Editor's pick: A significant source of earned dogmatism
David Robson describes “earned dogmatism” as the tendency of a person to overestimate their expertise based on past training (23 February, p 30). I used to advise PhD candidates as a statistician, and was particularly aware of examiners from many disciplines who claimed sweeping knowledge of statistical methods, apparently based on an introductory course in the subject taken a long time ago or on having analysed their own data for years.
A particularly memorable example was a PhD student who was told after their oral “viva” examination that their thesis was sound but their statistics must be reworked using a different kind of method. The student accepted it was easier and quicker to comply than to challenge this verdict. The reworking changed no results.
Scientific papers, refereed by experts in their field of science, get published with glaring statistical flaws. I have yet to find a journal editor who admits that the statistical treatment of data should probably be refereed by a competent statistician.
Pension divestment can combat climate change
Students in over 100 towns and cities in the UK took part in the global Youth Strike for Climate on 15 March, inspired by Greta Thunberg (16 March, p 7). Many may not be aware that their schools and sixth-form colleges may be funding businesses linked to climate change through their payments to pension schemes.
Pension schemes run by local government are estimated to have 拢16 billion invested in oil, coal and gas companies. In East Sussex, a Freedom of Information Act request that in excess of 40 local schools and colleges together contribute at least 拢9.8 million a year to the East Sussex Pension Fund, which in fossil fuel firms.
By taking action in schools to get pension schemes to support divestment from fossil fuel companies, students, parents, teachers and staff can help to break the hold that these firms currently have on economies and governments around the world, and make way for a transition to renewable energy.
First class post 鈥� 30 March 2019
I generally recommend you breathe in every once in a while
Sabine Hossenfelder with a finding that breathing in before doing something may make you better at it (16 March, p 8)
How male and female brains may differ (1)
Gina Rippon makes the points that men and women are more similar than they are different and that every person's brain is unique (2 March, p 28). She concedes that the sexes differ statistically in preferences, behaviour and abilities.
How can these slight but observable differences be explained? Rippon entertains only two possibilities – genotype and the influence of stereotype – and implies that these are in opposition, thereby perpetrating a neat binary division of her own. Surely the boundary between the two is fuzzy, and surely there are other contributing factors.
Two spring to mind. One is the impact of childbearing on women's lives. The other is the fork-in-the-road effect, in which a marginal initial preference is amplified by vocational choice into a life-determining result. Multiply this scenario many times over, and you can get a divergence that is statistically significant.
How male and female brains may differ (2)
When considering sex differences, we must take into account the brain being bathed in hormones, including testosterone and oestradiol, which occur in very different amounts in most men and women.
Cases of surgical and chemical castration, and of testosterone supplementation, show that testosterone levels affect behaviour, emotion, personality and cognition. In addition, the brain is constantly exchanging signals with parts of the body, including those specific to our sex. Tiny differences in brain structure or connectivity could produce significant differences in function. I think we need to keep an open mind regarding sex differences of embodied brains.
Some particles may be more equal than others
Brian Pollard reminds us that atmospheric particulate pollution from cars comes from the tyres and brakes as well as exhausts (Letters, 2 March). Particles are responsible for most of the loss of life expectancy associated with air pollution. What concerns me is that the word “particle” is being used to cover a multitude of sins.
Petrol cars produce a lot of exceedingly small (30 nanometre) carbon-based particles. Diesel cars made since 2011 release mostly droplets of engine oil and nitrate particles. All car brakes release particles of iron, iron oxide and resins; and tyres emit particles of rubber, carbon and silica.
It seems unlikely, given the huge range in both size and nature of particles, that the standard measurement of air pollution – weight of particles per cubic metre – is a meaningful guide to their harmfulness to us.
One might guess that smaller particles will be more harmful because there are more of them per gram and they will be able to enter the human body more easily. What data do we need to make meaningful decisions?
Great goblets of fire in several ages past (1)
You report a 3D-printed dichroic goblet that looks brown when reflecting light and purple when light shines through it (9 March, p 12). Such effects have long been treasured. Some Victorians were obsessed by jewellery with dichroic “saphiret”, made by mixing molten gold and glass. Its production ended when gold got too costly, and is now sought after.
Great goblets of fire in several ages past (2)
The makers of the plastic goblet are a bit behind the curve. The colour of the 4th-century Roman glass “Lycurgus cup” shifts .
The editor writes:
鈥� The researchers do mention the Lycurgus cup in their paper (). They suggest that since only it and six other broken pieces found worldwide show the dichroic effect, this may have been due to serendipity rather than to mastery.
Spotting black leopards in Kenya in 1956
You published a photo of a black leopard in Kenya, saying it may be the only image of a fully wild black leopard in Africa in a century (23 February, p 28). I was a national service conscript posted to Kenya between 1954 and 1956. We became very familiar with all the local wildlife, sometimes more familiar than comfortable in the circumstances.
Early in 1956, I was one of a dozen squaddies who disturbed a pair of black leopards high in the Aberdare mountains. They made off quickly, but we were sure they were black leopards, not . That a military patrol could, by sheer accident, come across a pair of these animals seems to suggest sightings weren't too rare.
Another approach to milk production is possible
You report the idea of CRISPR gene editing to limit the number of unwanted male calves born to dairy cows (9 February, p 13). Surely it isn't beyond us to develop a breed of cattle that lactates without giving birth? I do accept that there may be ethical or moral issues with this proposal.
How to hack many cars at once and jam a city
You quote Simon Parkinson suggesting that a coordinated cyberattack on smart cars would take a lot of resources, so problems with such vehicles that result in gridlock may be more likely to result from a botched software update (9 March, p 8). But cars have a lot of hardware and software in common – for example . Flaws are likely to be present in models from different manufacturers.
A weakness that gave remote access to cars' on-board control networks could allow a person to disable many vehicles using only an internet-connected computer. Perhaps they could use satnav systems to select cars in a given area for maximum disruption.
It is Scotland's water, fatbergs or no
Kelly Oakes gives a fascinating and worrying account of fatbergs (26 January, p 22). But she claims that remedial action isn't easy because UK water companies are privately owned.
In England and they are. However, the water companies in and are public.
Papillomavirus is also involved in penile cancer
Jonathan R. Goodman's report on the causes of cancer is interesting and valuable (9 February, p 34). It mentions the link between human papillomavirus and cervical cancer – but not penile cancer, which . In Bali, penile carcinoma was in men in 2013. Male circumcision both cancers.
A share in the credit for stomach ulcer research
You report possible links between mouth bacteria and Alzheimer's, and note doctor Barry Marshall won a Nobel prize for linking Helicobacter pylori and stomach ulcers (2 February, p 6). initiated that idea, began the research and shared the prize.
For the record 鈥� 30 March 2019
鈥� A spacecraft that slingshots around Jupiter gains energy by slowing the planet in its orbit (16 March, p 10).
鈥� The SPF rating of standard sunscreen is primarily a measure of protection against UVB rays (16 March, p 28).
鈥� The “D眉sseldorf patient” seems to be cleared of reproducing HIV virus, though a few tests gave positive signals. These may be false positives, non-infectious virus fragments, or whole virus that couldn’t reproduce because of a lack of susceptible immune cells (9 March, p 12).