【推荐1】A dog’s behavior is far more influenced by environment and upbringing, according to a new study published in the journal Science.

Lead author Kathleen Morrill, a Ph. D. candidate at the University of Massachusetts Medical School, and her numerous co-researchers surveyed owners of 18,385 dogs and examined 2,155 dogs’ DNA as part of the citizen science project Darwin’s Ark.

For the project, participants were given a battery of surveys to fill out about their dogs. They then received a DNA kit to collect their dogs’ saliva (唾液) and send it back to the lab for DNA testing. The information was stored in a large database that was freely shared with researchers around the world. In return, curious dog owners were sent a DNA and breed (品种) profile of their dogs.

With the data provided to them by citizen scientists, Morrill and her team presented a number of interesting findings, but the biggest was this: Breeds offer little predictive value for individuals, explaining just 9% of variation in behavior.

The researchers broke down dog behavior into eight categories: comfort level around humans, case of stimulation or excitement, affinity (喜爱) toward toys, biddability (also known as response to human training), how easily the dog is affected by a frightening stimulus, comfort level around other dogs, engagement with the environment, and desire to be close to humans. Of these behavioral characteristics, biddability and toy affinity were most linked with breeds, but the associations were slight.

The study’s findings call into question laws that target specific, supposedly “dangerous”, breeds. More than 900 cities in the U.S. currently have some breed-specific laws.

“We now have demonstrated that breed-specific laws are ineffective at protecting the public or reducing dog attacks,” Elinor Karlsson, a senior author of the study, said. “Any dog has the potential to be dangerous, regardless of its size or breed background. Because of this, dogs should not be declared dangerous based on their appearance. Instead, they should be assessed as individuals based on their behavior.”

【推荐3】Listening to birds sing or watching them fly is more than just entertaining. Being around birds offers benefits for emotional well-being, a new study finds.

Researchers used a phone app to collect information on how this specific nature exposure could be good for mental wellness.

“Most previous studies have looked at the benefits of nature as a whole,” says lead author Ryan Hammoud, a research assistant at King’s College London. “We chose to focus on birdlife to try and understand which specific characteristics of nature benefit mental health. None of the previous studies had investigated this in real-time and real-world contexts.

For their experiments, researchers used the Urban Mind app to follow 1,292 people who completed nearly 27,000 assessments. Participants were from the United Kingdom, the European Union, and the United States. Three times each day, the app asked users whether they could hear or see birds. They were asked to answer follow-up questions on their mental state at the time, so researchers could see if there was a connection and how long it lasted.

Mental well-being was measured with questions about whether they were feeling confident, relaxed, happy, for example, or more negative feelings such as whether they felt anxious, stressed, or lonely.

The study collected data on people who have mental health conditions and those without. They discovered that bird activity is linked to improvements in emotional health in those who don’t have mental health concerns, as well as those who have been diagnosed with depression. They discovered that the effects were still observed in the following assessment which was up to eight hours later.

This exciting research shows just how much the sight and the sound of birdsong lift the spirits. It captures evidence that our senses are stimulated by birdsong, which is a precious part of nature that should be experienced.

【推荐3】In our daily life, it has never been easier to understand time: The National Institute of Standards and Technology (NIST) broadcasts the time to points across the country and then it’s fed through computer networks and cellphone towers to our personal devices. The time from NIST keeps society organized and increases economic productivity.

“Growing up, a lot of us are fed with this concept of absolute time,” says Chanda Prescod Weinstein, a theoretical physicist at the University of New Hampshire. “But the time we’re experiencing is a social construct. Real time is something quite different. In some of the corners of the Universe, space and time can stretch and slow-and sometimes even break down completely.”

For many people, his idea of time is unbelievable. But true time is actually much more flexible than most people realize. According to Einstein’s general theory of relativity, space and time are tied together, and space-time can bend and curve (弯曲). As time stretches, it slows.

The best-known force that stretches time is gravity. The more gravity somebody experiences, the slower time passes for them when compared to someone in a lower gravitational field. In places where gravity is very strong, time as we understand can break down completely. At the edge of black holes, for example, the gargantuan gravitational pull slows time dramatically.

“Upon crossing the black hole’s point of no return, known as its event-horizon, you end up in a region where time breaks down entirely, ”Weinstein says. “At that point time has no real meaning. There is no direction. There is no future. ”

The scientists at NIST are well aware of all the problems with time. “Just as humans keep improving their maps, we must improve our clocks. Better clocks can make GPS more accurate, computer networks faster, and much, much more,” says John Kitching, one of the NIST scientists. “But it’s pretty hard to define time in a satisfactory way.”

Kitching agrees with Weinstein that time as we experience it is a technology rather than a fundamental part of the Universe. “From a physics sense, it doesn’t have that much value,” he concludes.