In a previous thread I wrote a response to a similar question which I'll paste here. The question was a bit different (concerning how fast drug resistance would be lost over time), and related to organisms other than TB (for instance, TB drug resistance isn't plasmid-mediated, as far as I know) -- so my reply doesn't directly respond to your question. However, the gist is the same -- with prolonged evolutionary selection, drug resistance mechanisms with high costs will be gradually replaced by more efficient solutions.
Loss-of-function or alterations of form are indeed one of of the possible mechanisms, and tends to be the more easily-evolved type, so you will often see those appear (and disappear) the fastest. However, occasionally you see mutations that are "free" to the bug, and represent a genuine evolutionary advance that will stick around, possibly forever.
Outside of this, resistance mechanisms are mostly plasmid-encoded factors for things such as antibiotic-degrading enzymes, efflux pumps, and other such defenses. The evolutionary cost for these can range from very high to trivially low, depending (does your enzyme soak up lots of resources to make, or is it highly efficient? Is it permanently switched on, or does it come with an induction mechanism that only triggers when appropriate?). In addition, many bacteria can swap plasmids around, allowing for more genetic versatility.
So the short answer is, that there is no short answer. How fast resistance disappears when antibiotics are no longer used, will depend on each particular situation. However, over time quick-and-dirty solutions will tend to be replaced by more evolutionarily elegant adaptations.
You're trying to be funny here, but as the linked nature article says, "Tuberculosis trails behind only HIV as the world’s leading cause of death from infectious disease."-- and unlike HIV, it has been circulating since antiquity. There's a fair bit of speculation (though difficult to prove) that evolutionary pressure from TB has contributed to some types of autoimmune disease susceptibility.
There are many more liquids in the world than water. How does this coating stand up to something as corrosive as salt water or Coke?
Presumably well, hydrophobic coatings are apparently quite good at reducing corrosion. I'd be more interested to know how it stands up to something capable of wetting hydrophobic surfaces, like alcohol. Or with some fat content, like whole milk or soup.
I've been racking my brains to try to remember the name -- there's a "Law" used in the chemical industry which estimates the price required to concentrate a substance. It's not so much a physical law as an observation (much like Moore's Law). But like Moore's law, it gives some pretty good ballpark estimates.
If anyone here remembers the name let me know -- it's driving me nuts. I remember an article in either Science or Nature recently mentioned it.
... Dress sharply at all times, and keep a business-like posture and demeanour. Playing bully with a peon is safe enough, but harassing an (apparently) wealthy and influent person is a career-destroying move. You don't mess with the Ruling Elite, so might as well camouflage as one.
I didn't realize that it is actually possible for a government to decide their people are having too much fun.
What us westerners don't realize, is that the Chinese programs have become so excessively entertaining, they are in danger of creating "The Entertainment", and are banning such programs to ensure their own survival!
The Washington Post (reg required) just had a good report on how Russia's scientific base has changed for the worse. Apparently, the labs are populated with a bimodal mix of young and elderly scientists -- the middle has been hollowed out over the last two decades. And while a new funding push has sent money towards science, much of it is wasted through corruption:
And then the Chinese send it right back by buying U.S. Treasuries and other dollar-denominated investments. The U.S. ends up with cash and the stuff the cash paid for; the Chinese end up with a bunch of IOUs.
The real value of the American IOUs is to give them the financial hook needed to introduce the Yuan as a major world reserve currency, the way the Dollar, Euro, and Yen are used. They could do it now, if they were willing to remove the various legal restrictions they have on currency movement (but are probably enjoying the currency manipulation benefits too much to do it, yet).
So what? It's not like iPads and iPhones are the only devices they're making. In fact, China, Taiwan, Japan, Thailand and other Asian countries are making almost all of electronics in the whole world. They might only profit 2% of every device, but the sheer scale of the whole manufacturing industry more than makes up for that.
There's an appropriate quote by TSMC Chairman Morris Chang: "You Americans measure profitability by a ratio. There’s a problem with that. No banks accept deposits denominated in ratios. The way we measure profitability is in 'tons of money'. You use the return on assets ratio if cash is scarce. But if there is actually a lot of cash, then that is causing you to economize on something that is abundant."
I've never been interested in Bitcoin mining, but as it becomes less worthwhile, I'm hoping it will depress prices on the used graphics card market, as former miners liquidate their rigs.
Coupled with their ARM CPU developments, I think Apple is attempting to remove their dependency on component makers such as Samsung (or at least gain some IP to use as leverage). I wouldn't be surprised if Apple starts some Flash-related patent wars in a few more years.
Data from DRAMeXchange also showed that rush orders for SSDs increased after the Thailand flooding disrupted hard disk drive supplies.
According to DRAMeXchange, a research division of TrendForce, rush orders for SSDs rose even as shipments of end-market products, including PCs, smartphones and tablet PCs, remained slugish because of slow economic conditions.
Despite SSDs not being an exact replacement for spinning rust, it looks like the HD shortage is indeed having the predicted effects on the SSD market.
I hope this vaccine is as effective as the smallpox and polio vaccines have been.
It's a technically sophisticated piece of work. But as someone who has previously worked on an HIV vaccine, I don't see any indications they've solved the fundamental problems that have dogged all previous attempts. With the exception of a very small number of "elite controller" individuals, the adaptive immune system just simply does not seem to be capable of handling this particular virus.
Please, before responding with an idiotic "But how will my doctor know what they are doing?!?!", think about this for more than 2 seconds
Let me use an analogy suitable for Slashdot.
You can learn a lot of about female anatomy from pictures, descriptions, and virtual models. And I'm sure many on this site have studied just materials at great length.
However, such materials are likely to leave you with misconceptions and an incomplete set of knowledge. A real specimen provides features such as 3D viewing and tactile feedback -- all these things will teach you things you would otherwise might not understand (Protip: They do not feel like bags of sand).
The vast majority of students in undergraduate biology classes will never in their lives have to cut open and dissect another animal of any kind, and the knowledge they gain from it could easily be gained by simulation.
Speaking as a medical school student, I'd say it depends on what you want to study and train the student to do afterwards.
If you are teaching the student using virtual methods, and then measure the student's performance using models and drawings afterwards -- you will probably find that the student's performance is actually higher than that of using real-life cadavers (not surprisingly, because you are training in the same manner as you are testing).
Their ability to regurgitate names for everything everything will probably be better, too. Because all the pieces are nice and discrete. Easy to memorize.
Now, real world bodies are different. In a preserved cadaver, everything is rendered in a few shades of brown/yellow/gray that blur together, (one exception: the gallbladder is a beautiful shade of green). If dissecting something not preserved and alive (or recently alive), smear red over everything (That's how you get stories about surgeons leaving sponges and stuff in bodies. Stuff ends up looking like red blobs sitting among a collection of red blobs).
It's very difficult to learn from a cadaver; A bunch of different structures in the book might just look like one big chunk in the body (cause maybe they're all enveloped and held together by connective tissue). Unlike a piece of designed equipment that needed to be assembled, everything space is stuffed and crammed with something or another, because it probably grew there. Except when it didn't grow there, it grew somewhere else and migrated. And because it was grown and not made, often it's not quite the shape or location that the book says.
As a result, learning to navigate around a body and recognize it's components is a special skill that goes far beyond memorizing those components themselves. There's a lot of reasoning and tracing connections and relationships. You don't just learn things from a cadaver, you learn skills.
I was thinking the same thing, organic substrates are so fragile. The lifespan problems involved are very much like those encountered in OLED material development, except even worse (due to the harsher usage conditions).
Hopefully, this will also push for substitutions using less-toxic fracking fluid components, even if some of these components may be higher cost.
For instance (pulling hypothetical example out of my butt, no personal expertise in fracking fluid chemistry) a mineral-oil based carrier vs. a diesel-fuel carrier. I mean, the mechanical properties of the fracking fluid seem like the most important, right? So there should be some fungibility regarding exact chemistry used.
"As the Americans learned so painfully in Earth's final century, free flow of information is the only safeguard against tyranny. The once-chained people whose leaders at last lose their grip on information flow will soon burst with freedom and vitality, but the free nation gradually constricting its grip on public discourse has begun its rapid slide into despotism. Beware of he who would deny you access to information, for in his heart he dreams himself your master."
Slashdot Mirror
In a previous thread I wrote a response to a similar question which I'll paste here. The question was a bit different (concerning how fast drug resistance would be lost over time), and related to organisms other than TB (for instance, TB drug resistance isn't plasmid-mediated, as far as I know) -- so my reply doesn't directly respond to your question. However, the gist is the same -- with prolonged evolutionary selection, drug resistance mechanisms with high costs will be gradually replaced by more efficient solutions.
Loss-of-function or alterations of form are indeed one of of the possible mechanisms, and tends to be the more easily-evolved type, so you will often see those appear (and disappear) the fastest. However, occasionally you see mutations that are "free" to the bug, and represent a genuine evolutionary advance that will stick around, possibly forever.
Outside of this, resistance mechanisms are mostly plasmid-encoded factors for things such as antibiotic-degrading enzymes, efflux pumps, and other such defenses. The evolutionary cost for these can range from very high to trivially low, depending (does your enzyme soak up lots of resources to make, or is it highly efficient? Is it permanently switched on, or does it come with an induction mechanism that only triggers when appropriate?). In addition, many bacteria can swap plasmids around, allowing for more genetic versatility.
So the short answer is, that there is no short answer. How fast resistance disappears when antibiotics are no longer used, will depend on each particular situation. However, over time quick-and-dirty solutions will tend to be replaced by more evolutionarily elegant adaptations.
You're trying to be funny here, but as the linked nature article says, "Tuberculosis trails behind only HIV as the world’s leading cause of death from infectious disease."-- and unlike HIV, it has been circulating since antiquity. There's a fair bit of speculation (though difficult to prove) that evolutionary pressure from TB has contributed to some types of autoimmune disease susceptibility.
There are many more liquids in the world than water. How does this coating stand up to something as corrosive as salt water or Coke?
Presumably well, hydrophobic coatings are apparently quite good at reducing corrosion. I'd be more interested to know how it stands up to something capable of wetting hydrophobic surfaces, like alcohol. Or with some fat content, like whole milk or soup.
What I've read in the media of this process suggests that it's parylene. http://en.wikipedia.org/wiki/Parylene [wikipedia.org]
Doesn't parylene turn yellowish under UV exposure though? Except for the fluropolymer version (which I suppose it could be).
I've been racking my brains to try to remember the name -- there's a "Law" used in the chemical industry which estimates the price required to concentrate a substance. It's not so much a physical law as an observation (much like Moore's Law). But like Moore's law, it gives some pretty good ballpark estimates.
If anyone here remembers the name let me know -- it's driving me nuts. I remember an article in either Science or Nature recently mentioned it.
... Dress sharply at all times, and keep a business-like posture and demeanour. Playing bully with a peon is safe enough, but harassing an (apparently) wealthy and influent person is a career-destroying move. You don't mess with the Ruling Elite, so might as well camouflage as one.
In other words, not so much camoflauge as Batesian Mimicry .
I didn't realize that it is actually possible for a government to decide their people are having too much fun.
What us westerners don't realize, is that the Chinese programs have become so excessively entertaining, they are in danger of creating "The Entertainment", and are banning such programs to ensure their own survival!
The Washington Post (reg required) just had a good report on how Russia's scientific base has changed for the worse. Apparently, the labs are populated with a bimodal mix of young and elderly scientists -- the middle has been hollowed out over the last two decades. And while a new funding push has sent money towards science, much of it is wasted through corruption:
In Russia, the lost generation of science
And then the Chinese send it right back by buying U.S. Treasuries and other dollar-denominated investments. The U.S. ends up with cash and the stuff the cash paid for; the Chinese end up with a bunch of IOUs.
The real value of the American IOUs is to give them the financial hook needed to introduce the Yuan as a major world reserve currency, the way the Dollar, Euro, and Yen are used. They could do it now, if they were willing to remove the various legal restrictions they have on currency movement (but are probably enjoying the currency manipulation benefits too much to do it, yet).
So what? It's not like iPads and iPhones are the only devices they're making. In fact, China, Taiwan, Japan, Thailand and other Asian countries are making almost all of electronics in the whole world. They might only profit 2% of every device, but the sheer scale of the whole manufacturing industry more than makes up for that.
There's an appropriate quote by TSMC Chairman Morris Chang: "You Americans measure profitability by a ratio. There’s a problem with that. No banks accept deposits denominated in ratios. The way we measure profitability is in 'tons of money'. You use the return on assets ratio if cash is scarce. But if there is actually a lot of cash, then that is causing you to economize on something that is abundant."
This extends to the general lighting market too, as PHOLED will be required because of efficiency.
I wonder if PHOLED efficiency will result in a longevity advantage too, if the wasted energy in OLEDs contributes to its degradation?
ED-209: "Citizen! Please step away from the pudding!"
*BRRRRRT-SplatterGibSploosh*"
ED-209: "Thank you for your cooperation."
I've never been interested in Bitcoin mining, but as it becomes less worthwhile, I'm hoping it will depress prices on the used graphics card market, as former miners liquidate their rigs.
Is it a dot or is it a speck?
When it's underwater does it get wet?
Nobody knows; Particle man...
Coupled with their ARM CPU developments, I think Apple is attempting to remove their dependency on component makers such as Samsung (or at least gain some IP to use as leverage). I wouldn't be surprised if Apple starts some Flash-related patent wars in a few more years.
From the article:
Data from DRAMeXchange also showed that rush orders for SSDs increased after the Thailand flooding disrupted hard disk drive supplies.
According to DRAMeXchange, a research division of TrendForce, rush orders for SSDs rose even as shipments of end-market products, including PCs, smartphones and tablet PCs, remained slugish because of slow economic conditions.
Despite SSDs not being an exact replacement for spinning rust, it looks like the HD shortage is indeed having the predicted effects on the SSD market.
I hope this vaccine is as effective as the smallpox and polio vaccines have been.
It's a technically sophisticated piece of work. But as someone who has previously worked on an HIV vaccine, I don't see any indications they've solved the fundamental problems that have dogged all previous attempts. With the exception of a very small number of "elite controller" individuals, the adaptive immune system just simply does not seem to be capable of handling this particular virus.
Please, before responding with an idiotic "But how will my doctor know what they are doing?!?!", think about this for more than 2 seconds
Let me use an analogy suitable for Slashdot.
You can learn a lot of about female anatomy from pictures, descriptions, and virtual models. And I'm sure many on this site have studied just materials at great length.
However, such materials are likely to leave you with misconceptions and an incomplete set of knowledge. A real specimen provides features such as 3D viewing and tactile feedback -- all these things will teach you things you would otherwise might not understand (Protip: They do not feel like bags of sand).
The vast majority of students in undergraduate biology classes will never in their lives have to cut open and dissect another animal of any kind, and the knowledge they gain from it could easily be gained by simulation.
So, to continue my Slashdot analogy. Um, Yeah...
Speaking as a medical school student, I'd say it depends on what you want to study and train the student to do afterwards.
If you are teaching the student using virtual methods, and then measure the student's performance using models and drawings afterwards -- you will probably find that the student's performance is actually higher than that of using real-life cadavers (not surprisingly, because you are training in the same manner as you are testing).
Their ability to regurgitate names for everything everything will probably be better, too. Because all the pieces are nice and discrete. Easy to memorize.
Now, real world bodies are different. In a preserved cadaver, everything is rendered in a few shades of brown/yellow/gray that blur together, (one exception: the gallbladder is a beautiful shade of green). If dissecting something not preserved and alive (or recently alive), smear red over everything (That's how you get stories about surgeons leaving sponges and stuff in bodies. Stuff ends up looking like red blobs sitting among a collection of red blobs).
It's very difficult to learn from a cadaver; A bunch of different structures in the book might just look like one big chunk in the body (cause maybe they're all enveloped and held together by connective tissue). Unlike a piece of designed equipment that needed to be assembled, everything space is stuffed and crammed with something or another, because it probably grew there. Except when it didn't grow there, it grew somewhere else and migrated. And because it was grown and not made, often it's not quite the shape or location that the book says.
As a result, learning to navigate around a body and recognize it's components is a special skill that goes far beyond memorizing those components themselves. There's a lot of reasoning and tracing connections and relationships. You don't just learn things from a cadaver, you learn skills.
Pentacene
I was thinking the same thing, organic substrates are so fragile. The lifespan problems involved are very much like those encountered in OLED material development, except even worse (due to the harsher usage conditions).
Ah, okies. I was Guppy on Midgardsormr / Guppeh on Quetzalcoatl (currently on hiatus). /panic !
Sandytaru, I was curious about your nickname. Do you by any chance play Final Fantasy XI?
Hopefully, this will also push for substitutions using less-toxic fracking fluid components, even if some of these components may be higher cost.
For instance (pulling hypothetical example out of my butt, no personal expertise in fracking fluid chemistry) a mineral-oil based carrier vs. a diesel-fuel carrier. I mean, the mechanical properties of the fracking fluid seem like the most important, right? So there should be some fungibility regarding exact chemistry used.
"As the Americans learned so painfully in Earth's final century, free flow of information is the only safeguard against tyranny. The once-chained people whose leaders at last lose their grip on information flow will soon burst with freedom and vitality, but the free nation gradually constricting its grip on public discourse has begun its rapid slide into despotism.
Beware of he who would deny you access to information, for in his heart he dreams himself your master."
--Pravin Lal
There's some rumors that external HDDs may not be the same as internal models, and that they use techniques such as "Shingle Writing" to trade reduced speed for larger storage sizes: http://www.theregister.co.uk/2010/07/12/adding_platters/page2.htmlshingle writing
If this is true, you might want to do some testing to make sure your drives perform as expected.