2 . Humans spend about one third of their lives sleeping. But some mammals (哺乳动物), like the northern elephant seal, survive with much less sleep.

Researchers in a new study described the unusual sleep pattern of these ocean animals. They found that when these mammals go to feed on trips that can last seven months, they sleep just two hours each day. Those two hours of sleep are made up of short moments of rest lasting only 10 minutes each as they dive deep to avoid predators (捕食者). The only other mammals known to get so little sleep are African elephants.

The researchers placed a head covered with sensors on the heads of the seals that they studied. The sensors recorded sleep signals created by the seals’ brains and heart rate. The sensors also recorded the animals’ location and depth beneath the sea.

The researchers studied female seals because they go out on long open-ocean trips while males feed in coastal waters.

During dives lasting about 30 minutes, the seals went into a deep sleep called slow-wave sleep while keeping a controlled downward movement. When they then experienced rapid-eye-movement (REM) sleep, the seals fell into a turning pattern. Then, at the deepest point of their sleeping dive — up to 377 meters deep — they wake up and swim back to the surface.

Terrie Williams is a scientist at the University of California at Santa Cruz who helped write the study. She said, “It is remarkable that a wild animal will fall into deep, paralytic REM sleep when there are predators on the hunt.” She added that the seals solve this problem by going into deep sleep in the deep parts of the oceans where predators usually do not hunt them.

Williams said the brain’s ability to control awakening the sleeping seals at a depth before they drown is also a discovery about how mammalian brains work. She commented on this saying that it shows the survival control of the seals’ brains.

4 . At Phoenix Bikes, a bicycle shop, students are learning to repair bikes. Phoenix Bikes sells bikes to the public at their business in Arlington, Virginia. But it also teaches teenagers how to repair bikes.

Most students at Phoenix start in its after-school “earn-a-bike program,” at middle and high schools in and around Arlington County. Once a week over a 12-week period, students learn repair skills. They learn how to use tools, fix flat tires, correct the wheels, and change gears (齿轮). The first lesson includes taking the bike apart. By doing this, they learn all the parts of a bike.

In the first few weeks, they work in small groups to repair a bike given to the shop. The bikes often have missing or damaged parts. The finished bike is then given to a person in need from the community. In the last four weeks of the program, students come to the shop to work on one of the given bikes which they can then take home at no cost.

Anthony is a student at nearby Wakefield High School. He just completed his bike. He said it was not in good shape at first but was the kind of bike he was looking for and could be made into something better. He said it had no lights, no front tire, and was without a chain, which controls the gears. He said he joined the program to get better at working with his hands and fixing things.

Phoenix Bikes is teaching 300 to 400 young people this year. Phoenix communicationscoordinator Gage said the classes are fun and let students learn with their hands after sitting in the classroom all day at school. He added that bikes are interesting for teenagers especially because they are a means of transportation and freedom. Learning how to fix a bike can also be a fun challenge, she said.

7 . “Do what you love, not what others tell you is right,” says Georgia Lines of New Zealand.

I spoke with the 24-year-old singer-songwriter earlier this month about her rise to fame. In 2022, Lines was named breakthrough artist of the year at the annual Aotearoa music awards ceremony. Aotearoa is the Māori name for New Zealand, an island country in the Pacific Ocean that is home to more than 5.1 million people.

Lines makes success look easy, but she has worked hard to perfect her skills. “I love what I do,” she told me. “I love it when I get lost in the music, and everything works together.”

Already, Lines has opened for pop singer George Ezra. She hopes “to open for Harry Styles one day,” she added.

Lines has written more than 20 songs and worked together with several top artists, including Jack Burton, Alex James, and Cassie Henderson. “I love working with other people and cooperating,” Lines said. “I find I work better when I’m with others so we can bounce ideas off each other.”

When asked about her musical ambitions growing up, Lines smiled. “I was never a musical genius as a child,” she said. “But I always loved singing and music.”

In recent years, Lines has drawn enthusiastic crowds for her concerts. The video for her hit song, “No One Knows”, won best music video of the year in New Zealand in 2021.

As for her future goals, Lines said that she wanted “to have a sustainable (可持续的) career and to keep doing what I love.” That means, focusing on her own career and artistic achievements. “Comparison is the robber of success,” she said. “If I had stopped to compare myself with others, I wouldn’t have made it as far as I have.”

8 . In February, the U. S. stated that its Mars explorer, Perseverance, landed successfully on the Red Planet. Perseverance is on a task to collect Martian soil and rocks as part of a search for signs of ancient life.

Perseverance landed in an area of Mars called Jezero Crater. Scientists believe the area has a large ancient lakebed. NASA considers the area a promising place to find possible signs of microbial life.

Perseverance carried to Mars a small experimental helicopter (直升机) named Ingenuity. In April, NASA said Ingenuity had successfully completed a takeoff and landing on the planet. It said the flight was historic; it marked the first time any flying machines had performed a powered, controlled flight on another planet.

In July, British billionaire Richard Branson entered into space on a rocket plane built by Virgin Galactic, the space tourism company he created. Branson joined two pilots and three other task experts on the flight. Virgin Galactic aims to fly private citizens to the edge of space to experience a few minutes of weightlessness and observe Earth.

A little over a week later, American billionaire Jeff Bezos flew to the edge of space on a rocket built by his company, Blue Origin. Three other people took the quick trip with him: Bezo’s brother, a Dutch teenager and an 82-year-old pilot.

The flights by Branson and Bezos officially started a new industry that promises any citizen the chance to visit space. Such trips will be costly, however. Virgin Galactic’s price for a single flight is $250,000. Blue Origin has not publicly announced its price. Both businesses have built operating bases, called “spaceports”, in the countryside areas of the U. S.

And earlier this month, Japanese billionaire Yusaku Maezawa arrived for a 12-day stay at the International Space Station (ISS). The businessman arrived along with an assistant aboard a Russian Soyuz spacecraft. The price of that trip has not been made public, but some reports guess it costs up to $50 million.

9 . This winter, the U. S. state of California received unusually large amounts of rain and snow. Now, people worry that some areas will flood as the snow in the Sierra Nevada Mountains melts (融化).

Ron Caetano lives about half-way between the cities of Los Angeles and San Francisco. He is preparing to leave in case his community, called the Island District, floods.

More than 100 years ago, the Island District area was under a large lake named Tulare Lake. At one time, Tulare Lake was the largest freshwater lake west of the Mississippi River. But reservoirs (水库) and watering systems for agriculture caused it to disappear. However, in very rainy years, farmland can still get covered with water.

Experts say reservoirs near the area will likely receive three times more water than they can hold this year. That means officials must increase the amount of water they release (释放) from the reservoirs. If too much water is released, the area might flood.

The Island District has organized a community network to help prepare for floods. People are placing sandbags close to elderly neighbors’ houses to block possible flooding. And they are looking at reports from water officials, county officials, and from each other.

California has had very dry weather in recent years. Both cities and farm communities acclaimed this year’s winter rains. If the weather gets warmer slowly, the snow will not melt quickly and there may be little or no flooding. But if the weather gets hot quickly, that will bring trouble from too much melting snow.

Officials announced plans to close parts of Yosemite National Park because of threats of flooding. The park is about 270 kilometers east of San Francisco in the Sierra Nevada Mountains.

Nicholas Pinter is with the University of California, Davis Center for Watershed Sciences. He said the lake’s size has always changed because of California’s weather. He described the surrounding area this way. “It has been an engineering problem all along,” he said. “This is a bathtub (浴缸) with no way out.”

10 . More scientists are exploring cellular senescence(衰老)—a state in which cells(细胞)no longer divide. Senescent cells, which build up in older bodies, have a link to age-related conditions such as dementia(痴呆) disease.

Scientists are exploring drugs that treat senescent cells. But the most promising tool against the bad effects of senescent cells, experts say, is exercise.

Today, LeBrasseur, who directs a center on aging at Mayo, says exercise is “the most promising tool that we have” for good health in late life, and its power spreads to our cells. Research suggests exercise prevents the buildup of senescent cells, helping the immune(免疫的)system clear them and fight the cell damage that can affect aging.

Last year, LeBrasseur led a study that provided the first sign in humans that exercise greatly affected senescence. It cut signs in the bloodstream of the effects of senescent cells in the body.

After a 12-week exercise program, researchers found that older adults had cut signs of senescence and improved body strength, physical ability and reported health.   A recent study collects even more facts—in animals and humans—for exercise as a treatment to fight against senescence cells.

While such studies are not well-known outside scientific circles, many older adults connect exercise with youthfulness. Farmer Mike Gale, 81, put in a track and field throwing circle on his large farm in California. He and some of his friends throw the discus(铁饼) and use other exercise equipment. “I'd like to be competing in my 90s,” Gale says. “Why not?”

95-year-old Richard Soller says exercise keeps him fit enough to deal with what comes his way—including the discovery that his wife of 62 years had developed dementia. The two sometimes walk the streets of their neighborhood together, holding hands. “Do as much as you can,” he says. “That should be the goal for anyone to stay healthy.”