【推荐1】Dogs greet other dogs nose-first, sniffing (嗅) each other from head to toe. People are not quite so open about the process of sniffing each other out. But the perfume industry suggests smell is important in human relations, too. There is also evidence that human beings can lead to close relationship, deduce (推断) emotional states and even detect disease via the sense of smell.

Now, Inbal Ravreby of the Weizmann Institute of Science in Israel has gone a step further. He think he has been able to prove, admittedly in a fairly small sample of individuals, that friends actually smell alike. He has also shown that with people picking friends at least partly on the basis of body odour (气味), rather than the body odours of people who become friends afterwards forming.

But why? To cast light on whether friendship causes a similarity in smell, or a similarity in smell causes friendship, Dr Ravreby investigated whether e-nose (electronic nose) measurements could predict positive interactions between strangers (new friendships often start from being strangers). To achieve this goal they gathered 17 volunteers, gave them T-shirts to wear to collect their body odours, ran these odours past the e-nose and then asked the participants to play a game.

That game involved silently mirroring another individual’s hand movements. Participants were paired up at random (随机) and their reactions were recorded. After each interaction, they show how close they felt to their fellow gamer by overlapping (部分重叠) two circles (one representing themselves, the other their partner) on a screen. The more similar the two smells were which are brought about by e-nose, the greater the overlap.

But why body odour might play a role in helping to form friendships remains unclear. Dr Rav re by theorizes that there may be “an evolutionary advantage in having friends that are genetically similar to us”. Body odour is known to be linked to genetic makeup. Smelling others may thus allow hidden connections about genetic similarity to be drawn.

【推荐3】During deep sleep, the brain appears to wash away waste products that increase the risk for Alzheimer’s disease.

A host of new research studies suggest that this stage of sleep-- when dreams are rare and the brain follows a slow, steady beat--can help reduce levels of beta-amyloid and tau protein, two characteristics of the disease. “There is something about this deep sleep that is helping protect you,” says Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley.

The research comes after decades of observations linking poor sleep to long-term problems with memory and thinking, Walker says. “We are now learning that there is a significant relationship between sleep and Alzheimer’s disease.” The strongest evidence involves deep sleep, he says. That’s when body temperature drops and the brain begins to produce slow, rhythmic electrical waves.

So Walker and a team of scientists set out to answer a question: “Can I look into your future and can I accurately estimate how much beta-amyloid you’re going to accumulate over the next two years, the next four years, the next six years, simply on the basis of your sleep tonight?” To find out, Walker’s team studied 32 people in their 70s who had taken part in a sleep study that looked for the slow electrical waves that signal deep sleep. None of the participants had memory problems. The scientists used brain scans to monitor levels of beta-amyloid in each participant for up to six years. And the results, published in the Nov.2 issue of the journal Current Biology, showed people who got less deep sleep had more beta-amyloid.

“We have a specific sleep signature right now that seems to help us better understand where you may sit on the Alzheimer’s risk track in the future”, Walker says. Other studies have found that a lack of deep sleep is associated with higher levels of tau protein, which forms harmful substances inside the brain cells and causes Alzheimer’s disease.

【推荐2】Over the past four decades, more than 450 butterfly species have been hit by the falling numbers. In the US alone, the number of monarch butterflies (黑脉金斑蝶) has seen a drop of 80%, from scientists recording millions of them in the 1980s, and only 29,000 in 2020. It’s part of a wider possibility across the insect group. In 2017, scientists in Germany raised alarm bells after finding that insects had fallen by more than 70% in 30 years.

For farmers, monarch butterflies pollinate (授粉) a very large percentage of food crops. It is very important t protect them because their disappearance could have a huge economic influence. Butterflies are also helpful in the coal mine for other insects, as it is easier for them to feel the environmental change. and relatively easy to record.

Leading environmental organizations have been working hard to find new ways of recording the number of butterflies. As of now, there is no long-term data to develop good protection methods. The scientists wanted to address the challenge that long term recording programs worldwide have faced: they are focusing on training locals as insect experts, which requires much money. They came up with a new method to the problem. In Yasuni National Park, they hired park rangers (护林员) who were trained and then carried out recording. The rangers were able to recognize butterflies with an 85% success rate, which is important for these kinds of recording programs to be successful.

Compared with other recording projects, this study represents a long-term solution. “Our method increases the chance of recording in the long term by reducing the money spent on it such as wages,” said lead author Maria Checa. “Furthermore, it also offers opportunities for public organizations to achieve their environmental goals.”

【推荐1】Mushrooms on a log may each seem like quiet, separate organisms, but they are actually the above-ground fruit belonging to a fungus (真菌)，connected to the large organism by a root network called mycelium (菌丝). Although mushrooms may not seem very talkative either, a new study shows electrical signals travelling through their mycelium network could help the organism communicate.

According to the research, some mushrooms can use electrical impulse (脉冲) to share and process information in their body. When signal activity increases, it creates complicated patterns that may function like words in human speech.

Previous research has found that mushrooms can send electrical signals underground through long, thread-like structures, which expand to form a network of mycelium. It works like nerve cells that send signals to other parts of the human body. Some studies have shown that electrical activity will increase when the mycelium of wood-digesting mushrooms touches blocks, which may indicate that mushrooms can use these impulses to share information about food or injury.

In the new study, four species were analyzed. Researchers listened to the mushrooms’ chat using tiny electrodes (电极) connected to mycelium to measure the power in signal activity. Each result in the activity was organized into several groups and given a linguistic (语言的) and information complexity analysis. The power varied in duration and length, with some lasting up to 21 hours. The electrical points resembled a human vocabulary of up to 50 words. However, only 15 to 20 mushrooms’ words are used frequently.

Mushrooms’ words are also similar in length to human words. The mushroom’s word length averaged over the four species is 5.97, which is of the same range as an average word length in some human languages. For instance, it is 4.8 in English and 6 in Russian.

While the research shows mushrooms can produce patterns of electrical signals, there’s no way to tell what they are talking about, if they are at all. Though comparing the mushroom’s electrical signals to human speech is interesting and notable, some researchers are doubtful. “Though interesting, the interpretation as language seems somewhat overenthusiastic and requires more research,” says Dan Bebber from the University of Exeter.

【推荐2】Yellow flower carpeted fields are a sure sign of summer. In Denmark alone, more than 200,000 hectares of rapeseed (油菜籽) are planted every year. But until now, the plant has only been used for oil and animal food, as it is both bitter and unsafe for human consumption.

To protect themselves, the rapeseed plants produce a group of substances (物质) called glucosinolates (硫苷), which give the plants a strong and bitter taste that scares off insects and disease. As a result rapeseed is unhealthy to eat and the rapeseed cake, which is the remains of the seeds after the oil has been squeezed out, has only been used as feed for pigs and chickens, despite its 30 — 40 percent protein content.

Now, researchers from the University of Copenhagen have discovered the three proteins that help to store the bitter substances in seeds of thale cress (阿拉伯芥), a plant closely related to the rapeseed. The new knowledge makes it possible to prevent the accumulation (积聚) of these substances in the seed by removing the proteins through “transport engineering” technology. In doing so, the defensive substances remain in all other parts of the plant, allowing it to continue to defend itself.

So far, the researchers have shown that their method works in thale cress. “The next task is to apply our method to the closely related rapeseed plant, which we are now working on,” says Professor Halkier, leader of the research.

“Half of plant proteins in the EU come from rapeseed. The climate crisis demands that we reduce meat consumption and eat more plants, which is where rapeseed has great potential as a new source of plant protein. Our latest research results bring us a step closer to making full use of rapeseed,” says Professor Halkier.

【推荐3】Baseball Plant

Where it's found: South Africa

This is a ball-shaped juicy plant. Unluckily, it was unsustainably harvested because more people around the globe have decided to grow baseball plants around them. Luckily, some botanical gardens have started to grow this plant. In this way, it will no longer need to be obtained from the wild so that it does not become extinct.

Corpse Flower

Where it's found: Sumatra, Indonesia

The corpse flower is also listed as an endangered plant and there are about 1, 000 plants growing in the wild. This plant sends out a smell of rotting（腐烂）meat during its nightly peak bloom. This allows it to attract pollinators like flies from miles away. It can grow an astonishing eight feet tall and can weigh up to 170 pounds.

African Starfish Flower

Where it's found: Botswana, Namibia, South Africa, Zimbabwe

Don't fall in love with its beautiful flowers, because this is yet another plant that's known for its bad smell. It smells like rotting meat and looks like a rotting animal! Unluckily, it is endangered due to destroyed habitats, plant collectors as well as the Zulus, who use the plant as a cure for hysteria（癔病）.

Hydnora Africana

Where it's found: Botswana, Namibia, Swaziland, Ethiopia

This has an appearance similar to mushroom until the flower opens. At this point, the plant transforms from a leafless brown-gray plant to something that looks more like an animal than a plant. While this is also a smelly plant, it is an edible（可食用的）fruit that is loved by many animals and even humans! It makes for a tasty food when mixed with cream and can also treat conditions like diarrhea（腹泻）.