Image: Dustin Quasar

There are a lot of reasons to think twice before getting something permanently drawn on your body. One is that people still treat those with tattoos differently than those without. One recent study, for instance, looked at how men treat women with tattoos. What they found was that men are more likely to approach a woman with a tattoo and more likely to expect a date or sex with that woman.

Here’s how the study worked. Researchers had women place temporary tattoos on their lower backs and sent them to a well-known beach. The women were instructed to lay on the beach reading a book, staying on their stomachs so that the tattoo was visible. There were two parts to this study. In the first one, once the woman was in place, researchers watched and counted how many men approached her. In the second, once the woman assumed her position, a male researcher walked around the beach and asked random men whether they would be willing to “respond to three questions about a girl somewhere on the beach.” Every single man they approached said yes.

Here’s how the researchers summarized their results:

Two experiments were conducted. The first experiment showed that more men (N = 220) approached the tattooed confederates and that the mean latency of their approach was quicker. A second experiment showed that men (N = 440) estimated to have more chances to have a date and to have sex on the first date with tattooed confederates.

Interestingly, the study did refute an earlier finding about women with tattoos. In 2007, researchers from the University of Liverpool showed that men rated women with tattoos as physically less attractive, but sexually more promiscuous than those without. In this study, researchers found that physical attractiveness—as rated by the men on the beach who agreed to answer questions about the woman—wasn’t impacted by the tattoo. Another study in 2005 also found that tattoos don’t change attractiveness, but do negatively impact a person’s credibility, regardless of their gender.

So tattoos might not be bad for picking up dudes at the beach, but they might impact what those dudes think of you in the long run.

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A Scottish wildcat. Photo: Peter Trimming

Scottish wildcats, the U.K.’s only remaining species of wild feline, look a little bit like adorable grey tabbies, slightly on the large size, with a bushy striped tail. But the species lived in Scotland long before any domestic relatives—or humans—arrived. Nicknamed “the tiger of the highlands,” the felines were rumored for years to be man-killers. The Scottish Wildcats Association makes clear that these fierce felines are no cuddly kittens:

Although classically portrayed as a ferocious and terrifying beast to be feared and hated, wildcats simply enjoy their personal space, daily schedule and peace. A wildcat will only attack something it’s hunting, or something that it feel is hunting it. When threatened their classic strategy is to turn on an aggressor hissing, growling and spitting furiously; just like a domestic cat their hackles raise and the back arches but rather than turn side on to try and look big, they mock charge like a big cat; stamping forwards at you hissing and spitting. The idea is to give you just enough doubt to give them an opportunity to escape. If given no other choice and in fear of its life, perhaps cornered or defending kittens, the cat will attack with all its fury.

Yet only about 100 of the wildcats remain, and researchers point to the common house cat as the main culprit behind the species’ demise, the BBC reports. Wildcats and house cats, it turns out, are interbreeding, and scientists project the species could be obliterated by house cat genes within two years.   

Paul O’Donoghue, a researcher calling for the species’ conservation, compared the 63,000 domestic cat genes to those of the wildcats. He combed through 140 years worth of wildcat specimens kept in London and Edinburgh museums in order to find pristine genetic samples, then compared those two standards to samples attained from wildcats in the wild.

O’Donoghue concluded that extinction due to hybridization is almost guaranteed, perhaps within two years, for the wildcat unless conservationists undertake drastic action. For him, that means trapping the wildcats that still maintain pure genes, breeding them, and perhaps even placing them in the care of volunteers—so long, of course, as there are no frisky house cats about.

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Image: Svenstorm

It’s a common mantra: in order to live a long healthy life, you must eat well and exercise. Extra pounds are extra years off your life, we hear. Your annoying aunt might believe this with her heart and soul. But the science isn’t so sure.

Today in Nature, reporter Virginia Hughes explained that there’s a lot of research suggesting that being overweight doesn’t always mean you life a shorter life. This is what many call the obesity paradox. Hughes explains:

Being overweight increases a person’s risk of diabetes, heart disease, cancer and many other chronic illnesses. But these studies suggest that for some people — particularly those who are middle-aged or older, or already sick — a bit of extra weight is not particularly harmful, and may even be helpful. (Being so overweight as to be classed obese, however, is almost always associated with poor health outcomes.)

This paradox makes public health campaigns far trickier. If the truth was at one extreme or the other—that being overweight either was or was not good for you—it would be easy. But having a complicated set of risks and rewards doesn’t make for a good poster. And public health experts really do want most people to lose weight and not put on extra pounds.

This is where researchers, public health policymakers and campaigners are starting to butt heads. A simple message—that fat is bad—is easier to communicate. But the science just isn’t that simple.

When a researcher from the CDC put out a study that suggested that excess weight actually extended life, public health advocates fired back, organizing lectures and symposia to take down the study. Katherine Flegal, the lead researcher on that study, says she was surprised by just how loud the outcry was. “Particularly initially, there were a lot of misunderstandings and confusion about our findings, and trying to clear those up was time-consuming and somewhat difficult,” she told Hughes. But the study was a meta-review, a look at a large group of studies that investigated weight and mortality. The research is there, Flegals says, and it suggests that weight isn’t necessarily the worst thing for you. And for Flegal, what public health people do with her work isn’t really that important to her. “I work for a federal statistical agency,” she told Hughes. “Our job is not to make policy, it’s to provide accurate information to guide policy-makers and other people who are interested in these topics.” Her data, she says, are “not intended to have a message”.

And the fight against fat hasn’t really ever been particularly effective. Not a single obesity drug or diet plan has been proven to last over a year, says Hughes in a blog. And much of our weight comes down to genes, she writes:

Friedman sees things quite differently, as he eloquently explained in a 2003 commentary in Science. Each of us, he argues, has a different genetic predisposition to obesity, shaped over thousands of years of evolution by a changing and unpredictable food supply. In modern times, most people don’t have to deal with that nutritional uncertainty; we have access to as much food as we want and we take advantage of it. In this context, some individuals’ genetic make-up causes them to put on weight — perhaps because of a leptin insensitivity, say, or some other biological mechanism.

So those who are the most prone to obesity might have the least ability to do anything about it. We’re not particularly good at understanding obesity and weight yet. Some of the key metrics that we use to study weight aren’t particularly good. Body Mass Index has long been criticized as a mechanism for understanding health. Dr. Jen Gunter blogged about Flegals’s study when it came out (she was critical of it) and explained why BMI might be the wrong tool to use to look at mortality:

BMI just looks at weight, not the proportion of weight that is muscle mass vs. fatty tissue. Many people with a normal BMI have very little muscle mass and thus are carrying around excess fat and are less healthy than their BMI suggests. There are better metrics to look at mortality risk for people who have a BMI in the 18.5-34.9 range, such as waist circumference, resting heart rate, fasting glucose, leptin levels, and even DXA scans (just to name a few). The problem is that not all these measurement tools are practical on a large-scale.

And while researchers argue over whether weight really does guarantee a shorter life and policy advocates try to figure out what to advocate, the weight loss industry rakes in billions of dollars every year playing to our fears and uncertainties.

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Photo: NOAA

Climate change is making the world warmer and, in many places, dryer, setting the stage for increased forest fire activity across the country. In a new study, scientists with the U.S. Department of Agriculture’s Forest Service say that the amount of land affected by forest fires in the U.S. is expected to increase by at least 50 percent but maybe as much as 100 percent by 2050—a doubling of burned area within less than 40 years.

In the study, led by meteorologist Yongqianq Liu, the researchers say that, more than just responding to a warming world, forest fires actually stoke themselves over the long term. By releasing carbon dioxide to the atmosphere, forest fires increase the likelihood of future fires. According to earlier research forest fires account for about a third of global carbon dioxide emissions. Some of this carbon dioxide will eventually get pulled back out of the atmosphere by plants regrowing in the burned region. But in the short term, say the scientists, the carbon dioxide is an important part of the amplified greenhouse effect.

According to the study, smoke streaming from fires can actually make the area under the cloud colder, because smoke in the air reflects sunlight. That might seem like a silver lining to the ash cloud. But the smoke also suppresses rain, increasing the potential for drought. So, really, it’s not much of a silver lining after all.

In the end, the scientists say that climate change is going to make forest fires worse, and it seems that the fires themselves will encourage this trend.

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Photo: SKopp

Editors at academic journals often receive random manuscripts claiming to have figured out the mysteries of the universe or solved fundamental puzzles in mathematics or physics. But when the editorial team of the Annals of Mathematics, one of the field’s most respected publications, took a look at a manuscript submitted by an obscure lecturer from the University of New Hampshire, the Simons Foundation reports, they realized this was something significant. Yitang Zhang, the author, had tackled one of mathematic’s oldest problems: the twin primes conjecture.

The New Scientist gives some background:

A number is prime if you can’t divide it by anything but 1 and itself. Twin primes are primes that are only two numbers apart – like 3 and 5, 5 and 7, and 11 and 13. The largest known twin primes are 3,756,801,695,685 × 2^666,669 + 1 and 3,756,801,695,685 × 2^666,669 - 1, and were discovered in 2011.

The twin prime conjecture states simply that there are an infinite number of these twin primes. Although simple in its concept, a proof of it has been stumping mathematicians since the idea was proposed in 1849 by French mathematician Alphonse de Polignac.

While vacationing at a friend’s home last summer, Zhang had an ah-ha! moment. He had noticed an overlooked technical detail that led him to his proof. He was able to show that there is an infinite number of prime pairs separated by a measurable finite distance. In other words, there’s a limit to how far away primes can get from each other. The New Scientist writes:

Unfortunately for lonely primes, that distance is still quite large: 70 million. But Zhang stresses that this is an upper bound.

“These values are very rough,” he says. “I think to reduce them to less than one million or even smaller is very possible” – although mathematicians may need another breakthrough to reduce the distance all the way down to just 2 and finally prove the twin prime conjecture.

What matters is that Zhang was able to show that the gap between adjacent primes cannot exceed a certain value.

As the Simons Foundation writes, Zhang really did come out of no where. He attended Purdue, but after graduation struggled to find a job in academia and even worked at Subway for a while.

“Basically, no one knows him,” said Andrew Granville, a number theorist at the Université de Montréal. “Now, suddenly, he has proved one of the great results in the history of number theory.”

In some ways, that’s the most surprising parts of this story. In mathematics, the age limit for genius discoveries is supposed to be about 30. Slate wrote about this assumption back in 2003:

It’s not hard to see where the stereotype comes from; the history of mathematics is strewn with brilliant young corpses. Evariste Galois, Gotthold Eisenstein, and Niels Abel—mathematicians of such rare importance that their names, like Kafka’s, have become adjectives—were all dead by 30. Galois laid down the foundations of modern algebra as a teenager, with enough spare time left over to become a well-known political radical, serve a nine-month jail sentence, and launch an affair with the prison medic’s daughter; in connection with this last, he was killed in a duel at the age of 21. The British number theorist G.H. Hardy, in A Mathematician’s Apology, one of the most widely read books about the nature and practice of mathematics, famously wrote: “No mathematician should ever allow himself to forget that mathematics, more than any other art or science, is a young man’s game.”

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A rhinovirus. Photo: RobinS

For years, researchers have struggled to discern whether temperature has anything to do with normal seasonal fluctuations in viruses—what the cold has to do with catching colds. And according to new research, Nature News reports, the old wives’ tale that the chilly winter air promotes sickness does turn out to be founded in fact.

Rhinoviruses cause the common cold and are the culprits behind most seasonal ailments. Lower temperatures, researchers from Yale University found, suppress the immune system’s ability to fight off these viruses in both mice and human airway cells.

In an attempt to solve the cold conundrum, Foxman and her colleagues studied mice susceptible to a mouse-specific rhinovirus. They discovered that at warmer temperatures, animals infected with the rhinovirus produced a burst of antiviral immune signals, which activated natural defenses that fought off the virus. But at cooler temperatures, the mice produced fewer antiviral signals and the infection could persist.

Humans likely follow the same patterns. The researchers grew human airway cells in the lab, then exposed them to rhinoviruses under different temperatures. Like the mice, the cells kept at a warm temperature were more likely to fend off the virus by undergoing programmed cell death, which limits the replicating virus’ spread throughout the body.

Thus, colds proliferate in winter when temperatures drop and cold air chills people’s upper respiratory tracts, giving the rhinovirus a chance to strike. While your parents were right to advise you to bundle up, the researchers point out to Nature that in science, nothing is ever so simple, and temperature is likely to be just one of several factors promoting colds in the wintertime.

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Dawww. Photo: aaronz

Yellowstone National Park is a vast expanse of largely-untouched natural beauty, a tract of the west home to bears and wolves and geysers and mountains. But where humankind’s direct influence is deliberately kept to a minimum, that strategy of do-no-harm doesn’t always seem to work. For the past few decades, lake trout have been taking over the rivers and lakes in Yellowstone, pushing out the local Yellowstone Cutthroat trout. The Greater Yellowstone Coalition:

Yellowstone Lake and its tributaries once supported an estimated 3.5 million Yellowstone cutthroat trout. Since the illegal introduction of lake trout in the 1980s, the cutthroat population in Yellowstone Lake has plummeted. Catch rates for Yellowstone cutthroats have significantly dropped as more and more lake trout are caught every year. The precipitous drop in cutthroat numbers is a result of lake trout predating on cutthroat trout.

But more than just affecting cutthroat trout, the invasion of the lake trout is being felt throughout the ecosystem. According to new research lead by Yale’s Arthur Middleton, the replacement of cutthroat trout with lake trout is leaving Yellowstone’s local population of grizzly bears without enough fish to eat. Middleton and colleagues:

Historically, Yellowstone Lake harboured an abundant population of cutthroat trout, but lake trout prey heavily on cutthroat trout and have driven a decline of more than 90 per cent in their numbers. Although cutthroat trout migrate up shallow tributary streams to spawn, and are exploited by many terrestrial predators, lake trout spawn on the lake bottom and are inaccessible to those predators.

Without fish, the grizzlies need something, and in their place the bears have turned to eating baby elk.

In the late 1980s, grizzly and black bears killed an estimated 12 per cent of the elk calves in northern Yellowstone annually. By the mid-2000s, bears were estimated to kill 41 per cent of calves.

The researchers say that by turning to elk calves in place of the now-gone trout, the elk population growth rate has shrunk by 2 to as much as 11 percent. The research reminds that the food web is in fact a web, and that the illegal introduction of a few trout can mean a whole lot of dead elk.

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Photo: Jack

As a patient, dealing with the anxiety of waiting to get poked with a needle may be no fun at all. But it’s actually a positive behavior. In trials with mice, stress boosted the immune system, a team of Stanford University researchers found, making it vaccines more effective. Ferris Jabr reports for Scientific American:

Mice that were stressed out prior to their inoculations had an easier time overcoming a subsequent infection than mice that the researchers left in peace before their shots.

Something similar seems to happen to people. In a study of knee surgery patients, for example, Dhabhar and his teammates found that anticipating surgery increases the number of immune cells circulating in the bloodstream in the days preceding the operation.

While stress is generally thought of in terms of its negative effects, researchers are beginning to distinguish between two different types of stress. Chronic stress, suffered over a long period of time, can cause harm, whereas acute stress, like visiting the doctor or racing to meet a deadline, may actually make us stronger and healthier.

From an evolutionary perspective, the fact that short-term stress revs up the immune system makes sense. Consider a gazelle fleeing a lioness. Once the gazelle’s eyes and ears alert its brain to the threat, certain brain regions immediately activate the famous fight-or-flight response, sending electrical signals along the nervous system to the muscles and many other organs, including the endocrine glands—the body’s hormone factories. Levels of cortisol, epinephrine, adrenaline and noradrenaline rapidly increase; the heart beats faster; and enzymes race to convert glucose and fatty acids into energy for cells. All these swift biological changes give the gazelle the best chance of escape.

The brain also responds to stress by priming the immune system to prepare for a potential injury. This may explain why people and mice more readily respond to vaccines when they’re stressed out. So cry all you’d like in the waiting room – you may be doing your body a favor in the long run.

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Photo: stefanpinto

In the animal kingdom, larger males—think chimpanzees, lions, bulls—often try to acquire or defend more resources, like territory, food, and females, than their weaker underlings. Researchers decided to apply the competitive animal model to human political decision making about redistribution of wealth and income to see if there was any correlation.

The Atlantic describes the study:

Researchers at Aarhus University in Denmark and UC Santa Barbara collected from several hundred men and women in Argentina, the U.S., and Denmark. They categorized the subjects by socioeconomic class, their upper-body strength, or “fighting ability” (as measured by the “circumference of the flexed bicep of the dominant arm”), and their responses to a questionnaire gauging their support for economic redistribution.

They hypothesized that men with more upper body strength would be less open to wealth distribution, following the same tendency of stronger males of many animal species. After all, upper-body strength has counted as a major component of dominance throughout human evolutionary history. When economics, strength and gender were taking into account, that hypothesis turned out to be true. Popular Science reports:

Socioeconomic status also showed a correlation with economic views. As expected, rich men were generally opposed to redistribution, and poor men generally in favor of it. Men with stronger upper bodies tended to have stronger views–rich, strong men were very much opposed to redistribution, while less strong but still rich men were less opposed. On the side of those that support redistribution, the trend was reversed: poorer but strong men were strongly in favor of redistribution, while weaker poor men were not as committed.

Political party had nothing to do with the results, the researchers found, and no correlation turned up between women’s opinion on the subjet and their physical strength and/or wealth.

The authors conclude: “Because personal upper-body strength is irrelevant to payoffs from economic policies in modern mass democracies, the continuing role of strength suggests that modern political decision making is shaped by an evolved psychology designed for small-scale groups.”

For many men, apparently, animal antics still hold strong.

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Photo: Timmarec

In Croatia, scientists are working on a new way to detect land mines without risking lives, reports the Associated Press. Honeybees, the scientists say, have an incredible sense of smell, and with the right amount of prodding can be trained to sniff out TNT, the most common explosive used in land mines. In preliminary testing:

Several feeding points were set up on the ground around the tent, but only a few have TNT particles in them. The method of training the bees by authenticating the scent of explosives with the food they eat appears to work: bees gather mainly at the pots containing a sugar solution mixed with TNT, and not the ones that have a different smell.

A common technique in animal behavior training, the bees are taught to associate the smell of TNT with food. Once that association is firm, the bees can be turned loose in search of mines.

”It is not a problem for a bee to learn the smell of an explosive, which it can then search,” Kezic said. “You can train a bee, but training their colony of thousands becomes a problem.”

Bees, with their incredible sense of smell, light weight and ability to fly should be better candidates for mine hunting than other approaches. Mine decommissioning teams already use dogs and rats to hunt down mines. But, some anti-personnel mines are so sensitive that the weight of a pup can set them off. The bees’ training is still underway, says the AP, but if and when they’re ready the Croatian-trained bees will be able to flit from mine to mine without setting them off.

From 1999 to 2008, says the Guardian, 73,576 people reportedly died to hidden land mines or unexploded munitions. “Of these, around 18,000 were confirmed deaths – 71% of victims were civilians and 32% were children.” Aside from their destructive potential, land mines are also a psychological and social plight.

Landmines and cluster munitions have been described as “weapons of social cataclysm”, which perpetuate poverty and prevent development. They leave a legacy of indiscriminate civilian injuries and deaths, burden struggling healthcare systems and render vast tracts of land uninhabitable and unproductive. As Kate Wiggans, from the International Campaign to Ban Landmines and Cluster Munition Coalition (ICBL-CMC) says: “They keep poor people poor, decades after conflict.”

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Weee, feces! Photo: Jtu

The public pool may as well be renamed the public poo. The Centers for Disease Control and Prevention recently announced that the majority of public swimming holes have feces in them—brought to the pool on people’s unwashed skin or deposited by those who lack self-control. And along with fecal matter come illness-inducing bacteria.

Last year, the CDC tested the water from 161 public pools around Atlanta, where the CDC’s main offices are located. In 95 of them, or 58 percent, they found the bacteria Pseudomonas aeruginosa, a bacteria that causes rashes or ear infections. In 59 percent of pools they found E. coli, another sign that feces had been in the water. The CDC puts it delicately:

Fecal material can be introduced when it washes off of swimmers’ bodies or through a formed or diarrheal fecal incident in the water. The risk for pathogen transmission increases if swimmers introduce diarrheal feces.

Though the CDC only tested pools in Atlanta, they’re pretty sure that the results apply to the whole country. As the CDC tells the Associated Press, outbreaks of diarrhea are common across the country. Along with taking a pre-swim shower, the health agency wants to remind you that it’s probably a good idea to not drink the water.

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Electrocardiograms, or ECGs, track the heart’s electrical activity through electrodes on the body. Photo: Mass Communication Specialist 2nd Class Gary Granger Jr./U.S. Navy

When you’re having a heart attack, every second counts. The tightness in your chest intensifies with each passing minute. The clotting blood in your coronary artery, blocked by plaque, steadily builds up. Deprived of oxygen-rich blood, parts of your heart muscle soon slowly begin to die. If surgeons don’t remove the blockage and restore blood flow in time, the clock runs out.

The faster a patient gets treatment, the better. That’s why many EMTs have started using smartphones to email hospitals pictures of electrocardiogram results—paper readouts of the patient’s heartbeat—while they’re still in the ambulance. But emails often take more than a few minutes to reach awaiting doctors, and an error message about a too-big file is the last thing first responders want to see.

To speed treatment, researchers at the University of Virginia bypassed email altogether. They have developed a smartphone app that transmits pictures of ECGs to hospitals in a matter of seconds. They presented their work this morning at the annual American Heart Association’s Quality of Care and Outcomes Research Scientific Sessions in Baltimore.

The team hopes the app will save the lives of patients suffering from a particular type of heart attack that causes heart muscle to die with the passage of time. During this type of attack—ST-segment elevation myocardial infarction, or STEMI—victims’ chances of dying increase by 7.5 percent with every 30 minutes they don’t receive treatment. Doctors can spot signs of a STEMI by studying the squiggly lines of an electrocardiogram printout, which shows the heart’s electrical activity and any of its irregularities.

To get this live-saving document to the emergency room, EMS personnel snap a photo of it with the app using an iPhone camera. The app, designed to maintain high-resolution quality, then compresses it to approximately 32 kilobytes. That’s a pretty small file: you could fit about 62,500 of them on a standard 2-gigabyte flash drive. Once the image has been shrunk, it’s divided into 16 parts, which are sent to the receiving hospital’s server over standard cellphone networks. There, the pieces are reassembled to form a complete image, which doctors can look at it in full using an online interface on their computers.

In 1,500 trials in the Charlottesville area, more than 95 percent of transmissions made it to the hospital in less than 25 seconds. The app consistently outperformed email, whether the cellphone network used was Verizon, Sprint or AT&T. Images were transmitted in four to six seconds, compared to 38 to 114 seconds for actual-size image files.

Both the app and email transfer times slowed when initial picture sizes were bigger or cellphone service petered out, but the STEMI app photo still reached hospital servers first. The trials showed the app had a failure rate of less than .5 percent, while rates for email ranged from 3 percent to 71 percent, depending on the network provider. Next, the researchers hope to test the STEMI app in rural areas, where cellphone service tends to be hard to find.

Mobile technology is making its way steadily into health care: it’s becoming common, for instance, for doctors and nurses to track patient charts on iPads. While the technology has been shown to improve physicians’ work flow, reports also suggest these tools can be a dangerous distraction. But in the field of medicine, most health care professionals can agree that faster emergency treatment, with or without the help of an iPhone, is always better.

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Math haters: If slight electric shocks to your brain would improve your ability to crunch numbers, would you do it? Alternatively, would you sign your child up to undergo this treatment if it meant better grades in algebra class? If new research published in Current Biology pans out, those of us who are not mathematically gifted may someday face these questions. The Guardian reports:

Psychologists at Oxford University found that students scored higher on mental arithmetic tasks after a five-day course of brain stimulation.

If future studies prove that it works – and is safe – the cheap and non-invasive procedure might be used routinely to boost the cognitive power of those who fall behind in maths, the scientists said. Researchers led by Roi Cohen Kadosh zapped students’ brains with a technique called transcranial random noise stimulation (TRNS) while they performed simple calculations, or tried to remember mathematical facts by rote learning.

Twenty-five students received these “gentle” brain shocks, and 26 served as control students, though they believed they were receiving treatment, the Guardian continues. Those who received the real treatment completed math questions 27 percent faster than those who received the placebo, the researchers reported in their paper.

ScienceNOW points out that, while this may sound extreme, electroshock treatment finds use in a range of medical applications:

The idea of using electrical current to alter brain activity is nothing new—electroshock therapy, which induces seizures for therapeutic effect, is probably the best known and most dramatic example. In recent years, however, a slew of studies has shown that much milder electrical stimulation applied to targeted regions of the brain can dramatically accelerate learning in a wide range of tasks, from marksmanship to speech rehabilitation after stroke.

In this latest study, the researchers additionally claimed that at least six of the students who returned to the lab for further testing still enjoyed the mathematical benefits of their treatment six months after it was administered. Other researchers told the Guardian, however, that six is a very small sample number so should not be counted as definitive evidence, so more thorough follow-ups will be needed to confirm that observation.

Even though the amount of electricity used in this study—1 milliamp, just a fraction of the voltage of an AA battery—is very small, ScienceNOW writes, there could be unintended side effects, so researchers discourage overenthusiastic parents from trying the technique at home.

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A crazy ant queen. Photo: Joe MacGown, Mississippi Entomological Museum

Since fire ants first invaded the U.S. through cargo ships docking in Mobile, Alabama, the aggressive pest has taken a firm hold in the South and Southwest. More than $5 billion is spent each year on medical treatment and fire ant control, according to Food and Drug Administration, and the ants cost an additional $750 million in agricultural damage.

Now, however, there’s a new ant on the block. The crazy ant – also an invader from South America – is displacing fire ants in the U.S. by gobbling them up. But this unprescribed cure is likely worse than the disease it’s treating. The Los Angeles Times reports:

Like fire ants, these South American invaders seem to be fond of electrical equipment. But unlike their stinging red counterparts, the tawny crazy ants create mega-colonies, sometimes in homes, and push out local populations of ants and arthropods.

Thus  far, the crazy ants are not falling for the traditional poisons used to eliminate fire ant mounds. And when local mounds are destroyed manually, they are quickly regenerated.

Though the crazy ants don’t deliver the same burning bite as fire ants, they do stubbornly make their nests in bathroom plumbing or in walls. So far, researchers haven’t documented any native animals preying on the crazy ants, so their colonies are allowed to run amok, sometimes growing 100 times the size of other species of ants living in the area.

This isn’t the first time one ant invader has been displaced by another. The Argentine ant arrived back in 1891, followed by the black ant in 1918. But the fire ant put an end to those two invasive species when it arrived a couple decades later. Now, the fire ant’s own day of invasive reckoning may have arrived, but rather than feel relieved, researches are worried. Southern ecosystems have had time to adjust to fire ants. Crazy ants—well, who knows what they’ll do?

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Photo: muffet

Pregnancy tests did not always come in an easy-to-use, sterile kit that provided almost immediate results. Less than a century ago, women had to rely upon frogs instead. In 1938, Dr. Edward R. Elkan wrote in the British Medical Journal:

The discovery of what is now known as the xenopus pregnancy test is based on experiments conducted by Hogben (1930, 1931), who observed that hypophysectomy produced ovarian retrogression, and the injection of anterior pituitary extracts ovulation, in the female South African clawed toad.

The African clawed frog, as its better known today, was imported around the world for its use in pregnancy tests. Doctors would ship urine samples to frog labs, where technicians would inject female frogs with a bit of the urine into their hind leg. The animals would be placed back into their tanks, and in the morning the technicians would check for tell-tale frog eggs dotting the water. If the female frog had ovulated, that meant the woman who provided the urine was pregnant and the pregnancy hormone, human chorionic gonadotropin, had kicked off ovulation in the frog. Researchers referred to this procedure as the Hogben test.

Among the 295 tests which I have done so far and in which 2,112 frogs were used I have not seen one clear positive that did not indicate a pregnancy. There were a few negative results which when repeated after a fortnight became positive, but I do not think that these can be regarded as failures.

Frogs were actually a great improvement on the previous means of testing whether or not a woman was pregnant.   Welcome History describes:

Prior to Xenopus, female mice and rabbits had been used, but these had to be slaughtered, dissected and carefully examined for ovarian changes. Because toads were reusable and could be conveniently kept in aquaria, Xenopus made pregnancy testing practical on a larger scale than before.

Thousands of the frogs were exported across the world from the 1930s to 1950s for use as pregnancy testers.

Immunological test kits finally replaced Xenopus in the 1960s and were rapidly taken up by private companies and feminist organisations offering diagnostic services directly to women. The first over-the-counter home test was sold in pharmacies in the early 1970s, but it resembled a small chemistry set and so was not user-friendly. It was not until 1988 that the first recognisably ‘modern’ one-step-stick hit the shelves.

But the frogs’ legacy lives on. African clawed frogs can be found living around many urban centers today, where they were likely released into the wild after hospitals no longer had use for them. Additionally, the imported frogs are common pets, and no doubt some of those pets wear out their welcome and get chucked into a local stream or pond.

In 2006, researchers realized that the frog may be carriers for the deadly amphibian chytrid fungus, which has caused the extinction and decline of around 200 amphibian species around the world. Now, research published in PLoS One shows for the first time that populations of African clawed frogs living in California carry the fungus. The frogs can carry the disease for long periods without being affected themselves, so researchers suspect that they may be the original vectors that introduced the fungus around the world—a sort of revenge for being used as egg-laying research subjects for all those years.

More from Smithsonian.com:

Three New Frog Species Face an Uncertain Future  
Crayfish Have Been Secretly Spreading a Deadly Frog Epidemic