Science-- there's something for everyone

Friday, June 28, 2013

Where’s the best place to meet your future spouse?

John Cacioppo from the University of Chicago and his colleagues interviewed over 19,000 Americans who married between 2005 and 2012 to find out where they first met their future spouse and how satisfied they were as a couple. You may be surprised to learn that meeting online was somewhat better than meeting in person.

Just over a third of the respondents had met their spouse online. It turned out that these people had a slightly lower breakup rate (divorce or separation) than people who met ‘off-line’ (at work, church, school, etc). Even more interesting, people who had met their spouses online reported greater marital satisfaction.

One thing to keep in mind: not all online venues are the same. Older participants were more likely to have used email, whereas younger people tended to meet each other through social networks and virtual worlds. How did these compare? 

If marital satisfaction is your goal, then the best place to meet your spouse online is at eHarmony. This might be a good place to note that this study was sponsored by eHarmony. That doesn't necessarily invalidate the results, but it's something to keep in mind. Other online dating sites were also very good (except for Yahoo, which for some reason led to abysmal marital satisfaction rates). That’s good news because nearly half the participants who met their spouses online did so via a dating site. If you’re not into online dating sites, your next best bet is to meet someone in a multiplayer game or a social network. Sorry, older participants, but email was only a mediocre way to meet someone. Whatever you do, don’t try to meet someone in a chat room.

Off-line meetings weren’t all alike either. Your best chance of marital happiness comes from marrying someone you meet at school, a place of worship or at social gatherings. People who met through work or at bars didn’t fare as well, and blind dates were the worst. As far as your future marital satisfaction is concerned, you can tell your mother that meeting through family was also at the bottom, though marrying someone you grew up with was at the very top.

The researchers did not evaluate why some venues were better than others. Obviously, there are happy couples who met in all sorts of places, even through Yahoo. However, it’s clear that there should be no stigma attached to trying to meet someone online. If anything, you may improve your chances at future happiness by doing so.

Cacioppo, J., Cacioppo, S., Gonzaga, G., Ogburn, E., & VanderWeele, T. (2013). Marital satisfaction and break-ups differ across on-line and off-line meeting venues Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1222447110.

Thursday, June 27, 2013

A mother’s gastric bypass affects her future children

Not long ago, I wrote a post explaining why gastric bypass is such an effective weight loss strategy. It seems that the procedure alters the microbial content of the subjects’ guts. Apparently, that’s not all that gets altered.

Frédéric Guénard of Laval University and his colleagues compared twenty-five kids who were born before their mothers underwent gastric bypass surgery (group 1) to twenty-five of their siblings born after the surgery (group 2). Genetic testing showed that close to 6000 genes were methylated differently between the two groups of children and that those differences were responsible for differences in gene expression. 

Let me repeat that: an action of a woman (undergoing bypass surgery) can alter gene expression in her children born years later.

This image shows a DNA molecule that is methylated on both strands on the center cytosine.
Created by Christoph Bock (Max Planck Institute for Informatics) 2/18/2006.

The changes in methylation between groups 1 and 2 were not random. The affected genes were predominantly ones involved in insulin sensitivity, metabolism and vascular disease. Sure enough, the kids in group 2 had less obesity and lower blood pressure, and were less prone to autoimmune or vascular disease or diabetes.

To be clear, the scientists haven’t established that gastric bypass surgery itself leads directly to having offspring with an altered methylation pattern. The difference could have resulted simply from changes in body composition or eating habits in the mother, or from the altered microbial environment around the womb. But one way or another, the gestational environment of kids does appear to affect them profoundly. 

If you’re a woman with your reproductive years ahead of you who didn’t already have enough to worry about, you’re welcome.

Guénard, F., Deshaies, Y., Cianflone, K., Kral, J., Marceau, P., & Vohl, M. (2013). Differential methylation in glucoregulatory genes of offspring born before vs. after maternal gastrointestinal bypass surgery Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1216959110.

Wednesday, June 26, 2013

Just for fun: Nano sculptures

This beautiful flower is actually a tiny crystal (about 50 microns across) that was coaxed into forming these delicate shapes by manipulating the temperature, acidity and carbon dioxide level of the water in which it was grown.


Spiky flowers grown on a base of budded globs show off the researchers’ ability to design complex forms using this new technique. 

Wim L. Noorduin, Harvard School of Engineering and Applied Sciences

You can see the rest of the slideshow here. The images were originally in black and white, by the way. The colors were added later. At first, I was disappointed to read that, but then I realized that it's really the shapes that are amazing.

Tuesday, June 25, 2013

Do dogs need a secure base?

Children look to their parents for security and for cues about how to react. Not only do children resist separation from their caretakers, but they also use those caretakers as a ‘secure base’ from which to explore their environments. Do dogs do the same thing with their owners? That’s the burning question addressed by Lisa Horn, Ludwig Huber and Friederike Range of the University of Vienna (and also from the Clever Dog Lab Society, which has to be the world’s greatest place to work).

Most young children are more willing to explore their environment, play with toys or tackle problem-solving tasks when their parents are close by. Like young children, dogs are wholly reliant on the adult humans around them. To test whether dogs also use their owners as a secure exploration base, the researchers presented the dogs with food-hiding toys under three experimental conditions: the owner was absent, the owner was present but blindfolded and thus did not engage with the dog at all (silent), or the owner was present and encouraging the dog to interact with the toy. Only by persistently manipulating the toy (apparatus) with their paws and mouth could the dog gain access to the food treat. 

You can see the set up here:

Figure 2 Schematic representation of the experimental set-up.
At the beginning of each trial, the dog was released by the experimenter from the release point, which was 2.5 m away from the toy. During each trial the experimenter stood on the right side of door 1 – timing the trial with a clock on the opposite wall. The owner either sat on the designated chair on the left side of door 1 or was in the adjacent room. 

Dogs were coded for time spent manipulating the toy (though not for successfully prizing the food out of it--this wasn’t a test for skill or intelligence) and time spent in proximity to either owner or experimenter (marked as having its head and at least one paw within the dotted lines).

Here were the results:

Figure 3 Duration of manipulating the apparatus –

It’s not surprising that the dogs worked on the toy puzzles longer when their owners were actively encouraging them to do so. But notice that the difference between the ‘silent’ and ‘encouraging’ owners wasn’t nearly as great as the differences between those conditions and the ones with the absent owners. Dogs also spent far more time close to the experimenter (who completely ignored the dogs and only watched the clock) when their owners were absent.

This seems like a clear indication that dogs are using their owners as secure bases for exploration. Except for one thing. Look what happens when the researchers substituted a blind-folded stranger (replaced owner) for the owner.

Figure 5 Duration of manipulating the apparatus –

As you can see, when a silent stranger took the owners’ place in the experiment, the dogs spent an intermediate amount of time manipulating the toy. Thus, the dogs showed a range of behaviors, displaying the least confidence when no one was in the chair and the most confidence when their own owners were encouraging them to keep interacting with the toy.

This could mean that any human can more or less serve as a secure base. Or it could be that dogs don’t use secure bases in the same way that children do. In any case, the authors suggest that, going forward, other canine researchers recognize that their test subjects might be affected by the presence or absence of their owners.

Horn, L., Huber, L., & Range, F. (2013). The Importance of the Secure Base Effect for Domestic Dogs – Evidence from a Manipulative Problem-Solving Task PLoS ONE, 8 (5) DOI: 10.1371/journal.pone.0065296.

Monday, June 24, 2013

Designated driver: I do not think that word means what you think it means

Because of the dangers of driving while under the influence of alcohol, it’s a great idea to choose a non-drinking driver before you head out on town. Unfortunately, Adam Barry, Beth Chaney and Michael Stellefson from the University of Florida found that many designated drivers are not always as sober as one could wish.

The researchers hung around a college town on Friday evenings and stopped patrons exiting bars between 10 pm and 2:30 am. Participants were given alcohol breathalyzer tests and asked a few questions, including their normal drinking habits and whether they were serving as a designated driver for that evening.

Designated drivers had lower blood alcohol levels than those who were not expecting to drive. That’s the good news. The bad news is that nearly 40% of people claiming to be designated drivers had not abstained from drinking. Eighteen percent of people who were serving as their friends’ safe ride home had blood alcohol levels above 0.05. While it’s currently legal to drive in the U.S. with a blood alcohol level below 0.08, there is no doubt that a person with a blood alcohol level of 0.05 is impaired, and the National Transportation Safety Board is recommending that 0.05 be the legal limit. Even a level of 0.02 can negatively affect driving.

It seems that to many revelers, ‘designated driver’ means ‘whoever is the least intoxicated’ or maybe even, 'whoever drives the best when they're drunk' rather than ‘someone who did not consume any alcohol’. That’s not good news either for the people relying on these designated drivers or for the other cars on the road.

Barry AE, Chaney BH, & Stellefson ML (2013). Breath alcohol concentrations of designated drivers. Journal of studies on alcohol and drugs, 74 (4), 509-13 PMID: 23739013.

Friday, June 21, 2013

Is this the end of the line for the Kepler Space Telescope?

The Kepler Space Telescope has been orbiting the sun since 2009, finding exoplanets at a surprising rate. During those 14 years, the Kepler has been responsible for confirming the existence of 132 planets and for discovering over three thousand possible exoplanet candidates. It has shown us that just about every star we see in the sky has planets, many of them potentially Earth-like.

Position of the Kepler space telescope. Note, objects in this video are not to scale. 

Unfortunately, the Kepler’s planet-hunting days may be behind it.

The Kepler uses the ‘transit method’ to find exoplanets. As a planet passes in front of its star from our vantage point, we see a slight dimming of the light coming from that star. If that dimming follows a regular pattern, we have a strong suspicion that an object is orbiting the star and that the object is most likely a planet. 

The Kepler telescope monitors a single patch of sky, continuously observing the same 100,000 plus stars. In order to do that job, the Kepler is kept in position by four reaction wheels. Three wheels are necessary to control orientation in each of the three dimensions and the fourth is a redundant spare. Last month, two of the wheels failed, leaving the telescope unable to maintain its precise orientation.

All may not be lost, however. Jacob Aron, writing at New Scientist suggests that the Kepler switch to another planet finding method, known as ‘gravitational microlensing’. This method relies on the fact that the gravitational pull of an object will bend and magnify the light coming from more distant stars. On the plus side, this type of detection does not require the tight spacial positioning that the transit method demands. On the minus side, microlensing is best suited for finding planets outside the habitable zone of their stars rather than for detecting Earth-like planets, which was Kepler’s original mission.

Gravitational microlensing schematic

An illustration of the gravitational microlensing technique, showing an Einstein ring
Credit: Timberlake Studios.

This week’s episode of the excellent Big Picture Science podcast discusses the Kepler in detail.

Thursday, June 20, 2013

How hot is too hot?

What’s the hottest environment in which living organisms can thrive? It depends on the organism. There are Archae (single-celled prokaryotes that used to be classified as bacteria) that have been found thriving in 122oC. Remember, that’s much hotter than the boiling point of water, and presumably of the insides of the Archae. 

Multicellular organisms can’t take that amount of heat. One of the most thermophilic (heat-loving) metazoan organisms ever discovered is the Pompeii worm (Alvinella pompejana, shown above). These are a type of bristle worm that happens to live next to hydrothermal vents on the ocean floor. Although they are known to live at temperatures of 50oC (that’s 122oF for my fellow Americans), some reports suggest that they can tolerate far hotter temperatures, even up to 100oC. 

The best way to test these assertions would be to systematically vary the temperature within a controlled setting. Unfortunately, it has been impossible to bring living Pompeii worms up from the depths of the ocean into the laboratory. Until now.

French researchers, led by Juliette Ravaux of Université Pierre et Marie Curie, designed an apparatus to snatch up the worms at the foot of a black smoker and maintain them under extreme pressure all the way to the surface, where they are transferred into a specially designed aquarium. 

Once in the lab, the specimens were subjected to three thermal regimes. One group was maintained at a balmy 20oC. A second had their environment  gradually increased to 42oC for two hours.  For the final group, the temperature was raised to 55oC for two hours, upon which point the worms would have been allowed to recover at 20oC if they hadn’t already been dead.

There was no discernible damage to the worms who were subjected to 42oC water. Not so with the unfortunate creatures who spent time at 55oC. Interestingly, the group that stayed at 20oC the entire time had a lower survival rate than the 42oC group.

While the Pompeii worm can withstand high temperatures, the reports of its heat tolerance are clearly exaggerated. Good to know.

Ravaux, J., Hamel, G., Zbinden, M., Tasiemski, A., Boutet, I., Léger, N., Tanguy, A., Jollivet, D., & Shillito, B. (2013). Thermal Limit for Metazoan Life in Question: In Vivo Heat Tolerance of the Pompeii Worm PLoS ONE, 8 (5) DOI: 10.1371/journal.pone.0064074.

Wednesday, June 19, 2013

Just for fun: XKCD

If you spend any time on science blogs, chances are you've come across the work of xkcd. The xkcd empire includes exceptionally sharp critiques of math, science, and nerd culture.

There are cartoons (and don't forgot to hover over them for extra content).

Ten Thousand

Including what may be the best cartoon of all time:

Duty Calls

A 'What If' page where hypothetical physics questions are answered (did you know how many giraffes high a person can throw a ball?).

And a twitter feed that offers a host of interesting numbers and measurements:

Tuesday, June 18, 2013

Universal decolonization for the win against MRSA

MRSA (methicillin-resistant Staphylococcus aureus) is a huge problem in hospitals. That’s because once the usually benign bacteria establish an infection, they are nearly impossible to kill. They are resistant to almost all modern antibiotics. Ordinarily, our immune systems can handle the bugs (they aren’t more virulent than nonresistant Staph). Unfortunately, that isn’t always the case for hospital patients, who not only may be more immunologically vulnerable, but often offer easy access through open wounds or medical ports.

In an attempt to prevent MRSA from spreading in hospitals, health care workers have largely relied on two different methods. The first strategy was to screen specifically for MRSA, and then isolate and aggressively treat patients who test positive for the infection. The second is not to test for MRSA at all, but to follow universal decontamination procedures with every patient. 

In a large study published in the New England Journal of Medicine, these two techniques went head to head. Universal decolonization (removing all bacterial colonies) was the hand’s down winner, reducing all bloodstream infections, including those caused by MRSA, by 44%.

To achieve those results, patients had their nostrils swabbed twice a day with mupirocin antibiotic gel and were wiped down with chlorhexidine-impregnated antiseptic cloths. Hospital staff practiced standard contact precautions. 

One possible reason for the success of this method is the very fact that health care workers don’t have to wait for the results of tests before implementing treatment strategies. Everyone is wiped and swabbed, and as a result, the infection rate plummets.

I should point out that the doctors aren’t (yet) advocating that every person who enters a hospital submit to a full body strip and wipe down. All the procedures were done only on patients admitted to their hospital's intensive care units. I wouldn’t be totally shocked if that were to change, though.

More on this from Maryn McKenna at Wired Science.

Image: 2005 scanning electron micrograph (SEM) depicted numerous clumps of methicillin-resistant Staphylococcus aureus bacteria, commonly referred to by the acronym, MRSA; Magnified 9560x.

Huang, S., Septimus, E., Kleinman, K., Moody, J., Hickok, J., Avery, T., Lankiewicz, J., Gombosev, A., Terpstra, L., Hartford, F., Hayden, M., Jernigan, J., Weinstein, R., Fraser, V., Haffenreffer, K., Cui, E., Kaganov, R., Lolans, K., Perlin, J., & Platt, R. (2013). Targeted versus Universal Decolonization to Prevent ICU Infection New England Journal of Medicine DOI: 10.1056/NEJMoa1207290.

Monday, June 17, 2013

Solving race problems with a rubber hand

Lara Maister and Manos Tsakiris of the University of London, and Natalie Sebanz and Günther Knoblich of Central European University have a novel approach to combatting racism. They give people the rubber hand illusion treatment.

One of the reasons that racism is so difficult to eradicate is that many people genuinely feel less empathy for members of other races. The insidious thing is that they may not even be aware that they feel this way. 

If they don't know they have these feelings, then how do we know they do? One way is by using Implicit Association Tests (IAT). These tests ask people to sort words or images into groups as quickly as they can. For example, a volunteer might have to decide whether to put a lemon in the ‘good’ or ‘bad’ category. People are much quicker at sorting things in a way that makes sense to them. A racist might put a dark-skinned face in the ‘good’ column for the benefit of observers, but he’ll be a lot slower about it than a person who really believes dark-skinned people are good. 

Sure enough, even people who don't consider themselves bigoted and who make every effort to act and speak in unbiased ways often display inherent prejudices when subjected to these kinds of tests.

This sounds like really bad news for combatting racial prejudice and misunderstanding. However, Lara Maister and her colleagues have some good news for us. It turns out you can make people more sensitive to the plight of outgroups, and all it takes is a rubber hand. Or more specifically, the rubber hand illusion.

First, what is the rubber hand illusion? Watch this clip to find out.

The interesting twist is that the researchers gave light-skinned Caucasians dark-skinned rubber hands.

Before the experiment, the light-skinned participants were given IATs to measure their unconscious attitudes toward dark-skinned people. Once this baseline level of racism was established, the participants were treated to the rubber hand illusion with a dark-skinned rubber hand. Immediately afterward, they were asked to rate how much the rubber hand had seemed like a part of their own bodies. Finally, the volunteers repeated the IAT.

People who felt the illusion of ownership of the dark rubber hand more strongly also became implicitly more positive toward dark-skinned people. Apparently, people subconsciously think, ‘hey, if I’m part black myself, they can’t be that bad.’

This doesn’t surprise me. Anything that makes the ‘other’ more familiar is going to reduce fear and animosity. I’m not sure whether this information will prove to be that useful though. For one thing, we can’t require that citizens undergo rubber hand treatment, and even if we did there’s no guarantee that the effects would last. Still, it’s good to know that racial attitudes aren’t as deeply ingrained as we might think.

Maister, L., Sebanz, N., Knoblich, G., & Tsakiris, M. (2013). Experiencing ownership over a dark-skinned body reduces implicit racial bias Cognition, 128 (2), 170-178 DOI: 10.1016/j.cognition.2013.04.002.

Friday, June 14, 2013

Just for fun: Extra!

I published my Friday post yesterday, so you guys get an extra 'Just for fun' this week. It's usually only the Facebook fans who get extra videos! 

Here's a classic by Minute Physics.  Enjoy. 

Thursday, June 13, 2013

Human genes can't be patented? Not so fast

Normally, I only post one story a day, but I just couldn’t wait until tomorrow for this!

Today, the Supreme Court ruled that human genes cannot be patented! Yeah! Except, they didn’t really rule that way, because the decision included this paragraph:
...but the lab technician unquestionably creates something new when cDNA is made. cDNA retains the naturally occurring exons of DNA, but it is distinct from the DNA from which it was derived. As a result, cDNA is not a “product of nature” and is patent eligible under §101, except insofar as very short series of DNA may have no intervening introns to remove when creating cDNA. In that situation, a short strand of cDNA may be indistinguishable from natural DNA.
Let me translate. 

A gene, as it exists as part of of your chromosome, contains both coding parts, which are called ‘exons’, and non-coding parts, which are called ‘introns’.  After being transcribed into RNA, the non-coding bits are removed to make mature mRNA. You can see that in the diagram below. 

The mRNA is then translated into a protein. Although this doesn’t ordinarily happen in mammalian cells, a geneticist can take that mRNA and reverse transcribe it back into DNA. This is called ‘complementary DNA’, or cDNA, and it's identical to the original gene, except without the introns. 

Thus, the court ruling says that if I chop a piece of DNA out of your chromosome, I can’t patent it. But if I make cDNA from your gene (and remember, the cDNA has all the coding parts from which I can make the original protein), then I can patent that*.  

And that’s different from patenting human genes how?

*It's been pointed out to me by David Pacheco that the Supreme Court did not specifically rule on whether cDNA is patentable, it just didn't say cDNA definitely could not be patented, as it did with naturally occurring DNA. In other words, the Court's decision may be more nuanced than I've given them credit for. Nonetheless, the ruling is far from a ban on patenting human genes as many of the headlines would have you believe.

New and improved surgical biopsies

When doctors are trying to figure out what’s wrong with you, they’ll often want to take a biopsy of the affected area. This usually means inserting a pair of biopsy forceps and pinching off a piece of your flesh. You can see an example of such a device below, courtesy of Device Technologies. 

If it makes you squeamish, note that the jaws of such tools are only a couple of millimeters long. That’s not tiny enough for the researchers at Johns Hopkins, however, who have manufactured and tested autonomous microgrippers that are ten times smaller.

This image depicts an mu-gripper near the opening of an endoscopic catheter. 
Credit: Evin Gultepe, Gracias Lab, Johns Hopkins University.

The minute star-shaped objects are composed of temperature-sensitive metals that squeeze closed when they are exposed to body temperature. Doctors can use a catheter to deploy hundreds, or even thousands, of them into a suspicious region of the body. In a few minutes, the microgrippers warm up and close around tissue samples. Because the grippers contain nickel, they can then be collected with a magnetic probe.

This is much less invasive than conventional tissue sampling for a number of reasons. First, you’re collecting much smaller samples. Second, you can deploy as many microgrippers as you need to be reasonably sure you’re getting a representative tissue sample. To get the same result, doctors might have to make tens of sequential forceps biopsies. Finally, you need far less precision and training to get the samples you want, which might make it faster and easier to perform biopsies.

So far, animal tests have been promising, though more refinements will be necessary before the doctors move on to human trials. At a minimum, I'm sure patients will want to know whether doctors can reliably retrieve every last microgripper and what the dangers are of leaving one behind.

Here's an animation explaining their usage:

Or watch one in action here:

Gultepe, E., Yamanaka, S., Laflin, K., Kadam, S., Shim, Y., Olaru, A., Limketkai, B., Khashab, M., Kalloo, A., Gracias, D., & Selaru, F. (2013). Biologic Tissue Sampling With Untethered Microgrippers Gastroenterology, 144 (4), 691-693 DOI: 10.1053/j.gastro.2013.01.066.

Wednesday, June 12, 2013

Just for fun: The invisible artist

Many artists claim to lose themselves in their work, but no one does it quite like Liu Bolin. Judge for yourself:

Hiding in New York No. 7 — Made in China, 2012. Photo: courtesy of Eli Klein Fine Art, © Liu Bolin

You can see more of Bolin's work here (don't miss the dragon), or watch his TED talk where he explains his origins in protest and demonstrates his technique:

Tuesday, June 11, 2013

Tunneling for tumbling ants

Why are ant tunnels so uniform in diameter? If you guessed for ease of movement, you'd be only partially right. Ants do need their tunnels to be accessible passageways, but there's a more important reason for building them to such exacting specifications. It seems that ants construct their tunnels of the optimal size to catch them when they fall down the shafts, something that happens a lot more often than you might suspect. Ants are surprisingly clumsy travelers.

Say what you will about fire ants (Solenopsis invicta), they’re experts at building complex underground pathways. They’re also readily available around the Georgia Institute of Technology, which is where Daniel Goldman and his team work. 

The researchers collected the ants and provided them with soils containing a variety of particle sizes and moisture contents. Regardless of the substrate, the ants constructed tunnels with the same diameter. The tunnels varied in length and direction, but were always slightly wider across than one ant length. You might think this width was selected for as the smallest size that still permits rapid movement. However that wasn't the case. 

In a rather surprising discovery, the scientists found that ants use their antennae to catch themselves as they tumble down vertical tunnels. This suggests that tunnel diameters may be optimized not so much for rapid deployment as for letting ants recover from slips. 

If you want to see examples of an ant slipping down a tunnel, check out this video of Goldman explaining their work.

By the way, as interesting as these studies are, and who doesn’t find ants fascinating, Goldman and his colleagues have another purpose. They hope to someday be able to apply what they learn to the field of robotics. After all, ants are experts at building uniform structures out of diverse materials. As he explains:
Lots of the materials in disaster sites - landslides, rubble piles - are loose materials, which you're going to potentially have to create structures out of.
If all goes well, in future disaster zones we could have multitudes of mechanical ants or little robots that look like  cockroaches that will swarm all over the place.

Gravish, N., Monaenkova, D., Goodisman, M., & Goldman, D. (2013). Climbing, falling, and jamming during ant locomotion in confined environments Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1302428110.