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Debunking a YouTube hit
I would like to really thank you for the precise and clear job you've done to counter the manipulation of the "muslim demographic" video. The video has been seen 10 million times on You Tube . But when you perform a search on the google video engine, the video is in fact replicated on many sites. Unfortunately, on the google video search, "muslim demographic : the truth" only comes up today on page 3. As we all know, very few internet users will reach that page...I will personally share your video with a large extent of my contacts. Let's hope the "more or less" video can soon come on page 1 in internet search engines. Vincent Placer, France
For a video which isn't even able to correctly quote the number of EU member states, is it really a surprise that the rest of the mindless propaganda is wholly inaccurate? Peter Mayne
I agreed wholeheartedly with your piece yesterday about the wild claims of some regarding the Islamification of the UK and I applaud your bravery in dealing with the otherwise taboo subject. Whilst I agreed with your debunking of some absurd assumptions there were also some assumptions in your own case that might be questioned. The idea that migrating populations adopt fertility patterns of hosting populations is not universal. Where religious groups are concerned it is in fact clear that they carry with them their traditional fertility patterns. As an example, the Catholic pattern is very similar the world over and does not tend to the norm of any containing population. Where a migrating group is closely knit by language, faith culture etc. the tendency is to remain separate and not to trend towards the norm in any medium term timescale. Paul J. Weighell
The Pythagorean comma
You told the story of Pythagoras passing a smithy and hearing the different pitches from the different hammers and anvils, in nice integer ratios. It's a nice story, but anyone who has wielded a hammer in this way will recognise that it is just a story. There is no simple relationship between the size of a solid object and the nominal pitch it produces when struck. As well, the overtones are almost guaranteed to be markedly non-integer multiples of the fundamental frequency. Pythagoras would have gained no insight into the numerical relationships between the tones from looking at the sizes or weights of the hammers or anvils. As an example, bell makers have go to some considerable lengths to design a shape for the bell which has approximately integer ratios for the first few overtones at least. This has to be worked at - it is certainly not a self evident consequence of the bell's shape. Scott Campbell, New Zealand
Having long considered mathematics merely a convenient human construct capable of proving/disproving virtually any concept, particularly when used to formulate statistics, today's programme went some way to confirming this regarding suspect musical notation, where the object appears to count the notes accurately rather than sitting back and enjoying a performance, wrong notes and all, indicating that mathematicians should get out more. Gordon Petherbridge
I would like to congratulate you on your excellent report on numbers and music in relation to keyboard instruments. I was waiting with baited breath for the usual misconceptions to be trotted out and they weren't. You didn't even repeat that oft quoted misconception that Bach composed his 40 Preludes and Fugues to demonstrate equal temperament. John Pike Mander
DNA to stay?
The item about the misuse of statistics by the police, in their attempts to justify retention of the DNA of innocent people was more about the misuse of language than the misuse of statistics: confusing "rearrest" and "reoffending," for example, or by assuming arrest means guilt. This is a confusion of definition which then seems to lead to the statistical conclusion the police seem to want. I have no idea whether this is deliberate on their part, but it certainly isn't a problem of their misinterpretation of statistics, just of their native language! Sara Neill
In all the discussions regarding the police DNA data base including yours, just now, the tacit assumption seems to be made that anyone not convicted is therefore innocent. Wrong wrong wrong! All you can say is that the evidence produced has not convinced the public prosecutor or the jury. Clearly an important part of gathering evidence for a re-trial will be the DNA file. To my mind, therefore, there is no motive for ceasing to hold this evidence (under proper control) and every motive to do so. The statistics of reconviction do not affect this argument. The statistics of re-arrest may well be more relevant where the arrested is skilled at concealing evidence. Paul Cope
What are the odds of an incorrect match occuring on the database in someone's life time? Each year younger and younger people are put on the database so that someone may well be on it for over 65 years. Now knowing how many times the database is searched each year proivides a start for estimating the answer to this question. However it is important also to take account of the fact in the future as DNA detection becomes easier and cheaper more and more searches will be done (perhaps in 50 years in may increase 50 or 100 or even 1000 fold as DNA replaces figure printing etc.). Mr M Watkins