1 . To solve a big environmental problem, chemists in the Czech Republic have been thinking small. Really small. Their new minirobot has one purpose: to help clean up tiny bits of plastic polluting waterways across the globe.

Each new robot is no bigger than the tip of a sharpened pencil. They are magnetic (有磁性的) and shaped like stars. When sunlight hits them, they produce chemical reactions that push them through water in a specific direction. When they find a piece of plastic, they stick to it and start to break it down. When the light goes out, they let go and are free to be used again.

“This work is great,” says Douglas Blackiston at Tufts University in Medford, Mass. He’s a biologist who did not work on the project but knows about such devices. He’s been designing robots out of living cells, including some that might help with pollution cleanup. Speaking of the new one, he mentions that, “These robots can eat plastic. They chew it up. Or they can recover it and be collected with a magnet. Scientists love robots with all these capabilities. ”

Chemist Martin Pumera at the Czech University of Chemistry and Technology in Prague led the project. He studies ways to build microrobots. About a decade ago, he says, scientists began developing tiny bots that could move themselves in water. Then, they had to find them a mission and thought “Let’s make them do something useful.” Since then, Pumera has focused on the problem posed by microplastics, which are everywhere—from the bottom of the ocean to air blowing onto ice atop mountains. They’ve turned up in drinking water, both bottled and tap water, and some studies estimate that trillions of pieces of plastic end up in the world’s waters. The plastic has many sources, from drinking straws and shopping bags to laundry and cleaning wipes. Plastic doesn’t easily degrade or fall apart, and that’s always been one of its appeals.

Pumera says his final goal is to make cheap and environmentally friendly robots that can be used anywhere in the world.

3 . Peacocks (孔雀) have been troublesome birds of the Palos Verdes Peninsula and the San Gabriel Valley for decades, destroying gardens, blocking traffic, leaving droppings on roofs and making noises. Much to neighbors’ annoyance, some people leave out seeds and bread for the bright-colored feathered birds.

On Tuesday, the Los Angeles County Board of Supervisors decided that feeding peacocks is a misdemeanor, a slight crime, in unincorporated areas and the 44 cities that contract (签合同) with the county animal control department. Misdemeanors are punishable by up to six months in prison, a fine of up to $1, 000 or both. Contract cities can quit this rule, while unincorporated areas cannot, said Marcia Mayeda, director of the LA County Department of Animal Care and Control.

Some cities, including Pasadena and Arcadia, already ban feeding peacocks. Among the peacock-rich communities covered by the rule are Rancho Palos Verdes and Rolling Hills, as well as Chapman Woods near Pasadena.

“If a city said, We don’t want to adopt this. We have a different way of handling peacocks, we would agree to that, ” Mayeda said. According to him, animal control officers generally leave peacocks alone, as“they’re a difficult bird to catch”. Instead, the county will contract with wildlife expert Mike Maxcy, who worked at the Los Angeles Zoo for 33 years and has resettled peafowl, a kind of peacock, in large farms since 1999.

Peafowl are smart, eating practically anything and everything, Maxcy said. In adulthood, they don’t face many killers, other than humans. Feeding the birds, which are not native to Southern California, causes the population to increase, as they lay more eggs when resources are abundant. LA County’s peacock population has been increased by years of human feeding.

Thus, the problems are posed by their fans. “They’re all in very nice neighborhoods with very nice homes and tall, old pine trees (where they sleep), and dare I say, animal fans that love to feed them, ”Maxcy said.

4 . Many are familiar with the potentially deadly danger caused by lightning, which is blamed for an average of 43 deaths in the United States each year, based on data from 1989 to 2018. However, the researchers recently uncovered a surprising and beneficial impact of lighting.

Published at the end of April in Science, the new study found that lightning may play a bigger role in global climate change than what was previously known by the   scientific community, “Lightning increases the atmosphere's ability to clean itself,” the researchers wrote in the study.

The study, which included efforts from nine atmospheric experts across a dozen universities and meteorological agencies, was based on an airborne research flight conducted by a NASADC-8 storm-chasing plane in 2012. The plane used to examine the top part of the top part of thunderstorm clouds, which are known as anvils (砧状云).

According to Dr.William Brune, a professor of meteorology and atmospheric sciences at Pennsylvania State University and co-author of the study, researchers initially thought there was a problem with the equipment on the plane, which was being used to measure the hydroxyl radicals（羟基自由基）in the atmosphere. But soon they realized the sharp increase they observed came along with lightning flashes.

Hydroxyl radicals, described as a “chemical cleaner” by Science Direct, are important chemical compounds (化合物) found in the atmosphere due to the reactive nature with other organic molecules (有机分子).

Researchers previously understood that lightning could help to clean the atmosphere, but there was no evidence that it could produce compounds like these radicals. As a result, the study estimates that somewhere between 2% and 16% of the cleaning that happens naturally in the Earth's atmosphere, is done by lightning.

Why is this significant? The existence of the hydroxyl radicals helps to reduce chemicals like carbon dioxide and methane in the atmosphere. These chemicals, known for greenhouse gases, have been proven to contribute to rising temperatures associated with climate change.

6 . Findings of an international team of researchers from Japan and China suggest that geese might have been the first poultry species to have been domesticated (驯养) by humans—as far back as 7,000 years ago.

Scientists have long held different opinions on the history of the domestication of birds, with a belief that it was chickens that were the first to be domesticated. In 2014, Chinese researchers reported ancient DNA taken from the earliest archaeological chicken bone discovery in China, suggesting chickens were domesticated in northern China as early as 10,000 years ago.

But the researchers behind the latest findings say that the 2014 study lacks firm evidence. In the new study, the team unearthed the archaeological site of Tianluoshan, a 7,000-year-old rice cultivation village in the lower Yangtze River valley in what is today known as East China’s Zhejiang province. They found a total of 232 goose bones at the site. The inhabitants of the village were hunter-gatherers.

The researchers used multiple approaches to study the bones, and found evidence of domestication.

Four bones were from goslings (幼鹅) ranging from eight to 16 weeks old, suggesting they hatched near the site. Geese were domesticated from wild geese. These migratory birds fly to northern Siberia to breed (繁殖) after the spring and then fly south for the winter, according to researchers from the Zhejiang Provincial Institute of Cultural Relics and Archaeology. They said the goslings were too young to have flown in from elsewhere. At the time, Tianluoshan did not have the conditions to be a natural breeding place for wild geese, so it follows that the goslings were born after domestication.

The researchers also analyzed the chemical makeup of adult goose bones, which contained evidence of the water they drank. Their analysis indicated that the adult geese also seemed to have been locally bred, for they were all roughly the same size. Carbon dating also showed that the bones belonged to geese that lived about 7,000 years ago.

Researchers say ancient DNA analysis is required in further studies to investigate which species were bred to become local geese populations.

10 . The national parks of Russia are attracting many tourists. To make the selection of the popular parks easy for you, we prepared a few national parks worth visiting.

◎ Elk Island, Moscow

Elk (麋鹿) Island is the very first national park of Russia. It was established in the year 1983. The park is located to the north of the Capital City. If you are a true love of nature, then here you can enjoy riding a bicycle in the park. The entrance of this park is near the Belokamennaya station and no entry fee is there. If you are willing to visit the elks, then you need to take a bus directly from the metro station.

◎ Pleshcheyevo Lake, Yaroslavl

It is located on the golden rule tourist route, and here you will get the feeling of ancient Rus. Travelers here love the picturesque view of the Sunset. The ancient city Pereslavl-Zalessky is surrounded by this park. You can get a bus directly from the Moscow Central Station.

◎ Sochi National Park, Moscow

This park was also started in the year 1983. This park is situated 1000 miles south of Moscow. It is quite impressive to notice that since 2007, Caucasian leopards have been introduced again in this park. Waterfalls, caves, and canyons altogether make the atmosphere really enjoyable and you can also take pleasure swimming in the warm black sea.

◎ Land of the Leopard, Vladivostok

If you are desirous to watch leopards, then Vladivostok is definitely the best place to visit. This place is situated 5600 miles away from east Moscow and here you will be able to get a glimpse of the wild cats — leopards. This region is spread from the Amur Bay. There is one single tourist route to enter the park.