A new computer program has an ear for dolphin chatter.

The algorithm uncovered six previously unknown types of dolphin echolocation clicks in underwater recordings from the Gulf of Mexico, researchers report online December 7 in PLOS Computational Biology. Identifying which species produce the newly discovered click varieties could help scientists better keep tabs on wild dolphin populations and movements.

Dolphin tracking is traditionally done with boats or planes, but that’s expensive, says study coauthor Kaitlin Frasier, an oceanographer at the Scripps Institution of Oceanography in La Jolla, Calif. A cheaper alternative is to sift through seafloor recordings — which pick up the echolocation clicks that dolphins make to navigate, find food and socialize. By comparing different click types to recordings at the surface — where researchers can see which animals are making the noise — scientists can learn what different species sound like, and use those clicks to map the animals’ movements deep underwater.
But even experts have trouble sorting recorded clicks, because the distinguishing features of these signals are so subtle. “When you have analysts manually going through a dataset, then there’s a lot of bias introduced just from the human perception,” says Simone Baumann-Pickering, a biologist at the Scripps Institution of Oceanography not involved in the work. “Person A may see things differently than person B.” So far, scientists have only determined the distinct sounds of a few species.
To sort clicks faster and more precisely, Frasier and her colleagues outsourced the job to a computer. They fed an algorithm 52 million clicks recorded over two years by near-seafloor sound sensors across the Gulf of Mexico. The algorithm grouped echolocation clicks based on similarities in speed and pitch — the same criteria human experts use to classify clicks. “We don’t tell it how many click types to find,” Frasier says. “We just kind of say, ‘What’s in here?’”
The algorithm picked out seven major kinds of clicks, which the researchers think are made by different dolphin species. Frasier’s team recognized one class as being made by a species called Risso’s dolphin. The scientists suspect that another group of clicks, most common in recordings near the Green Canyon south of Louisiana, was produced by short-finned pilot whales that frequent this region. Another type resembles sounds from the eastern Pacific Ocean that a dolphin called the false killer whale makes.
To confirm the identifications, the researchers now need to compare their computer-generated categories against surface observations of these dolphins, Frasier says.

The algorithm’s click classes may not match up with dolphin species one-to-one, says Baumann-Pickering. If that were the case, “we would expect to see a heck of a lot more categories, really, based on the number of species that ought to be in that area,” she says. That absence suggests that some closely related species produce highly similar clicks the algorithm didn’t tease apart.

Still, “it would be great to be able to confidently assign certain species to each of the different click types, even if more than one species is assigned to a single click type,” says Lynne Hodge, a marine biologist at Duke University who wasn’t involved in the work. More precisely monitoring dolphins with seafloor recordings could provide new insight into how these animals respond to environmental problems such as oil spills and the long-term effects of climate change.

During the world’s first telephone call in 1876, Alexander Graham Bell summoned his assistant from the other room, stating simply, “Mr. Watson, come here. I want to see you.” In 2017, scientists testing another newfangled type of communication were a bit more eloquent. “It is such a privilege and thrill to witness this historical moment with you all,” said Chunli Bai, president of the Chinese Academy of Sciences in Beijing, during the first intercontinental quantum-secured video call.

The more recent call, between researchers in Austria and China, capped a series of milestones reported in 2017 and made possible by the first quantum communications satellite, Micius, named after an ancient Chinese philosopher (SN: 10/28/17, p. 14).
Created by Chinese researchers and launched in 2016, the satellite is fueling scientists’ dreams of a future safe from hacking of sensitive communiqués. One day, impenetrable quantum cryptography could protect correspondences. A secret string of numbers known as a quantum key could encrypt a credit card number sent over the internet, or encode the data transmitted in a video call, for example. That quantum key would be derived by measuring the properties of quantum particles beamed down from such a satellite. Quantum math proves that any snoops trying to intercept the key would give themselves away.

“Quantum cryptography is a fundamentally new way to give us unconditional security ensured by the laws of quantum physics,” says Chao-Yang Lu, a physicist at the University of Science and Technology of China in Hefei, and a member of the team that developed the satellite.

But until this year, there’s been a sticking point in the technology’s development: Long-distance communication is extremely challenging, Lu says. That’s because quantum particles are delicate beings, easily jostled out of their fragile quantum states. In a typical quantum cryptography scheme, particles of light called photons are sent through the air, where the particles may be absorbed or their properties muddled. The longer the journey, the fewer photons make it through intact, eventually preventing accurate transmissions of quantum keys. So quantum cryptography was possible only across short distances, between nearby cities but not far-flung ones.

With Micius, however, scientists smashed that distance barrier. Long-distance quantum communication became possible because traveling through space, with no atmosphere to stand in the way, is much easier on particles.
In the spacecraft’s first record-breaking accomplishment, reported June 16 in Science, the satellite used onboard lasers to beam down pairs of entangled particles, which have eerily linked properties, to two cities in China, where the particles were captured by telescopes (SN: 8/5/17, p. 14). The quantum link remained intact over a separation of 1,200 kilometers between the two cities — about 10 times farther than ever before. The feat revealed that the strange laws of quantum mechanics, despite their small-scale foundations, still apply over incredibly large distances.

Next, scientists tackled quantum teleportation, a process that transmits the properties of one particle to another particle (SN Online: 7/7/17). Micius teleported photons’ quantum properties 1,400 kilometers from the ground to space — farther than ever before, scientists reported September 7 in Nature. Despite its sci-fi name, teleportation won’t be able to beam Captain Kirk up to the Enterprise. Instead, it might be useful for linking up future quantum computers, making the machines more powerful.

The final piece in Micius’ triumvirate of tricks is quantum key distribution — the technology that made the quantum-encrypted video chat possible. Scientists sent strings of photons from space down to Earth, using a method designed to reveal eavesdroppers, the team reported in the same issue of Nature. By performing this process with a ground station near Vienna, and again with one near Beijing, scientists were able to create keys to secure their quantum teleconference. In a paper published in the Nov. 17 Physical Review Letters, the researchers performed another type of quantum key distribution, using entangled particles to exchange keys between the ground and the satellite.

The satellite is “a major development,” says quantum physicist Thomas Jennewein of the University of Waterloo in Canada, who is not involved with Micius. Although quantum communication was already feasible in carefully controlled laboratory environments, the Chinese researchers had to upgrade the technology to function in space. Sensitive instruments were designed to survive fluctuating temperatures and vibrations on the satellite. Meanwhile, the scientists had to scale down their apparatus so it would fit on a satellite. “This has been a grand technical challenge,” Jennewein says.

Eventually, the Chinese team is planning to launch about 10 additional satellites, which would fly in formation to allow for coverage across more areas of the globe.

A type of spiraling wave has been busted for disorderly conduct.

Spiral waves are waves that ripple outward in a swirl. Now scientists from Germany and the United States have created a new type of spiral wave in the lab. The unusual whorl has a jumbled, disordered center rather than an orderly swirl, making it the first “spiral wave chimera,” the researchers report online December 4 in Nature Physics.

Waves, which exhibit a variety of shapes, are common in nature. For example, they can be found in cells that undergo cyclical patterns, such as heart cells rhythmically contracting to produce heartbeats or nerve cells firing in the brain. In a normal heart, electrical signals propagate from one end to another, triggering waves of contractions in heart cells. But sometimes the wave can spiral out of control, creating swirls that can lead to a racing or irregular heartbeat. Such spiral waves emanate in an orderly fashion from a central point, reminiscent of the red and white swirls on a peppermint candy. But the newly observed spiral wave chimera is messy in the middle.
Harnessing an oscillating chemical process known as the Belousov–Zhabotinsky reaction, the researchers created the wave using an array of small beads, each containing a catalyst for the reaction. When placed in a chemical solution, the beads acted as individual pulsating oscillators — analogous to heart cells — in which the reaction took place.

The researchers monitored the brightness of each bead as it alternated between a fluorescent state that emits red light and a dim state. Because the reaction is light sensitive, illuminating individual beads allowed the researchers to induce nearby beads to sync up. Thanks to that syncing, a spiral wave took shape. But, unlike any seen before, it had a muddled center.
The wave is a new kind of “chimera,” a grouping of oscillators in which some sync up, but others march to their own drummer, despite being essentially identical to their neighbors. Although researchers have previously created other kinds of chimeras in the lab, “it’s a step further to show that you can have this in even more complex setups” such as spiral wave chimeras, says Erik Martens of the Technical University of Denmark in Kongens Lyngby, who was not involved with the research.

While spiral wave chimeras had been predicted theoretically, there were some surprises to the real-world curlicues. Single spirals, for example, sometimes broke up into several independent swirls, each with disordered centers. “That was quite unexpected,” says chemist Kenneth Showalter of West Virginia University in Morgantown, a coauthor of the study.

It’s still not known whether the chimera form of spiral waves can appear in biological systems like the heart or the brain — but the new whorl is one to watch out for.

Robots are on their way to passing gym class.

The design of a new life-size bot named Kengoro closely resembles the anatomy of a teenage boy in body proportion, skeletal and muscular structure, and joint flexibility, researchers report online December 20 in Science Robotics. Compared with previous humanoid robots with more rigid, bulky bodies, Kengoro’s anatomically inspired design gives the bot a wide range of motion to perform humanlike, full-body exercises.
Constructed by Masayuki Inaba, an engineer at the University of Tokyo, and colleagues, Kengoro has a multi-jointed spine that allows the robot to curl into a sit-up or do back extensions. The bot’s arms are limber enough to execute various stretches or swing a badminton racket. And its artificial muscles are strong enough that Kengoro can stand on tiptoe or do push-ups. Batteries in each leg power Kengoro through about 20 minutes of exercise at a time, and water seeping from inside Kengoro’s metal skeleton like sweat keeps the motors of the artificial muscles cool while the bot works out.

Such a nimble robot that so closely imitates human movement and anatomy is “very unique,” says Luis Sentis, an engineer at the University of Texas at Austin not involved in the work. Building more humanlike robots could lead to the development of more sophisticated prosthetics or more realistic crash-test dummies that make humanlike reflexive movements during an accident.