Science News of the Year 2007
Compiled by the staff of Science News
Tuning In to Science
In its own way, science is a lot like '60s rock 'n' roll on AM radio. If you're old enough, you remember the slogan: "And the hits just keep on comin'."
With science, the news just keeps on comin'. Somehow, year after year, science never runs out of hit discoveries. From land-based laboratories to the depths of the oceans to remote realms of the cosmos, intrepid investigators find enough novelties in nature each year to fill the pages of thousands of journals and populate the programs of countless conferences.
Condensing the highlights from those discoveries into a few magazine pages isn't as challenging as making the discoveries to begin with, but it is almost as much fun. So Science News staff writers enjoyed poring over the potpourri of science stories from 2007 to select those most worthy of enshrinement in the magazine's annual year-end issue.
There's no point in ranking these stories for impact or importance—that judgment comes only after the ensuing years (or decades) sort the permanent and profound additions to knowledge from false alarms and flashes in pans. But many items are worth mentioning as reminders of how deeply science touches society. Politicians concerned with the problem of violence should note the news about charging juveniles as adults (SN: 4/21/07, p. 243*) and school violence-prevention programs (SN: 9/1/07, p. 133*). Observations of Venus provide insights into its atmosphere that are relevant to understanding the Earth's (SN: 12/1/07, p. 339). Studies of the preservative thimerosal help inform debates over vaccine dangers (SN: 9/29/07, p. 197). Women pondering hormone replacement therapy should be aware of the relevance of age in assessing its implications for heart risks (SN: 4/28/07, p. 270).
Of course, no one of these new studies is the final, or only, word. The very nature of science guarantees future revisions of past findings and occasional overthrows of conventional belief. Making sound social policy requires keeping up with science as it marches along. And that's why pausing to reflect on each year's advances is so worthwhile (besides being so much fun).
—Tom Siegfried, Editor in Chief
Anthropology & Archaeology
Eastern roots A mix of anatomical traits on a 40,000-year-old partial human skeleton unearthed in China supported the controversial possibility of interbreeding among Stone Age Homo species (171: 211).
Early walkers New fossil finds showed that 1.77-million-year-old human ancestors trekked from Africa to Asia using legs, feet, and spines shaped much like ours, although they had small brains and apelike arms (172: 179*).
Pacific trips DNA extracted from a chicken bone found in Chile suggested that Polynesian seafarers brought poultry to South America by about 620 years ago (171: 356*). Other evidence indicated that, roughly 1,000 years ago, Polynesians sailed canoes to Hawaii and back (172: 198).
Chimp hunters Researchers for the first time observed wild chimpanzees, mainly females and youngsters, making and using tools for hunting small animals (171: 131*). An excavation in western Africa revealed that a chimp stone age started at least 4,300 years ago (171: 99*).
Tree walking Field work in Indonesia demonstrated that orangutans at times walk upright much as people do, suggesting that an upright stance evolved in a common ancestor of all living apes (172: 72*).
Tool time Primate and brain-scan studies converged on the notion that human tool use grew out of an evolutionarily ancient neural capacity for manipulating objects (171: 88).
Alien orbs Astronomers found what they are calling Earth's closest known analog outside the solar system, an object with an average temperature that may allow water to be liquid (171: 259*). A newly discovered planet outside the solar system—an exoplanet—appeared to be Neptune-sized and composed mainly of water solidified under high pressure (171: 308*). Researchers for the first time recorded the spectra of radiation emitted by two exoplanets (171: 115*). They also discovered the largest—and lowest-density—exoplanet yet found (172: 174).
Blooming comets Flaunting a majestic tail over southern skies, Comet McNaught became the brightest comet in more than 40 years (171: 52). In late October, Comet 17P/Holmes suddenly burst into brightness and became a naked-eye object for several weeks (172: 309).
Five in one With the discovery of a fifth planet circling the nearby star 55 Cancri, astronomers found the most populous—and heaviest—planetary system beyond the sun's (172: 334).
Death and life An exoplanet survived after its aging parent star ballooned into a red giant that almost engulfed it (172: 163), while infrared observations depicted dusty vestiges of a planetary system dancing around a dead star (171: 100). Material shed by a dying star might give birth to planets, researchers reported (171: 62).
Planetary prelude An infrared portrait of an embryonic, sunlike star revealed an early, crucial step in the process of planet formation (172: 358).
Joe Average A collection of low-mass galaxies, dating from when the universe was just 2 billion years old, appeared to be the typical building blocks of large galaxies like the Milky Way (172:373).
In transit Observations of minieclipses that occur when a distant planet passes in front of its parent star revealed new insights into the size, composition, and temperature of exoplanets (172: 24*).
Distant dustup Some of the best evidence yet emerged for an asteroid belt beyond the solar system (171: 5*).
Smash up Images recorded one of the biggest cosmic collisions known: four galaxies ramming into each other (172: 173).
Pondering plumes The action of Saturn's gravity generates the plumes of water vapor shooting out from cracks on the moon Enceladus (171: 350). The Cassini spacecraft will change course to take a closer look at the plumes next March (172: 110).
Dark riddle Debris from an ancient collision of galaxy clusters seemed to show cosmic dark matter behaving in a puzzling way (172: 117*).
Heavenly chemistry Discovery of a rare, negatively charged organic molecule shed light on conditions in interstellar gas clouds, where amino acids, sugars, and other prebiologic compounds form (172: 54).
In the black A flotilla of X-ray–observing spacecraft homed in on the whirlpool of activity surrounding a supermassive black hole (171:8). A chance eclipse enabled astronomers for the first time to measure the width of a disk of swirling, hot matter around a supermassive black hole (171: 253).
Stellar spectaculars Astronomers reported the two brightest stellar explosions ever observed (171: 293), which could be the first examples of a rare type of supernova involving a freakishly massive star or a single star undergoing multiple outbursts (172: 269).
Passing galaxies The newly measured speeds of two familiar companion galaxies to the Milky Way suggest that they are not gravitationally bound to the Milky Way, but are relative newcomers passing by for the first time (171: 19; 172: 253).
Sun watchers Twin spacecraft began taking three-dimensional images of the sun and for the first time tracked solar storms from their birth in the lower depths of the sun's atmosphere all the way to Earth's orbit (171: 93, 133).
Tilted rings The rings of Uranus, now tilted edge-on to Earth, exhibited never-before-seen structures (172: 157).
Watery Mars Liquid may have percolated through underground rock on the Red Planet, providing a possible habitat for primitive life, suggest images of ancient cracks on Mars (171: 158). An ultrasharp image of part of one Mars crater showed waterborne sediments and volcanic ash (172: 245).
Red ice The global darkening of Mars' surface in recent decades has significantly raised the Red Planet's temperature, a possible cause for the substantial, recent shrinkage of the planet's southern ice cap (171: 214). If the frozen water stored near the south pole of Mars suddenly melted, it would make a planetwide ocean 11 meters deep (171: 206). An immense volume of ice-rich material may underlie a formation that extends about one-quarter of the way around Mars' equator (172: 277).
Ringing portrait NASA's Cassini spacecraft took the most sweeping views ever recorded of Saturn's icy rings (171: 148).
Martian caverns Images taken by a Mars-orbiting spacecraft depicted what appear to be caves on the Red Planet (171: 237).
Kaput The sharpest, most sensitive camera on the aging Hubble Space Telescope stopped working (171: 68).
Dino killer unveiled The asteroid that wiped out the dinosaurs 65 million years ago may have been a wayward fragment from a violent collision in the asteroid belt (172: 148*).
Dwarfing growth Researchers found the smallest galaxy known (171: 62). Another wispy dwarf galaxy, called Leo A, appeared to challenge models of galaxy evolution (171: 195). A small galaxy at the periphery of the giant Andromeda galaxy looked to be a galactic building block of the modern-day universe (171: 357).
Puny Pluto Ex-planet Pluto suffered another demotion, as observations showed that it's much less massive than Eris, another distant denizen of the outer solar system's Kuiper belt (171: 413). Astronomers found the first "extended family" of related objects in the Kuiper belt (171: 164).
Heavy weight The discovery of a stellar-mass black hole almost 16 times as massive as the sun, as well as the possible discovery of an even heavier one, challenged theories of how such black holes form (172: 261).
Match made in heaven Researchers discovered a group of nearby galaxies nearly identical to some of the remotest known, offering a close-up glimpse of the remote era when galaxies first formed (172: 212).
Sunny fate The solar system already lies in the suburbs of the Milky Way, but analyses indicated the sun and its planets will be yanked even farther out in about 5 billion years (171: 365).
Death spin Researchers identified what appears to be the fastest-spinning stellar corpse ever documented (171: 173).
Plenty of nothing Researchers found the largest hole in the universe, a billion light-year-wide region devoid of matter (172: 190).
Violent origins A massive star pummeled our infant solar system, first blasting it with a massive wind, then exploding nearby, driving shock waves into the fledgling system that irrevocably altered its chemistry (171: 323*).
Sunstruck Spacecraft images revealed that a magnetic hurricane from the sun severed a comet's ion tail (172: 228).
Sunny view In Peru, researchers found the oldest known solar observatory in the Americas—a group of 13 towers first used around 300 B.C. to mark the positions of sunrises and sunsets from summer to winter solstice (171: 280).
Satellite dreams The launch of Sputnik 1 half a century ago ushered in a scientific and technological revolution, but dreams of the human conquest of space have stalled (172: 212*).
Killer genes Depressed patients who had inherited certain gene variants displayed an increased tendency to contemplate suicide while taking antidepressant medication, a finding with potential treatment implications (172: 211*).
IQ insight By tracking the development of two groups of children, scientists found that breast-feeding substantially raises IQ scores only for those who inherit a specific gene variant involved in processing mothers' milk (172: 291*).
Compulsive clues Mice bred to lack a gene involved in brain-cell communication developed excessive grooming and other problems that may represent an animal model of obsessive-compulsive disorder (172: 116).
Autistic DNA An international study directed the search for autism-influencing genes to a previously overlooked DNA segment that contains several promising candidate genes (171:117).
Om style Researchers demonstrated that intensive meditation training amplifies control over one's attention and the ability to notice rapidly presented items (171: 291*).
Stem awareness Observations of children born missing much of their brains, combined with animal studies, indicated that the brain stem organizes a basic form of consciousness (172: 170).
Bipolar bulge Scientists reported that rates of bipolar disorder among children and teenagers have dramatically increased since 1994, raising concerns about over-diagnosis of this severe mood disorder (172: 150).
Violent leads A research review concluded that transferring young offenders into the adult-justice system does more harm than good (171: 243*). Another review concluded that various violence-prevention programs in the schools reduce disruptive behavior (172: 133*).
Word shifts Two investigations quantified ways in which frequently used words change slowly over thousands of years while rarely used words rapidly take on new forms, a key mechanism in language evolution (172: 227*).
Forget it Investigators identified brain areas that contribute to the ability to forget disturbing memories on purpose (172: 21).
You again Transference, a psychological process in which a person unconsciously overlays past relationships onto current ones, received renewed scientific attention (171: 363*).
Mother's milk Reversing earlier advice, health authorities now say that babies born to HIV-positive mothers in poor countries have a better chance of avoiding infection if they breast-feed exclusively (172: 187).
Social disease A new test for human papillomavirus (HPV) detected cervical cancer more reliably than traditional Pap smears (172: 243*). Cancer of the throat and tonsils can arise from an HPV infection (171: 291*). The widely used spermicide nonoxynol-9 may boost HPV's infectiousness (172: 6).
Theory debunked Thimerosal, a mercury-containing vaccine preservative, showed no signs of causing memory or attention problems in children (172: 197*).
HIV then and now Analyses of 25-year-old blood samples indicated that HIV reached the United States in about 1969, 12 years before AIDS was first formally described (172: 275*). Three genetic variations picked out by powerful whole-genome scans helped explain why some people develop AIDS quickly while others keep it at bay (172: 35*). HIV can cause dementia by killing mature brain cells and blocking the creation of new ones, data showed (172: 157). A hepatitis B drug spurred resistance to HIV drugs in people infected with both diseases (172: 29), but an antiviral drug commonly taken for genital herpes seemed to suppress HIV in people harboring both pathogens (171: 116).
Cancer biology Survivors of a childhood cancer face a six-fold increased risk of developing a new cancer later in life, one study found (171:157). Four proteins work together to assist cancer growth and metastasis, tests in mice suggested, and drugs against them inhibited both processes (171: 229). Susceptibility to radiation-induced tumors runs in families (171: 307).
Bacterial woes A resistant staphylococcus strain sabotages immune cells' ability to survive, data showed (172: 307). Acinetobacter baumannii, a common bacterium, showed signs of becoming more drug resistant (172: 228*), as did a microbe that causes middle ear infections (172: 301). Honey from New Zealand gums up bacteria, which indicated a potential means of combating difficult-to-treat infections (171: 366).
Shot in the arm An experimental vaccine for hepatitis E proved nearly 96 percent protective in a test in Nepalese soldiers (171: 131). A vaccine for meningitis and pneumonia prevented many childhood ear infections and the complications that they cause (171: 222).
Multiple sclerosis A DNA vaccine against MS passed a safety trial and showed signs of suppressing immune-directed nerve damage in humans (172: 99*). A drug for MS prevented subtle vision loss in many patients (171: 245). Childhood exposure to direct sunshine appeared to protect people against developing MS later (172: 51). A study in mice suggested that small amounts of carbon monoxide might alleviate MS symptoms (171: 53).
Kitty, kitty A nursing home cat in Rhode Island predicts with uncanny accuracy when residents will die, researchers reported (172: 53*). People allergic to dust mites, mold, grass, and other common irritants—but not to cats—still had breathing difficulties when they lived around felines (172: 4).
Surgical advances Drastic weight loss achieved through gastric bypass and other stomach surgeries improved long-term survival in very obese people (172: 115). A new artificial knee ligament that sparks regeneration of natural tissue could eventually make recovering from knee-repair surgery less painful and debilitating (171: 116*).
Cardio risks Many heart disease deaths among firefighters occurred during blazes (171: 180). A common imperfection in the structure of the heart appeared to exacerbate obstructive sleep apnea (171: 218). People who take the diabetes drug rosiglitazone (Avandia) may face an increased risk of heart attack, one study found (171: 397; 172: 164*). Illicit use of methamphetamine could lead to heart problems because the drug alters immune proteins, data show (171: 405).
Eye advance Scientists developed a technique to grow corneal tissue that includes nerve cells, an advance that may enable researchers to test consumer products in lab dishes rather than in live animals (171: 142).
Good to the bone The drug teriparatide inhibited bone loss in people who took medicinal glucocorticoid steroids (172: 309). Older women with osteoporosis who received yearly infusions of a drug that prevents bone loss had far fewer fractures than did peers not getting the drug (171: 275).
Influenza update For the first time, researchers reported drug resistance in type B influenza virus and concluded the drug-resistant strain might jump from person to person (171: 213). Flu shots prevented some deaths and limited hospitalizations for pneumonia in elderly people (172: 213).
Open wide Doctors propped open narrowed arteries in the brain with a tiny mesh cylinder called a stent, similar to the device used in the heart (171: 99). A biodegradable magnesium stent opened clogged blood vessels and then dissolved, circumventing problems linked to permanent metal stents (171: 356). After a meteoric rise, stents coated with drugs to prevent renarrowing of arteries have begun to fall from favor among cardiologists (171: 394).
Breathing easier Heating lung tissue to kill overgrown smooth muscle in airways thwarted asthma (171: 195). Children whose stomachs carry the bacterium Helicobacter pylori faced a decreased risk for asthma (172: 270), but infants who got several courses of antibiotics before their first birthdays proved to be at greater risk later (172: 14).
Odd vectors Fruit bats in Bangladesh regularly trigger small outbreaks of Nipah virus, which causes brain inflammation and death (171: 366).
Toxic intake Smoking before pregnancy may harm the reproductive capacity of female offspring, one study found (172: 326). Attempts to cleanse illicit drugs from the body by taking large doses of niacin caused life-threatening reactions (171: 212). Nanoparticles in diesel fumes thwarted proteins that dissolve blood clots, perhaps increasing the risk of heart attacks (172: 205).
Stopping stroke An experimental procedure that delivers a clot-busting drug directly to the brain triggered a remarkable turnaround in some stroke patients (171: 126). The antibiotic minocycline seemed to limit brain damage in stroke patients (172: 238).
Liver care A slate of treatments, including three established diabetes drugs, appears therapeutic for nonalcoholic fatty liver disease (171: 136).
Tropical scourges The parasitic worm that causes river blindness showed signs of developing resistance to the only drug that controls it (171: 388). Mosquito nets treated with insecticides decreased death rates among children in Kenya (172: 195). Children in Uganda who contract malaria recovered faster with a drug based on artemisinin, derived from Chinese wormwood, than with the standard therapy (171: 381).
Prions Diseases caused by prions, deformed proteins that cause brain-destroying illnesses such as mad cow disease, can be reversed if caught early enough, experiments in mice indicated (171: 68*). Prions proved more infectious when bound to soil particles (172: 36).
Bad to the bone Popular acid-reducing drugs called proton-pump inhibitors appeared to increase the risk of hip fractures in people over 50 (171: 3).
Steady, there Nail-gun injuries among do-it-yourself carpenters have tripled since 1991 (171: 334).
Parkinson's disease Lifelong smoking roughly halves the chance of getting Parkinson's disease, a study showed (172: 20). Transplants of human brain stem cells triggered signs of improvement in monkeys with a Parkinson's-like disorder (172: 45).
I got rhythm Sildenafil (Viagra) helped laboratory rodents recover from circadian disruptions similar to jet lag (171: 324).
Bad inheritance A heightened risk of brain aneurysm seemed to be passed down in some families, and the life-threatening rupture of an aneurysm appeared to strike earlier in a succeeding generation (171: 126).
Botany & Zoology
Big changes The Intergovernmental Panel on Climate Change reported biological evidence for global warming has grown substantially since the 2001 assessment (171: 378*). In a rare study of how ocean acidification could affect animal behavior, a shoreline snail was shown to lose its defenses against crabs (172: 245).
Bad news bears Climate and population models predicted Arctic ice will soon melt so drastically during summers that two-thirds of polar bears will disappear by mid-century. Other species will feel the disruption too (172: 346*; 172: 37).
Wet frontier The Census of Marine Life, a 10-year project to explore vast regions of the oceans, found weird new species and unexpected diversity in deep waters and the polar oceans (171: 107; 171: 308).
Green trees Two major analyses of genes from chloroplasts agreed on the basic shape of the family tree for flowering plants (172: 366). Obscure plants long thought to be relatives of grasses represent one of the most ancient surviving lineages of flowering plants (171: 205).
Virus toll Population declines in five common birds, including robins and bluebirds, were linked to West Nile virus (171: 413).
Bee collapse Many U.S. worker honeybees mysteriously vanished (172: 56*). The little-known Israeli acute paralysis virus was linked to the collapse as a cause or a marker (172: 147*).
Cousins Gliding mammals called colugos, which aren't quite primates, showed up in a genetic analysis as primates' nearest kin (172: 275).
Urban life Loud background noise eroded mate fidelity in zebra finches (172:116).
Smells funny Just an hour's swim in slightly contaminated water gave fish such bad body odor that former schoolmates shunned them (172: 262).
Tough bluebirds As western bluebirds recolonize Montana, aggressive males move in first to push out rival species—an unusual example of behavior influencing animal distribution (172: 222).
Hey, bro A little beach plant recognized its siblings as long as their roots grew in nearby soil (171: 372).
Musical shield The clicking sounds of moths dodging bats revealed what could be the first evidence of acoustic mimicry as a defense against predators (171: 397).
Sex again Some beetle mites may be the first animal lineage to have abandoned sexual reproduction and then redeveloped it (171: 302).
Fish switch Salmon implanted with trout reproductive tissue—a new aquaculture technique—bred and produced a generation of normal rainbow trout (172: 164).
Cell & Molecular Biology
Stem cells from skin Two groups of scientists converted people's skin cells directly into stem cells without creating or destroying embryos (172: 323*), an accomplishment built on similar feats performed with mouse cells (172: 29).
Beyond genes Detailed explorations of the human genome showed that individual genes can have complex structures, and that much of what had been called junk DNA is anything but (172: 154*).
Capricious evolution Reconstruction of an ancient protein showed how random, seemingly unimportant mutations set the stage for later genetic changes that gave the protein its modern function (172: 101).
Genome swap Transplanting the entire genome of one species of bacteria into another paved the way for making microbes with synthetic DNA (171: 403*).
Longevity lessons People on reduced-calorie diets experienced many of the same cellular changes as did long-lived animals on such diets (171: 147*). Nerves in the brain proved crucial to the life-extending effect of calorie-restricted diets, experiments with roundworms showed (171: 414). Mice lived longer when they were fooled into sensing lower insulin levels than they actually had (172: 62). In insects, the scent of food alone actually diminished the longevity advantage of low-calorie diets (171: 94).
Nerve renewal The brain constantly sprouts new neurons, a recently discovered phenomenon that neuroscientists and drug makers began working to understand and exploit (171: 376).
Mapping genomes For the first time, one man's genome, including both sets of chromosomes, was decoded (172: 147). Thirty-five labs unveiled a draft of the genome of the rhesus macaque, the most widely used laboratory primate (171: 237*).
Bacterial inheritance Bacteria exchange genes all the time, but data indicated that they can donate their DNA to some animals as well (172: 131*).
Early evolution The surprisingly complex genome of the starlet sea anemone, a creature with ancient evolutionary roots, showed that animals became genetically robust much earlier than scientists had thought (172: 30).
Amniotic stem cells Scientists discovered that about 1 percent of the cells that float in the fluid that bathes fetuses are stem cells with traits of both embryonic and adult stem cells (171: 30).
On the cheap Methods under development could make DNA sequencing quicker and less expensive, a study found, paving the way for the day when treatments can be tailored to each person's genetic profile (171: 235).
Cell factories Scientists found a master gene that allows tissue-regenerating stem cells to retain their regenerative capacity (171: 292). Certain adult stem cells from female mice regenerated better than those from males, indicating that not all adult stem cells are created equal (171: 228).
Bossy bones A protein made by bone cells had a surprising influence on energy metabolism, and could have a role in treating diabetes (172: 83*).
Chickengineering Genetically engineered hens can not only produce useful drugs in their eggs but also reliably pass on this characteristic to new generations of offspring (171: 35*).
Mistaken identity Embryonic stem cells claimed by discredited Korean researcher Woo Suk Hwang to have come from cloned human embryos actually came from embryos that grew from unfertilized eggs (172: 69).
Crossing the line With the help of a molecule from the rabies virus, scientists selectively ferried a drug across the blood-brain barrier to treat a neurological disease in mice (171: 387*).
Live wire Nerve axons are not simply passive carriers of electrical signals in the brain, as scientists had thought, but proved influential in how neurons fire (172: 148).
Bio-computer Artificial genes inserted into cells produced RNA—molecules that carry genetic information within the cell—that performed logical computations (171: 413).
Radiation diet The pigment melanin may enable certain fungi to convert dangerous radiation into usable energy (171: 325*).
Stowaways The trillions of microbes that live in the human gut and on the skin may be essential to health (171: 314*).
Microbe memory Amoebas appeared to possess a rudimentary form of memory that keeps them from walking around in circles (171: 205).
Space bugs Bacteria that flew on a space shuttle became more virulent than their Earthbound counterparts (172: 197).
Primitive immunity In social amoebas, sluglike clusters of usually independent organisms, certain cells take on a protective role, a finding that hinted at the origin of immune systems in higher animals (172: 125).
CSI Africa Scientists tracked the origin of an illegal ivory shipment to Zambia by using an improved DNA-analysis technique to study the confiscated tusks (171: 158).
Beyond petroleum A faster, simpler manufacturing technique showed promise for making a synthetic biofuel into an even stronger competitor to ethanol (171: 389*). Also, a new chemical process held out the potential that many products now manufactured from petroleum could one day be made from sugar molecules (171: 120*).
1,001 tiny uses? Nanoparticles of magnetite have catalytic properties that may be useful in wastewater treatment and biomedical assays (172: 174). Small clusters of drug molecules attached to nanoparticles of gold appeared capable of delivering a safer and more effective chemotherapy punch to tumors (172: 180). Gluing together nanoscale clay particles with a simple adhesive created a strong but flexible material (172: 254).
Passing through A new polymer membrane efficiently separated carbon dioxide from methane and could greatly ease the processing of natural gas (172: 269).
Black and white Layers of microscopic filaments sprayed onto a surface prevented it from reflecting light, a potentially useful trait for technologies from solar cells to fiber-optic communications (171: 132). At the other extreme, scales covering the Cyphochilus beetle offered researchers a model for microstructures that could make a variety of surfaces whiter and brighter (171: 78).
Shocking films Ultrathin sheets made of cellulose and carbon nanotubes served as flexible, versatile batteries (172: 100).
Magnet makeover A new family of hybrid magnets debuted as a first step toward organic versions of the familiar metal objects (171: 77).
Crystal matchmaker Nonperiodic structures called quasicrystals acted as interfaces between crystal structures that ordinarily would not stick to each other (172: 46).
No sweat A new, breathable fabric, envisioned for use in comfortable protective gear, proved impervious to chemical-warfare agents (171: 13).
Heal thyself A self-repairing composite material repeatedly healed damage at the same spot (171: 398).
Got mussel? A new, adhesive that borrowed tricks from the gecko and the mussel stuck and detached repeatedly—even when wet (172: 78).
Sop story A new, porous gel efficiently removes mercury from contaminated water and might find use in catalyzing chemical reactions, such as those that generate hydrogen for fuel (172: 52).
Sensing soot A chemical in urine revealed a person's exposure to diesel exhaust (172: 69).
Pin the blame With a 90 percent certainty, the Intergovernmental Panel on Climate Change linked last century's rise in global average temperature to rising concentrations of heat-trapping greenhouse gases (171: 83).
Hot times On the heels of the continental United States' warmest year on record in 2006 (171: 46), sea ice in the Arctic Ocean in September 2007 fell to a modern-day low (172: 238). Satellite observations indicated that Arctic regions reflected less sunlight into space in the summer of 2006 than in other recent years, a change that might exacerbate warming of Earth's climate (171: 382).
Young and restless The oldest rocks in the world, found in Greenland, showed that Earth's shifting crust began its tectonic movements at least 3.8 billion years ago (171: 179*).
Oxygen rocks A dramatic rise in the concentration of oxygen in Earth's atmosphere resulted from a change in volcanic activity about 2.5 billion years ago (172: 132).
Getting warmer A long-term decrease in Lake Superior's winter ice cover has caused the lake's surface waters to warm faster than air temperatures at nearby sites onshore, scientists said (171: 286).
Reach deep In a remote part of the southeastern Pacific where marine life is sparse, ultraviolet light penetrates to unprecedented depths, research showed (172: 77).
Killer clay A certain type of French clay smothers a diverse array of bacteria, offering a treatment for antibiotic-resistant strains and a nasty pathogen that causes skin ulcers (172: 276*).
Lake-bottom bounty Surprisingly, sediments in a few lakes in northeastern Canada were not scoured away during recent ice ages, a discovery that might aid climate researchers (172: 211).
Climate sensors Scientists developed a way to use corn plants to monitor and map modern human-generated emissions of carbon dioxide (171: 93). Meanwhile, other teams worked to discern past climates by analyzing harvest dates of grapes in Switzerland (172: 318) and gases trapped in lumps of glass formed when lightning struck sandy ground (171: 101*).
Flotsam science Researchers harnessed the power of floating items as diverse as tennis shoes, tub toys, and hockey gloves to chart the path and speed of currents in the North Pacific Ocean (171: 267*).
Stunting growth Rising concentrations of ground-level ozone due to pollution will stifle the growth of vegetation in many regions, accelerating the buildup of planet-warming carbon dioxide in the atmosphere, researchers concluded (172: 52*).
A smashing end? Field studies across North America indicated that an extraterrestrial object exploded above Canada about 12,900 years ago, sparking devastating wildfires and triggering a millennium-long cold spell at the end of the last ice age (171: 339*).
No fooling Lofting tiny particles high into the atmosphere to counteract global warming could provoke extended droughts and other weather disruptions, scientists theorized (172: 125).
Mixed results Using groundwater to irrigate crops adds planet-warming carbon dioxide to the atmosphere (172: 301), research indicated, but the cooling effect created by such irrigation can significantly alter local climate and mask effects of global warming (171: 174).
Withering weather When southern Europe receives scant rainfall in the winter, the whole continent tends to bake the following summer, a new analysis found (171: 269).
Environment & Ecology
Plastic concerns Early exposure to bisphenol A, a chemical building block of clear plastics, can trigger a variety of later health problems, two new studies showed (172: 84*). Later, large review panels concluded that existing animal data suggest this dietary pollutant might cause myriad adverse human-health effects at doses comparable to those people now encounter (172: 202).
Heavy impact Demands of the world's population as a whole consume nearly a quarter of Earth's total biological productivity, an analysis found (172: 235*).
Aquatic non-scents Many common pollutants were found to jeopardize the survival of fish and other aquatic species by blunting their sense of smell (171: 59*).
Counterintuitive toxicity Standard high-dose testing of poisons frequently fails to predict potentially important impacts—either risks or benefits—of very low-dose exposures (171: 40*).
Tadpole stalker A mysterious protozoan disease was discovered to be triggering mass die-offs of frog tadpoles throughout much of the United States (172: 325*).
Great-gram's fault Pollutant exposures in rodents triggered behavioral changes that persisted generation after generation (171: 198).
Policing fisheries Congress reauthorized and strengthened a 30-year-old federal law governing fishing and ocean management (171: 30).
Herbal herbicides Scientists have begun tapping plants and the self-defense chemicals they make for new weed killers, many of which may find use in organic farming (171: 167).
Nonstick releases Nonstick coatings on fry pans and microwave-popcorn bags can, when heated, release traces of potentially toxic perfluorinated chemicals (171: 61).
Mercury magnets Certain areas of North America proved particularly susceptible to environmental accumulation of mercury (171: 45).
Sooty triggers Nanoparticles in diesel exhaust activated genes that worsen cholesterol's damaging effects (172: 93). Small blood vessels in rodents lost the ability to precisely regulate blood flow after exposure to an oily constituent of diesel soot, but effects varied greatly by age and gender (171: 381).
Ethanol conundrums Strong expansion of the U.S. corn-to-ethanol industry could soon divert more than half of U.S. corn yields from food into transportation fuel (171: 78). An alternative cellulose-based ethanol could help lower greenhouse-gas emissions, some research showed, but the technologies required are far from straightforward (172: 120).
Suffocating impacts Seasonal oxygen shortages in coastal waters, increasing in severity because of pollution, were shown to impair fish reproduction (172: 158).
Asbestos, really Federal mineralogists corroborated earlier evidence that foothill communities around Sacramento, Calif., lay atop soils laced with asbestos (171: 29).
Rocky fallout New research explained why a carcinogenic form of chromium has been turning up in ground and surface waters far from industrial sources (171: 254).
Belittling pollution Pregnant women exposed even to moderate amounts of several common air pollutants tend to have babies with low birthweights (171: 261).
E-hazards The dismantling and recycling of electronic devices was linked with high concentrations of flame retardants in the blood of Chinese residents—even those living 50 kilometers away (172: 20*).
Polluted cats An epidemic of hyperthyroidism in house cats was linked with environmental exposures to certain flame retardants (172: 125).
Toxic similarities At concentrations found in the environment, three dissimilar toxic agents each seized control of a signaling pathway that regulates developing brain cells (171: 134).
Dirty printers Some laser printers emitted substantial amounts of potentially hazardous nanoscale indoor-air pollution (172: 158).
Nanorisks Making carbon nanotubes also produced lots of airborne carcinogens (172: 142).
Food & Nutrition
Supersized livers A diet of sweet and high-fat foods rapidly and dangerously fattened the livers of rodents (sciencenews.org/articles/20070609/food.asp). Another rodent study narrowed this link to overconsumption of the rapidly digesting carbohydrates typical of breads, fries, and sweets (sciencenews.org/articles/20070929/food.asp). But tricking the body into storing excess calories in fat cells—not the liver—disconnected the link between overeating and fatty liver disease (sciencenews.org/articles/20071006/food.asp).
Redefining nutritious Among children prone to diabetes, those who consumed the most omega-3 fatty acids showed the lowest incidence of disease (172: 237). Moderate consumption of beer, wine, or gin lowered blood glucose, suggesting alcohol may help stave off type 2 diabetes (171: 405).
D benefits and risk To prevent rickets, a Canadian medical society recommended pregnant women and nursing moms dramatically boost their intake of vitamin D (sciencenews.org/articles/20071117/food.asp). Two new studies offered evidence of an additional benefit: a diminished risk of asthma when babies get ample vitamin D (sciencenews.org/articles/20070519/food.asp). However, plenty of this vitamin will increase a child's uptake of any lead in the environment (sciencenews.org/articles/20070512/food.asp).
Cocoa flow A chocolate drink that retains natural ingredients, ones normally removed to improve cocoa's flavor, boosted blood flow to the brain (171: 142).
Weighty matters Among mice, being either over- or undernourished before birth altered gene activity that fosters obesity in adulthood (171: 115).
Meaty hormone Overcooked meat forms chemicals that mimic a female sex hormone, which offered a "biologically plausible" explanation for why breast cancer risk has been linked to red-meat intake (sciencenews.org/articles/20071020/food.asp).
Java fiber Coffee was identified as a significant source of dietary fiber (171: 125).
Wrong formula Low-birthweight babies fed catch-up formulas rich in calories had significantly higher blood pressure by age 8 than did kids given regular formula (sciencenews.org/articles/ 20070217/food. asp).
Finding focus An amino acid in tea combines with the brew's caffeine to enliven brain cells that aid concentration (172: 206).
Pee for produce A study with cabbage demonstrated that human urine can outperform conventional fertilizer (172: 222).
Buzzing kids Common food colorings and a common preservative increased a child's risk of exhibiting hyperactivity and inattentiveness (172: 349).
Smart pills A dietary supplement combo boosted older adults' performance on simple mental tests (171: 301).
Green rescue A constituent of green tea appeared capable of rescuing brain cells damaged in Parkinson's disease (172: 206).
Fighting malaria An herbal-tea remedy for malaria contains a component that showed potential as the basis for a novel drug against the disease (171: 77).
A diet for noise Consuming certain dietary supplements before encountering a dangerous din can limit or eliminate noise-induced hearing loss, animal data showed (sciencenews.org/food/articles/20070421/food.asp).
Challenged improvement A controversial trial of interesterified fat—a chemically modified fat—suggested it was more harmful than a partially hydrogenated vegetable oil rich in trans fat (171: 84).
Infectious pâté Fatty goose liver contains amyloid that triggered amyloid brain disease when fed in large quantity to mice (sciencenews.org/articles/20070630/food.asp).
Nutrient puzzle The more calcium and vitamin D that elderly individuals consumed, the greater the number and size of lesions that showed up in their brains (171: 381).
Never mind The herbal supplement black cohosh proved no more effective than a placebo in reducing hot flashes in menopausal women, contradicting earlier claims (171: 29).
Oolong slim Rats absorbed less dietary fat and gained less weight when their diets contained lots of oolong tea (171: 318).
Thoughtful brews Caffeinated coffee and tea appeared to keep aging wits sharp—but only in women (sciencenews.org/articles/20070818/food.asp).
Bad time to drink Regular alcohol consumption during pregnancy tripled the chance that any son would be born with undescended testes, a risk factor for male infertility (sciencenews.org/articles/20070106/food.asp).
Mathematics & Computers
Second lab Epidemiologists and social scientists tapped into virtual online worlds such as Second Life to collect data with real-world uses (172: 264).
Good epidemics An analysis of global exports showed that a country's competitive edge can spread industry to industry, like rumors or diseases, offering an explanation for why some developing economies seem condemned to depend on a handful of products (172: 138*).
His last theorem Mathematicians reconstructed part of Srinivasan Ramanujan's lost work, which offered pattern-connecting formulas—called mock theta functions—that crop up in different branches of science (171: 149*).
No prison, no dilemma In games that would normally favor cheaters, making participation voluntary can instead promote cooperation, researchers showed (sciencenews.org/articles/20070714/mathtrek.asp).
Separate is never equal Segregation leads automatically to economic inequality, even in the absence of significant discrimination, a mathematical model showed (sciencenews.org/articles/20070915/mathtrek.asp).
Growth formulas Golden angles and other mathematical patterns revealed how plants develop structures with intriguingly elegant geometries (172: 42).
Checkers solved Thanks to an immense calculation that worked out every possible game position, computers learned how to play a flawless game of checkers and force a draw every time (172: 36*).
Internet tentacles A study of the flow of digital information around the world revealed that the Internet's structure resembles that of a medusa jellyfish (171: 387).
Cloudy crystal balls Models may never predict climate accurately, no matter how fast computers get, because subtle uncertainties in the models—rather than in the data themselves—may prove inherently unavoidable, researchers concluded (sciencenews.org/articles/20070804/mathtrek.asp).
Fractal or fake? Algorithms that look for fractal patterns to establish the authenticity of paintings provoked controversy among scientists (171: 122*).
Ancient extract Analyses of a Tyrannosaurus rex leg bone revealed substantial remnants of proteins, a find that strengthens the purported link between modern birds and dinosaurs (171: 228).
Gone under A new analysis of Australian fossils bolstered the notion that humanity's arrival on the island continent led to the extinction of many large creatures there about 50,000 years ago (171: 38*).
Digging the scene Dinosaur remains fossilized within an ancient burrow were the first indisputable evidence that some dinosaurs maintained an underground lifestyle (172: 259*).
Caught in the act Paleontologists unearthed fossils providing direct evidence of something scientists had long suspected: Tiny bones in the middle ears of modern-day mammals evolved from bones located at the rear of their reptilian ancestors' jaws (171: 190).
Slow rise Early dinosaurs didn't quickly eclipse the creatures they evolved from, but lived alongside them for perhaps 20 million years (172: 78).
Pre-Wright flight A meter-long dinosaur swooped from tree to tree using the same arrangement of wings as the Wright brothers' biplane, a new study indicated (171: 53*).
The oldest matrushka? A fossil preserved the remains of one creature inside another that lay nestled inside yet another, which offered the first direct evidence of a three-level food chain of aquatic vertebrates (172: 286).
Unexpected archive Hair from ancient mammoths contained enough genetic material to permit reconstruction of parts of the animal's genome (172: 195*).
Quick bite Saber-toothed cats living in North America around 10,000 years ago had a much weaker bite than modern big cats, analyses suggested (172: 213*).
Einstein unruffled Thirty-five years of laser-tracking a mirror on the moon confirmed that the laws of gravity are the same in all frames of reference, a cornerstone of Einstein's general relativity (172: 324). But technical glitches forced an even longer-running project—a probe NASA began developing in the early 1960s—to delay confirmation of its preliminary data on another general-relativity prediction: that Earth's spin drags the fabric of space around it (171: 270).
Antimatter matter Physicists showed that positronium "atoms," consisting of an electron and a positron (the electron's antimatter counterpart), could bind together briefly to form positronium molecules. The technique used could lead to gamma-ray lasers (172: 163*).
Imaging biomolecules Physicists demonstrated techniques that may enable a new generation of lasers to decode the structure of single biomolecules in motion, rather than in static crystalline form (171: 253; 172:86).
Critical steps The onset of panic in a dense crowd resembles the onset of turbulence in a fluid, videotapes from a Muslim pilgrimage site showed, helping physicists advise Saudi authorities on how to prevent stampedes (171; 213*).
Getting no axion Experiments contradicted earlier evidence suggesting the existence of the axion, a possible constituent of cosmic dark matter (172: 245*).
Broadband vision Physicists showed that specialized, cone-shaped cells efficiently transport light to the back of the retina by acting like optical fibers (171: 317).
Still baffling An experiment failed to confirm the existence of a strange elementary particle called the sterile neutrino, but the new data still potentially contradict current physics theories (171: 254).
Knots everywhere Data showed that a tumbled rope will form surprisingly complicated knots, surprisingly often (172: 398).
Who ordered that? In experiments that created the heaviest isotope of magnesium yet, an unexpected isotope of aluminum also showed up; both types of matter may exist in the crusts of neutron stars (172: 260*).
Within reach An old particle accelerator at the Fermi National Accelerator Laboratory in Illinois might discover a crucial elementary particle before Europe's forthcoming Large Hadron Collider does, scientists reported (171: 270).
Not much latitude A physicist proposed testing a controversial gravitational theory with an experiment that can be done only at a precise time of the year and at exactly 79°50' N, 56° W (171: 206).
Solar processor The wavelike behavior of energy in chlorophyll showed that plants channel solar energy in a way that resembles how a quantum computer would process information (171: 229).
Science & Society
Better yardsticks A federal survey concluded that a lack of measurement tools is jeopardizing the United States' innovative edge (171: 251).
Extreme encyclopedia A consortium of museums and laboratories unveiled plans for a free, Web-based Encyclopedia of Life, which plans to eventually offer an entry for every living species (171: 294).
Hot jobs Workers in the United States toil longer than their counterparts in most other places, leading to dramatically higher U.S. energy and climate-warming costs per employee (171: 13).
NIH stagflation Stationary funding for the National Institutes of Health, in the face of rising costs, has forced many scientists to downsize their labs and abandon some of their most promising work (171: 206).
Inhumane deaths Prisoners given lethal injections may be conscious and experience pain and burning sensations while they asphyxiate (171: 302).
Summing up benefits Taking more math in high school improved students' college grades in physics, chemistry, and biology (172: 78).
Citizen astronomers Scientists recruited online help from the public to classify the shapes of 1 million galaxies in never-before-viewed photographs (172: 62).
Smokin' media White adolescents who frequently watch television and R-rated movies were more likely to try smoking than were peers less exposed to these media (171: 149).
Graphene is forever For the first time, physicists carved transistors out of carbon layers one atom thick and tougher than diamond, creating strong contenders for replacing silicon in future computer chips (172: 200*).
Wireless recharger Scientists transferred power wirelessly across a room using oscillating magnetic fields, opening the possibility of recharging laptops and other gadgets without plugging them in (172: 40*).
Hybrid advancements New metal alloys and nanoparticles increased the efficiency of the platinum catalyst in fuel cells (171: 21). A new type of fuel cell did away with platinum altogether—replacing it with far cheaper metals—and runs on a liquid hydrogen-based fuel that would be easier to distribute and store than pure hydrogen (172: 253).
Power on the fly Engineers packed the most energy yet into a high-speed, lightweight flywheel, which could make electric trains run 15 percent more efficiently or replace batteries in hybrid vehicles (171: 312).
Biowarfare Scientists engineered viruses to penetrate and dissolve bacterial colonies known as biofilms (171: 404).
Spot on A technique for printing dots just 250 nanometers wide—nearly 100 times smaller than dots made by ink-jet printers—offered to ease the production of flexible electronics such as plastic displays and solar cells (172: 166).
Transferred touch Engineers improved amputees' control of prosthetic limbs by rerouting nerves from limbs to muscles in the chest (171: 85*).
Bio DJ Ordinary CD players were adapted to perform chemical assays and potentially to offer medical diagnoses (172: 253).
Crystal clear A scientist grew orderly arrays of nanowires on a crystal, a technique that could lead to high-density memory chips and transparent LEDs (172: 334).
Traffic light Engineers carved chains of microscopic silicon ridges to delay and temporarily store light signals, a step toward computers that process data using photons instead of electrons (171: 3).
Right dosage Physicists built a pipette that dispenses a billionth of a trillionth of a liter at a time—droplets a thousand times as small as previously achieved (171: 244*).
Tractor beam Chemists created nanoparticles that selectively bind to targeted bacteria and drag them toward a magnet—a step toward decontamination of water supplies or bacterial sorting and identification (172: 366).
Beyond retouching New technologies allowed photographers to relight and even refocus scenes after shooting (171: 216*).
On second thought ... A company started selling easy-to-remove tattoo inks—pigment-filled nanoparticles that can be selectively destroyed by the right wavelength of light (172: 232).
Atomic landscapes An electron microscope not only imaged single atoms but also mapped the locations of different chemical elements in a sample (172: 110).
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