Category Archives: Scientific American

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Health Benefits of Bike Sharing Depend on Age, Gender

In the middle of the evening rush hour last November 29 more than 1,000 London cyclists staged a “die-in” to protest the traffic deaths of fellow riders and to demand more investment in bike-friendly roads. London’s streets may have grown friendlier to cyclists since the 2010 introduction of its Barclays Cycle Hire bike-sharing system but according to those at the protest, London is still too dangerous. The hundreds of cities that have launched bicycle-sharing systems in the last decade offer similar reasons for doing it: Bicycling reduces car traffic and pollution in city centers and is healthy exercise. But although all road-users benefit from less-crowded streets, a recent study suggests that the health benefits of bike-sharing programs depend on who is doing the riding.London’s bike-sharing program had registered 191,702 users at last count. Public health researcher James Woodcock at the University of Cambridge in England and his colleagues imagined, and calculated, how those riders lives might have been different had they not used the bikes. They examined data from 2.1 million hours of use between April 2011 and March 2012 and compared the health impact of those 2.1 million hours with the alternatives: more walking, public transit use or driving. To their surprise, the team reports in the February 13 BMJ (British Medical Journal), the switch to cycling may not have been helpful for young women. The health benefits also seem to differ by age, with older riders of both genders gaining more benefits than younger ones.

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Train of Thought Derailed: How an Accident Can Affect Your Brain

My cousin Guillermo Cassinello Toscano was on the train that derailed in Santiago de Compostela, Spain, last week when it went around a bend at twice the speed limit. Cassinello heard a loud vibration and then a powerful bump and then found himself surrounded by bloody bodies in wagon number nine. Shaking, he escaped the wreckage through either a door or a hole in the train—he cannot recall—then sat amid the smoke and debris next to the track and began to cry. Seventy-nine passengers died. Continue reading

Spanish High-Speed Train Crash Offers Safety-System Lessons

The driver of the high-speed train that derailed July 25 at a sharp curve in Santiago de Compostela, Spain, killing at least 80 passengers and injuring 130 more, told controllers he took the curve at around 190 kilometers per hour, despite an 80 kph speed limit. He survived the crash and is now under investigation by local authorities. Even if the driver turns out to have been responsible for speeding, rail passengers might wonder what else had to fail in the safety system to allow one man’s error to harm so many people. Continue reading

Faux Fossils

cover_2013-06On its way from flight to fossil, an ancient beetle’s wings lost their color and then their form. Slow-baked and squished by sand, the glittering green wings darkened and turned blue, then indigo, then black.

That tale of an insect’s life, death and fossilization sounds simple enough, but it took paleobiologist Maria McNamara years of painstaking work to piece together. The University of Bristol researcher wanted to know how ancient insects’ warning signals, camouflage and mating displays evolved. Studying ordinary fossils tells only part of the story, since most fossilized insects are black today, probably because they lost their colors while buried underground. Continue reading