The stuff with a half life of 24,000 years is only very mildly radioactive. That is pretty much what "long half life" means. I'd be surprised if that plutonium wasn't more of a chemical hazard than a radioactivity hazard. GP says "the bulk of the radioactivity..." You can't invalidate that statement with examples of minor sources of radioactivity.
I see nothing inherently dangerous about nuclear reactors. We know sodium reactors don't go critical even when there's a total coolant failure.
Fukushima had a total coolant failure, and didn't go critical, but it was certainly dangerous. And there they had (and used) the option to pump cold water into the primary coolant loop and vent steam from it - an option which wouldn't be available with sodium.
Reprocessing fuel is in itself dangerous: the third worst nuclear accident was at a reprocessing plant. I suspect your analysis of waste reduction through reprocessing is highly optimistic, but I lack the expertise to say for sure.
That would be from anywhere on Earth with a high intensity particle accelerator to anywhere on Earth with a huge particle detector buried hundreds of metres underground.
IPOs and share issues help the economy, but nobody would buy these shares if there wasn't a way to recover the investment (hopefully with a profit) later. The only shares I own were purchased directly from the issuing company. (Which reminds me - it is over a year since I looked at their value. Crud - they're both doing horribly.)
The share market also provides a mechanism for takeovers and mergers.
Investing in shares for time spans of months is of general benefit to the economy, directing investment dollars to those best able to use them. Millisecond trading is of no benefit to anyone except millisecond traders, and any money they make is at the expense of people trying to do something productive. I propose that stock markets shift to a 'clock pulse' trading model: Trade bids for (e.g.) Apple are accumulated for (e.g.) 5 seconds and then all sales are resolved without regard for the order in which the bids arrived. This will cause no problems to real investors, but will rid us of the millisecond leaches.
However, I am not experienced with the share market, so constructive criticism is welcome.
The question "are these sufficiently different to be two species" is inherently a fuzzy one. We tend to be a bit more picky when dealing with our near relatives, so we might call these a different species when for two squirrel groups with a similar level of difference we might call them subspecies. I've seen it argued that an objective taxonomist would put humans, chimps and gorillas all in the same genus, we've classified this lineage into four - gorilla, pan, homo and (extinct) austalopithecus.
Can we sequence DNA from them? Probably, but not certainly. Ancient DNA is a very tricky business. The preservation of DNA depends a lot on the conditions they've been in since death. Cold and dry is ideal. I know we've sequenced DNA over 30,000 years old, I'm not sure what the record is.
Ancient human DNA is even trickier. If you're dealing with ancient bison DNA, you can largely avoid contamination problems by keeping the remains away from any modern bison. Keeping your human remains (and DNA samples extracted from them) away from modern humans isn't so easy. In this case, the cat is already out of the bag - the samples have been exposed to modern human DNA for decades. All is not lost, but it makes the job harder, and the outcome more open to doubt.
Can we clone them? Absolutely not with current technology. We can't clone a cow from a fresh steak, yet alone 10,000 year old bones. It is conceivable that future technology would allow it. I don't think you'll ever get it past an ethics committee though.
The fine article says that this result is extrapolated from microlensing survey results.
I have a peripheral connection with MOA myself. Phil Yock was my MSc cosupervisor (pre-MOA) and later I travelled to the telescope and helped with some setup, mostly of the computers. I also told them that I didn't think using "sleep 30" to control the exposure time was a good idea.
Slingshots are fine pottering around the solar system, where your ship speeds are comparable to your planet escape velocities. When you're travelling at over 1000 km/s, slingshotting past a 20km/s escape velocity planet does stuff-all for you.
If the planet is travelling at more than the escape speed from the galaxy, it won't be in the galaxy any more. If it travelling at less than this escape speed and your ship is travelling at the same speed, you're taking at least a couple of thousand years to get to the nearest star. (And this is all before considering the chances of finding such a fortuitously placed planet.)
(Orbital speed of the sun around galactic center = approx 220 km/s, on approx circular orbit. Escape velocity = sqrt(2)*circular orbit velocity = 310 km/s. 310km/s approx = speed of light/1000, which implies 4200 years to travel 4.2 light years. Actually, it is a little better than this: this formula assumes all the mass is inside the orbit of the sun. Accounting for the galactic mass outside the solar orbit will raise the escape velocity somewhat. But then you need to consider the planets velocity relative to the sun, which means we need to subtract a 220 km/s vector off its galaxy-centric velocity, and that will decrease the relative speed, because it has to be travelling vaguely parallel to the sun's motion to be of any use at all.)
This was my thought too. If you're going to reach the alpha Centauri system in under a thousand years, you need to be going faster than 1200 km/s. How do they propose to refuel from something they're passing at 1200 km/s? The alternative -- expending fuel to slow down, refuel, then expend fuel to get back to speed -- is more than a little self defeating.
Quantum mechanics, special relativity and general relativity are all very hard to learn, in part because they are so counterintuitive. Imagine a computer game which throws you into a universe where SR (or quantum mechanics or GR) have large, easily measurable effects - e.g. the speed of light is about 50m/s. After you've spent enough time zipping around on your relativistic motorcycle shooting zombies (or whatever), you should be able to intuitively understand SR, and the mathematics will become easy. (Well, as easy as Newtonian physics, anyhow.)
It isn't the number of people that die that determines whether it is worthwhile, it is the cost/benefit ratio. Fortunately, TFA provides some of the needed information, but it doesn't seem very consistent. "But regulators say that 95 to 112 deaths and as many as 8,374 injuries could be avoided each year by eliminating the wide blind spot behind a vehicle." (Compared to the 200/17000 numbers, it looks like they believe the cameras will about halve the number of accidents.) "...regulators predicted that adding the cameras and viewing screens will cost the auto industry as much as $2.7 billion a year, or $160 to $200 a vehicle." Wikipedia says 5.5 million vehicles sold in USA in 2009. (I presume this is new sales only.) This would imply about $500 per vehicle to reach $2.7 billion. "For the 2012 model year, 45 percent of vehicles offer a rearview camera as standard equipment." Is that 45% of vehicles sold, or 45% of models? If 45% of vehicles, then only 55% are going to have extra cost if the cameras are required.
Optimistic cost/benefit ratio: 112 deaths prevented per year, 55% of 5.5 million vehicles at $160 per vehicle = 484 million dollars per year = $4.3 million dollars to save one life and 75 injuries. (75=8374/112) Pessimistic cost/benefit ratio: 95 deaths prevented per year at a cost of $2.7 billion per year = $28 million to save one life and a bunch of injuries.
(Note that the cost is up-front, but the benefit is spread out over the ~10 year lifetime of the vehicle, which makes the investment a little less attractive, but I'm not trying to account for this.)
"The law, in its majestic equality, forbids the rich as well as the poor to sleep under bridges, to beg in the streets, and to steal bread." (La majestueuse égalité des lois, qui interdit au riche comme au pauvre de coucher sous les ponts, de mendier dans les rues et de voler du pain.)
That was a quick summary of history of science, not a pop-sci article explaining nearly neutral selection. The point is your argument was based on a false premise. Evolutionary biologists have for a very long time considered slightly deleterious mutations. Here's another example.
Lack of recombination is generally a Bad Thing, hence no other asymmetric pairs. So the questions are why does the X-Y system lead to asymmetry, and why do we have X-Y rather than a system which allows full symmetry (e.g. temperature dependent sex determination, as in many reptiles)?
While I'm sure it has been thought about, I don't know the answer to the first question. It seems quite viable to have a single sex determining gene (SRY in nearly all mammals) but still have full symmetry and recombination everywhere except in the middle of that particular gene. One possibility is that faulty male-specific genes (other than SRY) would not be selected against so strongly, as half the time they are in a female where the fault has no effect. With asymmetry this is not the case, so long as the gene has migrated to the Y chromosome.
The answer to the second question might simply be contingency of history: if we evolved from temperature-dependent sex determination, but became live-young-bearing-with-regulated-temperature, clearly a new sex determination method is needed, and maybe X-Y (or W-Z) was easier to evolve to than some other environmental selection method. It isn't hard to see how a gene affecting the threshold temperature in a temperature-dependent system could mutate into an XY or WZ system.
It just occurred to me that these two effects can be disentangled by looking at birds. The Z chromosome spends 2/3 of its time in males, so should evolve faster than normal (autosomal) chromosome, but it can recombine. The W spends 100% of its time in females, but has no recombination. The 'many times more sperm than ova therefore faster evolution (more errors) in males' may not hold for all animals, but it should hold for birds.
While I'm at it, I keep pointing out that a cophylogeny of mitochondria and W chromosomes could potentially measure the rate of 'paternal leakage' of mitochondria in a bird species, but so far as I know nobody has tried this.
They Y chromosome not only evolves fast because of lack of recombination, but also because sperm are very many more cell division generations away from the original copy (fertilized ovum) than ova are. The Y chromosome spends 100% of its time in males, normal chromosomes 50%, X chromosomes 33.3%.
Ref: "Male-Driven Sequence Evolution", pg 225, "Molecular Evolution" by Wen-Hsiung Li (1997).
Calm down, it is just a plant. There is no reason to expect it to be more dangerous than any one of millions of other plant species which are currently not taking over the world. It was around 30,000 years ago, and spectacularly failed to take over the world back then when it had the chance. The article notes that there is a very similar species (Silene stenophylla) which is around today, also not taking over the world.
The problem of replacing oil for transport is much smaller than the problem of replacing fossil fuels entirely. (Whether it is enough smaller remains to be seen.) Nobody is talking about relying on trees as fuel for power stations and steel refineries.
(Also, I don't think they deforested Europe like this - trees for charcoal were (or certainly could be) managed sustainably - it is just that supply could not keep up with growing demand as steel production increased.)
Slashdot Mirror
Yes, but 80% of the cost will go to the senior managers who are paid $1M/hour.
I'm anti-libertarian and I think it was reasonable to call this a troll. It was fine up to the sentence starting "I suppose..."
The stuff with a half life of 24,000 years is only very mildly radioactive. That is pretty much what "long half life" means. I'd be surprised if that plutonium wasn't more of a chemical hazard than a radioactivity hazard. GP says "the bulk of the radioactivity..." You can't invalidate that statement with examples of minor sources of radioactivity.
I see nothing inherently dangerous about nuclear reactors. We know sodium reactors don't go critical even when there's a total coolant failure.
Fukushima had a total coolant failure, and didn't go critical, but it was certainly dangerous. And there they had (and used) the option to pump cold water into the primary coolant loop and vent steam from it - an option which wouldn't be available with sodium.
Reprocessing fuel is in itself dangerous: the third worst nuclear accident was at a reprocessing plant. I suspect your analysis of waste reduction through reprocessing is highly optimistic, but I lack the expertise to say for sure.
That would be from anywhere on Earth with a high intensity particle accelerator to anywhere on Earth with a huge particle detector buried hundreds of metres underground.
IPOs and share issues help the economy, but nobody would buy these shares if there wasn't a way to recover the investment (hopefully with a profit) later. The only shares I own were purchased directly from the issuing company. (Which reminds me - it is over a year since I looked at their value. Crud - they're both doing horribly.)
The share market also provides a mechanism for takeovers and mergers.
Investing in shares for time spans of months is of general benefit to the economy, directing investment dollars to those best able to use them. Millisecond trading is of no benefit to anyone except millisecond traders, and any money they make is at the expense of people trying to do something productive. I propose that stock markets shift to a 'clock pulse' trading model: Trade bids for (e.g.) Apple are accumulated for (e.g.) 5 seconds and then all sales are resolved without regard for the order in which the bids arrived. This will cause no problems to real investors, but will rid us of the millisecond leaches.
However, I am not experienced with the share market, so constructive criticism is welcome.
The question "are these sufficiently different to be two species" is inherently a fuzzy one. We tend to be a bit more picky when dealing with our near relatives, so we might call these a different species when for two squirrel groups with a similar level of difference we might call them subspecies. I've seen it argued that an objective taxonomist would put humans, chimps and gorillas all in the same genus, we've classified this lineage into four - gorilla, pan, homo and (extinct) austalopithecus.
Can we sequence DNA from them? Probably, but not certainly. Ancient DNA is a very tricky business. The preservation of DNA depends a lot on the conditions they've been in since death. Cold and dry is ideal. I know we've sequenced DNA over 30,000 years old, I'm not sure what the record is.
Ancient human DNA is even trickier. If you're dealing with ancient bison DNA, you can largely avoid contamination problems by keeping the remains away from any modern bison. Keeping your human remains (and DNA samples extracted from them) away from modern humans isn't so easy. In this case, the cat is already out of the bag - the samples have been exposed to modern human DNA for decades. All is not lost, but it makes the job harder, and the outcome more open to doubt.
Can we clone them? Absolutely not with current technology. We can't clone a cow from a fresh steak, yet alone 10,000 year old bones. It is conceivable that future technology would allow it. I don't think you'll ever get it past an ethics committee though.
The fine article says that this result is extrapolated from microlensing survey results.
I have a peripheral connection with MOA myself. Phil Yock was my MSc cosupervisor (pre-MOA) and later I travelled to the telescope and helped with some setup, mostly of the computers. I also told them that I didn't think using "sleep 30" to control the exposure time was a good idea.
Slingshots are fine pottering around the solar system, where your ship speeds are comparable to your planet escape velocities. When you're travelling at over 1000 km/s, slingshotting past a 20km/s escape velocity planet does stuff-all for you.
If the planet is travelling at more than the escape speed from the galaxy, it won't be in the galaxy any more. If it travelling at less than this escape speed and your ship is travelling at the same speed, you're taking at least a couple of thousand years to get to the nearest star. (And this is all before considering the chances of finding such a fortuitously placed planet.)
(Orbital speed of the sun around galactic center = approx 220 km/s, on approx circular orbit. Escape velocity = sqrt(2)*circular orbit velocity = 310 km/s. 310km/s approx = speed of light/1000, which implies 4200 years to travel 4.2 light years. Actually, it is a little better than this: this formula assumes all the mass is inside the orbit of the sun. Accounting for the galactic mass outside the solar orbit will raise the escape velocity somewhat. But then you need to consider the planets velocity relative to the sun, which means we need to subtract a 220 km/s vector off its galaxy-centric velocity, and that will decrease the relative speed, because it has to be travelling vaguely parallel to the sun's motion to be of any use at all.)
This was my thought too. If you're going to reach the alpha Centauri system in under a thousand years, you need to be going faster than 1200 km/s. How do they propose to refuel from something they're passing at 1200 km/s? The alternative -- expending fuel to slow down, refuel, then expend fuel to get back to speed -- is more than a little self defeating.
Quantum mechanics, special relativity and general relativity are all very hard to learn, in part because they are so counterintuitive. Imagine a computer game which throws you into a universe where SR (or quantum mechanics or GR) have large, easily measurable effects - e.g. the speed of light is about 50m/s. After you've spent enough time zipping around on your relativistic motorcycle shooting zombies (or whatever), you should be able to intuitively understand SR, and the mathematics will become easy. (Well, as easy as Newtonian physics, anyhow.)
Single celled - check.
Size of a pancake - check.
Bacteria - no.
Two out of three isn't bad.
The library of congress can now fit onto 4 hard drives with room to spare. Assuming that number is uncompressed, one should do.
You can do your own web search for giant pancakes, it lacks sufficient challenge to be interesting.
It isn't the number of people that die that determines whether it is worthwhile, it is the cost/benefit ratio. Fortunately, TFA provides some of the needed information, but it doesn't seem very consistent.
"But regulators say that 95 to 112 deaths and as many as 8,374 injuries could be avoided each year by eliminating the wide blind spot behind a vehicle." (Compared to the 200/17000 numbers, it looks like they believe the cameras will about halve the number of accidents.)
"...regulators predicted that adding the cameras and viewing screens will cost the auto industry as much as $2.7 billion a year, or $160 to $200 a vehicle." Wikipedia says 5.5 million vehicles sold in USA in 2009. (I presume this is new sales only.) This would imply about $500 per vehicle to reach $2.7 billion.
"For the 2012 model year, 45 percent of vehicles offer a rearview camera as standard equipment." Is that 45% of vehicles sold, or 45% of models? If 45% of vehicles, then only 55% are going to have extra cost if the cameras are required.
Optimistic cost/benefit ratio: 112 deaths prevented per year, 55% of 5.5 million vehicles at $160 per vehicle = 484 million dollars per year = $4.3 million dollars to save one life and 75 injuries. (75=8374/112)
Pessimistic cost/benefit ratio: 95 deaths prevented per year at a cost of $2.7 billion per year = $28 million to save one life and a bunch of injuries.
(Note that the cost is up-front, but the benefit is spread out over the ~10 year lifetime of the vehicle, which makes the investment a little less attractive, but I'm not trying to account for this.)
"The law, in its majestic equality, forbids the rich as well as the poor to sleep under bridges, to beg in the streets, and to steal bread."
(La majestueuse égalité des lois, qui interdit au riche comme au pauvre de coucher sous les ponts, de mendier dans les rues et de voler du pain.)
Anatole France
That was a quick summary of history of science, not a pop-sci article explaining nearly neutral selection. The point is your argument was based on a false premise. Evolutionary biologists have for a very long time considered slightly deleterious mutations. Here's another example.
Evolutionists seem to think any non beneficial mutation results in a non reproducing/ non viable entity.
No we don't.
Lack of recombination is generally a Bad Thing, hence no other asymmetric pairs. So the questions are why does the X-Y system lead to asymmetry, and why do we have X-Y rather than a system which allows full symmetry (e.g. temperature dependent sex determination, as in many reptiles)?
While I'm sure it has been thought about, I don't know the answer to the first question. It seems quite viable to have a single sex determining gene (SRY in nearly all mammals) but still have full symmetry and recombination everywhere except in the middle of that particular gene. One possibility is that faulty male-specific genes (other than SRY) would not be selected against so strongly, as half the time they are in a female where the fault has no effect. With asymmetry this is not the case, so long as the gene has migrated to the Y chromosome.
The answer to the second question might simply be contingency of history: if we evolved from temperature-dependent sex determination, but became live-young-bearing-with-regulated-temperature, clearly a new sex determination method is needed, and maybe X-Y (or W-Z) was easier to evolve to than some other environmental selection method. It isn't hard to see how a gene affecting the threshold temperature in a temperature-dependent system could mutate into an XY or WZ system.
It just occurred to me that these two effects can be disentangled by looking at birds. The Z chromosome spends 2/3 of its time in males, so should evolve faster than normal (autosomal) chromosome, but it can recombine. The W spends 100% of its time in females, but has no recombination. The 'many times more sperm than ova therefore faster evolution (more errors) in males' may not hold for all animals, but it should hold for birds.
While I'm at it, I keep pointing out that a cophylogeny of mitochondria and W chromosomes could potentially measure the rate of 'paternal leakage' of mitochondria in a bird species, but so far as I know nobody has tried this.
They Y chromosome not only evolves fast because of lack of recombination, but also because sperm are very many more cell division generations away from the original copy (fertilized ovum) than ova are. The Y chromosome spends 100% of its time in males, normal chromosomes 50%, X chromosomes 33.3%.
Ref: "Male-Driven Sequence Evolution", pg 225, "Molecular Evolution" by Wen-Hsiung Li (1997).
No, monogamy is neither here nor there from an evolutionary view point, unless the gene pool is really tiny.
Calm down, it is just a plant. There is no reason to expect it to be more dangerous than any one of millions of other plant species which are currently not taking over the world. It was around 30,000 years ago, and spectacularly failed to take over the world back then when it had the chance. The article notes that there is a very similar species (Silene stenophylla) which is around today, also not taking over the world.
The problem of replacing oil for transport is much smaller than the problem of replacing fossil fuels entirely. (Whether it is enough smaller remains to be seen.) Nobody is talking about relying on trees as fuel for power stations and steel refineries.
(Also, I don't think they deforested Europe like this - trees for charcoal were (or certainly could be) managed sustainably - it is just that supply could not keep up with growing demand as steel production increased.)