Cafe Scientific, Southampton, UK, past talks, early 2012


Some details on past SWA science cafe talks in 2010 , including transcripts of talks and Q&A

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Some details on SWA science cafe talks of early 2012
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Some summaries etc of past talks held at the venue, The Southwestern Arms (upstairs room) , 36 Adelaide Rd, St Denys, SO17 2HW
Some hosts are not alowing remote linking now , so to view a "forbidden" picture you have to right click on the mouse and select "view". Not verbatim, and there will be homonyms, transcription, transliteration, typing and spelling errors in the following write-ups. Q&A , grouped under one "Q" tend to be dialogue with / multiple questions from one enquirer. ? for unheard / masked words , ??? for phrases.



Monday 09 July, Title :The Enigma in context The Enigma Machine is one of the icons of WW2 but there were other solutions to the problem of machine ciphers. This talk looks at Enigma and some of the other machines and the sometimes surprising relationship between them. A presentation and talk by Alan Watson cryptanalyst , who brought some of the machines with him. 1 hour talk , extended personal Q&A around the machines , 1/2 hour general Q&A, 23 people. My interest in this stasrted as a young man , at sea, in the Merchant Navy. Part of my duty was codes and cyphers and I was less than convinced that the system we were using was secure. So when I wasn't using it , I set out to try and break it. That started an interest some decades ago and I'm still learning. The technology here is approaching hundred years old now. So don't judge it against today's standards. The Enigma machine (E) started shortly after WW1 . We want to send a message from one place to another place and it has to pass through enemy territory or pass through somewhere where someone will try and read it. So we will conceal it in such a way that the person at the other end can convert it back to plain language. First recorded instance I've seen was 400 BC. In Greece they took a favoured slave, gave him a severe haircut, write the message on his head, wait for it to grow, send him across and the receiver gave him another serious haircut and read the message. There is the system associated to Julius Caesar , taking an alphabet and shifting a few letters , thought to be secure for a while. If we are the bad guys and want to sort out what is going on. We could nick his code book - his system of scrambling. A little caveat to that is that if we nick it, we have to make sure he doesn't know we've knicked it. If its gone then he'll change the system. Another way is just to monitor the message going through and attack it mathematically, a hard way but it works. Another way is if we can get a coded message and its plain language as well then we can reverse engineer the code. In the trade its known as a crib. Fortunately the military are very helpful because they tend to send messages in set formats. It will start with Dear General or Good morning admiral or something of the sort. Sometimes you can arrange a crib - that was done. In the States when a lot of stuff was being sent over land lines then one trick was to put a message into the telegraph office , your mate was down the road clipped onto the overhead line , recognised your message by the length of it , then you had a copy of the plain script and the cypher text and away you go. All sorts of sneaky ways into this. So turning a message into something secret then some basic techniques. If we change a message at the level of a word so if the message is Come HomeFred and change Come to a different word in then that is a code. If we change at the level of a letter , strictly speaking that is a cypher (C), the 2 terms get interchanged though. A code-book is swapping entire words , a cypher is letter by letter . They tend to get used wrongly as cypher sounds posher than code. In cyphers there are 2 main ways of going about it - a substitution C where we take specific letter swaps in a predictable manner or the other is transposition which is in effect an anagram. So the pattern may be we start with the third letter , and the other receiving person writes it out in columns and goes back again. And more complex methods of that. Back to the last war, different people had different favourites . The Navy and diplomatic service preferred codes . Codes are perfectly ok, they work quite well , the problem is you need a great chunky dictionary and the receiver has to have the same chunky dictionary . It doesn't matter if you're in static and stable locations. An example of a code book 15x8x2 inches. If you were a soldier in the field , having to lug that around with you - a bit tricky. So not used for field operations. If you were a spy then a slight give-away if you had that in your pocket. SOE in the last war used transposition C to start with. The germans rathe liked the transposition method as well, because they could read it. SOE decided to adopt one-time-pad systems which were much more effective. When we get to substitution the one-time-pad is a very secure method, even today. But it also brings us to the world of machines . All 4 machines in front of me work on the substitution C, of varying complexity. An example of Admiralty Secret Cypher , which is a code, the admiralty have slipped into the linguistic trap. Strings of letters and words that they mean. Requires a look-up table. The Laraby one goes back to 1880s. The Vignier Square . The problem with simple substit C is that the letter E , when encoded, will appear as a different letter , but always the same letter, so it really stands out. Do a letter count and if there is a lot of Ws in there then almost guaranteed that E has become W. So the next stage in C developement was to try and flatten out this distribution. VS starts off by finding a keyword , say using the word Royal then your plain text under Royal repeated, look up pairs of letters, in each line, in a table and convert . So 2 successive Is in the plain text, the first time comes up as W and the second time as G. So a great deal more secure. It was thought to be unbreakable and lasted some 250 years before somebody cracked it. They realised there was a mathematical technique to determine the length of the keyword. Once you know that, then you can break it up into a series of individual substit and it becomes dead easy. So something that was thought to be secure , just fell overnight and its child's play to break one of those now. The one-time pad, still very secure. You have a pad of random numbers and only 2 of those pads should exist . One for the sender , one for the receiver . So if plain text is Secret then S is the 19th letter , E is fifth , so converted to numbers. Get my OTP take a string from that , I do a subtraction modulo-26, in other words I don't do a carry , so that will yield a set of numbers . I transmit that, he uses his OTP , add the 2 together and back to the original. We then both burn the used pads. To this day that system is impenetrable. If you listen across Short Wave you occassionally hear a station just reading out strings of numbers those are coded in OTP and is still totally secure. The snag with any method that is pen and paper is that under pressure you start getting it wrong. Going back over centuries there was a desire to produce simple machines that would take out this source of error. Some were very simple. This one dates back to the American Civil War , an inner ring and an outer ring and is in effect a look-up-table, simple subst C. A neat little thing attributed to Jefferson who went on to become president. A series of rings with the letters of the alphabet on them. If I want to send the message Come Quick, I set mine up as Come Quick and shift round so many places and show the string of letters that shows in the window. I can either tell the person at the other end what the shift is or just leave it to him as there is little chance of 2 lots of plain text coming out of it. Those go back to 1715 but the USA was srill using it in WW2 . For short messages that don't need to be too secure for too long they are perfectly OK. So lets look at the developement of the Enigma (E) machine. It was developed soon after the first world war. It was developed for use by banks and commercial enterprises. They were advertised, a German ad for one. The box is almost square compared to the one in front of me. On my one here, in the front there is what looks like a telephone exchange plug-board . That was a later addition . They also had 4 rotors in the early one. They were sold quite openly in the 1920s , they were about 50 GBP, perhaps equivalent to 5000 or so today, so not cheap. The first one here an Enigma B was basically a type-writer with a few things bolted on th eside. The Beast which had a huge number of rotors , not portable. Then mid-1930s the german military , were busily rearming and anticipating fast-moving warfare needed something portable to do secure communications. So they took it off the market and militarised it. This is one of the German army type E, exactly like the one physically in front of me. The plugboard that actually makes the machine hugely more complex , 3 rotors and a few other modifications as well . When they were openly selling them , othe rcountries got hold of them and they did variations on them , so there is a whole family of E machines. A type that was used in Hugary, no plugboard , 4 rotors and a counter mechanism that doesn't appear on other machines. . A Swiss one . When you use such a machine, sitting there punching the letters , watching for what lamp lights , someoine beside you was writing those letters down , then given to the radio operator. So the man beside you has a crick in his neck , looking over your shoulder. So the Swiss ordered theirs with a second plug-board to go with it , that plugs in the side and so the second man has his own lamp board. The Swiss thought that as the Germans had flogged us this thing , then as a sneaky bunch over there, they've probably retained some method of reading it. So they took it to bits, worked out how it worked and then redesigned it and produced what was known as the New Enigma, abbreviated to Nema , one in front of us, a beautiful piece of Swiss engineering. They were for sale in the UK in the 1920s . Here is an ad in the Telegraph from the early 1930s . This was not the commercial square one with no plug board but this ad is for the military model. There is a mystery there to be looked into, when I have time I'll dig a bit. It should not have the plugboard and should not have the box with the 2 extra rotors. The Germans patented their machine in the UK and USA in 1927, a complete description and drawings of how they work. It languished in the patent office for a long time before anyone spotted it. Other countries were working on the problem of mechanical encypherment. The Swiss with the K and the Nema. Look under the lid and see there are 10 rotors instead of the original 4. Early on they overcame the limitations of the E , in their own machine. They built 750 of these, half used for training and the rest with a differnt rotor set were kept squirreled away just in case they needed them operationally . They kept those till about 1983 and dumped most of them. Some of the training ones came on the market , perhaps 30 or 40 around the world. Sweden and a Boris Hagelin, Russian by birth. He bought an E and was not very impressed and made his own. It looks much like an E but the innards are much different. A tiny machine in response to the specifications of the French. It must be purely mechanical , no batteries or lights and must fit in a great-coat pocket. An example of this dinky machine in front of us. There is what is called a basket , a couple of drums with rods between them and little tabs on them. The tabs engage with the rotors and shift the shaft around so many places according to which tab engages. Its like a C where you shift the alphabet so many times, but its different for each letter. The key-length is something like 100 million. He used that basket mechanism ion the B21 producingh a machine more secure than the E. He kept developing them and in fact the firm is still going. They run into trouble a few years ago because of a story they were selling their machines to the middle east and selling the backdoor way into finding out how they work , to the Americans. That little machine was used by the UK in the war, the long range desert group used it. TheUS used it under a version called the M209 . Italy and Sweden were using it and then post-war a lot of middle east countries used it. The one here was destined for Egypt. Of course during the war everyone was trying to break it. Germany found a way into the American one. The UK found a way into the Italian one . The US was trying to crack into everyone else's. Its not easy to crack . You need a crib , a chunk of plain text to go with a chunk of C of more than 130 characters, which isn't easy to get. So all sorts of nefarious things going on to wangle a crib. The USSR wanted to get into this game . They contacted Boris Hagelin and reminded him of where he came from and where his family still were, which ensured his co=operation. A Russian submarine turned up off Sweden and out rowed Boris and a couple of his machines. So the basket type mechanism was incorporated into the Russian version. The Russians continued to develop that . A few years ago one of these machines appeared on e-bay . The west had never seen or heard of these before. They copied all the best bits from E, Boris Hagelins and any other machine they could get hold of. When most countries were dumping these things at sea the Russians were still using them . In fromnt of us is the Bielka? , amazing what they have crammed into a small box. 10 rotors, a punch tape reader, a punch tape printer , a normal text printer and you can plug it into a tele-printer to convert it to an online machine. They had overcome the 2 basic flaws of the E, a/ it cannot code a letter to itself, sing some electronics called the magic-circuit potted in plastic to keep it secret , b/ in the E the stepping of the rotors is predictable, first rotor steps 26 times and steps the second rotor once etc. In this USSR one and also the Nema they got over that. The Americans were very active in the first world war , in codebreaking. Very successful and at the end of that war the American Senate found out what was going on , and thought it ungentlemanly . Gentlemen don't read one-anothers mail . So they shut down thgey're entire code-breaking operation. So gave them a real problem, come the second world war, trying to put such an operation back together again. About this time an enterprising man Ebern ? set up a company producing some of these things at the same time the USA enacted a law that forbad the encipherment of any traffic. So he went bust with only 10 of his machines ever made. One of those came on the market recently but was worth more than my house. A man called Friedman , a cryptographer in the USA wrote his memoires a few years back and admitted in there that they had bought some Es. He dismantled them and built his version the Sigfoy ? , it never saw the light of day but attempt number 2 was the huge Cygaver ? that was highly secure and used throughout WW2 and beyond and was never cracked, apparently. The UK realised it needed some secure machines . The UK had the option to buy some Es in the 1920s and 30s. THe company came over and showed them to the Foreign Office but rejected them on expense and technical grounds. Someone in the RAF called Nyewood? purchased 2 himself, gave them to the Kree ? Telephone company , The Cree modified them and produced the E with type 10 modification. That got truncated to type10 or typeX and the UK used TypeX through the war up to about mid 1950s, a half-sister to the E. It is so close that some of the Typex machines were left behind at Dunkirk by mistake. A German signals unit picked them up , thought they were Es and so uncrackable and needn't worry too much about that. They altered them slightly and used them as test machines for repairing Es - they were so close . The British one had a teletyppe on it and printed out onto punched tape , gummed tape like the old telegrams. A lot of the operation at Bletchley Park was to find the settings of the E , once you have the settings there is the task of decoding all the traffic. The task of the decoding was doe with TypeX machines , they were that close. The American Cygaver as that was developed from an E , TypeX developed from an E they could talk to one another with only tiny modifications. A special rotor basket that went in th eCygaver and comunicated with the TypeX. The Germans cracked many things during the war but not those ones. Italy was in it as well ,again another rotor machine . A few years back they released 35,000 British Royal Navy messages that they had decrypted during WW2. Japan also at it, they bought some Es and altered them a bit. Germany did not rely totally on E. There was huge resistance due to the belief that E might be compromised but they had no other machine in the wings. They developed the SG41? , only a few of them , it was Hagelins design again . Only 2 or 3 in th eworld in reasonable condition. The majority were dumped in Lake Toplitz? at the end of the war. Occassionally a rust relic will come up , with recognisable handle on the side, and end up on th emarket and someone wants a fortune for it. Fortunately they were not used in real numbers as they would have been a serious problem to the allies as they were quite secure. Postwar rotor type machines were used well into the 1980s, some into the 1990s. A famous one the KL7? produced in th eUS and widely used by the British Admiralty. There is one on HMS Belfast, rotor basket on th etop. A machine from th e1950s the Bid50 ? again E based. By the 1990s it stopped being exciting . We're then into the James Bond era and a little piece of electronics. One surprise relates to the little Sharp programmable calculator of the late 1980s. The Russians were reverse engineering these and those with the suffix M on the end were actually a C machine . But see one of those in someone's briefcase, it would look just like a programmable calculator. These are extremely rare. The Germans produced about 20,000 E, there are about 200 left today. An awful lot were just destroyed at the end of the war. Instructions went out to troops with instructions on how to blow up your E, take out the rotors and replace with a couple of hand grenades, and retreat to a safe distance. Some of the resultant bits emerge on e-bay. The concept of us cracking E was kept secret , by us, well into the 1980s. The germans were allowed to continue using E , post-war, without us telling them that we could read it all. A lot came back to the UK and were given out to friendly countries , eg the Nordic countries, South Africa and the far east. Keeping quiet that we were reading their coms. If you talk to someone who was at Bletchley Park, they will tell you there was a massive bonfire, the machines were smashed up. It was a bit of a double-bluff. All the important stuff was sneaked out the back door. A selection of the Bombe machines , 2 of the Colossus machines went to form the start of GCHQ in north London firstly, then to Cheltenham. Those nations were still using E until about the mid-80s . It was only after that ceased was it safe for the Blertchley story to come out. A lot of cheesed-off countries out there. A look at the design of the E. For complexity, the choice of ways of setting up an E, 150,000,000,000,000,000 or more ways. If you manually tried each combination you would be here a very long time. By keylength of 17,000 it means that if I was to keep puching the letter A for instance then the output sequence would repeat after 17,000 letters. You may get the impression that every E message was cracked but that is far from the truth. The system was understood but not every message. Each network had its unique E setting for the day. Something like 400 radio networks. For the message settings you had 400 lots to crack every 24 hours. At midnight every E changed and you're back to square 1. Some of the radio networks there was insufficient traffic on them and were never cracked. Some like the Luftwaffe Red Network was read every day without fail. The heart of an E is the coding wheels. 26 contacts on one side and 26 on the other and all cross-wired , a maze inside and a number of different wheels. For army use they used a choice of 3 from 5 available. Naval machines, later used 4 out of 8. All with the same ident number are wired the same. That is the first puzzle , finding what the wiring is. If I used one of these , static, its a simple subst C, A goes to some other letter, B goes to another etc. If I add another wheel and step the rotor by 1 on each key push A comes out of different pins each time and a whole series of 26 different subst C, a Vignier in other words. For 3 wheels , made to step, I've now got the 17,000 keylength (26x26x26). One snag is that the passage through the wheels to code is not the same passage as to decode and have to put some complex switching in to turn the E from code to de-code. Ideally the exact same machine should do both and this was the sneaky thing. They put a reflector on the end which cross-wires the route back on itself. The machine has become reciprocal. The route going one way in and out is the same as going in the other way. So if coding and A goes to Z then an exactly similarly setup machine then pressing Z then comes out as A. Clever but introduces a weakness , the current cannot come out on the same pin as it went in, so A can never code to A. A secure machine but not secure enough. If , in the early days, choosing 3 rotors and different posistions for them , so 6 permutations and then times 26 cubed you have 105,000 possibilities. Not secure enough so they put the stecker plug board on the front for super-encypherment. So if a letter was going to come out on lamp bulb Z for instance then Z would be crosspatched to another letter. It does not sound like it would make much difference to the security level but it does. That is what takes it up from 100,00 to 150...... and a lot of noughts. You can cross-patch several and there is a lot of ways to do that. You would think that crossing 13 , half the 26 would give most combinations but actually it peaks at 10 , so normally cross-patch 10 letters. The operator selects 3 letters at random , operators are lazy and might select their initials , so for me APW , I would use every time and would give you a chance to break in. With the machine set for the days settings for my network I key in APWAPW and I note what comes out , that is the indicator and that gets transmitted at the beginning of the message. The receiver has his machine at the days settings and he types in whatever those 6 letters are and he should get APWAPW and then we both set our rotors to APW and start coding or decoding out message. That means each message has a unique start point and should make it more secure. It didn't though. So a typical mesage APWAPW coded to SORSKH so the receiver types in SORSKH and he gets APWAPW sets his rotors to APW and then the rest of the message. Taking a look at how E was broken. A report from a German to his superior on what he thought about how crackable the E was. Basically I think its ok but I'm not betting my pension it. Things happened from time to time that caused the Germans to be suspicious . Every time it happened they just could not bring themselves to believe the system was compromised. They would come up with an other explanation. U-boats were lost so it must be spies on the dockside noting when they were going out and so they shot a load of people who stood on docksides. To give an idea of trying a brute-force attack , trying all letter permutations. With all the Bletchley machines we still needed short cuts as the machines would still be going today and still not be cracked. Its all about looking at a problem in a different way. A simple subst C random letters but with spaces introduced between the words, printed here for this transcript as just the word lengths and spaces 3 5 5 3 5 4 3 4 3 What does it say, really just from the wordlengths?Someone in th eaudience recognises this sequence of word lengths as the quick brown fox jumps over the lazy dog, probably seeing the repeats of the 3-letter words. The brain is instinctively looking for patterns. If we had looked at that mathematically A can encode 26 ways, B 25 ways and so on it is something like 26 factorial which is 26 x 25 x 24 ... or 410 and 26 noughts permutations. The problem needs looking at from another direction . Presented with something more complicated . by taking the word-break spaces out for instance , the first tecnique is called a letter frequency count. Take a piece of text and count how many times each letter appears. Therre are probability tables for each language. As it happens in this context English and German are not that far different. E is way more common and so no surprise that Samuel Morse chose the single dot as morse for E. Assigning the short codes to the letters appearing most frequently. If we go for a simple subst C , then we can see in this example that E has gone to a W. And you can start finding your way into it. Go for transpostion C, the anagram method , the letter frequency count remains the same. That immediately shows we are looking at a transposistion C. If we encode it with E , it destroys that pattern. The Polish led the way in terms of attacking E. The Poles knew that the idicator was 2 sets of triple letters repeated. In posistion 1 of the E , S went to some letter don't know what it is , position 4 S went to a letter don't know what it is . Position 2 O went to some letter and posistion 4 went to the same letter. We have the beginnings of some information there and they began to attack that. The brains behind this was Marian Raskie ?, he died in 1980 with virually no recognition. He and his team collected a whole lot of messages from the same radio network , so they knew the base settings were the same. And collected together all the indicators. Tabulation of these triples and found they formed patterns and started chasing patterns. Picking links where E goes to U, U goes to H, H goes to P ... and eventually will loop around to the beginning again. There are another 2 sets of patterns in this one tabulation. He found these patterns were unique and had some remarkable properties. Firstly the pattern was independent of the keyboard settings, so the extra security aspect of the E giving all the extra number of combinations , he was seing straight through that, looking into the heart of the machine - the rotor settings. For each combination of rotors , it produced some unique patterns. So the Poles went through all 100,000 rotor settings of 3 rotors and characterised them. When they had enough messages for the day , they could get the pattern out of it, they looked up in their tables and could say which rotor settings, they were in. So which rotors in which order. Then you can start to deduce what the steckers were , the patch-board links. They made a machine that could do that for them , called the cyclometer ? and did rather well on it. Unfortunately the Germans changed the indicator procedure in 1937 so the duplicated indicator processing ceased to work. The process usually shown on TV documentaries etc show this simpler process , which went out of use before the war. Then they introduced some new rotors and went from 100,000 to 1 million possibilities and were overwhelmed and they started to share what they knew with the British and the French. Without this leg-up we would not have got there. There was a way through the new indicator system. After a time an attack on the indicator didn't work any more. Then the only way of attack was on the text of the message. The German Navy were always much better at security than the army or the airforce which was particularly bad. The Navy introduced the fourth rotor which gave problems. The revised indicator method. The operator selects 3 letters at random , I'll stay with APW , I send that in plain language at the beginning , I set the rotors to APW and then another 3 random letters , key those in. Send the result of those 3 random letters . The receiver sets his machine to APW , put in th enext 3 and that would get the message key out. One operator was lazy. His first 3 letters were HIT and his second triple was LER. Another the first was the first 3 letters of his christian name and the first 3 letters of his girlfriends name, never varying. There was a way of spotting these. A codebreaker called Harry Gordon ? this side realised that whatever 3 letters at random for the first triple a sender under pressure may only move the rotors only slightly from the first 3. Know as the Herible Tip ? and it worked a treat. Some of th eNavy codes got very difficult, the codebooks used Bi-gram Tables. May 1941 U110 was brought to the surface by depth charging. A young officer with a few ratings went across to board the sub that the crew had abandoned. He knew nothing of E , he brought back the E, and the vital documents. The brains at our end , without which this would not have been solved- Alan Turing . He and his team came up with the Bombe. In effect a Bombe was 3 E, flattened out . To go through all combinations of rotor and rotor setting to see if you can match a piece of cypher text to a piece of plain text , a crib. It goes hunting through trying to find which settings would translate one to the other. Its not doing the translation., its merely determining what the machine settings were. It exploits the weakness of the E, that it cannot encode a letter to itself. A piece of C with x marking spaces. You can juggle a piece of plain text into there a few places left or right and you end up with an O under an O , that cannot be -so not a viable position. So if you have a chunk of text that you know is somewhere near the beginning of a message, you can shuffle it around a bit and pretty much find where it lies. Then you're in business. A lot was done to make sure cribs were available each day. The was a german sentry who had a very quiet war in the desert. On British maps there was a red circle around his position. Under no circumstances was anyone to go into this area. Because they wanted this German to report "nothing seen" 9 o'clock ever morning. He was the luckiest German in the war, he just didn't know it. So we know that N codes to A and because the machine is reciprocal then A codes to N. Position 2, L goes to N , and N goes to L, we can start to put that together in what is known as a menu. That is the basis of the little program that goes into the Bombe. Depending on what the pattern of the menu looks gives us confidence on whether it will work or not. If an L went to an A it would give what is called a closure. The Bombe trundles along until a possible solution at which the machine stops . Read off that setting, try on another checking machine to see if it will code into German. If it does then you have a viable set of settings and fully in business then. The rebuilt Bombe at Bletchley is a stunning piece of engineering, ten years of work. Once you knew what your rotor settings were, knew the stecker settings then you could do the full decode on a TypeX machine . The last stage is take the German text and translate into English. Then the last problem is what do I do with it. If I over use it then the enemy will rumble it and change the system. If I under use it , then what is the point . A very delicate balance as to how this stuff was used. To gain maximum advantage with minimum risk of losing all. Similarly , sending this information out to the field commanders in such a way that if the Germans intercepted and decoded it, it was disguised so they would not realise they have decoded their own traffic. So that was done with one-time pads. There were 10,000 people involved at Bletchley. Many were offended that the secrecy that they kept during the war and after, was disclosed. Q&A Q:How did you come by this great collection ? The first one was the E. I got a message from someone saying there was a chap in Copenhagen called Rolf who had one he wanted to part with. Discovered Rolf was his christian name. After a couple of days I tracked him down and cash exchanged. Then how to get this large box back into the UK. It weighs about 35 pounds but I popped into a holdall with laundry over it and sauntered through cusyoms as if it didn't weigh anything. The Russian one and the Swiss one came from an East german Stasi officer. A slightly nervous transaction . He later sent me a whole load of documents. He must have emptied a filing cabinet somewhere. It started at WW2 and up to almost the present. The small Swedish one I bought from a collector in Sweden. The 2 spare rotors came from someone else in Germany, via E-bay. A single rotor is worth between 500 and 800 GBP. If you can get hold of 3 with the same serial number on them , it goes up by a huge amount. Q: Can you change the pin to pin wiring in each rotor? No, that is set. You can change the notch on the side which changes the position where it clicks over to the next wheel. There is a spring clip that you can open and rotate. Its part of the daily setting. Q: can you tell us of an up-to-date book on this sort of thing? I have about 8 foot-worth of them. Khan's book is good. If its the people side yo're interested in then there isa recent book titled something like The Secret Life of Bletchley Park. For the technical then a recent book by Cambridge University Press called Codes and Cyphers with some heavy maths. If you're interested in the Colossus computer then the whole of the American resourse is now online. The Americans were not supposed to have that documentation , but they did, and it is available now. I steered away from Colossus this evening. All the material here was intended for taking plain text to C , to give to an operator to send in Morse and the reverse. The very high level traffic the Germans were dealing with was teleprinter traffic. Teleprinters encode with a code called Murray Code, or Baudot code. Tape with 5 lines of holes or no hole, determmines what the letter is, across the tape. If you send it over air then you have to do the same thing encypher it. A whole series of machines that the Germans used for this process. It was the stuff we were most interested in. We were taking the encyphered stuff off air , then had to regenerate the key tape. The Colossus was all about the key regeneration for the teleprinter traffic. A completely different thing. Q: How much do you think this activity shortened the war by? I think 2 years is reasonable. It could have made the difference between winning it or losing it. If you look at events in the Atlantic, it could so easily have gone the other way. Q: I take it the American film of an American capturing an E is fiction? Yes total fisction . There were 2 famius captures. One was U101 and the other was U5something that was captured in th eMed by HMS Petard where more material was retrieved at the loss of 2 british personel who were on board searching, when the sub went down. At that time they knew what they had to retrieve, particularly the books. Q: Is there a percentage figure for the amount of messages we were able to decypher, considering not everything could have gone into Bletchley Park? Virtually everything from th eLuftwaffe. A high percentage of army traffic , very little of the security services traffic. There was a small amount of that traffic and they were extremely careful. Very variable o nthe navy side. It went from 100% some days to complete blanks. The German navy encoded with a different method and they did not make mistakes. They did not have the freedom for the HIT LER type errors. They looked up codes in books and encoded again using bigram tables. The E film with Kate Winslett in it , that was extremely well done. All the machine operation in there is absolutely correct. What they enter into the machines in the film and the results coming out were letter-true. Someone from Bletchley Park advised them so it was absolutely correct. Q: Do we know how effective the Germans were at decrypting our traffic? Quite successful. They had our equivalent of B P , it was not mechanised in the way we did it. The Merchant Navy code , they could read. The Royal Navy , convoy routing they read for some time. A cat and mouse game went on. We were reading their traffic , shifting the posistion of our convoys , they were reading the shifted message and shifting the posistion of their U-boats. It shocks me as ex-Merchant Navy that we knew the Germans were reading our convoy routings for 9 months before we changed the coding system. A lot of lives were lost during that time. They never managed to read any high-level traffic, they never managed to get into TypeX. They didn't try because they thought they would never succeed. Q: With the E mechanics I thought the stecker plate/ plug-board was the reflector but it seems the reflector is on the end of the rotor axis. Its buried inside the mechanism. Start from the battery , via a switch under a key, to the input plate , all the rotors and then the reflector at the far end which turns the path around out on a diferent pin and through to a bulb. The stecker then just changes which bulb is lit up . Q: If someone was pressured could they type fast or furious and could not the mechanism step twice and not realise this and so send a load of garbage after say 10 keystrokes. And if that was possible, can they at the other end backtrack and correct for it? Its very difficult to double step. The guy on the side , noting down the results would soon inform the key presser. It is relatively easy on an E to step back one. Generally if something went wrong, they'd start the message over again. Its a very positive feel to the key-presses, a very definite single klonk. You can't half press a key without realising it. Q: Did some German officers not align the rotors cortrectly enough . There was a procedure called the Officer Procedure. U-boats used in particular. If you wanted to send a message to the captain, only, and not wanting the radio operator who did the decodings to know about it , then maybe the entire crew. You double encipher . The sender would do an encipherment and when the radio operator decyphered it , the only word he would decode was th eword officer and the rest would be encyphered differently , so garbage if he progressed further. He had to take the E to the first officer and he would put his own set of keys in to get the complete message. There were a few instances where a U-boat was sending and it was the first officer who did both encypherments and forgot to change the rotors in between. That was a give-away. Q: On the news last week a few rotors were found in Fareham at the Navy base and they sent them to the submarine museum I think. I didn't hear about that. There was a machine the naval museum at Portsmouth dockyard . That was on display until about 2 years ago and then it disappeared. I wondered where that had gone. Of about 200 machines left then perhaps about 20 in the UK. Most are at B P and a few in private ownership. I'm aware of all the other private individuals in the UK who own some , nor that many. Simon Singh has one, Mick Jaeggar has got one. The one on HMS Belfast , how old is that machine.? The KL7 is 1960s , produced by NSA, the National Security Agency. You say the E is about 35 lbs. The bigger Lorenz machine looks much heavier, could you take it into the field? That was the Murray code system for teleprinter traffic . The rotors, the machine and its E box should all have the same serial number. Its quite rare to be so. In my one the rotors and machine have the same serial number dating it to 1944 but the box is pre-war and is the oldest E box that is around. When I got it in the first place the box was knocked about and needed repair work. I looked in Yellow Pages and randomly picked a furniture restorer at Salisbury. I took all the labels off the box so it wasn't identifiable and asked him to restore an instrument case. He looked at it and said "its an Enigma box". This was a time when little was known about E . How did he know that. 1/ it was made of German oak , 2 / and his mum worked at BP. He rummaged in the shed and found a piece of german oak, and you can't see the join. Q: How many listening stations were there in th eUK. ? 20 or 30 something like that. Around here Flower Down at Winchester , Scarborough was a big one. Where Menwith Hill is now there was one there. Knockholt did most of the teleprinter traffic there. Q: Why are they so heavy, is it just the mechanics makes them heavy, or purposely made heavy? They were built to be used out in the field so robust and the chassis underneath is a huge casting. Q: did the Germans ever know that there was anything dodgey going on at BP. I got the impression they didn't as one bomb randomly hit the site .? There was apparently something like 8,000 human movements a day in and out of BP and that was disguised in a relatively rural area by having a faux military camp next door to BP, with people arriving or leaving by tarpaulin covered lorries and transfering to BP by walking through a wood. They never did discover BP, if they had they would have flattened it. Q: Were the people at BP allowed to go home? They lived distributed around Bletchley. It was very much a personal responsibility to keep the secret and they honoured that. Q: Were there other places other than BP where people were decoding, it seems a bit silly to have all your eggs in one basket? Not on the scale of BP. Bits and pieces around the UK. There were outstations around BP a few other manor houses. Not really with any intent to spread the stuff around, they just run out of room at BP. Q: When did GCHQ start? That really came out of BP. Some transferred to EastCote in North London and moved to Cheltenham. 2 of the colossus machines evaporated from BP and reappeared at Eastcote as did a load of bombes.

Monday 13 August , 2012 Dr James Dyke - Peak phosphorous. A civilisation tipping point you've probably never heard of.

His blog

3/4 hr talk, 1 1/4hr Q&A, 39 people, including 31 staying for the start of the Q&A

I'm at the university in the department of complex system simulation, I particularly do simulation of the 
Earth, the evolution of the Earth and how life has affected things over geological time. 
I'll be talking about peak phosphorus , peak civilisation.

Venus, after the sun and the moon , the brightest object in the sky, bright enough to see 
during the day. Because of the relative positions of Earth and Venus we only get to see it certain 
times of the year , dependent on which part of the orbit . Sometimes we see it in the east rising befre the sun , 
sometimes in the west setting after the sun. In human history we thought it was 2 different objects , 
the morning star and the evening star. The names the ancient Greeks gave Venus , Hesperus the 
evening star and Phosphorus the morning star, meaning bearer of light presaging the start of 
the new day. the people who caled it Hesperus and Phosphorus are long gone , all we have left is 
some ruins and some cultural inheritance. As with all civilisations they had their time and are 
now gone. All civilisations have a period of growth , then a maximum extent , a peak civilisation , 
maybe peak in terms of their territory , cultural impact or military power. After the peak there may 
be a slow steady decline into history or perhaps a calamitous collapse. 
What will be the future of our global civilisation and the role of P in it. A number of reasons to be optimistic 
about our future and some for not being so optimistic. One dash of pessimism is from climate change.
A visualisation of temperature changes over the last hundred years, colour coded , the average temp between 
1950 and 1980 , dark blue is 2 deg C cooler than that average and red when 2 deg warmer. 
Over later time we are warming up because we are emitting a large amout of  greenhouse 
gases, changing the composistion of the earth's atmosphers. One of the greatest chalenges that future 
humanps will face. There are other challenges. We may be in the middle of one of the mass extinctions on 
earth. Current extinction rates are 100 to 1000 times greater than the background extinction rate . 
We think of extinction in iconic terms like the dodo, hunted to extinction , but most is through 
habitat destruction like deforestation. A tropical rain forest like this or where there was one, 
one of the biodiversity hotspots of the earth we've chopped down half of it and by the end of the 
century about 20 % of it left. We are affecting the hydrological cycle, eg the Aral Sea from 1989 to 2008 went from the world's 
fourth largest fresh water lake to a series of much smaller dour lakes. That sea evaporated 
away because its tributory rivers were diverted for largely cash crops like cotton. 
In a couple of decades that ecosystem was all but destroyed. You won't see fish living there 
any more , profound ecological impact but also economic and social impacts. 
The coastal communities once around the Aral Sea have evaporated also. 
In 12009 an influential study was published in Nature which identified a number of 
planetary bounderies - 9. To keep a global civilisation we must keep within these 
boundaries. They visualised as radiating out from the centre. As far as chemical pollution and 
atmospheric aerosol loading we don't understand out impacts. We can see where the dangers are - 
biodiversity loss , nitrogen cycle and increasingly the phosphorus cycle. 
We seem to be having a large number of deliterious impacts on the Earth system. We 
don't do things well as for the planet we have to live on. To mess things up is a necessary 
function of being alive. eg being alive means running metabolism which means eating food then 
producing waste, we must poo. The poo is a byproduct but a necessary component of running 
metabolism . If food just flowed through you , you would not be extracting any energy 
from it. The production of waste is just as important as being able to eat. 
Food in , wast out, gives an energy gradient and an ability to do work, thermodynamic work. 
The formalisation of any thermodynamic engine operates over a gradient. 
A temperature gradient, for a steam engine, a hot reservoir , the furnace, a cold reservoir the 
outside world , a temperature gradienmt and heat will flow. Hot to cold, and as it flows we 
csan extract some of that heat in order to do work. 
The Carnot Efficiency, which is related to the temperature difference , maximum amout of work and 
efficiency with the maximum temperature difference. So make as ghot and cold as possible 
will maximise the efficiency. Thermal engines cun run over othe rkinds of gradients. 
A gravity gradient, a very steep hill , people falling down it disipating energy and so doing 
work. That work is dislocating limbs/ break bones / render themselves unconscious . 
People do this for fun , chasing a cheese going at 60 mph at the bottom, Coombe Hill 
in Gloucestershire. The winner wins the cheese - thats the motivation. 
There is an important energy gradient going on in the earth. A geological gradient. 
A hot dore at about 5000 deg C, and cooler at the surface 10 or 20 deg. Heat will flow and 
precipitates a range of geological proicesses. Earthquakes, volcanoes, movement of continental 
plates , the transformation of land surface via geology. 
Thermodynamic engines operate on th eEarth's surface in the hydrosphere , the equator region 
is hot and so  a flow to the poles. As that heat flows it drives the Earth weather and climate. 
The dissipation of those gradients to do work is same for organisms. They take in high 
energy-dense food, produce waste, and so can grow. They can grow to repair cell membranes, 
build biomass and to reproduce. That what we humans do too. 
The thing is there is an awfull lot more of us around these days. So we are having larger 
and larger consequenc eon the planetary system. There are more of us, consuming more resources 
in particular its power. 
So population and power extraction on a plnetary scale. 
Some of the population story can be told over my lifetime. Me, born in 1972 , the Earth population 
was a little over 3.5 billion. 40 years on , a little over 7 billion, a doubling in 40 years. 
In a historical context, graphically, going back 12000 years . Most of outr history we numbered millions 
or tens of millions. There are a number of step changes, in the last century and in the last decades. 
Associated with that increase in people has been an increase in food. 
Graphing the amount of food globally averaged for a fixed amount of area, Kg of food per hectare. 
1950 to 1960 an increasing trend but from 1960 onwards the global system starts producing about 
4 times more food. If it hadn't done that there would have been mass starvation. 
Along with this population increase and food increase as come the increase use of 
phosphate rock, mineral P. Going back to 1990 , good correlation, an increase and volatility in 2010 . 
P is a component of DNA, RNA and other important bio-molecules. Without P you cannot grow 
, cannot live. If there is any P limitation on your land then you cannot grow crops. 
Its not the only component , a leaky bucket analogy. 
To raise the level of water in this bucket you need to plug the holes lower down first. If this is P 
limitation, then you can increase the amount of P . This has been caklled the green revolution , plugging the 
of that leaky bucket , for water, P and the other components. So includes pesticides , fertilisers 
such as P and N, water irrigation and high yielding strains and pest resistant strains. If we 
hadn't done all that , many millions would have starved. That system did not come for free, it 
took a lot of energy to run. 
For the period 1790 to 1990 , the energy consumed. Every piece of firewood, lump of coal, 
gas , electricity from coal,gas , nuclear fision , All that energy was used again in the period 1990 to 2010. 
For most of our history we are limited in energy use by are our muscles to do work, or 
muscles of oxen or biomass in terms of firewood , peat , animal dung. Its only in the last centuries 
have we been able to extract energy from  fossil fuels. The exponential increase in energy consumption . 
The question is what comes next. There is much discussion about peak oil . How it will 
play out, what will be the ecological/economic/political ramifications. When you take a broad 
historical over-view then its reasonable to make the assumption that this tremendous increase 
in fossil fuel will be mirrored with a tremendous decrease in fossil fuel use. They will run out and 
they will run out rather quickly. What do you replace them with. What sort of burden do we need to find for 
renewables . At the moment world-wide consumption annually is 50 to 60 TeraWatts. 
The default assumption is that as fossil fuels decrease , renewables will take up the slack. 
The false assumption that exponential increase will suddenly stop and we will collectively 
decide we don't need this additional energy. Maybe an assumption could be 5 times the 
current renewables useage to take over, how can we do that. What alternatives to fossil fuels 
are there. 
The moon along with the sun determines the Earth's tides and then tidal power. Nuclear power, 
fission , I think we can ignore fusion for the next few decades. Geothermal energy , the radio-genic 
heat of decay of radioactive isotopes in th eEarth's crust - uranium, thorium potassium. 
But ultimately for renewables, its the sun. thats not just solar voltaics or solar-thermal , 
but wind is second-hand solar power. The differential heating from the sun is the driver of winds. 
The same goes for hydro-power, part of the hydrological cycle , driven by the sun. 
How to capture all this in the time scale we have - I've no idea, but it is doable. 
The problem with P is that there are no replacements. You can't swap P for something else. 
There was a recent study apparently showing some bacteria that could swap out P for Arsenic . 
Its seems it was not valid science and even if it was the case then its a pretty exotic lifeform. 
The way P cycles around naturally in th ebiosphere is its conained in continental rock and the oceans. 
P enters the biosphere via autotrophic? organisms such as lichens or trees and by the colonisation of the 
land by mainly trees about 500 million years ago. That accelerated the rate at which P is 
taken into the biosphere. They can mechanically crack into rocks and also exude chemicals that 
dissolve rocks, in order to get hold of the growth limiting items such as P. 
When its in say the leaf of a tree , it gets eaten  say by a caterpillar, eaten by a bird, that dies 
recycled by a worm say, eaten by a bird etc. Eventually that P atom will be washed away 
through rivers , into an equatic ecosystem.  That P can be consumed by algae , eaten by krill, then fish, which die 
decompose , recycle and eventually falls to the benthic? environment, laid over by silt and mud 
, sequestered into rock and lost to the biosphere. 
In geological time that P will be returned by subduction and return in millions of years as new continental 
or oceanic crust. But as far as the biosphere is concerned, it is lost. The biosphere has become very 
efficient at recycling P. Its increased the inputs and tried decreasing the outputs, by capturing the 
P and other nutrient limiting items. P atoms can be recycled hundreds of times before being 
lost from the biospere. 
An early 19th century advert for a rubbish carter and nightman also known as gong farmers. 
Gong is old English for taking a dump. Gong farmers emptied people's cesspits. Before 
sewer systems came in, people would urinate and defecate into a large pit. Gong farmers, 
up to their knecks in this excrement would take it out by bucket , to a cart, take to a river 
or port , onto a boat or barge and taken to farmland. Scattered over fiels to increase 
productivity. Urine contains quite a lot of P. Around the end of the 19C posters appeared 
advertising the miraculous properties of guano. Off the coast of Peru mountains of 
guano produced by many generations of seabirds over thousands of years and rich in P and N. 
Within 40 years natural resources like this were completely depleted. The guano peak was 
around 1880 , popular in farming practise world-wide. 
These days Russia and a town called Apertiti ? processing the mineral apertite a mineral 
form of phosphate. How do we couple the P cycle to the carbon cysle. 
When autotropic vegetation like a tree grows it draws down C as CO2 fro mthe atmosphere, 
combines with water and sunlight , producing sugar and a byproduct of O2. In the ocean with death 
of organisms they locked it away , via geology of heating and squashing that C 
is converted to hydrocarbons . In the last couple of hundred years we can drill and make wells , to exttract 
those hydrocarbons as liquid fuels. Then burn them and return the C , thst was locked into the 
geology, back into the air. All to power our civilisation and a consequence of that is we 
can do work such as build a digger and by digging and mining we have been able to access 
P. Previously locked away from the biosphere. We've accelerated the input of P into the system. 
We've been accelerating its throughput into aquatic ecosystems. Its not been recycled 
around as in th enatural steady state system . When it does that as P is a limiting nutrient 
the algal community goes berzerk algal blooms. 
A fresh water lake in China , like other countries, suffering tremendous algal blooms. 
They produce dead zones , a catastrophic effect on these ecosystems. The water running in 
contains P and N etc, produces an algal bloom , die and rain out all these dead algae 
, decomposing in the botttom benthic environment on the sea floor . When they decompose they 
consume a lot of oxygen and you end up with oxygen deprived water , so no life. 
There's a large dead zone in th egulf of Mexico . 6,000 sq miles , in 2006, at the bottom of that 
ocean nothing is alive. The Deepwater horizon spill was an ecological catastrophe but dead 
zones such as this are much more important. Its been going on for some years, but with an effort 
to decrease these dead zones, there has not been much improvement. Its due to the Mississippi 
river, runs through the agriculture heartland of the USA and carries 40 percent 
of all the P that runs off continental America. 
the amount of P in reserves in Gigatons and it seems quite a lot. Thinking about future 
geopolitical implications. We might be able to swap-out oil , but you can't replace P. 
When P limitation starts to bite and Morocco and W Sahara are sitting on the lion's share of 
P resources, what will be the geopolitical ramifications in the next 20 to 30 years. 
At our rate of use, these reserves will not last very long. 
A 2009 report in Nature. So how much time have we got. We've extracted the easy reserves of P 
, how long have we got to work out how to recycle the finite resources. 
The IFDC , non-government, non-pfofit work closely with developers and users of P , 
they think there is 300 years of resources. A resource is not necessarily the stuff you can 
get out. Its the amount they think is there. There is no agreed standard as to how to calculate this. 
This 300 is a summing of all the actors, the companies and countries that produce their 
own individual estimates. It is reasonable to asume that the number is likely to be a bit higher than it is 
to be lower. If you ask the USGS they will say we will hit peak P in 20 to 30 years. A reserve is 
what is in the ground, that we can get to, that is economic to get at now and we have the 
technology now to get at. We can extrapolate technology a bit into the future and extrapolate 
price/scarsity a bit into the future . That chimes with other studies, a 2009 study which 
looked at historical P production . Produce a model curve where the peak may be. 
Here , from th eoil industry is the Hubbert? cuve , the first person coined the term peak-oil. 
When we look at the historical depletion of natural resources then many do follow this curve. 
It is reasonable to assume that similarly with P, large increase in use then followed 
by sharp decrease. And the peak P being 2030 to 2050 or so. There will be a progressive 
decrease in the amount of P that we can get out of the ground. 
What can we do about that as we cannot replace it with anyrhing else, we need to use it more 
effectively . 
Soil erosion blankets. Placed over an empty field or sometimes grow crops through them and they reduce 
wind and rain errosion. Permaculture processes , organic practises , recycling via composting 
and modern day gong-farming - a urine diverting toilet. Diverting piss from faeces at source then its much easier to 
process. None of these solutions is sexy, clever physics like fusion or a Dyson shell around 
the Sun. A lot of the problem with P is not technology but social or political. 
Over 1.5 million people die a year because they don't have clean water. Most of those are 
young children who succumb quite quickly . We know how to save these people , the technology 
is called a well , around for thousands of years. The reasons they do not have the wells is largely economic 
or  social or political. Its inmportant to take a scientific or technological approach but if you 
miss out those other factors , you will not be dealing with the whole problem. 
What has precipitated the challenge of peak P is the incredible growth in human population. 
Doubled in my lifetime so far , it won't double again in that time as its slowing down. 
The numbers added per year peaked in the 1980s with 80million added per year. 
Going down for a number of interactive reasons , prosperity, education, family planning. It 
looks as though the peak population will be around 9 billion around 2050. A reasonable 
assumption is there is something of a perfect storm brewing. So by 2050 then 
at least 50 percent more food required, perhaps more like 2/3 because a large proportion 
are currently mal-nourished. So at least 50%  more water and more enegy . They all 
seem to be pinching us at the same time around 2050. We have to do all that without 
exceeding our planetary boundaries. How will we not increase out footprint on the 
Earth- not at all clear how this will happen. 
The things we have left of the ancient Greeek civilisation are the impressive ruins, archaelogical objectsm, t
heir culture and history. But in planetary terms if you went ahead many milliuons of years 
then there would be no trace of ancient Greece. 
Say an extraterrestrial visits Earth in about 3million years time. They will be largely ignorant 
of the Aztecs or Greeks but they will detuct us because our civilisation , the process 
of  industrialisation , that started in the UK, has spread to the entire globe. It is an effect 
that will be recorded in the geological record. It has been proposed that we live in the 
anthropisine age , they would notice that around this time there was the disconinuous change 
in the Earth's atmosphere. A sudden increase in CO2 , sedimentary rocks from this time will 
show strange trace elements such as mercury or chlorine. things that should not be there 
]naturally. But most noticeable will be the widespread decrease in biodivesity which 
seemed to span the entire globe. Some sort of calamitous event befell the planet and wonder 
what it was but it was ourselves and industrialisation. 
When you understant the challenges of peak P are closely related to the challenge of peak 
oil. the need to feed all these people, the energy to keep our lights on . Then there is a strong 
normative element, noot just scientific challenges , ethical challenges . How much to we 
care about the welfare of future generations, how much resources do we want to set aside 
and how much do we plan for ?. When we take a systems approach a more holistic approach 
then I feel we may be a bit more optimistic about the future fate of our civilisation. 

Q&A

?, a system that maintains the P in the soil?
I've come across it most in terms of C sequestration. James Lovelock proposed that we should 
be biocharring? a lot of agricultural waste in order to sequexter C that would otherwise decomose and entd up back 
in the atmosphere. I've not come across it as a medium for the production of bacterial colonies. 
I've heard of  accelerants in terms of nitrogen fixing. Trying to wean us off the Harber-Bosch 
cycle . I'd be interested to learn more about that. 

The mechanisms you featured for P was replicated in the early years of the last century with 
the Chilean nitrate deposits. That was going to become a limiting factor and that was again 
put to one side by the developement of Harber-Bosch. The scenario that you say, has occured 
previously. Essentially an identical scenario .?
Ironically that is a cause for concern with the current N cycle. We are fixing more N 
than the biosphere would normally be doing. That has been associated with the utrophication ? 
event , not just P but N washing off the earth surface. There is an important argument to 
say, we have seen these kinds of peak problems before , we've been able to innovate our 
way out of them. So for peak P, we just need to find some innovation to get the P 
from somewhere else. But P does seem to be special in that there doesn't seem to be 
anywhere else to get it from. 
We got one "get out free from jail card" it does not mean we will get another ?
A good point. 

Should we be harvesting algae?
Its being proposed for all sorts of things these days - feed us, biofuel source. 
The point is you don't want the P in that environment in the first place. To harvest it 
would require a lot of energy. That energy for harvesting would probably be best placed in keeping 
the P on the land in the first place. That proposal of seeding the oceans with iron in a climate- 
change context because algae draw down a lot of CO2 . Often in iron-poor regions of the oceans 
because it gets gobbled up. Dumping iron filings in the sea produced enormous blooms of 
alga that drew down CO2 . But it shoves the ecosystem around , they produce other "blooms" 
of things that eat the algae which die and decompose and release the CO2 or even methane. 
I think algae can have a role to play. 

So eventually the P ends up at the bottom of the ocean, is it evenly distributed, is it 
concentrated. I'm looking to the future when P will be so economically important , it 
would be possible to extract it from th e deep ocean, feasible?
Some people ar eproposing that. It will be deposited in coastal shelf areas , the run off areas. 
So there are higher concentrations in th esediments, not sedimentary rocks, thick 
layers of mud. So proposals of enormous dredging operations, but will be dredging whatever 
current ecosystems that are in place - disastrous for those ecosystems. I don't know how 
serious they are, the technology is there. Whether the P density warrants the amount of energy 
needed . The financial and energetic economics , I'm unsure.

Is there anything being done about smarter fertiliser end. The thing about super-phosphate 
and agriculture is that they threw it everwhere and no wonder so much ended in th esea. Are people 
getting smarter in how to apply, like slow release pellets etc.?
That lake in China that I showed . A large amount of the eutrophication of these lakes has 
been due to the tremendous amount of runoff. In part due to government policy , subsidies 
for phosphates, so the P fertiliser got very cheap. In the leaky-bucket scenario you put 
more phosphate on , the recommended was say 100 Kg, but it was so cheap then put 
150 Kg on, just ot make sure. Thats changing as its becoming a scarcer resource. 
The 2007/2008 food riots will only increase with the scarcity of P. So if I was a classical 
economist I would say don't worry. As P becomes more scarce , it becomes more expensive 
so we use less of it. But they are now more sensibly using it in China and other places around the world. 

Myself and my wife are currently potty-training my son, pants are down in th egarden and N and P etc 
are distributed back to the soil. Should we all be doing more gonging?
I have young chilfdren and my wife encourages them to urinate on our veg patch, if that helps. 
There are new sexier versions of dry-toilets being produced . In Sweden there are public 
dry toilets, composting toilets. Reasonably sophisticated, usually in th eventing , so 
the air goes somewhere else. Dry toilet technolgy does not have to be unpleasant. If you have your 
own garden you can use your own waste , but no reason why it cannot be more genrally 
collected and used for agricultiural purposes. Should we shit for victory. 
From your graph its contribution has been small. 
Its not been keeping up with population growth. 
Our human waste does not generally end up on agricultural land. It gets treated . 
You can compost human waste and then put it on fields. There are some interesting 
developements on biological processing of this waste, developing on what was used before the 
large centralised industrialised sewage systems. Filtering, eaten by bacteria, aerobic or 
anaerobic bacteria that translate your urine and faeces  into bacterial biomass and clean water. 
The P would run through that and end up in the water table. 

What about changing our eating habits, not eating so much meat? Its not very economical 
to grow grain to feed anamils to then feed us.
From a thermodynamic perspective , its not very efficient. Capturing all this energy from the 
sun , to grow crops, feed the animal that produces high quality protein but dissipates 
heat and methane etc. There is some land you cannot sensibly grow crops on , rocky land say 
where goats can grow and then be eaten. But in terms of using the land that we do use , more 
efficiently then we should eat less meat. 

Is there a fancy organic chemistry process involving P that ensures the P is locked 
up when in the ground as an insoluble form but somehow is made available to plant roots 
, so no run-off errosion problems. ?
I don't know . You can imagine that they genetic engineer a special plant that has a particular 
enzyme . Then you're in th erealms of hydroponics , where you have large vats that you 
grow crops. But you can control the fluids . Effectively it could be a closed system and then 
no run off. But imagine the energy to build that infrastructure. 

[audience member] Thats what biocharr solutions employ. You take the plant waste , turn that into biochar 
and then back into the soil. 
Would a part of that be the production of bacteria / biofilms that 
would be more sticky?.
 Biocharr principle is that it contains micro-holes that contain 
biotic condominiums and all the species can live in there and they  conserve the P in there 
rather than running off into the aquious environment. Algae are also proposed to 
prevent run-offs. Then having developed your , how do you get your P back out , 
an energy-intense process. You can put them in a bioreactor and even get 
methane out. Again all the engineering in all this would be a hell of a challenge. 
10 billion at the Royal Court - very depressing , too much population , too much 
stuff collectively. Basically we have to  use so much energy and resources to get ourselves 
out of iour mess then exascerbates the problem further. I like your holistic 
approach and I am seeing that permacultre is a way forward. If we cannot technofix 
our way out of our fix then we have to power down. 
There are economists that say when oil is $200 a barrel then they will just find more of it, no 
trouble at all. Then sensible economists say I'm with you on resources .
The problem with oil is not that it will run out , even the concept of developement 
without growth , no energetic growth, no material growth , is an anathema to them. 

Have they found P on Mars?
I imagine there is. About 1/1000th of 1% of the Earth is P. Mars is geologically similar. 
Much the same with the Moon but it takes tremendous energy to get there. 
Sometimes you hear of projects to steer asteroids into Earth orbit , as tremendous amounts of 
rare earth elements for semiconductors as well as iron and nickel etc. 
The Google initiative ,funding to n million dollars a project to send probes to the asteroid 
belt and then steer them to Earth orbit, hopefully orbit , not Earth impact. 
(We win either way )
We might all be Martians of course. Because 3.5 billion years ago the Earth and Mars 
were very similar and over geological timescales have interchanged material between them. 
Impacts on Earth , ejecting material with enough energy to escape the Earth and some 
would land on Mars. And vice versa , some Martian meteorites found on Earth. 
A large flux of material between the 2 , so possible life emerged on Mars and tranferred to 
Earth about 3.5 billion years ago. 

How do they deal with the problem , as in the Gulf of Mexico , of little O2 in the sea. ? 
Filter type things at the mouth of the river or a stretch of iron-fed algae or something?
Trying to reduce the amount of phosphate that ends up in the rivers. As such rivers go into 
a delta, you have some kind of sieve or filter. I've no idea how that would work.
I think they are attacking it only aat source. Again the problem is a lot of infrastructure 
and energy. Better not to put it in the river rather than trying to fish it out. 

Is there a parallel problem with potassium?
Potassium is a limiting nutrient as well. Nothing like the scale of problem with P. 

The problem seems to be not a lack of P, as the P is not going away anywhere , its just 
that its not recycling. Its the population, I don't know what you do about it but while 
our population continues to increase , we will have shortage of oil, P , shortage of water 
will be a big one. Part of me says , we are tinkering at the edges , is there a solution?
Its a politically charged issue. Its important to bear in mind when it comes to consumption 
of th eEarth's resources , a small proportion , people like us in th eindustrialised west . 
We appropriate most of the resources. We eat most of th efood although not the majority of 
the Earth's population. We produce most of the greenhouse gases as we burn most of 
the oil. The ecological or planetary boundaries that we've got are largely due to us. 
So say the Amazon. Strong economic and social pressures to chop down all that rainforest. 
But the global climactic impact if they did that would be so severe , that we've all got a 
stake in that region. We've put so much C in the atmospher we just cannot afford to 
burn all that rain-forest any more. 
If you look out of the window, where is the nearest bit of indiginous ecosystem thats not been 
altered by humans in some respect - ancient woodland somewhere perhaps. 
I looked into buying some , they market it as ancient woodland but its not , 100 years 
old or so. None of it left as we've chopped it all down through industrialisation and before that. 
To argue that other people aren't allowed to develop economically is essentially that 
we're all right jack and pulling the ladder up, we got here first. 

On a technological note, on retreiviong resources from the sea floor . Its not as implausible 
as you may have once thought. Nautilus company is using high tec to mine rare earth deposits 
at hydrothermal vents. It would not be diofficult to adapt to general sea-floor mining for P 
as it essentially requires heavy duty strip-mining equipment . The thing about the ocean is that you 
can cheat , in energetic terms. Its relatively cheap to get stuff up from the sea-floor when 
done on an industrial scale. The down-side is the ultimate sink of P is also the sink of  CO2 
. ?
Where I showed that utrophic lake with algal bloom. I think in Germany there was a scheme, 
for where large amounts of P was being run-off into lakes . They were stripping out the mud, 
where there was an anaeoxic process , the algae depleted the O2 , drops up the P in the mud. 
There were dredging out the mud , to pull back the P to avoid it being 
injected back into the system. My understanding is that they just dumped the mud, as the aim 
was to stop atrphing of the lake, not to get the P out of the lake as such. 
I see no reason why that mud could not be processed to retrieve the P. 

Whats your opinion that human developement and peak P are linked in a hysterisis loop?
As we run out of P that creates a forcing , a collapse .
If there was a calamity and the whole systemn fell apart , its an interconnected , dependent system. 
The city of Southampton grows no food, it imports all its food and its energy. A constant 
flux and there would be a large hysterisis loop. I watched "Threads" again, the danger of 
nuclear weapons, BBc film about 1982. Showing the effect on a couple of families after a 
nuclear exchange between USA and USSR. Depressing seeing modern industrialisation bget unpicked. 
The infrastructure is destroyed and reduced to the level of technology of the middle ages. 

What do you think the anthroprogenic inputs to the homeostasis of the P cyscle. There was 
a Nature paper last year which reckoned we had broken the cycle or do you think its still mainainable.?
I think its still mainainable, its not irrevecoverable. If actions were put in place now or 
quite quickly . The residency time of CO2 in the atmosphere is of the order decades 
 there is a lag there. In terms of P input , the momentum in the system isn't biophysical 
its socio-political. Your not even going in the right direction, the current political paradigm is 
a sequence of captainds taking random turns at the wheel of the juggernaut and no 
movement to where you need to be. there is time available in an idealised world. 
People need to get engaged about these issues , yesterday. 

You feekl the situation is political or is there a hard geo-engineering side to it?
I think its largely political - like climate change. Certain political actors , its not that they 
don't believe in climate-change but just not suitably motivated to do anything about 
it. Some people find the notion of geo-engineering controversial becaus eits seems to be giving 
people a free-pass. For CO2 , we need to just engineer something that makes that CO2 
not a problem, mirrors in space , disco balls in the stratosphere . You're then changing the insolation 
hitting the earth. 

Surely the effect of 9 bllion population , such an extreme forcing on the global system requires an equally 
extreme response. Its no longer a matter of fiddling with cycles already present on the earth 
but engineering a smaller population. ?
A problem is that we don't really understand how 
the earth-system operates. We have an idea how the flow of nutrients or chemicals 
move around the biosphere, how the climate works , geological systems but there is 
a tremendous amount we don't understand. Not fuzzy litle bits biut oreders of magnitude in 
even which directions that forcings may go. The nightmare scenario is say at some 
point there will be very extreme weather , or a food crisis much worse than 2008. 
Then a knee-jerk reaction , must be seen to be doing something. 
A Royal Society report on there being a dead cert for aerosol sulphides by 2050 
, the problem with that one its cheap and easy to do . 
I think we have to remember that we're the species chases cheese down-hill, 
we are the cheese-chasers. 

How are scientists like youself engaging with politicians and economists to influence 
them to do the right thing?
The main mechanism is that we work out what we think that they want and we tell them that, 
in order that they give us money so we can do our research . Essentially we write funding proposals. 

Can you give us an example of where this has taken place and the result?
In terms of actual science. I'm currently involved in the plantary boundaries thing. Thats been 
very influential. There was a workshop in Southampton a few weeks ago , where some of the 
authors of that paper attended . Trying to work out , how we take a planetary boundaries 
perspective and then apply it at  aregional boundary scale. We can only operate on the 
problem at a national level. So unless you give an input to national policy makers , then 
nothing will happen. We try to formulate regional boundaries that people can then use 
to inform their policies for forthcoming years and decades. A way to instrumentalise 
or operationalise some of the research so we can make a difference. But its patchy. 
Look at the history of climate change, you have to be careful when you say scientific 
concensus , a lot of scientific bodies have been saying for a long time now its an issue. 
Then the result for Rio was zero . No outcome at all, no binding agreements. 
The finer nuanced problems like peak-P , peak-fossil fuels, food security is a hard sell.

I've noticed around western Southampton the explosion in the number of solar panels. 
Not much but many a mickle makes a muckle. I'm not convinced its come down from on high. 
People thinking this is a good deal. Once such catches on then things can change very quickly. ?
I think its due to the number of companies that will install the panel for free , you can have a certain 
amount of that generated electricity and the rest is fed into the national Grid and the 
company takes a cut. 

Why is there a planning regulation on all new houses? Adding thermal solar wouldn't 
cost much at all.
The German government subsidised solar PV to the tune of 1 billion Euro or so. 
The intention was good , kick start the deployment of panels. But unfortunately what happened 
was that most of the instalation was in north Germany and economically and energetically 
not a good idea. It was justified by saying at least it will start people off, economies 
of scale. The building regulations on thermal efficiciency in germany far excede the UK. 
On one hand you have scientists like me and on the other large corporations with a large 
amount of money they would like to donate to a political party - thats how our 
politcs works. There has been continued resistance from the UK building industry 
against house energy efficiency requirements. 

Have we touched on a way around this political impasse. Expecting conferences like Rio 
to come up with an agreement , with everyone having their own vested interests 
are unrealistic. What you can do is showing in you're own back yard that it works. 
If say in the UK we came up with a system of conserving P. so we were virtually self-
sufficient then we can advertise that to the world, saying therse approaches work. ?
We've done quite well on reducing C emissions - the dash for gas.
A study last year in PAS ? embodied carbon - how much C was moved around the Earth, 
not just fossil fuels but embodied energy. So a laptop made in China consumed an 
awful lot of  fossil fuels, produced a lot of C. So my laptop but somehow the C 
in its manufacture I'm somehow no longer responsible for. When you trace around where the C 
gets emitted , then the likes of the UK has offset manufacturing generated C to China. 
So act local but think global. Ironically the most enthusiastic are the ones most adffected 
by climate change - low lying countries, are the countries with least voice .

I've done the modelling , the biochemical cycles of P. As P and N are intrinsically 
coupled , do you think intrinsically there is a coupled solution. Things like analogues? that can 
lead to recycling large amounts of N , can increase recycled flux and bring in the P. 
So reducing outgoing fluxes and bring back to a hoeostatic point?
There are interesting scientific parts of recycling - it is a leaky system. How do 
you reduce the leaks from the system. There are scientifically interesting ideas 
but I'm not convinced that they're as important as pissing on the vegetable patch or 
permaculture. For many people permaculture is organic farming , it doesn't energise 
people, its not a shiney solution that you can buy or deploy . That may also explain things 
at a policy level . When a government is wanting to fund research , that is big challenges, they 
want comensurate big solutions - some shiney tech. The improvenment in UK PLC 
is not through hessian blankets on th esoil . I think it skews their priorities. 

So we have to go back to previous ages, to live more sustainably?
Not very realistic or attractive. 
Do you have an Ipad or Smartphone. 
No, but I want one.
Good, the thing is once you have one you want the next one. You don't need it but we live 
in a consumer society. We judge ourselves , in comparison with out peers, by material 
possessions. We spend a lot of our time shopping for things that arguably we don't 
need . Thats what our culture is based on. 
James political party, contesting the next general election , no more Ipads, 
smart-phones , hessian shirts , tax on babies, hoop&stick for the children. 
Political suicide and everyone knows it. We like nice shiney things and the first 
person who stands up saying , no , you can't have it.
We would need to craft that message in a way that people would find attractive. 
We need to navigate through consumerism , live sustainably bu tin a way people find 
attractive and interesting. Probably have more to to with interpersonal relationships 
and living in communities . We will all be dead, its the next generations that have to 
deal with this. 

On an optimistic note, we may be able to cheat our way out of this one. Looking at 
the entire situation as a closed system, facing political opposition to being forced to live 
in a more constrained lifestyle. We've made large technological innovations over just the 
last few decades,. In the time gap available before dsome of these situations become 
so serious they kill us off, we might be able to move to technological solutions that 
we simply can't envisage now. We now have Google looking into mining asteroids and similar schemes 
, seem far-fetched now but in 50 years time . Maybe we can dodge the bullets by changing 
the questions. I think the situation will change in the economically developed countries 
like the UK and USA . Whether the third world would be susceptible to these solutions 
is another question . ?
Have you heard of the Singularity University.
A bunch of techno-optimists , they call it a university. Running summer-schools 
and outreach. They think we can innovate and design our way out of these global 
challenges. They have some wealthy friends in silican valley. I hope its not another way for 
people avoiding having to make hard choices. 
Someone will succeed with fusion , or cold fusion or something . One reason to be optimistic. 
The Bill gates foundation is promoting birth control . There is robust data that shows 
that as people reduce say the amount of electricity that they use , energy saving lightbulbs 
, their cost of electricity goes down, a bit more money . So with that money they take a 
short-haul flight to Tenerife. Take bio-fuel aviation fuel, to fly rich people around the world 
and the amount of acres of crops to do this , less land to grow food for people currently 
experiencing food poverty. A zero-sum game . The role of bio-fuels, ethanol in the USA, 
or palm-oil in SE Asia has been an important driver in increasing food prices. 
So replacement of fossil fuels with bio-fuels has increased the cost of food and has 
directly made more people go hungry. 

What if the Sun decided to through a wobbly. I went to a recent Intech talk and there is 
a correlation between sunspot activity and Earth heating. ?
The worrying thing as that the current increases in global temperature have happened 
at the same time as this really quiet period of Sun activity. When the Sun gets its act 
back together we could see a greater change. 
Our understanding of sunspot cycles is too poor to read anything into it. 
Maybe the Sun will help us out and cool us down. 

What sort of research are you and your department working on now?
Most probably , the planetary boundaries stuff. There is this notion of a planetary 
doughnut . Imagine this planetary boundary - biodiversity, climate etc , all the things 
we can't excede because it would be bad news. There also needs to be a notion of a social 
foundation , a social floor/flaw?. If there is 7 or 9 billion people , a need to appropriate 
a certain amount of the Earth's resources in order to give everyone a decent life. 
But not too much or the whole system collapses. I've been working with others 
into how we can operationalise that. The nice thing about the notion of a social 
doughnut that fundamentally its a distribution problem. 
So for climate-change , we're producing a lot of greenhouse gases. But what percentage 
of the Earth's population is doing that. Relatively small percentage doing it but a 
relatively large proportion is affected. So a small section affecting the social 
foundation of a large number of people. S oyou don't need a large number of people 
to make large changes, to hsave a large impact on a large number of people. 
Redistribution has a certain utilitarian flavour to it . When you're trying to engineer 
good outcomes for the Earth-system you want to identify who is having the most 
impacts and where do you want to intervene to have the most impact , for the greatest 
number of people. So the doughnut principle of taking a certain amount but not too much 
seems to be getting some traction. There's a model amnd people in a political 
context seem to be reasonably engaged. So we are taking that and putting it in a regional scale. 
So every region ,. we can access what's their contribution at a planetary 
boundary. What you consider to be a social foundation , perhaps a car or a nice 
house , garden ,TV etc is not the same as somebody else who would be happy 
with a small house and a fridge and a scooter say. Its an ethical concept. How much do we use of 
the Earth and what is its consequences on a planetary scale. How does my footprint 
affect the other regions. 
Do you find yourself veering towards politics?
Not really, I know people who do the politic things , I don't know how they do it 
but they need to do it. If I say these measures are mainly political, and I make no 
effort at politics , then what sort of contribution am I having. But there others out there 
who operate in a political context , for better or worse. I just find it incredibly 
frustrating. 



Monday 10 September 2012 , Dr Paul Garside from the British Library presentation . The Role of Science in the Conservation of Historic Textiles. 1 1/4hr talk, 1/2 hr Q&A, 21 people I was an undergrad at Southampton and stayed on to do PhD, using analytical techniques to study polymers used in natural textiles. Then a researcher at the Textile Conservation Centre which was then based at Soton Uni, subsequently moved to Glasgow. Looking at way natural and modern textiles aged , deteriorated and environmental interaction. Also a lot of support work for the conservators in the unit. So analytic work to make the conservators work more effectively. What is conservation. ("triplet" of the recent Spanish church fresco news item) Illustrates what can happen if you have someboidy who does not know what they're doing, doesn't have the right skills and doesn't havre the right support, attempting to carry out conservation work. Conservation is attempting to conserve historic artefacts , buildings etc, enabling them to survive for future generations. And in the process of doing that, finding out more about them. There is a subtle difference between conservation and restoration. Generally restoration is the process of attemptiong to restore the original functionality to an object whereas conservation is preserving as much of the original object as possible but not necessarily restoring any sort of function to it. But there is a lot of overlap. Conservation Svience. Its a discipline that helps to back up conservation work. It draws on a wide variety of conventional disciplines, particularly chemistry but also physics, engineering , biology , biochemistry and environmental science. For background research , to understand whats going on with objects as they interact with the environment, as they change and deteriorate . Can help in looking for new ways to conserve objects and find out more information about the object itself. Its history, its provenance , how its been used over the years, how its functiuon changed and also to look for things like alterations , previous conservation treatments and of course fakes and reproductions, which superficially may look very similar to genuine artefacts. We can use this science to advise on a number of conservation decisions, by identifying its components , characterising degradation products, suggesting conservation strategies and then back up those strategies with analytical work to support conservators . To advise on appropriate methods of display and storage and to determine what the likely effects of the local environment are going to be on a particular object. It covers a wide range of different materials- paintings , stonework, wood , books and paper which is what I'm now working on at the BL, and textiles amongst others. What are textiles. A wide range of different fibres. Natural plant-based like cotton,flax,hemp , animal based as wool and hair fibres and silks. Wool fibres are made of single cells usally specialised cells which aggregate together to give the final fibre , silk is a single filament of proteinaceous material, much more homogeneous. Principal difference is plant fibres are principally cellulose , whereas animal fibres are principally proteins. Synthetic materials such as nylon, polyester , acrylic etc. Most are derived from petrochemical sources though an increasing , of late, a drive to produce from more environmentally friendly materials. There are regenerated fibres, sometimes called semi-synthetic fibres, a natural polymer material as a basis , broken down into simpler components and reformed to give a final polymer that is formed into a fibre. The most common one is Viscose, made from regenerated cellulose , largely from wasate cotton and wood pulp. Broken down by chemical processes into smaller fragments and reformed as a polymeric strand. There is also regenerated proteinaceous material , less common, popular in mid-20C particularly in WW2 when a shortage of natural fibres. Cotton and wool were taken for military use, so little for civilian use. At that time synthetic fibres had not come into large scale production. So materials like Ardil , formed from peanut protein - a British product and Karnofil? a Gernman invention made from waste meat products. Not pleasant and a great failing that they broke down very quickly. Briefly presented as a wonder material , filling a gap in the market but it turned out they had terrible long term stability problems. Tended to break down particularly in th epresence of moisture . Scarves made of Ardil , issued to troops in Korea and the moisture from breath caused rapid breakdown. Wrap aroud your face for a few weeks and it rotted away. There has been a recent resurgence in popularity with them because of their supposed environmental credentials . Its dubious how green they are, considering the amount of processing required, and even now not particurly good physical properties , so tend to be blended with other fibre types like cotton and polyester. They all tend to share similarities in composition and structure. All fibres tend to be quite narrow , most are 10 to 20 microns in diameter , thicker wool up to 50 microns . Lengths at least 100 times the diameter, all polymeric , all highly crystaline with the exception of wool. This may seem strange as textiles tend to be soft and flexible. Its their crystalinity that gioves them their good physical properties, strength in particular. In general their resistance to stretching. Cotton is about 80% crystaline , remaining mainly amorphous. Flax is similar , silk is about 70% crysrtaline . Synthetic fibres are much more variable because its easier to tune their properties during production. Probably 50 or 60 % crysytaline , remainder is amoorphous and most have a structure where there are small crystaline domains embeded in the amorphous material which acts as a binder . That provides the flexibility and to a certain extent the elasticity of fabrics. The crystaline areas give it strength and resilience. The individual fibres are usually spun into yarns . The tightness to which a yarn is spun is highly dependent on the fibre lengths, the longer they are the less tightly wound to give a coherent yarn. Then usually woven as plain, twill or satin , varying on how the weft and warp twist over one another. Plain weave , an alternating structure , over one, under one. Twill , over 3 , under one Satin , over 7 or 11 , under one. This gives different surface properties and strengths to the fabrics. You can also have non-woven materials, like felts. This can then be turned into objects. I've dealt with a wide variety. Ranging from Egyptian grave shrouds , several thousand years old, made from linen, 19C theatre scenery , military, guild and trade union banners . A set of 18C armory in the Wallace collection , cotton velvet heavily studed with rivets . the space-suit a clooeague worked on , contained mylar and teflon coated glass fibres which have conservation problems very particular to themselves. Furniture , a whole range , from mediaeval to a globe chair from the 1960s. Some problems encountered with textiles and why conservation science is important. A look at 2 silk banners, both I worked on and both from mid 19C. A banner of Prince Leopold , one of Queen Victoria's sons , in dreadful condition, the silk has almost completely fallen apart, impossible to use in its original form as a banner. Compare with hte Korean tiger banner and its in very good condition just some very small fractures. The diffence is not apparent until you look at the fundamental chemical properties of the materials and the way in which silk is processed in those periods. One characteristic of European silks of mid 19C was they were bleached by a harsh method , especially sulphur-stoving, which involved exposing the silk fibres to the fumes of burning sulphur, produsing SO2 that then reacts with moisture in th esilk to form sulphuric acid , thae active bleaching agent. Thge other European process was to treat with metal salts , known as weighting. It gave a particular stiffness and drape to the fabric, making it much crisper. At the time was considered desirable but unfortunately ,these weighting agents, embedded i nthe silk are strongly implicated in the breakdown of the silk itself. They react , especially in th epresence of light, photo-catalytic agents in the degradartion of the silk. So some case studies, objects that I'd worked on during my time at the TCC. The sail from Nelson's flagship , Victory from the Battle of Trafalgar in 1805 . Clothing recovered from the body of Everest mountaineer Edward Mallory. Bagpuss A pair of Freddie Mercury's trousers A 15C eclesiastical tapestry . So some techniques that I use for this sort of work, as a run up to looking closer at these particaular objects. The processes vary according to objects being looked at. If looking at stonework or metal-work then different techniques at your diposal than if looking at organic materials like textiles. Microscopy, both optical and electron. Spectroscopy , particularly IR Chromatography of various sorts Mechanical testing to look at physical properties. Artificial aging and the use of surogates, using replica materials to give a better understanding of what is going on with genuine artefacts. Microscopy allows us to distinguish between different sorts of fibres , plant fibres have similar forms and a hollow luminate? centre , wool fibres scaley surface, silk and synthetic look broadly similar featureless and smooth but there are other ways to distinguish between them. In cross-section silk is rounded triangular , synthetic have a wide range of cross-section depending on their intended use. Ranging from cylindrical cross-section to elyptical, star-shaped, hollow centres,dog-bone, bar-bell. A refinement is using polarised light , brings out more features, V and X shapes on the surface distinctive for flax. Similar to use for forensic purposes . Electron microscopy enables study in finer detail, eg flax fibre picking out more surface detail including surface debris and surface damage . using EDS Energy Disperive X-ray Specroscopy , giving an idea of the elemental composition of your object. So on top of the morphology you can get the composistion . IR spectroscopy can be used as a sort of fingerprinting technique , obvious differnces betweee , here, silk,cotton, polyester . Individual chemical bonds have specific frequencies at which they vibrate , similar to the frequencies of IR radiation. The frequencies are absorbed , characteristic dispersional frequencies, so a C-C bond will vibrate at a different f to a C=C double bond , C-H etc. Those vibrations are also influenced by the immediate chemical surroundings of that bond. So in theory you can get a lot of detailed chemical info. Not just the chemistry but how the structures are laid down and oriented . Plant fibres are cellular and the cells are laid down in helical structures in the fibres. The orientation clockwise or anti-clockwise and the angle of winding is very characteristic of pareticular species of plant fibre. Flax and hemp have angles of wind of about 7/8 degrees but in opposite directons, sisal about 22 degrees, banana fibre about 30 deg, choir / coconut fibre about 70 deg. By including a polariser in the IR spectroscopy to restrict to the bonds that will interact with the radiation , only those bonds that are aligned with the angle of polarisation of the radiation , will give a signal. So can see how the polymers/ chemical structures are oriented within the fibres. So plots f on x-scale and angle on the y-scale . Can be used to identify the angle of cellulose in a sample and thereby identify the plant species. Useful if your sample is so degraded that all the surface morphological features , that would otherwise identify it, are indistinct or obliterated. You are studying the internal construction of the fibres using this technique. Freddy Mercury's trousers We had these in for conservation, from a collector who had bought thenm at auction ( famous image of red trosers). They wanted to know what they were made of , how they could be preserved and how best stored and displayed. Using spectroscopic techniiques, identified both materials, a faux leather made of polyurethane over a cotton backing material and using microscopic techniques could see how it was degrading. The polyurethane was going brittle and fracturing and was pulling away from the cotton base layer. In some areas the delamination was complete , and lost completely. I could then give recommendations to the conservator who would then work on it. How it could be displayed without further damage to the material. What sort of local environment of temp and humidity would best prevent further degradation. Bagpuss Bagpuss is held at a museum in Kent. One of their most popular exhibits. They wanted to know they were preserving him in the best possible way. so what is Bagpuss made of. I got in contact with Peter Fernon ? who made all of the puppets and props for Oliver Postgates's productions. He sent me an offcut of the original fur material. It turns out its acrylic on a polyester backing, we were able to identify the stuffing as well and also the nature of the framework inside. And then the best recommendations. Clothing recovered from the body of George Mallory He died on the attempt on the summit of Mount Everest in 1924. His body was not found until 1998/9 by anothe rexpedition. They retrieved various bits of clothing from the body. A jacket he was wearing . From the state of the body it was evident he'd died falling from an avalanche, probably roped to his companion Erving? It wasn't clear whether he'd reached the summit. The team who found the body made clams that he was improperly prepared for the sort of expedition he was carrying out. this upset his surviving relatives. We were talking to his great-niece. She got these clothing remnants from the retrieval team and asked us to look at them along with a team at Leeds University with a speciality of lookingh at clothing for extreme environments. We worked out the components to enable replicas to be drawn up and made. My role was to determine the fabric and any treatments . The jacket and trousers were made of a tough but light weight cotton material which had been weather-proofed like a Barbour jacket. A light weight sweater under and 3 shirts, identifying the fabric in each shirt, silk, cotton and a light weight wool one. We gave this info to the Leeds unit, they reconstructed and tested them . The sort of climb Mallory was attempting , effectively a sprint from th ehighest camp to the summit and back down. They behaved much as modern climbing equipment would. So it was possible to refute the claims of him being improperly prepared. So an interesting footnote in the history of climbing as well. While they did not have access to modern synthtics , were used in a thoughtful and sophisticated manner. A 15C altar tapestry Two main parts , the altar front which depicts the Tree of Jesse , the family tree of King David. Above is the super-frontal . There were doubts as to whether the two parts originally belongerd together. There was some oddities about the way things were constructed. One oddity was the metal threads. The branches over the figures were made of metal threads. There were odd disjunctures, bright gold metal and changes abruptly for no good reason to a very dark material that has no metalic lustre left in it. So why was this occuring. For the superfrontal, it didn't seem to fit stylistically with the frontal and a suspicion it had been added later to make both parts , the same width. the way it was constructed , we were able to take a number of samples from th eback of both parts, as there were lots of loose threads from the weaving process. So pieces a few mm long, without causing any aesthetic or physical damage . A variety of metal threads, constructed in a variety of ways. Mostly had some features in common, composed of metal strips wound round a fibre core , some had single metal over a core and some had multiple metal filaments wound in different directions around the fibre core. About 14 different ones we could identify. A subtlety of appearance was achieved varying the tightness of wind , more or less metal wrt tohe fibre core and also the colours from white through yellow to orange and red. Giving differnt tints to the lustre of the metal thread. Looking at their composition and structure , nature of the fibre core and the metals used. For the fibre cores. Featureless smooth fiibre , silk. A possibility if it was repaired recently , or a modern reproduction or fake then it could have been synthetic as similar appearance. IR spectroscopy showed a spectrum that clearly showed it was silk, by comparing the spectrum to known materials. Then electron microscope looking at the metal threads. Gold and lustrous sections under the scope , the surface is almost completely undamaged. The blackened area is a blistered corrossion surface . Doing elemental analysis via electron microscope is gold with a small amount of silver alloyed , no signs of corrossion. In the other areas , we see silver copper and sulphur . The metal filament is silver gilt , a thick layer of silver/copper alloy that had been coated with a thin layer of gold , so cheapening by bulking out the gold underneath. Gold is unreactive but silver and copper will react readily with sulphur forming the characteristic blistered grey/black corrossion surface. This would have occured largely in the the last 2/3 hundred years , kept in environments where there was large amounts of S pollution, from coal fires and industrial polltion. The corrossion blisters force the very thin gold layer off the surface and is lost. two different types of thread, one thicker surface layer and better attached to the underlying silver sustrate and pollution cannot access the silver layer. The poored threads although originally a similar appearance , the gold layer is much thinner , more prone to damage , by cuts or scuffing, the pollution can then access the silver layer , the corrossion forces off the gold, exposing more of the silver until almost all the gold is lost. The tapestry had been put together in a very piecemeal manner . the materials had not bee nsourced together , made using bits and pieces laying around, about 14 different types of metal thread. Some chosen for their different apppearances but others simply had different structures. Most of the threads had been made from gold or silver gilt filament wound round a fibre core, but some were different. Cheaper in construction, instead of silk at the core, there was flax , with electron microscopy looking at the gilt surface and the underlying surface. The gilding was a much cheaper process , powder gilding , where gold dust is simply beaten into the surface usually over an adhesive base layer, usually an animal glue, such as rabbit-skin glue, cheaper than using continuous gold foil. The underlaying material was not a silver material but something organic , microscopy showed it to be eithe rpaper or gut , which was widely used at the time. Spectroscopic analysis showed it was cellulose and so paper-based material. The next area of interest was the gold border around the super-frontal. The conseverters and art historians had identified as being suspect, the style was different. It looked to be gold but there were areas that looked more like copper. Could have been gilded copper material , similar to gilded silver but due to the way the gold was becoming detatched then that was unlikely. Using EDS it was a brass, a copper-zinc alloy , Pinchbeck ? brass developed only in th emid 18C by exposing copper objects to zinc fumes, so the alloy is formed on the surface but not in the bulk , which explained the odd pattrern of deterioration where some areas appeared to be gold , but were brass, and neighbouring areas where there was damage and abrasion we can see the underlaying copper. So the unmatched dates gave a better idea of the history of when the 2 parts may have been put together. Silk As we saw in the 2 banners I mentioned before. Is prone to quite catastrophic damage. A late 18C silk which ahas been weighted-treated with metal salts to improve its texture and drape. Weighted in this case with tin chloride which is known to act as a photo-catalyst. So it breaks down silk in the presence of light, particularly UV. So looking at individual fibres I wanted to get a better idea of the deteriation of the textile as a whole. To start off we need an understanding of the underlying chemistry and microstructure. Silk is a proteinaceous fibre. A protein called Fibroin ? and the bulk of that polymer consists of 3 amino acids, Glycine , Anomine and Cerene ? and these constitute a 6 amino acid repeating motif. GAGAGC repeated to make up 60 to 80 % of the bulk of a silk fibre. Thids simple 6-peptide repeat forms zig-zag backwards and forwards secondary structures of the proteins. A structure known as an anti-parallel beta-sheet. These beta-sheets agregate together into beta-crstalites, small crystaline domains within the fibre bulk. One of the features is they are all oriented in exactly the same direction. Along the fibre axis withing the silk fibre. The remainder of the construction proteins form an amorphous matrix which binds the crysalites together, like an adhesive or filler. As a result the fibroin and silk structure as a whole is highly crystalised, 60 to 70%. I was interested to know whether it was possible to look at the orientations and determine from that , what sort of degradation the fibre as a whole was in. If it could be used as a simple analytical technique. Started with conventional spectroscopy and the common feature of all proteins when looking at the IR spectra are 2 amide bands , amide1 and amide2 bands. The precise postion of these and their shape changes subtley with the nature of the protein you are looking at. They always appear at about the same positions and roughly similar ratio. But there is subtlty within the 2 peaks and can pull out more information abouyt the underlying material. Used polarised specrtoscopy. Like the plant proteins , getting an understanding of the way the cellulose in the cell walls is wound, clockwise or anticlockwise and hits helical wind angle . Trying similar with silk you can see the difference between the non-polarised and polarised plots particularly at the 2 amide bands. Comparing where the axis is aligned with the polarised radiation and at right angles. Produces 2 differences in the amide bands. From conventional spectroscopy it is possible to derive a crystalinity index, giving an overal crystalinity of the fibre, proportion of crystaline to amorphous material. What had not been done before was looking at the orientation of the crystaline material in the fibre and trying to relate that to degradation. So derived the crystalinity index X for a number of fibres that I';d artificially aged for different periods and X does not change very much. Perhaps a slight fall in X with aging. Probably within the experimental error. With polarising and a ratio betweeen the 0 degree and 90 degree spectra which I called the orientation order parameter ? when looking at that over the same aging period of the same samples this OOP showing how well ordered the beta-crstalites with the fibre axis, this dropped off quite dramatically. Suggesting that as the material aged, the beta-crystalites , in the fibres, were becoming less well aligned with the fibre axis. Then enlarged to far more samples and a wide range of conditions and plotting OOP against breaking strength. Using breaking strength as a non-specific measure of degradation. Strength wil lreduce, regardless of how the fibre has been damaged, high temp, high humidity , micro-organisms , bacteria, mold , light exposure. So useful measure without having to look at specific types of degradation. So as aged/degraded. the strength reduced and th eOOP reduced. Quite a bit of scatter in the plots , what you'd expect for a natural material. But it is a method that can be used, looking at a single fibre , or just a few, so not going to cause a problem with either the appearance or the physical stability of an object. And get a good idea about the state of deterioration of the silk as a whole. So useful to conservators where just looking at an object may not tell them what condition it is in, how it can be handled, what sort of display it could be given. Could it cope with being suspended from a manikin or must it be laid out flat. This sort of data can be used to back-up thos esort of decisions. This OOP reflects the breakdown , not of the crystaline regions , but the more chemically accessible amorphous regions. Accessible by any agent that comes into contact with it. As the amorphous matrix breaks down then the crystalites can become increasing less-well aligned with the fibre axis. This formed the main thrust of my PhD and I went on to develope it in more detail. Similar analysis can be applied to other kinds of fibres and polymeric materials. The sail from HMS Victory. The biggest object I've dealt with, 24 metres along the bottom and 17m high. The only surviving sail from Victory, Nelson's flagship at the Battle of Trafalgar in 1805 . Its the fore-top sail. Over the coarse of the battle it was extensively damaged , by musket and cannon fire , about 80 holes from that. A mast behind it , was shot away, and fell throiugh part of the sail, ripping it down half its length. It was heavily impregnated with gunpowder residues , which are chamically aggressive and harsh. Subsequently it suffered over 2 centuries of storage and display. It was displayed in 1905 at its centenary , hoisted onto a mast mock-up. It was flooded at least twwice while in storage in a chest at Portsmouth dockyard. For a while it was also used as matting in a naval gym . A suspiciously square hole in th emiddle probably is from the period when the Royal Navy was helping to train the Japanese Navy and a section was cut out to present to the Japanese ambassador, late 19C. It had quite a hard life, in fact the reason it survived probably because it was so damaged. Sailcloth was incredibly expensive at the time so any sails after about 2 years of use , at sea, they were retired and dismantled and re=used to repair other sails. This one was so damaged it was not of much use for spare parts. It weighs between 4 and 500 kilos , we never got an exact weight for it. Physically getting access to it , interact with it , was difficult. We got involved prior to the 2005 bi-centenary. The TCC was involved to do conservation and analytical work on it. Conservation was mainly cleaning, extensive mold growth on the surface , and more subtle forms of damage. A lot of the damage was deemed to be intrinsic to the object, telling part of the story. So repair of that damage was not deemed suitable. So stabilised the sail , so it would survive without too much future damage. The first problem was how to lay it out in the warehouse in Pompey Dockyard, but is wasn't large unough to unfurl the sail. So part of it remains rolled up on an inflatable boom , made by an oil-spill boom maker. So rolled softly, avoiding problems from hanging or being folded. All the conservators had to use positive pressure masks as clouds of mold spores could be seen coming from it whenever it was touched. So a H&S hazard. We took some samples of the dirt for further analysis . We were given permission to take small samples from areas of pre-existing damage. We wer elucky as the sail was so heavily damaged , lots of loose threads, not performing any structural purpose. Agreement between the Navy and conservators came to the conclusion that the loss of these fibres would be more than made up for in gaining a greater understanding. We were also able to take a section of fabric an inch square from the ripped section, a piece that had become almost detached anyway. Again it was decided that the loss of this piece would again be made up for in understandiung the object in its entirety. Electron -microscopy exploring fracture surfaces of the flax fibres. A large variety of fracture surfaces. Some of them neat tears from one side to the other . Some more ragged at a steep angle. If it was heavily deteriorated then the flatter squarer fractures. If in better condition then miore of the ragged fractures. The fractures occur between points of weakness in the fibre , like tearing perforated paper. Fractures in the cloth occur between areas of damaged fibres. In a severe case then can fracture right across the object. For the situation of less damage then the tear will occur in a more hap-hazard fashion. We could see areas of defibrolation , where the cellulose is wound helically and when they degrade and pull apart you see the small agregations that form the fibrola elements in the fibres, forming strand like structures in th edamaged fibre itself. We also have significant signs of mold growth in various areas. We had about 10 samples in total and had to work out the correlation between these individual fibres and the bulk properties of the sail. We use surogates. Materials that replicate genuine artefacts as best as possible but produced ourselves , in large quantities and can assess in destructive ways the microstructure and chemistry . For th eVictory project we had 3 sets of surogates, modern linen sail-cloth from a company called Banks, modern sailcloth from a ship called the Standart? a Russian reproduction of the flagship of Pete rth eGreat of 1704. A full size replica, used at sea , and similar to the Victory one, perhaps 2 years lifetime if lucky. When the sails were replaced we got in touch withthe group running the ship and got a large piece from them. So similar exposure at sea to the Victory one and a similar sort of period. And some artificially aged samples , produced in the lab , using a regime selected to mimic conditions the sail was known to be exposed to. So samples heating and drying, exposed to brine , simulated intense sunlight, and intense humidity. We could compare the data from those specimens , including residual strength , tendency for the material to slip , elasticity, ability to recover from being stretched and compare it with the data from the small number of Victory specimens. Then looking at the properties of the bulk surogate material , how the Victory sail itself maybe likely to react. We could look at the amount of force it would take to make the fibres in th eVictory sail to rupture , an extreme effect. Subtle forms of damage, where individual fibres in a yarn slip past one another . The way polymeric structures within a fibre can slip past each other. To certain extent this sort of bulk slippage is recoverable. When you release the load they will return to original shape. But you can also get permanent slippage, creep, when the three stages of slippage occur, within the polymeric structure, within the yarn and within the fabric as a whole, occur to such an extent that when you releas ethe load , it no longer returns to previous shape. Permanent deformation. We wanted to make sure that whatevver display method was chosen , this sort of permanent distortion would not occur. There were 3 methods proposed for bi-centenary display. Laid out flat, supported on an angled surface, or hung vertically from a mock-up of a mast. From our physical data, the strength was uniform across the sail , which is a good sign but some localised weaknesses from th edamage in battle and mold growth from less than ideal storage. We showed the vakue of the use of surrogates and that there was good correlation between the properties of individual fibres and the bulk properties . The sail did have enough residual strength to support its own weight if it was hung from a simul;ated yard. But if it was domne then it would undergo a permanent deformataton over a period of a few months. We concluded it should be fully suported horizontally or at a shallow angle. Yhats the way it has been displayed for the last 7 years now at Portsmouth Dockyard. A very satisfying piece of work as we could see it all the way through. Scientific techniques of a variety of kinds provide an important role in the conservation of textiles and heritage objects as a whole. These analytic approaches can inform on conservation treatments , appropriate display and of storage. Also important information on the provenance of objects , to identify past conservation, alterations , reproductions and fakes. Q&A I was amazed that in silk, the crystaline structure of the fibres was aligned with the axis of itself. Is there anything you can say about tthat , how does the silkworm do it? Its largely the result of the process of extrusion. Largely the same as modern synthetic materials. As they are extruded from the bulk polymer to form filaments aligns with the direction of extrusion. Its a bit more complicated than that , a combination of the processes involved in making the secondary structure , so the formation of the crystalites as the protein itself is generated in the glands of the silkworm and then the extrusion process as its using it to form a cocoon. Now knowing the structure and what gives it its strength , is it possible to do something to prevent it from degrading or restore it? There has been some attempts like that, using enzymes such as transcutanamaze? to build up an additional protein structure to reinforce and consolidate the silk. Been quite successful where all you have there is the silk. More problematic when you have other materials, so perhaps layers of material where only one layer is silk or things like buttons , rivets , stitching threads. Treatments that work for isolated silk fail to work well with silk artefacts. Also problems with dye-stuffs and othe rtreatments, reacting badly with them, to discolour or to bleed. Sometimes the metalic weightings poison the enzymes that you want to the consolidation process. One of the tenets of conservation now-adays is minimum intervention, because its not always apparent what conservation treatments may have over the longer term and what information you're loosing from an object when you intervene, are you loosing information from the chemistry or structure that you cannot get at now , maybe accessible by analytic techniques of the future. A lot of current conservation work is remedying past conservation treatments. Its only relatively recently that conservation has become a skilled academic discipline, before that it tended to be people with limited skill-set. In the area that I currently work of conserving paper and parchment , previous conservation tended to be done by book-binders, skilled in book-binding but nothing further. More damage tended to be done by enthusiatic amateurs, doing more invasive and less-well informed conservation treatments. As in the fresco I showed at the beginning. Certainly in the mid-20C when synthetic material s were considered wonder materials , they would last for ever. Such materials were then applied to various artefacts , for instance there was a brief vogue for lamination. Which was pretty dreadful , partly because of the heat involved and partly because it involved fusing not particularly stable synthetic polymers to the object itself, which is then next to impossible to remove. Soluble nylon was popular for a consolidating material , slightly better long term stability. Again very difficult to remove as introduced as a liquid and can become itegral with the object by reaction. It does improve the strength but you loose flexibility and drape. Over longer term the nylon tends to degrade more rapidly than the material you are trying to preserve and introduces all manner of problems of its own. Were metal threads originally and over the centuries , I'm assuming the silk is stronger than the metal threads and how does it fare differentially over the centuries. ? The technolgy of metal threads changes quite a lot over the time they've been used. Started as pure precious metals , then in mediareval times gilded silver and gilded copper , silver/copper and the like come in. Then you start to get membrane threads thin metal over organic . Membrane threads survive the worst, although they are more flexible and therefore in theory more sympathetic to the bulk fabric , in fact they fare poorly, becoming brittle and fall apart quite quickly. Probably why they were used in any great extent for only about 150 years in late madiaeval and early Renaissance. After then you don;t really see them again. The metal threads with solid metal filaments generally last well unless they are subjected to a lot of flexing. So good survival in things like tapestries , flat, hung , not folded or moved usually. On clothing they wear very quickly where there are areas of most movement. Because the metal does not have the intrinsic flexibility or suppleness that the fabric does. The fine rthe fibres, the better they survive. How do they make those, machines that they make them? Came into use in Greek and Roman period , classical period, starting with foil and cutting thin strips with a knife. Later periods you get more sophisticated techniques using using bladed rollers to cut threads. Then wire drawing becomes more sophisticated. The round wires are then passed through rollers to flatten them. How do they go about wrapping them around the natural fibres,a machine for that? As far as I know they used a twisting technique much as fibres are spun into yarns. I'm a steward at Winchester Cathedral and the Winchester Bible? that dates to 1160 ??? and it looks as though it was made last week. Absolutely no degradation. Our visitors cannot believe it is 850 years old. Its made of parchment and all illuminated . Why no degradation? Parchment is a remarkably durable material , partially tanned animal skin and under the right conditions it will last incredibly well. A few of the artefacts I work on at the British Library are the Lindisfarne Gospels and one of the copies of the Magna Carte and these are in remarkably good condition when you consider their age. The Lindisfarne Gospel where the parchment still contains a lot of its natural flexibility , you can turn the pages without causing any problems. The illuminated work is still bright and in good condition. The thing that is the main threat to parchement is its very susceptible to damage by water and moisture. It undergoes a process called geletanisation , going from collagen a skin protein to gelatine which is much softer and water soluble and hydrolosis with water. If parchment is kept in such a way that it is not exposed to damp conditions , and away from sunlight then generally it survives really well in deed. I suspect your artefact has been keps indoors, not exposed to sunlight and generally not exposed to moisture or high humidity, to start gelatinising or equally mold growth . At the other end of the quality scale. What causes the yellow and brown spots on books like paper-backs. ? A variety of different processes and the processes aren't fully understood. Sometimes caused by tiny fragments of metal from the process of laying down the paper from the grids, inclusions of steel or iron. You can get localised discolouration from some of the sizing agents, alum and gelatine . Localised mold growth can cause the problem also . Research is still being carryed out on these foxing marks. While on paper, I'm probably an enthusiastic amateur in this area. I've a lot of data manuals from the 1950s and 60s that go seriously brown from acidified paper. I knoe there is fancy expensive patented processes , spirit based for dealing with that. First of all I photocopy to retain the information and then wash with a washing soda solution and dry them out , that stabilises from going any browner but the paper remains friable and breaking up at the edges. Professional conservationists use tissue but is there anything as an enthusiuastic amateur I can spray on or add to the washing soda to give the paper some structural strength again? Once its got to that state its difficult to restore its original strength without using some sort of stabilising material. In the British Library a thin layer of tissue is added over the surface. Unfortunately it stems from th enature of the paper , wood pulp papers were introduced in the late 20C and they are very acidic and break down becoming yellow and brittle to the point where its impossible to handle them without the paper disintegrating. In contrast with traditional paper making which was rag paper using old linen or cotton fabric broken down and pulped for the individual fibres and then reformed into paper. That will last for ever near enough, I've handled ragpaper from the 14/15C which is still fully flexible. Equally I've handled paper from as you say , the 60s and 60s, where you can't handle it any more without bits of it falling off. While the dacidification of the kinds you mention will significantly slow down future damage , its very difficult to consolidate the paper without actually adding a physical stabilising layer , because its reached a point where there is so little cohesion left in the paper , with little left to bind it together any more. Is there anything added to thast patented spirit based process that reinforces the paper, I know there are things like anti-molding agents added at the same time? There has been some work done , much like I was saying for silk of adding materials that polymerise within the structure of the paper but its very difficult to do with bound volumes because you always risk the problem of sticking the pages together when you use these sorts of processes. So often can only be carryed out on single sheets, so time consuming , space and resource intensive. From th econservation perspective it also runs the same problem that you're adding somrthing new and you don't know how well thatr will last and what affects it will have on the original components of the object. That research has not reached a point where it can be used widely . Accelerated aging processes are reasonably reliable expanding years to centuries ? Up to a fashion. Dependent on what sort of aging you carry out. The 3 main types of artificial aging you can carry out are thermal often in the presence of high humidities , light aging visible and sometimes including UV, and pollution in the form of agents that an object is likely to experience. All have problems, light aging is probably the least problematic , increase the intensity and you get a simple increase in the rate of reaction which mimics quite accurately. So expose for a week , light equivalent to 20 times natural sunlight , that would more or less be the equivalent of exposing to 20 weeks worth of actual sunlight. Thermal is more problematic. Useful in that as you increase the temperature you get increased reaction , increasing most effects that the object would naturally experience but there is a limit. You start to introduce problems that would not occur naturally , you often get state chenges , physical changes in some components of the objects that would never occur in normal aging. With higher temps you start reactions with higher activation energies which again you would not see in natural aging. Increase the aging too much and you start to see all manner of additional processes. Artificial aging is useful but you have to be aware that an awful lot of problems with it. And limitations on informing you as to what the real object would be doing. Do you use any sophisticated statistical techniques ? There are a large number, tending to vary with the people and their background skills doing the jobs. The one I've used to a large extent is called Principal Component Analysis which enables you to correlate data from lots of different experiments. Unrelated data sets that apply to the same object. Then draw models on a statistical basis , enabling the prediction of the future of objects. Personally I've not used statistical consultants. I know people doing more fundamental research on the chemical processes have done so with considerable success.

Monday 08 October 2012, Dr. David Hooper
Atmospheric refractive index, fundamentally important for lower-VHF and UHF radars - including the Acrobat radar at Chilbolton and for trans-horizon radio wave propagation.
Sunsets and mirages, which are also affected by atmospheric refractive index.

Dr David Hooper from the Mesosphere-Stratosphere-Troposphere (MST) Radar at Aberystwyth, MST and Chilbolton Facility for Atmospheric and Radio Research ( CFARR), Hampshire CFARR Powerpoint 1hr, Q&A 1/2 hr, 26 people I'm with the STFC Rutherford Appleton Laboratory, I'm affiliated with the Chilbolton facility near Andover, but mainly with the NERC MST , NERC is the Natural Environment Research Council who fund anything to do with the atmosphere , earch, geology or biology. The title today is Who says that light has to travel in straight lines? About atmospheric refractive index . The basics of refractive index Atmospheric refractive index , in school you are taught that it does not really have one, indistinguishable from a vacuum , that is approximately true. But delve into the details and very small changes have a big effect. I'll wrap up by looking at the significances of refractive index in the modern world. Instruments that rely on refractive index and also some subtle effects from something so small. Pic of the stem of a wine glass , showing the bending of light. Making a crude lens and seeing something behind. Raindrops on a spider's web. Each drop regardless of size is acting as a lens. Showing upside down images of th esky , trees etc. Its the refractive index that causes the bending. Rainbows - fundamentaly a result of refractive index and of water/rain drops , you could have a whole talk on rainbows. Halo, taken from an aircraft window . Formed of colours like a rainbow but the sun is in the centre, so the opposite side of the sky to a rainbow. Refraction but through ice crystals Pic of the obalisk in rome , covering the sun , a ring around . So examples of refractive index with ice or water having some sort of optical effect. What I'll be talking about, water doesn't really come into it. Pic of the setting sun and there is a ragged edge, this is caused by change of refractive index of the air and only to do with the air. Sinusoidal wave, showing amplitude vertically and horizontally the direction of propogation. Superimposed vertical lines, called phase fronts , imaginery lines. In a minute I'll get rid of the waves , leaving just the phase fronts. The distance between 2 of these fronts is the wavelength . Animation of electromagnetic wave, sinusoidal pattern propagating horizontally. A series of wavefronts travelling along . The refractive index of a medium or substance is a ratio measure of the speed of light in a vacuum to the speed in the medium. When light passes through any medium other than a vacuum it basically slows down. So for air 1.00 indistinguishable from a vacuum, a simplification because my talk is based on that not being quite true. Its true to 2 decimal places and need to add 2 more decimal places before I see the effect. Then at the other end of the range diamond with a refractive index of 2.42, so the electromagnetic waves are more than half as slow, thats what makes diamond bendy to light and its sparkle and different sorts of glasses around 1.5 to 2. Animation of wave fronts only between 2 media of refractive indeces 1 and 2. At the interface, if perpendicular, the fronts slow down not loosing energy just delayed, so if anther interface back to 1 then they'd speed up again. Running backwards would be the same. Approach at an angle , the beam changes direction at one end first and slows down , relative to the other end. Snell's Law. Angle Theta1 in the first medium and theta2 in th esedcond sine theta1 / sine theta2 = ratio of refractive indices. In this case going to denser medium then the angle bends in towards the normal to the interface. Air to air then no change in direction. As the second medium index increases then the change in direction increases. Equation involving small changes in the refractive index u from 1 we define refractivity of N , N = -(1-u) * 10^6 ? Then there is a density term and a humidity term, electrons in an electromagnetic wave, forced to oscillate , they re-radiate, giving a delay. The more dense a material the more the u increases but a small term , involving P pressure and T temperature and from the gas laws P/T is proportional to densty. The humidity term involves e which is the partial pressure of water vapour related to relative humidity. The humidity term is important at radio frequencies. In the literature it says the humidity term is not so relevant when you get to the wavelengths of visible light. Not really defined at what point it ceases to be relevant , but the humidity term although smaller than the density term turns out to be important . Pressure basically decreases exponentially in the atmosphere, and temperature in degrees kelvin changes only about +/- 10 % throughout the depth of the atmospher so the density P/T is also in essence decreasing exponentially. My focus will be on the lower part of the atmosphere . Here shown up to 100Km, where the atmosphere is 1 millionth the density at the ground it is this area where meteors burns up. The atmosphere does not really disappear it just progressively becomes less dense. You heat the atmosphere mostly from below , sun heats the ground, ground heats the atmosphere and a decrease in temperature as you go up . Then the stratosphere , familiar to us as the area involving ozone and UV radiation. Ozone here absorbs UV fro mth esun , heating the atmosphere there , so an increase in the middle. The Thermosphere is somewhat similar but its also getting X-rays from the Sun . It looks as though the temperature increases rapidly but the atmosphere there is so thin its not particularly hot in that sense. How weknow the temperatures up to 20 or 30 Km is balloons and radio-sondes. A 1m diameter balloon with electronics under . Fill with heliuum let go and sends back signals of temp,pressure and humidity. Some data from radio-sondes. Density term and humidity term from ground level upwards, these up to 13Km . On a good day can go to 35 Km. Chosen a plot where the humidity is about 100 % all the way up, so that term is as big as it can be. So the density changes exponentially and basically that is what the refractivity does in parts per million, only up to about 300 ppm. The humidity term is smaller , 1/5 or 1/6 so may not think its important. But we will come on to see when it changes sharply it dominates over the temperature term. So the refractivity decreases going up through the atmosphere and it has the 2 terms. A plot of a different radiop-sonde ascent. Where there is a temperature inversion. Typically it is moist below and a sharp decrease above the inversion and a relatively large change in th erefractivity. A third plot with inversion again but with more variation . Some examples where you can see this with your own eyes. A figurative view of the earth and the atmosphere and a series of banded colours , very figurative, overscaling the lower atmosphere, with broader bands outward , demonstrating the exponential nature of the refractivity. So a source of electromagnetic radiation out in space , could be the sun or a satellite. The receiver on Earth could be looking at light or radio waves. If the signal comes through the atmosphere , 2 things will happen. A small delay because if u changes from 1 , the radiation travels a bit slower but the key thing is if its coming down vertically there is no change in direction of propogation . Progressively lower elevation angles of the source , then related to the difference in u although small , most change is near the ground . Also as the incident angle in the first medium gets larger , the change of direction gets larger. A special case of the curvature of the atmosphere , it will curve in as it comes through the atmosphere . Putting real numbers of 1 and 1.03 and making theta1 as big as I can then about 10 degree difference in that example. For the real atmosphere I have to add 2 more decimal places there. When you think the sun as a source of radiation is on the horizon its actually just over half a degree below the horizon, about .57 degrees , varying a bit. The key thing is that change of direction is slightly bigger than the width of the sun. You think you are looking along a straight line but its actually a slight curve. If you measure the rate at which the sun is passing through the sky then you can pick up this effect. The other effect is the sun deviates from being a circle , of the order a 1/6 or 1/7th of the diameter. Take a good picture, take out a ruler , and measuring shows it up. The distortion is linked to the sun being below the horizon. I took a second picture involving a thin low cloud layer and the sun about 10 degrees above the horizon, mid winter. Same lens etc and certainly a circle. I once happened to be passing through Birmingham when there was a partial eclipse of the sun and the same sort of thin cloud. It allows you to see features on the sun that you would not otherwise see following the advice of never looking directly at the sun. Change of propogation direction for an extra-terrestrial source. You could get similar results for a terrestrial source like a radio transmitter tower. The numbers are a bit different if the source is outside the atmosphere or inside. Plot between 90 degrees and 0 degrees of incidence , deviation goes up to about .57 degrees a small change but with the sun you can see it. The effect changes quite sharply in the first 10 or 20 degrees of elevation . After 20 degrees a very gradual change. So the key point is if you are looking anywhere other than the zenith you will have a slight change but at low angles then the change is relatively big. So the sun is half a degree in width and the effect at the horizon is .57 , the bottom of the sun is being brought up measurably higher than the top of the sun, you get a compression more at the bottom than the top. If you're an astronomer you can time this effect from taking measurements. A plot of this compression factor vertically so 100 percent when vertical and even at 10 degrees you will only have less than 1 percent . You have to be down to 2 or 3 degrees above the horizon before you see this effect and 10 percent distortion. 2 degrees is 4 sun diameters. If you know the effect is there then you will start to see it, even without photography and measurement. Some other strange effects that you should be able to see. By the sea you have long flat horizons. A sequence of 6 still images of the setting sun and irregularities around the sun edge , small aspheric ? layering. Close to the horizon it looks like we are breaking an egg an inferior mirage. You are seing a bit of the sun coming back up. You often see this on nature programs when showing a sunrise but they must be reversing the film and showing a sunset because the sun goes the wrong way if in the same hemisphere. Long lenses will emphasise these jittery bits. Mirage effects The key thing here is sharp changes in temperature , inversion. A superior mirage where the change of u is elevated up in th eatmosphere you usually expect a decrease in density / refractivity but where there is an inversion you get a sharp decrease . These effects also happen at radio wavelengths . The object appears to be higher than it really is. An inferior mirage you will be more familiar with a decrease in density but near the ground particularly above roads you see shimmering. A narrow part of superheated air next to the road and a sharp decrease at the bottom. You think you are seing an object on the ground but it is above the ground a sort of reflection but actually a refraction. What you are seeing is lower than what you think it is. What looks like water on the road, what you are typically seeing is the sky. The bollards in the picture look reflected ie inverted , you would not usually have that artificial reference to see. Perhaps less than half a meter above the ground is the heated air . You often see this effect with an upwards curved road so you need to have your head low down or bent legs. Repeat picture of the mirage with bollards but with the camera at normal veiwing height rather than lower down of the previous pic and the mirage has largely disappeared. Quite common at the brow of a hill even when not particularly hot. A bigger scale version of that. Looking down the coast off west Wales at Aberystwyth and in th edistance the Prsselwy hills of north Pembrokeshire. So a few tens of kilometres. the hills in the background, a long flat bit between the dark sea and the dark land is a thin bit of orange. The sea was warmer than the air . Morgan Le Fey , the half-sister of King Arthur , known as a hocus-pocus merchant , so much so that even if she did not exist she has a phenomenon named after her Fata Morgana . More a variant on the superior mirage , stretches things out and a towering effect. People thought that witchcraft was involved with conjuring islands to come out of the sea and go above the horizon. Pic taken be a friend of the sea , a lower line , a weird layered band that has been drawn out of the sea, tend to be very dynamic and don't hang around for very long. It tends to be colder weather . Another one in the Swedish Artctic and when it was extremely cold and an apparent hill in the distance is only a few metres high, looking like a mountain. Although these u changes are very small, you can see the effects of it. Some high-tec equipment that relies on this. Anyone looking at stars at night , particularly low down , say at the seafront and they shimmer around. Due to turbulence mixing the atmosphere , generating small irregularities in the u, a bit like heat-haze shimmering. So for astronomers its awkward but for other scientists who can detect it , it can be very useful. Chilbolton, as well as the huge dish , originally for radio astronomers but about 20 years later it got adopted by atmospheric scientists. Fully rotatable azimuth and elevation so can scan through the atmosphere. When you stand next to it , it has a nice swishing sound . 2 different views taken with the Acrobat radar at about 1000 MHz , meteorological radar sensitive to rain and snow but can sometimes pick up clear-air radar returns. That term does not mean absence of cloud , but by "structures" caused by changes in the refractive index, twinkling . 20 km range and 4km in height , doing a slice through the atmosphere , and a lot of visible structure from turbulence. Middle of the day , sun heating the ground . Then a horizontal scan , slicing through convective cells , same instrument but different point of view . Buzzards and rooks etc going around and around in clear air and if they rise then you know they have found some convection. Same with glider pilots. Withhte radar you can detect these rings where the convective cells were. With convection it can be very dry in the lower part of the atmosphere , convection generally moisture is important , involving latent heat , water vapour can store a lot of latent heat and when it condenses it releases that heat and so drives the convection. Animation from our sky camera with a rainbow and convective clouds , as well as going up they sometimes go down . It can suddenly just take off and get rain. GPS antenas , receiving signals coming down to the ground , going through the atmosphere and slight delays that I referred to from u variation. Density changes in a fairly regular way and by measuring pressure at the surface you can model that pretty accuratrely. That leaves one uncertainty which is the water vapour. So it turns out that if you take measurements from a number of satellites instead of having this uncertainty where the water vapour would through you out of your posistion in the normal GPS useage , you can turrn it around , from a lot of ground measurements you can then calculate what is happening withthe water vapour . A large scale plot of over northern France where the changes in colour, from a network of GPS receivers showing localised areas of moist air. Also shows in the intensity where you hav ethunder . Convection cells , meteorologically , are very dynamic giving rain , thunder and lightening . There is a network right across Europe . So what was a problem for GPS people , trying to accurately get posistioning is very useful for atmospheric scientists. The MST radar , at very low frequency compared to weather radar . The acrobat radar at Chilbolton is run on a campaign basis , all the time , for measuring wind but fundamentally sensitive to this refractivity change. In modern science you sometimes comer across things that you cannot really anticipate. Refractive index turns out to be very important to high finance. About 1200 km between the New York and Chicago stock exchanges. For years people had been using fibre optics and suddenly they have gone back to using microwave links. In modern high finance people trade at computer speeds, miliseconds can mean big profit or not. So they want to get their trades in as quick as possible. From th eNew Scientist article 6.55 mS for IR light to travel through fibre optic cable, about 1.3 so about 1/3 slower than through the air. For the air 4.25 mS so for shaving off a couple of mS it pays for them to go through the air . For thirty years thinking fire optics was the best thing ever. Q&A Your inferior mirage pic, was that an effect of the optics of the camera, it showed a green area , was that associated with the green flash phenomenon? I have to say that the green flash is one of the least impressive of all such phenomena. Its so brief, and you think did I see that or not. Sometimes you get a change in u dependent on the wavelength of the light , a rainbow is a good example. The reason you get the spread of colours due to small change between the blue and the red light. In the atmosphere you also get a bit of separation . The reason sunsets are red is a diferent process , scattering . The green flash is when the very last bit of the sun is on the horizon and the green , how much is the eye-brain system and how much is in the real light . So you might get a bit of blue at the end, in this separation and eye-brain may interpret as being more green. The sun can be so bright , even right on the horizon that you cannot be sure whether you are getting an after-image effect in the eye. It can be photographed. Its just a fraction of a second, suddenly goes from whitish red to green, only just long enough that you recognize the effect. Why is it more noticeable in the tropics? I've only every seen it at Aberystwyth several times. In the tropics there is a lot of rain and rain flushes out the atmosphere. In the tropics the sky can be very fuzzy . In Brittain you get blue skies like nowhere else because we have so muchrain, it washes out the dust. Maybe after tropical rain you have a clearer atmosphere. In India when the sun is about 1 sun's width above the horizon it drops into the haze. You were going to explain the radar setup in Wales? All those big Yagi antenas about 4m tall . It looks unusual as it is lower frequency than most radars , MST at a bit lower than 50MHz , domestic fm about 100 MHz , tV about 400 MHz, mobile phones about 1000 MHz and weather radars , that appear on weather forecasts tend to be several GHz and are so very susceptible to raindrops. So as soon as tyhere is raindrops they cannot see any clear air scatter whaeras low frequency is not susceptible to raindrops and you're seeing clear air scatter the whole time. MST type radars are often called wind-profilers. Thats the biggest job we do with them, measuring the wind. The radio-sondes is still the standard technique for measuring the wind , it get blown downwind and you track how quickly it moves at height. With our radar we monitor all the time but perhaps launch a sonde every 12 hours or so as its quite expensive. We update out wind every 5 minutes. We see a lot of details, structures in the wind patterns and the atmosphere generally. Over the timescale of just minutes , not seen with sondes. It tends to be academics looking at the radar data , as research topics , but the met office also takes our data to feed into their numerical preduiction model. For very localised things , as their computer modelling gets more and more complicated , more powerful, they need to get more fine-scale data. So our radar is very useful to them. Extreme weather is often very localised within tens of km at the most. So very damaging winds, extremely heavy rain its often small scale. We had a tornado at Aber, just a few miles down th eroad , we were upset we didn't see this tornado , then we realised that if we did see it then it would have been the last thing we would have seen with the radars. Just 3/4 km away we have photos of the roof ripped off the buildings. One of the most destructive thing with tornadoes is not the wind but because the pressure is very low and buildings can literally explode , as overpressured compared to the outside. apparently you get more tornadoes in the UK than USA but they are all smaller. I do have a former colleague who works in Oklahoma and every house has a tornado basement, that are used a few times every season. You also get hailstones the size of golfballs there, again driven by convection, cold air from the Arctic meeting moist warm air from the Caribean. I'm intrigued by optical astronomers and their anti-twinkling mechanism of adaptive optics , large collectors made of individual usually hexagonal segments and actuators that can deflect each panel . They shine a laser into the sky and create an artificial star near their point of interest . How much time have they got to simulate the turbulence and refraction effects , process all that and actuate the actuators to correct for the light coming down . ? For an astronome rthe turbulence can be quite a problem . I was talking to an astronome r the other day about that graph where the change of direction comes important , he said astronomers will always try and look at something when its as high in the sky as possible by choosing the right time of day and season. If they can avoid observing in th elowest 20 or 30 degrees from the horizon they will. With their laser systems the processing is almost instantaneous. Obviously with air turbulence it is a random effect , you can quantify that statistically , like a lot of random things but not able to measure it entirely, the whole field. To a certain extent you can predict especially in a high pressure systrem so little wind component to the turbulence. Turbulence is due to 2 main things , heating the ground, so that will tend to die off at night and turbulence from the wind. Roughness of the ground will induce turbulence in the lowest km or 2 . There is a term called cat's paws over the sea , white patterns on the waves, tending to be circular propogating across the sea . Also seen in field crops , its not fully random , billowing patterns, structural and rotational. So most prevalent during the day and with strong wind . Astronomers will try and be as high as possible for a number of reasons , including having less atmosphere above them. For winter stars , one to look out for is Sirius the dog star, near Orion below a bit, when I was an undergrad. Sirius is one of the most twinkly and brightest star, maybe one of the closest . But I've seen it twinkling like a trafic light and I would swear it went through red,green and blue. I had to confirm with someone else this serious twinkling going on. I asked the lecturers and no one could explain convincingly. Some had the theory it was related to the green flash idea and dispersion of colours. The other idea it was to do with the response to colourr in the eye , you need something quite bright to activate the human eye colour receptors and then movement of youself can introduce distortion. Sirius is also low down. Is there an observational difference between planets and stars? Stars are so far away they are effectively point sources. Look at a planet you can see its width. They won't tend to twinkle in the same way . A point source going through the turbulence , it will move around in effect. With a planet you are slightly defocusing it , lots of dots in your eye effectively. Can you tell pollution or the chemical composistion of the atmosphere? In the stratosphere you have ozone absorption , absorbing UV , I believe in a narrow energy band . For a source of say sunlight you will not be taking out chunks but lines where the ozone is and that changes with the height. It can tell you 2 things, about the earth's atmosphere and the sun's atmosphere. With stars you often use spectroscopic techniques to see what is there and what's not there. So you can then tell what's in the atmospheres or the gas clouds. Can it be used for Earth pollution? There is the Dobson photometer and other instruments in the way of passive instruments, looking at what comes down. The Seance ? device, French, for the ozone and nitrous chemicals, different lines for different gases. Chemicals released at ground level often get attracted to the boundary layer can fill up with those chenicals but they can escape by being washed out by rain and you may want to look more horizontally. That would give a nice wide range of monitoring compared to say one of the pollution monitors in town which is right next to a major traffic junction which cannot be representative. ? The shapes of buildings can produce "hot-spots" . One thing studied these days is urban meteorology , buildings act like valleys and hills , channelling the flow and can get stagnant areas and if the council is monitoring pollution there their figures might go through the roof. Monitoring like smoke alarm internals , small radioactive source and scintillation and smoke particle interaction. You could equally use a laser beam . I was intrigued witht hat Iceland volcano Eyejafalocal that went up a year or so ago , all Europe's airplanes were grounded. I routinely look at the data from one of the local lidat meteorological stations , a beautifully clear day but the lidar system interpreted the dust overhead as mist.? I was in Aber when that story broke , showing some undergrads around and the uni of Manchester operate a number of lidar systems in Aber and we had a panic phone call from the Met Office asking if we could detect any ash. The Met Office have a number of off-the-shelf lidars called Cielometers , like shining a torch into a cloud. But they are quite sensitive to volcanic ash. They had about 50 of these instruments but they were not networked in or calibrated for ash. about 6 uni groups operate lidars and they jumped-to sharing informatioon and were very clearly able to detect the dust clouds. We saw it with the Ceilometer in Aber for 2 or 3 hours. Some of the more bespoke systems could monitor and track it for longer. Spelt Ceilo rather than Sealo for seals etc Thinking of animals , you had pics of buzzards there. What sort of monitoring system do they have? Around my part of Oxfordshire we get rooks and at this time of year we se "black smoke" enormous "bait-balls" of rooks and jackdaws circling around together . When a kite or buzzard is doing it you know why as they have good eyesight . When you really only eat is wiorms you don't need to get that high, I think they just enjoy it. I suspect they must be able to feel it. Combined with the visual cue of seing others doing it. Feathers are probably good force detectors. There are probably other visual cues like knowing it will convect abopve a black tarmac carpark. You've reminded me of another thing that ornitholgists would never have known until radar came on the scene. Air traffic radar around London and every evening the Starlings come in to roost from the countryside around London. There are syncronised circular waves , with time-lapse film of the radar screens, that totally mystified the early radar people , these 4 or 5 circular waves over an hour or so the diameter of London and then just disipate. ? If you go back to the old literature , MST radar borrows expertise from different fields . One was from early radar 20s and 30s stopped by WW2 but at the end of WW2 there was heaps of surplus radars. This was picked up by people like us for atmospheric radar . In the early days anything they didn't recognise they used the technical term angel. The starlings was one of those . Clear air echoes, u irregularities , that was also an angel that took a bit longer to figure out. Starlings are a bit more obvious. One of you radar images , did I pick up a sinusoidal pattern in the radar returns that suggests the result of wind going over hills? Mountains are quite important in an airflow. If it can go round it , it will probably go round it , but if fast enough it will go up and over. It will then tend to oscillate downstream called a mountain wave or a leewave . In trapped conditions we can see it over 100km easily , starting over Ireland. It very much depends on conditions in the upper atmosphere , where the MST comes in as we measure the vertical and horizontal velocities. A lot of mountains in Wales. Sometimes you see it in satellite image patterns . In Aber if the wind is from the east and so over the Cambrian mountains . I see it over Oxfordshire and there is nothing there big enough to kick it off. You would not see the mountain wave effect in the horizontal plane, but in the vertical. Glider pilots like lee-waves bacause its another situation where you get lift. Is this why the facility is at Aber? It could have gone to Pembrokeshire on an old MOD site but they occupiers decided not to vacate . The principal investigator happened to be at Aber and a field just about the right size , total chance. The big antenna array is very impressive close up , 400 aerials , the sort of thing conspiracy theorists get into a froth about. Its probably good that its in a valley rather than by the sea because of the radar effect called clutter. Clutter is a fixed target that you don;t want , as in wind turbines and military and civilian radar . The sea also gives clutter , the waves on the sea . If the sea waves are a half wavelength of the radar you get a return. They used to make a sea-state radar . Upside down rainbows? You get haloes around the sun, on a good day will be a full circle , 21 or 22 degrees is the magic number for the geometry and the ice-crystals acting like prisma. If you only see the vertical bits atr the edges they are called sun-dogs. Sometimes you can just see the bottom segment which would be an upside down rainbow. Its hazy high cloud of ice crystals for that. Therre is also iridecent clouds , candy colours of pinks and greens , more of a difraction effect. If you are in an aircraft you could see a full circular geometry. Think of an imaginary line joining the sun , through your eye into the earth. If the sun is high then the rainbow drops below ground level , so mid-day mid-summer you won't see a rainbow. If the sun is one the horizon you get the biggest arc or rainbow . If you are high enough in an aircraft you may see a circular rainbow. The key difference between a halo and a rainbow is the bow has red on the outside and a halo on the inside. For a halo you have to be looking towards the sun. Ids it just me who cannot distinguish indigo and violet in a rainbow , taught about rainbows in physics at school? Apparently indigo is in there because Isaac Newton first came up with the nomenclature for rainbows. He was religious and into alchemy and he liked the number seven as its a Biblical thing. And he decided there must be 7 colours. So in school we've had for hundreds of years falacious mnemonics for the rainbow and Richard Of York Gave Battle In Vain and then Sir Olivers Horse Came Ambling Home To Olivers Aunt the trigonometry one. A rainbow is a spectrum , a continuum , the fact that you see distinct colours is due to the crudity of our eye-brain system. You can't see yellow though. Indigo is not a word that gets used for anything else other than remembering colours in a rainbow and a dyestuff.

12 November 2012 Dr Marie Johannsen presentation, Southampton Uni: The different ways DNA can be used for medicine and diagnostics, including super fast DNA testing. 23 people, 1.5 hours interspersed with Q&A This is my first talk to a general level audience , so I've made several breaks for you guys to ask any questions. I'd rather people understand what I am talking about. A plug for the Dara O'Briain , Science Club , its really good, he has a PhD in astro-physics or something like that. last weeks was on DNA. I've worked on DNA for the last 5 or so years, all my degree certificates say chemistry. What is DNA and what does it do. Like how I introduce myself by saying what I do rather than what I'm made of, I will concentrate on what DNA can do. Schematic of some of the internal structure of some DNA , 4 different units. Instead of their chemical make-up shortened to being called T,G.C and A. You get what is called Watson-Crick base-pairing , T will always have an A , C will always have a G. So if you have one strand , the other will be its negative , have one and you should be able to work out what the other one is . With the 2 strands together you have the double elix arrangement What is known as the central dogma of biology is that DNA makes RNA which makes proteins. In the cell is a nucleus and in the nucleus you will have 2 strands of DNA , a couple of metres long a surprising length consider it fits inside one cell. They will have about a billion base-pairs in sequence. This is the blueprint for life ( in a few years I'll have to stop using that analogy as no one will know what a blueprint is). Like a blueprint it doesn;t change, most of the time. It just sits inside the nucleus of a cell where it is quite well protected . There is machinery in the body that can copy it, split it apart like a zipper and then use building blocks to create copies of it in a sense. Not exactly a copy in a sense, as from TAGC the copy will be the complement ATCG, the opposite arrangement of bases. From one copy of DNA you get a lot of copies of RNA that transfers out of the nucleus and into the cell and will be translated in the cell into proteins. It is proteins that really does stuff in the body. DNA just sits and is a template, RNA can have som,e functions. RNA via other machinery will make proteins , making your muscles, skin , the enzymes that send signals around your body - signals to produce insulin or need to digest something, say. All of that happens via proteins. Q: The DNA does it stay in the nucleus or come out into the cell? It stays in the nucleus and the RNA is made and exported from the nucleus A lot of the time a disease is caused by too much of a protein being made so you want to stop a protein being made , a bit simplistic . Where DNA medicine comes into play, do you want to bind? the DNA , the RNA or the protein. Most conventional drugs will bind? the protein , by a lock and key interaction. A pocket in a protein that a drug fits in, or a protein has a prorusion that a drug fits around. That stops the protein binding and affecting a change in the body. A lot of biology is interpocking puzzle pieces, disturb one bit and they fail to bind and wheatever they were there for , won't happen. One bit of DNA makes lots of bits of RNA , makes many lots of proteins. It makes sense to stop this at the RNA level instead. Stop the RNA making the protein in the first place. If you stop the RNA being translated into a protein then we should be able to target a disease with more specificity and an easier process theoretically. Protein and drug interaction is often like jig-saw puzzle pieces , lots of pieces looking supeficially the same but you need exactly the right piece to fit. To make a drug fit a protein is much trial and error approach. Perhaps a thousand different candidates , screen them for which one works best. For the gene route to protein, you often know exactly what sequence the gene has , so in theory to target it , all you need is the complement. So you just need the sequence that will bind and you know it will bind. But of course it doesn't always work like that. Two examples of how you can interfere at the RNA level. Antisense, a short piece of DNA , a very short piece. Perhaps a billion bases of DNA tends to get translated out to RNA in smaller pieces , maybe a couple of thousand long and then the bit that actually codes for a protein is often shorter , usually from a hundred to a thousand units long. These are 15 to 20 long so how do they work. They obviously do not cover the whole section that codes for the protein, only covering part of it. The RNA that encodes into protein is known as messenger RNA . Once the message is read then there is not much point inthe messenger hanging around,. If the messenger stays around then more protein will get made and that can lead to didsease. There are things around the body intended to cleave DNA-RNA hybrids , that is a duplex which has one strand of DNA and one strand RNA, they are not supposed to be in the body any length of time. An enzyme called RNAzeH ? , which any time it sees such a hybrid it will cleave it. Sometimes that is not what you want it to do and you can change it so instead of leading to cleaving, what you get is a block or you can make it skip certain pieces , known as Serik ? blocking. That can either prevent a protein being made , by being in the way or it can change what the protein theat comes out as . Taking part of the message and blocking it. Like censoring a letter part is obscured by black marking and won't get read. This is relevant to the disease Duchennes Muscular Dystrophy . Its carried on male chromosomes , only boys get it, leading to muscle wastage and by 20 they're in a respirator and by 209 they are dead. Its caused by a mutation , a change in the code for a protein . The protein you want to make has a specific code , in this case there is an error in the middle of this code which is basically a stop, So instead of reading the code all the way to the end it stops and part of the protein gets made , in this case a protein used for making up the grouping of muscles. Half of the protein does not act as the intended "glue" and as a consequence they cannot make new muscle. So not a case of too much of a protein but too little . You can't just mutate someone's DNA to correct things, not yet anyway. So you block out the part of the message that says stop . The rhybosome will read the first part , then skip the part that has dropped off. You still get a protein that is shorter than you are supposed to but it will be longer than it was before. because the stop thsat was in the middle has been removed. You still have muscular dystrophy , just a less seriuous form, one you can live with. Its not a medicine that exists yet , something that is currently in developement . The other example is SIRNA , small interfering RNA. This is RNA not using the mechanism of DNA-RNA hybrid . Doubled short lengths of RNA , about as short as before , they bind with a protein called RISC RNA Induced Silencing Complex. You pick out one strand , the other strand guides the bits of RNA that you want to cleave . Again directing machinery that is already exists in the cell , directing it precisely to the target you want it to cleave. This is a process already in the body for dealing with RNA that has already passed on its message or needs to be regulated. Just a slightly artificial bversion of the process. In theory this would work for any protein . With most drugs once you've tied it to a protein but want to target another protein then you have to think of a completely new approach. The idea behind DNA medicine . Any protein has a genetic code behind it , so if you work out a way to target the genetic code , you can target any protein without needing to change your approach. But there is only a couple of drugs based on this technol;ogy on the market and people have been working on this for 10 to 20 years. The main challenges are 1/ DNA in the body is not exactly one long strand that you can attack at any point , either like a nicely rolled up ball of yarn or the mess after a cat has got to your ball of yarm. You can target only any bit that sticks out , anything that is in the middle or otherwise hidden it will be difficult to target. Most of the time we don't know how its rolled up, so trial and error , make it up and test to see if it works. 2/ Cell walls are made out of lipids , so fats. DNA is water soluble . Anyone trying to clean up a frying pan without soap will find that water does not penetrate fat easily. So you need something to poke a hole in the cell membrane in order to get your drug into the cell where it needs to work. Anyone who watched the Science Club program would know you can do this with detergent but then you dissolve your cells . That doesn't make you any healthier. Q: Cottage cheese blended with Omega3 that makes the omega3 fat water soluble. Again a sort of emulsion thing. Not something you want to happen to any untargetted cell. You need to make a small hole in the target cell and inject the DNA . It could be the same mechanism , like viruses, that lets say influenza into your cells. There is stil la problem of holes poked in your cells in general , not easy at all. If you use something from a virus then the chances are that your immune system will attack it . That is the big challenge . they do use detergent, very small and very targeted deliverers. I presnted it as one gene, makes one protein, makes one disease , and most of the time its more like 1000 genes makes 1000 proteins , makes one disease. There are some diseases that genetic medicine will work for , some that it will not work for. For those ones where it does work , it can be exceedingly clever. As soon as we get that pesky cell entry problem sorted it will revolutionise health care. Q: When the DNA is enfolded , I'd like to say knotted, but that is not correct is it. Is there some rules in the way it can and cant get enfolded, some sort of organised structure to it, not totally random? There usually is some structure, it is tucked around histomes which are represented usually as protein cylinders that the DNA is then wound around. Quite often you are not just targetting DNA because all of those problems with cell entry, they apply also to once you are at the nucleus then you need to get into that to target the DNA. DNA tends to be rolled up in a structured fashion. But RNA in the cell , there are rules to how its rolled up , they are not well known or well understood. You can have something that once you know what the structure is , you can work backwards and see why it is that structure . But looking at a sequence will not tell you which structure it will fold into. Several possible forms it could fold into, thats why I'm likening it to a knotted ball of yarn. You can untangle it , but you cant look at your yarn and say if I add acat , then this is what I'm going to get. There are rules but often not known until afterwards. Q: I'm trying to make a distinction between enfolding and knotting , a knot involves twists and overlaps . However much you pull it, its not going to de-knot itself. I take it its not looping on itself, in that if you got hold of each end and pulled would it undo? Most of the time , yes. But not always the case. Some would be entangled within themselves , not drastically but simple types of knots. Q: With the deliverance, if you were to insert your magic RNA not magic, its science science is magic, if you insert it into a cell of an embryo , and it has an effect say on muscular dystrophy , would that be replicated in all the other cells or would it fail to duplicate when the cells divide.? I don't think anyone has ever tested it with embryos . Its like any drug that is in a body for a whiile, it gets degraded. Its not a permanent change, only a change as long as the little bit of DNA or RNA that you added, hangs around. Like any drug it will get broken down and excreted. The idea is that because there is less RNA , that each bit of RNA will give rise to hundreds of proteins , you should be able to add less to get the same effect as if you had one that bound a protein. Thats another challenge, the stability of drugs. I make a lot of DNA and RNA of approximately this length in my lab. I wouldn't do it because they cost a lot of money to make , but I could just eat them , they would do me no harm , nor any good whatsoever. Because by the time they made it , more or less , to the back of my mouth , they would be broken down. You need to alter it quite a lot, adding blocks and protection along the line to make it last even 10 seconds or 10 minutes in the body. It doesn't hang around, doesn't get replicated . There might be a few excepptions but in general, no. So as its quite difficult to hit targets inside the cells , a lot of DNA medicine has focused on diagnostics. DNA base-pairing , it makes for very effective diagnostics, in the sense that if you know what genetic sequence encodes for a protein and you know what your protein consists of , its a fairly simple translation . You can rationally design a probe that will bind to the sequence that you have. If you know the sequence of particular AGC&T then you only need to add the other part to your probe. The key is not finding something that will bind with what you're looking for but finding a way you can see it. Most of the time you don't have many copies of your genetic material and they're all very small. One process that works quite well is known as super-fast DNA testing. Why does it have to be fast. This is to do with what is called Point-of-Care Diagnostics, which means basically that we tend to be quite forgetful . You go to a doctor for , in this instance clamidia . So you go once a year or once every 10 years , if you have reason to think you may have it. Clamidia does not necessarily lead to any symptoms. So you go to your doctor and have a test. They send it to a lab, takes a couple of weeks , then you have to call your doctor for the results. You may have forgotten in 2 weeks . For some people , if they don't have any symptoms , or if they had symptoms but those disappeared before they got the results back, they may not go back to the doctor to pick up the antibiotics in question. In those 2 weeks they may have transmitted it sexually to quite a lot of people. Also to eliminate the stress of waiting for a test result. Much easier say submitting a urine sample, going in to your doctor surger, and 20 minutes later , on leaing, the result is ready. That is almost what they are able to do. How does it work. Clamidia has a genome , you're not looking at the patient's DNA , you're looking for any clamidia DNA or RNA . In a urine sample there would not be enough to find it or see it, detection is the problem. Fisrst you amplify it by PCR . Gives between 10 and 100 copies and amplify in about 20 minutes, to 15000 or 100,00 . In the mix you have probes which will send out a flourescence signal when they bind to a target . So a bit of clamidia genome , make it accessible and its unique . This sequence is in there , unique to clamidia and not part of a person's DNA. A probe that is bound to its target. It has a helix structure , the flourescent parts of it , they are stretched out, far away from each other and then they give a flourescent signal. The sample is heated up , making the probe fall off. When the probe is on its own it will curl up , and the flourescent parts when close to each other the effect disappears. So you go from a high signal to a low signal on heating . That way you are not only testing thatit is present but the temperature at which it falls apart is specific to specific lengths of DNA, a double test. The last topic, goes away from base-pairing. This is not just an interaction where a T binds an A and a G binds a C and you can also go about rationally. Something that can be used for medicine and diagnostics . Known as aptimers . A nasty latin/greek amalgum , from apta- to fit around something and mer - a small bit or unit. So fit-bits. A model of an aptimer in wire , curled up to a certain extent . Its arranged into a 3D shape . It will usually make the same 3D shape every time . So if you have 1 specific piece of DNA and you leave it to its own devices it will usually fold up the same way every time. Aptimers bind proteins , they don't bind DNA. The lock and key mechanism like traditional medicine, par tof the aptimer wiull fit into a protein and then will block it from binding with something else. A graphical molecular view and a pocket inside a protein can accept the aptimer. The aptimer has some just visible lines that correspont to the strands of the helix. They can either fit inside or around something, depending on the size. Why are these so brilliant at binding. Its due to the way they are made. Finding what fits precisely into a pocket in a protein can be quite difficult screening 1000 different potential medicines to see if they fit. The beauty of using DNA to make the drugs is that instead of screening 1000 compounds . May not be one of that 1000, that why only 1 in 10 of pharmaceutical projects go anywhere. If you do it with SELEX termed so because it sounds like selection. You start with a library of DNA , say 10^9 , a billion sequences. You throw them in a flask with a target. Usualy you have the target immobilised so it is stuck to a surface . You throw your library of nucleotides over it and the binding ones will get stuck on the surface. Wash away the rest . Perhaps 900 million different ones have been removed as they don't bind at all. The ones remaining maybe 100,000 strands of DNA but you can't detect that. So you use PCR again and get back again to a billion sequences but this time not a billion different ones but 100,000 different ones. You add this enriched library back to your target and give it slightly harsher conditions. This time the ones that bind a little bit better , than before, removing the so-so binding ones . Amplify the ones that bind well and keep doing this about 10 times and then from the start of a billion sequences you might have 500 and you can then start to actually find out what those sequences were. You make your DNA library via DNA synthesizers . You can set them to random. You stipulate you wand this at one end , a random section in the middle , and then this at the other end. How doid my random section end up looking . So far this has produced one drug that has made it to market and again we've been doing it for 10 years. Q: That's more for diagnostics? Works very well as your target can be anything at all . Could be a protein in the body, or it could be Cocain . You could make an aptimer that could detect for cocain at airport swabbings of suitcase. Could be used for testing for heavy metals in drinking water . Or even whole cells , so for testing for such as E-Coli in drinking water. Its not massively used in disease diagnostics . The chemists and biochemists know they exist , but no doctors know they exist , it would seem. Or we've not been good enough at explaining them. Q: A long time ago , my first job . I ran a screening program for a pharmaceutical company. The process was a team of chemists producing organic compounds almost at random. The sceen would take a week. If something was promising it would take 3 or 4 months. Perhaps 1 in 3 or 400 was interesting . Go back to the chemists and make every variant you can of those and then test again. It was years and years. This process looks a lot faster. I was part of a team and I made 100 compounds in a year . I have used a similar process to this aptimers and in 4 months I was half way through the selection process . Its not every selection that works . Once the selection is done you still have some work to do, making something that will be stable in the body. But you could cut the process down to a year for the fisrst time , and 3 months in the all automated big labs. Another aspect of aptimers. Drugs that are supposed to prevent you having blood clots. Usually anticoagulants , preventing your blood from coagulating. then if you get a bleeding ulcer, the fact that your blood cannot coagulate , becomes a problem . In an accident or for surgery you need your blood to coagulate. so most of these anticoagulants have an antidote as well. Something you add that quickly neutralises them in your system. If you have an aptimer and you've not knotted it too well , if you add the strand that fits it , zips it up and in theory untangles it . Something that does not prevent your blood from coagulating. So instead of designing your drug and then more time designing the antidote, and aptimer drug would come with an antidote already. The same with diagnostics as its easy to test whether it works , because you know exactly how to make it stop working. DNA isn't just your genetic material , its amolecule that has amazing properties that you can use in the lab for something completely different . You can use it to mimic the body's processes but it can be an excellent tool for detecting disease. End of talk Q: Which company makes the drug you mentioned? The aptimer one I think was by Izaac ? , a lot so far have been made by small companies that made only a particular one. I think some have been bought up by some of the bigger companies. I think Pfizer has one and Roche has one in the pipeline. PCR? Polimerase Chain reaction. Polymerise means make many small units into one big unit. You have a double stranded bit of DNA that you want to copy. The first thing you do is heat it up which means that it fallls apart into 2 strands. Add a polymerase and a primer which is a little bit of DNA that tells the polymerase where to start. You add lots of building blocks , mix together , and the polymerase will make the complement to your original sequence of one strand and the complement of the othe rstrand. Now you have 4 bits of DNA , 2 identical pairs. You heat those ones up and they split apart and then 4 single strands add the polymerase mix and you end up with 8 strands. Thats why it can amplify so quickly because each step gives twice as much as the previous step. Q: So the polymerase is not concatenating, not joining them all together into a long chain as in conventional polymerising? No its copying single bases . It probably sounds more complicated than what it is than what it is in practise. You have a little tube, add polymerase , add template which is what you want copied, add 2 primers and a loyt of each ACG & T . You put it in a machine and tell it heat it up to separate, cool it down for the primer to attach, heat up a little bit for the enzyme to have the best possible conditions , leave for about a minute and repeat the same process. After the initial mixing all you then need is regulation of the temperature cycling which runs by itself. So you might do 30 cycles while you go out and have your lunch , say started with a 1000 copies and after lunch you have 1000 times 2 to the power 30. A lot. Q: Isn't that what causes problems in some of these forensic cases where they try to identify people by DNA and if they get any contamination then the contamination is amplified also. Exactly . You use PCR every time for forensic analysis of DNA . For some things its not a problem say a used condom or a large pool of blood , and so a lot of genetic material. So unless the person doing the testing is inept , in those circumstances it would be quite possible to tell which was the contaminant and which was the original. But if you were dealing with say someone who just touched my computer , left his DNA on that computer , or just one drop of blood that is slightly degraded then yes contamination becomes a problem. Contaminants can amplified, not perhaps as well as what you are looking for . If you have 1000x2^ 30 and 10 x 2^30 you can see the difference but if you start with 10 original and 10 contaminant then yes thats eaxactly the problem. The other problem is that yes DNA is unique, what they identify in forensic testing. But its more like 1 in a million will have the same profile that you are looking for but in the UK there is 60 million, 60 other people in the UK have the same sequence as you. So you need other evidence, you can't rely on DNA only . Its why we get verty displeased in the lab if someone does not wear gloves in the PCR room because they are shedding DNA at all times. Q: How many syndromes and diseases would you say have a genertic component to them? In a sense I'd say they all have a genetic component. Because everything we are and everything we do is at least in some small part can be taken back to your DNA . A lot of them , perhaps more than was previously thought, would have a 1000 different genes that have some kind of influence . If anyone has heard the term Junk-DNA as in that only a small part of your whole DNA that actually codes for proteins. I recommend this book "50 Genetics Ideas you really need to know" - Mark Henderson (2 copies in Soton City libraries), there is stuff in there I didn't know . They were saying that the genes that code for proteinsd are a bit like the verbs . The verbs are important to say what your doing but the nouns , the grammar and linguistics generally , and all the other words have a large effect. A lot of what was thought to encode junk DNA , and not have any influence, for instance that SIRNA where something binds the target and the target then gets cleaved , the body already does that , quite often that involves bits of what was called the junk_DNA , that makes these little bits of RNA that can then stop sa process from hapening. So I say all diseases have asome genetic component but whether you can get at that component . Q: Also the inverse of that , what proportion of people are not a carrier of a syndrome or disease or not go down with a syndrome or disease?. nothing recognisable whatsoever in the way of a medical condition , however deep you go.? I've no idea but I suspect it is very few, who didn't have something. The other thing is that we're finding out about the nature/nurture argument. We can even see that on people's genes , the field known as epigenetics. I've only just started working in the area of epigenetics . Epigenetics is changes that don't affect the sequence of your genes, not a mutation , not a gene but added structure to the genes , that affects for instance how it is rolled up and which parts of it are accessible. It might also that even if part of the gene is accessible epigenetic markers can go in and make it change its structure enough so for instance a protein cannot bind , what is called silencing a gene. For instance in the last Science Club there is a mouse dependent on what diet a pregnant mouse gets , the offspring will have exactly the same genes but depending on the diet it'll get different epigenetic masrkers and that can mean that one type is yellow and one type is brown. Also one type is fat and the other type is not. Its exactly the same active genetic sequence in both types but has been modified differently. Q: That must mean the epigenetic markers are duplicated at the time of production of the gametes as well then, not jus tthe DNA? Yes its not just the DNA. For quite a long time I don't think people thought that these could also be reproduced when a cell divided , but they are. During the second world war there was during one year in the Netherlands when there was a very low supply of food , they called it the Hunger Winter and you can see the effects of that via epigenetic markers, down to grandchildren, now. We don't know if it will contine . It turns out theese are heritable although not in your genetic sequence. Q: I suppose it could hinge on what you medicalise what could be the normal range of conditions anyway.? Its a bit like the piece I was reading in the Guardian today about a gene for breast cancer and it turns out that even if you have this gene that predisposes you to cancer it does not mean you get it , but a higher than normal risk. Depending on what it is your doctor will be able to tell you how much your increased risk is but it is never deterministic , never that you will get it. But just like smoking , and the quote "my granny smoked and she lived to 102 and was full healthy" , wheras someone else will smoke and get lung cancer at the age of 30. THat might be a combination of an epigenetic marker and environmental factor like smoking. Epigenetic markers will depend on your environment in whether they will have an effect or not. Q: Have you got involved with any industrial applications, say computers? Not personally . there is a lot of interest in whether DNA like structures can be used for computer memories . I've no idea on its viability but it is definitely information storage. Because it has this well defined Watson-Crick pairing , you can also use that to make extraordinary structures. If you take long pieces of DNA and add splints that will make it bend in a specific way , like a printer forming lines, forms into structures that are DNA "smiley faces" , this does have applications in computing making small devices like switches say. there are DNA walkers , bits of DNA molecule , I've seen where someone has made a triangle like form of DNA and then a road which is a complement of each of the 3 sides of the triangle and then be blocking off one side of the triangle you can make it tip onto the next bit of road . If you play around with how well they are stuck together , you make sure the one at the end of the road has the highest attraction , then it will walk along continuously. Don't stop funding our playtime. It is like Lego in that you have the building blocks and can put them doown in almost any way that you wish. Call it nonotechnology and you will get loads of money. Thats always been a good buzz-word for grand applications. Considering delivery , at least down the oral route and being digested. Would it still work if say you changed a sugar slightly to a form that is not so easily digested? That's what I did my PhD on, coincidently . Adding 4 atoms in total makes it 400 times more difficult to digest. Add enough of them and you can block digestion. It also makes it bind better. Its not been applied to many drugs as its not easy to make and most pharmaceuticals in addition to having to work, they must be easy to make. There is a lot of work in changing sugar structure. Also there is only so much manipulations you can make before it won't make a helix structure any more. So its a balance between having it do what you want it to do . Most of what I was doing was trying to get it to aptimers , but in order to do that you need the polymerase to recognise the building blocks that you make. You need it to distinguish between ATG and C , because polymerase is amazingly discriminating . They only make about 1 error in 10,000 , that alsop means that if you change something , even slightly, then most of the time polymerase will just reject it. You won't be able to build it in properly or won't be able to contine past it. So a lot of the work in this area is to make it recognisable to the body , but different enough that it doesn't get degraded so quickly. Q: Do the copies that polymerase make , have the same (complements? ) in? What I did never made it to the aptimer stage, because you have 2 parts more . The optimum with SIRNA or optimers is that you'd make them in a lab , in the body they would not work, the body could not amplify them . For one thing that could potentially be dangerous but also the polymerase that we use for PCR have been developed from organisms that live around deep sea vents , organisms that are used to living at about 100 degree C. It needs to be these ones because as you heat a reaction you speed it up and so to make it work on a reasonable timescale and also the PCR heating to separate stage and that often means you need to go up to about 100 degrees . So you need a polymerase that can stand that and any polymerase in the human body does not like more than 37 degrees. Like everything else in the human body, heat it up to 40 degrees and it tends not to work any more. So yes you would be able to add modifications but only in the lab. 7/00/51 2/19/55/48 to be continued


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