Woolly rhinos came down from the cold

Ice Age icons were pre-adapted to harsh climate, new fossils suggestWeb edition : Thursday, September 1st, 2011 COOL RHINOFossils of a new species of woolly rhino, shown here in an artist's reconstruction, have turned up in pre–Ice Age deposits high in the foothills of the Himalayas.Julie Naylor

A new trove of mammal fossils found high in the foothills of the Himalayas suggests that Tibet may have been a harsh, cold testing ground where woolly rhinos and other big mammals developed their cold-climate cool well before the Ice Age began.

Among the treasures from the Zanda Basin is the oldest fossil yet found of a woolly rhino, dating from about 3.7 million years ago, says vertebrate paleontologist Xiaoming Wang from the Natural History Museum of Los Angeles County. The complete skull and several neck vertebrae of the now extinct animal represent a new species, Coelodonta thibetana, Wang and his colleagues report in the Sept. 2 Science.

“It’s an important find,” says vertebrate paleontologist Donald R. Prothero of Occidental College in Los Angeles, who studies the evolution of mammals, including woolly rhinos. The paper is the first evidence for the idea that the lineage of the iconic Ice Age giant, and maybe other species, had already evolved cold-weather adaptations instead of developing them as the big chill set in 2.8 million years ago.

HIGH-ALTITUDE FINDSPaleontologists working in Tibet discovered the skull and lower jaw, shown here in a digital composite, of an ancient species of woolly rhino, Coelodonta thibetana.Image courtesy of Xiaoming Wang

When the Ice Age did come, descendants of the early Tibetan rhinos could have moved gradually off the plateau to lower altitudes throughout Eurasia. Wang and his colleagues note that fossil locations of three later woolly rhino species fit the pattern of a lineage that diversified down and out of the high plateau. “Tibet as a special environment probably is the cradle of some of the cold-adapted species of the Ice Age,” Wang concludes.

That’s a reasonable scenario, Prothero says. “I don’t think it’s been suggested before because there was no evidence for it.”

Wang and his colleagues found such evidence in the Zanda Basin, which sits 3,700 to 4,500 meters above sea level and is surrounded by even higher peaks. “It’s like working on top of Mount Whitney,” the highest peak in the contiguous United States, Wang says.

Toward the end of the field season in August 2007, Wang himself was exploring late in the afternoon a few miles from his colleagues when he stumbled onto a big piece of fossilized bone. Recognizing it as a vertebra, he swung his hammer at a promising spot — and uncovered a hint of what he calls the biggest discovery of his career. “Here is a tooth of a woolly rhino revealed by one single whack of my hammer,” he remembers.

Subtle characteristics identified the skull as a more ancestral species than later, Ice Age woolly rhinos. The Tibetan rhino already had such adaptations as a forward-leaning, flattened horn convenient for sweeping aside snow while foraging for food. The research team estimates the skull came from a mid-sized rhino about the size of today’s Indian and black rhinos. The fossils did not include hair, so paleontologists can only speculate about how woolly it might have been.

In addition to the newly named C. thibetana, the basin has also revealed other cold-adapted mammals whose descendants might have spread during the Ice Age, such as blue sheep and the Tibetan wild ass.

Some Ice Age mammals “probably came from high elevations and were pre-adapted to cold, but I wouldn’t want to say everything followed this pattern,” Prothero cautions. “In the real world nature is always more complex.”

Found in: Life

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Fighting flames with greener materials

New flame retardants rely on alternating nanolayers of relatively nontoxic materialsWeb edition : Wednesday, August 31st, 2011 FOAMING BUBBLESAn electron micrograph shows cotton fabric coated with 20 paired layers of chemicals before (left column) and after (right column) burning. Bubbles in the lower right photo show the coating’s heat-triggered foaming.Y.-C. Li et al/Advanced Materials 2011/Wiley-VCH Verlag

Materials scientists in Texas have developed flexible coatings mere billionths of a meter thick that keep cotton clothing from going up in flames and plastic foam from melting. Unlike the widely used but potentially toxic flame retardants they've been designed to replace, these nano-coatings appear relatively safe, their designers say.

Yu-Chin Li and Jaime Grunlan of Texas A&M University in College Station described their team’s new technologies August 31 at the American Chemical Society national meeting in Denver.

Because fabric fibers are so thin, “being able to fire-retard them is a big deal,” observes chemist Charles Wilkie of Marquette University in Milwaukee, a fire-retardant specialist not involved with the new work. “So I’m encouraged. The new work is impressive.”

Grunlan’s team has been seeking safer alternatives to brominated fire retardants, some of which have been banned over concerns about their potential toxic effects. The researchers’ initial prototypes consisted of alternating layers of garden variety clay and a commercial polymer. But the polymer, a synthetic chemical, did not rely on renewable, green constituents. So the engineers swapped it out for an inexpensive waste material: chitosan, a natural compound extracted from shrimp and lobster shells.

Like the earlier clay-based recipes the group had worked with, the new formulation proved disappointing on cotton fabric, Grunlan says. But it was a game changer for plastic foam, such as the type used as cushioning in furniture. Untreated foam held over a propane torch flame for 10 seconds quickly ignited, melted and burned up. But after applying 10 dual layers of clay and chitosan to an identical piece of foam, the 10-second flame created a thin veneer of char but left the interior unscathed.

Still intent on finding fabric protectants, the team turned to materials that intumesce — undergo a foaming chemical reaction — at high temperatures. In the construction industry, millimeter-thick intumescent coatings on steel girders protect a skyscraper’s skeleton. Grunlan’s group scaled the technology down to nanometer-thick alternating layers of the compounds, polysodium phosphate and poly-allylamine. 

When cotton fabric treated with 10 alternating layers of each chemical was exposed to a flame for 10 seconds, the fabric charred but didn’t burn up, Grunlan says. The only sign of damage was localized, minor charring where the flame touched the fabric. Li, Grunlan and colleagues published details of these experiments online July 29 in Advanced Materials.

These data “sound really good,” Wilkie says — if the concern is preventing ignition of flammable materials. But in the real world, fires last considerably longer than 10 seconds, he points out, so these materials might retard burning or limit its spread, but wouldn’t withstand an inferno.

Vince Baranauskas of NanoSonic Inc. in Pembroke, Va., a firm that engineers materials including fire retardants, cautions that nano-layered flame retardants may not be feasible on a commercial scale. “Alternating dips would cost a great deal more than the fabric itself,” he says.

But Serge Bourbigot of the University of Lille in Villeneuve d'Ascq, France, remains optimistic. The new nanolayer fire retardants — with or without intumescence — are novel and show great potential, he says, even if they might need refinements before they are marketed.

Found in: Environment, Molecules and Technology

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News in Brief: Body & Brain

One defense against diarrhea and early hints of diabetes in obese children in this week’s newsWeb edition : Wednesday, August 31st, 2011

Body’s diarrhea defense
The body has a biological mechanism tailor-made to fend off infections by Clostridium difficile, a bacterium responsible for many hospital-acquired diarrheal infections. Reporting online August 21 in Nature Medicine, researchers at Case Western Reserve University and colleagues from other institutions show that a compound called S-nitrosoglutathione can bind to toxins secreted by the microbe and neutralize them before they damage cells. Increased levels of S-nitrosoglutathione in the guts of mice protected them from C. difficile, the researchers report. —Nathan Seppa

Third graders en route to adult disease
Obese but apparently healthy children 7 to 9 years old were twice as likely to be insulin resistant (a hallmark of impending diabetes) as were normal weight children their age, a team of scientists from U.S. universities finds. The scientists compared a range of features characterizing the blood, vascular health and fat-processing in 123 children. A whole host of prediabetes and pre-heart disease changes were evident in the obese youngsters. These children also were beginning to store fat outside of normal sites, the researchers report online August 25 in Obesity. The results “highlight the importance of interventions to prevent and manage obesity” very early in life. —Janet Raloff

Found in: Body & Brain

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Obesity can turn body fat toxic

A lucky few escape the link with disease-causing inflammation, two studies findWeb edition : Friday, September 2nd, 2011

Obesity can trigger inflammation in the fat cells found just below the skin, creating an environment that has been linked with the development of both diabetes and heart disease, two new studies indicate.

The findings suggest that people need to worry about all types of body fat, not just the deeply embedded fat that earlier work had focused on. But the new work also hints that some face a higher risk than others.

In the body, most fat clusters under the skin in what’s known as subcutaneous adipose tissue. Much of the rest, called visceral fat, accumulates within muscle and between organs deeper inside the body. For more than a decade, studies have shown that obesity triggers visceral fat to begin spewing hormonelike chemicals called cytokines. These proinflammatory chemicals have been linked with metabolic syndrome, a constellation of abnormalities that can include impaired insulin sensitivity (known as insulin resistance), fat buildup around the waist, high blood pressure and low concentrations of HDL, the good cholesterol.

“There’s been this sort of ill-proven idea that subcutaneous adipose tissue is not harmful and that visceral adipose tissue is the vicious demon that makes us sick,” says Gökhan S. Hotamisligil of the Harvard School of Public Health in Boston, who was not involved in the studies. The new data, he says, reinforce the fact that subcutaneous fat is far from benign.

In one study, Ishwarlal Jialal of the University of California, Davis Medical Center in Sacramento and his colleagues sampled blood and subcutaneous fat from 65 men and women. Most were clinically overweight or obese, and 39 had metabolic syndrome.

Subcutaneous fat from people with metabolic syndrome was rife with macrophages, a type of immune molecule that normally kills unwanted cells. But here, Jialal says, macrophages “appeared to be conspiring with fat cells to produce a host of proinflammatory cytokines,” whose levels correlated with an individual’s insulin resistance.

This proinflammatory environment was absent in people without metabolic syndrome — even among people who were very obese, the researchers report in the November Journal of Clinical Endocrinology & Metabolism, in an article posted online August 24. Although obesity predisposes people to develop metabolic syndrome, concludes Jialal, it takes more than excess fat to trigger it.

A related trial, published in the July 12 Journal of the American College of Cardiology, probed inflammation and metabolic impairments associated with subcutaneous fat in 109 obese men and women and 17 lean individuals. Some had diabetes but none had known heart disease.

“We found no inflammation in the fat of lean individuals,” who also had healthy blood vessel function, notes cardiologist Noyan Gokce of Boston University School of Medicine. In contrast, roughly 70 percent of the obese people had metabolic syndrome or at least some abnormal metabolic parameters in blood tests. These people also showed evidence of inflammation-promoting fat and impaired blood vessel function.

But the big surprise, Gokce says, was that the other roughly 30 percent of the obese people had very little inflammation inside their fat, little evidence of insulin resistance and vascular function that was the same as in lean people. “So it seems that the quantity of fat may not be nearly as important as its quality.”

The new data “open up the idea that maybe we should revisit subcutaneous fat as a major player in the metabolic consequences of obesity,” says Alyssa Hasty of Vanderbilt University School of Medicine in Nashville.

Found in: Body & Brain

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News in Brief: Molecules

Tracking the source of wines’ deep reds, fish oil goes to the brain and more in this week’s news. Web edition : Sunday, September 4th, 2011

Red, red wine
Scientists can now tell whether a glass of deep red vino acquires its color from grapes or rice. Deep reds can attract a higher price and winemakers will sometimes blend wines with Rossissimo, a wine that’s extra rich in red pigment. In some markets pigments extracted from black rice are also used as “correctors,” but in Italy this practice is frowned upon. Reporting in the Sept. 9 Analytica Chimica Acta, Italian researchers report that high-end spectroscopic techniques can discern rice red from Rossissimo red. —Rachel Ehrenberg

Omega-3s down, suicide risk up
The heart-healthy omega-3 fatty acids found in fish oils might also help keep the head healthy. A new study finds that U.S. military personnel who were at high risk for suicide also had low levels of DHA, or docosahexaenoic acid, the major omega-3 used by the brain. The study does not establish cause and effect, but it adds to a growing body of evidence linking low levels of omega-3s with mood problems including depression. Researchers from the National Institutes of Health and the Uniformed Services University of the Health Sciences in Bethesda, Md., report the work online August 23 in the Journal of Clinical Psychiatry. —Rachel Ehrenberg

Wines’ notes
Descriptions of wine typically involve notes of fruit or musk, not piano or woodwind. But people do make associations between a wine’s scent and particular musical instruments, new research shows. When 30 study participants had to choose a sound to match a wine’s bouquet, five odors were consistently linked with particular instruments, scientists from the University of Oxford in England report in an upcoming Chemical Senses. Vanilla and apricot connoted woodwind and piano; blackberry also inspired primarily piano; and musky wines were linked to brass. —Rachel Ehrenberg

Found in: Molecules

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FOR KIDS: Possible new saltwater stains on Mars

Dark streaks that grow in spring, fade in winter may point to saltwater on the Red PlanetWeb edition : Wednesday, August 31st, 2011 This image of a slope inside a Martian crater is actually a combination of several pictures taken by an instrument onboard the Mars Reconnaissance Orbiter. Scientists suspect the long, thin dark streaks are signs of saltwater that flows and then evaporates.HiRISE, MRO, LPL (U. Arizona), NASA

Here on Earth, it’s easy to find saltwater: Just head to the nearest sea. Oceans cover most of Earth’s surface, which means if you were to transport yourself to a random spot on our planet, you would probably end up all wet.

Visit the new Science News for Kids website to read the full story: Possible new saltwater stains on Mars

Found in: Science News For Kids

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A lighter Higgs, but chase continues

Target narrows with new estimated mass for elusive particleWeb edition : Thursday, September 1st, 2011 An actual collision between two protons produces showers of particles whose paths and energies are recorded by the Large Hadron Collider’s CMS detector. This spray of electrons (thick red lines) and muons (thin red lines) looks similar to what would be expected from the Higgs, but could also be a background fluctuation.L. Taylor and T. McCauley/COPYRIGHT CERN 2011

In the hunt for the Higgs boson, the world’s most powerful particle collider has tightened the net. New data collected this year by CERN’s Large Hadron Collider near Geneva narrow the range of allowable masses for the hypothetical particle, whose existence would confirm the mechanism thought to give mass to other particles.

To fit with the standard model, the cornerstone of modern particle physics, the Higgs must now be lighter than 145 billion electron volts, or GeV. Team members from LHC’s ATLAS and CMS experiments presented their results August 22 in Mumbai, India at the International Symposium on Lepton Photon Interactions at High Energies.

This new limit goes beyond previous results from the Tevatron at the Fermi National Accelerator Laboratory in Batavia, Ill. — which directly excluded 156 to 177 GeV by looking for debris left behind when the Higgs breaks down, and indirectly ruled out masses above 185 GeV using theoretical calculations and measurements of other particles.

“We’ve now confirmed with direct searches that the mass of standard model Higgs, if it exists, is light,” says CERN’s Fabiola Gianotti, a spokeswoman for ATLAS.

Even as it runs out of room to hide, though, the Higgs is still playing hard to get. Faint hints of the Higgs that turned up at the LHC in July — particles with energies that could indicate a lighter Higgs — have only grown fainter in the new LHC data. No statistically significant signs of the Higgs have appeared in the rest of the remaining mass range.

A lighter Higgs is harder to find at the LHC. At lower energies, its signature tends to fade into the background. But CERN physicists still expect to discover or rule out the existence of such a particle in the next two years.

Found in: Atom & Cosmos and Matter & Energy

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Saffron takes on cancer

Harvested from the Crocus sativus flower (shown), saffron stifles liver cancer’s growth in rats and even inhibits the proliferation of human liver cancer cells, a new study finds. KENPEI/Wikimedia Commons

Best known as a food seasoning and dye, saffron can also stifle liver cancer in rats, tests show. In a report in the September Hepatology, researchers find that the spice suppresses a slew of known cancer-related compounds and boosts several beneficial ones.

Saffron is an expensive spice made from the Crocus sativus flower. Past studies have hinted it has benefits against depression, inflammation, memory loss and as an antioxidant. Studies in animals and in human cells have even suggested that saffron can inhibit certain cancers. “But the exact mechanism of the anticancer effect of saffron is unclear,” says Amr Amin, a molecular biologist at United Arab Emirates University in Al-Ain.

Although the spice has been used as a folk remedy for centuries, only in recent decades has its value been tested in the laboratory. In the new study, Amin and his colleagues fed saffron to 24 rats daily for 24 weeks. Two weeks into the regimen the researchers injected the animals with diethylnitrosamine and 2-acetylaminofluorene, a chemical combination known to cause liver cancer.

Eight other rats getting a similar injection combo received distilled water instead of saffron. Six of them developed cancerous growths called nodules on the liver during the course of the study, whereas only four of the 24 rats getting saffron developed nodules. Of eight rats that got the highest dose of saffron, none developed any nodules.

Amin says his team chose to study liver cancer because cancers that spread from other organs, such as the colon or breast, often end up there.

Saffron kept in check a cell-proliferation protein called Ki-67 and reduced other compounds linked to liver damage and oxidative stress. Oxidative stress results from an imbalance between unstable, reactive molecules called free radicals and the antioxidants that sop them up. This tilt can lead to aberrant cell growth, a precursor to cancer, Amin says. Antioxidants, including one called superoxide dismutase, were restored in the rats getting saffron.

A separate series of tests on human liver cancer cells showed that saffron inhibits the action of key proteins — NF-kappa B, interleukin-8 and tumor necrosis factor receptor 1 — that contribute to cell proliferation and inflammation. Other evidence shows that saffron switches on programmed cell death in cancerous cells, a failsafe mechanism that is often shut down in cancer.

“This is very extensive work, and the quality is very good,” says Tapas Saha, a molecular biologist at the Georgetown University Lombardi Comprehensive Cancer Center. But Saha, who wasn’t involved in this study, says that scaling up these findings to apply them as a treatment in people might be a challenge. Saffron must be hand-picked, he notes, and so the price remains high. “Saffron is such a costly material,” he says, “that it’s very difficult to understand how it can be a drug.”

Synthetic versions of the important saffron components might be less expensive. Amin says further research may delineate those constituents.  Meanwhile, the team plans to test the spice in liver cancer patients.

Found in: Body & Brain

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Middle school scientists recognized

Finalists in inaugural Broadcom MASTERS competition announcedWeb edition : Wednesday, August 31st, 2011

Thirty talented sixth-, seventh- and eighth-graders have raised the bar for the question, “Are you smarter than a middle schooler?” These science-minded youngsters have advanced to the final round of a new national competition, the first ever Broadcom Math, Applied Sciences, Technology and Engineering for Rising Stars program, or MASTERS event.

Finalists were chosen for their original research projects, which covered a range of scientific topics — from the cognitive benefits of yoga to the physics that gives light to LEDs. Following last year’s Deepwater Horizon oil spill, one student in Texas tested how oil and chemicals that disperse oil impact algae. Another used a computer simulation to investigate dark matter’s influence on rotating galaxies.

In October the selected students will travel to Washington, D.C., where they will present their projects to the public, visit Capitol Hill to meet members of Congress and vie for prizes in team challenges.

“Middle school is the time when a boy or girl first develops independent desires and interests,” says Paula Golden, executive director of Broadcom Foundation and director of community affairs for Broadcom Corp. “Engaging in a science or engineering project at this age may well ignite a passion that will inspire a middle schooler to stay with math and science.”

The 2011 Broadcom MASTERS is sponsored by the Broadcom Foundation and Society for Science & the Public, which publishes Science News. Past finalists of another competition administered by SSP — the annual Intel Science Talent Search for high school seniors — have gone on to win Nobel Prizes, among other accolades.

“In addition to launching science careers, SSP’s competitions motivate students to view the world through a scientific lens, essential for the navigation of issues that affect everyone in today’s complex global society,” says Elizabeth Marincola, president of SSP and publisher of Science News. 

In its first year, the Broadcom MASTERS program received 1,476 entries from students who were nominated by local science fairs in 45 states, Washington, D.C., and Puerto Rico. A panel of scientists and engineers whittled the applicants down to 300 semifinalists.

The selection of the 30 finalists on August 31 brought good news for the participating schools: Each winner’s school will receive $1,000 from the Broadcom Foundation. A single overall winner, to be announced at an October 4 gala, will receive the top prize, a $25,000 educational award presented by the Samueli Foundation, a private foundation based in Corona Del Mar, Calif.

2011 Broadcom MASTERS Finalists

ARIZONA
Meagen Bethel, Tucson, Doolen Middle School

CALIFORNIA
Namrata Balasingam, San Jose, Challenger School, Strawberry Park
Braden Benedict, Rancho Palos Verdes, Saint John Fisher Parish School
Daniel Feeny, Woodside, Woodside Elementary School
Crystal Poole, San Diego, Thurgood Marshall Middle School

FLORIDA
Maria Grimmett, Jupiter, The Weiss School
Nikhil Patel, Geneva, Stanford Middle School

HAWAII
Robert Heckman, Kailua, Kailua Intermediate School
Jordan Kamimura, Hilo, Hilo Intermediate School

MASSACHUSETTS
Nathan Han, Boston, Jackson Mann K-8 School
Emily Sarkisian, Mansfield, St. Mary’s Catholic School

MINNESOTA
Roshini Asirvatham, Rochester, Friedell Middle School
Carolyn Johns, Eden Prairie, Central Middle School

NORTH CAROLINA
Justin Barber, Raleigh, St. Timothy’s School
Chad Campbell, Hampstead, Topsail Middle School

NEW MEXICO
Coleman Kendrick, Los Alamos, Los Alamos Middle School

OHIO
Kyle Davis, Sunbury, Big Walnut Middle School
Jennifer Markley, Westerville, Walnut Springs Middle School
Samantha Rowland, Tipp City, Tippecanoe Middle School

OREGON
Valerie Ding, Portland, Summa North at Meadow Park Middle School
Anirudh Jain, Portland, Summa North at Meadow Park Middle School
Mahita Tovinkere, Portland, Stoller Middle School

PENNSYLVANIA
Benjamin Hylak, West Grove, Sacred Heart School

PUERTO RICO
Adriana Monzon, Guaynabo, Academia del Perpetuo Socorro

SOUTH CAROLINA
William White, Hilton Head, Hilton Head Preparatory School

TEXAS
Ria Chhabra, Plano, Renner Middle School
Alicia D’Souza, Plano, C.M. Rice Middle School
Lauren Hall, Corpus Christi, School of Science and Technology
I-Chun Lin, Plano, Schimelpfenig Middle School

WASHINGTON
Katherine Landoni, Sequim, Sequim Middle School

Found in: Science & Society and Science News For Kids

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Oldest hand axes found

African discoveries offer glimpse of early tool-making complexityWeb edition : Thursday, September 1st, 2011 OLD AND EDGYA stone hand ax (shown from different angles), dating to 1.76 million years ago, comes from the earliest known culture to have made such implements.P.-J. Texier, copyright MPK/WTAP

A patch of soil in East Africa has yielded the oldest known stone hand axes and picks, examples of what researchers call the Acheulian industry.

Acheulian implements unearthed at Kenya’s Kokiselei site date to 1.76 million years ago, slightly older than previous finds (SN: 1/31/09, p. 11), say geologist Christopher Lepre of Rutgers University and his colleagues. Carefully shaped, double-edged hand axes and picks lay among much simpler tools — sharp flakes pounded off stones — at Kokiselei, the scientists report in the Sept. 1 Nature.

These finds underscore suspicions that stone flakes used as chopping devices, early tools known as the Oldowan industry, did not get supplanted by hand-ax making, Lepre says. Instead, the more complex Acheulian devices emerged while Oldowan implements — which first appeared about 2.6 million years ago in the same region — were still popular, although it’s unclear how long the two types of tools were used simultaneously at Kokiselei. Hand axes and other double-edged tools typify the Acheulian industry.

Homo erectus, a possible direct ancestor of modern humans, made Acheulian tools and perhaps Oldowan ones as well at Kokiselei, Lepre’s team suggests. Or, another hominid species might have crafted Oldowan artifacts there.

“If Acheulian tools gave hominids an edge in Africa, then perhaps groups lacking that technology were forced to find resources elsewhere, like Eurasia,” Lepre says.

In line with that proposal, other researchers have unearthed H. erectus fossils at Dmanisi, a West Asian site as old as Kokiselei, along with simple chopping stones but no hand axes. It remains unsettled whether H. erectus, which first appeared around 2 million years ago, evolved in Africa or Asia.

Lepre’s team estimated the age of the Kokiselei tools by taking measurements in and around artifact-bearing soil of ancient reversals in Earth’s magnetic field, combined with previously dated volcanic ash layers sandwiching the finds.

Archaeologists familiar with the new paper say that it moves the origin of Acheulian tools back a bit closer to the evolutionary debut of H. erectus, an interesting but not unexpected development.

Excavations at Israel’s 'Ubeidiya Formation have recovered 1.5 million-year-old hand axes and picks, presumably made by H. erectus, that resemble those from Kokiselei, remarks Naama Goren-Inbar of the Hebrew University of Jerusalem. Acheulian sites in Tanzania and India also date to as early as 1.5 million years ago.

Some sets of Oldowan and Acheulian artifacts look much alike, implying that the same hominid species could have produced both tool types, Goren-Inbar says.

Harvard University’s Ofer Bar-Yosef agrees. “Homo erectus could have made all of the stone tools at Kokiselei,” he asserts.

Fossils are needed to confirm that H. erectus made these implements, comments John Shea of Stony Brook University in New York. Simple flakes struck off stones augmented more complex tools throughout the Stone Age, although archaeologists often ignore Oldowan artifacts at modern human sites, Shea argues.

Found in: Anthropology, Archaeology and Humans

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News in Brief: Earth & Environment

The supercontinent of the future, pollutants from laundry detergent and more in this week’s news Web edition : Saturday, September 3rd, 2011

Clouds intensify soot’s Arctic heating
Reining in soot production could dramatically slow Arctic warming, Mark Jacobson of Stanford University reported August 31 in Denver at the American Chemical Society’s national meeting. Soot’s presence in water droplets heats clouds much more than it does the black carbon particles between cloud droplets, new computer analyses show — which Jacobson says “helps to explain the burning off of clouds in polluted regions.” Once clouds disappear, more sunlight reaches the surface to melt sea ice and warm Arctic waters. But curbing all soot that now wafts into the Arctic could within 15 years eliminate 15 to 20 percent of the total warming contribution to the region, which could reduce the net temperature rise by 50 percent, his computer projections indicate. —Janet Raloff

Bedrock can help the climate
Researchers from the University of California, Davis offer data that could overturn the conventional wisdom about where new nitrogen in land-based ecosystems comes from. It’s supposed to come from the atmosphere. Butforests and local soils underlain with nitrogen-rich sedimentary rock contain 50 percent more nitrogen, a fertilizer, than do those atop nitrogen-poor rock, the scientists report in the Sept. 1 Nature. These researchers fingerprinted the bonus nitrogen to the weathering of bedrock below. Forests and soils over nitrogen-releasing rock also contained substantially more carbon than in nitrogen-poor areas, the scientists found, demonstrating that bedrock can dramatically boost the carbon-sequestering climate benefits of some forests. —Janet Raloff

Clean-smelling clothes dirty the air
Fragrance chemicals in detergents and dryer sheets can release toxic chemicals — none listed on product labels — especially into the air vented from a dryer. Anne Steinemann of the University of Washington in Seattle and her colleagues did laundry using no products, scented detergents, and detergents plus dryer sheets. The researchers report online August 19 in Air Quality, Atmosphere & Health finding substantial quantities of airborne organics including seven chemicals considered hazardous, two of which are potential carcinogens: acetaldehyde and benzene. Acetaldehyde measurements, if extrapolated to all users of the top five detergent brands throughout the county, could equal 6 percent of that toxic chemical’s releases from area cars if all the detergents produce the same levels the test detergent did, the researchers calculate. —Janet Raloff

Triggering earthquakes
Injecting carbon dioxide deep underground to keep it from entering the atmosphere can trigger earthquakes on local faults, a new study suggests. Scientists from the Lawrence Berkeley National Laboratory in California and the Côte d’Azur Observatory in France simulated what would happen if carbon dioxide entered an underground reservoir with a common kind of fault nearby. Depending on how and when the injection was done, an earthquake of up to magnitude 4.5 could occur, the team reports in a paper to appear in Geophysical Research Letters. Oil exploration, geothermal and other companies want to understand the conditions under which injections cause earthquakes. —Alexandra Witze

Supercontinent of the future
Continental drift, combined with heat from deep within Earth, could push North America, Eurasia, Australia and Africa together to form a new supercontinent in the Northern Hemisphere within the next 250 million years. Although scientists know about past supercontinents such as Pangaea, speculating about future landmasses has been something of a guessing game. Now, scientists in Japan have modeled heat welling up from Earth’s mantle and suggested exactly how that could drive today’s continents together. Antarctica and South America never join the future supercontinent, the team reports online August 17 in Terra Nova. —Alexandra Witze

Found in: Earth and Environment

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News in Brief: Life

Bird marriages hurt by city hubbub, tadpoles poison their own kind and more in this week's newsWeb edition : Thursday, September 1st, 2011 TURTLE TRACKINGHawksbill turtles like the one shown here are surprising researchers by heading into forested estuaries instead of reef waters.Aquaimages/Wikimedia Commons

Hawksbill turtles in funny places

Tracking imperiled hawksbill turtles in the eastern Pacific with satellite tags has left turtle biologists startled by locations in completely unexpected places. In the Caribbean and Indo-Pacific regions, hawksbills cruise reefs and waters near shore that face open ocean. Yet tag data revealed most of the 12 female turtles followed along the Pacific coast of El Salvador, Honduras, Nicaragua and Ecuador were hanging out in shallower waters such as inshore estuaries and seemed to especially like mangrove forests. Turtle conservation strategies need rethinking, an international research team reports online August 31 in Biology Letters. —Susan Milius

Urban noise ruined my marriage

Traffic rumbling and other urban noise that prompt males of a European bird species called the great tit to cut back on sexy, low-pitched morning serenades may lead to more philandering by their female partners. In the latest twist in studies on how human noise affects city-dwelling animals, researchers at Leiden University and Gronigen University in the Netherlands experimented with sound and song at tit nest boxes. Female birds preferred deeper voices, and males that didn’t croon low as much were more likely to be cuckolded than those that did, Wouter Halfwerk and his colleagues report Aug. 30 in  Proceedings of the National Academy of Sciences. —Susan Milius

Tadpole-on-tadpole WMD

A new avenue for research on chemicals to control the massive, poisonous cane toads that are spreading across Australia has come from the tadpoles of the species. Chemical cues that the tadpoles release into the water can suppress the development of cane toad embryos still in eggs such that they hatch into punier tadpoles that don’t survive or grow well, report researchers from the University of Sydney online August 31 in Biology Letters. The toads, introduced in a regrettable attempt to control another pest, are disrupting the native ecosystems. —Susan Milius

Found in: Life

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News in Brief: Humans

Humans and Neandertals may not have interbred, after all, the backlash of selfishness and more in this week's news

No Neandertal hanky-panky
New mitochondrial DNA analyses indicate that Neandertals didn’t occasionally interbreed with Stone Age humans, as proposed in a recent study of Neandertal nuclear DNA, say evolutionary biologist Guido Barbujani of the University of Ferrara in Italy and his colleagues. Barbujani’s team analyzed maternally inherited mitochondrial DNA from European Neandertals, Stone Age Europeans and living Europeans. If nuclear DNA lines leading to Neandertals and Europeans are older than corresponding mitochondrial DNA lines, then a long period of shared ancestry could explain why Neandertals and today’s Europeans share some nuclear DNA, the researchers propose online August 24 in the American Journal of Physical Anthropology. —Bruce Bower

Psychling dynamics
Although cyclist Alberto Contador won the 2009 Tour de France, he was criticized for defecting from his teammates and sprinting ahead when tactics demanded patience. A new analysis suggests that criticism was on mark. When strong riders break away from their companions, it helps the defector but hurts the team, researchers report in an upcoming issue of Complexity. University of Colorado at Boulder scientists and a sports psychologist from a professional team developed a bike racing model incorporating variables such as cooperation, defection, speed, distance and effort. The model nicely captures real racing dynamics: below-average riders fare better as defectors, above-average riders as cooperators, and when a strong rider does defect, it really screws his team. —Rachel Ehrenberg

Depression-fighting beliefs
Strong religious and spiritual beliefs may defend against recurrences of depression, especially if this mood disorder runs in a person’s family. Among individuals tracked for 10 years, those who considered religion and spirituality important in their lives displayed a markedly lower rate of major depression than those who didn’t, say psychologist Lisa Miller of Columbia University in New York City and her colleagues. Religion’s protective effect was greatest for those who had depressed mothers, the researchers  report online August 24in the American Journal of Psychiatry. Most of those high-risk individuals had been treated for bouts of depression before the study began. —Bruce Bower

Neandertals’ varied menu
Often portrayed as meat-obsessed big-game hunters, Neandertals may have had broader tastes. Neandertals that lived in southern France between 250,000 and 125,000 years ago ate fish, birds and starchy plants as well as wild cattle,  deer and wild horses, two anthropologists report online August 24 in PLoS ONE. Microscopic residue and edge-wear patterns on Neandertal stone tools previously unearthed at a French site called Payre reveal a varied diet that may have been missed in previous studies of butchered animal bones, say Bruce Hardy of Kenyon College in Gambier, Ohio, and Marie-Hélène Moncel of the National Museum of Natural History in Paris. —Bruce Bower

Found in: Humans

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Acid oceans helped fuel mass extinction

The question of what killed most life on Earth 250 million years ago is a veritable Murder on the Orient Express, with multiple characters all dealing part of the deathblow. Now, scientists have learned how one of the assassins — acid — could have performed its part of the deed.

High levels of atmospheric carbon dioxide would have turned the oceans more than acidic enough to kill off marine critters, a computer simulation indicates.

“This would have been another stressor in the system that might have pushed things toward extinction,” says Alvaro Montenegro, a climate modeler at St. Francis Xavier University in Antigonish, Nova Scotia. He and his colleagues describe the finding in a paper published online August 2 in Paleoceanography.

At the end of the Permian period of geologic time, more than 90 percent of marine species and three-quarters of terrestrial species vanished. Leading suspects in the die-off include oxygen-starved oceans, a belch of hydrogen sulfide from the deep, a shutdown of great marine nutrient cycles, and massive volcanic eruptions.

Using a climate model developed at the University of Victoria, Montenegro and  colleagues set up nine hypothetical worlds — mixing and matching possible continental arrangements, seafloor topographies and levels of atmospheric carbon dioxide. Then the researchers fired up the model and watched how carbon flowed through the ocean and atmosphere.

At atmospheric carbon dioxide levels of 3,000 parts per million — roughly 10 times modern preindustrial levels — much of the gas dissolved in seawater, forming carbonic acid and releasing hydrogen ions. Acidity is measured on the pH scale; the lower the number, the more acidic the waters. Today’s oceans have a pH of around 8.1; those in the modeled end-Permian world dropped to around 7.3 near the equator and 7.1 near the poles. Such acidity would have made it hard for many marine organisms to use calcium carbonate to build protective shells, Montenegro says.

Today’s oceans also are growing more acidic because of carbon dioxide belched into the atmosphere by fossil fuel burning and other sources. Back then, most of the gas probably came from huge volcanic eruptions in Siberia.

How quickly carbon dioxide built up in the atmosphere would have affected how acidic the ocean got, says Jonathan Payne, a paleobiologist at Stanford University. If gas concentrations increased quickly, he says, “then this model may be a reasonable representation of how climate was changing at the time.” If gas built up slowly, the oceans may have been able to buffer the change in other ways.

But the model doesn’t include factors such as carbon weathering off land surfaces and into the oceans — an important player in the carbon cycle, says Lee Kump, a modeler at Pennsylvania State University in University Park. Including such effects, he says, could better show how life’s worst extinction came to pass.

Found in: Earth, Life and Paleobiology

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News in Brief: Genes & Cells

Bacterium’s DNA mostly unused, the death of Black Death and more in this week’s newsWeb edition : Friday, September 2nd, 2011

Life’s essentials
Most of the DNA in the bacterium Caulobacter crescentus really isn’t necessary. Researchers used genetic tricks to map out the pages of the bacterium’s genetic instruction book that are essential to life in the lab. Of Caulobacter’s 3,876 genes, only 480 are essential, Stanford microbiologist Lucy Shapiro  and her colleagues report online August 30 in Molecular Systems Biology. Also necessary are 402 pieces of DNA that govern activity of genes and 130 pieces of DNA that don’t encode proteins. Of the 130 “non-coding” bits, “90 don’t fit any of the categories we know about, and we don’t have a clue what they do,” Shapiro says. —Tina Hesman Saey

Black Death bacterium is extinct
Fear not. A version of the plague bacterium that wiped out at least 30 percent of Europe’s population between 1347 and 1351 is a goner. Scientists have debated whether the plague bacterium Yersinia pestis really caused the Black Death because that plague had different symptoms than modern outbreaks of bubonic or pneumonic plague. Now scientists from the University of Tübingen in Germany and McMaster University in Canada and colleagues have found traces of Y. pestis in skeletons of Black Death victims. The team reports online August 29 in the Proceedings of the National Academy of Sciences that the Black Death bacterium was genetically different from modern plague strains and probably no longer exists. —Tina Hesman Saey

Yellow eyes get less sleep
Elderly people’s sleeping problems may be due to a natural yellowing of the eyes with age, a new study suggests. Researchers at the University of Copenhagen examined 970 Danish people between 30 and 60 years old. The team found that as people age, the lenses of their eyes yellow slightly, blocking out blue light wavelengths that help synchronize the body’s daily rhythms. The less blue light that got through to the retina, the more likely people were to have sleep disturbances, the researchers report in the Sept. 1 Sleep. Yellowing is sped up in smokers and people with diabetes and heart disease. —Tina Hesman Saey

Ancient antibiotic resistance
People have been fighting bacteria with antibiotics for more than 70 years, but a new study finds that the microbes have had at least a 30,000-year head start on building resistance. The finding, published online August 31 in Nature, contradicts the idea that resistance to antibiotics is a modern phenomenon brought about by misusing the drugs. Researchers at McMaster University in Hamilton, Canada, and colleagues isolated ancient DNA about 30,000 years old from the permafrost near Dawson City, Canada, and found genes for proteins that work together to inactivate the antibiotic vancomycin. Resistance to that antibiotic was previously thought to have first arisen in the late 1980s. —Tina Hesman Saey

Found in: Genes & Cells

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