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The sloth’s popular image as a lazy creature that sleeps for most of the day has been called into question.

Rather than snoozing for more than 16 hours a day, as observed in captivity, sloths in the wild doze for less than 10 hours, research suggests.

Scientists caught sloths living in the rainforest of Panama and fitted them with a device that monitors sleep.

The findings, published in a Royal Society journal, may help shed light on human sleep disorders, they say.

Lead researcher Niels Rattenborg, of the Max Planck Institute for Ornithology in Starnberg, Germany, said the study demonstrated for the first time that it was possible to record sleep in a wild animal.

“The real exciting finding was that they only slept 9.6 hours a day, which is much less than what people popularly believed and less than had been observed in a previous study of sloths in captivity,” he told BBC News.

“So they still may be sloth-like in terms of their speed of movement but in terms of their sleep they don’t seem to sleep an inordinate amount of time.”

The work, published in the Royal Society journal Biology Letters, attempts to find traits that predict whether an animal sleeps more or less than another species. This might provide clues to the function of sleep, said Dr Rattenborg.

He added: “I think this finding is really going to open the door to a whole new age of sleep research on animals sleeping in their natural habitat.”

Proof of principle

Animals vary in the amount of sleep they need. Pythons, for example, sleep for 18 hours a day, while giraffes survive on just two hours.

To investigate sleeping patterns in wild sloths, the scientists, from Germany, Switzerland and the US, developed a small machine capable of monitoring brain patterns associated with sleep.

They caught three female brown-throated three-toed sloths living in rainforest near the Smithsonian Tropical Research Institute on Barro Colorado Island, Panama.

The animals were fitted with the data recorder and then released.

When re-captured several days later, measurements showed that they slept for an average of 9.6 hours a day, compared with a sleep time of 16 hours a day reported in sloths kept in captivity.

Dr Neil Stanley, an expert in sleep disorders at the Norfolk and Norwich University Hospital, UK, said animals tended to sleep much more in captivity, where they have all their needs met.

“It’s intuitive that animals would sleep less in the wild than in captivity - this technology gives us the opportunity to prove that’s true,” he said.

Despite many years of research into the function of sleep, there are still many unresolved questions.

It is known that sleep plays an important role in maintaining normal mental functions, but the precise mechanisms are unclear.

The designer of Apple’s iPod and one of the biggest names behind Bluetooth chip technology have received honours from the Royal Academy of Engineering.

Jonathan Ive, Apple’s vice-president of industrial design, won the coveted President’s Medal for his contribution in promoting engineering excellence.

The UK’s engineering body also awarded CSR the prestigious MacRobert award for its single-chip BlueCore technology.

The £50,000 MacRobert Prize rewards innovative technology and engineering.

The awards ceremony, dubbed the “engineering Oscars”, also included other medals recognising British engineering prowess and achievements.

They were handed out at a ceremony in London which was attended by the UK government’s minister for science, Lord Sainsbury.

Cambridge company CSR beat three other finalists to the top MacRobert Prize, including a sea-floor mapping system that spots oil and gas deposits, saving millions in exploratory drilling.

Other finalists included a mobile phone tracking program that pinpoints emergency callers and maps traffic jams, and a revolutionary fibre laser.

CSR’s key technology breakthrough in the late 1990s was to create a silicon chip with an integral radio transmitter.

“It sounds easy but in fact the ‘noise’ of the electrical signals on a tiny electronic chip would normally swamp a radio receiver working with micro-volt signals, and at the time it was thought to be impossible,” said Dr Phil O’Donovan, CSR’s co-founder.

They found a way around the problem by managing frequencies so that radio signals could communicate through the noise of a silicon chip’s digital traffic.

This is akin to the “cocktail party” effect, where certain voices can be heard over the crowd.

Blue everywhere

Its BlueCore technology is in millions of consumer electronics, such as personal digital assistants, laptops and mobiles, which need short-range communication capability.

Bluetooth is becoming increasingly important in helping different devices talk to each other wirelessly, such as hands-free headsets.

It is also being used more by the fashion industry, such as sunglass maker Oakley and snowboarding clothes maker Burton.

Having wireless capability built into clothing and accessories means people can use devices such as mobiles more easily whilst on the move or otherwise occupied.

CSR, widely recognised as the global leader in Bluetooth, is what is called a “fabless” company.

This means it focuses on the design and development of its Bluetooth micro-processors, then forms alliances with silicon wafer manufacturers and foundries who make them.

It has designed over 30 types of BlueCore silicon chips. Since 1999, 75 million of its chips have been sold and used in over 60% of all Bluetooth-enabled devices.

The President’s Medal is given on an ad hoc basis to people or organisations who have made significant contributions to the academy’s aims of promoting engineering excellence, but who are not eligible for election to the academy.

Mr Ive’s iPod engineering and design has made the device the biggest-selling portable digital music player in the world.

It dominates 80% of the music player market; by the end of 2005 more than 35 million iPods will have been shipped.

Other awards on the night included the Academy’s first ever Lifetime Achievement prize which was given to Dr Philip Woodward, retired deputy chief scientific officer, for his pioneering work on radar.

He was also behind one of the UK’s first electronic computers (TREAC) followed by the UK’s first solid state computer (RREAC).

Airport security staff could get extra hi-tech help in spotting suspicious luggage with new X-ray displays that can switch from 2D to 3D in an instant.

The displays by Sharp Labs mean staff can see realistic 3D images from X-rays without wearing cumbersome glasses.

3D displays have already been used in the likes of laptops, medical X-rays and mobiles, but being able to switch would be a first for airport X-rays.

It is one of four finalists for the eminent MacRobert engineering award.

The prize is given out by the UK’s Royal Academy of Engineering for technological and engineering innovation, on 10 June.

Treble vision

“The 3D technology we have developed aims at mimicking how people see 3D using natural vision,” Dr Grant Bourhill, from Sharp’s optical imaging labs, told BBC News Online.

“We try to send one image to one eye and a slightly different one to the second eye. We achieve that by using the ‘parallax barrier’ technique.

“The barrier is placed either behind or in front of a conventional crystal display which shows how the image is displayed to the viewer’s eyes.”

The parallax barrier has been known about for many years, but Sharp’s key innovation was finding out how to turn off the barrier, or the 3D effect, to leave a perfect 2D display.

The barrier works with polarisation optics and a simple electronic switch can be operated manually or by software, says Dr Bourhill.

“The right and left eye image is interlaced on the display screen. The function of the parallax barrier is to separate those images to two separate locations on the screen.

“The right eye will see the right eye image and the left eye will see the left eye image so your brain will perceive 3D just like normal vision.”

Already developed for mobile phones and laptops since last year, the displays will bring major benefits to airport security staff.

Bulky goggles

Conventional security X-ray systems, increasingly important in airport security in light of current terrorism concerns, use flat 2D displays. To view in 3D, they need to wear special eyewear.

Looking at objects in 2D makes it difficult to judge what is being viewed. With 3D technology, an object’s depth and height is seen more clearly so staff can make better decisions about it.

With easily switchable displays, the likelihood of false alarms is reduced, explains Dr Bourhill, detection rates are improved, as well as the speed and efficiency of luggage screening.

Being able to switch from 2D to 3D electronically does away with the need for the bulky and expensive goggles.

“A key part of the process was that our engineers from Oxford spent nine months in Japan actually transferring the technology developed in the UK to a state that was appropriate for mass manufacturing in Japan,” said Dr Bourhill.

“We are delighted to have been selected as one of the four finalists of one of the most prestigious engineering awards.”

Sharp is currently in discussions with a UK-based company to put the switchable displays into use at airports.

Although 3D displays have useful applications in games, photography, medical imaging, security and computer-aided design, the need to have a choice of swapping between 2D or 3D is a bonus, says Dr Bourhill.

The other finalists for the MacRobert award include self-cleaning glass, an eco-friendly fuel-injection system, and software that connects multiple system computer platforms.

The winner of the £50,000 prize money will be announced on Thursday and the prize will be awarded by HRH the Duke of Edinburgh.