Editor's pick: In praise of pasture for our pastrami (1)
Articles espousing the meat-is-bad-for-the-environment point of view often assume that the meat is all from grain-fed animals (5 May, p 30). Those fed on pasture must have a lower carbon footprint, since this uses less chemicals, grain or supplemental water. Such farming largely uses land that would be unsuitable for arable crops. Yes, we should minimise consumption of grain-fed livestock. But producing the ingredients in fake meat requires higher-quality land and most likely more fertiliser and other agricultural chemicals than grass-fed livestock.
Editor's pick: In praise of pasture for our pastrami (2)
Niall Firth writes that “livestock graze on a quarter of our planet's ice-free land.” Could all this land produce crops? Not my pastures. They support a stocking rate of only 2.8 hectares per “cow unit” – a 450-kilogram cow with late winter calf. Some US ranches must allow as much as 16 hectares. These cattle must have good legs: it can be a long way to water. They are the only way to “harvest” this land.
When the birds got their bird-like hip joints
The article on dinosaur taxonomy was very interesting (5 May, p 38). Can you explain why the sparrow is deemed to have non-bird-like hips? Do the other birds know?
The editor writes:
• We're so glad you asked. We used sparrows to illustrate all birds, which belong to a branch of lizard-hipped dinosaurs that later evolved bird-like hips – in a classic case of convergent evolution.
First class post – 2 June 2018
Asking how QM ‘really’ works reflects a need for a classical deterministic reformulation Patricia Schwarz why people can't just accept quantum mechanics and stop asking “what is real?” (19 May, p 44)
We can't be sure what's in a 'brain' in a dish
Alex Pearlman says that the chance of a “mini-brain” grown in a lab being sentient in a human way is slim (5 May, p 26). But how can anyone know that? I am sentient and I can tell you that I am so because my brain is connected to devices that enable it to communicate with its environment. Mini-brains made of living human brain cells have no such connections and therefore no such ability to communicate – but to infer from this that they do not have awareness is surely an unacceptable leap.
The natural ups and downs of oxygen
You say that “along with other land plants, trees supply around half of the oxygen entering our atmosphere” (12 May, p 3). That seems to suggest that trees yield a useful net gain in oxygen and a significant net deduction from carbon dioxide. But when they rot or are burned, they consume oxygen and release their carbon content as carbon dioxide.
Talking of things in this way risks giving a false impression that, as a result of tree growth, things are not so bad as they really are. It would be interesting to see a figure for any net gain in oxygen and net loss in carbon dioxide occurring as a result of natural processes, compared with the overall net gain in carbon dioxide through burning fossil fuel that is now causing a dangerous degree of global warming.
The editor writes:
• It's all about rates of change. Burning fossil fuels contributes to a small measurable decline in the amount of oxygen in the air (17 July 2010, p 37). This is slower than expected, probably because plants are enjoying a brief CO2-fed bonanza, increasing total biomass on the planet and pumping out extra oxygen. This probably won't last. Studies of Earth's past suggest that total biomass is likely to decline as global warming continues.
Hoping that not all plants respond the same way
You report research finding that grassland plants that have the “C3” carbon fixation pathway generally produced less biomass under higher concentrations of carbon dioxide (28 April, p 15). This does not necessarily mean that the world's plants will produce less biomass with higher CO2, even if most plants are C3. Not all C3 plants are grassland plants like those in the experiments. Their supply of nitrogen might not be affected in the same way.
A tree is for Christmas, not just for life
Simon Usborne discussed putting a value on trees (12 May, p 32). My experience of growing the pine tree Pinus radiata shows an interesting change in its value with age. At 20 years old, it has a market value of around A$20. Sold at 1 year old as a Christmas tree, its market value is around A$100.
Synthetic cannabis is quite another matter
I have been involved in cannabis research for about 20 years and I enjoyed Stephanie Pain's description of William Brooke O'Shaughnessy's work on it (5 May, p 42). She concludes: “We are now in a new phase of investigation with a push to develop synthetic cannabis-like drugs.” I disagree. All the current medical activity I am aware of is around developing different plant extracts and then evaluating them in clinical practice. Synthetic cannabis-like drugs are classified as new psychoactive substances and synthesised for a very different purpose.
What does Intelligence Quotient measure?
Jessica Hamzelou reports a correlation between neuronal size and IQ scores (5 May, p 6). But, whatever intelligence is, do IQ scores measure it reliably?
The format of most IQ tests favours easily measurable qualities such as speed, fine motor skills and the ability to give accurate spoken answers to factual questions. They can test short-term memory, but not long-term memory.
They cannot examine in-depth analytical skills or the ability to participate in a rational discussion, let alone originality or creativity. Someone may appear to process more slowly because they are aware of, and are examining, more options than the test-makers recognised.
We may have to retrain generations of quolls
I was interested to read about training quolls to avoid cane toads in order to rerelease them on the Australian mainland (5 May, p 10). I did wonder, however, what happens when the first generation to be released produce young.
Presumably they would need to be trained in turn? You also report Jonathan Webb saying that dingoes may need to be trained to avoid quolls. Doesn't that pose the same problem of having to repeat the process for each generation? Even if this were feasible, would it defeat the point of a reintroduction?
Ethics of unavoidable and erratic discomfort
Ray Reed suggests that if electric shock training collars for dogs are unacceptable, then perhaps electric fences for livestock are as well (Letters, 14 April). However, the two cases are completely different. An electric cattle fence delivers discomfort that restricts the animal's movement in a predictable way.
Like a scratchy hedgerow, an uncomfortable cattle grid or other physical barrier, an electric cattle fence is static, predictable and avoidable. All animals, including ourselves, learn very quickly to avoid such types of discomfort that occur as a direct consequence of our movements. In contrast, a dog can't get away from its shock collar and will be kept in a permanent state of anxiety as a result.
When memory becomes rewritable, watch out
So we have seen a signature of memories in gene activity changes, and it may be possible to create a one-off treatment that would shift a memory's genetic signature from negative to positive (14 April, p 6). While this is intriguing and the research begs for further examination, I can't help noting that any discussion of the downside is so far missing.
As with other seemingly benign technologies, the surface results are laudable. I suffer from post-traumatic stress disorder and have spent painful years in treatment. I would thrill to the notion of such a new treatment.
But I am concerned that this could “possibly even lead to treatments that alter memories”. I understand that the intent is commendable, but we have seen too many times such intent diverted for despicable application. We already live in a world in which image-based evidence is increasingly susceptible to manipulation, with falsified video showing up on popular sites (17 March, p 24).
I shudder to think what certain regimes' law enforcement and security agencies might be able to accomplish, given the tools that this research seems capable of eventually spawning.
What whales may share with Mongolian singers
Kate Stafford says that bowhead whales can produce two different sounds at once, and “we don't know how they do that” (14 April, p 20). I wonder whether the whales may be using techniques similar to those used by human throat-singers from Mongolia, Tibet and elsewhere.
These singers amplify selected overtones – harmonics of the note produced by their vocal chords – by changing the shape of their oral cavities. Demonstrations by traditional singers and others such as Anna-Maria Hefele can readily be found online.
For the record – 2 June 2018
• Down the back of the sofa: gold worth $22.2 billion was to be wasted in 2016 by scrapping all kinds of electronic goods (14 April, p 20).
• Kiersten Dobson is at the University of Western Ontario in London, Canada (Feedback, 12 May).