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Scientific American - Objets Actus

Cocaine Addiction Stems from Desire, Not the Drug
Jeudi 02 Octobre 2008 - 22:00 - 1 mois, 4 semaines depuis - Presse spécialisée - Scientific American
Scientists know that addictive drugs can mess with the brain’s circuitry and hijack its reward systems, but a July 31 rat study in the journal Neuron shows that psychological factors may be more instrumental in causing these changes than a drug’s chemical effects are. Cocaine use triggers long-lasting cellular memories in the brain, the study found--but only if the user consumes the drug voluntarily.A team led by Billy Chen and Antonello Bonci, both at the University of California, San Francisco, trained three groups of rats to press levers that delivered cocaine, food or sugar. The researchers injected cocaine into a fourth group. When they examined the rats’ brain tissue, they found an increase in synaptic strength within the reward center in those rats that had self-administered sugar, food or cocaine. These cellular memories were short-lived in the sugar and food groups, but in rats that had self-administered cocaine they persisted for up to three months after consumption had stopped. Most interestingly, the brains of rats that had consumed cocaine involuntarily did not show such imprints. [More]

Presidential Elections Up Car Crashes
Mercredi 01 Octobre 2008 - 22:02 - 2 mois depuis - Presse spécialisée - Scientific American
[The following is an exact transcript of this podcast.]This presidential election will likely have a huge effect on health care. But it also will probably have a direct effect on public health. Because there’s a higher risk of injury and death from traffic accidents on presidential election days. Thanks to more people driving, many of whom probably shouldn’t be behind the wheel, and going to possibly unfamiliar destinations. That’s according to a study in the October 1st issue of The Journal of the American Medical Association. [More]

Ask the Brains: Why Do We Laugh When Someone Falls?
Mercredi 01 Octobre 2008 - 22:00 - 2 mois depuis - Presse spécialisée - Scientific American
Why do we find it funny when someone falls down?--William B. Keith, Houston [More]

The Power of Words
Mardi 30 Septembre 2008 - 22:00 - 2 mois depuis - Presse spécialisée - Scientific American
Psst. Have you heard the latest thing about him? And what she said about it?Chances are you’d be dying to know about that delectable tidbit of gossip offered by a confidant. We just can’t seem to get our fill of such morsels about other people in our social circles. [More]

12 Ways to Lessen Your Footprint
Mardi 30 Septembre 2008 - 22:00 - 2 mois depuis - Presse spécialisée - Scientific American
1. Mow Down EmissionsBattery-powered push mowers have been on a roll in 2008. Cut the grass, then plug your mower into a standard wall outlet to recharge it. The emissions savings can be substantial: according to the Environmental Protection Agency, running a typical two-stroke, gasoline-powered push mower for an hour creates as much pollution as driving a typical sedan for four hours. [More]

A Switch to Turn Off Autism?
Jeudi 25 Septembre 2008 - 12:00 - 2 mois, 1 semaine depuis - Presse spécialisée - Scientific American
Scientists say they have pinpointed a gene in the brain that can calm nerve cells that become too jumpy, potentially paving the way for new therapies to treat autism and other neurological disorders. [More]

Steroids Enhance Athletes for Years
Mercredi 24 Septembre 2008 - 22:01 - 2 mois, 1 semaine depuis - Presse spécialisée - Scientific American
[The following is an exact transcript of this podcast.] [More]

Mooove Over Cows?--Soy Milk May Be a Healthier Alternative
Mardi 23 Septembre 2008 - 09:15 - 2 mois, 1 semaine depuis - Presse spécialisée - Scientific American
Dear EarthTalk: There seems to be a large selection of soy and other non-dairy milks out there today, even right in the dairy sections of major supermarkets. Why should I opt for soymilk over cow’s milk and how do I get the calcium I would lose?-- Barbara Conant, Tacoma, Washington [More]

Good Bacteria against Type 1 Diabetes
Lundi 22 Septembre 2008 - 22:01 - 2 mois, 1 semaine depuis - Presse spécialisée - Scientific American
[The following is an exact transcript of this podcast.] [More]

Seven Years Later: Electrons Unlocked Post-9/11 Anthrax Mail Mystery
Vendredi 19 Septembre 2008 - 14:20 - 2 mois, 1 semaine depuis - Presse spécialisée - Scientific American
When materials scientist Joseph Michael and his team at Sandia National Laboratories in Albuquerque, N.M., trained their high-powered electron microscope on anthrax spore samples the FBI had sent them in February 2002, they made two crucial discoveries: The first confirmed previous findings that the Bacillus anthracis spores mailed to U.S. Senate offices and various media outlets (shortly after the September 11 terrorist attacks) contained silicon, a substance used to turn anthrax-causing spores into a biological weapon.But it was Sandia's next discovery that marked a critical turning point in the feds's probe of the mysterious mailings, which killed five people, injured 17 and prompted thousands more who were potentially exposed to the deadly spores to take potent antibiotics--in particular, Ciprofloxacin (known to irritate the gastrointestinal tract and cause joint swelling). Using highly sensitive transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM), the researchers came to a startling realization: The silicon had grown organically inside the Bacillus anthracis samples, nothing had been added to weaponize the spores. "The silicon was not on the outside of the spore," says Michael, who headed up Sandia's investigation, "but rather incorporated on the inside." [More]

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