Kiwi researchers have recreated what is thought to be the first computer-generated Christmas music – exactly as it would have sounded on Alan Turing's computer.
In a world-first, University of Canterbury Distinguished Professor Jack Copeland and composer Jason Long restored a historic 66-year-old recording believed to be the earliest surviving computer music, and they have now recreated two historic computer-generated Christmas carols.
The researchers recreated the computer-generated Yuletide music by using notes from the 66-year-old recording, which was generated in the Manchester computer lab run by Turing, the British computer scientist famous for breaking the Nazi Enigma code in World War II and portrayed by Benedict Cumberbatch in 2014's The Imitation Game.
"The idea started when I found a reference in old material to the BBC doing a Christmas broadcast in 1951 containing some carols played by Turing's computer in Manchester," Copeland said.
"Jason and I decided to recreate these. I found it amazing to hear that long-lost – and so historic – sound source belting out enjoyable festive music," he said.
"It will be great if our recreations find their way onto the Christmas playlists of some radio stations internationally."
Among its Christmas fare, the BBC broadcast in 1951 two melodies that, although instantly recognisable, sounded like nothing else on earth.
They were Jingle Bells and Good King Wenceslas, played by the mammoth Ferranti Mark I computer that stood in Alan Turing's Computing Machine Laboratory, in Manchester.
"According to Ferranti's marketing supremo, Vivian Bowden, it was 'the most expensive and most elaborate method of playing a tune that has ever been devised'.
"Bowden may have kicked himself for predicting, at this seminal moment, that computer-generated music had no future."
The researchers advise there are a few "dud notes" in the recreated carols: "Because the computer chugged along at a sedate 4 kilohertz or so, hitting the right frequency was not always possible.
"It's a charming feature of this early music — even if it does in places make your ears cringe."
Why tailgaters ruin our roads
We've all experienced that moment when we hit motorway congestion, only to see it quickly vanish again.
We scan for broken down vehicles or car accidents, but nothing.
Now, researchers say we wouldn't have to put up with these "phantom" traffic jams if drivers didn't tailgate.
In fact, MIT scientists say that if we all kept an equal distance between the cars in front of and behind us - or "bilateral control" if you want to call it by its technical term - we'd all get where we're going almost twice as quickly.
"We humans tend to view the world in terms of what's ahead of us, both literally and conceptually, so it might seem counter-intuitive to look backwards," Professor Berthold Horn said.
"But driving like this could have a dramatic effect in reducing travel time and fuel consumption without having to build more roads or make other changes to infrastructure."
Yet Horn conceded that drivers themselves were unlikely to change their forward-looking ways anytime soon, so he suggested that car companies update their adaptive cruise-control systems and add sensors to both their front and rear bumpers.
Traffic would get noticeably better, he argued, even if just a small percentage of all cars were fitted with such systems.
In future work funded in part by Toyota, he planned to do simulations to test whether this method is not just faster for drivers, but also safer.
The team's work has been inspired in part by how flocks of starling birds move in tandem.
"Birds have been doing this for centuries," Horn said.
"To programme this behavior, you'd want to look at the birds all around you and not just the ones in front of you."
For decades, there have been hundreds of academic papers looking at the problem of traffic flow, but very few about how to actually solve it.
One proposed approach was to electronically connect vehicles together to co-ordinate their distances between each other.
But so-called "platooning" methods require detailed co-ordination and a massive network of connected vehicles.
In contrast, the MIT team's approach would simply require new software and some inexpensive hardware updates.
Horn first proposed the concept of "bilateral control" five years ago, at the level of a single car and the cars directly surrounding it.
In a new study, he has taken a more macro-level view, looking at the density of entire highways and how miles of traffic patterns can be affected by individual cars changing speeds, or what he called "perturbations".
"Our work shows that, if drivers all keep an equal distance between the cars on either side of them, such 'perturbations' would disappear as they travel down a line of traffic, rather than amplify to create a traffic jam."
The science of ... lattes
If you've ever marvelled at the richly coloured layers in a cafe latte, you're not alone.
Researchers at Princeton University in the US, likewise intrigued, have now revealed how this tiered structure develops when espresso is poured into hot milk.
"The structure formation in a latte is surprising because it evolves from the chaotic, initial pouring and mixing of fluids into a very organised, distinct arrangement of layers," said Nan Xue, lead author of a new paper published in the journal Nature Communications.
Honing techniques for yielding sought-after layers by flowing liquids into each other could reduce costs and complexity in a range of applications.
"From a manufacturing perspective, a single pouring process is much simpler than the traditional sequential stacking of layers in a stratified product," co-author Professor Howard Stone said.
"In one application of this study, we are exploring the physics behind making a whole layered structure with one step, rather than one-by-one stacking of the layers."
The inspiration for the research project came from an unsolicited, emailed picture of a layered coffee drink sent to Stone.
With Xue looking for a project to take on as he started his graduate work, he initially investigated the concept by preparing lattes in the lab, using store-bought coffee and milk.
After several tries, it became clear to Xue that staying within only certain parameters, such as temperatures and pour rates, allowed for a characteristic cafe latte.
These efforts hinted at the underlying, quantifiable physics that had to be involved in its liquid structure formation.
To more precisely control their model of latte layering, Xue and colleagues opted for a stand-in recipe that would make a barista shudder: dyed water substituting for the hot coffee, and salty, denser water for the warm milk.
A panel of light-emitting diodes and a camera then illuminated and captured the movement of fluids within the concoction.
The researchers seeded the mixture with tracer particles, which scattered light from a green laser beam, to further track the faux-latte's internal dynamics, a technique called particle image velocimetry.
Finally, numerical simulations were run to compare the collected data with various models of the evolving system of intermixing liquids.
The overall analysis showed that the primary mechanism behind the layering is a phenomenon known as double-diffusive convection.
It occurred when stacked-up fluids of different densities, impelled by gravity to mix their contents, exchange heat through the movement of their constituent materials.
Within a given mixture, denser, cooler liquids sink, while lighter, hotter liquids rise. This sinking and rising stops, however, when the local density in a region within a latte approaches an equilibrium.
As a result, the fluid there has to flow horizontally, rather than vertically, creating distinct bands, or layers.
Through their experiments, the researchers examined how the velocity of the fluid injection of the warm milk matters as well.
If poured too slowly, the denser fluid will mix too evenly as it flows into the less-dense fluid.
A faster pour rate causes the former to punch through the latter and trigger the rapid movements that culminate in the desired layering when density equilibria were established.
More work needed to be done to characterise the layering effect demonstrated in lattes to extend control of it to other levelled liquids and semi-solids.
But the preliminary findings showed how the activity within a common beverage could lead to uncommon insights.
"This result shows the beauty of fluid mechanics and is very significant," said Professor Detlef Lohse, a fluid mechanics expert from the University of Twente in the Netherlands.
"I think it will have bearing on various industrial flows and mixing procedures in so-called process technology, in which mixing of fluids with different densities by the injection of one into the other is omnipresent."