as broadcast equipment becomes more sophisticated, especially in the digital domains, the speed at which information is transferred, processed, etc., through the equipment itself, becomes a very important factor. with computer processors that drive broadcast equipment today operating in the gigahertz range, what good does it do if the remainder of the infrastructure works considerably slower? superconductors will go a long way in resolving this issue. earlier this year, researchers led by dr. jun akimitsu of aoyama gakuin university in tokyo achieved a significant milestone when they announced that magnesium boride, a readily available metal compound known since the 1950s, has unexpectedly turned into the latest breakthrough in superconductors technology. magnesium boride is commonly used in some chemical reactions, but no one had ever tested its worth as a superconductor at low temperatures, where it demonstrates properties of moving electrons with virtually no resistance. after hearing about dr. akimitsu ' s discovery and working with the substance, dr. paul c. canfield, a professor of physics at iowa state university and a researcher at ames laboratory said : “ it ' s a fantastic discovery! we ' ve been able to do a lot of neat stuff with it in the past month. ” the material is very light and, from reports, is easier to work with as compared with the more complex superconducting materials such as the copper oxides, a so - called high - temperature superconductor. the more complex superconducting materials work at higher temperatures, but magnesium boride is comparatively inexpensive, selling for about $ 175 per 100 - gram bottle. dr. canfield said he and his colleagues at iowa state and ames laboratory have worked extensively investigating magnesium boride and have already fashioned superconducting wires by exposing fibers of boron to magnesium vapors. at present, though, the wires are short ; only couple of inches long, and brittle. dr. canfield said : “ it ' s not something you can curl around your finger. ” but then, who ' d want to curl it around their finger? magnesium boride, as a superconductor, is such only at temperatures up to minus 389 degrees, or about 29 degrees higher than any other simple metallic compound. although not the solution, it is being hailed as a significant step in that direction, so stay tuned. send questions and comments to : firstname. lastname @ example. org


combustion efficiency and reduces tailpipe emissions of co. ozone : a compound that is formed when oxygen and other compounds react in sunlight. in the upper atmosphere, ozone protects the earth from the sun ' s ultraviolet rays. though beneficial in the upper atmosphere, at ground level, ozone is called photochemical smog, and is a respiratory irritant and considered a pollutant. particulates : a fine liquid or solid particle such as dust, smoke, fumes, or smog, found in air or emissions. petroleum : any petroleum - based substance comprising a complex blend of hydrocarbons derived from crude oil through the process of separation, conversion, upgrading, and finishing, including motor fuel, jet oil, lubricants, petroleum solvents, and used oil. sulfur : a natural part of petroleum diesel fuel that is reduced during refining due to an epa mandate. sulfur increases petroleum diesel ' s lubricity and therefore engine life. sulfur oxides and sulfides in exhaust emissions are major components of acid rain. transesterfication : a chemical process which reacts an alcohol with the triglycerides contained in vegetable oils and animal fats to produce biodiesel and glycerin. source : department of energy, national biodiesel board and renewable fuels association. information at your fingertips industry association web sites are primed with information on biodiesel and ethanol. visit the following sites to learn more on both topics, including locations on where to purchase biodiesel in your area :


as d. w. notes, the distinction made between " bit - based " and " word - based " stream ciphers in the source you cite is irrelevant to the end - user. for both kinds of stream ciphers ( as well as for block ciphers in streaming modes like ctr or ofb ), the manner in which the keystream is combined with the plaintext is always the same : bitwise xor, which operates at the bit level but is easily parallelized both in hardware and in software. in any case, the actual distinction they seem to be making is between lfsr - based stream ciphers, which sequentially output one bit per iteration, and ciphers such as rc4 ( and, presumably, block ciphers in streaming modes ) which generate their output bitstream in larger chunks. lfsr - based stream ciphers have generally been designed for direct hardware implementation, where they have the advantage of simplicity, but they ' ve traditionally suffered from poor performance in software ; whereas in hardware it ' s easy to shuffle single bits around and combine them using simple logic gates, typical cpus are designed for carrying out higher - level operations on chunks of 8, 16, 32, 64 or 128 bits in parallel. running a cipher that operates on single bits in software thus wastes most of the cpu ' s power, unless the algorithm can be reformulated to operate on many bits in parallel, something that many older lfsr - based cipher designs haven ' t been very well suited for. on the other hand, ciphers like rc4 were designed for software implementation from the beginning, and do very well there. ( although rc4 itself operates on 8 - bit bytes, which is arguably suboptimal for modern high - end cpus, its simplicity still keeps is competitive there. besides, there are still plenty of 8 - bit processors around in embedded devices and such. ) however, they often make use of features that are difficult and costly to implement in hardware, such as access to relatively large amounts of ram ( e. g. 258 bytes for rc4, accessed in an essentially random order ). in recent years, though, the trend in stream cipher design has been towards ciphers that blur these lines, being efficient to implement in both hardware and software. good examples can be found e. g. in the estream portfolio : the trivium cipher, for example, is fundamentally a " bit - based " shift register design, and can indeed be implemented as such if desired ; however


science : balls and ramps these resources explore basic concepts of science related to balls and ramps. learn about the characteristics and properties of balls and ramps, relationship between the physical properties of balls and their motion, and some of the factors that affect the way balls behave. includes lesson plans, experiments, and simulations. there are also links to ethemes resources on force and motion, and gravity. teachengineering : how high can a super ball bounce? students learn about elasticity for super balls ; includes : prerequisite knowledge, learning objectives, materials list, introduction, vocabulary, procedures, safety issues, troubleshooting tips, investigating questions, assessment, activity extensions, and activity scaling advice. pbs kids : balls and ramp this lesson introduces students to the concept of gravity ; includes materials needed and activity instructions. note : this site includes a discussion board ( message board, forum, etc ). in this experiment, students learn about factors such as temperature and construction that affect the height of a ball bouncing. basketball : a physicist party trick through these activities, students learn the relationship between energy of a basketball and how high it bounces. bbc : force and movement play an interactive game and observe the relationship between force, size of a car, and steepness of a ramp. note : the " talk " link leads to a discussion forum. bbc : forces in action observe how far the truck travels with changing the gradient. note : the " talk " link is a link to discussion forum. ramps 1 : let it roll in this lesson, students will explore and measure the rate of spherical objects rolling down a ramp. this experiment aims to help students understand things that affect the distance and speed of objects rolling from ramps. ethemes resource : physics : force and motion these sites cover the basic concepts of physics. learn about force, motion, and friction using interactive simulations where you can manipulate the variables. includes links to an ethemes on simple machines, magnets, and gravity. ethemes resource : physics : gravity these sites explain how the earth ' s gravity works. includes photographs, simulations, videos, hands - on activities, and online quizzes. included are ethemes resources on mass versus weight and force.


and inserting them accurately into the narrow gullets of flowers ( e. g. harder 1983 )... - - allan g. ellis & bruce anderson, 2011. in sebastien patiny, ed., evolution of plant - pollinator relationships ( cambridge university press ) : 237 - 262.... inspired by evolutionary computation, artificial life, multi - agent systems and social cognition, we develop a more realistic distribution of environments. the basic idea is straightforward : intelligence is the result of evolution through millions of generations interacting with other live beings. thus we define intelligence in this context, interacting with other agents of similar intelligence. we formalise the so - called darwin - wallace distribution for agents and environments. despite the many options and the many sources of uncomputability, we claim that, conceptually, the notion of darwin - wallace distribution is useful to re - visit previous definitions of intelligence. the next step is how this notion can be used for agi development and evaluation. we present a procedure which approximates a darwin - wallace distribution by using intelligence tests over environments such that ' certified ' systems are incorporated into the environments, so making them socially more complex... - - jose hernandez - orallo et al., 2011. ' on more realistic environment distributions for defining, evaluating and developing intelligence ' ( http : / / users. dsic. upv. es ) : 3. wallace ' s approach to cosmology shows how the consideration of the conditions necessary for the evolution of life is not wedded to any particular theory of star formation and development but must be used appropriately in any cosmology we pursue... - - john d. barrow, 2011. the book of universes : exploring the limits of the cosmos ( w. w. norton ).... the term used to describe this type of speciation is allopatry, as opposed to sympatry, where ancestral and descendant species coexist in the same environment ( or parapatry if they exist side by side, with a hybridisation zone in between ). if two populations having evolved separately come back in contact later on, the intermediate phenotype of their offspring could make them unfit for either environment, and this would then provide the selective pressure for the selection of additional reproductive barriers, in a process called reinforcement, and often referred to as ' the wallace effect '. indeed, the earliest promoter of the view that reinforcement could occur under the pressure of natural selection was undoubtedly alfred wallace, who disagreed with darwin ' s views


... - - stanley a. sawyer et al., 17 april 2007. proceedings of the national academy of sciences of the united states of america 104 ( 16 ) : 6509. given that phenomena strive for reality - - that is, to become distinct - - then there must by default be a process whereby constitutive elements are demarcated as ' included ' and, of course, an opposite process, whereby elements become the ' excluded '. according to [ charles ] fort : " it is our expression that nothing can attempt to be, except by attempting to exclude something else : that that which is commonly called ' being ' is a state that is wrought more or less definitely proportionately to the appearance of positive difference between that which is included and that which is excluded. " this process leaves a trace, however, in the sense that one cannot subsequently provide a full and comprehensive description of the thing in question. even darwin, fort argued, ' was never able to tell what he meant by a " species ". ' echoing wallace ' s ( 1875 ) earlier concerns over the close - mindedness of modern science, fort argued that this body of knowledge was itself but one instance of localization, wherein an attempt is made to separate out those explanations which are deemed acceptable and proper from those that are not. the raw material of the world becomes organized and interpreted to fit into preconceived notions of how things should work. slowly but surely, this drive towards explanation causes a plethora of facts and events to emerge from this chaotic landscape, each of which is seen to form part of an overarching pattern. ' a theory feels its way through surrounding ignorance, ' he suggested, like ' a wagon train feels its way across a prairie. ' and yet, ' science relates to real knowledge no more than does the growth of a plant, or the organization of a department store, or the development of a nation : that all are assimilative, or organizing, or systematizing processes that represent different attempts to attain the positive state - - the state commonly called heaven, i suppose i mean '... - - deborah dixon, april 2007. cultural geographies 14 ( 2 ) : 193. the conspicuous displays that warn predators of defenses carried by potential prey have been of interest to evolutionary biologists from the time of wallace and darwin to the present day. although most studies implicitly assume that these " aposematic " warning signals simply indicate the presence of some repellent defense such as a toxin, it


small random perturbances of matter can rapidly propagate into large - scale effects that are not easily predictable. scientists sometimes give the example of a caribbean butterfly that by its wings sets off motions of air molecules. these movements might eventually amplify to steer a hurricane from open sea into the american coast. if the butterfly had flapped its wings slightly differently, the hurricane might not have hit land. according to this idea, wallace ' s spirit beings might make infinitesimal adjustments on the subatomic level that would quickly propagate into observable spiritualist effects. one might also propose that they are somehow capable of manipulating the curvature of einstein ' s space - time continuum. they could thus produce gravitational effects, for gravity is said to be the result of curvature in the continuum. or one might propose that the spirit beings induce slight changes in the quantum mechanical vacuum, which in some ways resembles an ether. of course, this approach is limiting, and rather than straining to find ways to explain spiritualist phenomena in conformity with currently accepted physical laws, it may make more sense to come up with a new theoretical system that more naturally incorporates both the normal and paranormal phenomena... - - michael a. cremo, 2003. in his human devolution : a vedic alternative to darwin ' s theory. ( bhaktivedanta book publishing inc. ) : 128.... wallace favored the latter course, but his system has certain puzzling features. although a dualist, he does not appear to accept the existence of individual conscious entities before their earthly embodiment. according to wallace, there is an original spiritual mind from which matter is generated. individual spiritual minds, associated with spiritual bodies ( souls ), are only developed from and in material bodies, as they come into existence ( wallace 1885 ; in smith 1991, p. 100 ). after death, the individual minds, as above stated, go to " the first grade of spirit life, " where they experience progress or the lack of it based on their earthly habits. but if individual spirit souls can exist after earthly embodiment, why not before? and why is there any need at all for earthly embodiment, which is not an altogether pleasant experience? why not skip that and go directly to the highest grade of spiritual life?... - - michael a. cremo, 2003. in his human devolution : a vedic alternative to darwin ' s theory. ( bhaktivedanta book publishing inc. ) :


by carl weese light, natural or artificial, indoors or out, is constantly variable. we notice the warm, reddish light of sunrise and sunset, but there are subtle variations all the time. we generally don ’ t notice the color of ambient light because our eye / mind perceptual system adapts, much as it adapts to changes in light intensity. for example, from outdoors on a dark day, the windows of a house will look yellow if there are tungsten lights inside. the observer standing outside is adapted to the color of daylight and sees the yellow color of the interior light, but if we enter the house we adapt almost immediately. from inside, the room light seems normal while the view out a window can look bright blue. concentrate on what you see through the window, and the color will quickly look right again. the yellow / amber light from a standard light bulb has a lower color temperature than daylight. why is it referred to as temperature? a black body radiator ( think of an iron bar or fireplace poker ) gives off energy in the form of light when it is heated. first it glows ruby red. when it is heated to a temperature of 3200 kelvin, it gives off light the same color as a typical studio photoflood, so the studio lamp is said to have a color temperature of 3200 kelvin and that ’ s the calibration for a typical tungsten color film. sunlight is the color given off by a black body radiator heated to 5000 – 5500k so that ’ s the color temperature daylight film is calibrated for. the color temperature of overcast sky is in the range of 5800 to 7000k, while open shade under a clear blue sky can hit 9000 – 12000k. that ' s why a " warming filter " is needed to keep pictures in shade from looking bright blue on slide film. at the other end, low wattage light bulbs in a living room lamp can be way down around 2000k and candlelight is lower still. these light sources, like the heated iron bar, produce a continuous spectrum of light. the lower temperatures make warmer, redder light, and the higher temperatures produce cooler, bluer, light. fluorescent tubes, sodium - vapor lamps, and other forms of high efficiency energy - saving lighting usually produce a discontinuous spectrum. this means that while the light from a “ daylight ” fluorescent looks somewhat similar to real daylight, it is deficient in specific wavelengths, mostly in the magenta area


key : " s : " = show synset ( semantic ) relations, " w : " = show word ( lexical ) relations display options for sense : ( gloss ) " an example sentence " - s : ( n ) present, nowadays ( the period of time that is happening now ; any continuous stretch of time including the moment of speech ) " that is enough for the present " ; " he lives in the present with no thought of tomorrow " - s : ( n ) present ( something presented as a gift ) " his tie was a present from his wife " - s : ( n ) present, present tense ( a verb tense that expresses actions or states at the time of speaking ) - s : ( v ) show, demo, exhibit, present, demonstrate ( give an exhibition of to an interested audience ) " she shows her dogs frequently " ; " we will demo the new software in washington " - s : ( v ) present, represent, lay out ( bring forward and present to the mind ) " we presented the arguments to him " ; " we cannot represent this knowledge to our formal reason " - s : ( v ) stage, present, represent ( perform ( a play ), especially on a stage ) " we are going to stage ` othello ' " - s : ( v ) present, submit ( hand over formally ) - s : ( v ) present, pose ( introduce ) " this poses an interesting question " - s : ( v ) award, present ( give, especially as an honor or reward ) " bestow honors and prizes at graduation " - s : ( v ) give, gift, present ( give as a present ; make a gift of ) " what will you give her for her birthday? " - s : ( v ) deliver, present ( deliver ( a speech, oration, or idea ) ) " the commencement speaker presented a forceful speech that impressed the students " - s : ( v ) introduce, present, acquaint ( cause to come to know personally ) " permit me to acquaint you with my son " ; " introduce the new neighbors to the community " - s : ( v ) portray, present ( represent abstractly, for example in a painting, drawing, or sculpture ) " the father is portrayed as a good - looking man in this painting " - s : ( v ) confront, face, present ( present somebody with something, usually to accuse or criticize ) " we confronted him with the evidence " ; " he was faced with all the evidence


of either - or. it shows us that there ’ s a way to integrate the advantages of one solution without cancelling out the advantages of an alternative solution. integrative thinking affords us, in the words of the poet wallace stevens, ‘ the choice not between, but of. ” the opposable mind, page 9 the human mind is a wonderful thing. from early in our childhood development, our minds begin to categorize and filter information vital to our survival. through education and experience, we start to qualify objects, people and events as “ safe ” or “ dangerous ”, “ beneficial ” or “ detrimental ”. we do this for our own safety and survival, and we do it unconsciously as we grow. while the function of this process is strictly to keep us safe from physical harm, it actually begins to shape the way we see the world – a lens through which we experience reality, if you will. virtually as soon as we are conscious of our actions, none of us are capable of seeing the world completely objectively, as we all see reality through the tint of our own upbringing. integrative thinking is about testing and expanding our own “ lens ” ( or “ reality - model ”, as martin calls it ) by comparing and contrasting it with the lenses of the people around us, constantly seeking new, better alternatives to all. it ’ s about having a certain level of expectation as to what a solution could look like and refusing to lower that expectation simply because the ideal solution doesn ’ t yet exist. according to martin, there are six beliefs or “ stances ” that are possessed by leaders who practice integrative thinking : belief # 1 : the current solutions or models for a situation are simply the best solutions or models created to date, and not the absolute best solution available. belief # 2 : conflicting solutions or models are not to be feared or resisted, but rather to be learned from, adding to the available data for study and creation of a new, superior model. belief # 3 : better solutions are available, they are just yet to be discovered. belief # 4 : they are personally capable of creating or leading the creation of that better model from abstraction to reality. belief # 5 : “ messiness ” or complexity of options and components is actually a good thing, as it assures no details ( or fewer, at any rate ) are being missed in the creation of an ideal solution. belief # 6 : patience is needed to create the better model. the opposable mind, page 111


so last time, tetra was being enlightened by mc - kun about definitions. this actually arises from mc - kun using prime numbers as a motivating example. primes are megas important in mathematics and even more important today. the entire branch of mathematics called number theory is all about studying the properties of prime numbers. they ’ re so useful that we ’ ve done stuff like extend the notion of prime elements to algebraic structures called rings or apply analytic techniques to learn more about them, but we ’ ll stick with elementary number theory for now. now, for hundreds of years, we ’ d been studying number theory only because it ’ s cool and mathematicians love prime numbers. last time, i mentioned some examples of math preceding useful applications. well, number theory is a really good example of that, because in the 70s, we found a use for it, which is its main use today, in cryptography. there have been some new techniques using some algebra as well, but for the most part, modern cryptography relies on the hardness of factoring primes. neat! okay, so we ’ re back to the original question that mc - kun tries to get tetra to answer, which is, what is a prime number? definition. an integer $ p $ is prime if and only if $ p \ geq 2 $ and the only positive divisors of $ p $ are 1 and itself. mc - kun explains that the motivation for excluding 1 from the definition of a prime number is because we want to be able to say that we can write every number as a unique product of prime numbers. this is very useful, because now we know we can break down every number like this and we can tell them apart because they ’ re guaranteed to have a unique representation. this is called unique prime factorization. theorem. let $ a > 0 $ be an integer. then we can write $ a = p _ 1p _ 2 \ cdots p _ k $ for some primes $ p _ 1, \ dots, p _ k $. this representation is unique up to changing the order of terms. we can show this by induction on $ a $. we ’ ve got $ a = 2 $ so that ’ s pretty obvious. so let ’ s say that every integer $ k \ lt a $ can be decomposed like this and suppose we can ’ t decompose $ a $ into prime numbers, assuming $ a $ itself isn ’ t already a prime since it would just be its own


common divisor of the two numbers, which is just the largest number that divides both of them. we ’ ll denote this by $ \ gcd ( a, b ) $. so since $ p _ i $ is a factor of $ n $, we ’ ve got $ \ gcd ( n, p _ i ) = p _ i $. but then that gives us $ p _ i = \ gcd ( n, p _ i ) = \ gcd ( p _ i, 1 ) = 1 $ by a lemma that says that for $ a = qb + r $, we have $ \ gcd ( a, b ) = \ gcd ( b, r ) $. this means that we have $ p _ i = 1 $, which is a contradiction, since 1 isn ’ t a prime number, and so i guess there are actually infinitely many primes. so the nice thing is that we won ’ t run out of prime numbers anytime soon, which is very useful because as we get more and more computing power, we ’ ll have to increase the size of the keys we use in our cryptosystems. luckily, because factoring is so hard, we don ’ t need to increase that size very much before we ’ re safe for a while. or at least until we develop practical quantum computers.


is defined as heading in the opposite direction of the flow of electrons, thus we get an electric current in which the p - type silicon is an anode and the n - type silicon a cathode. mechanism by which application of a current produces light since exposing a pn junction diode to light produces an electric current just like a solar battery, the reverse should also hold true, i. e. applying an external electric current in the opposite direction should cause light to emit from the pn junction. this phenomenon does in fact occur. making the n - type silicon the cathode and the p - type silicon the anode produces light. this is known as a light - emitting diode ( led ). however, light emission from such rudimentary leds is inefficient, making them ill suited for practical applications. only after creating pn junctions using semiconductor materials made of the compounds gallium arsenide, gallium phosphide, and gallium arsenide phosphide did leds become practical. semiconductor lasers also use pn junctions the semiconductor laser is another technology that uses pn junctions. creating a pn junction within a semiconductor brings about " population inversion " by means of the electrons that flow into n - type silicon and the electron holes in p - type silicon. by skillfully placing two perpendicular mirrors with cleavage planes of semiconductor crystal on either end of the pn junction, we can intensify light by making it bounce back and forth between the planes, thus producing a laser beam comprising light with uniform phase and direction. such semiconductor lasers are also called laser diodes. these devices are only about 300 micrometers square and 80 micrometers thick. laser diodes using gallium arsenide phosphide, which emit a laser beam with a wavelength of 700 nanometers, are being mass produced for use in compact disc ( cd ) players and laser beam printers.


1. the unit of frequency. 4. ( zoology ) lacking a tail or taillike appendage. 12. piece of solid food for dipping in a liquid. 15. resinlike substance secreted by certain lac insects. 16. ornamental objects of no great value. 17. any of various primates with short tails or no tail at all. 18. to make a mistake or be incorrect. 19. third month of the revolutionary calendar ( november and december ). 20. god of the earth. 21. ( anatomy ) of or relating to the fauces. 23. ( norse mythology ) one of the aesir known for his beauty and skill with bow and skis. 24. type genus of the phocidae. 26. the jewish rite of circumcision performed on a male child on the eighth day of his life. 27. a state in new england. 29. become imbued. 31. a state in east central united states. 32. port city of denmark in eastern jutland. 36. a white soft metallic element that tarnishes readily. 37. a soft white precious univalent metallic element having the highest electrical and thermal conductivity of any metal. 39. a rare silvery ( usually trivalent ) metallic element. 41. an island republic on nauru island. 42. a family of birds of the suborder oscines. 46. a ballplayer who is batting. 48. an informal term for a father. 49. the seventh month of the moslem calendar. 51. any of various young herrings ( other than brislings ) canned as sardines in norway. 52. jordan ' s port. 54. a city in northwestern turkey. 55. small cubes with 1 to 6 spots on the faces. 56. fallow deer. 60. a hard brittle blue - white multivalent metallic element. 61. a loloish language. 62. a fraudulent business scheme. 64. indonesian statesman who obtained the independence of indonesia from the netherlands in 1949 and served as president until ousted by suharto in a coup d ' etat ( 1901 - 1970 ). 69. ( akkadian ) god of wisdom. 71. small terrestrial lizard of warm regions of the old world. 74. title for a civil or military leader ( especially in turkey ). 75. ( used especially of glances ) directed to one side with or as if with doubt or suspicion or envy. 78. toward the mouth or oral region. 79. an advanced law


tim turner, the reliability center business development manager at the college of nanoscale science and engineering ( cnse ), albany, ny, blogs about the potential of resistive memory and the reliability challenges the must be overcome. resistive memory, rram or memristors is a hot topic right now. rram has the potential for single digit nano parameters ( speed as fast as 1 ns, area per bit as small as 5 square nm ) and is non - volatile. the technology is based on the formation of a small conductive filament inside an insulator. the filament is formed the first time using a high voltage. after that, set or reset transformation ( conductive to non - conductive or visa versa ) is accomplished by moving one or a few atoms an atomic scale distance. this can be done with a low voltage ( less than a volt ). this small movement gives a repeatable set or reset that can withstand many cycles. conduction in the filament appears to be due to oxygen vacancies existing in a percolation path through the insulator. a small electric field in the reverse direction causes the migration of these oxygen vacancies in a mechanism similar to electromigration of al or cu atoms in a metal line. momentum exchange between electrons and the vacancies appears to be the driving force. the vacancies do not have to move far to open the small filament. an oxygen vacancy moves an atomic scale distance and the tiny filament opens, allowing an insulator to exist between points in the filament. forcing a forward voltage can move the oxygen vacancy back into the area where the filament is conductive. this small movement can give a 100x change in the conduction through the dielectric. this is the state change that can be interpreted as the digital signal stored on the memory cell. the material set used for rram is cmos compatible. rram cells have been made out of cu / hfox, al / alox / pt, tin / alox / pt or even al / alox / cnt ( carbon nano tubes ). most of the work reported to date has been on arrays where the cell is similar to a dram, using one transistor and one capacitor. the rram cell starts with a capacitor, then forms the filament in the capacitor dielectric. the advantage this technology has is the smaller size of the capacitor. there is


##een and brattain ’ s invention of the bipolar, point - contact transistor took many unexpected twists and turns. shockley did not put all his eggs in the field - effect basket. not to be outdone by bardeen and brattain, shockley secretly worked on a different bipolar device. within a short time, his patent for the bipolar junction transistor had wiped out all commercial interest in the point - contact transistor. shockley remained committed to the value of his field - effect theory, but was unable to make a go of it. more than 15 years of material technology advances would be needed before the first practical fet appeared. today, 75 years after lilienfeld ’ s work, metal - oxide silicon ( mos ) transistors, which are built around field - effect principles, dominate semiconductor electronics. lilienfield acknowledged as pioneer in an address to the american institute of physics in 1988, bardeen acknowledged the great credit due lilienfeld for his pioneering efforts to make the semiconductor amplifier. in the 1920s, lilienfeld could not have understood the physics of the field - effect semiconductor amplifier, as the quantum theory of solids was still several years away. nevertheless, he had a good intuitive feel for a new approach to electronics. in bardeen ’ s own words, “ lilienfeld had the basic concept of controlling the flow of current in a semiconductor to make an amplifying device. it took many years of theory development and material technology to make his dream a reality. ”