WE'RE BACK! And in this first episode of our new series, a sponge for soaking up oil slicks, how dung beetles navigate by starlight, the world's largest jelly, the rebound effect, how dogs came to be, why DNA is the data storage medium of tomorrow. Plus, a heads-up on transparent electronics, including a device that will superimpose a map of the road ahead onto your glasses...
In this episode
01:28 - Oil-spill selective sponge
Oil-spill selective sponge
Imagine a sponge that will only suck up oil. Helpful for your washing up perhaps, but maybe also useful for mopping up bigger oil spills. Japanese researchers at the University of Kyoto have developed a material that looks like a marshmallow, but can suck up oil floating on water and then be squeezed out and reused.
To make the super specific sponge the team use long polymers with lots of small side chains that stick out. They make those up into a jelly and then dry it out to leave a squidgy material with air holes and pores where the water used to be, just like a sponge. The porous structure means the material is very light, so it floats on water, and means the marshmallow-like material has a large surface area for soaking up oil.
We all know oil and water don't mix, but there are other materials that don't like water but like oil. That's why, when the sponge is dropped onto oil and water, it only soaks up the oil, leaving behind clean water. Cleaning up large oil spills might be a way off yet, as the sponge can only be made in small quantities at the moment, but for garages, small spills and cleaning up chemistry labs, this little material might have a big future...
04:18 - Dung Beetles Navigate by the Light of the Milky Way
Dung Beetles Navigate by the Light of the Milky Way
Dung beetles are remarkable creatures. Not only does their way of life supply food from someone else's waste, but recent research has shown that their dung balls keep their feet cool on the hot desert sands.
But now, research published in the journal Current Biology also shows that Dung beetles navigate by the light of the Milky Way, becoming the first insects known to use the night sky in this way to orient themselves. In fact, it's the first evidence of any animal using the diffuse light from the whole Milky Way, rather than the stars themselves, as a navigational aid.
Dung beetles find a fresh pile of dung, take a pinch and roll it into a ball. They then must travel in a straight line away from the pile, or risk coming back round to it and having their dinner stolen. Under a starlit sky, they retain this ability and navigate a straight path. However, when it is overcast, and the stars are obscured, they lose their navigational skill. This inspired Marie Dacke and colleagues from Lund University and the University of Pretoria to design a series of experiments to find out how the beetles know which way to go.
They manufactured tiny cardboard caps, much like the blinders on race horses, to obscure the beetles' views of the sky. This made a significant difference to the route the beetles would travel. Even when a curtain was erected to block out all local landmarks that could be used for navigation, the most significant factor was their view of the sky.
To determine exactly what aspects of a starry sky were providing the navigational cues, they next took their volunteer beetles to the Johannesburg Planetarium, where they had full control over the sky overhead. This showed that the Milky Way itself, visible as a diffuse streak of light, was the most important factor, and the presence of individual stars made little difference.
Although this is, so far, a unique observation, the authors argue that there's no reason to think it's a unique strategy, citing some evidence of night time orientation in cricket frogs and stating:
"Although this is the first description of an insect using the Milky Way for their orientation, this ability might turn out to be widespread in the animal kingdom."
06:27 - Polymer can turn swimming pool to jelly
Polymer can turn swimming pool to jelly
Probably the most powerful gelling agent in the world - just one kilogram would be enough to turn an Olympic swimming pool into jelly in minutes - this amazing new substance, unveiled this week, is the first synthetic polymer molecule that can mimic the inherent rigidity of biological polymers such as collagen.
The material, a polyisocyanide, assembles into huge networks that trap water extremely efficiently. Alan Rowan, a materials chemist at Radboud University Nijmegen in the Netherlands and one of the scientists behind the discovery which has been published this week in Nature, is investigating medical uses for the resulting gel, such as a covering for wounds that can be removed simply by cooling it down.
10:35 - Energy Efficiency on the Rebound
Energy Efficiency on the Rebound
These days, most of us try to live a 'greener' life; we may drive a hybrid car, recycle all we can and reduce the number of flights we take.
And, on a national and international level, the energy question has taken centre stage, led by efforts to become more energy efficient.
But, are we all wasting our time? A growing number of economists believe that the environmental benefits of improving energy efficiency have been oversold, and that as a result of making systems more efficient, we could even see an increase in emissions.
This paradox is called the rebound effect, and an article on it in the New York Times prompted Yale environmental scientist, Kevin Gillingham, to write a piece in Nature.
Although Gillingham and his colleagues agree that the rebound effect is real, they believe that economists have overstated its impact and have therefore introduced nothing more than a distraction into the energy debate.
Energy is never straightforward - saving it always requires a compromise, and the rebound effect is an example of this. One manifestation of it occurs when a decrease in price results in a rise in demand.
Higher-efficiency cars certainly burn less fuel per kilometre, but studies have shown that this just results in people driving more ('direct' rebound). And those who save money through improved energy efficiency may then go on to buy another product which requires energy to manufacture ('indirect' rebound).
So the rebound effect is real, but the debate centres on quantifying it, by measuring the overall gain or loss due to energy efficiency. It is expected the lat¬est fuel-economy standards passed by the United States will reduce demand for oil there.
But because this will result in a global decrease in oil prices (supply and demand!), this reduction in US consumption may just be 'topped up' by an increase in consumption in other countries. Gillingham suggests that such decrease in global oil prices will actually reduce the incentive to produce it, so that overall, less oil will be produced. So, the debate on this issue rages on.
No-one seems to deny that the rebound effect is real, or that it makes energy-efficient policies less effective. What those on opposite sides of the fence fundamentally disagree on is the size of the effect.
Some economists suggest that fuel savings have increased driving by up to 30%, but Gillingham argues that in real terms, this number is much lower. Say you save money on your fuel per kilometre; if you then drive further, you don't actually save any money, and without this saving you're unlikely to 'treat' yourself to a new laptop.
People often feel flummoxed by energy issues, and this debate won't do much to help. But if the goal is to reduce greenhouse emissions, it's obvious that solely focussing on improving efficiencies is not the answer.
The key is to reduce consumption, and there is a whole other debate on how to do this. Based on the idea that people (and companies) respond more strongly to price than to efficiency when it comes to energy, some suggest a tax on energy generated from fossil fuels.
Others say that more global investment is needed to develop alternative, 'carbon-free' sources of energy. In reality, it may be that only a battle fought on all of these fronts simultaneously will provide any real solution to the energy crisis.
14:36 - Dog domestication DNA changes revealed
Dog domestication DNA changes revealed
A comparison of the genetic make-up of dogs and wolves has revealed the most crucial DNA changes that brought man's best friend into being.
Fossil evidence suggests that dogs were domesticated from wolves about 10,000 years ago.
Crucially, this is also the time when humankind began to swap their former nomadic lifestyles for a more urban existence underpinned by the development of agriculture, suggesting that the two might be connected.
Uppsala University scientist Erik Axelsson and his colleagues compared the genetic sequences of 12 wolves with 60 domestic dogs representing 14 different breeds.
The team combed the resulting DNA data looking for genome regions where the dogs and wolves were consistently different between the two species.
Thirty-six such regions, containing 122 genes, were identified. A large number of them are known to play a role in brain development, which fits with the behavioural differences between dogs and wolves.
But a surprise also emerged. A number of genes related to starch metabolism and glucose absorption were also very different in the dogs compared with their lupine cousins.
Specifically, while wolves - which eat only a carnivorous diet - have just two copies of a gene for digesting starch, which is found only in plant matter, dogs have up to 40 copies and express the gene at much high levels.
According to the team, this reflects an adaptation by dogs to scavenging from human waste dumps, which would have contained starch-rich foodstuffs.
Such leftovers would have become increasingly abundant ashumans eschewed hunter-gathering behaviours, embraced agriculture and established permanent settlements.
"Our findings suggestes that the development of agriculture catalysed the domestication of dogs," the team suggest in their paper, published this week in Nature.
New technologies and endangered species - Planet Earth Online
with William Sutherland, Cambridge University
54:12 - Can high-frequency sounds repel mosquitoes?
Can high-frequency sounds repel mosquitoes?
We'll have the answer on the nect Naked Scientists Show. Until then, what do you think?