Editor's pick – When I couldn't think without language
Max Starkey says he is bilingual and thinks in concepts and images, rather than either language (Letters, 7 December 2019). My experience is different.
When I came round in hospital after a stroke, I was relieved to be able to understand what had happened and what was said to me, and also to be able to consider what might come next. I busily made plans for my recuperation and tried hard to convince my husband that I still had my wits about me. Unfortunately, I couldn’t string together the words to explain this, despite knowing they were on the tip of my tongue.
Over the next few days, I came to a realisation. Although my thoughts were clear and even insightful, without access to a mental running commentary I couldn’t organise them into a narrative. They remained vivid, but individual, scenarios in my working memory, with the usual limitation on how many “items” can be held in this system at any one time.
Every time I tried to follow a line of thought, I realised after a few steps that I had forgotten where I started. This made me very aware of the importance of language in enabling us to manipulate our thoughts, as well as in communicating them to others.
Putting microplastics in proper proportion (1)
Textile fibres are a significant source of microplastic pollution, as Graham Lawton points out (7 December 2019, p 38). Beyond the many unknowns and confusions outlined in the article, textiles provide one more.
Humans have lived with textile fibres for millennia, and we are all familiar with the dust and lint that accumulate in our homes. Exposure to such particles shouldn’t come as a surprise.
Around a quarter of the fibres we use today are cotton, and a lot of the microfibre materials that appear in the environment are cellulosic, such as natural cotton and manufactured rayon.
One study found that about 80 per cent of microfibres in ocean sediment are cellulosic (). Surely these materials, too, are ingested and are capable of releasing dyes and chemicals used in their manufacture? Or are we giving “natural” materials a pass?
Putting microplastics in proper proportion (2)
Lawton mentions plastic particles smaller than a nanometre. As atomic diameters are about a tenth of a nanometre, a sub-nanometre lump should surely be a small molecule, not a polymer.
A complete solution to plastic pollution
You write that, as yet, plastic removed by Mr Trash Wheel from rivers flowing into Baltimore harbour can't be separated into reusables, so it is incinerated to generate electricity (14 December 2019, p 28). Recycling is fine, but it only postpones the day when the plastic starts to break down into smaller and smaller pieces. Incineration completes the life cycle of plastic from ancient sunshine energy to energy for present-day use, getting rid of the incinerated plastic completely. There are social problems, but these can be overcome by, for example, building incinerators far from housing.
The dynamics of a brewery in a gastrointestinal tract
I read with interest the case of a man who was intoxicated due to a gastrointestinal tract (GIT) infection with brewer’s yeast (Saccharomyces cerevisiae) (26 October 2019, p 14). The condition is thought to have arisen after prolonged antibiotic use, which would have decreased GIT bacterial flora and allowed an opportunistic infection with yeast.
What surprised me was that the yeast continued to be a problem long after the antibiotic treatment had stopped. Yeast is a eukaryotic organism and I imagined that its cell division couldn’t keep pace with that of prokaryotic GIT flora such as E. coli. Under anaerobic conditions, brewer’s yeast has a doubling time of 90 minutes. The doubling time of E. coli is around 20 minutes under laboratory conditions, but has been estimated at 12 to 24 hours in the GIT, much slower than yeast. The apparent rarity of this type of infection suggests that the biochemical characteristics of the yeast strain are significant.
How we nearly invented the internet in the UK
You mention the fundamental technology of packet switching being developed in the early 1960s by independent groups of researchers in the UK and the US (26 October 2019, p 34). Paul Baran's team at the US RAND Corporation came up with the idea of independently routed “message blocks”, while researching ideas for networks that could survive attack for the US Department of Defense. At the UK's National Physical Laboratory (NPL), Donald Davies's work was motivated by the increasing availability of powerful computers and the need to facilitate remote access. We were members of a small team at the NPL that worked on a proposal for a 12-node national network.
Davies first published his ideas in 1965. One of us, Roger Scantlebury, outlined the proposal at a conference in Gatlinburg, Tennessee, in 1967. Another paper presented there summarised the US plans for ARPANET, without defining its intended communications technology.
After discussions at the conference, packet switching was adopted for ARPANET, which debuted in October 1969. A preliminary version of the UK's first packet-switched network came into operation in January 1970 as a local network at the NPL.
In the UK, despite support from the IT industry, the government wouldn't fund a wide-area network. The Post Office, which then had a monopoly on communications infrastructure, believed speech traffic would always dominate data traffic and refused to sanction use of its trunk network.
All definitions of what constitutes life are false
Donna Lu reports on a search for unprecedented forms of life (16 November 2019, p 42). But how can we tell what is alive?
In Canada, there are frogs that freeze in winter and thaw out in spring. During dormancy, are they alive or dead? If living, they don't conform to any current definition of life. If dead, they shouldn't be able to revivify in spring. While frozen, they do nothing.
Or consider seeds that were dormant for thousands of years and then sprouted when cultivated. If they had done anything while dormant, they would have exhausted their store of energy and been unable to germinate. My conclusion is that it is impossible to distinguish life from non-life.
Power lines, big berries, birds and nutrients (1)
The many hypotheses as to why berries found under power lines may be larger and juicier than those elsewhere are fascinating (Letters, 23 November 2019). Looking out of the window at birds on a wire makes me wonder about waste products from birds falling under the cables, adding fertiliser and perhaps making the berries less appealing to animals.
Power lines, big berries, birds and nutrients (2)
Bird excrement contains nitrogen, potassium and phosphorus 鈥� all essential macronutrients for fruit production, as gardeners know.
Power lines, big berries, birds and nutrients (3)
While at school in the middle of last century, I remember learning that for deficient soils, power lines were a source of copper, which stimulated crop growth.
Near-death experiences and burials are a mystery (1)
You suggest that near-death experiences (NDEs) may be caused by lack of oxygen to the brain (23 November 2019, p 40). But this usually produces chaotic, hallucinatory experiences, confusion and memory loss.
NDEs are unlike this. They are serene, structured and well-integrated. It has been suggested they may be caused by psychedelic chemicals released by the body, such as or dimethyltryptamine. But there is little similarity between the experiences these produce and NDEs, and no evidence that they are released when a person is near death. NDEs remain a mystery, perhaps suggesting the view that consciousness is directly produced by the brain may be too simplistic.
Near-death experiences and burials are a mystery (2)
Archaeological evidence for afterlife beliefs goes back at least 12,000 years, when bodies started to be buried with useful stuff to take to the other side, says Graham Lawton. But there are other reasons to bury such items.
Those left behind may gain a feeling of closure by burying their loved one with things they cherished. Doing so may prevent the hurt they would feel on seeing someone else using those items.
Life with little sleep can be a mixed blessing
I was interested in your article about those who need very little sleep (26 October 2019, p 18). I am one such person and, at age 77, I would like to meet others. Some of my relatives and ancestors have or had the same ability.
In relationships, like attracts like. “Never sleepers” tend to have energy and stamina that others can find difficult to cope with. A “normal” child surrounded by those who need little sleep can feel very left out.
Among half a dozen of my relatives who need little sleep, I have observed shared traits of enthusiasm for endurance sports, ambidextrousness, some dyslexia, poor performance at school, high intelligence and an inability to sing in tune. I hope this is of interest. I would be pleased to assist any researchers who contact me through 快猫短视频.
More mammals that experience menopause
Humans aren’t the only land mammals to undergo menopause (9 November 2019, p 16). Adult female rhesus macaque monkeys (Macaca mulatta) of approximately 28 days. Those that live long enough experience menopause at some point between 24 and 29 years of age.
Carbon-dioxide-eating bacteria are no free lunch
Gege Li reports work to modify bacteria so they consume carbon dioxide instead of sugars (7 December 2019, p 19). This clearly requires energy: that would have to come from the sun or from chemical energy, and supplying the latter generally involves producing CO2. I would hope to see a more critical scientific assessment of the potential of such technology to remove CO2 from the atmosphere.
For the record 鈥� 11 January 2020
鈥� Brass is an alloy of copper and zinc, and bronze of copper and tin (14 December 2019, p 10).
鈥� A white dwarf star is made of atoms, and doesn’t collapse further because that would require their electrons to occupy the same energy levels, contrary to the rules of quantum physics (14 December 2019, p 15).
鈥� Cavitation consists of low-pressure bubbles forming in a fluid and then imploding (14 December 2019, p 16).
鈥� The flakes shedding from Jupiter’s Great Red Spot have an area of 100,000 km2 (30 November 2019, p 11).