TOP 100 SCIENCE SITES
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| Facial cancer hits Tasmanian devil Cedric A Tasmanian Devil who experts hoped was immune to a facial cancer that threatens the marsupial species is euthanised after developing tumours. bbc.co.uk |
Gamers 'better decision makers' Research has shown that action video game fans are better at making quick, accurate decisions than non-gamers. bbc.co.uk |
Letters: A Taste for Peppers (2 Letters) Letters to the editor. feeds.nytimes.com |
White Horse of Uffington is a dog, claims vet Animal expert says 3,000-year-old Oxfordshire landmark may have to be renamedIt is one of Britain's most-loved ancient hill figures, careering across the downland. Now vets are being urged to question whether the White Horse of Uffington was meant to be a horse at all.Challenging the traditional description of the Oxfordshire landmark, retired vet Olaf Swarbrick asks whether the "beautiful, stylised" figure might instead be a dog such as a greyhound or wolfhound.In a letter to the Veterinary Record, his profession's journal, the former cattle and poultry specialist suggests a canine origin for the 110-metre by 38.5-metre animal, which was carefully dug into the downland. He invites alternative theories, too.Swarbrick says: "Looking at it again, it seems that it is not a horse at all: the tail and head are wrong for a horse and more suggestive of a dog. It appears more like a large hound at full stretch. I thought it may be a greyhound, but an anthropologist suggests it is a wolfhound, which (assuming it is not a horse) makes more sense."The horse, if it is one, is about 3,000 years old, dating from 1250-850BC if most recent theories are correct. It was earlier believed to have Anglo-Saxon origins, and perhaps to be a memorial to King Alfred's victories over the Danes in the ninth century AD. Doubts over its equine origin have been aired before but written records suggest the hill on whose slopes it gallops has been named after the white horse since at least the 11th century.Swarbrick told the Guardian: "I was just saying it was not a horse which will perhaps infuriate some archaeologists." If colleagues agreed with him, "quite a lot of people, including the Ordnance Survey, will have to change their terminology".He added that other horse hill figures in Britain were "quite clearly horses", even if more recent than the Uffington one. And the Long Man of Wilmington in Sussex and Cerne Abbas giant in Dorset were clearly human.Keith Blaxhall, the National Trust warden for the area, was not convinced. "I think we all think it is a horse," he said, adding that coins from roughly the same period show a similar stylised horse and chariot. "Horses were enormously important. It signified power. You were mobile."I have always called it a he, for some reason. There is no 'stallion effect' to it but it is a very proud and powerful symbol on the landscape." There had been claims it might be St George's white charger, he said, but the figure long predated his era. The dog suggestion was new to him. "I have really only heard the theory it is feline because of its sinuous design."Blaxhall was unworried by the site's equine symbolism being doubted. "It is different things to different people. Who is really to know? It is prehistory. No one wrote anything down. It is just a magical place and people are drawn to it."ArchaeologyJames Meikleguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
The Physics of Wet Dogs Dog owners no longer have to lay awake at night, wondering how rapidly a wet dog should oscillate its body to effectively shed water onto its favorite human. Presumably, dogs already know, and now, thanks to slo-mo photography, physicists know, tooDog owners no longer have to lay awake at night, wondering how rapidly a wet dog should oscillate its body to effectively shed water onto its favorite human. Presumably, dogs already know, and now, thanks to slo-mo photography, physicists know, too. Which means that everyone who is taking physics courses should pay particular attention to this video because your professor is going to ask you to explain this on your upcoming final exam. Drying of wet fur is critical to mammalian heat regulation. In this fluid dynamics video, a Georgia Institute of Technology research team captures how rapidly hairy/furry mammals must oscillate their bodies when shaking to shed water droplets. High-speed videography and fur-particle tracking shows the angular position of the animal's shoulder skin as a function of time. X-ray cinematography is used to track the motion of the skeleton. The team found that hairy mammals shake their bodies to remove water at frequencies between 4 and 30 Hz, with smaller mammals shaking faster than larger ones: a mouse shakes at 27 Hz, a rat at 18 Hz, a labrador retriever at 4.3 Hz, while a grizzly bear shakes at 4Hz. "Shake frequencies asymptotically approach 4Hz as animals grow in size," they conclude.Not surprisingly, they also found that the looseness of the animal's skin increases the amplitude and speed of shaking. "[It's] nature's analogy to the spin cycle of a washing machine," the authors write. Interestingly, the best fit for this data is not R^0.5 as they predicted. Instead the universal rule for shaken fur is that the frequency increases with R^0.75, suggesting that their model is missing an important correction factor."Perhaps the fur makes a difference?" the team proposes in their video. Sources:Andrew Dickerson, Grant Mills, Jay Bauman, Young-Hui Chang, & David Hu (19 October 2010). The Wet-Dog Shake. Fluid Dynamics : arxiv.org/abs/1010.3279Downloadable video: arxiv.org/src/1010.3279v1/ancAdditional information: the physics arXiv blog.GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |