Scientific American - Scientific American Mind

New Hope for Battling Brain Cancer (preview)

Mon, 01 Mar 2010 00:00:00 EST

In May 2006 Dwayne Berg woke up on a gurney in a Seattle emergency room, an IV in his arm and a team of doctors and nurses working him up. The last thing the 42-year-old financial executive could remember was running on a treadmill at his gym, part of his regular fitness regimen. He had suffered a seizure and tumbled off the machine, and although he had not hurt himself in the fall, doctors had asked for an MRI scan of his brain to see if they could find a cause for the seizure.

They did, and the news was not good: the scan showed a large mass in the left frontal lobe that turned out to be a malignant glioma, a brain cancer that is almost invariably fatal. Berg underwent standard treatment: an operation to remove the tumor, followed by chemotherapy and radiation to eradicate any cancer cells that might remain.

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Worm Charmers (preview)

Mon, 01 Mar 2010 00:00:00 EST

If you happen to be hiking in the right part of Florida at dawn, you might catch the sound of a predator hidden in the vegetation. Surely an alligator must be the source of these calls, you say to yourself. But the sound does not come from an alligator, or a mother bear, or some newly introduced predator from the Amazon. It comes from a human predator--a “worm grunter.”

Worm grunters have mastered the art of charming worms out of their burrows so they can be collected and sold as bait. First, the hunters pound a stob, or wooden stake, into the soil, and then they rub the stake with a flat piece of metal called a rooping iron. The vibrations resonate through the ground. In response, hundreds of large earthworms emerge, some as far as 12 meters from the baiter.

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The Brain and the Written Word (preview)

Mon, 01 Mar 2010 00:00:00 EST

Stanislas Dehaene holds the chair of experimental cognitive psychology at the Collège de France, and he is also director of the INSERM-CEA Cognitive Neuroimaging Unit at NeuroSpin, the most advanced neuroimaging research center in France. Dehaene is best known for his research into the cerebral basis of numbers, popularized in his book The Number Sense: How the Mind Creates Mathematics (Oxford University Press, 1999). In his new book, Reading in the Brain: The Science and Evolution of a Human Invention (Viking Adult, 2009), he describes his quest to understand an astounding feat that most of us take for granted: translating marks on a page (or a screen) into language. Mind Matters editor Gareth Cook recently talked with Dehaene about how the art of reading reveals the fundamental relationship between our cultural inventions and our evolved brain.

SCIENTIFIC AMERICAN MIND : How did you become interested in the neuroscience of reading?

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Toxic Gas, Lifesaver (preview)

Mon, 01 Mar 2010 00:00:00 EST

Imagine walking into a hospital emergency room, with its hand-sanitizer-adorned walls and every surface meticulously scrubbed free of contaminants, only to encounter the stench of rotten eggs. Distasteful though this juxtaposition might sound, the toxic gas synonymous with that smell--hydrogen sulfide (H 2 S)--may well become a fixture in such settings in the future. Over the past decade scientists have discovered that H 2 S is actually essential to a number of processes in the body, including controlling blood pressure and regulating metabolism. Our findings indicate that if harnessed properly, the gas could, among other benefits, help treat heart attack patients and keep trauma victims alive until they can undergo surgery or receive a blood transfusion.

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Evolution of Minerals (preview)

Mon, 01 Mar 2010 00:00:00 EST

Once upon a time there were no minerals anywhere in the cosmos. No solids of any kind could have formed, much less survived, in the superheated maelstrom following the big bang. It took half a million years before the first atoms--hydrogen, helium and a bit of lithium--emerged from the cauldron of creation. Millions more years passed while gravity coaxed these primordial gases into the first nebulas and then collapsed the nebulas into the first hot, dense, incandescent stars.

Only then, when some giant stars exploded to become the first supernovas, were all the other chemical elements synthesized and blasted into space. Only then, in the expanding, cooling gaseous stellar envelopes, could the first solid pieces of minerals have formed. But even then, most of the elements and their compounds were too rare and dispersed, or too volatile, to exist as anything but sporadic atoms and molecules among the newly minted gas and dust. By not forming crystals, with distinct chemical compositions and atoms organized in an orderly array of repeating units, such disordered material fails to qualify as minerals.

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Busting Big Myths in Popular Psychology (preview)

Mon, 01 Mar 2010 00:00:00 EST

Parts of this article are adapted from 50 Great Myths of Popular Psychology: Shattering Widespread Misconceptions about Human Behavior , by Scott O. Lilienfeld, Steven Jay Lynn, John Ruscio and Barry L. Beyerstein. Copyright © Wiley-Blackwell, 2010.

Popular psychology has become a fixture in our society, and its aphorisms, truths and half-truths permeate our everyday existence. A casual stroll through our neighborhood bookstore reveals dozens of self-help, relationship, recovery and addiction books that serve up heaping portions of advice for steering us along life’s rocky road. About 3,500 self-help books are published every year, and numerous new Internet sites on mental health sprout up every month.

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Fusion's False Dawn (preview)

Mon, 01 Mar 2010 00:00:00 EST

Ignition is close now. Within a year or two the 192 laser beams at the National Ignition Facility (NIF)--the world’s largest and most powerful laser system, a 13-year, $4-billion enterprise--will focus their energy onto a pellet no bigger than a peppercorn. Energy from the laser beams will crush the pellet’s core with such force that the hydrogen isotopes inside will fuse together and release energy, an H-bomb in miniature.

The trick has been tried before--and with success. But every time scientists have fused together these isotopes, they have had to pump far more energy into the lasers than the reaction spat out. This time the ledger will flip. The boom at the pellet’s center will release more energy than the lasers squeezed in, a switch more important than mere accounting would suggest. In theory, this excess energy could be collected and made to run a power plant. Its fuel would be materials found in ordinary seawater; its emissions--both atmospheric and nuclear--would be zero. It would be like capturing a star to run the machines of the earth. It would feed humanity’s endless thirst for energy, and it would do so forever.

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The Moon That Would Be a Planet (preview)

Mon, 01 Mar 2010 00:00:00 EST

If we had not known the images were coming back from Titan, we might have guessed they were new pictures of Mars or Earth. Some people in the control room saw the California coast, some saw the French Riviera, and one person even said that Saturn’s biggest moon looked like his backyard in Tucson. For three weeks, the Huygens probe had coasted, dormant, after detaching from the Cassini spacecraft and being sent on its way to Titan. Those of us watching anxiously felt a deep personal connection with the probe. Not only had we worked on the mission for a large part of our careers, but we had developed its systems and instrumentation by putting our minds in its place, to think through how it would function on an alien and largely unknown world. We imagined Titan might be like the comparably large moons of the outer solar system, such as Jupiter’s cratered Callisto or grooved Ganymede.

And so on the morning of January 14, 2005, at the European Space Operations Center in Darmstadt, Germany, the pictures caused jubilation and puzzlement in equal measure. None of us expected the landscape to look so Earth-like. As Huygens parachuted down, its aerial pictures showed branching river channels cut by rain-fed streams. It landed on the damp, pebble-covered site of a recent flash flood. What was alien about Titan was its eerie familiarity.

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The Pluses of Getting It Wrong (preview)

Mon, 01 Mar 2010 00:00:00 EST

For years many educators have championed “errorless learning,” advising teachers (and students) to create study conditions that do not permit errors. For example, a classroom teacher might drill students repeatedly on the same multiplication problem, with very little delay between the first and second presentations of the problem, ensuring that the student gets the answer correct each time.

The idea is that students who make errors will remember the mistakes and will not learn the correct information (or will learn it more slowly, if at all). Recent research shows that this worry is misplaced. Pupils actually learn better if conditions are arranged so that they have to make errors. Specifically, people remember things better and longer if they are given tests so challenging that they are bound to fail. This phenomenon has obvious applications for education, but the technique could be useful for anyone who is trying to absorb new material of any kind.

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A Sensory Fix for Problems in School (preview)

Mon, 01 Mar 2010 00:00:00 EST

To succeed in school, children must master the “three R’s”--reading, writing and arithmetic--but not all students readily grasp these basic skills. Among English-speaking children, an estimated 2 to 15 percent have trouble reading or spelling, problems broadly classified as dyslexia. From 1 to 7 percent struggle to do math, a disability known as dyscalculia. Statistics vary; dyslexia appears to be more common, for example, among English speakers than among speakers of highly phonetic languages, such as German or Italian. Nevertheless, it is fair to say that at least one child in most elementary school classes in the U.S. suffers from dyslexia or dyscalculia.

These learning disabilities defy easy explanation. Neither is the result of faulty eyesight or hearing, both of which can also delay language acquisition but are easily corrected using glasses or hearing aids. Instead children with dyslexia and dyscalculia have working sensory organs, apparently normal sensory and motor development and, sometimes, above-average intelligence.

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The Brain's Dark Energy (preview)

Mon, 01 Mar 2010 00:00:00 EST

Imagine you are almost dozing in a lounge chair outside, with a magazine on your lap. Suddenly, a fly lands on your arm. You grab the magazine and swat at the insect. What was going on in your brain after the fly landed? And what was going on just before? Many neuroscientists have long assumed that much of the neural activity inside your head when at rest matches your subdued, somnolent mood. In this view, the activity in the resting brain represents nothing more than random noise, akin to the snowy pattern on the television screen when a station is not broadcasting. Then, when the fly alights on your forearm, the brain focuses on the conscious task of squashing the bug. But recent analysis produced by neuroimaging technologies has revealed something quite remarkable: a great deal of meaningful activity is occurring in the brain when a person is sitting back and doing nothing at all.

It turns out that when your mind is at rest--when you are daydreaming quietly in a chair, say, asleep in a bed or anesthetized for surgery--dispersed brain areas are chattering away to one another. And the energy consumed by this ever active messaging, known as the brain’s default mode, is about 20 times that used by the brain when it responds consciously to a pesky fly or another outside stimulus. Indeed, most things we do consciously, be it sitting down to eat dinner or making a speech, mark a departure from the baseline activity of the brain default mode.

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Stopping Infections: The Art of Bacterial Warfare (preview)

Mon, 01 Feb 2010 00:00:00 EST

Most bacteria are well-behaved companions. Indeed, if you are ever feeling lonely, remember that the trillions of microbes living in and on the average human body outnumber the human cells by a ratio of 10 to one. Of all the tens of thousands of known bacterial species, only about 100 are renegades that break the rules of peaceful coexistence and make us sick.

Collectively, those pathogens can cause a lot of trouble. Infectious diseases are the second leading cause of death worldwide, and bacteria are well represented among the killers. Tuberculosis alone takes nearly two million lives every year, and Yersinia pestis , infamous for causing bubonic plague, killed approximately one third of Europe’s population in the 14th century. Investigators have made considerable progress over the past 100 years in taming some species with antibiotics, but the harmful bacteria have also found ways to resist many of those drugs. It is an arms race that humans have been losing of late, in part because we have not understood our enemy very well.

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The Power to Persuade (preview)

Mon, 01 Mar 2010 00:00:00 EST

“Nothing is so unbelievable that oratory cannot make it acceptable.” --Marcus Tullius Cicero

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"Impossible" Colors: See Hues That Can't Exist (preview)

Mon, 01 Feb 2010 00:00:00 EST

Engineers often load a structure with weight until it collapses or shake it until it flies apart. Like engineers, many scientists also have a secret love for destructive testing--the more catastrophic the failure, the better. Human vision researchers avoid irreversible failures (and lawsuits) but find reversible failures fascinating and instructive--and sometimes even important, as with the devastating spatial disorientations and visual blackouts that military pilots can experience. At the U.S. Air Force Research Laboratory, the two of us explore the most catastrophic visual failures we can arrange. We create conditions in which people see images flowing like hot wax and fragmenting like a shattered mosaic. Here, we tell the story of the two most intriguing perceptual breakdowns we have studied: forbidden colors and biased geometric hallucinations.

Have you ever seen the color bluish yellow? We do not mean green. Some greens may appear bluish and others may appear yellow-tinged, but no green (or any other color) ever appears both bluish and yellowish at the same moment. And have you ever seen reddish green? We do not mean the muddy brown that might come from mixing paints, or the yellow that comes from combining red and green light, or the texture of a pointillist’s field of red and green dots. We mean a single color that looks reddish and greenish at the same time, in the same place.

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Life at the Bottom: The Prolific Afterlife of Whales (preview)

Mon, 01 Feb 2010 00:00:00 EST

On a routine expedition in 1987, oceanographers in the submersible Alvin were mapping the typically barren, nutrient-poor seafloor in the Santa Catalina Basin, off the shore of southern California. On the final dive of the trip, the scanning sonar detected a large object on the seafloor. Piercing through the abyssal darkness down at 1,240 meters, Alvin ’s headlights revealed a 20-meter-long whale skeleton partly buried in sediment. On reviewing the dive videotapes, expedition leader Craig Smith and his team saw that the skeleton was probably either a blue or a fin whale. The creature appeared to have been dead for years, but the bones and their surroundings teemed with life--wriggling worms, centimeter-size clams, little snails and limpets, and patches of white microbial mats. The skeleton was a thriving oasis in a vast, desertlike expanse.

Almost a year later Smith, an oceanographer at the University of Hawaii at Manoa, returned for a proper study of the skeleton site. His team described several species previously unknown to science, plus some that had been observed only in unusual environments, such as at deep-sea hydrothermal vents.

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Mysteries of How a Star Is Born (preview)

Mon, 01 Feb 2010 00:00:00 EST

If there is anything you think astronomers would have figured out by now, it is how stars form. The basic idea for how stars form goes back to Immanuel Kant and Pierre-Simon Laplace in the 18th century, and the details of how they shine and evolve were worked out by physicists in the first half of the 20th century. Today the principles that govern stars are taught in middle school, and exotica such as dark matter dominate the headlines. It might seem that star formation is a problem that has been solved. But nothing could be further from the truth. The birth of stars remains one of the most vibrant topics in astrophysics today.

In the simplest terms, the process represents the victory of gravity over pressure. It starts with a vast cloud of gas and dust floating in interstellar space. If the cloud--or, more often, a dense part of such a cloud called a core--is cool and dense enough, the inward pull of its gravity overpowers the outward push of gaseous pressure, and it begins to collapse under its own weight. The cloud or core becomes ever denser and hotter, eventually sparking nuclear fusion. The heat generated by fusion increases the internal pressure and halts the collapse. The newborn star settles into a dynamic equilibrium that can last millions to trillions of years.

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Fixing the Global Nitrogen Problem (preview)

Mon, 01 Feb 2010 00:00:00 EST

Billions of people today owe their lives to a single discovery now a century old. In 1909 German chemist Fritz Haber of the University of Karlsruhe figured out a way to transform nitrogen gas--which is abundant in the atmosphere but nonreactive and thus unavailable to most living organisms--into ammonia, the active ingredient in synthetic fertilizer. The world’s ability to grow food exploded 20 years later, when fellow German scientist Carl Bosch developed a scheme for implementing Haber’s idea on an industrial scale.

Over the ensuing decades new factories transformed ton after ton of industrial ammonia into fertilizer, and today the Haber-Bosch invention commands wide respect as one of the most significant boons to public health in human history. As a pillar of the green revolution, synthetic fertilizer enabled farmers to transform infertile lands into fertile fields and to grow crop after crop in the same soil without waiting for nutrients to regenerate naturally. As a result, global population skyrocketed from 1.6 billion to six billion in the 20th century.

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Better Mileage Now--Improving the Combustion Engine (preview)

Mon, 01 Feb 2010 00:00:00 EST

Demand for automobiles is rising worldwide. So is concern about greenhouse gas emissions. In response, scientists and engineers are working diligently to perfect new power plants for future vehicles, including battery and hydrogen fuel-cell electric cars. Although these and other alternatives show great promise for the long term, perhaps the single greatest way to reduce fossil-fuel consumption in the near term is to further improve today’s dominant transportation power plant: the gasoline internal-combustion (IC) engine.

Fortunately, efficiency can be raised in a number of ways, notably, better control over the air-fuel mixture entering the combustion chamber, over the way gasoline is ignited there, and over the mechanical systems that harness that energy. These can improve traditional automobiles as well as gasoline-electric hybrid models.

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The Naked Truth: Why Humans Have No Fur (preview)

Mon, 01 Feb 2010 00:00:00 EST

Among primates, humans are unique in having nearly naked skin. Every other member of our extended family has a dense covering of fur--from the short, black pelage of the howler monkey to the flowing copper coat of the orangutan--as do most other mammals. Yes, we humans have hair on our heads and elsewhere, but compared with our relatives, even the hairiest person is basically bare.

How did we come to be so denuded? Scholars have pondered this question for centuries. Finding answers has been difficult, however: most of the hallmark transitions in human evolution--such as the emergence of upright walking--are recorded directly in the fossils of our predecessors, but none of the known remains preserves impressions of human skin. In recent years, though, researchers have realized that the fossil record does contain indirect hints about our transformation from hirsute to hairless. Thanks to these clues and insights gleaned over the past decade from genomics and physiology, I and others have pieced together a compelling account of why and when humans shed their fur. In addition to explaining a very peculiar quirk of our appearance, the scenario suggests that naked skin itself played a crucial role in the evolution of other characteristic human traits, including our large brain and dependence on language.

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Daring to Die: The Psychology of Suicide (preview)

Fri, 01 Jan 2010 00:00:00 EST

At age 18, Erica Hernandez tried to kill herself--twice. Depressed and plagued by family problems, she first took “every pill in the house,” she says. Then she attempted to drink herself to death. But whether through luck or indecision, her attempts were not drastic enough to end her life before help arrived. Now age 31, Hernandez has found “peace” through her church and a parent-child psychotherapy group she has joined.

Every year millions of people around the world try to kill themselves--and nearly one million of them succeed. Suicide is the 11th biggest killer of Americans and the third-leading killer of 15- to 24-year-olds. The U.S. suicide rate is increasing for the first time in a decade, primarily as a result of the rise in the practice among whites aged 40 to 64, according to a new report covering the years 1999 to 2005 from the Center for Injury Research and Policy at the Johns Hopkins Bloomberg School of Public Health. The economy is now adding to the problem: the chief financial officer of Freddie Mac killed himself last April, and so have some Americans who have been evicted from their homes. The U.S. government’s National Suicide Prevention Lifeline, begun in 2005, is also getting record numbers of calls: 57,625 in August 2009, up from 47,191 the same month a year before.

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