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  • richardmitnick 1:13 pm on February 13, 2018 Permalink | Reply
    Tags: , Kikai Caldera, Science Alert,   

    From Science Alert: “There’s an Absolutely Massive Lava Dome Lurking Underneath Japan 

    ScienceAlert

    Science Alert

    12 FEB 2018
    PETER DOCKRILL

    1
    (Hydrographic and Oceanographic Department/Japan Coast Guard)

    The Kikai Caldera, located to the south of Japan’s main islands, devastated a large swathe of the Japanese archipelago when it spewed upwards of 500 cubic kilometres (120 cubic miles) of magma during the Akahoya eruption some 7,000 years ago – and scientists have just confirmed evidence of new volcanic activity under the crater.

    2
    Relief map of Kikai Caldera, Kagoshima prefecture, Japan. 28 February 2016. NASA’s Shuttle Radar Topography Mission. Batholith (Wikipedia)

    Researchers at Kobe University have detected a giant lava dome that exists below the Kikai Caldera, holding a volume of more than 32 cubic kilometres (almost 8 cubic miles) of trapped magma – a buildup that could reveal clues as to when Kikai’s next super-eruption may be unleashed.

    “The most serious problem that we are worrying about is not an eruption of this lava dome, but the occurrence of the next super-eruption,” volcanologist Yoshiyuki Tatsumi told The New York Times.

    4
    (Kobe University)

    The findings are reported in Scientific Reports.

    According to Tatsumi’s previous research, given Japan’s level of active volcanism, there is about a 1 percent chance of a “catastrophic” caldera eruption occurring within the Japanese archipelago sometime during the next 100 years – an event that could endanger or disrupt as many as 110 million people.

    Such eruptions don’t come along very often, but they do happen, with the the Kikai Caldera having undergone two massive such incidents prior to the Akahoya eruption – one about 95,000 years ago, following another super-eruption some 140,000 years back.

    The confirmation of this lava dome – detected across three separate survey voyages by sonar, underwater robot observations, and seismic reflection analyses – doesn’t mean any kind of super-eruption is necessarily imminent, but the researchers suspect it is evidence of a new magma buildup.

    “The lava dome is chemically different from the super-eruption, suggesting that a new magma supply system had been developed after 7,300 years ago,” Tatsumi told The New York Times.

    In other words, whatever the significance of the lava dome is, this volume of hot, viscous rock – standing some 600 metres (1,968 feet) tall and spanning a width of 10 kilometres (6.2 miles) – isn’t an echo of Akahoya, but something new taking shape under the East China Sea.

    “The post-caldera activity, at least [at] this caldera, is regarded as the preparation stage to the next super-eruption,” Tatsumi explained to Live Science, “not as the calming-down stage from the previous super-eruption.”

    Just what this activity portends is unclear for now, and at least one researcher has pointed out that we could be looking at a congregation of smaller lava domes, as opposed to one giant combined mass.

    To investigate further, Tatsumi and fellow researchers will embark on another expedition to the Kikai site next month, to see what further analysis reveals – and hopefully then we’ll get a clearer picture on how this magma activity feeds into the caldera’s evolution as a whole.

    See the full article here .

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  • richardmitnick 8:02 am on February 10, 2018 Permalink | Reply
    Tags: , Lake Under The Sea - Those Who Swim There Won't Come Back Alive, , Science Alert   

    From Science Alert: “Scientists Have Found a Lake Under The Sea – Those Who Swim There Won’t Come Back Alive” 

    ScienceAlert

    Science Alert

    9 FEB 2018
    JOHN STANLEY HUNTER
    MARION LENKE

    1
    EVNautilus/YouTube

    Scientists have discovered a ‘lake’ in the Gulf of Mexico. Everyone, who enters this pool at the bottom of the sea will suffer horribly.

    Erik Cordes, associate professor of biology at Temple University, has researched the pool and described his findings in the journal Oceanography.

    “It was one of the most amazing things in the deep sea. You go down into the bottom of the ocean and you are looking at a lake or a river flowing. It feels like you are not on this world”, Cordes told Seeker.

    The water in the ‘lake within the sea’ is about five times as salty as the water surrounding it. It also contains highly toxic concentrations of methane and hydrogen sulphide and can thus not mix with the surrounding sea.

    For animals (and people) who swim into it, these toxic concentrations can be deadly. Only bacterial life, tube worms, and shrimp can survive those circumstances.

    For scientists, this lake is like a playground for their research. They can explore how certain organisms can survive in extreme habitats.

    “There’s a lot of people looking at these extreme habitats on Earth as models for what we might discover when we go to other planets,” Cordes told Seeker.

    See the full article here .

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  • richardmitnick 11:43 am on February 8, 2018 Permalink | Reply
    Tags: , Harvesting Earth's Energy, Quantum Tunnelling, Science Alert   

    From Science Alert: “We Can Now Harvest Electricity From Earth’s Heat Using Quantum Tunnelling” 

    ScienceAlert

    Science Alert

    8 FEB 2018
    DAVID NIELD

    1
    (pixelparticle/Shutterstock)

    Researchers have come up with a way we could harvest energy from Earth by turning excess infrared radiation and waste heat into electricity we can use.

    The concept involves the strange physics of quantum tunnelling, and key to the idea is a specially designed antenna that can detect waste or infrared heat as high-frequency electromagnetic waves, transforming these quadrillionth-of-a-second wave signals into a direct charge.

    There’s actually a lot of energy going to waste here on Earth – most sunlight that hits the planet gets sucked up by surfaces, the oceans, and our atmosphere.

    This warming leads to a constant leak of infrared radiation that some estimate to be as much as millions of gigawatts every second.

    Because the infrared wavelengths are so short, to harness them we need super-tiny antennas. According to the international team of researchers behind the new study, it’s quantum tunnelling that could provide the breakthrough required.

    “There is no commercial diode in the world that can operate at such high frequency,” says lead researcher Atif Shamim from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. “That’s why we turned to quantum tunnelling.”

    Quantum tunnelling is a well-established phenomenon in quantum physics where a particle can get through a barrier without having enough energy to do so.

    One of the examples used most often is of a ball rolling up a hill: in classical physics, the ball needs a certain amount of energy behind it to get up the hill and over to the other side.

    But in quantum physics, the ball can tunnel through the hill with less energy, thanks to the positional uncertainty that’s at the heart of everything quantum.

    How does this help in the construction of nanoscale antennas? It enables electrons to be moved through a small barrier, via a tunnelling device like a metal-insulator-metal (MIM) diode, turning infrared waves into current along the way.

    The scientists were able to create a new bowtie-shaped nanoantenna, sandwiching the thin insulator film between two slightly overlapped metallic arms made from gold and titanium, giving them a device capable of generating the intense electrical fields required for tunnelling to work.

    2
    (KAUST)

    “The most challenging part was the nanoscale overlap of the two antenna arms, which required very precise alignment,” says one of the researchers, Gaurav Jayaswal from KAUST.

    “Nonetheless, by combining clever tricks with the advanced tools at KAUST’s nanofabrication facility we accomplished this step.”

    The newly created MIM diode was able to successfully capture infrared radiation with zero applied voltage, so it only turns on when needed.

    While conventional solar panels can only harvest a small chunk of the visible light spectrum, being able to tap into all that excess infrared radiation as well would represent a revolutionary shift in energy production, a “game changer” in the words of the researchers.

    What’s more, unlike solar power plants, these energy harvesters could operate around the clock, whatever the weather. Other scientists are working on cracking the same problem from different angles.

    Despite the huge promise, for the time being this is just another step along the road to figuring this out, and many technical challenges still lie ahead – currently, the antenna isn’t very energy efficient, for example.

    “This is just the beginning – a proof of concept,” says Shamim.

    Eventually, though, the tech could make a huge difference. “We could have millions of such devices connected to boost overall electricity generation,” he adds.

    The research has been published in Materials Today Energy.

    See the full article here .

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  • richardmitnick 11:28 am on February 8, 2018 Permalink | Reply
    Tags: , , , Science Alert   

    From Science Alert: “This New Autism Genetics Study Could Help Explain Why It’s Such a Huge Spectrum” 

    ScienceAlert

    Science Alert

    8 FEB 2018
    MIKE MCRAE

    1
    (Olesia Bilkei/Shutterstock)

    Genes responsible for a number of autism’s characteristics come in two varieties, which could help explain not only the condition’s diversity, but also how it’s inherited.

    A new study on the genetics behind the disorder has revealed the kinds of mutations associated with lower IQ are also linked with impeded motor skills.

    What’s more, the severity of these mutations might also explain why many aspects of autism spectrum disorder (ASD) are more pronounced in some than in others.

    In most cases, a diagnosis for ASD is based on a mix of social and physical behaviours, including difficulties in communicating and sensory processing, repetitive movements, and impeded motor functions.

    “Diminished motor skills appear to be an almost universal property of children with autism,” says molecular geneticist Michael Wigler from Cold Spring Harbor Laboratory.

    Yet there are also traits that commonly coincide with an ASD diagnosis, without necessarily being considered as a defining part of the condition.

    For example, intellectual and learning disabilities can affect a significant proportion of individuals with ASD, with just under half of those with a diagnosis also having an IQ lower than 70.

    But it’s still something of a mystery as to what really gives rise to this rich spectrum of characteristics.

    There are strong implications that a number of genes are involved, and that numerous epigenetic changes can be responsible for switching them on and off.

    Many of these genetic changes are known to be inherited, but past research has linked so-called de novo mutations – coding differences that aren’t found in the parents – with learning difficulties among those with ASD.

    Another recent study [AJHG] also concluded that de novo mutations happening after fertilisation could account for as much as 2 percent of all autism diagnoses.

    Researchers have now used a database consisting of over 2,700 families who had only one child affected by ASD to discover that de novo mutations in key genes can also accurately predict the presence and severity of reduced motor skills.

    The same link wasn’t found for other components of ASD, such as social skills and challenges in communication, meaning the genes for those autism traits are more likely to be passed on from the parents.

    The discovery adds much needed detail to what is an incredibly complex condition, and could even help explain how it persists in our population.

    One possibility is that some of the more challenging aspects of ASD could be offset by having a higher intelligence.

    There is already speculation that there is a strong interplay between IQ and autism’s core characteristics – where social skills make it difficult for researchers to accurately predict cognitive abilities.

    By the same token, the researchers suggest having strong cognitive and motor skills could in turn affect how other autism behaviours are expressed.

    The end result could mean we’re more likely to pass on genes that impact on social and communication skills so long as they’re not accompanied by genes that also affect IQ or interfere with movements.

    In other words, those genes giving rise to learning difficulties or affecting motor control are more likely to occur through de-novo mutations rather than inheritance.

    On a more practical level, the research has implications for studying the inheritance of ASD, as well as diagnosing the disorder.

    The scientists suggest a new way to classify ASD based on its genetic foundations – mild, with little impairment of either motor skills or IQ, moderate impairment mainly to motor skills, and severe impairment, affecting both.

    They also emphasise the importance of evaluating IQ and motor skills when forming a diagnosis and designing therapies.

    “As such, objective assessment of cognitive function should be a facet of any clinical evaluation of the patient,” says Wigler.

    This research was published in the Proceedings of the National Academy of Sciences.

    See the full article here .

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  • richardmitnick 8:06 am on January 31, 2018 Permalink | Reply
    Tags: , , Earth Went Strangely Quiet About 2 Billion Years Ago And We Don't Know Why, , Science Alert   

    From Science Alert: “Earth Went Strangely Quiet About 2 Billion Years Ago And We Don’t Know Why” 

    ScienceAlert

    Science Alert

    31 JAN 2018
    MIKE MCRAE

    1
    (Vadim Sadovski/Shutterstock)

    A new study has added evidence to the hypothesis that our planet experienced a lull in geology between 2.2 and 2.3 billion years ago, when not a lot went on as far as rock-forming processes go.

    The relatively dormant phase in our planet’s history signals a significant change in tectonics, one that is fuelling discussion on exactly how continents form and could possibly provide better details on exactly where we can find new deposits of various mineral resources.

    The era known as the Palaeoproterozoic covers a rather exciting time in Earth’s history, starting 2.5 billion years ago and ending around a billion years later.

    Life was literally a lot simpler then. Days were four hours shorter. Our atmosphere was yet to have a lot of oxygen. There were the first global glaciation events. And the planet’s first supercontinent – a huge chunk of land called Columbia, or Nuna – was in the process of being formed.

    As you might imagine, geologists are keen to understand how this far younger Earth behaved compared to today’s more mature globe.

    It seems as if around 2.45 billion years ago, there was something of a quiet spell beneath the surface, one that lasted around 250 million years.

    Not that everybody is convinced – other interpretations of the research suggest it was business as usual throughout the Palaeoproterozoic [Earth and Planetary Science Letters].

    With the jury still out, more evidence is needed. Which is just what a new study led by researchers from Curtin University has provided.

    A close look at the existing data as well as new rock samples collected from Western Australia, China, Northern Canada and Southern Africa has added weight to what’s described as a tectono-magmatic shutdown.

    “Our research shows a bona fide gap in the Palaeoproterozoic geologic record, with not only a slowing down of the number of volcanoes erupting during this time, but also a slow-down in sedimentation and a noticeable lull in tectonic plate movement,” says Curtin University geoscientist Christopher Spencer.

    Earth’s guts were a lot hotter a few billion years ago. For a while all that churning resulted in a whole lot of volcanic activity.

    Whether that directly led to significant cooling, or if something else happened beneath the crust, nobody is sure.

    But we can now be fairly confident that about 2.3 billion years ago, things went quiet under the lid. Volcanoes were temporarily out of fashion. Plate movements were subdued.

    Earth was taking a break.

    “This ‘dormant’ period lasted around 100 million years and signalled what we believe was a shift from ‘ancient-style’ tectonics to ‘modern-style’ tectonics more akin to those operating in the present day,” says Spencer.

    “It’s almost as if the Earth experienced a mid-life crisis.”

    After a bit of a breather, things ramped up again. Chunks of ancient crust fractured into smaller pieces called cratons, which can today be found deep inside continental plates.

    “Following this dormant period Earth’s geology started to ‘wake-up’ again around 2.2 to 2.0 billion years ago with a ‘flare-up’ of volcanic activity and a shift in the composition of the continental crust,” says Spencer.

    Why did the mantle ‘flare up’ again after a quiet spell? The researchers aren’t sure, but have speculated it might simply come down to a surge of accumulated heat.

    Understanding the geological processes that led from ‘supercratons’ to the first supercontinent could help us understand how many of the mineral resources we rely upon formed and distributed.

    More data is needed to fill in missing details on this geological ‘mid-life crisis’ model, but we can at least be grateful Earth didn’t quit its job and run off with some young moon.

    This research was published in Nature Geoscience.

    See the full article here .

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  • richardmitnick 8:17 am on January 22, 2018 Permalink | Reply
    Tags: , , Mounting Evidence Suggests a Remote Australian Region Was Once Part of North America, Science Alert   

    From Science Alert: “Mounting Evidence Suggests a Remote Australian Region Was Once Part of North America” 

    ScienceAlert

    Science Alert

    22 JAN 2018
    MICHELLE STARR

    1
    (Janaka Dharmasena/Shutterstock)

    It really is a small world after all.

    Geologists tend to agree that, billions of years ago, the configuration of the continents was very different. How exactly they all fit together and when is a bit more of a puzzle, the pieces of which can be put together by studying rocks and fossils.

    Now researchers have found a series of rocks that show something surprising: part of Australia could have once been connected to part of Canada on the North American continent, around 1.7 billion years ago.

    Actually, the discovery that the two continents were once connected isn’t hugely surprising. Speculation about such a connection has existed since the late 1970s, when a paper proposed a connection dating back to the continent of Rodinia, around 1.13 billion years ago. However, an exact time and location for the connection has remained under debate.

    Found in Georgetown, a small town of just a few hundred people in the north east of Australia, the rocks are unlike other rocks on the Australian continent.

    Instead, they show similarities to ancient rocks found in Canada, in the exposed section of the continental crust called the Canadian Shield.

    This unexpected finding, according to researchers at Curtin University, Monash University and the Geological Survey of Queensland in Australia, reveals something about the composition of the ancient supercontinent Nuna.

    “Our research shows that about 1.7 billion years ago, Georgetown rocks were deposited into a shallow sea when the region was part of North America. Georgetown then broke away from North America and collided with the Mount Isa region of northern Australia around 100 million years later,” said Curtin PhD student and lead researcher Adam Nordsvan.

    “This was a critical part of global continental reorganisation when almost all continents on Earth assembled to form the supercontinent called Nuna.”

    The last time the continents were close to one another was the major supercontinent known as Pangea, which broke apart around 175 million years ago.

    However, before Pangea, the planet went through a number of supercontinent configurations – one of which was Nuna, also called Columbia, which existed from around 2.5 billion to 1.5 billion years ago.

    The team reached its conclusion by examining new sedimentological field data, and new and existing geochronological data from both Georgetown and Mount Isa, another remote town in north east Australia, and comparing it to rocks from Canada.

    According to the research, when Nuna started breaking up, the Georgetown area remained permanently stuck to Australia.

    This, the researchers said in their paper, challenges the current model that suggests the Georgetown region was part of the continent that would become Australia prior to 1.7 billion years ago.

    The research also found new evidence that Georgetown and Mount Isa mountain ranges were formed when the two regions collided.

    “Ongoing research by our team shows that this mountain belt, in contrast to the Himalayas, would not have been very high, suggesting the final continental assembling process that led to the formation of the supercontinent Nuna was not a hard collision like India’s recent collision with Asia,” said co-author Zheng-Xiang Li.

    “This new finding is a key step in understanding how Earth’s first supercontinent Nuna may have formed, a subject still being pursued by our multidisciplinary team here at Curtin University.”

    The research has been published in the journal Geology.

    See the full article here .

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  • richardmitnick 7:48 am on January 22, 2018 Permalink | Reply
    Tags: , , , , , New Study on Black Hole Magnetic Fields Has Thrown a Huge Surprise at Astronomers, Science Alert   

    From Science Alert: “New Study on Black Hole Magnetic Fields Has Thrown a Huge Surprise at Astronomers” 

    ScienceAlert

    Science Alert

    22 JAN 2018
    MICHELLE STARR

    For the first time, scientists have studied the magnetic field of a black hole inside the Milky Way in multiple wavelengths – and found that it doesn’t conform to what we previously thought.

    1
    X-ray echoes during V404 Cygni’s feeding event in 2015. (Andrew Beardmore & NASA/Swift)

    NASA Neil Gehrels Swift Observatory

    According to researchers at the University of Florida and the University of Texas at San Antonio, the black hole called V404 Cygni’s magnetic field is much weaker than expected – a discovery that means we may have to rework our current models for black hole jets.

    V404 Cygni, located around 7,800 light-years away in the constellation of Cygnus, is a binary microquasar system consisting of a black hole about 9 times the mass of the Sun, and its companion star, an early red giant slightly smaller than the Sun.

    In 2015, the system flared into life, and, over the course of about a week, periodically flashed with activity as the black hole devoured material from its companion star.

    At times, it was the brightest X-ray object in the sky; but it also showed, according to NASA-Goddard’s Eleonora Troja, “exceptional variation at all wavelengths” – offering a rare opportunity to study both V404 Cygni and black hole feeding activity.

    It was this period that the team, led by Yigit Dallilar at the University of Florida, studied.

    When black holes are active, they become surrounded by a brightly glowing accretion disc, lit by the gravitational and frictional forces that heat the material as it swirls towards the black hole.

    As they consume matter, black holes expel powerful jets of plasma at near light-speed from the coronae – regions of hot, swirling gas above and below the accretion disc.

    Previous research [Astronomy] has shown that these coronae and the jets are controlled by powerful magnetic fields – and the stronger the magnetic fields close to the black hole’s event horizon, the brighter its jets.

    This is because the magnetic fields are thought to act like a synchrotron, accelerating the particles that travel through it.

    Dallilar’s team studied V404 Cygni’s 2015 feeding event across optical, infrared, X-ray and radio wavelengths, and found rapid synchrotron cooling events that allowed them to obtain a precise measurement of the magnetic field.

    Their data revealed a much weaker magnetic field than predicted by current models.

    “These models typically talk about much larger magnetic fields at the base of the jet, which many assume to be equivalent to the corona,” Dallilar told Newsweek.

    “Our results indicate that these models might be oversimplified. Specifically, there may not be a single magnetic field value for each black hole.”

    Black holes themselves don’t have magnetic poles, and therefore don’t generate magnetic fields. This means that the accretion disc corona magnetic fields are somehow generated by the space around a black hole – a process that is not well understood at this point.

    This result doesn’t mean that previous findings showing strong magnetic fields are incorrect, but it does suggest that the dynamics may be a little more complicated than previously thought.

    The team’s research did find that synchrotron processes dominated the cooling events, but could not provide data on what caused the particles to accelerate in the first place. It is, as one has come to expect from black holes, a finding that answers one question and turns up a lot more in need of further research.

    “We need to understand black holes in general,” said researcher Chris Packham of the University of Texas at San Antonio.

    “If we go back to the very earliest point in our universe, just after the big bang, there seems to have always been a strong correlation between black holes and galaxies. It seems that the birth and evolution of black holes and galaxies, our cosmic island, are intimately linked.

    “Our results are surprising and one that we’re still trying to puzzle out.”

    The research has been published in the journal Science.

    See the full article here .

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  • richardmitnick 11:10 am on December 22, 2017 Permalink | Reply
    Tags: , , Science Alert, , Where Did All That Mars Water Go? Scientists Have a New Idea   

    From U Oxford via Science Alert: “Where Did All That Mars Water Go? Scientists Have a New Idea” 

    U Oxford bloc

    Oxford University

    Science Alert

    21 DEC 2017
    DAVID NIELD

    1
    (Earth Observatory of Singapore/James Moore/Jon Wade)

    It’s still there… kind of.

    Billions of years ago, scientists think Mars was much warmer and wetter than it is now, so where did all that water go? New research published in Nature suggests much of it is actually locked inside the Martian rocks, which have soaked up the liquid water like a giant sponge.

    That teases an interesting addition to the commonly held hypothesis that the planet dried out as its atmosphere was stripped away by solar winds.

    Using computer modelling techniques and data we’ve collected on rocks here on Earth, the international team of scientists reckon that basalt rocks on Mars can hold up to 25 percent more water than the equivalent rocks on our own planet, and that could help explain where all the water disappeared to.

    “People have thought about this question for a long time, but never tested the theory of the water being absorbed as a result of simple rock reactions,” says lead researcher Jon Wade from the University of Oxford in the UK.

    Thanks to differences in temperature, pressure, and the chemical make-up of the rocks themselves, water on Mars could’ve been sucked up by the rocky surface while Earth kept its lakes and oceans, the researchers say.

    Martian rocks can also hold water down to a greater depth than the rocks on Earth can, according to the simulations.

    “The Earth’s current system of plate tectonics prevents drastic changes in surface water levels, with wet rocks efficiently dehydrating before they enter the Earth’s relatively dry mantle,” explains Wade.

    In the early days of the Earth and Mars, however, this wouldn’t have been the case, the researchers suggest. Volcanic lava layers would have changed the make-up of the rocks at the surface and could have made them more absorbent.

    “On Mars, water reacting with the freshly erupted lavas that form its basaltic crust, resulted in a sponge-like effect,” says Wade. “The planet’s water then reacted with the rocks to form a variety of water-bearing minerals.

    “This water-rock reaction changed the rock mineralogy and caused the planetary surface to dry and become inhospitable to life.”

    Even small differences in the iron content of the rocks on Earth and Mars, for example, can add up to significant changes in the way water gets sucked up, the research says. Plus, Mars is a much smaller planet, which would also have been a factor.

    The team agrees that solar winds are likely to have stripped away some of the water on Mars, but argues that much more of it could be locked away inside the Red Planet than previously thought – very handy once we get to set up base there.

    Experts also think Mars is hiding big reserves of water in the form of underground ice. But until we can take more readings and samples from the surface, it’s all just educated guesswork for the time being.

    Now the researchers want to use the same principles to study the possibility of finding water locked away in other planets, based on the composition of their rocks and tectonic activity – and where there’s water, there might be life.

    “When looking for life on other planets it is not just about having the right bulk chemistry, but also very subtle things like the way the planet is put together, which may have big effects on whether water stays on the surface,” says Wade.

    “These effects and their implications for other planets have not really been explored.”

    See the full article here.

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    U Oxford campus

    Oxford is a collegiate university, consisting of the central University and colleges. The central University is composed of academic departments and research centres, administrative departments, libraries and museums. The 38 colleges are self-governing and financially independent institutions, which are related to the central University in a federal system. There are also six permanent private halls, which were founded by different Christian denominations and which still retain their Christian character.

    The different roles of the colleges and the University have evolved over time.

     
  • richardmitnick 10:32 am on December 22, 2017 Permalink | Reply
    Tags: , , Physicists Overturn a 100-Year-Old Assumption on How Brains Work, , Science Alert, The human brain contains a little over 80-odd billion neurons each joining with other cells to create trillions of connections called synapses   

    From Science Alert: “Physicists Overturn a 100-Year-Old Assumption on How Brains Work” 

    ScienceAlert

    Science Alert

    22 DEC 2017
    MIKE MCRAE

    1
    (Kateryna Kon/Shutterstock)

    This is how neurons actually fire.

    The human brain contains a little over 80-odd billion neurons, each joining with other cells to create trillions of connections called synapses.

    The numbers are mind-boggling, but the way each individual nerve cell contributes to the brain’s functions is still an area of contention. A new study in Scientific Reports has overturned a hundred-year-old assumption on what exactly makes a neuron ‘fire’, posing new mechanisms behind certain neurological disorders.

    A team of physicists from Bar-Ilan University in Israel conducted experiments on rat neurons grown in a culture to determine exactly how a neuron responds to the signals it receives from other cells.

    To understand why this is important, we need to go back to 1907 when a French neuroscientist named Louis Lapicque proposed a model to describe how the voltage of a nerve cell’s membrane increases as a current is applied.

    Once reaching a certain threshold, the neuron reacts with a spike of activity, after which the membrane’s voltage resets.

    What this means is a neuron won’t send a message unless it collects a strong enough signal.

    Lapique’s equations weren’t the last word on the matter, not by far. But the basic principle of his integrate-and-fire model has remained relatively unchallenged in subsequent descriptions, today forming the foundation of most neuronal computational schemes.

    According to the researchers, the lengthy history of the idea has meant few have bothered to question whether it’s accurate.

    “We reached this conclusion using a new experimental setup, but in principle these results could have been discovered using technology that has existed since the 1980s,” says lead researcher Ido Kanter.

    “The belief that has been rooted in the scientific world for 100 years resulted in this delay of several decades.”

    The experiments approached the question from two angles – one exploring the nature of the activity spike based on exactly where the current was applied to a neuron, the other looking at the effect multiple inputs had on a nerve’s firing.

    Their results suggest the direction of a received signal can make all the difference in how a neuron responds.

    A weak signal from the left arriving with a weak signal from the right won’t combine to build a voltage that kicks off a spike of activity. But a single strong signal from a particular direction can result in a message.

    This potentially new way of describing what’s known as spatial summation could lead to a novel method of categorising neurons, one that sorts them based on how they compute incoming signals or how fine their resolution is, based on a particular direction.

    Better yet, it could even lead to discoveries that explain certain neurological disorders.

    It’s important not to throw out a century of wisdom on the topic on the back of a single study. The researchers also admit they’ve only looked at a type of nerve cell called pyramidal neurons, leaving plenty of room for future experiments.

    But fine-tuning our understanding of how individual units combine to produce complex behaviours could spread into other areas of research. With neural networks inspiring future computational technology, identifying any new talents in brain cells could have some rather interesting applications.

    See the full article here .

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  • richardmitnick 10:16 am on December 22, 2017 Permalink | Reply
    Tags: , Geologists Think They Finally Know Why Earthquakes Happen in The 'Wrong' Places, Science Alert, Tectonics   

    From Science Alert: “Geologists Think They Finally Know Why Earthquakes Happen in The ‘Wrong’ Places” 

    ScienceAlert

    Science Alert

    22 DEC 2017
    MIKE MCRAE

    1
    (CTVNews.ca, 2013)

    Somewhere in Eastern Tennessee the ground seems to quiver ever so gently, only to swiftly pass and leave those who felt it to question if it even happened. Seismologists record it, noting once again – far from the boundary of any tectonic plate – the soft rumble of an earthquake where none should be.

    Often quiet, occasionally devastating, these shakes are nearly always perplexing. Now geologists think they have some idea of what’s causing them, and the answer lies deep beneath our feet.

    As we learn in school, earthquakes are typically caused by the release of tension built up between the steady grind of Earth’s tectonic plates.

    But every year there are hundreds of tremors far from plate boundaries, known as ‘intraplate’ earthquakes. They don’t have an easy explanation, but geologists have recently identified a common characteristic of a number of such earthquake locations.

    The Canadian county of Charlevoix, US county of New Madrid, and the whole eastern third of Tennessee frequently experience earthquakes above a magnitude of 2.5, in spite of their distance from plate boundaries.

    They also share a similar geology far underground.

    “We present a new hypothesis that major seismic zones are restricted to places where the large-scale basement structures have been damaged by concentrated crustal deformation,” a pair of researchers from the University of Kentucky and the University of Memphis write in AGU Tectonics.

    This concentrated crustal deformation – or CCD – can include any activity that at some point in Earth’s history reduced the strength of the ancient rocky layers that make up the deepest parts of a continental crust.

    The researchers claim the basement structures beneath a number of the sites where frequent intraplate quakes occur are associated with ancient plate reorganisations.

    These scars would have been left hundreds of millions of years ago, only to have been reactivated over time.

    The Charlevoix Seismic Zone (CSZ) provides a perfect example. The area stretches 85 kilometres (53 miles) along the Saint Lawrence River in southeastern Quebec, and has experienced five earthquakes greater than magnitude 6 since 1663.

    Every year there are hundreds of microearthquakes, most too tiny to feel.

    Not only is the CSZ is located on a set of faults deep in its basement, it is the site of a significant meteor impact that struck close to 360 million years ago.

    The region’s earthquakes are mostly concentrated right where this collision occurred, with some rumbling up into the northeast for a short way along the faults.

    On their own, the impact features and the faults wouldn’t be expected to produce earthquakes, making it a geologically curious anomaly.

    Researchers have produced numerous models [AGU Tectonics] in an attempt to make sense of the area’s seismicity – whichever one they eventually settle on, it seems clear the deformation caused by the impact played a key role.

    The New Madrid Seismic Zone has a different story. This one’s deformations were the product of repeated massaging of the crust following the breakup of the supercontinent Rodinia over half a billion years ago.

    As for Eastern Tennessee, tension surrounding an abrupt kink within one of its deep faults resulted in something called a releasing bend – an extending of the crust along the fault that resulted in another kind of deformation.

    “Although the mechanisms producing the CCD vary, the regionally restricted CCD serves to focus seismicity in these three zones,” the researchers write.

    While necessary, these deformations might not be the only piece of the puzzle. Other stresses would be needed to turn a CCD into a seismic zone.

    As usual, more studies are called for to flesh out the idea and determine the exact nature of each crustal deformation.

    Given the challenges in predicting most earthquakes, though, knowing more about these peculiar hotspots is vital if we’re to arm ourselves against future activity.

    See the full article here .

    Please help promote STEM in your local schools.

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