Dinosaurs ‘shrank’ to become birds


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Dinosaur lineageBody trait analysis shows the miniaturisation of theropods started about 50 million years before Archaeopteryx, the earliest bird, lived.

Huge meat-eating, land-living dinosaurs evolved into birds by constantly shrinking for over 50 million years, scientists have revealed.

Theropods shrunk 12 times from 163kg (25st 9lb) to 0.8kg (1.8lb), before becoming modern birds.

The researchers found theropods were the only dinosaurs to get continuously smaller.

Their skeletons also changed four times faster than other dinosaurs, helping them to survive.

Results from the study are reported in the journal Science.

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From dinosaur to bird


Explore the half bird, half dinosaur features of Archaeopteryx

Discover more about the fossil that changed everything

Watch presenter Ben Garrod explain why modern birds are the legacy of the dinosaurs

Previous work has shown that theropod dinosaurs, the dinosaur group which included Tyrannosaurus rex and Velociraptor and gave rise to modern birds, must have decreased in size at some point in their evolution into small, agile flyers.

But size changes frequently occurred in dinosaur evolution, so the research team members, led by Mike Lee, from the University of Adelaide, Australia, wanted to find out if the dramatic size reduction associated with the origin of birds was unique.

They also wanted to measure the rate of evolution in dinosaurs using a large data set.

The authors used sophisticated analytical tools – developed by molecular biologists trying to understand virus evolution – to study more than 1,500 dinosaur body traits coded from 120 well-documented species of theropod and early birds.

From this analysis they produced a detailed family tree mapping out the transformation of theropods to their bird descendants.

It traces evolving adaptations and changing body size over time and across dinosaur branches.

They found that the dinosaur group directly related to birds shrank rapidly from about 200 million years ago.

It showed a decrease in body mass of 162.2kg (25st 7lb) from the largest average body size to Archaeopteryx, the earliest known bird.

These bird ancestors also evolved new adaptations, including feathers, wishbones and wings, four times faster than other dinosaurs.

A broad-billed hummingbird (Cynanthus latirostris) in front of a tooth of a massive dinosaurian.Shrinking and new bird-like traits jointly influenced the transition of dinosaurs to birds, researchers say.

The researchers concluded that the evolution of the branch of dinosaurs leading to birds was more innovative than other dinosaur lineages.

The authors say this sustained shrinking and accelerated evolution of smaller and smaller body size allowed the ancestors of birds to develop traits which helped them to cope much better than their less evolved dinosaur relatives.

“Birds evolved through a unique phase of sustained miniaturisation in dinosaurs,” Mr Lee said.

“Being smaller and lighter in the land of giants, with rapidly evolving anatomical adaptations, provided these bird ancestors with new ecological opportunities, such as the ability to climb trees, glide and fly.

“Ultimately, this evolutionary flexibility helped birds survive the deadly meteorite impact which killed off all their dinosaurian cousins.”

‘No overnight transformation’

The researchers believe that miniaturisation and the development of bird-like traits had a joint influence on the evolution of the dinosaurs into today’s birds.

Professor Michael Benton, from the University of Bristol’s school of earth sciences, said: “This study means we can’t see the origin of birds as a sudden or dramatic event, with a dinosaur becoming a powered flyer overnight.

“The functions of each special feature of birds changed over time – feathers first for insulation, and later co-opted for flight; early reductions in body size perhaps for other reasons, and later they were small enough for powered flight; improvements in sense of sight and enlargement of brain – even a small improvement in these is advantageous.

“So perhaps it’s a long-term trend associated with deputation to a new set of habitats, in the trees, to avoid predation, and to exploit new food resources.”

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Article source: http://www.bbc.co.uk/nature/28563682

Goalkeepers’ penalty ‘flaw’ revealed


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Tim KrulDutch goalkeeper Tim Krul making a save in the penalty shoot-out win against Costa Rica

Goalkeepers facing penalty shoot-outs make a predictable error that could influence the outcome say researchers.

Psychologists studied videos from World Cups and European Championships between 1976 and 2012.

They found that after three kicks in the same direction, keepers were more likely to dive the opposite way on the next shot.

Luckily for them, penalty takers have so far failed to exploit this predictable pattern.

Four knockout games in the 2014 World Cup in Brazil were decided by penalties – a record shared with Italy in 1990 and Germany in 2006.

Gambling with the game

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If kickers were to identify non-random patterns in the goalkeeper’s behaviour, they could really win the match quite easily without even a perfect kick”

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Erman Misirlisoy

Goalkeepers were the heroes in this year’s shoot-outs with the likes of Brazil’s Julio Cesar and Tim Krul from the Netherlands making game winning saves at crucial moments.

While scientists have sought to define the perfect penalty in the past, this new study from researchers at University College London (UCL), tries to statistically evaluate goalkeeping patterns in shoot-outs.

They conclude that the keepers in these situations often fall prey to what’s termed the “gambler’s fallacy”.

The fallacy can be seen in the flipping of a coin. If there’s a run of “heads”, many people mistakenly believe there is then an increased chance that the next one will be “tails”.

The reality is that there is a fifty-fifty chance on every toss, regardless of the length of the sequence.

Julio CesarBrazil’s Julio Cesar saves from Chile’s Alexis Sanchez in a second round shoot-out

In their analysis the researchers found that almost every action, such as the sides of the goal that the kickers aimed for, and the way the goalkeepers dived, were random events.

Crucially the researchers found that the goalkeeper’s decisions were predictable after three kicks had gone in the same direction.

“After three, it starts to be more significant than chance,” said lead author Erman Misirlisoy, from UCL.

“Around 69% of dives are in the opposite direction to the last ball, and 31% in the same direction as last after three consecutive balls in the same direction.”

A good example of this was in the England Portugal Euro Championship quarter final in 2004. The game went to penalties, and the first three Portuguese players all aimed at the left of the goal.

On the fourth penalty, the English keeper, David James, went to the right. The next Portuguese player stayed left again and scored. Portugal won the shootout 6-5.

“If kickers were to identify non-random patterns in the goalkeeper’s behaviour, they could really win the match quite easily without even a perfect kick. They would just have to kick the opposite way,” said Erman Misirlisoy.

If players were to take a group decision to all kick the same way, the fourth penalty in the shoot-out should offer them their best chance of scoring.

However, the problem for penalty takers is that the expectation from the crowd and their team mates is that they will score.

This weight may explain why they don’t work together or communicate well as a group.

“Kickers are under enormous pressure, focussed on the moment of their own kick. Each individual kicker may not pay enough attention to the sequence of preceding kicks to predict what the goalkeeper will do next,” said co-author Prof Patrick Haggard.

Sergio RomeroArgentina’s Sergio Romero makes a vital save against the Dutch in this year’s World Cup

If goalkeepers want to improve their odds of saving shots they must resist the gambler’s fallacy. Their best bet would be to have planned a sequence of dives and to stick with it.

“The best point for the keeper is to become more random,” said Erman Misirlisoy.

“There is nothing from him to exploit and he is only going to open himself up to being exploited if he does produce a pattern.”

The one area of the goal that the psychologists didn’t examine is the centre.

“In our analysis we decided to leave out the middle as it is so rare. It’s less than 10% of cases, and goalkeepers remain in the middle only 2.5% of the time, so kickers could possibly exploit this by kicking down the middle more often.”

The study has been published in the journal, Current Biology.

Follow Matt on Twitter @mattmcgrathbbc.

Article source: http://www.bbc.co.uk/news/science-environment-28582630#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

Mystery of lemon-shaped Moon solved


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The Moon and EarthThe early Moon was closer to Earth than today, so its shape may have been changed by the tides

Scientists have worked out the reasons for the distorted shape of our Moon.

A US team calculated the effect on the shape of the early Moon of tidal and rotational forces.

Writing in Nature, they say its own spin and the tidal tug of the Earth created a “lemon-shaped” satellite.

Lead researcher Ian Garrick-Bethell, from the University of California Santa Cruz, said this shape-shifting occurred when the Moon was mostly liquid beneath a thin outer crust of rock.

This interaction with the Earth also caused the Moon to shift slightly on its own axis.

“For the Earth and Mars and other bodies, we know that the dominant shape of the planet is due to its spin,” he said.

“If you take a water balloon and start spinning it, it will bulge out at the equator, and on the Earth, we have something very similar to that.”

The Moon (c) SPL

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Professor of planetary sciences Ian Garrick-Bethell explains what gave the Moon its lemon-like distorted shape

This effect, however, does not explain how “surprisingly distorted” our Moon is.

“It’s spinning really slowly, and it’s really far from the Earth, so it’s not like tides today could be causing that.”

Prof Garrick-Bethell’s new explanation is that four billion years ago – when the Moon formed from the debris thrown out by a huge impact between early Earth and a so-called planetoid – was much closer to the Earth. This meant tides were stronger.

“The Moon was [also] spinning much faster,” he told BBC News.

“So there’s a variety of interesting things that could happen, at that time when the Moon was really hot, that could change its shape.”

Heating and stretching

When the Moon first formed, it was liquid rock. As it cooled, the outer crust solidified and floated on this viscous ocean.

The gravitational tug of the Earth raised tides on the Moon that started to “flex and pull on that thin crust”, said Prof Garrick-Bethell.

He and his colleagues were inspired in this idea by an earlier study of one of Jupiter’s moon’s Europa.

Europa has an ice crust floating on a liquid ocean of water.

In a 2013 study, researchers from the University of Texas at Austin calculated how tidal heating – caused by Jupiter’s tug on that warmer liquid water – was distributed in Europa’s icy shell.

Prof Garrick-Bethell’s team realised that a similar effect could have occurred in the liquid rock ocean on the early Moon.

They also solved the mathematical problems caused by large craters and basins on the Moon’s surface that formed after the crust solidified.

These have previously caused problems for past attempts to interpret its shape. They’re essentially chunks of “missing Moon” that make it difficult to map its co-ordinates and work out how its original spherical shape would have been rearranged.

“We did a lot of work to estimate the uncertainties in the analysis that result from those gaps [in the data],” Prof Garrick-Bethell said.

The result, the researchers claim, is the best explanation yet of the Moon’s odd shape.

Article source: http://www.bbc.co.uk/news/science-environment-28565730#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

Broody octopus keeps four-year vigil


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Deep-sea octopus and her eggsThe octopus tended her 160 eggs at a depth of 1.4km, keeping dirt away and flushing them with fresh water

For four years and five months, she clung to the rock and guarded her eggs.

In a feat that surely made good use of all eight arms, an octopus revealed a new secret of deep sea life when ecologists observed her record-breaking behaviour from a robotic submarine.

This doubles the longest brooding time ever seen in the animal kingdom, giving embryos time to develop in the cold.

The discovery, published in the journal PLOS One, was made in a canyon 1.4km beneath the Pacific, off California.

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It got to be like a sports team we were rooting for – we wanted her to survive and to succeed”

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Dr Bruce Robison
Monterey Bay Aquarium Research Institute

Dr Bruce Robison led the research at the Monterey Bay Aquarium Research Institute (MBARI). He told BBC News his team had stumbled upon the plucky mother in the days before she settled down and glued her eggs to the rock face.

She was heading, slowly, for a known brooding site.

By looking at characteristic scars in one of her eight armpits, the team identified the same octopus on the next dive, one month later.

Cheer squad

“The first time that we dropped back down… and realised that she had gone up and laid a clutch of eggs, it was very exciting,” Dr Robison said. “We knew that we had the beginning.”

“No-one had ever had the good fortune to come upon the beginning of a brooding period.”

That was May 2007 – Tony Blair was still in office and the world had only seen two Shrek movies.

Deep-sea octopus on a ledgeScientists first spotted the octopus heading for a brooding site on the rocks of the Monterey Canyon

For the next four and a half years, the team paid the devoted cephalopod 18 more visits, thanks to multimillion-dollar remote diving vehicles equipped with cameras, robotic arms, and laser lights to make physical measurements.

“Each time we went down it was more of a surprise,” Dr Robison said, “because we found her there again and again and again, past the point that anybody expected she’d persist.

“It got to be like a sports team we were rooting for. We wanted her to survive and to succeed.”

Octopus and eggs were all still firmly in place in September 2011. By October, the same month that David Cameron urged his government to support same sex marriage and the first Puss in Boots spin-off landed, she had disappeared.

Octopus egg husksAfter four years and five months, only empty egg cases were left behind

Empty egg cases littered the scene of her encampment.

Four-year fast?

The octopus probably died shortly after completing her vigil, according to Dr Robison. The brooding period typically takes up the final quarter of a female octopus’s life.

“She has only one job once those eggs are deposited,” he said.

He added she quite possibly ate nothing for the whole 53 months.

“Everything we know suggests she probably didn’t eat,” Dr Robison said. Most octopuses do not feed while brooding, he explained, and in countless dives his team had “never seen a clutch of eggs untended”.

The only time the cameras saw this particular devoted mother pay any attention to the crabs or shrimps that strayed nearby – normally a square meal for an octopus – was when she batted them away from her 150 precious eggs.

Even when the team used one of the submarine’s appendages to offer her a snack, they were resolutely ignored.

Deep-sea octopusThe cephalopod super-mum refused food and warded off predators for a record-breaking 53 months

Kerry Perkins, an aquarist at the Sea Life aquarium in Brighton, said a four-year fast was a possibility, but noted that the octopus may have got nutrients from unlaid eggs or very occasional, unobserved titbits.

“They’re exceptionally good mothers,” she said. “It is very, very cold water and they’re not moving much, so their metabolic rate would be pretty low – but still, you’d think in four and a half years you’d probably have to have a snack at some point.”

Eclipsed shrimp

Ms Perkins said she was “quite amazed” by the findings, which contribute to our still very rudimentary understanding of these deep-sea dwellers.

“They’re still very much the aliens of the sea.”

Dr Robison believes the icy temperature at these depths – about 3C – is what governs the extraordinary brooding routine.

Mysid shrimpThe previous brooding record was held by a giant red shrimp, which protects its eggs for 20 months

“The low temperature slows everything down,” he said. A low metabolism allows the mother to survive on little or no food, while she protects the eggs and flushes water over them, keeping their oxygen supply up as they gradually develop.

The previous record for the longest known brooding time was 20 months, and belonged to a giant red shrimp.

Article source: http://www.bbc.co.uk/news/science-environment-28545964#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

Tablet screens to correct sight loss


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computer glassesThe new development might mean the end of glasses at a computer

Engineers have developed a prototype tablet display that compensates for an individuals’ vision problems.

The system uses software to alter the light from each individual pixel on the screen, based on the person’s glasses prescription.

The researchers also added a thin plastic pin hole filter to enhance the sharpness of the image.

The team say the technology could help millions who need corrective lenses to use their digital devices.

Around one person in three in the UK suffers from short-sightedness or myopia. In the US, around 40% while in Asia it is more than half the population.

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Instead of relying on optics to correct your vision, we use computation”

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Fu-Chung Huang,
University of California

In recent years there have been a number of projects that have attempted to use computing screens to correct vision problems.

The authors of this latest study say their prototype offers “significantly higher contrast and resolution compared to previous solutions”.

Follow the light

The team from the University of California, Berkeley, working with colleagues at Massachusetts Institute of Technology (MIT), developed an algorithm that adjusts the intensity of each direction of light that emanates from a single pixel in an image, based on the user’s specific visual impairment.

Their prototype used an iPod, with a printed pinhole mask attached to the screen. To check the images, the researchers used a digital single-lens reflex (DSLR) camera which was set up to simulate a person who was farsighted.

blurOn the right is a computer simulation of the best picture quality possible using the new prototype display

The altered images from the iPod appeared sharp and clear to the camera, showing that the prototype was effective in correcting this sight issue.

“The significance of this project is that, instead of relying on optics to correct your vision, we use computation,” said lead author Fu-Chung Huang. “This is a very different class of correction, and it is non-intrusive.”

The research team believe that their idea, when refined further, could be of benefit to people who suffer from more difficult-to-treat vision issues.

“We now live in a world where displays are ubiquitous, and being able to interact with displays is taken for granted,” said Prof Brian Barsky, from UC Berkeley, the project leader.

“People with higher order aberrations often have irregularities in the shape of the cornea, and this irregular shape makes it very difficult to have a contact lens that will fit.

“In some cases, this can be a barrier to holding certain jobs because many workers need to look at a screen as part of their work. This research could transform their lives.”

Battery question

It should be stressed that while the research is at a very early stage, the engineers behind it the approach believe it has great potential, in the field of visual correction and beyond.

They envisage displays that users with different visual problems can view at the same time and see a sharp image.

“In the long run we believe that flexible display architectures will allow for multiple different modes, such as glass free 3D image display, vision corrected 2D image display and combinations of vision corrected and 3D image displays,” the authors write.

No consideration has been given, at this stage, to the impact such a system might have on the battery life of digital devices. This could also be an important factor going forward.

The research will be presented at an international conference on computer graphics called SIGGRAPH, in Vancouver in August.

Article source: http://www.bbc.co.uk/news/science-environment-28562432#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

Birds beat machines in hover test


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Anna's hummingbird (c) Lentink Group

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Prof David Lentink from Stanford University explains how slow-motion footage helped reveal the secrets of a hummingbird’s efficient flight

When it comes to flight, nature just has the edge on engineers.

This is according to a study comparing hummingbirds with one of the world’s most advanced micro-helicopters.

Researchers found that – in terms of the power they require to lift their weight – the best hummingbird was over 20% more efficient than the helicopter.

The “average Joe” hummingbird, however, was on par with the helicopter, showing “how far flight engineering has come”.

The findings are published in the Royal Society journal Interface.

Lead researcher Prof David Lentink, from Stanford University in California, explained that the flight performance of a hummingbird – the only bird capable of sustained hovering – was extremely difficult to measure.

“Imagine a 4g bird,” he said. “The forces they generate are tiny.

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Flapping and flying

Moth in flight (c) SPL

As birds and insects move through the air, their wings are held at a slight angle, which deflects the air downward.

This deflection means the air flows faster over the wing than underneath, causing air pressure to build up beneath the wings, while the pressure above the wings is reduced. It is this difference in pressure that produces lift.

Flapping creates an additional forward and upward force known as thrust, which counteracts the insect’s weight and the “drag” of air resistance.

The downstroke or the flap is also called the “power stroke”, as it provides the majority of the thrust. During this, the wing is angled downwards even more steeply.

You can imagine this stroke as a very brief downward dive through the air – it momentarily uses the creature’s own weight in order to move forwards. But because the wings continue to generate lift, the creature remains airborne.

In each upstroke, the wing is slightly folded inwards to reduce resistance.

“As a result the drag of a hummingbird wing has never been measured accurately.”

Drag is the force opposing the upward force of lift that birds’ wings generate by flapping.

Prof Lentink and his team wanted to understand if feathered hummingbird wings were more efficient – using less power to overcome drag – than the engineered blades of a helicopter of a similarly tiny scale.

He and his colleagues compared the birds’ performance to an advanced micro-drone called the Black Hornet – a 16g helicopter used for surveillance by British troops in Afghanistan.

To make the laboratory measurements, they used wings from hummingbird specimens kept in museums.

By putting these detached wings into an apparatus called a wing spinner, the team was able to measure exactly how much flapping power was required to lift the bird’s weight.

Prof Lentink’s colleagues at the University of British Columbia in Canada also made recordings of wild hummingbirds in flight, to measure the exact movement of their wings – which beat up to 80 times per second.

“By combining the wings’ motion with the drag [that we measured in the lab], we were able to calculate the aerodynamic power hummingbird muscles need to provide to sustain hover,” explained Prof Lentink.

One species – the Anna’s hummingbird – was champion hoverer, performing much more efficiently than the helicopter.

But on average, the birds hovering performance was “on par with the helicopter”.

“This shows that if we design the wings well, we can build drones that hover as efficiently, if not more efficiently, as hummingbirds,” said Prof Lentink.

“Clearly we are not even close to hummingbirds in many other design metrics, such as wind gust tolerance, visual flight control through clutter, to name a few.

Micro-drone in researcher's hand

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Dr Mirko Kovac from Imperial College explains how drones whose design is inspired by nature are set to become part of our everyday lives

“But if we focus on aerodynamic efficiency, we are closer than we perhaps ever imagined possible.”

Dr Mirko Kovac from the aerial robotics lab at Imperial College London said the study was a great example of research at the interface of biology and engineering.

“Studying hummingbird wing shapes can not only give insights into the biomechanics of animals,” he told BBC News, “but the gained insights can also be used to build the next generation of flying micro robots.”

Article source: http://www.bbc.co.uk/news/28563737#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

MPs bicker over climate report


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protestCampaigners demonstrated outside the meeting of the IPCC in Stockholm in 2013

MPs have endorsed the findings of a UN climate panel that says humans are the dominant cause of global warming.

Members of the Energy and Climate Change Committee said there was “no reason to doubt the credibility of the science” of the Intergovernmental Panel on Climate Change.

But two MPs, known for their sceptical views, voted against this conclusion.

They said the committee report was more like cheer leading than objective analysis.

The IPCC issued its latest assessment of the causes, impacts and solutions to climate science, in three parts, starting in September last year.

No reason for doubt

The panel’s key conclusion was that the scientists were 95% certain that humans were the “dominant cause” of warming since the 1950s.

But the IPCC has faced criticism about its relevance and methods after a number of small errors were highlighted in its 2007 report.

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What is starkly clear from the evidence we heard however is that there is no reason to doubt the credibility of the science”

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Tim Yeo MP
Chair, Energy and Climate Change Committee

The cross-party commons body heard from a range of experts and concluded that the panel had tightened its processes and the recent report was the most exhaustive and heavily scrutinised to date.

The panel was sound, the MPs held, and so were its conclusions.

“What is starkly clear from the evidence we heard however is that there is no reason to doubt the credibility of the science or the integrity of the scientists involved,” said Tim Yeo, MP chair of Energy and Climate Change Committee.

“Policymakers in the UK and around the world must now act on the IPCC’s warning and work to agree a binding global climate deal in 2015 to ensure temperature rises do not exceed a point that could dangerously destabilise the climate.”

Scientists involved with the IPCC were delighted with the endorsement.

reportThe third part of the IPCC report was published in Berlin in April

“I welcome the publication of this report which confirms unambiguously the robustness of the IPCC process and the science of climate change,” said Prof Rowan Sutton from the University of Reading, and a lead author on Working Group 1.

“The atmosphere and oceans are getting warmer; Arctic ice is melting and sea levels are rising. CO2 levels are at their highest for almost a million years, and it’s clear that man is to blame for these record levels.”

Uncertainties ignored

But two members of the committee, Peter Lilley (Conservative) and Graham Stringer (Labour), disagreed with the other nine.

They accused their fellow MPs of not holding the IPCC critically to account.

“As scientists by training, we do not dispute the science of the greenhouse effect – nor did any of our witnesses,” they said in a statement.

“However, there remain great uncertainties about how much warming a given increase in greenhouse gases will cause, how much damage any temperature increase will cause and the best balance between adaptation to versus prevention of global warming.”

The two MPs say that the underlying technical report of the IPCC acknowledges many uncertainties, but these have been omitted from the critical Summary for Policymakers, presented to politicians.

Among a number of issues they highlight the so-called “pause” in global warming since 1997.

“About one third of all the CO2 omitted by mankind since the industrial revolution has been put into the atmosphere since 1997; yet there has been no statistically significant increase in the mean global temperature since then.

“By definition, a period with record emissions but no warming cannot provide evidence that emissions are the dominant cause of warming!”

The Energy and Climate Change Committee, in their report, took a different view. They said that periods of hiatus are consistent with earlier assessments and forced climate change takes place against a background of natural variability.

“The current period of hiatus does not undermine the core conclusions of the WGI (working group 1) contribution to the fifth assessment report when put in the context of the overall, long-term global energy budget.

“Despite the hiatus, the first decade of the 2000s was the warmest in the instrumental record and overall warming is expected to continue in the coming decades.”

Follow Matt on Twitter @mattmcgrathbbc.

Article source: http://www.bbc.co.uk/news/science-environment-28531091#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

‘Quantum Cheshire Cat’ observed


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Cheshire CatThe Cheshire Cat mysteriously disappeared leaving only his mischievous grin

Scientists have for the first time separated a particle from one of its physical properties – creating a “quantum Cheshire Cat”.

The phenomenon is named after the curious feline in Alice in Wonderland, who vanishes leaving only its grin.

Researchers took a beam of neutrons and separated them from their magnetic moment, like passengers and their baggage at airport security.

They describe their feat in Nature Communications.

The same separation trick could in principle be performed with any property of any quantum object, say researchers from Vienna University of Technology.

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Start Quote

Well! I’ve often seen a cat without a grin, but a grin without a cat! It’s the most curious thing I ever saw in my life!”

End Quote
Alice’s Adventures in Wonderland

Their technique could have a useful application in metrology – helping to filter out disturbances during high-precision measurements of quantum systems.

Schrodinger’s paradox

In Lewis Carroll’s classic children’s story, the Cheshire Cat gradually disappears, leaving only its mischievous grin.

This prompts Alice to exclaim: “Well! I’ve often seen a cat without a grin, but a grin without a cat! It’s the most curious thing I ever saw in my life!”

The idea of a “quantum Cheshire Cat” was first proposed in 2010 by Dr Jeff Tollaksen from Chapman University, a co-author on this latest paper.

In the world familiar to us, an object and its properties are always bound together. A rotating ball, for instance, cannot become separated from its spin.

Cheshire CatThe cat (the neutron) goes via the upper beam path, while its grin (the magnetic moment) goes via the lower

But quantum theory predicts that a particle (such as a photon or neutron) can become physically separated from one of its properties – such as its polarisation or its magnetic moment (the strength of its coupling to an external magnetic field).

“We find the cat in one place, and its grin in another,” as the researchers once put it.

The feline analogy is a nod to Schrodinger’s Cat – the infamous thought experiment in which a cat in a box is both alive and dead simultaneously – illustrating a quantum phenomenon known as superposition.

To prove that the Cheshire Cat is not just a cute theory, the researchers used an experimental set-up known as an interferometer, at the Institute Laue-Langevin (ILL) in Grenoble, France.

A neutron beam was passed through a silicon crystal, sending it down two different paths – like passengers and their luggage at airport security.

By applying filters and a technique known as “post-selection”, they were able to detect the physical separation of the neutrons from their magnetic moment – as measured by the direction of their spin.

“The system behaves as if the neutrons go through one beam path, while their magnetic moment travels along the other,” the researchers reported.

Glimpsing this Cheshire Cat requires what quantum physicists call “weak measurement,” whereby you interact with a system so gently that you avoid collapsing it from a quantum state to a classical one.

Their delicate apparatus could have useful applications in high-precision metrology, the researchers say.

“For example, one could imagine a situation in which the magnetic moment of a particle overshadows another of the particle’s properties which one wants to measure very precisely.

“The Cheshire Cat effect might lead to a technology which allows one to separate the unwanted magnetic moment to a region where it causes no disturbance to the high-precision measurement of the other property.”

Article source: http://www.bbc.co.uk/news/science-environment-28543990#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

How faces drive first impressions


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elderly faceApproachable? Intelligent? People’s responses to 1,000 photographs were used to build the model

Whether it’s a curled lip or a keen cheekbone, we all make quick social judgements based on strangers’ faces.

Now scientists have modelled the specific physical attributes that underpin our first impressions.

Small changes in the dimensions of a face can make it appear more trustworthy, dominant or attractive.

The results, published in the journal PNAS, could help film animators or anyone looking to create an instant impression on a social network.

Dr Tom Hartley, a neuroscientist at the University of York and the study’s senior author, said the work added mathematical detail to a well-known phenomenon.

“If people are forming these first impressions, just based on looking at somebody’s face, what is it about the image of the face that’s giving that impression – can we measure it exactly?”

Positive first impressions are especially important in a world dominated by social media, from LinkedIn to Tinder.

Dr Hartley sees the commercial potential in applying his numerical model to the photos people use to present themselves online. “It’s obviously potentially very useful,” he told the BBC.

To make the calculations, each of 1,000 face photos from the internet was shown to at least six different people, who gave it a score for 16 different social traits, like trustworthiness or intelligence.

Overall, these scores boil down to three main characteristics: whether a face is (a) approachable, (b) dominant, and (c) attractive.

Cartoon smiling face

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Cartoon faces based on the new mathematical model, sliding along 3 scales: approachability, dominance and attractiveness

By measuring the physical attributes of all 1,000 faces and putting them together with those scores, Dr Hartley and his team built a mathematical model of how the dimensions of a face produce those three impressions.

The next step was to get the computer to extrapolate. Using their new model, the team produced cartoon versions of the most (and least) approachable, dominant and attractive faces – as well as all the possibilities in between.

Example facesSix faces and their computerised cartoon approximations, including study author Dr Tom Hartley (second from left)

Finally, and most importantly, these cartoon results could be tested. When the researchers quizzed more participants about their impressions of the artificial, cartoon faces, the ratings matched. People said that the computer’s cartoon prediction of an approachable face was, indeed, approachable – and so on.

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You could use these kind of numbers to decide when is a good time to take a photograph, or to choose the photograph that’s really optimal in putting forward the best possible impression”

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Dr Tom Hartley
University of York

So has all this work revealed humanity’s ultimate trustworthy jawline, or the most assertive shape for eyebrows? Dr Hartley is cautious.

“Lots of the features of the face tend to vary together,” he explained. “So it’s very difficult for us to pin down with certainty that a given feature of the face is contributing to a certain social impression.”

There are some obvious trends however – including the tendency for masculine faces to be perceived as dominant, or for a broadly smiling face to seem more approachable and trustworthy.

This points to a potentially worrying implication: brief facial expressions can make a big difference to how we are received by strangers.

“It might be problematic if we’re forming these kind of judgements based on these rather fleeting impressions,” Dr Hartley said, “particularly in today’s world where we only might see one picture of a face, on social media, and have to form our impression based on that.”

Cartoon facesA mathematical model produced cartoon faces based on how people rated various facial dimensions

On the other hand, the findings could help people put their best face forward.

“It might be very useful for organisations who are interested in people’s faces,” said Dr Hartley.

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[Being] approachable is tied to smiling expressions and unapproachable to frowning or angry expressions, while dominance is tied to masculine features”

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Dr Anthony Little
University of Stirling

That might include interests as diverse as photographers, Facebook and Pixar.

“You would be able to use these kind of numbers to decide when is a good time to take a photograph, or maybe to choose the photograph that’s really optimal in putting forward the best possible impression – and you might want to put forward different kinds of social impressions in different situations.”

Animators, on the other hand, “have to give life, and give some social meaning, to the faces of their characters just by changing small things,” Dr Hartley said.

“What we’re doing is trying to put that on a scientific footing. It’s been fascinating to find out more about it.”

Dr Anthony Little, a reader in psychology at the University of Stirling, said the findings point to something “simple and important” about the way physical attributes guide our social responses.

Silly faceImpressions included attractiveness and trustworthiness – potential mate or used car salesman?

“The results highlight that the way we see other people may be in relatively simple terms, as approachable/unapproachable and dominant/submissive,” said Dr Little, whose own research on faces and psychology includes using a website to crowd-source ratings.

“Each of these two factors looks to be tied to specific face features. So, approachable is tied to smiling expressions and unapproachable to frowning or angry expressions, while dominance is tied to masculine features.

“The third factor, youthful-attractiveness, appears less distinct.”

This is because of interplay between attractiveness and the other two factors, Dr Little explained.

Article source: http://www.bbc.co.uk/news/science-environment-28512781#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

Eggshells may act like ‘sunblock’


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Song thrush eggsBlue, white or spotted: Eggshell pigmentation may act as ‘sunblock’ controlling the light reaching embryos

The eggshells of wild birds may act like “sunblock”, scientists have said.

A range of UK birds’ eggs showed adaptations in pigment concentration and thickness to allow the right amount of sun to reach the embryos inside.

Researchers examined 75 species’ eggs kept in a museum collection.

“Embryos do need UV exposure to develop – too little and they don’t develop enough… too much and it causes damage,” said team member Dr Steven Portugal from the University of London.

“Birds whose nests are exposed to the sun and birds which have long incubation periods too, have more pigment and allow less light to go through the shell to avoid UV damage to embryos,” he explained.

The study, published online in the journal Functional Ecology, suggests thickness and pigment in eggshells change depending on the nest environment.

Wild birds’ eggshell colours can be white, blue and spotted. The blue colour found in many eggs is caused by a pigment called biliverdin, while dark spots are produced by a darker pigment, protoporphyrin.

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Eggs (c) BBC

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The findings may shed new light on the colour variations found in wild birds’ eggs.

“Within the UK you can have species like stone curlews, oystercatchers, Arctic skuas and nightjars that nest out in the open on the ground, essentially exposed to the element, including the sun and damaging UV,” Dr Portugal told BBC Nature.

These species’ eggs contain extra pigment which, according to the new research, helps control the amount of light entering through the shell and reaching the embryo.

Other eggs belonged to species that nest in holes, burrows and cavities, such as hoopoes, little owls and green woodpeckers.

The “immaculate” white shells prevalent in these nests allow “greater light transmission through the shell to assist embryonic development under low-light exposure,” said Dr Portugal.

The study also showed that birds with longer incubation periods had thicker shells with more pigment, to protect against harmful UV rays.

To examine how different eggshells control the amount of light allowed to shine through, Dr Portugal and an international team of researchers looked at eggs kept in the Natural History Museum in Tring, Hertfordshire.

Using a spectrophotometer, they shone a light through eggshells that had been cut in half and measured their “resistance”.

“One hundred percent light transmission means nothing in the way at all,” explained Dr Portugal. “Fifty percent would mean half the light is blocked by the shell.”

The team also extracted and examined the pigment present in each shell and measured their thickness.

Previous studies have shown an array of adaptations among birds’ eggs. These include many eggs displaying dark spots (or maculation) for camouflage, and pigment which can fight infection to protect embryos.

Dr Portugal added: “Eggshells are complex structures and far more sophisticated than many people would realise of appreciate.”

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Article source: http://www.bbc.co.uk/nature/28492239

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