## Search found 35 matches

- Thu May 19, 2011 7:03 am UTC
- Forum: Mathematics
- Topic: If you learned statistics would you never buy insurance?
- Replies:
**92** - Views:
**10369**

### Re: If you learned statistics would you never buy insurance?

@OP: This issue is very well studied. See, e.g. http://www.gametheory.net/mike/applets/Risk/ . It comes down to: if you're risk averse, buy insurance. How much should you pay for insurance, optimally? Exactly the amount at which you would be just indifferent between paying the insurance or taking th...

- Thu Jan 20, 2011 2:49 pm UTC
- Forum: Mathematics
- Topic: doubly stochastic markov matrices
- Replies:
**1** - Views:
**811**

### doubly stochastic markov matrices

I must be missing something simple here ... but I can't figure out the proofs that a doubly stochastic matrix has fixed points with the uniform distribution. Most of the proofs I've seen invoke the fact that [1,...,1] is clearly fixed under multiplication by the stochastic matrix P. Scale it and we'...

- Mon Jun 14, 2010 2:00 pm UTC
- Forum: Science
- Topic: Find the paper with the coolest title.
- Replies:
**11** - Views:
**2564**

### Re: Find the paper with the coolest title.

On my lab's 'Wall of Shame'

'Origin and maintenance of sex: the evolutionary joys of self sex'

'The role of sexual intercourse in the etiology of carpal tunnel syndrome'

'Apparent Size of Holes felt with the Tongue'

Nature 1964.

'Origin and maintenance of sex: the evolutionary joys of self sex'

'The role of sexual intercourse in the etiology of carpal tunnel syndrome'

'Apparent Size of Holes felt with the Tongue'

Nature 1964.

- Tue Jan 12, 2010 3:31 am UTC
- Forum: Science
- Topic: Modern einsteins
- Replies:
**92** - Views:
**9967**

### Re: Modern einsteins

In physics, I would say no one since Einstein is an Einstein.

The problem is that with fields which are mostly experimental, there's less of a chance to tie everything together with a nice theory like Einstein did.

The problem is that with fields which are mostly experimental, there's less of a chance to tie everything together with a nice theory like Einstein did.

- Fri Dec 18, 2009 7:27 am UTC
- Forum: Science
- Topic: Quantum Conciousness
- Replies:
**18** - Views:
**2289**

### Re: Quantum Conciousness

So the body does use quantum processes to enhance some 'computations' in normal cells, like in the electron transport chain.

It seems reasonable to me that quantum processes are used to some extent in the brain, but I don't think that they're used as Penrose claims.

It seems reasonable to me that quantum processes are used to some extent in the brain, but I don't think that they're used as Penrose claims.

- Fri Dec 11, 2009 11:19 am UTC
- Forum: Mathematics
- Topic: Matrices and how they transform graphs
- Replies:
**28** - Views:
**2793**

### Re: Matrices and how they transform graphs

Nice Mungo! One of the coolest things about matrices is that you can multiply them together to get a new matrix. What other things have this property that we can "multiply" them and still get an object of the same kind (like multiplying numbers)? How would we write this property down? If s...

- Wed Dec 09, 2009 12:23 am UTC
- Forum: Science
- Topic: Why do we torture ourselves with Minkowski metric?
- Replies:
**36** - Views:
**5785**

### Re: Why do we torture ourselves with Minkowski metric?

The thing I find most useful about the Minkowski metric is the direct comparison to GR: It's easy to see that Minkowski space is flat just by looking at the metric. Then when we move to GR, we can see why the new metric induced from the equivalence principle makes it curved, and compare the two. Thi...

- Sat Dec 05, 2009 4:57 pm UTC
- Forum: News & Articles
- Topic: Amanda Knox Trial
- Replies:
**55** - Views:
**8174**

### Amanda Knox Trial

Below I'm not at all implying that Amanda Knox or her boyfriend are in particular innocent. I'm just questioning the use of evidence and general methods by the prosecution. I'm not so much interested in 'do you think she's guilty/innocent?' but the means of trying suspects in court. That is, I'm not...

- Wed Dec 02, 2009 9:37 am UTC
- Forum: Science
- Topic: Auditory hallucination before falling asleep
- Replies:
**13** - Views:
**18389**

### Re: Auditory hallucination before falling asleep

I get this sometimes when I'm about to sleep or wake up, but when I do, it's like I can hear an entire song in my head, all of the notes, etc. at once, (which is something I can't do while totally awake)

- Tue Dec 01, 2009 2:46 am UTC
- Forum: Mathematics
- Topic: Wrong on the Internet: John Gabriel
- Replies:
**185** - Views:
**65495**

### Re: Internet Crazy Person: John Gabriel

I guess I think this situation is kind of sad, similar, though I could never make a diagnosis, to general non-paranoid schizophrenia. Unfortunately, logical questions won't work in this case, just like your average internet crazy person; they really are convinced they're correct, and can't see past ...

- Mon Nov 30, 2009 8:58 am UTC
- Forum: Mathematics
- Topic: I think I proved Fermat's Last Theorem
- Replies:
**44** - Views:
**6944**

### Re: I think I proved Fermat's Last Theorem

Ten Signs A Mathematical Breakthrough is Wrong (from Terence Tao's website (to Aaronson's blog)) In particular: 6. The paper jumps into technicalities without presenting a new idea. If a famous problem could be solved only by manipulating formulas and applying standard reductions, then it’s overwhe...

- Sat Nov 21, 2009 9:50 pm UTC
- Forum: Science
- Topic: Microwaving food - hazardous or not?
- Replies:
**45** - Views:
**4875**

### Re: Microwaving food - hazardous or not?

about the coolest thing you can do with a microwave is put a lightbulb inside. http://www.youtube.com/watch?v=8XQZW9NTQAY

- Thu Nov 12, 2009 6:20 am UTC
- Forum: Science
- Topic: Nipple Size (deadly serious)
- Replies:
**20** - Views:
**5321**

### Re: Nipple Size (deadly serious)

Plasmic-Turtle wrote: Half-dollars sound rather large for nipples themselves?

- Tue Nov 10, 2009 7:19 am UTC
- Forum: Science
- Topic: Nipple Size (deadly serious)
- Replies:
**20** - Views:
**5321**

### Re: Nipple Size (deadly serious)

I read, either in discover or Scientific American about a group of material scientists that are paid to watch scantily clad women run around. They are designing better sports bras. Unfortunately this probably decreases their ability to get it up dramatically. Then again, if it takes a lot to get it...

- Mon Nov 09, 2009 5:59 pm UTC
- Forum: Science
- Topic: Mathematics and Biology
- Replies:
**46** - Views:
**4222**

### Re: Mathematics and Biology

I think there are two definitions of "succeed" that people are using here, and asking about the necessecity of math to succeed in biology with respect to one of those definitions. 1) To be a respected biologist who is well published, funded, etc. (i.e. a graduate of a top honors biology pr...

- Sun Nov 08, 2009 6:27 pm UTC
- Forum: Mathematics
- Topic: Mobius Strip <--> Berlin Wall . ..
- Replies:
**2** - Views:
**920**

### Mobius Strip <--> Berlin Wall . ..

From a poem on the fall of the Berlin Wall: It was a weird wall. Like the Mobius strip, it had only one side, the other was unseen: far side of the Moon. -Vera Pavlova Translated by Steven Seymour from the Russian Full poem at http://www.nytimes.com/interactive/2009/11/08/opinion/08berlinpoems.html?...

- Sun Nov 08, 2009 4:25 am UTC
- Forum: Science
- Topic: Lorentz Transformations - where do they come from?
- Replies:
**2** - Views:
**612**

### Lorentz Transformations - where do they come from?

I understand that Lorentz Transformations invariant under coordinate transformations between inertial frames. This is straightforward to show, and it is also relatively straightforward to show that holding the speed of light constant forces this. What I don't understand is how this was 'obvious' to ...

- Sat Nov 07, 2009 8:49 pm UTC
- Forum: Science
- Topic: Mathematics and Biology
- Replies:
**46** - Views:
**4222**

### Re: Mathematics and Biology

Good point.

- Fri Nov 06, 2009 8:17 am UTC
- Forum: Science
- Topic: Mathematics and Biology
- Replies:
**46** - Views:
**4222**

### Re: Mathematics and Biology

@izawwlgood When you say : I haven't read a paper in the last 2 years that didn't have an engineer, programmer, or physicist as a collaborator. You're saying "math is important to every paper I've read in the last 2 years." My point was actually less strong than what you seem to say above....

- Fri Nov 06, 2009 5:36 am UTC
- Forum: Science
- Topic: Mathematics and Biology
- Replies:
**46** - Views:
**4222**

### Re: Mathematics and Biology

When doing statistical tests, you need to know what type of variables a test can be used for, whether or not your data breaks assumptions of normality and equal variance, and other such things. These are in fact quite important to using statistics properly. But do you need to know how to calculate ...

- Thu Nov 05, 2009 3:42 am UTC
- Forum: Science
- Topic: Mathematics and Biology
- Replies:
**46** - Views:
**4222**

### Re: Mathematics and Biology

statistics in biology is like having a car. To drive it you don't have to know the inner workings; to use statistical tests and interpret their results, you don't have to know how to do the calculations and do any actual math. AGHGHGHGHGHGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHh Statistics are misa...

- Mon Oct 26, 2009 7:15 am UTC
- Forum: Science
- Topic: I want to learn particle and quantum physics.
- Replies:
**30** - Views:
**4596**

### Re: I want to learn particle and quantum physics.

I recommend "The Road to Reality" by Roger Penrose, especially if you have an extensive prior background in math. It goes a little beyond just particle and quantum physics, but: It has excellent references It cross-references other sections quite well. It's made for people who like math, t...

- Thu Oct 15, 2009 1:56 am UTC
- Forum: Mathematics
- Topic: Has Fermats Last Theorem been solved?
- Replies:
**25** - Views:
**4448**

### Re: Has Fermats Last Theorem been solved?

albeit a small one Even then, it took a whole year to fix. Many theorems take a long time to hash out. Look at the proof of the Poincare conjecture. It took a few years before it was generally accepted that it was correct. Part of it, though, is that for any given subdiscipline of maths, there are ...

- Tue Sep 15, 2009 6:37 am UTC
- Forum: Science
- Topic: A question on the nature of Physics
- Replies:
**9** - Views:
**1551**

### Re: A question on the nature of Physics

Part of the problem with being "not very skilled with math" might be saying things like that. Obviously people have limits, but if you're good with geometry but not, say, algebra, it might just be your approach. I once knew a guy who thought he was bad at math until junior year in HS, when...

- Fri Sep 11, 2009 9:44 am UTC
- Forum: Science
- Topic: Are transfinite mathematics useful in science?
- Replies:
**61** - Views:
**5074**

### Re: Are transfinite mathematics useful in science?

A quick browse through my physics books and wikipedia gave a few theories/procedures that seem rest on and/or be made much more useful by transfinite math, or "actual" infinity: Path integrals in quantum field theory require integrating over the infinite-dimensional space of paths in space...

- Mon Sep 07, 2009 11:59 pm UTC
- Forum: Mathematics
- Topic: Mathematical limits for computer programs
- Replies:
**59** - Views:
**5087**

### Re: Mathematical limits for computer programs

Penrose also thinks that it would work differently than the 'traditional' quantum computer so that it could do more things. . . though he does say this would need a new approach to qm.

- Sun Sep 06, 2009 10:45 pm UTC
- Forum: Mathematics
- Topic: The Road To Reality, by Roger Penrose
- Replies:
**9** - Views:
**2264**

### Re: The Road To Reality, by Roger Penrose

I picked it up a bit ago, about 200 pages in. It's definitely not a self-contained book if you want to understand everything on the first go, but it is a great companion, in the sense that most math texts are pretty dry and don't mention much in the way of motivation for certain definitions, for ins...

- Sun Sep 06, 2009 10:24 pm UTC
- Forum: Mathematics
- Topic: Mathematical limits for computer programs
- Replies:
**59** - Views:
**5087**

### Re: Mathematical limits for computer programs

Yeah, after reading the link to a discussion of the proof by Feferman (apparently a logician at Stanford) I get the sense that Penrose kind of breezed through the argument. However, although I've had to prove Godel's theorem on a final, I'm nowhere near qualified to reject Penrose's argument. (On di...

- Sun Sep 06, 2009 4:37 am UTC
- Forum: Mathematics
- Topic: Mathematical limits for computer programs
- Replies:
**59** - Views:
**5087**

### Re: Mathematical limits for computer programs

The question boils down to whether or not the brain has some physical capacity not available to "computers." Any general notion of algorithm that is equivalent to a Turing Machine has some basic properties, like unlimited memory, finite description, the inability to do an infinite amount o...

- Fri May 29, 2009 4:48 am UTC
- Forum: Science
- Topic: What is the hottest possible temperature?
- Replies:
**28** - Views:
**13938**

### Re: What is the hottest possible temperature?

When I enter a room.

- Wed May 27, 2009 7:03 am UTC
- Forum: Science
- Topic: Properties of Sentience
- Replies:
**28** - Views:
**3742**

### Re: Properties of Sentience

@ rockoTDF: I agree that we can plausibly say that the monkey that touches the dot on its forehead while looking in the mirror is self-aware. But that doesn't give a general criterion other than to consider that we do similar things and we do them because we are self-aware. OP asked: "Without b...

- Tue May 26, 2009 4:48 pm UTC
- Forum: Science
- Topic: Properties of Sentience
- Replies:
**28** - Views:
**3742**

### Re: Properties of Sentience

I think there are two ways to look at this. From a behavioral standpoint, can we observe something and decide if it is sentient? Unfortunately, drawing an analogy from Rice's Theorem, even if we did define a binary property S of being sentient, there would be no algorithm to decide if a given being ...

- Tue May 26, 2009 4:09 pm UTC
- Forum: Science
- Topic: Self replicating machines
- Replies:
**26** - Views:
**3432**

### Re: Self replicating machines

I think that self replicating machines that can merely follow a set of instructions to recreate themselves are not so interesting as machines that can obtain their own description, and then proceed to replicate based on that information.

- Tue May 26, 2009 3:59 pm UTC
- Forum: Science
- Topic: invariance of lagrangian
- Replies:
**3** - Views:
**662**

### Re: invariance of lagrangian

yeah once I went back to the variational derivation it made good sense. The problem I was reviewing asked us to show that it followed from the same line as D'Alembert's principle. Still can't see it from that standpoint.

- Tue May 26, 2009 4:46 am UTC
- Forum: Science
- Topic: invariance of lagrangian
- Replies:
**3** - Views:
**662**

### invariance of lagrangian

Not homework, just studying for final.

I am confused by why lagrange's equations still work when we add the time derivative of an arbitrary differentiable function of the generalized coordinates and time, i.e. if L is a suitable lagrangian for our system, why is L' = L + dF/dt also suitable?

I am confused by why lagrange's equations still work when we add the time derivative of an arbitrary differentiable function of the generalized coordinates and time, i.e. if L is a suitable lagrangian for our system, why is L' = L + dF/dt also suitable?