Scientists Take Global Warming's Temperature

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<p>
  By how many degrees would the average temperature of the Earth rise if carbon dioxide levels doubled? Scientists have been pursuing an accurate estimate of this figure since the late 19th century—it’s the “holy grail of climate science,” writes Justin Gillis in
  <em>
   The New York Times.
  </em>
  Most experts believe that this “climate sensitivity” figure lies somewhere just above five degrees Fahrenheit.
 </p>
<blockquote>
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   That may not sound like a particularly scary number to many people — after all, we experience temperature variations of 20 or 30 degrees in a single day. But as an average for the entire planet, five degrees is a huge number.
  </p>
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   The ocean, covering 70 percent of the surface, helps bring down the average, but the warming is expected to be higher over land, causing weather extremes like heat waves and torrential rains. And the poles will warm even more, so that the increase in the Arctic could exceed 10 or 15 degrees Fahrenheit. That could cause substantial melting of the polar ice sheets, ultimately flooding the world’s major coastal cities.
  </p>
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  Some recent studies, though, have proposed estimates below four degrees, stirring climate change skeptics and making some wonder if the future might look better than expected. But the well-regarded climate scientist James Annan warns against dismissing the threat of global warming. Gillis concludes:
 </p>
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   Even if climate sensitivity turns out to be on the low end of the range, total emissions may wind up being so excessive as to drive the earth toward dangerous temperature increases.
  </p>
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   So if the recent science stands up to critical examination, it could indeed turn into a ray of hope — but only if it is then followed by a broad new push to get the combustion of fossil fuels under control.
  </p>
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<p itemprop="articleBody">
  Alternatively, we might be able to put excessive carbon dioxide
  <a href="http://www.pbs.org/wgbh/nova/tech/carbon-sink.html" title="into storage.">
   into storage
  </a>
  .
 </p>
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Electric Shocks to Brain Could Improve Math Skills

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<p>
  Oxford University researchers found that students were better number-crunchers after a five-day course of brain stimulation. Here’s Ian Sample writing for Guardian Science:
 </p>
<blockquote>
<p>
   If future studies prove that it works – and is safe – the cheap and non-invasive procedure might be used routinely to boost the cognitive power of those who fall behind in maths, the scientists said. Researchers led by Roi Cohen Kadosh zapped students’ brains with a technique called transcranial random noise stimulation (TRNS) while they performed simple calculations, or tried to remember mathematical facts by rote learning.
  </p>
<p>
   In the study published in
   <a href="http://dx.doi.org/10.1016/j.cub.2013.04.045" title="">
    Current Biology
   </a>
   , 25 students had electrical pulses fired across their brains, while 26 others had a sham treatment, in which they thought they had brain stimulation, but the equipment was turned off.
  </p>
<p>
   In tests afterwards, the students who had their brains stimulated solved maths puzzles 27% faster than the control group, suggesting that their brains were working more efficiently.
  </p>
</blockquote>
<p>
  Some scientists doubt the claim’s validity, primarily because the study’s sample size was so small. Widespread implementation of this practice could also have ethical ramifications. Listen to this NOVA
  <a href="http://www.pbs.org/wgbh/nova/body/boost-kids-brainpower.html" title="radio story">
   radio story
  </a>
  (co-produced with PRI’s The World) to learn more.
 </p>
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How to Grow a Green Roof

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<p>
  Green rooftops aren’t just verdant escapes for urban dwellers. For the past two years, New York City
  <a href="http://www.nyc.gov/html/planyc2030/html/home/home.shtml" target="_blank">
   Mayor Michael Bloomberg’s PlaNYC initiative
  </a>
  has offered tax abatements for green roof construction projects, which help stabilize building temperatures and manage stormwater runoff. Many of these rooftops are populated with sedum, a plant that’s resilient to wind and UV rays, but, unfortunately, can sometimes make buildings hotter by absorbing heat rather than reflecting it. So what’s a good alternative? The answer might lie in the soil—not the plants themselves. Here’s Amy Kraft writing for Scientific American:
 </p>
<blockquote>
<p>
   Krista McGuire has taken sedum’s inadequacy as a challenge. The assistant professor of biological sciences at Barnard College wanted to see if a variety of native plants could survive on green roofs and how well they would deliver the desired benefits. Since 2010, the year Bloomberg announced his green roof initiative, McGuire has been comparing soil samples from 10 roofs planted with native vegetation with soil from five city parks spanning New York’s five boroughs, seeking to identify the microbial communities that thrive on green roofs to better to understand how healthy rooftop ecosystems sustain themselves.
  </p>
<p>
   Her study,
   <a href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0058020" target="_blank">
    published in
    <em>
     PLoS ONE
    </em>
</a>
   last April,
   <strong>
</strong>
   found that green roofs have distinct fungal communities that help plants to thrive in harsh, polluted environments and filter heavy metals. On average, 109 different types of fungi were present on each roof including
   <em>
    Pseudallescheria fimeti
   </em>
   , a fungus that grows in polluted soils and human-dominated environments. Rooftop soil also contained fungi from the genus
   <em>
    Peyronellaea,
   </em>
   which live in the tissues of plants to help them take in nutrients.
  </p>
</blockquote>
<p>
  Her study might be a step in right direction:
 </p>
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<p>
   “In the long term, this information may help individuals decide which types of soil microbes to amend on their green roofs, so that they can maximize plant survival and minimize management,” she says.
  </p>
</blockquote>
<p>
  This discovery is a variation on
  <a href="http://www.pbs.org/wgbh/nova/next/nature/fungal-network-helps-plants-communicate/" title="last week's">
   last week’s
  </a>
  ; a study published in Ecology Letters found that subterranean fungal networks help plants warn each other against impending aphid attacks.
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This Insect Jumps Using Built-In Gears

<p>
</p>
<p>
 Biomimicry—the use of nature to inspire design—is
 <a href="http://mentalfloss.com/article/22702/10-technologies-we-stole-animal-kingdom">
  widely used by cutting-edge technologists
 </a>
 to design everything from bullet train noses, new X-ray machines, and lighter and safer cars. But let’s take a moment to flip that idea on its head. Are there things we thought humans invented that have been later discovered in nature?
</p>
<div class="newsletter"></div>
<p>
 As a matter of fact, yes. Nymphs of a common insect found in Britain—
 <i>
  Issus coeleoptratus
 </i>
 , a species of planthopper—has what were presumably a very human creation—gears. While working at the University of Cambridge, Greg Sutton noticed a strange mechanism on the insect’s back legs. Here’s Adam Cole
 <a href="http://www.npr.org/2013/09/13/219739500/living-gears-help-this-bug-jump">
  reporting
 </a>
 for NPR’s Morning Edition:
</p>
<blockquote>
<p>
 There was a tiny row of bumps on the inside of each leg where it met the insect’s body. The bumps looked just like the teeth of gears. And when the planthopper jumped, they acted like gears too — as teeth meshed, the legs turned in synchrony. Sutton says his finding,
 <a href="http://www.sciencemag.org/content/341/6151/1254">
  published
 </a>
 this week in
 <i>
  Science
 </i>
 , is the first mechanical gear system ever observed in nature.
</p>
</blockquote>
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<p>
 The small bumps—called trochanters—are incredibly well suited to the planthopper, which springs away from danger in the blink of an eye. Sutton filmed the bugs hopping with a high-speed camera and noticed that both leaping legs moved almost simultaneously—the difference between the two was as short as 30 millionths of a second. That’s much shorter than the time it takes for a neuron to execute even the smallest, most rudimentary task. The synchrony propels the insect faster, farther, and straighter.
</p>
<p>
 Ed Yong,
 <a href="http://phenomena.nationalgeographic.com/2013/09/12/this-insect-has-gears-in-its-legs/">
  writing
 </a>
 for Not Exactly Rocket Science, has more background on Sutton’s research:
</p>
<blockquote>
<p>
 The planthopper nymphs lose them when they become adults. But the adults don’t shoot off in uncoordinated spins—if anything, they’re better jumpers than the youngsters. Their hind trochanters make much closer contact with each other, and Sutton thinks that
 <a href="http://www.ncbi.nlm.nih.gov/pubmed/20086132">
  the friction between them helps to keep them in time
 </a>
 . “We’re kind of sure about that, but not entirely sure,” he says.
</p>
</blockquote>
<p>
<i>
  Issus coeleoptratus
 </i>
 ‘s gears work similarly to their human-designed counterparts, but they have a leg up at smaller scales. Sutton—a mechanical engineer—thinks the trochanters could help us build more efficient machines:
</p>
<blockquote>
<p>
 Modern machines, such as 3-D printers, could easily create gears with these shark-fin teeth. Sutton is really excited by the prospect, and suspects that they may perform better in very small machines. “Modern machinery often doesn’t work at very small scales,” he says. “Friction doesn’t matter so much when you have two big gears next to each other but when you get small, friction starts killing you.”
</p>
</blockquote>
<p>
 The planthoppers might help to solve that problem. “We’re still being impressed and shocked by what we find in the back garden,” says Sutton.
</p>
<p>
<i>
  For more bioinspired technologies, watch “Making Stuff Wilder”, airing October 23 at 9/8 central on PBS.
 </i>
</p>
<div class="related"></div>
<p>
 Photo by Burrows/Sutton
</p>

<p>Are there things we thought humans invented that have been later discovered in nature?</p>

Some astrophysicists propose that the universe was formed by a collapsing 4D star.

Collapsing 4D Star Could Have Spawned Universe

<p>
</p>
<p>
 There could be a gaping hole in the Big Bang theory. Or rather, a giant, colossal black-hole caused by the collapse of a four-dimensional star.
</p>
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<blockquote>
<p>
 One of the main problems with the Big Bang is that the temperature of the universe is nearly uniform. If a “big bang” event
 <i>
  had
 </i>
 created the universe, then according to some explanations, there hasn’t been enough time between then and now for it to have reached that temperature equilibrium. Here’s Zeeya Merali writing for Nature News:
</p>
<p>
 To most cosmologists, the most plausible explanation for that uniformity is that, soon after the beginning of time, some unknown form of energy made the young Universe inflate at a rate that was faster than the speed of light. That way, a small patch with roughly uniform temperature would have stretched into the vast cosmos we see today.
</p>
</blockquote>
<div class="ad"></div>
<p>
 But the Big Bang, as it’s envisioned, was so chaotic that few people had any idea what or from where that initial homogenous patch could have come from.
</p>
<p>
 So Canadian astrophysicist Niayesh Afshordi and his colleagues have turned to an idea first proposed 13 years ago. In that model, our 3D universe is merely a membrane—also known as a brane—floating through a 4D “bulk universe":
</p>
<blockquote>
<p>
 Ashfordi’s team realized that if the bulk universe contained its own four-dimensional (4D) stars, some of them could collapse, forming 4D black holes in the same way that massive stars in our Universe do: they explode as supernovae, violently ejecting their outer layers, while their inner layers collapse into a black hole.
</p>
<p>
 In our Universe, a black hole is bounded by a spherical surface called an event horizon. Whereas in ordinary three-dimensional space it takes a two-dimensional object (a surface) to create a boundary inside a black hole, in the bulk universe the event horizon of a 4D black hole would be a 3D object — a shape called a hypersphere. When Afshordi’s team modelled the death of a 4D star, they found that the ejected material would form a 3D brane surrounding that 3D event horizon, and slowly expand.
</p>
</blockquote>
<p>
 Afshordi’s team believes that the universe—its stars, nebulae, planets, even us—might be that very membrane, and that its inflation might be triggered by motion through a “higher-dimensional reality.” In other words, we might be living in a brane around the event horizon of a collapsed hyperdimensional star that gave birth to the universe.
</p>
<p>
 It’s a bold claim—but one that solves a handful of problems in fundamental physics. Read Merali’s article for more details, and watch NOVA’s “Origins: Back to the Beginning” to learn more about other theories behind the creation of the universe:
</p>
<div class="newsletter"></div>
<p>
 Illustration by NASA
</p>

<p>We might be living in a brane around an event horizon of a collapsed hyperdimensional star that gave birth to the universe.</p>

3D Printed Soft Robots Could Ease Pain of Surgery

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<p>
  Surgery is a risky and brutal business. Even today’s most advanced medical technology—surgical robots—involves the touch of cold, unyielding metal to soft, delicate flesh. With all of those complications, surgery today can still be a precarious procedure. But soft robots
  <a href="http://www.gizmag.com/camouflage-robot-harvard/23749/" title="first created">
   first created
  </a>
  by Harvard University scientists might provide some relief.
 </p>
<p>
  The robots’ ability to maneuver through small spaces and
  <a href="http://www.youtube.com/watch?v=LpOl_pEmRqs" title="camouflage themselves">
   camouflage themselves
  </a>
  like
  <a href="http://www.pbs.org/wgbh/nova/nature/kings-of-camouflage.html" title="cuttlefish">
   cuttlefish
  </a>
  do initially caught the attention of the military. But now these squishy creations are being re-imagined as biomedical tools. Here’s Larry Greenemeier writing for Scientific American:
 </p>
<blockquote>
<p>
   Hard robots require a sophisticated feedback mechanism to help them determine how much force to apply during surgery so they do not damage our delicate tissues and organs. Soft robots could take advantage of their rubbery appendages to reduce the likelihood of surgical damage, says Carl Vause, CEO of Soft Robotics. “Specifically, with medical devices, [you would be] allowing a robotic instrument to get into a small space, be reconfigurable in that space and do it in a way that’s tissue compliant.” Another advantage: Soft robots can be 3-D printed in a day or two from silicone and other materials that cost about $20.
  </p>
</blockquote>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/soft-robot.width-990_wsY6yJA.jpg"/>
<figcaption>This glowing robot might also be the surgical tool of the future.
        
    </figcaption>
</figure>
<p>
  Robotic surgery has prompted
  <a href="http://well.blogs.nytimes.com/2013/09/09/new-concerns-on-robotic-surgeries/" title="some concern">
   some concern
  </a>
  in the recent past. The most well-known robot surgical system, known as da Vinci, is a $2 million endeavor that allows surgeons to manipulate laparoscopic instruments and an endoscopic camera attached to four robotic arms. But da Vinci significantly ups the cost of surgery and has also led to several lawsuits due to reports of sepsis, punctured blood vessels, and more.
 </p>
<blockquote>
<p>
   It will be some time before soft robots are capable of anything nearly as sophisticated as da Vinci, but there is a lot of interest in how this emerging technology could be used in the medical field—either on its own or combined with a surgical system like da Vinci.
  </p>
</blockquote>
<p>
  Experts are also interested in how soft robots could aid in prosthetics. Discover how scientists and engineers are
  <a href="http://www.pbs.org/wgbh/nova/next/tech/prospects-for-prostheses/">
   adding intelligence and flexibility into advanced prostheses
  </a>
  .
 </p>
<p>
  To learn more about one of the critters that inspired soft robots, watch “Kings of Camouflage” below and tune in to NOVA’s “
  <a href="http://www.pbs.org/wgbh/nova/tech/making-more-stuff.html#making-stuff-wilder" title="Making Stuff: Wilder">
   Making Stuff: Wilder
  </a>
  ,” airing October 23 at 9/8c on PBS.
 </p>
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</section>
<p>
 Photo courtesy
 <a href="http://www.darpa.mil/NewsEvents/Releases/2012/08/16a.aspx">
  DARPA
 </a>
</p>

How to Make a False Memory

<p></p><p><i>“Remembrance of things past is not necessarily the remembrance of things as they were.”</i> —Marcel Proust</p><p>Proust was on to something. As powerful as our memories may be, they’re certainly not infallible. Our minds lead us astray all the time, but experts hadn’t gotten to the root of the brain’s deceptiveness—until now.</p><p>Scientists at the Massachusetts Institute of Technology say they have successfully implanted a false memory in a mouse, giving insight into how memories—true and false—may form in the human brain. Led by Susumu Tonegawa (a Nobel laureate for his work in immunology), the team <a href="http://www.sciencemag.org/">reported Thursday in the journal Science</a> that they caused genetically modified mice to remember being shocked in a particular place when, in reality, that electric shock was delivered when the mouse was somewhere else entirely. Here’s <a href="http://www.technologyreview.com/news/517226/scientists-make-mice-remember-things-that-didnt-happen/">Susan Young, writing</a> for Technology Review:</p><p>Previously, the MIT-based team had <a href="http://www.ncbi.nlm.nih.gov/pubmed/22441246">shown</a> that it could pinpoint the location and assemblage of cells that carry a memory, and that activating those cells stimulated memory recall in mice. To create the new, false memory, Tonegawa’s team reactivated a mouse’s memory of a safe place while the animal received shocks in its feet, thus transforming the original memory.</p><p>First, the team used genetic tricks to label the brain cells involved in the memory of a chamber that was safe and neutral. The next day, they put the animal in a second chamber, a completely different setting. There, the animal got foot shocks while the researchers simultaneously shone light to reactivate the memory of the harmless first chamber. When the animal was put back in the first chamber, it fearfully froze—a clear indication that it remembered getting shocked in that chamber, even though that never happened.</p><p><a href="http://www.nytimes.com/2013/07/26/science/false-memory-planted-in-a-mouse-brain-study-shows.html">James Gorman wrote in The New York Times</a> that although mice and people are evolutionarily distant, the processes that govern memory formation in mammals are ancient. In both mice and men, memories form in an area of the hippocampus called the dentate gyrus—so conclusions drawn from this study are likely to apply to humans as well. Moreover, the scientists’ ability to locate and edit a memory is a significant achievement. Gorman quotes <a href="http://www.nytimes.com/2013/04/30/science/may-britt-and-edvard-moser-explore-the-brains-gps.html?pagewanted=all">Edvard I. Moser</a> , a neuroscientist at the Norwegian University of Science and Technology:</p><p>“What I find fascinating about this,” Dr. Moser said, “is that you actually can point to a physical substrate to memory,” what the researchers call an engram. Neuroscientists have long talked about engrams, but Dr. Moser said the recent research is the closest they have gotten to pointing to a spot in the brain and saying, “That is the memory.”</p><p>Of course, researchers have long known that memory blurs fact and fiction. But this new discovery is an important step toward figuring out how that actually works. <a href="http://www.guardian.co.uk/science/2013/jul/25/false-memory-implanted-mouse-brain">Writes Alok Jha</a> for <i>The Guardian</i> :</p><p>The mouse models created by the MIT team will help scientists ask ever more complex questions about memories in people. “Now that we can reactivate and change the contents of memories in the brain, we can begin asking questions that were once the realm of philosophy,” said Steve Ramirez, a colleague of Tonagawa’s at MIT.</p>

Allison Eck

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