Recent Interesting Science Articles (April ’10)Friday, May 7, 2010 17:35
A little late this month because I chose to write something about Ip Man 2 first this week. Four articles this time around with three of them on biology and the last one on astronomy. We’ll start with the more innocuous of the three biology articles first.
This is an article that appeared in Discover and concerns itself with gut bacteria, specifically those found inside of Japanese people. The Japanese as we all know, eat quite a lot of sushi and one of the main ingredients of sushi is seaweed. What most of us probably don’t know is that sea algae such as seaweed is a bit different from land-based plants and contain special sulphur-rich carbohydrates that are difficult for most of us to digest.
The Japanese however are able to digest them because the gut bacteria inside their intestines possess genes that most other people don’t have which help to break down the complex molecules. What’s interesting here is that these genes originate from a marine bacterium. Jan-Hendrik Hehemann of the University of Victoria has traced the voyage of how these genes ended up in the guts of the Japanese.
Since this bacterium feeds on seaweed as well, the ancestors of the Japanese must have swallowed them as well whenever they ate sushi. As the species intermingled with the other bacteria already present inside the intestines, they exchanged genes, eventually giving the Japanese the ability to digest seaweed. This is then passed down from mother to child as mothers are known to be able to pass down their microbiomes to their children.
Unfortunately to us non-Japanese, we’re not likely to ever gain this ability even though sushi has now spread all over the world. One reason is that the exchange of genes is a rare event that would take a long time to replicate. The second reason is that the Japanese used to make sushi with raw seaweed, ensuring that the bacterium was still alive when it entered the guts of the ancient Japanese. Nowadays, sushi is made with roasted seaweed, so there’s little chance of coming into contact with the live marine bacteria.
The next article is from The Economist and is about sexual attraction, something that is often the primary subject of many of the articles I’ve highlighted. This one talks about a study by Ben Jones and Lisa DeBruine of Aberdeen University, in Scotland on how economic development is changing which physical traits in men are attractive to women. Traditionally, the epitome of male sexual desirability is what the researchers label the Hercules look: craggy, muscle-bound masculinity. These traits are attractive because they imply that the male is able to protect and care for his mate while passing down genes that should result in a stronger immune system to the offspring.
However, to the women at least, the Hercules type also comes with a downside: such men are more promiscuous and tend to abandon families, leaving the women to raise the children on their own. This lead the researchers to suspect that as the prevailing situation in a society changes, the relative attractiveness of these traits should change as well. To test this, they arranged for 4,800 women from 30 countries to rate the attractiveness of 20 pairs of faces, which were actually masculinised and feminised versions of the same features, and analyzed the results.
What they found, after controlling for a variety of factors, was that women from countries with high disease rates strongly preferred the masculinised faces while women from healthier countries preferred the feminised ones. The implications are obvious: if you’re a big and tough guy, you should travel to poorer countries to attract more women. If you’re a wimpy guy, you need to head for the rich countries.
Next up is an article from Discovery News that is easily the most controversial of the lot. It covers findings from scientists from MIT, Harvard University and Beth Israel Deaconess Medical Center about how magnets are able to manipulate the moral judgment of test subjects. They used functional magnetic resonance imaging to locate an area of the brain that has previously been established as being related to moral judgments. They then directed a powerful magnetic field towards this portion of the brain of test subjects who were reading specially prepared texts.
The texts presented the test subjects with a situation for which they needed to decide whether or not the characters in it acted morally or not. The key to the exercise was that some of the situations presented bad outcomes, so the subjects needed to determine the morality of the characters based on their intentions instead of the outcomes. The scientists found that without the influence of the magnetic field, the subjects were consistently able to focus on the intentions of the characters, giving the story a good morality rating even if the outcome was bad as long as it was clear that the character involved had no evil intentions.
On the other hand, with the magnetic field in place confusing the neurons in the targeted area of the brain, the subjects tended to rate the morality of the stories based on outcomes rather than perceived intentions. Naturally this has obvious implications on the nature of morality but readers will be reassured that the process does not permanently damage the subjects’ sense of morality, or so the scientists claim anyway.
The last article goes into the “not really new science but simply plain awesome” category. It’s a report that appeared in The Daily Galaxy about the largest explosion yet observed by humanity: a super-supernova involving a super giant star two hundred times the mass of our own sun. In fact, the explosion was so massive that even though astronomers first noticed it two years ago, it is visible today.
This is apparently a relatively rare type of supernova caused what what they’re calling a “pair-instability” breakdown that leaves nothing behind, no black holes or neutron stars, but an expanding cloud of radioactive dust. Despite my googling, I was unable to find out how far away this SN1998bw supernova is from our solar system, but according to the article, it would have had catastrophic effects on Earth if it had happened at distances closer than about 100 light years away.