Category Archives: Technology

How sleep makes the brain forget things – new research on mice

What a nuisance is a faulty memory. How many times have you forgotten where you parked the car? A few years ago, probably as a sign that my retirement was overdue, I spent literally half a day trying to find my car at a major New York airport. Fortunately, I am not alone. When people find out I am an expert on memory, the first thing they ask me is normally whether I can help them be less forgetful.

Indeed, excessive forgetting is a major problem, but “normal” forgetting is actually necessary. After all, it is more crucial to remember what is important right now than to remember everything. There’s no point in remembering the phone number of the house you lived in 10 years ago – that may in fact block your memory for your current phone number.

But exactly how the brain forgets unnecessary memories has long been unclear. Now a beautiful and rather exhaustive series of studies, just published in Science, offers a clue.

Research does indeed show that, in order to remember what is important, we need to forget what isn’t important. This can happen at two levels in the brain, a “cleaning” of irrelevant information as we retain and consolidate our memories, and a “blocking” of irrelevant information when we try to retrieve a memory. The positive effect on memory of blocking irrelevant information has been known since the 1950s.

The new study, which was carried out in mice, seems to finally reveal the secret mechanisms of forgetting during retention of memory. The authors claim that forgetting is due to the activation of specific “melatonin-concentrating hormone (MCH) neurons” located in the brain’s hypothalamus, which is involved in releasing hormones. We know that melatonin affects sleep – and MCH neurons are indeed involved in the shift between the two main sleep cycles: NREM to REM (REM sleep commonly associated with dreaming).

The authors demonstrate that forgetting happens only during retention (not when we encode or retrieve memories), and that sleep is the period of the day when MCH neurons clean the memory of all the irrelevant clutter. They obtained the results by injecting chemicals into the brain of mice in order to inhibit these very neurons. Amazingly, the mice performed better on two specific memory tasks as a result – recognising new objects and a fear conditioning test (this involves making association between stimuli and their adverse consequences).

What’s more, when the researchers completely removed these neurons from the brain, the mice’s memory also improved, over the long term. On the other hand, a boosted activity of these neurons instead hindered the mice’s memory performance. The researchers therefore argue that the neuronal process may one day be used to treat memory problems.

Read more: Why do you feel like you’re falling when you go to sleep?

This finding, if true and confirmed by other studies, represents a major breakthrough in understanding a fundamental memory mechanism. The methodology is rigorous and results convincing. There are some caveats though. How can we be absolutely sure that these neurons are involved in cleaning out irrelevant information in particular, rather than just impairing memory performance?

It seems that MCH neurons, when activated, just impair memory – and not necessarily with a good effect. This is important: the results do not say much about the positive role of forgetting during retention. In addition, whose memory are we talking about here? Mice memory – and necessarily so, given the highly invasive nature of most of the reported experiments. While animal models are indispensable for memory studies, it is too early to extend these findings to human memory.

For example, in humans the role of sleep in memory is still unclear. Also, forgetting occurs during retrieval of memories too and that is not explained by this new research.

Nevertheless, the new study does show for the first time that MCH neurons are strongly involved in making memory worse. That said, while we are on an exciting track thanks to this research, it is highly unlikely that we can improve human memory for a parked car by simply inhibiting a few neurons.

Giuliana Mazzoni received funding from Wellcome, Leverhulme, ESRC, SSHRC (Canada), Portuguese Science Foundation, British Academy.

Source: The Conversation: Technology http://theconversation.com/how-sleep-makes-the-brain-forget-things-new-research-on-mice-123636

Sail GP: how do supercharged racing yachts go so fast? An engineer explains

Sailing used to be considered as a rather sedate pastime. But in the past few years, the world of yacht racing has been revolutionised by the arrival of hydrofoil-supported catamarans, known as “foilers”. These vessels, more akin to high-performance aircraft than yachts, combine the laws of aerodynamics and hydrodynamics to create vessels capable of speeds of up to 50 knots, which is far faster than the wind propelling them.

An F50 catamaran preparing for the Sail GP series recently even broke this barrier, reaching an incredible speed of 50.22 knots (57.8mph) purely powered by the wind. This was achieved in a wind of just 19.3 knots (22.2mph). F50s are 15-metre-long, 8.8-metre-wide hydrofoil catamarans propelled by rigid sails and capable of such astounding speeds that Sail GP has been called the “Formula One of sailing”. How are these yachts able to go so fast? The answer lies in some simple fluid dynamics.

As a vessel’s hull moves through the water, there are two primary physical mechanisms that create drag and slow the vessel down. To build a faster boat you have to find ways to overcome the drag force.

The first mechanism is friction. As the water flows past the hull, a microscopic layer of water is effectively attached to the hull and is pulled along with the yacht. A second layer of water then attaches to the first layer, and the sliding or shearing between them creates friction.

On the outside of this is a third layer, which slides over the inner layers creating more friction, and so on. Together, these layers are known as the boundary layer – and it’s the shearing of the boundary layer’s molecules against each other that creates frictional drag.

A yacht also makes waves as it pushes the water around and under the hull from the bow (front) to the stern (back) of the boat. The waves form two distinctive patterns around the yacht (one at each end), known as Kelvin Wave patterns.

These waves, which move at the same speed as the yacht, are very energetic. This creates drag on the boat known as the wave-making drag, which is responsible for around 90% of the total drag. As the yacht accelerates to faster speeds (close to the “hull speed”, explained later), these waves get higher and longer.

These two effects combine to produce a phenomenon known as “hull speed”, which is the fastest the boat can travel – and in conventional single-hull yachts it is very slow. A single-hull yacht of the same size as the F50 has a hull speed of around 12 mph.

Hydrofoils

However, it’s possible to reduce both the frictional and wave-making drag and overcome this hull-speed limit by building a yacht with hydrofoils. Hydrofoils are small, underwater wings. These act in the same way as an aircraft wing, creating a lift force which acts against gravity, lifting our yacht upwards so that the hull is clear of the water.

While an aircraft’s wings are very large, the high density of water compared to air means that we only need very small hydrofoils to produce a lot of the important lift force. A hydrofoil just the size of three A3 sheets of paper, when moving at just 10 mph, can produce enough lift to pick up a large person.

This significantly reduces the surface area and the volume of the boat that is underwater, which cuts the frictional drag and the wave-making drag, respectively. The combined effect is a reduction in the overall drag to a fraction of its original amount, so that the yacht is capable of sailing much faster than it could without hydrofoils.

The other innovation that helps boost the speed of racing yachts is the use of rigid sails. The power available from traditional sails to drive the boat forward is relatively small, limited by the fact that the sail’s forces have to act in equilibrium with a range of other forces, and that fabric sails do not make an ideal shape for creating power. Rigid sails, which are very similar in design to an aircraft wing, form a much more efficient shape than traditional sails, effectively giving the yacht a larger engine and more power.

As the yacht accelerates from the driving force of these sails, it experiences what is known as “apparent wind”. Imagine a completely calm day, with no wind. As you walk, you experience a breeze in your face at the same speed that you are walking. If there was a wind blowing too, you would feel a mixture of the real (or “true” wind) and the breeze you have generated.

The two together form the apparent wind, which can be faster than the true wind. If there is enough true wind combined with this apparent wind, then significant force and power can be generated from the sail to propel the yacht, so it can easily sail faster than the wind speed itself.

The combined effect of reducing the drag and increasing the driving power results in a yacht that is far faster than those of even a few years ago. But all of this would not be possible without one further advance: materials. In order to be able to “fly”, the yacht must have a low mass, and the hydrofoil itself must be very strong. To achieve the required mass, strength and rigidity using traditional boat-building materials such as wood or aluminium would be very difficult.

This is where modern advanced composite materials such as carbon fibre come in. Production techniques optimising weight, rigidity and strength allow the production of structures that are strong and light enough to produce incredible yachts like the F50.

The engineers who design these high-performance boats (known as naval architects) are always looking to use new materials and science to get an optimum design. In theory, the F50 should be able to go even faster.

Jonathan Ridley does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Source: The Conversation: Technology http://theconversation.com/sail-gp-how-do-supercharged-racing-yachts-go-so-fast-an-engineer-explains-121902

How we discovered that an asteroid collision in space 466m years ago boosted life on Earth

Something mysterious happened nearly half a billion years ago that triggered one of the most important changes in the history of life on Earth. Suddenly, there was an explosion of species, with the biodiversity of invertebrate animals increasing from a very low level to something similar to what we see today. The most popular explanation for this “Great Ordovician Biodiversification Event” is that it was a result of an uncomfortably hot Earth cooling and eventually heading into an ice age.

But what actually triggered the change in temperature? In our new paper, published in Science Advances, we show that its onset coincided exactly with the largest documented asteroid breakup in the asteroid belt during the past two billion years, caused by a collision with another asteroid or a comet. Even today, almost a third of all meteorites falling on Earth originate from the breakup of this 150 kilometre-wide asteroid between Jupiter and Mars.

Following this event, enormous amounts of dust would have spread through the solar system. The blocking effect of this dust could have partly stopped sunlight from reaching the Earth – leading to cooler temperatures. We know that this involved the climate changing from being more or less homogeneous to becoming divided into climate zones – from Arctic conditions at the poles to tropical conditions at the equator. The high diversity among invertebrates, including green algae, primitive fish, cephalopods and corals, came as an adaptation to the new climate.

Swedish sea floor

Our evidence comes from detailed studies of sea floor sediments of Ordovician age (485m-443m years ago) exposed at Kinnekulle in southern Sweden and Lynna River near St. Petersburg in Russia. In a quarry at Kinnekulle, we found more than 130 “fossil meteorites” – rocks that fell on Earth in the ancient past, which became embedded in sea floor sediments and were preserved just like animal fossils.

All but one of these fossil meteorites, which are up to 20cm in diameter, have the same composition – they are all debris from the same collision. Indeed, they were made up of the same type of material as the large asteroid that broke up in the asteroid belt at the time. The other meteorite probably originates from the smaller body that hit the large asteroid.

We know that the asteroid collision took place 466m years ago. This can be dated by looking at isotopes (variants of chemical elements with a different number of neutrons in the nucleus) in recently fallen meteorites from the Ordovician asteroid breakup. The fossil meteorites in the quarry must therefore represent the material that was transported to Earth immediately after the breakup. And given the large number of meteorites that we found on the sea floor, we can estimate that the flux of meteorites to Earth must have been orders of magnitude higher back then than it is today.

But how do we know that this bombardment created a huge amount of dust that lowered the temperature? We also studied the distribution of very fine-grained, micrometre-sized dust in the sedimentary strata. We could determine that it had an extraterrestrial origin by detecting helium and other substances incorporated in the sediments that could only be explained by the solar wind having bombarded the dust, enriching it with those elements on its way to Earth.

Our results clearly show that enormous amounts of fine-grained dust reached Earth shortly after the breakup. And the geological record shows that shortly after the dust arrived, the sea level fell dramatically worldwide – the beginning of the ice age. That was because the sea water was transferred to the high latitudes, where large ice sheets formed.

The result was completely unexpected – we have during the last 25 years leaned against very different hypotheses in terms of understanding what happened during this period. For example, while we suspected that the diversification event was somehow linked to the asteroid breakup, we believed that the many small asteroids that also reached Earth from the breakup, rather than the dust, had something to do with the changes. It wasn’t until we got the last helium measurements that everything fell into place.

Lessons for climate research

Global warming continues as a consequence of carbon dioxide emissions, and the temperature rise is greatest at high latitudes. According to the Intergovernmental Panel on Climate Change, we are approaching a situation that is reminiscent of the conditions that prevailed prior to the asteroid collision 466m years ago. Clearly, continuing on that route is not going to be good for biodiversity.

In the last decade or so, researchers have discussed different artificial methods to cool the Earth in case of a major climate catastrophe. One solution would be to place asteroids, much like satellites, in orbits around Earth in such a way that they continuously liberate fine dust and hence partly block the warming sunlight.

Our results show for the first time that such dust at times has cooled Earth dramatically, giving hopes that it could be a viable artificial solution. Our studies can give a more detailed, empirical-based understanding of how this works that can be used to create and evaluate computer models of such events.

But for the foreseeable future, there is no other way to tackle climate change than to reduce our carbon emissions. Ultimately, that is the only way to preserve the spectacular boost in the diversity of life that happened all those 466m years ago.

Birger Schmitz received funding for this study from the European Research Council (Advanced Grant)

Source: The Conversation: Technology http://theconversation.com/how-we-discovered-that-an-asteroid-collision-in-space-466m-years-ago-boosted-life-on-earth-123639

#ShowYourStripes: how climate data became a cultural icon

It seems that people are finally waking up to the threat of climate change. The most poignant sign of this for me was seeing an infographic I created adorning the main music stage at Reading Festival 2019.

While the majority of those in the crowd may not have grasped its true meaning, or been in the frame of mind to understand it, it was a significant moment. A popular rock band publicly endorsed climate research and literally put it centre stage.

The climate stripes illustrate the global average temperature for every year since 1850 in the form of a coloured stripe. Shades of blue represent cooler years and red, warmer years. The overall effect is a striking trend towards hotter temperatures in recent decades, as a result of human-caused climate change.

The climate stripes follow other visualisations of climate data that I’ve created in recent years, including an animation depicting global temperature rise data as an ever-expanding spiral. This was used in the opening ceremony of the Rio Olympics in 2016 – more public recognition of science where you’d perhaps not expect it.

These graphics are simple and bright, but they’re based on solid science and carry a serious message. They translate complex data into an easily accessible format that transcends language and needs almost no context to explain it. The climate stripes have already been used on posters, on placards in the youth climate strikes and on banners and t-shirts around the world.

Helping science to make this leap from the lab to social media is crucial to changing mindsets. My research has often focused on communicating the impacts of climate change to new audiences. The more people that see and understand this huge problem, the better chance we have of solving it.

Earlier in 2019 we created a website that allows people to download climate stripes for around 200 countries and individual US states. This allowed people to share stripes which charted the recent climate history of their own corner of the world. TV weather forecasters around the world joined the campaign and used the stripes to talk about climate change in their regular broadcasts.

After a million downloads in the first week, dozens of examples appeared online of people wearing the stripes on ties and scarves, or even printing them on their Tesla. A town in Germany even printed them on a tram.

Explaining climate science to the public can be tricky. The scientific consensus is that the world is warming, but each region of the world is warming at a very different rate. Most parts of the UK are about 1℃ warmer than they were a century ago, while parts of the Arctic are almost 3℃ warmer. The climate stripes can communicate this nuance almost instantly.

If we want climate action to become the demand of a mass movement then we can’t expect discussions to be restricted to po-faced conversations between scientists and politicians. As grave a matter as it is, it needs to become a conversation we have everywhere, whether it be over the fence to our neighbours, on television soaps or while dancing at festivals. These simple graphics have helped start those conversations.

Climate change is inevitably reported in a negative way, but we can be positive about the story we tell. Infiltrating popular culture is one way scientists can help trigger a step change in attitudes that will lead to mass action. We face some difficult choices, but we still have time to make changes that will create a hopeful future.

This article is part of The Covering Climate Now series
This is a concerted effort among news organisations to put the climate crisis at the forefront of our coverage. This article is published under a Creative Commons license and can be reproduced for free – just hit the “Republish this article” button on the page to copy the full HTML coding. The Conversation also runs Imagine, a newsletter in which academics explore how the world can rise to the challenge of climate change. Sign up here.

Ed Hawkins receives funding from the UK Natural Environment Research Council.

Source: The Conversation: Technology http://theconversation.com/showyourstripes-how-climate-data-became-a-cultural-icon-123457

Groupthink – is it a valid argument against climate science?

When the Australian federal environment minister, Sussan Ley, went snorkelling on the Great Barrier Reef in August, she told waiting reporters on the shore that she’d seen “amazing wildlife, fish, turtles, clams … a reef teeming with life”.

Such an upbeat assessment seems at odds with the Scientific Consensus Statement, released by the Queensland government in 2017, which said “key Great Barrier Reef ecosystems continue to be in poor condition”.

Of course, no one doubts what Ley saw – but the contrast between what we can directly experience and what scientists tell us is the bigger picture is brought into sharp relief when these perspectives are put side by side. If we are to go beyond our own experience and not just rely on anecdotes (as some media do repeatedly), then we have to take a leap of faith and trust the experts.

But climate scientists still sometimes face an uphill battle in building that trust. Why?

One of the charges made against climate scientists who are trying to get their message across is that the much-vaunted 97% consensus on the existence of human-made global warming arises only because dissenting voices are not allowed a seat at the table. And, as some people ask – what about the other 3%?

Taken to an extreme, such critiques are tantamount to accusing the climate community of “groupthink” – a term coined in 1972 by American psychologist Irving Janis, which has become a catch-all label for defective decision-making that can arise from groups with dysfunctional dynamics.

Conditions for groupthink

For groupthink to develop, Janis argued, several existing conditions needed to be in place. These include group cohesiveness, insularity, and a lack of procedures for the search and appraisal of information. If a group is afflicted by these conditions then there are several tell-tale signs: stereotyped views of rivals and enemies; self-censorship of doubts or counterarguments to create an illusion of unanimity; and direct pressure on any members that express strong arguments against any of the group stereotypes.

So does the accusation of groupthink stack up when it comes to climate science? No, not at all. Science thrives on debate. It lives by argument and counter-argument. It handsomely rewards breakthroughs that upset the status quo (Albert Einstein comes to mind). If someone could publish a paper tomorrow that provided a rigorous and scientifically defensible alternative interpretation of human-made global warming they would become a (science) superstar.

The methods of science are not perfect, but they directly counter one of the key components of groupthink. Far from having a “lack of procedures for search and appraisal of information”, the scientific method is exactly this: a process of observing (searching), making predictions, testing them and publishing results in peer-reviewed journals (the appraisal).

For example, Queensland’s Scientific Consensus Statement relied on more than 1,600 peer-reviewed papers and reports produced by many hundreds of independent authors from all over the world. In other words, a bit more definitive than the impression garnered from a quick dip on the reef in a specific place.

And what about that 3% you might ask? Agreement with the scientific consensus is strongly correlated with climate-science expertise. So one reaction to the 3% is that they are less well-informed than those scientists who publish regularly in climate science. This suggests even less of a reason to let the tiny minority undermine trust in the vast majority.

Perception and portrayal

From the “inside” looking out, it seems clear to scientists that groupthink has not taken over, and there is no danger that it will. Nevertheless, the public perception and (some) media portrayals of the climate scientists as being unwilling to listen to dissenters, combined with an unassailable belief in the correctness of their position, still persists. How do scientists overcome this gap in trust?

One solution might simply be for the public to realise that science is never black and white. As scientists are at pains to point out, there is very rarely incontrovertible evidence in any field, and science can only provide a current summary of the accumulated knowledge that has withstood the scrutiny of the scientific method. In other words, science doesn’t claim to be infallible, but it is the best we can do using rigorous techniques of inquiry and testing.

Some research suggests that people who think of science as debate between alternative positions are more persuaded by messages that communicate high uncertainty than those who see science as the search for absolute truth. This is important because it suggests a way to overcome the ever-present problem of embracing the uncertainty that is inherent in any prediction, without leading people to conclude that nobody really knows anything and so we should not worry. Uncertainty is inevitable.

Read more: Uncertainty isn’t cause for climate complacency – quite the opposite

Another solution is for us all to think critically about the source of the information. If a climate scientist refuses to debate someone who is challenging their position, is this evidence for insularity and ignoring dissent? Only if those challengers are credible rather than mouthpieces for vested interests, as is often the case.

Scientists have to walk a fine line between communicating the science clearly and getting embroiled in advocacy, or divisive rhetoric. Indeed, some have argued that misleading arguments – such as there being a hiatus in global warming – can “seep” into scientific discussion (and research) partly through the pressure to engage in “faux” debate.

As members of the public it might be effortful to engage our cognitive resources and do a level of fact-checking or trust-assessment, but it is crucial. To disengage now could have disastrous consequences for us all.

This article is part of The Covering Climate Now series
This is a concerted effort among news organisations to put the climate crisis at the forefront of our coverage. This article is published under a Creative Commons license and can be reproduced for free – just hit the “Republish this article” button on the page to copy the full HTML coding. The Conversation also runs Imagine, a newsletter in which academics explore how the world can rise to the challenge of climate change. Sign up here.

Ben Newell receives funding from the Australian Research Council

Source: The Conversation: Technology http://theconversation.com/groupthink-is-it-a-valid-argument-against-climate-science-123050

New technology isn’t the cause of inequality – it’s the solution

Technology has been blamed for a lot recently. Automation and artificial intelligence have supposedly led to substantial job losses, reduced bargaining power for workers and increased discrimination. It is even blamed for growing income and wealth inequality and, as a result, the presidency of Donald Trump, Brexit, the rise of far-right populism in Europe and the spectre of climate change.

In response, calls are being made for global oversight and regulation of technology and there are attempts to slow down its spread through protectionist trade policies and political lobbying.

But perhaps we should be careful about so readily blaming technological innovation for these social problems. In fact, our recent research into the causes of rising income inequality in Germany suggests a lack of innovation and entrepreneurship is actually at the root of the problem.

We shouldn’t be trying to obstruct technological innovation and diffusion. Rather, we should face up to the challenge of bringing back to Western economies the entrepreneurship, innovativeness and business dynamism that characterised the years after World War II, when growth was also more inclusive.

Germany is a particularly useful case to study. In recent decades, inequality has risen fast, and to unprecedented levels since unification. But unlike in the US, for example, there has been little financialisation of the economy and no significant outsourcing of jobs due to globalisation. Whereas the US runs a huge trade deficit, Germany runs a large trade surplus. Importantly, evidence shows automation has created more jobs in Germany than it has destroyed. So why is inequality rising so rapidly in the EU’s largest economy?

We argue that this is because consumers, investors and innovators in Germany are effectively “on strike”. Consumption by households, government and corporations could be much higher in Germany, but they are all saving massively. Public and corporate gross fixed investment spending are dwindling. As a result, the domestic market, which is also aging rapidly, is not as attractive a place for entrepreneurs and corporations to stimulate innovation.

Without enough investment, labour productivity growth has significantly declined over the past three decades, falling from 2.5% in 1992 to 0.3% in 2013, eight times slower. This has been used to justify a progressive reduction in real wages, union bargaining power and social security benefits to maintain competitiveness. And this is one of the fundamental mechanisms driving German inequality.

This conclusion may seem at odds with common perceptions of Germany as a successful, technology-driven developed economy. Despite falling overall investment, the country certainly appears to be spending massively on stimulating innovation. German spending on research and development has increased by around 50% in real terms between 2000 and 2016 and is now approaching an excellent 3% of GDP.

The question is: what is all this money buying? Why are productivity and economic growth not accelerating? Put simply, Germany’s innovation is less effective and less likely to be commercialised than in the past. For example, the ratio between the number of patents granted and the number actually applied for has been in long-term decline since the late 1980s. The relative quality of patents as measured by citations has also declined. There are only four German firms among the world’s top 30 innovative corporations in high-tech areas such as 3D-printing, nanotechnology, and robotics.

And while total innovation spending is high, it’s concentrated in larger companies. Most small and medium sized firms in Germany are investing nothing or very little in innovation.

The decline in the impact of innovation also reflects the fact that entrepreneurship has been stagnating in Germany. The Mannheim Enterprise Panel index of start-up activity (a good measure of entrepreneurial dynamics) fell from 120 to 60 between 1990 and 2013, a 50% decline. This is partly because existing companies have adopted conservative or defensive strategies to keep out new entrants to the market rather than use innovation to compete with them.

To reduce inequality, Germany needs innovation that will increase labour productivity. The country needs more firms, particularly small and medium ones, to develop and commercialise new technology and adopt a more robust spirit of entrepreneurship.

Achieving this will require critical changes in the innovation system, in particular to stimulate competition, invest more in critical public infrastructure, and improve internet connectivity and speed. Urgent measures are also needed to refocus the country’s vital auto industry away from being locked into out-of-date technologies.

Most importantly however the country needs to adopt measures that will spur on the government, consumers and companies to spend more. This will be good for innovation by creating the demand for new products and services. And one way of funding this would be to more effectively tax big corporations.

The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

Source: The Conversation: Technology http://theconversation.com/new-technology-isnt-the-cause-of-inequality-its-the-solution-123476

What neuroscientists are learning about our brains in space by launching themselves into zero gravity flight

More than 500 people have travelled into space to date and, while we know a little about how life without gravity affects our physical health, we know almost nothing about how it affects our minds.

So, my colleagues and I have been launching ourselves, rigs of equipment and our participants into “zero gravity flight” to perform experiments. It’s a thrilling – and sometimes extremely nauseating – life, but its opening new windows into how we think and perceive differently in space. This is no doubt important if we want to colonise outer space.

Weightlessness is a key component of the spaceflight experience. Since the first space missions, however, it’s been clear weightlessness causes a variety of health issues – particularly degrading muscle mass, causing disorientation and blurred vision.

This should not be surprising as all living organisms have evolved under the constant “1g” of gravitational force. But we also need to find out how weightlessness influences our perception and behaviour. Without going to the International Space Station (ISS), the best way to do this is on a zero gravity flight. During these flights, a refitted Airbus A310 aircraft follows the trajectory of a parabola. This means it alternates between rises and descents, at a 45° angle of inclination.

Each parabola starts with a “pull-up” acceleration phase in which the gravitational load is double Earth gravity (hypergravity, 2g). This lasts about 20 seconds. The pilots then let the aircraft drop into “free-fall”. For the next 20 seconds, everything and everybody on board the aircraft is exposed to weightlessness (microgravity, 0g). Once the craft reaches a particular angle of tilt, the pilots perform a “pull-out” acceleration, in which gravity is again double. This is repeated up to 30 times and the entire flight lasts around three hours.

Bumpy ride

Doing science on these roller coaster parabolic flight manoeuvres is very challenging. There are severe constraints on time. Whatever the experiment requires, it has to be performed in about 20 seconds.

Because several experiments must go up together, space is also tight. So, forget the comfort of a lab. Instead, visualise a 1.5 x 1.5 metres allocated habitat – in which your equipment, experimenters and participants all need to fit. You can’t risk mistakes so each experimental step, even each movement, needs to be perfectly planned. These movements must also be perfectly synchronised with drops and lifts of the plane. Like a dance, we choreograph and rehearse in the days before lift off.

To me, the real challenge of doing science on a parabolic flight is dealing with motion sickness. It is not by chance that parabolic flights have earned the nickname “Vomit Comet”.

On Earth, we have a system in our inner ear that tells us the direction and amount of gravitational pull, relative to the position of our heads (the vestibular system). In weighlessness, the 1g pull we have experienced our whole lives disappears. The vestibular system can no longer function as it should, often leading to space motion sickness (which mimics a severe car motion sickness), nausea and vomiting.

The science

Why embark on such an adventure? This is the ultimate frontier of understanding how the brain can adapt to new environments and demands in microgravity. On a practical level, understanding the brain’s response to weightlessness is necessary to ensure the success and safety of future manned space missions.

We have also been investigating the effect of gravity on the perception of our own body weight. So far research has looked largely at how society and culture affects body weight perception. And we know that body satisfaction, body image and risk for eating disorders play a role.

However, the true weight of our body – like any other object on Earth – depends on the pull of gravity. Because of this, we predicted the way we perceive our own body weight would also be dependent on the pull of gravity. We asked participants to estimate the weight of their hand and their head both in normal terrestrial gravity and during exposure to microgravity and hypergravity on a European Space Agency parabolic flight campaign at the German Aerospace Center (DLR Cologne).

We showed that alterations of gravity produced rapid changes in perceived weight: there was an increase in perceived weight during hypergravity, and a decrease during microgravity.

While this might seem obvious – our actual weight changes accordingly – it’s important, because perceptions of our body weight, shape and position are critical to successful movement and interactions with our surroundings. The fact that we are researching such basic things just goes to show how little we actually know about it. Imagine, for example, that you are an astronaut operating levers to control a robotic space arm. Misunderstanding the weight of your own arm could cause you to pull too hard, swinging the arm into the side of your spacecraft.

Ultimately, we aim to understand how the human brain builds a representation of gravity and uses it in cognition to guide behaviour. We have previously shown that gravity may influence how we make decisions, with a lack of it potentially making us more risk-averse. This sort of research has never been more timely and it yields advantages for enhancing human performance in upcoming space exploration.

We may have underestimated the effects of gravity on our cognition so far because gravity is so stable on Earth. It is arguably the most persistent sensory signal in the brain. I predict the next couple of decades will reveal a lot about how gravity has been affecting the way we think, feel and act – without us even noticing.

In the meantime, I am enjoying the ride – weightlessness is the best experience I have ever had. The pilots announce “3, 2, 1, INJECT”, and there you are floating. There are no bodily constraints, just effortless movements and unpredicted movements of your limbs that lead to euphoria, excitement and enhanced awareness of your body. It is very hard to sum up experience – I can only say it’s a feeling of awe and freedom.

Elisa Raffaella Ferrè received funding from the European Space Agency (ESA), the European Low Gravity Association Research (ELGRA) and the UK Royal Society to conduct this research.

Source: The Conversation: Technology http://theconversation.com/what-neuroscientists-are-learning-about-our-brains-in-space-by-launching-themselves-into-zero-gravity-flight-122359

Mass extinctions made life on Earth more diverse – and might again

In the past half-billion years, Earth has been hit again and again by mass extinctions, wiping out most species on the planet. And every time, life recovered and ultimately went on to increase in diversity.

Is life just incredibly resilient, or is something else going on? Could mass extinctions actually help life diversify and succeed – and if so, how? Given that we’re currently facing another extinction event, there’s extra urgency in trying to work out how mass extinctions affect diversity.

Mass extinction is probably the most striking pattern in the fossil record. Vast numbers of species – even entire families – disappear rapidly, simultaneously, around the world. Extinction on this scale usually requires some kind of global environmental catastrophe, so severe and so rapid that species can’t evolve, and instead disappear.

Massive volcanic eruptions drove the extinctions at the end of the Devonian, Permian and Triassic periods. Global cooling and intense glaciation drove the Ordivician-Silurian extinctions. An asteroid caused the end-Cretaceous extinction of the dinosaurs. These “Big Five” extinctions get the most attention because, well, they’re the biggest. But lots of lesser yet still civilisation-threatening events occurred as well, like the pulse of extinction before the end-Permian event.

These events were indescribably destructive. The Chicxulub asteroid impact that ended the Cretaceous period shut down photosynthesis for years and caused decades of global cooling. Anything that couldn’t shelter from the cold, or find food in the darkness – which was most species – perished. Perhaps 90% of all species disappeared in just a few years.

But life bounced back and the recovery was rapid. 90% of mammal species were eliminated by the asteroid, but they recovered and then some within 300,000 years, going on to evolve into horses, whales, bats and our primate ancestors. Birds and fish experienced similarly rapid recovery and radiation. And many other organisms – snakes, tuna and swordfish, butterflies and ants, grasses, orchids and asters – evolved or diversified at the same time.

This pattern of recovery and diversification happened after every mass extinction. The end-Permian extinction saw mammal-like species take a hit, but reptiles flourished afterward. After the reptiles suffered during the end-Triassic event, the surviving dinosaurs took over the planet and diversified. Although a mass extinction ended the dinosaurs, they only evolved in the first place because of mass extinction.

Despite this chaos, life slowly diversified over the past 500m years. In fact, several things hint that extinction drives this increased diversity. For one, the most rapid periods of diversity increase occur immediately after mass extinctions. But perhaps more striking, recovery isn’t only driven by an increase in species numbers.

In a recovery, animals innovate – finding new ways of making a living. They exploit new habitats, new foods, new means of locomotion. For example, our fish-like forebears first crawled onto land after the end-Devonian extinction.

Evolutionary innovation

Extinction doesn’t only drive this process of speciation. It also drives evolutionary innovation. It’s not a coincidence that the biggest pulse of innovation in life’s history – the evolution of complex animals in the Cambrian Explosion – happened in the wake of the extinction of the Ediacaran animals that went before them.

Innovation may increase the number of species that can coexist because it allows species to move into new niches, instead of fighting over the old ones. Fish crawling onto land didn’t compete with fish in the seas. Bats hunting at night with sonar didn’t compete with birds that were active during the day. Innovation means evolution isn’t a zero-sum game. Species can diversify without driving others extinct. But why does extinction drive innovation?

Stable ecosystems may prevent innovation. A modern wolf is probably a far more dangerous predator than a velociraptor, but a tiny mammal couldn’t evolve into a wolf in the Cretaceous because there were velociraptors. Any experiments in carnivory would have ended badly, with the poorly adapted mammal competing with – or just eaten by – the already well-adapted Velociraptor.

But, in the lulls after an extinction, evolution may be able to experiment with designs that are initially poorly adapted, but with long-term potential. With the show’s stars gone, the evolutionary understudies get their chance to prove themselves.

The extinction of Velociraptor gave mammals the freedom to experiment with new niches. Initially, they were poorly equipped for a predatory lifestyle, but without dinosaurs competing with or eating them, they didn’t need to be terribly good to survive. They only needed to be as good as the other things around at the time. So they flourished in an ecological vacuum, ultimately evolving into big, fast, intelligent pack hunters.

Creative destruction

Life isn’t just resilient, it thrives on adversity. Life will even recover from the current wave of human-induced extinctions. If we disappeared tomorrow, then species would evolve to replace woolly mammoths, dodo birds and the passenger pigeon, and life would likely become even more diverse than before. That’s not to justify complacency. It won’t happen in our lifetime, or even the lifetime of our species, but millions of years from now.

This idea that extinction drives innovation may even apply to human history. The extinction of ice-age megafauna must have decimated hunter-gatherer bands, but it also may have given farming a chance to develop. The Black Death produced untold human suffering, but the shakeup of political and economic systems may have led to the Renaissance.

Economists talk about creative destruction, the idea that creating a new order means destroying the old one. But evolution suggests there’s another kind of creative destruction, where the destruction of the old system creates a vacuum and actually drives the creation of something new and often better. When things are at their worst is precisely when the opportunity is the greatest.

Nick Longrich does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Source: The Conversation: Technology http://theconversation.com/mass-extinctions-made-life-on-earth-more-diverse-and-might-again-122350

Curiosity: we’re studying the brain to help you harness it

They say curiosity killed the cat for a reason. Being curious has many advantages, but it is also associated with risk taking. But what is curiosity exactly? Is it really just one personality trait that you can have more or less of? Or do people have different “curiosity types” – being naturally more curious about people, sensations or knowledge?

We’re looking at people’s brains to find out. And we are hoping our research can help unlock the benefits of curiosity for learning and education.

We already know a bit about the neuroscience of curiosity. Have you ever desperately struggled to study a topic that just does not spark your curiosity, and then found you remember nothing when you try to recall it later? This makes total sense, as research demonstrates that being in a state of high curiosity enhances our memory for interesting information.

It might seem obvious that if you are curious about something, you pay more attention to it, making it easier to remember later – but the effects of curiosity on memory are more complex than this. Being in a highly curious state also improves our memory for information unrelated to what made us curious in the first place.

The link with learning can actually be seen in the brain. Curiosity leads to activation of several areas of the brain, particularly the regions known as the substantia nigra, ventral tegmental area and the hippocampus. And connectivity between these same regions are associated with learning.

Fear and curiosity

Some early philosophers speculated that curiosity evolved as an instinct that helps us adapt to new environments by driving us to explore them. However, this seems to conflict with other theories suggesting we fear new environments because of the potential danger they may hold.

It seems curiosity and fear can be provoked by the same situations, with curiosity sometimes overriding our fear of exploring new things. For some, fear may form part of the excitement of curiosity. We know that brain systems linked with wanting to receive external rewards (like money or food) are activated when we are curious. This indicates that curiosity is a sort of craving of more information.

But curiosity has also been associated with characteristics that reflect risk taking, stress tolerance and thrill seeking. This is how curiosity got its bad wrap as a mortal danger to felines.

Personality type

We all know some people tend to be more curious than others. Supporting this, research shows some individuals experience curiosity more frequently or intensely than others. But is curiosity as a personality trait just a level of degree – more versus less?

Instead, it may be that we are all similarly curious, but that personality drives us to be more curious about specific things or situations. These are known as curiosity “types”.

Epistemic curiosity has been widely researched. This describes a person’s desire to acquire new information – such as facts, concepts or ideas – and bridge any gaps in their knowledge.

Social curiosity, on the other hand, describes an individual’s fascination and fixation on how other people think, act and feel – which subsequently affects how they navigate the interpersonal world. People who show perceptual curiosity, on the other hand, try to maximise the sensory information they take in – like your friend who can’t stop looking around at anything and everything.

To help us understand if curiosity is one or many traits, our research looks at whether these different curiosity types are supported by different brain mechanisms. We also want to know whether being struck by a moment of curiosity sparks activity in the same brain areas that explain how curious a person is generally.

So far, our preliminary results suggest we may have identified an important area relating to epistemic curiosity – but not other types. Known as the fornix, this is a critical brain structure that connects the hippocampus (an important brain hub for memory) and brain areas related to learning, information seeking and exploration.

These findings make total sense. The more curious we are about information in general, the better the connections between brain networks associated with learning, information seeking and motivation.

Harnessing curiosity

This research can help us to understand how we can better harness curiosity in the real world, such as in work and educational settings.

As the fornix is related to enhanced learning, this suggests we should strive to create learning environments that foster exploration of ideas and information searching. This will help boost curiosity, with the fornix helping us remember what we learn better. Gaining knowledge in this way would be very different from just delivering a set teaching material.

There could be important benefits. Current research has shown that the effects of curiosity on learning are even stronger for children from families with a low socioeconomic status.

In the next years, our research will map out how different types of curiosity are related to different brain areas and how this enhances learning for various types of information. We will then better understand how our individual curiosity helps us to learn certain things in ways that are unique for us.

But it is already clear that there is a lot to gain from valuing and fostering curiosity in children. And this is not only true for children. Continuously stimulating our curiosity could lead to a more prosperous and fulfilling life as adults too.

Ashvanti Valji receives funding from Cardiff University

Matthias Gruber receives funding from Wellcome and the Royal Society.

Source: The Conversation: Technology http://theconversation.com/curiosity-were-studying-the-brain-to-help-you-harness-it-122351

How fast is the universe really expanding? New measurements help tackle the mystery

Advances in astronomical observation over the past century have allowed scientists to construct a remarkably successful model of how the cosmos works. It makes sense – the better we can measure something, the more we learn. But when it comes to the question of how fast our universe is expanding, some new cosmological measurements are making us ever more confused.

Since the 1920s we’ve known that the universe is expanding – the more distant a galaxy is, the faster it is moving away from us. In fact, in the 1990s, the rate of expansion was found to be accelerating. The current expansion rate is described by something called “Hubble’s Constant” – a fundamental cosmological parameter.

Until recently, it seemed we were converging on an accepted value for Hubble’s Constant. But a mysterious discrepancy has emerged between values measured using different techniques. Now a new study, published in Science, presents a method that may help to solve the mystery.

The problem with precision

Hubble’s Constant can be estimated by combining measurements of the distances to other galaxies with the speed they are moving away from us. By the turn of the century, scientists agreed that the value was about 70 kilometres per second per megaparsec – one megaparsec is just over 3m light years. But in the last few years, new measurements have shown that this might not be a final answer.

If we estimate Hubble’s Constant using observations of the local, present-day universe, we get a value of 73. But we can also use observations of the afterglow of the Big Bang – the “cosmic microwave background” – to estimate Hubble’s Constant. But this “early” universe measurement gives a lower value of around 67.

Worryingly, both of the measurements are reported to be precise enough that there must be some sort of problem. Astronomers euphemistically refer to this as “tension” in the exact value of Hubble’s Constant.

If you’re the worrying kind, then the tension points to some unknown systematic problem with one or both of the measurements. If you’re the excitable kind, then the discrepancy might be a clue about some new physics that we didn’t know about before. Although it has been very successful so far, perhaps our cosmological model is wrong, or at least incomplete.

Distant versus local

To get to the bottom of the discrepancy, we need a better linking of the distance scale between the very local and very distant universe.

The new paper presents a neat approach to this challenge. Many estimates of the expansion rate rely on the accurate measurement of distances to objects. But this is really hard to do: we can’t just run a tape measure across the universe.

One common approach is to use “Type 1a” supernovas (exploding stars). These are incredibly bright, so we can see them at great distance. As we know how luminous they should be, we can calculate their distance by comparing their apparent brightness with their known luminosity.

To derive Hubble’s Constant from the supernova observations, they must be calibrated against an absolute distance scale because there is still a rather large uncertainty in their total brightness. Currently, these “anchors” are very nearby (and so very accurate) distance markers, such as Cepheid Variable stars, which brighten and dim periodically.

If we had absolute distance anchors further out in the cosmos, then the supernova distances could be calibrated more accurately over a wider cosmic range.

Far-flung anchors

The new work has dropped a couple of new anchors by exploiting a phenomenon called gravitational lensing. By looking at how light from a background source (like a galaxy) bends due to the gravity of a massive object in front of it, we can work out the properties of that foreground object.

The team has studied two galaxies that are lensing the light from two other background galaxies. The distortion is so strong that multiple images of each background galaxy are projected around the foreground deflectors (such as in the image above). The components of light making up each of those images will have travelled slightly different distances on their journey to Earth as the light bends around the foreground deflector. This causes a delay in the arrival time of light across the lensed image.

If the background source has a fairly constant brightness, we don’t notice that time delay. But when the background source itself varies in brightness, we can measure the difference in light arrival time. This work does exactly that.

The time delay across the lensed image is related to the mass of the foreground galaxy deflecting the light, and its physical size. So when we combine the measured time delay with the mass of the deflecting galaxy (which we know) we get an accurate measure of its physical size.

Like a penny held at arms length, we can then compare the apparent size of the galaxy to the physical size to determine the distance, because an object of fixed size will appear smaller when it is far away. The authors present absolute distances of 810 and 1230 megaparsecs for the two deflecting galaxies, with about a 10-20% margin of error.

Treating these measurements as absolute distance anchors, the authors go on to reanalyse the distance calibration of 740 supernovas from a well-established data set used to determine Hubble’s Constant. The answer they got was just over 82 kilometres per second per megaparsec.

This is quite high compared to the numbers mentioned above. But the key point is that with only two distance anchors the uncertainty in this value is still quite large. Importantly, though, it is statistically consistent with the value measured from the local universe. The uncertainty will be reduced by hunting for – and measuring – distances to other strongly lensed and time-varying galaxies. They are rare, but upcoming projects like the Large Synoptic Survey Telescope should be capable of detecting many such systems, raising hopes of reliable values.

The result provides another piece of the puzzle. But more work is needed: it still doesn’t explain why the value derived from the cosmic microwave background is so low. So the mystery remains, but hopefully not for too long.

James Geach receives funding from the Royal Society and the Science and Technology Facilities Council

Source: The Conversation: Technology http://theconversation.com/how-fast-is-the-universe-really-expanding-new-measurements-help-tackle-the-mystery-123338