Assume they are entangled in such a way that when you measure one to be up, you instantly know the other is down. Physicists will say, how could the other electron possibly know this, instantly. But a very simple explanation is that the device always shoots 1 up, 1 down.
It's a lot more complicated that that.
There are conjugate pairs of variables. For example your photon can be in state 1 or state 0 if you decide to measure it's numeric state but it can be in state A or state B if you decide to measure it's alphabetic state.
If you measure it's alphabetic state then you destroy all knowledge of any previous numeric state. So you measure 0, then you measure A, now when you go back to measure the numeric state it's 50/50 whether you get state 0 or state 1.
Entanglement means that our two photons give opposite results whether we measure their numeric or their alphabetic state.
So if we decide to measure numeric for both we get 0 for one and 1 for the other. But if we measure alphabetic for both we get A for one and B for the other.
Extending your idea we could think that the photon actually has "hidden variables" so that it does know the result of the measurement before it's made but something called Bell's inequality proves that hidden variables cannot be local.
The majority of humanity probably think posting something to facebook or whatever is similar to writing "Got totally plastered on holiday" on the back of a postcard and posting it to their local (something that people do)
Sure, it's public but after a few years it will have vanished without trace.
Plutonium is the most toxic substance known - even one atom will be harmful, even if not readily apparent.
Except that the facts don't agree with you.
Plutonium is a lot less toxic than something like dimethyl mercury.
It's definitely not something you should eat or inhale the dust but it's no more toxic than a lot of other substances, many of which are contact poisons.
Where you don't care about a determined attacker but want to stop a casual eavesdropper.
For example a blog where you want to require users to login. Stolen passwords are a pain but not a major issue but being able to stop people just sniffing them off unencrypted wifi connections makes sense.
Or want to stop ISPs seeing/hijacking pages to insert ads. Although ISPs could do a MITM attack on self signed certs, it's likely that before very long someone will notice an ISP doing it to one cert at which point people will very quickly see that it's happening to all of them.
Many (most?) SMTP servers will negotiate TLS with self signed (or non "official" CA signed certs) if it's available. It would be interesting to know how many email servers are setup to refuse to send if the cert cannot be verified. I'm sure there are some servers out there that do this (and they're probably only allowing manually installed CAs as well) but I expect they're few and far between.
Even between my home mail server that receives my mail and the backup mailserver I have if my home server is unavailable I forward using TLS (and the CA is installed) but I've not even considered bothering to block it if the certs don't match. If MI5 or the police decide they do want to intercept this mail then I probably wouldn't notice as the only visible symptom would be in the mailserver logs where it would no longer say the cert verified OK but someone at an ISP in the link is not going to accidentally start copying my mail traffic like google did with WIFI.
An unencrypted connection can be attacked at any point in time. A encrypted but unauthenticated connection can only be attacked while it is being set up.
And it isn't even possible for an attacker to tell when it is transparent to attack the key exchange and when the browser actually has the certificate or a plugin to warn that the certificate has changed.
Encrypted connections prevent passive eavesdroppers and force attackers to use active attacks which are detectable if you care enough to want to detect them.
What do you mean by "letting go"? Do you mean giving an object escape velocity from the earth?
I think he means reducing the gravitational mass while leaving the inertial mass unchanged.
It's a neat trick. Just stand on the equator, wait until you're moving in the direction you want to go into space and then just turn off gravity.
With appropriately timed switchings you can probably get into orbit with no additional energy expenditure. Wait until you're high enough and then turn gravity back on - you'll fall back towards the Earth. Turn it off again and you'll "slingshot". Repeat until orbital speed is reached.
Still not sure how you turn off gravity though. Something of a stumbling block.
I disagree. CDO's aren't the real problem. It's taking risky mortgages, with, for example, a long term rate of default expected at 50% and then saying that the best 20% of the risky mortgages cannot fail.
For a while we saw a default rate of sub 10%. That should immediately have raised alarm bells that the variance on the 50% is high. Instead more and more people started jumping on the "easy money" to the point where investors (as opposed to speculators) were buying things that, on average, were expected to lose money.
That, in turn, allowed the banks to raise more money, make more risky loans, and prop up the pyramid housing market for longer.
If the top tranch of the CDOs had been paying a realistic return related to the risk then the banks could not have made the risky loans at the very low rates they were using - and so would not have been able to make the loans in the first place as the people taking out the mortgages could not have afforded them.
The banks could only issue the CDOs with the low rates they were paying because the ratings agencies said they (the top tranches) were AAA grade. The ball could not have got rolling without that mistake.
Of course, the whole thing is muddied by the banks paying the ratings agencies to rate their CDOs and, no doubt the people designing the CDO tranches were working with the ratings agencies to design something that got an AAA rating.
The power is pretty meaningless provided the pulse is short enough, it's the energy delivered that matters.
You can get a low end estimate for the energy delivered by knowing the diameter and thickness of the hole.
From that you can work out the mass of steel that is vapourized.
The longer the pulse is the more time the heat has to dissipate until, eventually, the heat is conducted away so fast that you can't actually mark the steel at all.
I can't be bothered to look up the numbers but lets assume 400J/kgK SHC (about 1/10 that of water), boiling point deltaT approx 3000K
So we get approx 1.2MJ/Kg
Density of about 10.
0.1 mm cube of steel vapourized would then be about 0.1J
If the pulse is 100ns then that would correspond to a power of about 1MW.
Shortening the pulse to 1ns would up the power to 100MW but wouldn't make a significantly bigger hole because there isn't enough energy present. (I'm guessing that 100ns is already short enough that losing heat through conduction isn't a significant issue)
An USA landowner grows a particular type of wheat. He sells that wheat in USD to pay his workers in USD and make a profit.
A German biscuit maker makes a biscuit that he sells in EUR to pay his workers in EUR. So far everything is simple
The German biscuit maker needs to buy the particular wheat he uses from the USA landowner. But his incoming cash is in EUR while (some of) his expenses are now in USD.
The biscuit maker is now exposed to the USD/EUR exchange rate and the price of wheat. He wants to expand - if he expands too fast he'll run out of cash and be unable to buy the raw materials he needs. If he expands too slowly he'll be sitting on a pile of cash that is slowly deflating and doing nothing useful.
So he may buy futures/options on both the wheat and the FX to fix/cap his costs for next year. They he knows how much money he's got left to fund his expansion.
Even something as apparently straight forward as a package holiday might have many different players buying futures and options. The airline is likely to be buying futures for the fuel they're going to have to use. The holiday company may be hedging FX.
Then there are people who help make a market for the people who are interested. If the only way that German biscuit maker could fix his costs was to put an advert in the paper "hey, is there anyone expecting to receive 2MM USD in six months who will need EUR and wants to make a deal to swap it for 1.4MM EUR in the future" then he's probably going to have trouble finding someone who wants to make the deal. But instead there are dealers who will take the other side of the deal without really wanting the EUR (or the USD for that matter). Then they make other deals with other people, for example someone else might want to do the swap the other way but in seven months. So now they'll try and make yet another deal to hedge their exposure on that one month. At the end of the day (if everything works out rationally) they'll win some and lose some which will cancel out but they'll also have received the premium for setting up the deals that will be their profit. And everyone else is happy because they've fixed their FX costs and they can get on with running the business that they understand.
Where it starts going wrong is when something starts reliably moving one way and speculators start deliberately exposing themselves to the risk. The dealers above will almost certainly always have some exposure but it should be relatively small and controlled. Unfortunately, the dealers who have more exposure make more profit (and profit is king) and so you get a vicious cycle. Eventually there are so many people betting one way that there isn't enough demand for the underlying and the whole house of cards collapses.
(There was a brief moment - I think back in October 2006 - where the spot price for Natural Gas in the UK actually went negative - people who held futures to take delivery of gas had to pay someone else to take that gas off their hands)
Of course, the reality is that this attitude allows vendors to supply GUIs without any "unnecessary" manuals, but make the nested tree of windows and menus so deep and complex that nobody can ever remember where everything has been hidden, and there are no good tools to help you find something that you know is in there somewhere.
I think it's even worse than that.
If you have a problem to solve with a CLI then you might spend several days trying to make something work the way you need it to, but, once it's sorted it's very easy to document it for next time. (where next time might be several years down the line)
With GUI it's almost impossible to know what you've actually done at the time, let alone several years later.
Need to change a config file - take a copy, make changes, experiment etc. Once you've worked out what it is you actually need to to, restore the copy and then make the required changes. (Or just diff the original with the new version, "Hmmm, don't think I should have changed that setting, I'll change it back".)
With a GUI that "try this, try that" means that you have no idea what you might inadvertently/incorrectly have changed on your way to fixing the issue that you were really interested in.
And five years later when you need to do it again - CLI, all the options have changed subtly but your notes immediately give you a point to google and half an hour later you've worked out the correct set of switches to achieve what you need with the current version.
With the GUI, even if you've got perfect notes on what you did back then if it's even slightly non-obvious then it's very likely that the configuration option you need doesn't even exist any more (but no way to tell that of course).
I'm the same. In fact, possibly a useful technique for me would be to turn images into numbers and then remember the number. It's not something I've ever considered trying to do.
I can still remember the telephone numbers of my grandparents more than 20 years after they died (and so I can guarantee that I've never used them since).
I can remember things like my bank account numbers and sort codes. I don't have "speed dials" programmed into my telephone because I can remember the full telephone number of anyone I want to call more than a couple of times (and it's very useful when you can just borrow someone's phone)
Erdos is supposed to have had a phenomenal memory for numbers - he is recounted as having looked up half a dozen telephone numbers, then had a half hour or more conversation and only then ring the numbers he'd looked up earlier.
One of the numbers I am having problems remembering is my credit card number. About six months ago I lost my card and I'm still getting confused about the number when I use it on a website and have to fish the card out of my wallet to check - partly at least because the first six digits are the same between the old and new card and the old number I'd had for many years.
I play the piano but I have great difficulty playing from memory. In fact, the few pieces I have learned from memory have been more "muscle memory" rather than note memory - which is a problem - if you go wrong it's difficult to impossible to recover. It would be like remembering long numbers by the difference between each digit. If you get one digit wrong then the entire rest of the number will be wrong. My sight reading is reasonable compared to my overall ability (although much less good than I would like) which is probably a contributory factor to finding playing from memory difficult.
Currently, for five months of the year it's dark when I leave the house in the morning and it's dark when I get home at night.
There's no time more depressing than end October when the clocks go back. I've spent the previous few weeks going to work in the dark. Now I get to see the sun coming up on my way in (really useful NOT!) and I know I won't see the Sun in the evening until the clocks change again.
Moving the clocks by an hour will give me a brief interval in the evening where essential jobs can be done (sweeping up leaves, fixing dripping outdoor taps etc), freeing up time at the weekend that is currently wasted on those 15 minute jobs that _can't_ be done during the week.
Daylight in the evening is far more valuable than daylight in the morning even if your work hours are flexible. If your doing something messy in the garden then you can pack up as the Sun goes down and then shower and change inside when it's dark. Try to do it in the morning and you cannot start until the sun comes up and then you'll shower and change during daylight hours before leaving for work.
There is an argument that increasing the time difference with the States will affect some interactions. But OTOH, more overlap with the Far East will somewhat compensate for that.
Scotland can have its own timezone if that's what it wants. Perhaps companies that interact extensively with the States will relocate offices there as a result. It would take a little getting used to, especially for people who commute across the border to work but nothing insurmountable.
Summary: no need to crate a technological solution, just get up and go to work earlier!
Why is it that the people who oppose the clocks changing always come up with this "solution".
If you don't like the clocks changing then just go to work an hour later in summer or earlier in winter.
Most of the rest of us have jobs that are tied to wall time. In fact that's WHY the clocks change so that everyone who needs to changes together.
I've worked with people who are able to and do work "dawn to dusk", "making up" their hours in summer but the vast majority of people can't do 9 to 3 in winter and then 7 to 5 in summer.
I'm all in favour of going to CET. That way I might get to see the Sun for three more months of the year.
Niiiiiiice. $19 trillions just for the wind turbines (around 5M each), $100 trillions for the rooftop PV systems (around 60K each), but there is no economic issue. Right.
85 million bbl/day oil consumption (2007)
At $100 per bbl that's $8.5 billion per day or, by 2050 $120 trillion, almost exactly the same cost as you've given above.
Oil is less than $100/bbl now but is almost certainly going to be a lot more than $100/bbl by 2050 (unless, of course, we've switched most of our power generation to alternatives so that there's no longer the same demand)
Right now, migrating off oil is looking approximately economically neutral. There's a cashflow issue - if we do it over the next 40 years we're going to need about $3 trillion tied up in building new infrastructure (assuming it takes about 1 year from starting building to bringing something on line - dams are obviously slower, wind farms seem to be quicker). But the longer we leave it the more urgent it's going to become (eventually there will be a time when we have to be off oil) and the more cash we'll have to tie up in order to build the infrastructure more quickly.
It is possible that this is the reason behind some of the cold weather that the northern hemisphere has been experiencing this winter.
Anecdote but I'd not say that this winter has been cold. Other than a couple of weeks in December it's been remarkably warm in London.
I cycle to work. In the summer I wear a t-shirt. Autumn and spring I also put on a thin nylon reflective cape (mainly due to riding in the dark rather than for warmth). Winter (mid-late Nov through to some time in March) I usually need to wear an extra layer but this year I'm still in my "autumn" attire and it's only been those couple of weeks in December where I've put on an extra layer.
2) There is already more than enough CO2 for a 'full' greenhouse effect so more will not make it 'worse.' You are simply lying with this one. A 'full' greenhouse effect would mean that 100% of heat is retained. That's impossible, but you can look at worlds where heat retention is in the 99% range, such as Venus.
While I agree with your sentiments, and understand your frustration, your response to this just plain wrong.
Firstly you are correct that this is a lie. It's impossible to have a 'full' greenhouse effect. If you add more CO2 to a planet's atmosphere then its surface temperature will rise. The effect only "saturates" when the atmosphere is pure CO2 and there is so much that any attempt to add more causes an equal amount to bleed off into space. Even Venus is nowhere near this limit. (Venus' surface temperature may be at 99% of where it could theoretically get to - I've never seen anything that would support or refute this - which may be what your 99% refers to)
But '100% heat retained' is obviously complete bunkum.
At equilibrium, (and Venus is at equilibrium) the energy being radiated from the planet must match the energy being received from the Sun (ignoring any internally generated heat which is negligible)
Earth is not currently at equilibrium because we've dumped so much CO2 into the atmosphere so fast that the Earth is currently radiating less energy into space than it is receiving from the Sun and so is storing energy.
But if we were to stop increasing CO2 then eventually we'd return to a steady state. The surface would be warmer, not because we're trapping more energy than we were when there was less CO2 in the atmosphere but because the effective sphere where we radiate IR back into space is larger. Because it's larger it's at a higher altitude. Because temperatures drop with altitude, the surface has to get warmer so that the temperature at that effective sphere is high enough to radiate enough heat to balance what we're receiving from the Sun.
(This incidentally, is closely related to one of those emails that the septics jumped on - we don't currently have good numbers for the energy budget being received from the Sun and the energy budget being radiated back into space. It's a travesty that we don't have this data - it would give a much better bound on how far out of equilibrium we really are and what sort of surface temperature rise we could expect if we stopped producing more CO2.)
If I call up one of my friends I'll know pretty quickly if it's not really them. If I call up someone I don't know then I don't see that there is any great benefit in knowing that some other random company says that this random person that I don't know really is a random person that I don't know - the main benefit will be that if I call them more than once then I can confirm that I'm talking to the same person.
Certificate revocation is slightly different, but even then you don't really need a central authority - you merely need some known places where you can go to check if a certificate has been revoked and they just share any revocations that they've received.
Firefox's model is so broken with regards to certificates. I have to permanently accept a certificate before I've seen the site I'm visiting. Unverified HTTPS certificates should be treated exactly like HTTP connections but with the extra ability to be able to say "Yes, this is the right site this time, please warn me if someone might be spoofing it in the future" (Konqueror is only slightly better, at least it has "accept this certificate for this session only" but still doesn't have an easy way to make that acceptance permanent after seeing the site)
It's really bizarre how most people seem to get this backwards and want to be able to offload their trust onto someone else. Even the British Government do (did[1]) it. I have a user name and password to access the UK government stuff, mainly to do my tax return each year. I could, if I wanted, create a client certificate to do this. However, in order for the British Government to accept a client certificate it has to be signed by BT, a company I have no relationship at all with - quite how the British government thinks BT is more likely to know who I am than they are is completely beyond me.
Tim.
[1] I looked into this years ago when tax returns first went online. It may have changed now.
If it was perturbed into a slightly lower orbit then it would orbit the Earth in less than 24hrs. If it ended up in a slightly higher orbit then it would orbit the Earth in slightly more than 24 hrs.
I don't want to commit to which way this satellite has gone (because I'm bound to get it backwards) but it's now about 2 hours displaced from where it should have been. That's an error in its orbit of about 0.02% or about 20 seconds per day.
I have to say I wasn't aware that "placebos work even without deception" was new but perhaps this is the first rigorously controlled trial.
I've seen stuff before like "What should you tell your patient?" with suggestions like:
"Nobody understands why it works but in one in three cases, just taking one of these sugar pills three times a day can help with the symptoms."
For that matter, "Nobody understands why it works but in one in three cases, taking homeopathic remedies helps with the symptoms" ought to be equally valid, especially for things like chronic pain where conventional medicine doesn't really have an answer and is just used to mask the symptoms. If homeopathy works for someone then it's almost certainly a better option than morphine.
The main objection to homeopathy is that some people recommend it over conventional therapy that is known to be both required and effective in treating the particular problem.
Alternative remedies 'dangerous' for kids says report
"In 30 cases, the issues were "probably or definitely" related to complementary medicine, and in 17 the patient was regarded as being harmed by a failure to use conventional medicine.
"The report says that all four deaths resulted from a failure to use conventional medicine."
>And most of the time, you're bugging me for something you should be able to find for yourself in the documentation or something you should be doing yourself.
"It's just quicker if I ask you, thus saving the company time."
One of the ways some people can actually have negative productivity.
Did you read the article? It said exactly that increased levels of CO2 will be mitigated by increased growth of green plant life, and that the current models are too aggressive in their estimations of negative effects.
I don't think you understood my post.
I am saying that humans and the ecology they have survived in has maintained a stable 280ppm CO2 for tens of thousands of years. It's highly likely that the last time the CO2 level was as high as it is now was before there were hominids on Earth.
I am saying, therefore, that we need extraordinary evidence that it is safe before we start deliberately and consciously making massive changes to our environment and just because we got away with some stuff doesn't mean that we can get away with more.
This paper is a step on the way to saying that "Dumping CO2 into the atmosphere might not be quite as dire as we thought it was going to be but it's still going to have pretty serious climatic impacts. We may have a little more time to adapt to any changes."
That's a long way from saying "It's ok, we can continue dumping CO2 in the atmosphere without concern" which is what the "business as usual" crowd are claiming.
We started dumping CO2 into the atmosphere through ignorance. It wasn't until the late 1940s that the last of the uncertainties about whether increased CO2 was really going to warm the Earth's surface were finally put to rest and not until the 70s until we were sure that warming due to CO2 would swamp any cooling caused by aerosols, especially on the decadal time scale.
But we've had 40 years now of _knowing_ that CO2 is a potentially dangerous thing to be adding to the atmosphere. Despite that, we haven't even managed to stop our emissions growing, let alone getting them to the point where the environment can absorb our output.
I don't have children, I won't have children, and it's unlikely that I'll live long enough to see catastrophic climate change even if the worst (realistic) projections happen. But it really bugs me that humans are racing to extinction like lemmings "well, that step didn't kill me so a few more can't hurt either."
Life will survive us. I have dreams that humans will conquer the galaxy, maybe even the universe. But on current showing we're unlikely to even conquer our own stupidity.
I've got a better idea. If an economy of trillions of dollars is threatened by something which has not been proven, then those doing the threatening should bear the burden of proof.
(Or, as a famous environmentalist once said, "Extraordinary claims require extraordinary proof.")
Absolutely. The safety of burning oil the way we do is predicated on adding huge amounts of CO2 to the atmosphere will have no detrimental effect on climate.
We've known since Fourier and Arrhenius that on its own increasing CO2 will cause the Earth's surface temperature to increase.
The ball is now in the oil industry's court to prove that there really are feedbacks that will eliminate the negative effects. Unfortunately, the evidence accrues daily that indicates that, if anything, the scientists have been too conservative in their estimations of negative effects.
The brazillian was NOT a tourist, he was an illegal alien who ran from the police trying to make an arrest. But I suppose "criminal fleeing from armed police and failing to respond to a stop order gets shot" isn't in line with your bleeding heart.
"Fleeing from armed police" means "sitting on a tube train" "Illegal alien" means "Was here legally"
I'm amazed you didn't also mention "jumped over barriers" means "stopped to pick up a metro on the way into the station" "Wearing heavy clothing" means "wearing a denim jacket"
You really were taken in by the police lies weren't you.
And it's so convenient that the CCTV in the tube train just happened to stop working when this happens which allowed all these lies to be promulgated.
Slashdot Mirror
Assume they are entangled in such a way that when you measure one to be up, you instantly know the other is down. Physicists will say, how could the other electron possibly know this, instantly. But a very simple explanation is that the device always shoots 1 up, 1 down.
It's a lot more complicated that that.
There are conjugate pairs of variables. For example your photon can be in state 1 or state 0 if you decide to measure it's numeric state but it can be in state A or state B if you decide to measure it's alphabetic state.
If you measure it's alphabetic state then you destroy all knowledge of any previous numeric state. So you measure 0, then you measure A, now when you go back to measure the numeric state it's 50/50 whether you get state 0 or state 1.
Entanglement means that our two photons give opposite results whether we measure their numeric or their alphabetic state.
So if we decide to measure numeric for both we get 0 for one and 1 for the other. But if we measure alphabetic for both we get A for one and B for the other.
Extending your idea we could think that the photon actually has "hidden variables" so that it does know the result of the measurement before it's made but something called Bell's inequality proves that hidden variables cannot be local.
Tim.
The majority of humanity probably think posting something to facebook or whatever is similar to writing "Got totally plastered on holiday" on the back of a postcard and posting it to their local (something that people do)
Sure, it's public but after a few years it will have vanished without trace.
Tim.
Plutonium is the most toxic substance known - even one atom will be harmful, even if not readily apparent.
Except that the facts don't agree with you.
Plutonium is a lot less toxic than something like dimethyl mercury.
It's definitely not something you should eat or inhale the dust but it's no more toxic than a lot of other substances, many of which are contact poisons.
Tim.
Where you don't care about a determined attacker but want to stop a casual eavesdropper.
For example a blog where you want to require users to login. Stolen passwords are a pain but not a major issue but being able to stop people just sniffing them off unencrypted wifi connections makes sense.
Or want to stop ISPs seeing/hijacking pages to insert ads. Although ISPs could do a MITM attack on self signed certs, it's likely that before very long someone will notice an ISP doing it to one cert at which point people will very quickly see that it's happening to all of them.
Many (most?) SMTP servers will negotiate TLS with self signed (or non "official" CA signed certs) if it's available. It would be interesting to know how many email servers are setup to refuse to send if the cert cannot be verified. I'm sure there are some servers out there that do this (and they're probably only allowing manually installed CAs as well) but I expect they're few and far between.
Even between my home mail server that receives my mail and the backup mailserver I have if my home server is unavailable I forward using TLS (and the CA is installed) but I've not even considered bothering to block it if the certs don't match. If MI5 or the police decide they do want to intercept this mail then I probably wouldn't notice as the only visible symptom would be in the mailserver logs where it would no longer say the cert verified OK but someone at an ISP in the link is not going to accidentally start copying my mail traffic like google did with WIFI.
Tim.
This just isn't true.
An unencrypted connection can be attacked at any point in time. A encrypted but unauthenticated connection can only be attacked while it is being set up.
And it isn't even possible for an attacker to tell when it is transparent to attack the key exchange and when the browser actually has the certificate or a plugin to warn that the certificate has changed.
Encrypted connections prevent passive eavesdroppers and force attackers to use active attacks which are detectable if you care enough to want to detect them.
Tim.
What do you mean by "letting go"? Do you mean giving an object escape velocity from the earth?
I think he means reducing the gravitational mass while leaving the inertial mass unchanged.
It's a neat trick. Just stand on the equator, wait until you're moving in the direction you want to go into space and then just turn off gravity.
With appropriately timed switchings you can probably get into orbit with no additional energy expenditure. Wait until you're high enough and then turn gravity back on - you'll fall back towards the Earth. Turn it off again and you'll "slingshot". Repeat until orbital speed is reached.
Still not sure how you turn off gravity though. Something of a stumbling block.
Tim.
I disagree. CDO's aren't the real problem. It's taking risky mortgages, with, for example, a long term rate of default expected at 50% and then saying that the best 20% of the risky mortgages cannot fail.
For a while we saw a default rate of sub 10%. That should immediately have raised alarm bells that the variance on the 50% is high. Instead more and more people started jumping on the "easy money" to the point where investors (as opposed to speculators) were buying things that, on average, were expected to lose money.
That, in turn, allowed the banks to raise more money, make more risky loans, and prop up the pyramid housing market for longer.
If the top tranch of the CDOs had been paying a realistic return related to the risk then the banks could not have made the risky loans at the very low rates they were using - and so would not have been able to make the loans in the first place as the people taking out the mortgages could not have afforded them.
The banks could only issue the CDOs with the low rates they were paying because the ratings agencies said they (the top tranches) were AAA grade. The ball could not have got rolling without that mistake.
Of course, the whole thing is muddied by the banks paying the ratings agencies to rate their CDOs and, no doubt the people designing the CDO tranches were working with the ratings agencies to design something that got an AAA rating.
Tim.
The power is pretty meaningless provided the pulse is short enough, it's the energy delivered that matters.
You can get a low end estimate for the energy delivered by knowing the diameter and thickness of the hole.
From that you can work out the mass of steel that is vapourized.
The longer the pulse is the more time the heat has to dissipate until, eventually, the heat is conducted away so fast that you can't actually mark the steel at all.
I can't be bothered to look up the numbers but lets assume 400J/kgK SHC (about 1/10 that of water), boiling point deltaT approx 3000K
So we get approx 1.2MJ/Kg
Density of about 10.
0.1 mm cube of steel vapourized would then be about 0.1J
If the pulse is 100ns then that would correspond to a power of about 1MW.
Shortening the pulse to 1ns would up the power to 100MW but wouldn't make a significantly bigger hole because there isn't enough energy present. (I'm guessing that 100ns is already short enough that losing heat through conduction isn't a significant issue)
Tim.
An USA landowner grows a particular type of wheat. He sells that wheat in USD to pay his workers in USD and make a profit.
A German biscuit maker makes a biscuit that he sells in EUR to pay his workers in EUR. So far everything is simple
The German biscuit maker needs to buy the particular wheat he uses from the USA landowner. But his incoming cash is in EUR while (some of) his expenses are now in USD.
The biscuit maker is now exposed to the USD/EUR exchange rate and the price of wheat. He wants to expand - if he expands too fast he'll run out of cash and be unable to buy the raw materials he needs. If he expands too slowly he'll be sitting on a pile of cash that is slowly deflating and doing nothing useful.
So he may buy futures/options on both the wheat and the FX to fix/cap his costs for next year. They he knows how much money he's got left to fund his expansion.
Even something as apparently straight forward as a package holiday might have many different players buying futures and options. The airline is likely to be buying futures for the fuel they're going to have to use. The holiday company may be hedging FX.
Then there are people who help make a market for the people who are interested. If the only way that German biscuit maker could fix his costs was to put an advert in the paper "hey, is there anyone expecting to receive 2MM USD in six months who will need EUR and wants to make a deal to swap it for 1.4MM EUR in the future" then he's probably going to have trouble finding someone who wants to make the deal. But instead there are dealers who will take the other side of the deal without really wanting the EUR (or the USD for that matter). Then they make other deals with other people, for example someone else might want to do the swap the other way but in seven months. So now they'll try and make yet another deal to hedge their exposure on that one month. At the end of the day (if everything works out rationally) they'll win some and lose some which will cancel out but they'll also have received the premium for setting up the deals that will be their profit. And everyone else is happy because they've fixed their FX costs and they can get on with running the business that they understand.
Where it starts going wrong is when something starts reliably moving one way and speculators start deliberately exposing themselves to the risk. The dealers above will almost certainly always have some exposure but it should be relatively small and controlled. Unfortunately, the dealers who have more exposure make more profit (and profit is king) and so you get a vicious cycle. Eventually there are so many people betting one way that there isn't enough demand for the underlying and the whole house of cards collapses.
(There was a brief moment - I think back in October 2006 - where the spot price for Natural Gas in the UK actually went negative - people who held futures to take delivery of gas had to pay someone else to take that gas off their hands)
Tim.
Of course, the reality is that this attitude allows vendors to supply GUIs without any "unnecessary" manuals, but make the nested tree of windows and menus so deep and complex that nobody can ever remember where everything has been hidden, and there are no good tools to help you find something that you know is in there somewhere.
I think it's even worse than that.
If you have a problem to solve with a CLI then you might spend several days trying to make something work the way you need it to, but, once it's sorted it's very easy to document it for next time. (where next time might be several years down the line)
With GUI it's almost impossible to know what you've actually done at the time, let alone several years later.
Need to change a config file - take a copy, make changes, experiment etc. Once you've worked out what it is you actually need to to, restore the copy and then make the required changes. (Or just diff the original with the new version, "Hmmm, don't think I should have changed that setting, I'll change it back".)
With a GUI that "try this, try that" means that you have no idea what you might inadvertently/incorrectly have changed on your way to fixing the issue that you were really interested in.
And five years later when you need to do it again - CLI, all the options have changed subtly but your notes immediately give you a point to google and half an hour later you've worked out the correct set of switches to achieve what you need with the current version.
With the GUI, even if you've got perfect notes on what you did back then if it's even slightly non-obvious then it's very likely that the configuration option you need doesn't even exist any more (but no way to tell that of course).
Tim.
I'm the same. In fact, possibly a useful technique for me would be to turn images into numbers and then remember the number. It's not something I've ever considered trying to do.
I can still remember the telephone numbers of my grandparents more than 20 years after they died (and so I can guarantee that I've never used them since).
I can remember things like my bank account numbers and sort codes. I don't have "speed dials" programmed into my telephone because I can remember the full telephone number of anyone I want to call more than a couple of times (and it's very useful when you can just borrow someone's phone)
Erdos is supposed to have had a phenomenal memory for numbers - he is recounted as having looked up half a dozen telephone numbers, then had a half hour or more conversation and only then ring the numbers he'd looked up earlier.
One of the numbers I am having problems remembering is my credit card number. About six months ago I lost my card and I'm still getting confused about the number when I use it on a website and have to fish the card out of my wallet to check - partly at least because the first six digits are the same between the old and new card and the old number I'd had for many years.
I play the piano but I have great difficulty playing from memory. In fact, the few pieces I have learned from memory have been more "muscle memory" rather than note memory - which is a problem - if you go wrong it's difficult to impossible to recover. It would be like remembering long numbers by the difference between each digit. If you get one digit wrong then the entire rest of the number will be wrong. My sight reading is reasonable compared to my overall ability (although much less good than I would like) which is probably a contributory factor to finding playing from memory difficult.
Tim.
Just, you know, some of us don't want to go to work in the dark.
Just, you know, some of use don't like going to work AND coming home from work in the dark.
what on Earth is wrong with living in a time zone that reflects your physical location on the globe?
The working day is wrong. 9-5 gives three hours before noon and 5 hours after. Making solar noon 1pm wall time makes the working day symmetrical.
A 9-5:30 day which is common makes it even worse.
So make it 1 hour difference in winter when there are few daylight hours to play with and 2 hours in summer. Simple really.
people seem to forget that the "extra" hour is just being stolen from the other end of the day!
I'm all for stealing an hour of daylight from one end of the day so that I get to see the Sun at the other end.
Tim.
But it does give me more USABLE daylight.
Currently, for five months of the year it's dark when I leave the house in the morning and it's dark when I get home at night.
There's no time more depressing than end October when the clocks go back. I've spent the previous few weeks going to work in the dark. Now I get to see the sun coming up on my way in (really useful NOT!) and I know I won't see the Sun in the evening until the clocks change again.
Moving the clocks by an hour will give me a brief interval in the evening where essential jobs can be done (sweeping up leaves, fixing dripping outdoor taps etc), freeing up time at the weekend that is currently wasted on those 15 minute jobs that _can't_ be done during the week.
Daylight in the evening is far more valuable than daylight in the morning even if your work hours are flexible. If your doing something messy in the garden then you can pack up as the Sun goes down and then shower and change inside when it's dark. Try to do it in the morning and you cannot start until the sun comes up and then you'll shower and change during daylight hours before leaving for work.
There is an argument that increasing the time difference with the States will affect some interactions. But OTOH, more overlap with the Far East will somewhat compensate for that.
Scotland can have its own timezone if that's what it wants. Perhaps companies that interact extensively with the States will relocate offices there as a result. It would take a little getting used to, especially for people who commute across the border to work but nothing insurmountable.
Tim.
Summary: no need to crate a technological solution, just get up and go to work earlier!
Why is it that the people who oppose the clocks changing always come up with this "solution".
If you don't like the clocks changing then just go to work an hour later in summer or earlier in winter.
Most of the rest of us have jobs that are tied to wall time. In fact that's WHY the clocks change so that everyone who needs to changes together.
I've worked with people who are able to and do work "dawn to dusk", "making up" their hours in summer but the vast majority of people can't do 9 to 3 in winter and then 7 to 5 in summer.
I'm all in favour of going to CET. That way I might get to see the Sun for three more months of the year.
Tim.
Niiiiiiice. $19 trillions just for the wind turbines (around 5M each), $100 trillions for the rooftop PV systems (around 60K each), but there is no economic issue. Right.
85 million bbl/day oil consumption (2007)
At $100 per bbl that's $8.5 billion per day or, by 2050 $120 trillion, almost exactly the same cost as you've given above.
Oil is less than $100/bbl now but is almost certainly going to be a lot more than $100/bbl by 2050 (unless, of course, we've switched most of our power generation to alternatives so that there's no longer the same demand)
Right now, migrating off oil is looking approximately economically neutral. There's a cashflow issue - if we do it over the next 40 years we're going to need about $3 trillion tied up in building new infrastructure (assuming it takes about 1 year from starting building to bringing something on line - dams are obviously slower, wind farms seem to be quicker). But the longer we leave it the more urgent it's going to become (eventually there will be a time when we have to be off oil) and the more cash we'll have to tie up in order to build the infrastructure more quickly.
Tim.
It is possible that this is the reason behind some of the cold weather that the northern hemisphere has been experiencing this winter.
Anecdote but I'd not say that this winter has been cold. Other than a couple of weeks in December it's been remarkably warm in London.
I cycle to work. In the summer I wear a t-shirt. Autumn and spring I also put on a thin nylon reflective cape (mainly due to riding in the dark rather than for warmth). Winter (mid-late Nov through to some time in March) I usually need to wear an extra layer but this year I'm still in my "autumn" attire and it's only been those couple of weeks in December where I've put on an extra layer.
Tim.
While I agree with your sentiments, and understand your frustration, your response to this just plain wrong.
Firstly you are correct that this is a lie. It's impossible to have a 'full' greenhouse effect. If you add more CO2 to a planet's atmosphere then its surface temperature will rise. The effect only "saturates" when the atmosphere is pure CO2 and there is so much that any attempt to add more causes an equal amount to bleed off into space. Even Venus is nowhere near this limit. (Venus' surface temperature may be at 99% of where it could theoretically get to - I've never seen anything that would support or refute this - which may be what your 99% refers to)
But '100% heat retained' is obviously complete bunkum.
At equilibrium, (and Venus is at equilibrium) the energy being radiated from the planet must match the energy being received from the Sun (ignoring any internally generated heat which is negligible)
Earth is not currently at equilibrium because we've dumped so much CO2 into the atmosphere so fast that the Earth is currently radiating less energy into space than it is receiving from the Sun and so is storing energy.
But if we were to stop increasing CO2 then eventually we'd return to a steady state. The surface would be warmer, not because we're trapping more energy than we were when there was less CO2 in the atmosphere but because the effective sphere where we radiate IR back into space is larger. Because it's larger it's at a higher altitude. Because temperatures drop with altitude, the surface has to get warmer so that the temperature at that effective sphere is high enough to radiate enough heat to balance what we're receiving from the Sun.
(This incidentally, is closely related to one of those emails that the septics jumped on - we don't currently have good numbers for the energy budget being received from the Sun and the energy budget being radiated back into space. It's a travesty that we don't have this data - it would give a much better bound on how far out of equilibrium we really are and what sort of surface temperature rise we could expect if we stopped producing more CO2.)
Tim.
Why do you need a certificate authority?
If I call up one of my friends I'll know pretty quickly if it's not really them. If I call up someone I don't know then I don't see that there is any great benefit in knowing that some other random company says that this random person that I don't know really is a random person that I don't know - the main benefit will be that if I call them more than once then I can confirm that I'm talking to the same person.
Certificate revocation is slightly different, but even then you don't really need a central authority - you merely need some known places where you can go to check if a certificate has been revoked and they just share any revocations that they've received.
Firefox's model is so broken with regards to certificates. I have to permanently accept a certificate before I've seen the site I'm visiting. Unverified HTTPS certificates should be treated exactly like HTTP connections but with the extra ability to be able to say "Yes, this is the right site this time, please warn me if someone might be spoofing it in the future" (Konqueror is only slightly better, at least it has "accept this certificate for this session only" but still doesn't have an easy way to make that acceptance permanent after seeing the site)
It's really bizarre how most people seem to get this backwards and want to be able to offload their trust onto someone else. Even the British Government do (did[1]) it. I have a user name and password to access the UK government stuff, mainly to do my tax return each year. I could, if I wanted, create a client certificate to do this. However, in order for the British Government to accept a client certificate it has to be signed by BT, a company I have no relationship at all with - quite how the British government thinks BT is more likely to know who I am than they are is completely beyond me.
Tim.
[1] I looked into this years ago when tax returns first went online. It may have changed now.
If it was perturbed into a slightly lower orbit then it would orbit the Earth in less than 24hrs. If it ended up in a slightly higher orbit then it would orbit the Earth in slightly more than 24 hrs.
I don't want to commit to which way this satellite has gone (because I'm bound to get it backwards) but it's now about 2 hours displaced from where it should have been. That's an error in its orbit of about 0.02% or about 20 seconds per day.
Tim.
Don't understand your comment.
I have to say I wasn't aware that "placebos work even without deception" was new but perhaps this is the first rigorously controlled trial.
I've seen stuff before like "What should you tell your patient?" with suggestions like:
"Nobody understands why it works but in one in three cases, just taking one of these sugar pills three times a day can help with the symptoms."
For that matter, "Nobody understands why it works but in one in three cases, taking homeopathic remedies helps with the symptoms" ought to be equally valid, especially for things like chronic pain where conventional medicine doesn't really have an answer and is just used to mask the symptoms. If homeopathy works for someone then it's almost certainly a better option than morphine.
The main objection to homeopathy is that some people recommend it over conventional therapy that is known to be both required and effective in treating the particular problem.
Article on BBC today: http://www.bbc.co.uk/news/health-12060507
Alternative remedies 'dangerous' for kids says report
"In 30 cases, the issues were "probably or definitely" related to complementary medicine, and in 17 the patient was regarded as being harmed by a failure to use conventional medicine.
"The report says that all four deaths resulted from a failure to use conventional medicine."
Tim.
One of the ways some people can actually have negative productivity.
Tim.
Failed code review.
if (Password == "JOSHUA5")
^
Tim.
Did you read the article? It said exactly that increased levels of CO2 will be mitigated by increased growth of green plant life, and that the current models are too aggressive in their estimations of negative effects.
I don't think you understood my post.
I am saying that humans and the ecology they have survived in has maintained a stable 280ppm CO2 for tens of thousands of years. It's highly likely that the last time the CO2 level was as high as it is now was before there were hominids on Earth.
I am saying, therefore, that we need extraordinary evidence that it is safe before we start deliberately and consciously making massive changes to our environment and just because we got away with some stuff doesn't mean that we can get away with more.
This paper is a step on the way to saying that "Dumping CO2 into the atmosphere might not be quite as dire as we thought it was going to be but it's still going to have pretty serious climatic impacts. We may have a little more time to adapt to any changes."
That's a long way from saying "It's ok, we can continue dumping CO2 in the atmosphere without concern" which is what the "business as usual" crowd are claiming.
We started dumping CO2 into the atmosphere through ignorance. It wasn't until the late 1940s that the last of the uncertainties about whether increased CO2 was really going to warm the Earth's surface were finally put to rest and not until the 70s until we were sure that warming due to CO2 would swamp any cooling caused by aerosols, especially on the decadal time scale.
But we've had 40 years now of _knowing_ that CO2 is a potentially dangerous thing to be adding to the atmosphere. Despite that, we haven't even managed to stop our emissions growing, let alone getting them to the point where the environment can absorb our output.
I don't have children, I won't have children, and it's unlikely that I'll live long enough to see catastrophic climate change even if the worst (realistic) projections happen. But it really bugs me that humans are racing to extinction like lemmings "well, that step didn't kill me so a few more can't hurt either."
Life will survive us. I have dreams that humans will conquer the galaxy, maybe even the universe. But on current showing we're unlikely to even conquer our own stupidity.
Tim.
I've got a better idea. If an economy of trillions of dollars is threatened by something which has not been proven, then those doing the threatening should bear the burden of proof.
(Or, as a famous environmentalist once said, "Extraordinary claims require extraordinary proof.")
Absolutely. The safety of burning oil the way we do is predicated on adding huge amounts of CO2 to the atmosphere will have no detrimental effect on climate.
We've known since Fourier and Arrhenius that on its own increasing CO2 will cause the Earth's surface temperature to increase.
The ball is now in the oil industry's court to prove that there really are feedbacks that will eliminate the negative effects. Unfortunately, the evidence accrues daily that indicates that, if anything, the scientists have been too conservative in their estimations of negative effects.
Tim.
The brazillian was NOT a tourist, he was an illegal alien who ran from the police trying to make an arrest. But I suppose "criminal fleeing from armed police and failing to respond to a stop order gets shot" isn't in line with your bleeding heart.
"Fleeing from armed police" means "sitting on a tube train"
"Illegal alien" means "Was here legally"
I'm amazed you didn't also mention
"jumped over barriers" means "stopped to pick up a metro on the way into the station"
"Wearing heavy clothing" means "wearing a denim jacket"
You really were taken in by the police lies weren't you.
And it's so convenient that the CCTV in the tube train just happened to stop working when this happens which allowed all these lies to be promulgated.
Tim.