Great idea, this mechanical turk thing, but I think the example you gave shows its limitation if none of them objected even to the first item in your list:
1. Government should ban smoking by people under 18, because of the harmful health effects.
It's not because of the harmful effects, it's because people under 18 are not considered legally responsible for their actions. Yeah, there may be exceptions and inconsistencies to that (can't buy alcohol until you're 21, but you can die in a war at age 18, for instance), but that's the reason.
Anyway, you need at least one Turk that responds to each of your presumptions.
FYI, the Department of Redundancy Department (DRD Department) is conveniently located within the Department of of Superfluous Redundancies and Tautological Pleonasms Department (DSRTPD Department).
You're "in the field," eh? Are you an EE? You learn this stuff in a senior level comm class.
The "noise floor" (actually noise power spectral density) is determined by kT, Boltzmann constant times Kelvin temperature.
Looking into empty space, the noise temperature is the magical 3 K. As far as the receiver noise floor, astronomical receivers are typically cryogenically cooled just to reduce the noise floor. So, assuming receiver noise is lower than space noise, the noise PSD is -193.8 dBm/Hz.
And bandwidth? Depends on how fast/slow the message is. Add 10log(BW) to the noise PSD and THAT'S your noise floor.
Anyway, the link budget *is* difficult, but not impossible. It does require a certain amount of the other civilization actually *wanting* to be found, though.
Apparently, the laser can be used for a variety of things without actually being the prime mover. Still, since there's no description of "photonic laser" propulsion, I'm not clear on how the laser is doing anything.
It matters. Actually, what matters more is the actual exposure time vs. field of view. Just like in regular cameras, the higher the magnification (higher zoom), the narrower the field of view and the more sensitive the image will be to any motion during exposure.
For planetary images, you can do pretty well with short exposures and using align/stack software. By short, I mean 1/30 to 1/2 second. This will get you pictures of Mercury, Venus, Mars, Jupiter and Saturn.
For deep-sky stuff, you need to have much longer exposures, and you will often want a narrow field of view. For this, you will definitely need accurate RA tracking and a very accurate polar alignment. I have worked with up to 30 second exposures; this takes quite a bit of patience with a manual polar alignment.
Really wide field photos with a digital camera and no telescope is a lot easier to do, but most regular digital cameras aren't that sensitive (lots of noise in long exposures).
The equipment I have: 6" Matsukov-Cassegrain, Meade DSI color camera, plus an $800 mount (I forget the brand). This ran about $2.4K total.
I guess my main point would be that astophotography requires quite a bit of patience, and does not produce the kind of pictures you see in magazines without a lot of extra work and a lot of really expensive equipment. I didn't start out on this path right away and wouldn't recommend it unless you have a lot of money to spend.
Another way to look at it is everything I say here is wrong if you throw enough money at it!
Off topic, but heck, I get a lot of interesting info from off topic posts...
Hydrogen, helium and a tiny bit of lithium existed after the big bang. *Everything* heaver was created in the core of stars, or as a decay product of something produced in a star core. The reference to iron is a relevant, but not as the poster intended. Fusion of light elements generates more energy than it takes in and produces a heavier element. That is, until that heavier element is iron. Producing iron or anything heavier by fusion requires more energy than is released.
However, these heavier elements are still produced in star cores before nova because there's so much energy around for these reactions to happen. Not a lot of the heavy stuff in comparison to other elements, but still enough. And novas/supernovas distribute it in a continuous process that has been happening since the first giant star went supernova some time in the 1st 1/2 billion years of the universe. We are all nuclear waste, or as Carl Sagan said more poetically, "star stuff contemplating the stars."
Re:I thought there were a bunch
on
Warm-blooded Fish?
·
· Score: 2, Interesting
There was a quite interesting article in the Nov-Dec 2005 American Scientist:
It talks about how and why tuna and lamnid sharks have elevated muscle temperatures. Has to do with the way they swim. The neat thing is it explains why tuna and these sharks have that stiff-bodied way of swimming. The warm muscles are deep in the body along the spine, but pull tendons that move the airleron-like tail to propel the fish. They say that tuna have been clocked at nearly 70 mph for short distances.
Contrast this with regular fish, which swim by bending their entire bodies back and forth.
Another interesting thing is that the tuna and sharks have to swim constantly their entire lives or they will sink - no air bladder. The lack of a bladder meant they could descend much faster onto prey. As a result they literally must swim or sink.
Mod parent up! This is called Euler's identity, and it's the key to all trig.
On the other hand, I don't know what he's talking about with when he learned it. I got it in Calc 1, but the failed to show how it could be useful, preferring instead to show all the trig identities. Once I started on me electrical engineering classes, I used it daily in just about every homework problem beyond resistors.
It does take a bit of an understanding of complex numbers, and I think that's why they hold off. Lots of people get stuck on "imaginary" numbers. They are no less "real" than the reals, just a bad choice of name.
I've been an EE for 20 years, and I've only used trig identities a couple of times. On the other hand, I've manipulated complex powers of e so much I can do them in my sleep.
Knowing "trig" this well, with respect to the article, I have to say I can't imagine any way trig could be simplified.
Dude, get a life. Your problem is the games. You're lining the pockets of the video card makers and game software makers. "Out of the rat race" == stop spending so much time and money on playing games.
And yes, I practice what I preach. I recently was planning a major system upgrade to AMD64, perhaps dual core, something like 1.5 GB or more RAM, etc, etc. And then I decided that the four linux boxes I run at home are "just fine" for now (upgraded between 1 and 3 years ago). They'll have to do...
There was an article several years ago in American Scientist that talked about this. Domesticated animals all share a variety of interesting traits, one of which is variegated markings.
Another, from what I remember, had to do something with being a "permanent juvenile". Take a look at your basic dog's head. Cute, friendly shape. Then look at a wolf's head. More sinister shape. But the young wolves are "cute", like dogs. Somehow, domestication is responsible for the animal remaining a juvenile.
Anyway, I don't have the article any more, and AmSci wants money to search their index:-( It's all explained in the article...
If I would you I would give up the "scientific" test. Why? You need *immediate* MPG feedback. You need a car that displays instantaneous MPG. They exist; I have one.
The VW Passat trip computer shows instantaneous MPG, short trip MPG, and long trip MPG (manual reset). I believe the same computer is also in other VWs and in the Audi. This has been a boon for me because I've always watched my gas mileage by logging usage like you describe. I still do this just to verify the car computer (heck it's something to do).
My observations:
1) Don't jackrabbit start. I can watch the trip MPG just DROP when I drag race out of an intersection. It drops much much less with a gentle start.
2) "Coasting" really helps. Some would say this is unsafe, but I do it anyway (carefully).
3) Country roads at 35-45 MPH get me the best MPG; MPG is also worse at higher highway speeds (like 80 vs. 70; gets better as you go slower)
4) MPG drops in the winter. In fact, it's kind of sinusoidal over the year, with an overall average 27.5 MPG +/- 3 MPG.
I must say that my driving habits have changed significantly, now that I can watch the MPG on the display. I seriously think that this kind of computer should be in *all* cars, trucks, SUVs. Really lets you know where your money is going.
I would like to encrypt my credit card information for sending it over the Internet. Can someone *please* help me use this article to do that? I mean, where do I plug in the credit card number? Does it matter that mine doesn't end in "4" or "9"? Do I need the CCV?
I'm surprised we got as much detail! Should be something like "Some smart guy from a long time ago did some smart things, and now some other smart guy made them better..." Duuuuuh, that's what *I* got my degree for!
Randomness is too important to be left to chance!:-)
When all I had was a single disk CD player, "shuffle" was a useless activity. Turn the player on and hit shuffle, and the same disk would always play in the same "random" order.
Similar thing happened when I got a 5-disk CD player. "Shuffle" consistently produced inferior song orderings. For instance, shuffle might select most of the songs from the 3rd and 1st CDs and play mostly those before arriving at the least-played CDs and playing mostly those songs. When I put my 5 favorite CDs into the player and hit shuffle, I want a different sequence next time I turn the unit on, otherwise, what's the point?
Now with WinAmp/Xmms, I haven't confirmed this by extensive testing, but shuffle still seems to suck, and I'd rather hear a CD in the "intended" order rather than some software-selected random order.
I also listen to a streaming web radio station, and although the guy must have a 10,000 song archive, there are times when I hear the same song twice or even 3 times in a day. I have not asked, but my guess is again that it's a (pseudo) random shuffle.
At this point, I should probably define "sucks". Basically, I don't want to hear anything from the same CD successively, and I don't want shuffle to alternate between two CDs over several songs, and I'd like all CDs to be selected more or less uniformly... etc. There's a whole list of rules one could make to produce a "DJ-quality" playlist.
Anyway, I must admit that most of this is simply my own perception, since it hasn't really risen to a high enough priority to start chasing it down. What I'm wondering is whether other people have noticed this, and whether anyone has written any kind of shuffle software that does something "better" than "next_song_num = (int) (random_float()*number_of_songs)" for a shuffle algorithm. If not, then I think there's a great opportunity for someone to invent a shuffle heuristic, perhaps with some user-selectable tweaks, for incorporation into our favorite music players.
If you use PGP to protect your Internet mail, the Feds are going to know that you have _something_ going on and that they might want to keep extra tabs on you. If you also use steganographic techniques, you'll never show up on their radar in the first place.
This is true. The problem with steg is that generally, you must hide the message in something else that is not message. The higher the ratio of chaff to message, the harder to find the message, but also the larger the steg messages you must exchange. At some point *this* becomes suspect.
The advantage of steganography is that if done right, it can give you plausible deniability. For a really interesting read, check out the papers describing StegFS,a steganographic file system for Linux.
So I use this to call someone using Bellster, which forwards over VoIP to somwhere in Tanzania who has thier phone connected to Skype, which does a "skype out" to someone in Russia, who calls my friend with Vonage in Canada, reconnects with Bellster, which gets me back locally and calls my cell phone (2000+ free minutes!), which I answer. Did I leave anyone out? I wonder what the end-to-end delay would be?!?!
Well, it looks like it was a combination of doppler shift and actual displacement with time. See the pictures in the space.com article. These show the gas blobs over the course of eight months. We can't count on the blobs moving directly normal to us; there may be some component of motion toward or away from us.
Knowing how far away the blazar was would let one infer the speed of the blobs in the direction normal to us, while measuring the doppler shift would tell is the speed toward or away from us (compared to the blazar's doppler shift). Use some basic trig to get the speed relative to the blazar.
Interesting article as far as it goes, but they do not even mention how far away the blazar is from us. Is this thing next door or billions of light years away? Guess I'll have to wait for the real science report in Sky and Telescope.
Simple: measure the doppler shift. The blazar has a certain red shift, while the blobs have another, and the difference implies a certain speed. I *haven't* read the fine article yet, but that's how astronomers measure the speed of just about everything in the universe. Now to go read the article...
In fact, a better question to ask now is, do stars with spherical nebulae exhibit a strong magnetic field? The results reported were on the basis of asymmetrical nebulae, and in each case, evidence of a strong magnetic field was detected.
The article also states that the astronomers' next step is to try to detect magnetic fields around the stars that have spherical nebulae. If they find none, I would say this pretty much clinches the conclusion, at least until some other unexplained effect is discovered.
To directly address your question, if strong magnetic fields are the reason for asymmetric nebulae, then we should ask why do 20% of stars have a weak magnetic field? (Or, conversely, why do 80% of stars have a strong field)
Slashdot Mirror
The Adolescence of P-1
Not quite there yet and definitely a bit archaic in technology, but it's still amazing the book was written in 1977.
Great idea, this mechanical turk thing, but I think the example you gave shows its limitation if none of them objected even to the first item in your list:
1. Government should ban smoking by people under 18, because of the harmful health effects.
It's not because of the harmful effects, it's because people under 18 are not considered legally responsible for their actions. Yeah, there may be exceptions and inconsistencies to that (can't buy alcohol until you're 21, but you can die in a war at age 18, for instance), but that's the reason.
Anyway, you need at least one Turk that responds to each of your presumptions.
FYI, the Department of Redundancy Department (DRD Department) is conveniently located within the Department of of Superfluous Redundancies and Tautological Pleonasms Department (DSRTPD Department).
(Mod "redundant")
You're "in the field," eh? Are you an EE? You learn this stuff in a senior level comm class.
The "noise floor" (actually noise power spectral density) is determined by kT, Boltzmann constant times Kelvin temperature.
Looking into empty space, the noise temperature is the magical 3 K. As far as the receiver noise floor, astronomical receivers are typically cryogenically cooled just to reduce the noise floor. So, assuming receiver noise is lower than space noise, the noise PSD is -193.8 dBm/Hz.
And bandwidth? Depends on how fast/slow the message is. Add 10log(BW) to the noise PSD and THAT'S your noise floor.
Anyway, the link budget *is* difficult, but not impossible. It does require a certain amount of the other civilization actually *wanting* to be found, though.
I agree with it sounding redundant, so I did a Wikipedia search and found this link:
http://en.wikipedia.org/wiki/Laser_propulsion
Apparently, the laser can be used for a variety of things without actually being the prime mover. Still, since there's no description of "photonic laser" propulsion, I'm not clear on how the laser is doing anything.
It matters. Actually, what matters more is the actual exposure time vs. field of view. Just like in regular cameras, the higher the magnification (higher zoom), the narrower the field of view and the more sensitive the image will be to any motion during exposure.
For planetary images, you can do pretty well with short exposures and using align/stack software. By short, I mean 1/30 to 1/2 second. This will get you pictures of Mercury, Venus, Mars, Jupiter and Saturn.
For deep-sky stuff, you need to have much longer exposures, and you will often want a narrow field of view. For this, you will definitely need accurate RA tracking and a very accurate polar alignment. I have worked with up to 30 second exposures; this takes quite a bit of patience with a manual polar alignment.
Really wide field photos with a digital camera and no telescope is a lot easier to do, but most regular digital cameras aren't that sensitive (lots of noise in long exposures).
The equipment I have: 6" Matsukov-Cassegrain, Meade DSI color camera, plus an $800 mount (I forget the brand). This ran about $2.4K total.
I guess my main point would be that astophotography requires quite a bit of patience, and does not produce the kind of pictures you see in magazines without a lot of extra work and a lot of really expensive equipment. I didn't start out on this path right away and wouldn't recommend it unless you have a lot of money to spend.
Another way to look at it is everything I say here is wrong if you throw enough money at it!
Look for "tsunami"
Imagine a beowulf cluster of single photon servers!
Off topic, but heck, I get a lot of interesting info from off topic posts...
Hydrogen, helium and a tiny bit of lithium existed after the big bang. *Everything* heaver was created in the core of stars, or as a decay product of something produced in a star core. The reference to iron is a relevant, but not as the poster intended. Fusion of light elements generates more energy than it takes in and produces a heavier element. That is, until that heavier element is iron. Producing iron or anything heavier by fusion requires more energy than is released.
However, these heavier elements are still produced in star cores before nova because there's so much energy around for these reactions to happen. Not a lot of the heavy stuff in comparison to other elements, but still enough. And novas/supernovas distribute it in a continuous process that has been happening since the first giant star went supernova some time in the 1st 1/2 billion years of the universe. We are all nuclear waste, or as Carl Sagan said more poetically, "star stuff contemplating the stars."
There was a quite interesting article in the Nov-Dec 2005 American Scientist:
I ssue;jsessionid=baadyy7MHypG0u (subscription required)
http://www.americanscientist.org/template/Current
It talks about how and why tuna and lamnid sharks have elevated muscle temperatures. Has to do with the way they swim. The neat thing is it explains why tuna and these sharks have that stiff-bodied way of swimming. The warm muscles are deep in the body along the spine, but pull tendons that move the airleron-like tail to propel the fish. They say that tuna have been clocked at nearly 70 mph for short distances.
Contrast this with regular fish, which swim by bending their entire bodies back and forth.
Another interesting thing is that the tuna and sharks have to swim constantly their entire lives or they will sink - no air bladder. The lack of a bladder meant they could descend much faster onto prey. As a result they literally must swim or sink.
Mod parent up! This is called Euler's identity, and it's the key to all trig.
On the other hand, I don't know what he's talking about with when he learned it. I got it in Calc 1, but the failed to show how it could be useful, preferring instead to show all the trig identities. Once I started on me electrical engineering classes, I used it daily in just about every homework problem beyond resistors.
It does take a bit of an understanding of complex numbers, and I think that's why they hold off. Lots of people get stuck on "imaginary" numbers. They are no less "real" than the reals, just a bad choice of name.
I've been an EE for 20 years, and I've only used trig identities a couple of times. On the other hand, I've manipulated complex powers of e so much I can do them in my sleep.
Knowing "trig" this well, with respect to the article, I have to say I can't imagine any way trig could be simplified.
Dude, get a life. Your problem is the games. You're lining the pockets of the video card makers and game software makers. "Out of the rat race" == stop spending so much time and money on playing games.
And yes, I practice what I preach. I recently was planning a major system upgrade to AMD64, perhaps dual core, something like 1.5 GB or more RAM, etc, etc. And then I decided that the four linux boxes I run at home are "just fine" for now (upgraded between 1 and 3 years ago). They'll have to do...
In Soviet Russia, Microsoft loves YOU!
There was an article several years ago in American Scientist that talked about this. Domesticated animals all share a variety of interesting traits, one of which is variegated markings.
:-( It's all explained in the article...
Another, from what I remember, had to do something with being a "permanent juvenile". Take a look at your basic dog's head. Cute, friendly shape. Then look at a wolf's head. More sinister shape. But the young wolves are "cute", like dogs. Somehow, domestication is responsible for the animal remaining a juvenile.
Anyway, I don't have the article any more, and AmSci wants money to search their index
If I would you I would give up the "scientific" test. Why? You need *immediate* MPG feedback. You need a car that displays instantaneous MPG. They exist; I have one.
The VW Passat trip computer shows instantaneous MPG, short trip MPG, and long trip MPG (manual reset). I believe the same computer is also in other VWs and in the Audi. This has been a boon for me because I've always watched my gas mileage by logging usage like you describe. I still do this just to verify the car computer (heck it's something to do).
My observations:
1) Don't jackrabbit start. I can watch the trip MPG just DROP when I drag race out of an intersection. It drops much much less with a gentle start.
2) "Coasting" really helps. Some would say this is unsafe, but I do it anyway (carefully).
3) Country roads at 35-45 MPH get me the best MPG; MPG is also worse at higher highway speeds (like 80 vs. 70; gets better as you go slower)
4) MPG drops in the winter. In fact, it's kind of sinusoidal over the year, with an overall average 27.5 MPG +/- 3 MPG.
Test car: 2003 Passat sedan, manual trans, 1.8 liter turbo engine.
I must say that my driving habits have changed significantly, now that I can watch the MPG on the display. I seriously think that this kind of computer should be in *all* cars, trucks, SUVs. Really lets you know where your money is going.
I would like to encrypt my credit card information for sending it over the Internet. Can someone *please* help me use this article to do that? I mean, where do I plug in the credit card number? Does it matter that mine doesn't end in "4" or "9"? Do I need the CCV?
I'm surprised we got as much detail! Should be something like "Some smart guy from a long time ago did some smart things, and now some other smart guy made them better..." Duuuuuh, that's what *I* got my degree for!
Randomness is too important to be left to chance! :-)
When all I had was a single disk CD player, "shuffle" was a useless activity. Turn the player on and hit shuffle, and the same disk would always play in the same "random" order.
Similar thing happened when I got a 5-disk CD player. "Shuffle" consistently produced inferior song orderings. For instance, shuffle might select most of the songs from the 3rd and 1st CDs and play mostly those before arriving at the least-played CDs and playing mostly those songs. When I put my 5 favorite CDs into the player and hit shuffle, I want a different sequence next time I turn the unit on, otherwise, what's the point?
Now with WinAmp/Xmms, I haven't confirmed this by extensive testing, but shuffle still seems to suck, and I'd rather hear a CD in the "intended" order rather than some software-selected random order.
I also listen to a streaming web radio station, and although the guy must have a 10,000 song archive, there are times when I hear the same song twice or even 3 times in a day. I have not asked, but my guess is again that it's a (pseudo) random shuffle.
At this point, I should probably define "sucks". Basically, I don't want to hear anything from the same CD successively, and I don't want shuffle to alternate between two CDs over several songs, and I'd like all CDs to be selected more or less uniformly... etc. There's a whole list of rules one could make to produce a "DJ-quality" playlist.
Anyway, I must admit that most of this is simply my own perception, since it hasn't really risen to a high enough priority to start chasing it down. What I'm wondering is whether other people have noticed this, and whether anyone has written any kind of shuffle software that does something "better" than "next_song_num = (int) (random_float()*number_of_songs)" for a shuffle algorithm. If not, then I think there's a great opportunity for someone to invent a shuffle heuristic, perhaps with some user-selectable tweaks, for incorporation into our favorite music players.
This is true. The problem with steg is that generally, you must hide the message in something else that is not message. The higher the ratio of chaff to message, the harder to find the message, but also the larger the steg messages you must exchange. At some point *this* becomes suspect.
The advantage of steganography is that if done right, it can give you plausible deniability. For a really interesting read, check out the papers describing StegFS ,a steganographic file system for Linux.
So I use this to call someone using Bellster, which forwards over VoIP to somwhere in Tanzania who has thier phone connected to Skype, which does a "skype out" to someone in Russia, who calls my friend with Vonage in Canada, reconnects with Bellster, which gets me back locally and calls my cell phone (2000+ free minutes!), which I answer. Did I leave anyone out? I wonder what the end-to-end delay would be?!?!
Knowing how far away the blazar was would let one infer the speed of the blobs in the direction normal to us, while measuring the doppler shift would tell is the speed toward or away from us (compared to the blazar's doppler shift). Use some basic trig to get the speed relative to the blazar.
Interesting article as far as it goes, but they do not even mention how far away the blazar is from us. Is this thing next door or billions of light years away? Guess I'll have to wait for the real science report in Sky and Telescope.
Simple: measure the doppler shift. The blazar has a certain red shift, while the blobs have another, and the difference implies a certain speed. I *haven't* read the fine article yet, but that's how astronomers measure the speed of just about everything in the universe. Now to go read the article...
1) Make impact by thinking out of the box
2) Leverage paradigm shift
3) ????
4) Profit!!!
In fact, a better question to ask now is, do stars with spherical nebulae exhibit a strong magnetic field? The results reported were on the basis of asymmetrical nebulae, and in each case, evidence of a strong magnetic field was detected.
The article also states that the astronomers' next step is to try to detect magnetic fields around the stars that have spherical nebulae. If they find none, I would say this pretty much clinches the conclusion, at least until some other unexplained effect is discovered.
To directly address your question, if strong magnetic fields are the reason for asymmetric nebulae, then we should ask why do 20% of stars have a weak magnetic field? (Or, conversely, why do 80% of stars have a strong field)