Science News of the Year 2001

The year 2001 will be remembered sadly for a single date: Sept. 11. The horrific loss of lives to terrorism on that day overshadows all earlier events of the year. The fear instilled on Sept. 11 was soon exacerbated by bioterrorism, as anthrax spores sent through the mail caused additional deaths and provided a threat that seemed it might reach into any home or workplace. People immediately looked to science for tools to protect them against terrorism.

Researchers who study microbes have been called upon to help investigators identify anthrax spores, to come up with effective means to decontaminate office buildings, to design therapies for people who may have been exposed to anthrax and those showing symptoms of infection (SN: 10/20/01, p. 246), and to develop plans to guard the public against future attempts at mass murder. Attention turned to recent results exploring the basic biology of anthrax (SN: 10/27/01, p. 260) and potential antidotes (SN: 10/6/01, p. 212).

Data being collected from the devastation of the World Trade Center could lead to building codes that make structures safer for their occupants (SN: 11/24/01, p. 324). Designing a building to withstand the impact of a jet plane moving at full speed is a challenge that previously had been inconceivable.

The threat of terrorism also makes people worry about misuse of scientific findings. There’s fear that terrorists will steal microbes from research labs or use published data to create deadly agents. Iowa State University chose to destroy its anthrax collection rather than find a means to protect it adequately. Some scientists worry that terrorists could create a microbe de novo from published DNA sequences, while others regard that possibility as far-fetched.

Despite its tragic events, 2001 should also be remembered for its scientific achievements. We list here some of the most important ones.

—Julie Ann Miller, Editor

Anthropology & Archaeology Astronomy Behavior Biomedicine Botany & Zoology Cell & Molecular Biology Chemistry

Earth Science Environment & Ecology Food Science & Nutrition Mathematics & Computers Paleobiology Physics Technology

This is a review of important science stories of 2001 reported in the pages of Science News. The reference after each item gives the date and the volume and number of the page on which the main article on the subject appeared (vol. 159 is January–June; vol. 160 is July–December). An asterisk (*) indicates that the text of the item is available to any visitor to Science News Online. Registered Science News subscribers, once signed in, have access to the full text of all articles. The full text of an article can also be purchased for $2.50 from ProQuest (http://pqasb.pqarchiver.com/sciencenews).

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Anthropology & Archaeology

• In Ethiopia, fossils emerged that traced to more than 5 million years ago and appeared to belong to the earliest known member of the human evolutionary family (July 14, 160: 20*).
• The discoverers of a 3.5-milllion-year-old skull in Kenya said that the find came from a previously unrecognized line of ancient human ancestors (March 24, 159: 180*).
• A 4,000-year-old Peruvian site yielded the remains of the oldest known city in the New World (April 28, 159: 260*).
• About 1.5 million years ago, a group of humanity’s ancestors reached southeastern Asia (April, 21, 159: 246) and others ventured into frigid northeastern Asia (Sept. 29, 160: 199).
• Radiocarbon data inspired a theory that Middle Eastern farmers rapidly colonized southern Europe 7,400 years ago (Nov. 17, 160: 308).
• African-looking features of prehistoric human skulls unearthed in Brazil raised questions about the origins of the first Americans (April 7, 159: 212*).
• Scientists probed ancient fossils for clues to the evolution of human growth patterns (June 2, 159: 346*). One study suggested that Neandertals’ skulls developed differently from those of modern humans (Aug. 4, 160: 71). Another project indicated that slowed-down tooth growth may have emerged relatively recently among our fossil ancestors (Dec. 8, 160: 357).
• Fossil teeth found at a 30-million-year-old site in Pakistan suggested that lemurs have Asian roots (Oct. 20, 160: 245).
• Fierce debate arose over the ethics and implications of fieldwork with South America’s Yanomami people (Jan. 27, 159: 58).
• Genetic data indicated that female chimps mate outside their home groups less often than researchers had previously thought (Oct. 27, 160: 262).
• A fossil jaw offered a look at the caring side of Neandertals (Sept. 15, 160: 167*).
• Far-flung goat populations revealed a surprising amount of genetic unity that may reflect widespread trading of these animals in ancient times (May 12, 159: 294).
• New finds showed that people adapted to harsh environments at the end of the Stone Age (July 7, 160: 7).

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Astronomy

• For the first time, researchers detected the atmosphere of a planet that lies beyond the solar system (Dec. 1, 160: 340*).
• Discovery of a trove of planets orbiting stars other than the sun suggested that astronomers had finally found a planetary system similar to our own (Aug. 18, 160: 100*, Nov. 10, 299). Two other newfound planetary systems feature a bizarre entourage of orbiting bodies and may provide fresh insight into planet formation (Jan. 13, 159: 22*). One team of researchers retracted a controversial claim that some extrasolar planets were, in fact, much heavier bodies (Nov. 10, 160: 299).
• A spacecraft for the first time landed on the asteroid 433 Eros (Feb. 17, 159: 103). Data collected before and after the landing shed new light on the rock’s origins and composition (June 2, 159: 341; July 21, 160: 38, Aug. 18, 105, Oct. 27, 264).
• Experiments examining the relic radiation from the Big Bang confirmed cosmologists’ basic model of how the universe evolved (April 28, 159: 261).
• Astronomers detected signs of one of the earliest eras in the universe, just before the first stars and quasars flooded the cosmos with light (Aug. 11, 160: 84*).
• Scientists reported that they had measured the age of the cosmos with unprecedented accuracy (Oct. 27, 160: 261).
• According to a controversial new theory, the Big Bang was ignited when a parallel universe moving along a hidden dimension smacked into our cosmos (Sept. 22, 160: 184*).
• Scientists found additional evidence that some mysterious force is pushing galaxies apart at an ever-faster rate (March 31, 159: 196, April 7, 218*).
• Researchers found a clump of stars that may be one of the first building blocks of a galaxy (Oct. 6, 160: 215).
• Telescopes tracked the rise and fall of the largest dust storm observed on Mars in 25 years (July 28, 160: 53, Nov. 10, 299).
• A body as massive as Mars may once have resided in a region of the solar system far beyond the nine known planets and might still reside there (April 7, 159: 213*).
• Astronomers found evidence of a star that has swallowed one or more of its planets (May 19, 159: 310).
• Some planets may be free-floating in space rather than orbiting a star (May 19, 159: 313).
• Astronomers may finally have glimpsed a key step in the construction of a planet (May 5, 159: 278) and found what may be the youngest star known to have formed the building blocks of planets (Nov. 24, 160: 326).
• A nearby star appeared to have its own asteroid belt (June 16, 159: 375*), whereas another may possess comets (Aug. 18, 160: 105).
• Theorists proposed that the cell-like envelopes in which life on Earth evolved literally dropped from the sky (Feb. 3, 159: 68*). Simulating extraterrestrial impacts on Earth, researchers fired away at the question of how life started (May 19, 159: 317*).
• Researchers discovered sugars and sugar-related compounds in meteorites, bolstering the view that rocks from space delivered key ingredients for life on Earth (Dec. 22&29, 160: 388*).
• An X-ray outburst provided compelling new evidence that a monster black hole lurks at the Milky Way’s core (Sept. 8, 160: 148).
• A new analysis of a Mars meteorite suggested that water once flowed on the surface of the Red Planet and came from eruptions of molten rock deep within the planet (Feb. 24, 159: 123). A new study added to the evidence that past volcanic activity could have briefly created a warmer, wetter Mars (March 24, 159: 184).
• A spacecraft took the first X-ray image of Venus (Dec. 8, 160: 356).
• The 11-year cycle of solar storms reached its peak and disturbed satellites as well as electric-power systems on the ground (Jan. 13, 159: 26*, March 3, 139, April 28, 267). Astronomers obtained the first clear picture of the structure beneath a sunspot (Nov. 17, 160: 310).
• Observations challenged the notion that supermassive black holes stopped growing soon after their host galaxies formed, and the data suggested new ways to find and measure these black holes (Jan. 6, 159: 6*).
• Studies provided evidence of event horizons, the one-way membranes that surround black holes (Jan. 22, 159: 38). Observations suggested that black holes spin like dervishes (May 12, 159: 294) and that energy flows out from the vicinity of a black hole (Nov. 3, 160: 277).
• For many skywatchers in North America, Asia, and Australia, this year’s Leonid

  meteor shower was a true dazzler (Nov. 10, 160: 293*, Dec. 22&29, 395).

• Two spacecraft jointly spotted towering new volcanic plumes on Jupiter’s moon Io (April 14, 159: 232). One plume was 500 kilometers- high, the tallest ever seen on Io (Oct. 27, 160: 264).
• Astronomers imaged the largest known member of a reservoir of comets in the outer solar system; the icy body is bigger than Pluto’s moon Charon (July 21, 160: 41).

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Behavior

• Scientists uncovered a rare aspect of brain development that may be unique to people (Sept. 1, 160: 132*).
• A genetic mutation identified in members of a British family appeared to influence language capability (Oct. 6, 160: 213*). Deaf kids who invented their own sign language contributed to the debate over language and grammar origins (July 28, 160: 54).
• Behavior training combined with a low dose of Ritalin showed promise as a treatment for teenagers with attention-deficit hyperactivity disorder (June 2, 159: 343).
• Nicotine addiction showed signs of increasing over the past 20 years among young cigarette smokers (Sept. 22, 160: 183*).
• In separate studies, depressed people exhibited the same brain changes in response to either psychotherapy or antidepressant drugs (July 21, 160: 39).
• Babies’ penchant for conversing wordlessly with their caregivers may influence later social and emotional development (June 23, 159: 390).
• Scientists tied schizophrenia to the activity of a particular brain chemical (Sept. 8, 160: 150) and a virus (April 14, 159: 228). European and U.S. schizophrenia treatment expanded beyond medication alone (April 28, 159: 268*).
• An emerging field of study mined the intuitive strategies that children use to understand math and grasp other types of knowledge (March 17, 159: 172).
• New studies tapped into extensive interactions among brain cells involved in sight, hearing, and other senses (Sept. 29, 160: 204).
• Long-term data linked a positive outlook (May 26, 159: 324*) and healthy habits early in life (June 16, 159: 373*) to longer survival in old age.
• Brain researchers probed the vexing domains of dreaming (Aug. 11, 160: 90*) and mystical experience (Feb. 17, 159: 104*).
• Math anxiety showed signs of harming college students’ memory, thereby dragging down their math performance (June 30, 159: 405*).
• Controversial studies explored the possibility that people have an innate ability to recognize faces (July 7, 160: 10*).
• Some police officers displayed a surprising aptitude for lie detection, whereas others were often duped (March 3, 159: 133*).

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Biomedicine

• President Bush decided to permit limited research on human embryonic stem cells (Aug. 18, 160: 105). Scientists learned how to transform those cells into insulin-secreting and heart cells (Sept. 1, 160: 143) and blood and bone marrow cells (Sept. 15, 160: 175).
• A compound called polyvalent inhibitor, tested in rats, disabled the toxin that causes the deadly symptoms of anthrax (Oct. 6, 160: 212*). Also, scientists located the protein to which the anthrax toxin attaches when it attacks a cell (Oct. 27, 160: 260*).
• A protein-based drug injected into people with early signs of diabetes stopped the disease in its tracks (Dec. 1, 160: 341).
• Drugs for high blood pressure showed signs of forestalling kidney damage in people with type II diabetes (Sept. 22, 160: 182). Data indicated that blood pressure on the high end of normal should be treated to prevent heart problems or stroke (Nov. 3, 160: 277).
• A cell-surface molecule that normally binds to the vitamin folate permits Ebola virus to invade cells (July 21, 160: 36*).
• Transplanting muscle cells or stem cells into ailing hearts showed promise of curing heart failure (Jan. 13, 159: 30). Investigators learned how to transform fat cells into cartilage, the oft-injured joint tissue (March 3, 159: 134).
• Scientists seeking links between obesity, diabetes, and heart disease implicated a protein called resistin (Jan. 20, 159: 36)* and a family of proteins that regulate fat (April 14, 159: 238).
• Among people in intensive care units who require assistance breathing, keeping blood concentrations of sugar within normal limits nearly doubled survival (June 30, 159: 404*).
• Cholesterol-lowering drugs known as statins may fight Alzheimer’s disease (Feb. 10, 159: 92*). Surprising evidence suggested that amyloid plaques in the brain aren’t the main culprit in this illness (Nov. 3, 160: 286).
• A drug that blocks a protein called HER2 helped women with aggressive breast cancer live longer (March 17, 159: 167). The drug anastrozole outperformed tamoxifen against some breast cancers (Nov. 24, 160: 327*).
• Researchers began identifying genes and lifestyle factors that enable some people to live more than 100 years (March 10, 159: 156*).
• An increased capability to make the cancer-suppressing protein p53 could explain why women who have had a full-term pregnancy at an early age are less likely to get breast cancer (Oct. 20, 160: 247).
• A gene therapy thwarted sickle-cell disease in mice (Dec. 15, 160: 372*).
• Two new drugs tested in monkeys stopped menstrual bleeding and suggested a treatment for severe monthly bleeding that causes anemia (Aug. 18, 160: 102).
• Scientists gained insight into how cancer cells spread in the body (June 2, 159: 351).
• Women who bear sons in a pregnancy complicated by preeclampsia convey risk of the condition to their future daughters-in-law (March 24, 159: 181).
• Neuroscientists showed that the hormone secretin, a controversial autism therapy, has a role in the brain (Nov. 17, 160: 314).
• Scientists sought to explain why women are more susceptible to autoimmune diseases than men are (July 28, 160: 58).
• Genes implicated in Crohn’s disease (May 26, 159: 327) and lung cancer were identified (May 12, 159: 294).
• Blindness in premature infants could stem from a shortage of a protein called insulin-like growth factor 1 (July 7, 160: 8).
• An antimicrobial chemical common in soaps and mouthwashes showed that it might help fight malaria (Feb. 17, 159: 102). Scientists tracked how variants of the disease have spread across the globe (Nov. 10, 160: 296*).
• Scientists worked to understand what underlies the placebo effect—if there is one (Feb. 3, 159: 74; Sept. 15, 160: 175).
• A study found that the body’s reaction to sleep deprivation resembles insulin resistance, suggesting a link between sleep loss and type II diabetes (July 14, 160: 31).
• Medical histories of HIV-positive people suggested they face an increased risk of coronary artery disease (Sept. 8, 160: 149*).
• By unraveling the molecular signals that guide hair growth, scientists moved toward helping people avoid growing too much or too little hair (Oct. 20, 160: 254).
• Scientists engineered a poliovirus to make it attack brain tumors (May 26, 159: 326).
• Researchers tricked leukemia cells into committing suicide by trapping cancer-

  promoting proteins in the cells’ nuclei (Feb. 10, 159: 84).

• Antioxidant vitamins didn’t appear to prevent heart disease (Aug. 11, 160: 87, Dec. 1, 351).
• Chronic jet lag shrinks parts of the brain, a preliminary study suggested (June 23, 159: 392).
• Although some people claim child vaccinations are risky, studies indicated that the shots are broadly beneficial (Aug. 18, 160: 110*).

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Botany & Zoology

• The first systematic survey of the inside of a coral reef revealed abundant filter feeders, which may be as important to reef function as the outside creatures are (Oct. 20, 160: 244).
• Scientists cloned the rare, oxlike gaur, but a common infection killed the calf (Feb. 10, 159: 95*). A second cloned rarity, a mouflon sheep, has survived (Oct. 20, 160: 252*).
• A magnetic field simulating the takeoff point for birds flying over the Sahara cues them to fatten up (Nov. 3, 160: 278).
• Scrub jays that have stolen food from other birds’ caches hide their own with extra care, which suggests that birds have surprisingly fancy cognitive processes (Nov. 24, 160: 325).
• A test on working longline fishing boats found that an inexpensive array of streamers reduces accidental killing of seabirds more than 90 percent (Aug. 25, 160: 117).
• Greenish warbler populations encircling the Tibetan Plateau were viewed as evidence of a long-sought evolutionary phenomenon called a ring species (Jan. 20, 159: 40).
• Merely handling a plant’s leaves may skew studies of its reactions to predators (Feb. 24, 159: 119).
• Invading Argentine ants can, by themselves, shift the mix of plant species in a South

  African ecosystem (Oct. 20, 160: 252).

• A fungus on tree roots kills soil insects and passes nitrogen to the tree (April 7, 159: 213).
• The largest review yet of wild parrot nesting found both frequent poaching and evidence that a U.S. law curbs trade (June 2, 159: 343).
• A genetic study of African elephants suggested that forest dwellers are a species separate from those roaming savannas (Sept. 8, 160: 155). And as more insight for managing elephants: Older matriarchs tell friends from strangers far better than younger females do (April 21, 159: 244*).
• A second kind of bacterium, besides Wolbachia strains, causes arthropod versions of virgin birth (Oct. 27, 160: 263). The infection switches mite males’ gender so that they reproduce as virgins—creating the only animal species yet discovered to live and reproduce with only one set of chromosomes (June 30, 159: 405).

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Cell & Molecular Biology

• Two teams presented the first analyses of the full human genome and estimated that it contains only about 30,000 genes (Feb. 17, 159: 100*).
• A biotech firm’s claim to have created the first cloned human embryos reignited scientific and political controversy (Oct. 20, 160: 250*, Dec. 1, 341*).
• Scientists created the first genetically engineered primate, a rhesus monkey (Jan. 20, 159: 38).
• Geneticists deciphered all the DNA of several disease-causing bacteria— including ones that cause typhoid fever, food poisoning, and the plague (Feb. 3, 159: 71, May 12, 296; Nov. 24, 160: 332)—and two species of puffer fish (Nov. 3, 160:276).
• Neuroscientists established that brain cells called glia have several crucial roles (April 7, 159: 222), such as providing the cholesterol that nerve cells need to form connections with each other (Nov. 17, 160: 309*).
• Microbiologists unexpectedly revealed that bacteria have an internal protein skeleton similar to that of human cells (March 31, 159: 198*).
• Taste researchers identified a gene encoding a protein that enables the tongue to sense sweets (April 28, 159: 263).
• Obscure chemicals called trace amines have receptors on brain cells and may play a role in depression and schizophrenia (July 21, 160: 37).
• Scientists identified a new potential contraceptive target—a protein that helps mammalian sperm wiggle their tails (Oct. 13, 160: 228*).
• A hormonal derivative of vitamin A helps coordinate the body’s internal clocks (July 14, 160: 22).
• Agricultural scientists created the first salt-tolerant tomato plant (Aug. 4, 160: 68*).
• Developmental biologists observed that nascent blood vessels provide signals that help spark the creation of organs, such as the liver (Sept. 29, 160: 198*), and identified genes controlling the heart’s creation (July 7, 160: 4,13).
• Human sweat proved to contain a microbe-killing protein (Nov. 10, 160: 292*).
• Investigators found that a stress hormone shields an embryo from its mother’s immune system (Oct. 20, 160: 247) and identified cell-surface proteins, called toll-like receptors, that recognize microbes (Sept. 8, 160: 152*).
• Aging cells can stimulate their neighbors to become tumors (Oct. 6, 160: 214).

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Chemistry

• New calculations showed that quantum mechanics determines ethane’s most stable structure (June 2, 159: 340*).
• Researchers found that the common mineral calcite can segregate amino acids into right- and left-handed varieties (May 5, 159: 276*). Other experiments revealed how the orientation of amino acids can make a crystal take on either a right- or left-handed form (June 16, 159: 373).
• A new ceramic stretches to 10 times its original length in record time (Sept. 22, 160: 181).
• Water droplets sprint across a surface under the influence of a unique chemical coating (Jan. 27, 159: 55).
• A surface material demonstrated a built-in ability to kill bacteria (May 26, 159: 325).
• Researchers made individual superconducting carbon nanotubes just 0.4 nanometers wide (Aug. 4, 160: 79).
• A new catalyst reduces pollution from a chemical reaction widely used in industry (Aug. 25, 160: 126).
• Researchers created tiny bar codes to label molecules (Oct. 6, 160: 212).
• New films indicate the presence of airborne chemicals by changing color (Aug. 18, 160: 103).
• A fresh technique for treating paper pulp emerged, and it could help clean up the papermaking industry (Nov. 10, 160: 292).
• Researchers made crystals that reversibly change their surface shape when exposed to light (March 17, 159: 175).
• Unusual titanium dioxide coatings break down toxins and keep mirrors from fogging (July 14, 160: 22).
• Some nonstick coatings such as Teflon break down at high temperatures into undesirable compounds that persist in the environment (July 21, 160: 36*).
• By applying a coating that releases nitric oxide, scientists prevented bacteria from building up on materials (Sept. 15, 160: 165).
• A new detector rapidly distinguishes between almost identical DNA molecules (March 24, 159: 180).
• Researchers reported that bones’ resilience could result from so-called sacrificial bonds—easily broken bridges in or between collagen molecules (Dec. 15, 160: 374).

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Earth Science

• The discovery of a new type of undersea hydrothermal vent system suggested that such outlets may be surprisingly widespread (July 14, 160: 21*).
• Occasional sediment-rich plumes of fresh water dumped into the ocean by rivers may convey pesticides and nutrients to the seafloor (Nov. 17, 160: 308*).
• Ocean-floor sediments drilled from Antarctic regions once covered by ice shelves provided evidence that those shelves are much younger than scientists had held (Sept. 8, 160: 150).
• A newly discovered group of hydrothermal vents in the Indian Ocean is surrounded by ecosystems that differ significantly from those at other vent systems (Sept. 15, 160: 165).
• Comparisons of satellite data provide direct evidence that the atmosphere’s greenhouse effect increased significantly between 1970 and 1997 (March 17, 159: 165).
• Analysis that includes a forest’s moisturizing effect on regional climate indicated that the Amazon rainforest could disappear in the next 3 decades (July 14, 160: 24).
• Building the Three Gorges Dam across the Yangtze River in China may lead to warmer temperatures in Japan (April 21, 159: 245*).
• Ground vibrations produced by the collapsing twin towers of the World Trade Center in lower Manhattan were recorded by instruments up to 425 kilometers away (Nov. 24, 160: 324*).
• Large-scale deforestation in the eastern lowlands of Central America is affecting weather in the mountains downwind and imperiling ecosystems there (Oct. 20, 160: 245).
• New observations of the atmosphere over polar regions may require scientists to revamp their models of environmental conditions at high altitudes (April 7, 159: 215).
• The inactivity of a single enzyme in peat might alone be preventing massive releases of carbon dioxide from peat lands (Feb. 10, 159: 95).
• In a previously unrecognized phenomenon, microorganisms found in Kentucky shale are eating the carbon locked within the rocks’ kerogen (March 31, 159: 198).
• Above-average hurricane activity in the North Atlantic during the past 6 years may signal a threatening weather trend (July 21, 160: 37).
• Better measurements of a radioactive-decay rate suggested that Earth may have had a crust up to 200 million years earlier than geologists had expected (Aug. 25, 160: 127).
• Principles of quantum physics may explain why seismic waves travel at different speeds in different directions across Earth’s inner core (Sept. 22, 160: 191).
• Researchers monitoring small ground motions along faults in Southern California also detected the ground’s rise and fall when local governments pumped water into and out of the region’s aquifers (Aug. 25, 160: 119).
• Computer models developed to analyze seismic vibrations traveling through uneven terrain can also identify and track heavy vehicles, such as tanks (June 16, 159: 381).

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Environment & Ecology

• The United States and 126 other nations signed a treaty to phase out major persistent, toxic pollutants (June 2, 159: 343).
• Negotiators in Bonn, Germany, without input from U.S. representatives, resolved controversies blocking an international treaty to limit greenhouse gases (July 28, 160: 54).
• At exposures well below those deemed acceptable by the U.S. government, lead impairs a child’s learning (May 5, 159: 277). Treatment to remove that lead fails to curb impairment, even in kids who’d been only moderately exposed (May 12, 159: 292*).
• Some river pollution spawns body-altering steroids (Jan. 6, 159: 8*).
• Research suggested that long-range movement of dust can sicken wildlife, crops, and people a continent away (Sept. 29, 160: 207, Oct. 6, 218*).
• After a heavy die-off, Caribbean urchins are poised for a comeback, which could help save area corals (Aug. 25, 160: 120*).
• New studies showed coastal no-fishing zones aid the recovery of fish stocks, to the benefit of fishing fleets (April 28, 159: 264).
• Breathing fine airborne dust triggers adverse heart changes in even strong, healthy workers (July 7, 160: 9, Sept. 15, 167).
• Landfill disposal of mercury can transform the pollutant, making it more toxic and likely to enter the air (July 7, 160: 4*).
• Government agencies began developing joint policies to reduce the huge, seasonal dead zone in the Gulf of Mexico (Feb. 3, 159: 79). New findings indicated that by using a little less fertilizer, farmers could play a role in limiting the zone (Nov. 10, 160: 295).
• Regional climate changes triggered by large-scale deforestation in some Central American lowlands are affecting weather—and imperiling ecosystems—in the mountains downwind (Oct. 20, 160: 245).
• A major report concluded that genetically engineered Bt corn poses a “negligible” risk to butterflies (Sept. 15, 160: 164). However, bits of genes put into bioengineered corn turned up in old types of maize in remote parts of Mexico (Dec. 1, 160: 342).
• Studies linked elevated residential electromagnetic fields to reduced production of the hormone melatonin (Oct. 6, 160: 215). Women who work the graveyard shift increase their chance of developing breast cancer, apparently by suppressing that hormone (Nov. 17, 160: 317).
• Hatchery fish appeared to be not only replacing some wild populations of their species (June 2, 159: 342*) but also spreading a deadly fungus to wild amphibians (Aug. 4, 160: 71).
• The European Union provisionally voted to ban use of most polybrominated diphenyl ethers, a family of flame retardants (Sept. 29, 160: 207). U.S. studies found these potentially toxic pollutants in people and the environment (Oct. 13, 160: 238*).
• Adults who had eaten fish tainted with polychlorinated biphenyls had problems with learning and memory (June 16, 159: 374).

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Food Science & Nutrition

• A large share of meats and seafood comes from the grocery store bearing bacteria invulnerable to many drugs, so these microbes could cause serious infections (May 26, 159: 325; Oct. 20, 160: 246*).
• New food labeling will identify foods rich in choline, a nutrient that can play an integral role in learning and brain health (Nov. 3, 160: 282*).
• One arcane family of trans fats may be tapped to treat or prevent a host of diseases (March 3, 159: 136*). Researchers are finding ways to reduce the presence of other, unhealthful trans fats in food (Nov. 10, 160: 300).
• In animals, foods that break down quickly into simple sugars appeared to foster obesity and diabetes (Feb. 17, 159: 111).
• Largely ignored, dietary boron may play a role in preventing diseases such as arthritis and prostate cancer (April 14, 159: 228*).
• How the body metabolizes fat depends on whether the mouth got a taste of it, a new study found (Dec. 8, 160: 359).
• Tainted livestock feed can lead to residues of PCBs and related pollutants in meat (Feb. 3, 159: 79).
• Calcium supplements may limit the body’s uptake of lead, a toxic heavy metal (March 31, 159: 205).
• Norwegian scientists linked high milk consumption to a low incidence of breast cancer (Sept. 1, 160: 135).
• Researchers suppressed the growth and spread of breast cancer in animals by removing two antioxidant vitamins from the diet (April 21, 159: 248).
• Lutein, a yellow pigment in many fruits and vegetables, may inhibit processes that jump-start atherosclerosis (June 23, 159: 391).
• Vitamin E warded off osteoporosis in mice and served as an immunity-enhancing growth promoter in cattle (June 30, 159: 410; July 7, 160: 8).
• Drinking just 1 to 3 cups of coffee daily may adversely affect blood concentrations of cholesterol and homocysteine (Sept. 22, 160: 180).

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Mathematics & Computers

• A tantalizing link between number theory and chaotic dynamics offered a potential path to a proof that every decimal digit of pi occurs with the same frequency (Sept. 1, 160: 136*).
• Two mathematicians established a ceiling on the number of so-called Reidemeister moves required to unravel a tangled circle (Dec. 8, 160: 360).
• Researchers discovered a remarkable formula relating the curvatures and coordinates of tangent circles packed within a circle (April 21, 159: 254*).
• Scientists demonstrated that the procedures governing communication between computers linked to the Internet can be co-opted to perform computations without the consent of the targeted computers (Nov. 17, 160: 318*).
• Several government initiatives aimed to develop computing power in the range of 12 trillion operations per second or more for research use (Aug. 25, 160: 118).
• Mathematicians made substantial progress in developing new formulas for enumerating representations of numbers as the sums of squares (June 16, 159: 382).
• Damage caused by the Code Red worm and several other viruses in July and August focused new attention on rogue computer programs that could bring down the Internet (Aug. 25, 160: 127).
• A computer program sorted through amino acid sequences to pinpoint telltale proteins in troublesome bacteria (May 12, 159: 302).
• A new interpretation of the famous Mesopotamian clay tablet known as Plimpton 322 suggested that it’s a list of examples that a teacher would use to quiz students about squared numbers and their reciprocals (Jan. 27, 159: 56).
• A participant in the Great Internet Mersenne Prime Search found the largest known prime number, which runs to 4,053,946 decimal digits (Dec. 15, 160: 372).

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Paleobiology

• A tiny skull found in 195-million-year-old Chinese sediments indicated that crucial features of mammalian anatomy evolved more than 45 million years earlier than scientists had thought (May 26, 159: 324*).
• Two new dinosaur species found in 90-million-year-old rocks of the American Southwest were the first to fill a 30-million-year gap in the fossil record (June 23, 159: 389*).
• Soft tissue in a 70-million-year-old fossil hinted that some dinosaurs filtered food from water and mud (Sept. 1, 160: 133).
• The discovery of early whale fossils with certain anklebones intact bolstered the notion that whales are closely related to some modern hoofed mammals (Sept. 22, 160: 180*).
• A new analysis of fossils and living animals suggested that most dinosaurs’ nostrils were near the tips of their snouts (Aug. 4, 160: 70).
• Scientists unveiled an 8-ton, 12-meter-long ancient crocodile relative that munched on dinosaurs (Oct. 27, 160: 260*).
• Oleanane, a chemical related to those in modern flowering plants, was found in fossil-bearing sediments. The discovery may help identify flowers’ ancestors (April 21, 159: 253).
• Excavations in Egypt unearthed bones of an 80-ton titanosaur, seemingly the second-most-massive dinosaur known (June 23, 159: 397).
• Fossil charcoal suggests wildfire cycles as long as 360 million years ago (May 19, 159: 309).

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Physics

• Measurements of neutrinos from the sun strengthened a major challenge to the central theory of particle physics (June 23, 159: 388).
• Accelerator experiments detected CP violation—a subtle difference between matter and antimatter—among subatomic particles known as B-mesons (March 3, 159: 143; July 14, 160: 20).
• Light stood still for the first time in the laboratory when photons passing through laser-lit vapors were halted by gas atoms and later re-emitted (Jan. 27, 159: 52*).
• Heavy-element researchers retracted their 1999 claim to having created element 118, which had been the heaviest member of the periodic table (Aug. 4, 160: 68).
• X rays revealed a specific atomic arrangement in piezoelectric crystals that may explain their unusual degree of expansion when they are zapped by an electric field (March 17, 159: 167*).
• Physicists induced a weird correlation, called entanglement, between quantum states of trillions of atoms—a record number—at room temperature (Sept. 29, 160: 196*).
• A simple, readily available material called magnesium diboride was found to conduct electricity without resistance at an unexpectedly high temperature, sparking a surge of research into the compound (March 3, 159: 134*).
• Astrophysicists reported that the strength of the electromagnetic force, supposedly a constant of nature, was once slightly smaller than it is today, which suggests that laws of physics vary over time and space (Oct. 6, 160: 222*).
• A freak accident, which destroyed thousands of sensitive light detectors at the Super-Kamiokande neutrino detector near Tokyo, disrupted experiments there and observations of neutrinos from space (Nov. 24, 160: 327).
• By producing unprecedented numbers of atomic nuclei harboring pairs of exotic lambda particles, physicists verified nature’s preference for combining in twos and threes the fundamental particles that they call quarks. The finding may lead to insight into stellar explosions and neutron stars (Aug. 25, 160: 116*).
• An experiment in which an electron beam probed deep into protons indicated that the distribution of electric charge within the particles may be startlingly different from what scientists have thought for more than 50 years (May 5, 159: 277).
• A close look at copper revealed that atoms constantly roam randomly and widely in the metal’s surface layer rather than stay still, as scientists had previously assumed (Feb. 24, 159: 118).

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Technology

• Researchers made electronic circuits from transistors as small as single molecules to circumvent limits on today’s methods (May 5, 159: 286, May 26, 335; Nov. 10, 160: 294, Dec. 8, 367).
• Doctors tested high-intensity ultrasound devices for incision-free surgery with sound waves (Jan. 6, 159: 12).
• Biology and electronics drew closer as scientists devised ways to grow nerve and liver cells on silicon microchips (April 14, 159: 230; Oct. 6, 160: 216).
• In a step toward widespread microcircuits that are exceptionally fast and manipulate light, a new method of growing crystals induced high-performance semiconductors to adhere to ordinary silicon (Sept. 15, 160: 164*).
• The first transatlantic surgery took place when physicians in New York electronically manipulated a robot in Strasbourg, France, to remove a woman’s gall bladder (Oct. 6, 160: 216).
• Engineers unveiled a self-healing material containing microspheres that release glue when a crack develops (Feb. 17, 159: 101*).
• A gasoline-distilling device for cars captured the most volatile hydrocarbons for use in cold starts and lowered emissions of unburned fuel (Jan. 20, 159: 39*).

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Science News of the Year 2000