【推荐1】We've known for years that plants can see,hear,smell and communicate with chemicals.Now, reported New Scientist,they have been recorded making sounds when stressed.

In a yet-to-be-published study, Itzhak Khait and his team at Tel Aviv University, in Israel, found that tomato and tobacco plants can make ultrasonic(超声的)noises. The plants "cry out" due to lack of water,or when they are cut. It's just too high-pitched(音调高的）for humans to hear.

Microphones placed 10 centimeters away from the plants picked up sounds in the ultrasonic range of 20 to 100 kilohertz(干赫兹)。Human hearing usually ranges from 20 hertz to 20 kilohertz."These findings can change the way we think about the plant kingdom,”they wrote.

On average,"thirsty"tomato plants made 35 sounds an hour,while tobacco plants made 11. When they were cut,tomato plants made an average of 25 sounds in the following hour,and tobacco plants 15.Unstressed plants produced less than one sound per hour,on average.

Perhaps most interestingly,different types of stress led to different sounds.The researchers trained a machine-learning model to separate the plants' sounds from those of the wind,rain and other noises of the greenhouse.In most cases,it correctly recognized whether the stress was caused by dryness or a cut.Water-hungry tobacco appears to make louder sounds than cut tobacco,for example.Although Khait and his colleagues only looked at tomato and tobacco plants,they think other plants also make sounds when stressed.

If farmers could hear these sounds,said the team,they could give water to the plants that need   it most.As climate change causes more droughts,they said this would be important information for farmers. "The sounds that drought-stressed plants make could be used in precision(精准) agriculture, "said Anne Visscher at the Royal Botanic Gardens,Kew,in the UK.

Khait's report also suggests that insects can hear the sounds up to 5 meters away and respond. For example,a moth(蛾子）may decide not to lay eggs on a water-stressed plant.Edward Farmer. at the University of Lausanne,Switzerland,is doubtful.He said that the idea of moths listening to plants is"a little too speculative”。

If plants are screaming(尖叫）for fear of their survival,maybe we should be glad we can't hear them.

【推荐3】Ever wondered if dogs can learn new words? Yes, say researchers as they have found that talented dogs may have the ability to learn new words after hearing them only four times.

While previous evidence（以前的证据）seems to show that most dogs do not learn words, unless very well trained, a few individuals（个体） have shown some extraordinary（不一般的） abilities, according to a study published in the journal Scientific Reports.

“We wanted to know under which conditions the talented dogs may learn new words,” said researcher xuekw Claudia Fugazza from the Eötvös Loránd University in Hungary（匈牙利）. For the study, the team involved（包含）two gifted dogs, Whisky and Vicky Nina. The team exposed（暴露）the dogs to the new words in two different conditions.

In the exclusion-based（基于排除的）task, presented with seven known toys and one new toy, the dogs were able to select（选择）the new toy when presented with a new name. Researchers say this proves that dogs can choose by exclusion（排除）when faced with a new word, they selected the only toy which did not have a known name.

However, this was not the way they would learn the name of the toy. In fact, when they were presented with one more equally（同等地）new name to test their ability to recognize the toy by its name, the dogs got totally confused and failed.

The other condition, the social one, where the dogs played with their owners who pronounced the name of the toy while playing with the dog, proved to be the successful way to learn the name of the toy, even after hearing it only 4 times. “The rapid learning that we observed seems to equal children’s ability to learn many new words at a fast velocity around the age of 18 months,” Fugazza says. “But we do not know whether the learning mechanisms（机制）behind this learning are the same for humans and dogs. ”

To test whether most dogs would learn words this way, 20 other dogs were tested in the same condition, but none of them showed any evidence of learning the toy names, confirming（确认）that the ability to learn words rapidly in the absence（缺乏）of formal training is very rare（少） and is only present in a few talented dogs.

【推荐2】Over a million children have developed some form of intellectual （智力） disability over the past two decades after being exposed to chemicals including flame retardants, pesticides, lead, and mercury, a study has revealed.

The study focused on the four chemicals, which can be crossed from a mother to her unborn baby through the placenta（胎盘）and cause neurodevelopmental damage. The researchers looked at data from past studies, including blood samples taken from women of childbearing age and 5-year-olds.

Over the period, flame retardants, resulted in 738,860 cases of intellectual disability and an estimated 162 million lost IQ （智商）points, followed by lead at 330,684 cases, pesticides at 111,830, and mercury at 8,860. In recent years, pesticides and flame retardants have overtaken lead and mercury as the chemicals responsible for the biggest loss of IQ among children.

The researchers believe this is due to regulations cutting down the use of these chemicals. For instance, lead has been banned from gasoline, paint and drinking water systems in the U.S. and plants are not allowed to pump out mercury.

The researchers acknowledged limitations to their study, including that the exposure-response relationships might not relate to all populations. Positively, they found a huge drop in the estimated loss of IQ points among children.

Lead researcher Abigail Gaylord, commented: "Our findings suggest that our efforts to reduce exposure to heavy metals are paying off, but that harmful exposures in general continue to represent a terrible risk to people's physical, mental, and economic health. "Unfortunately, the minimal policies in place to remove pesticides and flame retardants are clearly not enough," she said.

She also added. Frequently opening windows to let persistent chemicals found in furniture   electronics, and carpeting escape, and eating certified organic produce can educe exposure to these harmful things"

【推荐3】People with bigger brains tend to score higher on standardized tests of intelligence, according to new study findings.

Interest in the relationship between brain size and intelligence grew in the1830s, when German anatomist(解剖学家) Frederich Tiedmann wrote that he believed there was "an unquestionable connection between the size of the brain and the mental energy displayed by the individual man". Since that statement, scientists have conducted numerous studies to determine if Tiedmann's assertion was correct. Most studies have looked into the link between head size and intelligence. More recently, however, researchers have published additional studies on brain size and intelligence, measured using MRI scan(核磁共振成像扫描).

For his study, McDaniel analyzed more than 20 studies that looked into the relationship between brain size and intelligence in a total of 1,530 people. The studies showed that on the average, people with larger brain volume tended to be more intelligent. The relationship between brain volume and intelligence was stronger in women than men, and in adults than in children. McDaniel notes in the journal Intelligence.

McDaniel is not sure why the relationship was stronger for adults and women. "Other research has shown that women, on the average, tend to have smaller brains than men, but score just as well—if not higher—in tests of intelligence," he said.

McDaniel insisted that the relationship between brain size and intelligence is not a "perfect" one. "One can certainly find lots of examples of smaller-sized people who are highly intelligent," he said, "But, on the average, the relationship holds."

【推荐3】Hey Jude is the Beatles song most likely to be bellowed by a choir of thousands. Any good song needs to be singable, but Hey Jude goes further: It's yellable and flexible. Into the gap after “Nahh, na, na, nahh-na-na, nahh”, you can slot(把....放入) almost any pair of syllables.

It's a crowd-pleaser. This month, Hey Jude was the No.1 Beatles song on Apple Music; On Spotify, it was No.4. So, of all the countless classics the Beatles recorded, Hey Jude is one of the four that younger music lovers most want to hear. What is its secret?

Written by McCartney, Hey Jude bears his signature touch: empathy(同情) set to elegance. As McCartney melodies go，it's direct, running straight into its title, just like She Loves You. The tune and the idea of the lyrics came to McCartney in 1968, when he was driving from London to Surrey to see Julian Lennon after John had left him for Yoko Ono, a Japanese singer and songwriter. Hey Jude began as Hey Jules, like an arm around the shoulder of a five-year-old, so the compassion was there all along.

By then, Lennon and McCartney were writing separately, but still acting as each other's sounding board. After working on Hey Jude some more, McCartney invited Lennon to his house and played it to him. One line, “The movement you need is on your shoulder”, was there as a placeholder(占位符). McCartney thought “it's not that good”，but Lennon believed“that's the best line in it”.

These exchange，recounted by McCartney in 1994, had two consequences, beyond preserving the line.“You love it twice as much", he said; it would forever remind him of Lennon: It's an emotional point in the song.