Humans have a way of understanding others’ goals, desires and beliefs, a crucial skill that allows us to anticipate people’s actions. Taking bread out of the toaster? You’ll need a plate. Sweeping up leaves? You’ll grab the green trash can. This skill, often referred to as “theory of mind”, comes easily to us as humans, but for robots it still has a high mountain to conquer.

In a recent study, computer science researchers made the robot “watch” the human complete the task using a camera placed directly above the assembly(组装)area, looking down. To detect the parts operated by the human, the system used AprilTags, similar to QR codes, attached to the parts. Then, the system used machine learning to learn a person’s preference based on their orders of actions in the task. “Based on how a person performs the small assembly, the robot predicts what that person will do in the larger assembly,” said Nemlekar. “For example, if the robot sees that a person likes to start the small assembly with the easiest part, it will predict that they will start with the easiest part in the large assembly as well.”

In the researchers’ user study, their system was able to predict the actions that humans will take with around 82% accuracy. “We hope that our research can make it easier for people to show robots what they prefer,” said Nemlekar. “By helping each person in their preferred way, robots can reduce their work, save time and even build trust with them.”This technology could also be useful in industrial settings where workers are tasked with assembling products in large numbers, saving time and reducing the risk of injury or accidents. Additionally, it could help persons with disabilities to more easily assemble products and maintain independence.

“Our goal is not to replace humans on the factory floor. I expect similar findings in other applications as well,” said Nikolaidis. “A robot that can quickly learn our preferences can help us prepare a meal, rearrange furniture or do house repairs, having a significant impact on our daily lives.”

Although the weather is very hot now, the carnival of ice and snow is getting closer. The preparation work for Beijing Winter Olympic Games, which are expected to begin on Feb 4, 2022, has entered its final stage. In January, 2021, the ice-making work on the “Ice Ribbon”, a landmark venue for the Beijing Winter Olympics, was completed.

In the Winter Olympics, where races can be won or lost by a small-time gap, tiny imperfections in the ice can make a big difference. “It’s not just a hunk of ice like you’d normally think of, like ice cubes sitting in your freezer,” told Kenneth Golden, a US mathematician who studies the structures of ice. “It’s a much more fascinating and complex substance than people would normally think.” ① ________

The first step for building any ice rink is to purify the water to remove dissolved (溶解的) solids like salts and minerals. Such impurities don’t fit in the regular hexagonal (六边形的) structure of ice that forms as water freezes. ②________ . The more pure the water is, the more consistent the ice surface.

③________. As one of the most advanced technologies for winter sports venues, a carbon dioxide (CO₂) cooling technology has been applied on a large scale for the Beijing Winter Olympic Games. CO₂ is not new when it comes to ice-making. However, it has been gradually replaced by the man-made refrigerant, like Freon.

With increasing attention toward climate change, the old refrigerant has come into use again. ④ ________ . As an element of the atmosphere, CO₂ doesn’t damage the ozone layer. Although CO₂ is a greenhouse gas, its greenhouse effect is much lower than that of other man-made refrigerants. The Winter Olympics venues adopted CO₂ instead of Freon as a refrigerant in ice-making, which will reduce carbon dioxide emissions.

“We believe these technological innovations will bring Beijing 2022 to spectators all over the world in a more impressive way,” told Gao Bo from the Media Operations Department of the Organizing Committee of the Beijing Winter Olympic Games.

Cloning is a technique scientists use to make exact genetic copies of living things. Genes, cells, tissues, and even whole animals can all be cloned.

Some clones already exist in nature. Single-celled organisms like bacteria make exact copies of themselves each time they reproduce. In humans, identical twins are similar to clones. They share almost the exact same genes. Identical twins are created when a fertilized egg splits in two. Scientists also make clones in the lab. They often clone genes in order to study and better understand them. To clone a gene, researchers take DNA from a living creature and insert it into a carrier like bacteria or yeast (酵母菌). Every time that carrier reproduces, a new copy of the gene is made.

In 1996, Scottish scientists cloned the first animal, a sheep they named Dolly. She was cloned by using an udder cell taken from an adult sheep. Since then, scientists have cloned cows, cats, deer, horses, and rabbits. They still have not cloned a human, though. In part, this is because it is difficult to produce a viable clone. In each attempt, there can be genetic mistakes that prevent the clone from surviving. It took scientists 276 attempts to get Dolly right. There are also ethical concerns about cloning a human being.

An embryo made by cloning can be turned into a stem cell factory. Stem cells are an early form of cells that can grow into many different types of cells and tissues. Scientists can turn them into nerve cells to fix a damaged spinal (脊髓) cord or insulin-making cells to treat diabetes (糖尿病). Livestock like cows and pigs have been cloned to produce more milk or meat. Clones can even bring a beloved pet that has died back to life. In 2001, a cat named CC was the first pet to be created through cloning.