RealClearScience Journal Club

Science Figures Interpreted and Analyzed by RealClearScience

Three Hypotheses to Explain Mars' Methane

Ross Pomeroy - June 27, 2016

In December 2014, NASA scientists confirmed the presence of methane on Mars. The Curiosity rover detected a massive spike in methane levels over a 60-day period. Levels of the organic compound surged in the atmosphere from roughly 0.7 parts per billion all the way up to 7 parts per billion, and subsequently returned to background levels.

The discovery settled a decade-long debate. Not only does the Red Planet contain appreciable amounts of methane in its atmosphere, levels of the organic compound fluctuate, indicating a potential source on Mars itself. Knowing that Earth's methane is primarily produced by living organisms, Mars enthusiasts were abuzz with excitement. Could life be manufacturing Mars' methane as well?

Indeed, that is one of the explanations entertained by a team of scientists based out of NASA's Jet Propulsion Laboratory and the California Institute of Technology. In a new paper published to the journal Astrobiology, Dr. Renyu Hu and his colleagues confirm that perchlorate salts on Mars underneath Gale Crater can convert to a liquid state. With this in mind, Hu and his team offered up three testable hypotheses for the origin of Mars' methane.

First, the regolith of rocks, dirt, and soil overlying the perchlorate salts at Gale Crater collects methane when dry and releases it when the salts liquefy. This would be a seasonal process, occurring in early Martian winter when the humidity rises to a sufficient level.

Second, there may be a deep subsurface aquifer containing methane, which periodically releases bursts of the compound into the atmosphere. The aquifer could be buried as far as five kilometers deep. Moreover, they may be sealed by ice, similar to tundras on Earth.

Third, yeast-like microorganisms called methanogens convert organic matter in the soil to methane when the perchlorate salts turn to liquid. Like the first hypothesis, this would again ocurr on a seasonal basis. While undoubtedly the most exciting explanation, this is also the most unlikely. The researchers, however, turn to examples on Earth for hope.

"Methanogens thrive in some of the harshest environments on Earth, including extremely acidic environments and inside Greenland glacial ice three kilometers deep, which is analogous to Martian subsurface ice environments."

Unfortunately, this explanation took a significant hit in May as Curiosity watched its second Martian winter pass without a spike in methane levels similar to the first one. This suggests that the methane release was not seasonal in nature.

Each of the competing explanations are constantly tested as the Curiosity rover continues its stay on the Red Plant, the researchers say. One of them may eventually be proven correct.

"Any of the three hypotheses, if confirmed, leads to profound ramifications in our understanding of Mars as an active and potentially habitable world."

Source: Renyu Hu et. al. Hypotheses for Near-Surface Exchange of Methane on Mars. Astrobiology. June 2016 DOI: 10.1089/ast.2015.1410

(Image: NASA)

Bees Commit Suicide to Save Colony From Parasites

Ross Pomeroy - June 8, 2016

When a virus infects a cell inside a living organism, it quickly moves to hijack its new host. Once commandeered, the cell will become a helpless pawn in the virus' nefarious mission to replicate and spread throughout the body. That's why the cell quickly takes a drastic move: it commits suicide. Rather than linger on as a puppet for the invading virus, the cell disintegrates in a process called apoptosis, sacrificing itself for the sake of the whole organism.

According to new research published in Scientific Reports, the Eastern honey bee, Apis cerana, does almost exactly the same thing!

A bee colony is much more than a mere collection of individual organisms; it is an organism itself. In fact, scientists have taken to calling colonies of socially-organized insects (like bees or ants) "superorganisms." In this manner of looking at things, individual bees are comparable to the cells inside your body. And just like the cells in your body can be infected with viruses, the bees in a colony can also be infected... with microscopic parasites.

For years, the Eastern honeybee has been besieged by one such parasite, ominously named Varroa destructor. Within an infested colony, the mites feed on the blood of individual bees and spread disease. But the Eastern honey bee has been fighting back. While colonies once died in couple years, they are now resisting and even surviving. This has prompted the parasite to switch its primary host to the Western honey bee, A. mellifera, the most common honey bee species worldwide. The mites are now significantly contributing to the Colony Collapse Disorder plaguing the species.

According to the new study, the Eastern honey bee's resistance to V. destructor seems to be fueled by what the researchers have dubbed "social apoptosis." Rather than struggle to survive when infested with mites, worker larvae of the Eastern honey bee die much more easily, preventing the mites' spread. The researchers turned up the finding after infesting the larvae of five colonies of Eastern honey bees and six colonies of Western honey bees with V. destructor. While Western honey bee larvae developed normally, Eastern honey bee larvae developed much more slowly, and often didn't develop at all (see example above). (Below figure: Eastern honey bees (A. cerana) take much longer to develop than Western honey bees (A. melifera).)

"The observed social apoptosis is most likely a fundamental defence mechanism of social insect colonies to combat diseases," the researchers write.

"Our counterintuitive result shows that susceptible individuals can benefit the superorganism, which goes against the common assumption that ‘strong’ elements of a social entity are required to ensure group survival."

The authors suggest that breeding Western honey bees that demonstrate the behavior could help to combat Colony Collapse Disorder. Between 2007 and 2013, almost 10 million bee hives have been lost to the disorder.

Source: Page, P. et al. Social apoptosis in honey bee superorganisms. Sci. Rep. 6, 27210; doi: 10.1038/srep27210 (2016)

Call of Duty: A Great Way to Train Your Brain

Ross Pomeroy - June 4, 2016

When watching their children play video games, parents across America once rolled their eyes and shook their heads. (Many still do.) "Those games will rot your brain," they'd say, before strolling out of the room in a huff of superiority. But over the past two decades, study after study has shown just the opposite. Rather than rot the brain, action video games instead seem to boost it.

A new meta-analysis just published to Frontiers in Psychology drills the point home. "Action video game training may serve as an efficient way to improve the cognitive performance of healthy adults," the researchers say. Parents included!

The authors, primarily based out of the Chinese Academy of Sciences, dug up twenty years worth of research for their analysis, including only trials that involved action video games, conducted on healthy adults, with a sufficient control group. Their search turned up twenty studies. In each study, subjects played video games then completed varying tasks designed to test cognitive function. The studies lasted weeks or even months. Over those varying durations, subjects played games like Call of Duty, Medal of Honor, and Unreal Tournament for an average of 22 hours.

Pooling the results of each experiment into a large analysis involving over 600 individuals, the reviewers found that action games produced a moderate beneficial effect on overall cognition. Functions like processing speed and attention, visuospatial processing, executive function, and even memory all improved over controls.

Attempting to explain the results, the authors noted that action video games demand quick and accurate reactions, focus, and the ability to concentrate on multiple targets. They also cited recent research showing that playing video games can produce structural changes in the brain.

Generally, younger adults experienced greater cognitive benefits from action video games, which the authors attributed to greater neural plasticity.

Of course, most of the 155 million Americans who play video games don't do so for the cognitive benefits; they play for the fun of it. The potential boost to brain function is an added bonus!

Source: Wang P, Liu H, Zhu X, Meng T, Li H and Zuo X (2016). Action Video Game Training for Healthy Adults: A Meta-Analytic Study. Front. Psychol. 7:907. doi: 10.3389/fpsyg.2016.00907

(Image: AP)

Study: LEGOs Are Becoming More Violent

Ross Pomeroy - May 23, 2016

There's little doubt that popular media has grown increasingly violent of late. In television shows, movies, and video games, violence is more prevalent and more graphic. Game of Thrones, and the now yearly arrival of the latest Marvel movie, are hallmarks of this trend.

Even children's toys can't escape the trend. A new study published to PLoS ONE finds that violence is growing increasingly common in LEGO sets.

Since 1949, LEGO has granted children of all ages an outlet to express their creativity. The near 600 billion parts produced over that time have been used to craft all sorts of wondrous creations.

LEGO builders are still free to erect whatever they choose, but the tendered designs and themes, as well as the parts themselves, are becoming more violent in nature.

To discern the finding, a group of researchers from New Zealand conducted two experiments. First, they analyzed a massive database of LEGO parts and sets to uncover the proportion of parts that are weapons and the proportion of sets that contain weapons. Though the data contains a number of outliers, there seems to be a broad trend of rising weaponization. The change is particularly apparent since the turn of the century. In 2001, just 3 percent of LEGO sets sold contained weapons. In 2014, that proportion was nearly 30 percent!

In a second experiment, the research team recruited 161 volunteers to analyze the level of violence presented in LEGO catalogs since 1973. When the researchers poured through the volunteers' ratings, they found a clear trend of increasing violence.

The trend is unsurprising. LEGO does not exist a vacuum. The sets the company produces mimic the popular entertainment brands of today. And as kids are increasingly bombarded and even enthralled with violence in movies and on TV, the LEGO Company will give them the tools to build what they watch.

As a result, "The LEGO Company’s products are not as innocent as they used to be," the researchers conclude.

Source: Bartneck C, Min Ser Q, Moltchanova E, Smithies J, Harrington E (2016) Have LEGO Products Become More Violent? PLoS ONE 11(5): e0155401. doi:10.1371/journal.pone.0155401

(Top Image: LEGO Company)

A Spider in Madagascar Engages in Oral Sex

Ross Pomeroy - May 2, 2016

Darwin’s bark spiders produce the toughest known silk in the entire world. The stuff is ten times more resistant to breakage than Kevlar! But the arachnids' silk-making prowess rates second to their sexual prowess, apparently. A new study published to Scientific Reports shows that males of the species perform oral sex on females up to 100 times during copulation.

Researchers from the Scientific Research Centre of the Slovenian Academy of Sciences and Arts and the Smithsonian's National Museum of Natural History traveled to Andasibe-Mantadia National Park in Madagascar to get up-close and personal with Darwin's bark spiders, the males of which measure in at roughly 6 millimeters long, while the females stretch about 20 millimeters. The team intently observed 29 separate matings in both the laboratory and the wild. In all instances, the smaller males performed cunnilingus on the vastly larger females. As the authors arousingly described:

"Typically, a performing male first hooked one of his cheliceral fangs to female’s copulatory opening, turned his body perpendicular to the female, then orally secreted fluids into the copulatory openings."

Marvin Gaye couldn't have said it any better.

The researchers suggest two likely hypotheses for the behavior. First, oral sex may signal mate quality -- to the better-skilled and more physically able male go the spoils! Second, enzymes in the males' saliva may render the environment inside the females' genital organs more hospitable to their sperm.

Oral sex is well documented in mammals. Notable givers include macaques, lemurs, bonobos, hyenas, cheetahs, lions, dolphins, bats, and (of course) humans. But throughout the rest of the animal kingdom, the act is not as well known. Male fruit flies lick female genitalia, an action that's rewarded with longer mating bouts. Also, there are spotty reports of oral sex occurring amongst widow spiders.

The researchers also observed bark spiders engaging in other risqué sexual acts, including sexual cannibalism, where the female eats the male, and mate-binding, in which the male envelopes the female in silk to avoid said cannibalism. Believe it or not, these acts weren't nearly as surprising as the oral sex.

Source: Gregorič, M. et al. Spider behaviors include oral sexual encounters. Sci. Rep. 6, 25128; doi: 10.1038/srep25128 (2016).

Raising Income Taxes Won't Fix Wealth Inequality

Ross Pomeroy - April 27, 2016

The top 10% of Americans control roughly three-quarters of the nation's wealth, and the minority of Haves are continuing to accumulate more than the majority of Have-Nots.

This is wealth inequality in the United States. And though it doesn't attract as much attention as income inequality, it's arguably far more important, imposing economic instabilities and social strife.

To decrease wealth inequality, pundits, politicians, and economists often suggest raising income tax rates on top earners to as high as 50, 70, or even 90 percent.

The idea sounds plausible, but according to a new study published to PLoS ONE it probably won't work in practice.

To distill the finding, a team of researchers based out of Tel-Aviv University first developed an algorithm to model wealth inequality in the United States between 1930 and 2010. Primarily based on income from wages, income from wealth (profits, rents, dividends, etc.), and changes in capital value (property, shares, etc.) the resulting model correlated closely (p=.96) with historical data on wealth inequality.

The researchers then used their model to predict the future. What would happen, they wondered, if income inequality was varied? In their model, income inequality was tied to a metric called the Gini index, a statistical measure of inequality used for decades. They found that altering income inequality to a Gini index of 0.1 (very low inequality) resulted in the top 10% controlling 78.6% of wealth in 2030, while raising income inequality to a Gini index of 0.9 (very high inequality) resulted in the top 10% controlling 79.3% of wealth in 2030, hardly a significant difference.

According to the researchers, the lack of effect isn't actually surprising.

"When income tax is increased, the top earners, who are not necessarily the wealthiest individuals in the population, have a larger difficulty of accumulating wealth, with respect to the wealthiest. On the other hand, it barely affects the wealthiest individuals. Therefore, such an increase might even deepen the wealth gap."

"Progressive taxation, which might have a significant effect on the distribution of income, will have a small effect on wealth inequality," they add.

The team behind the current study is not the only group to return such a result. Just last year, experts at the Brookings Institute created their own model and found that increasing the top tax rate from 39.6% to 50% wouldn't even dent income inequality, let alone wealth inequality.

As is the status quo with most economic models, the researchers' model suffers from a couple key limitations. Specifically, it did not address economic mobility, nor did it include inheritance taxes.

Taxes on inheritance and capital gains would likely have more of an impact on wealth inequality, as they directly tax wealth, not income.

Source: Berman Y, Ben-Jacob E, Shapira Y (2016) The Dynamics of Wealth Inequality and the Effect of Income Distribution. PLoS ONE 11(4): e0154196. doi:10.1371/journal.pone.0154196

(AP Photo/Janerik Henriksson, File)

Soccer Players Conveniently 'Get Injured' When Their Team Benefits From It

Ross Pomeroy - April 15, 2016

Watching a soccer match can be very much like watching a sitcom with terrible acting. To gain an advantage and help their team win, players regularly engage in acrobatic, unsporting antics, which may include flamboyantly falling to draw a foul, feigning an injury to waste time, or crying out in pain while clutching their neck after beingly lightly tapped on the shoulder.

Savvy futbol fans, of course, aren't buying it. In Seattle, the 40,000+ Sounders faithful chant in unison, "Let him die!" when they deem the "injured" player to be a faker. Now, a new study published to the journal Frontiers in Psychology has confirmed what Seattle fans -- and all other soccer fans -- suspected: footballers are huge floppers.

Researchers based out of the National University Singapore and the University of Birmingham watched thirty Euro 2008 soccer matches, 90 English Premier League matches and 63 World Cup 2010 matches, charting injuries for each team over the duration of every match. The timing of injuries was divided into six periods: 0-15th minute, 16-30th minute, 31-45th minute (including first-half stoppage time), 46-60th minute, 61-75th minute and 76-90th minute (including second-half stoppage time). The injuries themselves were categorized based upon whether they would benefit or not benefit the team of the injured player. For example, if a player suffered an injury when his team was up by a goal, that would constitute a "benefit" injury, as it would slow the game down and give his teammates a break.

The researchers focused only on consequential games. Thus, forty-nine of the 183 matches were discounted because their outcomes were meaningless in the context of the competition or they were blowouts, in which one team led by three or more goals.

When the researchers tallied and categorized the injuries, the results were clear: Towards the end of a game, players on teams that would benefit from an injury were far more likely to suffer an injury. What a coincidence!

Of course, this is almost certainly not a coincidence -- the players are simply faking their injuries.

The researchers interviewed three anonymous managers in the English Premier League about the obvious tactic.

"None of the three managers admitted to actively instructing players to feign injury but all were somewhat ambivalent in their condemnation of such behaviour," the researchers wrote. "One described it as 'clever', another admitted that players did it, 'to take the steam out of the game' and the third admitted they might tell a player to stay down, 'and take a breather.'"

Source: Derbyshire SW, Angel I and Bushell R (2016). When pain brings gain: Soccer players behaviour and admissions suggest feigning injury to maintain a favourable scoreline. Front. Psychol. 7:613. doi: 10.3389/fpsyg.2016.00613

(AP photo)

Study Reveals Habits of Sexually Satisfied Couples

Ross Pomeroy - April 11, 2016

It's not always easy to keep the passion alive in a long-term relationship, but many couples manage to do it. In a recent study published to The Journal of Sex Research, scientists sought to learn the secrets of partners in sexually satisfying relationships. What do they do that those in sexually dissatisfying relationships do not?

Led by Chapman University Professor David Frederick, the team of researchers examined a massive data set of over 38,000 men and women who reported being in a relationship for at least three years. The subjects completed an in-depth, anonymous survey hosted on back in 2006, in which they responded to a host of questions about their backgrounds, their relationships, and their sex lives.

From the data, the researchers discovered a number of habits associated with a sexual satisfaction. Men and women in sexually satisfying relationships were far more likely to try new sexual positions, talk dirty during sex, wear titillating lingerie, bathe together, give each other massages, go on romantic getaways, try anal stimulation, use sex toys, and say "I love you" during sex.

Most importantly, sexually satisfied men and women were far more likely to communicate openly about their sexual desires. The vast majority of men and women who said they were dissatisfied with their sex lives indicated that it was important to them to have an exciting sex life, yet over sixty percent of them agreed with the statement, "I feel that my partner doesn’t know how to excite me." That is a problem that can be solved by maintaining an open and honest dialogue about sex.

The survey benefited from its placement on a popular website -- the study group was immense and diverse. However, the study is limited by self-selection -- subjects weren't chosen at random.

During a recent interview on the Savage Lovecast, lead author David Frederick cautioned that the data is correlational. Merely adopting the habits of sexually satisfied couples isn't guaranteed to transform a sexually dissatisfying relationship, but it just might.

"For the dissatisfied couples, it's something they can take a look at and say 'Why don't we try this and see what happens?'"

Source: David A. Frederick, Janet Lever, Brian Joseph Gillespie & Justin R. Garcia (2016): What Keeps Passion Alive? Sexual Satisfaction Is Associated With Sexual Communication, Mood Setting, Sexual Variety, Oral Sex, Orgasm, and Sex Frequency in a National U.S. Study, The Journal of Sex Research, DOI: 10.1080/00224499.2015.1137854

(Image: Shutterstock)

Link Between Exclamation Points and Knowledge

Alex B. Berezow - April 1, 2016

We have noticed a striking (and disturbing) inverse relationship between the use of exclamation points in Internet comments and knowledge of the subject at hand.*

*Note: This is not based on a real study, but it's nonetheless true. Happy April Fools' Day!

When Societies Make Women's Health a Priority, Everyone Benefits

Ross Pomeroy - March 31, 2016

In an exhaustive systematic review published to the journal PLoS ONE, researchers based out of the Chan School of Public Health at Harvard University find that investing in women's health produces economic, societal, and humanitarian benefits that persist for generations.

Kristine Husøy Onarheim, Johanne Helene Iversen, and David E. Bloom scoured a number of databases for research pertaining to "women, health, and economics" published between 1970 and 2013. The trio screened 20,834 papers before eventually settling on 124 relevant, high-quality articles for their review. Pouring through every single study, the reviewers uncovered a great many positive outcomes that come from prioritizing women's health. Here are some highlights:

  • Meeting one-third of the need for family planning in Kenya, Nigeria, and Senegal could increase per capita income in each country by 8 to 13 percent. Meeting all of the unmet need for contraception could result in income gains of 31 to 65 percent.
  • In a study conducted in Tanzania, "children of mothers living in areas with iodine supplementation programs attained an estimated 0.35–0.56 years of additional schooling, compared with children living in areas without supplement programs."
  • The availability of oral contraception in the U.S. is associated with a greater number of women pursuing higher education and professional careers.
  • "Greater access to abortion in the U.S. is associated with higher rates of college graduation, lower rates of single parenthood, and lower odds of welfare receipt."
  • "Poor maternal health is associated with diminished child health, with implications for birth weight, neonatal survival, cognitive development, child behavior, school performance, and adult health and productivity," the reviewers found, and these negative effects can spiral into a vicious cycle (displayed below). Programs that remedy maternal malnutrition and poverty benefit mothers, children, and indeed all of society for decades to come.

The reviewers arrived at four primary conclusions:

"First, healthier women contribute to better-educated and more productive societies. Second, ensuring women’s control over their own fertility can boost the pace of economic growth and development. Third, maternal health is crucial to the health and economic wellbeing of subsequent generations through intergenerational spillovers. Fourth, further study is needed on women’s health and household and societal productivity."

"These results demonstrate the necessity and efficacy of investment in initiatives that address women’s health," the reviewers write. "Societies that prioritize women’s health will likely have better population health overall, and will remain more productive for generations to come."

Source: Onarheim KH, Iversen JH, Bloom DE (2016) Economic Benefits of Investing in Women’s Health: A Systematic Review. PLoS ONE 11(3): e0150120. doi:10.1371/journal.pone.0150120

More Journal Club

The Girl Who Injected Herself With Mercury
March 29, 2016

Silvery, shiny, and the only metal that's liquid at room temperature, Mercury is a mesmerizing element. But...

Money Makes Men Think Their Partners Are Less Physically Attractive
March 22, 2016

Money does funny things to the mind. Merely thinking about it can alter perceptions of pain and feelings of...

Should We Save 'Endangered' Cultures?
March 14, 2016

Though hard to imagine for residents of the technologically developed world, there remains hundreds of tribes...

Journal Club Archives