| Ants use landmarks to navigate, study finds Ants travelling along a familiar route use their photographic memory to calculate how to stay on track, British researchers say. abc.net.au |
Better coordination needed in US tsunami warnings By RANDOLPH E. SCHMID 2010-09-17T19:00:22ZWASHINGTON (AP) -- The U.S. system to warn about giant waves has improved since the deadly Indian Ocean tsunami in 2004, but more work lies ahead, according to an analysis that noted at least one instance when alerts from centers in Hawaii and Alaska appeared to contradict each other.... hosted.ap.org |
Taser firm loses licence after Raoul Moat stand-off Pro-Tect stripped of right to import and sell stun guns after supplying weapons direct to police rather than Home OfficeThe Home Office licence of the company that supplied the Tasers used during the standoff with gunman Raoul Moat was revoked today by the home secretary .The Home Office said the company involved, Pro-Tect systems, had breached its licence by supplying X12 Tasers directly to the police. The licence only gave the firm permission to supply the stun guns to the Home Office's science and development branch for testing.The Home Office also said Pro-Tect breached "rules governing the secure transport of the devices and ammunition".The move means that Pro-Tect, the only supplier of Tasers in the UK, will no longer be able to import and sell the devices.The decision followed media reports that the Tasers fired at Moat during the six-hour standoff in Rothbury, Northumberland, were not licensed. The gunman's death brought the standoff to an end.Moat was on the run last July after shooting his former girlfriend, Samantha Stobbart, 22, killing her boyfriend, Chris Brown, 29, and blinding PC David Rathband, 42.Northumbria firearms officers fired two Tasers at the former nightclub doorman in an "effort to stop him taking his own life", the inquest into his death was told.James Brokenshire, the Home Office minister, said in a letter to the Commons home affairs select committee that short-term authority had been granted to allow Pro-Tect to dispose of its remaining stock. "You will wish to know that we are working with Acpo [the Association of Chief Police Officers] to ensure that police forces continue to have adequate Taser stocks to cover any transition."The Home Office said it was satisfied that the company had supplied Tasers and ammunition to Northumbria police and another police force contrary to its authority. There was no suggestion that firearms officers were at fault.A Home Office spokesman said: "Inquiries following the Raoul Moat operation revealed Pro-Tect breached its licence by supplying Tasers direct to police … The inquiries carried out by Northamptonshire police also revealed the company breached rules governing the secure transport of the devices and ammunition. Faced with these breaches, the home secretary has decided to revoke Pro-Tect's licence to supply Tasers."The X12 Taser is fired from a 12-gauge shotgun and was being tested by the Home Office before being approved for use by police forces in England and Wales.The Home Office stressed that the police could use any weapon they saw fit as long as its use was lawful, reasonable and proportionate.The Independent Police Complaints Commission investigation into the circumstances of Moat's death is continuing. An IPCC spokesman said that it was looking into the acquisition, authorisation and deployment of the XRep Tasers from a police perspective. The licensing of weapons, however, was a matter for the Home Office, he said.Amnesty International said it was seriously concerned that the Taser appeared to have been used without going through the official weapons testing and approval process. "The Taser XRep is a potentially lethal weapon which fires electric shock bullet-like capsules from a standard 12-gauge shotgun or the new-style Taser weapon," said Oliver Sprague, for Amnesty. "It can send up to 20 seconds of the same intense and debilitating pain as the traditional Taser. The traditional Taser sends five seconds of electric shock."Raoul MoatPoliceWeapons technologyArms tradeAlan Travisguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Private spaceship makes first solo glide flight By 2010-10-11T03:51:23ZMOJAVE, Calif. (AP) -- Virgin Galactic's space tourism rocket SpaceShipTwo achieved its first solo glide flight Sunday, marking another step in the company's eventual plans to fly paying passengers.... hosted.ap.org |
How the leopard got its spots A new study shows why leopards and other big cats are spotted, striped or melanistic -- all black. In short, big cats' patterning and pattern attributes evolved in relation to their ecology and behaviors.The Amur leopard, Panthera pardus orientalis, is one of the rarest leopards in the world. Image: Desktop Wallpaper-s (Felidate). Similar to one of Rudyard Kipling's Just So Stories, which used the language of delight to explain natural phenomena, British codebreaker and computer scientist Alan Turing used the language of mathematics to explain his observation that Fibonacci numbers could be seen in plant growth patterns (watch this lovely video to get an idea of what I am talking about). The equation that Dr Turing used? The reaction–diffusion model system. The reaction–diffusion equation is a mathematical model that describes how the concentration of one or more substances changes either because the substances are transformed from one into the other due to local chemical reactions, or because the substances have diffused too far away from each other to chemically interact. Based on this brief description, it doesn't take a genius to realize that reaction–diffusion systems are widely used in chemistry. This model was one of several that I used to learn about water chemistry while an undergrad. However, this system can also be applied to dynamic processes that do not involve chemistry at all; processes such as those found in geology, physics and surprisingly, even in biology and ecology. In fact, Dr Turing's work helped to inspire the field of mathematical biology. Dr Turing first published a paper in 1952 that used reaction–diffusion systems to describe pattern formation and morphogenesis in living things. In that seminal paper, Dr Turing outlined the basic mechanics of reaction–diffusion systems (Turing, A. M. (1952). The Chemical Basis of Morphogenesis. Philosophical Transactions of The Royal Society of London, series B 237: 37-72 [free PDF]). In short, reaction–diffusion systems that are used in biological patterning have basic chemical principles at their core.Two other scientists, Ortolani (DOI: 10.1111/j.1095-8312.1999.tb01942.x) and Ortolani & Caro, later followed up, adding a little more data to the puzzle by suggesting that reaction–diffusion systems might explain leopard spots. But even though Kipling asked long ago why the leopard is spotted, and suggested that leopard spots are related to the big cat's habitat preferences, this hypothesis has not been tested rigorously. But scientific insights provide a mechanism for testing this hypothesis. Building on Ortolani and Ortolani & Caro's earlier, preliminary work, University of Bristol graduate student Will Allen and his advisors wanted to test the hypothesis that the reaction–diffusion equation could be used to understand the interaction between felid coat patterns and the visual appearance of their habitats. To do this study, Mr Allen used the reaction-diffusion model to generate patterns, which varied on several dimensions (regular to irregular; simple or complex; small to large patterns -- see Figure 1) and then asked five volunteers to match coat patterns for 35 species of felidae to these images. Comparing felid coat patterns to these images, nine of the 35 cats were always classified as plain, 16 were always classified as patterned whilst the classifications for 10 showed some variability, mainly relating to pattern polymorphisms. Four of the patterned cats were always judged to have complex patterns, with eight other species occasionally were classed as complex. The coat pattern data (photo and pattern images) were then mapped onto a phylogenetic tree for the felidae (Figure 2). As you can see, these data indicate that patterning emerges or disappears frequently in this family. The same is true of the irregularity of patterning and, to a lesser extent, the complexity of patterning. These features are prevalent in the big cats, the bay cat and the ocelot lineages:The take-home lesson shown by the above data is that many aspects of coat patterning evolves quickly in cats. But what affects this evolution?The team added ecological and life history information to their analyses, and found that arboreal life -- spending a lot of time in trees -- particularly when those trees are located in dense forests, was strongly related to complex patterns. Interestingly, nocturnal activity patterns were not related to the likelihood that a species is patterned but, among patterned cats, those with irregular patterns were more likely to be more active at night. Also interesting was the team's finding that so-called "black panthers" (melanistic cats) were more common in felids with stronger preferences for temperate forests as well as in cats that are habitat generalists -- such as leopards and jaguars. Habitat generalists have access a large number of environmental niches, so unusual colour morphs are more likely to find and excel in a particular niche. "For black cats, this could be hunting in especially dense forest or at night," wrote Mr Allen in an email. This process, known as disruptive selection, allows unusual morphs to increase their numbers and to become fixed, thereby dividing a given population into two distinct groups. In the case of leopards or jaguars, this means that the cats are either spotted or melanistic. In short, these findings explain why you'll never see an all-black cheetah, because cheetahs are grassland specialists. But what is the value in confirming an assertion that Kipling made before most of us were born? First, these findings demonstrate that evolved traits (pattern, habitat and behaviour) can be linked to a mathematical model of pattern development, as Dr Turing suggested. This provides scientists with another tool for making and testing predictions about how evolution is constrained by other unrelated factors, such as development and ecology. Are there plans to study colour patterns in other animals, like giraffes, okapi and zebras?"When this research was in its very initial stages we had in mind to look at patterning in all mammals before realizing what a stupendous undertaking this would have been," said Mr Allen. "I think extending conclusions to species with such different life-histories is difficult -- comparing the function of patterning on a solitary hunter to a herding prey species is problematic," Mr Allen explained, adding that other labmates are studying the function of zebra stripes. "Cats attracted us as an interesting taxa to make initial forays and develop new methods on, as they have a beautiful variety of patterning, which we were already quite confident wasn't related to sexual or social signaling."Mathematical models of pattern development have been applied to other taxa with interesting patterns, such as snakes (DOI: 10.1016/S0022-5193(05)80310-8) and fish (DOI: 10.1046/j.1365-2443.2002.00543.x), and future studies could be designed to link this work with ecology and behaviour. "[W]hat is important is that our process can account for the range of patterns observed in felids," said Mr Allen, whilst noting that a few species have patterns that general trends do not predict."Approaches like the one we took really highlight unusual animals, which so often merit further investigation and lead to surprising new insights."Sources:William L. Allen, Innes C. Cuthill, Nicholas E. Scott-Samuel, & Roland Baddeley (2010). Why the leopard got its spots: relating pattern development to ecology in felids. Proceedings of the Royal Society B: Biological Sciences DOI: 10.1098/rspb.2010.1734.Ortolani, A. & Caro, T. M. (1996). The adaptive significance of color patterns in carnivores: phylogenetic tests of classic hypotheses. In Carnivore behaviour, ecology and evolution, vol. 2 (ed. J. Gittleman), pp. 132–188. Ithaca, NY: Cornell University Press. Ortolani, A. (1999). Spots, stripes, tail tips and dark eyes: predicting the function of carnivore colour patterns using the comparative method. Biological Journal of the Linnean Society 67, 433–476. DOI: 10.1111/j.1095-8312.1999.tb01942.x.Will Allen [emails, 18, 21 & 27 October 2010]GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |