Another Inconvenient Truth: The World's Growing Population Poses a Malthusian Dilemma

By 2050, the world will host nine billion people --and that's if population growth slows in much of the developing world. Today, at least one billion people are chronically malnourished or starving. Simply to maintain that sad state of affairs would require the clearing (read: deforestation) of 900 million additional hectares of land, according to Pedro Sanchez, director of the Tropical Agriculture and Rural Environment Program at The Earth Institute at Columbia University. [More]


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Readers Respond on "Knowing Your Chances"--And More...

Unintentional Comedy I have been really enjoying your magazine since I started reading it last year.

Recommended: The Age of Empathy

The Sibley Guide to Trees by David Allen Sibley. Knopf, 2009 [More]


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Readers Respond on "Obama's Science"

Tax Dollars at Work Despite Barack Obama appointing scientists to top posts, I hardly think this qualifies him personally to be named in the “ Scientific American 10 .” His inclusion pales beside the favor bestowed to the others on the list who have actually done some real work for science and humanity. [More]


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Breast cancer deaths drop over past two decades

The number of women who die from breast cancer has decreased slowly (about 2 percent per year) but steadily since 1990, according to a new report by the American Cancer Society (ACS), released to mark the start of Breast Cancer Awareness Month. [More]


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Long-Awaited Research on a 4.4-Million-Year-Old Hominid Sheds New Light on Last Common Ancestor

The first full analysis of a 4.4-million-year-old early human paints a clearer picture of what the last common ancestor of humans and chimpanzees may have looked like, which is not, after all, that much like a chimp at all. The ancient Ardipithecus ramidus ("Ardi", as the most complete female specimen is known) is described in 11 research papers published online today in Science . The prodigious research effort combines Ardi's fossils with those from many other Ar. ramidus individuals--both male and female--found near the Awash River in the Afar Rift region of Ethiopia. [More]


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You Snooze, You Lose -- Weight

Lose weight while you sleep? It sounds too good to be true--but recent research indicates that there is a connection between how much you weigh and the amount of shut-eye you get per night.

Two hormones, ghrelin and leptin, help to control appetite. When you do not get enough rest, levels of ghrelin, which increases hunger, rise; levels of leptin, which promotes feelings of fullness, sink. A study in the May issue of Psychoneuroendocrinology found a significant disruption in nighttime ghrelin levels in chronic insomniacs. According to the study, this hormone imbalance leads insomniacs to experience an increase in appetite during the day, leading to weight gain over time.

What (Maybe) Didn't Kill the Dinosaurs: Comets

The chunks of ice and dust that make their home in the Oort cloud, far beyond the orbit of Pluto, sometimes become dislodged and head into the solar system as streaky comets. Some disruptions, caused by passing stars and other interactions with the Milky Way galaxy, are severe enough to send Oort comets into orbits that buzz or even collide with Earth. New simulations have revealed a novel mechanism for their entry into our part of the solar system, a method that also suggests that comet showers may not have been strongly involved in major extinctions on Earth.

Comet dynamics depend heavily on Jupiter and Saturn: their huge gravitational fields tend to keep objects away from Earth. Comets that manage to skirt Jupiter and Saturn, the conventional thinking goes, had to have originated in the outer reaches of the Oort cloud, where perturbations from outside the solar system can be felt most strongly and are writ large across vast cometary orbits that take hundreds of years to complete. Only during comet showers caused by close stellar passages, the theory holds, have extreme gravitational disruptions brought inner Oort cloud comets into the mix.

Odds Favor Drunk Trauma Victims

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

Being drunk might make you more accident prone, but it also increases your chance of survival. Research published in the journal American Surgeon reveals that trauma patients are more likely to survive if they were intoxicated at the time of their injury.

Gaming Tech Aids Scientists Building Virtual Synthetic Chromatophore

The study of processes that make life possible is hardly a leisurely pursuit, but that doesn't preclude researchers from taking advantage of the most advanced video gaming technology available to aid in their work. A team of University of Illinois at Urbana–Champaign (U.I.U.C.) physicists has assembled a supercomputer consisting of several hundred superfast graphics processing units (GPUs) --typically used for rendering highly sophisticated video game graphics--that they think will help them build a simulation depicting how chromatophore proteins turn light energy into chemical energy, a process called photosynthesis.

"Ninety-five percent of the energy that life on Earth requires are fueled by photosynthetic processes," says Klaus Schulten , a (U.I.U.C.) physics professor leading the simulation-building effort and director of the school's Theoretical and Computational Biophysics Group . To better understand how these processes work, Schulten's team is assembling a computer-based, virtual photosynthetic chromatophore . [More]


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The Dollars and Sense of Closing Schools for H1N1

Much has been made of the potential difficulties businesses face if numerous employees are out sick with the H1N1 "swine" flu . But there has been little information on the economic and other impacts if schools and day care centers continue to close temporarily to mitigate outbreaks. [More]


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Farmed Out: How Will Climate Change Impact World Food Supplies?

The people of East Africa once again face a devastating drought this year: Crops wither and fail from Kenya to Ethiopia, livestock drop dead and famine spreads. Although, historically, such droughts are not uncommon in this region, their frequency seems to have increased in recent years, raising prices for staple foods, such as maize. [More]


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Clean Energy Contest; and Counting Crickets and Katydids

The transcript of this podcast wil be posted in two to three weeks.

Scientific American podcast correspondent Cynthia Graber talks about the MIT Clean Energy Prize Competition. [More]


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Could a microchip help to diagnose cancer in minutes?

Current cancer screening often requires painful procedures and weeks of waiting to obtain results. But what if doctors could read a biological sample with a small hand-held device and come back with an answer in less than an hour? [More]


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Software mimics ant behavior by swarming against cyber threats

Looking to create computer defenses that adapt well to the cat-and-mouse game played between computer users and cyber attackers, a team of researchers has turned to one of nature's most effective militias--ants. Computer scientists at Wake Forest University in Winston-Salem, N.C., and the Pacific Northwest National Laboratory (PNNL) in Richland, Wash., are studying whether software written to behave like an army of "digital ants" can successfully find and flag malicious software (or malware). [More]


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Are Torosaurus and Triceratops one and the same?

A rare horned dinosaur known as Torosaurus may not be a distinct species after all, according to a presentation given Friday at the annual meeting of the Society of Vertebrate Paleontology in Bristol, England. [More]


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Teen Inventors Fight Tinnitus

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

Ever get a ringing in your ears after a loud blast of music on your iPod? That’s one example of the usually temporary condition called tinnitus, the sensation of sound even when no sound is being produced. But a new invention--created by high school students--may help.

New worm species found in unusual habitat: dead whale carcasses

Living whales may seem scarce in the world's vast oceans--and their carcasses even more rare. But to animals and bacteria that feed on these graveyards, they are a rich source of life. And to one doctoral researcher in Sweden, they proved to be a source of several new species.  [More]


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MIND Reviews: Neuro-Economic Boom

Does sex really persuade us to buy a product? Why do economies slip into depressions? And how much do we let our emotions influence our decision making? A spate of new books tries to answer these and other questions about how we make our choices, why they are sometimes so far off the mark and what their consequences are.

Animal Spirits--How Human Psychology Drives the Economy, and Why It Matters for Global Capitalism (Princeton University Press, 2009) examines the relation between economic fluctuations and psychological forces. Economists George Akerlof and Robert Shiller explore how “animal spirits”--the term coined by economist John Maynard Keynes to describe levels of consumer confidence--lie at the core of such questions as why there is unemployment and why minorities are often particularly poor.

50 Years Ago: Kidney Transplantation

OCTOBER 1959 FOUNDER OF KIDNEY TRANSPLANTS -- “Identical-twin grafts have demonstrated that where an immunological barrier does not exist kidneys can be successfully transplanted to cure otherwise incurable kid­-ney and vascular disease. We transplanted a kidney from a healthy man to his criti­cally uremic brother. Though the men were probably not identical twins, we hoped that their relationship might make for some immunologic compatibility. The recipient was given a total dose of X-rays large enough to depress his reticuloendothelial tissues severely. As the patient’s reticuloendothelial system recovers from the radiation, it may be forced to become familiarized with the antigens and the transplanted kidney. It is as yet too early to evaluate the results of this transplant, but initially it appears to be successful. -- John P. Merrill ”