【推荐1】Scientists learned recently that fish was the main source of protein for people in southern Scandinavia many thousands of years ago. They also ate other animals that live in the water. The findings come from Lund University in Sweden. Scientists there tested ancient human bones from more than 80 individuals.

One of the researchers was Adam Boethius. He said by studying the chemicals of the bones, they learned the diet of the people they belonged to.

Basically you are what you eat. And so when you study stable isotopes (同位素), you get a clue to what the humans have been eating.

The study examined the importance of a mix of protein sources in the human diet from around 10,500 to 7,500 years ago. They found that in Scandinavia most of what people ate came from the sea.

Boethius said back then, fish made up 50 to 70 percent of the diet. He said other sea animals like seals and dolphins brought that percentage to almost 100 percent.

This research changed the understanding of how ancient people of the area lived. Earlier studies suggested these people hunted big animals and moved around a lot to follow them. But the chemical examinations did not show proteins linked to deer and elk (麋鹿) and other land animals of the time.

Boethius said scientists now believe these people stayed in one place for most of their lives and ate local food. The discovery, he argued, provides evidence that settlements appeared in Scandinavia much earlier than researchers once believed.

【推荐2】Located in a comer of north Brooklyn is a 3,000-square-fbot patch of open space. Keap Fourth, at the intersection of Keap and South 4th Streets, is a community garden established in 2013. It’s a well-known part in this largely Dominican and Puerto Rican neighbourhood, at the edge of trendy Williamsburg. The sun is out, and “it’s nearly planting season,” says Crito Thornton, a volunteer who manages the garden, with a grin. After a long winter made worse by Covid-19 there are finally signs of life in the daffodils blooming around the garden.

Keap Fourth is one of 550 community gardens which have sprung up at New York’s street comers since the 1970s, when the city’s economy collapsed and its landscape became dotted by abandoned lots. Activists sought to transform these urban scars into gardens where residents could relax and grow vegetables. These places now cover 100 acres across the city, tended by a volunteer army of nearly 23,000 green-fingered New Yorkers. The gardens are supported by GreenThumb, a government initiative established in 1978, which is now the country’s largest urban-gardening programme.

Running these spaces is no easy task. Keap Fourth’s neighbourhood has been troubled by drug dealers, who moved across the Williamsburg Bridge after being driven out of Manhattan’s Lower East Side. The garden is a popular drop-off point, with suspicious packages found among the greens. But the recent death of a local kingpin (毒枭) in a car accident and the efforts of the police may make the gardens more peaceful, says Mr. Thornton.

The future looks bright. A key issue in the past has been a manpower shortage for the harvest. But volunteer numbers across the city’s gardens have gone up slowly since the pandemic’s onset, as locked-down residents have desired for more open space. And in Keap Fourth’s case, the whole neighbourhood seems to have come together over the past year as few people now undergo the daily commute (通勤) across the river to Manhattan. A bountiful harvest is in prospect.

【推荐3】Monarch butterflies(黑脉金斑蝶) are a common summer sight in the northern United States and Canada. These large orange and black insects brighten parks and gardens as they fly lightly among the flowers. What makes monarchs particularly interesting is that they migrate—all the way to California or Mexico and back. They are thought to be the only insect that does this.

Every year in the late summer monarchs begin their journey to the south. Those heading for Mexico go first for the Louisiana-Mississippi area, then fly across the Gulf of Mexico into Texas. Once in Mexico, they settle themselves in one of about fifteen places in a mountain forests filled with fir tress. Each place provides a winter home for millions of monarchs. The butterflies are so many that they often cover entire trees. When spring comes, they begin their long journey north.

The question is often asked whether every butterfly makes the round-trip journey every year. And the answer is no. The average monarch lives about nine months. So one flying north might lay eggs in Louisiana and then die. The eggs of that generation may be found in Kentucky; the eggs of the next generation may end up in Wisconsin or Michigan. The last generation of the season, about the fourth, will make their way back to Mexico and restart the journey.

Scientist learn about monarchs’ migration by catching and making marks on the insects. By recatching a monarch with such a mark and noticing where it came from, the next scientist can get to know things like the butterfly’s age and its routing.

【推荐1】An astronaut crew of private citizens has been launched to the International Space Station(ISS).The launch happened in Florida’s Kennedy Space Center. The flight is the first to be organized and operated by a private company involving a completely commercial astronaut crew.

The four-member team will travel to the ISS inside a spacecraft built by American company SpaceX. The crew members are from the private company Axiom Space based in Houston, Texas. The group is led by retired NASA astronaut Michael Lopez-Alegria. The mission is called Ax-1. Lopez-Alegria will be joined by the mission pilot, Larry Conner, a businessman and private pilot from Ohio. The other members of the crew are Israeli fighter pilot Eytan Stibbe and Mark Pathy, a Canadian businessman. Stibbe and Pathy will serve as mission specialists.

NASA says it will cooperate with Axiom mission officials to plan joint activities involving the Axiom team and regular ISS crew members. Currently, there are three American astronauts aboard the ISS, along with a German astronaut and three Russian astronauts.

The launch is being praised as a turning point in the latest expansion of commercial space activities. Such activities have become known in the industry as the low-Earth orbit(轨道) economy, or the “LEO economy”.

The latest mission’s crew might seem similar to private space tourists who recently took space rides that did not reach orbit. The trips aim to fly private citizens to the edge of space and permit them to experience weightlessness and observe Earth.

But Axiom executives(经理、主管领导) say their mission is very different. “We are not space tourists,” Lopez-Alegria says. The Ax-1 team will be carrying equipment and supplies for 26 science and technology experiments. They include research in areas including brain and heart health, cancer and aging.

Axiom’s co-founder and executive chairman, Kam Ghaffarian, says he saw the launch as “the beginning of many beginnings for commercializing low-Earth orbit”. He adds: “We’re like in the early days of the Internet, and we haven’t even imagined all the possibilities, all the capabilities, that we’re going to be providing in space.”