Thursday, April 10, 2008

MIT open courses

Nobody could have missed that I love to listen to audio and video lectures on my spare time. In particular when I am doing something where I do not have to concentrate (such as doing dishes or walking the dog). I recently wrote about The Teaching Company which is probably my favorite company in the world. I have also mentioned Berkeley webcast and in particular the lecture series called physics for future presidents taught by professor Richard A Muller.

When reading Lunkens blog I saw some really good news. MIT, one of the most prominent Universities in the world (particularly in physics, technology, and computer science), have been inspired by Berkeley and have now made a good deal of their courses available online for free, hurray for that! For example, here is a lecture series on introductory biology taught by Eric Lander (see picture above), a key figure in the human genome project.

So, make use of these fantastic resources. With a few clicks on your mouse you can enrich your life by learning about anything you wish from world leading experts, who are also in my experience fantastic teachers.

Saturday, April 5, 2008

Dangers of radiation in the home

The best Swedish site for news on technology, in my opinion, is Today they have an article on radiation in the home. The article is based on an interview with Maria Feychting professor in epidemiology at Karolinska Institutet. The article discusses the danger of the radiation associated with products that are becomming increasingly common in ordinary homes. I am speaking of mobile phones, routers, wireless keyboards and mice, bluetooth headsets and dect phones.

The conclusion of the article, briefly put, is that there are no scientific evidence that this radiation causes any harm. It is a fact that studies showing potential dangers of radiation get much more attention than studies which show zero effects, even though the latter type are much more common. Furthermore, most of the studies which have shown slight biological effects of radiation have subsequently been replicated with contrasting results i.e. the latter studies did not find any effects.

I think that one of the reasons why some people are so afraid of these things is the fact that they radiate, and we all know that radiation is bad right? No, not necessarily so. Radiation can be your friend to. If it were not for the radiation from the sun we would not be alive. Similarly, seeing involves the capture of radiation by photoreceptors in the back of your retina. In fact we are all rich sources of radiation which you can see for yourself if you have a camera that pick up infrared wavelength.

But isn't that different? Sure some sorts of radiation are more dangerous than others. Cosmic rays which arive from outer space are extremely rich in energy, and alot of that type of radiation would be bad for you. Similarly, X-rays will slightly increase the risk of cancers because it is rich in energy. But what about the radiation from all those home devices? This radiation is lower in energy than normal visual light, so you are very unlikely to get cancer from this type of radiation. These devices actually emit microwaves, just like your microwave oven. The difference is that the radiation is not contained within a box, and also the power is 10,000 smaller than in an ordinary microwave oven (for a dect phone it is 100,000 times smaller). If you want a different point of view on these issues, you can visit this page.

The article also gives some quick answers to the following questions:

1. Does radiation from mobile phones cause cancer: False

2. Will using a bluetooth headset reduce the amount of radiation you are exposed to: True (because a bluetooth headset has a much lower effect than the mobile phone)

3. A dect phone emits more radiation than a mobile phone: False

4. A 3G phone radiates more than a GSM mobile phone: False

5. More wireless devices in the home will make it more dangerous: False

6. A new router radiates more than an old router: False

7. It is dangerous to have your mobile lying next to you when you are sleeping: False

8. The mobile will emit less radiation if you hold your hand over it: False (actually it will radiate more becuase that is necessary in order to communicate the station.

9. Even the good old cable hardware emits radiation: True (anything with a current in it, a cable for instance, will generate a magnetic field which is also basically a form of radiation.

I want to end with a personal reflection on an issue which I think is highly relevant yet often forgotten. Mobile phones, which as mentioned is the device which has the highest effect and thus the highest radiation, has been around for about two decades now. In spite of their popularity, there has not been any increase in cancers in this timeperiod. This "natural experiment" shows that if mobile phones have any effect at all on the human body, that effect have to be very subtle. Pretend for a moment that there has been a slight increase in some obscure form of cancer, or other type of disease, that is a result of mobile phone radiation. Even such a necessarily slight effect would pale in comparison to the enourmous benefits of being able to call ambulances, fire fighters and the police from almost anywhere on this planet. Hurray for mobile phones!