Reinventing Me: February 2011

Thursday, February 10, 2011

Aneurin Bevan, The National Health Service, and a Trip To The Doctor

The collective principle asserts that... no society can legitimately call itself civilised if a sick person is denied medical aid because of lack of means.

That's a quote from one of my heroes - Aneurin Bevan, voted in an online poll as the number one Welsh hero, beating out competition even from luminaries such as Tom Jones and Richard Burton. Bevan had worked as a coal miner since the age of 13, and as a union official found himself leading the local miners in the 1926 General Strike. Three years later, he became the Member of Parliament for Ebbw Vale, a post he held right until his death in 1960. He was known for his supreme oratory, regularly exchanging verbal blows with his long-time political enemy, Winston Churchill.

But Bevan's enduring legacy is the formation of the United Kingdom's National Health Service, achieved when he became the Minister for Health and Housing in Clement Attlee's Labour government after the conclusion of the Second World War. He saw "the sale and purchase of medical practice as an evil in itself" and sought instead a program that was "free on the point of delivery". Ninety-seven percent of the British public were signed up within a month of 5 July 1948, the date when his National Health Service Act came into force. While the NHS has often been under attack, most particularly in the past thirty years and especially since healthcare reform has become a topic for discussion in the US, it has endured. In general, most British people are content with their system; during 2009, Professor Stephen Hawking went on record saying that, without the NHS, he wouldn't be alive today. In recent comparisons with six other wealthy nations, the United Kingdom's healthcare system ranked second overall, and number one when it came to efficiency. (The US, the country with the most expensive healthcare system in the world ranked last overall, and at best next to last in any of the dimensions of the study).

OK, I've made my point. I'm a product of that healthcare system. It was there for me when I came into the world; it saw me through my first 25 years as, overall, an exceptionally healthy individual. It's the reason both my parents are cancer survivors. And yet, it seems nobody can even mention healthcare without it becoming political. Why is that? You wouldn't expect your doctor to talk about politics, would you? Today, though, that's precisely what happened. I did something today I have never been able to do since moving to the United States. I went to see a doctor, without actually being ill - well, except for some little minor annoyance. (Cooties, I'm sure. Girl cooties, no doubt. Or her dog. Or her cat.) Why have I never been able to have preventive medical care up until now? Because, quite simply, I couldn't afford it. The last thing I wanted to hear this morning was a treatise about how "socialized" healthcare basically can't get to you until you're about to kick the bucket, and about the superiority of a system for which your insurance would "probably" pick up the tab, and if not, there were plenty of other programs.

He's absolutely right, of course. This is indeed a free market economy, and, as such, standard rules apply. As a paying customer, I am this doctor's employer. I was dissatisfied with his work, and I didn't think he was right for the job. So I did what any free market employer should do with that kind of employee. I fired him. I'll be seeing another doctor for my next visit.

He didn't even address my cooties either, but did suggest I could invest $110 for a slip cover for my bed sheets.

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Wednesday, February 2, 2011

Two navigation technologies, three centuries apart

This blue plaque remembering John Harrison is ...

Image via Wikipedia

(Disclaimer: Although I am employed by Telenav, Inc., a company specializing in GPS applications, there is nothing proprietary included in this article - it is all information readily available from sources such as Wikipedia).

Navigation has changed quite significantly over the years. For quite some time, mariners have been able to calculate their latitude - their distance north or south of the Equator - with reasonable precision; just measure the angle of the sun above the horizon when highest in the sky, adjust for the tilt of the earth and the progress of the seasons, and, with a considerable bit of geometry (quite literally) out comes the result. It takes quite some effort to compute by hand, but such an essential requirement at sea deserves that much attention.

Establishing longitude, however, is a considerably more challenging proposition. In theory, it's quite simple, provided you can accurately tell the time. The notion of time zones is familiar; with every degree of longitude one travels east or west (about sixty nautical miles at the equator), the times of sunrises and sunsets shift by four minutes. In other words, if an accurate clock was set in Greenwich and taken on board a ship, observing the sun at noon and checking the time difference gives the longitude. The problem, though, is to find an accurate timepiece, particularly one that would operate satisfactorily on a ship with wide ranges of temperature, humidity, rough seas, and so on. Measuring longitude precisely was so important to navigation that the British Parliament passed an act in 1714 establishing a prize, worth millions in modern terms, for anyone who could suitably make progress in this field. John Harrison was a man who dedicated his entire life to this problem, making succession after succession of better and better chronometers; quite a tall order for the times. The terms and conditions of the prize required an accuracy better than sixty miles for an Atlantic crossing before any money would be paid; as mentioned above, that requires the clock stays within four minutes of true over the entire trip.

Nowadays, with atomic clocks and GPS, it seems the problems of three hundred years ago are far behind us, but in fact, even GPS depends on something very similar to the longitude problem. While most people have some ideas exactly how GPS works, there may be some surprising details. Basically, GPS satellites transmit time signals. A receiver can read the time signal, compute exactly where the satellite should be at that time based on its known orbit, calculate the time the message took to arrive and hence the distance to the satellite, and, with a bit of triangulation from multiple satellites, work out exactly where on the Earth the receiver is. At least, that's the theory - but, with a little thought, you'll realize that can't possibly work.

Radio waves travel at the speed of light, three hundred million meters per second. Even if time measurements for GPS were accurate to a millionth of a second, that's three hundred meters - hardly the sort of accuracy everyone expects from their navigation devices. And the quartz crystals in our mobile devices - yes, those very same quartz crystals that were vaunted for their accuracy when they were included in digital watches - are nowhere near as accurate as that. (The important thing about quartz crystals is not their accuracy - it's that they're ridiculously cheap). If the clocks in the mobile devices drift, it would be very difficult to compute a position on Earth; in fact, the position calculated would be thousands of miles off and maybe not on the planet at all. So how can GPS achieve the results with the accuracy we're used to? Is there another John Harrison who found a way to measure the time more accurately?

Almost. Instead, the problem is solved in a slightly different way. Instead of using GPS to locate our position in three dimensions (which would in theory take three satellites), we have to also locate ourselves in a fourth dimension, time, which takes four satellites. In essence, while our devices will incorporate an error in any time observations, that time error should be pretty much the same for all of the GPS satellites that are being observed. The time error produces what is known as a dilution of precision. The more satellites that can be seen, the more precise the calculable result. Although it might seem that your GPS device or navigation program can position you precisely, it requires a considerable number of measurements from ever-moving satellites to get that precision, not to mention a fair amount of mathematics. Something worth thinking about, when you find yourself literally holding what was once a secret Department of Defense technology in the palm of your hand.