Archive for August, 2010

STFC Grants Consultation

Posted in Science Politics with tags , , , , on August 31, 2010 by telescoper

I thought I’d put my community service badge on today and draw the attention of any astronomers or particle physicists reading this blog that the Science and Technology Facilities Council (STFC) is consulting on proposed changes to the ways it funds research grants. I can hardly over-emphasize the importance of this issue, especially for those of us working in University departments who rely on grant funding in order to carry out our research.

There is a consultation form on which you can post comments on the alternatives outlined in the accompanying document.

Regrettably, only three options are offered. In brief, they are

  1. All grants to be 3-year “standard” grants (i.e. no more “rolling” grants at all)
  2. Some (a small number?) of 6-year “core” grants introduced, mainly to cover the cost of technical support staff.
  3. The status quo (i.e. mixture of 3-year “standard” and 5-year “rolling” grants).

I’m not going to comment on these here, as my intention is just to draw your attention to the fact that this consultation is open and that the deadline is very soon: Monday 6th September 2010, at 4pm. I would have thought it’s probably a good idea for groups to submit collective responses where possible, but I’m sure all feedback would be welcomed.

We don’t know how much of a grant programme will remain after the forthcoming Comprehensive Spending Review, but it’s even more important to make the system as efficient and fair as possible when we know money is going to be tight.


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Dragons and Unicorns

Posted in Education, The Universe and Stuff with tags , , , , , , , on August 30, 2010 by telescoper

When I was an undergraduate I was often told by lecturers that I should find quantum mechanics very difficult, because it is unlike the classical physics I had learned about up to that point. The difference – or so I was informed – was that classical systems were predictable, but quantum systems were not. For that reason the microscopic world could only be described in terms of probabilities. I was a bit confused by this, because I already knew that many classical systems were predictable in principle, but not really in practice. I blogged about this some time ago, in fact. It was only when I had studied theory for a long time – almost three years – that I realised what was the correct way to be confused about it. In short, quantum probability is a very strange kind of probability that displays many peculiarities and subtleties  that one doesn’t see in the kind of systems we normally think of as “random”, such as coin-tossing or roulette wheels.

To illustrate how curious the quantum universe is we have to look no further than the very basic level of quantum theory, as formulated by the founder of wave mechanics, Erwin Schrödinger. Schrödinger was born in 1887 into an affluent Austrian family made rich by a successful oilcloth business run by his father. He was educated at home by a private tutor before going to the University of Vienna where he obtained his doctorate in 1910. During the First World War he served in the artillery, but was posted to an isolated fort where he found lots of time to read about physics. After the end of hostilities he travelled around Europe and started a series of inspired papers on the subject now known as wave mechanics; his first work on this topic appeared in 1926. He succeeded Planck as Professor of Theoretical Physics in Berlin, but left for Oxford when Hitler took control of Germany in 1933. He left Oxford in 1936 to return to Austria but fled when the Nazis seized the country and he ended up in Dublin, at the Institute for Advanced Studies which was created especially for him by the Irish Taoiseach, Eamon de Valera. He remained there happily for 17 years before returning to his native land at the University of Vienna. Sadly, he became ill shortly after arriving there and died in 1961.

Schrödinger was a friendly and informal man who got on extremely well with colleagues and students alike. He was also a bit scruffy even to the extent that he sometimes had trouble getting into major scientific conferences, such as the Solvay conferences which are exclusively arranged for winners of the Nobel Prize. Physicists have never been noted for their sartorial elegance, but Schrödinger must have been an extreme case.

The theory of wave mechanics arose from work published in 1924 by de Broglie who had suggested that every particle has a wave somehow associated with it, and the overall behaviour of a system resulted from some combination of its particle-like and wave-like properties. What Schrödinger did was to write down an equation, involving a Hamiltonian describing particle motion of the form I have discussed before, but written in such a way as to resemble the equation used to describe wave phenomena throughout physics. The resulting mathematical form for a single particle is

i\hbar\frac{\partial \Psi}{\partial t} = \hat{H}\Psi = -\frac{\hbar^2}{2m}\nabla^2 \Psi + V\Psi,

in which the term \Psi  is called the wave-function of the particle. As usual, the Hamiltonian H consists of two parts: one describes the kinetic energy (the first term on the right hand side) and the second its potential energy represented by V. This equation – the Schrödinger equation – is one of the most important in all physics.

At the time Schrödinger was developing his theory of wave mechanics it had a rival, called matrix mechanics, developed by Werner Heisenberg and others. Paul Dirac later proved that wave mechanics and matrix mechanics were mathematically equivalent; these days physicists generally use whichever of these two approaches is most convenient for particular problems.

Schrödinger’s equation is important historically because it brought together lots of bits and pieces of ideas connected with quantum theory into a single coherent descriptive framework. For example, in 1911 Niels Bohr had begun looking at a simple theory for the hydrogen atom which involved a nucleus consisting of a positively charged proton with a negatively charged electron moving around it in a circular orbit. According to standard electromagnetic theory this picture has a flaw in it: the electron is accelerating and consequently should radiate energy. The orbit of the electron should therefore decay rather quickly.

Bohr hypothesized that special states of this system were actually stable; these states were ones in which the orbital angular momentum of the electron was an integer multiple of Planck’s constant. This simple idea endows the hydrogen atom with a discrete set of energy levels which, as Bohr showed in 1913, were consistent with the appearance of sharp lines in the spectrum of light emitted by hydrogen gas when it is excited by, for example, an electrical discharge. The calculated positions of these lines were in good agreement with measurements made by Rydberg so the Bohr theory was in good shape. But where did the quantised angular momentum come from?

The Schrödinger equation describes some form of wave; its solutions \Psi(\vec{x},t) are generally oscillating functions of position and time. If we want it to describe a stable state then we need to have something which does not vary with time, so we proceed by setting the left-hand-side of the equation to zero. The hydrogen atom is a bit like a solar system with only one planet going around a star so we have circular symmetry which simplifies things a lot. The solutions we get are waves, and the mathematical task is to find waves that fit along a circular orbit just like standing waves on a circular string. Immediately we see why the solution must be quantized. To exist on a circle the wave can’t just have any wavelength; it has to fit into the circumference of the circle in such a way that it winds up at the same value after a round trip. In Schrödinger’s theory the quantisation of orbits is not just an ad hoc assumption, it emerges naturally from the wave-like nature of the solutions to his equation.

The Schrödinger equation can be applied successfully to systems which are much more complicated than the hydrogen atom, such as complex atoms with many electrons orbiting the nucleus and interacting with each other. In this context, this description is the basis of most work in theoretical chemistry. But it also poses very deep conceptual challenges, chiefly about how the notion of a “particle” relates to the “wave” that somehow accompanies it.

To illustrate the riddle, consider a very simple experiment where particles of some type (say electrons, but it doesn’t really matter; similar experiments can be done with photons or other particles) emerge from the source on the left, pass through the slits in the middle and are detected in the screen at the right.

In a purely “particle” description we would think of the electrons as little billiard balls being fired from the source. Each one then travels along a well-defined path, somehow interacts with the screen and ends up in some position on the detector. On the other hand, in a “wave” description we would imagine a wave front emerging from the source, being diffracted by the screen and ending up as some kind of interference pattern at the detector. This is what we see with light, for example, in the phenomenon known as Young’s fringes.

In quantum theory we have to think of the system as being in some sense both a wave and a particle. This is forced on us by the fact that we actually observe a pattern of “fringes” at the detector, indicating wave-like interference, but we also can detect the arrival of individual electrons as little dots. Somehow the propensity of electrons to arrive in positions on the screen is controlled by an element of waviness, but they manage to retain some aspect of their particleness. Moreover, one can turn the source intensity down to a level where there is only every one electron in the experiment at any time. One sees the dots arrive one by one on the detector, but adding them up over a long time still yields a pattern of fringes.

Curiouser and curiouser, said Alice.

Eventually the community of physicists settled on a party line that most still stick to: that the wave-function controls the probability of finding an electron at some position when a measurement is made. In fact the mathematical description of wave phenomena favoured by physicists involves complex numbers, so at each point in space at time \Psi is a complex number of the form \Psi= a+ib, where i =\sqrt{-1}; the corresponding probability is given by |\Psi^2|=a^2+b^2. This protocol, however, forbids one to say anything about the state of the particle before it measured. It is delocalized, not being definitely located anywhere, but only possessing a probability to be any particular place within the apparatus. One can’t even say which of the two slits it passes through. Somehow, it manages to pass through both slits. Or at least some of its wave-function does.

I’m not going to into the various philosophical arguments about the interpretation of quantum probabilities here, but I will pass on an analogy that helped me come to grips with the idea that an electron can behave in some respects like a wave and in others like a particle. At first thought, this seems a troubling paradox but it only appears so if you insist that our theoretical ideas are literal representations of what happens in reality. I think it’s much more sensible to treat the mathematics as a kind of map or sketch that is useful for us to do find our way around nature rather than confusing it with nature itself. Neither particles nor waves really exist in the quantum world – they’re just abstractions we use to try to describe as much as we can of what is going on. The fact that it doesn’t work perfectly shouldn’t surprise us, as there are are undoubtedly more things in Heaven and Earth than are dreamt of in our philosophy.

Imagine a mediaeval traveller, the first from your town to go to Africa. On his journeys he sees a rhinoceros, a bizarre creature that is unlike anything he’s ever seen before. Later on, when he gets back, he tries to describe the animal to those at home who haven’t seen it.  He thinks very hard. Well, he says, it’s got a long horn on its head, like a unicorn, and it’s got thick leathery skin, like a dragon. Neither dragons nor unicorns exist in nature, but they’re abstractions that are quite useful in conveying something about what a rhinoceros is like.

It’s the same with electrons. Except they don’t have horns and leathery skin. Obviously.


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The Character of a Happy Life

Posted in Poetry with tags , on August 29, 2010 by telescoper

How happy is he born or taught
That serveth not another’s will,
Whose armour is his honest thought,
And simple truth his highest skill;

Whose passions not his masters are;
Whose soul is still prepared for death,
Untied unto the world with care
Of princes’ grace or vulgar breath;

Who envies none whom chance doth raise,
Or vice; who never understood
The deepest wounds are given by praise,
By rule of state but not of good;

Who hath his life from rumours freed,
Whose conscience is his strong retreat,
Whose state can neither flatterers feed
Nor ruins make accusers great;

Who God doth late and early pray
More of his grace than goods to send,
And entertains the harmless day
With a well-chosen book or friend.

This man is free from servile bands
Of hope to rise or fear to fall,
Lord of himself, though not of lands,
And having nothing, yet hath all.

by Sir Henry Wotton (1568-1639).


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Political Correlation

Posted in Bad Statistics, Politics with tags , , , , on August 28, 2010 by telescoper

I was just thinking that it’s been a while since I posted anything in my bad statistics category when a particularly egregious example jumped up out of this week’s Times Higher and slapped me in the face. This one goes wrong before it even gets to the statistical analysis, so I’ll only give it short shrift here, but it serves to remind us all how feeble is many academic’s grasp of the scientific method, and particularly the role of statistics within it. The perpetrator in this case is Paul Whiteley, who is Professor of Politics at the University of Essex. I’m tempted to suggest he should go and stand in the corner wearing a dunce’s cap.

Professor Whiteley argues that he has found evidence that refutes the case that increased provision of science, technology, engineering and maths (STEM) graduates are -in the words of Lord Mandelson – “crucial to in securing future prosperity”. His evidence is based on data relating to 30 OECD countries: on the one hand, their average economic growth for the period 2000-8 and, on the other, the percentage of graduates in STEM subjects for each country over the same period. He finds no statistically significant correlation between these variates. The data are plotted here:

This lack of correlation is asserted to be evidence that STEM graduates are not necessary for economic growth, but in an additional comment (for which no supporting numbers are given), it is stated that growth correlates with the total number of graduates in all subjects in each country. Hence the conclusion that higher education is good, whether or not it’s in STEM areas.

So what’s wrong with this analysis? A number of things, in fact, but I’ll start with what seems to me the most important conceptual one. In order to test a hypothesis, you have to look for a measurable effect that would be expected if the hypothesis were true, measure the effect, and then decide whether the effect is there or not. If it isn’t, you have falsified the hypothesis.

Now, would anyone really expect the % of students graduating in STEM subjects  to correlate with the growth rate in the economy over the same period? Does anyone really think that newly qualified STEM graduates have an immediate impact on economic growth? I’m sure even the most dedicated pro-science lobbyist would answer “no” to that question. Even the quote from Lord Mandelson included the crucial word “future”! Investment in these areas is expected to have a long-term benefit that would probably only show after many years. I would have been amazed had there been a correlation between measures relating to such a short period, so  absence of one says nothing whatsoever about the economic benefits of education in STEM areas.

And another thing. Why is the “percentage of graduates” chosen as a variate for this study? Surely a large % of STEM graduates is irrelevant if the total number is very small? I would have thought the fraction of the population with a STEM degree might be a better choice. Better still, since it is claimed that the overall number of graduates correlates with economic growth, why not show how this correlation with the total number of graduates breaks down by subject area?

I’m a bit suspicious about the reliability of the data too. Which country is it that produces less than 3% of its graduates in science subjects (the point at the bottom left of the plot). Surely different countries also have different types of economy wherein the role of science and technology varies considerably. It’s tempting, in fact, to see two parallel lines in the above graph – I’m not the only one to have noticed this – which may either be an artefact of small numbers chosen or might indicate that some other parameter is playing a role.

This poorly framed hypothesis test, dubious choice of variables, and highly questionable conclusions strongly suggest that Professor Whiteley had made his mind up what result he wanted and simply dressed it up in a bit of flimsy statistics. Unfortunately, such pseudoscientific flummery is all that’s needed to convince a great many out there in the big wide world, especially journalists. It’s a pity that this shoddy piece of statistical gibberish was given such prominence in the Times Higher, supported by a predictably vacuous editorial, especially when the same issue features an article about the declining standards of science journalism. Perhaps we need more STEM graduates to teach the others how to do statistical tests properly.

However, before everyone accuses me of being blind to the benefits of anything other than STEM subjects, I’ll just make it clear that, while I do think that science is very important for a large number of reasons, I do accept that higher education generally is a good thing in itself , regardless of whether it’s in physics or mediaeval latin, though I’m not sure about certain other subjects.  Universities should not be judged solely by the effect they may or may not have on short-term economic growth.

Which brings me to a final point about the difference between correlation and causation. People with more disposal income probably spend more money on, e.g., books than people with less money. Buying books doesn’t make you rich, at least not in the short-term, but it’s a good thing to do for its own sake. We shouldn’t think of higher education exclusively on the cost side of the economic equation, as politicians and bureaucrats seem increasingly to be doing,  it’s also one of the benefits.


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No Science Please, We’re British

Posted in Education, Politics, Science Politics with tags , , , , , , , , , on August 27, 2010 by telescoper

The time is getting closer when the Condem government’s hatchet men announce the detailed plans for spending cuts over the next few years. Those of us scientists working in British universities face an anxious few weeks waiting to see how hard the axe is going to fall. Funds for both teaching and research seem likely to be slashed and there’s fear of widespread laboratory closures across the sector, particularly in “pure” science that doesn’t satisfy the current desire for a rapid return on investment.

The mood is pretty accurately summarised by an article in the Guardian, in which John Womersley (who is the Director of Science Programmes at the Science and Technology Facilities Council) pointed out the very real possibility that the UK might be forced to mothball expensive national facilities such the recently built Diamond Light Source and/or withdraw from international collaborations such as CERN (which would also entail pulling out of the Large Hadron Collider). Astronomers also fear that cuts to STFC might force us to withdraw from the European Southern Observatory, which would basically destroy our international competitiveness in a field which for so long we have been world-leading. Withdrawal from CERN would similarly ensure the end of particle physics in Britain.

As well as the loss of facilities and involvement in ongoing international research programmes, big cuts in science funding – especially at STFC – will also lead to a “lost generation” of young scientists having little or no opportunity to carry out their research here in Britain. In fact the process of throwing away the UK’s future as a scientific nation has already begun and is likely to accelerate even without further cuts this year.

The STFC budgets for training young scientists at both postgraduate and postdoctoral levels were slashed even before the General Election because STFC was formed in 2007 with insufficient funds to meet its commitments. The total funding for research grants in astronomy – which is how many postdoctoral researchers are trained has been squeezed by an unsustainable level of 40% already. Many young scientists, whose contracts have been terminated with virtually no notice, have not unreasonably decided that the UK can offer them nothing but a kick in the teeth and gone abroad, taking their expertise (which was developed thanks to funding provided by the UK taxpayer) to one of our competitors in the global economy.

Some say the previous funding crisis was due to downright incompetence on behalf of the STFC Executive, some say it was part of a deliberate policy at the RCUK level to steer funding away from pure science towards technology-related areas. Either way the result is clear. Opportunities for young British scientists to do scientific research have been severely curtailed. Another round of cuts to STFC of the 25% being talked about by the new government will certainly lead to wholesale closures of labs and observatories, the withdrawal from international commitments such as CERN and ESO, and the loss of irreplaceable expertise to other countries.

On top of this, it seems not only STFC but also other research councils (such as EPSRC) are talking about clawing back funds they have already granted, by reneging on contracts they have already signed with Universities to fund research by scientists carried out there. If this does happen, there will be a catastrophic breakdown of trust between University-based scientists and the government government that will probably never be healed.

This government risks destroying the foundations of scientific excellence that have taken over 300 years to build, and all for what level of saving? The annual subscription the UK pays to CERN is about £70 million, a couple of pounds per British taxpayer per year, and a figure that most bankers would regard as small change. It would be madness to throw away so much long-term benefit to save so little in terms of short-term cost.

In the Guardian article, John Womersley is quoted as saying

Our competitor nations such as Germany and the US are investing in science and engineering right now because they recognise that they stimulate economic growth and can help to rebalance the economy. It is pretty obvious that if the UK does the exact opposite, those companies will look elsewhere. That would deepen the deficit – in a recession you need to invest in science and engineering to reap the benefits, not cut back.

Of course we don’t know how the Comprehensive Spending Review will turn out and there may be still time to influence the deliberations going on in Whitehall. I hope the government can be persuaded to see sense.

I’m trying very hard to be optimistic but, given what happened to STFC in 2007, I have to say I’m very worried indeed for the future of British science especially those areas covered by STFC’s remit. The reason for this is that STFC’s expenditure is dominated by the large facilities needed to do Big Science, many of which are international collaborations.

In order to be active in particle physics, for example, we have to be in CERN and that is both expensive and out of STFC’s control. The cost of paying the scientists to do the science is a relatively small add-on to that fixed cost, and that’s the only bit that can be cut easily. If we cut the science spend there’s no point in being in CERN, but we can’t do the science without being in CERN. The decision to be made therefore rapidly resolves itself into whether we do particle physics or not, a choice which once made would be irreversible (and catastrophic). It’s the same logic for ESO and ground-based astronomy. There’s a real possibility in a few years time that the UK will have killed off at least one of these immensely important areas of science (and possibly others too).

A decade ago such decisions would have been unthinkable, but now apparently they’re most definitely on the cards. I don’t know where it all went wrong, but given the (relatively) meagre sums involved and the fact that it started before the Credit Crunch anyway, it’s difficult to escape the conclusion that it’s a deliberate stitch-up by senior mandarins. All I can say is that the future looks so grim I’m glad I’m no longer young.


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The Girls Go Crazy

Posted in Jazz with tags , , on August 26, 2010 by telescoper

It’s thoroughly wet and miserably cold – especially considering it’s meant to be summer – so I’ve been looking around for something to brighten up the evening and chanced upon this piece of traditional jazz which did the trick for me. This is the kind of New Orleans style jazz band my Dad used to play the drums for, and the tune is one I actually learned to play on the clarinet so I could sit in with them once or twice so it brought back quite a few nice memories hearing it just now. It’s based on an interesting 16-bar blues theme (in contrast to the usual 12-bar variety) that was ubiquitous in early jazz, appearing in a number of different tunes. In this particular manifestation it’s called The Girls Go Crazy (About the Way I Walk).

It’s neither a famous band nor a famous recording, but I bet everyone who was there that sunny day last year in San Francisco thoroughly enjoyed the occasion, especially the band!

150 Years of Fish and Chips

Posted in Uncategorized with tags , , , , , , on August 26, 2010 by telescoper

This is definitely off the beaten track as far as my blog posts go, but I think it’s Quite Interesting so I thought I’d share it with you. I was wondering the other day where and when the traditional “British” dish of fish and chips originated. The answer is fascinating, and a little bit controversial too.

The practice of eating fried fish in batter started to appear in England during the fifteenth century; it was derived from the  Pescado Frito cooked by Portuguese Sephardic Jews – Marranos – who had moved to Britain to escape persecution in their homeland. By the Victorian era “Fish Fried in the Jewish Fashion” was extremely popular in the working class districts of London, particularly in the East End. Dickens refers to a “fried fish warehouse” in Oliver Twist, which was first published in 1837. It seems to have become available in large quantities with the rapid development of trawler fishing in the mid 19th century.

Incidentally, there is a prominent relic  of the Spanish and Portuguese Jews who settled in the East End right next to Queen Mary, University of London in Mile End (see left). The burial ground has, I think, recently been moved but it neverthless provides a timely reminder that immigration is by no means a new phenomenon as far as the East End is concerned.

The traditional way of frying the fish involved oil and I don’t know precisely when the practice of using lard – which is what is used in many modern shops – came on the scene, but it clearly would not have met with Jewish approval and must have been a more recent development.

The origin of chips is more controversial. The first occurence of this usage of the word chip in the Oxford English Dictionary appears in Dickens’ novel A Tale of Two Cities, dated 1859, in the phrase

Husky chips of potatoes, fried with some reluctant drops of oil

Some say the practice of frying potatoes like this originated in Belgium or France, and that chips are a British version of pommes frites or french fries. This style of cooking potatoes could have been brought to London by the Huguenots (French Protestants who settled in the East End of London after being forced out of their homeland). However, there is some controversy about how and why chips became so popular throughout Britain. Some claim the practice of eating fried potatoes was already established in the North of England before 1859. It also seems that fried chipped potatoes were served in working class eating establishments throughout Victorian London. Many working people – especially single men living in lodging houses – lacked the facilities or the ability to cook anything substantial at home, so preferred to buy their food ready made. At an Irish Ordinary you could get a filling meal of beer, meat and fried potatoes for about tuppence (in old money). Such establishments proliferated all over London during the 19th Century as the number of navvies and other itinerant Irish labourers  grew in response to the demand for manual workers across the country.

I think it was most likely the presence of a nearby Irish Ordinary that led a Jewish londoner called Joseph Malin to hit upon the idea of combining fried fish with chipped potatoes. At any rate it’s reasonably well established that the very first commercial Fish-and-Chip Shop was opened by him in 1860 in Cleveland Street and business was so good that it was followed by many others across the East End of London and beyond.

There’s something rather inspiring about rediscovering that Britain is nation whose traditions and institutions have always been so reliant on foreign immigrants. Even Fish and Chips turns out to be from somewhere else. Makes you proud to be British.


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