Chris -   A listener, David in Fincham, has informed us that mainline trains ran at 17 atmospheres, the Flying Scotsman at 15 atmospheres and older models around 10 atmospheres. Also, Mr. Wikipedia tells us that high pressure steam locomotives operated between 23 and even up to 100 atmospheres, that’s 1500 psi, but they did need special design to do that.

We put this question to Professor Stephen Bennington from the Rutherford Appleton Laboratory...

Stephen -  Well it’s like digital technology, so it’s using electrons.  But instead of just having on and off as your two states, you can use the spin of the electron so that spin can be up/down, and so you have much more information in there.  But instead of using silicon, you can't just use silicon for these kinds of things.  You've got to use much more complicated magnetic materials and you've got to make them nano scale.  You know, silicon at the moment is at 45 nanometre, so you've got to make these complex materials also nano scale.  We do a lot of work on this at the Neutron Source which is very good at looking magnetic materials.

We put this question to Professor Stephen Bennington from the Rutherford Appleton Laboratory...

It shouldn’t do because it’s recycling it.  So I mean you're taking water, you split it up into hydrogen and oxygen, and then you recombine them again in your car.  So, the net effect is zero.  Water vapour is different perhaps because if you're using these things to power jets up in the high atmosphere and then you're depositing water vapour up there, and that’s a greenhouse gas.  So we have to think carefully about those problems.  It’s probably not a problem, but it could be.

We posed this question to Professor Stephen Bennington from ISIS at the Rutherford Appleton Laboratory...

Stephen: -   Well I know there’s water up there.  NASA scientists have discovered this recently, but there’s no hydrogen as far as we know.  I've not seen any reports of it.  Hydrogen will only stick on surfaces either below 20 Kelvin or in very thin layers up to perhaps about 50 Kelvin, and most of the moons are higher temperatures than that.  There might be little dark areas whether it’s cold in there, but on the whole, no.

Chris: -   But the fact they found water out there with the mission to slam the probe into the south pole of the moon, means that we can just get the hydrogen we need by extracting the water and electrolysing it presumably.

Stephen: -   Absolutely, yes.

Chris: -   So it shouldn’t be a problem. 

We discussed this with Stephen Bennington, from ISIS at the Rutherford Appleton Laboratory...

Chris: - Is this similar to the work you do Stephen?

Stephen: -   Well we do work on what they call ‘intercalated graphites’ which is graphites which contain metals in between their layers, and the reason for doing that is that the metals charge up the layers of the graphite, and that means that the hydrogen sticks to it more readily.  So this theoretical work by these Greek people was very interesting because it also spaces the layers of the graphite at the perfect distance to stick hydrogen in the middle.  It’s only theoretical.

Chris: -   They give you a massive surface area.

Stephen: -   Big surface area, yes.

Chris -  The answer is, yes, they do.  The gene which enables us to see red light, in other words, encodes the red detecting pigment in the retina is carried on the X-chromosome, and because women have two X-chromosomes that they inherit from their parents – one from the mother and one from the father, they therefore have two genes in their body that are capable of detecting red.

But during development, one of the X-chromosomes is randomly inactivated.  This is called ‘X-chromosome inactivation’ because you don't want two copies of the chromosome active because you only need one because men only have one copy. 

But that process of inactivation is random in the tissues which means that some cells will be using one X-chromosome whilst other cells could be using the other X-chromosome, and therefore, if you extend that to the retina, there’ll be some cells in the retina that are seeing red, using the gene on one X-chromosome, and some cells seeing red using the gene on the other X-chromosome.

And this means theoretically, there could be different genes running in different bits of the retina, and therefore, the perception of red could be slightly different in different positions on the retina in women. 

But because men have only one X-chromosome because our genotype is XY, we therefore don't inactivate an X-chromosome, and therefore use the same gene throughout the retina, and that’s why you also find men who can be colour blind because they can inherit a red receptor that doesn’t work.

Whilst women, because they have two X-chromosomes, even if one of them has a defective copy, the other one is almost certainly still going to work and therefore, in general, you don't find women who have colour blindness.  So the answer is yes.