【推荐1】After traveling through space for seven months, China’s Tianwen-1 has reached Mars and successfully entered the planet’s orbit on Wednesday—bringing it one step closer to landing on the surface.

Tianwen-1, which got its name from an antient Chinese poem, is made up of an orbiter, lander and a six-wheeled rover (巡视器) carrying scientific instruments, according to the China National Space Administration (CNSA).

The CNSA said the probe is expected to land on the planet’s surface in May or June, and the rover is expected to stay for three months, with the hope that it can gather important information about Mars’ geological structure, atmosphere, environment and soil, and search for any signs of water.

Tianwen-1 was launched last July, and its arrival in the Mars’s orbit makes China the sixth country in history to reach Mars. So far, the United States and the former Soviet Union are the only two countries to land a spacecraft on the surface of Mars. But the European Space Agency and India have already sent spacecraft to enter the planet’s orbit—and on Tuesday, the UAE joined their ranks, with its Hope Probe successfully entering orbit.

With Tianwen-1, China is the first nation to attempt sending both an orbiter and a rover on its first Mars mission on its own. According to the scientific team behind the mission, the probe will “orbit, land and release a rover all on the very first try, and carry out experiments with an orbiter”. By contrast, NASA sent multiple orbiters to Mars before ever attempting a landing, since pulling off the landing is a far more difficult task.

China’s first attempt to reach Mars was actually in 2011 with the Yinghuo-1 probe, which was supposed to orbit the red planet and study its environmental structure. It was launched from Kazakhstan together with the Russian Phobos-Grunt mission in November that year.

【推荐2】With new advances in AI and autonomous driverless cars and trains, it makes sense that this mode of transportation could be expanded to buses, too. Now a full-sized autonomous bus service is up and running in Scotland. The buses began running in May, 2023, and are carrying passengers between Ferrytoll Park and the Edinburgh Park train and tram exchange. This 14-mile route is the first of its kind in the UK.

The autonomous buses are being operated by Stagecoach, the largest coach operator in the UK. While the buses are autonomous, fully self-driving vehicles are not currently permitted in the UK so a driver has to be onboard at all times.

The vehicles are required to have a safety driver to monitor the technology and a bus captain that will help passengers board and purchase tickets. The driver can take control in case of an emergency situation. And the vehicles use sensors to travel on specific routes and can reach the top speed of 50 miles per hour.

It took almost 10 years of research and development to reach this milestone, which is considered the first full-size use of autonomous buses in Europe. Scottish transport minister, Kevin Stewart, said in a press release, “It’s really exciting to see the innovative and ambitious CAVForth project take to the roads after all the hard work of the partner organizations involved in bringing this world first to Scotland.” This project was one of six to receive funding from a joint UK government and industries undertaking to speed up the commercialization of self-driving technology, reported The Guardian. The government hopes the autonomous buses will be faster and more reliable to use than conventional buses since 88% of road accidents are caused by drivers’ errors.

Other countries in Europe are exploring using driverless buses. There have already been short trials in several cities in Italy, Finland and France and there’re plans for driverless electric minibuses to be introduced in Switzerland, Germany and Norway. An autonomous bus may be just around the corner in a city near you.

【推荐3】Many of the foods we regularly eat in our daily lives come from plants, which are essential for our survival on the “blue planet.” But what about the few people who live — although for a short span of time — in space? Is it possible for them to grow plants on board the spaceship and be self-sufficient for weeks on end? Yes, it is.

In fact, astronauts aboard the International Space Station (ISS) ate the first space-grown salad (red romaine lettuce) on August 10, 2015. Even in a well-controlled environment like on the ISS, growing a plant in space is not an easy task. Traditionally, roots grow and spread downwards due to gravity. Still, in space, where the effect of gravity is negligible (忽略不计的), things change.

Roots grow in all directions in space. Other nutrients and water, which are essential for the growth of a plant, float all over the place! Can you imagine a plant floating in a spaceship, with its roots sticking out in every direction like the tentacles of a slimy sea creature surrounded by water and other nutrients?

Therefore, keeping this entire system going is very important. To achieve this, NASA astronauts Rick Mastracchio and Steve Swanson set up a special container named “Veggie” a few years ago, specifically designed for “space gardening” on the ISS.

Veggie contains “plant pillows”, which are essentially bags of fertilizer and dirt released in a controlled manner to facilitate plant growth. In the bags, small wicks (棉芯) are installed that absorb water. Seeds are glued to the wicks and arranged in the correct position so that their roots grow unidirectionally (downward) and ‘push out’ of the bag. For the plants to grow properly (i. e. , upward), LED lights shine above the plants, provide light for the shoots and support photosynthesis (the process by which plants prepare their food) for proper plant growth.

Space agencies worldwide are striving to develop more advanced methods and procedures to enable astronauts to safely grow and eat vegetables from space-grown vegetables.

【推荐1】Chemists have spent the past century trying to make plastics that will break down in seawater. As it is, most plastics appear to take centuries to fully degrade in the ocean. But that may change. Scientists have just designed a new plastic that can break down in seawater within weeks, not decades or more.

Back in the 1930s, scientists created a now-popular plastic out of corn and potato starch (淀粉). It’s known as polylactide, or PLA. It’s a polymer (聚合物), which is a molecule made by linking many building blocks — called monomers — into a long string. Scientists had hoped PLA would quickly break down in the environment. And in some places, like compost pits (堆肥坑), it does. But not in seawater. Even after three years in ocean water, PLA remains largely unchanged.

Timo Rheinberger is a PhD student at the University of Twente in the Netherlands. His work on polymers has focused on boosting PLA’s breakdown. As part of that work, he became part of a team that just added some RNA-inspired breaking points to PLA. They put those breaking points in places where monomers in the PLA molecules are linked.

They weakened the links that joined up to 15 percent of a PLA’s monomers. Then, they soaked their samples in artificial seawater and measured how fast these tweaked versions of PLA broke down. The expected final product of PLA’s breakdown was a small molecule called lactic acid. So, they tested for that too.

As the team had hoped, seawater attacked the weakened links between monomers, splitting the polymer chain apart. The more breaking points the researchers added to the polymer, the faster the PLA broke down.

When they weakened 15 percent of PLA’s monomer links, the polymer broke down entirely within just two weeks. When they weakened only 3 percent of the links, the breakdown took about 2 years. This suggests the team can design how quickly PLA will break down in water by adjusting how many weakened links it has.

Mehlika Karamanlioglu teaches biomedical engineering at Istanbul Gelisim University. She, too, has studied environmental breakdown of PLA. “It’s a new approach,” she says of the Dutch technique. Theirs is also “a preliminary study,” Karamanlioglu says. So, more testing must follow. Scientists want to know how the strength of the new PLA compares to old PLA.

Rheinberger agrees. “You need a lot of material to start those studies,” he adds. And so far, his team has made only small amounts of the modified PLA.

Karamanlioglu notes the Dutch team also tested the breakdown of its PLA in artificial seawater. “I wonder if they checked [the water] for pollution,” she adds. If there were microbes (微生物), those microbes may have produced molecules called enzymes that sped up the PLA’s degradation.

【推荐3】A group of researchers has come up with a way to make it easier to drive in the snow: by designing tyres(轮胎)based on polar bear paws.

“We had an ongoing project for many years focused on ice,” said Ali Dhinojwala, who took part in the research. “We were looking at the friction(摩擦力)of materials because our national partners need to develop tyres with a strong grip on the road in ice and snow conditions.” The team turned to nature for inspiration, thinking that evolution might have already solved the problem in a way that could be copied with technology. The obvious place to look was polar bears—specifically the tiny bumps(凸块)on the surface of their paw pads—to find out what effect they have on the animals’ ability to move quickly across icy and snowy area.

To do this, the team gathered samples(样本)of polar bear paw pads, as well as samples from brown bears and American black bears(two species closely related to polar bears)and sun bears(a distantly related species, typically found in Asia).

The team imaged the samples using a scanning electron microscope, produced 3D-printed copies and then tested them in snow in the lab. They found that the tiny structures on the polar bear paw pads were taller, which gave them better friction on the snow, even though polar bears have smaller pads compared to other bears.

The team now wants to look into other factors that may have an effect, such as the patterns and shapes of the tiny structures. “If you look at snow tyres you’ll see that they do have some deeper treads(外胎花纹), but this research could also show various ways to design them that could have a larger impact,” said Dhinojwala.

【推荐1】Artificial Intelligence (AI) tools have become extremely powerful, surprising even their creators. Most people have probably read a book or seen a movie about an AI or robot that has become so smart that it can take over the world. The AI in stories like these is known as AGI or Artificial General Intelligence. True AGI would be intelligent in many different areas and would be able to learn on its own. Currently, there is no real AGI. Most experts believe it will be many years before an AGI could possibly be created.

Scientists have been working to improve AI models, mainly by training the models on larger and larger collections of information. Those efforts are paying off. The AI tool that has gotten the most attention recently is ChatGPT, created by the company Open AI. ChatGPT appears to be extremely intelligent, which answers quickly in perfect sentences, makes up stories and games, writes essays and much more. Another powerful model called GPT-4 is also developed by the same company. GPT-4 can create and explain jokes, and pass tests.

The rapid progress of recent A I models worries some people. Last week, many computer experts released a letter calling for a six-month pause in any work on AI tools stronger than GPT-4.

The letter claimed AI companies were in a race to create “powerful digital minds” that no one could “understand, predictor control”. The group behind the letter wants government s to develop laws to make sure A I tools are safe. Not all AI experts agree with the letter. Some say the letter makes today’s AI tools sound more intelligent than they really are. Others say it’s more important to worry about real problems in current AI tools rather than imaginary ones in the future.

ChatGPT has caused so much excitement that many companies are likely to keep developing powerful AI tools. But the letter has sent a strong warming that many people—including leaders—will be thinking about carefully.

【推荐3】A deep neural (神经系统的) network trained to restore ancient Greek texts can do so with 72% accuracy when used by historians, suggests a Nature paper. The findings could assist with the restoration and sort of newly discovered or uncertain inscriptions (碑文) with improved speed and accuracy, advancing our understanding of ancient history.

To understand the history of ancient civilizations, historians study the inscriptions created by past individuals, written directly on materials- such as stone, pottery or metal- that have survived until today. However, many inscriptions have been damaged over the centuries. Their texts are now vague and their date of writing is uncertain. Specialists in the study of inscriptions can reconstruct missing texts, but their traditional methods are highly complex and time-consuming.

To overcome the restrictions of current epigraphic methods, Yannis Assael, Thea Sommerschield and their colleagues tested a deep neural network (named Ithaca), a type of artificial intelligence (AI) that was trained to restore, date and place ancient Greek inscriptions. The authors found that Ithaca could achieve 62% accuracy when used alone to restore damaged texts, and 72% accuracy when it is used by a historian. Additionally, Ithaca could also help to determine inscriptions’ place and date of writing; in their experiments, it attributed inscriptions to their original locations with 71% accuracy and dated them to less than 30 years from the date ranges proposed by historians.

The findings could unlock the cooperative potential between artificial intelligence and historians, and improve our understanding of human history.

Common fields such as education, healthcare, catering, and industry have long been dominated by artificial intelligence, and this technology is now finding its way into relatively niche (小众) fields to more fully exploit its talents. Archaeology (考古学) is one of its latest fields.