Cloaking uses metamaterials which have a negative refractive index- these bend light rays around the object being cloaked. Very recently, physicists and engineers realised that a similar principle can be applied to pressure waves caused by earthquakes. With the right design, the shockwaves might be bent around a building, rendering it "invisible" to an earthquake.
Dave Foster Wallace's fantastic book "Infinite Jest" touched on this idea. Here's an excerpt from the book:
Good old traditional audio-only phone conversations allowed you to presume that the person on the other end was paying complete attention to you while also permitting you not to have to pay anything even close to complete attention to her. A traditional aural-only conversation [...] let you enter a kind of highway-hypnotic semi-attentive fugue: while conversing, you could look around the room, doodle, fine-groom, peel tiny bits of dead skin away from your cuticles, compose phone-pad haiku, stir things on the stove; you could even carry on a whole separate additional sign-language-and-exaggerated-facial-expression type of conversation with people right there in the room with you, all while seeming to be right there attending closely to the voice on the phone. And yet — and this was the retrospectively marvelous part — even as you were dividing your attention between the phone call and all sorts of other idle little fuguelike activities, you were somehow never haunted by the suspicion that the person on the other end’s attention might be similarly divided.
[...] Video telephony rendered the fantasy insupportable. Callers now found they had to compose the same sort of earnest, slightly overintense listener’s expression they had to compose for in-person exchanges. Those caller who out of unconscious habit succumbed to fuguelike doodling or pants-crease-adjustment now came off looking extra rude, absentminded, or childishly self-absorbed. Callers who even more unconsciously blemish-scanned or nostril explored looked up to find horrified expressions.
I'm not sure the distinction you are using. Quants predict nothing. They are used to see which companies appear undervalued, and thus would be good values (and not in the sense of a value vs growth company). They are also used to determine which appear overpriced.
I think that's more like a financial analyst. A quant typically works one level of abstraction away from the stock market itself, calculating prices and hedging strategies for stock options or credit default swaps, say.
I know there's a lot of anti-quant sentiment around at the moment, and this being slashdot, I'd like to add a disclaimer: I'm just trying to describe the job that a quant does in theory. I'm not making any statement about whether the methods they use at present are effective. Please keep that in mind before flaming me.
For the record, quants rarely try to predict things in the market. That's left to people who work in econometrics. The main job that a quant does is to price financial instruments in a way that is consistent with the market prices of other liquidly traded assets. I'm being deliberately vague about what precisely is meant by "consistent" because that often depends on the choice of model, but there are also model-free results which require certain asset prices to obey certain relations: put-call parity, for example.
4. You can force SSL for all communication with their site.
It seems that https://www.google.com/ is in beta testing phase and works now. I immediately changed my homepage when I found it. This may be old news, but I missed any announcements about it. I know SSL has been implemented in gmail for a while.
The only part of your post that I'm objecting to is "people don't understand the scientific method". What I'm trying to argue is that both sides had good science.
Again what's your point? How does this justify banning books describing the theory that eventually proved to be correct?
So how were the church to know that the theory would eventually be proven correct? All they saw was some upstart trying to make fools out of them. Remember, this was one of the most powerful organisations on earth. You didn't mess with the church in Galileo's time the same way you didn't mess with senator McCarthy in his day. Right or wrong, that's the way it was.
I was talking about the scientific method if you bother to read what I actually wrote instead of launching into a tirade about how your pet relgious body did no wrong.
Yuo weren't talking about the scientific method, you were condemning Galileo's treateatment by the church. I actually did address the scientific method.
Precisely. Mathematical Brownian motion has a *wonderful* property known as infinite variation. This means that if you took an accurate plot of Brownian motion over a finite time interval, say the interval [0,1], and tried to measure the length of the curve, you would find that it is infinite. You can take one "piece" of Brownian motion and stretch it out the whole way across the universe.
If a particle was moving according to mathematical Brownian motion, its velocity would be infinite, which is clearly impossible. The construction provides a very good approximation to random movements at small scales, though.
They were justified to some extent. The geocentric theory based on epicycles had predictive power too: it could be used to predict eclipses to a reasonable accuracy. The heliocentric model explained the retrograde motion of planets, but also made predictions about parallax of heavenly bodies, which was not observed (since the measurements available at the time were not sensitive enough).
Bot theories had merit, and given the information available at the time, neither was perfect. That doesn't excuse the church from supressing the ideas, but it's naive to argue along the lines of "Galileo was right and the church was wrong". Galileo just didn't play the politics right.
You should read up on the blasphemy law. It was introduced in such a way that no-one could be prosecuted under it. Formerly, there was a legal grey area in which someone might actually have been punished under the law as it stood. The alternative was a referendum to change the constitution, and the issue wasn''t really important enough to justify one. The minister for justice has stated that next time there is a referendum, this will be decided properly.
The principle is correct, but you're failing to take into account the probability of an the respective events. Given that winning 60% of the vote is considered a landslide, you can think of asking someone whether they're voting Republican or Democrat as a coin flip with a small bias in one way or the other. Because the race is so close, a few extra republicans or democrats in your sample won't produce a huge error in your estimate.
On the other hand, a brain tumor can be thought of as a rare event. If the true incidence rate of brain cancer is five occurrences per thousand people over ten years, and your sample of 1,000 people has six incidences, you have a sample error of 20%. It's because of this that a small variation in the numbers can produce a large error. Therefore if you want to accurately assess the rate of cancer, you need a much bigger sample size.
Most of the issues addressed in the summary actually result from the fact that top US universities are insanely expensive. Harvard is about thirty thousand dollars for an undergraduate degree whereas Cambridge is about three thousand Stirling.
Perhaps you meant monotonically decreasing nonnegative function on the nonnegative reals with f(0) = 0, or something to that effect...
As I'm sure you can tell, I'm a big hit at parties.
Re:If you can't handle calculus, science isnt for
on
Help Me Get My Math Back?
·
· Score: 4, Insightful
Parts of biology are getting insanely mathematical. Very recently, say the last five to ten years, there has been a large influx of mathematicians into biology. They use stochastic analysis to model various processes such as transmission of genes to offspring and growth of cell populations.
A decent fraction of the PhD students in my department (maths) are involved in biology.
Topologically, the torus can be identified with something called S1xS1 (the cartesian product of two "one-spheres", aka circles). Likewise, the n-dimensional torus is the cartesian product of n copies of the circle.
This means that the one-dimenstional torus is just the plain old circle. In one dimension, the torus and sphere are the same thing.
There's a big fat gap between what the calculations say the rate of galaxy formation should be, and what it is actually observed to be. This new observation accounts for 90% of that rate.
Well, it's still an unsolved problem as to whether Pi is "random" (that is, whether it's a Normal number in base 10. Even if it is, it may not be normal in another base.
Slashdot Mirror
Cloaking uses metamaterials which have a negative refractive index- these bend light rays around the object being cloaked. Very recently, physicists and engineers realised that a similar principle can be applied to pressure waves caused by earthquakes. With the right design, the shockwaves might be bent around a building, rendering it "invisible" to an earthquake.
This was previously thought impossible due to mistakes in some engineering research articles.
Link here:
http://www.sciencedaily.com/releases/2009/07/090720105125.htm
More techncial articles can be found by googling "elastic cloaking".
Precisely. In your example, without conditioning on the fact that there is one boy, the possibilities are:
BB BG GB GG.
with a uniform distribution on each outcome. Once you condition on at least one boy, GG is removed, and you are left with three equally likely events.
Dave Foster Wallace's fantastic book "Infinite Jest" touched on this idea. Here's an excerpt from the book:
Good old traditional audio-only phone conversations allowed you to presume that the person on the other end was paying complete attention to you while also permitting you not to have to pay anything even close to complete attention to her. A traditional aural-only conversation [...] let you enter a kind of highway-hypnotic semi-attentive fugue: while conversing, you could look around the room, doodle, fine-groom, peel tiny bits of dead skin away from your cuticles, compose phone-pad haiku, stir things on the stove; you could even carry on a whole separate additional sign-language-and-exaggerated-facial-expression type of conversation with people right there in the room with you, all while seeming to be right there attending closely to the voice on the phone. And yet — and this was the retrospectively marvelous part — even as you were dividing your attention between the phone call and all sorts of other idle little fuguelike activities, you were somehow never haunted by the suspicion that the person on the other end’s attention might be similarly divided.
[...] Video telephony rendered the fantasy insupportable. Callers now found they had to compose the same sort of earnest, slightly overintense listener’s expression they had to compose for in-person exchanges. Those caller who out of unconscious habit succumbed to fuguelike doodling or pants-crease-adjustment now came off looking extra rude, absentminded, or childishly self-absorbed. Callers who even more unconsciously blemish-scanned or nostril explored looked up to find horrified expressions.
"it's quite possible that Sir Terry saw it too. - although he probably doesn't remember"
Pratchett has Alzheimer's disease.
Tasteless.
I'm not sure the distinction you are using. Quants predict nothing. They are used to see which companies appear undervalued, and thus would be good values (and not in the sense of a value vs growth company). They are also used to determine which appear overpriced.
I think that's more like a financial analyst. A quant typically works one level of abstraction away from the stock market itself, calculating prices and hedging strategies for stock options or credit default swaps, say.
I know there's a lot of anti-quant sentiment around at the moment, and this being slashdot, I'd like to add a disclaimer: I'm just trying to describe the job that a quant does in theory. I'm not making any statement about whether the methods they use at present are effective. Please keep that in mind before flaming me.
For the record, quants rarely try to predict things in the market. That's left to people who work in econometrics. The main job that a quant does is to price financial instruments in a way that is consistent with the market prices of other liquidly traded assets. I'm being deliberately vague about what precisely is meant by "consistent" because that often depends on the choice of model, but there are also model-free results which require certain asset prices to obey certain relations: put-call parity, for example.
Judging by how badly the site got hacked within five minutes of being linked to Slashdot, I'd say people are playing with it enough already.
4. You can force SSL for all communication with their site.
It seems that https://www.google.com/ is in beta testing phase and works now. I immediately changed my homepage when I found it. This may be old news, but I missed any announcements about it. I know SSL has been implemented in gmail for a while.
There was this kid named Ix who apparently knew, but we could never get a satisfactory explanation out of him.
The only part of your post that I'm objecting to is "people don't understand the scientific method". What I'm trying to argue is that both sides had good science.
Again what's your point? How does this justify banning books describing the theory that eventually proved to be correct?
So how were the church to know that the theory would eventually be proven correct? All they saw was some upstart trying to make fools out of them. Remember, this was one of the most powerful organisations on earth. You didn't mess with the church in Galileo's time the same way you didn't mess with senator McCarthy in his day. Right or wrong, that's the way it was.
I was talking about the scientific method if you bother to read what I actually wrote instead of launching into a tirade about how your pet relgious body did no wrong.
Yuo weren't talking about the scientific method, you were condemning Galileo's treateatment by the church. I actually did address the scientific method.
Precisely. Mathematical Brownian motion has a *wonderful* property known as infinite variation. This means that if you took an accurate plot of Brownian motion over a finite time interval, say the interval [0,1], and tried to measure the length of the curve, you would find that it is infinite. You can take one "piece" of Brownian motion and stretch it out the whole way across the universe.
If a particle was moving according to mathematical Brownian motion, its velocity would be infinite, which is clearly impossible. The construction provides a very good approximation to random movements at small scales, though.
They were justified to some extent. The geocentric theory based on epicycles had predictive power too: it could be used to predict eclipses to a reasonable accuracy. The heliocentric model explained the retrograde motion of planets, but also made predictions about parallax of heavenly bodies, which was not observed (since the measurements available at the time were not sensitive enough).
Bot theories had merit, and given the information available at the time, neither was perfect. That doesn't excuse the church from supressing the ideas, but it's naive to argue along the lines of "Galileo was right and the church was wrong". Galileo just didn't play the politics right.
You should read up on the blasphemy law. It was introduced in such a way that no-one could be prosecuted under it. Formerly, there was a legal grey area in which someone might actually have been punished under the law as it stood. The alternative was a referendum to change the constitution, and the issue wasn''t really important enough to justify one. The minister for justice has stated that next time there is a referendum, this will be decided properly.
According to this, she laughed and asked him for a copy when he showed it to her. Sounds like there's some sort of personal vendetta going on here.
http://felidware.com/DylanEvans/ifut.pdf
The principle is correct, but you're failing to take into account the probability of an the respective events. Given that winning 60% of the vote is considered a landslide, you can think of asking someone whether they're voting Republican or Democrat as a coin flip with a small bias in one way or the other. Because the race is so close, a few extra republicans or democrats in your sample won't produce a huge error in your estimate.
On the other hand, a brain tumor can be thought of as a rare event. If the true incidence rate of brain cancer is five occurrences per thousand people over ten years, and your sample of 1,000 people has six incidences, you have a sample error of 20%. It's because of this that a small variation in the numbers can produce a large error. Therefore if you want to accurately assess the rate of cancer, you need a much bigger sample size.
I meant per annum for both universities. Should have mentioned that.
Most of the issues addressed in the summary actually result from the fact that top US universities are insanely expensive. Harvard is about thirty thousand dollars for an undergraduate degree whereas Cambridge is about three thousand Stirling.
f(x) = x satisfies that condition.
Perhaps you meant monotonically decreasing nonnegative function on the nonnegative reals with f(0) = 0, or something to that effect...
As I'm sure you can tell, I'm a big hit at parties.
Parts of biology are getting insanely mathematical. Very recently, say the last five to ten years, there has been a large influx of mathematicians into biology. They use stochastic analysis to model various processes such as transmission of genes to offspring and growth of cell populations.
A decent fraction of the PhD students in my department (maths) are involved in biology.
Topologically, the torus can be identified with something called S1xS1 (the cartesian product of two "one-spheres", aka circles).
Likewise, the n-dimensional torus is the cartesian product of n copies of the circle.
This means that the one-dimenstional torus is just the plain old circle. In one dimension, the torus and sphere are the same thing.
There's a big fat gap between what the calculations say the rate of galaxy formation should be, and what it is actually observed to be. This new observation accounts for 90% of that rate.
Bah. Wake me up when they have a maneuverable superluminal cruise missile.
Yepanopticons it is
Well, it's still an unsolved problem as to whether Pi is "random" (that is, whether it's a Normal number in base 10. Even if it is, it may not be normal in another base.