1 . The text from my son said it all: “Dad, there’s an article you were born to write that the world is finally ready for: Bring Back the Handkerchief!” As my son knows, there’s no “bring back” for me. For me, the handkerchief never left.

My mother raised me with several fixed rules. One was that a gentleman always has a clean handkerchief in his right rear pocket, a piece of simple cotton, roughly 15 inches square and less than four inches when folded. I was a dutiful son, but as a child, I had been wondering what it was there for. After 60 years, my body weight now feels wrong if I’m heading out of the house with an empty back pocket.

I am sure this habit has sometimes struck friends but in polite company nobody comments on somebody else’s business. Children like my kids think of my hankie ridiculously old-fashioned and they have their arguments. If you have to be prepared every day for allergies or a cold, why not choose a little packet of tissues, which saves you from that disgusting business of blowing your nose in the thing and then stuffing it back in your pants?

Point taken. But a handkerchief is more durable and has a far wider variety of uses. Can you grab the handle of a pot that’s boiling over with a Kleenex? Or do you recall the cases of skinned knees and drippy noses that hankie wiped? In fact, my wife gave me several new handkerchiefs as gifts. Neither of us can count the number of times her eyes have welled up at a movie, or, as happens, she’s needed to blow her nose.

Yet not even my mother could have anticipated the hankie’s new role as an Essential Public Health Appliance. All of us have learnt how hard it is to follow advice from medical experts about not touching your face. Here is an answer. Use your hankie. In case of emergency, your handkerchief can become a makeshift DIY mask that can be pulled over your lower face like a robber entering a bank.

And it will certainly give me the chance to lift my chin and look at my adult children through one eye, asking in her good-hearted way, “What do you have to say now, smarty-pants?”

2 . “THE ANT AND THE ZEBRA” sounds like the title of a Aesop’s fable. Like all good fables, this one has a moral, which is that tinkering with nature has unpredictable consequences. Unlike the Greek originals, though, this fable is real.

The story plays out in Laikipia county, Kenya. The characters include big-headed ants, an invasive species, the native acacia ants, these invasive ants have gradually been replacing, the whistling-thorn trees where both sorts of ants live, a cast of elephants, lions, zebras and buffalo, and Douglas Kamaru, a Kenyan biologist in the University of Wyoming. As Mr Kamaru reports this week in Science, the ant invasion has set off a complicated chain of consequences which has helped zebras at the expense of buffalo — thus illustrating a phenomenon called “trophic cascade”.

It works like this. Whistling-thorns have co-evolved with the local ants. The trees provide the ants with shelter and food, in the form of large, hollow thorns into which they produce nutritious nectar. The ants, meanwhile, protect the trees by seeing off the chief threat to them, the local elephants, which are not keen to feed on trees crawling with biting insects.

Acacia ants’ habitat are thickly carpeted with whistling-thorns. Big-headed ants, however, are not good at keeping the elephants at bay. The elephants move in and bite the trees, removing much of the area’s cover. That upsets the local lions, which often use this cover to hide when hunting zebra. To compensate, the lions switch to hunting buffalo, which are more dangerous, but less fleet of foot.

Mr Kamaru has put numbers to the process, too. In invaded areas, elephants break trees five to seven times as often as in uninvaded ones. And in those uninvaded places, zebra kills are almost three times as frequent as in the invaded ones. Indeed, between 2003 and 2020, as the big-headed ants have spread, the percentage of local lion kills where the victims was a zebra fell from 67% to 42%. Over the same period, the percentage of kills that were buffalo rose from zero to 42%. Whether the buffalo blame the ants for their misfortune, no one knows.

3 . Exhibitions of the British Museum in 2024

4 . With the fast development of astronomy, astronomers are eager to find a hint of the familiar: planets that resemble Earth. By pushing technology to the limits, astronomers are rapidly approaching the day when they can find another Earth.

The most direct approach is to take a picture of it with a telescope. However, a more effective way is to use “the Doppler technique”. This involves analyzing starlight for evidence that the star’s movement is affected by the gravitational pull of a planet. Nowadays, astronomers can tell when a planet is pulling its star by only one meter a second — about human walking speed. That’s enough to detect a giant planet in a big orbit, or a small planet if it’s close to its star.

Another approach is to watch a star for a slight dip in its brightness. This occurs when an orbiting planet passes in front of the star and blocks part of its light. At most, a tenth of all planetary systems are oriented so that these mini-eclipses (日食，月食) — called transits (凌日) — are visible from Earth. So, astronomers have to monitor a lot of stars to capture just a few transits.

The dream of astronomers is to discover a rocky planet roughly the size of Earth orbiting in a habitable zone, one that is neither too hot nor too cold to support life. If they succeed, they will have found what biologists believe could be a promising residence for life.

The best places to look may be dwarf stars. Smaller than the sun, dwarf stars are plentiful; seven of the ten stars nearest to Earth are dwarf stars. They also provide a steady supply of sunlight to any life-bearing planets within their habitable zone. Additionally, dwarf stars are dim, so the habitable zone lies closer in. If the planet is closer to the star, it’s easier for astronomers to detect a transit observation. A close-in planet also has a stronger pull on its star. That makes it easier to detect with the Doppler method.

7 . Optimism (乐观) is probably not a surprise that optimistic thinkers tend to be happier than pessimistic thinkers.     1     Here is what may surprise you.

Optimists live longer.

Optimistic thinkers have lower rates of high blood pressure, heart disease, and even risk of cancer, as well as lower rates of mortality in general. These health factors may be influenced by optimists’ focus on taking care of themselves.     2     One large study published in 2022 determined that optimists have a life span 11% to 15% longer than average.     3    

Optimists are more successful.

Just as optimists tend to be more resilient (有复原力的) outside of the workplace, they are also resilient on the job. Even if their bosses don’t recognize that they’re doing a good job, optimists are able to bounce back and keep performing well. People who are more optimistic also seem to have better job security than less optimistic workers.     4     Plus, people who feel optimistic about their careers are more likely to both succeed at work and to feel satisfied with their jobs.

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People with higher levels of subjective well-being — a mindset that can include optimism — have stronger immune systems and even experience faster wound healing than others with lower levels of well-being. People with positive experiences lowered their rates of depression, physical symptoms, and sleep complaints.

8 . Ordos Cultural Products Shine at Shenzhen Fair

A group of 10 exhibitors representing the city of Ordos, Inner Mongolia autonomous region, polish their products at the 19th China International Cultural Industries Fair in Guangdong province.

The fair is being held in Shenzhen.

It runs to October 21.

The Ordos exhibition area — themed “Meeting on the grassland, falling in love with the Warm City” — divides its 240 square meters into an immersive experience area, a cultural and tourism product exhibit and even an interactive activity area.

Nearly 300 featured handicrafts, cashmere products, personalized ceramics (陶器) and other cultural and creative products from Ordos amaze visitors. Meanwhile, the dance and traditional horse-head fiddle performances brought by the Ordos’ Ulan Muqir art troupe have been popular at the Inner Mongolia exhibition hall.

While showcasing the development achievements of the Ordos culture industry, the exhibition area also allows visitors to experience the charm of the city’s culture.

9 . One of the world’s greatest conveniences was born in its greatest hardships. Sylvan Goldman, a grocer from Oklahoma City, invented the shopping cart.

Sylvan Goldman was born to an immigrant pioneer family on Nov. 15, 1898, in what was then the Chickasaw Nation. His birthplace is now part of Ardmore, Oklahoma, about 100 miles south of Oklahoma City. His father, Michael Goldman, was born in Latvia. His mother, Hortense Goldman, came from Alsace-Lorraine.

Goldman learned the retail store business from working in the family dry goods store in Ardmore, Oklahoma, where he spent most of his life. He introduced his unique invention at his chain of Humpty Dumpty grocery stores across the state in 1937. He came up with design by placing a basket on the seat of a folding chair, and attaching wheels to the legs. The baskets had to be removed when the cart was folded, so they took up very little space. A year later, Goldman added a baby seat to his design.

“I thought it would be an immediate success,” Goldman said. “I went down to the store the next morning about 10 o’clock, expecting to see people standing in line outside the store trying to get in.” But he was met by utter disappointment. “When I got there, there was a large room for me to get in. There were people shopping but not a one was using the carts.”

Undaunted, Goldman turned to a classic marketing strategy. He employed women of various ages to walk around near the entrance of each store, pretending to be shopping with their carts. When shoppers had seen the ones that were walking around using the carts, they started using them. And immediately the carts became a huge success.

The invention, the grocery shopping cart, made Goldman a millionaire. It became one of the most-used items on four wheels, second only to the car. Goldman gave part of his fortune, $1.5 million, to the Oklahoma Blood Institute, whose Sylvan N. Goldman Center does lifesaving work. Goldman and his wife funded buildings for the center and provided support for education there.