【推荐1】For thousands of years, humans have used names to communicate with one another. We also give names to animals, especially ones we love, such as pets. Until now there has been little evidence of animals naming one another, but a new study suggests that elephants use specific noises to identify other elephants.

A few animals, including parrots and dolphins, have been known to use sounds that are similar to names. Each dolphin invents a signature whistle that is unique to it, and other members of its species communicate with it by simulating this special call. The new study, led by Michael Pardo of Colorado State University, shows that wild African elephants use names in a way that is not just copying sounds and is much closer to the way humans use names.   

For the study, the researchers recorded 625 sounds made by wild African elephants in Kenya that they called "rumbles (隆隆声)”. This is the most common type of call produced by elephants, and it can travel long distances-as far as 3. 7 miles. It takes place at a very low frequency, which means humans can't hear it.

The researchers analyzed the sounds using computers and found that certain rumbles were directed at specific elephants to get their attention They found that all the elephants in the herd used the identical call to get a particular elephant's attention -these calls were not just nicknames used by one of the elephant's friends. Also. unlike the way dolphins communicate. the rumbles were not just imitations of the elephant they were trying to communicate with.

The researchers then played back some of the recorded rumbles to the elephants. They found that elephants responded more to their own name than to other calls. coming toward it more quickly or calling back faster. Cartlin O'Connell-Rodwell, an elephant expert, said, "The study shows that elephants can still keep in touch with one another even across a large area. "She told Live Science, "The rumbles ere magical, which allow them to spread out much further and still have very close tabs（密切关注） on individuals. "

【推荐2】New research suggests that even a simple exercise program might help older people with light memory problems. Doctors have long advised patients to do physical activity to help keep their brains healthy. But the U.S. government-supported research marks the longest study of whether exercise makes any difference once memory starts to decline.

Researchers found around 300 inactive older adults with memory changes called mild cognitive impairment (MCI) (轻度认知障碍). In the research, the participants were divided into two groups and half of them did aerobic exercises, while the rest did stretching and balance movements that raised their heart rates a little. After a year, testing of mental activity showed neither group had worsened, said lead researcher Laura Baker of Wake Forest School of Medicine. By comparison, similar MCI patients in another long-term study of brain health — but without exercise — experienced cognitive decline over a year.

Maria Carrillo is the Alzheimer’s Association chief scientific officer. She said earlier research has found regular physical activity of any kind may reduce damaging inflammation and increase blood flow to the brain. She added that the new study is especially interesting because the COVID-19 pandemic began halfway through the study. That meant the study participants became socially isolated. Social isolation has long been known to increase people’s risk of memory problems.

It is a difficult time for dementia (痴呆症) research. Doctors are not sure about prescribing (开处方) a high-priced new drug called Aduhelm. The drug is supposed to be the first to slow the progression of dementia but it is not yet clear if it really helps patients. Researchers last month reported another drug that works similarly failed in an important study. There is growing urgency to find whether exercise might offer at least some protection. Baker will lead an even larger study of older adults to see if adding exercise to other steps such as a healthy diet, brain games and social activities may reduce the risk of dementia.

【推荐2】Along Route 1, in Thomas-tomatines a store filled with handicrafts—birdhouses and dollhouses, salad bowls and sailing ships — all made in Maine state prisons. Ted and Barbara Waylayer have been shopping here for decades. “We found the quality to be excellent,” said Ted.

Prisoners have been making things in Maine since the 1800s. Charlie Jones came here when he was 20, sentenced to 75 years in a state where there is no parole(假释). In the workshops, he discovered he had a talent for carving. One of Jones’ earlier projects was a golden eagle, which he learned to carve from a book.

“It’s amazing to see the amount of talent that the residents have here,”said Randall Liberty, commissioner(局长)of Maine’s Department of Corrections.“We have more than 100 residents working here daily. They do about US $1.6 million worth of work. “One of Maine’s programs allows residents to earn a college degree. The money for it was donated by Doris Buffet, who lived in Dockland, Maine. “She gave us an initial US $2 million donation,” said Liberty.   “And that’s the best money I’ve ever seen invested in anyone.”

Charlie Jones is one of the graduates. “The college program is incredible,” Jones laughed. “When we used to walk to dinner, we could hear people talking about their former crimes. But now when going to dinner, you’ll hear somebody talking about their philosophy class or their history class.”

Liberty said, “The individuals that graduate have about a 5% recidivism(再犯) rate, as opposed to a 60-65% nationally. That means 95% of the people who go through this program don’t go back.”

When Doris Buffet died in 2020, Charlie Jones made a table, with legs made of books, to honor her. It’s also carved with the names of courses open to prison residents, and the professors who teach them. On the table was a book telling Daris Buffet’s story, and a thank you note.

【推荐3】There will be more plastic than fish in the world’s oceans by 2050. That is what a new report from the World Economic Forum and Ellen MacArthur Foundation warns. If the current trend continues, the report said, oceans will contain one ton of plastic for every three tons of fish in 2025. By 2050, plastics will weigh more than fish. The problem is that each year at least 8 million tons of plastics end up in oceans around the world. This is the same as dumping the contents of one garbage truck into the ocean every minute.

Not all plastic ends up in the ocean because someone throws a plastic bottle into the water. Plastic containers and other trash thrown onto streets and sidewalks often are swept into oceans. Unlike other types of trash in the ocean, the plastic never bio-degrades. There is a way to slow the amount of plastics going into the oceans — people can recycle more. Currently only about 14 percent of plastics are recycled. Research in Europe shows as much as 53 percent of plastic could be recycled using available technology. The report says that another solution is using less plastic for packaging products. But that is not likely to happen.

“Given plastic packaging’s many benefits, both the possibility and desirability of an across-the-board dramatic reduction in the volume of plastic packaging used is clearly low, ”the report said. But the authors note reducing the use of plastics should be tried“where possible. ”For decades, scientists warned that plastics are killing fish. Research shows that fish are dying from choking after eating plastics. Another cause of death is that plastics cause“intestinal blockage and starvation, ”the environmental group said.