Feature

Science News of the Year 2002

By Science News

December 17, 2002 at 11:06 am

Researchers announced the discovery of a fossil skull representing the earliest known member of the human evolutionary family, which lived in central Africa nearly 7 million years ago . Other scientists argued that the skull instead comes from an ancient ape . Brunet/Nature

Sensitive X-ray, infrared, and radio telescopes are providing an extraordinarily clear view of the dust-shrouded center of our galaxy . This mosaic of X-ray images reveals hundreds of point sources at the Milky Way’s core, including white dwarf stars, neutron stars, and stellar-mass black holes. All are bathed in a fog of multimillion-degree gas that surrounds a supermassive black hole. Q. Daniel Wang, Univ. of Mass.

Reports of babies’ basic counting capabilities inspired a wave of new research and a spirited debate about infants’ number knowledge .

Understanding the dizziness that astronauts often feel after space flight may help explain orthostatic intolerance, a disorder in which patients get faint or dizzy while standing. Here, one astronaut monitors a test in which another astronaut (foreground, beneath tubes) lies in a device that produces negative pressure on the lower half of his body, mimicking the effects of gravity on blood flow. . NASA

Genetic studies suggested that people domesticated dogs in East Asia and brought them along when first venturing into the Americas . Other tests indicated that dogs have an innate sensitivity to humans’ body language as a legacy of domestication . E. Roell

Showing off a growing ability to guide the growth of lab-grown tissues, Salt Lake City scientists created this image of the Olympic rings from live nerve cells . University of Utah

Unlike the stainless steel that caps New York’s Chrysler Building, cheap grades of the rust-resistant alloy are prone to pit corrosion, in which small spots on the metal’s surface erode at accelerated rates. British researchers who analyzed various grades of stainless steel discovered that pit corrosion results from a dearth of chromium in the material that surrounds sulfide-rich inclusions in the metal .

Researchers analyzing satellite images of a remote island (large circle) off the northeastern coast of Greenland stumbled upon an undiscovered group of nearby small islands (small circle) . Mohr and Forsberg/Nature

The discovery that cooking and frying laces starchy foods with the animal carcinogen acrylamide launched an international effort to investigate how the poison forms and whether people’s current exposures pose risks .

To make the first antimatter atoms that move slowly enough to be studied, physicists combined ultracold antiprotons and antielectrons into atoms of antihydrogen. Such atoms annihilate (above) when they hit ordinary matter . Researchers also took a first, cursory peek inside antihydrogen and found matter and antimatter to be fundamentally alike, as expected . ATHENA Collaboration

A year of twists and turns

What the world needs, say some people, is more one-handed scientists. That way, reports would have fewer sentences starting, “On the other hand. . . .”

Actually, scientists need all the hands they can muster. Most of the phenomena they investigate are so complex that even carefully designed experiments can’t take into account all possible influences on the results. Change one condition–a chemical concentration, a nutritional state–and an experiment can yield dramatically different data. Or worse, factors that scientists haven’t even considered can turn out to be the main drivers. What scientists know for sure is that today’s conclusions may well be overturned by tomorrow’s data.

This frustrating aspect of science was magnificently demonstrated this year with the surprising findings of two trials of hormone-replacement therapy. Previous studies had convinced doctors to prescribe estrogen and progestin in supplements to millions of women, primarily to prevent heart disease. But in large, rigorously designed U.S. studies, women receiving the treatment experienced more blood clots and either more or the same amount of heart disease and strokes than did the women who didn’t get the supplement (SN: 7/27/02, p. 61).

Luckily, not every follow-up study contradicts earlier work. The longest follow-up studies on breast cancer surgery confirmed that the breast-sparing surgery called lumpectomy benefits women just as much as having an entire breast removed (SN: 10/19/02, p. 243).

Yet many of the 2002 scientific findings that we list below challenge earlier results. Mars may not have had a continuously warm, wet past. Neutrinos have mass after all. Diamond isn’t the sturdiest material.

So, what you learned in school years ago–or what you read just last year–doesn’t necessarily correspond to today’s scientific conclusions. To keep current, you’ll want to follow the twists and turns as researchers apply new technologies and carry out larger, longer, and smarter studies. At Science News, now in its 80th year of publication, all hands are devoted to keeping you up-to-date with timely, concise reports.

–Julie Ann Miller, Editor

The following review lists important science stories of 2002 reported in the pages of

Science News. The reference after each item gives the date and the

volume and page number on which the main article appeared (vol. 161 is

January–June; vol. 162 is July–December). An asterisk (*) indicates that the

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Science News of the Year 2002

Anthropology & Archaeology

Biomedicine

Botany & Zoology

Cell & Molecular Biology

Earth Science

Environment & Ecology

Food Science & Nutrition

Mathematics & Computers

Paleobiology

An asterisk (*) indicates that the text of the item is available free. The full text of any article can be obtained by Science News subscribers who have registered and signed in.

Anthropology & Archaeology

People everywhere divvy up food and make other deals based on social concepts of fairness, not individual self-interest, a cross-cultural project found (Feb. 16, 161: 104).
A newly found fossil skull entered an ongoing debate about whether the human ancestor Homo erectus was a single species or several (March 23, 161: 179*).
Investigators reported that the distinctive looks and thinking styles of people and chimpanzees derive from contrasting actions of their similar DNA sequences (April 13, 161: 227).
Excavators of an ancient site in southeastern Mexico stirred controversy with the announcement that they had found examples of the earliest known writing in the Americas (Dec. 7, 162: 355).
An anthropologist recovered the 40,000-year-old skeleton of a Neandertal baby from a French museum, where it had been stored and forgotten for nearly 90 years (Sept. 7, 162: 148).
Scientists unearthed the first chimpanzee archaeological site, which included stone nut-cracking implements (March 30, 161: 195*). Another dig yielded evidence that hard-shelled nuts were a dietary staple of human ancestors living in the Middle East 780,000 years ago (Feb. 23, 161: 117).
A controversial genetic analysis concluded that Homo sapiens evolved by leaving Africa in multiple waves beginning at least 600,000 years ago and then interbreeding with Neandertals and other close relatives (March 9, 161: 149).
Chilean excavations revealed that, starting around 13,000 years ago, people lived at extremely high altitudes during rainy periods, when they could set up hunting camps on the shores of mountain lakes (Oct. 26, 162: 259*).
A nearly toothless fossil jaw found in France reignited scientific debate over whether skeletal remains of physically disabled individuals show that our Stone Age ancestors provided life-saving aid to the ill and infirm (Nov. 23, 162: 328).
Archaeological discoveries indicated that ancient groups in Mexico and Central America believed in a sacred landscape and held key rituals in natural and human-made caves (May 18, 161: 314*).

Astronomy

Setting their sights on the galaxy’s faintest stars, scientists calculated the universe’s age to be between 13 billion and 14 billion years (May 4, 161: 277).
A newly installed camera on the Hubble Space Telescope produced a picture of the distant universe that ranks as the sharpest and most detailed ever recorded (May 4, 161: 278). Other Hubble images demonstrated that the craft’s infrared vision has been restored after 3 years of blindness (June 8, 161: 358).
Observing a tiny galaxy still in the process of being born, astronomers got a rare glimpse of how larger galaxies formed early in the history of the universe (Sept. 14, 162: 164).
New observations of the cosmic microwave background provided additional support for the Big Bang (Sept. 28, 162: 195*). The most detailed snapshots of the infant universe ever recorded are providing additional evidence that a mystery material makes up the bulk of the cosmos’ energy and is accelerating the rate at which the universe expands (Dec. 21&28, 162: 390).
Using new computer models, astronomers explored the birth of the first stars in unprecedented detail (June 8, 161: 362*).
Analyzing data from a mammoth sky survey, astronomers found that there are two distinct families of galaxies, according to stellar mass (Oct. 19, 162: 244).
Astronomers found a star so old and chemically primitive that it carries vestiges of the origin of our galaxy (Nov. 2, 162: 277*).
A vast, invisible halo of hot gas envelops the Milky Way and could be brushing up against our nearest galactic neighbors (Jan. 12, 161: 21).
Researchers uncovered new details about the earliest galaxies and galaxy clusters in the universe (March 30, 161: 196).
New measurements revealed that some of the earliest galaxies in the universe produced winds so powerful and persistent that they profoundly influenced the evolution of future generations of galaxies (April 20, 161: 244).
Astronomers welcomed the discovery of two supermassive black holes in one galaxy (Nov. 30, 162: 339*). Other researchers found the best evidence to date that a supermassive black hole lies at the Milky Way’s core (Nov. 9, 162: 301).
Two teams of astronomers reported that they had confirmed the existence of a new, midsize class of black hole (Sept. 21, 162: 180*).
New evidence supports the notion that gamma-ray bursts, the most violent explosions in the universe, are the primal calling cards of newborn black holes (April 13, 161: 228). A sizable minority of gamma-ray bursts may originate in relatively nearby galaxies (Jan. 19, 161: 37).
A catastrophic outpouring of water–in a volume four times that of Lake Tahoe–may have gushed from fissures near the equator on Mars as recently as 10 million years ago (March 9, 161: 157). Yet contrary to a popular model in which ancient Mars was warm, wet, and hospitable to life, the Red Planet may have been cold and dry for most of its history, with only brief episodes of scalding rain and flash flooding (Dec. 14, 162: 372).
Astronomers obtained the first X-ray image of the Red Planet (Nov. 30, 162: 342).
Astronomers discovered 12 previously unknown stars that lie within a mere 33 light-years of Earth (Feb. 2, 161: 77).
Two titanic storms in Jupiter’s upper atmosphere collided (Feb. 9, 161: 85*).
Extrasolar-planet hunters came up with a landmark finding: a Jupiterlike planet orbiting a sunlike star at a Jupiterlike distance (June 15, 161: 371*).
Images of gaps, rings, arcs, warps, and clumps in disks of dusty debris surrounding nearby stars provided new clues to the nature of planets beyond the solar system (May 4, 161: 280*).
Astronomers measured the mass of a planet outside the solar system (Dec. 7, 162: 357).
Astronomers reported the first evidence that a young star has an orbiting belt of asteroids held in place by a massive, unseen planet (June 22, 161: 388).
A comet split into 19 fragments strung out along a million-kilometer-long chain (Aug. 3, 162: 69).
Planetary scientists have for the first time precisely dated a collision that smashed an asteroid into fragments (July 13, 162: 30).
Astronomers were given two rare opportunities to peer through the atmosphere of Pluto (Sept. 7, 162: 148).
The sharpest visible-light images of the sun ever recorded revealed puzzling new features of sunspots (Nov. 16, 162: 310).
Pointing a ground-based telescope at Jupiter’s moon Io, astronomers reported finding the most powerful volcano ever observed in the solar system (Nov. 23, 162: 326).
Using new computer models, astronomers explored the birth of the first stars in unprecedented detail
(June 8, 161: 362*).

Behavior

Imaging data indicated that the brains of children diagnosed with attention-deficit hyperactivity disorder are slightly smaller than those of their peers without psychiatric disorders (Oct. 12, 162: 227*).
A long-term study found that a genetic variant linked to high concentrations of certain brain chemicals protects abused children from becoming violent and impulsive later in life (Aug. 3, 162: 68). Another study suggested that physical abuse at home tunes a child’s perceptual system to pick up facial signs of anger (June 22, 161: 389).
Two genes involved in transmission of glutamate, a key chemical messenger in the brain, were implicated in the severe mental disorder schizophrenia (Sept. 28, 162: 195).
Researchers presented theoretical alternatives to the influential notion that genetic competition during the Stone Age yielded human brains prewired for specific types of thinking (Sept. 21, 162: 186).
In a 2-year study, bereaved spouses who often talked with others and briefly wrote in diaries about their emotions fared no better psychologically than their tight-lipped, unexpressive counterparts did (March 2, 161: 131*).
A variety of studies explored the nature of social interactions on the Internet, from the factors that make for efficient online corporate work groups to the motivations for joining white supremacist chat rooms (May 4, 161: 282*).
Babies studied between ages 6 and 9 months lost their ability to distinguish individual faces in animal species but started to develop an expertise in discerning human faces (May 18, 161: 307*).
Experiments with a split-brain patient suggested that left-hemisphere structures contribute to the conscious understanding of oneself (Aug. 24, 162: 118*).
A reanalysis of brain-imaging data linked conscious visual experience to activity throughout the brain, challenging the popular view that only a few specific brain areas coordinate this mental state (Oct. 19, 162: 251).
Male monkeys’ social position influenced their brains’ chemical susceptibility to cocaine’s addictive pull (Jan. 26, 161: 53*).
In a surprising finding with implications for understanding nicotine addiction, cigarette smokers monitored for 1 week reported feeling no different just before they lit up than at other times when they weren’t smoking (Nov. 30, 162: 340).
A controversial report concluded that far fewer people suffer from mental disorders requiring treatment than earlier surveys had indicated (Feb. 16, 161: 102).
Scientists found that a brief daytime nap may block or even reverse learning declines that occur during extended practice of a perceptual task (June 1, 161: 341*).
A substantial and largely unnoticed minority of war reporters and photographers told investigators that they had developed symptoms of a severe stress disorder as a result of their jobs (Sept. 14, 162: 165).

Biomedicine

Spurred by threats of bioterrorism, researchers unveiled the anthrax bacterium’s genome (May 18, 161: 317*) and reported possible ways of blocking its deadly effects (Aug. 24, 162: 115*).
In women, vaccines stopped human papillomavirus, the cause of cervical cancer (Nov. 23, 162: 323); 10 common bacteria that cause bladder infections (Jan. 5, 161: 5); and the virus that causes genital herpes (Dec. 21&28, 162: 399). Another vaccine protected kidney-dialysis patients from common blood infections (Feb. 16, 161: 99). In the lab, a malaria vaccine showed promise (Aug. 17, 162: 99), and a vaccine fashioned from pieces of the viruses that cause dengue fever and West Nile fever protected mice against West Nile infections (March 16, 161: 164).
Several studies indicated that the health risks associated with estrogen therapy for postmenopausal women outweigh its benefits (July 27, 162: 61*).
Among women who harbor mutations in the BRCA genes, ovary removal reduced the risk of ovarian, peritoneal, and breast cancers (May 25, 161: 323*). Three new drugs stopped acute myeloid leukemia in mice, suggesting new treatments against this deadly blood cancer in people (June 15, 161: 371*).
Researchers gathered evidence that inflammation precedes and predicts diabetes (Aug. 31, 162: 136*) and showed that people who died suddenly of heart attacks had an abundance of C-reactive protein, an indicator of inflammation, in their blood (April 20, 161: 244).
A pharmaceutical company halted tests of vaccine against Alzheimer’s (Feb. 16, 161: 109), but a drug showed it can interfere with deposits of amyloid, like those in the brains of people with Alzheimer’s disease (May 18, 161: 307).
Government scientists found that stockpiled smallpox vaccine doses can be diluted to one-tenth their original concentration and still be effective (April 13, 161: 238). And researchers calculated that vaccinating an entire city in response to a smallpox attack would save thousands more lives than would quarantining infected people and vaccinating their contacts (July 13, 162: 21).
New controversy about old data had physicians, women, and policy analysts struggling to decide whether mammography reduces deaths from breast cancer (April 27, 161: 264).
Tailoring prescriptions according to a person’s genes may help reduce side effects and enable doctors to deliver more personalized medicine (Sept. 14, 162: 171*). Another approach to individualizing therapy is to monitor molecular and cellular changes in cancer cells as people respond to cancer therapies (March 2, 161: 139).
A hormone called erythropoietin, long used to treat anemia, also seems to protect against nerve damage and holds promise as a new therapy for stroke and spinal cord injury (Nov. 9, 162: 296).
The discovery of an enzyme that scientists are calling cyclooxygenase-3, which is disabled by acetaminophen, might explain why this over-the-counter drug can stop pain and fever but not inflammation (Sept. 21, 162: 180). Another study showed that women who take acetaminophen or ibuprofen for headaches boost their chances of developing high blood pressure (Nov. 2, 162: 278).
New studies suggested that a natural alerting of immune cells to foreign invaders could explain why infection with HIV progresses to AIDS more quickly in some people than in others (June 8, 161: 360).
A drug fashioned from a mouse antibody halted the progression of diabetes in children and young adults newly diagnosed with the disease (June 1, 161: 339*).
Icing down patients whose hearts had stopped boosted their chances of survival and prevent brain damage (Feb. 23, 161: 115).
Viruses that destroy bacteria protected mice from antibiotic-resistant bacteria (Jan. 12, 161: 23).
Research showed that drugs being tested against cancer because they thwart new blood vessel growth might also be a treatment for obesity (Aug. 3, 162: 67*).
A decade-long study bolstered the link between the Epstein-Barr virus and multiple sclerosis by showing that the common infection is more active in people who later develop the nerve disease (Jan. 5, 161: 4).
Relatively few of the New York firefighters involved in rescue and recovery after the terrorist attack
on Sept. 11, 2001 developed chronic coughs and respiratory problems, but among those who did, the problems seem unusually severe (Oct. 5, 162: 222).
A study showed that Parkinson’s disease damages nerve endings in the heart, kidneys, and thyroid gland, which may explain dizziness and fainting in people with this neuromuscular disease (May 11, 161: 293). In a lab test, alcohol made some pain-generating nerves trigger more easily than normal (May 11, 161: 294).
Ten years after the discovery of the gene that, when mutated, causes cystic fibrosis, researchers still struggled to understand why deadly lung infections are so common in people with the disease (Jan. 26, 161: 59).
A new compound mimicked the effects of an extremely low-calorie diet and lowered the incidence of diabetes and heart disease in monkeys (Feb. 2, 161: 77). Severely restricting their calorie consumption kept some dogs living about 22 months longer than nondieting canines (May 11, 161: 291).
Sleeping 8 to 10 hours a night doesn’t necessarily translate into a longer life (March 16, 161: 173). However, new evidence suggested that chronic lack of sleep might be as damaging as poor nutrition and physical inactivity in the development of chronic illnesses such as obesity, diabetes, and cardiovascular disease (Sept. 7, 162: 152*).
To design better drugs and medical care, researchers are increasingly turning to computer simulations of patients and treatments (Dec. 14, 162: 378*).
Men who maintained grueling mountain bicycling programs were apt to have lower sperm counts and more testicular damage than nonbikers were (Dec. 7, 162: 355*).
Researchers found genes linked to prostate cancer (Jan. 26, 161: 51*; Sept. 28, 162: 205), aggressive breast cancers (Feb. 2, 161: 68; April 27, 161: 259), and lung cancer (April 20, 161: 254). They also found a mutation that can predispose women to uterine growths called fibroids (March 9, 161: 149).
Research on probiotic bacteria-living microbes that confer health benefits when intentionally introduced into the body-offered growing medical promise (Feb. 2, 161: 72*).
A kiss can trigger allergic reactions to molecules carried on a person’s lips (July 20, 162: 40*).
Scientists identified a new class of compounds that stops herpes simplex virus from replicating (April 13, 161: 227*).
Nicotine impairs a molecule that’s necessary for arousing people and other animals from sleep, an effect that could account for the heightened risk of sudden infant death syndrome in babies born to women who smoked during pregnancy (Sept. 14, 162: 163).
Researchers found that babies who tolerate a salty flavor have higher blood pressure on average than do their less tolerant counterparts (Aug. 17, 162: 101).
New images revealed that the bacterium that causes leprosy directly attacks the fatty sheath that coats healthy nerve fibers, leaving them irreversibly damaged (June 8, 161: 365).

Botany & Zoology

A wildlife brain ailment, once limited to a small part of the West and some game farms, turned up in wild deer in new areas, such as Wisconsin (Nov. 30, 162: 346*).
The first video of the deep-ocean dwellers called whipnose anglerfish showed that scientists have had it wrong and the fish actually swim “upside down” (Oct. 26, 162: 262).
Researchers found that a walking stick insect may be evolving into two species by adapting to different environments (June 1, 161: 350), and reef corals that spawn in great, churning, multispecies soups may be maintaining diversity because hybrids are nearly sterile (June 15, 161: 374).
An unusual sex attractant–male bile acid–turned up in an analysis of sea lampreys, and it may inspire new ways to defend the Great Lakes against this invasive species (April 6, 161: 213).
Microscopy revealed that the sperm of wood mice hook together by the thousands to form high-speed teams racing toward an egg, even though only one of each pack can win the prize (July 13, 162: 20).
A budgerigar’s head literally fluoresces, and both males and females prefer to court partners with a glow, a study found (Jan. 19, 161: 40).
The largest ant supercolony yet found stretched in a network of cooperating nests from Italy to the Atlantic (April 20, 161: 245).
Scientists pinned down the molecular basis of the gecko’s prowess at scampering up polished walls and hanging from ceilings (Aug. 31, 162: 133).
A mild-mannered reed native to the United States was found innocent; it was being blamed for the environmental damage caused by an evil twin from abroad (Feb. 23, 161: 118).
A microbe related to the one that caused the Irish potato famine was tentatively identified as the long-sought culprit killing majestic beech trees in the northeastern United States (Aug. 3, 162: 70).

Cell & Molecular Biology

Biologists deciphered the DNA sequences of a key malaria-causing parasite and of the mosquito that usually carries it, findings that suggest new ways to combat the deadly disease (Oct. 5, 162: 211*).
The stomach makes a hormone called ghrelin that, in the brain, triggers hunger. Dieting, gastric-bypass surgery, and genetic mutations appeared to disturb the hormone’s production (Feb. 16, 161: 107*, June 8, 366; July 6, 162: 14).
Two research groups independently described the entire genetic sequence of rice, a first for a crop plant (April 6, 161: 211*).
A national advisory panel recommended outlawing cloning aimed at creating a child but suggested allowing medical experiments with cloned human cells (Jan. 26, 161: 52).
Generating controversy over the potential of similar work in people, scientists showed that stem cells derived from cloned mouse and cow embryos can cure some animal diseases and create organs such as kidneys (March 16, 161: 163*, June 8, 356*). Offering an alternative source for similar human cells, researchers showed that bone marrow from adults contains cells that can mature into many specialized types (June 22, 161: 390).
Scientists obtained long-lived stem cells from monkey eggs stimulated to develop without being fertilized by sperm (Feb. 9, 161: 94).
Stoking bioterrorism fears, scientists proved they could build the poliovirus from scratch, using the widely known genetic sequence and available chemicals (July 13, 162: 22).
An unexpectedly large number of genes encode RNA strands instead of proteins (Jan. 12, 161: 24*). Scientists started using short RNA strands to inhibit viruses and cancer growth (Aug. 10, 162: 93, Sept. 21, 189).
A microbe plucked from a volcanically heated ocean bed has the smallest number of genes of any living organism studied (May 4, 161: 275).
Two common general anesthetics produce their sedative effects by triggering the brain’s natural sleep circuits (Aug. 31, 162: 132*).
Parasites infect male mammals more often than females, possibly contributing to the tendency for male mammals to die earlier than females (Sept. 21, 162: 182).
Biologists identified the enzyme in mammalian sperm that triggers development of a fertilized egg (Sept. 21, 162: 189) and found that sperm contain an unexpected payload of RNA (Oct. 5, 162: 216).
Variations in a gene called klotho may influence the length of a person’s life (Jan. 19, 161: 36*).
A study in worms suggested that during aging, the nervous system stays intact but muscles degenerate (Oct. 26, 162: 260).

Chemistry

Researchers experimented with more sustainable ways to generate hydrogen, which burns cleanly but is typically made from fossil fuel (Oct. 12, 162: 235*).
Surgical sutures made from a new biodegradable material tie themselves into a knot and tighten as the material warms to body temperature (April 27, 161: 262).
Scientists explored nanomaterials’ possible negative consequences in the human body and the environment (March 30, 161: 200*).
A new material could make rechargeable lithium-ion batteries smaller, cheaper, and safer (Sept. 28, 162: 196*).
Some of the new two-alloy European Union coins release large amounts of nickel, a common skin irritant (Sept. 14, 162: 163*).
Researchers transformed viruses into potential building blocks for electronic circuits and tools for biomedical therapies (Feb. 2, 161: 68).
A single molecule performed mechanical work-pulling and releasing a cantilever tip-when exposed to light (May 11, 161: 292).
A new analysis revealed that the production of a single 2-gram microchip requires nearly 2 kilograms of chemicals and fossil fuels (Nov. 16, 162: 309).
Two studies of inks and paper renewed controversy about the authenticity of a map that some scholars claim is the first depiction of North America (Aug. 17, 162: 109).
A new technique made artificial receptors that differentiate among molecules that are similar to each other (July 27, 162: 53).
Two experiments simulating the environment of interstellar space produced amino acids, the building blocks of proteins (March 30, 161: 195*).
A novel modification of polymer membranes gave researchers a means to tune certain filters to be more selective yet faster (April 20, 161: 245). Other experiments suggested that a new membrane would make it easier to separate mixtures of the right-hand and left-hand versions of drug molecules (June 22, 161: 388). A recently devised, metal-laced organic solid proved that it can act as a sieve for nanosize molecules (Oct. 5, 162: 213).

Earth Science

Weather data gathered during the 3-day shutdown of commercial aviation within the United States after Sept. 11, 2001, suggest that the contrails from high-flying jets have a significant effect on Earth’s climate (May 11, 161: 291*).
Early in the year, scientists analyzed rainfall patterns in the Indian Ocean and predicted the late-summer return of El Nio, the worldwide weather maker marked by sea-surface warming in the tropical Pacific (March 2, 161: 142). In July, NOAA researchers confirmed the phenomenon’s arrival (Aug. 17, 162: 110).
A fresh look at old experimental data suggests that water droplets in clouds freeze from their surface inward, a finding that would overturn a theory in place for more than 6 decades (Nov. 30, 162: 340*).
Seafloor sediments suggest that the plankton-nourishing iron that’s in surface waters surrounding Antarctica comes from upwelling deepwater currents, not from dust blowing off the continents (Jan. 5, 161: 6).
A Rhode Island-size section of the Antarctic’s Larsen B ice shelf splintered into thousands of icebergs in a mere 5-week period during the area’s warmest summer on record (March 30, 161: 197).
An analysis of trace elements in meteorites suggested that most of the heavenly objects that rained hell on the inner solar system about 3.9 billion years ago were asteroids, not comets (March 9, 161: 147).
Sediments laid down on Earth about 3.47 billion years ago contain remnants of what may have been an extraterrestrial object large enough to disperse collision debris over the entire planet (Aug. 24, 162: 115).
A new model found that the bull’s-eye in Tornado Alley lies over southeastern Oklahoma, where any particular spot can expect to get damaged once every 4,000 years (May 11, 161: 296*). As of Aug. 1, barely half the usual number of tornadoes had struck the lower 48 U.S. states (Aug. 24, 162: 125).
Analysis of lab-made minerals suggested that the zone of rocks just outside Earth’s core could hold enough water to fill the oceans five times (March 30, 161: 205).
Super-concentrated salt water at the bottom of Antarctica’s Lake Vida has been sealed off from the world for at least 2,800 years and may support life (Dec. 21&28, 162: 387).
Scientists can map the size and distribution of ice particles in a cirrus cloud by combining simultaneous observations from satellites and ground-based instruments (June 1, 161: 342).
Rose Garden, one of the first undersea hydrothermal vents to be discovered nearly 25 years ago near the Galpagos Islands, may have been covered by a recent volcanic eruption (June 15, 161: 382).
Mangled microfossils may become a new diagnostic tool for identifying the sites of ancient, hidden extraterrestrial-object impacts (June 15, 161: 382).
Scientists refined a technique for calculating the probability of encountering stinging jellyfish in Chesapeake Bay (July 27, 162: 52).
Data from Arabian Sea sediments suggest that Asian monsoons have been intensifying over the past 400 years, and scientists predict that these storms are slated to get worse (July 27, 162: 54*).
Defense Department mapmakers and NASA scientists are assembling billions of radar measurements made from the space shuttle Endeavour to produce what will be the world’s best topographic map (Feb. 23, 161: 126).

Environment & Ecology

At water concentrations found in the environment, the weed killer atrazine stripped male frogs of their masculinity, suggesting that the chemical is partly responsible for global amphibian declines (April 20, 161: 243*; Nov. 2, 162: 275*).
Several dozen organic contaminants were quantified in U.S. streams, and the chemicals’ combined effects may be killing aquatic organisms (March 23, 161: 181).
Pfiesteria microbes, implicated in fish kills and human illness along the mid-Atlantic U.S. coast, turned up in Norway (Jan. 19, 161: 39). Another study suggested that some types of Pfiesteria don’t produce a toxin but kill by eating holes in a fish’s skin (Aug. 10, 162: 84).
Chemical analyses of seawater provided the first direct evidence that the ocean may be a significant source of atmospheric gases–alkyl nitrates–that scientists had assumed trace mainly to industrial activity (Aug. 17, 162: 102).
Farm-field runoff containing hormones excreted by steroid-treated livestock appeared capable of harming aquatic life (Jan. 5, 161: 10*).
Researchers found reason to suspect that artificial lighting at night disrupts the physiology and behavior of nocturnal animals (April 20, 161: 248*).
A study of adolescents suggested that widespread environmental pollutants, such as polychlorinated biphenyls and dioxins, might be delaying young people’s sexual development (July 6, 162: 3).
Tests on sunflowers showed that a lab-engineered gene from a crop plant, if introduced into its wild relative, can give the native plant a survival edge over other wild plants (Aug. 17, 162: 99*).
New research and policy developments aimed to curb the practice of killing sharks solely for their fins, an Asian delicacy (Oct. 12, 162: 232*).
Researchers found that antibiotics excreted by people and animals have the potential to poison plants and end up in food (June 29, 161: 406*).
Scientists experimented with sprays of dirt particles to kill toxic algae in seawater (Nov. 30, 162: 344).
A study discovered that fallen leaves that collect in stagnant water can release toxic mercury, which can eventually accumulate in fish far downstream (March 9, 161: 148).
Minuscule amounts of over-the-counter weed killers impaired reproduction in mice (Oct. 12, 162: 228).
Scientists found indications that dioxin, a hormonelike pollutant, can trigger breast cancer in heavily exposed women (Aug. 3, 162: 77).
Trace amounts of human-excreted drugs in waterways appeared to work together to deform and kill native microscopic organisms (Aug. 17, 162: 101).
Living with a smoker at least doubled a cat’s risk of developing the feline analog of the cancer non-Hodgkin’s lymphoma (Aug. 24, 162: 125).
Algae fight over nutrients, and one Swedish combatant under frozen lakes apparently prevails by poisoning its adversaries (Jan. 26, 161: 61).
Atmospheric scientists learned that the Mediterranean Sea is a crossroads for pollution-laden air currents from Europe, Asia, and North America (Oct. 26, 162: 261).
Set alight by wildfires, thick beds of decaying tropical-plant matter can spew massive amounts of carbon, which researchers calculated could rival global emissions from fossil fuels (Nov. 9, 162: 291*).

Food Science & Nutrition

Vegetarians’ low intake of vitamin B12 may cause an overabundance of the amino acid homocysteine and thus increase their risk of heart disease (Feb. 16, 161: 100).
Even a little supplemental folate during a mother’s pregnancy appeared to reduce the risk that her child will develop acute lymphoblastic leukemia (Jan. 5, 161: 8). Dietary folate also helped avert colon cancer in women (April 20, 161: 253).
Diets rich in whole rather than processed grains may help protect overweight people from diabetes and heart disease by improving their management of blood sugar concentrations (May 18, 161: 308).
A diet containing fish oil that’s rich in omega-3 fatty acid cut inflammation of the colon in rats, so it might benefit people with colitis (Jan. 26, 161: 53).
People fighting high blood pressure benefited from drinking cocoa (March 2, 161: 142) and red wine (Jan. 5, 161: 8), thanks to the actions of plant polyphenols, which both beverages contain in abundance.
Lycopene, which makes tomatoes red and in people’s diets might help guard against prostate cancer, was found more abundant in watermelons than in tomatoes (July 13, 162: 29).
Honey can contain traces of potent liver-damaging compounds produced naturally by many flowering plants (May 18, 161: 317).
Large doses of the estrogenlike hormones in soybeans and soy-based infant formulas weakened the immune systems of mice (May 25, 161: 325*).
Although cooking sweet corn reduced its concentration of the antioxidant vitamin C, the process increases corn’s overall disease-fighting antioxidant activity (Aug. 31, 162: 141).
Moderate alcohol consumption appeared to reduced a drinker’s risk of developing Alzheimer’s disease and other forms of age-related dementia (Feb. 2, 161: 67*).
A chemical abundant in broccoli killed ulcer-causing Helicobacter pylori bacteria in the laboratory and inhibited stomach cancer in mice (June 1, 161: 340).
Garlic supplements interfered with one of the drugs people take to fight an HIV infection (Jan. 5, 161: 8).

Mathematics & Computers

A novel approach for identifying prime numbers provided a long-sought improvement in the theoretical efficiency of algorithms for that task (Oct. 26, 162: 266*).
A mathematician proved Catalan’s conjecture, a venerable problem in number theory concerning relationships among powers of whole numbers (May 25, 161: 324).
Analyzing a variant of the familiar game of 20 questions offered insights into Internet communication (April 6, 161: 216*).
Researchers developed speedy automated methods, based on differential equations, to repair or modify digital images (May 11, 161: 299*).
Analyses of sliding-block puzzles led to a novel theoretical model of computer logic (Aug. 17, 162: 106*).
For the first time, a simple, molecule-based quantum computer carried out Shor’s algorithm for factoring a whole number (Jan. 12, 161: 31).
In a classified U.S.-government experiment, what was then the world’s fastest computer simulated a thermonuclear blast in three dimensions (March 23, 161: 189).
A government report estimated that software errors in industrial computer programs cost the United States about
$60 billion per year (July 20, 162: 45).
Researchers used a mathematical model of peer-influenced behavior to explain unexpected patterns in financial data and bird populations (Aug. 24, 162: 116).
Researchers introduced a new method for gaze-operated, hands-free text entry that’s faster and more accurate than using an on-screen keyboard (Aug. 31, 162: 141).

Paleobiology

Fossil remains of a creature that had rodentlike incisors and a hefty overbite provided the first distinct dental evidence for plant-eating habits among theropod dinosaurs (Sept. 21, 162: 179*).
A biomechanical analysis of Tyrannosaurus rex hinted that the creature ran only slowly, if at all (March 2, 161: 131*).
Fossil leaves unearthed in central Colorado suggested that the region contained one of the world’s first tropical rain forests just 1.4 million years after the demise of the dinosaurs (June 29, 161: 403*).
A fossil originally misidentified as an ancient fish turned out to be the nearly intact remains of a four-limbed creature that lived during a period that left few fossils of land animals (July 6, 162: 5).
Fossils unearthed in Brazil strengthened the notion that some species of ancient flying reptiles swooped low over the water’s surface and snapped up fish (July 20, 162: 35).
Scientists found the birdlike footprints of a yet undiscovered creature in rocks more than 60 million years older than Archaeopteryx, the first bird to leave fossil remains (July 27, 162: 62).
Paleontologists unearthed fossils of a tiny, duck-billed crocodile that boasted a smile like no other: The animal had no front teeth (March 2, 161: 142).
Newly discovered fossils of aquatic reptiles known as mosasaurs suggested that the creatures gave birth in midocean rather than in near-shore sanctuaries, as previously suspected (Oct. 26, 162: 270).
Scientists said that a sediment-filled, bathtub-shape depression at one of North America’s largest dinosaur trackway sites is the first recognized evidence of dinosaur urination (Oct. 26, 162: 270).
Leonardo, a mummified dinosaur unearthed in Montana, gave scientists a rare peek at what the creature’s muscles, beak, skin, and other soft tissues may have looked like (Oct. 19, 162: 243*).

Physics

Observations of ghostly neutrinos from the sun and from nuclear-power reactors suggested that all neutrino types violate the prevailing theory of particle physics by frequently changing their identities (May 11, 161: 301; Dec. 14, 162: 371*).
Scientists demonstrated transistor action by a single atom (Aug. 10, 162: 88*).
A deviation from theoretical predictions of the magnetic strengths of subatomic muons hinted at an undiscovered realm of elementary particles (Sept. 7, 162: 158).
Electron bombardment of neutrons revealed that the nominally neutral particles contain regions of positive and negative charge (April 27, 161: 262).
Exotic cousins of protons and neutrons known as doubly charmed baryons made their laboratory debut (July 6, 162: 14).
Two prominent physicists lost their jobs following allegations that they had fabricated data in landmark experiments (July 20, 162: 37, Oct. 5, 214).
Theorists proposed that ultradense specks of matter–microscopic black holes–might fleetingly appear in Earth’s atmosphere and in a powerful particle accelerator soon to be built (March 23, 161: 187*).
In a controversial claim, researchers presented evidence of nuclear fusion in bubbles imploding in a liquid bombarded by sound waves (March 9, 161: 147*). Other scientists reported that a cooling process in such bubbles makes fusion unlikely (Aug. 24, 162: 125).
Researchers unveiled a novel microchip that’s a laser that emits a band of infrared light rather than the single, pure wavelength of a typical laser (Feb. 23, 161: 115*).
In ultrahigh-compression experiments, the rare metal osmium outperformed diamond for sturdiness (April 6, 161: 211*). Meanwhile, scientists continued to improve synthetic diamonds (Sept. 14, 162: 165*).

Technology

For cell phones and other portable electronics, researchers field-tested prototypes of tiny, refillable fuel cells expected to last much longer than today’s batteries (Sept. 7, 162: 155*).
Chemists synthesized new gelatinous and rubbery polymers that may serve as superior dressings for wounds (July 13, 162: 20) and as scaffolds for artificial organs and tissues (May 25, 161: 323, June 29, 408; Aug. 10, 162: 93).
A compact cooler incorporating a permanent magnet showed that it could give rise to household refrigerators and air conditioners that depend on magnetism instead of volatile liquids (Jan. 5, 161: 4*).
Researchers packed thousands of microscopic pipes and chambers onto fluid-manipulating microchips of unprecedented power (Sept. 28, 162: 198).
Novel microstructures of crisscrossed tungsten rods filtered various wavelengths of radiated heat–a talent that someday might boost the efficiency of lightbulbs (May 25, 161: 334).
An electronic display capped by a transparent polymer membrane applied as a liquid and then solidified may be a step toward paint-on displays for walls and fabrics (June 1, 161: 349).
Scientists unveiled new building blocks for ultrasmall electronic circuits including striped nanowires, embossed silicon, and welded nanotubes (Feb. 9, 161: 83*, June 22, 390*; Oct. 5, 162: 222) and a novel magnetic microcircuit (June 15, 161: 373).

Science News of the Year 2001