Science-- there's something for everyone

Tuesday, May 20, 2014

What's in that sea water you just swallowed?

Photographer David Littschwager has captured this incredible image of a drop of seawater magnified 25 times.

You can read descriptions of what all these critter are at Dive Shield.

Monday, May 19, 2014

The world's most dangerous animals

What do you think is the most dangerous animal on Earth? To be more specific, which animal kills the most humans? Here's an infographic that might surprise you:

The World's Deadliest Animals Infographic, Mosquito Week | The Blog of Bill Gates

As you can see, number one and two, mosquitoes and other humans, completely dwarf any

other creatures. 

Bill Gates (yes, that Bill Gates) put this graphic on his blog to kick off 'Mosquito Week' and bring attention to the problem of mosquito-born illnesses.

Friday, May 16, 2014

The pocket guide to bullshit prevention

Michelle Nijhuis has done us all the service of providing The Pocket Guide to Bullshit Prevention:

Screen Shot 2014-04-23 at 8.46.43 AM

Nijhuis gives an example of how she uses this Bullshit Prevention Protocol (BPP) over at The Last Word On Nothing. It turns out although Beijing is very smoggy, the Chinese are not in fact televising sunrises so that their citizens will remember what the sun looks like.

Thursday, May 15, 2014

Why can't we save stranded dolphins?

It’s tragic when whales and dolphins strand themselves on beaches. It becomes even more sad when, despite heroic efforts by teams of veterinarians and volunteers, the animals still don’t survive. Why do some dolphins swim away and others restrand themselves and die?

To find out, scientists led by Sarah Sharp of the International Fund for Animal Welfare (IFAW) and Tufts Cummings School of Veterinary Medicine and her colleagues analyzed data from stranded common dolphins. Common dolphin strandings are unfortunately common at Cape Cod, Massachusetts where the research was conducted. During a 2 year period, the researchers responded to 143 stranded common dolphins where the animal was still alive.

Upon arriving on the scene, IFAW vets took measurements and blood samples and performed physical examinations while quickly preparing the animal for transport to a suitable release site. All dolphins were released the same day they were found. A subset of these were tagged for satellite tracking. Dolphins that were still swimming around after three weeks were considered ‘survived’. Dolphins that died during the initial response effort (but after blood drawing) or that restranded themselves or were found dead within that 3 week period were considered ‘failed’.

The researchers found blood chemistry differences between the survived and failed groups. Anemia was a very strong indicator that the animal would not survive. Failed dolphins also tended to have cardiovascular abnormalities, pneumonia or liver disease. There were also differences in length to girth ratio in surviving versus failing dolphins.

All of this suggests that by the time a dolphin strands himself on a beach, he's probably beyond saving. In many cases, nothing can be done for him. There are animals that do survive, however, and identifying them is critical, especially during mass strandings, when responders must quickly decide which animals to save first and which to euthanize. The data collected by Sharp and her colleagues could become valuable triage tools for managing marine mammals.

Sharp, S., Knoll, J., Moore, M., Moore, K., Harry, C., Hoppe, J., Niemeyer, M., Robinson, I., Rose, K., Brian Sharp, W., & Rotstein, D. (2013). Hematological, biochemical, and morphological parameters as prognostic indicators for stranded common dolphins ( from Cape Cod, Massachusetts, U.S.A. Marine Mammal Science DOI: 10.1111/mms.12093.

Wednesday, May 14, 2014

Folding wasp wings

Pennsylvania State University researcher István Mikó and his colleagues have described a couple of new wasp species.

Here's one of them: Afrevania longipetiolata. Notice anything unusual?

Brightfield images of Afrevania longipetiolata, anterior to the left.A: Dorsolateral view. B: Dorsal view.

It has teeny tiny wings. Or at least that's how they first appear. In reality, the wings are folded in a way that's completely new for wasps. You can see the complex folding pattern below:

Fore wing of Afrevania longipetiolata sp. nov.A: CLSM micrograph of the fully unfolded fore wing, anterior to the left.
B: Brightfield image of the fully unfolded fore wing, anterior to the left.
C: Brightfield image of the folded fore wing, anterior to the top.

Interestingly, while other wasps don't fold their wings this way, some cockroaches, and these wasps prey on cockroach eggs. Is this the best way for an insect to get into the places where cockroaches lay their eggs? 

Mikó, I., Copeland, R., Balhoff, J., Yoder, M., & Deans, A. (2014). Folding Wings like a Cockroach: A Review of Transverse Wing Folding Ensign Wasps (Hymenoptera: Evaniidae: Afrevania and Trissevania) PLoS ONE, 9 (5) DOI: 10.1371/journal.pone.0094056.


Tuesday, May 13, 2014

Wonderful spinning

This may be the most wonderful hoop trick I've ever seen:

But it's actually part of a wonderful spinning series.

Monday, May 12, 2014

How to enjoy a sting in the face

This is a grasshopper mouse.

This is a bark scorpion.

Grasshopper mice eat bark scorpions. They often get stung in the process. Luckily for the mice, the scorpion venom acts like an analgesic for them. Yes, that’s right, the mice feel better after a few stings in the face.

Researchers from Michigan State University led by Ashlee Rowe tested the painkilling effects of scorpion venom by injecting mouse foot pads with either the venom or a simple saline solution. Mice react to foot pain by licking their feet and sure enough the unfortunate mice in the experiment did spend time licking their feet. But the scorpion-injected mice licked a lot less than the saline-injected mice.

How is this possible? The sensation of pain is created when sodium ions pass through special channels in cell membranes. Most mammals have one type of sodium channel, but the grasshopper mice have a particular genetic variation. Scorpion venom can bind to the amino acids in the mouse channels, effectively blocking them.

Needless to say, this result has interesting implications for medicine, and not just for people who get stung in the face by scorpions. If researchers can find compounds that block our sodium channels, that could be a powerful painkiller.

Friday, May 9, 2014

Focusing without glasses

Now, here's a trick I can use. Next time I forget my reading glasses in a restaurant, I'll just peer at the menu through my fingers. This really does work and here's why:

Thursday, May 8, 2014

Introducing SensaBubble

University of Bristol Professor Sriram Subramanian and his colleagues have invented the SensaBubble. It's a way to make bubbles that contain different scents and upon which different images can be displayed.

This isn't meant to be a updated version of a lava lamp. The researchers envision using the bubbles to send information to people via scent and color. In other words, it's a human-computer interface. 

I have to say, the researchers who developed SensaBubble seem a lot more optimistic about its use as a communication device than I am. If you had to send someone a bubble smelling like a bacon cheeseburger to tell them dinner's ready, you might as well just yell.

Wednesday, May 7, 2014

Explaining the hemihelix

If you’ve ever had a child or been a child, I guarantee you are familiar with the hemihelix. It’s the shape your slinky takes on when the coils suddenly switch to the opposite direction and you can’t make the thing squeeze neatly together any more. That kink in the middle changes the slinky from a helix to a hemihelix.

You can find hemihelices with just the one direction change, or ‘perversion’ in nature. Roots will sometimes spiral in one direction and then switch to going around the other way as they penetrate the soil. If you want a spring with multiple perversions, you’ll have to create it in the lab, and that’s exactly what Harvard University scientists, led by Jia Liu, did.

The researchers played with elastomer strips to figure out what properties (width and length) and what energies were required to make the rubbery strips switch from helix, to single-perversion helix, to multiple perversion helix. If your strips have the right cross-section, you can get cool shapes like the ones below.

Top: regular helix
Middle: a hemihelix with one perversion marked by an arrow
Bottom: a hemihelix with multiple perversions
The scale bar is 5 cm for each image.
Credit: Jiangshui Huang

Did I say play? This is serious science folks. 

Liu, J., Huang, J., Su, T., Bertoldi, K., & Clarke, D. (2014). Structural Transition from Helices to Hemihelices PLoS ONE, 9 (4) DOI: 10.1371/journal.pone.0093183.

Tuesday, May 6, 2014

Robonaut gets some new legs

Ever hear of Robonaut? Even if you haven't, you've probably guessed that it's a robotic astronaut. In other words, it's a robot that's designed to help out on space missions. Robonaut just received a new pair of legs. Apparently, it will be even more helpful now that it can grip things with its toes.

This is a bigger change than you might think. Since it's arrival on the International Space Station (ISS) three years ago, Robonaut has had to make due with only an upper body. Once its legs have been properly attached, it will be able to move about the ISS.
Robonaut attached to Centaur 1 cart

Among Robonaut's tasks are to assist with medical procedures. Now it will be able to to go to its patients.

Monday, May 5, 2014

The HI-SEAS Mission to Mars--no, that's not a pirate movie

There’s a new mission to Mars underway, only it’s not actually going anywhere. The second Hawaii Space Exploration Analog and Simulation, or HI-SEAS mission (who doesn’t love cosmologists?) takes place atop Mauna Loa in Hawaii.

Three men and three women, out of a pool of 700 applicants, will share a 1000 food habitat for four months. They’ll be simulating life on Mars, which means a 20 minute delay in all communications and only one shower per week. Also, no leaving the habitat without your spacesuit.

 Yajaira and the hab Photo by Sian 

Friday, May 2, 2014

Wellcome Image Awards 2014

If you like beautiful, fascinating photographs, you're going to love the Wellcome Image Awards.

Here's the overall winner, a dual-energy computed tomography scan of a patient with an artificial heart:


I was also pretty riveted by this image: a head louse egg (nit) attached to a human hair. No wonder they're so hard to get rid of!


You can see all of the pictures at this slideshow.

Thursday, May 1, 2014

What is that you're eating?

I love this artist! Painter Hikaru Cho teaches us that all is not as it seems.

Take this lovely cucumber.

Artist Paints Common Foods to Disguise them as Other Foods vegetables painting optical illusion fruit food
©cho All Right Reserved.

Maybe a closer look is in order:

Artist Paints Common Foods to Disguise them as Other Foods vegetables painting optical illusion fruit food
©cho All Right Reserved.

You can see more food surprises here, but that's not all Cho does. She also adds body parts and zippers where they don't ordinarily belong:

肌衣 背中チャック(画材:アクリル絵の具)
©cho All Right Reserved.

Wednesday, April 30, 2014

Cell races

HL-60 cells are human promyelocytic leukemia cells that were originally obtained from a woman with leukemia. They are valuable biomedical tools that are used in many studies. But really, doesn't everyone want to know how fast they can go? In particular, could they beat Dictyostelium (amoebic slime mold) cells in a race?

Inquiring minds want to know. At least, the inquiring minds behind the first World Dicty Race want to know. They're encouraging labs to submit to submit their fastest cells for a show down.

You can learn more about it here.

Tuesday, April 29, 2014

Don’t pee in the pool


The most common method for keeping swimming pools free of microbial pathogens is to add chlorine. Unfortunately, the chlorine in the water can combine with other molecules to form harmful byproducts like trichloramine (NCl3) and cyanogen chloride (CNCl). Researchers from China Agricultural University and from Purdue University found that this is particularly apt to happen when the chlorine is combined with uric acid.

Now, before you jump to conclusions, I should say that uric acid is present in human sweat. In really tiny amounts. There’s nearly 400 times more uric acid in urine than in sweat. So, I guess go ahead and jump to that conclusion because according to the authors, about 93% of the uric acid in swimming pools comes from pee.

How bad could it be? We
ll, NCl3 has been associated with severe lung injury. CNCl can affect the heart, lungs and central nervous system.

Bottom line: don’t pee in the pool. Even if you’re an olympic swimmer.

Lian L, E Y, Li J, & Blatchley ER 3rd (2014). Volatile disinfection byproducts resulting from chlorination of uric Acid: implications for swimming pools. Environmental science & technology, 48 (6), 3210-7 PMID: 24568660.

Monday, April 28, 2014

How did humans spread around the world?

We know that all human beings (Homo sapiens sapiens) can trace their origins back to Africa. Sometime between 100 and 200 thousand years ago (ka) the first of these modern humans migrated out of Africa and spread across the rest of the globe.
One line of evidence for this is that the further you go from sub-Saharan Africa, the more similar people are genetically.

Think about this way: let’s say there are ten different people living in Africa. One of them leaves. Over the next 100 ka, his descendants settle throughout Asia, but they all still share the common ancestor that left Africa. The descendants of the nine people who remained in Africa have no such commonality. Their shared ancestor dates from the evolution of the human species far earlier. Therefore, the people living in Africa today are far more diverse genetically than any of the groups living elsewhere in the world.

So far so good. What isn’t clear is whether the dispersal from Africa occurred as a single event or multiple events at different times in history. And what route did those groups of people use as they traveled around the world? Hugo Reyes-Centeno of Eberhard Karls University of Tübingen and his colleagues used both genetics and cranial features to compare four possibilities: a single dispersal with a northern route, a single dispersal with a southern route, multiple dispersals using both routes, and multiple dispersals using both routes, but where groups of people became stranded and thus genetically isolated along the way.

They conclude that the most likely scenario is the last one. Around 130 ka, humans began traveling across Southern Asia. A separate diaspora occurred about 50 ka taking humans into Europe.

Reyes-Centeno, H., Ghirotto, S., Detroit, F., Grimaud-Herve, D., Barbujani, G., & Harvati, K. (2014). Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1323666111.

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. 

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.

Monday, April 14, 2014

Get ready for a lunar eclipse

If you live in North America, you're going to have a chance to see a lunar eclipse tonight.

A lunar eclipse occurs when the moon passes through Earth's shadow. Phil Plait has an excellent description of this upcoming event over at Bad Astronomy, including this helpful diagram:

geometry of an eclipse
Note: objects are not to scale. Drawing by Shutterstock / fluidworkshop 

You can also see an explanation of how the eclipse will effect the Lunar Reconnaissance Orbiter (LRO), which is currently orbiting the moon, below:

When is the best viewing? The main event should take place between about 2- 5 am EDT. Plan accordingly.

Friday, April 11, 2014

What makes a Stradivarius violin so special?

PHOTO: In this March, 27, 2014 photo, three violinists play Stradivarius violins during a rehearsal at the Colburn School in Los Angeles.

The superiority of Old Italian violins like those made by Stradivari is legendary. For hundreds of years, people have tried to discover the source of that excellence. Was it the varnish? A property of the wood? The surprising answer may be that it's a trick question. Those old violins may not actually be any better than new violins. So say renowned violin soloists during blinded tests.

Claudia Fritz of Sorbonne Universités and her colleagues invited ten multiple award winning violin soloists to participate in their study. All of the musicians had experience playing Old Italian violins and some used them exclusively. While wearing welder’s goggles that made it impossible to identify violins by sight, the violinists were presented with six new violins (no more than two decades old, but antiqued to have the same worn edges as much older violins) and six old violins (made by 17th and 18th century masters like Guarneri del Gesu and Stradivari).

After playing their own violin as a reference, the subjects tried out the twelve violins and ranked them for preference, as if they were considering buying them. Once he had selected his four highest rated violins, each musician was presented with three violins: his own, his top pick out of the twelve, and his top pick from the opposite category. For example, if he liked an old violin the most, the third violin would be his top ranked new violin. Those three violins were then rated for a variety of musical attributes such as tone quality and projection.

The entire experiment was repeated twice, first in the practice room within the home of professional musicians and later in a 300 seat concert hall.

The two highest scoring violins were both new ones. Four of the six violins that had been ranked number one by at least one musician were new ones. All but one new violin was at least one person’s top pick, whereas four of the six old violins were no one’s top choice. For most criteria, the violinists preferred a top ranked new violin to their own violin. In contrast, they tended to prefer the qualities of their own violins to those of old violins.

No one is suggesting that the old Italian violin makers did not create masterpieces. It’s just that those instruments may not be as magical as they are given credit for. It also means that our modern violin manufacturers are doing an excellent job.

Fritz, C., Curtin, J., Poitevineau, J., Borsarello, H., Wollman, I., Tao, F., & Ghasarossian, T. (2014). Soloist evaluations of six Old Italian and six new violins Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1323367111.

Thursday, April 10, 2014

Sunset paintings are more than just art

If you wanted to study meteorological conditions before the advent of modern recording devices, what would you do? Well, if you’re like Christos Zerefos of the Academy of Athens or his colleagues, you’d look at old paintings. The researchers used paintings of sunsets made from the year 1500 to 2000 to estimate the amount of pollution in the air at those times.

First off, you may be wondering what could have produced enough pollution to blot the sky hundreds of years before the industrial revolution. The answer is volcanic eruption. Sure enough, paintings made within a few years of major eruptions have redder skies than paintings made at other times. This is because the ash and dust in the air after an eruption scatter the sunlight, shifting the ratio of red to green light.

To test how accurately a painting could be in predicting the clarity of the atmosphere, the researchers asked Panayiotis Tetsis, a colorist and landscape artist, to paint a series of sunset pictures from the island of Hydra. Unbeknownst to Tetsis, during the experiment there happened to be a Saharan dust storm blowing over Greece. You can see the results below:
Tetsis paintings
Greek landscape painter Panayiotis Tetsis created the top images on June 19 and 20, 2010, respectively. The photographs below them reflect the real sunsets on those evenings. There were more aerosols in the sky, and more red in Tetsis' painting, on June 19.
P. Tetsis (paintings) and C. Zerefos (photos).

The top two panels are of Tetsis’ paintings, the bottom panels are photographs taken while he was painting. The panels on the left were made during the dust storm, the panels on the right were made the next day. Notice how much redder the sky is during the dust storm in both the photographs and the paintings.

If earlier artists were equally good at capturing color differences, then paintings made hundreds of years ago could be useful for determining pollution levels.

Zerefos, C., Tetsis, P., Kazantzidis, A., Amiridis, V., Zerefos, S., Luterbacher, J., Eleftheratos, K., Gerasopoulos, E., Kazadzis, S., & Papayannis, A. (2013). Further evidence of important environmental information content in red-to-green ratios as depicted in paintings by great masters Atmospheric Chemistry and Physics Discussions, 13 (12), 33145-33176 DOI: 10.5194/acpd-13-33145-2013.

Wednesday, April 9, 2014

Just for fun: Cyborg drummer

Drummer Jason Barnes lost his right arm after being electrocuted two years ago. Thanks to help from Gil Weinberg’s lab at Georgia Tech, Barnes now has a robotic arm with which to make music.

Notice that the prosthesis holds two drumsticks, only one of which is controlled by Barnes’ bicep muscles. The second drumstick is an independent robotic device that can improvise, based on what Barnes is doing with the drumsticks he controls.

Tuesday, April 8, 2014

Can you outrun speed cameras?

File:New Zealand PW Speed Camera Area.svg

A group of physics students from the University of Leicester calculated whether someone could defy speed cameras by outrunning them. The good news is that it is definitely possible. The bad news is that he’d have to be traveling at 119 million miles per hour.

The students based their calculations on what it would take to create a sufficient Doppler effect to blur the images taken by a camera. The Doppler effect is the change in frequency of waves as the object emitting those waves first approaches and then passes the observer. You can notice this yourself in the changing sound of a siren as an emergency vehicle catches up with you and then passes you. The sound waves between you and the vehicle ‘bunch up’ as the distance closes, resulting in a higher pitched siren. As the vehicle moves away from you, the sound waves stretch out.

In light, objects moving away from an observer are shifted toward the red end of the spectrum. The faster the object, the bigger the shift. Because speed cameras take pictures of fleeing cars, the students worked out how fast a car would need to travel to create a redshift great enough to make the license plate undetectable. The answer: about a sixth of the speed of light.

I feel a couple of caveats are in order. If you’re a fan of the show Mythbusters, then you know that Jamie Hyneman and Adam Savage also tried to outrun speed cameras and were able to do so by going about 200 miles per hour. This is obviously considerably less than a hundred million miles per hour. One possible reason for the discrepancy is that the University of Leicester students ignored camera speed. If a camera has a shutter speed of 1/1000 of a second, a car traveling 200 miles per hour would have moved about three feet during the time it took the camera to snap the image. I’m not sure what the shutter speed or focal range is for traffic cameras, but it’s not hard to see how the world’s fastest cars could defeat them.

One more thing to note: this study was conducted in the United Kingdom, where license plates are typically yellow. The exact speed required to create enough of a doppler shift to fool the cameras will vary slightly with different plates.

D. Worthy, R. Garner, J. Gregory, & J. Taylor-Ashley (2013). P3 10 Red-shifted Speed Cameras Journal of Physics Special Topics, 1229 (11).

Monday, April 7, 2014

Can you tell real from faked pain?

Take a look at the pictures below. One of them is an expression of real pain and the other is faked. Which one do you think is real? 
Credit: Image courtesy of University of California - San Diego

I’ll reveal the answer a little later. But for now, would it surprise you to know that most people are no better than chance at distinguishing actual pain from simulated pain? Even after training, human observers were only 55% accurate in picking out who was only faking. Computers, on the other hand, have no such limitations and could distinguish genuine from faked expressions 85% of the time.

Scientists led by Marian Bartlett of the University of California, San Diego and Kang Lee of the University of Toronto compared human observers with a computer vision system called CERT (Computer Expression Recognition Toolbox). CERT detects human faces and codes the positions and actions of facial muscles using a program called FACS (Facial Action Coding System). FACS scores incremental movements in individual facial muscles.

The models for the experiment were asked to place their hands in either ice water (pain) or warm water (fake) for one minute. Their facial expressions were recorded and played back for either the human observers or the CERT program. As mentioned, the humans were pretty much guessing whereas the computer was actually quite good at spotting the fakers.

I’m not sure how CERT’s pain-detecting abilities would be used in the real world. I’m envisioning mothers saying: “So, you can’t go to school because you have a stomach ache? We’ll see about that.”

Now for the answer. If, like me, you guessed that image B on the right was fake, you’re wrong. Image B shows the expression of real pain. It’s image A that’s fake.

Bartlett, M., Littlewort, G., Frank, M., & Lee, K. (2014). Automatic Decoding of Facial Movements Reveals Deceptive Pain Expressions Current Biology DOI: 10.1016/j.cub.2014.02.009.

Friday, April 4, 2014

An ancient case of cancer

We sometimes think of cancer as a disease of modern life, both because it can be caused by modern living conditions (smoking, pollution) and because it doesn’t usually manifest until later in life. If most of a population dies at a young age, they will probably never get cancer. Add this to the fact that it’s difficult to find archeological evidence of specific diseases and you have scant evidence for the early appearance of cancer.

That doesn’t mean that cancer wasn’t around. Scientists from Durham University and from the British Museum have found the remains of one young man who lived over three thousand years ago who almost certainly had cancer.

The man had lived in what is now Sudan and was most likely 25-35 years old when he died. As you can see in the graphic below, much of his skeleton was affected by cancerous lesions.


Dark areas indicate full preservation,
Light areas indicate fragmented areas,
Hatched areas are the bones affected by lesions.

By the way, this unfortunate individual is not the earliest example of cancer. A 6000 year old skeleton in Austria was discovered with signs of multiple myeloma. There have also been about 50 cancerous individuals described from ancient Egypt, a region that excelled both in body preservation and in record keeping.

Binder, M., Roberts, C., Spencer, N., Antoine, D., & Cartwright, C. (2014). On the Antiquity of Cancer: Evidence for Metastatic Carcinoma in a Young Man from Ancient Nubia (c. 1200BC) PLoS ONE, 9 (3) DOI: 10.1371/journal.pone.0090924.

Thursday, April 3, 2014

A new test for colon cancer

Worldwide, colorectal cancer is one of the most commonly diagnosed forms of cancer. In the U.S., it is the second leading cause of cancer-related deaths (behind only lung cancer), and kills about 50,000 people per year. Luckily, there is a screening test that can catch the disease early enough to treat it. Even better, that test could just get a whole lot less invasive.

The standard test for colon cancer is called colonoscopy. Not to put too fine a point on it, a long flexible tube containing a camera is passed through the anus into the large intestines. The entire colon is carefully examined for lesions or polyps, which are removed for biopsy. The test requires the complete emptying of the bowels prior to the procedure, which is generally agreed upon to be unpleasant.

Perhaps for this reason, nearly half of eligible patients avoid colon cancer screenings. Thanks to researchers from the Mayo Clinic, there may soon be an alternative. In partnership with Exact Sciences, the scientists have developed a new screening tool called Cologuard.

Cologuard tests stool samples for DNA changes associated with colon cancer. In the past, such tests were not sensitive enough to replace colonoscopy. However, new techniques in DNA detection and sequencing have made Cologuard a promising option.

The researchers recruited about 10,000 people between the ages of 50 and 84 for their study. Each person provided a stool sample (no cleansing, dieting, or medication required) and subsequently underwent colonoscopy (with the usual cleansing).

By colonoscopy, 65 patients were found to have cancer. The DNA testing Cologuard identified 60 of them. That’s a pretty good success rate, and certainly better than other noninvasive tests.

Obviously, there is room for improvement, especially if Cologuard is meant to completely replace colonoscopy. However, if you consider that this test might get many more people screened, Cologuard could be an extremely useful tool in an oncologist’s arsenal. 

Imperiale, T., Ransohoff, D., Itzkowitz, S., Levin, T., Lavin, P., Lidgard, G., Ahlquist, D., & Berger, B. (2014). Multitarget Stool DNA Testing for Colorectal-Cancer Screening New England Journal of Medicine DOI: 10.1056/NEJMoa1311194.