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Teenagers programmed to take risksRisk-taking peaks in adolescence, according to scientists in the UK. In a new study, children, adolescents and adults aged 9-35 years chose between risky and safe options in a computer gambling game. Scientists found that the teenagers took the most risks compared with the other groups, with the most risky behaviour seen in 14-year olds.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 12:00 pm Bathing and showering: Under-appreciated sources of water pollution from medicinesThat bracing morning shower and soothing bedtime soak in the tub are potentially important but until now unrecognized sources of the hormones, antibiotics, and other pharmaceuticals that pollute the environment, scientists have reported.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 12:00 pm 'Doublesex' gene key to determining fruit fly genderThe brains of males and females, and how they use them, may be far more different than previously thought, at least in the fruit fly Drosophila melanogaster, according to new research.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 12:00 pm New bird fossil hints at more undiscovered Chinese treasuresThe study of Mesozoic birds and the dinosaur-bird transition is one of the most exciting and vigorous fields in vertebrate paleontology today. A newly described bird from the Jehol Biota of northeast China suggests that scientists have only tapped a small proportion of the birds and dinosaurs that were living at that time, and that the rocks still have many secrets to reveal.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 12:00 pm Anesthesia increases risk of developing Alzheimer's disease in patients with genetic predisposition, study suggestsThe use of repetitive anesthesia with isoflurane (one of the most common anesthetics by inhalation) increases the risk of developing changes similar to those observed in AD brains in mice with mutations of the amyloid precursor protein.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 12:00 pm Pesticide chlorpyrifos linked to childhood developmental delaysExposure to the pesticide chlorpyrifos -- which is banned for use in US households but is still widely used throughout the agricultural industry -- is associated with early childhood developmental delays.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 12:00 pm Plant breeding breakthrough: Offspring with genes from only one parentA reliable method for producing plants that carry genetic material from only one of their parents has been discovered by plant biologists. The technique could dramatically speed up the breeding of crop plants for desirable traits.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 9:00 am Versatility of optogenetics brain-research technique vastly expandedRecently, brain researchers have gained a powerful new way to troubleshoot neural circuits associated with depression, Parkinson's disease and other conditions in small animals such as rats. They use an optogenetics technology that precisely turns select brain cells on or off with flashes of light. Although useful, the optogenetics tool set has been limited. Researchers have now developed major advances that will enable a much wider range of experiments in larger animals.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 9:00 am New findings about how cells achieve eternal lifeResearchers can now show that cells that grow forever get this capacity through gradual changes in the expression of genes that govern the repair of DNA damage and regulate growth and cell death. The research also shows that activation of the enzyme complex telomerase, which is necessary for unlimited growth, occurs late in this process.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 9:00 am Guinea pigs not 'dumbed down' by domesticationDespite reductions in brain size, domestication has not reduced the ability of guinea pigs to navigate a water maze. Researchers tested domesticated and wild animals ("cavies") and found that they both performed well at the test, with the domestic animals actually being slightly superior.Source: ScienceDaily: Latest Science News | 25 Mar 2010 | 9:00 am Food push urged to avoid hungerBig investments in agriculture are needed if the world is to feed its swelling population, a major report warns.Source: BBC News | Science & Environment | UK Edition | 25 Mar 2010 | 4:07 am DNA identifies new ancient humanScientists identify a previously unknown type of ancient human by analysing DNA from a finger bone.Source: BBC News | Science & Environment | UK Edition | 25 Mar 2010 | 3:53 am Japan big winner at UN conservation meeting (AP)
Source: Yahoo! News: Science News | 25 Mar 2010 | 3:30 am The nation's weather (AP)
Source: Yahoo! News: Science News | 25 Mar 2010 | 2:57 am Mars Rover Opportunity is Thinking for ItselfAfter NASA sent a sophisticated software upgrade to Mars Exploration Rover Opportunity, the wheeled robot can now "choose" which rocks to investigate. Mars exploration just got smarter.Source: Discovery News - Top Stories | 25 Mar 2010 | 12:21 am Bullies Pick on Unpopular Kids, Study FindsBullies as young as 10 strategically prey on the unpopular students, hoping to boost their status while not losing the affection of the in-group.Source: Livescience.com | 24 Mar 2010 | 11:06 pm Step up climate efforts, MPs sayFar more needs to be done by the government to help the UK adapt to climate change, MPs have said.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 10:58 pm Bullies Pick on Unpopular Kids, Study Finds (LiveScience.com)LiveScience.com - Bullies choose their victims wisely, targeting kids who are unpopular and less likely to be defended by their peers, a new study finds.Source: Yahoo! News: Science News | 24 Mar 2010 | 10:15 pm What's Cookin'? It Could Be Air Pollution (HealthDay)HealthDay - WEDNESDAY, March 24 (HealthDay News) -- The enticing aromas that restaurants emit are actually a type of air pollution that could pose a risk to your health and the environment, U.S. researchers report.Source: Yahoo! News: Science News | 24 Mar 2010 | 9:49 pm Gene Holds Key to Embryonic Stem Cell Rejuvenation (HealthDay)HealthDay - WEDNESDAY, March 24 (HealthDay News) -- Scientists have identified a gene in mice that is a key player in what could essentially be called embryonic stem cells' "immortality."Source: Yahoo! News: Science News | 24 Mar 2010 | 9:49 pm Researchers Identify 2 Genes Linked to Fatty Liver Disease (HealthDay)HealthDay - WEDNESDAY, March 24 (HealthDay News) -- Researchers have identified two gene variants that increase the risk of both the most common chronic liver disease in the United States as well as type 2 diabetes.Source: Yahoo! News: Science News | 24 Mar 2010 | 9:49 pm Swine flu virus not so new, study findsWASHINGTON (Reuters) - The H1N1 swine flu virus may have been new to humanity in many ways but in one key feature its closest relative was the 1918 pandemic virus, researchers reported on Wednesday.Source: Reuters: Science News | 24 Mar 2010 | 8:46 pm Canadians Use Yellow Bots to Explore the ArcticCanada has a high tech toy to help them win the New Arctic Land Grab: a big, yellow submarine.Source: Discovery News - Top Stories | 24 Mar 2010 | 6:21 pm 'Oldest' osprey returns to nestThe UK's oldest known breeding female osprey returns to Scotland from West Africa for the 20th consecutive year.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 6:11 pm Bright Fireball Caught on Camera Over Alabama (SPACE.com)SPACE.com - A bright fireball that lit up the sky above parts of Alabama last week was caught by NASA cameras as it streaked over the southeastern United States.Source: Yahoo! News: Science News | 24 Mar 2010 | 5:15 pm Last Chance to Get a Good Look at Mars Until 2012 (SPACE.com)
Source: Yahoo! News: Science News | 24 Mar 2010 | 5:15 pm Maths behind Internet encryption wins top awardAbel prize awarded to number theorist John Tate.<img src="http://feeds.feedburner.com/~r/news/rss/today/~4/Em1Z5a-seEw" height="1" width="1"/>Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 5:00 pm How 1918 flu antibodies fend off swine fluStructural similarities reveal why some elderly people were spared in the recent pandemic.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:30 pm Methane-eating microbes make their own oxygenBacteria may have survived on Earth without plants, thanks to unique metabolism.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:01 pm Fossil finger points to new human speciesDNA analysis reveals lost relative from 40,000 years ago.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:01 pm Soils emitting more carbon dioxideTrend could exacerbate global warming.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:01 pm Physics: The Large Human ColliderSocial scientists have embedded themselves at CERN to study the world's biggest research collaboration. Zeeya Merali reports on a 10,000-person physics project.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:00 pm Ageing: Much ado about ageingQuestions about a laboratory assay are making Sirtris, a high-profile biotechnology company, the talking point of the ageing field. Heidi Ledford investigates.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:00 pm CorrectionSource: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 4:00 pm E. Coli: Not Just for Carnivores AnymoreWhen the topic of eating meat comes up, on occasion my vegan and vegetarian friends will recite a list of reasons they abstain from consuming the flesh of animals. (Not that they need to justify anything to me; I always ...Source: Discovery News - Top Stories | 24 Mar 2010 | 3:30 pm Finding the Cracks in U.S. Water SafetyMarc Edwards has devoted his career to finding potential hazards in the U.S. water supply.Source: Livescience.com | 24 Mar 2010 | 3:19 pm Scientists find how relaxed minds remember betterLONDON (Reuters) - Stronger and more lasting memories are likely to be formed when a person is relaxed and the memory-related neurons in the brain fire in sync with certain brain waves, scientists said on Wednesday.Source: Reuters: Science News | 24 Mar 2010 | 3:12 pm Harrabin's NotesWhat does latest UK Budget mean for green energy?Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 2:35 pm DNA Reveals New Hominid Ancestor
A new member of the human evolutionary family has been proposed for the first time based on an ancient genetic sequence, not fossil bones. Even more surprising, this novel and still mysterious hominid, if confirmed, would have lived near Stone Age Neandertals and Homo sapiens.
The researchers base their claim on DNA from a finger bone belonging to a hominid that lived in the Altai Mountains of central Asia between about 48,000 and 30,000 years ago. Anthropologists have generally assumed that hominids left Africa in a few discrete waves, starting with Homo erectus about 1.9 million years ago. Neandertal ancestors left between 500,000 and 300,000 years ago, followed by humans around 50,000 years ago. But the new genetic sequence supports a scenario in which many African hominid lineages trekked to Asia and Europe in the wake of H. erectus, Pääbo suggests.
While retrieving DNA from presumed Neandertal fossils in November 2009, Krause noticed an unusual mitochondrial sequence. Mitochondrial DNA is located outside the cell nucleus and inherited from the mother. Krause conducted tests to confirm that the newly recovered mitochondrial DNA came from an ancient hominid rather than from bacteria or researchers who had handled the fossil. Using advanced techniques for fishing DNA fragments out of fossils, the team then assembled a complete mitochondrial genome for the Denisova individual. The same approach has yielded ancient DNA sequences for Neandertals (SN: 3/14/09, p. 5) and a Greenland man who lived 4,000 years ago (SN: 3/13/10, p. 5). The researchers compared Denisova mitochondrial DNA to complete mitochondrial sequences from 54 people who are living today as well as a human who lived in Siberia about 30,000 years ago, six Neandertals from more than 40,000 years ago, a modern pygmy chimpanzee and a modern common chimp. Mitochondrial DNA from the Denisova fossil differs from that of humans at almost twice as many chemical positions as Neandertal mitochondrial DNA does, Krause says. “That number of differences is good evidence for a new hominid because simple variation can’t account for it,” remarks geneticist Morten Rasmussen of the University of Copenhagen. Assuming that mitochondrial DNA ancestors of humans and chimps diverged 6 million years ago, the researchers calculate that a mitochondrial ancestor common to the Denisova hominid, Neandertals and modern humans lived between 779,300 and 1,313,500 years ago. A common mitochondrial DNA ancestor of modern humans and Neandertals lived more recently, an estimated 321,200 to 618,000 years ago. Krause and Pääbo are now directing an effort to extract nuclear DNA from the Denisova fossil. Comparisons of Denisova, Neandertal and modern human nuclear DNA are needed to confirm that the finger bone comes from a new hominid species and to check for signs of interbreeding with Neandertals or humans. For now, the researchers refer to the Denisova hominid as “X woman,” although its sex remains undetermined until nuclear DNA can be examined. X woman’s finger bone came from a soil layer that has yielded bracelets and other artifacts usually attributed to humans, Krause notes. “What we can say for now is that there were at least three different forms of hominids living in the Altai Mountains around 40,000 years ago,” Pääbo says. At that same time, Homo floresiensis, better known as hobbits, occupied the Indonesian island of Flores (SN: 5/10/08, p. 7). Hobbit DNA has yet to be recovered. In a comment published with the new report, geneticist Terence Brown of the University of Manchester says that further ancient DNA studies will “possibly increase the crowd of ancestors that early modern humans met when they travelled into Eurasia.” Anthropologist Ian Tattersall of the American Museum of Natural History in New York City agrees. Hominid evolution over the past 6 million to 7 million years includes at least two dozen species, in Tattersall’s view. It was “practically routine” for two or more species to live in the same general area at the same time, he says. Tattersall regards the new mitochondrial DNA sequence as so distinctive that, unless disproved by further evidence, it must represent a new type of hominid. In contrast, anthropologist Erik Trinkaus of Washington University in St. Louis views the new genetic data skeptically. “I don’t know what to make of this, at least not until there is more substantial fossil material than a partial finger bone,” he says. “It may be going too far to propose a new hominid.” Trinkaus, who sees fewer species in the hominid family than Tattersall, cautions that biologists have difficulty identifying different species even among living primates. For example, groups of baboons that usually live apart as apparently separate species sometimes aggregate and interbreed, muddying their classification. Pääbo acknowledges the complexity of finding new hominids in mitochondrial DNA, which in animals such as mice can pass from one species to another via interbreeding. “But there are massive genetic differences between X woman and both Neandertals and modern humans,” he says. Images: Johannes Krause
Source: Wired: Wired Science | 24 Mar 2010 | 2:13 pm News briefing: 25 March 2010The week in science.Source: NatureNews - All articles published today - nature.com science feeds | 24 Mar 2010 | 2:00 pm New ancestor? Scientists ponder DNA from Siberia (AP)
Source: Yahoo! News: Science News | 24 Mar 2010 | 1:35 pm New human species foundHuman relative, identified from fragments of a finger bone, lived until as recently as 30,000 years ago, say scientists The remains of a little finger discovered in a cave in the mountains of southern Siberia belong to a previously unknown human ancestor, scientists said today. The finding suggests an undocumented human species lived alongside Neanderthals and early modern humans in parts of Asia as recently as 30,000 years ago. If confirmed, it would be the first time a new human ancestor has been identified since the discovery of Homo floresiensis, the diminutive "hobbits" that lived on the Indonesian island of Flores until 13,000 years ago. Fragments of the finger bone were recovered from Denisova cave in the Altai mountain range that straddles Russia, Mongolia, China and Kazakhstan. The cave was occupied by humans for 125,000 years and a variety of stone tools and bones have been recovered. The size of the bone has led scientists to believe it came from a child, aged between five and seven, though they are unable to say whether it was male or female. Scientists at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, ran genetic tests on the bone fragments and were stunned to find it did not match the DNA profile of Neanderthals or early modern humans.Johannes Krause sequenced DNA from mitochondria, the sub-cellular bodies that carry genetic material passed down only the maternal line. Because the DNA came from the mother, they called the creature "X-woman". "It really looked like something I had never seen before. It was a sequence which is similar in some ways to humans, but still quite distinct," Krause said. It is the first time a new type of human has been identified from DNA alone. By comparing the DNA with sequences from Neanderthals and modern humans, Krause's team concluded that modern humans shared a common ancestor with the creature a million years ago. Humans and Neanderthals diverged from an ancestor that lived 500,000 years ago. When Krause saw the results of the genetic test, he called project leader Svante Pääbo. "It was absolutely amazing, I didn't believe him. I thought he was pulling my leg," Pääbo said. The bone fragments were recovered from a layer of rock in the cave dated to between 48,000 and 30,000 years ago. The first humans to move from Africa to Eurasia were Homo erectus 1.9m years ago, but scientists believed they died out around 100,000 years ago. The new species probably migrated from Africa more recently, around 1m years ago, and survived in Eurasia until at least 40,000 years ago. Krause's team is now analysing DNA from the nuclei of cells in the finger fragments in the hope of locating the species in the human family tree. The tests should also indicate whether there was any interbreeding between the new species, Neanderthals and modern humans. "There were at least three different forms of humans in the area between 30,000 and 40,000 years ago, and there were also the hobbits in Indonesia, so the picture of what was around in human form in the late Pleistocene gets a lot more complex and a lot more interesting," Pääbo said. Chris Stringer, head of human origins at the Natural History Museum in London, said: "This new DNA work provides an entirely new way of looking at the still poorly understood evolution of humans in central and eastern Asia." guardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds Source: Science news, comment and analysis | guardian.co.uk | 24 Mar 2010 | 1:19 pm Universe Has Billions More Stars Than ThoughtCounting all of those twinkling lights in the night sky just got a lot harder.Source: Discovery News - Top Stories | 24 Mar 2010 | 1:15 pm Italian swaps physics for writing and wins plauditsNEW YORK (Reuters) - Working long days in a particle physics laboratory at the University of Turin, doctoral student Paolo Giordano wanted an escape from the academic rigors of numbers.Source: Reuters: Science News | 24 Mar 2010 | 1:11 pm New Method Could Revolutionize Dating of Turin ShroudThe Shroud of Turin, the controversial piece of linen that some believe to be the burial cloth of Jesus Christ, could finally be dated accurately. A new method "stands to revolutionize radiocarbon dating," according to a new research.Source: Discovery News - Top Stories | 24 Mar 2010 | 12:48 pm X-Woman Could Forever Change Human HistoryToday's news about X-Woman, an unknown hominin that coexisted with Neanderthals and our species 30,000 to 50,000 years ago, suggests that at least four different forms of humans were in Europe and Asia after Homo sapiens migrated out of Africa. ...Source: Discovery News - Top Stories | 24 Mar 2010 | 12:33 pm Global Warming Ends Border DisputeA 30-year-long argument between India and Bangladesh has ended in a draw.Source: Discovery News - Top Stories | 24 Mar 2010 | 12:20 pm Possible new human ancestor found in SiberiaWASHINGTON (Reuters) - Genetic material pulled from a pinky finger bone found in a Siberian cave shows a new and unknown type of pre-human lived alongside modern humans and Neanderthals, scientists reported on Wednesday.Source: Reuters: Science News | 24 Mar 2010 | 12:09 pm 'X-Woman' Coexisted With Neanderthals, Modern HumansA newly discovered human species likely wore heavy clothing and bracelets and hunted large game.Source: Discovery News - Top Stories | 24 Mar 2010 | 12:00 pm Riyadh says arrests militants planning oil attacks (Reuters)Reuters - Saudi Arabia said on Wednesday it had arrested 113 al Qaeda militants including suicide bombers who had been planning attacks on energy facilities in the world's top oil exporter.Source: Yahoo! News: Science News | 24 Mar 2010 | 11:54 am More Greenland Ice Melting FasterSensitive Global Positioning System and other satellite-borne sensors have detected the accelerating northwestern migration of ice loss the length of coastal Greenland since 2005. Scientists have known for some time that the great ice sheet was losing mass over southeastern ...Source: Discovery News - Top Stories | 24 Mar 2010 | 11:27 am Chemical From Plastic Water Bottles Found Throughout Oceans
A survey of 200 sites in 20 countries around the world has found that bisphenol A, a synthetic compound that mimics estrogen and is linked to developmental disorders, is ubiquitous in Earth’s oceans. Bisphenol A, or BPA, is found mostly in shatter-proof plastics and epoxy resins. Most people have trace amounts in their bodies, likely absorbed from food containers. Its hormone-mimicking properties make it a potent endocrine system disruptor. In recent years, scientists have moved from studying BPA’s damaging effects in laboratory animals to linking it to heart disease, sterility and altered childhood development in humans. Many questions still remain about dosage effects and the full nature of those links, but in January the U.S. Food and Drug Administration announced that “recent studies provide reason for some concern about the potential effects of BPA on the brain, behavior, and prostate gland of fetuses, infants and children.”
The oceanic BPA survey, presented March 23 at an American Chemical Society meeting in San Francisco, was conducted by Nihon University chemists Katsuhiko Saido and Hideto Sato. At an ACS meeting last year, they described how soft plastic in seawater doesn’t just float or sink intact, but can break down rapidly, releasing toxins. In their new findings, they showed that BPA-containing hard plastics can break down too, and found BPA in ocean water and sand at concentrations ranging from .01 to .50 parts per million. As for what those numbers mean for public and environmental health, it’s hard to say. BPA can cause reproductive disorders in shellfish and crustaceans, and doses below a single part per trillion can have cell-level effects, but the path from water and sand to ocean animals needs to be studied. One disturbing possibility is that BPA could bioaccumulate, with animals eating BPA-tainted animals that have eaten BPA-tainted animals, finally reaching high concentrations in top-level ocean predators and the humans who eat them. For that to happen, BPA would have to be stored in fatty tissue, rather than passing quickly through the body. “That’s a really difficult, unsettled question,” said Shanna Swan, a University of Rochester environmental medicine specialist who wasn’t involved in the survey. In a 2009 Environmental Health Perspectives study of BPA concentrations in people who had recently fasted, Swan found that BPA levels remained high longer than expected. It’s possible that BPA indeed accumulated in their fat, said Swan. They could also have picked up BPA from as-yet-unappreciated non-dietary sources, such as household dust or leaching from PVC water pipes. Or both scenarios may be true. The BPA contamination found by Saido and Sato likely comes from a mix of boat paint and plastic. About three million tons of BPA-containing plastics are produced each year. The United Nations estimates that the average square mile of ocean contains 46,000 pieces of plastic trash. “Marine debris plastic in the ocean will certainly constitute a new global ocean contamination for long into the future,” wrote Saido and Sato in their presentation. Image: Polihale/Wikipedia See Also:
Brandon Keim’s Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.
Source: Wired: Wired Science | 24 Mar 2010 | 11:18 am By 7 Months, Baby Knows Your MoodsBabies as young as 7 months old already process happy and angry voices in ways analogous to the adult brain.Source: Livescience.com | 24 Mar 2010 | 11:02 am Researchers dig up controversy in JerusalemJERUSALEM (Reuters) - Archaeologists in Jerusalem are competing to unearth artifacts pointing to the ancient city's Jewish past, which are used to justify Israel's claim to all of it as the indivisible capital of the modern Jewish state.Source: Reuters: Science News | 24 Mar 2010 | 10:53 am 7 Great Dramas in Congressional HistoryThe controversial and historic health care vote March 21 was a landmark moment. But where does it rank amongst other government clashes?Source: Livescience.com | 24 Mar 2010 | 10:49 am It’s True: Hot Water Really Can Freeze Faster Than Cold Water
Hot water really can freeze faster than cold water, a new study finds. Sometimes. Under extremely specific conditions. With carefully chosen samples of water.
The Mpemba effect is named for a Tanzanian schoolboy, Erasto B. Mpemba, who noticed while making ice cream with his classmates that warm milk froze sooner than chilled milk. Mpemba and physicist Denis Osborne published a report of the phenomenon in Physics Education in 1969. Mpemba joined a distinguished group of people who had also noticed the effect: Aristotle, Francis Bacon and René Descartes had all made the same claim.
On the surface, the notion seems to defy reason. A container of hot water should take longer to turn into ice than a container of cold water, because the cold water has a head start in the race to zero degrees Celsius. But under scientific scrutiny, the issue becomes murky. The new study doesn’t explain the phenomenon, but it does identify special conditions under which the Mpemba effect can be seen, if it truly exists. “All in all, the work is a nice beginning, but not systematic enough to do more than confirm it can happen,” comments water expert David Auerbach, whose own experiments also suggest that the effect does occur. Papers published over the last decade, including several by Auerbach, who performed his research while at the Max Planck Institute for Flow Research in Göttingen, Germany, have documented instances of hot water freezing faster than cold, but not reproducibly, says study author James Brownridge of State University of New York at Binghamton. “No one has been able to get reproducible results on command.” That’s what Brownridge has done. One of his experiments, presented online, repeatedly froze a sample of hot water faster than a similar sample of cool water. Note the word similar. In order for the experiment to work, the cool water had to be distilled, and the hot water had to come from the tap. In the experiment, about two teaspoons of each sample were held in a copper device that completely surrounded the water, preventing evaporation and setting reasonably even temperatures. Freezing was official when sensors picked up an electrical signal created by ice formation. Brownridge heated the tap water to about 100° C, while the distilled water was cooled to 25° C or lower. When both samples were put into the freezer, the hot water froze before the cold water. Brownridge then thawed the samples and repeated the experiment 27 times. Each time, the hot tap water froze first. The experiment worked because the two types of water have different freezing points, Brownridge says. Differences in the shape, location and composition of impurities can all cause water’s freezing temperature — which in many cases is below zero degrees C — to vary widely. With a higher freezing point, the tap water had an edge that outweighed the distilled water’s lower temperature. Because the experiment didn’t compare two identical samples of water, the mystery of the Mpemba effect is not really solved. “I’m not arrogant enough to say I’ve solved this,” Brownridge says. But he has set some guidelines about when the effect can be seen. Physical chemist Christoph Salzmann of the University of Durham in England says he’s not convinced the Mpemba effect really exists, because there are innumerable things that influence the timing of freezing, making it impossible to completely control. Predicting how long it will take for a water sample to crystallize “is a bit like trying to predict when the next earthquake or crash of the stock market will happen,” he says. “I would not want to say that the Mpemba effect does not exist. But I have still not been convinced of its existence.” Image: Kenn Wilson/flickr
Source: Wired: Wired Science | 24 Mar 2010 | 10:47 am New Contact Lenses Pack Vitamin E, Could Replace Eye DropsA new contact lens loaded with vitamin E could do away with eye drops.Source: Livescience.com | 24 Mar 2010 | 10:45 am Light Bends Matter, Surprising ScientistsLight can twist matter, according to a new study that observed ribbons of nanoparticles twisting in response to light.Source: Livescience.com | 24 Mar 2010 | 10:26 am Maths genius urged to take prizeRussian maths genius Grigory Perelman, who declined a top award four years ago, is under new pressure to accept a prize.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 10:05 am Venomous Snake 'Olympics' Held in AustraliaVenomous snake competitions were recently held in Australia, according to a new study that describes the events: sprint trials in a racetrack, tongue flicking, thrashing, biting when held, and wrapping around other bodies. (Broad-Headed Snake; Credit: berichard) The goal wasn't ...Source: Discovery News - Top Stories | 24 Mar 2010 | 10:04 am GM Cars to Get F-16 Fighter Jet Display TechnologyGM is testing a head-up display (HUD) system for cars that will give drivers the same kind of all-weather, day or night, awareness of their environment that military pilots have today.Source: Livescience.com | 24 Mar 2010 | 9:51 am Study Reveals Who Stresses MostGender and age affect how we respond to stress.Source: Livescience.com | 24 Mar 2010 | 9:30 am Why Overweight Women Struggle to Slim DownObese and overweight middle-aged women don't appear to get the same benefits from exercise as those who are normal weight, research suggests.Source: Livescience.com | 24 Mar 2010 | 8:55 am Forests expert officially complains about 'distorted' Sunday Times articlePress Complaints Commission told that newspaper story gives impression that IPCC made false Amazon rainfall claim A leading scientist has made an official complaint to the Press Complaints Commission over an "inaccurate, misleading and distorted" newspaper story about a supposed mistake made by the UN's panel on global warming. Simon Lewis, an expert on tropical forests at the University of Leeds, says the story, published by the Sunday Times in January, is wrong and should be corrected. He says the story is misleading because it gives the impression that the Intergovernmental Panel on Climate Change (IPCC) made a false claim in its 2007 report that reduced rainfall could wipe out up to 40% of the Amazon rainforest. The Sunday Times story was widely followed up across the world, and, in the wake of the discovery of a high-profile blunder by the IPCC over the likely melting of Himalayan glaciers, helped fuel claims that the IPCC was flawed and its conclusions unreliable. Lewis said: "There is currently a war of disinformation about climate change-related science, and my complaint can hopefully let journalists in the front line of this war know that there are potential repercussions if they publish misleading stories. The public deserve careful and accurate science reporting." The Sunday Times piece was originally headlined "UN climate panel shamed by bogus rainforest claim", though this was later changed on the website version. It said the 40% destruction figure was based on an "unsubstantiated claim by green campaigners who had little scientific expertise". The IPCC report attributed the claim to a report from campaign group WWF, which contained no reference to back the statement. Lewis said he was contacted by the Sunday Times before the article was published and told them the IPCC's statement was "poorly written and bizarrely referenced, but basically correct". He added that "there is a wealth of scientific evidence suggesting that the Amazon is vulnerable to reductions in rainfall". He also sent the newspaper several scientific papers that supported the claim, but were not cited by that section of the IPCC report. Lewis says in his PCC complaint that he told The Sunday Times "the IPCC statement itself was scientifically defensible and correct, merely that [it used] the incorrect reference... To state otherwise is to materially mislead the reader." Lewis also complains that the Sunday Times used several quotes from him in the piece to support the assertion that the IPCC report had made a false claim. "Despite repeatedly stating to the Sunday Times that there is no problem with the sentence in the IPCC report, except the reference." Lewis said he made the PCC complaint, which runs to 31 pages, only after other attempts to raise his concerns failed. A letter to the Sunday Times, he says, was not acknowledged or printed, and a comment he posted on its website was deleted. "As a professional scientist I have to clear this mess up, it's important to protect my reputation in terms of providing accurate scientific information to the public." The Sunday Times said it that printed two letters in response to the article. It said it was "currently dealing with Simon Lewis's complaint and hope to resolve the issue". guardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds Source: Science news, comment and analysis | guardian.co.uk | 24 Mar 2010 | 8:28 am Disputed island sinks below wavesNew Moore in the Sunderbans falls victim to rising sea levels caused by global warming For nearly 30 years, India and Bangladesh have argued over control of a tiny rock island in the Bay of Bengal. Now rising sea levels have resolved the dispute for them: the island has gone. New Moore island in the Sunderbans has been completely submerged, said oceanographer Sugata Hazra, a professor at Jadavpur University in Kolkata. Its disappearance has been confirmed by satellite imagery and sea patrols, he said. "What these two countries could not achieve from years of talking has been resolved by global warming," said Hazra. Scientists at the school of oceanographic studies at the university have noted an alarming increase in the rate at which sea levels have risen over the past decade in the Bay of Bengal. Until 2000, the sea levels rose about 3mm (0.12 inches) a year, but over the last decade they have been rising about 5mm annually, he said. Another nearby island, Lohachara, was submerged in 1996, forcing its inhabitants to move to the mainland, while almost half the land of Ghoramara island was underwater, he said. At least 10 other islands in the area were at risk as well, Hazra added. "We will have ever larger numbers of people displaced from the Sunderbans as more island areas come under water," he said. Bangladesh, a low-lying delta nation of 150 million people, is one of the countries worst affected by global warming. Officials estimate 18% of Bangladesh's coastal area will be underwater and 20 million people will be displaced if sea levels rise one metre by 2050 as projected by some climate models. India and Bangladesh both claimed the empty New Moore Island, which is about two miles long and 1.5 miles wide. Bangladesh referred to the island as South Talpatti. There were no permanent structures on New Moore, but India sent some paramilitary soldiers to its rocky shores in 1981 to hoist its national flag. The demarcation of the maritime boundary – and who controls the remaining islands – remains an open issue between the two south Asian neighbours, and the disappearance of the island does nothing to resolve it, said an official in India's foreign ministry, who spoke on condition of anonymity because he was not authorised to speak on international disputes. guardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds Source: Science news, comment and analysis | guardian.co.uk | 24 Mar 2010 | 8:01 am Pregnancy Hormones May Cause Memory ProblemsMemory problems in pregnant women could be linked to higher hormone levels, study suggests.Source: Livescience.com | 24 Mar 2010 | 7:59 am Bay of Bengal island 'disappears' under the wavesGlobal warming claims a tiny island disputed by India and Bangladesh in the Bay of Bengal, scientists say.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 6:43 am Project to turn CO2 into car fuelScientists and engineers in Bath and Bristol aim to convert carbon dioxide into car fuel.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 6:21 am New cryptic gecko reveals itselfA new and extremely well camouflaged species of gecko in discovered hiding in the mountain forests of Cambodia.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 6:14 am Dinosaur fossilised in sand duneA close dinosaur relative of the biggest animals to ever walk the Earth seems to have been caught in a falling sand dune.Source: BBC News | Science & Environment | UK Edition | 24 Mar 2010 | 3:14 am
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This curious sequence was extracted from a piece of finger bone unearthed in 2008 at Denisova Cave in southern Siberia’s Altai Mountains. Previous excavations of stone and bone artifacts in the cave indicated that modern humans and Neandertals lived there periodically beginning at least 125,000 years ago. Few fossils have turned up at the site.
