1 . You know the feeling — your ears start to warm up, your tongue goes numb, you start sweating and taking deep breaths. You know eating something spicy would be painful, but you choose to do it anyway. Are humans just masochistic (受虐狂的), or is there something else going on? The answer lies in both science and history.

Let’s start with the science. Spicy isn’t actually a taste like salty, sweet, sour and bitter — it’s a sensation(感觉). This sensation is caused by a chemical compound in chili peppers called capsaicin (辣椒素). When we eat foods containing capsaicin, our bodies are tricked into thinking the temperature is rising. In trying to temper the burning sensation, our bodies release endorphins, which control pain and, at the same time, give a feeling of pleasure.

This is what is happening chemically, but there is also a conscious side to choosing spicy food. Dr. Tamara Rosenbaum, a cognitive neuroscientist, explains that this is because we are rational beings — we know that the burning sensation of chili does not physically harm us. Furthermore, we get pleasure from the other ingredients(成分) chili is generally cooked and eaten with — including fat, sugar and salt.

This masochistic relationship with capsaicin has been long, starting in the Andes of South America, where chili peppers originate. Humans were among the few mammals on Earth that developed a taste for capsaicin. Archeological evidence suggests that humans started cultivating chili peppers about six thousand years ago. Human intervention(介入) changed the chili pepper to suit human tastes and needs — including the pepper’s color, size and capsaicin content — helping to explain the many different types of chili peppers now available.

Fast-forward to today, and our love affair with the chili pepper is going strong. We eat around 57.3 million tons of peppers globally each year, and chili is a key ingredient in traditional dishes from Mexico to Korea. Maybe we are masochistic, after all.

3 . Listening to birds and water can lower stress and improve mood, study finds. Researchers have long known there are benefits from being in nature. Living around trees can help you live longer. Walking in the woods is good for your mood. Being near water can have positive effects on your well-being.

A new study finds that natural sounds offer health benefits too. There is plenty of evidence that spending time in natural areas is good for our health — but typically this research is done from a visual perspective, but we are curious what the role is of sounds we hear in these spaces.

Some examples they found reported in those studies included decreased pain, lowered stress, improved mood, and better cognitive (认知的) function. With these results in hand, they then listened to audio recordings from 251 sites in 68 national parks across the United States.

The sites with the most natural sounds and the lowest man-made sounds were located in Alaska, Hawaii, and the Pacific Northwest and were far from urban areas. Only three locations with high natural sounds and low noise pollution were within 100 kilometers (62 miles) of urban areas.

However, despite human-made noises being heard most of the time at sites in urban locations, birds were still heard about 60% of the time and geophysical sounds like wind and rain heard about 19% of the time.

Not all natural sounds deliver the same benefits, the researchers found. For example, they discovered that the sounds of water had the largest impact on improving positive emotions and health outcomes, while bird sounds ease stress and annoyance. And the sounds of both birds and water were heard more than 23% of the time in the national park recording sites.

Interestingly, there was also some evidence that natural sounds have benefits over silence. There was also evidence that more different types of natural sounds — more types of birds singing rather than just one type of bird— have benefits over fewer sounds.

4 . Healthy eating doesn’t just mean what you eat, but how you eat.     1    

Eat with others. It can help you to see others’ healthy eating habits. If you usually eat with your parents, you will find that the food you eat is more delicious.

Listen to your body.     2     Have a glass of water to see if you are thirsty (口渴的). Sometimes you are just thirsty and you don’t need food. Stop eating when you feel full.

Eat breakfast. Breakfast is the most important meal of the day. After you don’t eat for the past ten hours, your body needs food to keep you going.     3    

Eat healthy snacks like fruit, yogurt or cheese.     4     In fact, it’s a good idea to eat two healthy snacks between your three meals. But this doesn’t mean you can eat a bag of chips instead of a meal.

Don’t eat dinner late. With our busy life, we always put off the dinner time until the last minute.     5     This will give your body a chance to digest most of the food before you rest for the next 8 hours.

8 . There are all electric cars, boats, trains, and small planes that are a sustainable way to travel. Larger airplanes have not been able to make the transition because the lithium-ion (锂离子的) batteries are too heavy and not strong enough to provide the power for the airplane to take-off.

NASA is working on a new innovative solid-state battery that can be used by the aviation (航空) industry. The batteries, called Solid-state Architecture Batteries for Enhanced Recharge ability and Safety (SABERS) do not suffer from any of the limitations of lithium-ion batteries and can outperform the batteries that are available now.

The solid-state batteries that NASA researchers are working on carry more energy, and are considerably lighter, and much safer to use. That’s because solid-state batteries do not contain liquids which can lead to overheating, fires, and charge loss.

Battery performance is the key to making aviation sustainable and practical. The batteries must be able to store large amounts of energy without being too heavy. And the battery must be able to rapidly release that energy. That’s where solid-state technology comes in.

Liquid batteries require each cell to be inside its own steel casing. Solid-state batteries can be stacked in a single casing and that reduces the weight. The battery can also run at much higher temperatures that require much less cooling. All of this makes NASA’s new battery very promising.

Now that NASA has demonstrated the new battery’s properties, the agency is looking at all its potential uses. SABERS is cooperating with researchers from Georgia Tech. “Georgia Tech has a big focus on micro mechanics of how the cell changes during operation. That helped us look at the pressures inside the battery, which then helped us improve the battery even more,” Viggiano said in the news release. “It also led us to understand from a practical standpoint how to make a cell like this.”

He added that SABERS has grown from an idea discussed around a lunch table to a possible solution for sustainable aeronautics (航空学). A fully electric airplane is more likely to appear on the market.

9 . Have you ever seen your cat or dog eating grass? They do so because it can help their digestion, and many wild species use natural substances to prevent and control diseases. This is called “zoo pharmacognosy” or, more commonly, animal self-medication.

Scientists have discovered that tamarin monkeys use a specific tree resin (树脂) as medicine. In the Brazilian Atlantic Forest, scientists followed several groups of them to collect data. During one of these daily studies, tamarin monkeys were observed rubbing their bodies on the trunk of a tree. At first, researchers thought that they were marking their territory, a common behaviour in this species. Botanical experts later confirmed that the tree was a species of cabreuva, which is well known for its medical properties.

Researchers decided to place camera-traps in different sites at the foot of the tree to record future visits by tamarin monkeys. The records surprisingly showed that many animals living in the forest visited it. Totally, ten species were observed. For many of them, it was the first time that behaviors similar to self-medication had been observed. More surprisingly, one species spread resin on each other’s fur in pairs. In general, the species seemed to specifically visit the tree to acquire the resin and seemingly benefit from it, either healing their wounds or fighting back parasites (寄生虫).

While further studies are needed to identify the properties of the resin and thus confirm that this is indeed self-medication, the use of it suggests that cabreuva represents a common and universal drugstore for the residents of the Brazilian Atlantic Forest. It is likely to be a valuable resource helping the species maintain their magnitude by improving their health.

This discovery could have an important protection influence, as the disappearance of some trees could potentially affect the survival of some animals.