site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com Thread-index: AcaP96CO3tqiIvvqEdqRwwAKlZmxFg== Thread-topic: cpufrequency User-agent: Microsoft-Entourage/11.2.4.060510 On 14/6/06 20:48, Dirk Schelfhout wrote:

On 14 Jun 2006, at 21:23, Howard Oakley wrote: I don't want , or need a health discussion. I just wanted some technical help. If you want to discuss this with me further off-list, feel free to do so.

Dirk, Please take care when quoting so that you do not misquote as you did above: *you* wrote those words, not I. And I happen to be providing you with technical help, as I happen to be a medical practitioner who (among other things) works with RF and has had responsibility for medical RF safety. I have also followed the published research and various speculative reports that have appeared. Now read the following very carefully, please: 1. The only consistently reported biological effect of exposure to non-ionising radiation of any significance is of heating. There have been reports of effects on cell division, but for the sort of exposures that you are talking about, those are both marginal in likelihood, and not relevant to a complaint of headaches. 2. Tissue heating, particularly if asymmetric, can be supposed as a potential cause of headaches, because of its effect on blood flow (when tissues are heated, you get local dilation of blood vessels, which increases local blood flow). 3. Some studies have suggested that holding mobile phones against the head *when connected and thus transmitting* can have small local heating effects as a result of absorbed RF energy. The effects are normally small, but have provided a possible mechanism for headaches and other effects caused by RF. However, most mobile phone users do other things, such as talking (which causes hyperventilation, and more) that are well known to cause headaches, and dissociating those effects has proved hard. 4. In order to get close to the absorbed energies that equate to those from transmitting mobile phones, from your processor, etc., you would have to have your head very close to the keyboard (and even then I don't think that you could match them), which would make reading the screen so awkward that that would be far more disturbing than any RF involved. Indeed, if there is any RF issue with laptops, it is more likely to arise from the purpose-made transmitters - WiFi and Bluetooth - that most now include. The easy solution for them is to turn them off, of course. Indeed, if you want to try an experiment, get a friend to set a laptop up in a room, with wireless communications running and active, then cover the laptop with a thin sheet so that you cannot tell whether it is transmitting. Time how long it takes you to get a headache. Then leave, and get them to repeat with wireless turned off. Tell them to do this a few times in 'random' order, and see whether your headaches statistically develop more frequently when the wireless comms are active. It is essential that you are 'blinded' as to whether wireless is active, or you could subconsciously influence the result. 5. Human beings are not Cartesian dolls, and we are always stumbling across exceptions. Maybe someone can navigate the globe using an inbuilt biological GPS - I cannot disprove it. But in medicine, common things occur most commonly: if you *or anyone* has headaches when using a computer, you should rule out the common and well-understood causes of headaches before concluding that the cause is RF. The correct way of doing that is not by trying to apply engineering logic to the body, but by obtaining proper specialist help and assessment. A very very small number of persistent headaches, for example, result from brain tumours. Wouldn't you want to know with reasonable confidence that you were not developing such a tumour?

I am not unique, do some research.

Everyone is unique, and I have researched this, and keep a careful watch on the literature. If you feel that you have scientific evidence to the contrary, I greatly welcome the references to the original papers, please. I am sorry to dwell on this OT matter, but as it concerns health, safety, and popular speculative issues, I think it has more general relevance until the listmom stamps on me! Howard. Dr Howard Oakley The Works columnist for MacUser magazine (UK) http://www.macuser.co.uk/ http://www.howardoakley.com/ _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... This email sent to site_archiver@lists.apple.com