Editor's pick: Antibiotic crisis long in the making
Why has it taken so long for the “antibiotic apocalypse” (21 March, p 22) to get a hearing in policy-making circles? I started my training as a nurse in 1968. Though we did not have to learn about the biochemistry and pharmacology of antibiotics and of course did not prescribe any medications, we certainly learned about the practicalities of antibiotic treatment.
We were taught that, in any case of infection, it was good practice to identify not only the bacterium responsible but also its sensitivity or otherwise to a range of antibiotics; and that we should do this rather than prescribe a “broad-spectrum” antibiotic.
We learned that it was preferable to prescribe a course of antibiotics over a set number of days rather than (as many doctors did) “prescribe and forget” so that patients could be receiving the same antibiotic for two or three weeks, whether they needed it or not.
We also knew that combining two antibiotics made it more difficult for bacteria to become resistant to either. And we were taught that bacteria could develop resistance to antiseptics as well as antibiotics.
The medical profession has known about antibiotic resistance for the best part of half a century. What have they done about it? Not very much.
Whittlesey, Cambridgeshire, UK
Laying ground rules for free will
Randomness is not by itself sufficient to “admit free will” in an otherwise mechanical universe (14 March, p 28). At a minimum, free will requires that the outputs of my brain are not completely determined by the inputs plus the initial state. This is unlike any other known physical system or law. Introducing randomness merely allows for a range of outcomes distributed probabilistically, but still with no element of intentionality or purpose 鈥� the other essential ingredient in free will.
One intriguing possibility is that whatever free will might be, randomness provides a means for it to influence the brain without apparently violating known physical laws over the long term. Such a brain would be like a rigged roulette wheel that comes up red or black at the casino’s choosing, but must still ensure that the two come up equally over the long term if it is not to be caught breaking the rules.
Some experimental results are consistent with this model. For example, behaviours that we usually consider as exercising free will, such as paying attention or resisting temptation, can be exhausted. This is despite the fact that they don’t seem to be associated with anything as obvious as depletion of neurotransmitters. This is what we expect if free will can only influence a limited number of outcomes while staying hidden within known physical laws.
Whatever free will turns out to be 鈥� assuming it exists at all 鈥� understanding it will take at least as great a conceptual leap as that from classical mechanics to quantum theory. And perhaps it is only chance that binds these three views of reality into a consistent, scientifically explicable universe.
Waterford, Virginia, US
Laying ground rules for free will
I suggest another definition of free will: that people have free will because they can make conscious decisions that can neither be predicted, with absolute certainty, by any other person nor be dictated, with absolute certainty, by another person.
It is irrelevant that these decisions are made by our brains, which are part of the physical world and controlled by the laws of nature and therefore predictable, in principle. For a computer to make such a prediction, it would have to be as large and as old as the universe.
A clear definition removes the conflict between determinism and free will and may let us get on with more relevant and interesting discussions.
London, UK
Green spirits soar on coal bust
Fred Pearce describes how a “coal bust” may be behind the stall in carbon emissions (21 March, p 16). Thank you for publishing an item that keeps hope alive and gives we Greens cause to celebrate.
Bakersfield, California, US
Weekly social
“Nothing is certain 鈥� not even the uncertainty principle”
Waseem Lone posts last month in response to “celestial signals that defy Einstein” (4 January 2014, p 30)
Infinite planet and our false economy
I am interested that Andy Haldane of the Bank of England now looks to several scientific “ologies” for guidance (28 March, p 28). But your interview does not mention any questioning of the base assumption of the present economic system: namely that we inhabit a world of infinite resource in which pollution has no consequences. Perhaps he also needs to consult a class of 5-year-olds for advice!
Keyworth, Nottinghamshire, UK
Food fit for a Red Queen
Isotopes in dental enamel from the Red Lady of El Mir贸n revealed that 80 per cent of her diet was meat from hooved animals, the rest being fish, some starchy material, seeds and mushrooms (21 March, p 8). You describe this as “the Paleo diet, for real”. The Red Lady was, however, no ordinary woman.
The circumstances of her burial were exceptional; she was painted in red iron oxide pigment. She was probably a queen or a leader.
Last year, isotope analysis of bone and tooth material from King Richard III that he ate swan, crane, heron and egret and drank plenty of wine. That would hardly have been the typical diet in medieval England.
Bristol, UK
Perceptions of probability on trial
Regina Nuzzo gives a fair account of the conflicts between frequentist and Bayesian statistics (14 March, p 38), and I agree with the conclusion that applied statisticians generally combine both approaches. The starting point of frequentist statistics 鈥� the “null hypothesis” with which results are compared 鈥� is generally a straw man. The anticipation of finding a relationship when we choose what data to collect echoes the Bayesian “prior probability”. A bigger issue is the untestable assumption that the data form a representative sample of a wider population or distribution.
It would be interesting to know, as a case of everyday Bayesianism, the prior beliefs that people bring to courtrooms. What do jurors think before the case has started? The presumption of innocence cannot correspond to zero probability of guilt. Prosecutors decide to bring cases based on an estimated “reasonable probability” of conviction.
I hope that each juror starts with a personal estimate of the probability of guilt before hearing evidence 鈥� informed, for example, by the proportion of prosecutions that lead to guilty verdicts. They can then evaluate the evidence to compare the likelihoods under hypotheses of guilt or innocence, arrive at a probability of guilt, and compare that with their personal standard of what is “beyond reasonable doubt”.
The law in the UK does not allow observation of the jury process to test that explanation. My personal prior belief is that it is hopelessly optimistic.
Forston, Dorset, UK
When charity goes wrong
It is always depressing to read about humanity’s apparent complete inability to learn from its own mistakes, and Simron Jit Singh’s account of inappropriate disaster relief is a prime example. (21 March, p 34).
It reminds me of when the so-called EMI scanner was marketed in the early 1970s. Groups sprang up in the UK to raise funds to buy one of these new wonder machines for their local hospital.
The machine was an axial tomographic unit using X-rays. It was only large enough to take a patient’s head. Nonetheless it was universally hailed as the answer to diagnosing all brain disorders. Many scanner appeals were organised without consulting hospitals, which were then presented with machines with very little prior warning.
I know of one scanner that was duly delivered, but then stayed in its packing crate for at least two years in a major hospital’s basement store. When it disappeared, rumour had it that managers had sold it to another hospital that actually wanted it. The first hospital had nowhere to install the scanner and no staff to run it, or available for training. They also couldn’t afford to pay the running costs or for its eventual replacement.
Such stupidity never occurs these days, because philanthropic organisations have learned to work with local equipment purchase prioritising schemes, and only buy what the professionals have agreed they want and need.
How very sad to read that, presumably, highly organised professional relief organisations have yet to learn that simple lesson from the UK health service of 40 years ago.
Glasshouses, West Yorkshire, UK
Enceladus's mystery heater
Saturn’s moon Enceladus is getting attention as a possible venue for life. Last year you reported that “as Enceladus orbits Saturn, changes in the planet’s gravitational pull flex the moon, but… a stiff rocky core would not flex enough to generate the heat necessary to melt the ice”. But when researchers modelled a core “more like a snow cone than a stone, it flexed and created enough heat to fuel its famous water jets” (1 November 2014, p 17).
Now Hsiang-Wen Hsu of the University of Colorado thinks that “tidal heating, generated by the squeeze of Saturn’s gravity, wouldn’t provide enough energy” for chemical reactions producing sand grains ejected into Saturn’s rings (14 March, p 11).
Does this imply an as-yet-unknown alternative source of heat? I would be fascinated to read more about the convergences and differences between the findings of these two projects.
Wallingford, Oxfordshire, UK
Enceladus's mystery heater
鈥� So would we, and we also look forward to finding out whether both reports are true, and how.
Lights! Camera! Metamirror!
Metamirrors that reflect face-on light at 45 degrees (14 March, p 16) are not quite new. Whenever an actor shaves or does their hair in a mirror, how do you think the camera (at an angle) manages to capture them face-on when they are shown apparently looking at themselves?
Exmouth, Devon, UK
For the record
鈥� Flaring off 10 million cubic metres of methane gas will produce about 18,000 tonnes of carbon dioxide (28 March, p 20).
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