: / / dx. doi. org / 10. 1093 / nar / gkq1061 ] webcite nene v, wortman jr, lawson d, haas b, kodira c, tu zj, loftus b, xi z, megy k, grabherr m, et al. : genome sequence of aedes aegypti, a major arbovirus vector. [ http : / / dx. doi. org / 10. 1126 / science. 1138878 ] webcite enright aj, dongen sv, ouzounisw ca : an efficient algorithm for large - scale detection of protein families. [ http : / / nar. oxfordjournals. org / content / 30 / 7 / 1575. abstract ] webcite guindon s, gascuel o : a simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. [ http : / / www. jstor. org / sici? sici = 1063 - 5157 ( 200310 ) 52 % 3a5 % 3 c696 % 3aasfaaa % 3e2. 0. co % 3b2 - j ] webcite j mol biol 1990, 215 ( 3 ) : 403 - 410. pubmed abstract hotopp jcd, clark me, oliveira dcsg, foster jm, fischer p, torres mcm, giebel jd, kumar n, ishmael n, wang s, ingram j, nene rv, shepard j, tomkins j, richards s, spiro dj, ghedin e, slatko be, tettelin h, werren jh : widespread lateral gene transfer from intracellular bacteria to multicellular eukaryotes. [ http : / / dx. doi. org / 10. 1126 / science. 1142490 ] webcite capy p, gasperi g, biemont c, bazin c : stress and transposable elements : co - evolution or useful parasites? [ http : / / www. nature. com / hdy / journal / v85 / n2 / abs / 6887510a. html ] webcite heredity 2000, 85 ( pt 2 ) : 101 - 106. pubmed abstract swingley wd, blankenship re, raymond j : integrating markov clustering and molecular phylogenetics to reconstruct the cyanobacterial


the hydraulic system in the 787 no - bleed architecture is similar to the one in the traditional architecture. there are three independent systems — left, center, and right — that collectively support primary flight control actuators, landing gear actuation, nose gear steering, thrust reversers, and leading / trailing edge flaps. the primary power source for the left and right systems are engine - driven pumps mounted on the engine gearbox. in addition, the left and right systems are each powered by an electric - motor - driven hydraulic pump for peak demands and for ground operations. the key difference between the traditional and 787 hydraulic system is the power source for the center system. in the traditional architecture, the center system is powered by two large air - turbine - driven hydraulic pumps, which operate at approximately 50 gallons per minute ( gpm ) at 3, 000 pounds per square inch ( psi ) to meet peak hydraulic demands for landing gear actuation, high lift actuation and primary flight control during takeoff and landing. during the remainder of the flight, two small ( approximately 6 gpm ) electric - driven hydraulic pumps power the center system. in the 787 no - bleed architecture, the center hydraulic system is powered by two large ( approximately 30 gpm at 5, 000 psi ) electric - motor - driven hydraulic pumps. one of the pumps runs throughout the entire flight and the other pump runs only during takeoff and landing. the higher pressure of the 787 ' s hydraulic system enables the airplane to use smaller hydraulic components, saving both space and weight. the 787 uses an electrical system that is a hybrid voltage system consisting of the following voltage types : 235 volts alternating current ( vac ), 115 vac, 28 volts direct current ( vdc ), and ±270 vdc. the 115 vac and 28 vdc voltage types are traditional, while the 235 vac and the ±270 vdc voltage types are the consequence of the no - bleed electrical architecture that results in a greatly expanded electrical system generating twice as much electricity as previous boeing airplane models. the system includes six generators — two per engine and two per apu — operating at 235 vac for reduced generator feeder weight. the system also includes ground power receptacles for airplane servicing on the ground without the use of the apu. the generators are directly connected to the engine gearboxes and therefore operate at a variable frequency ( 360 to 800 hertz ) proportional to the engine speed. this type of generator is the simplest and the most efficient generation method because it does


the apu. the generators are directly connected to the engine gearboxes and therefore operate at a variable frequency ( 360 to 800 hertz ) proportional to the engine speed. this type of generator is the simplest and the most efficient generation method because it does not include the complex constant speed drive, which is the key component of an integrated drive generator ( idg ). as a result, the generators are expected to be more reliable, require less maintenance, and have lower spare costs than the traditional idgs. the electrical system features two electrical / electronics ( e / e ) bays, one forward and one aft, as well as a number of remote power distribution units ( rpdu ) for supporting airplane electrical equipment. the system saves weight by reducing the size of power feeders. a limited number of 235 vac electrical equipment is supplied from the aft e / e bay, while the majority of airplane electrical equipment, being either 115 vac or 28 vdc, are supported by the forward e / e bay and rpdus as shown schematically in figure 3. the rpdus are largely based on solid - state power controllers ( sspc ) instead of the traditional thermal circuit breakers and relays. the ±270 vdc system is supplied by four auto - transformer - rectifier units that convert 235 vac power to ±270 vdc. the ±270 vdc system supports a handful of large - rated adjustable speed motors required for the no - bleed architecture. these include cabin pressurization compressor motors, ram air fan motors, the nitrogen - generation - system compressor used for fuel - tank inerting, and large hydraulic pump motors. the system, as shown in figure 3, features two forward 115 vac external power receptacles to service the airplane on the ground without the apu and two aft 115 vac external power receptacles for maintenance activities that require running the large - rated adjustable speed motors.


survival of the people logic puzzles require you to think. you will have to be logical in your reasoning. there is an island with 10 inhabitants. one day a monster comes and says that he intends to eat every one of them but will give them a chance to survive in the following way : in the morning, the monster will line up all the people - single file so that the last person sees the remaining 9, the next person sees the remaining 8, and so on until the first person that obviously sees no one in front of himself. the monster will then place black or white hats on their heads randomly ( they can be all white, all black or any combination thereof ). the monster will offer each person starting with the last one ( who sees everyone else ' s hats ) to guess the color of his / her own hat. the answer can only be one word : " white " or " black ". the monster will eat him on the spot if he guessed wrong, and will leave him alive if he guessed right. all the remaining people will hear both the guess and the outcome of the guess. the monster will then go on to the next to last person ( who only sees 8 people ), and so on until the end. the monster gives them the whole night to think. devise the optimal strategy that these poor natives could use to maximize their survival rate. 1 ) all the 10 people can easily understand your strategy, and will execute it with perfect precision. 2 ) if the monster suspects that any of the people are giving away information to any of the remaining team members by intonation of words when answering, or any other signs, or by touch, he will eat everyone. 3 ) the only allowed response is a short, unemotional " white " or " black ". 4 ) having said that, i will add that you can put any value you like into each of these words. for example, " white " can mean " my mother did my laundry " and " black " can mean the guy in front of me is wearing a black hat. hint1 ) first hint is an example. here is a simple strategy that will guarantee safety to 50 %. guy # 10 ( when he guesses ) says the color of the hat on guy # 9. thus # 10 may die or may luck out, but # 9 will save himself since he will know his hat color. thus # 8 helps # 7, # 6 helps number # 5, and so on. you thus save numbers 9, 7, 5, 3


may die or may luck out, but # 9 will save himself since he will know his hat color. thus # 8 helps # 7, # 6 helps number # 5, and so on. you thus save numbers 9, 7, 5, 3, and 1, or half the people. but you can do a lot better than that. 2 ) the best strategy will save a minimum of 90 % of the people. here it is : the first guy to guess ( guy # 10 ) will be the only one to assume the following value for the words " white " and " black " : the answer " black " will mean that there are an odd number of black hats that he sees. the answer " white " will mean that there are an odd number of white hats that he sees. this way one by one all the other 9 people will know the color of their hats. let us say that guy # 10 ( first to speak, and sees the hats of the remaining 9 ) says " white ". that should mean to everybody else that he sees an odd number of white hats. at this time guy # 9 will either be wearing a white or a black hat. if he is wearing a white hat he will only see an even number of white hats, and since guy # 10 said that there is and odd number of white hats, guy # 9 will know that he is wearing white and will say it. but if guy # 9 is wearing a black hat, he will see an odd number of white hats ( just like # 10 did ), and thus will know that he is wearing a black hat and will say it. no matter what # 9 answers, guy # 8 ( who heard guy # 10 and guy # 9 ) can now easily incorporate the color of hat on guy # 9 into the original answer of guy # 10. this will allow # 8 to know if he should see an odd or even number of white hats in front of him to determine his own hat color. the same thing repeats with # 7 - 1. and they all get it right except of course # 10, though he may get lucky. jan 18, 2003 jan 21, 2003 | wow, this one makes a lot of sense logically. great teaser. | jan 25, 2003 | it makes sense but i would never have came to that answer | jan 29, 2003 | what ' s wrong with simply saying the color of the hat of the person infront of you? same survival percentage. | jan 30, 2003 | in reply to "


sense but i would never have came to that answer | jan 29, 2003 | what ' s wrong with simply saying the color of the hat of the person infront of you? same survival percentage. | jan 30, 2003 | in reply to " asbestos ' " comment. you would only save 50 % that way. if you say the color of the person in front of you ( lets say black ), he / she still has to say black not to get eaten ( regardless of what the color in front of them is ). so therefore the 3rd person in line will not know their own color since the person before them saved themselves and didn ' t necessarily speak the color of the next person. | feb 06, 2003 | nice teaser... but situation might mess up after the number 9 guess says his answer. and plus the monster might have put them on not white black white black... etc. | feb 07, 2003 | golfer, there ' s nothing wrong with the logic in this teaser. it will work no matter what arrangement of hats the monster uses. also, assumption # 1 states that person number 9 will not mess up. i must say that this is a terrific logic teaser in my opinion. | feb 11, 2003 | this was a great riddle with great logic. the best i could do was save a minimum of five depending on the arrangement of hats. | feb 15, 2003 | i think it was a bit long personally but it does all make sence so great teaser | feb 15, 2003 | the logic works well. actually, even if person 9 makes the wrong answer, the monster will eat that person, which would be a pretty strong indicator that they made the wrong decision. this could also be accounted for. the only person who need be correct is 10, the rest can be saved by their own logic. | feb 15, 2003 | wow, that was an exellent teaser! | feb 15, 2003 | another way to win is if the 10th guy tells everyone that " white " means your hat is the same color as the guy in front of you and " black " means your hat is a different color from the guy in front of you. therefore, the only two who have to rely on luck are the 1st and the 10th | feb 16, 2003 | this will not work pookie21. you need to say the colour of your hat in order not to get eaten. | feb 17, 2003 | awesome logic teaser, one of the best i have seen. i could only


16, 2003 | this will not work pookie21. you need to say the colour of your hat in order not to get eaten. | feb 17, 2003 | awesome logic teaser, one of the best i have seen. i could only think of the 50 % solution, so i was going to stand and fight to the death. maybe dig a large spike filled covered hole behind the 10th person as a trap for the monster. but that is not really solving the teaser, it is a captain kirk type of solution. 8 ^ ) | feb 27, 2003 | this is by far the best teaser i ' ve read here. course, i just got here and am going thru the ' most popular list '. | btw, i came up with the even guys sacrifice by saying the color of the guy in front of thems color, like many of you. which would result in at least 50 % survival ( odds - wise more like 70 or 80 % ). think about it... however tyhe solution is brilliant! 90 % guaranteed, with 100 % possible. really cool puzzler! feb 28, 2003 | that ' s going straight to my favourites list... totally a great teaser. it was really fun n. n ; and really hard as well oo ;... i came up with some weird thing that was just a guess... nice brain btw. | apr 11, 2003 | boy, would i not wanna be the last person in line... | may 06, 2003 | wouldn ' t mind being the last guy. being the first guy is a problem. brilliant teaser! | jun 17, 2003 | my solution was that the last person would say black or white depending on how many times the colour changed in front of him. black for even no. of times and white for odd no. of times. from this each person could find out his own colour by seeing the no. of colour changes and deciding whether he is the same colour as the one in front. the given soln. is much simpler, though. | jul 02, 2003 | ya, i got this one. if you know anything about computers, this is the same concept as parity. the way i did it is that white means there are an even number of white hats, while black means odd. take 0 to mean even. great riddle | nov 15, 2003 | great logic! i loved the teaser. | jan 05, 2004 | a 3. 0 / 3. 0 teaser.


an even number of white hats, while black means odd. take 0 to mean even. great riddle | nov 15, 2003 | great logic! i loved the teaser. | jan 05, 2004 | a 3. 0 / 3. 0 teaser. one of the best | jan 09, 2004 | thats a hard 1 | feb 01, 2004 | great teaser! | oct 31, 2004 | if the first guy yells out the color of the hat of the guy in front, he ' s got a 50 / 50 shot at guessing right for his own. from then on, everyone knows the color of their own hat. | nov 01, 2004 | oops - that won ' t work. | apr 10, 2005 | it ' s too long! | may 22, 2005 | that was a hard one for me. | may 23, 2005 i think i ' ve done a similar one a long time ago, but it involved 3 people, pink & purple hats, and a wall separating 2 people from the other person... jun 03, 2005 | the whole thing about and odd number of black and white hats deosn ' t make sense. if there are ten hats, and an odd number ( let ' s say 7 ) of white hats, then there are an odd number of black hats too ( 3 in this case ). what does the last guy yell if there are an even number of each? ( let ' s say 4 white and 6 black ). if there are an odd number, then it shouldn ' t matter what color he yells. | jun 04, 2005 | this is in response to ragsdaleam : | if you read the solution carefully, it doesn ' t suggest that you should communicate the color that has an odd number of hats, it suggests that you should communicate weather one specific color ( agreed upon in advance ) will be present in an odd amount or an even amount. in other words if we agreed that " white " means that there is an odd number of blacks, and " black " means that there is an even number of blacks, we will always be able to relate weather there is an even or odd number of black hats ( independent of how many white hats there are ). jun 04, 2005 | or you can have it done as it states in the solution, where all you are looking for is an indication of weather or not one of the colors is odd or even ( independent of how many hats of the other color there are ). to figure out what you have you just


as it states in the solution, where all you are looking for is an indication of weather or not one of the colors is odd or even ( independent of how many hats of the other color there are ). to figure out what you have you just gotta count. so in your example of 7 black and 3 white. if i know that there is an odd number of whites and i am the 9th guy. i can count what is ahead of me. i will either see 3 whites or 2 in front of me and if i see 2 then i have the third one. same logic for all consecutive players. | jun 06, 2005 | directly form your explanation of the answer : | " the answer " black " will mean that there are an odd number of black hats that he sees. the answer " white " will mean that there are an odd number of white hats that he sees. " so what would he say if there are an even number of both? jun 06, 2005 | you know, funny enough, you are right. i am surpirsed no - one noticed. the solution still works just needs to be rephrased : | the answer " black " will mean that there are an odd number of black hats that he sees. the answer " white " will mean that there are an even number of black hats that he sees ( zero black hats should be treated as an even number ). aug 10, 2005 | ragsdaleam, your logic is a little off. the tenth person can only see 9 hats, so theres no way that he can see both an odd number of black and an odd number of white hats. | mar 14, 2006 | yes, ever since ragsdaleam ' s comment on the fact that if there are 8 black, then there are 2 whites, everybody has been wrong. number 10 ' s hat color has nothing to do with the puzzle, because he can only see 9 hats. if he sees 3 black hats, then he will see 6 white hats, so he will say black, and therefore save his fellow native ' s, and maybe even his own life ( whether his hat happens to be black or not, he has a 50 / 50 chance ). | apr 20, 2006 | first of all i want to say that this was an excellent riddle. the answer given makes sense and is one solution to the problem, but i believe me and my colleagues have found an alternate solution which results in the same survival rate. check this scenario out : overnight we agree that when the monster


was an excellent riddle. the answer given makes sense and is one solution to the problem, but i believe me and my colleagues have found an alternate solution which results in the same survival rate. check this scenario out : overnight we agree that when the monster asks the color of the hat of native # 10, he will call out the color of the person in front of him. from native # 9 onward we will use a code system, if you answer " quickly ", that will mean that the color of the person in front of you is white, if you give a " delayed " answer, that will mean that the color of the person in front of you is black. in this way you can save a minimum of 90 % of the natives with a possible 100 % if the # 10 guy gets lucky. i think this is a less complex answer and it is simpler to understand. | apr 21, 2006 | for paragon83. your answer would be great actually if not for the " assumption " section of the teaser. points ( 2 ) and ( 3 ) have been clarified for that exact purpose. if the monstr suspects any such foul play the risk is that everyone will get eaten. | nov 15, 2007 | hehehe... i don ' t think that the poor natives will understand because they not even know what is odd and what is even. as you said earlier the solution must be simple so that the natives can understand easily. if some of them make a mistake....... the monster will be happy. | mar 10, 2010 | does the ansewer work if the monster uses 5 black and 5 white hats. it doesnt say that in the question | mar 10, 2010 | doesnt * the ansewer only work if he uses 5 of each? | jan 29, 2011 | again you can only assume that the monster doesn ' t pick that combination of hats | jan 22, 2012 | i have a solution that is slightly more optimal than the given one. it involves an arbitrarily high level of precision for the villagers, but given assumption 1 such strategies are valid. the strategy is as follows : | black hats represent 0. white hats represent 1. the last villager sees 9 hats, and thus 9 digits that represent a unique number in binary form. the 10th villager then waits exactly this many ( arbitrarily small ) time units from the time he is prompted to guess his color before giving an answer. all other villagers then have perfect information about


that represent a unique number in binary form. the 10th villager then waits exactly this many ( arbitrarily small ) time units from the time he is prompted to guess his color before giving an answer. all other villagers then have perfect information about every villager ' s hat from 1 to 9. when it is each villager ' s turn to ' guess, ' they each wait the exact amount of time before giving their answer as did the first villager, so there is no distinction between answers and the monster has no reason to suspect foul play. the reason this solution is slightly more optimal is because it results in a higher probability of the 10th villager surviving. in the given solution, the 10th villager ' s answer is completely determined by the monster ' s configuration of hats, and cannot be changed. in my solution, the 10th villager can give the guess that is statistically favored ( or just a random guess ), thus ensuring a 95 % survival rate in all cases. apr 23, 2012 | this is definitely one of my all time favorites! i worked on this for days and ultimately came up with this overly complicated equation, that as it turns out simply meant that if there were an odd number of white hats # 10 would say white, and if there were an even number of white hats, he ' d say black. i didn ' t even realize that that was the answer i ended up with until i looked at the solution and read back over my answer. i ' m either dumb for a smart guy or smart for a dumb guy. or possibly just lucky for a dumb guy. | as for vecht ' s answer, what a creative solution! i tried to think of a way to make binary code work for me, but i just couldn ' t make it fit. although i think the given answer is a whole lot simpler. and # 10 ' s chances are 50 / 50 no matter what. no amount of statistical analysis will help, because the teaser states that the monster places the hats at random. no matter which color # 10 says, whether he says it because it imparts meaning to the others, or because he was guessing, he will still have a 1 out of 2 chance of getting it right as long as the hat placement was random. but anyway, kudos to sakirski for a killer logic puzzle! feb 22, 2013 | sakiriski, you are now one of my fave teaser - posters. i got the same solution as the answer ( yay! ) but i


raphael a. zoeller, ph. d. associate professor of physiology and biophysics b. s. university of maine ph. d. texas a & m university phone : ( 617 ) 638 - 4010 • fax : ( 617 ) 638 - 4041 cell and membrane biology lipids are not only structural units of membranes. they also participate in important cellular functions, serving as second messengers, hormones, pheromones and membrane anchors for proteins. although several “ active ” lipid species have been identified, there are many others that remain undiscovered. to identify functional roles for lipids, we develop mutant animal cell lines that are deficient in the biosynthesis of specific lipid species. using these mutants, we can determine what cellular processes are affected by the loss of the lipid, establishing a role for the lipid in that process. the mutants can also serve as tools for the isolation of the genes involved in the biosynthesis of the lipid. most importantly, the study of these mutants leads to new biochemistry, not achievable through conventional approaches. plasmalogens : endogenous antioxidants. this “ subclass ” of phospholipids makes up approximately 18 % of the phospholipids in humans and they are enriched in certain cell types or tissues including macrophages, neutrophils, brain and heart. although their presence in mammalian tissue is well characterized, their role in cell function remained unclear. we developed a selection protocol to isolate mutant strains with defects in plasmalogen biosynthesis. using these mutant strains, we have identified two phenotypes that are tied to the loss of plasmalogens. first, the plasmalogen - deficient cells are hypersensitive to reactive oxygen species ( ros ) and this is reversed with the restoration of plasmalogens. this has lead to the suggestion that plasmalogens function as endogenous antioxidants. this may help to explain the rapid development of cataracts in the plasmalogen - deficient patients. the second phenotype associated with plasmalogen loss is a decrease in cholesterol transport. based on our findings using the mutants, we examined the possibility that plasmalogen levels could be increased in normal cells and if this would protect them under conditions in which ros are formed. we found that supplementation of human endothelial cells with a plasmalogen biosynthetic precursor, hexa


that plasmalogen levels could be increased in normal cells and if this would protect them under conditions in which ros are formed. we found that supplementation of human endothelial cells with a plasmalogen biosynthetic precursor, hexadecylglycerol ( hg ) elevated plasmalogen levels 2 - fold and protected them from damage due to oxidants. importantly, this also protected these cells during chronic hypoxia, a physiologically relevant condition ( figure 1 ). this opens up the possibility of treatment of patients under conditions of chronic hypoxia such as pulmonary dysfunction. we are now attempting to determine the exact mechanism by which hg rescues these cells. mutants in global glycerolipid synthesis the control of glycerolipid biosynthesis, including triacylglycerols is an area of intense interest, particularly with concerns about obesity and diabetes. glycolysis is coordinated with and controls lipogenesis through mechanisms that are still poorly understood. we have developed a procedure for selecting mutants that are deficient in general glycerolipid biosynthesis in an effort to identify factors that are important for lipogenesis in animal cells. we have recently identified one mutant, named grod1, that is defective in the synthesis of phosphatidylethanolamine ( pe ), phosphatidylcholine ( pc ) ( figure 2 ). these cells are also defective in the synthesis of triacylglycerols. this phenotype is due to a severe reduction in the activity of phosphatidate phosphohydrolase 1 ( pap1 ). expression cloning of the gene responsible for this lesion has revealed a relationship between glycolysis and lipogenesis that was previously unknown. we are currently attempting to explain the mechanics of this relationship using the grod1 cells. we are also screening for additional, novel mutants with additional lesions in glycerolipid biosynthesis to identify additional factors regulating this process. nakahara k, ohkuni a, kitamura t, abe k, naganuma t, ohno y, zoeller ra and kihara a ( 2012 ) the sjogren - larsson syndrome gene encodes a hexadecenal dehydrogenase of the sphingosine 1 - phosphate degradation pathway. molecular cell 46 : 461 - 71. krawczyk sa, haller jf, fe


larsson syndrome gene encodes a hexadecenal dehydrogenase of the sphingosine 1 - phosphate degradation pathway. molecular cell 46 : 461 - 71. krawczyk sa, haller jf, ferrante t, zoeller ra, corkey be. ( 2012 ) reactive oxygen species facilitate translocation of hormone sensitive lipase to the lipid droplet during lipolysis in human differentiated adipocytes. plos one, 7 : e349042012. haller jf, krawczyk sa, gostilovitch l, corkey be and zoeller ra ( 2011 ) glucose - 6 - phosphate isomerase deficiency results in mtor activation, failed translocation of lipin 1α to the nucleus and hypersensitivity to glucose : implications for the inherited glycolytic disease. biochim biophys acta. 1812 : 1393 - 402. anbukumar, d. s., shornick, l. p., albert, c. j., steward, m. m., zoeller, r. a., neumann, w. l., and ford, d. a. ( 2010 ) chlorinated lipid species in activated human neutrophils : lipid metabolites of 2 - chlorohexadecanal. j lipid res. 51 : 1085 - 1092. haller, j. f., smith, c., liu, d., zheng, h., tornheim, k., han, g., carman, g. m. and zoeller, r. a. ( 2010 ) isolation of novel animal cell lines defective in glycerolipid biosynthesis reveals mutations in glucose - 6 - phosphate isomerase. j. biol. chem. 285 : 866 - 877. gaposchkin, d. p., farber, h. w. and zoeller, r. a. ( 2008 ) on the importance of plasmalogen status in stimulated arachidonic acid release in the macrophage cell line raw 264. 7. biochim biophys acta. 1781 : 213 - 219. zheng h, duclos ri jr, smith cc, farber hw, zoeller ra. 2006. synthesis and biological properties of the fluorescent ether lipid precursor 1 - o - [ 9 ' - ( 1 ' ' - p


- 219. zheng h, duclos ri jr, smith cc, farber hw, zoeller ra. 2006. synthesis and biological properties of the fluorescent ether lipid precursor 1 - o - [ 9 ' - ( 1 ' ' - pyrenyl ) ] nonyl - sn - glycerol. j lipid res. 47 : 633 - 642. liu d, nagan n, just ww, rodemer c, thai tp, zoeller ra. 2005. role of dihydroxyacetonephosphate acyltransferase in the biosynthesis of plasmalogens and nonether glycerolipids. j lipid res. 46 : 727 - 735 zoeller ra, grazia tj, lacamera p, park j, gaposchkin dp, farber hw. 2002. increasing plasmalogen levels protects human endothelial cells during hypoxia. am j physiol heart circ physiol. 283 : h671 - 679. zoeller ra, lake ac, nagan n, gaposchkin dp, legner ma, lieberthal w. 1999. plasmalogens as endogenous antioxidants : somatic cell mutants reveal the importance of the vinyl ether. biochem j. 338 : 769 - 776. department of physiology and biophysics boston university school of medicine 700 albany street boston ma 02118 - 2526 fax : ( 617 ) 638 - 4041


— a gene on chromosome 2, called epas1, involved in red blood cell production and hemoglobin concentration in the blood. originally working separately, the authors of the study first put their findings together at a march 2009 meeting at the national evolutionary synthesis center in durham, nc. " some of us had been working on the whole of tibetan dna. others were looking at small groups of genes. when we shared our findings we suddenly realized that both sets of studies pointed to the same gene $ mdash ; epas1, " said robbins, who co - organized the meeting with beall. while all humans have the epas1 gene, tibetans carry a special version of the gene. over evolutionary time individuals who inherited this variant were better able to survive and passed it on to their children, until eventually it became more common in the population as a whole. " this is the first human gene locus for which there is hard evidence for genetic selection in tibetans, " said co - author peter robbins of oxford university. researchers are still trying to understand how tibetans get enough oxygen to their tissues despite low levels of oxygen in the air and bloodstream. until then, the genetic clues uncovered so far are unlikely to be the end of the story. " there are probably many more signals to be characterized and described, " said co - author gianpiero cavalleri of the royal college of surgeons in ireland. for those who live closer to sea level, the findings may one day help predict who is at greatest risk for altitude sickness. " once we find these versions, tests can be developed to tell if an individual is sensitive to low - oxygen, " said co - author changqing zeng of the beijing institute of genomics. " many patients, young and old, are affected by low oxygen levels in their blood — perhaps from lung disease, or heart problems. some cope much better than others, " said co - author hugh montgomery, of university college london. " studies like this are the start in helping us to understand why, and to develop new treatments. " the team ' s findings will be published online the week of june 7 in proceedings of the national academy of sciences.


03 - 13 - 2006, 01 : 30 am mammal extinct for 11 million years is... well.... not extinct washington ( ap ) - - it has the face of a rat and the tail of a skinny squirrel - - and scientists say this creature discovered living in central laos is pretty special : it ' s a species believed to have been extinct for 11 million years. the long - whiskered rodent made international headlines last spring when biologists declared they ' d discovered a new species, nicknamed the laotian rock rat. it turns out the little guy isn ' t new after all, but a rare kind of survivor : a member of a group until now known only from fossils. nor is it a rat. this species, called diatomyidae, looks more like small squirrels or tree shrews, said paleontologist mary dawson of pittsburgh ' s carnegie museum of natural history. dawson, with colleagues in france and china, report the creature ' s new identity in friday ' s edition of the journal science. the resemblance is " absolutely striking, " dawson said. as soon as her team spotted reports about the rodent ' s discovery, " we thought, ' my goodness, this is not a new family. we ' ve known it from the fossil record. " ' they set out to prove that through meticulous comparisons between the bones of today ' s specimens and fossils found in china and elsewhere in asia. to reappear after 11 million years is more exciting than if the rodent really had been a new species, said george schaller, a naturalist with the wildlife conservation society, which unveiled the creature ' s existence last year. indeed, such reappearances are so rare that paleontologists dub them " the lazarus effect. " another well - known example is the coelacanth, a primitive fish that existed before the dinosaurs and was thought to have gone extinct 65 million years ago, until one was caught in 1938 off the coast of southern africa. " it shows you it ' s well worth looking around in this world, still, to see what ' s out there, " schaller said. the nocturnal rodent lives in laotian forests largely unexplored by outsiders, because of the geographic remoteness and history of political turmoil. schaller called the area " an absolute wonderland, " because biologists who have ventured in have found unique animals, like a type of wild ox called the saola, barking deer, and never - before - seen bats


table of contents what is session initiation protocol? components of sip what is the cisco sip ip phone? cisco sip ip phone connections connecting to the network connecting to power using a headset the cisco sip ip phone with a catalyst switch this chapter contains the following information about the cisco sip ip phone : • what is session initiation protocol? • what is the cisco sip ip phone? • cisco sip ip phone connections • the cisco sip ip phone with a catalyst switch what is session initiation protocol? session initiation protocol ( sip ) is the internet engineering task force ' s ( ietf ' s ) standard for multimedia conferencing over ip. sip is an ascii - based, application - layer control protocol ( defined in rfc 2543 ) that can be used to establish, maintain, and terminate calls between two or more end points. like other voip protocols, sip is designed to address the functions of signaling and session management within a packet telephony network. signaling allows call information to be carried across network boundaries. session management provides the ability to control the attributes of an end - to - end call. sip provides the capabilities to : • determine the location of the target end point — sip supports address resolution, name mapping, and call redirection. • determine the media capabilities of the target end point — via session description protocol ( sdp ), sip determines the " lowest level " of common services between the end points. conferences are established using only the media capabilities that can be supported by all end points. • determine the availability of the target end point — if a call cannot be completed because the target end point is unavailable, sip determines whether the called party is already on the phone or did not answer in the allotted number of rings. it then returns a message indicating why the target end point was unavailable. • establish a session between the originating and target end point — if the call can be completed, sip establishes a session between the end points. sip also supports mid - call changes, such as the addition of another end point to the conference or the changing of a media characteristic or codec. • handle the transfer and termination of calls — sip supports the transfer of calls from one end point to another. during a call transfer, sip simply establishes a session between the transferee and a new end point ( specified by the transferring party ) and terminates the session between the transferee and the transferring party. at the end of a call, sip terminates the sessions between all parties. conferences can consist of two or more users and can be established using multicast


( specified by the transferring party ) and terminates the session between the transferee and the transferring party. at the end of a call, sip terminates the sessions between all parties. conferences can consist of two or more users and can be established using multicast or multiple unicast sessions. note the term conference means an established session ( or call ) between two or more end points. in this document, the terms conference and call are used interchangeably. components of sip sip is a peer - to - peer protocol. the peers in a session are called user agents ( uas ). a user agent can function in one of the following roles : • user agent client ( uac ) — a client application that initiates the sip request. • user agent server ( uas ) — a server application that contacts the user when a sip request is received and that returns a response on behalf of the user. typically, a sip end point is capable of functioning as both a uac and a uas, but functions only as one or the other per transaction. whether the endpoint functions as a uac or a uas depends on the ua that initiated the request. from an architecture standpoint, the physical components of a sip network can also be grouped into two categories : clients and servers. figure 1 - 1 illustrates the architecture of a sip network. note in addition, the sip servers can interact with other application services, such as lightweght directory access protocol ( ldap ) servers, a database application, or an extensible markup language ( xml ) application. these application services provide back - end services such as directory, authentication, and billing services. figure 1 - 1 sip architecture sip clients include : • phones — can act as either a uas or uac. softphones ( pcs that have phone capabilities installed ) and cisco sip ip phones can initiate sip requests and respond to requests. • gateways — provide call control. gateways provide many services, the most common being a translation function between sip conferencing endpoints and other terminal types. this function includes translation between transmission formats and between communications procedures. in addition, the gateway also translates between audio and video codecs and performs call setup and clearing on both the lan side and the switched - circuit network side. sip servers include : • proxy server — the proxy server is an intermediate device that receives sip requests from a client and then forwards the requests on the client ' s behalf. basically, proxy servers receive sip messages and forward them to the next sip server in the network


ip phone user to request forwarding service from the network ( via a third party tool that enables this feature to be configured ). when a call is placed to the user ' s phone, it is redirected to the appropriate forward destination by the sip proxy server. – call hold — allows the cisco sip ip phone user ( user a ) to place a call ( from user b ) on hold. when user a places user b on hold, the 2 - way rtp voice path between user a and user b is temporarily disconnected but the call session is still connected. when user a takes user b off hold, the 2 - way rtp voice path is reestablished. – call transfer — allows the cisco sip ip phone user ( user a ) to transfer a call from one user ( user b ) to another user ( user c ). user a places user b on hold and calls user c. if user c accepts the transfer, a session is established between user b and user c and the session between user a and user b is terminated. – three - way calling — allows a " bridged " 3 - way call. when a 3 - way call is established, the cisco sip ip phone through which the call is established acts as a bridge, mixing the audio media for the other parties. – do not disturb — allows the user to instruct the system to intercept incoming calls during specified periods of time when the user does not want to be disturbed. – multiple directory numbers — allows the cisco sip ip phone to have up to six directory numbers or lines. – call waiting — plays an audible tone to indicate that an incoming call is waiting. the user can then put the existing call on - hold and accept the other call. the user can alternate between the two calls. – direct number dialing — allows users to initiate or receive a call using a standard e. 164 number format in a local, national, or international format. – direct url dialing — provides the ability to place a call using an email address instead of a phone number. – caller id blocking — allows the user to instruct the system to block their phone number or email address from phones that have caller identification capabilities. – anonymous call blocking — allows the user to instruct the system to block any calls for which the identification is blocked. • user - defined proxy routing the " route " attribute of the template tag in the dial plan template file can be used to indicate which proxy ( default, emergency, fqdn ) that the call should be initially routed


_ " ; as in " _ protocol. _ transport. ". the addition of the underscore reduces the risk of the same name being used for unrelated purposes. also in compliance with rfc 2782 and the draft - ietf - sip - srv - 01 spec. is that the system can remember multiple ip addresses and use them properly. in the draft - ietf - sip - srv - 01 spec, it is assumed that all proxies returned for the srv record are equivalent such that the phone can register with any of the proxies and initiate a call using any other proxy. vad can be enabled or disabled with enable _ vad parameter. value 0 for disable, and value 1 for enable. see enable _ vad parameter in modifying the default sip configuration file in " managing cisco sip ip phones ". three - way conferencing supports one phone conferencing with two other phones by providing mixing on the initiating phone. to set up a 3 - way conference call, see documentation on making conference calls in " getting started with the cisco ip phone 7960 ". see release note for limitations. if the invite message contains an alert - info header, distinctive ringing is invoked, format of the header is " alert - info : x ". " x " can be any number. this header is only received by the phone and is not generated by the phone. distinctive ringing is supported when the phone is idle or during a call. in the idle mode, the phone rings with a different cadence. the selected ringing type plays twice with a short pause in between. in call - waiting mode, two short beeps are generated instead of one long beep. note for information on how to use the standard telephony features and url dialing, refer to the getting started cisco ip phone 7960 and quick reference cisco ip phone 7960 documents. the cisco sip ip phone supports the following standard protocols : • domain name system ( dns ) dns is used in the internet for translating names of network nodes into addresses. sip uses dns to resolve the host names of end points to ip addresses. • dynamic host control protocol ( dhcp ) dhcp is used to dynamically allocate and assign ip addresses. dhcp allows you to move network devices from one subnet to another without administrative attention. if using dhcp, you can connect cisco sip ip phones to the network and become operational without having to manually assign an ip address and additional network parameters. the cisco sip ip phone


omphalism is a school of thought ( titled after the philip henry gosse work omphalos ) which holds that the entire universe was created with the appearance of age, and thus no date of creation for the universe can be definitively proven. examples of omphalism : - the belief that our memories, experiences, and physical appearances were " implanted " into us at our creation, possibly at a time during what we imagine to be our own lifetimes. - that nature shows signs of growth, renewal and damage which were posited into being, rather than occurring " naturally ". these include trees ( growth rings, fire scares ), mountains ( upheaval, erosion ), and animals ( offspring or supposed " evolution " ). - that starlight was " already " moving towards earth when god created it, thus disallowing accurate gauging of the universe ' s age. reception among philosophers omphalism has been declaimed by many creationists, as it appears to accuse god of deceit. the movement has been mocked by both creationists and evolutionist atheists as " last thursdayism ", with the claim that the entire universe, with all the appearances of age and function, could very well have been created at some point in the past ( such as " last thursday " ). omphalism occupies a strange place in theology, as, while supporting the notion of god as an omnipotent being, who has provided us with all the signs of a growing, changing word to give our lives context and function ( in addition to instilling many humans with the love and faith of christ ), it does in fact appear to accuse god of deceit, since these emotions and sentiments can be said to be " programmed " into humans ex nihilo. it can thus be described as heretical.


common lisp the language, 2nd edition several kinds of numbers are defined in common lisp. they are divided into integers ; ratios ; floating - point numbers, with names provided for up to four different floating - point representations ; and complex numbers. x3j13 voted in march 1989 ( real - number - type ) to add the type real. the number data type encompasses all kinds of numbers. for convenience, there are names for some subclasses of numbers as well. integers and ratios are of type rational. rational numbers and floating - point numbers are of type real. real numbers and complex numbers are of type number. although the names of these types were chosen with the terminology of mathematics in mind, the correspondences are not always exact. integers and ratios model the corresponding mathematical concepts directly. numbers of type float may be used to approximate real numbers, both rational and irrational. the real type includes all common lisp numbers that represent mathematical real numbers, though there are mathematical real numbers ( irrational numbers ) that do not have an exact common lisp representation. only real numbers may be ordered using the <, >, < =, and > = functions. a translation of an algorithm written in fortran or pascal that uses real data usually will use some appropriate precision of common lisp ' s float type. some algorithms may gain accuracy or flexibility by using common lisp ' s rational or real type instead.


anti de - sitter space bubbles, filaments, voids and sheets condensed matter system cosmic microwave background deep field survey degrees of freedom grand unification theory heisenberg uncertainty principle hubble ' s law and constant intercommuting and loop production laws of thermodynamics nematic liquid crystal quantum field theory speed of light strong and electroweak forces surface of last scattering the great attractor theory of everything when dealing with geometries that take place within the universe, we deal not with conventional three - dimensional euclidean geometry, we have to adapt it to represent a four - dimensional spacetime. this results in what is known as a lorentzian manifold. within this geometry, we deal with three types of space, de - sitter space, anti de - sitter space and minkowski space. they are analogues of spherical, hyperbolic and euclidean space with regards to four - dimensional spacetime. this is a type of hypothetical particle of zero electrical charge that has come out of the framework of quantum chromodynamics. it is hypothesised that these were created during the very early universe. they have little mass and do not easily interact with normal matter. no experimental evidence for them exists as of yet, but they are one of the possible contenders for dark matter. a baryon is a category of subatomic particle which is composed of three quarks. this is opposed to a meson, which is composed of one quark and one antiquark. baryons include protons and neutrons and make up the majority of the mass of visible matter in the universe ( i. e. the mass of the universe that is not dark matter or dark energy ). they participate in the strong nuclear force. about thirteen billion years ago, the universe began in a gigantic explosion. every particle started rushing apart from every other particle in an early super - dense phase. the fact that galaxies are receding from us in all directions is a consequence of this initial explosion. projecting galaxy trajectories backwards in time means that they converge to a high - density state. this is one of the possible ends to the universe as we know it. cosmic inflation is expands the universe and gravitation brings matter together. depending on the density of the universe, one of these forces may overcome the other, or alternatively the universe may be of critical density, which would result in a " flat " universe. if the universe has a density higher than this critical density, then gravitation will eventually overcome the forces working to


these forces may overcome the other, or alternatively the universe may be of critical density, which would result in a " flat " universe. if the universe has a density higher than this critical density, then gravitation will eventually overcome the forces working to expand the universe, and the matter in the universe would start to converge on other matter, until all the matter in the universe converges into a singularity. given that we now know that the expansion of the universe is accelerating, it now seems unlikely that this situation will arise. a black hole is a region of spacetime from which nothing can escape, even light. to see why this happens, imagine throwing a tennis ball into the air. the harder you throw the tennis ball, the faster it is travelling when it leaves your hand and the higher the ball will go before turning back. if you were able to throw it hard enough, it would never return ; the gravitational attraction will not be able to pull it back down. the velocity the ball must have to escape is known as the escape velocity. as a body is crushed into a smaller and smaller volume, the gravitational attraction it exerts increases, and the escape velocity required to overcome this gets bigger. things have to be thrown harder and harder to escape. eventually, a point is reached when even light, which travels at 186 thousand miles a second, is not travelling fast enough to escape. at this point, nothing can get out as nothing can travel faster than light. this is a black hole. black hole formation starts when a large star has burnt all its fuel, exploding into a supernova. what remains after the supernova collapses down into a neutron star, which is extremely dense. if the neutron star is too large, its gravity overwhelms its internal pressure and the star collapses to form a black hole. a blackbody is a theoretical construct that absorbs all radiation that strikes it. no known material absorbs all radiation - some is always reflected off of it. such a body would therefore appear completely black to all types of radiation spectrography. blackbody radiation is radiation emitted from the said theoretical construct, a perfect emission of radiation with 100 % efficiency. at a certain temperature, for example, the blackbody would radiate the maximum amount of energy for that temperature. it must emit this radiation across all possible wavelengths and frequencies and is must also absorb all possible wavelengths and frequencies, which means that it can emit radiation at infinite wavelength. named after indian physicist satyendra nath bose, these are particles


. it must emit this radiation across all possible wavelengths and frequencies and is must also absorb all possible wavelengths and frequencies, which means that it can emit radiation at infinite wavelength. named after indian physicist satyendra nath bose, these are particles with full integer spin, i. e. 1, 2, 3. ( as opposed to fermions, which possess half integer spin ). there are two categories of fundamental boson ( bosons not composed of a combination of other particles ) ; gauge bosons, which mediate the fundamental forces of nature ; and scalar bosons, which are constituents of a scalar field, and include the elusive higgs boson. bosons can also be created from other particles whose spin totals an integer, for example, any meson. brane inflation uses fundamental object of string theory, called branes. in this theory, the universe is a three dimensional slide ( a brane ) in a high dimensional space ( the bulk ), which may also contain other branes. these slices of spacetime have mass and can attract each other by gravity, so two almost parallel branes separated by some distance will start moving towards each other. in brane inflation, the closer the two branes get to each other, the more the branes expand, giving rise to inflation. the process ends with the violent collision of the branes, leading to the copious production of radiation and relativistic particles. hence, the new brane resulting from the collision is filled with a hot plasma, which is the starting point of the standard big bang model. there is another prediction in the model : the collision is also accompanied by the production of cosmic strings. these are all types of large - scale structure formed from galactic distribution in the universe. galaxies form clusters and superclusters which arrange into sheets and filaments through the universe. between these sheets of galaxies, there is very low galaxy density, which leads to voids. these fill approximately 90 % of space. bubble nucleation is a form of first - order phase transition. a phase transition occurs when temperatures and densities increase such that matter changes its form and properties, such as in the very early universe, during the big bang. a simple analogy is water, which melts from ice to liquid, and then boils to gas as temperatures increase. for physicists, it is important to note that as the temperature increases, the symmetry of the matter increases. thinking this through, we know that gas is more symmetry than


colour is a degree of freedom that allows quarks to exist together to form hadrons, such as protons or neutrons, in otherwise identical quantum states. this is necessary as otherwise they would be in violation of the pauli exclusion principle, which states that no two identical fermions may occupy identical quantum states simultaneously. comoving distance is the distance between two objects as it appears if the expansion of the universe is factored out. at any given time, it is equal to the proper distance, which is the actual distance between two objects, and will change over time due to the expansion of the universe. the comoving horizon is therefore the actual distance to the edge of what we can see at any given time. condensed matter systems deal with, as the name suggests, condensed matter. this includes matter in the liquid, solid, superconducting phases. condensed matter systems can be used to study the effects of phase transitions on matter. around 370, 000 years after the big bang, the temperature of the universe dropped sufficiently for electrons and protons to combine into hydrogen atoms : p + e = h. from this time onwards, radiation was effectively unable to interact with the background gas, so it has propagated freely ever since, while constantly losing energy as its wavelength is being stretched by the expansion of the universe. originally, the radiation temperature was about 3000 degrees kelvin ( i. e. approximately 3300 degrees celsius, 5000 degrees fahrenheit ), whereas today it has fallen to only 3k. observers detecting this radiation today are able to see the universe at a very early stage. photons in the cmb have been travelling towards us for over ten billion years, and have covered a distance of about a million, billion, billion miles. the cmb was discovered in 1964. these are one - dimensional ( that is, line - like ) objects which form when an axial or cylindrical symmetry is broken. strings can be associated with grand unified particle physics models, or they can form at the electroweak scale. they are very thin and may stretch across the visible universe. a typical gut ( grand unified theory ) string has a thickness that is less then a trillion times smaller that the radius of an hydrogen atom. still, a 10 km length of one such string will weigh as much as the earth itself! originally proposed by einstein as a modification to general relativity to result in a universe which would neither expand nor contract. he later famously called it his greatest mistake after hubble discovered that other galaxies were moving away


string will weigh as much as the earth itself! originally proposed by einstein as a modification to general relativity to result in a universe which would neither expand nor contract. he later famously called it his greatest mistake after hubble discovered that other galaxies were moving away from us using redshift. different values of the constant can be used to explain different scenarios in which the universe might contract or expand. given that we now know that the expansion of the universe is accelerating, physicists are now looking to the cosmological constant as a possible explanation. specifically, the cosmological constant may be related to the dark energy that pervades our universe, working against gravity to expand the universe. this states that the universe appears the same in every direction from every point in space. it asserts that our position in the universe - on the very largest scales - is in no sense preferred. there is considerable observational evidence for this assertion, including the measured distributions of galaxies and faint radio sources, though the best evidence comes from the near - perfect uniformity of the cosmic microwave background radiation. this means that any observer anywhere in the universe will enjoy much the same view as we do, including the observation that galaxies are moving away from them. it should be noted that this does not mean local structures will be different, i. e. local stars etc. will be different for different observers, but more that the physical laws which govern these observable phenomena will be the same and background effects across the universe will be equal. cosmology is the study of the large scale universe, its origins, evolution, laws and its eventual fate. whereas astronomy is concerned with objects within the universe, cosmologists are more concerned by the universe as a whole. the uk ' s national cosmology supercomputer. it is housed within the department of applied mathematics and theoretical physics, here in cambridge. having recently undergone its ninth iteration, it is the most powerful shared memory system in europe. it is available for use for both academic and non - academic users, and is part of the stfc ' s high - performance computing dirac facility. this reference to the density of our universe. matter density in the universe plays a critical role towards understanding what will happen to the universe in the future, specifically, whether it will continue expanding until perhaps the universe grows so cold that life is unsustainable, or that matter is literally ripped apart, or whether gravitation will eventually overcome expansionary forces and the universe will collapse in some big crunch. a universe with less


continue expanding until perhaps the universe grows so cold that life is unsustainable, or that matter is literally ripped apart, or whether gravitation will eventually overcome expansionary forces and the universe will collapse in some big crunch. a universe with less than critical density will continue expanding at a forever accelerating rate, whereas a supercritical universe will invariably collapse. in the late 1990s, it was discovered that the expansion of the universe is accelerating. it is expected that due to gravity ’ s influence, bringing matter together, would slow down the acceleration of the expansion of the universe. therefore either whatever is responsible for this acceleration is not normal matter, or gravity must get weaker on large scales. this unknown physical phenomenon responsible for this acceleration is known as dark energy. to completely explain the acceleration then there isn ’ t only a little dark energy in the universe, there ’ s a lot of it. in fact, it must make up 74 % of the mass of the universe. dark matter must make up 22 % of the universe, with only 4 % of the universe being the matter that is currently known to us. there is strong evidence that the universe consists primarily of dark ( non - luminous ) matter, also that this matter is of an exotic, non - baryonic form. baryons are made up of three quarks, a type of elementary particle. baryons include protons and neutrons. a deep field survey is a galaxy survey which looks deeper into the sky than the average galaxy survey. because electromagnetic waves have a speed limit ( the speed of light ), the further away from us that we look, the further back in time we are looking, as the waves that are currently reaching us will have been radiated billions of years ago. hubble ultra - deep field, the deepest image of the universe that we currently have, shows us a time period corresponding to roughly 400 - 800 million years after the big bang. a degree of freedom, in physics ( as opposed to mathematics, which can have different meanings ), is a parameter that can help define the state of an object to differentiate it from others. a simple example would be charge amongst particles. some particles are charged, some are not, and as a result they behave differently. at a quantum level this becomes important because certain particles with the same values for their varying degrees of freedom ( i. e. spin, charge etc. ) cannot exist in the same place at the same time. an object which generates a magnetic field emanates that field from two opposite poles


certain particles with the same values for their varying degrees of freedom ( i. e. spin, charge etc. ) cannot exist in the same place at the same time. an object which generates a magnetic field emanates that field from two opposite poles, an example of this would be a bar magnet, which has a north and south pole. each of these poles is a magnetic monopole. the magnet itself, having two of these poles, is a dipole. this is similar to an electric field, in which the field emanates from positive and negative charges. whereas in electricity, negative and positive charges can be easily isolated in the form of electrons and positrons, magnetic monopole particles have yet to be discovered. for example, when you break up a bar magnet, you do not isolate the two monopoles, you simply have two bar magnets half the size of the previous one. these are two - dimensional objects that form when a discrete symmetry is broken at a phase transition. a network of domain walls effectively partitions the universe into various ' cells '. domain walls have some rather peculiar properties. for example, the gravitational field of a domain wall is repulsive rather than attractive. when the source of a wave moves away from us, we observe a change of frequency of that wave. an example would be an ambulance or fire - truck - we hear a lower pitch in its siren once it has passed us by. this is the doppler - shift. it is not, however, limited to sound waves, but any kind of waves, including electromagnetic. ( b. 1879 d. 1955 ), was a german theoretical physicist who spent much of his career at the kaiser wilhelm institute for physics and princeton university. he is regarded as one of the greatest physicists of the 20th century, and indeed, one of the most academically brilliant minds of all time. awarded the nobel prize in physics in 1921, for his work on the photoelectric effect where he described photons as discrete packets, known as quanta. this was in direct conflict with previous, classical descriptions of physics which defined photons as wave. his theories are now the basis of modern physics. these theories, whilst too numerous to list here, include special relativity, which describes how relative motion can result in different laws of physics being experienced by different observers as well as the energy - mass equivalence relationship, e = mc2, and general relativity, which generalises special relativity with respect to gravity and incorporates this with newtonian laws of gravity to describe a


in different laws of physics being experienced by different observers as well as the energy - mass equivalence relationship, e = mc2, and general relativity, which generalises special relativity with respect to gravity and incorporates this with newtonian laws of gravity to describe a how gravity is a geometry property of spacetime. when hitler came to power in 1933, he was on a trip to america and did not return to german, instead opting to become an american citizen. his warning to president roosevelt about the german research into nuclear weapons led to the eventual development of the atomic bomb, a weapon he later denounced and crusaded against. such was einstein ' s genius that upon his death his brain was removed for future study. an elementary particle carrying a negative elementary electric charge ( that is, the most fundamental electric charge, particles do not carry charge smaller than this ). a fermion with spin 1 / 2. it is a lepton and therefore is a constituent of matter, but does not participate in the strong nuclear force. it does interact with electromagnetism, gravitation and the weak nuclear force. energy unit equal to approximately 1. 6 x 10 - 19 joules. it is the amount of energy gained by the charge of one electron as it moves across a one volt electric potential difference. a period in time. in cosmology it is used to refer to different time periods in the chronology of the universe. these include the planck epoch ; the grand unification epoch ; the electroweak epoch ; the quark epoch ; the hadron epoch ; the lepton epoch ; and the photon epoch ( all of the epochs prior to the photon epoch occurred within the first 10 seconds of time! ). time periods after this include nucleosynthesis, recombination and reionization. this is the speed required for any object to break free of another objects gravitational field. for the earth, this is approximately 7, 000 miles per second. mathematically, it is described as the velocity at which the escaping object ' s kinetic energy and gravitational potential energy summate to zero. as the gravitational force exerted by an object on another object increases as the distance between the two decreases, the further away the escaping object is, the lower the escape velocity. for black holes, at the distance known as the event horizon, the escape velocity is greater than the speed of light, and therefore nothing can escape. eternal inflation refers to a series of models by which at least one region of the universe is undergoing inflation at any one point in


the distance known as the event horizon, the escape velocity is greater than the speed of light, and therefore nothing can escape. eternal inflation refers to a series of models by which at least one region of the universe is undergoing inflation at any one point in time. due to the exponential increase in volume during these periods of inflation, it is theorised that at any given point the majority of the volume of the universe is still expanding. this creates a multiverse, whereby each expanding area of the universe appears, to be its own universe, and the beginning period of expansion equivalent to the big bang. in eternal inflation it is possible for these expanding areas of space to decay into a lower energy phase, resulting in inflation ceasing. named after euclid, a greek mathematician of the third century bc. it is a system of geometry based around the geometry of the three dimensions that we are all taught at school ; x, y and z. points within the system can be described by a set of cartesian coordinates. it is described by a system of postulates, or premises, for example, the parallel postulate, which states that " if a straight line falling on two straight lines makes the interior angles on the same side less than two right angles, the two straight lines, if produced indefinitely, meet on that side on which are the angles less than the two right angles ". in contrast to this is non - euclidean geometry, which deals with curved space. the event horizon is the boundary that marks the point where the escape velocity of a black hole exceeds the speed of light. once the event horizon has been crossed, nothing can escape from the black hole ’ s gravitational pull, not even light. exotic particles are those made up of theorised particles not currently part of the standard model. an example of this would be the heavier partners of the current set of particles that make up the standard model, that are described within the theory of supersymmetry. full title : the fermi national accelerator laboratory. located near chicago, il., it is a united states department of energy laboratory focussed on high - energy physics. until 2011, it house the tevatron particle accelerator, which until the opening of the large hadron collider at cern, the largest in the world. in 1995 work done at the tevatron led to the discovery of the top quark, one of the six different flavours of quark, and the most massive of them all. these are particles with half integer spin. this is


world. in 1995 work done at the tevatron led to the discovery of the top quark, one of the six different flavours of quark, and the most massive of them all. these are particles with half integer spin. this is opposed to bosons, which have full integer spin. only one fermion can occupy the same quantum state and space at any given time, this is known as the pauli exclusion principle, and does not apply to the other class of particles, bosons. elementary fermions ( those not composed of other particles ) are constituents of visible matter in the universe, and include electrons and quarks. particles composed of fundamental fermions, however, can have full integer spin and therefore can be classed as bosons. a ferromagnet is an object which exhibits the property of ferromagnetism. ferromagnetism is the strongest type of magnetism, and as such ferromagnets are the magnets that the average reader will be familiar with. they are the ones used in physics classes at school, they are the ones used to pick up scrap metal, they are the magnets on your fridge. ferromagnetism is the only type of magnetism that has the strength to produce a force that can be felt. a ferromagnet can be defined as a material that can exhibit a net magnetic moment in the absence of an external magnetic field. ( b. 1918 - d. 1988 ), was a physicist who spent most of his life working at the california institute of technology ( caltech ). also worked on the manhattan project at los alamos national laboratory, where he helped develop the atomic bomb. won the nobel prize in physics in 1965 for his work in quantum electrodynamics ( qed ). developed the path integral formulation that we use today, and developed an illustrative representation scheme for the behaviour of subatomic particles which has become known as feynman diagrams. caltech has a named chair of physics in his honour. outside of his life in physics, he also was a member of the panel that investigated the space shuttle challenge crash, and wrote two popular science books : " surely you ' re joking, mr. feynman! " and " what do you care what other people think? ". there are four fundamental forces in nature. they are electromagnetism, the weak nuclear force, the strong nuclear force and gravitation. the weak nuclear force is associated with radioactivity


what do you care what other people think? ". there are four fundamental forces in nature. they are electromagnetism, the weak nuclear force, the strong nuclear force and gravitation. the weak nuclear force is associated with radioactivity in unstable nuclei, specifically the decay of a neutron into a proton in the form of beta radiation. the gauge bosons that mediate the force are the w and z bosons. this interaction can cause quarks to change flavours. the strong nuclear force binds together quarks to form nucleons, in turn, it also acts to bind these nucleons together, forming atomic nuclei. the force is mediated by an exchange of gluons, which are a type of gauge boson. the charge associated with this force, analogous to the electric charge associated with electromagnetism, is the colour charge, of which there are three varieties ; red, green and blue. the mathematical theory describing the elementary particles interacting with this force, quarks and gluons, is known as quantum chromodynamics ( qcd ). at atomic levels, it is by far the strongest of all forces, but only interacts on a scale on the order of 10 - 15m, and therefore, whilst incredibly important for the formation of matter, does not play any observable role in day to day life. electromagnetism is a force associated with the electric charge associated with certain molecules. along with gravitation, is is one of the four forces that has a major noticeable effect on day to day human life. it manifests as two different fields electric fields and magnetic fields, although they are aspects of the same force and therefore interact with each other through electromagnetic induction. the gauge boson that mediates this force is the photon, which is also the quanta ( discrete packet ) of light and other forms of electromagnetic radiation, such as infra - red radiation ( most thermal radiation ), x - rays, ultraviolet radiation etc.. gravitation is a force of attraction between two massive bodies. objects on earth are attracted to the earth via gravitation, why is why, when an apple falls from a tree, it falls down towards the earth, instead of in any other direction. gravitation also gives weight to objects, weight being the mass of an object multiplied by the gravitational force acted upon it by another object. gravitation on a universal scale is described by einstein ' s theory of general relativity, where it is described as being


allows us to build up a three dimensional map of the sky, which allows us to gain insight into the large - scale structures within the universe. a gauge group is a set of gauge transformations which effect a system in similar manners. a gauge transformation is a transformation that acts on redundant degrees of freedom within a system, that is, it effects a property that does not really have any physical significance at the level at which the system operates. a gauge transformation which is globally symmetric effects all points of space in the same way. an example of this would be a transformation of voltage that states that voltage1 = voltage2 + c ( a constant ). if we substitute the left hand side of the equation with the right in classical equations dealing with electromagnetism, there is no difference in the outcome and therefore this will hold across any difference in voltage. if we impose a local symmetry on the gauge transformation, also known as gauge invariance, then these transformations become very significant. this is because the transformation holds true, but the transformation is now a function of the position in space and time. through introducing these conditions of gauge invariance into quantum equations, one can extrapolate that for particles that interact with fundamental forces, such as the electron, which carries electrical charge and is acted upon by electromagnetism, there is an underlying field which is also undergoing a gauge transformation. in the case of the electron, it is the electromagnetic field, which physicists were already aware of, however, gauge invariance has postulated the gluon field which is the basis for quantum chromodynamics, the theory which explains the strong nuclear force. this is the modern geometric description of gravity. it says that the gravitational force is related to the curvature of spacetime itself, i. e. to its geometry. to this end, it generalises einstein ' s theory of special relativity, and links it to newton ' s laws of gravity. unlike for non - gravitational physics, spacetime is not just an arena in which physical processes take place, but it is a dynamical field. the gravitational field at a fixed time can be described by the geometry of the three spatial dimensions at that time. these are gauge bosons which mediate the strong nuclear force, one of the fundamental forces. similar to the photons which mediate the electromagnetic force, gluons have no rest mass and so travel at the speed of light. although unlike photons, which whilst mediating the electromagnetic force, are themselves electrically neutral, gluons


. similar to the photons which mediate the electromagnetic force, gluons have no rest mass and so travel at the speed of light. although unlike photons, which whilst mediating the electromagnetic force, are themselves electrically neutral, gluons have charge associated with the strong nuclear force, or colour. there are 8 different colours of gluon. gluons are confined within hadrons, particles made up of quarks ( which have a colour charge ), and are limited in interaction to a distance of approximately 10 - 15 metres. see grand unified theory. in the aftermath of the big bang, the universe was extremely hot and extremely dense. at these energies, the laws of nature that we know were changed. the fundamental forces that we see in nature were unified - the universe was in a state of grand unification - it is only as the universe expanded and cooled that gravitation, electromagnetism and the strong and weak nuclear forces all ceased to be as one. electroweak theory describes the unification of the weak nuclear force and electromagnetism. a grand unified theory will marry up electroweak theory with the strong nuclear force, brining us closer to a unification of the four fundamental forces. gravitational waves are propagating disturbances in spacetime. the effect of a passing gravitational wave is to periodically stretch and compress space in the two directions perpendicular to the direction of propagation. the expected strain on the earth due to these disturbances, which can be caused by black holes merging, is very small, making detection extremely difficult. this is an as yet undiscovered particle that is believed to mediate the force of gravitation. much like the photon, which mediates the electromagnetic force and the gluon which mediates the strong nuclear force, it has no mass, and therefore travels at the speed of light. it has a spins quantum number of 2, and is the only massless particle with that spin number. it has zero electrical charge. experimentally, the graviton is incredibly difficult to observe, and is beyond the reach of current physics. the detection of gravitational waves may lead to some further information about gravitons, but these have not yet been detected. theories of quantum gravity are one of the largest standing issues in cosmology, and there are currently few mathematically consistent theories that can explain it. one of these theories is m - theory, which we believe to be the best explanation at this point in time. this is a type of blackbody radiation emitted by


should contain at most one degree of freedom per planck area. within m - theory, the holographic principle suggests we are the shadows on the wall. the ' room ' is some larger, five - dimensional spacetime and our four - dimensional world is just the boundary of this larger space. if we try to move away from the wall, we are moving into an extra dimension of space - a fifth dimension. ( b. 1889 - d. 1953 ) was one of the main figures of astronomy in the 20th century. using the hooker 100 inch telescope at mount wilson observatory in california, discovered the galaxies are receding away from us and from each other via the changes in frequency that they exhibit - the shifting of frequency of electromagnetic emissions to the red end of the spectrum. this realisation was crucial as evidence for an expanding universe, which, if reversed, supports the notion of a big bang at the beginning of the universe. famously not awarded the nobel prize on the basis that at the time, research in astronomy was not eligible for the nobel prize in physics. hubble ' s law states that all objects in deep space ( i. e. galaxies ) are receding away from us and each other ( as can be seen by the fact that they are doppler - shifted ), and that the velocity of this recession is proportional to their distance away from the earth and other astral bodies. it is summarised mathematically by the equation : v = h0d, where v is the recession velocity, h0 is the hubble constant and d is the distance away from us that the body is. h0 has an approximate value of 70 kms - 1mpc - 1 ( kilometers per second, per megaparsec ), but a there is disagreement over its precise value. according to the theory of inflation, the early universe expanded exponentially fast for a fraction of a second after the big bang. a simple model for the expansion of the universe is to consider the inflation of a balloon. a person at any point on the balloon might consider himself or herself to be at the centre of the expansion, as all neighbouring points are getting further away. during inflation the universe expanded by a factor of about e60 = 1026. this number is a one followed by 26 zeros. it transcends normal political / economic discussions of inflation. this is a hypothetical particle and scalar field associated with the inflation of the universe that occurred moments after the big bang. it is theorized that this occurred because of a phase transition


surfaces of spheres with the three geometry slicing the sphere in half. they can be used to calculate the quantum process of universe creation, which cannot be described using classical general relativity. they only usually exist for small three geometries, corresponding to the creation of a small universe. note that the concept of time does not arise in this process. universe creation is not something that takes place inside some bigger spacetime arena - the instanton describes the spontaneous appearance of a universe from literally nothing. once the universe exists, quantum cosmology can be approximated by general relativity so time appears. there are properties exhibited by cosmic strings. intercommuting refers to a process whereby strings exchange ends whenever they meet. a loop is produced whenever a string intercommutes with itself. although cosmic strings have not been detected, this process of intercommuting can be seen in certain liquid crystals. an interferometer is a machine that uses a process of wave interference to learn about the waves in question. that is, the waves are superimposed upon themselves to discover their properties. kaluza - klein theory is a theory that seeks to unify two of the four fundamental interactions ; gravitation and electromagnetism. a similar theory, electroweak theory, already unifies the weak nuclear force and electromagnetism. its proposals extend general relativity into five - dimensional spacetime. the si ( or base ) unit for temperature measurement. kelvin and celsius have the same magnitude scale, therefore you can transform one kelvin into celsius by adding 273. 16 to the number. whereas the celsius scale was created by dividing the difference in temperature between water freezing and boiling by one hundred and labelling the freezing point of water as 0, 0 kelvin is the point described by lord kelvin ( after whom the unit is named ) as " infinite cold ", or absolute zero. this is the mechanism by which cosmic topological defects form during a phase transition. causal effects in the early universe can only propagate at the speed of light. this means that at a time t, regions of the universe separated by more than a distance d = ct can know nothing about each other. in a symmetry breaking phase transition, different regions of the universe will choose to fall into different minima in the set of possible states. topological defects are precisely the ' boundaries ' between these regions with different choices of minima, and their formation is therefore an inevitable consequence of the fact that different regions cannot agree on their choices. these are laws which define the


the set of possible states. topological defects are precisely the ' boundaries ' between these regions with different choices of minima, and their formation is therefore an inevitable consequence of the fact that different regions cannot agree on their choices. these are laws which define the fundamental physical properties which characterize ) thermodynamic systems. these are temperature, energy and entropy ( a property that works systems towards equilibrium ). they are : the zeroth law : if two systems are in thermal equilibrium with a third, they must be in thermal equilibrium with each other also. the first law : heat and work are forms of energy transfer. this is the law of the conservation of energy. internal energy in a closed system may change if heat or work are transferred in or out of the system. the second law : the entropy of any isolated system not in thermal equilibrium almost always increases. that is, an isolated system will work towards thermal equilibrium. the third law : the entropy of a system approaches a constant value as the temperature approaches zero. this is not, despite the name, a measure of time, but rather a measure of length. it is the length that light will travel in a vacuum in a year, that is 365. 25 days. its exact value is 9, 460, 730, 472, 580, 800 metres, but is approximately given by 9. 4607x1015m. this is calculated by multiplying the number of days ( 365. 25 ) by the number of seconds in each day ( 86, 400 ) and then multiplying that by the speed of light in a vacuum, which is 299, 792, 458 metres per second. in a mathematical function, the highest and lowest values of that function, over the domain of said function, are defined as the maximum or minimum points respectively. a local minimum or maximum value is defined by taking the highest or lowest value in the function over only part of the domain. an example of a function with several local minimum and maximums would be a graph of sin ( x ), which has no overall maximum or minimum value, but several local maximums and minimums of equal respective values. an object ' s ( in our context, an astronomical object ) brightness as measured by the flux, or intensity of electromagnetic radiation, that the object gives out. during the radiation era, shortly after the big bang, the universe consisted of free moving protons, neutrons and electrons and other particles, including helium ions. all radiation was absorbed by these free electrons, making the universe opaque


the object gives out. during the radiation era, shortly after the big bang, the universe consisted of free moving protons, neutrons and electrons and other particles, including helium ions. all radiation was absorbed by these free electrons, making the universe opaque. when the universe was sufficiently expanded the radiation could no longer interact with the electrons, causing the universe became transparent. this process is called decoupling, and it marked the beginning of the matter era. electrons, now no longer absorbing radiation, instead joined with ions to form neutral atoms. through gravity, these atoms clumped together, eventually forming stars, galaxies and other stellar bodies. these are zero - dimensional ( point - like ) objects which form when a spherical symmetry is broken. monopoles are predicted to be supermassive and carry magnetic charge. the existence of monopoles is an inevitable prediction of grand unified theories ( guts ) ; this is one of the puzzles of the standard cosmology. we have five consistent string theories that can describe both the forces and the matter in our universe. we do not, however, have the tools to explore the theories overall possible values of the parameters in the theories. over the past few years, however, we have been able to explore these theories more thoroughly, and we now believe that these five string theories are all different aspects of the same underlying theory : m - theory. m - theory goes beyond string theory, in that it predicts not ten, but eleven dimensions of spacetime. the theory could have as a fundamental object as a membrane, as opposed to a string, which would look like strings when curled up in the eleventh dimension. it is for this reason that the m in m - theory originally referred to a membrane. nowadays, however, the m doesn ’ t specifically refer to anything, and can stand for mystery, or “ mother of all ”, because m - theory is still largely unknown. vast clouds of interstellar dusk, hydrogen, helium and ionized gas. as the mass of a nebula grows due to the slight gravitational attracts of dust towards each other, the mass compacts enough to form stars. other material within the nebula, such as dust, can clump together to form planets and other planetary objects. originally, any large astronomical object was referred to as a nebula - other galaxies, in particular. a liquid crystal is a phase of matter which exhibits properties somewhere between those exhibited by a liquid and solid crystal. when viewed in high resolution, they can appear to be textured, as the molecules may be free


nebula - other galaxies, in particular. a liquid crystal is a phase of matter which exhibits properties somewhere between those exhibited by a liquid and solid crystal. when viewed in high resolution, they can appear to be textured, as the molecules may be free to flow in a limited manner around, provided that they stay within a crystal like structure. liquid crystals are used extensively in televisions and computer screens. the nematic phase of a liquid crystal is temperature dependent. when in this phase, clamitic ( rod - like ) molecules align themselves individually roughly parallel to each other on their long - side axis, in a similar way to cigarettes in a package. the result of this is that the molecules are free - flowing within this directional order. in this phase, the crystals can show signs of intercommuting and loop production, which are properties expected to be exhibited by cosmic strings. a neutron star is formed from the collapse of a larger star which has undergone supernova. these stars, as the name suggests, are composed mostly of neutrons. neutron stars are extremely hot. they typically have masses between about 1 and 2 solar masses ( 1 solar mass is approximately 2x1030kg, which is about 333, 000 times the mass of the earth ), despite being somewhere on the order of 1015 smaller in radius than the sun, which makes them extremely dense. the more compact a neutron star is, the more likely it is to form a black hole. this occurs when the star ' s density become so great that the gravitational force it exerts on itself is greater than its internal pressure, causing a collapse into a black hole. this was developed in 1983 by stephen hawking and james hartle. describes a situation whereby the universe can spontaneously come into existence from literally nothing. once the universe exists, quantum cosmology can be approximated by general relativity so that time appears. a particle is a nucleon if it is a particle that forms an atomic nucleus. there are two nucleons : protons and neutrons. these are complicated manifolds which, like calabi - yau manifolds, may be the space in which six extra dimensions proposed by certain string theories are found within. the study of the universe up to around 10 - 11 seconds after the big bang. during this time, the electroweak and strong forces were unified in a grand unified phase, which quickly changed to separate out strong and the electroweak forces. further on in time the electroweak interaction separated to become electromagnetism


. during this time, the electroweak and strong forces were unified in a grand unified phase, which quickly changed to separate out strong and the electroweak forces. further on in time the electroweak interaction separated to become electromagnetism and the weak nuclear force. it is possible to reach temperature regimes within this cosmology, allowing us to experimentally test theories. speculation, however, is still required within this time period. a mathematical approach to non - gravitational quantum theory, introduced by richard feynman of caltech. in the path integral approach, the probability that a system in an initial state a will evolve to a final state b is given by adding up a contribution from every possible history of the system that starts in a and ends in b. for this reason a path integral is often referred to as a ' sum over histories '. for large systems, contributions from similar histories cancel each other in the sum and only one history is important. this history is the history that classical physics would predict. for example, a system in the starting position of a ball on a non - symmetrical hill. the probability that the system will end up in the final position of the ball at the bottom of the hill on the side that is steepest is given by the summation of the probabilities of all paths that that ball could take, including going down the other side of the hill. for mathematical reasons, path integrals are formulated in a background with four spatial dimensions rather than three spatial dimensions and one time dimension. there is a procedure known as ' analytic continuation ' which is used to convert results expressed in terms of four spatial dimensions into results expressed in terms of three spatial dimensions and one time dimension. this effectively converts one of the spatial dimensions into the time dimension. this spatial dimension is sometimes referred to as ' imaginary ' time because it involves the use of so - called imaginary numbers. the path integral formulation of quantum gravity has many mathematical problems. it is also not clear how it relates to more modern attempts at constructing a theory of quantum gravity such as string / m - theory. however it can be used to correctly calculate quantities that can be calculated independently in other ways e. g. black hole temperatures and entropies. a phase transition is the change in properties and form of matter due to temperature changes. for example, water changes from solid ice to liquid water to gaseous steam or vapour. as temperature drops and phase transitions occur, the symmetry of the resulting matter is reduced - again, vapour is more symmetric than water


due to temperature changes. for example, water changes from solid ice to liquid water to gaseous steam or vapour. as temperature drops and phase transitions occur, the symmetry of the resulting matter is reduced - again, vapour is more symmetric than water, which is more symmetric than ice. in terms of cosmology, when a phase transition in the early universe occurs, topological defects are formed. some of the symmetries that were broken in the early universe led to the four fundamental forces becoming discrete forces. at higher temperatures, they reunite in a unified state. the photon is an elementary particle. it is a gauge boson, in that it mediates one of the fundamental forces. in the case of the photon, it is the electromagnetic force. as mediators of the electromagnetic force, they allow us to see things through the visible light part of the electromagnetic spectrum, and are therefore often interchanged with " light ". as they have no rest mass, they are able to travel at the fastest possible speed, which is know as the " speed of light " ( 299, 792, 458 metres per second ) in a perfect vacuum. their spin is 1 and no electrical charge. this is simply the planck length squared. given that the planck length is a fundamental unit of length, so too is the planck area a fundamental unit of area. this is the size of energy quanta ( discrete packets of energy ) in quantum mechanics - it is therefore the smallest amount of energy that anything can hold. it is the proportionality constant between the energy of a photon and the frequency of the associated electromagnetic wave, as denoted in the planck - einstein equation which links the two : e = hv, where v is frequency, h is planck ' s constant and e is energy. it ' s value is 6. 6260695729×10−34 j. s this is the earliest period of time, from the beginning of time to 10 - 43 seconds after the beginning of time. during this period, the fundamental forces of nature were all unified due to the unimaginable temperature of the universe, and it is believed that gravity was as strong as the other forces ( it is now by far the weakest of the forces ). a very, very small unit of length. its precise value is 1. 61619997x10 - 35m. it is a base unit within the planck unit system and it is calculated using the speed of light, c, planck ' s constant, h and the gravitational