RealClearScience Journal Club

Science Figures Interpreted and Analyzed by RealClearScience

Scientists See Signs of Learning in a Ball of Dough

Ross Pomeroy - October 24, 2016

Humans can learn. Animals can learn. Plants can learn. So why can't a ball of dough learn, too? A new study published in PLoS ONE suggests that it can.

Inspired by a now obscure 1955 paper showing that iron bars could be conditioned to respond to electromagnetic fields, researchers Nicolas Rouleau, Lukasz Karbowski, and Michael Persinger of Laurentian University sought to see if they could train an electroconductive material to respond to pulsed light from an LED by pairing the light with electric shocks.

"Electroconductive material" is a fancy term for what the researchers described as "effectively a dough." Composed of 237 cubic centimeters (cc) of water, 355 cc of flour, 133 cc of lemon juice, 59 cc of table salt, 15 cc of vegetable oil, and 2cc of food coloring, the substance could easily be repurposed as a pie crust if you toss in a little sugar.

Rouleau and his colleagues formed the substance into numerous blobs and hooked them to a jumper cable and various measuring devices (see above image). A red LED was positioned nearby. With this set-up, they repeatedly exposed the dough to electric shocks paired with flashes of the LED light. In some trials, the shock and LED flash were simultaneous, and in others, the flash was delayed by up to 500 milliseconds.

After training, and following a one or five-minute delay, they exposed the conditioned dough to a flash of the LED and observed its spectral power density. When the dough was presented with the LED light, it produced electrical activity to when it was shocked. Untrained dough did not show the response.

"Only when the dough had a history of being shocked when presented with the light did it express electrical activity with a spectral profile which overlapped with the shock profile," Rouleau explained via email.

"The fact that the 'conditioned' group displayed a power spectral density that was most similar to the power spectral density elicited by electric current only is consistent with learning," he and his authors write.

Interestingly, the dough successfully "learned" the response when the flash and shock were paired within 130ms of each other. Any longer, and the response went unlearned. This mirrors what researchers observe with animals, Rouleau says. When stimuli are not paired closely enough in time, animals won't learn the desired behavior.

Examining the dough under a microscope, the researchers saw physical evidence of how the dough was able to "learn." Dough exposed to both the shock and the light had a distinct structure compared to dough that went unexposed, was exposed the light only, was exposed to the shock only, or was crushed and recycled following the trials.

"The histology data are what convinced us. We observed greater complexity... in the 'conditioned' samples," Rouleau told RCS.

"In summary, the data indicate that a conditioned response can be encoded into a simple material, that the conditioned response is associated with structural modifications within the substrate," the researchers conclude.

The results indicate that learning may be a far more fundamental process than previously thought.

Citation: Rouleau N, Karbowski LM, Persinger MA (2016) Experimental Evidence of Classical Conditioning and Microscopic Engrams in an Electroconductive Material. PLoS ONE 11(10): e0165269. doi:10.1371/journal.pone.0165269

Silver Erupts Like a Volcano at the Nanoscale

Ross Pomeroy - October 10, 2016

A team of Japanese and Taiwanese researchers has observed silver erupting like a volcano at the nanoscale. Announced in the journal Scientific Reports, the finding opens the door to new applications of the element.

The discovery is comparable to teaching an old dog an entirely new trick. Humans have been coveting and working with silver for thousands of years. Ancient Greeks and Turks mined the lustrous, malleable metal as early as 3000 BC to use it for coins, silverware, and jewelry. Silver's impressive thermal and electrical conductivity means that it's predominantly used in electronic devices today. The present finding will likely expand the metal's usage in that frontier.

The researchers blended oxygen atoms into liquid and poked and prodded the mixture at various temperatures and pressures until they witnessed a surprising series of events (illustrated in the figure below):

The Ag-O liquids that are ejected from grain boundaries are transformed into oxygen gas and free silver and siiver-oxide clusters, exactly as in a volcanic eruption. The suspended silver and silver-oxide clusters are then re-deposited on the silver film, just as ash falls after a volcanic eruption, forming a conformal Ag-O coating.

The team quickly learned to control the process with remarkable precision, utilizing it to spell the names of their institutions (Osaka University and National Cheng Kung University) at the microscale.

Silver is one of the most important metals in the history of civilization, the researchers note. For as long as we've been using it, the present finding makes it clear that we have so much more to learn.

Source: Lin, S.-k. et al. Nano-volcanic Eruption of Silver. Sci. Rep. 6, 34769; doi: 10.1038/srep34769 (2016).

(Top Image: siloo)

A Strange "Cold Earth" Spot in China Stays Frozen Through Scorching Summers

Ross Pomeroy - October 5, 2016

In summer 2011, residents of Pingquan County in Northern China were surprised to stumble upon frigid ground when hiking up a gentle mountain slope. Despite a meager elevation of just 900 meters and hot air temperatures exceeding eighty degrees, the earth was frozen solid! Their bewildering discovery quickly caught the attention of researchers at the Chinese Academy of Sciences, who set out to study the climate-defying soil. They just reported their assessment of the site in the journal Scientific Reports after four years worth of observations.

What they found was a tidy collection of permafrost just beneath the top soil, roughly eighty meters long, twenty meters wide, and ten meters tall (see figure below). Permafrost, ground that remains at or below zero degrees Celsius for at least two consecutive years, is quite common, underlying roughly a quarter of Earth's surface. But in Pingquan County, where summer temperatures can climb into the nineties, permafrost really shouldn't exist.

Sixteen other anomalous areas of low ground temperature have been identified on Earth, but what sets the newfound cold spot (L-15 in the figure below) apart from the rest is its location. The site is more than 600 kilometers south of the southernmost limit of permafrost on the Eurasian Continent, the researchers say. The only other anomalous cold earth in the Northern hemisphere that's farther south rests atop the Qinghai-Tibet Plateau at an elevation of 4,700 meters.

The researchers attribute the permafrost's existence to the site's unique composition. A course, blocky layer of soil is sandwiched between a layer of clay below and an insulating layer of peaty soil above.

When air temperature drops sharply in mid-November, the cold, dense air penetrates rapidly into the voids between the blocks, resulting in a near-heterogeneous temperature distribution in the blocky layer from top to bottom due to air convection within the porous material. During the early thaw period... there is no convective heat transfer between the warmer (lighter) air above and the colder (denser) air below. Such a thermal regime indicates the heat exchange between the coarse blocky layer and the ambient environment is relatively instantaneous and intense in winter, while prolonged and feeble in summer.

Source: Niu, F. et al. A naturally-occurring ‘cold earth’ spot in Northern China. Sci. Rep. 6, 34184; doi: 10.1038/srep34184 (2016)

Got Low T? Testosterone Drugs Probably Won't Help

Ross Pomeroy - September 22, 2016

In 2002, Solvay Pharmaceuticals, maker of the testosterone supplement AndroGel, launched a global marketing campaign to pathologize male aging. The gradual and natural decrease in testosterone that all men face was no longer inevitable. Instead, it was a treatable condition called "Low T". The "Testosterone Crisis" was born, and sales skyrocketed.

But while branding can conceal the truth; it cannot change it. The companies behind testosterone supplements like AndroGel, Axiron, and Testim hint that their products can improve mood, boost cognitive function, treat erectile dysfunction, and alleviate depression. The weight of scientific evidence says otherwise.

A new systematic review primarily carried out by researchers at Georgetown University neatly summarizes the available data.

"The prescription of testosterone supplementation for low-T for cardiovascular health, sexual function, physical function, mood, or cognitive function is without support from randomized clinical trials," the reviewers reported in the journal PLoS ONE.

The authors evaluated 156 randomized controlled trials in which testosterone was compared to placebo to treat a variety of conditions. Testosterone did not consistently prevent or treat cardiovascular disease, nor did it consistently improve sexual function or satisfaction, with half of the studies showing positive effects and the other half not showing any effects. It was altogether ineffective at treating erectile dysfunction. The majority of studies showed no effects on psychological well-being or cognitive function.

Testosterone did offer a few benefits. The review indicated a small boost to libido and a robust increase in muscle mass. However, the increase in mass was not accompanied by increases to strength.

As of 2013, roughly 2.2 million American men were taking prescription testosterone. For some, affected by genuine hypogonadism, a condition where the testes do not produce enough testosterone, supplementing the hormone may be called for. But for otherwise healthy men simply undergoing normal aging, testosterone probably won't have much effect. Simpler remedies like exercising and maintaining a healthy weight may provide more of a benefit, the reviewers suggest.

Source: Huo S, Scialli AR, McGarvey S, Hill E, Tügertimur B, Hogenmiller A, et al. (2016) Treatment of Men for “Low Testosterone”: A Systematic Review. PLoS ONE 11(9): e0162480. doi:10.1371/journal.pone.0162480

How Does the Ocean Sunfish Get So Big?

Ross Pomeroy - September 12, 2016

The ocean sunfish (Mola mola) has a radiant name, but its appearance doesn't exactly match its glowing moniker. Wrinkled and colored a sickly shade of gray, the sunfish doesn't exactly shimmer. However, its pallor isn't nearly as distracting as its awkward shape -- the fish is usually taller than it is long. Moreover, the sunfish's mouth is constantly agape, granting it a dumbfounded look of everlasting surprise. With that gaping maw, the sunfish primarily consumes jellies, a less-than-sumptuous prey. Yet it is on this slimy diet that sunfish can attain weights of over 1,000 kilograms and lengths of nearly six feet. The largest sunfish weighed in at 2,300 kilograms and extended over ten feet in length! Not bad for a fish that, as a baby, begins life measuring just four millimeters across.

The ocean sunfish's immense size has earned it the title of "world's largest bony fish." As you might imagine, getting that bulky takes some serious growing. Researchers recorded a captive sunfish ballooning 880 pounds in fifteen months, an average of 1.8 pounds per day. That's far, far above other ray-finned fish, even ones that are similar in size to the sunfish.

Recently, researchers published the first genome sequence of the ocean sunfish. The results rendered insights into the fish's incredible growth rate.

"Several sunfish genes involved in the growth hormone and insulin-like growth factor 1 axis signalling pathway were found to be under positive selection or accelerated evolution, which might explain its fast growth rate and large body size," the researchers noted. 

Indeed insulin-like growth factor 1 (IGF-1) is one of the primary growth hormones in humans, as well. People insensitive to or deficient in the hormone experience stunted growth or dwarfism. The ocean sunfish, on the other hand, seems to produce a boatload of the stuff. This means that with plenty of food, the charismatic fish can grow and grow and grow.

Source: Hailin Pan et. al. "The genome of the largest bony fish, ocean sunfish (Mola mola), provides insights into its fast growth rate." GigaScience 9 Sept 2016 5:36  DOI: 10.1186/s13742-016-0144-3

(Images: Per-Ola Norman , G. David Johnson)

A Simple Phone Game Could Diagnose Autism

Ross Pomeroy - August 25, 2016

Roughly one out of every 68 children in North America has autism spectrum disorder (ASD), a developmental condition broadly characterized by difficulties in social interaction, problems with communication, and repetitive behaviors.

Every ASD diagnosis is a complicated, involved process. The child -- who is often between the ages of two and six -- undergoes a battery of behavioral evaluations overseen by trained professionals, usually in a clinical setting. He or she is observed and tested, sometimes for lengthy periods. Diagnoses can be equally extended.

But researchers from Jagiellonian University in Poland and the University of Strathclyde in the United Kingdom have a plan to streamline the process. They aim to diagnose autism with a simple game played on a phone or tablet. In a recent study published to the journal Scientific Reports, they took a significant stride towards reaching that goal.

Prior research has hinted that children diagnosed with ASD demonstrate distinct patterns in motor control, particularly with their hands. With this in mind, authors Anna Anzulewicz, Krzysztof Sobota, and Jonathan T. Delafield-Butt recruited 37 children between the ages of three and six years old and matched them with 45 typically-developing controls of equal age at the same gender ratio. One-by-one, each child was brought into a room, sat in front of an iPad mini affixed to a table, and instructed to play two basic games for seven minutes each. The duration was split into two minutes of training followed by five minutes of solo play. (Figure below: One game involved sharing a piece of fruit between four characters. The other game involved tracing and coloring different objects.)

In those short and painless moments, the researchers collected heaps of data on the children's finger movements extracted via inertial sensors and the tablet's touchscreen. Machine-learning algorithms subsequently examined the data to determine precise motor patterns associated with ASD. Children with autism touched the screen with more impact force and greater pressure compared to controls. They also swiped faster and tapped the screen more quickly.

Utilizing those touch patterns, the algorithm devised diagnostic criteria for autism based on the children's gameplay. The criteria successfully identified the autistic children with an impressive 93 percent accuracy. The researchers were elated with the results.

"We have shown here that smart tablet technology offers an attractive, new paradigm for clinical autism assessment... enabling engaging, ecological testing of children’s motor behaviour in a fun, accessible format..." they write.

The study is an exciting proof-of-concept, the researchers say, but more work needs to be done. Next, they aim to test their approach on many more subjects in order to refine the algorithm's diagnostic criteria and eliminate potential confounding variables.

Source: Anzulewicz, A. et al. Toward the Autism Motor Signature: Gesture patterns during smart tablet gameplay identify children with autism. Sci. Rep. 6, 31107; doi: 10.1038/srep31107 (2016).

A Lethal Plague Ravaged Florida Corals in 2014

Ross Pomeroy - August 15, 2016

Life's been hard for coral of late. Scarcely a week goes by without dire news for the charismatic ocean invertebrates.

Take the coral depicted above, for example. The first picture, taken August 20th, 2014, shows a healthy colony going about its business just off Florida's Virginia Key. Only a month later (picture B), the coral was left bleached and vulnerable as high water temperatures forced symbiotic algae to vacate. These symbionts, called zooxanthellae, returned roughly six weeks later when temperatures dropped, but by then, the coral colony was imperiled by a new, far more dangerous threat: white plague. You can see its first traces on the colony's lower right side in picture C. Less than a month later (picture D), the coral was dead and buried by sea sediments.

This story was all too common within Florida's coral reefs between September 2014 and September 2015. During that time, an unprecedented and highly lethal outbreak of white plague struck corals situated off Miami-Dade County. Researchers just revealed the extent of the outbreak in the journal Scientific Reports.

White plague deserves any and all comparisons to the bubonic plague that fueled Europe's Black Death from 1346 to 1353. Once a coral is infected, the disease spreads rapidly. Small lesions or blemishes at the base or surface of the colony quickly blossom into an expanding ring of necrotic tissue. A small colony can be engulfed in less than a week, with only a bare, white skeleton left behind.

The variety of white plague that struck off Florida in 2014 and 2015 was likely caused by a bacterium. Another version -- there are two total -- might be viral in origin.

The researchers surveyed a total of 14 sites all along the coast of Miami-Dade County and found that 61% of coral species were infected. Moreover, virtually all infected coral colonies died. That prevalence is unprecedented, the researchers say. Also remarkable is the fact that most of the colonies were spread over a wide area of more than 130 kilometers with limited coral cover, indicating that this strain of white plague could travel in water and was highly contagious.

Eight species of coral were particularly devastated by the outbreak. The figure below shows the number of colonies surveyed (n) and the proportion infected.

The researchers believe that a prior temperature-induced coral bleaching event greatly enhanced the severity of the outbreak, and further suggest that as climate change raises ocean temperatures, coral disease outbreaks will grow more common, more widespread, and more deadly. What occurred in Florida between September 2014 and September 2015 is merely a preview.

"The high prevalence of disease, the number of susceptible species, and the high mortality of corals affected suggests this disease outbreak is arguably one of the most lethal ever recorded on a contemporary coral reef," the researchers say.

Source: Precht, W. F. et al. Unprecedented Disease-Related Coral Mortality in Southeastern Florida. Sci. Rep. 6, 31374; doi: 10.1038/srep31374 (2016).

Greenland Sharks Live 400 Years or More, Making Them the Longest-Lived Vertebrates

Ross Pomeroy - August 11, 2016

In the 1620s, the Mayflower pilgrims landed in what is now Massachusetts, the Thirty Years War raged in Central Europe, Johannes Kepler put forth his laws of planetary motion, and the oldest-known Greenland shark was born.

While the Pilgrims, the Thirty Years War, and Johannes Kepler are enshrined in history books, the realization about the Greenland shark was just made public today in the journal Science.

To uncover the result, Julius Nielsen, a PhD student at the University of Copenhagen, along with an international team of researchers, used radiocarbon dating on the eye lens nuclei of 28 female Greenland Sharks captured between 2010 and 2013.

Crystalline proteins within the eye are formed around the time an animal is born and remain essentially unchanged for life. These proteins contain a fixed amount of Carbon-14, a radioactive isotope of Carbon that decays at a known rate. For the last few hundred years before 1960, when nuclear bomb tests doubled the amount of Carbon-14 in the atmosphere, that level remained relatively consistent. Thus, Nielsen and his colleagues measured the levels of Carbon-14 in the sharks' eye lenses and extrapolated back based on the rate of decay to determine the animals' ages.

The largest shark was determined to be 392 years old, give or take 120 years. Based on the results, the researchers also estimated that the animals might not reach sexual maturity until age 156! (Below: The graph shows the estimated birthdate for each shark. Length (TL) is on the Y-axis. Every blue "hump" corresponds to one shark and covers the range of potential birthdates.)

Greenland sharks live in the frigid waters of the North Atlantic and Arctic Oceans where they mostly feed on fish. Swimming no more than two miles per hour, the hulking beasts move slowly and grow just as slowly, just 0.5 to 1 centimeters per year. Yet they can grow to be more than six or even seven meters in length! This means there are likely even older Greenland sharks out there waiting to be aged.

"Our results show that the Greenland shark is the longest-lived vertebrate known," the researchers write. With the finding, the Greenland shark firmly passes the bowhead whale, which is estimated to live up to 211 years.

Source: Nielsen et. al. "Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)." Science. 12 AUGUST 2016 • VOL 353 ISSUE 6300. DOI: 10.1126/science.aaf3617

(Image: NOAA Okeanos Explorer Program)

A New Description of Our Last Universal Ancestor

Ross Pomeroy - July 25, 2016

Meet LUCA.

LUCA is, or rather was, a single-celled organism that lived in an oxygen-free hot spring. Its enzymes were packed with iron along with traces of other transition metals, hinting that LUCA's watery home was also rich in these metals. Within this cozy, metallic habitat, it fed on hydrogen and absorbed carbon dioxide and nitrogen from its surroundings, converting them to organic compounds in the proces. In many respects, LUCA was very similar to modern-day extremophiles dwelling near hydrothermal vents in the deep ocean.

Why should you care about LUCA? Because -- in a sense -- LUCA was your great, great, great, great, great, great (etc.) grandparent; the Last Universal Common Ancestor of all life on Earth. Between 3.5 and 3.8 billion years old! Respect your elders. (Figure Below: LUCA is the black line at the bottom.)

LUCA was just described in new detail in the journal Nature Microbiology. Madeline Weiss and Filipa Sousa led a team based out of Heinrich Heine University Düsseldorf in Germany. Together, they compiled gene families that exist in at least two species of Bacteria and two species of Archaea (Bacteria and Archaea being the most basic forms of life on Earth) and arranged them into phylogenetic trees. 286,514 gene families made the cut. Examining the trees, the researchers found that only 355 gene families descended from a common evolutionary ancestor and weren't shared with any other group.

"These 355 proteins were probably present in LUCA and thus provide a glimpse of LUCA’s genome," they reasoned.

Most of the genes previously had their functions sussed out, and these painted the aforementioned picture of LUCA.

"This new study provides us with a very intriguing insight into life 4 billion years ago," James O. McInerney an esteemed biologist at the University of Manchester, wrote in an accompanying news article. "When we look at the inferred metabolism of LUCA, we are looking at the dominant and most successful kind of metabolism on the planet before the Bacteria and Archaea diverged."

The study also supports the idea that life likely began near hydrothermal vents, where primitive cells may have been boiled into existence out of the building blocks of life. 

Source: Weiss et. al. "The physiology and habitat of the last universal common ancestor." Nature Microbiology. 25 July 2016. DOI: 10.1038/NMICROBIOL.2016.139

(Images: Jon Sullivan, NASA Astrobiology Institute)

Supervolcanoes May Erupt Surprisingly Fast

Ross Pomeroy - July 21, 2016

Once primed, a supervolcano can decompress and erupt in under a year, a new study shows, offering little warning before a potentially cataclysmic event. 

Supervolcanoes, the hulking geological behemoths that they are, slumber for hundreds of thousands or even millions of years in between eruptions. That's a very good thing, for when they blow, they explode with colossal power, spewing hundreds or even thousands of cubic kilometers of ash across thousands of miles, as well as altering the global climate. 

A quarter of all known supervolcanoes are in the United States, with the best-known dwelling below the picturesque, breathing landscape of Yellowstone National Park. If it were to erupt, it would spew ash as far away as New York. But the sooty dusting that the eastern seaboard would receive would pale in comparison to the ashfall in the heart of the country. Nearby states would be buried under as much as six feet of ash!

Such a scenario seems unlikely to occur anytime soon. None of the world's supervolcanoes currently house magma bodies large enough to produce a cataclysmic eruption. The dormancy has afforded modern humans a chance to thrive globally, and given geologists a chance to safely study supervolcanoes.

Geologists Guilherme Gualda of Vanderbilt University and Stephen Sutton of the University of Chicago recently examined quartz crystal formations left by the supervolcano eruption that created the Long Valley Caldera in California more than 760,000 years ago. Patterns and element concentrations in the crystals are used gauge the evolution of a historical body of magma. In this case, the authors focused on the concentration of titanium to measure the growth rate of crystal rims that mark the final stages of an eruption.

From their analysis, Gualda and Sutton determined that a body of magma below a supervolcano can decompress and erupt in under a year. Their finding disagrees with prior analyses conducted on crystals from the same source, suggesting that this process usually takes over a century.

With their results, the researchers created a rough timeline of a supervolcano explosion. Over tens of thousands of years, the volcanic chamber fills with magma mush of melted rock and solid crystal. Eventually, sufficient magma flows into the chamber and the crystals are expelled. Over the next 5,000 years, the bulging chamber builds pressure. Finally, decompression begins, followed swiftly by an eruption.

“Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption,” Gualda said in a press release.

The timeline is potentially terrifying. If true, it means humanity could be afforded comparatively small notice of a coming eruption.

Source: Gualda GAR, Sutton SR (2016) The Year Leading to a Supereruption. PLoS ONE 11(7): e0159200. doi:10.1371/journal.pone.0159200

(Image: Robert B. Smith via AP)

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