Letters archive

Our citizens' group has been tracking taser abuse across the US following the death of James Borden after tasering in our local jail on 6 November 2003. Our review of dozens of incidents reveals many cases where neither the officer nor the public were threatened. The taser has become the weapon of choice for bullying …

Readers may be interested in anthropological evidence for extremely subtle human interpretations of dogs' barks (12 June, p 52) . The highly mobile Native South Americans collectively known as Maku hunt extensively with dogs in the forests of the Upper Rio Negro and the Vaupes region of Colombia and Brazil. Their dogs signal the species …

You may be interested in my experience of the Aqua Detox machine (Feedback, 19 June) . I was seeing a physiotherapist, and she offered me a course of treatment with this new cure-all. One look at the leaflet triggered my fruitcake detector, so the opportunity to test it at first hand was irresistible. The machine …

Let's just suppose that the person operating the Aqua Detox device adds some unspecified salt to the water in the machine, as www.aquadetoxusa.com recommends. To get those "before and after" pictures, you need add nothing more exotic than common salt. An electric current passing through this salty water will make the electrodes rust, if they …

Colin Finch's theory on why CD jewel cases are so called is certainly imaginative and possibly even convincing, but sadly incorrect (19 June, p 31) . Jewel cases get their name from two small plastic bumps, or bearings, that the cover hinges on. The practice of using real jewels as bearings in watches and clocks …

Fred Pearce's article "Flame retardant shows up in Arctic" wrongly assumes that there is a lack of scientific data on the flame retardant deca-BDE (12 June, p 10) . It does not mention that after 10 years of scientific analysis and more than 100 studies, a scientific assessment by the European Union could find no …

John Griffiths explains clearly the benefits of cool-flame combustion (5 June, p 28) . But low-temperature combustion must decrease the Carnot efficiency. This theoretical maximum efficiency for converting heat into mechanical energy is determined solely by the temperature difference between heat source and sink. Typical combustion temperatures for an engine using cool-flame ignition may be …

It has been widely reported that a meteorite crashed through the roof of a house in New Zealand and rebounded off the sofa, making a second hole in the ceiling (19 June, p 12) . Wait a minute. This rock hurtled around space for 4.5 billion years, before heading towards Earth at around 50,000 kilometres …

If humanity is defined by an ability to love, empathise, feel guilt and embarrassment, and understand deception and cooperation (19 June, p 32) then dogs are human! I thought so (as do they).

The article on birds flocking refers to them "flying in one great and inexplicable mass" (26 June, p 48) . It seems to me that it has (since) been explained as emergent group behaviour built on very simple individual behaviour following these rules: 1. Keep together. 2. But not too close. 3. Follow the one …

Your article on the use of miniature internal combustion engines as power sources for portable electronic equipment leaves some questions unanswered (19 June, p 26) . For example: how do you prevent excessive wear over the lifetime of the power source? Most commonly used lubricants produce some exhaust residues and need to be delivered to …

I agree that software bloat is a pain (19 June, p 30) . In the good old days, I could twiddle a knob and see the radio tuning in. Now I just have to assume that the setting is optimal.