Editor's pick: Sight, insight and psychedelic drugs
Sam Wong reports men with colour blindness dropping out of a study on psychedelic drugs because of visual effects (17 June, p 22) and Tony Durham suggests this may inform how we see colour (Letters, 9 September). Colour blindness is a result of faulty detection in the eyes. But if the brain can still process trichromatic vision, hallucinations could appear in full colour, resulting in “seeing” colours never experienced before.
I cannot even conceive what this would be like, but I imagine it would be very disorientating.
Editor's pick: Sight, insight and psychedelic drugs
Durham's question about colour blindness and hallucinating reminds me of a story told by the late art forger Eric Hebborn about his form of colour blindness, which sometimes caused him to paint fierce greens when he thought he was using delicate greys. He claimed that after unknowingly eating cake laced with LSD and hallucinating, the colour blindness seemed to go away.
You can help re-examine Barnard's star for planets
Richard Swifte suggests resuming research on the movement of Barnard's star to see if it has a planet (Letters, 26 August). The at the European Southern Observatory's 3.6-metre telescope at in Chile is studying the movement of several close stars, among them Barnard's star. Swifte and others can contribute to checking results through the .
Hero of Alexandria's steam engine
You ask: what if the ancient Greeks had invented the steam engine (9 September, p 5)? described a sphere containing water mounted over a fire on a horizontal axis, with small jets emitting steam. It spins – he thus invented both the steam engine and the jet.
Hero of Alexandria's steam engine
You say, rightly, that if Darwin had not written the Origin of Species, evolution would still have been discovered. It is, however, unlikely that the Greeks could have invented a practical steam engine – despite Hero of Alexandria's efforts. The steam engine as we know it was invented to pump water out of deep mines. The supply of coal was the main force behind its development.
The editor writes:
We indeed meant to say that the ancient Greeks didn't invent a steam engine that could power an industrial revolution.
First class post
And suddenly, holding a hungry grandchild has become infinitely creepy…
XD that sacrificial virgin spiders let their nieces eat them alive (23 September, p 19)
Generating nuclear power also emits carbon
Eric Kvaalen points out that nuclear energy production isn't green because no way has been found to deal with the problem of nuclear waste (Letters, 2 September). Nuclear power is being “sold” to the public by saying it doesn't emit carbon dioxide. Though nuclear reactors emit little CO2 at the point of generation, they are just a small part of the nuclear fuel cycle.
Uranium mining, milling the ore, converting it to uranium hexafluoride, enriching that and fabricating fuel rods all emit large amounts of CO2. Much energy is also used in the treatment, conditioning, transport and disposal of nuclear products.
Jan Willem Storm van Leeuwen and Philip Smith that nuclear generation produces a third as much CO2 per unit of electricity generated as conventional, mid sized, gas-fired electricity generation – and more if lower-grade ores have to be mined. Decommissioning old radioactive nuclear power stations also consumes energy.
Drawing lines between interbreeding species
Colin Barras's piece on the confusing history of our species offered more evidence that evolution is a messy business, not working towards any goals (26 August, p 28). I am puzzled, however, by his conclusion that there might be no “true” Homo sapiens, because our species, Neanderthals and Denisovans all interbred. That implies there were no “true” Neanderthals or Denisovans either. “True” is unhelpful, especially when it smacks of unsavoury race theory.
Drawing lines between interbreeding species
So most non-African modern humans have small amounts of DNA from Neanderthals and some other still-exotic prehistoric humans. Reporting of this has sometimes included tales of romantic meetings between Neanderthals and modern humans. This coincides with the change in representation of Neanderthals from brutish cave-dwellers with clubs to smiling and friendly avuncular types.
Another story is possible: that interbreeding was sometimes the result of rape. I, also, like the idea of peace, love and harmony in the Palaeolithic world and prefer the thought of a smiling Neanderthal ancestor sitting by the campfire sharing the hide of a cave bear with a woman from the new tribe. Both stories might be true, and likely were.
Are teenagers just trying to cram too much in?
Russell Foster suggests that teenagers' late waking relative to adults means they should start school later (9 September, p 26). It isn't at all clear to me whether this is caused by biological processes or is just the result of regularly staying up too late.
Humans aren't adapted for nocturnal living, and it would surprise me if there were truly a biological reason for teenagers' habits, rather than it just being their wish to fit more into every day than there is room for.
Foster hints at the latter, in which case we would be crazy to pander to them. Is there any evidence of similar behaviour in adolescents in earlier times or in cultures where the concept of “teenager” was or is unknown?
The editor writes:
There is some evidence for nocturnal living, for example the finding that in Hadza hunter-gatherer camps there is always someone awake (15 July, p 10), and in a reassessment of the “second sleep” in early modern history (30 November 2013, p 36).
Seeing eye to eye on eardrum movement
Aylin Woodward reports that our eardrums move in sync with our eyes (29 July, p 12). But given that the changes in the eardrums start before the eyes move, isn't it possible that hearing triggers the eye movement? This makes intuitive sense: we tend to shift our gaze towards things we hear.
So what's so new about this genome project?
You report on the UK's 100,000 Genomes Project and concerns over data privacy (2 September, p 22). This reminded me of the UK Biobank (7 April 2012, p 8). It has 500,000 members and, apart from blood, is interested in things such as lifestyle. What is the extra benefit of the new project?
The editor writes:
The UK Biobank . The collects whole DNA sequences.
There is dispute over the safety of statins
You state that statins are a safe way to reduce cholesterol levels and prevent heart disease (26 August, p 5). But in 2015, David Diamond and Uffe Ravnskov published a bone-chilling study titled “How statistical deception created the appearance that statins are safe and effective in primary and secondary prevention of cardiovascular disease” (Expert Review of Clinical Pharmacology, ).
There are many types of earthquake zone
John Pickrell's description of the use of interferometric synthetic aperture radar to study earthquake zones was interesting (2 September, p 40). He notes that earthquakes are generated where tectonic plates move against or away from each other.
There's a lot more to it than that. Plates move apart in places such as the Mid-Atlantic ridge where new crust is formed. Where two oceanic plates converge, the older, colder and denser one descends below the other in a process called subduction, such as where the Pacific Plate is sliding beneath the Philippine Plate. Where an oceanic plate converges on a continental plate, it is subducted, as where the Pacific Plate is subducting beneath South America. Where two continental plates converge, neither is subducted and immense crumple zones result – for example, the Himalayas. Earthquakes are generated in all these situations.
They are also generated where two plates slide past each other, as with the Pacific and North American plates – the San Andreas fault is the prime example of this. And many earthquakes occur well away from plate boundaries.
Listen: transistors do analogue work too
Liesbeth Venema says transistors are “electrical switches that either allow current to flow or not, and nothing in between” (5 August, p 33). In digital circuits, transistors are generally switched “full on” or “full off”. But in general they modulate the output current by varying the input signal in an analogue fashion – as utilised in amplifiers, analogue radios and many other devices.
Going out on a limb over dodos' layout
You report that the life cycle of the extinct dodo was worked out from analysis of 22 bones, all but one from the hind legs (2 September, p 14). The biggest surprise must have been the discovery of the hitherto-secret front legs.