【推荐2】Loneliness is significant mental health concern and can raise risk of death by 45% and contact with nature in cities significantly reduces feelings of loneliness, according to a team of scientists.

The study is the first to assess how the environment can affect loneliness. It used real-time data, collected via a smartphone app, rather than relying on people’s memory of how they were feeling.

The research found that feelings of overcrowding increased loneliness by an average of 30%. But when people were able to see trees or hear birds, feelings of loneliness fell by 28%. Feelings of social inclusion also cut loneliness by 21％ and when these feelings coincided(巧合) with contact with nature, the beneficial effect was boosted by a further 18％.

The findings pointed to interventions to reduce loneliness. The researchers said, “Specific measures that increase social inclusion-and contact with nature should be taken, especially in thickly populated cities.” Time spent in nature is known to boost well-being, with woodland walks estimated to save the UK at least ￡185m a year in mental health costs, for example.

The research collected data from urban citizens across the world using the Urban Mind search app. More than 750 people provided 16,600 of these assessments. The participants were self-selecting and so it did not provide a representative sample of the wider populations. But when the researchers took age, education, and occupation into account, the benefits of nature contact and feelings of social inclusion on loneliness remained strongly statistically significant. Johanna Gibbons, part of the research team, said, “Cities are probably the only habitat that is increasing at a high rate. So we should be creating urban habitats where people can thrive(兴旺).”

【推荐3】We’re all familiar with songs getting stuck in our head while we’re awake, but it turns out this can happen during sleep as well. A new study investigating the phenomenon indicates that earworms invading (侵入) our brains at night could cause problems in getting to sleep and staying asleep.

“Our brains continue to process music even when none is playing, including apparently while we are asleep,” says neuroscientist Michael Scullin.

He and his colleagues used surveys of 199 people, as well as a sleep lab test involving 50 volunteers, to measure how listening to music before bedtime affects sleep. In particular, the team focused on catchy earworms. In the survey part of the study, participants who frequently listened to music during the day were more likely to report persistent nighttime earworms, which then had a negative effect on sleep quality through the night.

Earworms were reported throughout the night by participants, with those catching an earworm taking longer to fall asleep, spending more time in the light stages of sleep, and waking up more times during the night. Surprisingly, the instrumental versions of the songs caused about twice as many earworms and more subsequent sleep problems than the versions with vocals (声乐).

“We thought that people would have earwormns at bedtime when they were trying to fall asleep, but we certainly didn’t know that people would report regularly waking up from sleep with an earworm,” says Scullin. “But we saw that in both the survey and experimental study.”

Scullin suggests avoiding listening to music right before bed to limit the chance of a catchy tune taking hold in our minds. Engaging in some other cognitive activity before sleeping, like making a list of jobs for the next day, might also help clear the mind, Scullin says.

“The more you listen to music, the more likely you are to catch an earworm that won’t go away at bedtime. When that happens, chances are that your sleep is going to suffer.”

【推荐2】There is increasing alarm about the extent of microplastic pollution, which has been found everywhere from Everest to the Arctic. However, it turns out there’s an even smaller and more toxic form of plastic pollution entering remote reaches of the globe. A new study published in Environmental Research found significant quantities of nanoplastics in ice samples from both the North and South Poles.

“Now we know that nanoplastics are transported to these comers of the Earth in these quantities. This indicates that nanoplastics are really a bigger pollution problem than we thought,” study lead author Dusan Materic said in a press release.

Nanoplastics are plastics that are smaller than a micrometer in size. Their small size means they are more difficult to study than microplastics, or plastics between five millimeters and a micrometer. But they may be even more dangerous.

“Nanoplastics are very toxicologically active compared to, for instance, microplastics, and that’s why this is very important,” Materic said.   

Materic and his team used new methods to measure nanoplastic pollution in ice samples from Greenland and Antarctica. They sampled a 14-meter-deep ice core from the Greenland ice cap and sea ice from Antarctica’s McMurdo Sound. They found that there were an average of 13. 2 nanograms per milliliter of nanoplastics in the Greenland ice and an average of 52. 3 nanograms per milliliter in the Antarctic ice.

But what was even more surprising than the amount of nanoplastics in the remote ice was just how long they had sat there. “In the Greenland core, we see nanoplastic pollution happening all the way from the 1960s. So organisms, despite the lack of the solid evidence, likely all over the world, have been exposed to it for quite some time now,” Materic said.

The study also looked at the types of plastic present in the samples. Half of the Greenland nanoplastics were polyethylene (PE), the kind of plastic used for plastic bags and packaging. A quarter came from tires and a fifth were polyethylene terephthalate (PET), which is used for clothing and bottles.

【推荐3】In most situations, light helps us see. But when it comes to looking at the night sky, light is actually a kind of pollution. It prevents our view of some of life’s most striking sights: stars, planets, and even galaxies(银河系).

“When I was a little boy, I loved the night sky. I remember looking up and the sky was filled with stars. I became an astronomer because I was amazed by their beauty, ”says Robert Gent, “Now in most big cities kids can’t see the stars like I did.”

Normally, about 2, 500 stars are visible(可见的) to the human eyes without using any special equipment. But because of light pollution, you actually see just 200 to 300 and fewer than a dozen from some cities. Only one in three Americans can see our own galaxy with the naked eyes. Those people live far away from the lights of big cities, office buildings, and shopping malls.

Fortunately, there’s an inexpensive and useful way. If we shine lights down at the ground instead of up into the sky, and use lower brightness levels, we can save big amounts of energy and keep the beauty of the night sky. Many cities and towns have passed laws limiting(限制) lights at night, making sure enough shine for safety without creating much light pollution.

Light pollution affects more than our view of the heavens and can harm wildlife. Migrating birds(候鸟) sometimes fly over cities and become confused by the brightness, flying in circles until they drop from exhaustion. Sea turtles need dark beaches for nesting and won’t approach bright lights. Too much light at night may even affect human health. For all these reasons, researchers are working on ways to use lights only when and where they are truly needed. Everyone deserves to look up at the sky.