|
|
Science News
|
German manufacturing giant BASF have developed a new way to protect sea walls from the incessant crashing of the sea - by giving them a holey coating which behaves like... |
|
If you are going to predict the weather the first thing you need to know is what the weather is like now, the second thing you have to know is whether your prediction was right so you can improve your... |
|
In a step that will see computers become even closer to being an extension of the body, Microsoft Research are now looking into ways to implement foot pedals to help yo... |
Kitchen Science

Derek and Sheena visit Downham market high school to find out what effect molecular vibrations have on ink and water.
|
Questions

|
Do TV and radio signals travel vertically, and if they do, do they disappear or travel off into space forever? If so, does that mean that a signal from the 1950s is still in space somewhere?
|
|
|
Yes the signals we create are creating a sort of bubble around the earth which is expanding at the speed of light. That means that the bubble is roughly 100 light years across now and spreading away from the earth. But when you think that the Milky Way is easily about 100 000 light years across, it's going to take a long while for many of the stars just in our own galaxy to hear us. When you consider that there are 10 000 000 000 000 000 000 000 stars out there, it is going to take a long while before the messages get to anyone else. So it is not surprising we haven't heard anyone replying yet.
|

|
I was listening to my radio one night and I noticed that when I turned on my desk light there was a little blip of noise on the radio. I repeated this and I noticed that when I was on the border of completing the circuit, such that when the bulb was flickering, I got severe interference on my radio. My radio was running on batteries. Why does this happen?
|
|
|
When your light switch is just on the border of making a circuit, you are creating a switch which is almost closed. At some point the switch will create a spark. When you create a spark you will create a little surge of current in the wire. The spark will then finish and break the circuit again. You will keep getting sparks, each creating it's own surge of current. Your light bulb is flickering because you have a changing current, and a changing current will produce a changing magnetic field. A changing magnetic field produces a changing electric current. So when we create a radio wave, what you've got is a transmitter which is applying a changing electric field to a piece of metal (the aerial). The changing current going up and down that piece of metal then induces a changing magnetic field around the metal and the changing magnetic field then creates a change in electrical current in the fabric of space around it. That electrical current in space time produce a wiggle of magnetic field, and so you get this wave that propagates as an alternating magnetic field and electrical field. This propagates through space at roughly the speed of light. That's a radio wave. So why did your interfere with your radio? Well when you're just on the verge of completing a circuit with your light, it's creating enormous amounts of changing current in the wire. This creates lots of funny frequencies of radio waves at a fairly low power. These then come out around the wire, spread out into the room and are picked up by the aerial of your radio. They interfere destructively. In other words they cancel out the radio waves of the station you were listening to. That's why you get the interference.
|

|
As far as I know, mammals do not use the colours blue or green, but most other animals and plants do. Is there a reason for this?
|
|
|
Animals are the colour they are to blend in with their environment. The key thing that drives survival is not being preyed upon or eaten. If you're not eaten then you get to have babies and you pass your genes on to the next generation. If you're a polar bear and your genes make you white, then you're less likely to be caught and eaten. As a result, you're more likely to have babies and those babies will have babies. So animals will change their colour so that they're the same as the surroundings and blend in. That either makes their hunting easier or they don't get eaten by other things. It might be that the colours you're referring to have not been adopted because they're not very good colours in nature. A snake is a greeny-brown colour because it wants to blend into the background. Other animals use the converse. They don't want to blend in because they want to mark out that they're toxic. That's why they use colour. The other reason they use colour, especially in things like fish, is for part of the mating game. It can be used for recognition and communication. Actually, I think baboons have big blue noses and I think there is a mammal that is green, although it's for a slightly different reason. It's called a three-toed sloth. The reason it's green is because moss grows on its fur as it moves so slowly.
|

|
Have we got a time bomb in the population with mad cow disease?
|
|
|
I don't think so. The number of cases of this new form of CJD rose to a peak of 28 cases in the year 2000. Last year there were five. It looks very much that far from being a time bomb, numbers are dropping and the disease is under control. That's what I would say. When the first cases appeared in the end of 1995 and the beginning of 1996, nobody knew what the incubation period was. We knew that the maximum exposure of people to contaminated beef was around 1990 and so some people said that if there's a 20 year incubation period, then these first cases in 1996 might expand to hundreds of thousands of cases in 20 years time. Nobody could be sure that that wasn't right. It turned out that the incubation period is about ten years, BSE transmits very inefficiently to people and the maximum of 28 people in 2000 was the maximum. Now it's going steadily down.
|
| Interviews
|
Chelsea Wald and Bob Hirshon From Aaas
|
|
Professor Tony Minson, University of Cambridge
|
|
Dr Joanne Webster, Imperial College London
|
|
Professor Margaret Stanley, University of Cambridge
|
| BSE, Cervical Cancer and Toxoplasmosis - More about this podcast BSE - Bovine Spongiform Encephalopathy, commonly known as "mad cow disease" was first recognised in the UK in 1986 and became an epidemic; peaking in 1992 as 37,000 cases were reported that year. To date over 183,000 cases have been confirmed, altough the number of new cases is now at its lowest since records began. And at the beginning of May (2006) the EU lifted the worldwide ban on British beef exports, ten years after it was introduced to prevent the spread of BSE. (source: Defra)
So why is it called "mad cow disease"? - BSE occurs in adult animals of both sexes, usually in animals aged over 5 years. It is a neurological disease in which affected animals show signs that include: changes in mental state, abnormalities of posture, movement and sensation .The clinical disease usually lasts for several weeks and is invariably progressive and fatal.
BSE has been linked to CJD - Creutzfeld - Jakob disease; this is a disease which causes paralysis and death in humans. Over 140 people have been diagnosed since it first appeared in the UK and most of them have died. How does it spread between cows? What is the link to humans? Why did it take so long to eradicate the disease? Is British beef now safe? To answer these questions and any others you may have, two eminent Cambridge professors in pathology, both of whom have acted in an advisory capacity in relation to this disease, will appear on the Naked Scientists this week. Here's a bit of background to their work...
Professor Minson specialises in herpesviruses which are amongst the largest and most complex viruses. Different members of the herpes virus are responsible for different human diseases ranging from chicken pox, glandular fever, cold sores and genital herpes, as well as economically important infections in domestic animals - such as BSE. All herpesviruses are composed of at least 30 different proteins of which ten or more are inside the membrane which surrounds the virus particle. Interactions between these membrane proteins and the host cell are the first step in the infection process; this causes the fusion of the virus and host membranes which releases the virus core into the cell. All enveloped viruses can induce membrane fusion but the herpesviruses are special because membrane fusion and the entry of the virus into the host cell is achieved by the action of four different viral membrane proteins. Minson's research attempts to define how the membrane proteins are assembled into the virus particle and how they function together to create membrane fusion.
Professor Margaret Stanley specialises in HPV - human papillomavirus. These are a large group of pathogens which infect skin and mucus membranes, which can cause a variety of disorder from warts to cancer. Certain types of HPV particularly HPV 16 and HPV 18 are closely connected with the development of some human cancers, particularly cervical cancer. Margaret has been a key player in the development of the world's first cervical cancer vaccine which is currently showing extremely promising results in trials that are on-going. Cervical cancer is one of the leading causes of death amongst women worldwide, and especially in the 3'rd world where countries lack the infrastructure and funding to implement a screening programme. |
|
|