1 . Artificial Intelligence Develops an Ear for Birdsong
We can learn a lot from nature if we listen to it more — and scientists around the world are trying to do just that. From mountain peaks to ocean depths, biologists are planting audio recorders to eavesdrop (窃听) on the whistles and songs of whales, elephants, bats and especially birds. This summer, for example, over 2,000 electronic ears will record the sound scape of California’s Sierra Nevada mountain range.
“Audio data is a real treasure because it contains vast amounts of information,” says ecologist Connor Wood, a Cornell University postdoctoral researcher, who is leading the Sierra Nevada project. “We just need to think creatively about how to share and access that information.”
Stefan Kahl, a machine-learning expert at Cornell’s Center for Conservation Bioacoustics and Chemnitz University of Technology in Germany, built BirdNET, one of the most popular avian-sound-recognition systems used today. Wood’s team will rely on BirdNET to analyze the Sierra Nevada recordings.
A.A wealth of such data already exists for common birds. |
B.They altogether will generate nearly a million hours of audio. |
C.These machine-learning AI systems still have room for improvement. |
D.Such recordings can create valuable snapshots (简介) of animal communities. |
E.This is a tricky problem because it takes humans a long time to decode recordings. |
F.Such systems start by analyzing hundreds of recorded bird calls, each “labeled” with its corresponding species. |
Most of us would like to have a bright, “white” smile—filled with teeth that would make a Hollywood actor proud. Studies show that up to 52 percent of people are dissatisfied with the color of their teeth.
It is hardly surprising, then, that we tend to think that white teeth are not only attractive but also healthy. However, new studies have revealed that pearly teeth don’t always mean great oral health.
There is even one type of stain that some researchers believe might protect against tooth decay. This is the “black stain” which you sometimes see along teeth at the edges of the gum line(牙龈线). It can look like a series of dark dots. While the cause of the black stain has been in debate for more than a century, some studies have found that children with the stain are less likely to have tooth decay. It’s thought that some microbes in the stain might be somehow protective.
So what if you still want pearl-white teeth, regardless of what they say about your health? There is a wide range of products you can use. Some kinds of toothpaste promise a whitening effect. Most of them contain substances that rub stains off your teeth. Others add some blueish substances to your yellowish teeth, resulting in a bright white color.
Of course, unless you continue using the product or receiving the whitening treatment, the whiteness will only last for as long as you avoid the foods and drinks that cause the stains in the first place. But now you know that even without that Hollywood white smile, it doesn’t mean you don’t have healthy teeth.
A.Many of the experiments on tooth color have been conducted in laboratory test tubes, rather than in the mouths of living people. |
B.In countries such as the United States, tooth whitening is one of the most commonly requested dental treatments. |
C.The color of our teeth is influenced by a number of factors. |
D.It is no surprise that the red wine leaves the strongest stains. |
E. There are also professional whitening treatments, but whitening can cause temporary sensitivity in some people’s teeth or gums. |
F. Of course, in some cases, discoloration can indicate decay or other diseases, so it is worth getting stains checked out by a dentist. |