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Turbulence is a notoriously hard field to study, both experimentally and theoretically. It seems that it has been observed for the first time in space:

Turbulence can be studied on Earth easily by mapping such things as the density or velocity of fluids in a tank. In space, however, where we expect turbulence to occur in such settings as solar wind, interstellar space, and the accretion disks around black holes, it's not so easy to measure fluids in time and space. Now, a suite of four plasma-watching satellites, referred to as Cluster, has provided the first definitive study of turbulence in space.

You can read more here. The original article on PRL can be read here.

Posted by Naboj at 03:45 PM | Permalink | Comments (0) | TrackBacks (0)

A friend of mine, who is a regular jet-setter, was the first person to alert me to the fact that flying west is an easier way of traveling around the globe. This anecdotal evidence seems to be getting some solid scientific backing. A group of scientists has tested it on mice, and it turns out that there was some significant effect on the health of mice who were exposed to the jet-lagged light conditions in the laboratory:

Despite the fact that trans-meridian travel and shift work are commonplace in our 24/7 society, few controlled studies have addressed the health effects of repeated phase shifts of the biological clock. Shift work and chronic jet-lag reduce mental acuity and increase the risk of a number of medical problems, including cancer, peptic ulcers and sleep disorders. Some of these problems become more severe with the number of years on the job, the result either of cumulative damage or the increased age of the subjects [3]. In general, morbidity associated with many organic disorders is increased in the aged; however, the role played by age-associated alterations in the circadian clock is poorly understood. In particular the effect of repeated schedule changes is largely unaddressed. Here we report evidence that chronic jeg-lag increases mortality rates in aged mice.

The full article can be found here (subscription required).

Posted by Naboj at 09:29 PM | Permalink | Comments (0) | TrackBacks (0)

The preference of human males for younger females is almost proverbial. It is assumed that this is a byproduct of human reproductive cycle - because of the menopause, younger human females yield a larger reproductive advantage. This hypothesis has been indirectly tested by studying chimpanzees. These closest human relatives don't undergo menopause, and it turns out that male chimpanzees prefer older females. This research has been reported in the current issue of Current Biology.

Cross-cultural studies indicate that women's sexual attractiveness generally peaks before motherhood and declines with age. Cues of female youth are thought to be attractive because humans maintain long-term pair bonds, making reproductive value (i.e. future reproductive potential) particularly important to males. Menopause is believed to exaggerate this preference for youth by limiting women's future fertility. This theory predicts that in species lacking long-term pair bonds and menopause, males should not exhibit a preference for young mates. We tested this prediction by studying male preferences in our closest living relative, the chimpanzee (Pan troglodytes). We show that despite their promiscuous mating system, chimpanzee males, like humans, prefer some females over others. However, in contrast to humans, chimpanzee males prefer older, not younger, females. These data robustly discriminate patterns of male mate choice between humans and chimpanzees. Given that the human lineage evolved from a chimpanzee-like ancestor, they indicate that male preference for youth is a derived human feature, likely adapted from a tendency to form unusually long term mating bonds.

The full article can be read here (subscription required).

Posted by Naboj at 03:29 PM | Permalink | Comments (0) | TrackBacks (0)

Google's search index is one of the greatest treasure-troves of useful social science information, but so far it has largely remained off-limits to the general academic scientists. That seems to be changing, as they seem to be interested in sharing their information with the outside world.

Google's data are a potential social science gold mine, "both for observing social interactions in real time and also for measuring their consequences for individual and collective behavior," says Duncan Watts, a sociologist at Columbia University. The key is the electronic "cookie." As you browse the Internet, many Web sites such as Google's record a string of tex--the cookie--representing the identity of your computer. And when you use Google, its servers keep track not only of what you search for but also where you go next. People add new entries to this record at the rate of 200 million Web searches per day. This electronic record is key to Google's business model: Most of its $1 billion annual revenue comes from Internet advertising targeted to individuals.

The full article can be read at Science's website (subscription required).

Posted by Naboj at 05:00 PM | Permalink | Comments (0) | TrackBacks (0)

Human genetic makeup and variability are somewhat controversial topic. Now there is evidence that there is more genetic variability between different humans than previously thought.

Geneticists have generally assumed that your string of DNA 'letters' is 99.9% identical to that of your neighbour's, with differences in the odd individual letter. These differences make each person genetically unique — influencing everything from appearance and personality to susceptibility to disease.

But hold on, say the authors of a new study published in Nature. They have identified surprisingly large chunks of the genome that can differ dramatically from one person to the next. "Everyone has a unique pattern," says one of the lead authors, Matthew Hurles at the Wellcome Trust Sanger Institute in Cambridge, UK.

The sumary of the article can be read here. The original article can be read here.

Posted by Naboj at 02:27 PM | Permalink | Comments (0) | TrackBacks (0)