Scientific American April 2011
The Latest in Science News
Forum: Rethinking the Dream (p 14)
Fifty years after Yuri Gagarin became the first human to travel into space on April 12, 1961, Lawrence M. Krauss reassesses the reasons why we send people into space.
Human space travel is dangerous and expensive-most of the huge cost goes into keeping humans alive during the process. Technology has progressed a lot since 1961, and robots have now been sent to places humans could never have survived in. Establishing a permanent presence on Mars, meanwhile, would cost many tens of billions of dollars-an inconceivable amount in the present economic climate.
"This is not to say that sending humans into space is entirely pointless," Krauss writes in the Forum section of this month's Scientific American. "If our species is to survive, our future will probably require outposts beyond our own planet." But before human space exploration can be reconsidered, "we are going to need all the creative thinking we can muster."
TechnoFiles: Seeing Forever (p 34)
Digital photos and videos are easy to use and access, but they won't last for our great-grandchildren to enjoy, David Pogue argues in this month's TechnoFiles column in Scientific American. Our memories will not be preserved by accident, as with prints and analogue formats in the past, but Pogue outlines the next steps for anyone who wants to ensure that all is not lost.
The conversion of photography, videography and literature to digital means instant access to our files. But formats do not endure: new computers cannot open early versions of common programs like Microsoft Word, and the same will be true for other formats. Consumer magnetic tape begins to deteriorate after about 15 years, so the time to convert old audio and video tapes to digital is right now. Then we need to commit to revisit recordings every 10 years. If digital files are to reach our great-grandchildren, they must be copied periodically "from one hard drive to the next and from there onto solid-state drives, then to nanotubes, then to brain implants-whatever the latest storage medium happens to be."
Science Agenda: Our Big Pig Problem (p 12)
The practice of using low doses of antibiotics to fatten up healthy farm animals should stop because it creates the breeding grounds for drug-resistant bacteria. Although farmers believe that restricting antibiotics would place unfair burdens on the industry and lead to significant cost increases for consumers, the threats to human health are much too high, the editors write in this month's Scientific American.
There are numerous studies that suggest that low doses of antibiotics in animals increase the number of drug-resistant bacteria in both animals and people. Taking this data into account, in Denmark, the government has banned the use of antibiotics as a means of fattening chickens, pigs and other farm animals. Although the first batches of pigs reared under the new system were smaller, farmers soon learned that they could fatten up the animals a different way-by leaving them with their mothers a little while longer. "The lesson is that improving animal husbandry-making sure that pens, stalls and cages are properly cleaned and giving animals more room or time to mature-offsets the initial negative impact of limiting antibiotic use," the editors argue. And in the end, depriving "drug-resistant bacteria of their agricultural breeding grounds simply makes scientific, economic and common sense."
Medicine: The Enemy Within (p 46)
A new type of drug resistance in a group of bacteria called the gram-negatives has emerged, threatening to make many common infections untreatable, Maryn McKenna writes in this month's Scientific American. Doctors and researchers have been monitoring the emergence of these resistant bacteria over the past decade, bracing for the tipping point, when "people in hospitals and in the wider community could die of newly untreatable gram-negative infections of the urinary tract, blood and other tissues."
Since penicillin's emergence in the 1940s, different groups of bacteria have evolved to be resistant to antibiotics. But new drugs, such as carbapenems-a group of so-called last-resort antibiotics-were developed to fill this resistance gap. To researchers'surprise, McKenna notes, the new types of gram-negative bacteria have developed genes that confer resistance even against carbapenems.
Carbapenem resistance in gram-negative bacteria is especially worrisome since unlike gram-positive bacteria, these bacteria easily share their genes with other types of bacteria, thus spreading the resistance genes to those other types. Last November the World Health Organization called the global dissemination of carbapenem resistance genes a "public health event of international concern," and yet there are no new drugs in development against these bugs.
Seismology: Seconds before the Big One (p 74)
Forecasting where and when the next big earthquake will hit has been an unattainable goal of many seismologist and geologists. As Richard Allen writes in this month's Scientific American, all is not lost: by integrating sensitive detection methods with modern communications technologies, authorities could receive tens of seconds of warning before an earthquake strikes.
Within seconds of the subtle shaking from an earthquake, scientists can use the amplitude and frequency of the preliminary waves to predict with some certainty how strong and widespread the shaking and rolling will be. Through a network of seismometer stations that gauge for high amplitude ground shaking, countries like Mexico and Japan transmit warning messages to authorities to shut down power plants and railway stations, automatically open elevator doors and alert emergency crews. Mexico's system, which came online in 1993, was able to pick up tremors and give authorities in Mexico City a 50-second warning before an 8.0 earthquake struck in 1995. In Japan, radio and TV stations, as well as cell phone providers, are linked into the seismic stations, sending users a message warning about the predicted location and intensity of an upcoming earthquake.
In California, such a network of seismic stations and warning systems could invariably save lives, costing the state an estimated $80 million.
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