【推荐1】A team of researchers at Harvard University and Emory University have created a school of robotic fish. They can swim by recreating the contractions (收缩) of a pumping heart. Researchers say the experiment could advance pacemaker (心脏起搏器) technology and improve the development of artificial hearts for humans.

Researchers built the zebrafish-based fish using paper, gelatin (明胶), plastic fin, and two layers of human heart muscle cells. One ran along the robot’s left side, while the other along the right. When the muscle cells on one side contracted, the tail moved in that direction. This allowed the fish to swim in the water. The opposite side’s muscle cell layer similarly stretched as a result of the action. This stretching then sent a signal to the cells, causing them to contract, which kept the swimming motion going. The researchers also created an autonomous pacing node (节点), similar to a pacemaker, which controls the frequency and rhythm of these contractions.

The fish moved autonomously for over 108 days, equal to 38 million beats, the study stated. “Because heart cells constantly rebuild themselves, which takes about 20 days, the fish cells rebuild themselves about five times,” says Kit Parker, a professor from Harvard University who led the research. The fish eventually reached speeds and swimming efficiency comparable to wild zebrafish.

“Though the researchers say the fish is a step forward for heart research, it could be years before it leads to the creation of an artificial heart,” says Michael Schneider, a professor at Imperial College London, who wasn’t involved in the study. But that doesn’t dishearten Parker. “I think other methods will be faster than us,” says Parker. “But in the long run, creating tissue that relies on the patient’s own cells could offer unexpected benefits.”

【推荐1】On April 24th, police in California announced the arrest of Joseph DeAngelo. He stands accused of eight counts of murder. The starting-point of the arrest was genetic material recovered from the crime scenes. Though this directly matched no DNA held in a police database, analysis of it led investigators all the way back to the 1800s, to his great-great-great grandparents. The trail they followed links him to crimes committed around Sacramento in the 1970s and 1980s by an unknown man nicknamed the Golden State Killer.

That a link to distant ancestors could lead to an arrest proves the power of modern genomics (基因组学).

Investigators first uploaded Mr DeAngelo’s genetic profile ( 档 案 ) to a website called GEDmatch. This allows anyone to use his or her own genetic profile to search for family connections. GEDmatch’s database turned out to hold profiles, returned as weak matches, which looked as if they had come from distant cousins of the Golden State Killer. GEDmatch encourages uploaders to include their real name with their genomes, and the investigators were able to trace back through the matches’ parents and grandparents to find their most recent common ancestor. Then, having moved backward in time, they moved forward again, looking for as many as possible of this ancestor’s descendants. Using traditional newspaper clippings, census (人口普查) records and genealogy websites, they discovered some 25 family trees stretching down from the common ancestor. On its own, the tree on which Mr DeAngelo appears has 1,000 members.

From these thousands of descendants, the detectives found two suspects. One was eliminated (排除) from the investigation by further DNA tests of a family member. The other, Mr DeAngelo, was arrested after police had tested the DNA on an item he had discarded.

If a serial killer really has been caught using these methods, everyone will rightly applaud. But it bears on the question of genetic privacy—namely, how much right people have to keep their genes to themselves.

As the cost of genetic sequencing falls, the tendency of people to discover their own genetic information, rather than learning about it second-hand, will increase. That, though, may bring about a different problem, in which people obtain the sequences of others without their permission from things like discarded coffee cups.

【推荐2】Immersive cultural tourism has recently gained immense popularity, riding on the wave of consumer demand for interactive and engaging experiences.

“Immersive” has become a buzzword in recent years. It involves deep absorption in an environment or activity. It takes two primary forms: one constructs real or virtual worlds, transporting individuals into new worlds; while the other employs online platforms like livestreaming, videos, and augmented reality to immerse people in specific events.

Immersive cultural tourism is reshaping travel by offering deeper, more meaningful experiences that go beyond the conventional aspects of “travel, shopping, and entertainment”. It encourages in-depth exploration and interactive leisure, as demonstrated by various attractions.

In Xi’an, the Tang Dynasty Everbright City transports visitors to the magnificence of the Tang Dynasty, and the Tang Dynasty Treasure Box interactive game has gained popularity. In Yangzhou, the China Grand Canal Museum digitally showcases the Grand Canal’s history and culture, offering a comprehensive exploration experience. In Dunhuang, the Ancient Sound of Dunhuang allows visitors to explore mural paintings in an immersive manner.

These attractions breathe new life into traditional culture and present it in a fresh light. From a content perspective, immersive cultural tourism covers various cultural themes, including historical, revolutionary, and ecological aspects. These experiences immerse tourists in the past, present, and even the world of imagination. From a technological perspective, it makes use of innovations like 5G, high-quality screens, virtual reality and artificial intelligence, enabling visitors to engage in a storyline.

Immersive cultural tourism is transforming the way people travel by offering in-depth exploration, interactive experiences and meaningful learning opportunities. It promotes tourism from the shallow focus on sightseeing to a complete engagement with culture and history. Additionally, it plays an irreplaceable role in promoting cultural heritage, sharing China’s stories, enhancing cultural confidence, and fostering cultural development, making it a vital part of the travel industry.

【推荐3】The Mandarin（普通话）-speaking figure spins around a 360-degree restaurant scene in an artificial intelligence-driven instruction program that looks like a giant video game. Rensselaer Polytechnic Institute students testing the technology move inside the 12-foot-high projection（投影）to order virtual bean curd from the panda waiter, chat with Beijing market sellers and practice Tai chi by mirroring moves of a watchful teacher.

“Definitely less anxiety than messing it up with a real human being,” says Rahul Divekar, a computer science graduate student. “So compared to that anxiety, this is a lot more easy.”

The Mandarin Project is a joint enterprise of RPI and IBM. Cognitive and Immersive Systems Laboratory researchers are developing a sort of smart room that can understand students’ words, answer their questions and observe their gestures. Lessons are presented as games or tasks, like ordering a meal.

Divekar orders Peking duck-“Beijing kaoya”-and the panda fetches the virtual dish. Divekar says the food is good-“Cai hen hao chi”--but he can’t pay the bill. No problem, the panda replies-“Ni keyi xi pan zi”-you can wash the dishes.

Other scenes include an outdoor market and a garden, each a high-tech twist on cultural immersion.

“Our plan is to complete several scenes of real life in China, to let the student be able to have a virtual trip over there,” says Hui Su, director of the lab at RPI.

Tests on the room with students studying Mandarin will continue this school year as they work on additional scenes, including an airport. A six-week course is being readied for the summer.

The Mandarin Project is notable for its scale and complexity. Computers interpret speech and gesture to keep a dialogue going. When a student points to a picture and asks “What’s that?” computers can come up with an answer. Still, language teachers need not fear for their jobs just yet. Developers of the Mandarin Project say it isn’t advanced enough right now to completely replace classroom instruction.

RPI president Shirley Ann Jackson foresees the same type of technology being applied to other spaces, such as corporate boardrooms. “We’re not at the end of the line,” Jackson says, “but closer to the beginning.”

【推荐3】If this year’s turkey seems over salty, blame your brain.

The question of when saltiness becomes too salty is decided by a special set of neurons (神经元) in the front of the brain while a separate set of neurons in the back of the brain adjusts your appetite for salt, which the researchers showed in a series of experiments on mice.

“We are happy to drink sodas, sports drinks, and even tap water that contain a little salt. But if you imagine a very high concentration of sodium like ocean water, you really hate it. ”says Yuki Oka, an author of the study and a professor of biology at Caltech. This hatred to super salty foods and drinks holds unless your body is really low on salt something that’s pretty rare in people these days.

But experiments with mice found that when salt levels drop sharply, the tolerance for salty water goes up. The reason for this change involves at least two different interactions between the body and brain. When the sodium in the bloodstream begins to fall below healthy levels, a set of neurons in the back of the brain respond by dialing up an animal’s desire for salt. Meanwhile, a different set of neurons in the front of the brain monitors the saltiness of any food or water the mice are consuming. And usually, these neurons will set an upper limit on saltiness. But when salt levels get extremely low, the body sends a signal that is superior to these salt-limiting neurons, which allows mice to tolerate the saltiness of sea water.

The new study also found evidence that the brain cells involved in salt tolerance respond to hormone-like substances called prostaglandins. These substances, which circulate in the bloodstream, are best known for their role in causing inflammation, fever, and pain. Now it’s becoming increasingly clear that they also play a role in altering salt tolerance.

“Wars were fought over salt just a few centuries ago, and at least one previous effort failed badly, for a simple reason- awful taste.” says Stephen Liberles, a professor and Howard Hughes Medical Institute investigator at Harvard Medical School. “So finding a better option may require more than just research on how the brain monitors salt intake. Scientists also need to understand how that substitute will interact with our taste sense.”