The lynx effect
The suggestion that the lynx should be reintroduced into the UK is a sensible one, and not just because it was demonstrably exterminated from these islands in the early Middle Ages (11 August, p 48).
Here in rural Oxfordshire the deer problem is becoming acute: principally the roe and the wretched muntjac (an unauthorised import released/escaped into the wild) which are systematically destroying forest and woodland ecology. Their relentless eating is preventing the undergrowth regenerating and saplings from growing. They are destroying quite significant trees by fraying the bark. In short, they are a major pest and are growing in numbers across the UK because they do not have a superior predator to control them.
The Eurasian lynx’s main diet in Europe is the roe deer along with chamois. Like its smaller cousins the Canadian lynx, which survives exclusively on snowshoe hare, and the very rare Iberian lynx, which predominately eats rabbits, it also takes smaller prey.
The lynx would seem to be an ideal solution in terms of deer control. It is a creature of the forests, not open moorland or plains, so it is unlikely to be a major problem for sheep farmers. Additionally, being a very secretive cat needing large areas to roam, it is unlikely to be in conflict with people; in any event they have never been known to attack humans. The lynx is not a large creature, averaging around 25 kilograms. Compare this to a hypothetical suggestion of reintroducing the wolf, which hunts in packs and has a much worse history of human interaction: you can imagine the protests 鈥� and not just from the farmers.
The only real problem would be if the lynx became too successful 鈥� in which case we could reintroduce the bear to control the lynx population.
A bridge too far
The safety tests proposed and being carried out on bridges are clearly warranted (11 August, p 3). That leaves the question, will they detect the effects of resonance?
Those interested in this subject should watch film of the 1940 Tacoma bridge disaster to see the fantastic movements of the whole structure caused, apparently, by wind resonance: YouTube has a with newsreel-style commentary and a .
And they may remember the vibrations in London’s . It seems worthwhile to mention that, depending on the details of construction, only sections of a bridge may resonate at particular frequencies.
Spooks from space
Mason Inman reports that there is concern over whether “typical” observers of the universe are entities like ourselves 鈥� who depend on a universe in which we have evolved and that provides life support 鈥� or “Boltzmann brains” that pop out of the universe fully formed as a result of fluctuations in the quantum vacuum in a universe of eternal inflation (18 August, p 26). Such brains presumably could also pop into existence with memories based upon their physical structure, so how do we know that we are not ourselves Boltzmann brains?
Indeed, if we allow the possibility of Boltzmann brains, some of those that pop into existence might do so with memories of a lifetime of earthly existence followed by a paradise. Could this pose a problem for Richard Dawkins?
From Greg Egan
In their paper “Are We Typical?” (), James Hartle and Mark Srednicki explain very clearly why there is no guarantee that we are typical observers. There might or might not be any number of Boltzmann brains in the far future, but deriving cosmological parameters on the basis that beings like us “must” outnumber them has no basis in logic or science.
Tuart Hill, Western Australia
From Nick Herring
The idea of Boltzmann brains popping out of nothingness to give us the heebie-jeebies surely belongs in The Hitchhiker’s Guide to the Galaxy rather than a high-energy physics journal. There might be a minute but finite probability of one being created out of a vacuum fluctuation, but surely the energy debt would be so huge and short-lived that nothing as fragile as a brain could possibly survive long enough to observe anything.
Disregarding, for a moment, such trivial matters as the known laws of physics and biology, then in an infinite number of possible universes there must be an infinite subset where, for instance, ruminating sperm whales and bowls of petunias impudently appear together out of the quantum vacuum without so much as a by your leave.
London, UK
The editor writes:
鈥� Sure, the idea of Boltzmann brains (BBs) is absurd 鈥� to minds like ours that can’t grasp the concept of infinite space and time. Yet mainstream cosmologists are taking it seriously. Keep in mind that BBs need not be actual brains 鈥� just conscious observers of some sort. It is infinitely unlikely, in fact, that they would be anything like us. As for the assumption of typicality, it is built deeply into many aspects of science, and most cosmologists do not think we should banish it 鈥� though there is certainly no guarantee that we are typical. More letters on this next week.
A bridge too far
You suggest sensors to monitor bridges (11 August, p 3). But critical connections can have problems with corrosion, fatigue, under-design or a combination of these, which can escape inspectors and sensors and cause sudden collapse.
Early in my engineering career I had to extend a crane runway. When we opened apparently sound bolted joints we found that the bolt shanks inside were seriously corroded.
Later I designed a system of test loading for bridges under construction or in service. This involved driving a convoy of empty tankers onto the bridge, after which everyone would leave the structure. Water would then be pumped into them 鈥� up to 25 per cent more than the bridge’s design load 鈥� while the sensors were monitored for any non-linear behaviour. That would be taken as a signal to dump the water and find the cause.
Bridges are designed to stay up when subjected to at least 50 per cent more than their service load, so no damage should result. Too bad if the bridge does collapse, but at least no lives would be lost.
For some reason this did not appeal to bridge authorities.
Sensor systems themselves carry a risk. Any system that is seen as self-monitoring becomes trusted to the extent that, like most displayed notices, it is never read. They are only as good as the people charged with monitoring the monitoring system. These people can become ill, grow careless or exhibit the contempt that is acknowledged to grow from familiarity.
Cancer urgency
Jim Tassano of dichloracetate (DCA) fame is right when he says that there are many other substances out there that have shown promise in cancer treatment but are unlikely to be put through expensive testing because they cannot be patented (18 August, p 44).
I am a colon cancer survivor (so far, two years on), and have low-level chronic lymphocytic leukaemia. I am also a Cambridge science graduate, and I can report that attitudes to risk and to data assessment change on getting a cancer diagnosis.
Many cancer drugs are hugely ineffective. The additional survival advantage conferred over five years is generally reckoned to be 3 to 5 per cent, and many are themselves carcinogenic. Reading data like that leads to the feeling that there must be something out there that can do a lot better.
As soon as I was physically and mentally able after the operation on my cancer, and in the midst of chemotherapy, I researched more than 100 substances that had shown anti-cancer promise at some stage in their testing, or helped people get through the so-called side effects of chemotherapy. With the help of other informed people I put together of the best of the bunch.
I bet that the survival advantage over five years of the 10 or 15 most hopeful substances would be a heap better than the measly benefit of systemic chemotherapy. The mix could be given with standard cancer treatment. With central bulk purchasing it would cost no more than 拢200 to 拢300 a month for each patient.
I wonder whether a new kind of power-to-the-people research study protocol could be implemented over the internet. Doctors and researchers who wanted to participate could do so, inputting their own data online. It would certainly help improve the lives, and could save the lives, of thousands of cancer sufferers.
Satellite gone
You report the temporary naming of Saturn’s 60th moon as “Frank” (28 July, p 7), but nobody seems to have picked up on the slightly macabre origin of the joke.
Remember the image of Frank Poole spinning away from the spaceship Discovery One in the film 2001: A space odyssey?
In the book this was on a mission to Saturn, though not in the film.
Burning bush
Caroline Williams reports on an interesting hypothesis about bush fire behaviour, suggesting that the accumulation of flammable gases ahead of the fire may explain why fires can unexpectedly shoot forward large distances (4 August, p 38).
This idea, however, conflicts with the fact that because of the buoyancy of heated gas the one place that these flammable pyrolysis products cannot be found is downwind of the fire front, as the article itself reports Janice Coen as pointing out.
Immediately downwind of a large, intense bush fire is a zone of relatively still, smoke-free air in which ambient wind is blocked by the fire and its convection column.
In this zone, firebrands falling out of the convection column ignite spot fires that spread as circles.
When biomass is heated in a fire, the primary pyrolysis product is laevoglucosan (1,6-anhydro-beta-d-glucopyranose), which further degrades to generate much of the gas that then oxidises to form what we see as flames.
Laevoglucosan has a melting point of 150 掳C to 180 掳C. If a lack of oxygen leaves it unburnt, it contributes to the dense appearance of the smoke that rises from the fire, which if carried away from the fire will rapidly cool and condense as a tarry residue.
While some of the degradation products of laevoglucosan may remain gaseous away from the fire, entrainment of ambient air will quickly cool the gases to well below their ignition temperature 鈥� which is, incidentally, typically 300 掳C to 350 掳C, rather than the 1200 掳C reported by Williams, which is the flame temperature.
The turbulent flows associated with bush fires, quickly disperse these gases, so there is no opportunity for combustion, explosive or otherwise.
Stomach upset
Taken together, two of your recent articles give pause for thought. The feature entitled “Bugs R us” reports that we humans have recently begun drastically altering the types and proportions of bacteria in our guts, reducing the incidence of Helicobacter, for example (18 August, p 34). Children acquire the adult mix of gut bacteria by about age 2. Reduced or abnormal gut flora may increase the incidence of bowel inflammations such as Crohn’s disease.
A short article three weeks earlier (28 July, p 18) reported that regressive autism seems to have become much more common recently and becomes apparent around age 2. It has been provisionally linked to a form of bowel inflammation and immune system malfunctions. In the furore resulting from the now discredited idea that MMR vaccine was involved, no one seems to have paid much attention to the suggested link with bowel inflammation.
Is it possible, therefore, that replacing the flora that was usual in previous generations of 2-year-olds with the modern mix of gut bacteria might both promote inflammation and be connected to the onset of regressive autism in genetically predisposed children? Speculative, but possibly worth investigating. Or has it already been investigated?
The editor writes:
鈥� We have covered such research 鈥� see for example the feature “Gut reaction” (20 June 1998, p 42).
Climate uncertainty
Lenny Smith and Dave Stainforth are correct to note the large uncertainties in regional projections of climate (18 August, p 13) and we at the Met Office share some of their concerns. However, there are those in government and industry who have to make decisions today about long-term infrastructure and who cannot wait until regional predictions are “nearly perfect”. For those who have to make decisions now, we believe it is better to base those decisions on current imperfect models rather than on no information at all, provided the associated uncertainties are made clear.
Nowhere do we assert that current predictions are nearly perfect; we seek instead to make transparent the level of uncertainty. One should not overstate uncertainty, however. Some features in current predictions for the UK are expected on physical grounds and are consistent across a range of models, including significant warming, rise in sea level and increased winter rainfall.
The Met Office is to the fore in quantifying the uncertainties, and works with the climate science community to reduce them through improving the physical basis of climate models. The aim, as ever, is to ensure that government and industry have the best available climate advice to guide future investment.