星空体育频道

2013年7月3日星期三

Gamblers like noisy slot machines -- it reinforces the rewarding feeling after a win

July 2, 2013 — Gamblers like noisy slot machines -- it reinforces the rewarding feeling after a win.

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Winning sounds on slot machines make gambling more exciting, according to a new study by Mike Dixon and colleagues from the University of Waterloo in Canada. Moreover, their work shows that sounds also cause players to overestimate the number of times they won while playing on slot machines. The study is published online in Springer's Journal of Gambling Studies.

Sound has always been an integral part of the slot machine playing experience. Since the early 1900s, players have been rewarded with a ringing bell every time they have a winning combination. Today's slot machines average about 400 sound effects.

Modern slot machines allow players to wager on multiple lines. When they spin and lose, the machine goes quiet. When they spin and win more than their wager, they hear a celebratory song. Interestingly, when they spin and win back less than their wager (bet $1.00 and win back 20 cents) they still hear the celebratory songs despite the fact that overall they lost money on these spins. Dixon and colleagues sought to see if these celebratory sounds could hide the fact that players were losing money on these so-called 'losses disguised as wins.'

Dixon and team measured gamblers' physiological responses to various slot machine game outcomes -- wins, losses and losses disguised as wins -- with and without sound during play. During slot machine play, palms may sweat, which increases skin conductance -- a measure of arousal.

A total of 96 gamblers played two sessions on a slot machine simulator. In one session, both wins and 'losses disguised as wins' were accompanied by rolling sounds and celebratory winning jingles, as well as visual feedback. In a second session, the sounds were turned off and players only received visual feedback. The researchers measured the participants' skin conductance and heart rate responses to the various outcomes. At the end of play, the gamblers were asked which session they preferred and why. They also estimated how many spins they had won back more than they wagered.

Sound influenced the overall levels of arousal of players. Skin conductance responses were significantly greater in the session with sound than in the session without sound. Players also rated the noisy session as more arousing than the quiet session. The majority of players preferred the playing session where wins were accompanied by sounds, which suggests that not only do sounds make playing more exciting, players enjoy this extra level of excitement.

Sounds also contributed to players overestimating their number of wins. While this overestimation occurred both in the quiet and noisy sessions, it was significantly higher in the session with sound -- 24 percent versus 15 percent in the session without sound. The authors suggest that sounds may be an integral part of 'the disguise' in losses disguised as wins, causing players to think that they have won more often during a playtime session than they actually have.

The authors conclude: "Although sounds may have contributed to players' enjoyment of the game, sound may also lead to an overestimation of winning. Both of these effects may contribute to gambling problems, such as misbeliefs about the true chances of winning, and persistence that some players experience when playing slot machines."

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Cluster spacecraft detects elusive space wind

"After long scrutiny of the data, there it was, a slow but steady wind, releasing about 1 kg of plasma every second into the outer magnetosphere: this corresponds to almost 90 tonnes every day. It was definitely one of the nicest surprises I've ever had!" said Dandouras of the Research Institute in Astrophysics and Planetology in Toulouse, France.

The plasmasphere is a region filled with charged particles that takes up the inner part of Earth's magnetosphere, which is dominated by the planet's magnetic field.

To detect the wind, Dandouras analysed the properties of these charged particles, using information collected in the plasmasphere by ESA's Cluster spacecraft. Further, he developed a filtering technique to eliminate noise sources and to look for plasma motion along the radial direction, either directed at Earth or outer space.

As detailed in the new Annales Geophysicae study, the data showed a steady and persistent wind carrying about a kilo of the plasmasphere's material outwards each second at a speed of over 5,000 km/h. This plasma motion was present at all times, even when Earth's magnetic field was not being disturbed by energetic particles coming from the Sun.

Researchers predicted a space wind with these properties over 20 years ago: it is the result of an imbalance between the various forces that govern plasma motion. But direct detection eluded observation until now.

"The plasmaspheric wind is a weak phenomenon, requiring for its detection sensitive instrumentation and detailed measurements of the particles in the plasmasphere and the way they move," explains Dandouras, who is also the vice-president of the EGU Planetary and Solar System Sciences Division.

The wind contributes to the loss of material from Earth's top atmospheric layer and, at the same time, is a source of plasma for the outer magnetosphere above it. Dandouras explains: "The plasmaspheric wind is an important element in the mass budget of the plasmasphere, and has implications on how long it takes to refill this region after it is eroded following a disturbance of the planet's magnetic field. Due to the plasmaspheric wind, supplying plasma -- from the upper atmosphere below it -- to refill the plasmasphere is like pouring matter into a leaky container."

The plasmasphere, the most important plasma reservoir inside the magnetosphere, plays a crucial role in governing the dynamics of Earth's radiation belts. These present a radiation hazard to satellites and to astronauts travelling through them. The plasmasphere's material is also responsible for introducing a delay in the propagation of GPS signals passing through it.

"Understanding the various source and loss mechanisms of plasmaspheric material, and their dependence on the geomagnetic activity conditions, is thus essential for understanding the dynamics of the magnetosphere, and also for understanding the underlying physical mechanisms of some space weather phenomena," says Dandouras.

Michael Pinnock, Editor-in-Chief of Annales Geophysicae recognises the importance of the new result. "It is a very nice proof of the existence of the plasmaspheric wind. It's a significant step forward in validating the theory. Models of the plasmasphere, whether for research purposes or space weather applications (e.g. GPS signal propagation) should now take this phenomenon into account," he wrote in an email.

Similar winds could exist around other planets, providing a way for them to lose atmospheric material into space. Atmospheric escape plays a role in shaping a planet's atmosphere and, hence, its habitability.

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Protocells may have formed in a salty soup

July 2, 2013 — The first cell may have originated in a salty soup in which large biomolecules cluster spontaneously to form a protocell, chemists at Radboud University Nijmegen discovered.

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The research is published in the Proceedings of the National Academy of Sciences.

How did the first cell originate in evolution? It is a chicken or the egg causality dilemma: a cell doesn't function without a cell wall, but how does the cell wall form if there is no cell? Research by chemist Wilhelm Huck, professor at Radboud University Nijmegen, suggests that the cell came first.

In a solution containing the biomolecules that are normally locked in a cell (like DNA, RNA, enzymes, proteins) these large biomolecules clustered together spontaneously when the salt concentration was increased. This indicates that a cell wall is not a prerequisite for a cell-like structure .

Huck thinks the macro molecules in our cells evolved to do their work while packed closely together. By using tiny droplets, he explores how this works exactly. "When biomolecules are packed together, we expect reactions to proceed much faster. They perform their chemistry much more efficiently. In this study, we measure a fifty-fold increase in the DNA transcription rate."

A working cell is more than the sum of its parts. "A functioning cell must be entirely correct at once, in all its complexity," said Huck. "We are now closer to building a synthetic cell than anyone ever before us."

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Teens' self-consciousness linked with specific brain, physiological responses

July 2, 2013 — Teenagers are famously self-conscious, acutely aware and concerned about what their peers think of them. A new study reveals that this self-consciousness is linked with specific physiological and brain responses that seem to emerge and peak in adolescence.

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"Our study identifies adolescence as a unique period of the lifespan in which self-conscious emotion, physiological reactivity, and activity in specific brain areas converge and peak in response to being evaluated by others," says psychological scientist and lead researcher Leah Somerville of Harvard University.

The findings, published in Psychological Science, a journal of the Association for Psychological Science, suggest that teens' sensitivity to social evaluation might be explained by shifts in physiological and brain function during adolescence, in addition to the numerous sociocultural changes that take place during the teen years.

Somerville and colleagues wanted to investigate whether just being looked at -- a minimal social-evaluation situation -- might register with greater importance, arousal, and intensity for adolescents than for either children or adults. The researchers hypothesized that late-developing regions of the brain, such as the medial prefrontal cortex (MPFC), could play a unique role in the way teens monitor these types of social evaluative contexts.

The researchers had 69 participants, ranging in age from 8 to almost 23 years old, come to the lab and complete measures that gauged emotional, physiological, and neural responses to social evaluation.

They told the participants that they would be testing a new video camera embedded in the head coil of a functional MRI scanner. The participants watched a screen indicating whether the camera was "off," "warming up," or "on," and were told that a same-sex peer of about the same age would be watching the video feed and would be able to see them when the camera was on. In reality, there was no camera in the MRI machine.

The consistency and strength of the resulting data took the researchers by surprise: "We were concerned about whether simply being looked at was a strong enough 'social evaluation' to evoke emotional, physiological and neural responses," says Somerville. "Our findings suggest that being watched, and to some extent anticipating being watched, were sufficient to elicit self-conscious emotional responses at each level of measurement."

Specifically, participants' self-reported embarrassment, physiological arousal, and MPFC activation showed reactivity to social evaluation that seemed to converge and peak during adolescence.

Adolescent participants also showed increased functional connectivity between the MPFC and striatum, an area of the brain that mediates motivated behaviors and actions. Somerville and colleagues speculate that the MPFC-striatum pathway may be a route by which social evaluative contexts influence behavior. The link may provide an initial clue as to why teens often engage in riskier behaviors when they're with their peers.

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2013年7月2日星期二

Scientists help explain visual system's remarkable ability to recognize complex objects

July 2, 2013 — How is it possible for a human eye to figure out letters that are twisted and looped in crazy directions, like those in the little security test internet users are often given on websites?

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It seems easy to us -- the human brain just does it. But the apparent simplicity of this task is an illusion. The task is actually so complex, no one has been able to write computer code that translates these distorted letters the same way that neural networks can. That's why this test, called a CAPTCHA, is used to distinguish a human response from computer bots that try to steal sensitive information.

Now, a team of neuroscientists at the Salk Institute for Biological Studies has taken on the challenge of exploring how the brain accomplishes this remarkable task. Two studies published within days of each other demonstrate how complex a visual task decoding a CAPTCHA, or any image made of simple and intricate elements, actually is to the brain.

The findings of the two studies, published June 19 in Neuron and June 24 in the Proceedings of the National Academy of Sciences (PNAS), take two important steps forward in understanding vision, and rewrite what was believed to be established science. The results show that what neuroscientists thought they knew about one piece of the puzzle was too simple to be true.

Their deep and detailed research -- -involving recordings from hundreds of neurons -- -may also have future clinical and practical implications, says the study's senior co-authors, Salk neuroscientists Tatyana Sharpee and John Reynolds.

"Understanding how the brain creates a visual image can help humans whose brains are malfunctioning in various different ways -- -such as people who have lost the ability to see," says Sharpee, an associate professor in the Computational Neurobiology Laboratory. "One way of solving that problem is to figure out how the brain -- -not the eye, but the cortex -- -- processes information about the world. If you have that code then you can directly stimulate neurons in the cortex and allow people to see."

Reynolds, a professor in the Systems Neurobiology Laboratory, says an indirect benefit of understanding the way the brain works is the possibility of building computer systems that can act like humans.

"The reason that machines are limited in their capacity to recognize things in the world around us is that we don't really understand how the brain does it as well as it does," he says.

The scientists emphasize that these are long-term goals that they are striving to reach, a step at a time.

Integrating parts into wholes

In these studies, Salk neurobiologists sought to figure out how a part of the visual cortex known as area V4 is able to distinguish between different visual stimuli even as the stimuli move around in space. V4 is responsible for an intermediate step in neural processing of images.

"Neurons in the visual system are sensitive to regions of space -- -- they are like little windows into the world," says Reynolds. "In the earliest stages of processing, these windows -- -known as receptive fields -- -are small. They only have access to information within a restricted region of space. Each of these neurons sends brain signals that encode the contents of a little region of space -- -they respond to tiny, simple elements of an object such as edge oriented in space, or a little patch of color."

Neurons in V4 have a larger receptive field that can also compute more complex shapes such as contours. They accomplishes this by integrating inputs from earlier visual areas in the cortex -- -that is, areas nearer the retina, which provides the input to the visual system, which have small receptive fields, and sends on that information for higher level processing that allow us to see complex images, such as faces, he says.

Both new studies investigated the issue of translation invariance -- -- the ability of a neuron to recognize the same stimulus within its receptive field no matter where it is in space, where it happens to fall within the receptive field.

The Neuron paper looked at translation invariance by analyzing the response of 93 individual neurons in V4 to images of lines and shapes like curves, while the PNAS study looked at responses of V4 neurons to natural scenes full of complex contours.

Dogma in the field is that V4 neurons all exhibit translation invariance.

"The accepted understanding is that individuals neurons are tuned to recognize the same stimulus no matter where it was in their receptive field," says Sharpee.

For example, a neuron might respond to a bit of the curve in the number 5 in a CAPTCHA image, no matter how the 5 is situated within its receptive field. Researchers believed that neuronal translation invariance -- -the ability to recognize any stimulus, no matter where it is in space -- -increases as an image moves up through the visual processing hierarchy.

"But what both studies show is that there is more to the story," she says. "There is a trade off between the complexity of the stimulus and the degree to which the cell can recognize it as it moves from place to place."

A deeper mystery to be solved

The Salk researchers found that neurons that respond to more complicated shapes -- -like the curve in 5 or in a rock -- -- demonstrated decreased translation invariance. "They need that complicated curve to be in a more restricted range for them to detect it and understand its meaning," Reynolds says. "Cells that prefer that complex shape don't yet have the capacity to recognize that shape everywhere."

On the other hand, neurons in V4 tuned to recognize simpler shapes, like a straight line in the number 5, have increased translation invariance. "They don't care where the stimuli they are tuned to is, as long as it is within their receptive field," Sharpee says.

"Previous studies of object recognition have assumed that neuronal responses at later stages in visual processing remain the same regardless of basic visual transformations to the object's image. Our study highlights where this assumption breaks down, and suggests simple mechanisms that could give rise to object selectivity," says Jude Mitchell, a Salk research scientist who was the senior author on the Neuron paper.

"It is important that results from the two studies are quite compatible with one another, that what we find studying just lines and curves in one first experiment matches what we see when the brain experiences the real world," says Sharpee, who is well known for developing a computational method to extract neural responses from natural images.

"What this tells us is that there is a deeper mystery here to be solved," Reynolds says. "We have not figured out how translation invariance is achieved. What we have done is unpacked part of the machinery for achieving integration of parts into wholes."

Minjoon Kouh, a former postdoctoral fellow at Salk, participated in the PNAS study. Salk postdoctoral researcher Anirvan Nandy and senior staff scientist Jude Mitchell, of the Salk Systems Neurobiology Laboratory, were co-authors of the Neuron paper.

Both studies were funded by grants from the National Institutes of Health (R01EY019493), the McKnight Scholarship and the Ray Thomas Edwards and W. M. Keck Foundations. In addition, the PNAS study received a grant from the Searle Funds. The Neuron study was additionally funded by grants from the Alfred P. Sloan Foundation, the National Institutes of Health (EY0113802), the Gatsby Charitable Foundation and the Schwartz Foundation, and a Pioneer Fund postdoctoral fellowship.

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New way discovered to block inflammation

July 1, 2013 — Researchers at NYU Langone Medical Center have discovered a mechanism that triggers chronic inflammation in Alzheimer's, atherosclerosisand type-2 diabetes. The results, published today in Nature Immunology, suggest a common biochemical thread to multiple diseases and point the way to a new class of therapies that could treat chronic inflammation in these non-infectious diseases without crippling the immune system. Alzheimer's, atherosclerosis and type-2 diabetes -- diseases associated with aging and inflammation -- affect more than 100 million Americans.

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When the body encounters a pathogen, it unleashes a rush of chemicals known as cytokines that draws immune cells to the site of infection and causes inflammation. Particulate matter in the body, such as the cholesterol crystals associated with vascular disease and the amyloid plaques that form in the brain in Alzheimer's disease, can also cause inflammation but the exact mechanism of action remains unclear. Researchers previously thought that these crystals and plaques accumulate outside of cells, and that macrophages -- immune cells that scavenge debris in the body -- induce inflammation as they attempt to clear them.

"We've discovered that the mechanism causing chronic inflammation in these diseases is actually very different," says Kathryn J. Moore, PhD, senior author of the study and associate professor of medicine and cell biology, Leon H. Charney Division of Cardiology at NYU Langone Medical Center.

The researchers found that particulate matter does not linger on the outside of cells. Instead, a receptor called CD36 present on macrophages draws the soluble forms of these particles inside the cell where they are transformed into substances that trigger an inflammatory response. Says Dr. Moore, "What we found is that CD36 binds soluble cholesterol and protein matter associated with these diseases, pulls them inside the cell, and then transforms them. The resulting insoluble crystals and amyloid damage the macrophage and trigger a powerful cytokine, called interleukin-1B, linked to a chronic inflammatory response."

These findings hold exciting clinical implications.When the researchers blocked the CD36 receptor in mice with atherosclerosis (in which cholesterol thickens the arteries), the cytokine response declined, fewer cholesterol crystals formed in plaques, and inflammation decreased. Consequently, atherosclerosis also abated.

Other less-targeted strategies to control inflammation may hamper the immune response, but the CD36 strategy spares certain cytokines to fight off pathogens, while blocking CD36's ability to trigger interleukin-1B.

"Our findings identify CD36 as a central regulator of the immune response in these conditions and suggest that blocking CD36 might be a common therapeutic option for all three diseases," says Dr. Moore.

Support for this work comes from The National Institutes of Health and the American Heart Association.

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Curious mix of precision and brawn in a pouched super-predator

Australian and American marsupials are among the closest living relatives of the extinct Thylacosmilus atrox, which had tooth roots extending rearwards almost into its small braincase.

"Thylacosmilus looked and behaved like nothing alive today," says UNSW palaeontologist, Dr Stephen Wroe, leader of the research team.

"To achieve a kill the animal must have secured and immobilised large prey using its extremely powerful forearms, before inserting the sabre-teeth into the windpipe or major arteries of the neck -- a mix of brute force and delicate precision."

The iconic North American sabre-toothed 'tiger', Smilodon fatalis, is often regarded as the archetypal mammalian super-predator.

However, Smilodon -- a true cat -- was just the end point in one of at least five independent 'experiments' in sabre-tooth evolution through the Age of Mammals, which spanned some 65 million years.

Thylacosmilus atrox is the best preserved species of one of these evolutionary lines -- pouched sabre-tooths that terrorised South America until around 3.5 million years ago.

For its size, its huge canine teeth were larger than those of any other known sabre-tooth.

Smilodon's killing behaviour has long attracted controversy, but scientists now mostly agree that powerful neck muscles, as well as jaw muscles, played an important role in driving the sabre-teeth into the necks of large prey.

Little was known about the predatory behaviour in the pouched Thylacosmilus.

To shed light on this super-predator mystery, Dr Wroe's team of Australian and US scientists constructed and compared sophisticated computer models of Smilodon and Thylacosmilus, as well as a living conical-toothed cat, the leopard.

These models were digitally 'crash-tested' in simulations of biting and killing behaviour. The results are published in the journal PLoS ONE.

"We found that both sabre-tooth species were similar in possessing weak jaw-muscle-driven bites compared to the leopard, but the mechanical performance of the sabre-tooths skulls showed that they were both well-adapted to resist forces generated by very powerful neck muscles," says Dr Wroe.

"But compared to the placental Smilodon, Thylacosmilus was even more extreme."

"Frankly, the jaw muscles of Thylacosmilus were embarrassing. With its jaws wide open this 80-100 kg 'super-predator' had a bite less powerful than a domestic cat. On the other hand -- its skull easily outperformed that of the placental Smilodon in response to strong forces from hypothetical neck muscles."

"Bottom line is that the huge sabres of Thylacosmilus were driven home by the neck muscles alone and -- because the sabre-teeth were actually quite fragile -- this must have been achieved with surprising precision."

"For Thylacosmilus -- and other sabre-tooths -- it was all about a quick kill."

"Big prey are dangerous -- even to super-predators -- and the faster the kill the less likely it is that the predator will get hurt -- or for that matter attract unwanted attention from other predators."

"It may not have been the smartest of mammalian super-predators -- but in terms of specialisation -- Thylacosmilus took the already extreme sabre-tooth lifestyle to a whole new level," says Dr Wroe.

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2013年7月1日星期一

Climate change: Disequilibrium will become the norm in the plant communities of the future

This has been demonstrated by a new synthesis carried out by two researchers at Aarhus University -- Professor of Biology Jens-Christian Svenning and Assistant Professor Brody Sandel.

Professor Svenning explains: "In the climate debate, even researchers have had a tendency to overlook the fact that ecological dynamics can be slow. However, our forests take an extremely long time to adapt. For example, we still have a small amount of small-leaved lime in Denmark, which has held on since the warm period during the Bronze Age, i.e. about 3000 years. Perhaps it will now get another chance to spread when the summers once more get warmer. However, such expansion would take a long time, as lime is not a particularly fast-growing tree or particularly good at dispersing, even under optimum conditions. The climate will change considerably in the course of a single tree generation so we should not assume that the forest we're looking at in a given place is suitable for the climate. Future climate will constantly shift, which will increasingly result in these strange situations of disequilibrium."

Even fast spreaders such as some invasive exotic plants remain in disequilibrium for decades or centuries. Shown here is a Norway maple, a highly invasive tree species in North America that may nevertheless still take many decades to spread across even small landscapes.

The challenges we face

"Consequently, if you're trying to practise natural forest management with natural regeneration, you may see completely different plants regenerating compared with what you had before, because the climate has shifted to become suitable for another set of species. This also makes it challenging to adhere to a management plan granting preservation status to a particular type of nature at a certain site. At such a site, the existence of a large number of fully grown specimens of an endangered species is no guarantee that there will be a next generation.

This would be challenging for everyone -- for the managers, for the people who use the countryside in one way or another, and also for the researchers who are used to working with ecosystems that are much more balanced. Plant life and ecosystems will become much more dynamic and often out of sync with the climate.

We're causing so many changes to the climate, but at the same time nature is SO slow. Just think of a tree generation. Our entire culture is based on something that was, if not in complete equilibrium, then at least relatively predictable. We're used to a situation where flora, fauna and climate are reasonably well matched. In future, this equilibrium will shift on an ongoing basis, and there will be plenty of mismatches. That's what we'll have to work with."

Professor Svenning also calls for caution: "With nature in such a state of disequilibrium, human introduction of new species will play a key role. Take cherry laurel, for example, which we see in many gardens in Denmark. It's ready to spread throughout the Danish countryside. If it were to migrate unaided from its nearest native site in South-East Europe to Denmark, it would take thousands of years. Horticulturists now help it along. This will help the species survive, but can also cause northern species in Denmark to become extinct more rapidly. The cherry laurel is an evergreen, and if it disperses on the forest floor, it may create too much shade for the existing flora on the forest floor to survive. At the same time, the disequilibrium presents the advantage that such dispersal will take decades despite the contribution of horticulturists," Professor Svenning concludes.

Cherry laurel is another example of a species that has not yet returned to Northern Europe since the last Ice Age, but which we have helped along by planting in our gardens. Here it was found in the English countryside. Photo: Jens-Christian Svenning, Aarhus University.

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Rocket-launched camera reveals highways and sparkles in the solar atmosphere

With partners in the United States and Russia, the UCLan team used a sounding rocket to launch the NASA High Resolution Coronal Imager (Hi-C) from the White Sands Missile Range in New Mexico, USA. During its short flight, the Hi-C team obtained images of the solar atmosphere (the solar corona) five times sharper than anything seen before and acquired data at a rate of about one image every five seconds.

The new camera observed the Sun in extreme ultraviolet light and focused on a large, magnetically-active sunspot region. Images from Hi-C reveal a number of new features in the corona, including 'blobs' of gas ricocheting along 'highways' and bright dots that switch on and off rapidly which the group call 'sparkles'.

In the new images, small clumps of electrified gas (plasma) at a temperature of about one million degrees Celsius are seen racing along highways shaped by the Sun's magnetic field. These blobs travel at around 80 km per second (the equivalent of 235 times the speed of sound on Earth), fast enough to travel the distance from Glasgow to London in 7 seconds. The highways are 450 km across, roughly the length of Ireland from north to south.

The flows of material are inside a so-called solar filament, a region of dense plasma that can erupt outwards from the Sun. These eruptions, known as coronal mass ejections (CMEs), carry billions of tonnes of plasma into space. If a CME travels in the right direction it can interact with Earth, disturbing the terrestrial magnetic field in a 'space weather' event that can have a range of destructive consequences from damaging satellite electronics to overloading power grids on the ground. The discovery and nature of the solar highways allows scientists to better understand the driving force for these eruptions and help predict with greater accuracy when CMEs might take place.

Another new set of images could help explain an enduring mystery of the Sun. Astronomers have long struggled to understand why, with a temperature of two million degrees, the corona is around 400 times hotter than the solar surface. Hi-C images reveal dynamic bright dots which switch on and off at high speed.

These 'sparkles' typically last around 25 seconds, are about 680 km across (the size of the UK) and release at least 1024 (one million million million million) Joules of energy in each event, or around 10,000 times the annual energy consumption of the population of the UK (based on information from the UK Department of Energy and Climate Change). The sparkles are thus a clear signal that enormous amounts of energy are being added into the corona and may then be released violently to heat the plasma.

Solar physicist Professor Robert Walsh, UCLan's University Director of Research, added: "I'm incredibly proud of the work of my colleagues in developing Hi-C. The camera is effectively a microscope that lets us view small scale events on the Sun in unprecedented detail. For the first time we can unpick the detailed nature of the solar corona, helping us to predict when outbursts from this region might head towards the Earth."

NASA Marshall heliophysicist Dr Jonathan Cirtain, principal investigator for the Hi-C mission said: "Our team developed an exceptional instrument capable of revolutionary image resolution of the solar atmosphere. We took advantage of the high level of solar activity to focus in on an active sunspot and obtained these remarkable pictures."

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Different neuronal groups govern right-left alternation when walking

Most land animals can walk or run by alternating their left and right legs in different coordinated patterns. Some animals, such as rabbits, move both leg pairs simultaneously to obtain a hopping motion. In the present study, the researchers Adolfo Talpalar and Julien Bouvier together with professor Ole Kiehn and colleagues, have studied the spinal networks that control these movement patterns in mice. By using advanced genetic methods that allow the elimination of discrete groups of neurons from the spinal cord, they were able to remove a type of neurons characterized by the expression of the gene Dbx1.

"It was classically thought that only one group of nerve cells controls left right alternation," says Ole Kiehn who leads the laboratory behind the study at the Department of Neuroscience. "It was then very interesting to find that there are actually two specific neuronal populations involved, and on top of that that they each control different aspect of the limb coordination."

Indeed, the researchers found that the gene Dbx1 is expressed in two different groups of nerve cells, one of which is inhibitory and one that is excitatory. The new study shows that the two cellular populations control different forms of the behaviour. Just like when we change gear to accelerate in a car, one part of the neuronal circuit controls the mouse's alternating gait at low speeds, while the other population is engaged when the animal moves faster. Accordingly, the study also show that when the two populations are removed altogether in the same animal, the mice were unable to alternate at all, and hopped like rabbits instead.

There are some animals, such as desert mice and kangaroos, which only hop. The researchers behind the study speculate that the locomotive pattern of these animals could be attributable to the lack of the Dbx1 controlled alternating system.

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