How Birds Can Make Better Lasers

#NatureAndTechnology
When we think of parrots and toucans, images of bright and vivid feathers come to mind. It comes as no surprise, then, that these vibrantly colored feathers have attracted the attention of physicists trying to create a better kind of laser. Professor Hui Cao from Yale is at the head of this research group looking towards bird feathers for inspiration.

In the simplest form possible, laser technology involves bouncing light back and forth between two mirrors. In between the two mirrors lies a gain medium that amplifies a particular wavelength of light, and after many passes through the medium, the light gains power and is projected outward in a laser beam. Large amounts of research have gone into maximizing the number of times light bounces back and fourth inside the gain medium, thereby creating a more powerful laser output.

One technique involves drilling holes in specialized glass, creating an array of holes in random positions. When light travels through these randomly placed holes in the glass, it can bounce back and fourth many times between holes, and effectively gain a large amount of power before being emitted as as laser beam. The downside to this approach is that the process is very random and greatly inefficient. Here’s where the birds come in.

Brightly colored bird feathers take advantage of bouncing and amplifying light. In the feathers of brightly colored birds, air pockets exist at the nano scale level and bounce light back and fourth many times before being emitted out through the air pockets. Additionally, the air pockets in bird feathers are specifically tuned to amplify the wavelengths of light most characteristic of their feathers. It seems that though the position and placement of these air pockets appear random, at a smaller scale the air pockets are ordered in a very specific way. Professor Cao found this method of light amplification was not only efficient, but also modifiable. By changing the distance between the holes, the research team could change the color of light being amplified by the system. By studying a natural system of light amplification, Professor Cao and her research team have found a way to create more powerful and controllable lasers.

For more information, check out the publication here:

http://prl.aps.org/abstract/PRL/v106/i18/e183901

-Michael Rosario

First Science Cafe

First Science Cafe, a set on Flickr.

Pictures of the first ever Science Cafe are up!!!

The Sniff Test

Welcome to “The Sniff Test,” a semi-monthly column in which we examine extraordinary claims made by science journalists and compare these claims to the evidence actually presented in the relevant publication. We will attempt to be as educational as possible, but excuse us as we work out the kinks in our first few posts.

First up: are fifth-graders cheating off ants in math class? If not, should they be? Setting aside the ethical dilemmas, this seems like a logical follow-up question to a recent story put out on April 11 by Discovery News, “Are ants smarter than fifth-graders at math?” I guess, on the one hand, this title may be a humorous reference to the FOX show that probably inspired it. On the other, it seems like it could be a bit of a stretch, considering the content standards for fifth grade math. The article itself describes a recent review published¹ by Z. Reznikova and B. Ryabko in the journal Behaviour (and a related report published² in Electronic Transactions on Artificial Intelligence). The research shows apparent counting and arithmetic abilities in a wood ant species, Formica polyctena. Scouts were placed in a food-containing trough and navigated back to their group. Here, they had to transmit information about the location of the food, and then they were removed from their group, so that the foragers had to find the correct trough using only the information transmitted by the scouts. The researchers attempted to remove any means of information transfer except for communicating numerical quantities (e.g. they replaced the experimental apparatus to remove odors and odor-trails). At the very least, the authors showed fairly convincingly at least a type of counting ability in the ants. Whether they performed actual arithmetic is debatable, but their evidence is suggestive. All in all, pretty cool research. Not only does this species seem to possess some numerical faculty, but the way in which individuals communicate the location of food to each other seems to be a remarkable ability.

The Discovery News article does a decent job of distilling some of the main concepts of the research. However, some of the language used seems to oversell the work. First, the title itself seems clearly overblown, though admittedly, it seems to have been inspired by a press-release put out by the publisher of the Behaviour paper itself; we don’t need scientific publishers contributing to sensationalism. Next, the first sentence says that the study suggests “ants are smarter than many grade-school kids, at least when it comes to math….” However, the researchers say no such thing in either of their papers. Instead, they suggest that some ants’ numerical abilities may be on par with a very restricted subset of human abilities, and even this clearly applies to a narrow subset of human cultures and developmental stages. In the last paragraph of the article, the author discusses some of the other species reviewed in the scientists’ work (birds, mammals, etc.). She mentions that high numerical aptitude in pigeons, crows, and parrots must carry over to other birds, because these three species simply may be relatively easy to study. This could be a reasonable suggestion (though crows and parrots, for example, are known to be exceptional rather than ordinary as far as avian intelligence goes^{3, 4}), but it seems more appropriate for an opinion piece, rather than a report on research results—the research papers themselves never try to extend these results to all birds. Finally, while the research reports make clear that their results on Formica polyctena likely only extend to other highly social ant species, the Discovery News article makes it seem as if the research can be applied broadly across ants. A small point, but one not to be taken lightly; the question of how generalizeable research should be is one that crops up repeatedly.

In sum, based on the title and some of the sensationalist language, this article does not quite pass “the sniff test.” The results of the exciting research being covered should be allowed to stand on their own; the article instead seems to detract from the thought-provoking science being done.

References

1. Reznikova, Z. and Ryabko, B. 2011. Numerical competence in animals, with an insight from ants. Behaviour 148:405-434.

2. Reznikova, Z. and Ryabko, B. 2001. A study of ants’ numerical competence. — Electronic Transactions on Artificial Intelligence. 5: 111-126.

3. Emery, NJ. and Clayton, N.S. 2004. The mentality of crows: convergent evolution of intelligence in corvids and apes. Science 306:1903-1907.

4. Huber, L. and Gajdon, G.K. 2006. Technical intelligence in animals: the kea model. Animal Cognition 9:295-305.

-Tom Eiting

Science Cookies!!!

As a lover of both science and cookies, I was blown away by Not so Humble Pie's collection of science cookies. Below are a few of my favs, but be sure to check out her site for more inspiration!!!

This labware is not approved by EH&S but it is approved by me!

Nerves, delicious nerves!

So beautiful, so edible!

My God! I think they have finally sequenced the gene for yumminess!

-Skye Long

Blood Sucking Freaks!!!!!! Part 3 of 4

Sleep tight, don’t let the bedbugs bite…………or you will die???????

With all the chatter about bed bugs you would think these things carry the plague, but actually they do not transmit any disease to human hosts. This is pretty strange if you think about it, most human parasites that consume blood are vectors to some pretty nasty stuff. Mosquitoes transmit Malaria, Encephalitis, West Nile Virus, Dengue fever and Yellow fever and are responsible for over one million deaths worldwide per year! Ticks also carry devastating diseases, such as Lyme disease and Rocky Mountain Spotted Fever. If you want to get your 2011 Hypochondria a kick start see the CDC page on tick borne diseases. I feel itchy, and I might have a fever.

 Scientists don’t know why bedbugs don’t carry disease, though I am sure the National Institute of Health would give you money to find out. Hint, hint future grad students. And actually it could be a pretty interesting story; bedbugs have been co-evolving with us for thousands of years, just like mosquitos and ticks. So, why are they forces of pestilence and bedbugs aren’t?

                They may not carry any disease, but they can leave you covered in itchy red bumps and their shed exoskeletons can cause allergic reactions. Most clinicians agree that a lot of damage comes from the psychological trauma of being feasted on while you sleep. For a very emotionally damaging story about a bedbug infestation that will have you combing your mattress with a magnifying glass and tweezers Monk style, listen to This American Lice, oops, Life episode 361: Fear of Sleep. If you are still not examining every red bump on your body with enough bedbug fervor see the 2006 thriller “BUG”. Your neuroses will thank me.

After they die, blood-sucking insects are sorted according to thier ability as disease vectors.

Leaving it all behind: autotomy in animals

Surviving from predation is one of the most critical tasks for an animal. There are a number of ways to achieve this goal. One is to make sure that predators never gets you. As a result, some animals evolve superior locomotor ability to run away from predators, whereas others evolve astonishing camouflage so that predators can’t even find them. However, if a predator does get a grip on an animal, does that mean it is doomed? Well, in some cases there might still be some hope. Some animals can voluntarily discard certain body parts when it is caught by a predator. Which body part is disposable, however, varies among species. Some animals, such as insects and spiders, can discard their legs; other animals, such as lizards, can shed their tails. This amazing phenomenon, which biologists named it autotomy, provides the animal with a last-minute way of escape. You might wonder if the animal loses the body part forever after autotomy. Fortunately, the lost body part can be regenerated within a relatively short period of time. 

 

-Chi-Yun Kuo

What? Your petunias don’t talk to you?

So maybe it is a bit strange when your plants send you messages. But it is only a matter of time before communicating plants become our next weapon in the fight against terrorism. Professor Medford at Colorado State University and her team of biologists are modifying plant proteins that react to specific chemicals. Once the receptors of the proteins are modified to react with the chemicals of choice, these proteins then activate physiological changes that modify the plant’s appearance rapidly, such as turning all of its leaves white. With this technique, flowers and ferns could send us visual signals when in proximity of trace bomb chemicals or toxins in the air. With funding from Darpa, the Office of Naval Research, and the Defense Threat Agency, Medford says it will only be about 4 years until these plants are used in airports instead of the backscatter technology we all love. Follow this link for the publication or click here for an interview with Medford.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0016292;jsessionid=9E6895D8F62E08DA00CA29E1E6705A22.ambra02

http://youtu.be/kObTt_dR7IM

- Michael Rosario