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16th Sep 2007
The Best of the BA Festival
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This week we're bringing you the very best bits from the BA Festival of Science in York. We discover a chewing gum that dissolves in the wash but still keeps your breath fresh, get some good news about cancer and find out why jogging may not be good for heart patient recovery if it's near a busy road. Also, Chris risks his health to find out about plague control in 17th Century York, and chocolate may be nicer than it is naughty, as Roger Corder explains how it could be good for your health. Out and about in the festival, Meera explores the psychology of commuter cooperation during the 2005 London bombings, tunes in to non-contact musical instruments and gets immersed in pure colour. Plus, we tackle your questions about good viruses, antioxidants and the Aurora Borealis. In Kitchen science Ben & Dave explore the physics behind a football and find out how to 'Bend it like Beckham.'
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Science News
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Chemists at the University of Bristol have come up with a formulation for chewing gum that could make gum-marked pavements a thing of the past. Terry Cosgrove and his team have developed a new polymer... |
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Sometimes it can seem like the news is full of scare stories about cancer, but this week has seen two pieces of research that could be seen as good news.
First, six years of research have found that... |
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US engineers have developed a system to keep houses cool without turning up the aircon.
Bill Miller and his team from Oak Ridge National Laboratory in Tennessee have come up with a roofing system th... |
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Although exercise is recommended for people who are rehabilitating from a heart attack, new research suggests that you’d probably want to try and steer clear of busy roads while you’re doing it.  ... |
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Scientists in America may have found out why loneliness is linked to health problems.
Writing in the journal Genome Biology, Steve Cole and his colleagues collected blood samples from 14 volunteers w... |
Question of the Week
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How does a cuckoo know it's a cuckoo? Most birds learn from their parents, so does foster parenting leave the cuckoo confused?
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| Interviews
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Sabine Clarke, Oxford University & James Sumner, Manchester University
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Roger Corder, The Royal London Medical School & Peter Rogers, University of Bristol
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John Drury, University of Sussex, & David Steven, Hypnotic Audio
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Kitchen Science
Make an old kitchen,or toilet, roll tube fly and find out what it has to do with David Beckham's free kicks.
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Questions

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In public toilets, there are often automatic hot air hand driers, which come on when you put your hand under them and go off again when you move away. How does the hand drier know when to switch on/off?
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This type of hand drier contains a proximity sensor. If you look underneath the drier, near where the air outlet is, you can see a small glass section, almost like a mini window pane. If you were able to open this up and look inside, you would see an emitter which usually sends out an infra red pulse. Next to the emitter is an infra red receiver. The infra red source is too weak to bounce back from the floor to the receiver, but when you put your hand in the way the infra red beam bounces off your hands back into the receiver and it turns the hot air on. Others are designed with just a receiver to pick up the infra red radiation emitted by your hands.
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If bacteria are constantly evolving and developing resistance to things like antibiotics, why don't they become resistant to soap, ethanol or bleach?
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This is because antibiotics work in a very different way to bleach. Bleach will kill pretty much everything, but antibiotics work in a much more subtle way. Most antibiotics work by targeting specific proteins, such as ones in the cell wall, or those that help make other proteins. A population of bacteria will have variation in genes between one bug and the next and so some will survive. The bacteria that do survive are the ones with variations in their genes which let them cope against the drugs, and so these go on to divide and replace the ones killed by the antibiotics. Bleach is so utterly destructive that virtually nothing survives, so no 'resistance' genes get spread throughout the population.
Most of the drugs we have are derived from a natural source, so bacteria have been locked in this 'arms race' for a very long time. Long before we started using these chemicals to fight off infection.
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Viruses - are they any good? Are any of them actually good for us or symbiotic? For example, cowpox provides immunity to smallpox.
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This may be true, despite that fact that most people think of a virus as being something that makes them feel awful! A recent piece of research in Nature by Skip Virgin, suggested that being infected by one of the family of viruses known as Herpes viruses, such as herpes simplex, which causes cold sores, Epstein-Barr virus, which causes glandular fever. When they infected mice with the rodent equivalent of those infections, the mice developed a much better immune system than mice which had ever been infected. To prove this, they exposed the mice to the bacteria which causes plague and also listeria, and they found these mice to be 100% protected against these bacteria compared with animals which had never been infected with a Herpes virus. When they studies these mice they found molecules called interferon gamma at a much higher level, and this molecule is known to stimulate the immune system. They think that because we've been living with herpes viruses for millions of years, the body has come to rely on infection to provide additional gene function which our body no longer has. This stimulated the immune system and we get some benefit. It's almost a symbiosis, we give the virus a home and it gives us a better immune system.
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I'm a long haul pilot for British Airways, and I've seen the Aurora Borealis quite a lot of times. Every time I've seen them they're Always green in colour, though it can vary. What causes it, and why do you see it on some nights but not others?
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The Aurora Borealis occurs because the Earth has a magnetic field. The Sun is pumping out a million mile per hour maelstrom of charged particles and ions called the cosmic wind, and when this hits our magnetic field the two interact. This is because charged particles are deflected by a magnetic field. When this happens energy is released and this stimulates molecules in the atmosphere to get excited. The dominant molecules in our atmosphere are oxygen and nitrogen, and when excited, oxygen emits light which is mainly green. Sometimes, particles in the solar wind have much higher energy than average, and these can make the oxygen more excited, and you get other colours. In terms of why you only see it on certain nights, it depends to some extent on how much solar activity there is, on atmospheric conditions and whether or not it's cloudy! It only appears at the poles because the magnetic field lines are most concentrated near the north and south pole.
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Do antioxidants in food and supplements really survive stomach acids? Is there any way to ensure that they get into the blood stream?
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Yes they do. If we take, for example, vitamin C, which is actually ascorbic acid, which in theory shouldn't be broken down in an acid environment. We do rely on absorbing vitamins to remain healthy, so the body must have evolved mechanisms to absorb these without them being broken down.
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What is fire, and why is it hot?
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Fire is the burning products of vapours of a fuel. Whenever something burns it is first made into a vapour and mixed with oxygen, so when you have a fuel, such as paraffin or diesel, it works much better if it goes up a wick. This is because the heat can make vapour come from the wick to mix with oxygen in the air to cause a chemical reaction between the hydrocarbons in the fuel and the oxygen. When this happens, you get complete combustion. The flame that you see if just the hot gasses and soot particles, which are so hot that they glow. Gas burns blue because it burns clean, and so there are very few soot particles in the flame to glow yellow.
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