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Peter Nixon
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Thursday, 31 October 2002
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Monday, 28 October 2002
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Saturday, 26 October 2002
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Thursday, 24 October 2002
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Wednesday, 23 October 2002
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Monday, 21 October 2002
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Sunday, 20 October 2002
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Saturday, 19 October 2002
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On the subject of Bush, here's a bit of fun.
3:42:51 PM 
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Check this out.
It's a very interesting analysis of President Bush's October 7 speech about Iraq.
3:35:25 PM
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Friday, 18 October 2002
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Relative risks and snipers, or, how I learned to stop worrying and live my life. The "experts" have been coming out of the woodwork to talk about the Washington DC sniper murders, currently occurring all around where I live. A lot of "advice" is being thrown around concerning what people should and shouldn't do. But can we really trust that advice and does it have any foundations? To answer this question we really need to understand the nature of risks and relative risks.
For example, I have heard some "experts" recommend that people should fill their car fuel tanks at places away from major roads. Doing so may reduce your risk - we don't really know by how much - but it will almost certainly increase other risks, such as the risk of being killed in a car accident because you spent longer on the road.
At this point most people say, "Hang on, the increased risk of a car accident is minuscule, and there is a much reduced risk associated with staying out of the sniper's fire." But this argument may not be valid. Our intuition with regards to risk assessments are notoriously poor. Essentially every study on the public understanding of risk shows that people just can't estimate levels of risk when the risks are extremely small.
I don't know which change in risk is greater - I haven't tried to work out the numbers, and I suspect that they would be very difficult to calculate with any decent precision. But it seems entirely possible that these two changes in risk could balance each other out or you could increase your risk by driving a greater distance on less familiar roads more than you decrease your sniper risk.
Another example, just to show this isn't an isolated piece of advice that has an uncertain statistical basis: Some commentators are recommending that you don't walk in straight lines as this makes it harder for a sniper to target you. Considering that a walking person is already a difficult target and the sniper seems to have chosen stationary victims in most cases, how much does this decrease your risk? Then consider what risks it increases. Walking erratically increases the chance of tripping and falling, hitting your head, and your brain hemorrhaging. It increases your chance of stumbling in front of passing traffic, perhaps to be hit by the person driving to a different fuel station, unaware that pedestrians walk so close to the road in this area...
These increased risks may seem ludicrously small but how much did you decrease the risk by walking erratically in the first place?
The point is that we can't make valid recommendations about how to change behaviour unless we try to work out these statistics. Practically any change of behaviour will result in increased risks. Do we know for sure that increase is compensated for by the risk decrease we are aiming for?
Perhaps we shouldn't be changing our behaviour at all. What are some comparable risks?
We need to make a couple of assumptions to make any meaningful comparison. Assume that the series of shooting stops, for whatever reason, in a month. Assume that an episode like this only happens in the DC region once every decade. (This is probably an overestimate of the risk but we'll stick with it for now.) Then the risk of being shot by a sniper in the DC area is about 24 in 3.5 million per decade (the 24 is the number of expected shootings in a month - again, this might be an overestimate if the shootings are now at 3 or 4 per week.) This works out to a risk level of about 7 in a million per decade.
Now for some comparisons: the chance of dying in a car accident, as the driver, is about 240 per million per decade. The chance of dying from a fall at home is about 90 per million per decade. The chance of being hit by a car, as a pedestrian, is about 15 per million per decade. The chance of being hit and killed by lightning is about 1.5 per million per decade.
So you are only slightly more likely to be shot by the sniper than hit by lightning. You are twice as likely to be hit by a car while walking down the street than being shot by the sniper. You are more than ten times as likely to trip and fall at home than being shot by the sniper. You are 35 times more likely to die in a car crash while driving than being shot by the sniper.
When you go out of the house, do you worry about dying from driving, being hit by a car, tripping over and falling to your death, or being hit by lightning?
Perhaps you want to argue with the details of the statistics but I have been aggressively overestimating the risks from the sniper and they still come out far lower than a lot of everyday activities, including ones that we have no control over.
The take home message: don't trust your instincts about risk and be careful how you change your behaviour in response. It's entirely possible that you could be increasing your risk by being too worried.
(Note: some of the data I used to estimate risks came from here. The data may not be perfect for the DC area but I would expect it to be something like this.) [David Harris: Science news]
1:11:18 AM
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Indonesia at the crossroads. The terror attack in the world's most populous Muslim nation could stir up rage against Islamic extremists, says an expert. But if the U.S. invades Iraq, all bets are off.
[Salon.com]
12:49:49 AM
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Am I being unreasonable?
The New York Times Has an article (quite reasonably) on three victims of the Bali bombing. What makes me uneasy? It's that assumption that only Americans matter, only Americans grieve. I know I'm overstating this, but this is certainly what came across a year ago with the twin towers. Americans cared for lost loved ones, but it didn't matter so much that as a consequence the odd wedding party would be bombed in Afghanistan. Were there no grieving families for those dead?
Surfing, Teaching and Rugby Drew 3 Americans. The three Americans who are thought to have been killed in the Bali bombing represented the diverse reasons that send people to the far corners of the earth.
[New York Times:International]
12:20:02 AM
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Thursday, 17 October 2002
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Wednesday, 16 October 2002
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Tuesday, 15 October 2002
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Monday, 14 October 2002
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"The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science. He to whom this emotion is a stranger, who can no longer pause to wonder and stand rapt in awe, is as good as dead: his eyes are closed." -Albert Einstein
[Rick@Leaders.net: Quotes]
1:32:53 AM
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Could this be Australia's September the 11th?
Most non-Australians would not know that Kuta beach (and its resorts) is inhabited largely by Australian tourists; and at this time of year, fit young male tourists, because it is a favoured spot for end of season football club tours.
12:59:23 AM
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Saturday, 12 October 2002
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Friday, 11 October 2002
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EDS is coping with tough times with particular reference to the huge contracts it has in Oz. As someone working for the South Australian government I am at their mercy constantly and don't find it a pleasant experience. As Dave says, BOGU (bend over and grease up). I have a very small number of friends in the stratosphere of other government departments who say the EDS contract has been resposible for pulling SA out of the stone age. What do you think?
[Australian IT - Business]
11:30:08 PM
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Thursday, 10 October 2002
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"I have missed more than 9,000 shots in my career. I have lost almost 300 games. On 26 occasions, I have been entrusted to take the game-winning shot and I missed. I have failed over and over again in my life. And that's precisely why I succeed." -Michael Jordan
[Rick@Leaders.net: Quotes]
11:22:45 PM
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Non-technical summary of the Physics Nobel Prize. The 2002 Nobel Prize in Physics has been awarded to three physicists for their work in exotic astronomy. All three published the landmark papers for which the Nobel was awarded in the American Physical Society journal Physical Review Letters.
Neutrino astronomy
Ray Davis and Masatoshi Koshiba win the prize for their work in detecting neutrinos, elusive particles that rarely interact with anything. Trillions of them pass through our bodies every second almost always undisturbed. Neutrinos are the only detectable particle that come from the active energy-producing center of the Sun and are a key to understanding how it works. They also play an important role in many other reactions that occur both on Earth and throughout the universe.
Davis, who did a significant part of his work while based at Brookhaven National Lab, detected neutrinos coming from the nuclear fusion processes that power the Sun. Over 30 years, he was able to detect a mere 2000 neutrinos in 600 tons of cleaning fluid in a tank sitting at the bottom of the Homestake Mine in South Dakota. Many physicists thought this detection was too hard to even attempt but Davis persisted and succeeded. His feat has been compared with finding a single specific grain of sand somewhere in the Sahara desert. (The sign of a neutrino is a single argon atom appearing in the 600 tons of chlorine-based fluid.) The data he collected was the first hard evidence that nuclear processes do occur in the center of the Sun. Davis now lives on Long Island, near Brookhaven Lab. He turns 88 on Monday.
Koshiba, at the University of Tokyo, ran the Kamiokande neutrino detector in a mine in Japan and improved on Davis' experiment because it showed the direction the neutrinos came from and gave results instantly. In February 1987, the Kamiokande detector registered 12 neutrino observations over a 17-minute period. They came from a supernova (an exploding star) in another galaxy. This is actually a huge number of neutrinos compared to the usual number that are detected, so it indicated a particularly violent cosmic event.
X-ray astronomy
Riccardo Giacconi was the first person to discover x-rays hitting the Earth from space. These x-rays are absorbed by the Earth's atmosphere and not detectable at ground level so he sent a rocket up above the atmosphere. He was specifically looking to see if the Moon gave off x-rays after being bombarded with energy from the Sun. He found no evidence for that but as the rocket tumbled through its six-minute flight, he detected a strong burst of x-rays from elsewhere in space. He also discovered a weak background of x-rays coming from all directions. Later, he launched the Uhuru, a satellite specifically designed for looking at these cosmic x-rays. It was followed by the Einstein X-ray Observatory and the Chandra satellite. The field of x-ray astronomy has vastly improved our understanding of the universe and some of its more exotic inhabitants, like black holes. It has also provided some of our most spectacular images of the universe.
More information at the American Physical Society [David Harris: Science news]
2:20:06 PM
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Check out this spectacular sight of a solar flare with the earth shown as a size comparison.
1:47:38 PM
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Nobel Prize in Chemistry. The 2002 Chemistry Nobel Prize is being given "for the development of methods for identification and structure analyses of biological macromolecules" and going to John Fenn and Koichi Tanaka "for their development of soft desorption ionisation methods for mass spectrometric analyses of biological macromolecules" and Kurt Wüthrich "for his development of nuclear magnetic resonance spectroscopy for determining the three-dimensional structure of biological macromolecules in solution".
More details at the Nobel site
[David Harris: Science news]
12:53:25 AM
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Wednesday, 9 October 2002
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"Modern man thinks he loses something -- time -- when he does not do things quickly; yet he does not know what to do with the time he gains -- except kill it."
Erich Fromm (The Art of Loving, 1956) [Rick@Leaders.net: Quotes]
11:58:00 PM
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Nobel Prize in Physics. The Nobel Prize in Physics was announced a few minutes ago as going to experimentalists for the detection of cosmic neutrinos and the discovery of cosmic x-ray sources.
Ray Davis and Masatoshi Koshiba share half the prize for their neutrino studies and Riccardo Giacconi wins the other half for the x-ray work.
Details at the official Nobel site
Some background reading:
Physics Today, August 98, Kamiokande oscillation results
Physics Today, August 01, early SNO results
Physics Today, July 02, later SNO results
Scientific American, Jan 97, RXTE
Physics Today, May 00, x-ray background
Physics Today, Nov 00, Chandra results
Scientific American, May 90, Bahcall, solar nu problem
Scientific American, Aug 99, Kamiokande oscillation results
Physics Today, July 96, SNO
The articles from Physics Today will be available online at some time during the day at http://www.aip.org/pt/
Some relevant websites:
SNO website: http://www.sno.phy.queensu.ca/
US-Kamiokande: http://www.phys.washington.edu/~superk/
Beamline, Winter 99: http://www.slac.stanford.edu/pubs/beamline/pdf/99iii.pdf
Early ref to neutrino oscillation: http://www.aip.org/physnews/preview/1998/neutrino/text.htm
long-baseline oscillation experiments: http://www.hep.anl.gov/ndk/longbnews/
AIP Photo Archive: https://raptor.aip.org/OA_HTML/aipCCtpSctDspRte.jsp?section=10005
Ray Davis history: http://www.bnl.gov/bnlweb/history/neutrino.html
Swedish Academy: http://www.nobel.se/physics/laureates/2002/phyreading.html
Physics Today articles: http://www.physicstoday.org/vol-55/iss-10/nobel.html
APS journal articles: http://www.aps.org/media/
Chandra X-Ray Telescope: http://chandra.harvard.edu/
Kamiokande: http://www-sk.icrr.u-tokyo.ac.jp/index.html
Associated Universities Inc.: http://www.aui.edu/
Ray Davis: The scientist and the man: http://www.sns.ias.edu/~jnb/Papers/Popular/RayDavis/paper.pdf
Photographs of Ray Davis: http://www.sns.ias.edu/~jnb/Papers/Popular/JohnRaypictures/johnraypictures.html
Other awards to the Laureates:
Raymond Davis, 1988 winner of the Tom W. Bonner Prize in Nuclear Physics: http://www.aps.org/praw/bonner/index.html
Raymond Davis, 1992 winner of the W. K. H. Panofsky Prize in Experimental Particle Physics: http://www.aps.org/praw/panofsky/index.html
Masatoshi Koshiba, 2002 winner of the W. K. H. Panofsky Prize in Experimental Particle Physics: http://www.aps.org/praw/panofsky/02winner.html
Original research papers:
--Raymond Davis, Jr--
The first two back-to-back papers showing that neutrinos from the sun should be detectable.
Solar Neutrinos I: Theoretical
John N. Bahcall
Phys. Rev. Lett. 12, 300[^]302 (16 March 1964)
http://link.aps.org/abstract/PRL/v12/p300
Solar Neutrinos II: Experimental
Raymond Davis, Jr.
Phys. Rev. Lett. 12, 303[^]305 (16 March 1964)
http://link.aps.org/abstract/PRL/v12/p303
The first experimental results
Search for Neutrinos from the Sun
Raymond Davis, Jr., Don S. Harmer, and Kenneth C. Hoffman
Phys. Rev. Lett. 20, 1205[^]1209 (20 May 1968)
http://link.aps.org/abstract/PRL/v20/p1205
--Masatoshi Koshiba--
The next generation of neutrino detection experiments
Observation of 8B solar neutrinos in the Kamiokande-II detector
K. S. Hirata, et al.
Phys. Rev. Lett. 63, 16[^]19 (3 July 1989)
http://link.aps.org/abstract/PRL/v63/p16
--Neutrino review papers--
A review of solar neutrino experiments and theory
Solar neutrino experiments: results and implications
Till A. Kirsten
Reviews of Modern Physics, 71, 1213-1232 (July 1999)
http://link.aps.org/abstract/RMP/v71/p1213
A brief history of neutrino physics
Neutrino physics
L. Wolfenstein
Reviews of Modern Physics, 71, S140-S144 (March 1999)
http://link.aps.org/abstract/RMP/v71/pS140
--Riccardo Giacconi--
Evidence for x Rays From Sources Outside the Solar System
Riccardo Giacconi, Herbert Gursky, and Frank R. Paolini
Phys. Rev. Lett. 9, 439[^]443 (1 December, 1962)
http://link.aps.org/abstract/PRL/v9/p439
[David Harris: Science news]
10:11:08 AM
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Nobel Prize in Physiology or Medicine. The 2002 Nobel Prize in Physiology or Medicine to Sydney Brenner, H. Robert Horvitz and John E. Sulston was announced in Stockholm this morning.
The winners were recognised for their work in understanding how genes play a role in determining how organs develop and removing old cells so as to keep organs just the right size.
Although their initial work was all done in the nematode Caenorhabditis elegans, they went on to show that equivalent genes exist in other species, including humans.
More details at the official Nobel site [David Harris: Science news]
10:05:23 AM
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Tuesday, 8 October 2002
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Monday, 7 October 2002
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The Arab satellite TV station al-Jazeera broadcast an audiotape today in which a male voice attributed to Osama bin Laden said the "youths of God" were planning more attacks against the United States.
[Sydney Morning Herald]
12:37:02 PM
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Sunday, 6 October 2002
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"Red Dragon". Anthony Hopkins? Big deal! We've already seen the prequel to "The Silence of the Lambs" and "Hannibal" -- and it was better the first time as Manhunter.
[Salon.com]
10:41:26 AM
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Saturday, 5 October 2002
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Friday, 4 October 2002
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Wednesday, 2 October 2002
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You have to love the many levels of government!
San Francisco Chronicle. From the San Francisco Chronicle:
Two days after Gov. Gray Davis signed a bill legalizing the use of the electric Segway Scooter on California sidewalks, San Francisco Supervisor Chris Daly introduced legislation that would ban the two-wheelers in the city.
[Paul Boutin]
11:29:53 AM
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Theodore Roosevelt. "Far better it is to dare mighty things, to win glorious triumphs even though checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much because they live in the gray twilight that knows neither victory nor defeat."
[Rick@Leaders.net: Quotes]
10:58:49 AM
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Oh yeah!
"My problem is reconciling my net income with my gross habits." -Erroll Flynn
[Rick@Leaders.net: Quotes]
3:28:20 AM
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© Copyright 2005 Peter Nixon.
Last update: 27/9/05; 8:51:30 PM.
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