Science-- there's something for everyone

Thursday, April 24, 2014

Jet lag? There's an app for that

If you’ve flown large distances, chances are you’ve experienced jet lag. This condition occurs when a person’s internal clock does not align with the environment. Until the traveler readjusts his circadian rhythm, he may not be hungry when it’s time to eat or sleepy when it’s time to sleep. But it’s not just travelers who are affected by jet lag. Shift workers too must adjust to being productive at times when their bodies think it’s time to sleep.

Needless to say, it can be quite disruptive to live this way for long. For most people, readjusting, or ‘entrainment’ takes about one day per hour shifted. The recovery process can be sped up by exposure to bright light, but only if that exposure occurs at the right times. So, how does one know what those times are? Wouldn’t it be great if there were an app for that?

Enter Kirill Serkh of Yale University and Daniel Forger from the University of Michigan. They created a mathematical model for optimally scheduling anti-jet lag light periods. Then Olivia Walch made it an app:



To follow the apps recommendations, a person should experience one block of light and one block of darkness per day (and they should be very bright and very dim respectively) starting and ending at specified hours. For example, the app might tell the person to turn on the lights at 5:00 am and turn them off 7:20 pm. If you follow the recommendations, you should be able to knock a couple of days off your recovery time.



Serkh, K., & Forger, D. (2014). Optimal Schedules of Light Exposure for Rapidly Correcting Circadian Misalignment PLoS Computational Biology, 10 (4) DOI: 10.1371/journal.pcbi.1003523.



Wednesday, April 23, 2014

Just for fun: Herding reindeer

When does herding reindeer become an art project? When you can film it from your hexacopter camera drone. 

IMG_6207
Jan Helmer Olsen with his camera equipment

Below, Sami people in Northern Norway manage their herds.






Tuesday, April 22, 2014

The secret life of cells


In collaboration with the BioVisions program at Harvard, Xvivo Scientific Animation has created some amazing animations of the insides of cells. The first one was made in 2006 and entitled The Inner Life of the Cell.



You can watch DNA and RNA zipping and unzipping and proteins busily going about their business in their internal metropolis.

Now there's a new video (Inner Life of a Cell/ Protein Packing) which gives people a better idea of just how crowded it is within a cell: 



In both videos, the oddly shaped clumpy objects are proteins. Here's one shot from the second animation, showing a variety of proteins in close contact, just as they are in real life:


A jumble of proteins inside the cell, visualized in a scientific animation. Credit Harvard University, XVIVO Scientific Animation

Carl Zimmer has more about these videos.


Monday, April 21, 2014

Does hunger make you want to stick pins in people?

Do you get irritable when you’re hungry? Do you tend to take out that aggression on your loved ones? If so, you’re in good company. Brad Bushman of The Ohio State University and his colleagues found that when people have low glucose levels, they like to stick pins in dolls representing their spouses.

The researchers measured the glucose levels of 107 couples twice a day (before breakfast and late evening) for three weeks. Every evening, participants were given voodoo dolls and told to stick 0 to 51 pins into them to demonstrate how much anger they felt towards their spouses. The pin-sticking was done alone without the spouse being present.

At the end of the 21 days, each person participated in a button-pressing game. Whoever pressed the button first was given the privilege of blasting the loser with some really unpleasant sounds (think dentist drills and chalkboard squeaks). The winner could pick both the decibel level and the duration of the sound blast, including no blast at all.

The participants thought they were competing with their spouses, who were not visible during the test. In reality, they were competing with a computer that made sure they lost 13 out of 25 trials and that they received a random sampling of the noise options.

The researchers found that when they accounted (as best they could) for marital and sexual satisfaction and for typical levels of aggression (some couples were routinely more aggressive toward each other than others), daily evening glucose levels did correlate with number of pins stuck in the voodoo dolls. In case you’re wondering, women tended to stick more pins than men.

In the noise-blast test, people with lower average evening glucose levels blasted what they thought were their spouses with louder and longer noise bursts.

There are a lot of possible things besides just low glucose levels that can make a person want to stick pins in his spouse or blast her with unpleasant noises. However, between other trials showing that people have less impulse control when they have low glucose levels and my own personal experiments with hunger and irritability, I find these results totally believable.
 


Bushman, B., DeWall, C., Pond, R., & Hanus, M. (2014). Low glucose relates to greater aggression in married couples Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1400619111.



Thursday, April 17, 2014

Why do Zebras have stripes?

Why do zebras have those flashy stripes? In a world where predators could be lurking anywhere, being so boldly conspicuous seems like a huge handicap. There must be some kind of evolutionary advantage to that distinctive coloring and biologists have come up with several ideas. The stripes might be courtship or other social cues, helping the animals mate or bond in groups. They might allow the animals to identify each other. They might confuse predators by making the zebras blend together. Perhaps they offer some type of temperature control. Nope. Tim Caro of the University of California, Davis and his colleagues ruled out those possibilities. It turns out that it’s all about the bugs.

That’s right, bugs. More specifically, biting insects like tsetse flies, stomoxys stable flies and tabanid biting flies. The researchers found that the ranges of animals with body stripes (zebras) exactly matched the ranges of these bloodsucking insects.

In the diagram below, you can see the different species of wild equine. Some have full body stripes, some leg stripes, some neck stripes and some are not striped at all. The blue dots show species not plagued by tabanid flies. Notice that those are the animals with no stripes. There was no such correlation with other factors like the presence of certain predators or temperature.




Striping and tabanid activity.
Phylogenetic tree of equid subspecies showing leg stripe intensity (inside circles) and proportion of geographic range overlap with 7 consecutive months of temperature lying between 15 and 30 C and humidity between 30 and 85% (outside circles).
Drawings by Rickesh Patel.
DOI: 10.1038/ncomms4535,

But aren't there plenty of other animals living in those same areas that are not striped? Yes, but zebras are covered with short hairs that biting insects can penetrate with their mouth parts. Non-striped mammals living in the same areas typically have longer, thicker fur that the flies can't get through.

How do stripes help animals avoid biting insects? Apparently, many insects, including tabanids and tsetses, don’t like to land on striped surfaces. And indeed, solid colored feral horses suffer much more harassment from flies than do their striped cousins.

The idea that insect parasites drove the evolution of stripes isn’t settled science yet, but it’s a fascinating hypothesis. I can’t wait to see if further studies confirm it.



Caro, T., Izzo, A., Reiner, R., Walker, H., & Stankowich, T. (2014). The function of zebra stripes Nature Communications, 5 DOI: 10.1038/ncomms4535,




Wednesday, April 16, 2014

Just for fun: X-ray art

Photographer Hugh Turvey uses x-rays to create works of art that he calls Xograms. Here's one example, an image he calls "Femme Fatale".

Picture of womans foot x-ray high heels 
You can read an interview with Turvey and see more of his work here.



Tuesday, April 15, 2014

First asteroid with rings

Artist’s impression of the rings around Chariklo
Artist's rendition of Chariklo, Courtesy of ESO
The Kuiper asteroid belt is full of objects that orbit the sun out beyond Neptune. Some of these objects have orbits that cross the paths of the gas giants, but they don’t generally get any closer than that.

This means that most of these objects are too far away for us to ever learn much about them if we can even detect them in the first place. But sometimes we get lucky. If one of these objects passes in front of (and consequently dims the light) of another star, we can use that information to determine how big the object is.

When astronomers observed an asteroid named Chariklo passing in front of a star (not the sun) last summer, they were able to calculate not only its size (250 kilometers in diameter), but something far more amazing. They found that Chariklo has rings. To be exact, it has two rings, one thin one and one thicker one. This makes the asteroid only the fifth object in our solar system to have rings, after Jupiter, Saturn, Uranus and Neptune.

How did the cosmologists come this conclusion? As Chariklo traveled across the path of that distant star, the light from that star was dimmed. But that slight fading didn’t happen just once, as it would if a single body were crossing in front of the star. Instead, there were five light dips: a small one (A), a bigger one (B), a much bigger one (C), then one exactly the same size as B, and finally one the exact same size as A. The regularity of the dips strongly suggests that A and B are rings.

It’s very likely that Chariklo is not the only asteroid with rings. After all, we once thought Saturn was the only planet with rings, and we now know that all the gas giants have them. It may be all the more amazing if relatively tiny asteroids can have rings since none of the rocky planets, which are far larger than asteroids, have rings. Even Mercury is nearly 20 times larger than Chariklo and it doesn't have rings.

You can read more about this at Bad Astronomy.




Camargo, J., Vieira-Martins, R., Assafin, M., Braga-Ribas, F., Sicardy, B., Desmars, J., Andrei, A., Benedetti-Rossi, G., & Dias-Oliveira, A. (2013). Candidate stellar occultations by Centaurs and trans-Neptunian objects up to 2014 Astronomy & Astrophysics, 561 DOI: 10.1051/0004-6361/201322579.