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* Posts by Julian Bradfield

39 posts • joined 19 Jul 2008

Particle that behaves like matter AND antimatter found: Majorana fermion

Julian Bradfield

Re: Special? Maybe in some ways

Where do neutrons come into it, fermions though they be?

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Julian Bradfield

Re: Special? Maybe in some ways

The photon and the Higgs boson are, um, bosons. Not fermions. It's Majorana fermions that are interesting.

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Brookhaven boffins boggle at baryons

Julian Bradfield

Your description is rather misleading - it suggests, without quite saying, that strange baryons haven't been observed. It's certain heavier strange baryons, predicted by particular models, that haven't been observed - we've been playing around with strange (Sigma), doubly strange (Xi or Cascade) and triply strange (Omega) baryons for half a century.

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Google's Pankhurst doodle doo-doo shows the perils of using Google to find stuff out

Julian Bradfield

What on earth is your point? June Purvis' biography of Pankhurst also says the birth certificate says the 15th. If you want to argue that the birth certificate is wrong, you should have some actual evidence. As there is none, Wikipedia correctly goes with the evidenced date.

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Angelina Jolie 2.0 NOT an inspiration for Huawei phones, says exec

Julian Bradfield

Re: Correction

As any fule know, honorary knights and dames do not have the title "Sir" or "Dame". You mean:

that's stick-thin-slighty-scary-actress-turned-humanitarian-crusader Angelina Jolie DBE to you.

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London commuter hell will soon include 'one card to rule them all'

Julian Bradfield

Re: Oh dear...

You have to keep a non-trivial sum on it, because they won't let you on unless you have enough to pay for a "reasonable" journey.. The only way to top it up free is with cash or a Dutch bank card. And they want to make it the only means of payment. At present, they have a surcharge for not using it.

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Teen jailed for ARMED ROBBERY says he and pals had been inspired by Grand Theft Auto

Julian Bradfield

The question (when asked by people with half a brain) is not "do video games make people kill people?". The question is "do video games increase, society-wide, the number of people getting killed?". If the answer is "yes", then you ask "how much", and "is it worth it?". Compare guns: the NRA slogan "guns don't kill people, people kill people" is completely correct. Nonetheless, the widespread availability of guns to random idiots appears to significantly increase the number of people who get killed. Thus most of the world restricts availability. Similarly with private use of motor vehicles.

There is a whole bunch of research on whether violent video games tend to make people more violent in reality, and it's not a trivial question.

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95 floors in 43 SECONDS: Hitachi's new ultra-high-speed lift

Julian Bradfield

v^2 = u^2 + 2as is the equation that surfaces from the 35-year old physics lessons.

u = 0, v = 20 m/s, s = 220m, so a = 0.9 m/s^2, or a mere 0.1g.

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Enterprise storage will die just like tape did, say chaps with graphs

Julian Bradfield

just like tape did?

We get articles here every few months pointing out that tape is still going strong, and showing no signs of dying out!

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First Direct 'Secure Keys'

Julian Bradfield

how's the secure code made?

As far as I can see, there's no challenge, just a response. If it's a one time pad, what happens if it gets out of sync? If it's not a one-time pad, what's it doing?

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Earth's night-side gets different kinds of neutrinos from day-side

Julian Bradfield

Andy the Hat: Those who mark A-level Physics can generally read the sign of the reported result correctly.

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The Sun ERUCTATES huge ball of GAS at 4 MILLION MPH

Julian Bradfield

That would be "with *us* puny humans".

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Boffins say D-Wave machine could be a classic*

Julian Bradfield

Re: Church's Thesis

Quantum computers are not more powerful than classical computers in the Turing sense. They are just faster. Church's thesis is still going strong - to break out of it, you need to muck around with black holes or the like.

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If you want an IT job you'll need more than a degree, say top techies

Julian Bradfield

Re: A time machine helps, too.

Modern Unix equivalent: for f in *.x ; do mv $f ${f%x}y ; done

Somewhat easier to read and do, I think...

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Deploying Turing to see if we have free will

Julian Bradfield

Re: As Sir Roger Penrose pointed out years ago

I did read the book. It's unlikely that Penrose knows more about Gödel's theorem than I do - it's not his field, and it is mine. Your (vague) statement of the incompleteness theorem is incorrect, and your `argument' fails in the second line, because we can't see that the Gödel sentence is true - we can only see that either the Gödel sentence is true, or the theory is inconsistent. (The proof of incompleteness takes a theory T, constructs its Gödel sentence G, and then says EITHER G is true (and hence unprovable in T, because G says "G is not provable in T") OR G is false (in which case it is provable in T, and so T is inconsistent). Given any particular theory, we can't tell which of those is the case, because we have no way of determining whether a theory is consistent (except by using a different theory, which we then can't prove consistent...).

The formal statement of the theorem doesn't mention "truth" at all, because can't be pinned down in any reasonably powerful theory. It simply says there is a statement such neither the statement nor its negation can be proved by the theory.

So if you want to argue that humans are more powerful than computers, you need a more refined argument than that.

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Julian Bradfield

Re: As Sir Roger Penrose pointed out years ago

Gawd. There should be a licence required to use the name of Gödel.

Penrose may have been a decent physicist, but as a logician he's what we in the trade call a "crackpot".

The incompleteness theorems say nothing at all about understanding, because understanding is not a mathematical concept. They merely say that any (suitably powerful and well-behaved) mathematical theory has things it can't prove. The incompleteness theorems themselves are NOT things that the system can't prove: they are proved in ordinary logic, and are no harder to understand than many other theorems.

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How to spot a coders comment

Julian Bradfield

XEmacs has lots of vigorous comments, as you would expect from something on which Jamie Zawinski worked. Such as

/* #### urk urk urk!!! Chuck fix this shit! */

and then a few hundred lines later

/* #### Chuck fix this shit or I'm gonna scream! */

The comments are at least 15 years old, and Chuck (who is still around) still hasn't fixed them.

(#### is code for "major screwage that should be fixed for the next release")

There ain't no passive aggression in XEmacs!

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MacBook Air fanbois! Your flash drive may be a data-nuking TIME BOMB

Julian Bradfield

just out of curiosity...

what do you call a female fanboi?

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The importance of complexity

Julian Bradfield

The importance of complexity

In a vigorous discussion about revising courses in a computer science degree, one of my colleagues opined that "every decent programmer is sometime going to come across a task that is NP-hard, so they need to know to tackle NP-hard problems".

I'm curious as to whether anybody on here (who is a programmer after going through a so-called top university's CS degree) has ever been asked to solve a task that is computationally intractable, and if so whether they used the last couple of decades' work on such things to solve it.

Come to that, how many CS graduates ever solve algorithmic problems, rather than systems engineering problems?

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So, Linus Torvalds: Did US spooks demand a backdoor in Linux? 'Yes'

Julian Bradfield

A biased sequence can still be random in some senses. The comment to which you reply is correct: all pseudo-random sequences are deterministic, because that's what the term means: a pseudo-random sequence is an algorithmically produced sequence which passes whatever your favourite statistical tests for randonmess are.

You're correct that non-determinism and randomness are different: in mathematical modelling of systems, a "non-deterministic" choice is one that is not made by the system of interest, but by its environment: e.g. a vending machine has a non-deterministic choice between receiving a "tea" button press and a "coffee" button press, as which one happens depends on the environment (the user). In theory of computation, a non-deterministic algorithm really means one where all possible choices are explored in parallel; or alternatively, you can take a lucky guess as to which choices you should make.

"Random" refers either to statistical properties of a sequence - and such a sequence can be a determined thing, just not determined by any computable function - or to a primitive notion of probability. In the probabilistic case, biased outputs are included: for example, if you generate a sequence of bits every second by seeing whether an atom of uranium has decayed in that second, that sequence is, as far as we know, truly random in every probabilistic sense of "random". The ratio of zeroes to ones, however, depends on how much uranium you have. In the algorithmic case, a biased sequence is not random becase it can be compressed - if the string has ten times as many zeroes as ones, then you can trivially compress it by coding sequences of zeroes, and you'll win - but it can still be a random sequence in the probabilistic sense.

Cryptographers want sequences that are random in both senses.

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Jurors start stretch in the cooler for Facebooking, Googling the accused

Julian Bradfield

standard of proof for contempt

Para 2 of the judgement says "The law in relation to proof of contempt at common law is well settled. First the Attorney General must prove to the criminal standard of proof that the respondent had committed an act or omission calculated to interfere with or prejudice the due administration of justice"

Where does the bootnote statement about it being balance of probabilities come from?

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Angry Birds fire back: Vulture cousins menace UK city's mobiles

Julian Bradfield

perhaps ElReg should buy its contributors dictionaries?

"more paramount", indeed. That's even more nonsensical than "more unique".

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Ahoy! Google asks US gov't to help sink patent 'privateers'

Julian Bradfield

Re: Is there another side?

Sigh. Apple did not file for a patent on rounded corners. It filed a registered design (in European terms, or a design patent in US terms) which is very different from a patent. It included seven characteristic features of the design, of which rounded corners formed one. The case was about whether Samsung's phone, *as a whole*, had been designed to look like Apple's registered design.

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Six things a text editor must do - or it's a one-way trip to the trash

Julian Bradfield

why not use an IDE

Because of the incredible bloat. I recently wanted to write a simple app for my ancient Nokia phone. I tried to do it The Right Way: downloading the entire Nokia development environment, and running under Wine (of course, doesn't work properly under Linux). Gigabytes of download, including a custom Eclipse; then you have to *run* Eclipse, which takes months to learn how to use (I've even taught using the damn thing, but have blissfully forgotten it all). After a few days of struggle, I thought, somebody must have done this the really right way - googled, and found a nice simple Makefile of a few lines that does everything. So now I can edit my tiny 600 line app in emacs like everything else, compile it with one command, and throw away the gigabytes of Eclipse and irrelevant Windows java libraries.

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Yet more world+dog patent suits, this time over encryption

Julian Bradfield

Re: Not a Troll

Emacs has had crypt mode, with automatic en/de-crypting of files on read and write, since 1988 at the latest. How does it do it? It adds a software module (crypt.el) to an electronic document management system (Emacs) which traps file i/o events (load, save) and applies crypto.

General encryption of *any* (non-setuid) Unix program by using LD_PRELOAD to hook into the file i/o at the system library level has been around since well before 1998.

And surely IBM have been hooking crypto into file i/o since the year dot?

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Perl programming language marks 25th birthday

Julian Bradfield

Re: Perl

Errmmm .. in sh $? returns the exit code, not the the wait(2) status.

Perl's decision is very surprising for shell programmers.

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Police mistake reveals plan for Assange's Embassy capture

Julian Bradfield

Re: so10

Er, no, embassies remain the sovereign territory of the host country. Go read the Vienna Convention (or the implementing law).

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Humanity increasingly sitting on collective arse

Julian Bradfield

logic fail

I think you (the author) meant "can achieve by failing to meet *all* of the following criteria".

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Watch out for the GIGANTIC ALIEN JELLYFISH, warns space boffin

Julian Bradfield

In which case she has one smart donkey.

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GNOME emits 'head up the arse' desktop update

Julian Bradfield

Nobody else using fvwm2, then?

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Provider: Anti-piracy ruling has 'killed Usenet'

Julian Bradfield

Just as a point of fact, the use of "piracy" to describe unauthorised copying goes back to the 17th century - before there was copyright!

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BOFH: I'll get my bonus even if it kills, well, someone

Julian Bradfield

It can be a discourse marker rather than a grammatical marker. Seems to originate in Irish English. See Seamus Heaney's introduction to his Beowulf translation, where he translates the opening "Hwæt!" as "So!".

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Rackspace backtracks over toff-proof sign-up process

Julian Bradfield

webdeveloper

Often, the "validation" (rejection of perfectly good email addresses) is done by javascript in the page. Using nice toys such the Web Developer Firefox plugin, it's easy to modify the page...

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Brits unleash world's hottest chilli pepper

Julian Bradfield

Significant figures - what they?

1,176,182 ? Yeah, right. That factors as 2 x 7 x 29 x 2897.

We're expected to believe that somebody diluted something 29 times, and then 2897 times?

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HP boffin claims million-dollar maths prize

Julian Bradfield

forgotten some classes?

Since the 1970s, you mean. Gödel came up with the basic idea in a private letter in 1956, but it was only in 1971 that Steve Cook defined P and NP and posed the problem.

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God particles breeding like bosons

Julian Bradfield

oh dear oh dear oh dear

Where did you get that graphic from? Four notational errors in one small table...

The W and Z bosons should be W and Z, not w and z; the photon should be γ (Greek gamma), not y (Latin y); and the neutrinos should be ν (Greek nu) not V (Latin V).

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Ruling makes it easier to get software patents in the UK

Julian Bradfield

obvious to one skilled in the art?

From the "pithy description" quoted at the beginning of the ruling, this "invention"

looks like a bog standard look-up table, and is a trivial application of the maxim

"all problems in computer science can be solved by adding another level of indirection".

Knowing someone who once worked at the EPO, I know their quality control is utter crap;

but how did this get past even the dumbest examiner?

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MoD: We lost 87 classified USB sticks since 2003

Julian Bradfield

armed guards???

Posting of Friday 18th July 2008 23:05 GMT says:

>If you cant handle something as if it was RESTRICTED or less, then you

>typicallyneed to transport it with at least an armed guard, which is quite an

>expensive process.

Oh yeah? As the CPS manual to which you helpfully provide a link says,

you can send SECRET documents in the Royal Mail, as long as you use

Special Delivery. I've never yet seen the postie turn up with an armed guard.

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