Could poor sleep be behind many cases of dementia?
From Andreas Keller
Hannover, Germany
After reading that inhaling high doses of carbon dioxide in a controlled setting clears Alzheimer’s proteins from the brain, two questions occurred to me. Firstly, might some cases of dementia be a result of years of interrupted sleep? The way work is organised in most societies means that many people regularly interrupt the natural sleep process by using an alarm clock (1 August, p 4). If deep sleep involves a clean-up process, including for those “garbage” substances whose accumulation might have something to do with neurodegenerative conditions, could this be a contributing factor in people who might, for some reason, be prone to producing more of such substances than others?
Secondly, after an occasional night of bad sleep, I not only feel tired the next day, but also slightly emotionally imbalanced. Could the accumulation of substances cleared out by deep sleep (and perhaps also by the therapy described in the article) lead to emotional problems like depressions or anxiety?
The complex economics of new battery technologies
From Philip Jessops
Marloes, Pembrokeshire, UK
All improvements to batteries, including the salt variety, are welcome. However, domestic batteries can fully benefit a country’s grid, maximise renewable electricity use and, most importantly, address energy poverty only when there is high market penetration. Low-income households, which might gain the most, probably can’t afford batteries. And if they got one through a subsidy scheme and it failed, as some do, they may have no cash for repair or replacement (18 July, p 15).
The solution: householders don’t buy batteries. Utilities or grid operators that can bulk buy them cheaply should rent batteries to all, with no-quibble support and constant performance monitoring. This way, households aren’t affected by technology changes or suppliers going bankrupt. As new battery designs come along, they will get an upgrade, with the old equipment properly recycled. And should circumstances change 鈥� they have a heat pump or solar panels installed, say 鈥� there could be a fee increase to cover either a bigger battery or an extra one.
We need new business models as well as better technologies.
From John Kitchen
Kettering, Northamptonshire, UK
Your article, which mentions that salt batteries could be used in budget electric vehicles (EVs), underestimates the importance of the second-hand market for EVs. People on lower incomes tend to buy second-hand cars, and they are less likely to have driveways on which to charge an EV.
Why I quit my research on hissing cockroaches
From Margaret Cuthbert
Ithaca, New York, US
Anthony Spiteri’s letter on the ethics of insect experiments makes the strong point that we are often able to ignore potential suffering where the subject is unable to communicate with us. I was fortunate to spend many years researching the communicative behaviour of the Madagascar hissing cockroach ( Gromphadorhina portentosa ) and its neural basis. It was the nearly unique ability of these creatures to communicate in a modality that we easily relate to (sound) that led me to years of research, but that ultimately caused me to leave this work behind (Letters, 18 July).
Insects are often anaesthetised with carbon dioxide when being used for research involving dissection, as was necessary for my work. But as this wore off, my experimental cockroaches, pinned down, would begin to express their distress vocally by hissing. Had I been working with other invertebrates, there would have been no evidence of my impact, but not here. Ultimately, I knew that I was hurting my study subjects, and I couldn’t condone my own actions when I had such clear evidence before me.
Another benefit of getting the sun all over your body
From Sam Edge
Ringwood, Hampshire, UK
Naturists would probably agree with the conclusions in Rowan Jacobsen’s book In Defense of Sunlight . Not only does getting safe amounts of sunlight on more of your skin seem to improve health, when done among strangers, it also promotes a more accepting attitude towards your own and others’ bodies, and any perceived imperfections they may have (25 July, p 24).
My partner and I rarely find opportunities to indulge in this practice in the UK, for lack of clement weather and suitable locations. But after a few holidays in Denmark, Germany and Gran Canaria, where there are many nudist beaches, we finally got up the courage to discard our bathing clothes and enjoy the sun, sea and sand of Spain’s Maspalomas dunes au naturel with our distinctly “less than perfect” older bodies. It was very freeing!
The advertising industry is fuelling overconsumption
From Merlin Reader
London, UK
One issue not covered in your article on the green transition of Guimares, Portugal, is useless, consumptive kinds of “economic activity”. The advertising industry, specifically, uses enormous resources to encourage consumption, with the small exceptions of charitable advertising (though we wouldn’t need charities if wealth was more equally distributed) and public-service advertising (advising us to take care near water in heatwaves, for example). Yet, advertising still counts as economic activity (18 July, p 32).
I recently saw a pundit on TV complaining about the lack of economic growth in the UK. The interviewer failed to question why non-stop growth is necessary, or point out that it isn’t possible on a finite planet. Those of us in western Europe are already in a society overconsuming at an unsustainable rate.
Hot baths may be helping me stave off ill health
From Nasir Ali
Inverness, UK
Regarding your article on heat therapy, since 2001 I have been taking a daily hot bath, lasting 90 minutes. Since I started this regime, I haven’t had a serious cold, flu or covid-19, and my Lyme disease symptoms have gradually disappeared (18 July, p 26). Might my hot baths be affecting my immune system?
For the record
Kurt G枚del鈥檚 incompleteness theorem showed we can鈥檛 ever prove that mathematics could be fully consistent (25 July, p 18).
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