Clips – Page 18 – Jennifer Carpenter

Elastic electronics see better

Venue: BBC

November 20, 2009 January 27, 2018

A new camera designed with a curved detection surface allows imaging devices to see as animals do.

The camera, inspired by the human eye, relies on the ability to construct silicon electronics on a stretchable membrane.

In the future, these electronic membranes could be wrapped around human organs to act as health monitoring devices, say US-based developers.

The new technology is described in a paper in the journal Nature.

Photosensitive displays – like the ones used in digital cameras – are made up of thousands of pixels and are usually formed on a flat, rigid, semiconductor wafer, explained Dr John Rogers from the University of Illinois at Urbana-Champaign, US, who led the team of researchers.

“No animal’s eyes are like that; the retina is curved,” Dr Rogers said.

“This curvature allows animals to see the world without distortion – unlike the images produced from cameras, which lose focus at the periphery.”

Hoping to improve digital imaging, the Illinois-based researcher and his team, joined up with a group of mechanical engineers from Northwestern University, to make a camera shaped more like an eye.

The challenge was to import the thin, brittle wafer-based camera technology to a curved surface. The result was a 2cm-wide camera with a single, simple lens and a concave light detection system.

Wafer-thin

The team approached the initial problem by dicing up the surface of the silicon wafer into “chiplets” – tiny pieces of silicon that detect incoming light.

The technology could be used to make an advanced pacemaker

Then, the world’s smallest cables, only one micron thick – the equivalent of 1/100 of the thickness of a human hair – provided the electrical connections between the adjacent chiplets to make a circuit.

Dr Rogers explained that if you squeeze the circuit, the cables allow the chiplets to move relative to each other.

Next, the team developed a curved elastic membrane.

Dr Rogers said that they had grabbed the edges of the membrane, pulling it in all directions, until taut and flat. Then the researchers dropped the mesh-like circuit of “photoreceptors” onto its surface.

“We released the membrane, let it snap back and saw that it puts all the photosensitive chips into compression,” Dr Rogers said.

“The ribbons pop-up, forming bridges between the chiplets, and so maintain the electrical connections.”

Flexible imaging

He added: “The interconnected mesh allows you to stretch, deform and reshape the circuit of photoreceptors [giving you an undistorted image].”

This is the first time anyone has moved electronics off rigid semiconductor wafers on to a fully flexible surface. The applications for this “flexible, stretchable” technology are vast, Dr Rogers told BBC News.

The photoreceptors could be swapped for any other type of receptor, and the whole circuit integrated into the human body for health monitoring.

“Look at the human body; there is nothing rigid about it,” says Dr Rogers.

His team is already developing circuits that contain electrodes, housed in the same membrane, to wrap around portions of the brain in people suffering from epilepsy, to act as an early warning system for seizure.

This technology could also be used in the heart to emit tiny electrical signals, acting as a very advanced pacemaker.

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Ancient shark had colossal bite

Venue: BBC

November 20, 2009 January 27, 2018

The great white shark may have awesome jaws but they are nothing compared with those of megalodon, its gigantic, whale-eating ancestor.

A new study of the extinct creature’s skull shows it had an almighty bite, making the prehistoric fish one of the most fearsome predators of all time.

All the more remarkable, scientists say, because the crushing force came from jaws made of cartilage, not bone.

The researchers report their skull work in the Journal of Zoology.

The Carcharodon megalodon super-shark swam in the oceans more than a million-and-a-half years ago.

It grew up to 16m (52ft) in length and weighed in at 100 tonnes – 30 times heavier than the largest great white – and must have been one of the most formidable carnivores to have existed.

“Pound for pound, your common house cat can bite down harder, ” explained Dr Stephen Wroe of the University of New South Wales, Australia. “But the sheer size of the animal means that in absolute terms, it tops the scales.”

Measuring up

Dr Wroe’s team used a technique known as finite element analysis to compare the skulls of the great white with that of the prehistoric megalodon.

The approach is a common one in advanced design and manufacturing, and allows engineers to test the performance of load-bearing materials, such as the metal in the body and wings of an aeroplane.

CT (X-ray) scans were taken of megalodon remains to construct a high-resolution digital model.

A model of a modern 2.4m-long male great white shark (Carcharodon carcharias) was developed for comparison.

A recent BBC series imagined a face-to-face encounter

The model of Megalodon’s muscles was based on those of the great white, and the simulations were then loaded with forces to see how the two skulls, jaws, teeth and muscles would have coped with the mechanical stresses and strains experienced during feeding.

By looking at the distribution of stress and strain on the sharks’ jaws, researchers found that the largest great whites have a bite force of up to 1.8 tonnes, three times the biting force of an African lion and 20 times harder than a human bites.

Megalodon, though, is more impressive. It is estimated to bite down with a force of between 10.8 to 18.2 tonnes.

The team said biting with such force was quite a feat given that the jaws of these ancient creatures were made of flexible cartilage.

In contrast to most other fish, sharks’ skeletons are made up entirely of cartilage. Scientists think that cartilage, being a much lighter material than bone, is one adaptation that allows sharks to swim without the aid of a swim bladder.

With finesse

The Australian research team was interested in how a cartilaginous jaw performs compared with a bone jaw.

The scientists’ study shows that the cartilaginous jaw is almost as strong as a bony jaw of the same size – losing only a few percent – in measures of bite force. What is more, the elasticity of the cartilage jaw increases the gape of the sharks to devastating ends.

“The shark’s upper jaws can be dislocated: the whole upper and lower jaw pull out and forward as the shark twists and shakes its head from side to side to bite a chunk out of its prey,” explains Dr Wroe.

These sharks feed on very large prey: the great white shark eats sea lions and the megalodon is thought to have eaten whales.

“These sharks ambush their prey and immobilise them with a bite, then wait for them to die,” Dr Wroe told BBC News. “They are actually delicate feeders and take care not to damage their teeth by biting down too hard on the large bones of their prey.”

To keep their teeth sharp, sharks have a battery of them that is continually replaced.

It is the combination of their size, their razor-sharp teeth and the element of surprise that makes these sharks such deadly predators.

MEGALODON COMPARED WITH THE GREAT WHITE SHARK


	Megalodon	Great white shark
Type	Cartilaginous fish	Cartilaginous fish
Size	16m (52ft)	6m (20ft)
Diet	Whales, including the now extinct Odobenocetops, seals	Fish, turtles, seals, sea lions, squid and crustaceans
Predators	None known	Occasionally caught by fishing industry as bycatch

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Pet dogs can ‘catch’ human yawns

Venue: BBC

November 20, 2009 January 27, 2018

Yawning is known to be contagious in humans but now scientists have shown that pet dogs can catch a yawn, too.

The copying activity suggests that canines are capable of empathising with people, say the researchers who recorded dogs’ behaviour in lab tests.

Until now, only humans and their close primate relatives were thought to find yawning contagious.

The team – from Birkbeck College, University of London – reports its findings in Biology Letters.

Yawning, although sometimes a response to extreme stress, is more often a sign of tiredness; but the reason for why yawning is catching is not fully understood.

Human cues

There is evidence that autistic individuals are less inclined to yawn into response to another human yawning, suggesting that contagious yawning betrays an ability to empathise, explained Birbeck’s Dr Atsushi Senju.

Dr Senju and his team wondered whether dogs – that are very skilled at reading human social cues – could read the human yawn signal, and set out to test the yawning capabilities of 29 canines.

The team created two conditions, each five minutes long, in which a person – who was a stranger to the dog – was sat in front of the animal and asked to call its name. Under the first condition, the stranger yawned once the dogs had made eye contact with them.

“We gave dogs everything: visual and auditory stimulus to induce them to yawn,” Dr Senju, told BBC News.

Under the second condition, the same procedure was followed, but this time the stranger opened and closed their mouth but did not yawn.

This was a precaution to ensure that dogs were not responding to an open mouth, explained Dr Senju.

Yawning yet?

The team found that 21 out of 29 dogs yawned when the stranger in front of them yawned – on average, dogs yawned 1.9 times. By contrast, no dogs yawned during the non-yawning condition.

The researchers believe that these results are the first evidence that dogs have the capacity to empathise with humans; although the team could not rule out stress-induced yawning – they hope to in future studies.

“Dogs have a very special capacity to read human communication. They respond when we point and when we signal,” Dr Senju told BBC News.

The researchers explained that along with floppy ears and big soppy-eyes, humans have selected dogs to be obedient and docile. The results from this study suggest the capacity for empathy towards humans is another trait selected in dogs during domestication.

Dr Senju thinks that these traits would have been useful to humans when they began to live side-by-side with canines approximately 15,000 years ago.

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Sub to make deep Caribbean dive

Venue: BBC

November 20, 2009 January 27, 2018

Scientists are set to explore the world’s deepest undersea volcanoes, which lie 6km down in the Caribbean.

Delving into uncharted waters to hunt for volcanic vents will be Autosub6000, Britain’s new autonomously controlled, robot submarine.

Once found, the life, gas and sediment around the vents – the world’s hottest – will be sampled and catalogued.

The research will be carried out by a British team aboard the UK’s latest research ship, the James Cook.

“We are heading out on two expeditions, each close to a month long, to map the full length of the Cayman Trough,” said team leader, Dr Jon Copley of the National Oceanography Centre in Southampton (NOCS).

Dr Copley explained that the Cayman Trough, which lies between Jamaica and the Cayman Islands, is a product of the Caribbean tectonic plate pulling away from the American plate.

“It is the world’s deepest volcanic ridge and totally unexplored,” the Southampton-based researcher told BBC News.

Along with Autosub6000, the researchers will also rely on Isis, the UK’s deepest-diving, remotely operated vehicle to scan the deep.

Double Sub

First overboard will be Autosub6000, an unmanned undersea vehicle that can go down to 6,000m and carry out a dive without being controlled from the surface.

It will be tasked with finding the volcanic vents on the ocean floor.

The second submarine to take the plunge will be the Isis.

Isis will sample fluids and sediments from around the lip of the vents to test their geochemistry, and also collect animal specimens.

Britain’s new robot sub will map the entire length of the Cayman Trough

“We are hoping to find several different types of vents along the ridge,” said Dr Copley.

“Some of the vents will be very similar in depth to the vents we already know about, and because the conditions will be alike, we might expect very similar animals,” he explained.

The researchers will look to compare the animals around the Cayman vents with those in the Atlantic and Pacific, in the hope of better understanding the processes that affect how deep-sea creatures “get about”.

If the organisms in the Cayman Trough look like those from other deep volcanic trenches, it will suggest that ocean currents must play a role in shaping the patterns of deep-sea life by transporting the animals’ larvae around.

However, if the Cayman Trough animals are very different from those existing in other parts of the Earth’s oceans then isolation will be considered more important.

“The deep ocean is our planet’s largest ecosystem. If we are going to use its resources responsibly then we need understand what determines its patterns of life,” the Southampton-based researcher said.

New vents

Dr Copley told BBC News that there was also another kind of venting that was driven by a very different geological process in which the Earth’s mantle is directly exposed to the water.

The researchers will explore vents looking for deep-sea animals

This type of volcanism has only ever been seen once before, in the mid-Atlantic.

The temperatures around these hydrothermal vents were so hot because they were so deep, Dr Copley said.

“They could be hotter than 500C (930F), and if they are that hot, they will probably have quite different chemistry and life forms – we expect to find new species.”

The researchers expect that, at depths greater than 3,000m, one in every two animals they come across will be a species new to science.

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Arsenic-munching bacteria found

Venue: BBC

November 20, 2009 January 27, 2018

In the warm, bubbling pools of Mono Lake in California, scientists have isolated a bacterium that fuels itself on arsenic.

Combining light and arsenic, these bacteria make their food and multiply using a chemical that is toxic to most other life forms.

The researchers think using arsenic as an energy source was a process used by ancient bacteria.

Their findings are reported in the journal Science.

Ronald Oremland of the US Geological Survey explained that these bacteria are photosynthetic, using sunlight – like plants – to turn carbon dioxide into food.

What is different about them is that instead of using water in this process, they use arsenic.

The US-based researchers isolated the bacterium from the lake, which lies at the foot of the Sierra Nevada.

Colour film

“These lakes are fed by hydrothermal waters that leach out arsenic-containing minerals from the surrounding rocks,” Dr Oremland told BBC News.

The researchers noticed that the bacteria had colonised small, hot pools, forming colourful “biofilms”.

Bacteria living in Mono Lake, California can survive the high levels of arsenic

“We suspected that these bacteria were using arsenic to make a living, so we scraped the biofilms off the rock and studied them under laboratory conditions.”

By first withholding light, then arsenic, the team showed that the bacteria required both to grow.

This the first time an organism has been found that can use arsenic to photosynthesise under anaerobic conditions, Dr Oremland believes.

He suspects that this is an ancient ability in bacteria.

“We think that bacteria were photosynthesising before oxygen was present in the atmosphere,” he said.

Primordial niche

Understanding how arsenic is metabolised by bacteria could help scientists comprehend its damaging effects inside human cells.

Worldwide, 144 million people are exposed to toxic levels of arsenic in their drinking water.

It enters the body’s cells by diffusion; and once inside, it disrupts how they function by binding to their machinery, inactivating it, and disrupting the way energy is transported.

Long-term exposure can lead to skin disease and kidney and bladder cancer, and it is thought to stunt the intellectual development of children.

The most arsenic-contaminated regions are in India, Pakistan, and China, where soluble arsenic in ground waters is above the World Health Organization’s (WHO) suggested maximum safe level of 10 parts per billion.

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Southern seals sample salty seas

Venue: BBC

November 20, 2009 January 27, 2018

Elephant seals are helping scientists study temperature and salinity changes in the Southern Ocean.

Equipped with computerised tags, the seals can reach regions of the sea impenetrable to researchers during the harsh winter months.

The data, collected during the animals’ long dives under Antarctic ice, provide the best ever estimates for the rate of sea-ice formation.

The findings appear in the Proceedings of the National Academy of Sciences.

The tags measure position, salinity, and temperature, among other things, to form a “hydrographic profile” for each of the 58 seals fitted with a device.

“By using seals, we have increased the number of hydrographic profiles 30-fold,” said Jean-Benoit Charrassin, who is based in France’s Natural History Museum.

“What we know about the Southern Ocean is very limited, which makes predicting the formation of sea-ice difficult,” Dr Charrassin told BBC News.

“These animals are filling a ‘blind spot’ in our sampling.”

Plunging profile

Seals make excellent marine surveyors because they swim up to 100km a day and dive to depths of 2,000m (6600ft) during foraging trips.

Sea temperatures and salinity are measured by seal transmitters

Dr Charrassin told BBC News that seals returned to the surface to breathe about 60 times a day, spending three minutes, on average, bobbing there before descending again.

“Occasionally they stay long enough for the data loggers, atop their heads, to send the data via satellite,” explained the Paris-based researcher.

“On average, we can collect two profiles a day from each seal.”

Dr Charrassin said that by measuring the salinity of water beneath sea-ice, researchers could determine how quickly it formed.

“In the Antarctic, when seawater freezes to form sea-ice, the salt – usually suspended in the water – is ejected into the water beneath the ice,” he explained.

Previous measures of sea-ice – calculated by measuring the distances drifted by buoys over a three-week period – estimate that in August, it forms at a rate of 8-10cm (3-4in) per day.

Data collected by the seals allows better estimates and suggests that this rate is much lower – only 1cm (0.3 inches) per day.

Seals often drift down to the bottom, seeming to sleep on their way down.

Jean-Benoit Charrassin, SEaOS

Estimating the rate of formation of sea-ice is crucial to understanding ocean currents.

This super-salty water forms a dense layer below the ice and sinks.

The dense water then flows along the sea bottom into the ocean basins, forming part of the thermohaline circulation, a large-scale ocean current driven by global temperature and salt gradients.

This current helps redistribute energy and nutrients in the world’s oceans.

In the long-term, the researchers hope to continue using seals to help them monitor salinity levels in the Southern Ocean, and study the impact of global sea temperature changes on ocean currents.

Seal scoop

But what about the “furry oceanographers” themselves; what can tagging seals teach scientists about seal biology?

The data loggers, as well as measuring the seals’ environment, record diving depths and time spent at the sea-bottom, giving researchers a window into the seals’ deep-sea foraging behaviour.

“We wanted to understand the foraging ecology of elephant seals and study their role in the marine food web,” said Dr Charrassin.

“We think the seals [at the bottom] try to catch deep-dwelling animals like squid and fish – at these depths, the seals’ lungs and body can be compressed to overcome the great pressures at 2,000m,” he said.

South Georgian elephant seals represent about 50% of the 740,000 breeding population in the Sub-Antarctic

Differences in foraging behaviour might explain why the island populations of elephant seals on Kerguelen and Macquarie have seen large declines, while the 400,000-strong South Georgian population has remained stable since the 1950s.

The seals’ hydrographic profiles give more weight to this idea, showing that animals from Kerguelen generally feed on the Antarctic continental shelf, while South Georgian seals tend to feed in open ocean.

Further study into prey numbers in these different environments is needed to confirm the role of foraging behaviour in the decline of two of the three seal populations.

The research is a collaborative effort involving scientists from Europe, Australia and the US. It is part of the Southern Elephant Seals as Oceanographic Samplers (SEaOS) project that has been running for four years.

The scientists stress the animals are not bothered by the data loggers carried on their heads. The boxes are glued on to the fur of the seals and stay there for one year, until the animals moult.

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Food for Thought: delivering the promise of food processing

November 20, 2009 January 27, 2018

Humans have transformed raw ingredients into food since prehistoric times. But scientists are still looking for new ways to make food taste better and survive longer. Presenting their findings at a recent European Science Foundation (ESF) and European Cooperation in the field of Scientific and Technical Research (COST) conference, scientists show how new food technologies are changing European diets.

The industrial revolution brought the advent of modern food processing technology. Whether you credit the Frenchman Nicholas Appert in 1809, or British born Peter Durand in 1810, the invention of the tin can has revolutionised the way people eat. The motivation behind its invention was simple – make food last long. Two hundred years on, food scientists are still trying to improve the shelf life of food.

:: Read more at European Science Foundation ::

Far flung food: Europe’s distant diets

November 20, 2009 January 27, 2018

Across the European Union, food is travelling more, and not always in ways that make sense. Consider the chocolate covered waffle: Last year, Britain both imported 14,000 tonnes, and exported 15,000 tonnes. And it is not just waffles that are travelling further, as Europeans are eating – and importing – more food from outside the EU than ever before.

At a recent conference, funded by the European Science Foundation (ESF) and the European Cooperation in the field of Scientific and Technical Research (COST), scientists and policy makers gathered to consider the problems that face future European food supplies. One important area of research looks at where food comes from, and how that food gets from the field to the fork.

:: Read more at European Science Foundation ::

Watching what we eat: food systems in Europe

November 20, 2009 January 27, 2018

Food has never been more of a global commodity than it is today. But there is an urgent need to understand the problems that face future European food supplies within this global market. And so scientists and policy makers gathered in Budapest last week to push for a more holistic approach to the study of what Europeans eat.

The conference, supported by the European Science Foundation (ESF) and the European Cooperation in the field of Scientific and Technical Research (COST), looked at where food comes from, the ways in which it is processed, packaged and distributed, and how it is sold and eventually eaten.

:: Read more at European Science Foundation ::