Crowds can lead to people being crushed or trampled, but researchers in Saudi Arabia are developing an artificial intelligence system to

. First black and white images are reduced to pixelated outlines where more pixels suggest more people, though clothing can confuse the readings. Then infrared cameras read body heat. Data goes to a neural network that learns the characteristic features of crowd movement. When the team tested the system on footage of a hajj pilgrimage it produced results like those from human spotters. Although a hajj can bring a million or more people together, a system like this could be useful in places like railway stations and for watching crowds that form spontaneously, such as at marches and rallies. That could have interesting applications for traffic flow too.

MAKE MANY BONES: The neurosurgeon in Alabama needed to do a very tricky surgery attaching metal plates to neck bones without damaging the spinal cord. After making some CT scans, he turned to a desktop 3D printer and printed out the bones he'd be working on at actual size. With an actual model in hand he could order screws and plates that fit the 3D printed spine model, and work out how to direct the screws. Ultimately the surgery on Sophi the tiny Yorkshire Terrier took much less time than usual for such operations and has given Sophi back her freedom to play. Medical specialists of all kinds must find the possibilities of 3D printing very powerful.


FAST AND FAR: The 200 HP Voxan Wattman motorbike can reach 100 Kph in 3.4 seconds and has a top speed of over 160 Kph. That's not bad for an electric bike whose 12.8 kWh battery takes only 30 minutes to charge to 80% from a household socket. A full charge will take the bike almost 200 Km. This isn't a little shopping bike then.

SPRAY AND BREATHE: One way to kill pathogens, for example in commercial kitchens, is to use heat or dangerous chemicals such as chlorine. Another way is to use ozone which can kill things like like e-coli, salmonella, staph aureus and pseudomonas a. The Eco3Spray is a handheld spray bottle that converts tap water into ozone on demand using a diamond electrolytic process. Workers can spray ozone onto surfaces, leaving no residue, rather than handling hazardous chemicals. It sounds too easy.

TREASURE THE TECH: The technology we use today relies heavily on all kinds of metals. Researchers at Yale University studied how easy it would be to substitute other metals if one suddenly became unavailable, and the news was bad. For some widely used metals such as copper, chromium, manganese and lead, no good substitutes exist for their major uses. Rare earth elements, including the dysprosium needed for computers and wind turbines, europium and yttrium, used in flat panel displays, and thulium and ytterbium, used in laser technologies would also be extremely hard to replace. Their conclusion? We'd better make sure we recycle the metals we rely on — which makes good sense anyway.

Miraz Jordan,