Science Made Cool

Fish Tales in Sushi Restaurants

Confessions first – I love sushi. But getting hedonistic pleasure from biting into a firm, cold piece of fish paired with salty-sweet vinegared rice doesn’t mean that I also want to be chowing down on an endangered animal. Unfortunately, according to a study published in PloS ONE last week, there’s a good chance that the fish inside my tuna roll came from an endangered or threatened species.

There are eight species of tuna in the genus Thunnus, any of which may be served up as sushi: yellowfin, bigeye, longtail, blackfin, albacore, as well as the threatened Pacific bluefin and northern bluefin, and the critically endangered southern bluefin. Conservation organizations urge consumers to avoid eating any kind of bluefin tuna, but unless your ahi is a slice of the light-fleshed albacore tuna, it’s hard to tell which species you’re getting on your plate. Tuna species look different from one another when they’re whole fish, but slice them into filets and they all look pretty much alike. People may want to avoid eating endangered types of tuna, but they can’t do it effectively unless they can identify the fish in the restaurant or the market. (They could, of course, give up eating all tuna. But few people are willing to push their convictions that far.)

Jacob Lowenstein and his colleagues at the American Museum of Natural History tackled this problem by developing a DNA barcode system for all eight species of tuna. By looking for small, species-specific differences in the DNA sequence for a single protein – an important mitochondrial enzyme called cytochrome c oxidase – they developed a key that could match the DNA from a piece of tuna with the species of fish it came from. They tested the accuracy of their method by collecting samples from the places where most people meet tuna – sushi restaurants.

Thanksgiving Turkey

Larry Witmer's lab at Ohio University focuses on the physiology and biomechanics of vertebrate heads. They dissect 'em, inject 'em, and compare 'em, all in an effort to understand how the complex structures inside a head work and how they evolved. One of their favorite tools is the noninvasive CT scan: when paired with 3D visualization software, the technique lets them see the how soft tissues wrap around bones without lifting a scalpel. 

This particular animation - made especially for Thanksgiving - shows you the blood vessels inside the erectile snood of the tom turkey. 

Prep and scanning of OUVC 10599 by William Porter. 

Further 3D viz and animation by Ryan Ridgely.

World Not Ending, Film At 11

Following a link from the redoubtable Phil Plait at Skepticblog, here's a wonderful presentation of why the 2012 nonsense is, well, nonsense. I don't mean to be piling on here, because there's nothing so pointless as telling ignorant crackpots that they are, indeed, ignorant crackpots. But there seems to be something unusually tenacious about the 2012 nonsense. Maybe it's the massive film marketing campaign, maybe it's the rebound cycle from the Y2K nonsense. My personal theory is that it's residual Christian eschatology bubbling up through post-Christian scientism and boutique-spirituality syncretism. 

Anyhow, the short version: it's bogus. But you knew that, didn't you?

 

Another Philadelphia Experiment

Actually, it's a Camden, N.J. experiment. Friday through Sunday I'll be a guest at Philcon 2009, the annual Philadelphia-area science fiction convention. If you want to savor my wit, erudition, and fashion sense, here's my schedule of panel discussions:

Friday, 7:00 p.m.:  FANTASY BASED ON NON-EUROPEAN SOURCES

Saturday, 3:00 p.m.:  SOCIAL CHANGES NO ONE SAW COMING

Saturday, 8:00 p.m.:  PLAUSIBLE ALIEN LIFE FORMS IN HARD SF

Sunday, 10:00 a.m.:  CLASSIC GAMES YOU WANT TO PLAY AGAIN

I'll also be running intermittent demonstrations of BONE WARS and PARASITES UNLEASHED! in the open gaming area if anyone would like to stop by.

Ordinary Ancient Mayans

From the redoubtable PhysOrg site comes this interesting news story about new discoveries in the ancient Mayan city of Calakmul.

No, they haven't dug up a mind-controlling alien crystal skull. And no, it doesn't have anything to do with Roland Emmerich's movie. In fact, it's about entirely ordinary stuff. Within a ruined pyramid, archaeologists discovered ancient murals depicting everyday life among the Mayans.

This is kind of a big deal. The ancient Mayans built palaces and temples of stone, covered with carvings and paintings, but their homes were wood and thatch. In the Central American jungles, an environment rich in insects, scavengers, and micro-organisms, that means the evidence of how normal people lived is pretty scarce. Abandon your hut and a year later it's gone.

We know the names of their kings, we have records of their astronomical observations and statues of gods, but very little information about how the vast majority of the people of ancient Yucatan lived. One can make educated guesses (essentially by subtracting everything post-1500 from the livestyles of modern Maya people) but this is the first good look at how the ancient Mayans did stuff when they weren't performing rituals or celebrating their kings' martial prowess.

We don't have to worry. Future civilizations curious about 21st Century America can dig into landfills and find everything they want to know.

Rude Mechanicals

Puck:     My mistress with a monster is in love.
            Near to her close and consecrated bower,
            While she was in her dull and sleeping hour,
            A crew of patches, rude mechanicals,
            That work for bread upon Athenian stalls,
            Were met together to rehearse a play
            Intended for great Theseus' nuptial-day.

And now some really mechanical mechanicals are performing A Midsummer Night's Dream at Texas A&M University. Robots are playing some of the parts -- the article doesn't say which roles, but I'm guessing some of the fairies, since it mentions flying 'bots. It's an experiment of sorts, to see how people react to robots in unusual situations. Interestingly, the robots got kind of banged up, because humans tend to think of robots as indestructible metal monsters rather than delicate machinery.
 

Saving Energy

I've been trying to save energy by burning more wood. It's an easy choice:  my house is surrounded by trees and if I didn't burn them for fuel I'd have to pay someone to take away the dead ones anyway.

But saving energy also uses energy. Yesterday I was splitting a log with wedge and hammer. I was using a hammer (made in China) to pound a wedge (made in India) to split locally grown wood in order to burn it in my stove (made in Canada). My chainsaw, happily, is a U.S.-made brand, though I expect at least some of its components come from abroad.

More Milk from Contented Cows

A couple of days after the swank, tradition-filled IgNobel award ceremonies, the new laureates gather at MIT for the standing-room-only Ig Informal Lectures. During the awards ceremony each laureate gets only a minute for their acceptance speech, so the Informal Lectures are where they actually get the chance to explain themselves. They still have to be succinct: each lecture is only 5 minutes long, and Miss Sweetie-Poo lurks in the wings to cut off any laureate who heads into overtime. 

This year, the first speaker was Peter Rowlinson, one of the winners of the 2009 Ig Nobel for Veterinary Medicine. Rowlinson and his coauthor Catherine Douglas showed that cows that are named give more milk than cows that are only known as numbers. (Their work was published in the March 2009 issue of Anthrozoos.) It’s only a little more milk – a couple of liters on average – but in a large herd of dairy cattle it adds up. And that, he pointed out, translates to real money.

What If . . . ?

We all know about the Chicxulub impact -- the famous "dinosaur killer" asteroid which smashed into Yucatan 65 million years ago and ended the Cretaceous era with a bang. It may have had help. Paleontologist Sankar Chatterjee, of Texas Tech University, has identified another ancient crater he calls "Shiva," near modern-day Mumbai in India. The jury isn't quite in on Shiva yet -- so far no other researcher has confirmed Dr. Chatterjee's research -- but the prospect of two simultaneous dinosaur-killer impacts sets my science fiction writing organs twitching. Stand by for some completely wild speculation.