【推荐1】Smart speakers have proven to be handy devices in hospitals, allowing patients to control independently . And now, researchers from the University of Washington have developed an artificial intelligence system that enables these devices to monitor heartbeats.

Using technology to remotely monitor heart rates isn't new. These days most smartwatches and fitness trackers are capable of it. The good thing here is that researchers have figured out a way to use the microphones in smart speakers to do it without requiring physical contact.

In a study published in Communications Biology, the researchers had the smart speakers send out signals that couldn't be heard which were then reflected off a person's body. They then analyzed these signals to identify small chest wall motions related to heartbeats, as well as separate those signals from surrounding noise and breathing.

For this particular proof — of — concept setup, the researchers tested this smart speaker on 26 healthy participants and 24 hospitalized patients with various heart conditions, including atrial fibrillation （心 房颤动）and heart failure. In both cases, the smart speaker was within 28 - 30 milliseconds of an ECG （心电图）,the gold standard used in hospitals to discover arrhythmia （心律不齐）.

Like smartwatches with advanced heart features, using smart speakers in this way opens up the possibility for passive, remote heart monitoring. ECGs, while highly accurate, require a visit to the doctor and several electrodes （电极）to be placed on the body. They^, re not capable of continuous monitoring so you're limited to what it picks up at that exact moment in time ——one reason why heart arrhythmia can be so hard to discover.

Smartwatches are capable of passive, remote, continuous monitoring, but they require you to wear the device at all times to be effective. It's not something that's comfortable for everyone, especially when it comes to sleep and for those with highly sensitive skin. Another issue is that these advanced smartwatches are expensive, while smart speakers are much cheaper.

“If you have a device like this, you can monitor a patient on an extended basis and then develop corresponding care plans that satisfy the patient' s needs,“ said Dr. Arun Sridhar, co — senior author on the study. "And the beauty of using this kind of devices is that they are already in people's homes.”

【推荐2】On paper, hydrogen looks like a dream fuel. In practice, things are trickier. Storing meaningful quantities of hydrogen gas requires compressing (压缩) it several hundred times. Transforming it into liquid state is another option, but one that requires cooling the stuff to -253℃. Either process requires rugged tanks. Over time, hydrogen gas can pass slowly into metals, weakening them and potentially causing cracks. Tanks must be built from special materials designed to resist this breakdown.

Researchers at the Fraunhofer Institute led by Marcus Vogt, think that supplying hydrogen as goop (糊状) offers a way around some of its limitations. They have been experimenting with a chemical compound that can be pumped into a container and then persuaded to give off its hydrogen on demand.

Their invention, which they nickname “powerpaste”, looks like toothpaste. Its main ingredient is magnesium hydride, a compound that when introduced to water, reacts with it to form hydrogen and magnesium hydroxide. The escaped hydrogen can then be redirected into a fuel cell, where it reacts with oxygen from the air to generate electric power. The magnesium hydroxide waste is emptied from the reactor automatically.

Dr Vogt’s scheme offers several advantages over batteries, petrol and more conventional ways of handling hydrogen. One is the storage of energy than either batteries or petrol can manage. A second is ease of refilling, which is simply a matter of swapping an empty container of paste for a full one, and topping up the water, which is stored in a separate tank. A third advantage is that, unlike a battery, the paste does not gradually lose its stored energy if it is left on the shelf. Moreover, the paste itself is harmless, as are the reaction’s by-products.

But there are still more to work through. Magnesium hydride reacts only slowly with water. To overcome this, Dr Vogt and his team have found a chemical additive that greatly accelerates the reaction. They have also found a way to ensure that the reaction can be controlled precisely enough to supply only as much hydrogen as is needed at any given moment.

【推荐3】Are your childhood memories closely connected with cycling? Perhaps you even remember the pride in getting your first bike on your birthday, complete with streamers (装饰彩纸条) coming out of the handlebars, and the excitement of coasting down the tallest hill in town? When we were children, biking gave us independence, a sense of self, adventure and excitement, but city biking poses challenges to us when we are adults.

Obviously, biking brings a number of benefits to the riders, but why aren’t there more bikers on city roads? Goodordering, a company that designs bags to suit modern active lifestyles, conducted a survey and found out that the number one factor preventing people from biking to work was the realization of road safety”—sharing the road with cars can be dangerous.

Omar Bakhshi, a UK-based developer, experienced this first-hand. A car brushed against him while he was cycling, leaving him with an injury that impacted his taste and smell for life. Bakhshi realized what happened to him wasn’t unusual. Because bikers often experience close encounters (相撞) with cars, Bakhshi set out to make the roads safer for urban cyclists to use.

His company, Tether, is launching a small sensor that goes on a bike’s handlebars. As the biker rides through the city, the device projects (投影) a “safety zone” of lights onto the pavement. The hope is that these lights will force car drivers to sit up and pay attention to the rules of sharing the road. If cars get too close to the biker’s personal space, the lights will start shining.

What makes Bakhsh’s device different from similar devices on the market is its smart features. Tether’s device collects data from close encounters with cars and then the data is organized into a central database. The data can be accessed by bikers to determine which streets are safer for cyclists and choose a route to avoid areas that have a large number of close encounters with cars.

【推荐2】China is one of the largest producers and consumers of watermelon in the world. And Wu Mingzhu, a schoolmate of Yuan Longping at Southwest Agricultural College in Chongqing in the late 1940s, is the unsung hero who has helped make this possible.

“It’s no exaggeration(夸张)to say that about 80 percent of more than 20,000 of China’s new seed types of watermelons and sweet melons at people’s dining tables everyday are the result of great efforts made by Wu and her team over more than 60 years,” said a colleague of Wu’s.

In 1955, Wu voluntarily went to work in Shanshan County, Turpan Basin in northwest China’s Xinjiang Uygur Autonomous Region where working conditions were hard. In 1958, Wu began to promote the modern technology of cultivating(种植)melons among farmers. However, the local farmers who were used to folk cultivation methods, didn’t seem to take kindly to that. With the help of a famous local melon expert, Wu opened up three acres of wasteland to plant melons according to scientific knowledge. When autumn arrived, local farmers found the melons Wu planted in a scientific way were particularly delicious. From then on, the farmers began to adopt Wu’s scientific growing methods.

Wu’s efforts to grow quality melons began paying off in 1973 when she went to the off-season breeding(培育)base in Hainan. She wanted to develop Hainan as a pilot area so that the south area of China could also grow melons, and realize the dream of three-matured or even four-matured melons. After numerous difficulties, finally in the 80s, the melon variety selected by Wu succeeded. Wu said, “In Xinjiang, there are thousands of science and technology workers like me. They have worked hard for decades on the frontline of agriculture. I’m just one of the ordinary ones.”

Now dealing with Alzheimer’s disease, Wu is often unable to recognize her former colleagues or even her family members who live by her side. But having worked day and night to breed new seed types since the 1950s, she can still remember her melon work.

【推荐3】A diet high in fats and sugars actually affects the parts of the brain that are important to memory and makes people more likely to desire for unhealthful food, says American psychologist Terry Davidson.

Davidson didn’t start out studying people’s eating. Instead, he was interested in learning about the hippocampus（海马体）, a part of the brain heavily involved in memory. He noticed something strange when he studied mice with hippocampal damage. They would go to pick up food more often than the others, but they would eat a little bit, then drop it.

Davidson realized these mice didn’t know they were full. He says something similar may happen in human brains when people eat a diet high in fat and sugar. If our brain system is damaged by that diet, that makes it harder for us to stop eating that diet.

The evidence is growing. In another study by Cambridge psychologist Lucy Cheke, her researchers asked obese（肥胖的）and thin people to do a memory task, a virtual treasure hunt. The subjects had to hide something in a scene across various computer sessions（会话框）, then they were asked what they hid, where they hid it and in which session. The obese people were 15-20 percent worse than the thin ones in all aspects of the experiment.

Cheke says with the link between obesity and the brain growing as a field of research, we could see more ways of targeting obesity. For example, if the problem is that obese peopled diet degrades their memory, perhaps making peopled meals more memorable would help them eat less bad stuff. Previous researches showed that watching TV while eating will probably make people eat more, get hungry in the afternoon and eat more at dinner. So Cheke suggests not watching TV while eating. It is one of the easy changes people can make that don’t involve much self-control, but that makes a great difference.