The Telegraph’s “depraved sexual fantasies”

A couple of weeks ago, The Telegraph ran an article titled “Women’s sexual fantasies less depraved than men’s“. I didn’t see the article at the time, but it’s clearly gone on to have a big second life on social networks, remaining in the top five most read articles on the site – and with a title like that, it’s not hard to see why. After all, it hits all sorts of popular myths and memes: men are pervs, women are innocent maidens, Fifty Shades of Grey is somehow revolutionary. It’s just a shame that the article itself doesn’t back it up.

First of all, despite what the article claims, this research doesn’t seem to have been published yet. The only record I can find of it is a press release on the University of Granada website, titled “A study Shows that Men and Women Have the Same Sexual Fantasies“. That’s… well, that’s precisely the opposite of what the headline says.

Even The Telegraph admits in the article itself that:

The team said there were not “significant” differences between men’s and women’s racy thoughts, but that there were subtle differences between the sexes in the scenarios that they imagined.

Just as importantly, there’s no way of saying what’s “depraved” and what isn’t (and a Telegraph journalist would hardly be my first choice to draw the line…) Men tended to report fantasizing more frequently about group sex while women said they fantasized more about submission. Why is one more “depraved” than the other?

In fact, talking about what sound like safe, fairly common sexual fantasies in terms like “depravity” is probably just about the worst way you could report on them. As the press release says:

The University of Granada researchers point out that having sexual fantasies “favors some aspects as sexual desire and arousal”. In therapeutic terms, researchers think that it is not only the presence of lack of sexual fantasies what should be considered, but also the patient’s attitude towards them.

If  The Telegraph is calling people depraved for having what seem to be fairly common fantasies, is that really going to improve their attitude towards them?

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No drug is tested on humans, except all the drugs tested on humans

Another day, another “science” piece on Comment is Free that plays fast and loose with the science. Let’s get this over with.

When a dog with a life-threatening uterine infection was recently carried into my veterinary practice, I was confident we could save her. Following a rapid infusion of intravenous fluids and antibiotics, I performed emergency surgery. Partly because of the drugs she was given, “Annie” recovered well. I had the luxury of knowing they had all been tested on other animals of the same species, and were unlikely to inadvertently cause any harm.

Unfortunately, my brother does not have that luxury. He works as a resident in a hospital emergency department, and although the drugs he uses have also been thoroughly tested on animals, this doesn’t provide quite the same level of comfort. It is one of the tragedies of modern medicine that adverse reactions to pharmaceuticals cause thousands of potentially avoidable deaths.

Sadly, dogs are just as susceptible to drug side effects as humans are. But more importantly, “I had the luxury of knowing they had all been tested on other animals of the same species […] my brother does not have that luxury“? That sounds to me like a fairly strong implication that drugs are never tested on humans. This is obviously, blindingly untrue. Any drug has to go through multiple stages of human testing, from safety tests in healthy volunteers, to short laboratory tests, to huge randomised trials involving thousands of patients – sometimes lasting decades. At every stage of the process, the patients are carefully observed, and (in theory*) any side effects are noted and analysed. Indeed, Andrew Knight admits this in the next two paragraphs:

Modern drugs are more carefully studied than ever before. After lengthy tests on animals, those considered safe, and potentially effective, enter very limited human trials. About 92% are then weeded out and deemed unsafe or ineffective.

The remaining 8% are some of the most closely scrutinised compounds on the planet. You might be forgiven, therefore, for assuming they are safe. But at least 39 studies over three decades have ranked adverse drug reactions as an important cause of hospital deaths. Only heart disease, cancer and stroke are more reliably lethal.

No drug is ever tested on humans, except for every single drug ever, all of which are tested on humans!

Adverse drug reactions are always something drugs companies should try to reduce, but for the vast majority, it’s not the case that they weren’t picked up in testing – cases like thalidomide, where no-one knew the risk until pregnant women started using it, are the exception, not the norm. Most adverse side effects that are known about and carefully measured, and the doctor will have had to measure up the risks versus the benefits for each before prescribing the drugs – if you look at the study he links to, 75% of severe reactions to drugs are known side effects caused by dose, and a lot of the rest are allergic reactions. As the paper itself says “This may suggest that many [adverse drug reactions] are due to the use of drugs with unavoidably high toxicity.” We could test as hard as possible, but there would always be drugs that could never be 100% safe.

The author of the piece, Andrew Knight, has written a book on the subject, linked to in the piece (it also apparently focuses more on data than debate, which is usually good, though admittedly the only scholarly review I could find accused the book of bias in the way it analysed this data – Knight’s rebuttal is here), and he does seem to be someone knowledgeable in the field. But that doesn’t change the fact that this particular column is bad. It defends a reasonable viewpoint – let’s try to find ways to test drugs on computers or in petri dishes rather than having to use live animals – with nonsense. Even if we did everything this column recommends, and managed to completely replace animal testing with simulations, I don’t see how it’d cause a significant change in the number of reactions to drugs. It might plenty of other good effects – not least, reducing the number of animals used, of course – but that wouldn’t be one of them.

* Sadly, some pharmaceutical companies have tried to hide the safety data for their drugs – just last week, GlaxoSmithKline was fined $3 billion for doing so – but as things stand, this would happen regardless of whether the safety data was from animals, humans or computers.

Did GM soy cause allergies to soar? Probably not.

So, California’s planning a referendum on the labelling of genetically modified food. The Guardian has covered this not in it’s regular news pages, but in its Comment is Free section, under the title “How California’s GM food referendum may change what America eats“.

The article is mostly an opinion piece – fair enough – but there’s one statistic buried in there that leapt out at me.

While researchers have not yet found a “smoking gun”, which would prove that GM foods as a class are dangerous, there are troubling signs that they may be a factor in the recent epidemic of food allergies. Soon after GM soy was introduced to the UK, for example, soy allergies escalated by 50%.

The link there doesn’t go to a scientific paper, but to a piece on “News. Controversy. Opinion.” site Opposing Views, and their figures seem to come, ultimately, from American Academy of Environmental Medicine, a group that has some decidedly quackish views on topics like water fluoridation, vaccines and “Multiple Chemical Sensitivity” (a scientifically unfounded belief that everything in modern society contains toxins). It’s not impossible to support some outlandish ideas while being right about things, of course, but it does ring some alarm bells.

Neither article links to any of the studies it referenced, but with a bit of digging, I found this piece at Academics Review which seems to be dealing with the same statistic. Go there if you want the full takedown, but in a nutshell, it refers to marketing information from a group called “York Nutritional Laboratories” (which sell food allergy testing kits) the rise was in people with a particular antibody, not those who reported allergies and the study didn’t find any connection (the rise simply happened at a similar time to the introduction of GM, although it actually took place before GM soy became mainstream).*

I decided to have a look on Google Scholar for papers looking in the allergenicity of GM soy. There are plenty of studies and review papers looking into this – one, two, three, four, five – and all the ones I’ve found so far suggest that genetic soybeans and GM soybeans pose exactly the same risk of allergy (though as far as I can tell, these are all animal trials. There isn’t much data on human soy allergies out there).

In this case, the claim that GM soy may be responsible for a rise in allergies seems to be simply wrong.

* For the other major claim in Opposing View’s piece, about baby rats dying from eating GM soy, see this peer review of the paper, originally from Nature Biotechnology , which expresses grave concerns about the unusually high numbers of deaths in the control group – it looks like bad care killed the rats, not the soy)

Mitochondria donation nonsense

A bunch of mitochondria just hanging out.

For various largely uninteresting reasons, I’ve not blogged lately. But then I came across this article on The Guardian website today, a for-and-against piece about mitochondria donation with an “against” argument from Peter Saunders that veers from irrelevant to flat out wrong. Let’s get started!

To begin with, this is not about finding a cure. It is about preventing people with mitrochondrial disease being born. These new technologies, even if they work, will do nothing for the thousands of people already suffering from these diseases, or for those who will be born with it in the future.

Now, here’s the first dodgy argument, one that I’m almost tempted to call a dog-whistle. Mitochondrial donations are not about “preventing people with mitrochondrial disease being born“, they’re about “preventing people being born with mitrochondrial disease”. Just look at how moving that phrase “being born” a few words to the right changed a factual statement about the procedure into a non-sequitur about abortion.

It’s of course true that unfortunately, this procedure will do nothing to help people that already have mitochondrial diseases – removing a mutation from the body is perhaps the most impossible thing in all of medicine – but that’s no argument against the procedure.

Also, Saunders claims that there is no need for the procedure when egg donation is already possible. Bear this in mind; it’ll come up again later.

Will it work? This technology uses similar “nuclear transfer” techniques to those used in “therapeutic cloning” for embryonic stem cells – which has thus far failed to deliver, and animal-human cytoplasmic hybrids (“cybrids”). […] Yet cybrids are now a farcical footnote in history. They have not worked. Ironically, it was in that same act of parliament that provision for this new research was also made.

First of all, cybrids were legalised in 2008. 3-4 years is not that long a time in medical research, especially for research into slow-developing, long-term conditions like Alzheimers and Parkinsons. But I decided to have a look on Google Scholar, to see if cybrids were just a “farcical footnote”. Since 2008, there have been at least 362 papers about cytoplasmic hybrids, including 114 in the last year and a half or so. Some of these are papers exploring the ethics of the procedure, but an awful lot are detailing actual breakthroughs made using these cytoplasmic hybrids.

Embryonic stem cell research, being far more mature, is even more successful, with stem cells relieving paralysis in rats and the first clinical trials in humans showing promising results. Hardly a field that has “thus far failed to deliver”.

But even if he was telling the truth, and both fields had proved to be dead ends, this would still be irrelevant to mitochondrial donation. All it says is that mitochondrial donation uses one technique which is also used in stem cell research. As far as arguments go, this is up there with “vegetarians are evil because Hitler was a vegetarian”.

Is it safe? No. Each technique involves experimental reproductive cloning techniques and germline genetic engineering (that is, it affects the genes passed on to children) – both of which are highly controversial and potentially dangerous. Cloning by nuclear transfer has so far proved ineffective in humans and unsafe in other mammals with a large number of cloned individuals spontaneously aborting, and others suffering from physical abnormalities or limited lifespans.

Well, it’s good thing there’s no cloning involved with this technique, thus making that last sentence completely pointless scaremongering.

Also, as the Guardian noted last week, any changes, or unpredicted genetic problems (mutations) will be passed to future generations.

This is true, but the thing is: if a woman with a mitochondrial condition doesn’t use this technique and conceives a child naturally, there is a 100% guarantee that the mitochondrial defect will be passed to the future generation(s). The whole point of this method is to reduce the number of dangerous mutations being passed on.

Is it ethical? No. A large number of eggs will be needed, involving risky and invasive “harvesting” for women donors. How many debt-laden students or infertile women will be exploited by the offer of money, or free IVF treatment, in return for their eggs? How many embryos will be destroyed?

Ok, so, remember how earlier egg donation was a totally ethical alternative to mitochondrial donation? Well, with a deft sleight of hand Saunders is now claiming that egg donation is unethical!

There are concerns about paying people to donate body parts/fluids – it’s one of the most hotly discussed areas of bioethics – but in the UK, donors are not paid to donate eggs. They can have their travel and accommodation expenses paid (up to £750), but that’s it. There’s simply no room for the kind of exploitation Saunders worries about.

As far as I can tell, there is no difference to the egg donor between standard donation and mitochondria donation. The technique doesn’t necessarily require any extra eggs – though I suppose that depends on its success rate, which, since the technique is still experimental, no-one yet knows – and it doesn’t require any more embryo destruction that IVF or standard egg donation.

Then there are the issues of identity confusion for the children, who in effect will have three biological parents. Some mitochondrial diseases are much less serious than others. Once we have judged some affected babies not worthy of being conceived, where do we draw the line?

The mitochondria are, as the standard explanation goes, the little power stations that fuel each cell, and mitochondrial DNA has no effect on the wider body outside these power stations. A baby conceived by mitochondria donation is closer to having two parents than than a baby conceived by standard egg donation (since in mitochondria donation, all the DNA that affects what the baby actually looks like comes from the mother, not the donor), and if “identity confusion” is a concern, it’s odd that he’d endorse adoption either. And this technique does not mean any baby is “not worthy of being conceived” (unless he’s referring to the parents’ choice not to conceive naturally in the first place, in which case his argument is grosser and more unethical than I thought) – conception will still happen, it’s just that egg will be slightly modified first.

This debate is not being handled responsibly. The research scientists involved have financial and research-based vested interests, and getting the regulatory changes and research grants to continue and extend their work is dependent on them being able to sell their case to funders, the public and decision-makers.

I don’t think “I’m a research scientist and I want to continue my research” counts as a vested interest. It’s not like researchers are pretending their research isn’t dependent on this technique being allowed. I genuinely wonder how Saunders would prefer this debate be handled – he certainly never explains. Speaking of not handling debates responsibly, though neither Saunders nor The Guardian point this out, Saunders is the CEO of the Christian Medical Fellowship, a group that speaks out against a variety of medical techniques on religious grounds. As Mark Henderson said on Twitter, “Saunders makes many bad arguments vs mitochondrial transplants, omitting real reason he opposes: religion […] Nothing wrong with opposing embryo research for religious reasons, but those who do should admit it, and that no evidence would convince them”

Let’s concentrate on finding treatments and providing better support for affected individuals, rather than spending limited health resources on unethical, risky and highly uncertain hi-tech solutions that will most likely never deliver.

We already know that, no matter how difficult mitochondrial donation is, finding a cure for mitochondrial disorders is far far harder still – and perhaps impossible with our current knowledge of genetics. A human body contains billions of cells, each one containing at least one and often tens or hundreds of mitochondria. Replacing or fixing all of them would be far more difficult than replacing the mitochondria in a single cell; if you want an efficient way of spending limited health resources (really, limited research resources – the funding for this research would not be directly linked to the NHS), donation research is surely a better route to take.

(I intended to, for balance reasons, point out any inaccuracies in the response from the Nuffield bioethicist arguing for the procedure, but it already seems pretty sensible and fair. Quelle surprise…)

Edit: Also thanks to Mark Henderson for pointing out that the research is being carried out at Newcastle University and entirely publicly funded by the Wellcome Trust and the Medical Research Council – there are no vested business interests involved either.

The EU, prunes, and the problem with “patent truth”

Hey! I know it’s been a while since I blogged. Hopefully you haven’t missed me too much. Anyway.

Prunes are not a laxative, EU rules, says today’s Telegraph, endowing the EU with frankly godlike powers. Did someone in Brussels snap their fingers and magically prunes suddenly ceased to be laxatives?

Let’s help the Telegraph and suggest a more accurate headline. Perhaps…

Prunes are not a laxative, science suggested two years ago

The laxative effect of prunes is one of those things that “everyone knows”.  Certainly MEP and frequent talking head Roger Helmer agrees, claiming:

“The euro is burning, the EU is falling apart and yet here they are: highly-paid, highly-pensioned officials worrying about the obvious qualities of water and trying to deny us the right to say what is patently true.”

Ignoring the fact that this study was carried out in mid-2009, before the Euro crisis kicked off, Roger Helmer has an interesting definition of “patently true”.

The study looked at the scientific evidence for the effectiveness specifically of dried prunes. There were two studies of the effectiveness of dried prunes in humans at the time:

“Daily Consumption of Dried Plum by Postmenopausal Women Does Not Cause Undesirable Changes in Bowel Function” by Edmund Lucas et al and “Consumption of prunes as a source of dietary fiber in men with mild hypercholesterolemia” by Lesley Tinker et al. Lucas found that there was no significant difference between apples and prunes in stool bulk, consistency, frequency or pain, and Tinker found a difference in stool weight between prunes and grape juice, but no effect on consistency or frequency.

A third study they looked at, “Prune juice has a mild laxative effect in adults with certain gastrointestinal symptoms” showed that as you can probably guess from the title, prune juice did appear to have laxative effects – hence why they only talk about dried plums in the report.

Now, it’s possible that dried prunes are laxative – a much more recent study (albeit one funded by the “California Dried Plum Board”) from 2011 found that prunes appear to work better than the laxative psyllium at relieving constipation – but at the time this report was written, it simply would not have been accurate to say that, based on the body of available evidence, prunes were any better at keeping you “regular” than any other sort of fruit.

(The Telegraph also claims that the EU banned claiming that drinking water could prevent dehydration. Read the actual article, and the very last paragraph reveals that they’re talking about clincal dehydration, which is normally caused by disease rather than by not drinking enough fluids and that “This claim is trying to imply that there is something special about bottled water which is not a reasonable claim”)

Edit: Just found this excellent post by Martin Robbins about the dehydration claim.

Is it a meteor? Is it a plane? No it’s… a star

One thing The Mail normally does quite well are giant picture spreads – stories with lots of giant photos and maybe a couple of hundred words of text to explain them. Normally…

Am I being pedantic? I don’t care; the “spiralling meteors” are not meteors, they’re stars! As the Earth turns, the stars seem to rotate around the Pole Star (the “stationary” speck of light in the centre of the image), and if you take a long exposure photograph of them they seem to draw circles in the sky. Now, there are meteors in this image but they are not spiralling and they are, err, a bit tricky to see, especially since The Mail has squished the images down to web resolution.

Edit: After I’ve complained about the Mail squashing the image too much, WordPress has gone and squashed it even further. Click on the images to view them unsquashed.

Can you see them? They’re more visible in the full size version, and they do not spiral. In fact, that’s how you tell a meteor from a star – the meteor moves so quickly that the rotation of the Earth has no effect on its apparent path, so it blazes in a straight line across the sky. All in all, this is a great star trail picture, but it’s not the best meteor picture ever, and the way The Mail has presented it means it’s not a meteor picture at all.

As the photographer Mark Humpage says on his website:

The bright moon made watching/capturing difficult this year and the very wide angle shot makes for a good composition but lesser meteor detail.

Incidentally, there are a lot of really good photos on Humpage’s website – not just of stars and satellites, but hurricanes, icebergs and aurorae too – and, unlike The Mail, he knows the difference between a star and a meteor. Enjoy!

The Daily Mail blames “brain chemicals” for riots… the research they cite doesn’t

Daily Mail headline: Rioters have ‘lower levels’ of brain chemical that keeps impulsive behaviour under control

Do they? Well, some of them might, but the research in question wasn’t about rioters at all.

Researchers from the University of Cardiff uncovered a link between impulsiveness and levels of the neurotransmitter GABA in a key brain region.

… Around 30 male university students had their levels of GABA measured using a specialised type of brain scan.

They were also asked to complete questionnaires that assessed different aspects of impulsiveness, a trait known to influence self-control.

Participants with more GABA in the pre-frontal brain region had lower scores for ‘urgency’ – the tendency to behave rashly in response to distress or strong emotions and urges.

There was no connection to rioting in the study. Any connection made in the article is being made by journalists – this article has no by-line, being published solely under the Daily Mail Reporter name, but I think it came from the Press Association originally – and it’s a tenuous connection. You see, The Mail is working completely backwards here – they’ve decided that since people who have less GABA tend to behave more rashly, people who they think behaved rashly must have less GABA. You might as well assume that since every MP is in London right now, everyone in London is an MP.

Besides, although the paper in question, “Dorso-lateral prefrontal gamma-amino butyric acid in men predicts individual differences in rash impulsivity” (in Biological Psychiatry not Biological Society, despite what The Mail claims) did find a connection between GABA and impulsiveness, it wasn’t as strong as The Mail claims:

Figure 1 from the paper (highlights my own)

That’s a graph from the paper, showing the connection between the amount of GABA in one particular part of the brain (along the bottom axis) and how strong the individual’s feeling of urgency was (along the side axis) in two groups (cohorts). There does appear to be a correlation (the R number is a measure of how strong this correlation is; R = -0.7 is a reasonable correlation) but look at the two I’ve highlighted with red dots in cohort 2. These two people have the same amount of GABA in their brains, but one of them was incredibly impulsive while the other was one of the calmest people in the study. Likewise, in cohort 1, while there was a definite tendency for people with more GABA to be less impulsive, just look at that cluster of dots – there are impulsive people with lots of GABA, and cautious people without it.

The best you could possibly say about this article is that maybe on average a rioter* has less GABA than normal, assuming these riots are entirely impulsive and there is nothing at all planned or premeditated about them. But then, why does this study need to be connected to riots at all? The paper came out in July before the riots, it’s not about riots – or any kind of violence at all – and none of the scientists quoted mention them, and to be honest, blaming the riots entirely on brain chemistry leaves a nasty taste in my mouth. As Mindhacks has pointed out, The Daily Mail seems to be going to great lengths to avoid exploring any of the context behind the riots, and this kind of story helps bolster the Mail‘s line that there is no deeper cause of these riots than “criminality pure and simple”.

Wales Online originally ran this story too (here’s the Google cache, and if that stops working, here’s a screenshot), but they’ve since realised there’s nothing in this proving anything about the brains of rioters and have replaced the story with an altogether more reasonable report on the research. Will The Mail follow suit? Let’s see.

* Male rioters at least – the study only looked at men, so there’s no guarantee this correlation is true in women too.

Edit: The researchers behind the study have published a scathing rebuttal in The Guardian, saying “Let us be absolutely clear. Our research has almost nothing to say about rioting, and certainly can’t be used to justify or excuse any type of behaviour.” Despite complaints from the scientists, The Mail‘s article is still online.

Defending tau

The Daily Mail today has a piece about the proposed alternative to the number pi, tau (τ), equal to 2 x π.*

Basically, the reason we might want to change to tau is simple:

Pi is defined as the circumference of a circle divided by its diameter. We came up with this definition thousands of years ago, before modern geometry had taken off, and it’s a perfectly good number.

However, we now know that the diameter of a circle – the distance all the way across – isn’t really the best way to measure a circle. Instead, it’s better to measure the distance the radius of the circle – the distance from the centre to the edge. For example, if you’re working out a planet’s orbit, the distance from the planet to the Sun (radius) is a nice logical thing to measure, but the distance from the planet to the other side (diameter) of its orbit doesn’t really mean anything important.

Since the radius is half the diameter, circumference divided by radius is twice as big as circumference divided by diameter, which is why tau is twice as big as pi.

The definition of 1 radian. The red line (radius) and blue line (arc length) are the same length. By Stannered, CC-SA-BY-3.0

Tau is also nice because it makes working with angles a bit easier. The most natural way of measuring angles – the way you have to do it if you’re doing maths or physics – is to measure them in radians. The radian is defined in terms of the circle’s radius – one radian is the angle you get if you walk around the circle for a distance of one radius. If you travel 2π radians, you travel a distance which is 2 times pi times the radius, or pi times the diameter; in other words, you travel the length of a full circle, 360°.

However, that 2 in there is a bit of a pain. It basically means that, in physics or maths, whenever you’re dealing with a circle or a wave you get annoying factors of 2 popping up in your equations, and unless you’re very careful, it’s easy to forget a factor here or put an extra one in there, making your sums completely wrong. For example, to switch between ordinary frequency and angular frequency (effectively, switching from revolutions per second to radians per second), you multiply the frequency by 2π. This is a change we need to make a lot when working with waves, and it’s so easy to lose a factor of 2 when you’re working with a bulky equation.

That factor of 2 is only in there in the first place because we made the mistake of basing pi on the diameter instead of the radius. If we replaced pi with tau, 1 circle would be τ radians, and that factor of two would disappear. It wouldn’t be a groundbreaking change, but it would still be quite nice, and it would make the mathematics of circles a bit easier to understand. Of course, the hassle of teaching people to use tau instead of pi is probably greater than the benefits, so its unlikely we’ll ever give up pi.

Unfortunately, the Mail is quoting from a (paywalled) interview in The Times with University of Leeds lecturer Kevin Houston, whose and they seem to cut down what he’s said to just:

‘Mathematicians don’t measure angles in degrees, we measure them in radians, and there are 2pi radians in a circle,’ Dr Houston said.

“That leads to all sorts of unnecessary confusion. If you take a quarter of a circle, it has a quarter of 2pi radians, or half pi. For the number of radians in three quarters of a circle, you have to think about it. It doesn’t come naturally.

‘How much simpler it would be if we just used tau instead of pi,’ Dr Houston added. ‘The circle would have tau radians, a semicircle would have half tau, a quarter of a circle a quarter tau, and so on. You don’t have to think.’

Trimmed like that, it sounds like Houston is only promoting tau because he’s too stupid to work out three quarters of two (his Youtube video, linked by the Mail, explaining the mathematics of tau, shows this is not the case). So perhaps naturally, Daily Mail commenters have leapt at the chance to prove that they’re smarter than a mathematician, because really, what do mathematicians know about mathematics?!

If an ‘A’ level Maths student has trouble with the difference between Tau and Pi, then they should be on another course. Any excuse to dumb down the kids and stop them thinking for themselves!

Alan, Frankfurt, Germany (ex pat)

Right on! How dare we dumb maths down by making it slightly clearer!

‘The circle would have tau radians, a semicircle would have half tau, a quarter of a circle a quarter tau, and so on. You don’t have to think.’ …..It may be appropriate for DM readers who like not to think, but I’m afraid mathematicians do think, and aren’t interested in tau, thank you very much.

rupert, Yors4hire, UK

Except for all the mathematicians and scientists who support tau I daresay because they think.

This tau thing is clearly aimed at mindless rote learners but to those of us who actually understand maths, pi expresses something meaningful which is precisely why we refer to it so much.

Vincent, Glasgow

Pi and tau express more or less the exact same thing – the shape of a circle – tau just expresses it in a slightly more logical way.

As a retired Maths teacher this idea lacks intuitive sense. The whole point of the exercise is to relate the circumference of a circle to its diameter – and the ratio is the irrational number 3.14159… The ratio is NOT 6.whatever! That’s the basic theory. Then there are various formulae needed at basic school level: for example, the area of a circle is pi time radious squared. The new formula would be tau times radius squared divided by four: an extra calculation step. Or the volume of a cone pi r squared h…. and so on. And in times of austerity how many schools could afford a new set of textbooks filled with tau? (And all authored by Leeds people, no doubt!) And then there are the millions of calculators with the pi button built in…. No! This idea is like trying to say that from 2012 we’ll all drive on the right – indeed the idea of tau is worse than that because there are regions of the world already driving on the right….. This is a big UM and No No

Andrew, Cwmbran

No, but the ratio of the circumference of a circle to its radius IS 6.whatever (6.28318… in fact). The fact that the area of the circle becomes a half times tau r squared (0.5 τr² – there’s no dividing by four involved) is one of the downsides to tau, but as Kevin explains in the video, there is a deeper mathematical reason why we would expect that half to be there, so while it’s annoying it does make sense.

This is the way you can waste a lot of time while avoiding doing anything of real interest or value to anyone. What a waste of brain cells!! Is this supported by public funds? There are real problems in the world today that are worthy of serious consideration, but when academics waste their time on things like this, they prove that they have no value to society at large and should be dismissed.

Samuel, Dubuque, Iowa

One mathematician making a 5 minute Youtube video in his spare time? How dare he! He should devote every second of his life to curing cancer!

Big Wow… Is “2pi” the only mathematical innovation Leeds University can come up with, it’s best 21st Century contribution to the advancement of mathematics? Talented Maths kids doing their 5 science A levels must be crossing Leeds off as even a 5th choice.

Russ H, Bucks

Again, this is one guy working in his spare time. This is not the only thing the University of Leeds Maths department does! (Incidentally, 55% of Leeds pure maths research is “world leading” or “internationally excellent”, and a further 40% is “internationally recognised”.)

BUT….e^([pi]i)]=-1 and this does not work for tau. There are uses for Pi beyond circles!

Miles, Australia

(This refers to Euler’s identity, e^πi = -1, which gives us a nice way of representing imaginary numbers using angles. And despite what Miles says, it’s all about circles.)

That’s true, it doesn’t. Instead, e^τi = 1. This is even better than Euler’s original version, since we no longer have that minus sign (and all that minus sign told us is that pi radians = half a circle, something we already know). Quite a few comments are like this – “OH NO EULER’S FORMULA IS BEAUTIFUL, WE CAN’T CHANGE PI COS THAT WILL BREAK IT” – and yet no-one actually bothers working out what it would look like with tau.

Professional jealousy. Eienstein acceepted Pi and I can assure you he was more intelligent than this egghead. This man just wants to make a name for himself. Change all the books indeed. He is “daft” !

Ruckus, myrtle Beach SC (ex pat)

And why do we bother speaking English? If German was good enough for Einstein, it’s good enough for us!

All those comments have been upvoted, by the way, unlike this comment, which currently has a score of -1:

I am in full favour of this proposition. Unfortunately, a large number of these comments seem be be from people with only a basic understanding of mathematics. Using Tau in place of Pi would reduce the need for a constant in a plethora of standard calculations involving circles and spheres, the like of which children will be schooled in. Furthermore, the simplicity of the equations using Tau may increase understanding and encourage children to pursue an interest into further mathematics. From my experience of mathematics lessons, the majority of students didn’t dislike mathematics, but rather found it too complicated to enjoy. Once provided with a topic they were able to grasp, students began to enjoy working the problems. Once children have achieved a satisfactory grasp of simple circle equations, the transition to understanding the calculus is a much easier one. I think that should the readers have been taught using Tau the comments here would be better informed.

Pep, Manchester

Good old Daily Mail comments, eh?

* They claim the idea was invented by Kevin Houston at the University of Leeds. In fact, it’s much older than that – Bob Palais first came up with it in 2001 – and Houston is just promoting it. Also, as a conflict of interest thing, I guess I should point out that Kevin taught me a few years ago, and is a thoroughly nice guy.

Mobile phones and cancer. Again

(H/T @DickMandrake)

This will be all over the papers today, so here’s a quick run down of what’s actually happened.

Last year the World Health Organisation released its Interphone report (PDF) into the link between brain cancer and mobile phones. For the most part, they found “no increase in risk of glioma or meningioma [types of brain cancer] was observed with use of mobile phones”. However, for very heavy users (the top 10% of the population), there was a statistically significant increase in the odds of developing a form of brain cancer known as glioma but “but biases and error prevent a causal interpretation” – there is too much uncertainty in the data to know whether heavy mobile phone use caused cancer or whether something else was to blame. On the one hand, they found there appeared to be a connection between which side of the brain the tumour developed in and which hand users held the phone in – a sign that phones might cause cancer – but on the other hand, while extreme users experienced a big increase in brain tumours, people who used their phones even slightly less saw no change in brain cancer – a sign that mobile phones might not cause cancer.

Fast forward a year, and the WHO’s International Agency for Research on Cancer (IARC) has issued a press release (PDF) about an upcoming report which, based on the Interphone study and some other papers, will classify the electromagnetic (EM) fields from mobile phones as “possibly carcinogenic to humans” meaning there is “limited evidence” that they may cause cancer. In other words, it’s the exact same conclusion as the Interphone report, but this time the report is focusing on the negative – heavy doses may cause cancer – rather than the positive – light doses probably don’t cause cancer.

That in itself is very reasonable – even if mobile phones carry a very slight cancer risk, the IARC still need to know what that risk is. The problem comes when the media, reporting this in the usual shades of black and white, ignore all this nuance in favour of scares:

The Mail screams “Mobile phones CAN increase risk of cancer: Doctors reveal shock results of major study into effect on the brain“, magically turning “possibly causes cancer” into “CAN cause cancer”. It’s not really a shock result either, since it came out a year ago. The Mail also brings up the recent Council of Europe draft report that suggested banning mobiles from around schools, ignoring the fact it was pseudoscientific rubbish based on research from quacks.

The Express goes for the similar “Shock cancer warning over mobile phone use“, claiming “MOBILE phones have been officially linked to cancer for the very first time by a team of world experts”. Again, the report is a year old, it’s not a shock! They also manage to get in some ridiculous guilt-by-association:

But they classified mobile phones in the same danger category as the pesticide DDT and petrol engine exhaust, meaning they are possibly carcinogenic to humans.

Petrol exhaust and DDT are pretty dangerous, but that’s not necessarily because they cause cancer! Nor does being in the same group as these mean it carries the same risk of cancer, either. It just means that we have the same level of evidence for a cancer risk, which isn’t the same thing. For example, DDT is now banned worldwide, with most developed countries banning it in the 70s. This means that people aren’t being exposed to it any more (a good thing, of course!), so we can’t study its effects and work out exactly how dangerous it is.

The Guardian meanwhile goes for a tenuous connection to the risks of mobile phone base stations and wi-fi, even though the exposure to EM from these is much lower than from holding a phone to your ear – and we know even then it’s only the heaviest exposures that may cause cancer.

The Telegraph also makes the ridiculous DDT comparison, but at least they quote the great Ed Yong, head of health information at Cancer Research UK, who sensibly sums up the evidence:

“The risk of brain cancer is similar in people who use mobile phones compared to those who don’t, and rates of this cancer have not gone up in recent years despite a dramatic rise in phone use during the 1980s.

“However, not enough is known to totally rule out a risk, and there has been very little research on the long-term effects of using phones.”

(They also quote a professor of Medical Physics and Director of the Mobile Operators Association, but to be honest, they seem to have gone into damage control mode before there’s been any damage to control. Pro-tip, guys – if you ever end a paragraph about the health risks of something by saying “The social and technological benefits also need to be emphasised“, then you sound like a cyberpunk bad guy, even if you truly mean it.)

Anyway, for a little perspective, there’s a great interview with Ed Yong about the news here. Read it!

Edit: There are also great pieces out there on this from Pharyngula, Respectful Insolence, Cancer Research UK, Tom Chivers, Only That In You, Scientific American and Bad Astronomer. Good old blogosphere!

Black holes and revelations in the Mail

Edit: After a quick email conversation with the author, the article has now been rewritten (direct link). Although it still has a slightly cringeworthy headline, it no longer contains misunderstandings about the paper and is all in all pretty good! I’ve hidden the original post behind the cut.