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How we feel can change how we taste fat

The child on the right will be both depressed and unable to taste fat once the ice cream falls out of his cone.

We’ve all done it: after a rough day, you come home and open a bag of M&Ms or potato chips and polish off the whole thing before even realizing it. It's often as simple as being tired, distracted, or hungry. However, new research suggests that it’s possible you weren’t even able to taste that fatty goodness, which may be why you just kept on eating. A paper published last week in PLoS ONE suggests that there is a complex relationship between emotional arousal, symptoms of depression, and taste perception, and that this phenomenon could have links to emotional overeating.

Previous studies have suggested that both depression and strong emotions can affect how and what we taste. Now that fat has been shown to stimulate taste receptors in a similar way to other qualities like sweetness and bitterness, a group of German researchers wondered whether our psychological state could also affect how we taste and perceive fat.

To test this relationship, the researchers brought in 80 subjects (48 women and 32 men) from 19 to 47 years old. The participants were asked a few questions about their lifestyle and were each given a questionnaire called Beck's Depression Inventory, which evaluates depression-related symptoms such as irritability and feelings of guilt. Based on the responses, the subjects were divided into two groups: the “subclinical depression” group, each of whom had depression scores lower than the median, and the “no subclinical depression” group, who had depression scores that were higher than the median.

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Female breadwinners are a sign of progress—not an affront to science

U.S. Government Printing Office, 1943.

According to a new Pew poll, women are the primary source of income in forty percent of all households with children. In 1960, mothers were the primary breadwinners in just 11 percent of households.

Most rational people would see these findings as progress, since they suggest that women are no longer bound by the traditional gender stereotypes that have long kept them out of the workforce. They are an indication that gender equality is making strides in the right direction. At the very least, there’s no reason women with families shouldn’t have successful careers—right?

Not according to the (note: all male) commentators from Fox Business. In their analysis of the survey, the hits come early and often. In his opening summary of the research, Lou Dobbs says the Pew study finds “that women have become the breadwinners in this country, and a lot of other concerning and troubling statistics.”

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Giant genome study finds tiny links between genetics and schooling

Everyone wants an easy answer to the big questions about genetics—is there a gay gene? A gene for autism? What about for motherhood or for murder?

In nearly every case, the answer is no; instead, genetic traits are often determined by many small mutations across the genome that interact with the environment and peoples’ experiences. Finding these genetic differences and interpreting their effects is incredibly difficult. The studies that identify them, called genome-wide association studies, entail searching the entire genome of many individuals for areas that consistently correlate with specific traits.

Casting such a wide net necessitates a large sample size, since hundreds of thousands of genetic markers are being tested. Until recently, the most extensive genome-wide association study in the social sciences involved about 10,000 individuals. A new study detailed in this week's Science examines the genomes of about 100,000 people across fifteen countries in order to identify genetic markers related to a person’s educational accomplishments.

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Offering rewards boosts blood donations despite ban on payments

While it’s illegal to pay someone for a kidney or a lobe of their liver, it’s completely legal to offer blood donors a small reward for giving a pint or two of blood. But for some people, accepting a reward in exchange for a blood donation raises both eyebrows and moral questions. To some, it’s the first small step down a slippery slope that ends in black markets and paid organ trade. There’s also the question of where a donor’s motivation should come from. In theory, it’s akin to paying kids for good grades in school; shouldn't the motivation come from an intrinsic drive to be a better person, not a reward from an outsider?

And when it comes to blood donations, there’s an additional worry. Critics claim that economic incentives could encourage potential donors to lie about their health history or personal habits, threatening the safety and integrity of the blood supply. Due to this public health concern, the World Health Organization has spent four decades advising against economic incentives for blood donors.

But based on the cumulative findings of several recent studies, Nicola Lacetera, Mario Macis, and Robert Slonim argue that these guidelines are fundamentally flawed. When implemented correctly, these researchers say, economic rewards can benefit the blood supply without threatening its safety.

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Erectile function: bats mop up nectar with “hairy” tongues

As sweet as the reward is, it isn’t easy being a nectar-feeder. Bats, hummingbirds, and bees face the difficult task of sipping as much nectar as possible from a tiny floral tube, all while hovering delicately in the air. And since hovering is such an energy-demanding task, the more efficiently these animals can slurp up nectar, the likely they are to get something out of a visit to a flower.

Hummingbirds have evolved a creative adaptation to deal with this challenge: the tips of their long tongues are bifurcated, or split. During feeding, nectar is trapped between the two tongue tips and carried into the bird’s mouth. Long-tongued bees have solved the problem in a slightly different way: they have a brush-like structure on the end of their tongue to help lap up nectar. Nectar-feeding bats have similar hairy projections on the end of their tongue, and researchers have long assumed that these were simply static structures that increased the surface area of the tongue to make nectar feeding more efficient.

However, a new study in PNAS suggests that a nectar-feeding bat’s tongue is far more efficient—and more complicated—than scientists previously assumed.

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Stressed out moms mean faster growing babies—if you’re a squirrel

To give her offspring better odds in life, a mom can contribute all sorts of advantages: good genes, healthy milk, protection from predators, and more. Red squirrels—cousins of the more robust gray squirrels—are no exception. But new research in the journal Science shows that for these rodents, one such maternal boost stems from a surprising source: stress.

The research was conducted by a group of scientists who have spent the last 22 years studying a group of wild red squirrels in the Yukon. The ecosystem there follows an episodic pattern: every few years, when the spruce trees produce seeds en masse, the squirrel population booms in response. The team’s previous research had shown that in the years when squirrel numbers are especially high, fast-growing offspring tend to fare better than those that grow more slowly, presumably since they are better equipped to outcompete their rivals.

But how, exactly, do some squirrels end up growing so quickly?

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When it comes to vaccination, bad news is contagious

In recent years, the controversy about vaccine safety has exploded online. Fueled by pseudoscience, conspiracy theories, and ignorance, a surprisingly large number of people today refuse to vaccinate themselves or their children. According to a 2011 poll, nearly a quarter of Americans have changed their opinion on vaccination in the last five years, and for the vast majority of these people, that change has been in a negative direction.

There’s no better tool than social media to spread information—and misinformation—about controversial topics quickly and efficiently, and there has been speculation that these outlets have played a role in heightening concerns about vaccination. But how do opinions about health-related behaviors spread over social media?

A group of researchers from Penn State used Twitter to answer this question, and their findings were published in EPJ Data Science last week.

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By building “fairy circles,” termites engineer their own ecosystem

The Namib Desert is dotted with thousands of mysterious “fairy circles,” which are near-perfect circles of barren soil two to fifteen meters wide, rimmed by tall grass. They are unmistakable and stretch for miles, giving the landscape an ethereal and otherworldly feel. Many possible explanations have been proposed, including toxic substances in the soil, meteorites, termites, UFOs, and the ghosts of dead natives. But the circles are extremely remote—more than 110 miles from the nearest village—and have been difficult to study scientifically. Despite decades of research, the cause of these bizarre circles has remained elusive.

But now, after a six-year study and more than 40 trips to the Namib Desert, Dr. Norbert Juergens believes he has come to understand the biological underpinnings of this strange phenomenon. According to Juergens, a single species of termites is responsible for creating and maintaining the circles. But the barren circles aren't just a byproduct of these tiny insects living below the sandy desert surface; they are part of a carefully cultivated landscape that helps the termites—and many other organisms—thrive in an otherwise inhospitable climate.

Juergens hypothesized that if the fairy circles’ cause was biological, the organism would need to co-occur with the circles and would probably not be found elsewhere. Only one species fit the bill: Psammotermes allocerus, the sand termite. Not only was the sand termite the only insect species that lived across the entire range of the fairy circles, but these termites were found to be living beneath nearly every circle sampled. And the harder the termites worked – foraging, burrowing, and dumping their refuse – the more grass died, leading Juergens to conclude that the termites keep the circles barren by burrowing underground and foraging on the roots of germinating grasses.

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Action-packed video games may help dyslexic kids learn to read

For children with dyslexia, learning to read can be a nightmare: to them, it's a jumble of words, letters, and sounds that is impossible to make sense of. Studies show that dyslexia is a disorder of the brain (rather than of the visual system), but since scientists still don’t know the root cause, there’s no simple way to combat the disorder. Traditional treatments and therapies for the dyslexia are time-consuming, expensive, and don’t necessarily bring huge improvements.

One of the hallmarks of dyslexia is what researchers call "attentional dysfunction;" this deficit makes it hard for dyslexics to focus their attention and pick out important information in a cluttered environment. To attack this deficit head-on, a group of Italian researchers wondered whether children with dyslexia would benefit from intense immersion in an activity that forced them to practice these skills. Specifically, would playing active video games help dyslexic kids learn to focus their attention, making it easier for them to learn to read?

The answer was a resounding yes, according to the research detailed in Current Biology this week.

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Mass whale strandings aren’t all in the family

Each year, more than a thousand marine mammals die during mass strandings, which are grisly events in which large numbers of whales or dolphins become beached on the shore together. But scientists still don’t know exactly why these strandings occur. Climatic events, unfamiliar underwater topography, and noise from seismic surveys and naval exercises have all been suggested to play a role. In another theory based on family ties, one or a few whales, driven by disease or starvation, veer off in the wrong direction and draw well-meaning family members into shallow, dangerous waters as they try to help.

However, a paper in this week’s Journal of Heredity suggests that the role of relatives in mass strandings may not be quite so straightforward.

The researchers collected skin samples and information about the spatial distribution of 490 long-finned pilot whales stranded in 12 events across New Zealand and Tanzania. By studying the whales’ mitochondrial DNA (a type of genetic information passed on from mother to offspring), the researchers could determine how closely-related the stranded animals were.

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