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CONTENTS FEATURES ■ SCIENTIFIC AMERICAN May 2010 Volume 302 Number 5 ■
ASTROPHYSICS
38 Through Neutrino Eyes
By Graciela B. Gelmini, Alexander Kusenko and Thomas J. Weiler
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Neutrinos are no longer just a curiosity of physics but a practical tool for deciphering features of the sun, supernovae and more. MEDICINE
46 Your Inner Healers By Konrad Hochedlinger
Meet the newest stem cells. Made by reprogramming cells from your own body, they could bypass ethical and technical problems raised by embryonic stem cells. TRANSPORTATION
54 Revolutionary Rail By Stuart F. Brown
New investments may finally bring high-speed trains to the U.S.
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NEUROSCIENCE
60 Uncanny Sight in the Blind By Beatrice de Gelder
Some people who are blind from brain damage have “blindsight”: an ability to respond to what their eyes detect without knowing they can see anything.
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CLIMATE CHANGE
66 Arctic Plants Feel the Heat By Matthew Sturm
Global warming is dramatically revamping not only the ice but also tundra and forests at the top of the world, greening some parts and browning others. INNOVATIONS
74 A Better Lens on Disease By Mike May
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Computerized pathology slides promise to help physicians give patients faster and more accurate diagnoses. FOOD SCIENCE
78 Breeding Cassava to Feed the Poor
By Nagib Nassar and Rodomiro Ortiz The world’s third-largest source of calories could be made more productive and nutritious, helping to alleviate malnutrition in many places.
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SCIENTIFIC AMERICAN
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ON THE COVER Stem cells potentially can be converted into any tissue needing repair. A newly invented type holds enormous promise for medicine. Illustration by Bryan Christie Design. M a y 2 0 10
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CONTENTS DEPARTMENTS ■ 6 8 12
From the Editor Letters 50, 100 & 150 Years Ago
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News Scan
12 14
RESEARCH & DISCOVERY ■ ■ ■
Generating mug shots from traces of DNA. Origin of Earth’s magnetic field timed to life’s start. Why the chameleon’s tongue works in the cold.
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MEDICINE & HEALTH ■ ■ ■
Refi ned carbs bad; saturated fat not so bad. Kidney donors live just as long as those with two. Intestinal microbes drive obesity.
ENERGY & ENVIRONMENT ■ ■
A common herbicide triggers sex changes. Climate errors prompt review by science academies.
TECHNOLOGY ■ ■
By the Editors
Sustainable Developments By Jeffrey D. Sachs
Complex policy issues need expert and public debate.
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Critical Mass
By Lawrence M. Krauss We must adjust to our unparalleled ability to shape the world’s evolution.
Perspectives Marketing unhealthy foods to kids should be banned.
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Skeptic
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Recommended
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Anti Gravity
Decoding weather. The universe. The pill.
By Steve Mirsky What if past giants of science had Twitter?
By Michael Shermer Comparative history helps to explain Haiti’s poverty.
GO TO .COM
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Consumer Electronics: More Than Just Fun and Games
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Video games, e-readers, smart phones and other gadgets have changed the way we interact with one another and with the world around us. What’s next? (Hint: Get used to those 3-D glasses.) More at www.ScientificAmerican.com/may2010
TIM PANNELL Corbis
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Forget genetic engineering? Fungi can modify crops. Better plastic bottle recycling via organic catalysts.
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