Bulge science may change, but old difficulties remain (1)
So, as “Battle of the mid-life bulge” says, slowing metabolism is no longer a valid reason to explain broader girth among 45 to 65-year-olds (12 March, p 38). Hormones and lifestyles change, and the advice to sleep more and limit stress, where possible, is welcome.
But the what-to-do messages about expanding waistlines 鈥� mainly to eat less and also move more 鈥� are overfamiliar. The real challenge remains how to translate these much repeated themes into daily choices.
Bulge science may change, but old difficulties remain (2)
A study mentioned in the article found that between the age of 45 and 65, most of us put on 0.5 to 1 kilogram of body weight per year. This rate of gain corresponds to about 0.5 to 1 per cent more energy intake than expenditure.
Whether the overall increase in fat is due to increased energy intake, decreased expenditure or both can’t be determined because the imbalance is so small. In any event, this is a secondary consideration. We all know that we should sleep well, restrain our food intake and exercise.
Sea level threat is undoubtedly real (1)
Eric Kvaalen argues that scientists have exaggerated the impact of a 5-metre rise in sea levels, and says we can adapt over generations so a “massive refugee crisis” doesn’t transpire (Letters, 12 March).
I disagree. There is no exaggeration and the refugee crisis will be real, but it may remain hidden to many as more and more countries build impenetrable barriers to climate migration or adopt blanket exclusion policies.
We may already have a long covid drug test group
Michael Marshall mentions types of medication that have been identified as possibly protecting against long covid (26 February, p 38). These include aspirin and atorvastatin. I have been taking these daily for several years since having a heart attack and I believe they are routinely prescribed for this in the UK.
I caught covid-19 in January 2022, confirmed by testing. I don’t have long covid. Since there must be many people with heart conditions taking these drugs, I wonder if this could give us the opportunity to correlate the possible effectiveness of such medication against long covid.
Many flying creations don't even need a tail
You report research on the barn owl’s tail that could inform aircraft design (19 February, p 22). But whether efficient aircraft should have tails at all has been long debated. There are many examples of tailless aircraft and drones, plenty successful.
Ultimately, whether a flying machine or creature will benefit from a tail depends on what it will be doing up there. Soaring seagulls tuck their tails away when flying efficiently in still air, while few bats have found the need to evolve tails at all. On the other hand, the crow 鈥� and, it seems, the barn owl 鈥� can’t do without one.
We need to choose carbon capture species carefully
Your article on climate change mentioned some farmers in the UK replacing cereal crops with fast-growing Paulownia trees (19 February, p 20). This is a highly invasive species in the US that is already destroying native ecosystems there.
Although the prospect of a hardwood tree that can grow nearly 5 metres in a season seems tempting, it will be impossible to control. Each tree can produce 20 million seeds, which will be dispersed by the wind and will outcompete native trees. Paulownia is already banned in Connecticut and other US states may follow soon.
How to get the circular economy really spinning (1)
We can’t assume manufacturers will willingly get on board with a circular economy, given the temptation of planned obsolescence (12 February, p 38).
I had a flat-screen TV fail. The maker quoted 拢300 for a new circuit board, also suggesting I could replace the TV. On opening it (I have some competence in electronics), I found the cause: four capacitors had “blown”. I was able to repair the TV by replacing these at a cost of less than 拢1.
The capacitors had a rating about half of what it should have been for the circuit. It very much looks like this was deliberately planned and constructed to yield early failure to drive replacement or unnecessarily expensive repair. A functioning circular economy will need legislation to ensure that all stakeholders play fair.
How to get the circular economy really spinning (2)
The elephant in the room as far as waste goes is sewage. We produce huge amounts of it and it creates methane as it decomposes. In large sewage works, the methane is used to power machinery and to mix material by bubbling it up through new sewage.
If surplus methane were sold and injected into the gas supply system, this would achieve circularity. Perhaps we could also decompose grass and other vegetation in anaerobic digesters to create sufficient methane to carry on using our gas boilers 鈥� much better than scrapping them and installing costly heat pumps.
How to get the circular economy really spinning (3)
Recent articles and letters have highlighted the importance of “waste not, want not” to reduce our environmental impact. Even more powerful is an approach we might call “want not, waste not”: by reducing our desire for ephemeral or short-lived possessions for which we have no real need, we can have an even greater effect.
Such a philosophy has deep roots in society, including the
Not theirs as such, but certainly adopted by them… Quaker adage to “live simply, so that others may simply live”, and William Morris’s famous aphorism: “Have nothing in your houses that you do not know to be useful or believe to be beautiful.”
How to get the circular economy really spinning (4)
While agreeing that equipment should be longer-lived and repairable, I suggest that your readers who wanted a new spice and nut grinder (Letters, 26 February) invest in a pestle and mortar for the spices and a strong knife and chopping board for the nuts. Good quality versions will last a lifetime and require no electricity.