples.

Children in both groups benefited measurably from the interactions.

Those who heard stories also reported pain levels dropping almost twice as much as those in the riddle group, and they used more positive and light words to describe their hospital stay. The study demonstrates that playing games or simply interacting with someone can relax kids and improve their outlook but that hearing stories has an especially dramatic effect. "The researchers really tried to control the social interaction component of the storyteller, which I think was key," says Mar, a psychologist at York University.