George Gershwin, born in 1998, was one of America's greatest composers. He published his first song when he was eighteen years old. During the next twenty years he wrote more than five hundred songs.

Many of Gershwin's songs were first written for musical plays performed in theatres in New York City. These plays were a popular form of entertainment in the 1920s and 1930s. Many of his songs have remained popular as ever. Over the years they have been sung and played in every possible way — from jazz to country.

    In the 1920s there was a debate in the United States about jazz music. Could jazz, some people asked, be considered serious music? In 1924 jazz musician and orchestra leader Paul Whiteman decided to organize a special concert to show that jazz was serious music. Gershwin agreed to compose something for the concert before he realized he had just a few weeks to do it. And in that short time, he composed a piece for piano and orchestra which he called Rhapsody in Blue. Gershwin himself played the piano at the concert. The audience were thrilled when they heard his music. It made him world-famous and showed that jazz music could be both serious and popular.

    In 1928, Gershwin went to Paris. He applied to study composition (作曲)with the well-known musician Nadia Boulanger, but she rejected him. She was afraid that classical study would ruin his jazz-influenced style. While there, Gershwin wrote An American in Paris. When it was first performed, critics (评论家)were divided over the music. Some called it happy and full of life, to others it was silly and boring. But it quickly became popular in Europe and the United States. It still remains one of his most famous works.

    George Gershwin died in 1937, just days after doctors learned he had brain cancer. He was only thirty-nine years old. Newspapers all over the world reported his death on their front pages. People mourned the loss of the man and all the music he might have still written.

As we age, even if we're healthy, the heart just isn't as efficient in processing oxygen as it used to be. In most people the first signs show up in their 50s or early 60s. And among people who don't exercise, the changes can start even sooner.

"Think of a rubber band. In the beginning, it is flexible, but put it in a drawer for 20 years and it will become dry and easily broken," says Dr. Ben Levine, a heart specialist at the University of Texas. That's what happens to the heart. Fortunately for those in midlife, Levine is finding that even if you haven't been an enthusiastic exerciser, getting in shape now may help improve your aging heart.

Levine and his research team selected volunteers aged between 45 and 64 who did not exercise much but were otherwise healthy. Participants were randomly divided into two groups. The first group participated in a program of nonaerobic (无氧) exercise—balance training and weight training—three times a week. The second group did high-intensity aerobic exercise under the guidance of a trainer for four or more days a week. After two years, the second group saw remarkable improvements in heart health.

"We took these 50-year-old hearts and turned the clock back to 30-or 35-year-old hearts," says Levine. "And the reason they got so much stronger and fitter was that their hearts could now fill a lot better and pump (泵送) a lot more blood during exercise." But the hearts of those who participated in less intense exercise didn't change, he says.

"The sweet spot in life to start exercising, if you haven't already, is in late middle age when the heart still has flexibility," Levine says. "We put healthy 70-year-olds through a yearlong exercise training program, and nothing happened to them at all."

Dr. Nieca Goldberg, a spokeswoman for the American Heart Association, says Levine's findings are a great start. But the study was small and needs to be repeated with far larger groups of people to determine exactly which aspects of an exercise routine make the biggest difference.

Goffin's cockatoos, a kind of small parrot native to Australasia, have been shown to have similar shape-recognition abilities to a human two-year-old. Though not known to use tools in the wild, the birds have proved skilful at tool use while kept in the cage. In a recent experiment, cockatoos were presented with a box with a nut inside it. The clear front of the box had a "keyhole" in a geometric shape, and the birds were given five differently shaped "keys" to choose from. Inserting the correct "key" would let out the nut.

In humans, babies can put a round shape in a round hole from around one year of age, but it will be another year before they are able to do the same with less symmetrical（对称的） shapes. his ability to recognize that a shape will need to be turned in a specific direction before it will fit is called an "allocentric frame of reference". In the experiment, Goffin's cockatoos were able to select the right tool for the job, in most cases, by visual recognition alone. Where trial-and-error was used, the cockatoos did better than monkeys in similar tests. This indicates that Goffin's cockatoos do indeed possess an allocentric frame of reference when moving objects in space, similar to two-year-old babies.

The next step, according to the researchers, is to try and work out whether the cockatoos rely entirely on visual clues（线索）, or also use a sense of touch in making their shape selections.