Why the brain seems to be like a fighter jet
While reading your article on the potentially unstable brain, I was reminded of a close parallel: controlling the Eurofighter Typhoon, a modern jet fighter. In essence, the plane is aerodynamically unstable and requires computer input to function. However, the gain is that the plane is more manoeuvrable and more agile. The key point is that there is no preferred state that would tend to oppose a change of speed or direction. The same might well be true of the brain: balanced on the edge of criticality, without a preferred state, it can respond rapidly to any challenge(6 September, p 30).
Other causes of the French revolution
While volcanic activity and related crop decline may have been a factor, multiple causes led to the French revolution, such as the high-spending habits of the French aristocracy and the cost of France’s support for the American revolutionary war of 1775-83. This itself was the culmination of several years of repressive British taxation of American colonists. Perhaps if Britain had been more conciliatory to the Americans, France might have peacefully liberalised, with no revolution(6 September, p 11).
Public transport: the debate continues (1)
Regarding whether public transport will solve all our travel woes, there is a solution waiting in the wings, in the form of autonomous taxis. A driverless taxi that you hail through an app solves the disadvantages of public transport and might even be cheaper, once you account for the lack of personnel costs(Letters, 6 September).
Public transport: the debate continues (2)
I totally disagree with Rosemary Sharples on the issue of public transport woes. I grew up in Hong Kong, where only about 10 per cent of the population own a car. I could certainly choose the route and time when travelling on public transport, except during the wee hours. Hong Kong has an excellent subway train system that doesn’t have traffic jams and carries about 5 million passengers daily out of a population of about 7.5 million. After emigrating to Australia, I observe one thing: suburbs with bigger car parks also have more overweight residents. I believe low car ownership is a blessing, and indeed Hong Kong as of this year has the longest life expectancy of any country.
Please sign me up for high-tech specs
Having been a wearer of varifocal glasses for several years, I was heartened by the Taiwanese research using liquid crystals to dynamically switch between near and far visual modes(13 September, p 15).
The nice thing with conventional bi/varifocal glasses is that one quickly learns to make the necessary head movements to bring the appropriate part of the lens over the object of interest. To match this, liquid crystal or fluid-filled active optics would have to switch very quickly, smoothly and, most importantly, automatically as one attempts to focus on different objects. This would require an eye-tracking element and a rangefinder, further increasing the cost and weight. But if this could be perfected at a low enough cost, it would be a huge boon to many people.
A history lesson for those who want to ditch infinity
The “ultrafinitists” who seek to abolish the use of infinity in mathematics reminded me of the influential Dutch mathematician L. E. J. Brouwer, renowned for proving Brouwer’s fixed-point theorem. He went on to found an approach to mathematics that he called intuitionism, which included a rejection of the concept of actual infinity, though it admitted the idea of potential infinity. Intuitionism has since fallen into obscurity(9 August, p 28). Could the ultrafinitists be reinventing work of the past?
Welcome new approach to taming cancer (1)
I like the sound of treatments where cancer cells are re-educated, so that they revert to behaving like normal cells. I wonder if it would be worth seeing whether a similar method could be used with malfunctioning connections between nerve cells, in the brains of people with Alzheimer’s, to encourage them to be repaired(30 August, p 40).
Welcome new approach to taming cancer (2)
As your dispatch rightly stated, chemically converting cancer cells to benign ones mimics the process of embryogenic differentiation in which myriad cell divisions, beginning with the fertilised egg, yield populations of newly specialised cells with curtailed growth rates. Those cells form our tissues and organs. This is, in fact, an “epigenetic” process in which external chemical signals in the environment control which genes are expressed or repressed.
Because cancer is actually a heterogeneous family of malignancies, identifying these in vivo epigenetic signals has proved to be a daunting task. Paediatric tumours, however, present the greatest chance of success, since they may well be the earliest consequence of embryos that failed to encounter their epigenetic signals.
Is print or digital best while on the toilet? (1)
You report research that says smartphone use on the toilet may increase the risk of haemorrhoids by nearly 50 per cent. That leaves me to assume, or at least hope, that crosswords and printed magazines are more benign(13 September, p 10).
Is print or digital best while on the toilet? (2)
With reference to your article “Smartphone use on the toilet may raise risk of haemorrhoids”, I am left wondering whether reading the print version of 快猫短视频 on the toilet carries the same risk? Or is it only if I read it via the app on a smartphone? More research is required!
For the record
During the Little Ice Age, temperatures dropped by an average of up to 1.75掳C, or 3.15掳F (6 September, p 11).
The term atrox is a Latin word meaning fierce (6 September, p 14).