# Science News of the Year 2000

Years ago, fresh out of a statistics course, I made some friends laugh by insisting that an election shouldn’t be considered valid unless the difference between the vote counts is statistically significant. I was viewing an election as an experiment with the hypothesis that more of the voters wanted candidate A than candidate B. I didn’t pursue the idea because a vote count seemed to me to be a fixed result. How could you measure variability without holding the election repeatedly day after day? Was I naive! I knew nothing then of chad or dimpled ballots, and I hadn’t considered what it would really be like to count millions of ballots.

Nevertheless, when statisticians attracted the spotlight in the presidential election this year, I felt vindicated. While some calculated that many people had made mistakes in marking a butterfly ballot and others estimated how various recounts might change the tallies, a few made just my point. For example, mathematician John Allen Paulos of Temple University in Philadelphia figured that the difference between the Florida vote totals of Al Gore and George W. Bush is no more than that expected between the number of heads and tails of a coin tossed 6 million times. So, he’d say the Florida vote could best, statistically speaking, be considered a tie.

Thankfully, nothing as significant as the nation’s leadership rests on the outcome of a single scientific experiment. Researchers have the option of concluding that they didn’t get a clear-cut answer to the question posed, and scientists often apply statistical tests to guide that judgment.

Because readers of Science News want information that they can count on, we try to report only results that meet accepted confidence standards. This can be difficult because some scientists, in their enthusiasm, gloss over uncertainties. Only occasionally do we deliberately report a result that falls short of statistical significance, and then we point out its tentative nature. For example, in a recent report on the long-term health of calorie-restricted monkeys (SN: 11/25/00, p. 341), we included a preliminary finding. We considered the topic to be of great interest, the results of such studies slow in coming, and our readers unlikely, without more solid evidence, to do anything more drastic than cutting back on desserts. Perhaps such results can best be regarded in the same light as a voter poll held months before the election.

—Julie Ann Miller

 Anthropology & Archaeology Astronomy Behavior Biology Biomedicine Botany & Zoology Chemistry Earth Science Environment & Ecology Food Science Mathematics & Computers Paleobiology Physics Technology

This review lists important science stories of 2000 reported in the pages of Science News. The reference after each item gives the date, volume, and page number on which the main article on the subject appeared (vol. 157 is January-June; vol. 158 is July-December). An asterisk indicates that the text of the item is available free on Science News Online (https://www.sciencenews.org). Full text of any article can be obtained for \$2.50 from ProQuest (http://pqasb.pqarchiver.com/sciencenews).

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Anthropology & Archaeology

• A pair of 1.7-million-year-old fossil skulls discovered in Asia offered a glimpse of perhaps the first species of human ancestors to exit Africa (May 13, 157: 308).
• Evidence in a sand dune suggested that people inhabited southeastern Virginia at least 15,000 years ago (April 15, 157: 244*).
• Chinese finds indicated that Stone Age folk made hand axes across a surprisingly broad swath of Asia (March 4, 157: 148*).
• Controversial new clues to possible cannibalism emerged in the prehistoric U.S. Southwest (September 9, 158: 164*).
• An analysis of the Y chromosome in modern men enlivened debate over human evolution (November 4, 158: 295), as did reports on DNA specimens retrieved from Neandertal fossils (April 1, 157: 213*; July 8, 158: 21).
• Researchers contended that many Stone Age statuettes of women found across Europe depict previously unrecognized items of clothing (October 21, 158: 261).
• Mounting evidence portrayed whales and dolphins as cultural creatures that transmit knowledge socially (October 28, 158: 284*).
• New insights into the genetics of body development raised doubts about the statistical method that many anthropologists use to create evolutionary trees (November 25, 158: 346).
• A cross-cultural investigation concluded that the child-rearing practices in some modern forager groups perpetuate trust and sharing (July 1, 158: 8).
• Excavation of a 125,000-year-old site on the African coast of the Red Sea markedly pushed back the date of the earliest seaside settlement (May 6, 157: 292).
• Scientists observed greetings among wild baboons and other clues to the mental lives of these primates (April 29, 157: 280).

Astronomy

• In some of the coldest regions on Mars, water appears to have recently gushed from just beneath the surface (July 1, 158: 5*). Images suggest that parts of Mars were once lands of lakes and reveal places to look for evidence of life (December 9, 158: 372*).
• NASA’s two most recent missions to Mars failed because they were underfunded, managed by inexperienced people, and insufficiently tested, a panel found (April 1, 157: 215). Revamping its Mars program, NASA announced it would delay by nearly a decade plans to bring back material from the Red Planet (November 11, 158: 310).
• A galaxy map revealed the largest structures in the cosmos (August 12, 158: 104).
• Two new X-ray observatories opened a window on the most energetic cosmic events (October 21, 158: 266*), while astronomers progressed in designing an X-ray mission that would image coronas of nearby stars and black holes (November 4, 158: 292).
• Supermassive black holes at galaxy cores proved far more numerous than visible-light surveys had indicated (January 22, 157: 53*).
• New evidence supported the notion that Jupiter’s moon Europa contains an ocean beneath its icy surface, and a scientist proposed a novel way for Europa to have obtained the energy required to sustain life within that ocean (January 29, 157: 70). A combination of images, spectra, and magnetic field measurements suggested that another Jovian moon, Ganymede, may also have had and may still harbor an ocean (December 23, 158: 404).
• Preliminary tests supported the notion that the expansion of the universe is accelerating (February 12, 157: 106*).
• On Valentine’s Day, the NEAR spacecraft cozied up to the asteroid 433 Eros, becoming the first craft to orbit a tiny body (February 19, 157: 118). NEAR found evidence that the rock dates from the birth of the solar system (June 10, 157: 375) and took the sharpest images yet of an asteroid (November 4, 158: 293).
• Evidence grew that life’s evolutionary explosion on Earth some 540 million years ago occurred around the time that cosmic debris began pummeling our planet at an increasing rate (March 11, 157: 165*). New research also suggested that a swarm of debris bombarded the moon, and likely Earth, some 3.9 billion years ago, about the time life may have debuted on our planet (December 2, 158: 357*).
• Scientists isolated carbon spheres–and perhaps trapped extraterrestrial gas–from meteorites (March 25, 157: 196*).
• A meteorite that fell in the Yukon may date from the solar system’s birth (April 8, 157: 235).
• Astronomers found evidence of extrasolar planets similar in size to those of the solar system (April 1, 157: 220) and the nearest known extrasolar planet (August 5, 158: 84*). For the first time, they obtained images of as many as 18 objects that, based on their mass alone, could qualify as extrasolar planets (October 7, 158: 228*). A controversial study claimed that nearly half the objects reported to be extrasolar planets are merely lightweight stars or star wannabes known as brown dwarfs (October 28, 158: 277*).
• Spacecraft data suggested that otherwise invisible comets could be detected by searches for their tails (April 8, 157: 228*).
• A balloon-borne experiment found that the cosmos is perfectly flat (April 29, 157: 276*).
• Half of the universe’s hydrogen gas, which hasn’t been accounted for, may reside in relatively nearby reaches of intergalactic space (May 13, 157: 310*).
• Astronomers discovered the most distant galaxy so far detected (May 27, 157: 340).
• Researchers developed detailed maps of the distribution of dark matter, the invisible material believed to make up 90 percent of the universe’s mass (May 20, 157: 332).
• Galaxies are surrounded by vast halos of dark matter that may extend at least 1.5 million light-years from their centers (January 15, 157: 36*).
• Physicists duked it out over the existence of WIMPs, elementary particles that could solve a mystery about the universe’s dark matter and help unify the four fundamental forces of nature (February 26, 157: 131).
• Scientists made progress in understanding the origin of solar storms, predicting when and how they will erupt and estimating when they might strike Earth (March 18, 157: 183; April 15, 245; June 24, 404*; September 30, 158: 214).
• A simple sugar was spotted in interstellar space for the first time (June 24, 157: 405).
• Earth’s home galaxy indulged in cannibalism to assemble its so-called visible halo, three studies found (April 22, 157: 261).
• Telescope images of what may be a close-up view of galaxy formation suggested that some streams of gas and dust that are ripped out of large galaxies can form into galaxies of their own (March 4, 157: 151).
• Astronomers may finally have evidence that a spinning object drags space-time along with it (September 2, 158: 150).
• A communications problem was revealed that could prevent the Huygens probe from relaying all its data when it parachutes through the atmosphere of Saturn’s largest moon, Titan, in 2004 (October 21, 158: 262; November 4, 298).

Behavior

• Eye-opening evidence suggested that sleep contributes to certain types of memory formation (July 22, 158: 55; December 2, 358). Other studies examined sleep deprivation’s disturbing effects on the brain (February 12, 157: 103*) and its widespread occurrence among children by the time they reach the sixth grade (May 20, 157: 324*).
• Psychologists conducted a series of studies indicating that East Asian and Western societies foster contrasting mental approaches to reasoning (January 22, 157: 56).
• A survey of public elementary schools in parts of North Carolina found that more than half of those children receiving stimulant medication don’t exhibit the attention-deficit hyperactivity disorder for which physicians prescribe the drugs (July 29, 158: 69*).
• An analysis of babies’ babbling yielded insights into the biomechanics of talking and possibly the nature of prehistoric languages (May 27, 157: 344*).
• In a laboratory experiment, monkeys exhibited signs of perceiving simple melodies much as humans do (September 16, 158: 180).
• A controversial national survey warned of growing social isolation among frequent Internet users (February 26, 157: 135*).
• Review of a Food and Drug Administration database suggested that placebo pills given to depressed people work well enough to dispel ethical concerns about using placebos in studies of antidepressants (April 29, 157: 278*).
• Scientists explored the social roots and psychological aftermath of violent conflicts in many parts of the world (August 5, 158: 88*).
• New evidence strengthened the theory that some families carry a genetic susceptibility to obsessive-compulsive disorder and tic disorders that gets triggered by childhood strep infection (September 2, 158: 151).
• Researchers explored family and psychological forces that influence the mood swings of bipolar disorder (April 8, 157: 232*).
• Fundamental aspects of hearing and vision separately influence children’s ability to read, so investigators suggested that certain types of perceptual training may be useful in reading instruction (March 18, 157: 180*).
• A large sample of young adults tracked since childhood in New Zealand yielded evidence of a link between violent behavior and three mental illnesses: alcohol and marijuana dependence and a condition characterized by a range of psychotic experiences (October 28, 158: 279).

Biology

• Two rival groups, one public and one private, announced that each has read most of the 3 billion or so DNA subunits that spell out the human genome (July 1, 158: 4*).
• Drugs that defuse so-called free radicals lengthen a worm’s life span by more than 50 percent (October 7, 158: 238), and a gene mutation doubles it (December 16, 158: 391).
• Research on stem cells–immature cells that can grow indefinitely and mature into various cell types–exploded. Stem cells may treat damaged corneas (July 15, 158: 36), brain disorders (July 22, 158: 63), and spinal injuries (January 1, 157: 6). Stem cells in bone marrow can form liver cells (July 1, 158: 7) or brain cells (July 22, 158: 55). Human skin and scalp tissue may also provide a source of brain stem cells (December 2, 158: 360), and the brain’s stem cells can replace damaged nerve cells with new ones (July 22, 158: 63).
• A biotech company announced the first cloning of pigs (March 25, 157: 197), and biologists suggested that cloned animals live longer than normal (May 6, 157: 279).
• To help preserve biodiversity, negotiators from 130 nations crafted rules of conduct for international trade in living, genetically engineered organisms (February 5, 157: 84).
• Scientists identified a protein in taste buds that recognizes monosodium glutamate (January 29, 157: 68) and proteins that work as taste receptors for bitterness (March 25, 157: 196*).
• In work that may lead to vaccines, biologists sequenced the genes of two strains of a bacterium that causes meningitis (February 19, 157: 116*). They also deciphered complete genomes of bacteria responsible for cholera (August 19, 158: 120) and tuberculosis (October 21, 158: 270).
• Biologists read the full DNA sequence of the fruit fly (February 26, 157: 132; June 10, 382) and discovered a sleeplike state in the insect (February 19, 157: 117*).
• A protein originally found in frogs appears to be the long-sought light detector for the human biological clock (February 19, 157: 120).
• A cold virus that produces obesity in mice and chickens seems to play a role in human corpulence (February 5, 158: 87).
• Seeking to explain how antibiotics work, scientists found a protein that commands bacteria to kill themselves (February 12, 157: 101).
• Researchers found that mice detect pheromones using nerve cells distinct from those of the main olfactory system (June 17, 157: 390).

Biomedicine

• Transplants of cells that make insulin boosted the potential for a cure for diabetes (March 11, 157: 165; September 2, 158: 156). A rapidly developing form of diabetes in children appeared to be the result of unrecognized chemicals or viruses destroying insulin-making cells (February 5, 157: 86*).
• Researchers discovered that people with a common version of the CAPN10 gene face an increased risk of getting adult-onset diabetes (September 30, 158: 212).
• Veterans who suffered a moderate or severe concussion during World War II showed a heightened risk of Alzheimer’s disease in old age (October 28, 158: 276). A vaccine intended to slow or prevent Alzheimer’s appeared promising (July 15, 158: 38*).f6 Ibuprofen seemed to lessen accumulation of beta-amyloid protein fragments in the brain, perhaps explaining how that common painkiller decreases Alzheimer’s risk (August 12, 158: 101*).
• As a strategy for slowing the development of bacterial resistance to antibiotics, researchers engineered drugs that self-destruct when exposed to sunlight (January 1, 157: 5). Other groups worked to defeat antibiotic resistance by disabling the drug-expelling pumps in the microbes’ cell membranes (February 12, 157: 110). When Denmark decreased its use of antibiotics in livestock, the prevalence of drug-resistant bacteria in meat fell (August 5, 158: 95).
• New research suggested that periodic treatment breaks for AIDS patients may boost their immune response against HIV (April 15, 157: 248). An experimental AIDS vaccine bolstered with two immune proteins protected rhesus monkeys from the disease (October 21, 158: 260*).
• Although gene therapy caused the death of a patient late in 1999, in 2000, the new technology recorded several successes. They include reversing an immune disease in babies (April 29, 157: 277), spurring bone repair in mice and rats (June 3, 157: 357), and curing hemophilia in mice (May 13, 157: 309). New methods of delivering genes promised to help gene therapy reach its potential (May 13, 157: 309). As a step toward reawakening neurons in people with spinal cord damage, a version of the polio virus delivered genes to motor neurons without harming them (September 9, 158: 166). Finally, lessons from gene therapy promoted viruses as cancer fighters (August 19, 158: 126*).
• Providing the first evidence in primates for effective inoculation against deadly Ebola virus, a vaccine combo tested well in monkeys (December 2, 158: 358). Also, Ebola proved to have a surface protein that kills cells lining blood vessels (August 5, 158: 85*).
• Scientists induced an immune response against pancreatic cancer by injecting blood cells from healthy people into patients’ tumors (April 1, 157: 214).
• Research showed that anticholesterol drugs called statins stimulate bone growth and that a protein known as osteoprotegerin prevents bone from breaking down (January 15, 157: 41*).b1 The protein also reduces bone cancer pain in mice (May 6, 157: 292*).
• A simple breath test may help physicians learn how people metabolize drugs and identify patients most likely to suffer side effects from chemotherapy (May 20, 157: 332).
• Tiny tubes of steel mesh coated with a DNA-containing polymer could prevent arteries from becoming reclogged after cardiovascular treatment (November 18, 158: 325).
• In chimpanzees, a new vaccine spurred an immune response against the malarial form that passes through the liver, and the response usually halted the parasite before it could cause disease (November 11, 158: 310).
• A study of twins showed that heredity plays a role in ear infections (February 26, 157: 136).
• Bacteria genetically engineered to secrete microbe-killing and anti-inflammatory compounds fought diseases in rats and mice (October 14, 158: 244*).
• Suggesting a potential therapy for people with strokes or Alzheimer’s disease, studies indicated that lithium, which is widely used to treat manic depression, stimulates production of new brain cells (November 11, 158: 309).
• Researchers explored the mechanisms underlying links between low birth weight and chronic disease (December 9, 158: 382*).
• A new study suggested that flawed insulin activity may lead to blood changes that foster atherosclerosis, even in people who aren’t diabetic (September 30, 158: 213).
• Scientists used patterns of gene expression to distinguish between two types of blood cancer that respond differently to treatment. (April 8, 157: 239).
• Diets with severely reduced calories showed signs of lengthening lives and reducing disease in monkeys (November 25, 158: 341*).
• Hypermethylation–a chemical alteration of DNA that can silence genes inappropriately–plays a role in nonhereditary breast cancer (April 15, 157: 247; June 24, 407). Signs of this alteration could help physicians screen patients for lung cancer (November 25, 158: 340).
• New studies found that the puzzling sleep disorder narcolepsy stems from destruction of a small group of brain cells (September 2, 158: 148).
• A 6-year study showed that vitamins and antibiotics can reverse conditions that lead to stomach cancer (December 16, 158: 391).

• The latest inventory of life in the United States turned up an extra 100,000 species of plants, animals, and fungi, but it warned of threats to at least a third of those species (April 1, 157: 219).
• Natural selection can act on large groups, according to a test on ecosystems that have thousands of species and were miniaturized to fit in flowerpots (July 15, 158: 39).
• A novel comparison of 25 pairs of insect lineages found that sexual conflict plays a major role in making new species (September 16, 158: 181).
• In a newly proposed scenario, hermaphroditic plants may evolve distinct gender forms in response to polyploidy (September 30, 158: 214).
• The microscopic bdelloid rotifer has seemingly evolved without sex for some 40 million years and probably doesn’t exist in male form– making this rotifer a good candidate for a robust asexual species, a much debated possibility (May 20, 157: 326*).
• After 5 years of mystery, California pathologists announced that a fungus probably causes the tree disease called sudden oak death (August 5, 158: 86).
• Marine iguanas in the Galápagos Islands are the first vertebrates known to reduce their size during a food shortage and then regrow to their original body length (January 8, 157: 20*).
• Full-grown elephants imported into a park of destructive youngsters demonstrated that when older males enter the aggressive, testosterone-driven state called musth, they suppress that condition in younger males (November 25, 158: 341).
• The eardrums of a tiny parasitic fly have a novel mechanism that enables the insect to pinpoint a sound’s origin as well as owls and people do (November 11, 158: 308).
• Researchers found a second bird genus in New Guinea that, like the pitohoui, carries toxins first identified in poison-dart frogs in Central and South America (October 21, 158: 263).
• A study suggested that sacs bulging from a horse’s auditory tubes keep the animal’s brain from overheating during exercise (January 29, 157: 69).
• New approaches to estimating age of bowhead whales in the Arctic suggested that some live much longer than expected, more than 200 year instead of just 60 (October 14, 158: 254).
• Pacific tree frogs downwind of California’s agricultural hotspots show reduced cholinesterase activity, a common symptom of pesticide exposure (December 16, 158: 391).

Chemistry

• Scientists developed a new titanium-producing process that may eventually reduce the metal’s cost to one-third its current price (September 23, 158: 197*).
• Researchers coerced argon to join other elements to form a stable, neutral compound (August 26, 158: 132).
• The first atomic-resolution map of a ribosome, the cell’s protein factory, suggests that RNA catalyzes the formation of proteins (August 12, 158: 100*).
• When physicists pulled out the inside cylinders of multiwall carbon nanotubes, the innards snapped back into place, suggesting that nanotubes could serve as frictionless bearings and springs (July 29, 158: 71).
• A conch’s tough shell resists fractures because protein surrounds the mineral crystals throughout the structure (July 1, 158: 6).
• Chemists devised a method for identifying cocaine’s geographical origin (November 18, 158: 324*).
• Carrying out a widely used chemical reaction on one molecule at a time, researchers demonstrated unprecedented control of molecular behavior (September 30, 158: 215*).
• Scientists coaxed green algae to produce hydrogen, a clean-burning fuel that could someday power pollution-free cars (February 26, 157: 134).
• Researchers synthesized what they suspect is the most powerful nonnuclear explosive known (January 22, 157: 54*).
• Nuclear-waste storage may be modified in accord with a new understanding of the basic chemistry of plutonium (January 15, 157: 39).
• Researchers replaced diamonds in a device for high-pressure studies with a new synthetic crystal that should allow work on larger samples of material than can be tested in the diamond devices (October 28, 158: 278).
• A novel electrochemical method improved the surface of stainless steel without making the metal brittle or prone to corrosion (October 21, 158: 263*).
• For the first time, researchers directly observed a protein begin to crystallize, and they found it has a peculiar shape (August 5, 158: 84*).
• Scientists identified the chemical responsible for the yellow hue of many flowers, moving a step closer to engineering sunny-colored designer buds (November 11, 158: 311).

• Scientists determined that temperatures of the northern Pacific within the past 2 years veered from one extreme to the other, potentially altering North American weather for a decade or so (January 29, 157: 69*).
• People’s activities, not volcanoes, proved to be the main source of ozone-depleting chlorofluorocarbons in the atmosphere (February 19, 157: 118).
• Airborne measurements showed that layers of smoggy, ozone-rich air from Asia can reach the United States (January 1, 157: 4).
• Satellite observations of clouds indicated that some types of airborne pollution can break up water droplets and suppress rainfall (March 11, 157: 164*).
• For the first time, scientists detected atmospheric SF5CF3, a greenhouse gas that traps heat more effectively than any other previously found in air (July 29, 158: 70).
• NASA studies showed that the vast center of Greenland’s ice sheet isn’t getting thinner, but most of its margins are, contributing to rising sea levels (July 22, 158: 54).
• Up to a quarter of the humanmade structures within 500 feet of America’s coastlines may be lost to erosion by 2060, according to a federal report (July 8, 158: 21).
• A Connecticut-size iceberg split from the Ross Ice Shelf in Antarctica (April 1, 157: 215).
• Satellite images confirmed that the northern United States had much less snow cover than normal this spring, following North America’s warmest winter on record (August 5, 158: 87).
• In one of the worst fire seasons in decades, wildfires seared the western United States throughout the summer (August 12, 158: 101).
• A new computer model suggested how earthquakes can happen at fault zones located far from the edges of a tectonic plate (September 30, 158: 212).
• A study of long-lasting fluctuations in the temperature and volume of water spewing from hydrothermal vents after an undersea earthquake suggested that the flow into vents is complex (September 16, 158: 183).
• A survey of Mount Everest altered its official elevation to 29,035 feet (January 1, 157: 11).
• Computer simulations found that a swath of unfrozen ocean may have hugged the Earth’s equator even during the most frigid global-climate episodes (May 27, 157: 343).
• Polar stratospheric clouds, which drive ozone loss in Antarctica, turned up in force during the most recent Arctic winter (June 3, 157: 356*).
• Mystery solved: Long-term fluctuations in pressure at the ocean’s bottom appear to drive the Chandler wobble, which causes the North Pole to wander a path of about 20 feet every 14 months (August 12, 158: 111).
• By analyzing impurities, researchers measured remnants of the gargantuan pressure that formed diamonds (October 21, 158: 260).
• Geologists said that significant portions of the Grand Canyon, usually considered the product of eons of erosion, may have been carved within the past million years or so (September 30, 158: 218).

Environment & Ecology

• Negotiators reached agreement on the draft of a treaty to ban or phase out some of the world’s most persistent and toxic pollutants (December 16, 158: 389).
• Scientists in the United States offered the first confirmation of something their European counterparts have been reporting for years–widespread drug pollution of surface, ground, and tap water (April 1, 157: 212*). Drug concentrations were at times high enough to alter the apparent gender of fish and, perhaps, their fertility (June 17, 157: 388*).
• Air concentrations of ozone in many areas are high enough to induce leakiness in people’s lungs, a study found (May 13, 157: 308*).
• Ballast water can move huge quantities of cholera germs and other microbes between ports around the globe (November 25, 158: 348).
• Satellite imagery showed that sprawling urban development is disproportionately gobbling up the land best able to support crops (March 4, 157: 155). Other analyses linked the traffic associated with urban sprawl to an unexpectedly large rain of pollutants into local waters (November 18, 158: 332).
• A government review concluded that young boys exposed to the phthalates in many plastics, cosmetics, and medical supplies could develop reproductive impairments (September 2, 158: 152*). Subsequent studies showed that these hormone mimics are present in U.S. residents and that they could be fostering premature breast development in girls (September 9, 158: 165*).
• A California study indicated that some cars’ catalytic converters foster the production of ammonia, a pivotal ingredient in the urban haze and in the particulate pollution that the devices were designed to reduce (August 26, 158: 133*).
• DDT and other estrogen-mimicking pollutants showed the capacity to transform male fish into mothers that produce viable young (February 5, 157: 87). At the same time, public health officials around the world lobbied to preserve DDT for killing malaria-carrying mosquitoes (July 1, 158: 12*).
• After reviewing new studies that demonstrated biological effects in animals and people exposed to cell-phone frequencies, a British review of research offered the devices a guarded endorsement (February 12, 157: 100*; May 20, 326).
• Studies confirmed that corn engineered to make a bacterial toxin–the Bt pesticide–can kill caterpillars of nontarget species (September 16, 158: 184). However, the Bt toxin in different corn strains varied widely in nontarget lethality (June 10, 157: 372*).
• The unusually invasive seaweed that has been smothering coastal seafloor areas of the Mediterranean showed up in California waters, prompting an immediate campaign to break the invaders’ toehold in the Americas (July 15, 158: 36*; August 5, 83; November 18, 332).
• A few neighbors burning trash that includes plastic may generate more toxic dioxins than a well-run municipal incinerator, analyses showed (January 29, 157: 70).
• Men who were exposed in the womb to dioxinlike pollutants from their mothers produce impaired sperm (November 4, 158: 303), researchers reported. Others found increased ratio of girls to boys among the offspring of men who had high dioxin exposures (June 3, 157: 358).

• The National Institute of Medicine increased the recommended daily intake of dietary antioxidants, such as vitamins C and E (April 15, 157: 244).
• Studies found that for bone health, there is little carryover benefit from calcium supplementation once it ends (April 22, 157: 260*). Other research showed that calcium, especially from dairy products, can switch the body’s fat cells from storing calories to burning them (April 29, 157: 277*).
• U.S. cattle were shown to have high rates of toxic bacterial infections that lead to widespread carcass contamination at slaughter (March 25, 157: 199).
• A study found that consuming lots of oranges, other citrus fruits, or citrus juices can raise the concentrations of good cholesterol in a person’s blood (November 18, 158: 327).
• Though a new study found that drastic salt restriction can lower blood pressure, even in people without hypertension, some critics challenged the finding’s value in setting guidelines for all adults (May 27, 157: 340).
• Preliminary studies indicated that moderate consumption of chocolate may offer cardiovascular benefits (March 18, 157: 188*).
• Low-fat diets may greatly increase heart-disease risk in people who have impaired insulin action, including many without diabetes, researchers found (April 8, 157: 236).
• The federal government approved irradiation of raw meat, the only technology known to kill an especially lethal strain of bacteria (January 15, 157: 40).
• A study of vitamin E found that megadoses may reduce the risk of heart disease in people with diabetes and other conditions that produce chronic, low-grade inflammation (November 11, 158: 311).
• University scientists developed biodegradable plastics that release natural germ-killing agents to the foods wrapped in them (September 30, 158: 221).
• Dutch neuropsychologists reported that drinking a milk-derived protein that yields a mood-enhancing amino acid may help vulnerable people cope with stress (July 8, 158: 23).

Mathematics & Computers

• In an unexpected result concerning partitions, which are whole numbers written as sums of smaller numbers, mathematician Ken Ono proved there are infinitely many partition congruences (June 17, 157: 396*).
• The data-scrambling technique called Rijndael won the worldwide competition to become the federal government’s advanced encryption standard (October 7, 158: 231).
• A new theorem opened a path to a proof of Catalan’s conjecture, a venerable problem concerning consecutive powers of whole numbers (December 2, 158: 356).
• Researchers in computational geometry demonstrated that any crinkled polygon can be unfurled into a convex shape without letting the sides cross each other (September 23, 158: 200*).
• Mathematicians reached a milestone in algebraic number theory by proving the local Langlands correspondence, a conjecture that concerns prime numbers and perfect squares (January 15, 157: 47).
• Proved: The standard double-bubble configuration, familiar to soap-bubble enthusiasts, represents the least surface area when the two bubble volumes are unequal (January 29, 157: 77).
• The malicious ILOVEYOU computer virus, spread via an E-mail attachment, shut down hundreds of thousands of computers and caused several billion dollars in damage around the world (May 27, 157: 351).
• A quantum computation using a custom-built molecule with five fluorine atoms furnished experimental evidence that a quantum computer can solve certain mathematical problems more efficiently than a conventional computer can (August 26, 158: 132*).
• Studies provided insight into the vast extent, intricate structure, and robustness of the World Wide Web (May 27, 157: 351; August 19, 158: 125).
• The Goldbach conjecture–that every even number is the sum of two primes–was shown to be true up to 4.5 x 10^14 (August 12, 158: 103).

Paleobiology

• A fossilized dinosaur heart similar to that of birds and mammals provided further evidence that dinosaurs may have been warm-blooded (April 22, 157: 260*).
• A supposed missing link between dinosaurs and birds turned out to be fossil fakery that combined bones from two different animals (January 15, 157: 38*).
• The massive extinctions at the end of the Permian period 250 million years ago could have occurred within a mere 8,000 years, scientists suggested (July 15, 158: 39).
• An anatomically primitive, 92-million-year-old ant, trapped in amber, pushed back the first record of its subfamily by 40 million years (November 25, 158: 343).
• Paleobiologists said that tiny fossils from the ears of fish that survived worldwide extinctions about 34 million years ago suggest that cooler winters caused the die-off (October 28, 158: 287).
• Researchers found that Caudipteryx, a feathered animal that lived 120 million years ago, may have been a flightless bird, not a bird ancestor (August 19, 158: 119).
• Fossil tracks of an unknown bird from 110-million-year-old Korean sediments pushed back evidence of web-footed birds by at least 25 million years (August 12, 158: 111).
• The bones of six carnivorous dinosaurs discovered in a fossil bed in Patagonia indicated that the big meat eaters were social creatures (April 1, 157: 223)

Physics

• An experiment confirmed the existence of the tau neutrino (July 29, 158: 68), last of the 12 fundamental subatomic building blocks of matter. Possible sightings of the Higgs boson–a long-sought particle thought to confer mass on other particles–hint that it may also turn up soon (September 23, 158: 196*; November 4, 294*; December 9, 381).
• A European particle accelerator may have produced the first traces of a primordial state of matter called the quark-gluon plasma (February 19, 157: 117*). A new, more powerful, U.S. accelerator began experiments also intended to make that plasma (August 26, 158: 136*).
• Sparking controversy, a theorist suggested that electrons in liquid helium can break into pieces dubbed electrinos (September 30, 158: 216*).
• Experiments demonstrated that pulses of electromagnetic radiation can outpace light’s nominal speed limit of 300 million meters per second, fueling more debate over whether information also can travel at superluminal speed (June 10, 157: 375*).
• Physicists combed experimental data for newly predicted signs that extra spatial dimensions exist and alter gravity (February 19, 157: 122*). A new measurement found only normal gravity down to as little as a 0.2 millimeter separation between masses (May 13, 157: 311).
• A novel technique promised to make ultraprecise measurements of light frequencies widespread (June 3, 157: 359*).
• Observations of mad dancing by tin atoms on a copper crystal overturned conventional ideas of how bronze and other alloys form on surfaces (November 25,158: 340*).
• Researchers built a device that, with electrical and magnetic properties contrary to those of ordinary materials, is expected to respond to microwave radiation in extraordinary ways (March 25, 157: 198).
• Accelerator experiments confirmed predictions that electrons orbiting an atom’s nucleus can directly excite the nucleus (September 23, 158: 207).
• Atomic physicists demonstrated matter amplification that’s analogous to amplification of light in a laser beam (January 1, 157: 15).
• The quantum nature of mechanical vibration and heat flow became evident in an experiment probing heat dissipation in nanometer-scale structures (April 29, 157: 279).
• Molecules were made in ultracold atom clouds called Bose-Einstein condensates (BEC)–a possible step toward molecular BECs (February 12, 157: 104).

Technology

• Researchers wired the living brain of a sea lamprey to a small, wheeled robot in the first example of two-way communication between neurons and a machine (November 11, 158: 309*).
• Interactions between strands of DNA served as fuel to power tiny machines, including one made of DNA (April 15, 157: 246; September 2, 158: 159).
• Despite looming fundamental limits, electronics researchers raced to find new ways to continue shrinking microcircuit components (March 25, 157: 204*; November 25, 158: 350*).
• Better feed, medicines, and water tanks improved the outlook for fish farms that recirculate water and thereby cut pollution (May 13, 157: 314*).
• Manufacturers debuted industrial-grade cables, motors, and other power devices made with high-temperature superconductors–materials that carry electricity without resistance at temperatures well above absolute zero (November 18, 158: 330*).
• Tissue engineers created a crude artificial nose and an artificial thymus by growing cells on scaffolds of carbon and polymer foam, respectively (March 4, 157: 149; July 22, 158: 63).
• Bringing nearer to fruition microchips that process light, instead of electrons, fabrication advances improved the properties of artificial optical materials known as photonic crystals (June 17, 157: 399; September 2, 158: 159)