31 Mar 2010 at 10:50
Since I needed to look these up, decided to put them where I can find them.
When using AJAX and POST, need to put the normal posted content into a file, test.txt in this case and then send the data to the server using either curl (for one off checking the result) and apache bench (too see how fast it can respond)
curl -d @test.txt http://local.site.com/ajax/post/url
ab -p test.txt -T “application/x-www-form-urlencoded” -H “X-Requested-With: XMLHttpRequest” -c 1 -n 10
For ab, c is for concurrency, n is for number of requests. Need to check the expected document response length to be sure that are not getting back a 200 with the wrong values. T sets the content type, H adds headers to the HTTP request.
14 Mar 2010 at 14:52
Interesting ideas in a PDF presentation on climate change. It is amazing what difference we have created in moving from 285ppm of CO2 in the atmosphere to the present 390ppm. One disturbing idea is that the temperature effects have so far been buffered by warming the ocean and melting lots of ice in glaciers. Since a lot of places rely on glaciers to feed rivers during the summer, before the glaciers melt entirely we need to be building a whole lot more storage capacity in our reservoirs or many places are going to experience extremely severe water shortages in the summer months.
“We basically have three choices: mitigation, adaptation and suffering. We’re going to do some of each. The question is what the mix is going to be. The more mitigation we do, the less adaptation will be required and the less suffering there will be.” – John Holdren
Source - page 68
Other sources for teh science background to this http://realclimate.org and http://climateprogress.org/.
12 Mar 2010 at 18:58
Economics for the rest of us is a very interesting comparison of classical vs neo-classical economics with the central tenet that economics as taught an promoted is
Arguably, the damage from the teaching of economist’s theory of wages is far greater than the damage from the teaching of creationism. Yet the theory of wages is part of economics education in any and all schools, and it continues without any notice or apposition. The reason is, of course, not hard to understand. While everyone is hurt when we teach religion and pretend it’s science, not everyone is hurt when we teach economics. What workers lose, executives and capitalists gain; and it is the latter who study economics, hire economists, and endow schools.
Lots of lessons in the book for the current economic meltdown, not least that the failure of governments to ensure equality and equitable distribution of wealth has and will make society a lot worse off even if the “economy” looks to be healthy.
The most interesting claim is that unemployment results when spending on consumption and investment goods declines. Investment is needed to absorb the surplus that is created, and without this investment in real goods, productivity gains result in lost jobs. In addition, once consumer confidence drops, people stop buying and then the downward spiral starts. But contrary to current popularized ideas, it is not the consumers who can spend our way out of the recession. Consumers are rationally saving money in case things go worse. It is the investors who have to show the confidence by investing in new productive capacity, that will generate the jobs that enable consumers to feel confident again.
The executives and capitalists who have so far managed to retain too large a share of the overall pie are now hoarding cash, not investing in productive capacity and as a result are deepening the depression. After all, is capital not supposed to be the patient partner in the enterprise. Why should anyone expect a family with a large mortgage to spend money when billionaires and large enterprises have cash stored away in banks, looking for lucrative investment opportunities but only bothering to invest when they have a near certainty of return.
02 Mar 2010 at 20:25
Yes, there is a fancy name for simpler explanations - Occam’s Razor - or Ockham if you prefer the old spelling, but I prefer to use plain english.
A common problem with beginners to software development is that when an error occurs, they manage to convince themselves that they have found an error in the compiler or computer. Yes, sometimes this is actually happens, compilers do have errors, but a much simpler, and more likely explanation is that they have made a normal beginner mistake in their code. Of the two, it makes more sense to investigate the simpler cause first and only then, if no problems can be found is it worth while investigating alternate explanations. Most of the time the simple explanation is the one to go with. If a program suddenly starts failing, and there have been some recent edits to the code, then the simplest explanation is that the error was surfaced by the changes, so that is the best place to start looking.
Climate science as a good example of simpler explanations
One explanation of the problem of climate change and rising CO2 levels is that there has been a conspiracy of scientists to raise the specter of anthropogenic global warming so that they get fame and fortune.
A simpler explanation is that the conspiracy is n the other side. That some large corporations with vested interests are leading a campaign to convince the general public that there is nothing strange going on with the climate.
One way of testing which of these is a more likely explanation is to look at past behavior. Can we find any evidence of scientists acting in concert to deceive anyone? No, sorry, nothing there. Sure there have been cases where an individual scientist or group of scientists have been enthusiastic about an idea that turned out to be incorrect, but these cases have never lasted for long and even early on there was the normal skepticism of scientists asking questions.
Looking to the other side, can we find any evidence of corporations acting in concert to deceive people? Yes, several times, often with significant deleterious effects on people and the environment. Car and oil companies managed to keep lead in petrol for a long time after the effects of low level of lead exposure were known to harm humans. Lead was only removed when catalytic converters were required to reduce smog and the lead was poisoning the catalytic converters.
Another example, early on the car companies bought up and dismantled many of the electric trolley companies thus forcing people to buy cars in order to get around in cities. Very few cities have effective light rail transit these days, even though in the 1930’s most major cities had these electric trolley lines. San Francisco is one of the few cities that still has the remnants of the old system still running.
Another example is the tobacco industry, managing to spread enough doubt about the effects of smoking so that for over forty years there was insufficient effort put into preventing people from becoming addicted to the nicotine in cigarettes. End result of this was a massive lawsuit and damages awarded against the industry, but even now, the public attitude is such that the tobacco companies can still sell very addictive substances and keep on addicting new generations of customers (aka addicts).
With these examples, the simplest explanation of the public debate over global warming is that there is a conspiracy among the major corporations who have a vested interest in the Coal and Oil sectors of industry to spread doubt and uncertainty. Very year the doubt proceeds, the corporations generate billions in profit. Following the money is always a simpler explanation.