December 17, 2005

• Avian Flu, Answers,

  
  
  
  
  
  

  Avian Flu NIH Uses Live Viruses for Bird Flu Vaccine By LAURAN NEERGAARD WASHINGTON – In an isolation ward of a Baltimore hospital, up to 30 volunteers will participate in a bold experiment: A vaccine made with a live version of the most notorious bird flu will be sprayed into their noses. First, scientists are dripping that vaccine into the tiny nostrils of mice. It doesn’t appear harmful – researchers have weakened and genetically altered the virus so that no one should get sick or spread germs – and it protects the animals enough to try in people. This is essentially FluMist for bird flu, and the hope is that, in the event of a flu pandemic, immunizing people through their noses could provide faster, more effective protection than the troublesome shots – made with a killed virus – the nation now is struggling to produce. And if it works, this new vaccine frontier may not just protect against the bird flu strain, called H5N1, considered today’s top health threat. It offers the potential for rapid, off-the-shelf protection against whatever novel variation of the constantly evolving influenza virus shows up next – through a library of live-virus nasal sprays that the National Institutes of Health plans to freeze. “It’s high-risk, high-reward” research, said Dr. Brian Murphy, who heads the NIH laboratory where Dr. Kanta Subbarao is brewing the nasal sprays – including one for a different bird-flu strain that appeared safe during the first crucial human testing last summer. “It might fail, but if it’s successful, it might prevent hundreds of thousands of cases” of the next killer flu, Murphy said. FluMist is the nation’s nasal-spray vaccine that prevents regular winter flu. Developed largely through Murphy’s lab, it’s the only flu vaccine made with live but weakened influenza viruses. The new project, a collaboration with FluMist manufacturer MedImmune Inc., piggybacks cutting-edge genetics technology onto that vaccine to create a line of FluMist-like sprays against different bird flus. “That is a great, great idea,” said Dr. John Treanor of the University of Rochester, among the flu specialists closely watching the project. Regular winter flu shots are made with killed influenza viruses, and the government is stockpiling experimental bird-flu vaccine made the same way. But those bird-flu shots don’t work as well as hoped. They require an incredibly high dose, delivered in two separate injections, to spark a protective immune response in people. “In theory, a live-virus vaccine might actually work better. We don’t know that because we’ve never tried one before,” Treanor said. Influenza is like a magician, constantly changing its clothes to avoid detection, thus making it difficult to develop effective vaccines. Studding the virus’ surface are two proteins called hemagglutinin – the H in H5N1 – and neuraminidase, the “N”. They act as a wardrobe: There are 16 known hemagglutinin versions, and nine neuraminidases. They’re also what triggers the immune system to mount an attack, particularly hemagglutinin, the protein the body aims for when it makes flu-fighting antibodies. When people catch the flu, they usually get H1 or H3 flu strains, which their bodies can recognize because variations have circulated among humans for decades. Occasionally, genetically unique strains emerge. Until 1997, H5 strains had never been seen outside of birds. The virus essentially put on a coat that human immune systems didn’t recognize. The result: Since 2003, a particularly strong H5N1 strain has infected more than 130 people in Asia, killing at least 70. H9 and H7 strains also recently have jumped from birds to people, although so far they haven’t been nearly as dangerous. Researchers hope to create at least one live-virus nasal spray for each “H” subtype, a project costing about $16 million of the NIH’s annual $67 million budget for flu vaccine research. “The hemagglutinin is the major protective antigen, so that is what we’re focusing on,” explained Subbarao, a molecular geneticist who heads the project. First on her list are the riskiest known bird flus: H5N1, with human tests planned for April. H9N2, which recently underwent the first round of human testing in an isolation ward at Johns Hopkins Bayview Medical Center. Then an H7 strain, followed by an H6 strain believed to share genes with the H5N1. “By no means are we confident we’re picking the right strain” to make first, because flu mutates so easily, Subbarao cautioned. She chooses vaccine strains from those that U.S. scientists who are monitoring influenza in Asia cull from ducks, chickens and geese, and ship home for research. Subbarao must customize those strains for safe vaccination: First, using a new technique called reverse genetics, she selects genes for bird-flu H and N antigens and removes genetic segments that make them dangerous. Then she adds the remaining gene segments to the regular weakened FluMist virus. Stocks of the custom virus are grown in fertilized chicken eggs. Each is then carefully cracked by hand to drain out virus-loaded liquid that in turn is purified and put into a nasal spray. In a high-security section of the lab, Subbarao dons a biohazard suit and exposes vaccinated mice to various bird flu strains. Then it’s time for human testing – in a hospital isolation ward just in case the weakened virus could infect someone. It shouldn’t, because “those problems don’t exist in FluMist,” said Murphy, citing studies of regular FluMist in day-care centers where youngsters routinely pass viruses back and forth. Some studies have found that people can shed virus shortly after receiving regular FluMist. But, “to spread infection, you’d need much more (virus) than replicates in the nose,” he said. Hopkins researchers gave the first of Subbarao’s vaccine candidates – the H9N2 spray – to 30 volunteers last summer. To be sure they couldn’t spread the virus by coughing or sneezing, the volunteers underwent daily tests of their noses and throats. The vaccine appeared safe. Scientists now are analyzing whether it also spurred production of flu-fighting antibodies, a sign that people would be protected if they encountered the H9N2 strain. Subbarao expects results by February. In April, pending final Food and Drug Administration permission, Subbarao will put an H5N1 spray to a similar test. Here’s the catch: Each flu strain has subtypes. An Indonesian version of H5N1, for example, was recently discovered that differs from a Vietnamese strain on which Subbarao’s nasal spray – and the government’s stockpiled shots – are based. She’s now testing whether her vaccine protects mice against that new Indonesian strain. If a novel flu strain begins spreading among people, how will Subbarao tell if her stored nasal vaccines are a good match to fight it? NIH also will store blood samples from the people who test those sprays. Say a new H9 strain sparks an outbreak. That virus will be tested against those blood samples, and NIH could predict within a day which spray candidates work. If one does, the government could order doses manufactured from that frozen stock; if none do, scientists would have to try to brew a new vaccine. How quickly doses could be manufactured is a different issue. All influenza vaccines, shots or spray, currently are brewed in chicken eggs, a time-consuming process that other research is seeking to improve. “These are research projects,” Murphy stresses – the nasal-spray concept could fail. But he’s optimistic. Live-virus vaccines, he maintains, are better immune stimulators. Story from REDORBIT NEWS: http://www.redorbit.com/news/display/?id=332782 Published: 2005/12/17 12:00:00 CST © RedOrbit 2005

  Answers to Arcane Questions Extra: Does Anything Eat Wasps? ; The Answer to Life’s Most Baffling Questions: Exclusive Extract From the Must-Have Book for Christmas Just four weeks ago, a science book with a print-run of 2,500 was published. Five reprints later, it’s sold 100,000 copies, is number three in the Amazon bestsellers list, and is tipped throughout the book trade to be this year’s essential Christmas read. ‘Does Anything Eat Wasps?’ is a compilation of puzzling queries and informed answers from the Last Word section of the ‘New Scientist’ magazine. Started over a decade ago, the column grapples with everyday science and has a huge following. If you’ve ever wondered why we have eyebrows or pondered the possibility of living on beer alone, this book has the answers to these and many more of life’s smaller questions. Read our exclusive eight-page extract and you’ll also finally discover what likes to have wasps for lunch… Why do geese fly in ‘V’ formations? I read a while ago that there are several competing theories as to why geese fly in a ‘V’ shape. Does anyone know the definitive answer? Bruce Shuler PLYMOUTH, MICHIGAN, US When the lead bird completes a flap of its wings two vortices are shed, one from each wing tip. These vortices consist of a rolling tube of air, the upper portion of which is moving forwards and the lower part rearwards. Should a following bird complete a downward stroke into the top of a vortex, the momentum change of the air caught up in the stroke is much greater than had the vortex not been present. Consequently the lift for a given stroke size is greater, and the following bird needs to do less work. To make use of this phenomenon the following two birds must be behind the wing-tips of the lead bird in a V-formation, and the birds behind them should be similarly placed. This leads to an obvious question: why don’t birds take up the position on the inside wings to form a tree formation? The answer is that they would be subject to vortices on both wings that were not synchronised, making flying difficult. David Mann LONDON Why do millipedes have so many legs? Ever since finding a millipede in my bath, I’ve wondered why this creature has so many legs. What advantage do they provide and how did it get them? Sarah Crew ONGAR, ESSEX Millipedes and earthworms have similar lifestyles. Both burrow in soil, eating dead and decaying vegetation, but they have evolved very different methods for forcing their way through soil. Worms use the strong muscles in their body walls to build up pressure in the body cavity, and so develop the forces needed to push forward or widen a crevice in the soil. Millipedes, however, use their legs to push through the soil. The more legs the animal has, the harder it can push. Millipedes are different from centipedes. They have very large numbers of short legs because long legs would be a liability in a burrow. Centipedes, which spend their time on the surface or among leaf litter, have fewer, longer legs. R McNeill Alexander EMERITUS PROFESSOR OF ZOOLOGY UNIVERSITY OF LEEDS PLANTS AND ANIMALS Does anything eat wasps? In a recent conversation about food chains, a colleague wondered if anything ate wasps. Someone suggested ‘very stupid birds’. Does anyone know any more about this? Tom Eastwood, LONDON The lowly wasp certainly has its place in the food chain. Indeed, the question should possibly be ‘what doesn’t feed, in one way or another, on this lowly and potentially dangerous insect?’ Here are a few that do, the first list being invertebrates: several species of dragonflies (Odonata); robber and hoverflies (Diptera); wasps (Hymenoptera), usually the larger species feeding on smaller species, such as social paper wasps (Vespula maculata) eating V utahensis; beetles (Coleoptera); and moths (Lepidoptera). The following are vertebrates that feed on wasps: numerous species of birds, skunks, bears, badgers, bats, weasels, wolverines, rats, mice and last, but certainly not least, humans and probably some of our closest ancestors. I have eaten the larvae of several wasp species fried in butter, and found them quite tasty. Orvis Tilby, SALEM, OREGON, US Is it dangerous to eat green potatoes? And do similar problems lurk in species related to potatoes, such as yams or aubergines? Emily Jane Horseman, BUXTON, DERBYSHIRE When a potato is exposed to light, its solanine content escalates as a natural protection against being eaten by foraging animals. It is, after all, meant to propagate a new plant rather than be consumed. Solanine gives potatoes a bitter taste and checks the action of the neurotransmitter acetylcholine. This causes dry mouth, thirst and palpitations. At higher doses it can cause delirium, hallucinations and paralysis. The green in a toxic potato is harmless chlorophyll, but it acts as a warning that the potato has an elevated level of solanine. The entire potato should be discarded. The same applies to potatoes that have begun to sprout and to potatoes that show black streaks from late blight. The fatal dose of solanine for an average adult is between 3mg and 6mg per kilogram of body weight, or between 200mg and 500mg in total, depending on body weight. Properly stored potatoes contain less than 200mg per kilogram, so a fatal dose could, arguably, be obtained from as little as 1kg if a person had a small body mass. Solanine is concentrated in the potato skin, so peeling removes between 30 and 90 per cent of this toxin, which runs counter to the old saying that ‘the skin is the best part’. In the past, potatoes were stored unwashed in paper sacks and dumped on the bottom shelf or darkest place in the vegetable store. The modern practice of washing potatoes and packing them in clear plastic increases solanine risk. On exposure to light at 16C the solanine content quadruples every 24 hours. At 75C it can be nine times greater and can reach to 1,800mg per kilogram in the skin. Other nightshades, such as tomatoes, aubergines and capsicums also contain solanine in varying quantities, depending on the degree of ripeness and whether they are infected with blight. Craig Sams, HASTINGS, EAST SUSSEX How big is a mole tunnel network? Is it constantly developing the network and do areas become redundant? How far does the average mole tunnel in its lifetime? And if moles are fiercely solitary, do individual networks overlap? If not, how do they find each other to ensure future mole generations? Alan Rowe, INSCH, ABERDEENSHIRE The depth and extent of a mole’s (Talpa europaea) tunnel system will vary considerably depending on a number of factors, such as the type of soil and the height of the local water table. Earthworms and other invertebrates that enter the tunnel system are the moles’ main source of food, so it is likely that a mole living in a worm-rich meadow will need a less extensive tunnel system than a mole that inhabits a tunnel system in an acidic soil where worm numbers are much lower. Moles do extend their tunnel systems when necessary and they will abandon those that are no longer needed or productive. Their digging activity increases in the autumn when the colder soil temperatures send earthworms (and their mole hunters) deeper below the surface. In the spring, earthworms start to return to the surface layers of the soil and there will be much more mole activity as they begin to make new surface tunnels or repair old ones. Moles are largely solitary animals outside their spring breeding season and they will drive out those of their species that intrude into their tunnel systems. However, in areas where mole populations occur at high densities their tunnels may overlap. During the mating season in February and March, the males become far more mobile and will frequently leave their territories in search of mates. Much of this travelling is done at ground level but they can also make use of existing tunnel systems. Females are probably located by scent, but very little is known about the mating behaviour of moles. Andrew Halstead, PRINCIPAL ENTOMOLOGIST ROYAL HORTICULTURAL SOCIETY, LONDON How do dock leaves soothe nettle rash? And are they effective on any other plant or insect stings? Tim Crow, HIGHNAM, GLOUCESTERSHIRE Being stung by a nettle is painful because the sting contains an acid. Rubbing the sting with a dock leaf can relieve the pain because dock leaves contain an alkali that will neutralise the acid and therefore reduce the sting. Bees and ants also have acidic stings, so dock leaves should help, but other alkalis, such as soap or bicarbonate of soda, are usually better. However, a dock leaf is useless against wasp stings, which contain an alkali. This is unfortunate because wasps are nasty little critters whose sole aim in life is to ruin picnics and barbecues. If you want to neutralise a wasp sting you should use an acid such as vinegar. The only problem is you’ll smell of pickles for the rest of the day. Peter Robinson, LIVERPOOL Will a cat survive a fall from any height? A friend of mine reckons that you can drop a cat from any height and it will survive unhurt because its terminal velocity is lower than the speed at which it can land unhurt. Can someone confirm or refute this, because kittens in my house now look strangely at my friend. I’m sure this can’t be true, can it? Anna Goodman, OXFORD I’m reminded of a study reported in the Journal of the American Veterinary Medicine Association in 1987 by WO Whitney and CJ Mehlhaff, two New York vets, entitled ‘High-rise Syndrome in Cats’. The study was also summarised in Nature a year later. Briefly, the authors examined injuries and mortality rates in cats that had been brought to their hospital following falls ranging from between two and 32 storeys. Overall mortality rates were low, with 90 per cent of the cats surviving, a fact that supports the correspondent’s ailurophobic friend. However, the study unexpectedly found that the incidence of injuries and death peaked for falls of around seven storeys, and then actually decreased for falls from greater heights. The Nature article presents three main variables that determine injury and mortality rate ” the speed reached by the moggy, the distance in which said moggy is brought to a stop, and the area of moggy over which the stopping force is spread. While concrete streets work in nobody’s favour when it comes to stopping falling items, cats suffer relatively little injury (compared to their owners) because they do indeed reach lower terminal velocities and absorb the shock of stopping so much better. A falling cat has a higher surface area to mass ratio than a falling human, and so reaches a terminal velocity of about 100km per hour (about half that of humans). They are also able to twist themselves so that the impact is spread over four feet, rather than our two. And, as they are more flexible than humans, they can land with flexed limbs and dissipate the impact forces through soft tissue. To answer the paradoxical increase in survival rates once seven storeys has been reached, the authors suggested that an accelerating cat tends to stiffen up, reducing its ability to absorb the impact. However, once terminal velocity is reached, there is no longer any net force acting on the cat, and so it will relax, increasing both its flexibility and the cross-sectional area over which the impact is dissipated once the cat hits the ground. I’d still keep your friend away from your kittens, if I were you. Few buildings in your home town of Oxford are seven storeys high, but there are plenty of rivers about. John Bothwell, MARINE BIOLOGICAL ASSOCIATION, PLYMOUTH, DEVON Why do bruises change colour? I can see why bruises would be red or purple, but what accounts for the yellowish-green colour? And why do they often take a day or two to appear? Rick Rossi, BIRMINGHAM A bruise occurs when small capillary blood vessels break under the skin. The haemoglobin in this leaked blood gives the bruise its classic red- purplish hue. The body then ropes in white blood cells to repair the damage at the site of the injury, which causes the red cells to break down. This produces the substances that are responsible for the colour changes. The breakdown products of haemoglobin are biliverdin, which is green, and then bilirubin, which is yellow. Later, the debris at the bruise site clears and the colour fades. Claire Adams, BELMONT, WESTERN AUSTRALIA Bruises sometimes take a long time to appear because the damage can occur deep in the body tissues. The body under the skin is not, of course, an amorphous mass ” it has discrete muscles and organs, separated by planes of fibrous tissue (these can be seen clearly when looking at joints of meat from the butcher). When blood leaks from damaged vessels it is often prevented from reaching the skin’s surface quickly by these planes of tissue, or it may simply take a while to diffuse through subcutaneous tissue. The fibrous tissue sheaths also explain why a bruise occasionally appears some distance from the original impact ” the leaking blood has tracked under the sheath and surfaces only where the fibrous tissue ends. Stewart Lloyd, CONSULTANT OCCUPATIONAL PHYSICIAN, BRIGG, NORTH LINCOLNSHIRE Why do people have eyebrows? Question asked by Ben Holmes, EDMONTON, CANADA My father has alopecia so he doesn’t have eyebrows. In warm weather, sweat runs into his eyes and makes them sore; in wet weather he has to keep wiping the rain out of his eyes. So your eyebrows divert sweat droplets and raindrops from running directly into your eyes. You would be very uncomfortable without them. Valerie Higgins, TELFORD, SHROPSHIRE We use our exceptionally mobile eyebrows to communicate our emotions. The position of the eyebrows emphasises expressions on the human face, thus giving others an accurate picture of the individual’s mood. This gives a good indication of whether a person is friendly or whether they might be dangerous to approach. Alison Venugoban, NGUNNAWAL, ACT, AUSTRALIA How many species live on or in our bodies? And what is the total population of these guests? Roger Taylor, WIRRAL, MERSEYSIDE The microorganisms that inhabit the body of a healthy human being are known as the normal microbial fauna, and they come in two different types ” those that are permanently resident and those that are transient. Of course, any number of fascinating and nasty parasites can join this microbial community and make the human body their home. In his seminal work Life on Man (Secker & Warburg, 1969), bacteriologist Theodor Rosebury gives a full biological and historical account of the microbes that live on the average human. The figures that he grapples with are mind-boggling. For example, he counted 80 distinguishable species living in the mouth alone and estimated that the total number of bacteria excreted each day by an adult ranges from 100 billion to 100 trillion. From this figure it can be estimated that the microbial density on a square centimetre of human bowel is around 10 billion organisms. Microbes inhabit every surface of a healthy adult human that is exposed to the outside, such as the skin, or that is accessible from the outside ” the intestines, from mouth to anus, plus eyes, ears and airways. Rosebury estimates that 10 million individual bacteria live on the average square centimetre of human skin. However, this figure can vary widely throughout the almost 2 square metres that make up the surface area of a human. In the oily skin that is found on the side of the nose or in a sweaty armpit, the figure can increase tenfold, while once inside the body, on the surface of the teeth, throat or alimentary tract, these concentrations can increase a thousandfold. Yet, while the figures appear huge, he estimates that all the bacteria living on the external surface of a human would fit into a medium-sized pea, while all those on the inside would fill a vessel with a capacity of a mere 30Oml. As to the total number of species that are inhabiting a healthy body, estimates vary as more species are discovered on a seemingly regular basis, but Mark Pallen, a professor of microbiology based at the Queen’s University of Belfast, reckons that the figure is in excess of 200. ‘There are more than 80 that live in the mouth alone, and studies that have been carried out at the Unit of Ecology and Physiology of the Digestive System in Jouy-en- Josas, France, suggest that at least another 80 live in the gut, with many others living on our skin. Of course, it’s not just bacteria and viruses that make people their home. In his books Fearsome Fauna (WH Freeman, 1999) and Furtive Fauna (Penguin, 1992), Roger M Knutson describes the wide range of parasites that live on and inside you. These tend to be macroscopic organisms, and some of them can be pretty gruesome creatures. Lice are perhaps the most common of these body dwellers. None the less, they tend to be more itchy than damaging ” unlike ticks, which can cause any number of nasty and exotic diseases from royal farm virus to Omsk haemorrhagic fever. Then there is the scabies mite, which is believed to infest millions of humans worldwide, and is able to burrow into the body to hide itself, causing a nasty itch. Fortunately, its close relative, the follicle mite, which is found on everybody in the world, happily munches dried skin cells and causes far less aggravation. And not all body parasites creep and crawl ” you can find fungi in your hair and mould in your skin folds if you look closely enough. Inside your digestive tract you can, among others, find the protozoan that causes amoebic dysentery, 20-metre beef tapeworms and a hookworm that has a penchant for finding its way into your bloodstream. Other creatures in your blood can include the hermaphroditic Shistosoma worm, which can lead to a bloody and scarred bladder, while in your lymphatic system you may find the 12cm Wucheria worm. In your liver you may come across the bile-loving Clonorchis sinensis fluke and, perhaps most horrifying of all, the brain can house Naegleria fowleri, an amoeba that just loves the warmth it finds inside your skull, reproducing in its millions until you drop down dead. How much does a human head weigh? Obviously, I can measure the volume of my head by simple water displacement, but I can’t tell its density, nor can I work out the weight and density of its various components. Bruce Firsten, MIAMI, FLORIDA, US Measuring the weight of your head involves effectively isolating it from the rest of your body. Decapitation has the obvious disadvantage of you not being alive to see the results. However, there is a solution. Your neck vertebrae are responsible for holding your head’s weight. If you hang upside down from your feet the vertebrae in your neck move apart slightly because of the weight of your head pulling on them. To weigh your head you must simply lower yourself slowly on to a scale while hanging upside down. You continually observe the distance between the top vertebra of your neck and your skull, using, say, an ultrasound scanner, and the instant the vertebra starts moving toward the skull you stop and read the scales. Because your neck is not imparting any force on to your head this isolates your head from your neck, thus giving an accurate measure of your head’s weight. Andy Phelps, BURNHAM-ON-SEA, SOMERSET As a canoeist and kayaker, I remember when learning to do an Eskimo roll that my instructor told me to make sure that however much I needed a breath, the last thing to leave the water as my body emerged should be my head. He said the average human head weighs around 4.5kg. Unfortunately, I found that to be a lot of extra weight to lift clear of the water using only the blade of a paddle! Andy Wells, GRANTOWN-ON-SPEY, HIGHLANDS Does bromide in tea dampen your libido? After a friend complained about the overzealous attentions of a lover, I came across a reference in Paul Ferris’s ‘Sex and the British’ to the use of bromide in tea as a means of curbing soldiers’ sexual appetites. Is this advice I could pass on to my friend? Chloe Dear, EDINBURGH Bromides are used as a sedative. The libido reduction is a side- effect. The use of bromide salts as a sleeping draught appears in the novels of Emile Zola, indicating their effects were recognised at some time in the 19th century. In a reference to using bromides to reduce libido, the comic and author Spike Milligan wrote in Rommel? Gunner Who?: ‘I don’t think the bromide had any lasting effect. The only way to stop a British soldier feeling randy is to load bromide into a 300lb shell and fire it at him from the waist down.’ John Rowland, DERBY How do black trousers make your bum look smaller? I recently remarked to a female friend of mine that a lot of the girls in Swindon wear black trousers and denim jackets. She told me it was because black trousers ‘make your bum look smaller’. Is this true? Can it be scientifically proven? Neil Taylor, SWINDON, WILTSHIRE Yes, your bum does look smaller when you dress in black, at least if viewed from behind. The reason is that we can only perceive shapes if what we see appears in different shades or colours. If one wore white trousers the shape of your behind could be inferred from the slight shadows cast by its contour. In black clothing, the shadows are invisible and the shape appears flat. This is the reason why people with dark skin often seem to age well compared with pale- skinned people. Wrinkles and lines, which are visible mainly by virtue of the fact that they create shadows, are harder to detect on darker skin. It is also the reason why facial features need to be greatly exaggerated on dark bronze sculptures. Of course, your bottom will reveal its true size in profile, but black, especially matt, will save you a lot of exercise and dieting. Glyn Hughes, INDUSTRIAL DESIGNER AND SCULPTOR ADLINGTON, LANCASHIRE Why do ‘pictures’ reappear on mirrors? When condensation forms on a clean bathroom mirror, you can draw pictures in it. When the condensation evaporates, the pictures disappear. But when it forms again, they reappear. Why? Glyn Williams, DERBY When you draw an image in the condensation mist, you leave traces of finger grease (or, if you have just washed, grease plus shampoo or soap). The film is transparent, so you don’t see it when the condensation clears. The next time water vapour condenses on the cold mirror, there is a difference in droplet size between condensation on clean glass and on contaminated glass. In some cases, it is the contaminated glass that encourages droplet formation, and then you see the image as positive rather than negative. But usually water-loving surfactants such as soap reduce the formation of droplets and generate a smoother, clear film of water, contrasting with the grey mist on the surrounding glass. Hugh Wolfson, ALTRINCHAM, CHESHIRE Why do rubber bands spontaneously melt? I find an ageing rubber band on my desk that has turned into a sticky mess. After a few more months, the sticky mass solidifies and becomes brittle. Why? Stuart Arnold, MUNICH, GERMANY Natural rubber is made of polyisoprene chains that slip past each other when the material is stretched. When raw, the substance is too sticky and soft to be of much use, so it is toughened with the addition of chemicals such as sulphur that create cross-links between the chains, making the rubber stiffer and less sticky. This process is called vulcanisation. With time, ultraviolet light and oxygen in the air react with the rubber, creating reactive radicals that snip the polyisoprene chains into shorter segments. This returns the rubber to something like its original state ” soft and sticky. Meanwhile, these radicals can also form new, short cross- links between chains. This hardens the rubber and eventually it turns brittle. Any vulcanisation agents left in the rubber contribute to the process. Whether a rubber band goes sticky or hard depends on the relative rates of these processes, and these rates in turn depend on the rubber’s quality, such as what additives, fillers and dyes it contains ” and how it is stored. The Editor Why are Guinness bubbles white? When I buy a pint of Guinness there is no doubt the liquid is black. Yet the bubbles that settle on top, which are made of the same stuff, are white. The same is true of many types of beer. Why? Stewart Brown, BRISTOL In the interests of science I poured myself a Guinness and waited until the rising bubbles had formed a creamy head. I put a little of this in a dish and examined it through a low-powered microscope. Unlike bath foam, which has many semi-coalesced bubbles, Guinness foam is made mainly of uniformly sized, spherical bubbles of about 0.1mm to 0.2mm in diameter, suspended in the good fluid itself. Near the edge of the drop of foam it was possible to find isolated examples of bubbles, and by viewing objects held behind these it was clear that they were acting as tiny divergent lenses. Just as a clear spherical marble, which has a higher refractive index than the surrounding air, can act as a strong magnifying glass, so spherical bubbles in beer diverge light because the air they contain has a lower refractive index than the surrounding fluid. As a result, light entering the surface of the foam is rapidly scattered in different directions by multiple encounters with the bubbles. Reflections from the bubbles’ surfaces also contribute to this scattering. Some of the light finds its way back to the surface, and because all wavelengths are affected in the same way we see the foam as white. Light scattering from foam is akin to the scattering from water droplets that causes clouds to be white. This is called Mie scattering. I drained the glass. On closer inspection, the head of Guinness is actually creamy coloured, and a drop or two that remained in the bottom of the glass had a light brown colour. Although bulk Guinness appears black, it is not opaque. In the foam there is not so much liquid ” most of the space is taken up by air. But because light is scattered from bubble to bubble the intervening brew does absorb some of it, providing a touch of colour. To ensure reproducibility, the experiment was repeated several times. Martin Whittle, SHEFFIELD Why does runny honey suddenly turn solid? Jars that have remained clear for years can, over the space of a couple of weeks, change into solid sugar while the jar remains motionless on its shelf. Temperature does not seem to be a factor ” the process can occur in winter or in summer. Billy Gilligan, READING, BERKSHIRE Bee-keepers argue about this, as honeys from different sources behave differently. Honey is a supersaturated solution of various proportions of sugars (mainly glucose and fructose), and is full of insect scales, pollen grains and organic molecules that encourage or interfere with crystallisation. Glucose crystallises readily, while fructose stubbornly stays in solution. Honeys like aloe honey, which is rich in glucose and nucleating particles, go grainy, while some kinds of eucalyptus honey stay sweet and liquid for years. Unpredictably delayed crystallisation means a nucleation centre has formed by microbes, local drying, oxidation or other chemical reactions. Crystallisation can also be purely spontaneous, starting whenever enough molecules meet and form a seed crystal. Some sugars do this easily, others very rarely. By seeding honey with crystals, or violently stirring air into it, you can force crystallisation. Products made this way are sold as ‘creamed’ honey. The syrup between the sludge crystals is runnier and less sweet than the original honey, because its sugar is locked into crystals. Gently warm some creamed honey in a microwave until it dissolves, compare the taste of the syrup with the sludge ” you will be astonished. Jon Richfield, SOMERSET WEST, SOUTH AFRICA Which is less environmentally damaging, blue or white loo paper? I always use blue toilet paper because it matches my bathroom decor. However, a friend told me that I should only use white, because coloured paper is more damaging to the environment. My local supermarket sells a huge variety of colours with any number of patterned varieties too. Is it true that some varieties are more environmentally damaging? And if so, why? Is kitchen roll even worse than toilet paper? John Shaw, DRIFFIELD, EAST YORKSHIRE If your friend means that the dyes are ecologically harmful, forget it. Chemically active groups on the dye molecules cling to the cellulose, which is why the colours don’t run and leave you fundamentally decorative after you apply them. The dyes are like a mousetrap that has caught a mouse: the mouse, in demonstrating its bite, has become harmless. Much as the trap is hard to reset, the dyes are hard to release from the paper. Dyes are expensive, and toilet paper requires only traces, so even the most environmentally unaware manufacturer will prefer safe dyes that are simple to handle, and can be applied stingily, typically in parts per million. When the paper reaches the sewage works, the immobilised molecules soon succumb to bacteria, so they do not accumulate in the environment. If you doubt this, buy a job lot of toilet paper, fold wads of say 10 squares, each of a single colour, bury them separately in moist garden soil, and in a month or two exhume them and observe the result. In good soil you will do well even to detect your test pieces after the earthworms have done their work. Much the same applies to kitchen paper, except that its strength while it is wet may mean it breaks down more slowly. Its persistence probably does more to provide bacteria with a durable home than harms the environment in any way. Anyway, what about the bleaches necessary for producing white toilet paper? If you really want to be politically correct, go for garbage grey. Jon Richfield, SOMERSET WEST, SOUTH AFRICA Why is the sea blue? I always believed that the sea looked blue because it reflected the colour of the sky. On holiday in Malta the sea was a very clear, deep azure blue inside caves where there was no reflected sky. What caused this colour? Peter Scott, NORFOLK Seawater appears blue because it is a very good absorber of all wavelengths of light, except for the shorter blue wavelengths, which are scattered effectively. The light attenuation is caused by the combined absorption and scattering properties of everything in the water, along with the water itself. Changes in the sea’s colour are primarily due to changes in the type and concentration of plankton. Tropical oceans are clear because they are lacking in suspended sediment and plankton, which contrasts with the popular misconception that tropical waters have a high biological productivity. In fact, they are virtually sterile compared with the cooler, plankton-rich temperate ocean regions. Inorganic particulates and dissolved matter also reflect and absorb light, which affects the clarity of the water. Johan Uys, BELLVILLE, SOUTH AFRICA Reflection of light contributes to the colour of the open sea, but does not determine it. Even pure water is slightly bluegreen, because it filters out the red and orange content of light. However, impurities in seawater, especially organic substances, affect its appearance far more drastically. In caves like those described, the light coming in must travel through a greater thickness of seawater than the light we usually see. The strong absorption of wavelengths other than blue and green intensifies the ethereal effect. In fact, such light contains so little red that navy personnel who have been on submarine duty for several days find everything looks unnaturally ruddy when they return to the surface. Jon Richfield, SOMERSET WEST, SOUTH AFRICA Why do the equinoxes not always fall on the same date? I was always under the impression that the equinoxes fell on 21 March and 21 September, dividing the year into four equal parts along with the solstices. However, I often read that the equinox will fall on a day other than the 21st. Surely there has to be an equal division of the seasons, relying on the Earth’s orbit around the Sun? What could possibly change this? Kingsly Richard, TOULOUSE, FRANCE The spring and autumn equinoxes are defined as the point in time when the sun is overhead at midday local time on the equator (in astronomical terms, the time at which the sun crosses the celestial equator). On the equinoxes there is an equal length of day and night everywhere in the world. The precise date of the equinoxes varies slightly; in the northern hemisphere the spring equinox usually falls on either 20 or 21 March and the autumn equinox on either 22 or 23 September (in the southern hemisphere the dates are reversed). This variation is simply because some years are leap years, so there is a shift in the calendar of a day or so relative to the seasons. The equinoxes occur on exactly opposite sides of the Earth’s orbit around the Sun, but it is interesting that the dates on which they fall do not divide the year into two equal halves. Take the average dates of the equinoxes and the mean length of the year, and the autumn equinox falls 186 days after the spring equinox, whereas the spring equinox is only 179.25 days after the autumn equinox. This is because the Earth’s orbit is elliptical and the Earth is closest to the Sun in early January. In accordance with Kepler’s second law, which states that a line joining a planet and the Sun sweeps out equal areas in equal intervals of time, this is the part of the year when the angular velocity of the Earth in its orbit is greatest. As a result, the half of Earth’s orbit from the autumn to the spring equinox takes less time to complete than the half between the spring and autumn equinox, when the Earth is further from the sun and moving more slowly. Consequently, spring and summer, during which there are more than 12 hours of daylight, last nearly seven days longer in the northern hemisphere than in the southern. Robert Harvey, Swindon, Wiltshire How much of Britain is taken up by roads? Question asked by Stephen Webb, WEST MERSEA, ESSEX The short answer is that the concrete jungle of roads covers less than 1 per cent of the UK’s surface area. The small size of this amount is particularly apparent when our green and pleasant land is seen from the air. The internet community called Sabre (Society for All British Road Enthusiasts) has been hard at work to arrive at this figure. Our best estimate, derived from various and sometimes conflicting government data, is that there are 425,121km of public roads, comprising 3,589km of motorways, 56,696km of A-roads (of which 7,921km are dual carriageway), 32,850 km of B-roads, 89,686km of C-roads and 242,300km of unclassified roads. Allowing average paved widths of 26 metres for motorways, 18 metres for dual carriageways, 12m for other trunk roads, 8m for B-roads, 4m for C- roads and 3m for unclassified roads, gives a total area of almost 2,200 square kilometres of road. The total area of the UK is usually given as 241,590 square kilometres, so about 0.9 per cent of the land area is road. A rather higher figure, about 1.3 per cent, is sometimes proposed if the total width of land occupied by roads, including verges and hedgerows, is included. This is a less appropriate measure because road verges contribute significantly to wildlife habitat and biodiversity, and cannot seriously be called roads. More detailed statistics can be found in the discussion on the Sabre message boards under the thread ‘road surface area’ at http: //groups.msn.com/TheSABRERoadsWebsite Biff Vernon, MANAGEMENT COMMITTEE MEMBER, SABRE, LOUTH, LINCOLNSHIRE Why does frost on windows make leaf patterns? Question asked by Bob Clarke, NEW MINAS, NOVA SCOTIA, CANADA Waking up to frosty bedroom windows is becoming a thing of the past, thanks to the insulating properties of double glazing and cosy central heating. But if you are still stuck with single glazing, on winter mornings your view will be obscured by fern-like patterns of frost. Panes of glass lose heat quickly on cold nights, cooling the water vapour molecules in the indoor air nearest the glass. The temperature of the water molecules in the air can fall below 0C without them actually freezing. But as soon as this supercooled water vapour touches the cold glass, it turns directly to ice without first becoming water. Tiny scratches on the surface of the glass can collect enough molecules to form a seeding crystal from which intricate patterns then grow. Up close, the crystal surface is rough with lots of dangling chemical bonds. Water vapour molecules latch on to these rough surfaces and crystals can grow quickly. The structure of the elaborate branching depends on the temperature and humidity of the air, as well as on how smooth and clean the glass is. When the air is dry, the water molecules condense slowly out of the air and cluster together in stable hexagons. The six straight sides of these crystals are relatively smooth with very few dangling bonds, giving water vapour molecules little to hang on to. Feather- like patterns are more likely to form on clean windows and when the air is heavy with water molecules. Under these conditions, lots of water vapour molecules bombard the seed crystal and there is no time for the stable hexagons to form. Instead, the molecules latch on to the dangling bonds that stick out of any bumps in the crystal, which means the bumps grow even faster. These bumps eventually grow into large branches, and in turn the bumps on the branches become lacy fronds. The Editor Why do you still feel the sea’s motion after you have got off a boat? When I returned home after a day of sailing lessons, I still had the feeling that the room was moving up and down. Why is this? Richard Matthews (aged 9), OXFORD In order for you to estimate your location, your brain combines information from a variety of sources, including sight, touch, joint position, the inner ear and its internal expectations. Under most circumstances, the senses and internal expectations all agree. When they disagree, there is imprecision and ambiguity about motion estimation, which can result in loss of balance and motion sickness. On boats, seasickness may develop because of conflict between sensory input and internal expectations about motion. Developing ‘sea legs’ is nature’s cure for seasickness: you become accustomed to anticipating the boat’s movements and prepare to adjust your posture accordingly. When you finally go ashore, you may feel your body continuing to do this for hours or even days afterwards, making it seem as if the room is moving and sometimes even leading to nausea. A few unfortunate people experience persistent symptoms lasting months or even years. Exactly why their symptoms persist so long isn’t understood, but they can be treated. Sailing isn’t the only activity that causes illusory motion after-effects. Overnight rail passengers sometimes say they can feel the ‘clickety-clack’ of the track in their legs after they leave the train. And astronauts returning to Earth commonly experience vertigo, nausea, difficulty walking and sensory flashbacks. The longer one is exposed to the unfamiliar motion, the more prominent and long-lasting are the after- effects. Timothy Hain, DEPARTMENT OF PHYSICAL THERAPY AND HUMAN MOVEMENT SCIENCES, NORTHWESTERN UNIVERSITY, CHICAGO, ILLINOIS, US and Charles Oman, MAN VEHICLE LABORATORY, MIT, CAMBRIDGE, MASSACHUSETTS, US For how long can you survive on beer alone? And do different beers ” ale, lager, stout, mild ” confer a better chance of survival? John Eden NARARA, NEW SOUTH WALES, AUSTRALIA Beer has had a reputation since antiquity as being a staple in the diet, often called ‘liquid bread’. In ancient Egypt, workers received beer as part of their salary, as did the ladies-in-waiting of Queen Elizabeth I of England. In 1492, one gallon of beer per day was the standard allocation for sailors in the navy of Henry VII. This high reputation for beer came about because it was made from malted barley, which is rich in vitamins. This is still true today. A quick check using nutritional tables shows that a pint can provide more than 5 per cent of the daily recommended intake of several vitamins, such as B9, B6 and B2, although other vitamins such as A, C and D are lacking. It is of course unethical to conduct an experiment to see whether one can live on beer alone. However, during the Seven Years War of 1756″63, John Clephane, physician to the English fleet, conducted a clinical trial. Three ships were sent from England to America. One ” the Grampus ” was supplied with plenty of beer, while the two control ships ” the Daedalus and the Tortoise ” had only the common allowance of spirits. After an unusually long voyage due to bad weather, Clephane reported that the Daedalus and Tortoise had 112 and 62 men respectively requiring hospitalisation. The Grampus, on the other hand, had only 13, arguably a clear-cut result. Needless to say, the sailors’ allowance of eight pints of beer per day is no longer within the accepted confines of current moderate alcohol consumption. One can only speculate on the state of their livers. Living on beer alone may be a fantasy for some, but it is not a good health strategy. C Walker BREWING RESEARCH INTERNATIONAL, NUTFIELD, SURREY I offer the following answer: I’m 39 and still alive. Chris Jack ST ALBANS, HERTFORDSHIRE Does beheading hurt? And, if so, for how long is the severed head aware of its plight? William Wild OXFORD Yes, beheading hurts. How much depends on the executioner’s skill, or lack of it. When Mary, Queen of Scots, was executed at Fotheringay Castle in 1587, a clumsy headsman gave her three strokes without quite managing to sever her head. The headsman then had to saw though the skin and gristle with his sheath knife before the job could be regarded as complete. The profound, protracted groan Mary gave when the axe first hit left the horrified witnesses in no doubt that her pain was excruciating. Dale McIntyre UNIVERSITY OF CAMBRIDGE A detailed report comes from Dr Beaurieux, who experimented with the head of the murderer Languille, guillotined at 5.30am on 28 June 1905. (From A History of the Guillotine by Alister Kershaw) ‘Here, then, is what I was able to note immediately after the decapitation: the eyelids and lips of the guillotined man worked in irregularly rhythmic contractions for about five or six seconds … I waited for several seconds. The spasmodic movements ceased. The face relaxed, the lids half closed on the eyeballs, leaving only the white of the conjunctiva visible, exactly as in the dying, or as in those just dead. It was then that I called in a strong, sharp voice: ‘Languille!’ I saw the eyelids slowly lift up, without any spasmodic contractions … Next Languille’s eyes very definitely fixed themselves on mine and the pupils focused themselves … After several seconds, the eyelids closed again, slowly and evenly, and the head took on the same appearance as it had had before I called out. It was at that point that I called out again and, once more, without any spasm, slowly, the eyelids lifted and undeniably living eyes fixed themselves on mine with perhaps even more penetration than the first time. Then there was a further closing of the eyelids, but now less complete. I attempted the effect of a third call; there was no further movement and the eyes took on the glazed look which they have in the dead. The whole thing had lasted 25 to 30 seconds.’ Mike Snowden LONDON How fat would you have to be to become bulletproof? Ward van Nostrom BY EMAIL The damage a bullet does is measured in two ways: the depth of penetration and the amount of tissue damage per centimetre of penetration. A 9mm handgun round ” the most common type ” is quoted in The Compendium of Modern Firearms by K Dockery and R Talsorian (Games, 1991) as being able to penetrate approximately 60cms of human flesh before it stops, doing an average of 1 cubic centimetre of damage per centimetre of penetration. In reality the distance penetrated is often much less, because rounds hit bones or pass through the target. This data is also based on a body tissue average. Because fat is about 10 per cent softer and less dense than muscle, the figure of 60cm may be too little. Thomas Lambert BASLOW, DERBYSHIRE Why does lemon juice stop cut apples and pears from browning? Brian Dobson ALTON, HAMPSHIRE To answer this question first we need to understand why some plant tissues go brown when cut. Plant cells have various compartments, including vacuoles and plastids, which are separated from each other by membranes. The vacuoles contain phenolic compounds which are sometimes coloured but usually colourless, while other compartments of the cell house enzymes called phenol oxidases. In a healthy plant cell, membranes separate the phenolics and the oxidases. However, when the cell is damaged ” by cutting into an apple, for example ” phenolics can leak from the vacuoles through the punctured membrane and come into contact with the oxidases. In the presence of oxygen from the surrounding air these enzymes oxidise the phenolics to give products which may help protect the plant, favouring wound healing, but also turning the plant material brown. The browning reaction can be blocked by one of two agents, both of which are present in lemon juice. The first is vitamin C, a biological antioxidant that is oxidised to colourless products instead of the apple’s phenolics. The second agents are organic acids, especially citric acid, which make the pH lower than the oxidases’ optimum level and thus slow the browning. Lemon juice has more than 50 times the vitamin C content of apples and pears. And lemon juice, with a pH of less than 2, is much more acidic than apple juice as a quick taste will tell you. So lemon juice will immediately prevent browning. You could also prevent cut apples browning, even without lemon juice, by putting them in an atmosphere of nitrogen or carbon dioxide, thus excluding the oxygen required by the oxidases. Stephen C Fry INSTITUTE OF CELL AND MOLECULAR BIOLOGY, UNIVERSITY OF EDINBURGH Why is it colder at the South Pole than the North Pole? TP Ladd MIRFIELD, WEST YORKSHIRE Much of the temperature difference between the two poles can be explained by their difference in elevation. The North Pole (monthly average temperatures in winter of around -30C) lies on sea ice on the surface of the Arctic Ocean while the South Pole (at around – 60C) is 2,800 metres above sea level on the ice sheets of the Antarctic continent. The background variation of temperature with height (in Antarctica about -6C per kilometre gain in height) thus accounts for over half the difference. Also, the ‘thinner’ (and hence colder, drier and less cloudy) atmosphere overlying the South Pole reflects less heat back to the surface than its northern counterpart. Much of the remainder of the temperature difference can be explained by the contrasting atmospheric circulation regimes in the two hemispheres. The continents of the northern hemisphere drive quasistationary ‘planetary waves’ in the atmosphere. These waves transport heat polewards and also ‘steer’ mid-latitude depressions into the north polar regions. The continents of the southern hemisphere are smaller and lower than those in the north, so the southern hemisphere planetary waves (and associated heat transport) are smaller. The high mountains of Antarctica also block the poleward movement of mid-latitude depressions, which rarely penetrate into the interior of the continent. Finally, the atmosphere at the North Pole receives some heat from the underlying Arctic Ocean. John King BRITISH ANTARCTIC SURVEY, CAMBRIDGE What would happen if aliens stole the moon? Steven Nairn EDINBURGH The most immediate difference would be the disappearance of the tides. Both the sun and moon influence the tides, but the moon is the dominant force. Remove the moon and the daily rush of the tides would recede to a gentle ripple. The next omen of doom would be wild swings in the Earth’s rotational axis from a position almost perpendicular to the ecliptic plane all the way to being practically parallel to it. These swings would provoke drastic climate changes: when the axis points straight up, each point on the globe would receive a constant amount of heat throughout the year but, when the axis lies parallel to the ecliptic, Earthlings would spend six months sweltering under the unending blaze of the sun, only to spin round and shiver for the next six months, hidden on the frigid surface of the Earth’s dark side. Of all calamities, though, the creature to be pitied first is the marine organism called ‘nautilus’. This mollusc lives in an elegant shell shaped like a perfect spiral partitioned off into compartments. The nautilus only lives in the outermost partition, and each day adds a new layer to its shell. At the end of each month, when the moon has completed one revolution around Earth, the nautilus abandons its current compartment, closes it up with a partition, and moves into a new one. Remove the moon and the nautilus lies stranded, forever locked in the same chamber and wishing ruefully for the days when it could look forward to a new home. Andrew Turpin NEW MOAT, PEMBROKESHIRE Why do dew drops form at the top of grass blades? There have been many times that I have unzipped the flap door on my tent while still in my sleeping bag to see that a heavy dew had fallen during the night. Being so close to the dew-laden grass, I always notice that the individual drops occupy an apparently precarious position at the very tips of grass blades. How do they get there and how do they stay there? John Lamont-Black NEWCASTLE UPON TYNE This process is called guttation. On the surface of leaves there are stomata or pores through which water is lost by transpiration. At night, the stomata close, causing a reduction in transpiration. Drops of water are then forced out of the leaf through special stomata or hydathodes. These special stomata are found along the edges of the leaves or at the tips. It is believed that guttation is caused by high root pressure. Grasses often force water out of the tips of their blades, as your wide-awake camping correspondent noticed. Guttation also happens in potatoes, tomatoes and strawberries on their leaf margins. Frances Tobin MANLY, QUEENSLAND, AUSTRALIA Could you move a large ship by pushing it with your hands? Suppose a large ship, such as the ‘QE2′, is floating freely alongside a quay and no forces such as wind or sea currents are acting on it. If I stand on the quay and push the side of the ship, will it move, even very slowly and slightly? Or is there some sort of limiting friction caused by all those water molecules around the hull that can only be overcome by a much larger threshold force? Trevor Kitson MASSEY UNIVERSITY, NEW ZEALAND While I was a conscript in the service of King George V, on several occasions I moved a destroyer under the circumstances described by your correspondent. At slack tide in Harwich harbour in Essex, and with a slack breeze, I leaned my belly against a stanchion on one ship, stretched with both hands across the narrow gap to a similar stanchion on the ship that was lying alongside, and pulled hard. For perhaps half a minute there seemed to be no result, but slowly the gap between them began to diminish until the two ships came quietly, and without fuss or noise, into contact. And, left alone, they remained in contact. Then, by reversing the process over a similar timescale, and substituting a push for a pull, the two ships returned to their starting positions. The process was remarkably simple. The QE2 is just a trifle larger than a Royal Navy destroyer but I believe that the only difference would be in the timescale required to move the ship. Should your correspondent find an, admittedly unlikely, opportunity to try this experiment with such a large vessel I would advise that he takes care not to hold his breath while pulling. Ken Green TINTAGEL, CORNWALL Take the sting out of Christmas Does Anything Eat Wasps? is published by Profile Books in association with the ‘New Scientist’ and normally sells for pounds 7.99, but readers of ‘The Independent on Sunday’ can buy copies for the special price of just pounds 6.99, including free p&p. To order this perfect Christmas stocking filler, call Independent Books Direct on 08700 798 897 or send a cheque, made payable to Independent Books Direct, to PO Box 60, Helston, TR13 OTP. Place your orders by 12 December to make sure you get your copy in time for the 25th. You can also join the Last Word column’s debates by buying the New Scientist or logging on to www.newscientist.com/ lastword.ns, where you can pose your own question or answer another. Story from REDORBIT NEWS: http://www.redorbit.com/news/display/?id=314550

  • 11:12 pm
  • Leave a comment