Distant Star Dims Again, Revives Speculation of "Alien Megastructure"

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  Stars are fairly predictable. Our telescopes detect when they brighten and dim, and we usually have a plausible explanation why. Usually, it comes down to planets orbiting and temporarily blocking our line of sight.
 </p>
<p>
  But every now and then a star dims so erratically that neither amateur nor professional astronomers can make sense of it. That’s the case for KIC 8462852, or Boyajian’s star.
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/megastructure-1.width-990_ewKofyJ.jpg"/>
<figcaption>For years, astronomers have kept a watchful eye on KIC 8462852, hoping to observe and record its mysterious activity. This is an artist's illustration.
        
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<p>
  The star’s brightness has dimmed as much as 22% since it was first observed by the Kepler telescope several years ago. Astronomers haven’t observed this behavior on any other star before, so naturally it brings about many interesting theories. Here’s Delaney Chambers, writing for National Geographic:
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<p>
   Theories abound as to what’s going on. Among the most popular are that comets are passing in front of the star, or that a nearby planet has broken apart, blocking our view from Earth with fragments of planetary matter.
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<p>
   Some scientists theorize that the dimming could be due to an “alien megastructure” that’s orbiting Boyajian’s star and harvesting its energy.
  </p>
</blockquote>
<p>
  In the last month, Boyajian’s star dimmed not once but twice, first on April 24 and then again on May 19.
 </p>
<p>
  Scientists are maintaining their round-the-clock observations of this mysterious star to hopefully discover, once and for all, why it dims the way it does.
 </p>
<p>
  For more details,
  <a href="http://www.pbs.org/wgbh/nova/next/physics/bizarre-data-from-far-off-star-may-suggest-a-solar-collecting-megastructure/">
   read our earlier coverage on Boyajian’s star
  </a>
  .
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<p>
 Photo credit: NASA / JPL / CalTech
</p>

Bees Can Use Tools—And Train Other Bees to Use Them, Too

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  Bees are more flexible and adaptable than we realized.
 </p>
<p>
  A group of scientists at Queen Mary University of London trained bees to use a tool, a scenario they wouldn’t normally encounter in nature. Using a plastic bee on the end of a stick, biologist Olli J. Loukola showed bees how to move a tiny ball into the center of a platform to unlock a sugary treat. After five days of training, the bees started moving the ball to the center on their own.
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/bee-1.width-990_46xIwLk.jpg"/>
<figcaption>Bees were trained to move a ball to the center of a platform to unlock a sugary treat.
        
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<p>
  Loukola tried various training methods, including using a “ghost bee”—a magnet under the platform that would move the ball to the center and each proved successful. Bees that weren’t trained did not figure out how to get the treat. Then, he watched to see if the trained bees would show other untrained bees how to get the sugar water, which they did.
 </p>
<p>
  Yet, the bees were not just blindly imitating what they saw other insects do. When put in new kinds of situations, the trained bees adapted their behavior. Here’s Annalee Newitz reporting for Ars Technica:
 </p>
<blockquote>
<p>
   When offered a choice between three balls, the bees always chose to move the one that was closest to the center—even though they’d been trained in a situation where the two closest balls were glued down, and only the farthest ball could be moved. They also chose to use black balls, despite being trained on yellow ones. “The bees did not simply copy the behavior of the demonstrator but rather improved on the observed behavior by using a more optimal route,” Loukola and his colleagues wrote in a recent paper
   <a href="http://science.sciencemag.org/content/355/6327/833">
    in
    <em>
     Science
    </em>
</a>
   .
  </p>
</blockquote>
<p>
  This isn’t the first time the fuzzy critters have been put to the test. Previous experiments have shown they can count, tell each other where food is by using “waggle dances”, and pull strings to get access to food.
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  Learn more about the "waggle dance."
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  However, Loukola’s new tool test showed bees are not only good at using tools, they can also improvise to use them more effectively.
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  Watch the tool-using bees in action.
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</section>
<p>
 Photo credit:
 <a href="http://www.qmul.ac.uk/media/news/items/se/193087.html">
  Iida Loukola / Queen Mary University of London
 </a>
</p>

FDA Warns Tests for Lead Poisoning May Be Faulty

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  Pregnant or breast-feeding women and children younger than six years old should be retested for lead poisoning due to inaccurate test results, according to the Food and Drug Administration and the Centers for Disease Control and Prevention.
 </p>
<p>
  Magellan Diagnostics Inc. sells millions of tests, most of them are heel-stick or finger-stick tests. Yet the ones in question are tests for lead in blood taken from people’s veins. These tests may give results that are lower than the actual level of lead in the blood. The FDA believes this issue may be going back to 2014.
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/leadpipe.width-990_qXjAlVe.jpg"/>
<figcaption>The FDA and CDC are saying that some lead tests could be misleading, and might underestimate the amount of lead in people's blood.
        
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<p>
  Jeffrey Shuren, director of the FDA’s medical-device center believes most people will not be affected. But the agency still warns laboratories and health-care professions against using any Magellan Diagnostics lead tests with blood drawn from a vein. Here’s Patrick Breysse, director of the CDC’s National Center for Environmental Health in a press release:
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<blockquote>
<p>
   “While most children likely received an accurate test result, it is important to identify those whose exposure was missed, or underestimated, so that they can receive proper care. For this reason, because every child’s health is important, the CDC recommends that those at greatest risk be retested.”
  </p>
</blockquote>
<p>
  According to Breysse, fewer than 1% of the lead tests administered on the residents of Flint, Michigan—a city whose water system was tainted with lead—were the venous type. Don’t miss NOVA’s “Poisoned Water,” airing May 31, 2017, at 9/8c on PBS.
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 © WGBH Educational Foundation
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One of Iceland's Biggest Volcanoes May Be Poised for Eruption

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  One of Iceland’s most active volcanoes, Bárðarbunga, shook the earth four times in recent weeks, an indication it’s getting ready for eruption. Since part of it sits under an ice cap, an eruption could impact areas beyond the island.
 </p>
<p>
  The earthquakes—measuring magnitudes of 3.9, 3.2, 4.7, and 4.7—are an ominous sign—pressure in the magma chamber below the volcano is likely building to a breaking point. Geologists warn that the volcano is poised to erupt, though they don’t know when it will happen or how significant it will be.
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<figcaption>One of Iceland’s most active volcanoes experienced four large earthquakes, indicating it’s getting ready for eruption.
        
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<p>
  Despite Bárðarbunga’s remote location, the effects of its eruption could be felt well beyond Iceland. One-third of the system its a part of is covered by Europe’s largest ice cap, and volcanoes covered with ice can be highly explosive and produce lots of fine ash—which spews into the atmosphere and can affects larger areas. In 2010, when the Eyjafjallajökull volcano erupted, it threw ash miles into the atmosphere. For days, air travel throughout Europe ground to a halt—planes couldn’t risk flying through the engine-destroying ash cloud that stretched from Ireland to Russia.
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<p>
  Bárðarbunga poses similar risks. Here’s Elaina Zachos, reporting for National Geographic:
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<blockquote>
<p>
   Eruptions under ice can trigger explosions by turning large volumes of ice into steam, and as magma hits the steam it explodes into fine particles that can shoot high into the atmosphere. Or, lava from an eruption could melt the ice and cause flooding, like that brought on by the Eyjafjallajökull eruption.
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<p>
  Bárðarbunga’s most recent explosion was from August 2014 through February 2015, and it was the largest the country had seen in 200 years. Pollution—especially fine particulate matter that can be hazardous to breathe—blanketed western Europe.
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<p>
  Iceland’s residents aren’t strangers to volcanic eruptions. On average, a volcano in the system erupts once every 50 years.
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  Scientists hunt for a mega-eruption that plunged medieval Earth into a deep freeze.
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</section>
<p>
 Photo credit:
 <a href="https://commons.wikimedia.org/wiki/File:Bárðarbunga_Volcano,_September_4_2014_-_15146259395.jpg">
  peterhartree / Wikimedia Commons (CC BY-SA 2.0)
 </a>
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New Drug Could Bring Hope to Those At Risk For Huntington's Disease

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  In December 2017, a California company called Ionis released its preliminary results from a small Huntington’s disease study. These results have yet to be published or reported at medical meetings, but the findings so far are promising. They’ve developed a drug, called an antisense oligonucleotide, that reduced the production of an abnormal version of the huntingtin protein that could cause the disease.
 </p>
<p>
  Every four weeks for three months, 46 people from the United Kingdom, Germany, and Canada received an injection—of either the drug or a placebo—into their spinal fluid. Three to four months after their final dose, they returned to the lab for tests. The researchers then tallied up how much of the mutated huntingtin protein was present and found a reduced amount of protein in people who received the drug.
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/brain-cropped.width-990_BDqsvbR.jpg"/>
<figcaption>Wiring in the human brain
        
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  These results came as a surprise. While trials are often successful in Petri dishes or mice, it’s less common for human trials to be as promising. Here’s Esther Landhuis, reporting for Scientific American:
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<blockquote>
<p>
   Neuroscientist John Hardy, a University College London colleague not involved in the study, found the results a complete surprise. “It’s all very well to give antisense therapies to a mouse with a 300-milligram brain,” he says. “But to give spinal fluid injections [in people] and have it spread through the brain to an extent great enough to knock down gene expression….” He adds: “Three or four years ago, I would not have expected that to work, and yet it does. This could be a whole new generally applicable type of drug.”
  </p>
</blockquote>
<p>
  Huntington’s disease is a neurodegenerative disease—and like, Lou Gehrig’s, Parkinson’s, and Alzheimer’s, it has no cure. Symptoms like involuntary movement, slowness in speech or thinking, start appearing after a person’s 30
  <sup>
   th
  </sup>
  birthday. It’s an inheritable disease that can be traced to repetitions in a gene known as
  <em>
   HTT
  </em>
  . The brain cells convert this mutation into the protein that is thought to drive Huntington’s.
 </p>
<p>
  That’s where Ionis’s therapy comes in. Unlike other drugs, which target the symptoms, the company’s drug binds to RNA, which translates genes into proteins, and blocks the final set of instructions for making huntingtin.
 </p>
<p>
  While the results have been promising, there’s more work to be done before it becomes widely available. Researchers will need to conduct a larger trial, on the order of hundreds of patients, to see if lowering HTT slows the progression of Huntington’s disease. Then they would trial healthy people with the
  <em>
   HTT
  </em>
  mutation to see if antisense drugs could prevent it altogether.
 </p>
<p>
  This isn’t the first time an antisense drug has helped fight against disease. Two studies focusing on spinal muscular atrophy, an inherited neuromuscular disorder in children, were stopped in 2016 after kids taking the drug showed motor improvements so vast that it became unethical to keep giving other kids the placebo. Later that year, the U.S. Food and Drug Administration approved the drug.
 </p>
</section>
<p>
 Image credit:
 <a href="https://www.flickr.com/photos/wellcomeimages/25208604883">
  Wellcome Images / (CC BY 2.0)
 </a>
</p>

New Brain Imaging Tech May Give Doctors More Time to React to Strokes

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  In 2016, strokes killed more than 140,000 people in the U.S., making it the fifth-leading cause of death. The long-standing belief was that doctors only had six hours to save brain tissue, but a new study suggests they may actually have up to 16 hours.
 </p>
<p>
  During a stroke, a clot blocks a blood vessel, making it difficult for blood to flow to certain parts of the brain. Typically, doctors administer clot-dissolving medication within the first couple hours then remove what remains of the clot with devices like stents. The earlier a stroke is discovered and treated, the better chance the patient has of recovery.
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<figcaption>New research suggests doctors may have up to 16 hours to respond to strokes, which are caused by clots blocking blood flow in the brain.
        
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<p>
  The study involved 182 people from 38 medical centers in the United States. About half of them received the normal procedure of blood pressure medication, blood thinner, and other medical interventions. The other half received a new procedure as well as the usual medications. Fourteen percent of the people who had the new treatment died—and 45% avoided getting severe disabilities and were able to resume their independence—compared to 26% in the other group.
 </p>
<p>
  The procedure, called a thrombectomy, gives doctors more time to save brain tissue where the blood supply may have been cut off, but the tissue hasn’t died yet. The brain imaging technology, developed at Stanford University, uses a dye to show the damaged tissue surrounding dead tissue, allowing doctors up to 16 hours to remove the clot. Here’s Lenny Bernstein reporting for The Washington Post:
 </p>
<blockquote>
<p>
   “The big news is that we were all wrong in how we were thinking about how strokes evolve,” said Gregory W. Albers, a professor of neurology at Stanford University Medical Center and lead author of the new paper. While some brain tissue dies quickly after a stroke begins, in most patients, collateral blood vessels usually take over feeding a larger area of the brain that is also starved for blood and oxygen, giving doctors many more hours to save that tissue than they previously believed, Albers said.
  </p>
</blockquote>
<p>
  This would be useful for people who have strokes in their sleep because it’s often hard to pinpoint the exact time of the stroke or for people who live far from a medical center where they can undergo a clot-removing procedure.
 </p>
<p>
  Earlier this week, the American Heart Association/American Stroke Association released new treatment guidelines—the first in five years. They also included victims of mild strokes to the population of people eligible for clot-dissolving medication.
 </p>
</section>
<p>
 Photo credit:
 <a href="https://www.flickr.com/photos/liverpoolhls/10818486626">
  University of Liverpool Faculty of Health &amp; Life Sciences / Flickr (CC BY-SA 2.0)
 </a>
</p>

Scientists uncover a jawbone between 177,000 and 194,000 years old—making it the earliest modern human anyone has ever found outside of Africa.

Fossilized Jawbone Hints at a Much Earlier Exodus from Africa

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<p>
</p>
<p>
 Scientists digging in an Israeli cave uncovered a fossilized jawbone from what they believe is the earliest modern human found outside of Africa. The jawbone includes eight teeth—seven of which are intact. This changes the timeline of when
 <i>
  Homo sapiens
 </i>
 ventured out of Africa by about 50,000 years.
</p>
<p>
 Anthropologists previously believed that modern humans began leaving Africa 90,000 to 120,000 years ago. But the cave where the jawbone was discovered is thought to be occupied between 160,000 and 250,000 years ago. Israel Hershkovitz, a paleoanthropologist at Tel Aviv University, found the jawbone and suspected it was evidence of an earlier African exodus.
</p>
<p>
 To test that suspicion, Hershkovitz and his colleagues sent the jawbone on a world tour. First, it traveled to Austria where it underwent high resolution micro-CT scanning and then was compared with with 30 other specimens—which included Neanderthals,
 <i>
  Homo erectus
 </i>
 , and other
 <i>
  Homo sapiens
 </i>
 . In Australia, France, and Israel, they used dating techniques to determine the jawbone’s age.
</p>
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<p>
 Their results determined that the jawbone is between 177,000 and 194,000 years old—confirming the scientists’ hypothesis. Here’s Nicholas St. Fleur for The New York Times:
</p>
<blockquote>
<p>
 “We are now realizing that it was not one big exodus out of Africa in a given time period,” said Dr. Hershkovitz. “Rather, there was a flow of hominins coming in and out of Africa for at least the last half a million years.”
</p>
</blockquote>
<p>
 This is not the first time Hershkovitz has found modern human fossils. In 2010, he found 400,000-year-old teeth in Israel, and in 2015 he found a 55,000-year-old skull in the Israel.
</p>
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      Photo credit: Gerhard Weber/University of Vienna

<p>Scientists uncover a jawbone between 177,000 and 194,000 years old—making it the earliest modern human anyone has ever found outside of Africa.</p>

Ana Aceves

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