Freshwater Aquifers & Brain Plasticity | SciByte 113

Posted on: December 17, 2013

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Freshwater Aquifers & Brain Plasticity | SciByte 113

We take a look at new sources of freshwater, plasticity, water on Europa, spacecraft updates, and as always take a peek back into history and up in the sky this week.

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Hidden Freshwater Reserves

  • According to the latest report documented in the journal Nature Australian scientists have identified vast freshwater reserves buried beneath the oceans
  • The Discovery
  • Groundwater scientists were very well aware of the presence of the freshwater reserves beneath the seafloor, but have assumed it to occur during unusual and extraordinary situations
  • Researchers have now revealed the presence of nearly half a million cubic kilometres [120,000 cubic mi] of low salinity water located beneath the seabed on the continental shelves
  • Located off Australia, China, North America and South Africa, the newly discovered fresh water reserves can be used to supply water to coastal cities
  • This water resource is a hundred times greater than the amount we\’ve extracted from the Earth\’s subsurface in the past century since 1900
  • This latest study reveals that the fresh and brackish aquifers under the seabed are a common phenomena
  • Formation
  • Hundreds to thousands of years ago when the sea level was lower than what it is currently rainwater penetrated into the ground and filled up the water tables in regions that are currently under sea
  • Nearly 20,000 years ago, the sea levels rose, the ice caps began melting and the areas were covered by oceans
  • Most of the aquifers today are protected from seawater by blankets of clay and sediments that are piled on top
  • These aquifers are not different from those found below land. Their salinity is low due to which they can be easily converted into drinking water
  • Acquisition and Use
  • Researchers propose two ways to gain access to these freshwater reserves, either be by constructing a platform and drilling into the seabed, which is expensive, or drill from the mainland that is at a closer distance from the aquifer
  • Freshwater under the seabed is much less salty than seawater and it can be converted to drinking water with less energy than seawater desalination and also leave us with a lot less hyper-saline water
  • Because of how they formed, these water reserves are non-renewable and should be used carefully
  • Further Reading / In the News
  • Scientists Discover Untapped Freshwater Reserves Beneath the Oceans | ScienceWorldReport.com

— NEWS BYTE —

Learning New Skills

  • A new computational model developed by MIT neuroscientists explains how the brain maintains the balance between plasticity and stability and how it can learn very similar tasks without interference between them.
  • To learn new motor skills, the brain must be plastic: able to rapidly change the strengths of connections between neurons, forming new patterns that accomplish a particular task, if the brain were too plastic, previously learned skills would be lost too easily.
  • Neurons
  • The key is that neurons are constantly changing their connections with other neurons
  • Not all of the changes are functionally relevant – they simply allow the brain to explore many possible ways to execute a certain skill, such as a new tennis stroke
  • The brain is always trying to find the configurations that balance everything so you can do two tasks, or three tasks, or however many you\’re learning
  • According to this theory as the brain explores different solutions, neurons can become specialized for specific tasks
  • As the brain learns a new motor skill, neurons form circuits that can produce the desired output
  • Modifications
  • Perfection is usually not achieved on the first try, so feedback from each effort helps the brain to find better solutions, complications arise when the brain is trying to learn many different skills at once
  • Because the same distributed network controls related motor tasks, new modifications to existing patterns can interfere with previously learned skills, particularly when you\’re learning very similar things such as two different tennis strokes
  • Instructions for each task would be stored in a different location on a computer chip; however, the brain is not organized like a computer chip.
  • Instead, it is massively parallel and highly connected – each neuron connects to, on average, about 10,000 other neurons
  • That connectivity offers an advantage, however, because it allows the brain to test out so many possible solutions to achieve combinations of tasks
  • The constant changes in these connections, which researchers call hyperplasticity, is balanced by another inherent trait
  • Neurons have a very low signal to noise ratio, meaning that they receive about as much useless information as useful input from their neighbors
  • New Model with Signal Noise
  • Most models of neural activity don\’t include noise, but the MIT team says noise is a critical element of the brain\’s learning ability
  • This model helps to explain how the brain can learn new things without unlearning previously acquired skills
  • The paper shows is that, counterintuitively, if you have neural networks and they have a high level of random noise, that actually helps instead of hindering the stability problem
  • Without noise, the brain\’s hyperplasticity would overwrite existing memories too easily
  • Low plasticity would not allow any new skills to be learned, because the tiny changes in connectivity would be drowned out by all of the inherent noise
  • What it Means
  • The constantly changing connections explain why skills can be forgotten unless they are practiced often, especially if they overlap with other routinely performed tasks
  • Skills such as riding a bicycle, which is not very similar to other common skills, are retained more easily
  • Once you\’ve learned something, if it doesn\’t overlap or intersect with other skills, you will forget it but so slowly that it\’s essentially permanent
  • Researchers are now investigating whether this type of model could also explain how the brain forms memories of events, as well as motor skills
  • Multimedia
  • YouTube | How Neurons Work Made Simple ~ An Animated Guide | cosmiccontinuum
  • Further Reading / In the News
  • How Our Brain Balances Old and New Skills | ScienceWorldReport.com

— TWO-BYTE NEWS —

MarsOne, Another Step Forward

— VIEWER FEEDBACK —

Water Jets Above Another One of Jupiters Moons

  • Jacob F. Roecker ‏@jacobroecker
  • Check This Out
  • NASA\’s Hubble Space Telescope has spotted water vapor above Europa frigid south polar region, providing the first strong evidence of water plumes erupting off the moon\’s surface
  • Only after a particular camera on the Hubble Space Telescope had been repaired on the last servicing mission by the Space Shuttle did we gain the sensitivity to really search for these plumes
  • Europa’s ocean could help explain its jigsaw surface | Arstechnica.com
  • Water Plumes
  • Scientists had previously detected evidence of an ocean under Europa\’s icy crust
  • The simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa
  • If those plumes are connected with the subsurface water ocean then future investigations can directly investigate the chemical makeup of Europa\’s potentially habitable environment without drilling through layers of ice
  • Water Plumes Seen Before
  • This would actually be the second moon in the solar system known to have water vapor plumes, the first one to be discovered was Saturn\’s moon Enceladus
  • First detected in 2005 by NASA\’s Cassini orbiter, the plumes of Enceladus possess dust and ice particles
  • Surface Terrain
    • Jupiter’s icy moon Europa has cracks in its surface, as seen before on Enceladus
  • On Europa the cracks come in the form of jumbled pieces of ice that make up what are called the moon\’s “chaos terrains.”
  • It seems likely that the ocean has something to do with the chaos terrain, especially given the presence of salt there
  • To figure that out, however, we’d have to know something about how water circulates in that ocean
  • It’s been thought that the big-picture pattern might look something like the atmosphere of Jupiter, with alternating bands of eastward or westward flow.
  • Circulation in the ocean would be driven by the heat from Europa’s interior, making it difficulty of studying Europa’s oceans
  • When They Can Be Seen
  • Europa plumes are similar to Enceladus in that they also seem to vary depending on the moon\’s orbital position; active jets have only been seen when Europa is farthest from Jupiter
  • This supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean
  • The Future
  • Once the plumes are confirmed, scientists can take a closer look at their composition and may even be able to find out more about the potential subsurface sea of Europa
  • Future space probe missions to Europa could confirm that the exact locations and sizes of vents and determine whether they connect to liquid subsurface reservoirs
  • ESA\’s JUpiter ICy moons Explorer, a mission planned for launch in 2022, and which aims to explore both Jupiter and three of its largest moons: Ganymede, Callisto, and Europa.
  • Multimedia
  • YouTube | Jupiter Moon Europa\’s Water Plume Spied By Hubble – Artist Impression Video | VideoFromSpace
  • Further Reading / In the News
  • New computer model may explain moon Europa\’s chaotic terrain | Phys.org
  • Hubble discovers water vapor venting from Jupiter\’s moon Europa | Phys.org
  • NASA Hubble Telescope Discovers Water Plumes Over Icy Europa | ScienceWorldReport.com
  • Europa\’s ocean could help explain its jigsaw surface | Ars Technica

— SPACECRAFT UPDATE—

International Space Station Troubles

China’s Chang’e-3 Moon Rover

SCIENCE CALENDAR

Looking back

  • Dec 22, 1882 : 131 years ago : Christmas Tree Lights : The first string of electric lights decorating a Christmas tree was created for his home by Edward H. Johnson, an associate of Thomas Edison. Previously, trees had been decorated with wax candles. The Dec 1901 issue of the Ladies\’ Home Journal advertised the Christmas tree lamps, first made commercially by the Edison General Electric Co. of Harrison, N.J. in strings of nine sockets, each with a miniature 2 candlepower, 32-volt, carbon-filament lamp*. Christmas tree lights quickly became the rage among wealthy Americans, but the average citizen didn\’t use them until the 1920s or later. Character light bulbs became popular in the 1920s, bubble lights in the 1940s, twinkle bulbs in the 1950s and plastic bulbs by 1955.
  • The First Electric Christmas Tree Lights | TodayInSci.com

Looking up this week

  • Keep an eye out for …
  • Sat, Dec 21 | The shortest day of the year in the N hemisphere and the longest day in the S hemisphere. Winter officially begins in the N hemisphere at the solstice at 12:11pm EST
  • Winter Constellation | Orion | Is in the E-SE right now, when it rises its three belt start are nearly verticle Image
  • Planets
  • Venus | \”Evening Star\” | Rises in the SW during and after dusk moving lower and lower each day
  • Mars | Rises around 12-1 am local, and moves to the high S skies by dawn
  • Jupiter | End of Twilight | Rises in the E-NE, and rises to its highest point around 1-2am. The moon will be near Jupiter off and on for now, interesting to know that Jupiter is 1,600 times farther away than the Moon.
  • Saturn | Dawn Brightening | Rises in the SE, it is far to the lower left of Mars

SciByte is going on a Holiday break, we will be Back Jan 7, 2014 See you then!

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