Anyone who’s lived through middle school knows those years can be particularly challenging. Teaching students bike riding skills as part of physical education classes may help improve their mental health, a new study found. The study comes at a time when research shows that youths across the U. S. are starting to experience all sorts of social pressures, anxiety, stress from school, stress from home. So it’s a really important time to provide additional chances to explore not only physical activity, but also the freedom and relief that can come with going out for a bike ride during the day.

The study involved more than 1,200 middle schoolers, ages 11 to 14. They participated in a cycling class for at least three days a week, for a minimum of 6 weeks. They learned cycling safety and maneuvering (操作) skills outdoors while raising their heart rate and just having fun. They completed standardized screening questionnaires before and after the program designed to measure their well-being. It showed that some of the participants’ mental health was improved. “Cycling engages all of these other parts of brain function,” says Reiss, a child and adolescent neuropsychiatrist. “You’re looking at your hearing, you’re balancing, you’re navigating and turning. But often, you’re doing it with someone else, so there’s the positive effect of company or group activity. And that’s the point!”

Of course, while exercise has powerful mental health benefits, it’s not a panacea. For example, previous research has shown that adolescent girls are at higher risk of mental health problems like depression and anxiety than boys. The current study found that, while middle school girls reported increased well-being after participating in the cycling program, that increase “may just reach the kind of baseline level for male students,” says Esther Walker, the senior research program manager.

It’s the harvest (收获) season in many parts of the world, but on the farm of Harper Adams University in the U.K., it is robots- not humans that are doing all the heavy lifting.

At Hands Free Hectare, an experimental farm run by a group of researchers, about 5 tons of spring barley (大麦) have been harvested from the world’s first robotically tended farm. Everything from start to finish, including seeding, fertilizing (施肥), collecting patterns and harvesting, has been done by unmanned equipment, according to the researchers. The team behind the project thinks that robotic technology could improve production in agriculture, which would be necessary if the world’s growing population is to be fed in coming years.

The researchers dealt with this problem by using agriculture machines available on the market and software that is used to guide autopilot drones(无人机). The rescarchers bought several small-size agricultural machines, including a tractor and a combine (联合收割机), a machine for harvesting crops. “The first stage was to make them radio controlled,” said Jonathan Gill, a head researcher, who led the project. “This was our first step towards the driverless goal. From that point. we moved on to preprogram all the actions that needed to be performed into the driverless system.” To monitor the field and take patterns of the plants, the researchers developed special grippers (夹持器) attached to the autopilot drones. As the drones fly above the field, the grippers can cut off some patterns and take them to the researchers.

The scientists said the robotic technology could enable future farmers to more exactly use fertilizers and farm chemicals, but also lead to improvements in soil quality. Currently, many farmers rely on very large and heavy machines. They cover large areas of ground quickly, but it comes with mistakes. In the future, farmers would make use of smaller robotic tractors and harvesters.

The Harper Adams University team plans to use the robotically harvested spring barley to make limited “hands-free” beer that will be offered to the projects supporters as a symbol of thanks.

The people who happen to be in a city center at any given moment may seem like a random collection of individuals. But new research featuring a simple mathematical law shows that urban travel patterns worldwide are, in fact, predictable despite location.

Researchers discovered what is known as an inverse square relation (平方反比关系) between the number of people in a given urban location and the distance they traveled to get there, as well as how frequently they made the trip. It may seem intuitive (直觉的) that people visit nearby locations frequently and distant ones less so, but the newly discovered relation accurately predicts, for instance, that the number of people coming from two kilometers away five times per week will be the same as the number coming from five kilometers twice a week.

The researchers analyzed data from about eight million people between 2006 and 2013 in six urban locations. This study focused on locations and examined how many people were visiting, from how far and how frequently. The researchers found that all the unique choices people make—from dropping kids at school to shopping-obey this inverse square law.

One explanation for this strong statistical patter is that traveling requires time and energy, and people have limited resources for it. At the core is the effort that people are willing to invest collectively to travel to certain locations, trying to optimize their days.

Understanding these patterns is important not only for planning the placement of new shopping centers or public transportation but also for modeling disease transmission within cities, says Kathleen Stewart, a geographer and mobility researcher.

Many researchers estimate travel with “gravity models”, which assume that movement between cities is proportional (成比例的) to their population sizes. But these models do not account for travel patters within cites—information that is particularly critical in dealing with disease transmission Epidemiologist (流行病学家) Sam Scarpino says models based on this new finding might better track that flow.

“Those organizational patterns have really profound (深远的) implications on how COVID will spread,” Scarpino says. In a smaller rural location, where many people regularly go to the same grocery store, the entire town will experience sharp peaks of infections as the virus sweeps through the community. But in a bigger city, the spread takes longer he explains, because mini epidemics can occur in each neighborhood somewhat separately.