They wear the latest fashions with the most up-to-date accessories(配饰)．Yet these are not girls in their teens or twenties but women in their sixties and seventies．A generation which would once only wear old-fashioned clothes is now favouring the same high street looks worn by those half their age．

Professor Julia Twigg, a social policy expert, said, “Women over 75 are now shopping for clothes more frequently than they did when they were young in the 1960s．In the 1960s buying a coat for a woman was a serious matter．It was an expensive item that they would purchase only every three or four years — now you can pick one up at the supermarket whenever you wish to．Fashion is a lot cheaper and people get tired of things more quickly．”

Professor Twigg analysed family expenditure(支出) data and found that while the percentage of spending on clothes and shoes by women had stayed around the same — at 5 or 6 percent of spending — the amount of clothes bought had risen sharply．

The professor said, “Clothes are now 70 percent cheaper than they were in the 1960s because of the huge expansion of production in the Far East．In the 1960s Leeds was the heart of the British fashion industry and that was where most of the clothes came from, but now almost all of our clothes are sourced elsewhere．Everyone is buying more clothes but in general we are not spending more money on them．”

Fashion designer Angela Barnard, who runs her own fashion business in London, said older women were much more affected celebrity(名流) style than in previous years．

She said, “When people see stars such as Judi Dench and Helen Mirren looking attractive and fashionable in their sixties, they want to follow them．Older women are much more aware of celebrities．There’s also the boom in TV programmes showing people how they can change their look, and many of my older customers do yoga to stay in shape well in their fifties．When I started my business a few years ago, my older customers tended to be very rich, but now they are what I would call ordinary women．My own mother is 61 and she wears the latest fashions in a way she would never have done ten years ago．”

Seals may sound different than expected from their body size. Is this ability related to their vocal talents or is it the result of adaptation? An international team of researchers led by scientists from the Max Planck Institute investigated the vocal tracts (声道) of seals, which matched their body size. This means that seals are capable of learning new sounds.

Most animals produce calls that reflect their body size. A larger animal will sound lower-pitched because its vocal tract, the air-filled tube that produces sounds, is longer. But seals do not always sound like they look. They may sound larger, perhaps to impress an enemy; or smaller, perhaps to get attention from their mothers. Are these animals very good at learning sounds, or have their vocal tracts adapted to allow this vocal flexibility (灵活性)?

To answer this question, Professor De Reus worked together with researchers from the Max Planck Institute. The team measured young seals’ vocal tracts and body size. The measurements were taken from 68 young seals (up to twelve months old) who had died. The team also re-analyzed previously gathered seal vocal data to confirm their impressive vocal flexibility.

De Reus found that the length of seals’ vocal tracts matched their body size. There were no anatomical (身体结构的) explanations for their vocal skills. Meanwhile, the researchers argue that only vocal learning can explain why seals do not sound like they look. “Vocal learners will sound different from their body size, but the size of their vocal tracts will match their body size. The combined findings from acoustic (听觉的) and anatomical data may help us to identify more vocal learners,” says de Reus. “Studying different vocal learners may help us to find the biological bases of vocal learning and shed light on the evolution of complex vocal systems, such as speech. The more we look, the more we see that it would help to study human speech ability.”

Someday, you may no longer need to brush your teeth by hand. Instead, a group of billions of nanoparticles (纳米粒子) could automatically do it for you. It would be especially life-changing for those who find it difficult or impossible to hold and move a toothbrush.

Steager, an engineer at the University of Pennsylvania in Philadelphia and Hyun Koo, an inventor and dental researcher there, found a way to form the nanoparticles into long, skinny bristles (刷毛), a lot like the ones on a toothbrush. But these bristles shape-shift to fit whatever surface they encounter.

The tooth-cleaning robot works due to two magnets (磁铁). One goes each side of the teeth. The nanoparticles sit in a liquid between the magnets. When the magnets are turned off, the nanoparticles move randomly in the liquid. As soon as one magnet gets turned on, the nanoparticles gather together near its center. When the researchers turn on the other magnet and turn off the first one, the nanoparticles extend outward in long, skinny bristles. When there’s a tooth in the way, these bristles can’t stretch out as far as they want. So they push against the tooth’s surface. If there’s a gap between teeth, they push into the gap. Moving the magnets makes the bristles move against and between teeth. All that motion cleans the teeth. As a bonus, the nanoparticles also have strong power to kill viruses.

The new device is just a proof of concept. The researchers still need to turn it into a product that people will want to use. “There’s a lot of engineering to get from here to there, but every good idea needs to have a start.” says Steager.