Friday, June 10, 2005

Appearance DOES Matter

Which person is more babyfaced?
Perspective in Science.
Take a look at these two snapshots. Which man is more babyfaced? Most viewers would say it's the person on the right. And that's the person who lost a 2004 U.S. congressional election to his more mature-faced and competent-looking opponent. In fact, about 70% of recent U.S. Senate races were accurately predicted based on which candidates looked more competent from a quick glance at their faces. This remarkable effect, reported by Todorov et al. on page 1623 of this issue, likely reflects differences in "babyfacedness". A more babyfaced individual is perceived as less competent than a more mature-faced, but equally attractive, peer of the same age and sex. Although we like to believe that we "don't judge a book by its cover," superficial appearance qualities such as babyfacedness profoundly affect human behavior in the blink of an eye.

Rapid Acidification of the Ocean During the Paleocene-Eocene Thermal Maximum

According to the wikipedia entry "The end of the Paleocene (55.5/54.8 Ma) was marked by one of the most significant periods of global change during the Cenozoic, a sudden global change, the Paleocene-Eocene Thermal Maximum, which upset oceanic and atmospheric circulation and led to the extinction of numerous deep-sea benthic foraminifera and on land, a major turnover in mammals."

report in Science. Summary:
A rapid and large global warming event, the Paleocene-Eocene Thermal Maximum (PETM), raised interior ocean temperatures by 4º to 5ºC around 55 million years ago, a rise not equaled in any single event since then. This warming, whose origin is still debated, was accompanied by a dramatic negative carbon isotopic excursion. One hypothesis is that the release of 2000 gigatons of carbon from the destabilization of methane clathrates on the sea floor account for both the carbon isotopic signal and the temperature increase. Zachos et al. (p. 1611) now show that the carbonate compensation depth (roughly the depth at which calcium carbonate is no longer found in the sediment, because of dissolution during sinking) of the ocean rose by more than 2 kilometers during the PETM, which could have happened only if the amount of CO2 added to the ocean was much more than that which has been estimated in the clathrate scenario. They find that 4000 gigatons of carbon would have been needed, so the release of clathrates alone could not have been the cause of the warming.

Art of Science Competition at Princeton

Anton Darhuber, Benjamin Fischer and Sandra Troian
Microfluidic Research and Engineering Laboratory, Department of Chemical Engineering
This image illustrates evolving dynamical patterns formed during the spreading of a surface-active substance (surfactant) over a thin liquid film on a silicon wafer. After spin-coating of glycerol, small droplets of oleic acid were deposited. The usually slow spreading process was highly accelerated by the surface tension imbalance that triggered a cascade of hydrodynamic instabilities. Such surface-tension driven flow phenomena are believed to be important for the self-cleaning mechanism of the lung as well as pulmonary drug delivery.

gallery page at Princeton.

DNA of Deadbeat Voles May Hint at Why Some Fathers Turn Out to Be Rats

Larry J. Young/Yerkes National Primate Research Center
Prairie voles on gels of their DNA, a possible clue to their home life.

Excellent article in today's New York Times.
Some male prairie voles are devoted fathers and faithful partners, while others are less satisfactory on both counts. The spectrum of behavior is shaped by a genetic mechanism that allows for quick evolutionary changes, two researchers from Emory University report in today's issue of Science.
People have the same variability in their DNA, with a control section that comes in at least 17 lengths detected so far, Dr. Young said.
The Emory researchers recently noticed that in their prairie vole colony, some fathers spent more time with their pups and some less. They traced the source of this variability to its molecular roots, a variation in the length of the DNA region that controls a certain gene.

This is the gene for the vasopressin receptor, the device used by neurons to respond to vasopressin. Voles with long and short DNA segments had different patterns of vasopressin receptors in their brains, which presumably changed their response to the hormone.

In Voles, a Little Extra DNA Makes for Faithful Mates news article in Science.
Prairie voles are renowned for being faithful mates, but some individuals are more faithful than others. The difference may lie in their so-called junk DNA.

... Elizabeth Hammock and Lawrence Young of Emory University in Atlanta, Georgia, report that fidelity and other social behaviors in male prairie voles seem to depend on the length of a particular genetic sequence in a stretch of DNA between their genes. The longer this repetitive sequence, or microsatellite, the more attentive males were to their female partner and their offspring. Those with shorter microsatellites neglected their mates and pups, at least to some degree.

Although there's no evidence that human infidelity or poor parenting stems from similar variations, Hammock and Young, as well as other researchers, have begun to explore whether microsatellites can account for behavioral differences between people and primates such as chimps and bonobos.

Microsatellite Instability Generates Diversity in Brain and Sociobehavioral Traits: the research article on vole genetics and behaviour in today's Science Magazine.

Here is Young's web page at Emory University