<i>The editor writes:</i>
鈥� Mu帽oz’s fetus was not viable. The on the orders of a state district judge.
For the record
鈥� We briefly lost our bearings in our look at Braess’s paradox (18 January, p 30). Physicist Adilson Motter is at Northwestern University in Evanston, Illinois, not Northeastern University.
Gut rumbles
Cryan and Dinan show that our gut flora powerfully affect us. Despite some counter examples 鈥� infections and the success of faecal transplants 鈥� our flora seems to be either self-managing or managed by us, for example through diet. It would be good to know how much of which, and whether we can intervene in the latter process to our benefit.
Great Missenden, Buckinghamshire, UK
Gut rumbles
John Cryan and Timothy Dinan’s article on the links being demonstrated between various psychological problems and particular strains of gut bacteria is encouraging in its suggestion that these may provide future treatments (25 January, p 28).
However, the jump to suggesting that the ideal treatment may be a genetically modified organism containing genes from several different bacteria seems an unnecessarily complicated solution, given that the strains of bacteria mentioned in the article already exist. To my knowledge, all, or almost all, of these are already available in forms which survive stomach acid, and different strains can be used together.
The only obvious advantage of genetically modified versions appears to be for commercial companies to patent them.
Northampton, UK
Symphony in 3D
I was fascinated to learn about Markus Buehler’s use of musical structures to improve the design of materials (1 February, p 30). That set me thinking: what novel structures and materials might already lurk undetected in the huge library of musical compositions? I feel an app coming on, for hooking up a 3D printer to your hi-fi to see what comes out.
Burwell, Cambridgeshire, UK
Stress link
Liam Drew’s article advising of a decline in dementia rates is welcome news (11 January, p 32). I’ve worked for four years in caring for older people. Daily I see the ruination of lives that dementia brings.
I’m convinced that high levels of stress hormones, called corticosteroids, are responsible for the ravages to the brain characteristic of both vascular dementia and Alzheimer’s disease. The most well-known symptom of dementia 鈥� short-term memory loss 鈥� is caused by corticosteroids inhibiting glutamate uptake in the hippocampus. The at Stanford University on this is informative.
Wollongong, New South Wales, Australia
Slow lane
Alan Coulson says his Morris Minor car could evade a new system that disables the vehicles of uncooperative drivers by firing radio pulses at them (25 January, p 31). I also own one, but would like to note that Morris Minor drivers are seldom the target of a police pursuit and in any case have considerable difficulty in achieving escape velocity.
Yeovil, Somerset, UK
Let them eat salad
The crops listed in your article championing the urban vertical farm as a “new, environmentally friendly way to feed the rapidly swelling populations of cities worldwide” are lettuce, spinach, kale, tomatoes, peppers, basil and strawberries (18 January, p 17).
Tasty, but no rice, wheat, maize or potatoes. Sounds more like garnishings for the wealthy than a way to feed cities.
Frome, Somerset, UK
Genetic pointer
I used to reject the concept of intergenerational memory transfer that John O’Hara highlights in his letter (18 January, p 29). Then I woke up. I have a pointer, my fourth. These dogs were bred to find birds, and then on command, get the birds to break cover so they could be shot. None of my pointers were trained to hunt, as I don’t hunt, but all of them know what to do.
They are born obsessed with finding birds. When they find one they stalk it like a cat. When close enough they take up a “pointing” position that never varies, with one paw raised and the tail horizontal. The only explanation is that the behaviour is passed on by the genes. Intergenerational memory is there to see. If anyone doubts it, get a pointer.
Condom, France
Multiverse musings
While we don’t know whether parallel universes exist, there is something we do know: whenever a physicist writes a book about them, the web erupts with claims they are unscientific nonsense.
Mark Buchanan’s review of my book was no exception (18 January, p 46). “Is this still science,” he wonders, “or has inflationary cosmology veered towards something akin to religion?”
The key point that many critics miss is that parallel universes aren’t scientific theories, but the predictions of certain theories, such as cosmological inflation. These theories are scientific because they make testable predictions for things that we can observe, such as the cosmic microwave background.
Because it has passed such experimental tests, inflation is the most popular theory for what happened to the universe early on. But if we take inflation seriously, then we must also take all of its predictions seriously, even those that are untestable 鈥� including parallel universes.
Humans have repeatedly underestimated the size of our cosmos by assuming that everything we could observe was all that existed. No matter how seductively comforting a small reality may feel, we aren’t free to opt out of scientific predictions because we don’t like them. Our job as scientists isn’t to tell the cosmos how to be, but to follow the trail of evidence wherever it leads. For a further discussion see my blog at .
Cambridge, Massachusetts, US
Tragic choices
Based on the assumption that brainstem death means life has ended, I would draw the opposite conclusions to medical ethicist Richard Huxtable in his look at the debate over life support for pregnant Marlise Mu帽oz and teenager Jahi McMath in the US. Both were diagnosed brain dead (25 January, p 26). There was a moral duty to continue life support for Mu帽oz’s body because of her unborn child. Her autonomy or wishes shouldn’t have entered the discussion, as she no longer “existed”.
As for McMath, there is no reason her family should be prevented from carrying out their wish to keep her body on life support, so long as it is at their own expense. Ethically, it is no different to preserving the body by embalming it (though more expensive and less permanent).
It seems that deciding at what point life ends is the beginning, not the end, of this debate.
Cardiff, UK
Super sonic?
The notion of using high-intensity focused ultrasound waves in cancer surgery sounds interesting (4 January, p 38). However, as a pathologist, I have some concerns.
You can make a case for sonic waves cooking an in situ tumour to oblivion, but in practice the inspection of a removed tumour remains important in order to check for a sufficient rim of healthy tissue to verify success. A blind roasting of the cancer gives no such assurance.
The period of post-surgical surveillance is where ultrasound treatment may be at its most beneficial. So many cancers end up evading the scalpel and shooting out metastatic seeds. A two-pronged assault would be good: a sensitive imaging technology that can pick up small metastatic deposits, followed by focused ultrasound bombardment to fry them. Add appropriate chemotherapy and you could be weeding the corporeal garden on a regular basis, prolonging life to who knows what extent.
Vancouver, British Columbia, Canada
Potty mouth
I enjoyed the article on nitrogen-hungry pitcher plants and their relationship with defecating mammals (1 February, p 43). But I am not 5 years old so don’t need the prissy and childish word “poo” to assault my eyes.
Excreta, faeces or droppings are perfectly acceptable; dung is perhaps not, as it implies manure.
Shit was originally used without any connotation of vulgarity and should re-enter respectable society. But, please, not “poo”. What next? Articles on genitalia using such euphemisms as “front bottom”, “naughty bits” and “meat and two veg”?
Felpham, West Sussex, UK
Road to Damascus
Discussing Fyodor Dostoevsky’s epilepsy, Anil Ananthaswamy asks if mystics through the ages had comparable “ecstasies” (25 January, p 44).
Seven decades ago, historian Joseph Klausner’s book From Jesus to Paul outlined reasons for thinking that St Paul had epileptic seizures. In 1987, David Landsborough developed this diagnosis in the , and in 2003 the idea caused “offence” when voiced during a BBC1 documentary on the origins of Christianity.
Sheringham, Norfolk, UK
Fructose effect
I enjoyed your look at sugar’s health effects, and was fascinated by the statement that “fructose doesn’t affect leptin production [the hormone that makes you feel full]; one small study even suggests it ups the level of its counterpart ghrelin, the hormone that makes you hungry”. In other words, fructose encourages overeating (1 February, p 34).
This fits my experience while at boarding school where the diet was biased towards sweet puddings, white bread and jam 鈥� all filled with this sugar. I spent four years putting on weight in term time and I was also permanently hungry.
Seaview, Isle of Wight, UK
Human nature
In her letter, Weibina Heesterman fears that new life forms evolving after a human-induced mass extinction event “might be a glut of insect forms rather than cuddly koala-type creatures” (1 February, p 33). Yet the evolution of new species of insect and other invertebrates would hardly be surprising considering that they will also be severely affected by a mass extinction.
It doesn’t help that the plight of endangered insects, molluscs and other invertebrates is ignored in the rush to protect a handful of charismatic species, nearly always mammals or birds.
Insects are complex, varied and fascinating, yet many potentially avoidable extinctions will occur if the attitude persists that only cute, fluffy animals matter. We need to encourage an appreciation of life’s true diversity.
Brisbane, Australia
Human nature
The views of ecologist Chris Thomas on the resilience of the biosphere were refreshing and long overdue (11 January, p 28). As he points out, extinctions, hybridisations and the generation of new species are fundamental to the constant fine-tuning of Earth’s biosphere, and offer some consolation in the face of fears of species decline.
The changes we cause should be seen as part of the dance of nature, as much a part of it as the fall of an asteroid 鈥� although they are infinitesimally less significant.
London, UK