Seat of learning
Concerning Feedback’s article about blackboards in the Isaac Newton Institute, Cambridge, (May 27): Yes, there is a blackboard in the ladies toilet. There is also an intriguing notice, written in several languages, to the effect “would people wishing to stand on the toilet please lift the seat first”.
Whale of a story
The exploding whale story may be older than Feedback (20 May) suggests. I was told the following version in the mid 1960s.
A circus was travelling by ship from Liverpool to the US. A storm blew up and one of the elephants was swept overboard. Its carcass washed up on Tory Island off the coast of Donegal, where it soon made its presence felt.
After a long debate the authorities decided to entomb the beast where it lay, by pouring concrete over it. This worked, for a while. However, the gases of decomposition formed an explosive mixture, which ignited spontaneously. Pieces of concrete and rotting elephant were scattered the length and breadth of the island. The bones can be found there to this day.
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No surprise
The findings of Dennis Choi et al that neurotrophins harm oxygen-deprived nerve cells may surprise cell biologists (New 杏吧原创, Science, 13 May), but they would not surprise their less sophisticated colleagues in the world of anaesthetics. The brain is not well suited to anaerobic metabolism, unlike muscle, and therefore depends on oxygen.
It has long been recognised that the cornerstone of looking after a brain with a compromised circulation is to reduce its metabolism (for example with barbiturates and modest cooling) and to maintain its blood supply (by manipulating blood pressure, intracerebral pressure and cerebral blood flow) thereby maintaining a favourable oxygen budget; a simple approach of matching supply to demand.
Any measure, such as giving neurotrophins, that boosts metabolism in the face of oxygen deficit is bound to lead to trouble for the cells 鈥� and the patient. The fact that cultured nerve cells died when made to work harder in conditions of oxygen shortage is consistent with this argument.
Antiatoms
Researchers at Fermilab, under the guidance of physicist Rosanna Cester from Torino University, have already synthesised antihydrogen, albeit unwittingly (“The race to create an antiatom”, 13 May).
Cester’s group planned an experiment to study certain meson states produced by intercepting an intense beam of 6 脳 1011 antiprotons with a hydrogen gas jet target. The antiprotons were kept in a tight orbit inside the vacuum vessel at Fermilab’s equivalent of the LEAR storage ring, the Antiproton Accumulator.
By carefully controlling the momenta of the circulating antiprotons, Cester and co-workers studied the formation and subsequent decay of charmonia, the bound states of a charm-anticharm quark.
Most of the time the circulating antiprotons crossed the gas jet target uneventfully. Sometimes an antiproton passed close to a hydrogen nucleus, violently disturbing its electric field and, in the process, creating an electron-positron pair. When the momenta of the emerging antiproton-positron matched closely, then the antiproton snatched the positron and the two, now combined as an electrically neutral antihydrogen atom, flew away, escaping the influence of the steering magnets.
Although this process is very rare, it is estimated that more than a few hundred antihydrogen atoms have been produced at Fermilab during the recent runs of Cester’s experiment. Charles Munger (a physicist with the Stanford Linear Accelerator) and colleagues recognised this serendipitous antihydrogen production and currently are finishing the construction of a suitable detector, in order to confirm the phenomenon. Munger’s group, in addition to establishing the production of antihydrogen, may measure one of its fundamental spectroscopic transitions, the Lamb shift.
Apart from Munger’s antihydrogen detection experiment, an additional baryonic test of CPT symmetry was conducted at Fermilab when the ApEx collaboration directly measured a minimal lifetime for the antiproton itself. Interestingly, it is an antimatter nuclear reaction, proton-antiproton annihilation to certain meson pairs, which promises to shed light on the ill-understood CP symmetry violation; the reason antihydrogen is so rare a substance.
Between friends
Comments regarding American pronunciation in Feedback (11 March), reminded me of my experiences and theorising as an immigrant to Alberta from Lancashire. It did not take me long to discover that a word in common use back there was still in use here, but pronounced a little differently.
Butty had always meant a sandwich to me, and was usually prefixed by a descriptive pronoun: jam butty, meat butty and so on, depending on content. I later discovered that, as used in northwest Ireland, it also meant the work mate with whom one would share ones sandwiches, if he had forgotten his own.
The next step was the realisation that the spread of American mispronunciation had given us what at first appeared to be a new word, but which really had its roots in my own dialect.
I am your long lost Buddy.
Picking up pieces
We frequently read about work being done to piece together fragmentary documents. For example, recent New 杏吧原创 articles, and subsequent correspondence, have been concerned with piecing together fragments of the Dead Sea Scrolls. In this work, not only do the documents suffer from missing information, but also the correct sequence of the existing information is not known. In other situations, only information is missing, such as reconstructing the intentions of a composer where only a sketch of a work has survived, or a small number of orchestral or chorus parts.
It is possible that some techniques which are familiar to physical scientists might be put to good use here. One of the most important is the idea of independent verification. If an experimenter repeats a measurement, and tries to make every adjustment, independent of the first measurement, or even better gets someone else to do it, then agreement between the two measurements strongly reinforces our confidence in their correctness.
On the other hand, when a fragmentary musical composition is discovered, often the person who discovers it will delay disclosing it, and eventually publish it with a suggested completion. It is then impossible for anyone else to publish an independent completion (especially the original discoverer), since they would be unable to ignore the first version published.
It would therefore be very interesting to consider whether the disclosure of new material could be managed so as to allow independent confirmation of any reconstructions. For example, a collection of scroll fragments could be photographed (with the lighting adjusted to bring out the text and the structure of the material as clearly as possible) and copies made available to a number of workers. They would agree (as a condition of being given access to this material) not to publish anything prematurely, but to work independently, and submit any reconstructions to a conference or workshop to be held at a fixed date in the future.
Under these conditions, if a number of people independently came up with identical reconstructions, then there would be good reason to claim that these were the only possible readings of the material. It would be even more conclusive if some of the workers started off with a different philosophy, so that they actively wanted the results to be different.
Obviously, the probability of agreement depends on the type and amount of missing material. If the documents were 90 per cent complete, then identical reconstructions would be much more likely than if they were only 50 per cent complete, while some musical works might be reconstructible when less than 25 per cent complete. Below a certain figure, it would be doubtful if any two people would come up with identical results. This would not make the exercise worthless since, rather than being presented with a fait accompli (as would happen when a single worker publishes a reconstruction), we would have a practical demonstration that a reliable reconstruction was not possible with the available material.
These ideas might also be applicable to three-dimensional problems. Museums often exhibit ancient pieces of pottery, in which only one or two small fragments are original. We usually have to take it on trust that every expert, on being given these same original fragments, would come up with the same result. Of course, photographing the pieces would not be sufficient, but independent investigators might be supplied with plaster casts, or enlarged replicas constructed using laser-profiling and computer-controlled machining.
I don’t know whether this type of independent corroboration has ever been organised for the analysis of fragmentary material 鈥� articles in New 杏吧原创 haven’t mentioned it. If it has, it would be interesting to hear about it, and learn how often independent workers do come up with the same reconstructions.
Petrol payment
The assessment of the Government’s White Paper on the future of nuclear power (This Week, 20 May) and the article by Lisa Woolhouse and Ian Fells (Forum, 27 May) strongly imply that carbon emissions will increase as a consequence of not building any new nuclear power stations. It was part of Nuclear Electric’s case in the Nuclear Review that new nuclear plants were “essential” to achieve likely future carbon emission reduction targets.
We challenged this claim by commissioning Cambridge Econometrics to project how future British energy requirements could be met without more nuclear power and without increasing carbon emissions. Using the most advanced energy-environment-economy computer model in Britain, it showed that additional support for energy efficiency and renewables paid for by increased petrol duty at 7.5 per cent annually in place of the current 5 per cent escalator, could control energy demand; it could also cut British carbon emissions by the year 2020 to 18 per cent less than levels in 1990, and it would be neutral in its overall economic impact.
Since commissioning this work both Cambridge Econometrics and the Department of Trade and Industry (Energy Paper 65) have revised their carbon emission projections, but our case still holds. Of course, the DTI’s Nuclear Review Team found Nuclear Electric’s case wanting.
Carbon market
Jonathan Loh of World Wild Fund for Nature Letters, 27 May) makes a number of sensible points in response to my Forum piece (29 April). The problem is that obvious common-sense lobbying hasn’t actually brought governments to agree on constructive action.
Given the faith among governments in free-market solutions, it seems helpful to suggest a possible market mechanism of individual “Fossil Fuel Quotas”. These recognise that no national government compels its citizens to buy gas-guzzlers rather than bikes and public transport passes, to live where they must drive to reach work and shops, to rely on air conditioning and central heating rather than demand energy efficient house design, to fly halfway around the world for a holiday or business meeting 鈥� and so on.
It is true that governments, while paying lip-service to “the market”, refuse in practice to embrace the disciplines needed to correct the manifold market imperfections of the real world. The need to “internalise external costs” 鈥� to bring into the price mechanism currently unmet and unaccounted real environmental and social damages 鈥� is one of these market imperfections.
Like other proposals for tradable quotas within a sustainable supply limit, my piece sketched out what is needed for a sustainable market mechanism. If governments baulk at implementing any such price mechanism, then the argument for control by regulation is strengthened.
While debate attempts to unravel the voodoo from the economics of tradable carbon dioxide permits, a small charity by the name of Tree Aid is offering a practical carbon dioxide sink service to individuals and businesses.
Anyone who wishes to recapture their CO2 emissions can use our form to calculate their tonnage, and can send us an annual sum of 拢2 per tonne, which is 拢23.20 for the average person. We will pass it on to socially and environmentally beneficial community-based tree planting schemes in the Sahel region of Africa. Village communities gain in many ways from the trees they plant and we benefit by sinking our CO2 鈥� so everybody wins.