A Pittsburgh-based robotics and engineering startup recently make Moonwalkers public, a pair of battery-powered shoes that it claims can boost walk speeds by up to 250%.

At first glance, Moonwalkers look like a pair of futuristic roller-skates, but there is actually a lot more to them than that. You're actually meant to walk with them the way you would with regular shoes or sneakers, letting the motorized wheels put a spring in your step. Powered by a state-of-the-art brushless DC motor(直流电机), this creative device is actually a platform that can be attached to a wide variety of footwear to significantly increase your walking speed up to a reported 7mph/11kph. For comparison, humans' average walking speed ranges from 2. 5 to 4 mph. The sensation of walking with the world's fastest shoes has been compared to that of walking on a 'moving walkway' in an airport.

Designed by Shift Robotics, an offshoot of Carnegie Mellon University, Moonwalkers consist of a 300W brushless motor in each 4. 2-lb (1. 9-kg) shoe that powers eight polyurethane wheels. There is also an AI-powered gearbox that increases or decreases speed according to data regarding the wearer's walk collected by a series of sensors. The shoes are also able to detect downhill movement to prevent accidents.

"Moonwalkers are not skates. They're shoes. The world's fastest shoes actually," Xunjie Zang, founder and CEO of Shift Robotics said. "You don't skate in them. You walk. You don't have to learn how to use them; the shoes learn from you." But do the world's fastest shoes work on uneven ground, or things like stairs? We all know how tricky those are for rollerskates. Well, apparently the designers took that into consideration and with a simple gesture, the wearer can lock the wheels so that they can walk up or down stairs as they would in regular footwear.

The first batch is expected to ship in March of 2023, at a retail price of $1,399. That's not cheap, but then again, this isn't your average pair of shoes; it's the world's fastest pair of shoes.

Sometime in 1885 or 1886,Arthur Conan Doyle was doodling(信手乱涂)on a sheet of paper. Inspired by Edgar Allan Poe's Auguste Dupin, he had the idea for a "consulting detective", who would also use "the Rules of Evidence" to catch his man. But what would he be called? "Ormond Sacker"? "Sherrinford Holmes"?

Had he settled on either of these alternatives, the modern-day fan clubs would be able to look closely through their magnifying glasses(放大镜) at that historic piece of paper at an exhibition opening at the Museum of London on Friday.

Sherlock Holmes: The Man Who Never Lived and Will Never Die is the first major show for the great detective since a Holmes display graced the Festival of Britain in 195. It's a winningly silly title: there are an unlimited number of men who never lived and will never die, and a very large number of fictional creations of whom the same could also be said. But you can see what they are getting at.

It is likely that the show should take place at the Museum of London. Holmes occupied perhaps London's most famous imaginary address—221B Baker Street—and Dr. Watson wrote that his "knowledge of the byways of London was extraordinary". In the form of his "Baker Street Irregulars", he even employed a street-level spy-network o the homeless. London is often described as another character in the stories.

But, as historian David Cannadine points out in a fine, questioning essay in a new book accompanying the exhibition, Holmes's London is actually only sketchily imagined in the stories. Conan Doyle grew up in Edinburgh, was educated in Lancashire and Austria, and lived in central London for less than a year before moving first to South Norwood, then in short order to Hindhead in Surrey and later to Sussex. To move Holmes around the capital, Conan Doyle used contemporary books of street maps and the London Post Office Directory. And he made all sorts of mistakes.

Also, before fan-fiction as we think of it now got under way, the Holmes stories led to a strange academic version of fan-fiction: Holmesians, taking a scholarly interest in the texts almost on the assumption that Holmes and Watson were real historical characters.

It should be noted that Conan Doyle himself didn't sweat the details. Everything from the location of Watson's old war wound to his marital situation and the address of his consulting room was distinctly patchy(东拼西凑的).

Holmes is, or might as well be, a magician. In this respect, the modern BBC TV adaptations—whose leaps of tricks I've seen complained about -- are in keeping with Conan Doyle's originals.

He's not the product, not any more, of a single author. And he's never going to be on the reader's level—nor that of his friend Dr. Watson. Conan Doyle's consulting detective is, made by the imaginations of others, a sort of god. And like all the best gods, he is— as the new exhibition's title indicates—both imaginary and everlasting.

Governments should stop the use of biofuels (生物燃料) and lift bans on genetic modification (转基因) of crops, a green campaigning group has urged, in the face of a growing global food crisis that threatens the developing nations.

The EU, the US and the UK are among countries that use biofuels compulsorily, usually mixed with petrol fuels, for road vehicles. But many of the biofuels used come from food crops, including wheat, maize and so on. The World Food Programme has warned that the rising prices of these food, which have been driven by a combination of the Covid pandemic, climate breakdown and the war in Ukraine, is generating a food crisis around the world.

In the UK, the renewable transport Fuel Obligation requires about 10% of the. fuels supplied by fossil fuel companies to be "sustainable", which in effect means biofuels. However, the amount that can come from food crops is at 4% at most, and will be reduced further to 2% in 2032. A UK government spokesperson said: "biofuels, and other renewable fuels, will continue to play an important part in helping to decarbonize transport and meet our climate goals. However, to help address the global food price crisis, we continue to promote waste-derived biofuels and are reducing the percentage of crop based biofuels that count towards supplier targets. "

RePlanet says that although the original reason for biofuels was as. a lower carbon alternative to fossil fuels, in fact, owing to the impact on food, the fertilizer and energy used to produce the grains and oils and the land converted to agriculture to produce biofuels, there is little carbon saving over fossil fuels. RePlanet also argues that rich countries should eat less meat to free up grain , and that prohibitions on the genetic modification of crops (GMF) should be lifted to achieve higher yields. If Europe doesn't look at finding evidence-based solutions, the outcome will be worse for the world's poor, for the climate and for nature conservation.