Causality casualty
Michael Brooks raises an important point about how we regard causality in his look at the paradoxes of a quantum universe (3 August, p 32).
快猫短视频s should not uncritically accept principles enunciated by philosophers, such as Immanuel Kant’s conception of the causality principle as a universal. This was never claimed by Kant’s contemporary David Hume, who viewed causality as a predisposition of the mind.
There is no reason to expect causality to be significant in the microworld of quantum mechanics. Those that disclaim this idea, as Einstein did, must provide evidence to the contrary.
Oxford, UK
Causality casualty
It is blindingly obvious what is happening with “entangled” photons 鈥� two photons produced by splitting a single photon using a half-silvered mirror 鈥� that seem to exchange information at superluminal speeds. In some extra dimension which we cannot see, the photons aren’t divided; they are still a single particle.
Swanage, Dorset, UK
Fighting depression
I am facing treatment-resistant depression myself, and being of a scientific mind, have already tried some of the new approaches you describe (27 July, p 34), including the drug ketamine. I hope to have repetitive transcranial magnetic stimulation (rTMS) soon.
Sadly, for me, large or small doses of ketamine bring only half a day or so of release. Unfortunately, it has also been experimentally confirmed that in the longer term, the drug impairs memory and multitasking ability, as I have noticed myself, and this is a heavy price to pay.
When I take what your article calls the “go-to tools for treating depression”, namely the SSRI drugs that boost serotonin, they produce the interesting effect of being supercharged on serotonin without altering mood. So I get the butterfly-stomach feelings and a floaty sensation, but with little to no emotional impact. For me, rTMS may be the only option left.
Montreal, Quebec, Canada
Product placement
In your feature on vagal nerve stimulation, HeartMath’s Inner Balance Sensor was described and, apparently, recommended (13 July, p 46). I bought it. Two weeks later, Feedback looked at the fruitloopy nature of an article by someone from HeartMath (27 July).
It seems disappointing that 快猫短视频 has become a pitchman for fruitloopery. Keep up your work against it, and remember that your readers expect your articles to be scientifically reliable.
Hellertown, Pennsylvania, US
The editor writes:鈥� We don’t endorse products, and are taking steps to ensure that in future, readers do not get the impression we are recommending products mentioned in articles. Feedback’s item was not about the sensor, although HeartMath is indeed behind that product. Of course, we hope it works.
Unhealthy stamp
Your look at whether modifying the US food stamps programme could combat obesity (newscientist.com/article/mg21929284.800) took me back to 1965, when I was a student in Philadelphia. My friends and I used to go to the federal building for free cornmeal, flour, oat flakes, red kidney beans, cooking oil, rice and other basic foodstuffs.
Then President Lyndon Johnson’s food stamps reached the city, and people were offered coupons redeemable in grocery stores. Those who had once collected wholesome foods now went to the supermarket and filled their trolleys with junk food. It was obvious that the new system would lead to unhealthier eating.
A better approach might be to subsidise basic commodities at the supermarket. It would cost little to administer and suffer little or no abuse.
Hastings, East Sussex, UK
Warning. Irony
I read Feedback’s item about the sign at a beach in Western Australia bearing the words “WARNING. Water” with interest (13 July). I too have seen the sign, and it left me speechless. Despite the fact that someone was killed by a shark a few months earlier at the same beach, I did not see a sign warning of sharks.
Canberra, ACT, Australia
Hydro claim holed
I question the International Energy Agency’s claim that there are “well-developed procedures” to ensure that major hydroelectric schemes are sustainable (6 July, p 6). Negative environmental and social impacts of large dams often outweigh the economic benefits.
Ensuring better management is hard in developing countries. An example is the poor use of environmental assessments and consultation during the ongoing building of the Xayaburi dam on the Mekong river in Laos.
However, small to medium-sized schemes do provide a way to manage the trade-offs between environmental, social and economic priorities.
Hanoi, Vietnam
Not so scary
David Flint is right to worry that the risk of methane from fracking leaking into the atmosphere may be underestimated (6 July, p 29). However, his estimate that a leak of 0.7 per cent of the methane in shale gas would cancel out any benefit to climate that fracking has over simply burning coal instead is a little low.
On a 20-year timescale, methane has 100 times the greenhouse gas impact of carbon dioxide weight-for-weight, but its impact per atom of carbon emitted into the atmosphere is only 36 times that of CO2.
What’s more, per carbon atom, the methane in shale gas produces about 65 per cent more electricity than does coal. Allowing for inefficiencies in burning coal, that stretches to 80 to 90 per cent, putting the break-even methane leakage at 1.3 per cent.
Sydney, Australia
Eyes on the prize
Eye disorders are proving excellent early targets for stem cell therapies, notably restoring damaged corneas and in clinical trials for age-related macular degeneration, as your report on the transplanting of lab-grown photoreceptor cells into the eyes of blind mice indicates (27 July, p 11).
The big challenge will be to transfer the three-dimensional cell-culture technique described in your article to people. Before human trials can start, the mouse model will require significant optimisation. However, there is no doubt that this work will significantly contribute to the fight against blindness.
London, UK
Stay tuned
In a relativistic look at the BBC’s Science Hour radio show, prompted by its 55-minute duration, you remarked that the listener “needs to keep re-tuning his radio, since the signal from the moving radio station would be shifted in frequency as well”. (Feedback, 20 July).
But if the transmitter moves at a constant rate, even 40 per cent of the speed of light as your reader suggested, then the Doppler shift is constant, and once tuned the radio should stay that way.
Williamstown, Massachusetts, US
Free to crash
Jeff Hecht’s look at distracted driving was very interesting (20 July, p 24). Here in Australia we have accepted laws to curb use of phones while driving, which will save many lives.
I cannot believe that parts of the US are so far behind in terms of legislation, but it makes some sense in the context of resistance there to the use of seat belts and crash helmets.
Adelaide, South Australia
Eco-mystical folly
The early days of Biosphere 2 demonstrate the folly of the more mystically inclined ecologists in seeing a purpose in evolution and geological history (27 July, p 41).
Why else, unless convinced that this planet has become the way it is in order for humans to live on it, would you build a self-contained system, intended to supply its inhabitants with sufficient oxygen, and put a “desert” in it? No wonder they started having breathing difficulties.
If we are not careful, “Biosphere 1” 鈥� Earth 鈥� may also fail to provide us with breathable air. Thinking that nature will provide for us regardless of our activities is dangerously mistaken.
London, UK
Second wind
Anil Ananthaswamy, in his discussion of shifting wind patterns on a warming Earth, points out that the margins of Hadley cells in the atmosphere of the mid-Cretaceous were at about latitude 27掳 “contrary to expectation” (20 July, p 34). Perhaps this is because an extra set of cells developed, so there were four in each hemisphere instead of the three we see today.
Liverpool, UK
Bomb the burp
So a giant “methane burp” as the Arctic warms could apparently worsen global warming and cost the world an estimated $60 trillion (27 July, p 16). The solution may not be rocket science… or maybe it is.
Surely the world’s superpowers now have the technical expertise to monitor this by satellite. And if it should occur, presumably they could quickly dispatch a missile to ignite the gas before it disperses. Admittedly, this would produce lots of carbon dioxide, but it has a lesser greenhouse effect than methane.
Newton Abbot, Devon, UK
Convincing accent
Tiffany O’Callaghan reports on the cultural cues our voices give (13 July, p 38). I testify in US federal courts as an expert witness on computer software issues and I have an English accent, having grown up in London and attended a private school in the UK.
I have been told that US jurors find my testimony more trustworthy because of my accent. I think that having an English accent in the US makes the speaker sound educated and intelligent, regardless of what is being said.
Portland, Oregan, US