Archive for the ‘Proceedings of the National Academy of Sciences’ Category


Chinese children are lined up in Tiananmen Square in 2003 for photos with the overseas families adopting them. The children in the new study were adopted from China at an average age of 12.8 months and raised in French-speaking families.

You may not recall any memories from the first year of life, but if you were exposed to a different language at the time, your brain will still respond to it at some level, a new study suggests.

Brain scans show that children adopted from China as babies into families that don’t speak Chinese still unconsciously recognize Chinese sounds as language more than a decade later.

“It was amazing to see evidence that such an early experience continued to have a lasting effect,” said Lara Pierce, lead author of the study just published in the journal Proceedings of the National Academy of Sciences, in an email to CBC News.

The adopted children, who were raised in French-speaking Quebec families, had no conscious memory of hearing Chinese.

“If you actually test these people in Chinese, they don’t actually know it,” said Denise Klein, a researcher at McGill University’s Montreal Neurological Institute who co-authored the paper.

But their brains responded to Chinese language sounds the same way as those of bilingual children raised in Chinese-speaking families.


Children exposed to Chinese as babies display similar brain activation patterns as children with continued exposure to Chinese when hearing Chinese words, fMRI scans show.

“In essence, their pattern still looks like people who’ve been exposed to Chinese all their lives.”

Pierce, a PhD candidate in psychology at McGill University, working with Klein and other collaborators, scanned the brains of 48 girls aged nine to 17. Each participant lay inside a functional magnetic resonance imaging machine while she listened to pairs of three-syllable phrases. The phrases contained either:

■Sounds and tones from Mandarin, the official Chinese dialect.
■Hummed versions of the same tones but no actual words.

Participants were asked to tell if the last syllables of each pair were the same or different. The imaging machine measured what parts of the brain were active as the participants were thinking.

“Everybody can do the task — it’s not a difficult task to do,” Klein said. But the sounds are processed differently by people who recognize Chinese words — in that case, they activate the part of the brain that processes language.

Klein said the 21 children adopted from China who participated in the study might have been expected to show patterns similar to those of the 11 monolingual French-speaking children. After all, the adoptees left China at an average age of 12.8 months, an age when most children can only say a few words. On average, those children had not heard Chinese in more than 12 years.

The fact that their brains still recognized Chinese provides some insight into the importance of language learning during the first year of life, Klein suggested.

Effect on ‘relearning’ language not known

But Klein noted that the study is a preliminary one and the researchers don’t yet know what the results mean.

For example, would adopted children exposed to Chinese in infancy have an easier time relearning Chinese later, compared with monolingual French-speaking children who were learning it for the first time?

Pierce said studies trying to figure that out have had mixed results, but she hopes the findings in this study could generate better ways to tackle that question.

She is also interested in whether the traces of the lost language affect how the brain responds to other languages or other kinds of learning. Being able to speak multiple languages has already been shown to have different effects on the way the brain processes languages and other kinds of information.

http://www.cbc.ca/news/technology/adoptees-lost-language-from-infancy-triggers-brain-response-1.2838001

Glaciers in Antarctica are being melted not only by warmer ocean waters but also by underwater volcanoes, a change in our basic understanding of what’s happening underneath West Antarctica’s ice sheet, scientists say.

Geothermal heat from underneath is helping melt the region’s Thwaites Glacier, in the headlines recently for its rapid melt and retreat, researchers at the University of Texas at Austin say.

Scientists in the university’s Institute for Geophysics say they used ice-penetrating radar aboard aircraft to find significant geothermal heat sources — hotter and spread over a broader area than previously thought — underneath the glacier.

Caused by magma moving underground and volcanic activity associated with that movement, geothermal heat might represent a significant factor in changing the stability of the ice mass above, they researchers reported in the Proceedings of the National Academy of Sciences.

Rather than a uniform region of heat beneath, like a pancake griddle, geothermal sources under the Thwaites Glacier more resemble a stove top with a multitude of burners emitting heat in different locations and at different levels, research scientist Don Blankenship says.

“It’s the most complex thermal environment you might imagine,” he says. “And then you plop the most critical dynamically unstable ice sheet on planet Earth in the middle of this thing, and then you try to model it. It’s virtually impossible.”

The geothermal heat under the glacier averages around 100 milliwatts in each square meter, the researchers said, with some hotspots putting out 200 milliwatts per square meter.

Under the Earth’s other continents the average is less than 65 milliwatts per square meter, they said.

The Thwaites Glacer is an outflow glacier — pushing into the Amundsen Sea — that is the size of Florida and hold the key to trying to predict possible future rises in sea levels, they said.

Studying it could help yield clues to the future state of the entire West Antarctic Ice sheet, they added.

A complete collapse of Thwaites Glacier could push global sea levels up by three to six feet, and a melting of the entire ice sheet could double that, the researchers said.

The combination of warm ocean water and underlying geothermal heat makes the future of the glacier difficult to predict, lead study author Dusty Schroeder says.

“The combination of variable subglacial geothermal heat flow and the interacting subglacial water system could threaten the stability of Thwaites Glacier in ways that we never before imagined,” he says.

http://www.techtimes.com/articles/8268/20140610/underground-volcanoes-spur-antartic-glaciar-melt.htm

A study published Monday suggests Americans are less afraid of hurricanes with female names.

This is a real study in the Proceedings of the National Academy of Sciences — not The Onion.

Researchers at the University of Illinois and Arizona State looked at deaths caused by hurricanes between 1950 — when storms were first named — and 2012.

Even after tossing out Katrina and Audrey, particularly deadly storms that would have skewed their model, they found that hurricanes with female names caused an average of 45 deaths, compared with 23 deaths from storms with male names.

In order to back up their findings, the scientists surveyed hundreds of individuals and found that, even on paper, they were less fearful of storms they thought would hit like a girl.

“People imagining a ‘female’ hurricane were not as willing to seek shelter,” said study co-author Sharon Shavitt in a statement. “The stereotypes that underlie these judgments are subtle and not necessarily hostile toward women — they may involve viewing women as warmer and less aggressive than men.”

Hurricanes were traditionally given women’s names, but the National Hurricane Center began the practice of alternating male and female monikers in 1979.

The study suggests that changing a hurricane’s name from Charley to Eloise “could nearly triple its death toll.”

Not everyone is buying it. No two storms are alike, and there could be plenty of other factors that determine how people respond to them.

Hugh Gladwin, an anthropologist at Florida International University, told USA Today the results are “very problematic and misleading.”

But Laura Wattenberg, the creator of the popular naming site BabyNameWizard.com, notes that names do have subtle psychological effects on behavior.

“With a hurricane, you can have 40 million people affected by the same name at the same time,” Wattenberg says. “Even a tiny difference that’s spurred by the reaction to a name could end up having an effect.”

Although a great deal of care is devoted to choosing names for practically everything that has one — babies, consumer products, movies — nothing is as randomly named as a hurricane. Names are selected months and years in advance and then assigned in alphabetical order. There’s no telling which named storm will prove to be a real menace.

Wattenberg suggests choosing names that really pack a punch, “names of villains or markers of fear and evil to get people to act.

“Perhaps our public policy is that we should be naming all the hurricanes Voldemort,” she says.

http://www.npr.org/blogs/thetwo-way/2014/06/02/318277196/study-americans-less-fearful-of-storms-named-after-women?sc=17&f=1001&utm_source=iosnewsapp&utm_medium=Email&utm_campaign=app

By Elizabeth Norton

Cultures around the world have long assumed that women are hardwired to be mothers. But a new study suggests that caring for children awakens a parenting network in the brain—even turning on some of the same circuits in men as it does in women. The research implies that the neural underpinnings of the so-called maternal instinct aren’t unique to women, or activated solely by hormones, but can be developed by anyone who chooses to be a parent.

“This is the first study to look at the way dads’ brains change with child care experience,” says Kevin Pelphrey, a neuroscientist at Yale University who was not involved with the study. “What we thought of as a purely maternal circuit can also be turned on just by being a parent—which is neat, given the way our culture is changing with respect to shared responsibility and marriage equality.”

The findings come from an investigation of two types of households in Israel: traditional families consisting of a biological mother and father, in which the mother assumed most of the caregiving duties, though the fathers were very involved; and homosexual male couples, one of whom was the biological father, who’d had the child with the help of surrogate mothers. The two-father couples had taken the babies home shortly after birth and shared caregiving responsibilities equally. All participants in the study were first-time parents.

Researchers led by Ruth Feldman, a psychologist and neuroscientist at Bar-Ilan University in Ramat Gan, Israel, visited with the families in their homes, videotaping each parent with the child and then the parents and children alone. The team, which included collaborators at the Tel Aviv Sourasky Medical Center in Israel, also took saliva samples from all parents before and after the videotaped sessions to measure oxytocin—a hormone that’s released at times of intimacy and affection and is widely considered the “trust hormone.” Within a week of the home visit, the participants underwent functional magnetic resonance imaging scanning to determine how their brains reacted to the videotapes of themselves with their infants.

The mothers, their husbands, and the homosexual father-father couples all showed the activation of what the researchers term a “parenting network” that incorporated two linked but separate pathways in the brain. One circuit encompasses evolutionarily ancient structures such as the amygdala, insula, and nucleus accumbens, which handle strong emotions, attention, vigilance, and reward. The other pathway turns up in response to learning and experience and includes parts of the prefrontal cortex and an area called the superior temporal sulcus.

In the mothers, activation was stronger in the amygdala-centered network, whereas the heterosexual fathers showed more activity in the network that’s more experience-dependent. At first glance, Feldman says, the finding would seem to suggest that mothers are more wired up to nurture, protect, and possibly worry about their children. The fathers, in contrast, might have to develop these traits through tending, communicating, and learning from their babies what various sounds mean and what the child needs.

“It’s as if the father’s amygdala can shut off when there’s a woman around,” Feldman observes. It could be assumed, she says, that this circuitry is activated only by the rush of hormones during conception, pregnancy, and childbirth.

But the brains of the homosexual couples, in which each partner was a primary caregiver, told a different story. All of these men showed activity that mirrored that of the mothers, with much higher activation in the amygdala-based network, the team reports online today in the Proceedings of the National Academy of Sciences.

This finding argues strongly that the experience of hands-on parenting, with no female mother anywhere in the picture, can configure a caregiver’s brain in the same way that pregnancy and childbirth do, Feldman says.

She adds that in the heterosexual fathers, the activation of the amygdala-based network was proportional to the amount of time they spent with the baby, though the activity wasn’t as high as in the mothers or in the two-father couples.

Feldman does not believe that the brain activity of the primary-caregiving fathers differed because they were gay. Previous imaging studies, she notes, show no difference in brain activation when homosexual and heterosexual participants viewed pictures of their loved ones.

Future studies, Pelphrey says, might focus more closely on this question. “But it’s clear that we’re all born with the circuitry to help us be sensitive caregivers, and the network can be turned up through parenting.”

http://news.sciencemag.org/brain-behavior/2014/05/parenting-rewires-male-brain

When an elephant killed a Maasai woman collecting firewood near Kenya’s Amboseli National Park in 2007, a group of young Maasai men retaliated by spearing one of the animals.

“It wasn’t the one that had killed the woman, says Graeme Shannon, a behavioral ecologist at Colorado State University, in Fort Collins. “It was just the first elephant they encountered—a young bull on the edge of a swamp.”

The Maasai spiked him with spears and, their anger spent, returned home. Later, the animal died from his wounds.

Elephants experience those kinds of killings sporadically. Yet the attacks happen often enough that the tuskers have learned that the Maasai—and Maasai men in particular—are dangerous.

The elephants in the Amboseli region are so aware of this that they can even distinguish between Ma, the language of the Maasai, and other languages, says a team of researchers, who report their findings today in the Proceedings of the National Academy of Sciences.

The results add to “our growing knowledge of the discriminatory abilities of the elephant mind, and how elephants make decisions and see their world,” says Joyce Poole, an elephant expert with ElephantVoices in Masai Mara, Kenya.

Indeed, previous studies have shown that the Amboseli elephants can tell the cattle-herding, red-robed Maasai apart from their agricultural and more blandly dressed neighbors, the Kamba people, simply by scent and the color of their dress.

The elephants know too that walking through villages on weekends is dangerous, as is crop raiding during the full moon.

They’re equally aware of their other key predator, lions, and from their roars, know how many lions are in a pride and if a male lion (the bigger threat because he can bring down an elephant calf) is present.

And they know exactly how to respond to lions roaring nearby: run them off with a charge.

Intriguingly, when the Amboseli elephants encounter a red cloth, such as those worn by the Maasai, they also react aggressively. But they employ a different tactic when they catch the scent of a Maasai man: They run away. Smelling the scent of a Kamba man, however, troubles them far less.

“They have very clear behavioral responses in all of these situations,” says Karen McComb, a behavioral ecologist at the University of Sussex, in the United Kingdom. “We wondered if they would react differently to different human voices.”

To find out, she and her colleagues played recordings to elephant families of Maasai and Kamba men, as well as Maasai women and boys, speaking a simple phrase in their language: “Look, look over there, a group of elephants is coming.”

Over a two-year period, they carried out 142 such playbacks with 47 elephant families, each time playing a different human voice through a concealed speaker placed 50 meters (164 feet) from the animals. They video-recorded the elephants’ reactions to the various human voices, including a Maasai man’s voice they altered to sound like a woman’s.

As soon as an elephant family heard an adult Maasai man speak, the matriarch didn’t hesitate, the researchers say. “She instantly retreats,” Shannon says. “But it’s a silent retreat. They sometimes make a low rumble, and may smell for him, too, but they’re already leaving, and bunching up into a defensive formation. It’s a very different response to when they hear lions.”

In contrast, the voices of Kamba men didn’t cause nearly as strong a defensive reaction: The elephants didn’t consider the Kamba a serious threat.

“That subtle discrimination is easy for us to do, but then we speak human language,” says Richard Byrne, a cognitive biologist at the University of St. Andrews, in Scotland. “It’s interesting that elephants can also detect the characteristic differences between the languages.”

The Amboseli elephants were also sufficiently tuned in to the Maasai language that they could tell women’s and boys’ voices from men’s, seldom turning tail in response. “Maasai women and boys don’t kill elephants,” Shannon points out. Nor were the elephants tricked by the man’s altered voice; when they heard it, they left at once.

“The elephants’ decision-making is very precise,” McComb says, “and it illustrates how they’ve adapted where they can to coexist with us. They’d rather run away than tangle with a human predator.”

Why, one wonders, don’t elephants retreat when poachers descend on them?

“Unfortunately, there are going to be things they cannot adapt to, things such as humans’ ability to come after them with automatic weapons or mass poisonings,” McComb says. “And in those situations, we have to protect them—or we will lose them, ultimately.”

http://news.nationalgeographic.com/news/2014/03/140310-elephants-amboseli-national-park-kenya-maasai-kamba-lions-science/?google_editors_picks=true

Thanks to Da Brayn for bringing this to the It’s Interesting community.

sn-crowdsourcing

Crowdsourcing is the latest research rage—Kickstarter to raise funding, screen savers that number-crunch, and games to find patterns in data—but most efforts have been confined to the virtual lab of the Internet. In a new twist, researchers have now crowdsourced their experiments by connecting players of a video game to an actual biochemistry lab. The game, called EteRNA, allows players to remotely carry out real experiments to verify their predictions of how RNA molecules fold. The first big result: a study published this week in the Proceedings of the National Academy of Sciences, bearing the names of more than 37,000 authors—only 10 of them professional scientists. “It’s pretty amazing stuff,” says Erik Winfree, a biophysicist at the California Institute of Technology in Pasadena.

Some see EteRNA as a sign of the future for science, not only for crowdsourcing citizen scientists but also for giving them remote access to a real lab. “Cloud biochemistry,” as some call it, isn’t just inevitable, Winfree says: It’s already here. DNA sequencing, gene expression testing, and many biochemical assays are already outsourced to remote companies, and any “wet lab” experiment that can be automated will be automated, he says. “Then the scientists can focus on the non-boring part of their work.”

EteRNA grew out of an online video game called Foldit. Created in 2008 by a team led by David Baker and Zoran Popović, a molecular biologist and computer scientist, respectively, at the University of Washington, Seattle, Foldit focuses on predicting the shape into which a string of amino acids will fold. By tweaking virtual strings, Foldit players can surpass the accuracy of the fastest computers in the world at predicting the structure of certain proteins. Two members of the Foldit team, Adrien Treuille and Rhiju Das, conceived of EteRNA back in 2009. “The idea was to make a version of Foldit for RNA,” says Treuille, who is now based at Carnegie Mellon University in Pittsburgh, Pennsylvania. Treuille’s doctoral student Jeehyung Lee developed the needed software, but then Das persuaded them to take it a giant step further: hooking players up directly to a real-world, robot-controlled biochemistry lab. After all, RNA can be synthesized and its folded-up structure determined far more cheaply and rapidly than protein can.

Lee went back to the drawing board, redesigning the game so that it had not only a molecular design interface like Foldit, but also a laboratory interface for designing RNA sequences for synthesis, keeping track of hypotheses for RNA folding rules, and analyzing data to revise those hypotheses. By 2010, Lee had a prototype game ready for testing. Das had the RNA wet lab ready to go at Stanford University in Palo Alto, California, where he is now a professor. All they lacked were players.

A message to the Foldit community attracted a few hundred players. Then in early 2011, The New York Times wrote about EteRNA and tens of thousands of players flooded in.

The game comes with a detailed tutorial and a series of puzzles involving known RNA structures. Only after winning 10,000 points do you unlock the ability to join EteRNA’s research team. There the goal is to design RNA sequences that will fold into a target structure. Each week, eight sequences are chosen by vote and sent to Stanford for synthesis and structure determination. The data that come back reveal how well the sequences’ true structures matched their targets. That way, Treuille says, “reality keeps score.” The players use that feedback to tweak a set of hypotheses: design rules for determining how an RNA sequence will fold.

Two years and hundreds of RNA structures later, the players of EteRNA have proven themselves to be a potent research team. Of the 37,000 who played, about 1000 graduated to participating in the lab for the study published today. (EteRNA now has 133,000 players, 4000 of them doing research.) They generated 40 new rules for RNA folding. For example, at the junctions between different parts of the RNA structure—such as between a loop and an arm—the players discovered that it is far more stable if enriched with guanines and cytosines, the strongest bonding of the RNA base pairs. To see how well those rules describe reality, the humans then competed toe to toe against computers in a new series of RNA structure challenges. The researchers distilled the humans’ 40 rules into an algorithm called EteRNA Bot.

The human players still came out on top, solving structures more accurately than the standard software 99% of the time. The algorithmic version of their rules also outperformed the standard software, but only 95% of the time, showing that the crowdsourced human RNA-folding know-how has not been completely captured yet. The next step, Lee says, is to make the wet lab completely robotic. It still requires humans to operate some of the steps between the input of player RNA sequences and the data output.

EteRNA won’t work for every kind of science, says Shawn Douglas, a biomolecular engineer at the University of California, San Francisco, because a problem has to be “amenable to game-ification.” But he’s optimistic that there will be many more to come. “Many areas of biological research have reached a level of complexity that the mental bandwidth of the individual researcher has become a bottleneck,” Douglas says. EteRNA proves that “there are tens of thousands of people around the world with surplus mental bandwidth and the desire to participate in scientific problem solving.” The trick is to design a good game.

http://news.sciencemag.org/biology/2014/01/online-video-game-plugs-players-real-biochemistry-lab

Thanks to Dr. Rajadhyaksha for bringing this to the It’s Interesting community.

manflu_2774361b

New study suggests that men may actually suffer more when they have influenza because high levels of testosterone can weaken immune response.

For years women have cried “man flu” when men make a fuss over a few sniffles.

But a new study suggests that men may actually suffer more when they are struck down with flu – because high levels of testosterone can weaken their immune response.

The study by Stanford University School of Medicine, examined the reactions of men and women to vaccination against flu.

It found women generally had a stronger antibody response to the jab than men, giving them better protection against the virus.

Men with lower testosterone levels also had a better immune response, more or less equivalent to that of women.

It has long been suggested that men might be more susceptible to bacterial, viral, fungal and parasitic infection than women are.

The study published in the Proceedings of the National Academy of Sciences, found women had higher blood levels of signaling proteins that immune cells pass back and forth, when the body is under threat.

Previous research has found that testosterone has anti-inflammatory properties, suggesting a possible interaction between the male sex hormone and immune response.

Professor of microbiology and immunology Mark Davis said: “This is the first study to show an explicit correlation between testosterone levels, gene expression and immune responsiveness in humans.

“It could be food for thought to all the testosterone-supplement takers out there.”

Scientists said they were left perplexed as why evolution would designed a hormone that enhances classic male sexual characteristics – such as muscle strength, beard growth and risk-taking propensity – yet left them with a weaker immune system.

Previous studies have found that while women may accuse men of exaggerating when they have flu, females who are more likely to admit to having sniffles and sneezes.

The research, carried out by London School of Hygiene and Tropical Medicine last winter, shows that women are are 16 per cent more likely to say they are ill.

http://www.telegraph.co.uk/health/healthnews/10536083/Man-flu-the-truth-that-women-dont-want-to-hear.html

Artist's impression of planets discovered by Kepler spacecraft

Our galaxy probably contains at least two billion planets that, like Earth, have liquid water on their surfaces and orbit around their parent stars in the “habitable zone” for life. The nearest, according to astronomers, could be a mere 12 light years away.

A new study, published on Monday in the Proceedings of the National Academy of Sciences, suggests that Earth-like planets capable of supporting life are far more common than previously thought. Using measurements from Nasa’s Kepler space observatory, scientists led by Erik Petigura at the University of California, Berkeley, estimated that 22% of our galaxy’s sun-like stars have rocky planets circling them in the zone where they get roughly the same amount of light energy as Earth receives from the sun. There are around 100bn stars in our galaxy, of which 10% are like the sun.

So far Kepler has studied more than 150,000 stars and identified more than 3,000 candidate planets, but many of these are “gas giants”, similar to Jupiter, that orbit close to their parent stars. If there is life out there, it is far more likely to have evolved on rocky planets with liquid water on their surfaces, similar to Earth.

To get their results, Petigura’s team looked for planets in Kepler data that had a radius up to double that of Earth. They searched for planets that orbited far enough from their star that liquid water would not evaporate, but not so far that the water would all freeze.

Subhanjoy Mohanty, an astrophysicist at Imperial College London who was not involved with the study, said: “This is the first estimate of the frequency of Earth-like planets around sun-like stars, in orbits large enough to lie in the habitable zone of their stars. The finding that roughly one in five sun-like stars may host such planets is an incredibly important one, probably exceeding the expectations of most cautious astronomers.”

He added that the latest analysis increased the chances that there might be life somewhere among the stars. “Previous analyses of Kepler data had shown that red dwarfs – the most common type of star in the galaxy, making up about 80% of the stellar population – very frequently harbour Earth-size planets, including in their habitable zones. This new study shows that the same is true around stars more like our own sun. This is certainly an added impetus for planned future missions which will study the atmospheres of these potentially habitable planets, enabling us to investigate whether they are in fact habitable or not, and also whether their atmospheres show actual biosignatures of existing life.”

Nasa also announced on Monday that the Kepler probe would be given a new lease of life, following fears that it would have to end its mission after only four years in space. In May 2013, scientists discovered that one of the gyroscopic wheels – known as “reaction wheels” – that kept the probe pointing in the right direction had stopped working and, try as they might, Nasa engineers could not restart it. Unable to point itself at the stars with any accuracy, the probe could no longer be used to collect data about the position of new exoplanets.

But it looks as though there could be a solution that involves reorienting the probe to look along the plane of the galaxy, which will allow it to remain stable with only two of its reaction wheels working. “The old saying ‘necessity is the mother of invention’ has rung true here, with engineers and scientists from Nasa and the spacecraft manufacturers having figured out this way to – we hope – recover much of the performance we thought we had lost. We are very excited,” said Bill Chaplin, an astrophysicist at the University of Birmingham in the UK.

If all goes well, the new Kepler mission – dubbed “K2” – will look for planets around smaller stars than the sun, and will also study the stars themselves. “There are a wealth of fantastically interesting targets for astrophysics that can be observed in the ecliptic plane, which were not accessible in the original Kepler field, notably brighter clusters of stars – where the common origins and distances to these stars make the clusters excellent laboratories for testing our understanding of stars – and young, star-forming regions,” said Chaplin.

http://www.theguardian.com/science/2013/nov/04/planets-galaxy-life-kepler

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

earqwax

Using built-up earwax taken from a blue whale carcass, researchers have been able to reconstruct a picture of its life by the chemicals and hormones in its ears.

The whale in question was a male blue whale that died after it was struck by a ship near Santa Barbara, Calif., in 2007. Researchers removed a 10-inch ear plug from the carcass during a necropsy. They did a careful chemical analysis of it to measure what the whale had been exposed to in its lifetime. The study appeared in a recent edition of the journal Proceedings of the National Academies of Science.

The scientific community has been excited about the possibilities raised by the new method “once they get past the ‘eew!’ factor of it being earwax,” says Stephen Trumble, lead author on the paper and a biology professor at Baylor University in Waco, Texas.

Baleen whales are known to accumulate layers of earwax in their ear canal. These create a waxy plug that can be over a foot long. The earwax is laid down in layers, a dark one when the animal is feeding and a light one when the animal is migrating and eats very little. The layers are routinely used to determine whale ages.

Now by analyzing the chemicals, pollutants and other matter that accumulated in that wax, researchers were able to build a very complete picture of the animal’s life and exposure to chemicals.

The whale was likely born around 1995. It was exposed to large concentrations of persistent organic pollutants such as DDT and other pesticides in the first six months of its life, most likely while it was still nursing. Many mammals are known to pass chemicals through milk and researchers believe that’s what happened to this whale.

DDT is one of a group of persistent organic pollutants that can take decades to break down in the environment. Although it was banned in the United States in 1972 it is still found in the world’s oceans, and was present at higher levels when this whale was born.
There were also two spikes in its exposure to mercury, around ages 5 and 10. The researchers think these might have occurred as the animal migrated past the coast of California, possibly exposing it to higher levels of pollution than it encountered in the open ocean and when passing less polluted land masses.

When it was about 10 years of age researchers believe it became sexually mature because of increases in testosterone. Its stress hormones spike right around that time, too, which the researchers believe might have been linked to breeding competition or social bonds it formed during this period.

The method offers researchers a much easier and more precise way of measuring what whales are exposed to than previous methods, which included examining whale blubber, blood, feces and blowhole spray, says Sascha Usenko, a professor of environmental chemistry and one of the Baylor researchers.

Since their paper was published they’ve been getting offers of whale earwax specimens, called plugs,from around the world. “We’re going to receive one hopefully this week that’s about three and a half feet long from a bowhead whale from Barrow, Alaska,” Trumble said.

http://www.usatoday.com/story/news/nation/2013/10/10/whale-earwax-gives-researchers-peek-whale-life/2861591/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+usatoday-NewsTopStories+(USATODAY+-+News+Top+Stories)

testivcle

A link between the size of a father’s testicles and how active he is in bringing up his children has been suggested by scientists.

Researchers at Emory University, US, said those with smaller testicles were more likely to be involved with nappy changing, feeding and bath time.

They also found differences in brain scans of fathers looking at images of their child, linked to testicle size.

But other factors, such as cultural expectations, also played a role.

Levels of promiscuity and testicle size are strongly linked in animals, those with the largest pair tending to mate with more partners.

The researchers were investigating an evolutionary theory about trade-offs between investing time and effort in mating or putting that energy into raising children. The idea being that larger testicles would suggest greater commitment to creating more children over raising them.

The study, in Proceedings of the National Academy of Science, looked at the relationship between testicle size and fatherhood in 70 men who had children between the ages of one and two.

The team at Emory University in Atlanta performed brain scans while the men were shown pictures of their children.

It showed those with smaller testicles tended to have a greater response in the reward area of the brain than those with a larger size.

MRI scans showed a three-fold difference between the volumes of the smallest and largest testicles in the group.

Those at the smaller end of the spectrum were also more likely, according to interviews with the man and the mother, to be more active in parenting duties.

One of the researchers, Dr James Rilling, told the BBC: “It tells us some men are more naturally inclined to care-giving than others, but I don’t think that excuses other men. It just might require more effort for some than others.”

The exact nature of any link is not clear.

The researchers believe the size of the testicles, probably through the hormone testosterone, is affecting behaviour. But it is not clear if the process of having a baby may have some effect on the father.

“We know, for instance, that testosterone levels go down when men become involved fathers,” said Dr Rilling.

Further studies, involving analysing the size before and after becoming a father, are still needed.

Cultural and societal expectations on the role of the father are also not accounted for in the study.

All of the men were from the Atlanta area so the relative impact of society and biology has not been measured.

http://www.bbc.co.uk/news/health-24016988

Thanks to Dr. D and Kebmodee for bringing this to the attention of the It’s Interesting community.