They aren't necessarily teleological. A system with only positive feedback mechanisms will quickly end in one extreme. The climate of Earth is neither comparable to that of Mars nor to that of Venus, so there must be some negative feedback mechanisms. They might take a few million years to work, though (see my previous comment for one example: http://science.slashdot.org/comments.pl?sid=3100167&cid=41257817).
IIRC, global warming leads to more rain, which lead to more erosion. Some newly eroded rocks can take up CO2. This is believed to be the reason for repeated snowballing of the earth: Erosion removes CO2, the climate gets cooler, glaciers mean no erosion, CO2 and SO2 from volcanoes slowly build up until they warm the earth enough for the glaciers to melt and get erosion starting.
Of course, this works on far to slow a time scale for it to matter for humans.
If the underwear bomber did use liquid explosives, that is an example of someone trying. He also failed, illustrating that it is hard, probably to the point where it makes no sense to screen for it.
How big a part if the ISS's power budget is life support? How much lighter and smaller could it be if it did not have to accommodate humans? If there were no humans aboard, it would be much easier to shut of some systems temporarily or permanently in case of power problems.
In short, humans make space travel large, energy-intensive and expensive. Sure, they also make it more flexible, but it is not a given that that outweighs the massively more complex operations they require.
Teachers shouldn't care how their students perform on standardized tests, nor should students. It's bad science to care how your results turn out.
Teaching aren't doing science. They are not trying to find the best way to teach, they are trying to educate the children*. They should care about the result, about how well educated the children become. If we had some way to perfectly asses how well the children were educated, it would be fine for the teachers to care about that. The problem is that the tests we have don't do that.
*Part of any job is to figure out how best to do it, but it is not the job itself. If I am paid to build houses, it is smart of me to figure out how to do that faster, cheaper, and with higher quality, but the end result is the house, not the method.
He made the point that every teacher knows that beginning teachers improve a lot from their first to second year (conversely, most teachers agree that they had a lot of trouble in their first year).
How do we know that teachers become better teachers? We know that they feel that, but do we know that the children learn more? One of Mazurs points about peer instruction* is that most of what we think matters in learning simply doesn't. If you design a test of understanding**, it turns out the the gain is remarkably constant over a wide range of teachers and schools, regardless of teacher experience and teacher evaluation by the students, even if the teachers think differently.
Not that I necessarily disagree with you main points, it is very hard to make good tests, and it seems easy, so most tests will probably be really bad. The video also strengthens your point about poverty, the understanding after teaching is partly determined by the understanding before teaching, so simply testing after teaching is not a good way to asses the Teachers ability.
*I hope that is the correct video, this computer can't play them.
** Assuming that this example is well designed, which is, of course, hard to verify. It does, at least, try to test understanding, and not just knowledge.
Why not? Do you have some special insights? [...]WD-40 is primarily composed of various hydrocarbons
Hydrocarbons have a vapor pressure, which means they will evaporate in space. You have to use something like molybdenum sulfide. About a decade ago, I saw a proposal to us metal-sulfide fullerenes to make the worlds smallest ball bearing, but I haven't heard about it since, so it probalby didn't work out.
In winter, there are just about no insects to be found (at least, not outside). However, when it's around -40C, the transparent clothing would need a good insulation value, and would likely be layered and thick so its transparency would be somewhat debatable.
Aerogel is a good thermal insulator, and can be transparent. Now we just need to make the flexible types transparent, or make the transparant types flexible.
This not only can weigh a single molecule, it also can dramatically outperform existing sensors when measuring the mass of very large molecules (think protein complexes, viruses, and so on).
In what ways does it outperform existing detectors? I have seen a MALDI-TOF mass spectrum of a E. Coli cell, so it can't be m/z range.
The ability to further reduce the physical size (and power consumption) of a mass spec will also pay dividends for using mass spec for diagnostic applications.
doesn't this require a vacuum? A quadropole MS can be quite small, but the vacuum pumps are large.
It should never fail, but NASA also said the shuttle would never fail and would have a turn around time measured in weeks.
IIRC, the original estimate for the shuttle was 1% risk of failure at each launch. With 2 failures in 135 shuttle missions, it seems that they nailed it. We should be able to achieve them same rate with plutonium-carrying rockets if we are willing to pay the price, but in most cases, the plutonium containment will not fail, so we are probably looking at one plutonium dispersion event every 1000-10.000 launches.
Furthermore, plutonium and plutonium oxides are heavy. You can breath them for a short time, but they will quickly settle as dust, after which breathing is not possible. Plutonium oxides mostly passes unaffected through the human digestive tract (IIRC, about 1% is taken up), so there is no reason to suspect that the land will be unihabitable. If people were rational, they would just have to move people out for a week or two, and then they could move back. Of course, moving back to land that is contaminated with plutonium, even if everybody says it is OK, is not something most people will enjoy.
Rape fantasy and its elder brother the S&M subculture both need to be, if not actively stamped out, at least actively despised by as many people as possible, on a permanent basis.
Yes, oppressing sexual minorities is always a winning strategy. Just like we all know that homosexual men cannot help but to seduce adolescent boys, we know that the mere existance of S&M is what leads to rape. Neither should be tolerated.
I'm fairly tolerant [...]
No, you're not. Of course, there's a fine analogy to people who say "I'm not racist, but..."
Not necessarily. It seems that the wavelengths where n is close 1 (refractive index close to the one of air), k (the absorption) is large, so the light will not get far. This might be fine for a few inches of snow, but not for seeing through meters of snow. It also helps that the lines on the side of the rode is covered with retroreflectors. Unless you can convince skiers to where reflective clothing, this won't be the case in avalanche victims. Or Frosty's underwear (I hope, but please don't tell me if it is).
I have a much harder one for you, that I've dealt with myself once (and admittedly not with 100% success): a road covered in fresh snow. No lines visible, everything white. In the dark, with the edge of the road only detectable by a small drop in the snow level and the occasional pole sticking out, snowed-over reflector optional.
Have one of the systems see in a wavelength where the refractive index of water ice is close to the refractive index of air. Snow will be transparent.
In the UK, a merger that will result in a company having more than 25% market share can be prohibited under the monopoly laws, so 50% might not be the correct percentage to cehck for. However, I don't think any countries prohibit monopolies, just using those monopolies to distort the market in certain ways.
Not for Danish cards. Here, the first 4 are country and card type, the next 4 are the bank registration number. I would think this was the case for all non-American cards, but I could very well be wrong.
It really is a balance: Give it too few possibilties, and it becomes boring. Give it too many possibilities, and it becomes random. Entertaining is somewhere in between. I would put gliders, as defined in CA, at the lower end of interesting, so making it more complex could remove gliders. Gliders isn't just movement, roughly speaking it is movement without change. A rock flying through the ground is a glider, a horse isn't, as it uses energy, so it doesn't return to the same state.
They used solid phase extraction, a common technique in analytical chemistry: The water was passed through an adsorbent which trapped caffeine and not water or salt. The sorbent was then washed with dichloromethane to release the caffeine in a much smaller volume, and thus higher concentration. The adsorbent has a limited capacity, so other stuff in sea water could wash out the caffeine. By evaporating, you also concentrate these, so you cannot trap any more caffeine. Besides, the boiling point of caffeine is not that high, so due to the low molecular mass of water, you will lose quite a lot of caffeine by evaporation.
Gliders are commonplace on repeating grids. According to TFA (and this makes sense), it was thought that they could not be made on non-repeating grids. After all, which direction should it follow? How to make sure it can even exist in the place it will move to?
However, I feel that by allowing more types of tiles, it should be clear that it was possible. For example, with four types of cells, you could have "front of glider" (becomes "back of glider") "back of glider" (becomes "not glider") "side of glider" to keep the rest in check (keeps status unless in contact with "back of glider", when it becomes "not glider") "not glider" (becomes "side of glider" if in contact with one "side of glider" and one "front of glider", becomes "front of glider" if in contact with two "side of glider" and no "back of glider")
Slashdot Mirror
They aren't necessarily teleological. A system with only positive feedback mechanisms will quickly end in one extreme. The climate of Earth is neither comparable to that of Mars nor to that of Venus, so there must be some negative feedback mechanisms. They might take a few million years to work, though (see my previous comment for one example: http://science.slashdot.org/comments.pl?sid=3100167&cid=41257817).
IIRC, global warming leads to more rain, which lead to more erosion. Some newly eroded rocks can take up CO2. This is believed to be the reason for repeated snowballing of the earth: Erosion removes CO2, the climate gets cooler, glaciers mean no erosion, CO2 and SO2 from volcanoes slowly build up until they warm the earth enough for the glaciers to melt and get erosion starting.
Of course, this works on far to slow a time scale for it to matter for humans.
If the underwear bomber did use liquid explosives, that is an example of someone trying. He also failed, illustrating that it is hard, probably to the point where it makes no sense to screen for it.
The ban on liquids was instated after the first instance I linked to, IIRC.
Sorry for the double answer.
http://en.wikipedia.org/wiki/2006_transatlantic_aircraft_plot#Liquid_explosives
It seems the underwear bomber also had some part of his bomb as liquid, but the details elude me.
How big a part if the ISS's power budget is life support? How much lighter and smaller could it be if it did not have to accommodate humans? If there were no humans aboard, it would be much easier to shut of some systems temporarily or permanently in case of power problems.
In short, humans make space travel large, energy-intensive and expensive. Sure, they also make it more flexible, but it is not a given that that outweighs the massively more complex operations they require.
Silicones are manufactured.
Teachers shouldn't care how their students perform on standardized tests, nor should students. It's bad science to care how your results turn out.
Teaching aren't doing science. They are not trying to find the best way to teach, they are trying to educate the children*. They should care about the result, about how well educated the children become. If we had some way to perfectly asses how well the children were educated, it would be fine for the teachers to care about that. The problem is that the tests we have don't do that.
*Part of any job is to figure out how best to do it, but it is not the job itself. If I am paid to build houses, it is smart of me to figure out how to do that faster, cheaper, and with higher quality, but the end result is the house, not the method.
He made the point that every teacher knows that beginning teachers improve a lot from their first to second year (conversely, most teachers agree that they had a lot of trouble in their first year).
How do we know that teachers become better teachers? We know that they feel that, but do we know that the children learn more? One of Mazurs points about peer instruction* is that most of what we think matters in learning simply doesn't. If you design a test of understanding**, it turns out the the gain is remarkably constant over a wide range of teachers and schools, regardless of teacher experience and teacher evaluation by the students, even if the teachers think differently.
Not that I necessarily disagree with you main points, it is very hard to make good tests, and it seems easy, so most tests will probably be really bad. The video also strengthens your point about poverty, the understanding after teaching is partly determined by the understanding before teaching, so simply testing after teaching is not a good way to asses the Teachers ability.
*I hope that is the correct video, this computer can't play them.
** Assuming that this example is well designed, which is, of course, hard to verify. It does, at least, try to test understanding, and not just knowledge.
"In space WD-40 is not really an option."
Why not? Do you have some special insights? [...]WD-40 is primarily composed of various hydrocarbons
Hydrocarbons have a vapor pressure, which means they will evaporate in space. You have to use something like molybdenum sulfide. About a decade ago, I saw a proposal to us metal-sulfide fullerenes to make the worlds smallest ball bearing, but I haven't heard about it since, so it probalby didn't work out.
Because there is no difference between patents and trademarks, right?
In winter, there are just about no insects to be found (at least, not outside). However, when it's around -40C, the transparent clothing would need a good insulation value, and would likely be layered and thick so its transparency would be somewhat debatable.
Aerogel is a good thermal insulator, and can be transparent. Now we just need to make the flexible types transparent, or make the transparant types flexible.
I read the blurb to mean measuring the gravitational force on a molecule.
This technique measures the effect on the vibrational frequency of the bridge, so it measures the inertial mass.
This not only can weigh a single molecule, it also can dramatically outperform existing sensors when measuring the mass of very large molecules (think protein complexes, viruses, and so on).
In what ways does it outperform existing detectors? I have seen a MALDI-TOF mass spectrum of a E. Coli cell, so it can't be m/z range.
The ability to further reduce the physical size (and power consumption) of a mass spec will also pay dividends for using mass spec for diagnostic applications.
doesn't this require a vacuum? A quadropole MS can be quite small, but the vacuum pumps are large.
It should never fail, but NASA also said the shuttle would never fail and would have a turn around time measured in weeks.
IIRC, the original estimate for the shuttle was 1% risk of failure at each launch. With 2 failures in 135 shuttle missions, it seems that they nailed it. We should be able to achieve them same rate with plutonium-carrying rockets if we are willing to pay the price, but in most cases, the plutonium containment will not fail, so we are probably looking at one plutonium dispersion event every 1000-10.000 launches.
Furthermore, plutonium and plutonium oxides are heavy. You can breath them for a short time, but they will quickly settle as dust, after which breathing is not possible. Plutonium oxides mostly passes unaffected through the human digestive tract (IIRC, about 1% is taken up), so there is no reason to suspect that the land will be unihabitable. If people were rational, they would just have to move people out for a week or two, and then they could move back. Of course, moving back to land that is contaminated with plutonium, even if everybody says it is OK, is not something most people will enjoy.
It's in a pretty good vacuum, and the volume is quite small (it starts out the size of two lead nuclei, after all), so probably not.
Rape fantasy and its elder brother the S&M subculture both need to be, if not actively stamped out, at least actively despised by as many people as possible, on a permanent basis.
Yes, oppressing sexual minorities is always a winning strategy. Just like we all know that homosexual men cannot help but to seduce adolescent boys, we know that the mere existance of S&M is what leads to rape. Neither should be tolerated.
I'm fairly tolerant [...]
No, you're not. Of course, there's a fine analogy to people who say "I'm not racist, but..."
Not necessarily. It seems that the wavelengths where n is close 1 (refractive index close to the one of air), k (the absorption) is large, so the light will not get far. This might be fine for a few inches of snow, but not for seeing through meters of snow. It also helps that the lines on the side of the rode is covered with retroreflectors. Unless you can convince skiers to where reflective clothing, this won't be the case in avalanche victims. Or Frosty's underwear (I hope, but please don't tell me if it is).
I have a much harder one for you, that I've dealt with myself once (and admittedly not with 100% success): a road covered in fresh snow. No lines visible, everything white. In the dark, with the edge of the road only detectable by a small drop in the snow level and the occasional pole sticking out, snowed-over reflector optional.
Have one of the systems see in a wavelength where the refractive index of water ice is close to the refractive index of air. Snow will be transparent.
In the UK, a merger that will result in a company having more than 25% market share can be prohibited under the monopoly laws, so 50% might not be the correct percentage to cehck for. However, I don't think any countries prohibit monopolies, just using those monopolies to distort the market in certain ways.
Not for Danish cards. Here, the first 4 are country and card type, the next 4 are the bank registration number. I would think this was the case for all non-American cards, but I could very well be wrong.
It really is a balance: Give it too few possibilties, and it becomes boring. Give it too many possibilities, and it becomes random. Entertaining is somewhere in between. I would put gliders, as defined in CA, at the lower end of interesting, so making it more complex could remove gliders. Gliders isn't just movement, roughly speaking it is movement without change. A rock flying through the ground is a glider, a horse isn't, as it uses energy, so it doesn't return to the same state.
The first eight are not random*, so if the last four is out, only number 9-12 are left.
*In fact, for any one type of card from any one Danish bank, the first 8 are identical.
They used solid phase extraction, a common technique in analytical chemistry: The water was passed through an adsorbent which trapped caffeine and not water or salt. The sorbent was then washed with dichloromethane to release the caffeine in a much smaller volume, and thus higher concentration. The adsorbent has a limited capacity, so other stuff in sea water could wash out the caffeine. By evaporating, you also concentrate these, so you cannot trap any more caffeine. Besides, the boiling point of caffeine is not that high, so due to the low molecular mass of water, you will lose quite a lot of caffeine by evaporation.
Gliders are commonplace on repeating grids. According to TFA (and this makes sense), it was thought that they could not be made on non-repeating grids. After all, which direction should it follow? How to make sure it can even exist in the place it will move to?
However, I feel that by allowing more types of tiles, it should be clear that it was possible. For example, with four types of cells, you could have
"front of glider" (becomes "back of glider")
"back of glider" (becomes "not glider")
"side of glider" to keep the rest in check (keeps status unless in contact with "back of glider", when it becomes "not glider")
"not glider" (becomes "side of glider" if in contact with one "side of glider" and one "front of glider", becomes "front of glider" if in contact with two "side of glider" and no "back of glider")
This seems to be what they have done.