Scientific American

Dear EarthTalk: I am considering solar panels for my roof to provide heat for my hot water and possibly to do more than that. Are there some kinds of solar panels that are better than others? How do I find a knowledgeable installer? -- Elise, Watertown, MA

Good news for potheads making their annual trek to Black Rock, Nev., this week to celebrate Burning Man: A new study says that marijuana appears to fight infections. According to research published in the Journal of Natural Products, the five most common cannabinoid compounds in weed--tetrahydrocannabinol (THC), cannabidiol, cannabigerol, cannabinol and cannabichromene--can kill antibiotic-resistant bacteria. Think MRSA (methicillin-resistant Staphylococcus aureus), which claimed more lives than AIDS in 2007 or, more recently, extensively drug-resistant mycobacterium tuberculosis (XDR-TB.) [More]

Computer viruses--the scourge of technology on Earth--have now become a problem in space, too. NASA has confirmed that the malevolent programs have also posed problems in computers that astronauts bring with them on missions, the latest occurring when laptops infected with the Gammima.AG virus were ferried to the International Space Station (ISS) last month. The possible source, according to SpaceRef.com: a software download, a personal flash card or USB storage device. The site also reports that some laptops used in the ISS  lack virus protection and detection software. [More]

For the second year in a row, the fabled Northwest Passage has opened in the Arctic--thanks to a sea-ice melt that has already shrunk the polar cap to the second smallest extent ever recorded. And with a few more weeks to go in the summer thaw season, 2008 could surpass 2007 as the smallest amount of sea ice on record, according to the National Snow and Ice Data Center (NSIDC). [More]

[The following is an exact transcript of this podcast.] 

The plague is most famous for killing tens of millions of people all over Europe in the 1300s.  Plague is caused by the bacteria Yersinia pestis. And the disease still exists in pockets around the world. In fact, because it can be transmitted through the air, the government considers the plague a Category A bioterrorism agent and a serious potential threat. 

Veteran journalist Merrill Goozner, director of the Integrity in Science project at the Center for Science in the Public Interest, discusses his series of articles for SciAm.com on the rise of tuberculosis in Russia. Plus, we'll test your knowledge of some recent science in the news. Web sites mentioned in this episode include www.gooznews.com; www.snipurl.com/goozner

The text transcript is currently not available. Transcripts are posted about a week after the podcast airs.

As the pharmaceutical giant Pfizer was reminded in May, arriving first has its rewards, but they come with the risks of venturing into uncharted territory. This past spring the Federal Aviation Administration banned pilots and air traffic controllers from taking the company’s popular smoking-cessation aid, varenicline, which is sold in the U.S. as Chantix. Amid 6.5 million prescriptions written worldwide since 2006, the drug had spawned highly publicized reports of acute psychiatric episodes that included seizures, psychosis and suicidal depression. In May the nonprofit Institute for Safe Medication Practices documented 988 such “adverse events,” prompting the aviation ban.

The Food and Drug Administration has now added strong warning language to varenicline’s medication guide, and Pfizer is reviewing evidence that might help explain the rare but severe incidents. Although the bad publicity may dampen sales of the drug, observers say that some adverse events are not unexpected when a new drug hits the market, especially one that is the first of its kind. Varenicline is not just a novel smoking-cessation tool; it is the first of an entire class of medications specifically designed to target a powerful family of receptors on the surface of brain cells. Known as neuronal nicotinic acetylcholine receptors, they can mediate pain, mood, memory, attention and other cognitive functions.

Can one neuron release more than one neurotransmitter?--Marvin Shrewsbury, Wailuku, Hawaii

Planetary Protection RacketAs the first planet to form in our solar system, Jupiter helped to sculpt the rest [see “The Genesis of Planets”; SciAm, May 2008]. Because of its gravity, for instance, it has regulated the rate of cosmic impacts on Earth: flinging asteroids in our direction yet also clearing many hazardous space rocks out of our way. Jupiter’s net effect depends on its mass, suggest Jonathan Horner and Barrie Jones, both at the Open University in England, in an upcoming paper in the International Journal of Astrobiology. Had Jupiter one-fifth its mass, they calculate, it would have failed to clear asteroids out--and Earth might have been struck four times more often than it has been. But if Jupiter were still smaller, it would have flung fewer asteroids toward the inner solar system to begin with--and the dinosaurs might still be walking our planet.  --George Musser

Do you have an affinity for technology? Did you do well in civics class? Are you free on November 4? If you meet all of these criteria, then you might feel compelled to take a temporary job on Election Day this year as a volunteer election site worker or an electronic voting machine technician.

That's the message being sent out by groups concerned about the integrity of the upcoming presidential election as well as the e-voting technology that some states will rely on to cast votes. Election watchdog, Black Box Voting, based in Renton, Wash., this week issued a press release pointing out that voting machine vendors--including Election Systems & Software, Premier Election Solutions, Sequoia Voting Systems and Hart Intercivic--will hire and train thousands of technicians staffed around the country.

The first results from a powerful gamma-ray telescope launched into orbit earlier this summer show it is on track to unlock new secrets of the most energetic explosions in the universe. That was the message from NASA researchers speaking at a teleconference this afternoon to present the findings and to announce the mission's new name. [More]

Scientists have known since 2004 that wind farms kill bats, just as they kill birds, even though the flying mammals should be able to avoid them. Many biologists thought that the bats, like their avian counterparts, might be falling victim to the fast-spinning turbine blades. But an examination of 188 hoary and silver-haired bats killed at a wind farm in southwestern Alberta in Canada between July and September in 2007 showed that nearly half showed no external injuries--as would be expected if the giant blades had smashed the flying mammals to the ground. [More]

This hurricane season's seventh storm, Gustav, has already had a bigger impact than all the storms that preceded it. It hasn't killed anyone or done any damage--though it may unleash flooding and mudslides in Haiti--except to drive oil prices above $117 a barrel (a feat the recent war in Georgia did not even accomplish). [More]

The use of microchips to track people (such as those embedded in hospital wristbands) and products (those uncomfortable tags on clothing that have to be cut off prior to wearing) has come under fire from civil rights groups who claim that big corporations are using this technology as a tool for spying. But what about when these tags are embedded in people themselves, rather than the things they wear? [More]

"Drunken" trees listing wildly, cracked highways and sinkholes--all are visible signs of thawing Arctic permafrost. When this frozen soil warms, it releases carbon dioxide, methane and other greenhouse gases as microbes start to thrive on the organic material it contains--a potentially potent source of uncontrollable climate change. [More]

This is the third article in the Mind Matters series on the neuroscience behind visual illusions.

The eyes are the windows to the soul. This fact is why we ask people to look us in the eye and tell us the truth. Or why we get worried when someone gives us the evil eye or has a wandering eye. Our everyday language is full of expressions that refer to where people around us are looking. Particularly if they happen to be looking in our direction. 

[The following is an exact transcript of this podcast.] 

Don't be fooled by those big bovine eyes and the mouth slowly chewing cud--cows have a magnetic personality. At least that’s the claim made by German researchers in the August 26th issue of the Proceedings of the National Academy of Sciences. Using Google Earth images, the scientists looked down on over 8,000 cattle around the world. And, when grazing or resting, cows tended to face either magnetic north or south.

On the day Patricia Hunt’s career veered into an entirely different field, her graduate students at Case Western Reserve University were grumbling, itching to use some exciting new data in their own experiments, but were told to wait while Hunt (just one last time) checked on her subjects.

Hunt, a geneticist, was exploring why human reproduction is so rife with complications. She had a hunch the chromosomally abnormal eggs that plague human pregnancies were tied to our hormones. A paper outlining the results of Hunt’s experiments on the hormone levels of female mice was ready for publication. All she needed was to ensure that her control population, the mice left alone in the study, was normal. Instead Hunt stumbled on a disturbing result--40 percent had egg defects.

By picking Joe Biden as a running mate, Barack Obama may have reassured the electorate about his lack of experience and foreign policy bona fides, according to some pundits. But the coal-state senator may have also taken a step toward shoring up his enviro cred.

The Delaware senator is as serious as a heart attack about energy policy--a point The Wall Street Journal's Jeffrey Ball made this weekend.

Nearly three years ago, Cassidy's fate was uncertain. Missing his right hind leg, virtually hairless, and 30 pounds (14 kilograms) underweight, the year-old old German shepherd mix was living in an animal shelter in the Bronx when Steve Posovsky saw him on a morning television show segment about pets. "There were tears in my eyes," recalls Posovsky, who lives with his wife, Susan, in Long Beach, N.Y. He contacted the shelter and shortly thereafter welcomed Cassidy as a member of his family. Although Cassidy has managed well on three legs, the Posovskys are now hoping a new type of prosthetic will let the revitalized 75-pound (35-kilogram) dog run and jump like others that have a full complement of limbs. [More]