Garcinia cambogia

September 19, 2013

I have been growing portlier over the last few years. I don’t weigh myself, so this happened without my being consciously aware of it, although I did notice twinges in the joints as they protested against having to bear stresses for which they had not been intended.

But it was when I realised that I was having more and more trouble bending down far enough to put my socks on that I decided to do something about it. Coincidentally, I received an email at about the same time extolling a substance called Garcinia cambogia as a ‘miracle’ weight-loss medication. Needless to say, I was quite excited by this potentially easy way to lose weight, but as I read, red flags started popping up.
The first of these was that the stuff had been recommended by Dr Oz. Now, Dr Oz has seemingly impeccable qualifications: graduated from Harvard, then received his MD from the University of Pennsylvania, and an MBA from Wharton. He is a professor at Columbia University. Yet he has a record of recommending quack remedies on his ridiculous TV show. Do they not teach anything about the scientific method at those prestigious institutions he attended?
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Future Perfect

September 4, 2013

The presenter of the morning early breakfast show on Cape Talk radio was commenting about the predictions made by Isaac Asimov on the occasion of the World’s Fair in New York in 1964. Asimov was musing on what the World’s Fair of 2014–fifty years later–would look like. “He really is incredibly accurate!” enthused the host, “It’s uncanny how he could have known then what our world looks like now!”

I hadn’t read Asimov’s predictions, so I looked them up to see for myself just how prescient he really was. Not, it turns out, as much as the breathless radio presenter would have us believe. I enumerated 24 specific predictions made in the article, and found that 10 were accurate within reasonable bounds, 12 were inaccurate, 2 were partially accurate.

Some of the predictions that were right on the money were:–
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May 15, 2013

I’m somewhat mystified by this article in the New Scientist. A British Aerospace Jetstream aircraft flew from Lancashire to Inverness in Scotland controlled for part of its journey from the ground.
So what? None of the technology described is new, at least not in concept; and modern commercial airliners are flown by the autopilot most of the time anyway. If you are going to have a pilot, what is the advantage of having him on the ground instead of in the plane? In the case of military drones there is the obvious advantage of the pilot not being killed when the plane comes under enemy fire, and the drone can be designed to be smaller than would be required to carry a human pilot; but commercial airliners are altogether a different kettle of fish.
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Even Odds

January 30, 2013

The laws of probability, so true in general, so fallacious in particular.
–Edward Gibbon

A puzzle has recently been brought to my attention. It goes like this: “I have two children. One of them is a boy born on a Tuesday. What is the probability that I have two boys?” This puzzle was posed to an audience at the Gathering for Gardner meeting in Atlanta, Georgia, by Gary Foshee. He went on to say, “The first thing you think is ‘What has Tuesday got to do with it?’ Well, it has everything to do with it.”
I disagree. The day the boy was born is utterly irrelevant. Perhaps it would be best to look at the “accepted” solution from New Scientist before I tell you why it’s hogwash. Its main point is:

The main bone of contention was how to properly interpret the question. The way Foshee meant it is, of all the families with one boy and exactly one other child, what proportion of those families have two boys?
To answer the question you need to first look at all the equally likely combinations of two children it is possible to have: BG, GB, BB or GG. The question states that one child is a boy. So we can eliminate the GG, leaving us with just three options: BG, GB and BB. One out of these three scenarios is BB, so the probability of the two boys is 1/3.

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Polygraph Testing

March 1, 2012

I received an epistle from the South African Labour Guide yesterday. It was on the subject of polygraph testing and began:

Employers are often faced with dishonest or criminal activities such as misappropriation of property or theft in its work environment, without knowing exactly where, how and by whom it was committed. It is crippling the business and the employer is at its wits-end to find the culprits or wants to know: “Can I send all my employees for a polygraph test and if so, what can I do if they fail?”

It then went on, in answering this question, to miss the point entirely: it didn’t even touch on the scientific validity of polygraph testing. To be fair, the Labour Guide is a guide to labour law, and does not use objective truth as its yardstick; but I would still expect it at least to touch upon one of the best defences against polygraph evidence–that it is pseudoscientific nonsense that has been thoroughly discredited, and whose use should be illegal. It might be instructive to look at how it is supposed to work.

The victim is attached to various wires which connect to a machine that measures heart rate, blood pressure, respiration and skin conductivity. The interrogator will then follow one of two techniques: the control question test (CQT) or the relevant/irrelevant test (RIT). In the IRT the inquisitor will ask irrelevant questions (is your name Fred?), interspersed with relevant questions about which the test is really being conducted (did you plant the bomb?). If the lies (or truth) told in response to the irrelevant show the same physiological responses as those for the relevant questions, then the subject passes the test. The CQT is similar, but additional irrelevant questions are posed that will most probably result in a lie (have you ever lied to avoid trouble?). The assumption is that everyone has lied at some stage in the past, and that if the victim replies to this question in the negative he is lying, which will allow the operator to compare the physiological response to this ‘known lie’ with answers to the relevant questions.
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Richard Dawkins Interview

February 24, 2012

I heard this interview (15.6 MB) on the Redi Thlabi show on Cape Talk. There are some quite interesting points made, and there are some funny moments–poor Redi nearly cracked up with laughter at one point.

Great Green Con

February 2, 2012

I’ve just returned home from my holiday at Knysna on the Garden Route. In our bathroom was a notice informing us that the Garden Route was suffering its worst drought in 130 years and to therefore use water sparingly. Whether or not this drought is an effect of climate change I am not qualified to say, but it did lead me to think about our concern for the environment, and what we are being encouraged to do about it.

The messages the public gets seem to fall into two distinct classes, the first of which contains the general exhortations to be conscious of our impact on the environment, minimising our carbon footprints and so on; and the specific, commercial messages as corporations attempt to cash in on the new environmental awareness. It is with this second class of message that I have a problem.
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