Windows are hard. They are particularly hard in northern countries like Sweden, where during winter the days are short and the sun is very low in the sky. Window design in cold climate is a technical balancing act. You want it big to get the light, but you want it small to minimize the heat loss. But there is so much more that windows have to do for our social and emotional well-being.

A recent study published in Buildings and Cities looks at the many roles that windows play and the way people use them, exploring daylight, the visual connection to the outside and the role of windows in the home during the day and night. Windows do much more than just provide light and air: "Windows represent an enjoyment of the home and fulfil much more than physical needs. They must allow sufficient personal control over fresh and cool air, sound, sunlight, street lighting and privacy. "

The study authors, Kiran Maini Gerhardsson and Thorbjorn Laike, interviewed occupants living in multi-family dwellings. Windows turned out to be very important for occupant comfort, for visual connection to the outside. But they also had to be able to be screened for privacy; sometimes these conflicted. Sometimes the sill height was important. One occupant, Dmitry was going to add some frosted film to the bottom of his window. "I don't want to see the faces of others when I'm sitting down, but when I'm standing and see their faces, I can wave to them," he said.

Interviewees preferred daylight to artificial light for many reasons, including as a time indicator, and "because it varies, increases room brightness and improves mood". Our bodies need the change from red to blue and back to red.

The authors conclude windows serve many functions that go beyond just light and air and should be designed accordingly. "There is much more to such experiences than the satisfaction of physical needs. Perceiving a room to be enough daylight, adequately pleasant and spacious seems to be equally essential, and a view of the world outside brings information to inhabit-ants. However, windows also need to prevent people outside from peering in moderate bright sunlight during the day. "

D

As the capabilities of artificial intelligence (AI) keep growing, some companies are hiring "AI prompt (提示) engineers" to help them get the best out of the emerging technology. Are these jobs set to become a universal presence, or are they a passing fad (时尚)? Generative AI creates text or images in response to prompts entered by the user. This can be as simple as asking for something in plain English, similar to using a search engine. But there is a key to it: including the right references and keywords that can guide AI towards the desired outcome.

"By buying a pre-built prompt given by prompt engineers, you can ensure the AI model will generate what you want. The average price is $3.50, but some prompts can cost hundreds of dollars," says Ben Stokes, the founder of Prompt Base. Most of the prompt engineers on the site don't have a technical background. The engineers tend to come from a photography or graphic design background, and those working on prompts for generating text used to work in marketing or copy writing.

Aaron Sines at US recruitment firm Razoroo has been placing engineers into AI jobs for five years, but only came across the term "prompt engineer" earlier this year. Sines says that a lot of the companies approaching him looking for a "prompt engineer" are actually seeking a more rounded AI researcher with technical skills. He believes AI models could become better at extracting (提取) information from humans about what they want, making the idea of a specialized prompt engineer obsolete, but thinks there will always be a need for humans to oversee AI models during development and application.

Zhan Qin at Zhejiang University in China says complex prompts, and the prompt engineers who create them, are unlikely to disappear any time soon because AI models aren't like traditional algorithms (算法) that work on logic and can be entirely understood by humans. "Some prompts are short. But there are a lot of very, very long prompts. Even the generators of those prompts do not know the exact meanings behind those magical words," says Qin.

Scientists have been experimenting with playing sounds to plants since at least the 1960s, during which time they have been exposed to everything from Beethoven to Michael Jackson. Over the years, evidence that this sort of thing can have an effect has been growing. One paper, published in 2018, claimed that an Asian shrub known as the telegraph plant grew substantially larger leaves when exposed to 56 days of Buddhist music—but not if it was exposed to Western pop music or silence. Another, published last year, found that marigolds and sage plants exposed to the noise of traffic from a busy motorway suffered growth difficulty.

Plants have been evolving（进化） alongside the insects that eat them for hundreds of millions of years. With that in mind, Heidi Appel, a botanist now at the University of Houston, and Reginald Cocroft, a biologist at the University of Missouri, wondered if plants might be sensitive to the sounds made by the animals with which they most often interact. They recorded the vibrations made by certain species of caterpillars（毛毛虫） as they chewed on leaves. These vibrations are not powerful enough to produce sound waves in the air. But they are able to travel across leaves and branches, and even to neighbouring plants if their leaves touch.

They then exposed tobacco plant—the plant biologist's version of the laboratory mouse—to the recorded vibrations while no caterpillars were actually present. Later, they put real caterpillars on the plants to see if exposure had led them to prepare for an insect attack. The results were striking. Leaves that had been exposed had significantly higher levels of defensive chemicals, making them much harder for the caterpillars to eat. Leaves that had not been exposed to vibrations showed no such response. Other sorts of vibration—caused by the wind, for instance, or other insects that do not eat leaves—had no effect.

"Now speakers with the right audio files are more often being used to warn crops to act when insects are detected but not yet widespread," says Dr. Cocroft. "Unlike chemical pesticides, sound waves leave no dangerous chemicals."