Monday, 29 October 2012


All right.  Let's do this.

Way, way back in March, I talked about Roguelikes in general, and gave my opinion of one of the main examples of that genre of game, Angband.  I followed this up with a review of probably the most famous example, NetHack, in April.  I originally intended to these reviews a regular series, and planned to review another major variant, Crawl, a week or two later.

Well, only six months late.

Thursday, 25 October 2012

Who the Hell is Mallory?

Via the BBC, worrying news for Android users like me:
Our analysis revealed that 1,074 (8.0%) of the apps examined contain SSL/TLS code
that is potentially vulnerable to MITM [Man in the Middle] attacks. Various forms of SSL/TLS misuse were discovered during a further manual audit of 100 selected apps that allowed us to successfully launch MITM attacks against 41 apps and gather a large variety of sensitive data.
Now, I don't use my Android phone for anything sensitive.  Further, the Android marketplace is open, so you'll have good and bad software there; in that sense there's no surprise that some of the apps have security flaws.  I've only skimmed the relevant paper, but I didn't see any list of who these troublesome programs were from.  The authors do observe that the insecure apps include mainstream ones, with tens of millions of installations, but at first glance this seems to be what you'd expect in an unmonitored market.  In short, caveat emptor and be careful with your data.

What I found most confusing, though, was the title of the paper: "Why Eve and Mallory Love Android".  Eve of course is the common name for the eavesdropper in cryptographical circles, but I've never heard of Mallory, hence my question above!  Some wiki-ing gives the answer (the malicious attacker) and a long list of names that makes it clear I know much less about cryptography than I though...

See Ceefax No More

So I find to my surprise that Ceefax has been officially turned off:
BBC Ceefax, the world's first teletext service, has completed its final broadcast after 38 years on air.
Ceefax was launched on 23 September 1974 to give BBC viewers the chance to check the latest news headlines, sports scores, weather forecast or TV listings - in a pre-internet era where the only alternative was to wait for the next TV or radio bulletin to be aired. 
I say surprising not least because I wasn't aware it was still running.  Indeed, during my entire time as a student (under- and postgrad) I never owned a TV and rarely watched one, and I pretty much forgot the whole concept of teletext existed.  I guess it's like returning home and finding that one of the playgrounds of your youth that'd faded from your mind was torn down and rebuilt; makes you feel old.

Tuesday, 23 October 2012

Because Predictions are Never Wrong

Ominous news from Italy:
Six Italian scientists and an ex-government official have been sentenced to six years in prison over the 2009 deadly earthquake in L'Aquila.
A regional court found them guilty of multiple manslaughter.
Prosecutors said the defendants gave a falsely reassuring statement before the quake, while the defence maintained there was no way to predict major quakes.
It is important that the government, including government scientists, should be held accountable.  But the case here is not good.  The prediction of earthquakes is an inexact science; with current knowledge, we will always make mistakes.  And yet that seems to be all these people have been found to have done, made an error.

Monday, 22 October 2012

Three is a Large Number

One thing I sometimes like to joke is that in  physics, there are only three numbers: zero, one and infinity.  By that I mean that you can get a decent rough estimate in many cases by treating the relevant parameters as one of those three values.  The entire field of dimensional analysis involves setting numbers to be one in the appropriate units; for example, consider atomic physics.  We are in the quantum regime, so we need Planck's constant h; the dominant force is electromagnetism, so we'll need the vacuum permittivity ε0; and the electrons form the "outside" of an atom, so let's also consider the electron charge e and mass me.  There's only one way to combine these objects to have the dimensions of energy:
$\frac{m_e e^4}{\epsilon_0^2 h^2}$
Up to an overall constant, this is the Rydberg, which indeed characterises the energies of atomic physics, and which is normally derived after several weeks of quantum mechanics.

Setting things to be zero is fairly intuitive.  Small things normally have small effects, and can be ignored at first.  Correcting for them being non-zero is then precisely a perturbation series.  Interestingly, setting numbers to infinity is pretty similar; there are plenty of situations where the mathematics can be exactly solved when a coupling g goes to infinty, and then corrections come as a series in inverse powers of g.  A somewhat different example is in the strong interaction, which has three colours (analogous to the single electric charge).  Before I was born, Dutch physicist Gerard 't Hooft was able to successfully analyse the strong interaction by setting the number of colours to be infinity.  Despite three not being very big, the approximation was successful.

In a similar vein, we have the paper I want to discuss today.  Like 't Hooft, Bai and Torroba are approximating a number that equals three by infinity.  Instead of gauge interactions and colour, they have chosen to look at flavour and the number of generations.

Friday, 19 October 2012

Homophobia in England

Apparently, the far right are a bunch of bigots.  Shocking, I know.
Police in Cambridgeshire have said they are investigating complaints made after the leader of the far-right British National party, Nick Griffin, posted the address of a gay couple on the internet and appeared to urge his supporters to demonstrate outside their home.
This relates to a recent case that was actually quite pleasant and uplifting.  An elderly gay couple tried to stay in a bed and breakfast, but the owner refused to let them share a bed.  They sued and won, which shows that the British courts do get things right sometimes.

Of course, to the BNP demanding you are treat fairly is "bullying" if you're not a straight white English man.  Posting someone's address online and asking your followers to harass them is not, though.  We even got an accusation of "heterophobia", which I think completes the bigot bingo.  Still, one thing did make me laugh; after it emerged that Griffin might face criminal prosecution for his acts, he immediately started whining:
Griffin then wrote: "Why don't left & gay activists confront Muslims instead of picking on meek & forgiving Christians? Bullies are always cowards!"
That last line is just precious, given that Griffin has now exhibited both behaviours—bullying and cowardly whining—in this single incident.

Lines and Boxes in the Sky

I've talked recently about the potential signal of dark matter found from gamma ray photons with an energy of 130 GeV.  One paper from a several weeks ago that I've wanted to discuss made a simple but interesting point.  You see, the most obvious interpretation of this signal is from dark matter self annihilating directly to a pair of photons.  This direct production gives us a mono-energetic spectrum.  But instead of a line, we might have a really narrow box, coming from a two-step process.  And this is actually quite natural in certain types of models.

To go into more detail, we'll need to cover some basic kinematics.

Thursday, 11 October 2012

Gay Rights in Ukraine

Courtesy of the BBC, it looks like LGBT rights are in danger in Ukraine:
The Ukrainian parliament could give final approval next week to a bill that aims to outlaw "pro-homosexual propaganda" - any "positive depiction" of gay people, gay pride marches, or even the screening of a film like Brokeback Mountain.
The story is a depressing parade of the usual, such as this guy:
Supporters of the bill, like Ruslan Kukharchuk, a founder of the local group Love Against Homosexuality, deny the accusation of intolerance. They say they too condemn the violence against homosexuals. What is more, they add, gays are free to do whatever they want "in the privacy of their room".
Kukharchuk, however, has also written about what he calls the "homo-dictatorship" which he claims dominates Western society and persecutes religious, anti-gay proponents like himself. He strives to counter "aggressive" gay propaganda, he says - in other words, public discourse that implies that homosexuality "is normal, is good, is part of democracy".
 Yes, it's not intolerant to want to outlaw any positive representation of 10% of the population; but it is intolerant to object to such rampant bigotry.  And we also get some fun talking about offense from, of course, some religious shithead:
"Here's the issue," says Pastor Reshetinsky, a large-boned man with a slight moustache, tells me. "In a real democracy, my freedom and rights are limited by the freedom of someone else."
In his opinion, freedom of speech for sexual minorities is a violation of what he considers his inalienable right not to have to hear something he finds offensive.
Pastor Rechetinsky, let me say with all sincerity, fuck off you despicable example of humanity.  Your "inalienable right" is bullshit, an attempt to oppress people for no reason other than your own petty bigotry.  Oddly enough, the comment about how individual rights are limited by other people is correct; but you think this means your own right not to be disconcerted is more than other people's rights to live their lives normally.  Egocentric bastard.

There's some pretty depressing stuff in that article, such as the poll on Ukrainian's attitudes towards homosexuality.  Over 70% reported a negative opinion.  Not to mention attacks on gay activists, though I must admire one guy:
Despite the formidable pushback - and the threat of physical assault - LGBT activists are undaunted. Karasiychuk, who suffered a broken jaw and concussion in his attack, says gay people cannot retreat into the woodwork.
"We need to be more visible in everyday life. We have to provoke this conversation. Everyone has to ask themselves, why they don't like gays."
I can only wish these people the best of luck.

Wednesday, 10 October 2012

Some thoughts on the Nobel Prize

One of the dangers of working in a scientific field is becoming short-sighted, and thinking that it is automatically the most important area of research.  That is something I think many of us in the particle physics community have been guilty of with regards to the Nobel Prize in Physics this year.  The discovery of a Higgs-like particle at the LHC has been of great significance to us.  It justifies the construction of the LHC, meets the predictions of almost fifty years and opens new doorways to future physics.  For most of us, the only question was how the Nobel committee would resolve the problem of too many candidates; do you award it to the experimental collaborations?  Who among them?  What about the theorists; it's now properly recognised that in addition to Peter Higgs, several other people offered essential insights to the theoretical framework of the "Higgs mechanism".

Of course, the committee resolved this issue by giving the prize to a different field of physics, quantum optics.