It's one thing to vibrate a broomstick in that manner, and quite another to do so with a 36,000 km space elevator. No matter what material you're using, you're looking at a very large mass; wikipedia estimates "a minimal, very low payload space elevator 'seed ribbon' could have a mass of at least 18,000 kg." -- or just shy of 20 tons. For hauling passengers and goods, you'll need much more. Now, we're talking about accelerating and decelerating this mass of at least 20 tons multiple times per second.
Not if the pulse is a travelling wave rather than a standing wave. Think of the cable as an enormous slinky. There's no need to vibrate all the mass at once.
The climber is going to have to be pretty intelligent though otherwise the lowest climber is going to steal all the energy and the one above it is going to get stuck until it gets rammed by the lowest climber.
You could have lots of climbers on the cable, at any point one is going down and the one below is going up - the higher one sends a pulse down the cable to power the one coming up. When they meet you transfer the payload (Or if they're on opposite sides of the cable they can pass).
In the ideal limit you get to the point where the only energy input at the bottom is that necessary to raise the payload. And carrying lots of radiation shielding on the climbers becomes less of an issue (so long as the cable is strong enough).
Your point about the energy is spot-on. Additionally, this concept totally ignores the orbiting anchor for the space elevator. For every 'yank' performed on the cable, you pull the anchor lower in orbit. The anchor then has to reposition itself USING ENERGY. Probably rocket fuel, I'd imagine. Either that, or the anchor releases the cable to allow it to go downwards, then has to pull it up again. That's the "lift" for the elevator- the pulling up of the cable.
I've not thought carefully about this but I'd think the whole point was that the orbiting mass was pulled lower. It's going to keep its same tangential velocity so it will then pull the cable up, then you yank the mass a bit lower, then it pulls the cable higher etc. In fact, in the extreme you could put the mass into an elliptical orbit although that would only give you one "jerk" per 24 hours and then you would just need to supply enough energy to the end of the cable to remove the losses from the climber. For a sufficiently large mass at the end you'll probably suffice with taking some rocket fuel up with a climber every now and again and boosting the mass to a higher orbit.
(I can vaguely see how this would work with a rigid cable. What happens with a real cable I'm not sure. I'd worry about stationary points forming - much like if you try and use a long washing line as a skipping rope it's quite hard to get the whole thing as a single half wave with nodes only at the ends.)
Or they'll sharpen points on their knives themselves. It's not hard.
But that's simply not true. There are enough crimes of passion that people would never stop in the middle of to fabricate a weapon. That alone would save lives. I'm not saying it's a worthy justification, but it simply isn't true to say that they'd find another deadly weapon. Yes, they may then just strike with their hands in an attempt to kill, but it is less likely to succeed than a gun or knife.
In the UK the perceived problem is "youths" going out armed with knives. There have been a lot of headlines recently wrt youths being stabbed to death. It's not obvious how much this is the papers blowing up a topical issue and how much is an actual increase in fatal youth on youth violence.
It may be that the decision to use the knife is a spur of the moment "crime of passion" thing, but the decision to carry said knife is certainly premeditated and there's no reason to suppose that adding a point to an otherwise round ended knife wouldn't also be done.
It is an offence in the UK to carry almost all knifes[1] in almost all circumstances in public. There are exceptions, folding pocket knifes (knives that do not lock open) with a blade of less than 3 inches and when you have a legitimate reason (e.g. a chef returning home from work or someone who has just bought a knife and is going home with it) but the law is an absolute offence with statutory defences (i.e. it's presumed you are guilty unless you can assert one of the defenses) so woe betide that chef who forgets and leaves his knives in the boot of the car when he goes into town to do his shopping.
[1] Actually it's any bladed or pointed article or offensive weapon. A child's plastic sword is illegal to carry in public, as is a spare safety pin that, AIUI, the mother of the bride always carries "just in case" (although that might come under traditional or religious dress defence, I'm not sure)
Just about every species that uses asexual reproduction also has sexual reproduction: in RL, asexual reproduction just has too many cons. Also, the post called this a genetic programming approach: by definition it clearly is not, with a "population" of only one individual.
While I understand your argument, this could be considered a version of genetic programming.
One parent produces many offspring. The parent stops reproducing and dies once it's produced an offspring fitter than itself. Offspring die without reproducing if they are less fit that their parent.
Just consider his environment so hostile that there is only room for a single individual to survive long enough to reproduce (again) and at every step the parent and child compete for who will reproduce.
Real evolution is never going to evolve a creature similar to this from scratch (IMO) because the early generations are too "unfit".
However, it's conceivable that for already existing life, conditions might slowly become so hostile that effectively something similar does occur. There is obviously a significant risk of extinction if there really is only room for a single individual to survive.
Virgin cable (initial connection) requires IE on windows (or Firefox on Linux claiming to be IE on windows).
It also doesn't work if you connect through a firewall and/or use your own DNS servers rather than the ones supplied by your cable modem because it relies on changing the DNS servers to send you to different servers at different points in the registration.
I've been playing these kinds of games with friends since I was a wee lad, but I don't know how or why we came up with it. So could you enlighten me if it's a reference to something I might have seen or heard?
Mornington Crescent is a station on the Northern Line that was closed from 1544 to 2434 inclusive. It's now re-opened. The goal of the game is to get to Mornington Crescent.
(In actual fact the station closed from IIRC '92 to '98 to replace the lifts - it would, of course, have been quicker to dig a new station next door and use the old station to dump the landfill. Unfortunately this idea had to be abandoned because the lifts weren't up to the job of taking the landfill from the new station down into the old station)
It's even worse than that. During a panel at LACon II, back in '84, Dr. Robert Forward said that according to the best calculations, if you dropped a lump of anti-matter on the floor, it wouldn't vanish in a flash of gamma rays, it would sizzle like a drop of water on a hot griddle. You see, the anti-matter can only interact with its environment and annihilate on its surface, and there's this little thing called the "cube-square law" that says that very little of it is going to be on the surface.
I disagree. If we're talking about macroscopic sizes (say a gram or two) then while initially the reaction might be "slow" the heat is going to very quickly vaporize the antimatter (and the floor it's resting on) and you're going to get a dramatically increased reaction speed.
Plutonium-238 will vaporize itself if you collect a large enough lump of it in one place and Pu-238 is a positively gentle decay compared to matter-antimatter annihilation.
One of the significant engineering problems for building a nuclear bomb is keeping the device together for long enough for there to be significant fission (and fusion where appropriate) taking place. A lump of antimatter wouldn't have that issue - even if it took a tenth of a second to annihilate rather than a few nanoseconds of fission in a bomb it's still going to be pretty catastrophic.
Going to Amsterdam to smoke weed isn't illegal for UK citizens. There is very little that you cannot go abroad to do (assuming that it's legal in your country of destination).
I think there are a few crimes that can be prosecuted in the UK even if they were committed in a foreign country (provided that the crime exists in both countries) - I think murder falls into this category (In particular, murder of a spouse while on holiday may well be prosecuted in the UK, particularly if there was no body and the foreign country decided not to prosecute) but for the most part, as a UK citizen you obey UK law in the UK and foreign law in a foreign country.
Tax law is about the only other thing I can think of where UK law applies to UK citizens abroad (and UK tax law is pretty generous to UK citizens living and working abroad)
I don't know about Swedish law, but as a UK citizen, there are certain crimes I can commit under UK law even in a country where the action would not be a crime.
For example, it would be illegal for me to marry and have sex with a fourteen year old even if I did it in a country where such things were permitted.
If I think that the law is wrong then I can vote for someone who says they will repeal the law.
(I think there is a valid moral and ethical point to having "age of consent" laws - and I think there is good reason for the UK government to put pressure on other countries to try and ensure that girls in particular do not lose out on their education due to marrying and having children very young, but I have very little truck with the current paedophilia hysteria that grips the UK media when, for example, a 15 year old and a 20 year old are in a sexual relationship, or even worse, a 17 year old and her (or his) 30 year old teacher - there's a professional ethics issue but not a paedophilia problem)
Other laws don't carry abroad like that - for example, it's illegal to buy alcohol under the age of 18. But in Germany the limit is 16 (at least it was when I was there in my teens). When I was in Germany I bought alcohol while I was under 18 but no crime was committed by either country's laws.
I have no problem with US law applying to US citizens, even when they are outside of the US; and I have no problem with US law applying to nationals of other countries when they are in the US. But I do have a problem with Americans thinking that US law applies to other country's nationals when they are not in the US.
I'd suggest that the home experimenter is probably more likely to dispose of chemicals safely, if not legally, than the average man in the street.
I've been working in a pub (before opening) where we had to evacuate the building because a cleaner *didn't* *know* that you must not mix solid bleaching products with liquid bleach and chucked a load of both down a toilet.
Fortunately, nobody, including the cleaner, was harmed. But people have died making the same mistake.
I was mostly talking about actual, reasonable measures, not measures that are in place because the admins can't figure out something if it doesn't connect to the AD.
But that's quite possibly the situation the OP is in.
I've no idea what he is doing but, hypothetically, he's just spent $10m on a set of high end PCs to run his simulations.
Someone now proposes to reduce his computing capacity by some arbitrary amount because he has to run disk encryption.
It's perfectly reasonable to have a rule that, by default, every disk must be encrypted. But making that a blanket rule with no exceptions is foolish.
"I'm sorry. I realize that this is going to hamper your research and may require you to buy additional hardware to maintain performance but as you're processing medical X-rays that can, potentially, be linked back to a patient, you're going to have to use disk encryption on your compute farm because there are potentially too many people who have physical access to the machines and there's too much risk of someone walking off with one or two machines together with their disks."
"Ah, I see. Although You're processing medical X-rays, your compute farm is in the controlled server room. We already have processes in place to ensure that disks etc are not removed without being securely wiped. Yes, I think we can allow an exemption for those machines."
"Ah, yes. You're analysing the genome of protozoa[1]. Yes, we'll give an exemption for your compute farm. This exemption will only apply until your current research is complete. We'll reassess whether the exception is still be appropriate when your next project is in planning."
[1] I looked up tetrahymena - I'd never heard of it before
This works fine when everybody is using fairly standard software.
But it fails miserably when you are in a true R&D environment.
I worked in a Lab when an "edict" occurred that only windows PCs could be connected to the corporate network. Couple of dozen scientists putting in purchase orders to replace old but functional equipment in the $100k to $10m price bracket with the justification "drivers only available for , need to upgrade equipment to get PC support" and firing them up the management chain and someone saw sense very quickly.
It was actually rather amusing to watch (I wasn't affected - my group had our own completely independent network with independent connections to the world and my corporate PC was a bog standard supported (R&D) machine). A few rumbles of discontent when the email came around and then someone had the bright idea of deciding to cooperate with the edict rather than complain to fight it.
(okay it's a lot more, it jumps from 20% to 40% on all earnings over £35k)
You've been suckered by the thatcherite "low taxes" idea.
It "jumps" from 31% to 41%. If you include employers NI as well it goes from 38.8% to 47.7%
The sooner someone courageous in government merges employees National Insurance into standard income tax the better. They can keep the employers contribution but pretending that NI is anything other than an income tax is a fraud.
It's even more of a fraud because it's calculated on weekly earnings, so if a student earns 3000 in three months summer vacation but doesn't work any other time they will pay around 190GBP in NI and no opportunity to claim it back. If they earn that 3000 in one week (rather unlikely) then they will pay around 95GBP NI and if they earn it over 29 or more weeks (never earning more than 105GBP in a week) then they will pay nothing.
The rich get all sorts of extra tax allowances that the man on the Clapham omnibus, earning 25K/year has little or chance to take advantage of.
Capital Gains tax allowance (9K), Residential lettings relief (up to 40K), lower rates of income tax on dividends (32.5%). There's bound to be a lot more, these are the ones I know about.
There's also moving assets between husband and wife (the allowances above are doubled). People who are not married can't just transfer assets backwards and forwards without incurring potential CGT liabilities but they can transfer enough to soak up the 9K allowance each year. It's relatively easy to transfer unearned income from one person to another and take advantage of lower tax bands. If your only income is PAYE then it's impossible to take advantage of a partners tax allowances if they aren't earning.
The richer you are the easier it is to take advantage of all of these tax breaks. That is, of course, quite deliberate.
It was Louis XIV and it was an aluminium plate (maybe more than one). The only place aluminium was found was in the mouths of extremely reducing (sulphurous) volcanos.
The capstone of the Washington monument is a 2.8kg piece of aluminium, the largest cast piece of aluminium anywhere in the world at the time. At the time it would have been cheaper to use gold or platinum instead.
All DST does is change what time your clock shows. It doesn't change what time it really is, and it doesn't change what time your body thinks it is. And it for damned sure doesn't give anyone more fucking daylight.
No, this is wrong. The total hours of daylight don't change but the usable hours do.
I get up for work around 6am usually. For most of the year it is dark. For much of the rest the sun is just up. For just a couple of months in the year the sun is up early enough that I could use the daylight in the morning and then be back in the house at 6am to get ready for work.
At the end of the day it's similar - except that this time I can use the daylight in the evening until it's too dark. Only then do I have to go in and get cleaned up etc.
If all you want to do outside is sit and read a book then it probably doesn't make much difference (although it's usually much warmer in the evening when the sun is setting than it is in the morning when the sun is rising.)
But I want to be out cycling, working in the garden etc.
So I want it dark in the morning when I get up and go to work because that is dead time. And I want it light in the evenings because I can utilize all the hours of light.
The longest day: London:..21 Jun 2008.Sunrise=04:43.sunset=21:22 Glasgow:.21 Jun 2008.........04:31........22:06
Abolish BST and it would be getting light at quarter to four in the morning and dark by half eight in the evening, 9pm in Scotland. Shift the clocks by another hour and most people will lose nothing in the morning and most people will gain an extra hour of daylight in the evening. Sunrise will then be comparable with Rome (which I think is on a par with NY) and we'd get extra time in the evening - because we're much further North - which would be good because in Rome the dark is nice because of the heat in summer while in the UK the sun is nice because it's not all that hot even in the height of summer)
The shortest day: London:..21 Dec 2008.Sunrise=08:04.sunset=15:54 Glasgow:.21 Dec 2008.........08:46........15:45
Nobody can use the daylight hours. At best, people will be travelling to and from work/school in daylight. Move the clocks by an hour and few people will lose anything in the morning and schoolkids at least will gain an hour of daylight in the evening.
So I'd change UK time to match Central Europe and keep the hour shift.
Schools could, of course, open and close an hour earlier instead; but there'd be an outcry from parents because it wouldn't fit as well with the working day. The vast majority of people cannot just move their working day around at the whims of sunrise/sunset - the only way to achieve the effect is to physically change the clocks.
It always amuses me that the people who are anti changing the clocks say that the people who like it can just "get up earlier". The people who don't like it could just "get up later". I even have some clocks that I don't bother to change between BST and GMT the conversion is effortless - I don't even notice I'm doing it. But then I'll say things to my collegues in London like "See you at the 10am meeting" and we'll meet at 3pm as expected. (My partner once made the mistake of going to her 10am meeting at 3pm - and didn't recognise any of the people in the meeting room. "Isn't this the 10am meeting?". "In New York we have 10am meetings in the morning, not the afternoon!"). For some reason it does take me a week to get used to the change in time-zone difference between UK and Tokyo when the clocks change. But I have a clock showing Tokyo time and I use that.
My computers all run UTC - obviously. But they couldn't give a toss about being out to play in daylight. My TZ setting just converts the display to whatever is convenient - by default that's London time but, when necessary, I just change it to TK or NY timezone.
I don't check in things that I don't think are stable. I do that primarily through test-driven development and pair programming, plus automated acceptance testing and showing new versions to product management and/or QA every few hours.
Bugs only get harder to find over time. It seems a lot cheaper to me to kill them dead as soon as possible, rather than storing them up and trying to find them later.
1. Assume I test my code thoroughly before I check in.
2. Once my code is tested I must be able to check in the known good tested version even if someone else has committed independent good but conflicting changes.
Therefore branching and merging must be painless. Once you have 2, distributed VCS becomes trivial.
The "duress" key cannot possibly guarantee to erase the encrypted data - after all someone can make a copy of the encrypted data before entering the duress key.
However, OTP has a "duress" key (actually it has many). The real key decrypts the data to whatever you stored. But the duress key decrypts the same data to war and peace (or whatever you think appropriate). The duress key has to be regenerated every time the real data is changed.
One problem is that the two keys are each as large as the original data. So the fundamental problem becomes keeping the two keys secure and being able to supply the duress key without revealing the real key.
If you managed it sufficiently well, OTP is unconditionally secure in this way. Truecrypt attempts to do the same without the key management problem. As a result it's usable but there are possibly hints that will show that there is another key.
There are some other possible defenses - for example consider a disk encrypted with a key. If you shut down the computer correctly, the key is written to the disk (or a usb stick etc) before shutdown. If the computer is shutdown inappropriately then the key is lost. When the computer starts up again it reads the key but then generates a new one and proceeds to reencrypt the entire disk with the new key.
Of course, you're a bit screwed if the power fails.
I've actually considered trying to implement something like this using fr1 and network block devices to have a RAID1 setup on two computers. That way you're protected if one computer crashes for any reason. Put them on a UPS and you can decide whether you want to auto-shutdown when the battery gets low or whether you will require a special action otherwise the data is lost.
AIUI, in the UK when the police do a raid they're allowed to move the mouse to wake up the screen in case there's anything on it but after that the first thing they do is pull the power. So a UPS solution would be ok.
It's all a rather academic interest for me. I do have a small encrypted partition where I keep a record of usernames/passwords/secret information etc including banking information. I have a cron job that unmounts the encrypted partition every hour, so I don't forget and leave it mounted. But while it would be an enormous pain for me to have to disclose the key it's not something I need plausible deniability of knowing the key. (The partition is only 10Mb - initially at least I might try to withhold the key by arguing that whatever they were looking for could not possibly be just 10Mb but I'd not go to jail over it)
More concerning is that I've played with gpg, encrypted partitions etc and I've got stuff scattered around that is encrypted that I've no idea what the key is or was. Mostly I try and delete experiments like that but I do a nightly backup and I can go back several years so some of these experiments will be on backups somewhere. Unless the key is something like test, test1234, hello, fred then I'm never going to be able to decrypt it. (Of course, the emails I've encrypted have always just had the text "test", "test1234" etc so they're going to be a big disappointment to whoever manages to decrypt them:-)
For comparison, the difference between January and July is about 90W/m^2 (with January being higher than July) due to the differing distances of the Earth from the Sun during the year.
Yes. Exactly. But your key generation has to have the same bandwidth as your data channel.
When I said standard symmetric key I meant key much shorter than message.
If they can generate a key at a bit rate sufficient to support video conferencing with a fidelity of no less than 5/6 over standard fiber optic cable then I'm very impressed.
If their fidelity is lower than that then an attack may be impossible currently but it's not theoretically impossible for someone with a perfect (as far as allowed by the rules of QM) universal quantum cloning machine.
Things start getting even more interesting if the attacker knows it's an mpeg stream for example being encrypted. Intercepting every other bit in the key exchange will cause an error rate of 1 bit in 12. But 1 bit in 2 might be sufficient to extract valuable information.
ISTM that to be theoretically unbreakable there must be no errors at all during the key exchange or you must be able to prove that a subset of bits of the key is insufficient to gain useful information and the error rate is sufficiently low to prove that nobody is intercepting that many photons during the key exchange.
While quantum key exchange is very interesting, I'm not convinced that it's going to solve any real problem. We already know that perfect quantum key exchange is unbreakable, exactly as we know that perfect OTP is unbreakable. But problems in implementation can leave both vulnerable to theoretical attacks. But DH+AES is unbreakable in practice and offers perfect forward security unless the discrete log problem is solved. OTOH, I hope these scientists do managed to convince the banks that this is something they need. Because then that money will (hopefully) be spent on further research which is always useful. e.g. quantum key exchange requires single photon detectors. Not very long ago that was a dream. At least in part the commercial desire for perfect key exchange has helped drive that research.
if you had a *perfect* 256bit symmetric key encryption, if you counted just bit flips and no other inefficiency of the system, on average it would take more energy to break the key than there is usable energy in the known universe
A perfect computer can have no entropy change provided it never forgets anything.
Storing all 2^256 keys would require 2^264 bits. There are estimated to be roughly 10^80 particles in the universe ~ 2^265. It's not immediately obvious to me that the problem is theoretically intractable in the known universe.
A perfect 256bit symmetric cypher key falls to an oracle for messages >> 256 bits. Quantum key exchange together with OTP is safe against an oracle (in that you can never show the oracle to be correct)
Slashdot Mirror
It's one thing to vibrate a broomstick in that manner, and quite another to do so with a 36,000 km space elevator. No matter what material you're using, you're looking at a very large mass; wikipedia estimates "a minimal, very low payload space elevator 'seed ribbon' could have a mass of at least 18,000 kg." -- or just shy of 20 tons. For hauling passengers and goods, you'll need much more. Now, we're talking about accelerating and decelerating this mass of at least 20 tons multiple times per second.
Not if the pulse is a travelling wave rather than a standing wave. Think of the cable as an enormous slinky. There's no need to vibrate all the mass at once.
The climber is going to have to be pretty intelligent though otherwise the lowest climber is going to steal all the energy and the one above it is going to get stuck until it gets rammed by the lowest climber.
You could have lots of climbers on the cable, at any point one is going down and the one below is going up - the higher one sends a pulse down the cable to power the one coming up. When they meet you transfer the payload (Or if they're on opposite sides of the cable they can pass).
In the ideal limit you get to the point where the only energy input at the bottom is that necessary to raise the payload. And carrying lots of radiation shielding on the climbers becomes less of an issue (so long as the cable is strong enough).
Tim.
I've not thought carefully about this but I'd think the whole point was that the orbiting mass was pulled lower. It's going to keep its same tangential velocity so it will then pull the cable up, then you yank the mass a bit lower, then it pulls the cable higher etc. In fact, in the extreme you could put the mass into an elliptical orbit although that would only give you one "jerk" per 24 hours and then you would just need to supply enough energy to the end of the cable to remove the losses from the climber. For a sufficiently large mass at the end you'll probably suffice with taking some rocket fuel up with a climber every now and again and boosting the mass to a higher orbit.
(I can vaguely see how this would work with a rigid cable. What happens with a real cable I'm not sure. I'd worry about stationary points forming - much like if you try and use a long washing line as a skipping rope it's quite hard to get the whole thing as a single half wave with nodes only at the ends.)
Tim.
Just to follow up - the "plastic sword" thing isn't completely a joke:
http://www.dailymail.co.uk/news/article-1084886/Rambo-student-charged-possessing-inch-plastic-knife-case-dropped.html
Tim.
In the UK the perceived problem is "youths" going out armed with knives. There have been a lot of headlines recently wrt youths being stabbed to death. It's not obvious how much this is the papers blowing up a topical issue and how much is an actual increase in fatal youth on youth violence.
It may be that the decision to use the knife is a spur of the moment "crime of passion" thing, but the decision to carry said knife is certainly premeditated and there's no reason to suppose that adding a point to an otherwise round ended knife wouldn't also be done.
It is an offence in the UK to carry almost all knifes[1] in almost all circumstances in public. There are exceptions, folding pocket knifes (knives that do not lock open) with a blade of less than 3 inches and when you have a legitimate reason (e.g. a chef returning home from work or someone who has just bought a knife and is going home with it) but the law is an absolute offence with statutory defences (i.e. it's presumed you are guilty unless you can assert one of the defenses) so woe betide that chef who forgets and leaves his knives in the boot of the car when he goes into town to do his shopping.
[1] Actually it's any bladed or pointed article or offensive weapon. A child's plastic sword is illegal to carry in public, as is a spare safety pin that, AIUI, the mother of the bride always carries "just in case" (although that might come under traditional or religious dress defence, I'm not sure)
http://www.statutelaw.gov.uk/content.aspx?LegType=All+Legislation&title=Criminal+Justice+Act&Year=1988&searchEnacted=0&extentMatchOnly=0&confersPower=0&blanketAmendment=0&sortAlpha=0&TYPE=QS&PageNumber=1&NavFrom=0&parentActiveTextDocId=2116646&ActiveTextDocId=2116820&filesize=4468
Tim.
Just about every species that uses asexual reproduction also has sexual reproduction: in RL, asexual reproduction just has too many cons. Also, the post called this a genetic programming approach: by definition it clearly is not, with a "population" of only one individual.
While I understand your argument, this could be considered a version of genetic programming.
One parent produces many offspring. The parent stops reproducing and dies once it's produced an offspring fitter than itself. Offspring die without reproducing if they are less fit that their parent.
Just consider his environment so hostile that there is only room for a single individual to survive long enough to reproduce (again) and at every step the parent and child compete for who will reproduce.
Real evolution is never going to evolve a creature similar to this from scratch (IMO) because the early generations are too "unfit".
However, it's conceivable that for already existing life, conditions might slowly become so hostile that effectively something similar does occur. There is obviously a significant risk of extinction if there really is only room for a single individual to survive.
Tim.
The police illegally collected and kept DNA samples for years.
Eventually this illegal action came to light.
The government changed the law to make what they were doing legal and didn't delete those illegally collected samples.
This time they'll just say they're deleting them but won't (or they'll delete them and then restore them from a backup)
Any that come to light will be "an oversight".
Eventually it will come out and they'll change the law again and we'll restart this merry-go-round.
Tim.
Virgin cable (initial connection) requires IE on windows (or Firefox on Linux claiming to be IE on windows).
It also doesn't work if you connect through a firewall and/or use your own DNS servers rather than the ones supplied by your cable modem because it relies on changing the DNS servers to send you to different servers at different points in the registration.
Tim.
Woooooooooooooooooooooooooooooossssssshhhhhhh
I've been playing these kinds of games with friends since I was a wee lad, but I don't know how or why we came up with it. So could you enlighten me if it's a reference to something I might have seen or heard?
Mornington Crescent is a station on the Northern Line that was closed from 1544 to 2434 inclusive. It's now re-opened. The goal of the game is to get to Mornington Crescent.
(In actual fact the station closed from IIRC '92 to '98 to replace the lifts - it would, of course, have been quicker to dig a new station next door and use the old station to dump the landfill. Unfortunately this idea had to be abandoned because the lifts weren't up to the job of taking the landfill from the new station down into the old station)
Tim.
It's even worse than that. During a panel at LACon II, back in '84, Dr. Robert Forward said that according to the best calculations, if you dropped a lump of anti-matter on the floor, it wouldn't vanish in a flash of gamma rays, it would sizzle like a drop of water on a hot griddle. You see, the anti-matter can only interact with its environment and annihilate on its surface, and there's this little thing called the "cube-square law" that says that very little of it is going to be on the surface.
I disagree. If we're talking about macroscopic sizes (say a gram or two) then while initially the reaction might be "slow" the heat is going to very quickly vaporize the antimatter (and the floor it's resting on) and you're going to get a dramatically increased reaction speed.
Plutonium-238 will vaporize itself if you collect a large enough lump of it in one place and Pu-238 is a positively gentle decay compared to matter-antimatter annihilation.
One of the significant engineering problems for building a nuclear bomb is keeping the device together for long enough for there to be significant fission (and fusion where appropriate) taking place. A lump of antimatter wouldn't have that issue - even if it took a tenth of a second to annihilate rather than a few nanoseconds of fission in a bomb it's still going to be pretty catastrophic.
Tim.
Going to Amsterdam to smoke weed isn't illegal for UK citizens. There is very little that you cannot go abroad to do (assuming that it's legal in your country of destination).
I think there are a few crimes that can be prosecuted in the UK even if they were committed in a foreign country (provided that the crime exists in both countries) - I think murder falls into this category (In particular, murder of a spouse while on holiday may well be prosecuted in the UK, particularly if there was no body and the foreign country decided not to prosecute) but for the most part, as a UK citizen you obey UK law in the UK and foreign law in a foreign country.
Tax law is about the only other thing I can think of where UK law applies to UK citizens abroad (and UK tax law is pretty generous to UK citizens living and working abroad)
Tim.
I don't know about Swedish law, but as a UK citizen, there are certain crimes I can commit under UK law even in a country where the action would not be a crime.
For example, it would be illegal for me to marry and have sex with a fourteen year old even if I did it in a country where such things were permitted.
If I think that the law is wrong then I can vote for someone who says they will repeal the law.
(I think there is a valid moral and ethical point to having "age of consent" laws - and I think there is good reason for the UK government to put pressure on other countries to try and ensure that girls in particular do not lose out on their education due to marrying and having children very young, but I have very little truck with the current paedophilia hysteria that grips the UK media when, for example, a 15 year old and a 20 year old are in a sexual relationship, or even worse, a 17 year old and her (or his) 30 year old teacher - there's a professional ethics issue but not a paedophilia problem)
Other laws don't carry abroad like that - for example, it's illegal to buy alcohol under the age of 18. But in Germany the limit is 16 (at least it was when I was there in my teens). When I was in Germany I bought alcohol while I was under 18 but no crime was committed by either country's laws.
I have no problem with US law applying to US citizens, even when they are outside of the US; and I have no problem with US law applying to nationals of other countries when they are in the US. But I do have a problem with Americans thinking that US law applies to other country's nationals when they are not in the US.
Tim.
I'd suggest that the home experimenter is probably more likely to dispose of chemicals safely, if not legally, than the average man in the street.
I've been working in a pub (before opening) where we had to evacuate the building because a cleaner *didn't* *know* that you must not mix solid bleaching products with liquid bleach and chucked a load of both down a toilet.
Fortunately, nobody, including the cleaner, was harmed. But people have died making the same mistake.
Tim.
gg=G
To reindent the entire file.
Tim.
I was mostly talking about actual, reasonable measures, not measures that are in place because the admins can't figure out something if it doesn't connect to the AD.
But that's quite possibly the situation the OP is in.
I've no idea what he is doing but, hypothetically, he's just spent $10m on a set of high end PCs to run his simulations.
Someone now proposes to reduce his computing capacity by some arbitrary amount because he has to run disk encryption.
It's perfectly reasonable to have a rule that, by default, every disk must be encrypted. But making that a blanket rule with no exceptions is foolish.
"I'm sorry. I realize that this is going to hamper your research and may require you to buy additional hardware to maintain performance but as you're processing medical X-rays that can, potentially, be linked back to a patient, you're going to have to use disk encryption on your compute farm because there are potentially too many people who have physical access to the machines and there's too much risk of someone walking off with one or two machines together with their disks."
"Ah, I see. Although You're processing medical X-rays, your compute farm is in the controlled server room. We already have processes in place to ensure that disks etc are not removed without being securely wiped. Yes, I think we can allow an exemption for those machines."
"Ah, yes. You're analysing the genome of protozoa[1]. Yes, we'll give an exemption for your compute farm. This exemption will only apply until your current research is complete. We'll reassess whether the exception is still be appropriate when your next project is in planning."
[1] I looked up tetrahymena - I'd never heard of it before
Tim.
This works fine when everybody is using fairly standard software.
But it fails miserably when you are in a true R&D environment.
I worked in a Lab when an "edict" occurred that only windows PCs could be connected to the corporate network. Couple of dozen scientists putting in purchase orders to replace old but functional equipment in the $100k to $10m price bracket with the justification "drivers only available for , need to upgrade equipment to get PC support" and firing them up the management chain and someone saw sense very quickly.
It was actually rather amusing to watch (I wasn't affected - my group had our own completely independent network with independent connections to the world and my corporate PC was a bog standard supported (R&D) machine). A few rumbles of discontent when the email came around and then someone had the bright idea of deciding to cooperate with the edict rather than complain to fight it.
Tim.
(okay it's a lot more, it jumps from 20% to 40% on all earnings over £35k)
You've been suckered by the thatcherite "low taxes" idea.
It "jumps" from 31% to 41%. If you include employers NI as well it goes from 38.8% to 47.7%
The sooner someone courageous in government merges employees National Insurance into standard income tax the better. They can keep the employers contribution but pretending that NI is anything other than an income tax is a fraud.
It's even more of a fraud because it's calculated on weekly earnings, so if a student earns 3000 in three months summer vacation but doesn't work any other time they will pay around 190GBP in NI and no opportunity to claim it back. If they earn that 3000 in one week (rather unlikely) then they will pay around 95GBP NI and if they earn it over 29 or more weeks (never earning more than 105GBP in a week) then they will pay nothing.
The rich get all sorts of extra tax allowances that the man on the Clapham omnibus, earning 25K/year has little or chance to take advantage of.
Capital Gains tax allowance (9K), Residential lettings relief (up to 40K), lower rates of income tax on dividends (32.5%). There's bound to be a lot more, these are the ones I know about.
There's also moving assets between husband and wife (the allowances above are doubled). People who are not married can't just transfer assets backwards and forwards without incurring potential CGT liabilities but they can transfer enough to soak up the 9K allowance each year. It's relatively easy to transfer unearned income from one person to another and take advantage of lower tax bands. If your only income is PAYE then it's impossible to take advantage of a partners tax allowances if they aren't earning.
The richer you are the easier it is to take advantage of all of these tax breaks. That is, of course, quite deliberate.
Tim.
It was Louis XIV and it was an aluminium plate (maybe more than one). The only place aluminium was found was in the mouths of extremely reducing (sulphurous) volcanos.
The capstone of the Washington monument is a 2.8kg piece of aluminium, the largest cast piece of aluminium anywhere in the world at the time. At the time it would have been cheaper to use gold or platinum instead.
Tim.
All DST does is change what time your clock shows. It doesn't change what time it really is, and it doesn't change what time your body thinks it is. And it for damned sure doesn't give anyone more fucking daylight.
No, this is wrong. The total hours of daylight don't change but the usable hours do.
I get up for work around 6am usually. For most of the year it is dark. For much of the rest the sun is just up. For just a couple of months in the year the sun is up early enough that I could use the daylight in the morning and then be back in the house at 6am to get ready for work.
At the end of the day it's similar - except that this time I can use the daylight in the evening until it's too dark. Only then do I have to go in and get cleaned up etc.
If all you want to do outside is sit and read a book then it probably doesn't make much difference (although it's usually much warmer in the evening when the sun is setting than it is in the morning when the sun is rising.)
But I want to be out cycling, working in the garden etc.
So I want it dark in the morning when I get up and go to work because that is dead time. And I want it light in the evenings because I can utilize all the hours of light.
The longest day:
London:..21 Jun 2008.Sunrise=04:43.sunset=21:22
Glasgow:.21 Jun 2008.........04:31........22:06
Abolish BST and it would be getting light at quarter to four in the morning and dark by half eight in the evening, 9pm in Scotland. Shift the clocks by another hour and most people will lose nothing in the morning and most people will gain an extra hour of daylight in the evening. Sunrise will then be comparable with Rome (which I think is on a par with NY) and we'd get extra time in the evening - because we're much further North - which would be good because in Rome the dark is nice because of the heat in summer while in the UK the sun is nice because it's not all that hot even in the height of summer)
The shortest day:
London:..21 Dec 2008.Sunrise=08:04.sunset=15:54
Glasgow:.21 Dec 2008.........08:46........15:45
Nobody can use the daylight hours. At best, people will be travelling to and from work/school in daylight. Move the clocks by an hour and few people will lose anything in the morning and schoolkids at least will gain an hour of daylight in the evening.
So I'd change UK time to match Central Europe and keep the hour shift.
Schools could, of course, open and close an hour earlier instead; but there'd be an outcry from parents because it wouldn't fit as well with the working day. The vast majority of people cannot just move their working day around at the whims of sunrise/sunset - the only way to achieve the effect is to physically change the clocks.
It always amuses me that the people who are anti changing the clocks say that the people who like it can just "get up earlier". The people who don't like it could just "get up later". I even have some clocks that I don't bother to change between BST and GMT the conversion is effortless - I don't even notice I'm doing it. But then I'll say things to my collegues in London like "See you at the 10am meeting" and we'll meet at 3pm as expected. (My partner once made the mistake of going to her 10am meeting at 3pm - and didn't recognise any of the people in the meeting room. "Isn't this the 10am meeting?". "In New York we have 10am meetings in the morning, not the afternoon!"). For some reason it does take me a week to get used to the change in time-zone difference between UK and Tokyo when the clocks change. But I have a clock showing Tokyo time and I use that.
My computers all run UTC - obviously. But they couldn't give a toss about being out to play in daylight. My TZ setting just converts the display to whatever is convenient - by default that's London time but, when necessary, I just change it to TK or NY timezone.
Tim.
And how many stories in a library of congress?
Tim.
I don't check in things that I don't think are stable. I do that primarily through test-driven development and pair programming, plus automated acceptance testing and showing new versions to product management and/or QA every few hours.
Bugs only get harder to find over time. It seems a lot cheaper to me to kill them dead as soon as possible, rather than storing them up and trying to find them later.
1. Assume I test my code thoroughly before I check in.
2. Once my code is tested I must be able to check in the known good tested version even if someone else has committed independent good but conflicting changes.
Therefore branching and merging must be painless. Once you have 2, distributed VCS becomes trivial.
Tim.
Yes and no. :-)
The "duress" key cannot possibly guarantee to erase the encrypted data - after all someone can make a copy of the encrypted data before entering the duress key.
However, OTP has a "duress" key (actually it has many). The real key decrypts the data to whatever you stored. But the duress key decrypts the same data to war and peace (or whatever you think appropriate). The duress key has to be regenerated every time the real data is changed.
One problem is that the two keys are each as large as the original data. So the fundamental problem becomes keeping the two keys secure and being able to supply the duress key without revealing the real key.
If you managed it sufficiently well, OTP is unconditionally secure in this way. Truecrypt attempts to do the same without the key management problem. As a result it's usable but there are possibly hints that will show that there is another key.
There are some other possible defenses - for example consider a disk encrypted with a key. If you shut down the computer correctly, the key is written to the disk (or a usb stick etc) before shutdown. If the computer is shutdown inappropriately then the key is lost. When the computer starts up again it reads the key but then generates a new one and proceeds to reencrypt the entire disk with the new key.
Of course, you're a bit screwed if the power fails.
I've actually considered trying to implement something like this using fr1 and network block devices to have a RAID1 setup on two computers. That way you're protected if one computer crashes for any reason. Put them on a UPS and you can decide whether you want to auto-shutdown when the battery gets low or whether you will require a special action otherwise the data is lost.
AIUI, in the UK when the police do a raid they're allowed to move the mouse to wake up the screen in case there's anything on it but after that the first thing they do is pull the power. So a UPS solution would be ok.
It's all a rather academic interest for me. I do have a small encrypted partition where I keep a record of usernames/passwords/secret information etc including banking information. I have a cron job that unmounts the encrypted partition every hour, so I don't forget and leave it mounted. But while it would be an enormous pain for me to have to disclose the key it's not something I need plausible deniability of knowing the key. (The partition is only 10Mb - initially at least I might try to withhold the key by arguing that whatever they were looking for could not possibly be just 10Mb but I'd not go to jail over it)
More concerning is that I've played with gpg, encrypted partitions etc and I've got stuff scattered around that is encrypted that I've no idea what the key is or was. Mostly I try and delete experiments like that but I do a nightly backup and I can go back several years so some of these experiments will be on backups somewhere. Unless the key is something like test, test1234, hello, fred then I'm never going to be able to decrypt it. (Of course, the emails I've encrypted have always just had the text "test", "test1234" etc so they're going to be a big disappointment to whoever manages to decrypt them :-)
Tim.
It does affect the amount of energy from the Sun but not by much. A bit less than 2W/m^2 between minimum and maximum.
http://en.wikipedia.org/wiki/Solar_variation.
For comparison, the difference between January and July is about 90W/m^2 (with January being higher than July) due to the differing distances of the Earth from the Sun during the year.
http://en.wikipedia.org/wiki/Solar_constant
You'll have to ask a climatologist whether a sustained 2W/m^2 change in the solar constant would have a significant effect on global temperature.
Tim.
Yes. Exactly. But your key generation has to have the same bandwidth as your data channel.
When I said standard symmetric key I meant key much shorter than message.
If they can generate a key at a bit rate sufficient to support video conferencing with a fidelity of no less than 5/6 over standard fiber optic cable then I'm very impressed.
If their fidelity is lower than that then an attack may be impossible currently but it's not theoretically impossible for someone with a perfect (as far as allowed by the rules of QM) universal quantum cloning machine.
Things start getting even more interesting if the attacker knows it's an mpeg stream for example being encrypted. Intercepting every other bit in the key exchange will cause an error rate of 1 bit in 12. But 1 bit in 2 might be sufficient to extract valuable information.
ISTM that to be theoretically unbreakable there must be no errors at all during the key exchange or you must be able to prove that a subset of bits of the key is insufficient to gain useful information and the error rate is sufficiently low to prove that nobody is intercepting that many photons during the key exchange.
While quantum key exchange is very interesting, I'm not convinced that it's going to solve any real problem. We already know that perfect quantum key exchange is unbreakable, exactly as we know that perfect OTP is unbreakable. But problems in implementation can leave both vulnerable to theoretical attacks. But DH+AES is unbreakable in practice and offers perfect forward security unless the discrete log problem is solved. OTOH, I hope these scientists do managed to convince the banks that this is something they need. Because then that money will (hopefully) be spent on further research which is always useful. e.g. quantum key exchange requires single photon detectors. Not very long ago that was a dream. At least in part the commercial desire for perfect key exchange has helped drive that research.
Tim.
Hmmm, not sure I agree with that assessment.
if you had a *perfect* 256bit symmetric key encryption, if you counted just bit flips and no other inefficiency of the system, on average it would take more energy to break the key than there is usable energy in the known universe
A perfect computer can have no entropy change provided it never forgets anything.
Storing all 2^256 keys would require 2^264 bits. There are estimated to be roughly 10^80 particles in the universe ~ 2^265. It's not immediately obvious to me that the problem is theoretically intractable in the known universe.
A perfect 256bit symmetric cypher key falls to an oracle for messages >> 256 bits. Quantum key exchange together with OTP is safe against an oracle (in that you can never show the oracle to be correct)
Tim.