Can a small group of drones（无人机）guarantee the safety and reliability of railways and, at the same time, help railway operators save billions of euros each year? That is the very likely future of applying today's "eyes in the sky" technology to making sure that the millions of kilometres of rail tracks and infrastructure（基础设施）worldwide are safe for trains on a 24/7 basis.

Drones are already being used to examine high-tension electrical lines. They could do precisely the same thing to inspect railway lines and other vital aspects of rail infrastructure such as the correct position of railway tracks and switching points. The more regularly they can be inspected, the more railway safety, reliability and on-time performance will be improved. Costs would be cut and operations would be more efficient（高效）across the board.

That includes huge savings in maintenance costs and better protection of railway personnel safety. It is calculated that European railways alone spend approximately 20 billion euros a year on maintenance, including sending maintenance staff, often at night, to inspect and repair the rail infrastructure. That can be dangerous work that could be avoided with drones assisting the crews' efforts.

By using the latest technologies, drones could also start providing higher-value services for railways, detecting faults in the rail or switches, before they can cause any safety problems. To perform these tasks, drones for rail don't need to be flying overhead. Engineers are now working on a new concept: the rail drones of the future. They will be moving on the track ahead of the train, and programmed to run autonomously. Very small drones with advanced sensors and AI and travelling ahead of the train could guide it like a co-pilot. With their ability to see ahead, they could signal any problem, so that fast-moving trains would be able to react in time.

Human speech contains more than 2, 000 different sounds, from the common "m" and "a" to the rare clicks of some southern African languages. But why are certain sounds more common than others? A ground-breaking, five-year study shows that diet-related changes in human bite led to new speech sounds that are now found in half the world's languages.

More than 30 years ago, the scholar Charles Hockett noted that speech sounds called labiodentals, such as "f" and "v", were more common in the languages of societies that ate softer foods. Now a team of researchers led by Damián Blasi at the University of Zurich, Switzerland, has found how and why this trend arose.

They discovered that the upper and lower front teeth of ancient human adults were aligned (对齐), making it hard to produce labiodentals, which are formed by touching the lower lip to the upper teeth. Later, our jaws changed to an overbite structure(结构), making it easier to produce such sounds.

The team showed that this change in bite was connected with the development of agriculture in the Neolithic period. Food became easier to chew at this point. The jawbone didn't have to do as much work and so didn't grow to be so large.

Analyses of a language database also confirmed that there was a global change in the sound of world languages after the Neolithic age, with the use of "f" and "v" increasing remarkably during the last few thousand years. These sounds are still not found in the languages of many hunter-gatherer people today.

This research overturns the popular view that all human speech sounds were present when human beings evolved around 300, 000 years ago. "The set of speech sounds we use has not necessarily remained stable since the appearance of human beings, but rather the huge variety of speech sounds that we find today is the product of a complex interplay of things like biological change and cultural evolution," said Steven Moran, a member of the research team.

During an interview for one of my books, my interviewer said something I still think about often. Annoyed by the level of distraction(干扰)in his open office, he said, “That's why I have a membership at the coworking space across the street —so I can focus. "His comment struck me as strange. After all, coworking spaces also typically use an open office layout (布局). But I recently came across a study that shows why his approach works

The researchers examined various levels of noise on participants as they completed tests of creative thinking. They were randomly divided into four groups and exposed to various noise levels in the background, from total silence to 50 decibels(分贝),70 decibels, and 85 decibels. The differences between most of the groups were statistically insignificant; however,the participants in the 70 decibels group—those exposed to a level of noise similar to background chatter in a coffee shop-significantly outperformed the other groups. Since the effects were small, this may suggest that our creative thinking does not differ that much in response to total silence and 85 decibels of background noise.

But since the results at 70 decibels were significant, the study also suggests that the right level of background noise—not too loud and not total silence—may actually improve one's creative thinking ability. The right level of background noise may interrupt our normal patterns of thinking just enough to allow our imaginations to wander, without making it impossible to focus. This kind of "distracted focus" appears to be the best state for working on creative tasks.

So why do so many of us hate our open offices? The problem may be that, in our offices, we can't stop ourselves from getting drawn into others' conversations while we're trying to focus. Indeed, the researchers found that face-to-face interactions and conversations affect the creative process, and yet a coworking space or a coffee shop provides a certain level of noise while also providing freedom from interruptions.