Currently I’m working on some simulations and it strikes me as rather difficult to obtain a generally “realistic” model, despite most of it being quite easy to understand.

The system in question is a series of interacting magnetic particles. The basic ingredients are all there; a couple of terms that favor alignment of like spins near by, a term that favors opposite alignment for spins far away, a term to control the external applied field and a few different schemes for introducing disorder, changing the spins, and such. All in all, it’s not too difficult to understand and even to get it into a computer program that does the basics.

Along the way you may encounter a few difficulties if you’re new at writing numerical models (such as how to account for boundaries in your simulation, or how to solve various equations and in which order to do them). But with some practice and a decent library built up over time (or through the use of other people’s libraries) you can have the basic thing going.

What strikes me as hard at the moment is settling on an area of “parameter space” for which the model can describe what we’ve seen experimentally. Ideally what I’d like is the following: to find a set of parameters such that I only need to vary one of them to properly describe things. Now, I’ve got 3 different parameters (well, 4 actually, but I’m forcing one of them to be equal to 1 since I can divide all the other parameters by it). Two of those parameters I think I can link together by a particular relationship and then only have to vary one of them. However, right now everything seems very, very “touchy.” Small adjustments in even one of the 3 parameters can take it from describing things pretty well to looking very meaningless.

More good news of late :

We appear to be headed towards a real, positive change in our nation’s (and hence hopefully the world’s) nuclear weapons policy. I think too many of us assume that this threat somehow vanished with the end of the cold war. Many of my students have not even lived in that era and seem to find the whole matter somewhat unbelievable. And I suppose that’s a matter of great concern as these weapons and devices still very much exist, and are still very much ready to be used in very short order.

Aside from utter global annihilation, we also live with perhaps a much more real threat today from small groups/terrorists that could perhaps obtain such a weapon. While large nation states may be seen to be somewhat reliable (or at least readable), small groups with no concern for their personal welfare pose a significant threat. I think few young people today really understand the nature of these devices and what incredible devastation can be brought by even a single detonation. It’s sort of the modern “Base Commander Ripper” from Dr. Strangelove.

Anyhow, I am encouraged that we seem to be moving towards not only fewer devices, but hopefully better control over those we do possess.

Great news, Simon Singh has won his appeal of a lawsuit brought by a chiropratic organization in England for his (well founded) criticism of some of their beneficial health claims. Despite having a great deal of evidence based medicine (you know, actual science!), the libel laws in Britain allow science writers (and others) to be sued in sort of an “guilty until you prove you’re innocent” fashion. The effect has been a sustained choking of anyone writing critical statements of various fringe, cult, pseudo-science, etc groups/people.

Anyhow, it appears that this is a very positive step.



----- From Sile Lang, Sense About Science -----
 
Dear friends
A very quick note to make sure you heard that Simon Singh’s appeal in his case with the BCA was upheld today. It means that Simon can now defend his article as comment rather than as fact, as Justice Eady had originally ruled.
Simon said today: “It is ridiculous that it has cost £200,000 to establish the meaning of a handful of words. I am delighted that my meaning has been vindicated by three of the most powerful judges in the country, and I relish the opportunity to defend this meaning in court. However, I am still angry that libel is so horrendously expensive. That is just one of the reasons why the battle for libel reform must continue.”
You can read more comments from campaigners and supporters at www.libelreform.org/news/450-judgement-in-simon-singh-libel-case
And the judgment and Simon’s lawyer’s notes on what this means for Simon’s case and for libel reform is here: http://www.senseaboutscience.org.uk/index.php/site/project/473/
Jack of Kent has blogged on the ruling here: http://jackofkent.blogspot.com/
The Guardianhttp://www.guardian.co.uk/uk/2010/apr/01/simon-singh-wins-libel-court
The Daily Telegraphhttp://www.telegraph.co.uk/news/uknews/7543685/Science-writer-Simon-Singh-wins-Court-of-Appeal-libel-battle.html
BBC Radio 4 World at One http://www.bbc.co.uk/programmes/b00rlff7
BBC online http://news.bbc.co.uk/1/hi/uk/8598472.stm
And check here for updated lists of press coverage: www.senseaboutscience.org.uk/index.php/site/project/473/
Keep an eye out for Simon, his lawyer Robert Dougans and members of the libel reform campaign on Channel 4 news, the BBC News channel, Sky News and BBC radio stations this evening.
Simon, and the campaign for libel reform, both still have a very long fight ahead of us. We are very pleased  the three most powerful members of the Judiciary in England have recognised  the need for libel law reform. We need to make sure everyone else does too.
Best
Sile