【推荐1】To better understand the ocean’s overall health, researchers hope to utilize some simplest creatures as tools to assess aquatic ecosystems. All they need is stunning $20 worth of materials, a 3D-printer, and some natural jellyfish.

Although it’s extremely dangerous, technologically challenging, and expensive for humans to reach the ocean’s deepest regions, jellyfish do it all the time. Jellyfish first began dancing through Earth’s ancient oceans at least half a billion years ago, making them some of the planet’s oldest creatures. In all that time, however, their biological appearance has remained pretty consistent — a bell-shaped, brainless head attached to a mass of tentacles （触须）, all of which is composed of around 95 percent water. Unfortunately, that same steady state can’t be said of their habitat, thanks to humanity’s ongoing environmental impacts. “Since they don’t have a brain or the ability to sense pain, we’ve been able to cooperate with bioethicists to develop this biohybrid robotic application in a way that’s ethically principled,” a lead researcher of this study, John Dabiri said in a recent profile.

Previously, Dabiri’s lab implanted jellyfish with a kind of electronic pacemaker that controls the speed at which they swim. This time, the team went a step further, adding what they call a forebody to the jellyfish. It is like a hat that sits on top of the jellyfish’s bell. This 3D-printed, hat-like addition not only houses electronics and sensors, but makes its wearer even faster. In a specially built, three-story vertical aquarium, a jellyfish equipped with a combination of the swimming pacemaker and forebody can swim up to 4.5 times faster than its all-natural counterpart.

“It’s well known that the ocean is critical for determining our present and future climate on land, and yet, we still know surprisingly little about the ocean, especially away from the surface,” Dabiri said. “Our goal is to finally move that needle by taking an unconventional approach inspired by one of the few animals that already successfully explores the entire ocean.”By controlling their jellies’ vertical ascent and descent, Dabiri’s team believes the biohybrids could help gather deep ocean data previously obtainable only by using extremely price y research vessels and equipment.

【推荐2】Maybe you’ve wondered what you would hear if plants could speak. A stream of gossip from the roses? Wise whispering from the branches of an old tree? A faint, high-pitched cry of terror when your older brother takes out the lawn mower(割草机)?

Ariel Novoplansky, an ecologist in Israel, is studying how plants communicate with each other. To listen in, he set up a kind of telephone game among plants in his lab. Experiment used pea plants standing in rows of containers. The center plant in each row was the target: Scientists would stress out that plant and see whether the plants on either side of it picked up any alarm signals.

The pea plants had been grown with two main roots. On one side of the stressed plant, each plant had one root in its own pot and the other reaching into a neighbor’s pot. The central plant connected to its closest neighbor, which connected to another neighbor, and so on down the line. On the other side of the stressed plant, all the plants kept their roots in their own pots unconnected to their neighbors. Then the scientists dried up the soil of the central target plant, creating a drought.

Within 15 minutes, the dried-out plant reacted the same way it would in nature: it had closed up the tiny pores(气孔) on its leaves to save water. What’s amazing is that the central plant’s closest neighbor with connected roots had also closed up its leaf pores. And after an hour, the message had traveled down the whole row of connected plants. On the other side of the pea chain, where the plants’ roots weren’t connected, all their pores stayed open. This means the warning signal traveled from the stressed plant’s roots through the soil.

Dried-out roots aren’t the only talkative plant parts scientists have discovered. When sugar maple trees are damaged, they send signals through the air telling their neighbors to produce bad-tasting chemicals. When caterpillars chew on corn leaves, nearby corn plants also make more self-defense molecules(分子). The plants around us may not be speaking with any volume, but they are saying plenty.

【推荐3】Cork is a light brown material harvested from the cork oak tree. Cork is lightweight, strong and resistant to water.     1     For thousands of years, people have used pieces of cork as closures for bottles because cork is made of small cells filled with air. It is said that no technology has been able to copy this unusual material exactly.

The cork oak tree is native to the western Mediterranean coast of Europe.     2     In fact, Portugal produces more than half of the world’s cork supply. Cork oak trees have to be at least twenty-five years old before they are ready for harvest.     3     Cork is gathered by skillfully cutting off the outer layer of the tree with special knives. The harvest weakens the tree temporarily, but it soon starts to grow a new layer of bark. Next, the cork harvest is set out in the open for six months. Then, the cork is boiled in order to clean it and make it softer.     4    

Because cork oak trees are not killed during harvest, they can live for as long as 200 years. Also, used cork products can be recycled and used again. This makes cork a valuable renewable resource.     5    Wine makers say cork stoppers in their bottles let the wine be aged and improve over time. But now some wine producers are changing to plastic or metal closures. Some environmentalists worry that if cork starts to lose its value, the cork oak forests in Europe will no longer be protected.

【推荐2】A good meal has a positive impact on one’s mood. Those who feast on Christmas buffet almost enjoy an immediate rise in their blood sugar. That will prompt a flood of chemicals that act as happy hormones to rush through their brains.

But the pleasure goes deeper. Tyrosine and tryptophan are needed for the production, respectively, of dopamine, a neurotransmitter (神经传递素) that controls feelings of pleasure and reward, and serotonin, another such, which helps regulate mood. And cranberries are high in vitamin C, which is involved in converting dopamine to noradrenaline, another neurotransmitter, and a lack of which seems to be associated with depression.

With mental-health disorders rising, a growing number of scientists are investigating how food or nutritional supplements affect the mind. But separating the brain’s nutritional needs from those of the rest of the body is difficult. Not possible for now, at least. And, compared with other fields, nutritional science is understudied. That is partly because it is hard to do well. Randomised controlled trials (rcts), used to test drugs, are tricky. Few people want to stick to an experimental diet for years. Instead, most nutritional science is based on observational studies that try to establish associations between particular foods or nutrients and diseases. They cannot be used to definitively prove a causal ( 因 果 关 系 的 ) connection between a disease and a particular contributing factor in a diet. But as with smoking and lung cancer, put together enough of these kinds of trials and causal narratives begin to emerge.

It is now clear that some diets are particularly good for the brain. One recent study concludes that sticking to the “Mediterranean diet”, high in vegetables, fruit, pulses and wholegrains, low in red and processed meats and saturated fats, decreases the chances of experiencing strokes, cognitive impairment and depression. Other recent work looking at a “green” Mediterranean diet high in polyphenols found it reduced age-related brain atrophy. Another version, the mind diet, emphasises, among other things, eating berries over other kinds of fruit and seems to lessen the risk of dementia.

Scientists think such diets may work by reducing inflammation in the brain. This, in turn, may affect areas such as the hippocampus, which is associated with learning, memory and mood regulation—and where new neurons grow in adults. Studies in animals show that when they are fed a diet rich in omega-3 fatty acids (from walnuts, for example), flavonoids (consumed mainly via tea and wine), antioxidants (found in berries) and resveratrol (found in red grapes), neuron growth is stimulated and inflammatory processes are reduced. This fits with research suggesting that those who regularly eat ultra-processed, fried and sugary foods, which increase inflammation in the brain, heighten their risk of developing depression.