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it ' s normal for parents to disagree and argue from time to time. parents might disagree about money, home chores, or how to spend time. they might disagree about big things β like important decisions they need to make for the family. they might even disagree about little things that don ' t seem important at all β like what ' s for dinner or what time someone gets home. sometimes parents can disagree with each other and still manage to talk about it in a calm way, where both people get a chance to listen and to talk. but many times when parents disagree, they argue. an argument is a fight using words. most kids worry when their parents argue. loud voices and angry words parents might use can make kids feel scared, sad, or upset. even arguments that use silence β like when parents act angry and don ' t talk to each other at all β can be upsetting for kids. if the argument has anything to do with the kids, kids might think they have caused their parents to argue and fight. if kids think it ' s their fault, they might feel guilty or even more upset. but parents ' behavior is never the fault of kids. what does it mean when parents fight? kids often worry about what it means when parents fight. they might jump to conclusions and think arguments mean their parents don ' t love each other anymore. they might think it means their parents will get a divorce. but parents ' arguments usually don ' t mean that they don ' t love each other or that they ' re getting a divorce. most of the time the arguments are just a way to let off steam when parents have a bad day or feel stressed out over other things. most people lose their cool now and then. just like kids, when parents get upset they might cry, yell, or say things they don ' t really mean. sometimes an argument might not mean anything except that one parent or both just lost their temper. just like kids, parents might argue more if they ' re not feeling their best or are under a lot of stress from a job or other worries. kids usually feel upset when they see or hear parents arguing. it ' s hard to hear the yelling and the unkind words. seeing parents upset and out of control can make kids feel unprotected and scared. kids might worry about one parent or the other during an argument. they might worry that one parent may feel especially sad or hurt because of being yelled at by the other parent. they might worry that one parent seems angry enough to lose control.
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s planetary protection protocols that were established to minimize the chance of contaminating any indigenous life - potential material with hitchhiking microbes from earth. scientists don ' t believe mercury is or was suitable for ancient life, but the discovery of organics on an inner planet of the solar system may shed light on how life got started on earth and how life may evolve on planets beyond the solar system. " finding a place in the inner solar system where some of these same ingredients that may have led to life on earth are preserved for us is really exciting, " paige said. messenger, which stands for mercury surface, space environment, geochemistry and ranging, is due to complete its two - year mission at mercury in march. scientists are seeking nasa funding to continue operations for at least part of a third year. the probe will remain in mercury ' s orbit until the planet ' s gravity eventually causes it to crash onto the surface. whether the discovery of organics now prompts nasa to select a crash zone rather than leave it up to chance remains to be seen. microbes that may have hitched a ride on messenger likely have been killed off by the harsh radiation environment at mercury. the research is published in this week ' s edition of the journal science. ( editing by kevin gray and vicki allen )
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very good series of infographics explaining the economy. it β s called all about the benjamins. videos & slideshows : boomtown to bust is a new york times slideshow on the recession β s effect in florida. the sacramento bee has a series of photos chronicling the economic downturn. long lines of job seekers continue is a slideshow from the washington post. downturn leaves more families homeless is another slideshow from the washington post. the wall street journal has excerpts from recent songs that have been written about the recession. following a closing, the struggle to find work is another slideshow from the new york times. a community facing hunger is a video from the new york times. out of work in china is a video showing the effects of the recession in that country. a painful return is a slideshow discussing the recession β s effects in china. tough times for summitville tiles is a wall street journal slideshow about the closing of a factory. black thursday in france is a wall street journal slideshow about protests in that country demanding that the government do more to stop the recession. ohio town faces economic collapse is a slideshow from pixcetra. the american economy : down and out is a slideshow from time magazine. tough times in cleveland is another time slideshow. an audio slideshow from the new york times called in economic vise, pontiac struggles. there goes retirement is an online video from the wall street journal. the progressive magazine the nation has a useful slideshow called the great recession. it β s a bit ideological, but provides a different kind of analysis and response to the recession. it also includes links to articles that would not be accessible to ell β s. however, the images, teacher modifications of the articles, and lesson ideas provided by them could offer some good opportunities for student discussion and higher order thinking. the faces of the unemployed is a slideshow from the new york times. searching for a job is a series of photos from the sacramento bee. looking for work is an audio slideshow from reuters. desperately seeking a salary is another audio slideshow from reuters. job seekers flood local job fair is a slideshow from the sacramento bee. recession hits the saddle is a slideshow from the new york times. auto town struggles with unemployment is a slideshow from the new york times. dark stores from time magazine. the new york times has an audio slideshow about people looking for work in the state of tennessee. inside california β s tent cities is the newest addition to this list. it
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a nuzzle of the neck, a stroke of the wrist, a brush of the knee β these caresses often signal a loving touch, but can also feel highly aversive, depending on who is delivering the touch, and to whom. interested in how the brain makes connections between touch and emotion, neuroscientists at the california institute of technology ( caltech ) have discovered that the association begins in the brain β s primary somatosensory cortex, a region that, until now, was thought only to respond to basic touch, not to its emotional quality. β we demonstrated for the first time that the primary somatosensory cortex β the brain region encoding basic touch properties such as how rough or smooth an object is β also is sensitive to the social meaning of a touch, β explains michael spezio, a visiting associate at caltech who is also an assistant professor of psychology at scripps college in claremont, california. β it was generally thought that there are separate brain pathways for how we process the physical aspects of touch on the skin and for how we interpret that touch emotionally β that is, whether we feel it as pleasant, unpleasant, desired, or repulsive. our study shows that, to the contrary, emotion is involved at the primary stages of social touch. β
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we have in this chapter to consider why the females of many birds have not acquired the same ornaments as the male ; and why, on the other hand, both sexes of many other birds are equally, or almost equally, ornamented? in the following chapter we shall consider the few cases in which the female is more conspicuously coloured than the male. in my origin of species * i briefly suggested that the long tail of the peacock would be inconvenient and the conspicuous black colour of the male capercailzie dangerous, to the female during the period of incubation : and consequently that the transmission of these characters from the male to the female offspring had been checked through natural selection. i still think that this may have occurred in some few instances : but after mature reflection on all the facts which i have been able to collect, i am now inclined to believe that when the sexes differ, the successive variations have generally been from the first limited in their transmission to the same sex in which they first arose. since my remarks appeared, the subject of sexual colouration has been discussed in some very interesting papers by mr. wallace, * ( 2 ) who believes that in almost all cases the successive variations tended at first to be transmitted equally to both sexes ; but that the female was saved, through natural selection, from acquiring the conspicuous colours of the male, owing to the danger which she would thus have incurred during incubation. * fourth edition, 1866, p. 241. * ( 2 ) westminster review, july, 1867. journal of travel, vol. i., 1868, p. 73. this view necessitates a tedious discussion on a difficult point, namely, whether the transmission of a character, which is at first inherited by both sexes can be subsequently limited in its transmission to one sex alone by means of natural selection. we must bear in mind, as shewn in the preliminary chapter on sexual selection, that characters which are limited in their development to one sex are always latent in the other. an imaginary illustration will best aid us in seeing the difficulty of the case ; we may suppose that a fancier wished to make a breed of pigeons, in which the males alone should be coloured of a pale blue, whilst the females retained their former slaty tint. as with pigeons characters of all kinds are usually transmitted to both sexes equally, the fancier would have to try to convert this latter form of inheritance into sexually - limited transmission. all that he could do would be to persevere in selecting
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coloured birds, which are almost always hens ; and he himself has bred ten such females. it is on the other hand a very unusual event when a silver male is produced ; so that nothing would be easier, if desired, than to make a breed of dragons with blue males and silver females. this tendency is indeed so strong that when mr. tegetmeier at last got a silver male and matched him with one of the silver females, he expected to get a breed with both sexes thus coloured ; he was however disappointed, for the young male reverted to the blue colour of his grandfather, the young female alone being silver. no doubt with patience this tendency to reversion in the males, reared from an occasional silver male matched with a silver hen, might be eliminated, and then both sexes would be coloured alike ; and this very process has been followed with success by mr. esquilant in the case of silver turbits. * dr. chapius, le pigeon voyageur belge, 1865, p. 87. * ( 2 ) the field, sept., 1872. with fowls, variations of colour, limited in their transmission to the male sex, habitually occur. when this form of inheritance prevails, it might well happen that some of the successive variations would be transferred to the female, who would then slightly resemble the male, as actually occurs in some breeds. or again, the greater number, but not all, of the successive steps might be transferred to both sexes, and the female would then closely resemble the male. there can hardly be a doubt that this is the cause of the male pouter pigeon having a somewhat larger crop, and of the male carrier pigeon having somewhat larger wattles, than their respective females ; for fanciers have not selected one sex more than the other, and have had no wish that these characters should be more strongly displayed in the male than in the female, yet this is the case with both breeds. the same process would have to be followed, and the same difficulties encountered, if it were desired to make a breed with the females alone of some new colour. lastly, our fancier might wish to make a breed with the two sexes differing from each other, and both from the parent species. here the difficulty would be extreme, unless the successive variations were from the first sexually limited on both sides, and then there would be no difficulty. we see this with the fowl ; thus the two sexes of the pencilled hamburghs differ greatly from each
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difficulty would be extreme, unless the successive variations were from the first sexually limited on both sides, and then there would be no difficulty. we see this with the fowl ; thus the two sexes of the pencilled hamburghs differ greatly from each other, and from the two sexes of the aboriginal gallus bankiva ; and both are now kept constant to their standard of excellence by continued selection, which would be impossible unless the distinctive characters of both were limited in their transmission. the spanish fowl offers a more curious case ; the male has an immense comb, but some of the successive variations, by the accumulation of which it was acquired, appear to have been transferred to the female ; for she has a comb many times larger than that of the females of the parent species. but the comb of the female differs in one respect from that of the male, for it is apt to lop over ; and within a recent period it has been ordered by the fancy that this should always be the case, and success has quickly followed the order. now the lopping of the comb must be sexually limited in its transmission, otherwise it would prevent the comb of the male from being perfectly upright, which would be abhorrent to every fancier. on the other hand, the uprightness of the comb in the male must likewise be a sexually - limited character, otherwise it would prevent the comb of the female from lopping over. from the foregoing illustrations, we see that even with almost unlimited time at command, it would be an extremely difficult and complex, perhaps an impossible process, to change one form of transmission into the other through selection. therefore, without distinct evidence in each case, i am unwilling to admit that this has been effected in natural species. on the other hand, by means of successive variations, which were from the first sexually limited in their transmission, there would not be the least difficulty in rendering a male bird widely different in colour or in any other character from the female ; the latter being left unaltered, or slightly altered, or specially modified for the sake of protection. as bright colours are of service to the males in their rivalry with other males, such colours would be selected whether or not they were transmitted exclusively to the same sex. consequently the females might be expected often to partake of the brightness of the males to a greater or less degree ; and this occurs with a host of species. if all the successive variations were transmitted equally to both sexes, the females would be indistinguishable from the males
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to partake of the brightness of the males to a greater or less degree ; and this occurs with a host of species. if all the successive variations were transmitted equally to both sexes, the females would be indistinguishable from the males ; and this likewise occurs with many birds. if, however, dull colours were of high importance for the safety of the female during incubation, as with many ground birds, the females which varied in brightness, or which received through inheritance from the males any marked accession of brightness, would sooner or later be destroyed. but the tendency in the males to continue for an indefinite period transmitting to their female offspring their own brightness, would have to be eliminated by a change in the form of inheritance ; and this, as shewn by our previous illustration, would be extremely difficult. the more probable result of the long - continued destruction of the more brightly - coloured females, supposing the equal form of transmission to prevail would be the lessening or annihilation of the bright colours of the males, owing to their continual crossing with the duller females. it would be tedious to follow out all the other possible results ; but i may remind the reader that if sexually limited variations in brightness occurred in the females, even if they were not in the least injurious to them and consequently were not eliminated, yet they would not be favoured or selected, for the male usually accepts any female, and does not select the more attractive individuals ; consequently these variations would be liable to be lost, and would have little influence on the character of the race ; and this will aid in accounting for the females being commonly duller - coloured than the males. in the eighth chapter instances were given, to which many might here be added, of variations occurring at various ages, and inherited at the corresponding age. it was also shewn that variations which occur late in life are commonly transmitted to the same sex in which they first appear ; whilst variations occurring early in life are apt to be transmitted to both sexes ; not that all the cases of sexually - limited transmission can thus be accounted for. it was further shewn that if a male bird varied by becoming brighter whilst young, such variations would be of no service until the age for reproduction had arrived, and there was competition between rival males. but in the case of birds living on the ground and commonly in need of the protection of dull colours, bright tints would be far more dangerous to the young and inexperienced than to the adult males. consequently the males which
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was competition between rival males. but in the case of birds living on the ground and commonly in need of the protection of dull colours, bright tints would be far more dangerous to the young and inexperienced than to the adult males. consequently the males which varied in brightness whilst young would suffer much destruction and be eliminated through natural selection ; on the other hand, the males which varied in this manner when nearly mature, notwithstanding that they were exposed to some additional danger, might survive, and from being favoured through sexual selection, would procreate their kind. as a relation often exists between the period of variation and the form of transmission, if the bright - coloured young males were destroyed and the mature ones were successful in their courtship, the males alone would acquire brilliant colours and would transmit them exclusively to their male offspring. but i by no means wish to maintain that the influence of age on the form of transmission, is the sole cause of the great difference in brilliancy between the sexes of many birds. when the sexes of birds differ in colour, it is interesting to determine whether the males alone have been modified by sexual selection, the females having been left unchanged, or only partially and indirectly thus changed ; or whether the females have been specially modified through natural selection for the sake of protection. i will therefore discuss this question at some length, even more fully than its intrinsic importance deserves ; for various curious collateral points may thus be conveniently considered. before we enter on the subject of colour, more especially in reference to mr. wallace ' s conclusions, it may be useful to discuss some other sexual differences under a similar point of view. a breed of fowls formerly existed in germany * in which the hens were furnished with spurs ; they were good layers, but they so greatly disturbed their nests with their spurs that they could not be allowed to sit on their own eggs. hence at one time it appeared to me probable that with the females of the wild gallinaceae the development of spurs had been checked through natural selection, from the injury thus caused to their nests. this seemed all the more probable, as wing - spurs, which would not be injurious during incubation, are often as well developed in the female as in the male ; though in not a few cases they are rather larger in the male. when the male is furnished with leg - spurs the female almost always exhibits rudiments of them, - the rudiment sometimes consisting of a mere scale, as in gallus. hence it might be argued that the females had
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' s pheasant it is sometimes actually seventy - two inches long in the male and sixteen in the female. thus in the several species, the tail of the female differs much in length, irrespectively of that of the male ; and this can be accounted for, as it seems to me, with much more probability, by the laws of inheritance, - that is by the successive variations having been from the first more or less closely limited in their transmission to the male sex than by the agency of natural selection, resulting from the length of tail being more or less injurious to the females of these several allied species. we may now consider mr. wallace ' s arguments in regard to the sexual colouration of birds. he believes that the bright tints originally acquired through sexual selection by the males would in all, or almost all cases, have been transmitted to the females, unless the transference had been checked through natural selection. i may here remind the reader that various facts opposed to this view have already been given under reptiles, amphibians, fishes and lepidoptera. mr. wallace rests his belief chiefly, but not exclusively, as we shall see in the next chapter, on the following statement, * that when both sexes are coloured in a very conspicuous manner, the nest is of such a nature as to conceal the sitting bird ; but when there is a marked contrast of colour between the sexes, the male being gay and the female dull - coloured, the nest is open and exposes the sitting bird to view. this coincidence, as far as it goes, certainly seems to favour the belief that the females which sit on open nests have been specially modified for the sake of protection ; but we shall presently see that there is another and more probable explanation, namely, that conspicuous females have acquired the instinct of building domed nests oftener than dull - coloured birds. mr. wallace admits that there are, as might have been expected, some exceptions to his two rules, but it is a question whether the exceptions are not so numerous as seriously to invalidate them. * journal of travel, edited by a. murray, vol. i., 1868, p. 78. there is in the first place much truth in the duke of argyll ' s remark * that a large domed nest is more conspicuous to an enemy, especially to all tree - haunting carnivorous animals, than a smaller open nest. nor must we forget that with many birds which build open nests, the male sits on the eggs and aids the female in feeding the
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subdomain_quantum_gravity
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relate to species which build domed or concealed nests. but similar gradations may likewise be observed in groups in which the sexes as a general rule resemble each other, but which build open nests. as i have before instanced the australian parrots, so i may here instance, without giving any details, the australian pigeons. * it deserves especial notice that in all these cases the slight differences in plumage between the sexes are of the same general nature as the occasionally greater differences. a good illustration of this fact has already been afforded by those kingfishers in which either the tail alone or the whole upper surface of the plumage differs in the same manner in the two sexes. similar cases may be observed with parrots and pigeons. the differences in colour between the sexes of the same species are, also, of the same general nature as the differences in colour between the distinct species of the same group. for when in a group in which the sexes are usually alike, the male differs considerably from the female, he is not coloured in a quite new style. hence we may infer that within the same group the special colours of both sexes when they are alike, and the colours of the male, when he differs slightly or even considerably from the female, have been in most cases determined by the same general cause ; this being sexual selection. * gould ' s handbook of the birds of australia, vol. ii., pp. 109 - 149. it is not probable, as has already been remarked, that differences in colour between the sexes, when very slight, can be of service to the female as a protection. assuming, however, that they are of service, they might be thought to be cases of transition ; but we have no reason to believe that many species at any one time are undergoing change. therefore we can hardly admit that the numerous females which differ very slightly in colour from their males are now all commencing to become obscure for the sake of protection. even if we consider somewhat more marked sexual differences, is it probable, for instance, that the head of the female chaffinch, - the crimson on the breast of the female bullfinch, - the green of the female greenfinch, - the crest of the female golden - crested wren, have all been rendered less bright by the slow process of selection for the sake of protection? i cannot think so ; and still less with the slight differences between the sexes of those birds which build concealed nests. on the other hand, the differences in colour between the sexes, whether great or small
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slow process of selection for the sake of protection? i cannot think so ; and still less with the slight differences between the sexes of those birds which build concealed nests. on the other hand, the differences in colour between the sexes, whether great or small, may to a large extent be explained on the principle of the successive variations, acquired by the males through sexual selection, having been from the first more or less limited in their transmission to the females. that the degree of limitation should differ in different species of the same group will not surprise any one who has studied the laws of inheritance, for they are so complex that they appear to us in our ignorance to be capricious in their action. * * see remarks to this effect in variation of animals and plants under domestication, vol. ii., chap. xii. as far as i can discover there are few large groups of birds in which all the species have both sexes alike and brilliantly coloured, but i hear from mr. sclater, that this appears to be the case with the musophagae or plantain - eaters. nor do i believe that any large group exists in which the sexes of all the species are widely dissimilar in colour : mr. wallace informs me that the chatterers of s. america ( cotingidae ) offer one of the best instances ; but with some of the species, in which the male has a splendid red breast, the female exhibits some red on her breast ; and the females of other species shew traces of the green and other colours of the males. nevertheless we have a near approach to close sexual similarity or dissimilarity throughout several groups : and this, from what has just been said of the fluctuating nature of inheritance, is a somewhat surprising circumstance. but that the same laws should largely prevail with allied animals is not surprising. the domestic fowl has produced a great number of breeds and sub - breeds, and in these the sexes generally differ in plumage ; so that it has been noticed as an unusual circumstance when in certain sub - breeds they resemble each other. on the other hand, the domestic pigeon has likewise produced a vast number of distinct breeds and sub - breeds, and in these, with rare exceptions, the two sexes are identically alike. therefore if other species of gallus and columba were domesticated and varied, it would not be rash to predict that similar rules of sexual similarity and dissimilarity, depending on the form of transmission, would
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are identically alike. therefore if other species of gallus and columba were domesticated and varied, it would not be rash to predict that similar rules of sexual similarity and dissimilarity, depending on the form of transmission, would hold good in both cases. in like manner the same form of transmission has generally prevailed under nature throughout the same groups, although marked exceptions to this rule occur. thus within the same family or even genus, the sexes may be identically alike, or very different in colour. instances have already been given in the same genus, as with sparrows, flycatchers, thrushes and grouse. in the family of pheasants the sexes of almost all the species are wonderfully dissimilar, but are quite alike in the eared pheasant or crossoptilon auritum. in two species of chloephaga, a genus of geese, the male cannot be distinguished from the females, except by size ; whilst in two others, the sexes are so unlike that they might easily be mistaken for distinct species. * * the ibis, vol. vi., 1864, p. 122. the laws of inheritance can alone account for the following cases, in which the female acquires, late in life, certain characters proper to the male, and ultimately comes to resemble him more or less completely. here protection can hardly have come into play. mr. blyth informs me that the females of oriolus melanocephalus and of some allied species, when sufficiently mature to breed, differ considerably in plumage from the adult males ; but after the second or third moults they differ only in their beaks having a slight greenish tinge. in the dwarf bitterns ( ardetta ), according to the same authority, " the male acquires his final livery at the first moult, the female not before the third or fourth moult ; in the meanwhile she presents an intermediate garb, which is ultimately exchanged for the same livery as that of the male. " so again the female falco peregrinus acquires her blue plumage more slowly than the male. mr. swinhoe states that with one of the drongo shrikes ( dicrurus macrocercus ) the male, whilst almost a nestling, moults his soft brown plumage and becomes of a uniform glossy greenish - black ; but the female retains for a long time the white striae and spots on the axillary feathers ; and does not
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use of biomedical engineering and music for k - 12 math / science education the study proposes the use of biomedical engineering ( bme ) ph. d. track graduate students to assist middle and high school teachers to teach math / science skills, by providing additional tools and training to optimize their use. the emphasis is on the use of disciplinary knowledge to enhance how people learn with the aid of computer technology ; showing the students the importance of this knowledge to solve real world problems. three school districts have committed to participate in a cross - disciplinary education program ( shelby county, shades mountain independent, and the alabama school of fine arts ). students from uab β s biomedical engineering ( bme ) and the alabama school of fine arts ( asfa ) departments will develop, implement, and evaluate the four interventions used to enhance math / science skills. - music education - math / science kits and six - week projects - science fair project development - a technology of fine arts class when the cost - effectiveness of each intervention has been determined, decisions whether to expand the intervention, within each school system will be made. information about successful programs would be made available, on the internet or other media, to interested groups. trained personnel from this project would serve as facilitators for these groups. - investigators : a. eberhardt, r. thompson, m. froning, d. kilpadi
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the list is the origin of culture. it ' s part of the history of art and literature. what does culture want? to make infinity comprehensible. it also wants to create order β not always, but often. and how, as a human being, does one face infinity? how does one attempt to grasp the incomprehensible? through lists, through catalogs, through collections in museums and through encyclopedias and dictionaries. there is an allure to enumerating how many women don giovanni slept with : it was 2, 063, at least according to mozart ' s librettist, lorenzo da ponte. we also have completely practical lists β the shopping list, the will, the menu β that are also cultural achievements in their own right. β¦ at first, we think that a list is primitive and typical of very early cultures, which had no exact concept of the universe and were therefore limited to listing the characteristics they could name. but, in cultural history, the list has prevailed over and over again. it is by no means merely an expression of primitive cultures. a very clear image of the universe existed in the middle ages, and there were lists. a new worldview based on astronomy predominated in the renaissance and the baroque era. and there were lists. and the list is certainly prevalent in the postmodern age. it has an irresistible magic. β¦ we like lists because we don ' t want to die. here is much more. make sure you read the quotation under the photo ; i don ' t want to reproduce it on a family blog. i wonder if this interview was translated from some other language, given the difference between " lists " and " enumeration. " here is an important mr post : jeffrey lonsdale writes. i thank cardiff garcia for the pointer.
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- partial fractions [ 01 / 29 / 1998 ] how do i express 3 / 1 - ( x ^ 3 ) in partial fractions? - pascal ' s triangle pattern [ 04 / 22 / 1999 ] what pattern does multiplying each entry by 1, 2, 3, 4, 5... in order, and adding the products yield? - perfect square : solving two equations [ 6 / 14 / 1996 ] x ^ 2 + 5 is a perfect square, and x ^ 2 - 5 is a perfect square. - perimeter equals area in a triangle [ 4 / 2 / 1996 ] when will the area and perimeter of a right triangle be numerically - picture frame, triangle measurements [ 5 / 20 / 1996 ] my teacher gave us ten questions to answer and i could do all except two : 1 ) a framed rectangular picture is 35cm long and 25cm wide... 2 ) the base of a triangle is 9cm more than the perpendicular height... - plus or minus sign [ 03 / 08 / 2002 ] what does this equation mean : y = + - k? the - sign is directly under the - point equidistant from 3 other points [ 04 / 11 / 1999 ] how do you find a point that is equidistant from three other points? - point on a line [ 03 / 23 / 2001 ] can you please tell me a formula to find if a point exists on a line? both are in x, y form. - polynomial brain - twisters [ 12 / 4 / 1995 ] i ' m stumped on some similar polynomial problems... - polynomial degrees and definition of a field [ 03 / 02 / 1998 ] the degree of polynomials added together, and definition of a field. - polynomial factoring rules [ 04 / 02 / 1997 ] how do i apply the polynomial factoring rules to t ^ 21 + 1 and 25y ^ 2 - 144 = - polynomial problem [ 3 / 11 / 1995 ] a remainder of 9 results when the polynomial p ( x ) is divided by x - 2, a remainder of - 3 when p ( x ) is divided by x + 2, and a remainder of 3 when divided by x - 1. find the remainder when p ( x ) is divided by ( x - 2 ) ( x + 2 ) ( x - - population and percentage [ 03 / 07 / 1999 ] given population data, find the number of women in two different years. - positive unit fractions [ 10 / 02 / 2002 ] find five
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- 2 ) ( x + 2 ) ( x - - population and percentage [ 03 / 07 / 1999 ] given population data, find the number of women in two different years. - positive unit fractions [ 10 / 02 / 2002 ] find five different positive unit fractions whose sum is 1. ( a unit fraction is a fraction whose numerator is 1. all denominators must also be natural numbers. ) - precedence of unary operators [ 09 / 01 / 99 ] the pemdas rule for order of operations ignores unary operators. can you explain the proper precedence for them, and give an example showing how not knowing the rule can cause an incorrect result? - preparing for an algebra test [ 11 / 1 / 1995 ] a 9th grade math student asks for help preparing for final exams. what is the difference between the terms : solve and simplify? how do you find the gradient in a graph? - prize money [ 09 / 04 / 1997 ] if first prize wins $ 1, 000 out of $ 6, 000 and twentieth prize wins $ 100, how much money do second through nineteenth place win? is this a - probability of a function having complex roots [ 05 / 11 / 2000 ] what is the probability that the function f ( x ) = x ^ 2 + px + q = 0 will have complex roots when p and q lie between 0 and 1?... when p and q lie between 0 and 5?... when p and q are greater than 0?
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subdomain_quantum_computing
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welcome to medlibrary. org. for best results, we recommend beginning with the navigation links at the top of the page, which can guide you through our collection of over 14, 000 medication labels and package inserts. for additional information on other topics which are not covered by our database of medications, just enter your topic in the search box below : chromatography [ | krΙΚmΙ | tΙgrΙfi ] ( from greek ΟΟΟΞΌΞ± chroma " color " and Ξ³ΟΞ±ΟΡιν graphein " to write " ) is the collective term for a set of laboratory techniques for the separation of mixtures. the mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. the various constituents of the mixture travel at different speeds, causing them to separate. the separation is based on differential partitioning between the mobile and stationary phases. subtle differences in a compound ' s partition coefficient result in differential retention on the stationary phase and thus changing the separation. chromatography may be preparative or analytical. the purpose of preparative chromatography is to separate the components of a mixture for more advanced use ( and is thus a form of purification ). analytical chromatography is done normally with smaller amounts of material and is for measuring the relative proportions of analytes in a mixture. the two are not mutually exclusive. chromatography, literally " color writing ", was first employed by russian - italian scientist mikhail tsvet in 1900. he continued to work with chromatography in the first decade of the 20th century, primarily for the separation of plant pigments such as chlorophyll, carotenes, and xanthophylls. since these components have different colors ( green, orange, and yellow, respectively ) they gave the technique its name. new types of chromatography developed during the 1930s and 1940s made the technique useful for many separation processes. chromatography technique developed substantially as a result of the work of archer john porter martin and richard laurence millington synge during the 1940s and 1950s. they established the principles and basic techniques of partition chromatography, and their work encouraged the rapid development of several chromatographic methods : paper chromatography, gas chromatography, and what would become known as high performance liquid chromatography. since then, the technology has advanced rapidly. researchers found that the main principles
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development of several chromatographic methods : paper chromatography, gas chromatography, and what would become known as high performance liquid chromatography. since then, the technology has advanced rapidly. researchers found that the main principles of tsvet ' s chromatography could be applied in many different ways, resulting in the different varieties of chromatography described below. advances are continually improving the technical performance of chromatography, allowing the separation of increasingly similar molecules. chromatography terms - the analyte is the substance to be separated during chromatography. - analytical chromatography is used to determine the existence and possibly also the concentration of analyte ( s ) in a sample. - a bonded phase is a stationary phase that is covalently bonded to the support particles or to the inside wall of the column tubing. - a chromatogram is the visual output of the chromatograph. in the case of an optimal separation, different peaks or patterns on the chromatogram correspond to different components of the separated mixture. - plotted on the x - axis is the retention time and plotted on the y - axis a signal ( for example obtained by a spectrophotometer, mass spectrometer or a variety of other detectors ) corresponding to the response created by the analytes exiting the system. in the case of an optimal system the signal is proportional to the concentration of the specific analyte separated. - a chromatograph is equipment that enables a sophisticated separation e. g. gas chromatographic or liquid chromatographic separation. - chromatography is a physical method of separation that distributes components to separate between two phases, one stationary ( stationary phase ), while the other ( the mobile phase ) moves in a definite direction. - the eluate is the mobile phase leaving the column. - the eluent is the solvent that carries the analyte. - an eluotropic series is a list of solvents ranked according to their eluting power. - an immobilized phase is a stationary phase that is immobilized on the support particles, or on the inner wall of the column tubing. - the mobile phase is the phase that moves in a definite direction. it may be a liquid ( lc and capillary electrochromatography ( cec ) ), a gas ( gc ), or a supercritical fluid ( supercritical - fluid chromatography,
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a definite direction. it may be a liquid ( lc and capillary electrochromatography ( cec ) ), a gas ( gc ), or a supercritical fluid ( supercritical - fluid chromatography, sfc ). the mobile phase consists of the sample being separated / analyzed and the solvent that moves the sample through the column. in the case of hplc the mobile phase consists of a non - polar solvent ( s ) such as hexane in normal phase or polar solvents in reverse phase chromotagraphy and the sample being separated. the mobile phase moves through the chromatography column ( the stationary phase ) where the sample interacts with the stationary phase and is separated. - preparative chromatography is used to purify sufficient quantities of a substance for further use, rather than analysis. - the retention time is the characteristic time it takes for a particular analyte to pass through the system ( from the column inlet to the detector ) under set conditions. see also : kovats ' retention index - the sample is the matter analyzed in chromatography. it may consist of a single component or it may be a mixture of components. when the sample is treated in the course of an analysis, the phase or the phases containing the analytes of interest is / are referred to as the sample whereas everything out of interest separated from the sample before or in the course of the analysis is referred to as waste. - the solute refers to the sample components in partition chromatography. - the solvent refers to any substance capable of solubilizing another substance, and especially the liquid mobile phase in liquid chromatography. - the stationary phase is the substance fixed in place for the chromatography procedure. examples include the silica layer in thin layer chromatography chromatography is based on the concept of partition coefficient. any solute partitions between two immiscible solvents. when we make one solvent immobile ( by adsorption on a solid support matrix ) and another mobile it results in most common applications of chromatography. if matrix support is polar ( e. g. paper, silica etc. ) it is forward phase chromatography, and if it is non polar ( c - 18 ) it is reverse phase. techniques by chromatographic bed shape column chromatography column chromatography is a separation technique in which the stationary bed is within a tube.
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mixture travel different distances according to how strongly they interact with the stationary phase as compared to the mobile phase. the specific retention factor ( rf ) of each chemical can be used to aid in the identification of an unknown substance. paper chromatography paper chromatography is a technique that involves placing a small dot or line of sample solution onto a strip of chromatography paper. the paper is placed in a jar containing a shallow layer of solvent and sealed. as the solvent rises through the paper, it meets the sample mixture, which starts to travel up the paper with the solvent. this paper is made of cellulose, a polar substance, and the compounds within the mixture travel farther if they are non - polar. more polar substances bond with the cellulose paper more quickly, and therefore do not travel as far. thin layer chromatography thin layer chromatography ( tlc ) is a widely employed laboratory technique and is similar to paper chromatography. however, instead of using a stationary phase of paper, it involves a stationary phase of a thin layer of adsorbent like silica gel, alumina, or cellulose on a flat, inert substrate. compared to paper, it has the advantage of faster runs, better separations, and the choice between different adsorbents. for even better resolution and to allow for quantification, high - performance tlc can be used. displacement chromatography the basic principle of displacement chromatography is : a molecule with a high affinity for the chromatography matrix ( the displacer ) competes effectively for binding sites, and thus displace all molecules with lesser affinities. there are distinct differences between displacement and elution chromatography. in elution mode, substances typically emerge from a column in narrow, gaussian peaks. wide separation of peaks, preferably to baseline, is desired for maximum purification. the speed at which any component of a mixture travels down the column in elution mode depends on many factors. but for two substances to travel at different speeds, and thereby be resolved, there must be substantial differences in some interaction between the biomolecules and the chromatography matrix. operating parameters are adjusted to maximize the effect of this difference. in many cases, baseline separation of the peaks can be achieved only with gradient elution and low column loadings. thus, two drawbacks to elution mode chromatography, especially at the preparative
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maximize the effect of this difference. in many cases, baseline separation of the peaks can be achieved only with gradient elution and low column loadings. thus, two drawbacks to elution mode chromatography, especially at the preparative scale, are operational complexity, due to gradient solvent pumping, and low throughput, due to low column loadings. displacement chromatography has advantages over elution chromatography in that components are resolved into consecutive zones of pure substances rather than β peaks β. because the process takes advantage of the nonlinearity of the isotherms, a larger column feed can be separated on a given column with the purified components recovered at significantly higher concentrations. techniques by physical state of mobile phase gas chromatography gas chromatography ( gc ), also sometimes known as gas - liquid chromatography, ( glc ), is a separation technique in which the mobile phase is a gas. gas chromatography is always carried out in a column, which is typically " packed " or " capillary " ( see below ). gas chromatography is based on a partition equilibrium of analyte between a solid stationary phase ( often a liquid silicone - based material ) and a mobile gas ( most often helium ). the stationary phase is adhered to the inside of a small - diameter glass tube ( a capillary column ) or a solid matrix inside a larger metal tube ( a packed column ). it is widely used in analytical chemistry ; though the high temperatures used in gc make it unsuitable for high molecular weight biopolymers or proteins ( heat denatures them ), frequently encountered in biochemistry, it is well suited for use in the petrochemical, environmental monitoring and remediation, and industrial chemical fields. it is also used extensively in chemistry research. liquid chromatography liquid chromatography ( lc ) is a separation technique in which the mobile phase is a liquid. liquid chromatography can be carried out either in a column or a plane. present day liquid chromatography that generally utilizes very small packing particles and a relatively high pressure is referred to as high performance liquid chromatography ( hplc ). in hplc the sample is forced by a liquid at high pressure ( the mobile phase ) through a column that is packed with a stationary phase composed of irregularly or spherically shaped particles, a porous monolithic layer, or a porous membrane. hplc is historically divided into two
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a liquid at high pressure ( the mobile phase ) through a column that is packed with a stationary phase composed of irregularly or spherically shaped particles, a porous monolithic layer, or a porous membrane. hplc is historically divided into two different sub - classes based on the polarity of the mobile and stationary phases. methods in which the stationary phase is more polar than the mobile phase ( e. g., toluene as the mobile phase, silica as the stationary phase ) are termed normal phase liquid chromatography ( nplc ) and the opposite ( e. g., water - methanol mixture as the mobile phase and c18 = octadecylsilyl as the stationary phase ) is termed reversed phase liquid chromatography ( rplc ). ironically the " normal phase " has fewer applications and rplc is therefore used considerably more. specific techniques under this broad heading are listed below. affinity chromatography affinity chromatography is based on selective non - covalent interaction between an analyte and specific molecules. it is very specific, but not very robust. it is often used in biochemistry in the purification of proteins bound to tags. these fusion proteins are labeled with compounds such as his - tags, biotin or antigens, which bind to the stationary phase specifically. after purification, some of these tags are usually removed and the pure protein is obtained. affinity chromatography often utilizes a biomolecule ' s affinity for a metal ( zn, cu, fe, etc. ). columns are often manually prepared. traditional affinity columns are used as a preparative step to flush out unwanted biomolecules. however, hplc techniques exist that do utilize affinity chromatogaphy properties. immobilized metal affinity chromatography ( imac ) is useful to separate aforementioned molecules based on the relative affinity for the metal ( i. e. dionex imac ). often these columns can be loaded with different metals to create a column with a targeted affinity. supercritical fluid chromatography supercritical fluid chromatography is a separation technique in which the mobile phase is a fluid above and relatively close to its critical temperature and pressure. techniques by separation mechanism ion exchange chromatography ion exchange chromatography ( usually referred to as ion chromatography ) uses an ion exchange mechanism to separate analytes based on their respective charges. it is usually performed in columns but can also be useful in
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exchange chromatography ion exchange chromatography ( usually referred to as ion chromatography ) uses an ion exchange mechanism to separate analytes based on their respective charges. it is usually performed in columns but can also be useful in planar mode. ion exchange chromatography uses a charged stationary phase to separate charged compounds including anions, cations, amino acids, peptides, and proteins. in conventional methods the stationary phase is an ion exchange resin that carries charged functional groups that interact with oppositely charged groups of the compound to retain. ion exchange chromatography is commonly used to purify proteins using fplc. size - exclusion chromatography size - exclusion chromatography ( sec ) is also known as gel permeation chromatography ( gpc ) or gel filtration chromatography and separates molecules according to their size ( or more accurately according to their hydrodynamic diameter or hydrodynamic volume ). smaller molecules are able to enter the pores of the media and, therefore, molecules are trapped and removed from the flow of the mobile phase. the average residence time in the pores depends upon the effective size of the analyte molecules. however, molecules that are larger than the average pore size of the packing are excluded and thus suffer essentially no retention ; such species are the first to be eluted. it is generally a low - resolution chromatography technique and thus it is often reserved for the final, " polishing " step of a purification. it is also useful for determining the tertiary structure and quaternary structure of purified proteins, especially since it can be carried out under native solution conditions. expanded bed adsorption ( eba ) chromatographic separation expanded bed adsorption ( eba ) chromatographic separation captures a target protein from a crude feed stream when it passes through a chromatography column system containing adsorbent beads. with this technique the crude feedstock can be treated directly in the chromatographic column, avoiding the traditional clarification and pre - treatment steps. eba chromatographic separation is highly scalable, from laboratory - based 1 cm diameter columns to large production columns up to 2 meter in diameter. these columns can typically handle feed stock throughput of more than 1, 000, 000 liter per day with a production capacity of 1000 mt protein per year. special techniques reversed - phase chromatography reversed - phase chromatography ( r
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. these columns can typically handle feed stock throughput of more than 1, 000, 000 liter per day with a production capacity of 1000 mt protein per year. special techniques reversed - phase chromatography reversed - phase chromatography ( rpc ) is any liquid chromatography procedure in which the mobile phase is significantly more polar than the stationary phase. it is so named because in normal - phase liquid chromatography, the mobile phase is significantly less polar than the stationary phase. hydrophobic molecules in the mobile phase tend to adsorb to the relatively hydrophobic stationary phase. hydrophilic molecules in the mobile phase will tend to elute first. two - dimensional chromatography in some cases, the chemistry within a given column can be insufficient to separate some analytes. it is possible to direct a series of unresolved peaks onto a second column with different physico - chemical ( chemical classification ) properties. since the mechanism of retention on this new solid support is different from the first dimensional separation, it can be possible to separate compounds that are indistinguishable by one - dimensional chromatography. the sample is spotted at one corner of a square plate, developed, air - dried, then rotated by 90Β° and usually redeveloped in a second solvent system. simulated moving - bed chromatography pyrolysis gas chromatography pyrolysis gas chromatography mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. pyrolysis is the thermal decomposition of materials in an inert atmosphere or a vacuum. the sample is put into direct contact with a platinum wire, or placed in a quartz sample tube, and rapidly heated to 600 β 1000 Β°c. depending on the application even higher temperatures are used. three different heating techniques are used in actual pyrolyzers : isothermal furnace, inductive heating ( curie point filament ), and resistive heating using platinum filaments. large molecules cleave at their weakest points and produce smaller, more volatile fragments. these fragments can be separated by gas chromatography. pyrolysis gc chromatograms are typically complex because a wide range of different decomposition products is formed. the data can either be used as fingerprint to prove material identity or the gc / ms data is used to identify individual
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pyrolysis gc chromatograms are typically complex because a wide range of different decomposition products is formed. the data can either be used as fingerprint to prove material identity or the gc / ms data is used to identify individual fragments to obtain structural information. to increase the volatility of polar fragments, various methylating reagents can be added to a sample before pyrolysis. besides the usage of dedicated pyrolyzers, pyrolysis gc of solid and liquid samples can be performed directly inside programmable temperature vaporizer ( ptv ) injectors that provide quick heating ( up to 30 Β°c / s ) and high maximum temperatures of 600 β 650 Β°c. this is sufficient for some pyrolysis applications. the main advantage is that no dedicated instrument has to be purchased and pyrolysis can be performed as part of routine gc analysis. in this case quartz gc inlet liners have to be used. quantitative data can be acquired, and good results of derivatization inside the ptv injector are published as well. fast protein liquid chromatography fast protein liquid chromatography ( fplc ) is a term applied to several chromatography techniques which are used to purify proteins. many of these techniques are identical to those carried out under high performance liquid chromatography, however use of fplc techniques are typically for preparing large scale batches of a purified product. countercurrent chromatography countercurrent chromatography ( ccc ) is a type of liquid - liquid chromatography, where both the stationary and mobile phases are liquids. the operating principle of ccc equipment requires a column consisting of an open tube coiled around a bobbin. the bobbin is rotated in a double - axis gyratory motion ( a cardioid ), which causes a variable gravity ( g ) field to act on the column during each rotation. this motion causes the column to see one partitioning step per revolution and components of the sample separate in the column due to their partitioning coefficient between the two immiscible liquid phases used. there are many types of ccc available today. these include hsccc ( high speed ccc ) and hpccc ( high performance ccc ). hpccc is the latest and best performing version of the instrumentation available currently. chiral chromatography chiral chromatography involves the separation of stereoisomers.
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ccc ) and hpccc ( high performance ccc ). hpccc is the latest and best performing version of the instrumentation available currently. chiral chromatography chiral chromatography involves the separation of stereoisomers. in the case of enantiomers, these have no chemical or physical differences apart from being three - dimensional mirror images. conventional chromatography or other separation processes are incapable of separating them. to enable chiral separations to take place, either the mobile phase or the stationary phase must themselves be made chiral, giving differing affinities between the analytes. chiral chromatography hplc columns ( with a chiral stationary phase ) in both normal and reversed phase are commercially available. see also - iupac nomenclature for chromatography iupac recommendations 1993, pure & appl. chem., vol. 65, no. 4, pp. 819 β 872, 1993. - still, w. c. ; kahn, m. ; mitra, a. j. org. chem. 1978, 43 ( 14 ), 2923 β 2925. doi : 10. 1021 / jo00408a041 - laurence m. harwood, christopher j. moody ( 13 june 1989 ). experimental organic chemistry : principles and practice ( illustrated ed. ). wileyblackwell. pp. 180 β 185. isbn 978 - 0 - 632 - 02017 - 1 [ amazon - us | amazon - uk ]. - christian b. anfinsen, john tileston edsall, frederic middlebrook richards advances in protein chemistry. science 1976, 6 - 7. - displacement chromatography 101. sachem, inc. austin, tx 78737 - pascal bailon, george k. ehrlich, wen - jian fung and wolfgang berthold, an overview of affinity chromatography, humana press, 2000. isbn 978 - 0 - 89603 - 694 - 9 [ amazon - us | amazon - uk ], isbn 978 - 1 - 60327 - 261 - 2 [ amazon - us | amazon - uk ]. - iupac nomenclature for chromatography - chromedia on line database and community for chromatography practitioners ( paid subscription required ) - library 4 science : chrom - ed series - overlapping peaks program β learning by simulations - chromatography videos β mit ocw β digital lab techniques manual - chromato
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other proposed treatments it is one of the cardinal principles of natural medicine that treatment should aim not only to treat illness but also to enhance wellness. according to this ideal, a proper course of treatment should improve your sense of general well - being, enhance your immunity to illness, raise your physical stamina, and increase mental alertness, as well as resolve the specific condition you took it for. unfortunately, while there can be little doubt that this is a laudable goal, it is easier to laud it than to achieve it. conventional medicine tends to focus on treating diseases rather than increasing wellness, not as a matter of philosophical principle, but because it is easier to accomplish. probably the strongest force affecting wellness is genetics. beyond that, common sense steps endorsed by all physicians include increasing exercise, reducing stress, improving diet, getting enough sleep, and living a life of moderation without bad habits, such as smoking or overeating. beyond this, however, it is difficult to make strong affirmations, and the optimum forms of diet and exercise and other aspects of lifestyle remain unclear. in fact, they may always remain unclear, as it is impossible to perform double - blind, placebo - controlled studies on most lifestyle habits. ( for information on why such studies are irreplaceable see " why does this database depend on double - blind studies? " ) principal proposed natural treatments in order to function at our best, we need good nutrition. however, the modern diet often fails to provide people with sufficient amounts of all the necessary nutrients. for this reason, use of a multivitamin / multimineral supplement might be expected to enhance overall health and well - being, and preliminary double - blind trials generally support this view. for more information, see the article on general nutritional support. the herb panax ginseng has an ancient reputation as a healthful β tonic. β according to a more modern concept developed in the former ussr, ginseng functions as an β adaptogen. β this term is defined as follows : an adaptogen helps the body adapt to stresses of various kinds, whether heat, cold, exertion, trauma, sleep deprivation, toxic exposure, radiation, infection, or psychologic stress. in addition, an adaptogen causes no side effects, is effective in treating a wide variety of illnesses, and helps return an organism toward balance no matter what may have gone wrong. from a modern scientific perspective, it is not truly clear that such things as adaptogens actually exist. however, there is some
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, attend a full schedule of groups and individual therapies at our clinical campus [ near the residential complex ], attend local community support groups in the evenings, and visit with our physicians and clinical staff regularly throughout their stay. in effect, the experience is one of providing a supportive and structured setting without the restrictive elements of a " hospital " or institutional facility. a key element in providing the support necessary to begin recovery is remaining in the company of other participants during the initial phase of the treatment. this provides both a form of supervision and a deterrent from the behavior often associated with binge eating : namely eating in isolation or alone. secondly, milestones approaches treatment from a more " holistic " perspective. doing so is best described by the acronym " serf " - spirituality, exercise, rest, and food plan. spirituality need not equate with any religious or spiritual beliefs imposed on or by anyone. in fact, spirituality at milestones simply is left up to the individual to cultivate with his or her own working definition. for most, it is a belief in a " higher power " and still for others it may be a return to some of their original religious beliefs. for everyone, it is an individual journey. exercise is individualized and represents collaboration between the resident and clinical team. it is meant to be in the service of restoring and maintaining a healthy body rather than an " intensive " means of controlling body weight. rest is simply about finding the correct balance in recovery between work and play and narrowing the gap between an " all or none ", " feast or famine " approach to daily living. the food plan suggested by milestones is a blend of structured eating and a combination of healthy, whole foods that are bought and prepared by participants with the guidance and supervision of our dietitian and ancillary staff. in brief participants select their own preferences within the guidelines of their individual food plans. the guidelines require participants to abstain from " junk foods " and eliminate most highly processed [ sugar and flour laden ] food products as well as weigh and measure portions per their food plan while in residence. it is important to mention most participants who seek treatment for most eating disorders may have a tendency to focus on " trading in the binging and / or " purging " to become better at restricting or " losing weight " and as such, it is important to understand the predisposition to replace one form of an eating disorder for another. acknowledging this is helpful to maintaining the prescribed treatment plan both during and after the residential treatment experience.
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subdomain_quantum_field_theory
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HuggingFaceFW/fineweb-edu
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2025-12-19T07:35:33.204889
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deep - space communication improved with electromagnetic radiation antenna - robert c. dye - technology transfer - ( 505 ) 667 - 3404 electromagnetic radiation antenna has potential for deep - space communication - directed energy - long - range communications - medicine ( oncology ) - radar imaging applications are countermeasure - resistant - communications can be spatially - encrypted - 4 - dimensional volumes of energy can be aimed at a single space - time point for directed energy applications - nonspherical decay of the cusp enables low - power communications and propagation over great distances los alamos national laboratory ( lanl ) researchers have developed the lightslinger, a completely new type of antenna that produces tightly - focused packets of electromagnetic radiation fundamentally different from the emissions of conventional transmitters. the device has potential applications in radar, directed - energy ( non - kinetic kill ), secure communications, ultra - long - range communications ( e. g., deep - space ), medicine ( oncology ) and astrophysics. the lightslinger functions by producing a moving polarization pattern in a ring of alumina. by careful timing of voltages applied to electrodes that surround the alumina, the polarization pattern can be made to move superluminally, i. e., faster than the speed of light in a vacuum. nobel laureate vitaly ginzberg showed both that such superluminal polarization patterns do not violate the principles of special relativity and that they emit electromagnetic radiation. once a source travels faster than the waves that it emits, it can make contributions at multiple retarded times to a signal received instantaneously at a distance. this effect is already well known in acoustics ; when a supersonic airplane accelerates through the speed of sound, a violent β sonic boom β is heard many miles away, even if the airplane itself is rather quiet. the lightslinger enables the same thing to be done with electromagnetic radiation ; i. e., a relatively low - power source can make an β electromagnetic boom β, an intense concentration of radiowaves at a great distance. the β electromagnetic boom β is due to temporal focusing, that is, focusing in the time domain. because of this effect, part of the emitted radiation possesses an intensity that decays with distance r as 1 / r rather than as the conventional inverse square law, 1 / r2. these nonspherically - decaying wavepackets represent a game - changing technology in the applications of electromagnetic radiation. development stage : working prototype patent status : patent pending
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subdomain_quantum_optics
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2025-12-19T07:35:33.223003
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jim lake and maria rivera, at the university of california - los angeles ( ucla ), report their finding in the sept. 9 issue of the journal nature. scientists refer to both bacteria and archaea as " prokaryotes " - - a cell type that has no distinct nucleus to contain the genetic material, dna, and few other specialized components. more - complex cells, known as " eukaryotes, " contain a well - defined nucleus as well as compartmentalized " organelles " that carry out metabolism and transport molecules throughout the cell. yeast cells are some of the most - primitive eukaryotes, whereas the highly specialized cells of human beings and other mammals are among the most complex. " a major unsolved question in biology has been where eukaryotes came from, where we came from, " lake said. " the answer is that we have two parents, and we now know who those parents were. " further, he added, the results provide a new picture of evolutionary pathways. " at least 2 billion years ago, ancestors of these two diverse prokaryotic groups fused their genomes to form the first eukaryote, and in the processes two different branches of the tree of life were fused to form the ring of life, " lake said. the work is part of an effort supported by the national science foundation - - the federal agency that supports research and education across all disciplines of science and engineering - - to re - examine historical schemes for classifying earth ' s living creatures, a process that was once based on easily observable traits. microbes, plants or animals wer contact : leslie fink national science foundation
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subdomain_quantum_gravity
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2025-12-19T07:35:33.240495
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refraction and acceleration name : christopher s. why is it that when light travels from a more dense to a less dense medium, its speed is higher? i ' ve read answers to this question in your archives but, sadly, still don ' t get it. one answer ( jasjeet s bagla ) says that we must not ask the question because light is massless, hence questions of acceleration don ' t make sense. it does, however, seem to be ok to talk about different speeds of light. if you start at one speed and end at a higher one, why is one not allowed to talk about acceleration? bagla goes on to say that it depends on how the em fields behave in a given medium. it begs the question : what is it about, say, perspex and air that makes light accelerate, oops, travel at different speeds? if you ' re dealing with the same ray of light, one is forced to speak of acceleration, no? what other explanation is there for final velocity > initial velocity? arthur smith mentioned a very small " evanescent " component that travels ahead at c. where can i learn more about this? sorry for the long question. i understand that f = ma and if there is no m, you cannot talk about a, but, again, you have one velocity higher than another for the same thing. i need to know more than " that ' s just the way em fields are! " an explanation that satisfies me relates to travel through an interactive medium. when light interacts with an atom, the photon of light is absorbed and then emitted. for a moment, the energy of the light is within the atom. this causes a slight delay. light travels at the standard speed of light until interacting with another atom. it is absorbed and emitted, causing another slight delay. the average effect is taking more time to travel a meter through glass than through air. this works like a slower speed. an individual photon does not actually slow down. it gets delayed repeatedly by the atoms of the medium. a more dense medium has more atoms per meter to dr. ken mellendorf illinois central college congratulations! on not being willing to accept " that is just the way em fields are! " the answer to your inquiry is not all that simple ( my opinion ), but i won ' t try to do so in the limited space allowed here, not to say my own limitations of knowledge. like so many " simple " physics questions, i find the most lucid
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subdomain_quantum_optics
| 0.599143
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HuggingFaceFW/fineweb-edu
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<urn:uuid:d2b35c16-35c7-477e-80c7-8dded3739ec4>
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2025-12-19T07:35:33.260057
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is not all that simple ( my opinion ), but i won ' t try to do so in the limited space allowed here, not to say my own limitations of knowledge. like so many " simple " physics questions, i find the most lucid, but accurate, explanation in richard feynman ' s, " lectures on physics " which most libraries will have. volume i, chapter 31 - 1 through 31 - 6, which describes refraction, dispersion, diffraction. the " answer " has to do with how matter alters the electric field of incident radiation, but i won ' t pretend to be able to do a better job than feynman. the answer is that you are not dealing with the same ray of light. in vacuum a photon just keeps going at the speed of light. in a medium, however, it interacts with the atoms, often being absorbed while bumping an atomic or molecular motion into a higher energy state. the excited atom / molecule then can jump to a lower energy state, emitting a photon while doing so. this can obviously make light appear to travel slower in a in detail, it is a very complicated question, requiring at least a graduate course in electromagnetism to begin to understand. why, for example do the emitted photons tend to travel in the same direction? best, richard j. plano click here to return to the physics archives update : june 2012
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subdomain_quantum_optics
| 0.626201
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HuggingFaceFW/fineweb-edu
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<urn:uuid:d2b35c16-35c7-477e-80c7-8dded3739ec4>
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2025-12-19T07:35:33.261087
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attempts to relay mail by issuing a predefined combination of smtp commands. the goal of this script is to tell if a smtp server is vulnerable to mail relaying. an smtp server that works as an open relay, is a email server that does not verify if the user is authorised to send email from the specified email address. therefore, users would be able to send email originating from any third - party email address that they want. the checks are done based in combinations of mail from and rcpt to commands. the list is hardcoded in the source file. the script will output all the working combinations that the server allows if nmap is in verbose mode otherwise the script will print the number of successful tests. the script will not output if the server requires authentication. if debug is enabled and an error occurrs while testing the target host, the error will be printed with the list of any combinations that were found prior to the error. use this to change the ip address to be used ( default is the target ip address ) define the destination email address to be used ( without the domain, default is relaytest ) or smtp - open - relay. domain define the domain to be used in the anti - spam tests and ehlo command ( default is nmap. scanme. org ) define the source email address to be used ( without the domain, default is antispam ) smbdomain, smbhash, smbnoguest, smbpassword, smbtype, smbusernamesee the documentation for the smbauth library. nmap - - script smtp - open - relay. nse [ - - script - args smtp - open - relay. domain = < domain >, smtp - open - relay. ip = < address >,... ] - p 25, 465, 587 < host > host script results : | smtp - open - relay : server is an open relay ( 1 / 16 tests ) | _ mail from : < email @ example. com > - > rcpt to : < firstname. lastname @ example. org > author : arturo ' buanzo ' busleiman license : same as nmap - - see http : / / nmap. org / book / man - legal. html
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subdomain_quantum_cryptography
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HuggingFaceFW/fineweb-edu
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<urn:uuid:2fc62870-a21f-42bb-90f1-0b5d5c8d75a5>
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2025-12-19T07:35:33.263774
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topics covered : ideal solutions instructor / speaker : moungi bawendi, keith nelson the following content is provided under a creative commons license. your support will help mit opencourseware continue to offer high quality educational resources for free. to make a donation or view additional materials from hundreds of mit courses, visit mit opencourseware at ocw. mit. edu. professor : so. in the meantime, you ' ve started looking at two phase equilibrium. so now we ' re starting to look at mixtures. and so now we have more than one constituent. and we have more than one phase present. right? so you ' ve started to look at things that look like this, where you ' ve got, let ' s say, two components. both in the gas phase. and now to try to figure out what the phase equilibria look like. of course it ' s now a little bit more complicated than what you went through before, where you can get pressure temperature phase diagrams with just a single component. now we want to worry about what ' s the composition. of each of the components. in each of the phases. and what ' s the temperature and the pressure. total and partial pressures and all of that. so you can really figure out everything about both phases. and there are all sorts of important reasons to do that, obviously lots of chemistry happens in liquid mixtures. some in gas mixtures. some where they ' re in equilibrium. all sorts of chemical processes. distillation, for example, takes advantage of the properties of liquid and gas mixtures. where one of them might be richer, will be richer, and the more volatile of the components. that can be used as a basis for purification. you mix ethanol and water together so you ' ve got a liquid with a certain composition of each. the gas is going to be richer and the more volatile of the two, the ethanol. so in a distillation, where you put things up in the gas, more of the ethanol comes up. you could then collect that gas, right? and re - condense it, and make a new liquid. which is much richer in ethanol than the original liquid was. then you could make, then you could put some of them up into the gas phase. where it will be still richer in ethanol. and then you could collect that and repeat the process. so the point is that properties of liquid gas, two - component or multi - component mixtures like this can
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subdomain_quantum_thermodynamics
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
| 0
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2025-12-19T07:35:33.303659
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of them up into the gas phase. where it will be still richer in ethanol. and then you could collect that and repeat the process. so the point is that properties of liquid gas, two - component or multi - component mixtures like this can be exploited. basically, the different volatilities of the different components can be exploited for things like purification. also if you want to calculate chemical equilibria in the liquid and gas phase, of course, now you ' ve seen chemical equilibrium, so the amount of reaction depends on the composition. so of course if you want reactions to go, then this also can be exploited by looking at which phase might be richer in one reactant or another. and thereby pushing the equilibrium toward one direction or the other. ok. so. we ' ve got some total temperature and pressure. and we have compositions. so in the gas phase, we ' ve got mole fractions ya and yb. in the liquid phase we ' ve got mole fractions xa and xb. so that ' s our system. one of the things that you established last time is that, so there are the total number of variables including the temperature and the pressure. and let ' s say the mole fraction of a in each of the liquid and gas phases, right? but then there are constraints. because the chemical potentials have to be equal, right? chemical potential of a has to be equal in the liquid and gas. same with b. those two constraints reduce the number of independent variables. so there ' ll be two in this case rather than four independent variables. if you control those, then everything else will follow. what that means is if you ' ve got a, if you control, if you fix the temperature and the total pressure, everything else should be determinable. no more free variables. and then, what you saw is that in simple or ideal liquid mixtures, a result called raoult ' s law would hold. which just says that the partial pressure of a is equal to the mole fraction of a in the liquid times the pressure of pure a over the liquid. and so what this gives you is a diagram that looks like this. if we plot this versus xb, this is mole fraction of b in the liquid going from zero to one. then we could construct a diagram of this sort. so this is the total pressure of a and b. the partial pressures are given by these lines. so this is our pa star and pb star. the pressures over
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subdomain_quantum_thermodynamics
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
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2025-12-19T07:35:33.304562
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going from zero to one. then we could construct a diagram of this sort. so this is the total pressure of a and b. the partial pressures are given by these lines. so this is our pa star and pb star. the pressures over the pure liquid a and b at the limits of mole fraction of b being zero and one. so in this situation, for example, a is the more volatile of the components. so it ' s partial pressure over its pure liquid. at this temperature. is higher than the partial pressure of b over its pure liquid. a would be the ethanol, for example and b the water in that mixture. ok. then you started looking at both the gas and the liquid phase in the same diagram. so this is the mole fraction of the liquid. if you look and see, well, ok now we should be able to determine the mole fraction in the gas as well. again, if we note total temperature and pressure, everything else must follow. and so, you saw this worked out. relation between p and ya, for example. the result was p is pa star times pb star over pa star plus pb star minus pa star times ya. and the point here is that unlike this case, where you have a linear relationship, the relationship between the pressure and the liquid mole fraction isn ' t linear. we can still plot it, of course. so if we do that, then we end up with a diagram that looks like the following. now i ' m going to keep both mole fractions, xb and yb, i ' ve got some total pressure. i still have my linear relationship. and then i have a non - linear relationship between the pressure and the mole fraction in the gas phase. so let ' s just fill this in. here is pa star still. here ' s pb star. of course, at the limits they ' re still, both mole fractions they ' re zero and one. ok. i believe this is this is where you ended up at the end of the last lecture. but it ' s probably not so clear exactly how you read something like this. and use it. it ' s extremely useful. you just have to kind of learn how to follow what happens in a diagram like this. and that ' s what i want to spend some of today doing. is just, walking through what ' s happening physically, with a container with a mixture of the two. and how does that correspond to what gets read off the diagram under different
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subdomain_quantum_optics
| 0.581275
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
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2025-12-19T07:35:33.305453
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. and that ' s what i want to spend some of today doing. is just, walking through what ' s happening physically, with a container with a mixture of the two. and how does that correspond to what gets read off the diagram under different conditions. so. let ' s just start somewhere on a phase diagram like this. let ' s start up here at some point one, so we ' re in the pure - well, not pure, you ' re in the all liquid phase. it ' s still a mixture. it ' s not a pure substance. pa star, pb star. there ' s the gas phase. so, if we start at one, and now there ' s some total pressure. and now we ' re going to reduce it. what happens? we start with a pure - with an all - liquid mixture. no gas. and now we ' re going to bring down the pressure. allowing some of the liquid to go up into the gas phase. so, we can do that. and once we reach point two, then we find a coexistence curve. now the liquid and gas are going to coexist. so this is the liquid phase. and that means that this must be xb. and it ' s xb at one, but it ' s also xb at two, and i want to emphasize that. so let ' s put our pressure for two. and if we go over here, this is telling us about the mole fraction in the gas phase. that ' s what these curves are, remember. so this is the one that ' s showing us the mole fraction in the liquid phase. this nonlinear one in the gas phase. so that means just reading off it, this is xb, that ' s the liquid mole fraction. here ' s yb. the gas mole fraction. they ' re not the same, right, because of course the components have different volatility. a ' s more volatile. so that means that the mole fraction of b in the liquid phase is higher than the mole fraction of b in the gas phase. because a is the more volatile component. so more, relatively more, of a, the mole fraction of a is going to be higher up in the gas phase. which means the mole fraction of b is lower in the gas phase. so, yb less than xb if a is more volatile. ok, so now what ' s happening physically? well, we started at a point where we only had the
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subdomain_quantum_field_theory
| 0.596711
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
| 3
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2025-12-19T07:35:33.306318
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which means the mole fraction of b is lower in the gas phase. so, yb less than xb if a is more volatile. ok, so now what ' s happening physically? well, we started at a point where we only had the liquid present. so at our initial pressure, we just have all liquid. there ' s some xb at one. that ' s all there is, there isn ' t any gas yet. now, what happened here? well, now we lowered the pressure. so you could imagine, well, we made the box bigger. now, if the liquid was under pressure, being squeezed by the box, right then you could make the box a little bit bigger. and there ' s still no gas. that ' s moving down like this. but then you get to a point where there ' s just barely any pressure on top of the liquid. and then you keep expanding the box. now some gas is going to form. so now we ' re going to go to our case two. we ' ve got a bigger box. and now, right around where this was, this is going to be liquid. and there ' s gas up here. so up here is yb at pressure two. here ' s xb at pressure two. liquid and gas. so that ' s where we are at point two here. now, what happens if we keep going? let ' s lower the pressure some more. well, we can lower it and do this. but really if we want to see what ' s happening in each of the phases, we have to stay on the coexistence curves. those are what tell us what the pressures are. what the partial pressure are going to be in each of the phases. in each of the two, in the liquid and the gas phases. so let ' s say we lower the pressure a little more. what ' s going to happen is, then we ' ll end up somewhere over here. in the liquid, and that ' ll correspond to something over here in the gas. so here ' s three. so now we ' re going to have, that ' s going to be xb at pressure three. and over here is going to be yb at pressure three. and all we ' ve done, of course, is we ' ve just expanded this further. so now we ' ve got a still taller box. and the liquid is going to be a little lower because some of it has evaporated, formed the gas phase
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subdomain_quantum_field_theory
| 0.572187
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
| 4
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2025-12-19T07:35:33.307277
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' ve done, of course, is we ' ve just expanded this further. so now we ' ve got a still taller box. and the liquid is going to be a little lower because some of it has evaporated, formed the gas phase. so here ' s xb at three. here ' s yb at three, here ' s our gas phase. now we could decrease even further. and this is the sort of thing that you maybe can ' t do in real life. but i can do on a blackboard. i ' m going to give myself more room on this curve, to finish this illustration. there. beautiful. so now we can lower a little bit further, and what i want to illustrate is, if we keep going down, eventually we get to a pressure where now if we look over in the gas phase, we ' re at the same pressure, mole fraction that we had originally in the liquid phase. so let ' s make four even lower pressure. what does that mean? what it means is, we ' re running out of liquid. so what ' s supposed to happen is a is the more volatile component. so as we start opening up some room for gas to form, you get more of a in the gas phase. but of course, and the liquid is richer in b. but of course, eventually you run out of liquid. you make the box pretty big, and you run out, or you have the very last drop of liquid. so what ' s the mole fraction of b in the gas phase? it has to be the same as what it started in in the liquid phase. because after all the total number of moles of a and b hasn ' t changed any. so if you take them all from the liquid and put them all up into the gas phase, it must be the same. so yb of four. once you just have the last drop. so then yb of four is basically equal to xb of one. because everything ' s now up in the gas phase. so in principle, there ' s still a tiny, tiny bit of xb at pressure four. well, we could keep lowering the pressure. we could make the box a little bigger. then the very last of the liquid is going to be gone. and what ' ll happen then is, we ' re all here. there ' s no more liquid. we ' re not going down on the coexistence curve any more. we don ' t have a liquid gas
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subdomain_quantum_field_theory
| 0.585363
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
| 5
| 0.5
|
2025-12-19T07:35:33.308140
|
going to be gone. and what ' ll happen then is, we ' re all here. there ' s no more liquid. we ' re not going down on the coexistence curve any more. we don ' t have a liquid gas coexistence any more. we just have a gas phase. of course, we can continue to lower the pressure. and then what we ' re doing is just going down here. so there ' s five. and five is the same as this only bigger. and so forth. ok, any questions about how this works? it ' s really important to just gain facility in reading these things and seeing, ok, what is it that this is telling you. and you can see it ' s not complicated to do it, but it takes a little bit of practice. ok. now, of course, we could do exactly the same thing starting from the gas phase. and raising the pressure. and although you may anticipate that it ' s kind of pedantic, i really do want to illustrate something by it. so let me just imagine that we ' re going to do that. let ' s start all in the gas phase. up here ' s the liquid. pa star, pb star. and now let ' s start somewhere here. so we ' re down somewhere in the gas phase with some composition. so it ' s the same story, except now we ' re starting here. it ' s all gas. and we ' re going to start squeezing. we ' re increasing the pressure. and eventually here ' s one, will reach two, so of course here ' s our yb. we started with all gas, no liquid. so this is yb of one. it ' s the same as yb of two, i ' m just raising the pressure enough to just reach the coexistence curve. and of course, out here tells us xb of two, right? so what is it saying? we ' ve squeezed and started to form some liquid. and the liquid is richer in component b. maybe it ' s ethanol water again. and we squeeze, and now we ' ve got more water in the liquid phase than in the gas phase. because water ' s the less volatile component. it ' s what ' s going to condense first. so the liquid is rich in the less volatile of the components. now, obviously, we can continue in doing exactly the reverse of what i showed you. but all i want to
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subdomain_quantum_gravity
| 0.592963
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
| 6
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2025-12-19T07:35:33.309053
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component. it ' s what ' s going to condense first. so the liquid is rich in the less volatile of the components. now, obviously, we can continue in doing exactly the reverse of what i showed you. but all i want to really illustrate is, this is a strategy for purification of the less volatile component. once you ' ve done this, well now you ' ve got some liquid. now you could collect that liquid in a separate vessel. so let ' s collect the liquid mixture with xb of two. so it ' s got some mole fraction of b. so we ' ve purified that. but now we ' re going to start, we ' ve got pure liquid. now let ' s make the vessel big. so it all goes into the gas phase. then lower p. all gas. so we start with yb of three, which equals xb of two. in other words, it ' s the same mole fraction. so let ' s reconstruct that. so here ' s p of two. and now we ' re going to go to some new pressure. and the point is, now we ' re going to start, since the mole fraction in the gas phase that we ' re starting from is the same number as this was. so it ' s around here somewhere. that ' s yb of three equals xb of two. and we ' re down here. in other words, all we ' ve done is make the container big enough so the pressure ' s low and it ' s all in the gas phase. that ' s all we have, is the gas. but the composition is whatever the composition is that we extracted here from the liquid. so this xb, which is the liquid mole fraction, is now yb, the gas mole fraction. of course, the pressure is different. lower than it was before. great. now let ' s increase. so here ' s three. and now let ' s increase the pressure to four. and of course what happens, now we ' ve got coexistence. so here ' s liquid. here ' s gas. so, now we ' re over here again. there ' s xb at pressure four. pure still in component b. we can repeat the same procedure. collect it. all liquid, put it in a new vessel. expand it, lower the pressure, all goes back into the gas phase. do it all again. and the point is, what you ' re doing is walking along
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subdomain_quantum_thermodynamics
| 0.585909
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:246f9a12-fd35-40fa-8257-b07bf8d92857>
| 7
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2025-12-19T07:35:33.309901
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the same procedure. collect it. all liquid, put it in a new vessel. expand it, lower the pressure, all goes back into the gas phase. do it all again. and the point is, what you ' re doing is walking along here. here to here. then you start down here, and go from here to here. from here to here. and you can purify. now, of course, the optimal procedure, you have to think a little bit. because if you really do precisely what i said, you ' re going to have a mighty little bit of material each time you do that. so yes it ' ll be the little bit you ' ve gotten at the end is going to be really pure, but there ' s not a whole lot of it. because, remember, what we said is let ' s raise the pressure until we just start being on the coexistence curve. so we ' ve still got mostly gas. little bit of liquid. now, i could raise the pressure a bit higher. so that in the interest of having more of the liquid, when i do that, though, the liquid that i have at this higher pressure won ' t be as enriched as it was down here. now, i could still do this procedure. i could just do more of them. so it takes a little bit of judiciousness to figure out how to optimize that. in the end, though, you can continue to walk your way down through these coexistence curves and purify repeatedly the component b, the less volatile of them, and end up with some amount of it. and there ' ll be some balance between the amount that you feel like you need to end up with and how pure you need it to be. any questions about how this works? so purification of less volatile components. now, how much of each of these quantities in each of these phases? so, pertinent to this discussion, of course we need to know that. if you want to try to optimize a procedure like that, of course it ' s going to be crucial to be able to understand and calculate for any pressure that you decide to raise to, just how many moles do you have in each of the phases? so at the end of the day, you can figure out, ok, now when i reach a certain degree of purification, here ' s how much of the stuff i end up with. well, that turns out to be reasonably straightforward to
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phases? so at the end of the day, you can figure out, ok, now when i reach a certain degree of purification, here ' s how much of the stuff i end up with. well, that turns out to be reasonably straightforward to do. and so what i ' ll go through is a simple mathematical derivation. and it turns out that it allows you to just read right off the diagram how much of each material you ' re going to end up with. so, here ' s what happens. this is something called the lever rule. how much of each component is there in each phase? so let ' s consider a case like this. let me draw yet once again, just to get the numbering consistent. with how we ' ll treat this. so we ' re going to start here. and i want to draw it right in the middle, so i ' ve got plenty of room. and we ' re going to go up to some pressure. and somewhere out there, now i can go to my coexistence curves. liquid. and gas. and i can read off my values. so this is the liquid xb. so i ' m going to go up to some point two, here ' s xb of two. here ' s yb of two. great. now let ' s get these written in. so let ' s just define terms a little bit. na, nb. or just our total number of moles. ng and n liquid, of course, total number of moles. in the gas and liquid phases. so let ' s just do the calculation for each of these two cases. we ' ll start with one. that ' s the easier case. because then we have only the gas. so at one, all gas. it says pure gas in the notes, but of course that isn ' t the pure gas. it ' s the mixture of the two components. so. how many moles of a? well it ' s the mole fraction of a in the gas. times the total number of moles in the gas. let me put one in here. just to be clear. and since we have all gas, the number of moles in the gas is just the total number of moles. so this is just ya at one times n total. let ' s just write that in. and of course n total is equal to na plus nb. so now let ' s look at condition two. now we have to look a little more carefully
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this is just ya at one times n total. let ' s just write that in. and of course n total is equal to na plus nb. so now let ' s look at condition two. now we have to look a little more carefully. because we have a liquid gas mixture. so na is equal to ya at pressure two. times the number of moles of gas at pressure two. plus xa, at pressure two, times the number of moles of liquid at pressure two. now, of course, these things have to be equal. the total number of moles of a didn ' t change, right? so those are equal. then ya of two times ng of two. plus xa of two times n liquid of two, that ' s equal to ya of one times n total. which is of course equal to ya of one times n gas at two plus n liquid at two. i suppose i could be, add that equality. of course, it ' s an obvious one. but let me do it anyway. the total number of moles is equal to na plus nb. but it ' s also equal to n liquid plus n gas. and that ' s all i ' m taking advantage of here. and now i ' m just going to rearrange the terms. so i ' m going to write ya at one minus ya at two, times ng at two, is equal to, and i ' m going to take the other terms, the xa term. xa of two minus ya of one times n liquid at two. so i ' ve just rearranged the terms. and i ' ve done that because now, i think i omitted something here. ya of one times ng. no, i forgot a bracket, is what i did. ya of one there. and i did this because now i want to do is look at the ratio of liquid to gas at pressure two. so, ratio of i ' ll put it gas to liquid, that ' s ng of two over n liquid at two. and that ' s just equal to xa of two minus ya at one minus ya at one minus ya at two. so what does it mean? it ' s the ratio of these lever arms. that ' s what it ' s telling me. i can look, so i raise the pressure up to two. and so here ' s xb at two, here ' s yb at two. and i ' m here somewhere. and this little amount and this
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it ' s telling me. i can look, so i raise the pressure up to two. and so here ' s xb at two, here ' s yb at two. and i ' m here somewhere. and this little amount and this little amount, that ' s that difference. and it ' s just telling me that ratio of those arms is the ratio of the total number of moles of gas to liquid. and that ' s great. because now when i go back to the problem that we were just looking at, where i say, well i ' m going to purify the less volatile component by raising the pressure until i ' m at coexistence starting in the gas phase. raise the pressure, i ' ve got some liquid. but i also want some finite amount of liquid. but i don ' t want to just, when i get the very, very first drop of liquid now collected, of course it ' s enriched in the less volatile component. but there may be a minuscule amount, right? so i ' ll raise the pressure a bit more. i ' ll go up in pressure. and now, of course, when i do that the amount of enrichment of the liquid isn ' t as big as it was if i just raised it up enough to barely have any liquid. then i ' d be out here. but i ' ve got more material in the liquid phase to collect. and that ' s what this allows me to calculate. is how much do i get in the end. so it ' s very handy. you can also see, if i go all the way to the limit where the mole fraction in the liquid at the end is equal to what it was in the gas when i started, what that says is that there ' s no more gas left any more. in other words, these two things are equal. if i go all the way to the point where i ' ve got all the, this is the amount i started with, in the pure gas phase, now i keep raising it all the way. until i ' ve got the same mole fraction in the liquid. of course, we know what that really means. that means that i ' ve gone all the way from pure gas to pure liquid. and the mole fraction in that case has to be the same. and what this is just telling us mathematically is, when that happens this is zero. that means i don ' t have any gas left. yeah. professor : no. because, so it
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mole fraction in that case has to be the same. and what this is just telling us mathematically is, when that happens this is zero. that means i don ' t have any gas left. yeah. professor : no. because, so it ' s the mole fraction in the gas phase. but you ' ve started with some amount that it ' s only going to go down from there. professor : yeah. yeah. any other questions? ok. well, now what i want to do is just put up a slightly different kind of diagram, but different in an important way. namely, instead of showing the mole fractions as a function of the pressure. and i haven ' t written it in, but all of these are at constant temperature, right? i ' ve assumed the temperature is constant in all these things. now let ' s consider the other possibility, the other simple possibility, which is, let ' s hold the pressure constant and vary the temperature. of course, you know in the lab, that ' s usually what ' s easiest to do. now, unfortunately, the arithmetic gets more complicated. it ' s not monumentally complicated, but here in this case, where you have one linear relationship, which is very convenient. from raoult ' s law. and then you have one non - linear relationship there for the mole fraction of the gas. in the case of temperature, they ' re both, neither one is linear. nevertheless, we can just sketch what the diagram looks like. and of course it ' s very useful to do that, and see how to read off it. and i should say the derivation of the curves isn ' t particularly complicated. it ' s not particularly more complicated than what i think you saw last time to derive this. there ' s no complicated math involved. but the point is, the derivation doesn ' t yield a linear relationship for either the gas or the liquid part of the coexistence curve. ok, so we ' re going to look at temperature and mole fraction phase diagrams. again, a little more complicated mathematically but more practical in real use. and this is t. and here is the, sort of, form that these things take. so again, neither one is linear. up here, now, of course if you raise the temperatures, that ' s where you end up with gas. if you lower the temperature, you condense and get the liquid. so, this is ta star. tb star. so now i want to stick with a as
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course if you raise the temperatures, that ' s where you end up with gas. if you lower the temperature, you condense and get the liquid. so, this is ta star. tb star. so now i want to stick with a as the more volatile component. at constant temperature, that meant that pa star is bigger than pb star. in other words, the vapor pressure over pure liquid a is higher than the vapor pressure over pure liquid b. similarly, now i ' ve got constant pressure and really what i ' m looking at, let ' s say i ' m at the limit where i ' ve got the pure liquid. or the pure a. and now i ' m going to, let ' s say, raise the temperature until i ' m at the liquid - gas equilibrium. that ' s just the boiling point. so if a is the more volatile component, it has the lower boiling point. and that ' s what this reflects. so higher pb star a corresponds to lower ta star a. which is just the boiling point of pure a. so, this is called the bubble line. that ' s called the dew line. all that means is, let ' s say i ' m at high temperature. i ' ve got all gas. right no coexistence, no liquid yet. and i start to cool things off. just to where i just barely start to get liquid. what you see that as is, dew starts forming. a little bit of condensation. if you ' re outside, it means on the grass a little bit of dew is forming. similarly, if i start at low temperature, all liquid now i start raising the temperature until i just start to boil. i just start to see the first bubbles forming. and so that ' s why these things have those names. so now let ' s just follow along what happens when i do the same sort of thing that i illustrated there. i want to start at one point in this phase diagram. and then start changing the conditions. so let ' s start here. so i ' m going to start all in the liquid phase. that is, the temperature is low. here ' s xb. and my original temperature. now i ' m going to raise it. so if i raise it a little bit, i reach a point at which i first start to boil. start to find some gas above the liquid. and if i look right here, that ' ll be my composition. let me raise it a little farther
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if i raise it a little bit, i reach a point at which i first start to boil. start to find some gas above the liquid. and if i look right here, that ' ll be my composition. let me raise it a little farther, now that we ' ve already seen the lever rule and so forth. i ' ll raise it up to here. and that means that out here, i suppose i should do here. so, here is the liquid mole fraction at temperature two. xb at temperature two. this is yb at temperature two. the gas mole fraction. so as you should expect, what ' s going to happen here is that the gas, this is going to be lower in b. a, that means that the mole fraction of a must be higher in the gas phase. that ' s one minus yb. so xa is one minus - - ya, which is one minus yb higher in gas phase. than xa, which is one minus xb. in other words, the less volatile component is enriched up in the gas phase. now, what does that mean? that means i could follow the same sort of procedure that i indicated before when we looked at the pressure mole fraction phase diagram. namely, i could do this and now i could take the gas phase. which has less of b. it has more of a. and i can collect it. and then i can reduce the temperature. so it liquefies. so i can condense it, in other words. so now i ' m going to start with, let ' s say i lower the temperature enough so i ' ve got basically pure liquid. but its composition is the same as the gas here. because of course that ' s what that liquid is formed from. i collected the gas and separated it. so now i could start all over again. except instead of being here, i ' ll be down here. and then i can raise the temperature again. to some place where i choose. i could choose here, and go all the way to hear. a great amount of enrichment. but i know from the lever rule that if i do that, i ' m going to have precious little material over here. so i might prefer to raise the temperature a little more. still get a substantial amount of enrichment. and now i ' ve got, in the gas phase, i ' ll further enriched in component a. and again i can collect the gas. condense it. now i ' m out here somewhere
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more. still get a substantial amount of enrichment. and now i ' ve got, in the gas phase, i ' ll further enriched in component a. and again i can collect the gas. condense it. now i ' m out here somewhere, i ' ve got all liquid and i ' ll raise the temperature again. and i can again keep walking my way over. and that ' s what happens during an ordinary distillation. each step of the distillation walks along in the phase diagram at some selected point. and of course what you ' re doing is, you ' re always condensing the gas. and starting with fresh liquid that now is enriched in more volatile of the components. so of course if you ' re really purifying, say, ethanol from an ethanol water mixture, that ' s how you do it. ethanol is the more volatile component. so a still is set up. it will boil the stuff and collect the gas and and condense it. and boil it again, and so forth. and the whole thing can be set up in a very efficient way. so you have essentially continuous distillation. where you have a whole sequence of collection and condensation and reheating and so forth events. so then, in a practical way, it ' s possible to walk quite far along the distillation, the coexistence curve, and distill to really a high degree of purification. any questions about how that works? ok. i ' ll leave till next time the discussion of the chemical potentials. but what we ' ll do, just to foreshadow a little bit, what i ' ll do at the beginning of the next lecture is what ' s at the end of your notes here. which is just to say ok, now if we look at raoult ' s law, it ' s straightforward to say what is the chemical potential for each of the substances in the liquid and the gas phase. of course, it has to be equal. given that, that ' s for an ideal solution. we can gain some insight from that. and then look at real solutions, non - ideal solutions, and understand a lot of their behavior as well. just from starting from our understanding of what the chemical potential does even in a simple ideal mixture. so we ' ll look at the chemical potentials. and then we ' ll look at non - ideal solution mixtures next time. see you then.
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topics covered : encapsulation, inheritance, shadowing instructor : prof. eric grimson, prof. john guttag operator : the following content is provided under a creative commons license. your support will help mit opencourseware continue to offer high quality educational resources for free. to make a donation or view additional materials from hundreds of mit courses, visit mit opencourseware at ocw. mit. edu. professor : last lecture we were talking about classes, and object - oriented programming, and we ' re going to come back to it today. i ' m going to remind you, we were talking about it because we suggested it is a really powerful way of structuring systems, and that ' s really why we want to use it, it ' s a very common way of structuring systems. so today i ' m going to pick up on a bunch of more nuanced, or more complex if you like, ways of leveraging the power of classes. but we ' re going to see a bunch of examples that are going to give us a sense. i ' m going to talk about inheritance, we ' re going to talk about shadowing, we ' re going to talk about iterators. but before get to it, i want to start by just highlighting, sort of, what was the point of classes? so i ' ll remind you. a class, i said, was basically a template for an abstract data type. and this was really to drive home this idea of modularity. i want the ability to say, i ' ve got a set of things that naturally belong together, i ' m going to cluster them together, i want to treat it like it ' s a primitive, i want to treat it like it ' s a float or an int or a string. is this going to be a point or a segment or something different like that. so it ' s really a way, as i said, of just trying to cluster data together. and this is a notion of modularity slash abstraction where i ' m treating them as primitives. but the second thing we talked about is that we also have a set of methods, using the special name method because we ' re talking classes. but basically functions that are designed to deal with this data structure. we ' re trying to group those together as well. so we cluster data and methods. second key thing we said was, in the ideal case, which unfortunately python isn ' t, but we ' ll come back
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to deal with this data structure. we ' re trying to group those together as well. so we cluster data and methods. second key thing we said was, in the ideal case, which unfortunately python isn ' t, but we ' ll come back to that, in the ideal case, we would have data hiding, and by data hiding, which is sort of a version of encapsulation, what we meant was that you could only get to the internal pieces of that data structure through a proscribed method. proscribed meaning it ' s something i set up. so data hiding saying, you would only access the parts through a method. and as we said, unfortunately python does not enforce this. meaning that i could create one of these data structures, ideally i ' d have a method, that i ' m going to see some examples of that i used to get the parts out, unfortunately in python you could take the name the instance dot some internal variable you ' ll get it back. it is exposed. and this is actually just not a good idea. so i suggested in my very bad humor, that you practice computational hygiene and you only use appropriate methods to get the parts out. ok didn ' t laugh the joke last time, you ' re not going to laugh at it this time, i don ' t blame you. all right, and then the last piece of this is that we said the class is a template. when we call that class, it makes an instance. so class is used to make instances, meaning particular versions, of that structure, and we said inside the instances we have a set of attributes. internal variables, methods, that are going to belong to that structure. ok, so with that in mind, here ' s what i want to do. i ' m going to show you a set of examples, and i want to warn you ahead of time, the code handout today is a little longer than normal because we want to build essentially an extended example of a sequence of examples of classes. we ' re going to see the idea, of which we ' re gonna talk about, of inheritance or hierarchy, in which we can have classes that are specializations of other classes. we ' re gonna see how we can inherit methods, how we can shadow methods, how we can use methods in a variety of ways. so this is a way of suggesting you may find it more convenient to put notes on the code handout rather than in your own notes. do whatever you like, but
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we can shadow methods, how we can use methods in a variety of ways. so this is a way of suggesting you may find it more convenient to put notes on the code handout rather than in your own notes. do whatever you like, but i just wanted to alert you, we ' re going to go through a little more code than normal. so, the little environment i ' m going to build is an environment of people. i ' ll build a simple little simulation of people. so i ' m going to start off with the first class, which i ' ve got up on the screen, and it ' s on your handout as well, which is i ' m going to build an instance, or a class rather, of persons. i ' m going to draw a diagram, which i ' m gonna try and see if i can do well, over here, of the different objects we ' re going to have. so i ' ve got, a class, and by the way a class is an object. instances are also objects, but classes are objects. we ' re gonna see why we want that in a second. because i ' m gonna build an object, sorry a class, called a person. now, let ' s walk through some of the pieces here. the first one is, there ' s something a little different. remember last time we had that keyword class and then a name, that name, in this case, person says this is the name for the class, and then we would have just had the semicolon and a bunch of internal things. here i ' ve got something in parens, and i want to stress this is not a variable. all right, this is not a def, this is a class. i ' m going to come back to it, but what this is basically saying is that the person class is going to inherit from another class, which in this case is just the built - in python object class. hold on to that thought, it ' s going to make more sense when we look at a little more interesting example, but i want to highlight that. all right now, if we do this, as i said before, we can create a version of a person, let me just call it per, person. ok? and what we said last time is, when we wanted to create an instance inside of this class definition, we ' ve got one of those built - in things called init. i ' m gonna again remind you, some of
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person. ok? and what we said last time is, when we wanted to create an instance inside of this class definition, we ' ve got one of those built - in things called init. i ' m gonna again remind you, some of the methods we have, underbar underbar init is going to be the thing that creates the instance. actually slightly misspeaking, actually python creates the instance, but it ' s one thing that fills it in. so in this case, i ' m going to give it 2 arguments : frank foobar now, you might have said, wait a minute, init here has 3 arguments : self, family name, and first name. so again, just to remind you, what we said happens here is that when i call this class, person, i ' m creating an instance. we ' ll draw a little instance diagram down here. i ' m going to give it the name per. and i should have said inside of person, we ' ve got a set of things. we ' ve got our underbar underbar init, we ' ve got, what else do i have up there? family name. and a bunch of other methods, down to say. what happens inside of python is, when we called the class definition, person, it creates an instance, there it is. think of it as a pointer to a spot in memory, and then what we do is, we call, or find, that init method, up here, and we apply it. and the first argument self, points to the instance. so this object here is what self looks at. now you can see what init ' s going to do. it says, oh, inside of self, which is pointing to here, let me bind a variable, which was, can read that very carefully, it ' s family underbar name, to the value i passed in, which was 4. same thing with first name. ok, so the reason i ' m stressing this is, self we do not supply explicitly, it is supplied as pointing to the instance, it ' s giving us that piece of memory. and that is what then gets created. so here ' s, now, the instance for per. ok, and i put a little label on there, i ' m going to call that an isalink, because it is an instance of that class. god bless you. all right, so once we got this, let ' s look at what we can
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and i put a little label on there, i ' m going to call that an isalink, because it is an instance of that class. god bless you. all right, so once we got this, let ' s look at what we can do with person. that ' s why i built person here. and as i said, i ' ve already bound basically, those two pieces. if i want to get a value out, i can give person, or per, rather, this instance, a messaging. in this case i want to get family, what did i say, family name out, now, again i want to stress, what is happening here? per is an instance, it ' s this thing here. when i say per dot family name, i ' m sending it a message, in essence what that does is, it says, from here it ' s going to go up the chain to this class object and find the appropriate method, which was family name. it is then going to apply that to self, which points to this instance. and that allows it, therefore, is you can see on the code, to look up under self, what ' s the binding for family name, and print it back up. so self is always going to point to the instance i want and i can use it. ok what else do we have in here? we can get the first name, that ' s not particularly interesting. we ' ve got 2 other special methods : that ' s cmp and str. all right, cmp is our comparison method. and since i, i was about to say i blew it last time, i misspoke last time, a wonderful phrase that politicians like to use, i misspoke last time. let me clarify again what cmp will do. underbar underbar cmp is going to be the method you ' re going to use to compare two instances of an object. now, let ' s back up for second. if i wanted to test equality, in fact i could use underbar underbar eq, under under. it ' s natural to think about an equality tester as returning a boolean, it ' s either gonna be true or false, because something ' s either equal to or not. in many languages, comparisons also return booleans, which is why i went down this slippery slope. for many languages, either it ' s greater than or it ' s not. but python is different. python use cmp, in fact
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2025-12-19T07:35:33.353277
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. in many languages, comparisons also return booleans, which is why i went down this slippery slope. for many languages, either it ' s greater than or it ' s not. but python is different. python use cmp, in fact it has a built in cmp, which is what we ' re relying on here. where am i, right there. and what cmp returns is 1 of 3 values. given 2 objects, it says if the first one is less than the second one, it returns - 1, if it ' s equal it returns 0, if it ' s greater than, it returns 1. so it allows you this broader range of comparisons. and if you think about it, cmp, you could apply on integers, you could apply it on floats, apply it on strings. so it ' s overloaded, it has the ability to do all of those. and in this case what we ' re saying is, given 2 objects, let ' s create a tuple of the first, sorry, family and first name of ourselves, and other is another object, family and first name of that, and then just use cmp to compare them. all right, so it ' s going to use the base pieces. ok, so it gives me a way of doing comparisons. and str we saw last time as well, this is cmp does comparison, and str is our printed representation. ok. so what we ' ve got now, is a simple little class. we ' ve also got two methods there. i want to look at them, we ' re gonna come back to them, but they start to highlight things we can do with our classes. so i ' ve built one simple version of it here, which is per. and notice i ' ve got another method, right up here, called say. and say takes two arguments, for the moment the second argument, or the first argument ' s, not going to make a lot of sense, but say takes two arguments besides itself. it ' s going to take another object to which it ' s saying something and the thing to say. since i only have one object here, i ' m going to have person talk to himself. you may have met a few other undergraduates who have this behavior. i ' ll have him talk to himself and say, just some random message the faculty members occasionally worry about. ok, what does this thing do? now you ' re going to see some of the power of this
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subdomain_quantum_cryptography
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HuggingFaceFW/fineweb-edu
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2025-12-19T07:35:33.354129
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undergraduates who have this behavior. i ' ll have him talk to himself and say, just some random message the faculty members occasionally worry about. ok, what does this thing do? now you ' re going to see some of the power of this. again, remember, i ' m down here, i ' m sending this the message say, it ' s going to go up the chain to find the say message in person. and what does say do, it says given another object and some string, it ' s going to return, oh, and interesting things, part of which you can ' t see on the screen. first what it does, is it gets first name of self. remember self is pointing to this instance, so it ' s simply looks up that binding, which is frank. it ' s going to create a string in which it adds to that the family name of self, and then another thing that says to, and then ah, i ' m now going to send a message to the other object, saying give me your first name. going to add that to the second piece, and you can see in this case it happens to be the same first and family name. and then at the end of it, which you can ' t see here but you can see in your handout, i just append the whole string, so it spits it out. what ' s the point of this, other than i can get it to say things? notice, i can now reference values of the instance. but i can also get values of other instances, by sending in a message. and that ' s why we have that form right there. and then it glued all together. if you think about this for a second, you might say, wait a minute, actually you might have said wait a minute a while ago, why am i just using the variable name there in the function over here? well in fact, i could ' ve used the function here, first name open close, right? it would have done the same thing. but because i know i ' m inside the instance, it ' s perfectly reasonable to just look up the value. ok, i could have, although i don ' t want you to do it, have done the same thing there and used underbar, sorry, first name underbar, sorry, first underbar name, but that ' s really breaking this contract that i want to happen. i should send the message to get the method back out. so again the standard
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subdomain_quantum_optics
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2025-12-19T07:35:33.355012
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there and used underbar, sorry, first name underbar, sorry, first underbar name, but that ' s really breaking this contract that i want to happen. i should send the message to get the method back out. so again the standard practices is if you know you ' re inside the object, you can just access the values. if you ' re doing it with any other objects, send it a message to get it out. ok, now, that gives you an ability to say, let ' s look at one more example here, and then we ' re going to start building our hierarchy, which is, that this person can also sing. and we ' ve got a little sing method here. and notice what it does, it ' s going to sing to somebody, i guess you ' re part of the chorallaries. you ' re going to sing something, and notice what it does, it ' s simply going to use its say method, but add at the end of whatever ' s being said, just tra la la at the end. so this is now an example of a method using another method. why would you want that? it ' s nice modularly. i have one method that ' s doing saying, i have another method that ' s just building on it. so if i have is person sing to themselves, not a highly recommended activity, it would help if i had it sing to itself, not sing to sing, sorry about that. notice what it does. looks like exactly like a say method, except it ' s got tra la la at the end. don ' t worry i ' m not going to sing to you. i ' ll simply say the words. power of this, other than the silly examples. you see how i can access variables of the instance, how i can access variables of other instances, going to come back to that, and how i can use versions of my own methods to implement other methods. in this case sing is using say as part of what it wants to get out. ok, so we got a simple little example. now, let ' s start adding some other pieces to this. ok, and what do i want to add. find my spot here. ok, we ' re going to add an mit person. sorry, machine is - - do this, let ' s go down. ok so i ' m going to add an mit person. look at the code for second. aha! notice what this says. mit person
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subdomain_quantum_cryptography
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HuggingFaceFW/fineweb-edu
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2025-12-19T07:35:33.355898
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to add an mit person. sorry, machine is - - do this, let ' s go down. ok so i ' m going to add an mit person. look at the code for second. aha! notice what this says. mit person says it inherits from person. that is, that ' s the first thing in parens up there. it says, you know, class of mit person is person. what that is saying is, that this is a specialization of the person class. or another way of saying it is, we have a super class, in this case it ' s person. and we have a subclass, in this case its mit person. and we ' re going to walk through some examples, but what it says is that that subclass of mit person can inherit the attributes of the person class. can inherit the methods, it can inherit variables. ok, what does mit person do? well, here ' s 1 of the new things it does. it has a local variable called next id num, which is initially set to 0. see that up there. and then it ' s got some methods, it ' s got an init method, a get id method, a few other things. ok, let ' s run this. in particular, i go back down to this one. let me just uncomment this and do it here. assuming my machine will do what i want it to do, which it really doesn ' t seem to want to do today. try one more time. thank you, yep. still not doing it for me, john. ok, we type it. no idea what python doesn ' t like me today, but it doesn ' t. so we ' re gonna define p 1, i ' ve lost my keyboard, indeed i have. try one more time. p 1 mit person, see how fast i can type here - - ok, now, let ' s look at what the code does, because again it ' s going to highlight some things. i called mit person, push this up slightly, it ' s going to create an instance down here, i called p 1. and when i would do that, i ' m gonna initialize it. so i ' ve got, right up here, an initializer, init for mit person, takes in the family name and the first name. notice what it does. huh. it says, if i ' m sitting here at mit person, i ' m going to go up and
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subdomain_quantum_field_theory
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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2025-12-19T07:35:33.356694
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here, an initializer, init for mit person, takes in the family name and the first name. notice what it does. huh. it says, if i ' m sitting here at mit person, i ' m going to go up and inherit from person its init function and call it. and what am i calling it on? i ' m calling it on self, which is pointing to this object, so i ' ve still got it, and then i ' m then going to apply the base initialization. and that does exactly what you ' d expect, which is just going to create a binding for family name down here. as well as some other things. so this is an example of inheritance. mit person inherits the init method from person, can get access to by simply referring to it, and i refer to it right there. and it ' s take the person class, get its init and apply it to my instance plus those things. so i ' m just using the same piece of code notice the second thing it does. it says inside of self, i ' m going to bind the local variable id name to the value of next id name in mit person. self is down here, id num, sorry, not id name. i ' m going to bind that to the value that i find my going up to here, which is 0, and having done that, i simply increment that value. ok? so what has this done? it says i now have captured in the class, a local variable that i can keep track of. and when i use it, every time i generate an example, let me build another one. i make p 2 another mit person. ok, i can do things like saying, what is the id number for each of these. first one is 0, second one is 1, which makes sense, right? i ' m just incrementing a global variable. now, things i want you to see about this. now that i ' ve got a beginning of a hierarchy, i have this notion of inheritance. i can ask a function inside one class to use a function from a class that it can reach by going up the chain. i just did it there. i can ask it to go get values of variables, right, so that looks good. what else do we have in person or mit person? well, we can get the id number, we just did. we have a thing to do with this string. notice it ' s
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subdomain_quantum_field_theory
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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2025-12-19T07:35:33.357605
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get values of variables, right, so that looks good. what else do we have in person or mit person? well, we can get the id number, we just did. we have a thing to do with this string. notice it ' s going to print out something a little different. in fact, there ' s a kind of funky form there. which just says, if i want to print it out, i ' m gonna create, what this says to do is, i ' m gonna create an output template that has that structure to it, but where i see that percent s i ' m going to substitute this value for the first one, that value for the second. so if i say, what is p 1? it says ok, mit person fred smith. on the other hand, if i said, what is per, which is that thing i build earlier, it had a different string method, which is just print out person, those pieces. all right, one last piece to this and we ' re going to add to it. suppose i want fred to say something. say something to jane. ok, he said it. where ' s the say method? ok, fred is an instance of an mit person. where ' s the say method? well, there isn ' t one there, but again, that ' s where the hierarchy comes in. fred is this object here, i ' m sending it the message say. that turns into going up the chain to this object, which is the class object, and saying find a say method and apply it to that instance. fudge - knuckle, it ain ' t here. don ' t worry about it, because it says if i can ' t find one there, i ' m going to go up the chain to this method, sorry to this class, and look for a method there. which there was one, i have a say method. it ' s going to use that say method. apply to it. well, you might say, ok, what happens if it isn ' t there? well, that ' s where, remember i defined person to be an instance of an object, it will go up the chain one last time to the base object in python to see is there a method there or not. probably isn ' t a say method for an object, so at that point it ' s going to raise an exception or throw an error. but now you again see this idea that the inheritance lets you capture methods. now you might
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subdomain_quantum_gravity
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2025-12-19T07:35:33.358538
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there or not. probably isn ' t a say method for an object, so at that point it ' s going to raise an exception or throw an error. but now you again see this idea that the inheritance lets you capture methods. now you might say, why not just put a say method inside of mit person? well, if you wanted it to do something different, that would be the right thing to do. but the whole notion here ' s that i ' m capturing modularity, i ' ve got base methods up in my base class. if i just want to use them i ' m just going to inherit them by following that chain, if you like, basically up the track. ok, so we ' ve got an mit person, we can use that. let ' s add a little bit more to our hierarchy here. i ' m going to create, if i can do this right, a specialization of an mit person, which is an undergraduate. a special kind of mit person. all right, so if i go back up here, even though my thing is not going to let me do it, let ' s build an undergraduate. ok, there ' s the class definition for an undergrad. we ' re just starting to see some of the pieces, right, so in an undergraduate, where am i here, an undergraduate. ok, it ' s also got an initialization function. so if i call undergrad, i ' m gonna make an undergrad here, again let me go back down here, line ug 2 it ' s making undergrad, jane doe. now, what happens when i do the initialization here? notice what goes on. it simply calls the person initialization method. all right, so i ' m down here. i ' m going to call the person initialization method, what did do? sorry, the mit person method, it calls the person method. just walking up the chain, that ' s going to do exactly what i did with all the other ones, so i now have a family name and a first name. so i can, for example, say family name and get it back out. all right? and then, other things that i can do, well i can set what year the person ' s in, i can figure out what year they ' re in, there ' s this unfortunate overflow error if you ' ve hung around too long, but that ' s not going to happen to you. and i ' ve now got a say method
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subdomain_quantum_field_theory
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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2025-12-19T07:35:33.359400
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in, i can figure out what year they ' re in, there ' s this unfortunate overflow error if you ' ve hung around too long, but that ' s not going to happen to you. and i ' ve now got a say method here, so let ' s look what happens if i ask the undergraduate to say something. ok, it ' s not a realistic dialogue i know, but, what did this method do? i asked this object to do a say. and notice what it does. it simply passes it back up to mit person. there ' s that inheritance again. it ' s saying, i ' m going to have my base say method say something. i ' m going to say it to a person, but all i ' m going to do because undergraduates in my experience, at least, are always very polite, i ' m going to put " excuse me but " at the front of it. ok, what am i trying to show you here? i know the jokes are awful, but what am i trying to show you here? that i can simply pass up the chain to get it. in fact, what method does the final say here? what class does it come from? person class, yes, thank you. it goes all the way up to person, right, because mit person didn ' t have a say. so i can simply walk up the chain until i find the method i want to have. now this is an example of shadowing. not a great example, but it ' s a beginning example of shadowing, in that this same method for an undergraduate, shadows the base say method, it happens to call it, but it changes it. it puts " excuse me but " at the front, before it goes on to do something. now again, i could have decided here to actually copy what the original say method did, stitch all the other things together. but again, that loses my modularity. i ' d really to only have to change it in one place. so by putting my say method up in person, i can add these nuances to it, and it lets me have something that has that variation. if i decide i want to change what say does, i only have to change it in one place. it is in the person class definition, and everything else will follow through for free. ok, so now i ' ve got an undergrad, right? let ' s look at a couple of variations of what happens here. so first of all
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subdomain_quantum_computing
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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2025-12-19T07:35:33.360948
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. it is in the person class definition, and everything else will follow through for free. ok, so now i ' ve got an undergrad, right? let ' s look at a couple of variations of what happens here. so first of all, i can - - yes? professor 2 : shadowing here is often sometimes called overriding. professor : yes, thank you, because i ' m going to do a pure example of shadowing in a second, john right. also called overriding. part of the reason i like the phrase shadow is, if you think about it as looking at it from this direction, you see this version of init before you see the other ones, or you see that version of say, but it is overriding the base say example. ok, so i can say, what does p 1, sorry, yes, what does undergrad look like? and i said wait a minute, mit person, not undergrad, is that right? well, where ' s the str method? i didn ' t define one in undergrad, so it again tracks up the chain and finds the str method here, so it ' s ok undergrads are mit people most the time, so it ' s perfectly fine. ok, now, i have built into this also these cmp methods. so i ' ve got two examples. i ' ve got undergrad, or ug. and then i ' ve got poor old frank foobar back there, per person. so suppose i want to compare them? what do you think happens here? compare sounds weird, right, i compare an undergraduate to a person. i don ' t know what that ' s doing, some kind of weird psychological thing, but what do you think happens in terms of the code here if i run this. i know it ' s a little hard because you got a lot of code to look at. do i have a cmp method defined somewhere? yeah. so, it ' s hard to know what it ' s going to do, but let ' s look at it. hmm. now sometimes i type things and i got errors i don ' t expect, this one i did expect. so what happened here? well let ' s talk about what happens if i do that comparison i was doing, what was i doing? ug greater than per? what unwinds into is, i ' m going to send to ug, that instance, a cmp method. this is really going to
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subdomain_quantum_field_theory
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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2025-12-19T07:35:33.361868
|
if i do that comparison i was doing, what was i doing? ug greater than per? what unwinds into is, i ' m going to send to ug, that instance, a cmp method. this is really going to become something like ug dot under under cmp under under applied to per. i think that ' s close. what does that do? it says starting in ug, i ' m going to look for the first cmp method i could find, which is actually sitting here. i had a cmp method in mit person. if you look at your code, what does it do? it looks up the id numbers to compare them. well the, ug has an id number because it was created along this chamber. remember per over here was just created as a person. it doesn ' t have an id number, so that ' s why it complaints. ok, happens if i do that? compare per to ug. how many people think i get an error? wow. how many people think i ' m going to get either true or false out of this? a few brave hands. why? can i ask you, please? why do you think i ' m going to get a, doesn ' t matter whether it ' s true or false, why am i going to have something work this time that didn ' t work last time? professor : yeah, exactly. and in case you didn ' t hear it, thank you, great answer, sorry, terrible throw. in this case i ' m using per, that ' s the first part, so it ' s not symmetric. it ' s gonna use per to do the look up. and as it was said there, per over here goes up and finds a cmp method here which it can apply. in that case, it simply looked at, remember, it took the tuples of first and last name which are both defined here, and did some comparison on that. so this is a way of again pointing out to you that the things are not always symmetric, and i have to be careful about where do i find the methods as i want to use them. ok? all right. let ' s add, i ' m gonna do two more classes here. let ' s add one more class, some people debate whether these are really people or not, but we ' re going to add a class called a professor. ok. now what am i doing? i ' m creating another version of class down here
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subdomain_quantum_cryptography
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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2025-12-19T07:35:33.362754
|
let ' s add one more class, some people debate whether these are really people or not, but we ' re going to add a class called a professor. ok. now what am i doing? i ' m creating another version of class down here. which again is an instance, or a subclass, sorry, not an instance, a subclass of an mit person. i see that because i built it to be there. again i ' ve got an initialization that ' s going to call the person initialization, which we know is going to go up - - i keep saying that - - going to call the mit person initialization, which is going to go up and call this one. so again i ' m going to be able to find names. and i do a couple of other different things here. i ' m gonna pass in a rank, full professor, associate professor, assistant professor, which i ' m just going to bind locally. but i ' m gonna add one other piece here, which is i ' m gonna add a little dictionary on teaching. so when i create a professor, i ' m gonna associate with it a dictionary that says, what have you been teaching? and then notice the methods i create. i ' ve got a method here called add teaching, takes, obviously a pointer to the instance. a term, which will just be a string, and a subject. and let ' s look at what it does right here. ok. in fact the call i ' m going to make, i ' m not certain i ' m going to be able to get away with it, my machine is still wonderfully broken, all right, it is, let me just show you what the calls would look like. as you can see here i ' m not going to be able to do them. but i ' m going to add teaching, as a method call with this with a string for term, and a subject number. what is this going to do? yeah, i know i ' m just worried if i restart python, i may not be able to pull the thing back in, so i ' m going to try and wing it, john, and see if i can make it happen. right, what does that teaching do? it ' s got one of those try except methods. so what does it say it ' s going to do? it ' s going to go into the dictionary associated with teaching, under the value of term, and get out a list. and it ' s
|
subdomain_quantum_gravity
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HuggingFaceFW/fineweb-edu
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<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
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|
2025-12-19T07:35:33.363642
|
s got one of those try except methods. so what does it say it ' s going to do? it ' s going to go into the dictionary associated with teaching, under the value of term, and get out a list. and it ' s going to append to the end of the list the new subject. so it ' s going to be stored in there, is then going to be term, and a list of what i taught, in case i teach more than one thing each term. it ' s going to do that, but notice it ' s a try. if in fact there is no term currently in the dictionary, started out empty, it ' s going to throw an error, sorry, not throw an error, it ' s going to raise an exception. which is a key error, in which case notice what i ' m going to do, i ' m not going to treat it as an error. i ' m simply going to say, in that case, just start off with an empty, with an initial list with just that subject in and put it in the dictionary. as i add more things in, i ' ll just keep adding things to this dictionary under that term. and if i want to find out what i ' m doing, well i can use get teaching, which says given the term, find the thing in the dictionary under that term and return it. if i get an error, i ' m going to raise it, which says there is nothing for that term, and in that case i guess i ' m just going to return none. ok? and then the other two pieces we ' re going to have here, and we want to look at a little more carefully, i just wanted to show you that example, is a professor can lecture, and a professor can say something. look at the say method, because this now add one more nuance to what we want to do here. and i think in interest of making this go, let me actually, since i ' m not going to get my machine to do this right, let me create a couple of professors. if i look at what that is, it ' s an mit person because i didn ' t have any separate string thing there, and we will create a more important professor. what rank do you want, john? do you want to stay full? professor 2 : undergraduate. professor : undergraduate, right, a lot more fun i agree. sorry about that, and we can again just see what that looks like.
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subdomain_quantum_computing
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HuggingFaceFW/fineweb-edu
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2025-12-19T07:35:33.364541
|
professor. what rank do you want, john? do you want to stay full? professor 2 : undergraduate. professor : undergraduate, right, a lot more fun i agree. sorry about that, and we can again just see what that looks like. and that of course, we ' ll print out, he ' s also an mit person. but now here ' s what i want to do. i want to say something to my good colleague professor guttag. actually i ' m going to start a separate - - i ' m going to say something to a smart undergraduate. so if i say, remember we have ug defined as an undergraduate, let me do something a little different here. well let, me do it that way. it says, i don ' t understand why you say you were enjoying 6. 00. not a good thing to say, right, but if i say to my good colleague professor guttag. i have to spell say right, i know, i need help with this, what can i say? we flatter each other all the time. it ' s part of what makes us feel good about ourselves. why is the sky blue? i enjoyed your paper, but why is the sky blue? ok, terrible examples, but what ' s going on here? one more piece that i want to add. here ' s my say method for professor, and now i ' m actually taking advantage of to whom i am saying something. notice again, what does it do? there ' s the self argument, that ' s just pointing to the instance of me. i ' m passing in another argument, going to call it to who, in one case it was ug, in one case it was guttag. and then the thing i want to say, ah, look what it does, it says, check the type. and the type is going to take that instance, i had an instance, for example, of a professor down here, and it ' s going to pick up what type of object it is. so if the type of the person i ' m speaking to is undergrad, let ' s pause for second. remember i started away back saying we ' re building abstract data types. well, here ' s a great example of how i ' m using exactly that, right? i ' ve got int, i ' ve got float, i now have ug, it ' s a type. so it ' s says if the object to whom i ' m speaking is an under
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subdomain_quantum_gravity
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HuggingFaceFW/fineweb-edu
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2025-12-19T07:35:33.365495
|
i ' m using exactly that, right? i ' ve got int, i ' ve got float, i now have ug, it ' s a type. so it ' s says if the object to whom i ' m speaking is an undergrad, then use the same method from person where i ' m going to put this on the front. on the other hand, if the object to whom i ' m speaking is a professor, then i ' m going to tag this on the front and use the underlying say method. on the other hand, if i ' m speaking to somebody else, i ' m just going to go lecture. all right, and when a professor lectures, they just put it ' s obvious on the end of things, as you may have noticed. what ' s the point i want you to see here? i ' m now using the instances to help me to find what the code should do. i ' m looking at the type. if the type is this, do that. if the type is this, do something different, ok? and i can now sort of build those pieces up. ok, i said one more class. notice what we ' re doing. i know they ' re silly examples, but, sorry, they are cleverly designed examples to highlight key points. what i ' m trying to do is show you how we have methods inherit methods, how have message shadow methods, how we have methods override methods, how we can use instances as types to define what the method should do. let me show you one last class, because i ' m gonna have one more piece that we want to use. and the last class is, sort of, once you ' ve got a set of professors, you can have an aggregate of them. and i don ' t know, if a group of geese are gaggle, i don ' t know what a set of professors are, john. flamers? i, you know, we ' ve got to figure out what the right collective noun here is. we ' re going to call them a faculty for lack of a better term, right? now the reason i want to show you this example is, this class, notice, it only is going to inherit from object. it actually makes sense. this is going to be a collection of things, but it ' s not a subclass of a particular kind of person. and what i want the faculty to do, is to be able to gather together a set of faculty. so if
|
subdomain_quantum_gravity
| 0.548904
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
| 18
| 0.5
|
2025-12-19T07:35:33.366340
|
sense. this is going to be a collection of things, but it ' s not a subclass of a particular kind of person. and what i want the faculty to do, is to be able to gather together a set of faculty. so if i go down here, grab this for second, and pull it down so you can see it. it looks like i ' m not going to be able to run this because my machine is broken, but basically i ' m gonna define a set of professors, and then i ' m gonna create a new class called faculty. there ' s the definition of it. it ' s got an init. you can kind of see what it does. it ' s going to set up an internal variable called names, which is initially an empty list, internal variable called ids, which is empty, an internal variable called members, which is empty, and another special variable called place, which we ' re going to come back to in a second, initially bound to none. ok, i ' ve got a method called add which i ' m going to use down here to add professors to the course 6 faculty. here ' s what i want to add to do. first of all, notice i ' m going to check the type. if this is not a professor, i ' m gonna raise an error, a type error, it ' s the wrong type of object to pass in. the second thing i ' m gonna do is say, if that ' s okay, then let me go off and get the id number. now remember, that ' s right up here, so i ' m asking the instance of the professor to go up and get the id number. and i want to make sure i only have one instance of each professor in my faculty, so if the id number is in the list of ids already, i ' m going to raise an error, sorry, raise an exception as well, saying i ' ve got a duplicate id. ok? and the reason that ' s going to come up is, notice what i do now. inside of the instant self, i take the variable names and i add to it the family name of the person i just added. ok, notice the form. i ' m using the method, there ' s the parens to get the family name of the person. i ' m just adding it to the list. i ' ve got the id number, i ' ve added the ids, and i add the object itself into members
|
subdomain_quantum_field_theory
| 0.547054
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
| 19
| 0.5
|
2025-12-19T07:35:33.367229
|
, there ' s the parens to get the family name of the person. i ' m just adding it to the list. i ' ve got the id number, i ' ve added the ids, and i add the object itself into members. so as i do this, what am i doing? i ' m creating a list, actually several lists : a list of ids, a list of the actual instances, and a list of the family names. and as a cost i want to add, that ' s why i can check and see, is this in here already or not? now, the last reason i want to do this is, i want to be able to support things like that. this is now different, right, this instance is a collection. i want to be able to do things like, for all the things in that collection, do something, like print out the family names. and to do that, i need two special forms : iter and next. ok, now let me see if i can say this cleanly. whenever i use a for, in structure, even if it was on just a normal list you built, what python is doing is returning an, what is called an iterator. which is something that we talked earlier. it ' s keeping track of where are you in the list, and how do i get to the next thing in the list? i ' m going to do the same thing here, and i ' m going to create it for this particular structure. so this little thing iter, when i call a for something in, one of these instances, it calls iter, and notice what it does. it initializes place to 0. that was that variable i had up there. that ' s basically saying i ' m at the beginning of the list. it ' s a pointer to the beginning of the list, and it returns self. just gives me back a pointer to the instance. that now allows me at each step in that loop to call next. and what does next do? next says, check to see if that value is too long, if it ' s longer than, for example, the list of names, raise an exception called stop iteration, which the for loop will use to say ok, i ' m done. i ' m going to break out of the for loop. otherwise, what am i going to do? i ' ll increment place by 1, that ' s going to move me to the next place in
|
subdomain_quantum_gravity
| 0.50184
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
| 20
| 0.5
|
2025-12-19T07:35:33.368085
|
ok, i ' m done. i ' m going to break out of the for loop. otherwise, what am i going to do? i ' ll increment place by 1, that ' s going to move me to the next place in the list, and then in this case i ' ll just return the instance itself, right? members is a list of instances, place i ' ve incremented by 1, i take 1 off of it, i get to it. so iter and next work together. iter creates this method, that ' s going to give you a pointer to the place in the structure, and then next literally walks along the structure giving you the next element and returning elements in turn so you can do something with it. right, so now what that says is, i can have classes that just have local variables. i can have classes that get methods from other variables, and i can also have classes that are collections. and i ' ve supported that by adding in this last piece. ok once you have all of that, in principle we could start doing some fun things. so let ' s see what happens if we try and make all of this go. and let me, since i ' m not going to be able to run it, let me simply do it this way. if i have my undergraduate, ug. i can - - sorry, let ' s not do it that way - - i can have undergraduate say things like - - all right, what did i just do wrong here? do i not have undergrad defined? i do. oh, i didn ' t have grimson, sorry, it ' s me, isn ' t it? thank you. the undergraduate very politely asks why he didn ' t understand, you can have the professor respond. again, it simply puts a different thing into there. on the other hand, if professor guttag asks me something about understanding, i say i really like this paper on, you do not understand, it ' s a deep paper on programming languages 5, i think, john, isn ' t it? what else can you do with this thing, right? you can have an undergraduate talk to an undergraduate, in which case they ' re still polite. or you could have - - sorry, let me do that the other way - - you could also have an undergraduate simply talk to a normal person. all right, but the good news is you know eventually you get it done, and when you ' re really done you
|
subdomain_quantum_field_theory
| 0.569347
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
| 21
| 0.5
|
2025-12-19T07:35:33.368995
|
- - sorry, let me do that the other way - - you could also have an undergraduate simply talk to a normal person. all right, but the good news is you know eventually you get it done, and when you ' re really done you can have the undergraduate be really happy about this, and so she sings to herself. ok it ' s a little silly, but notice what we ' ve just illustrated. and this is where i want to pull it together. with a simple set of classes, and the following abilities, an ability to inherit methods from subclasses, sorry from superclasses, that is having this hierarchy of things. i can create a fairly complex kind of interaction. i can take advantage of the types of the objects to help me decide what to do. and if you think about that, i know it sounds very straightforward, but you would do exactly that if you were writing earlier code to deal with some numerical problem. all right, if the thing is an integer, do this, if it ' s a float, do that, if it ' s a string, do something else. i ' m now giving you exactly the same ability, but the types now can be things that you could create. and what i ' ve also got is now the ability to inherit those methods as they go up the chain. so another way of saying it is, things that you want to come away from here, are, in terms of these classes. we now have this idea of encapsulation. i ' m gathering together data that naturally belongs as a unit, and i ' m gathering together with it methods that apply to that unit. just like we would have done with float or int. ideally, we data hide, we don ' t happen to do it here, which is too bad. basically we ' ve got the idea of encapsulation. the second thing we ' ve got is this idea of inheritance. inheritance both meaning i can inherit attributes or field values. i can inherit methods by moving up the chain. i can also the shadow or override methods, so that i can specialise. and i do all of that with this nice hierarchy of classes. so what hopefully you ' ve seen, between these two lectures, and we ' re going to come back to it in some subsequent lectures, is that this is now a different way of just structuring a computational system. now, you ' ll also get arguments, polite arguments from faculty members or other experts about which is a better
|
subdomain_quantum_cryptography
| 0.578506
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:356021a3-01be-42dc-ae50-e22e74e8edfd>
| 22
| 0.5
|
2025-12-19T07:35:33.369934
|
talk : 20. 109 ( f12 ) pre - proposal : engineering viral magnetic nanoparticles for magnetic hyperthermic cancer therapy - this is a brainstorming page. you are very welcome to write any crazy / non - crazy / inventive / conventional / knowledgeable ideas or information you may have about our project. some key words : magnetic nanoparticles ( mnp ), viruses, magnetic hyperthermia, bioengineering what is magnetic hyperthermia? how it works? under an alternating magnetic field, mnp releases heat due to relaxation of magnetic moments ( hysteresis ). this can cause an increase in temperature to the range of 41c to 47c. since tumor cells are more heat sensitive than normal cells, they will be killed by this thermal dissipation. here is an interesting tidbit from a paper i was reading : " in addition to the expected tumor cell death, hyperthermia treatment has also induced unexpected biological responses, such as tumor - specific immune responses as a result of heat - shock protein expression. these results suggest that hyperthermia is able to kill not only local tumors exposed to heat treatment, but also tumors at distant sites, including metastatic cancer cells. " ( kobayashi ) - clinical trials in prostate cancer - shows promising results when coupled with irradiation on breast cancer ( mouse ) current limitations ( this information will help us shape and define the problem. ) ( 1 ) to achieve the necessary rise in temperature with minimal dose of mnp. - in other words, this means : - high specific loss power / specific absorption rate ( slp ) of the mnp. - why is higher applied dosage bad? > leads to unnecessary heat dissipation ( 2 ) lack of knowledge about the metabolism, clearance, and toxicity of mnp. biomedical potentials of mnp - could be used as early detection for the following using mri : - drug delivery - cellular labeling and tissue targeting - purifying and separating cells and dnas - transfection by magnetic nanoparticles - tissue repair - magnetic resonance imaging ( mri ) types of relevant viruses 1. tobacco mosaic virus ( tmv ) - 18nmx300nm, helical - can withstand high temperatures up to 50c for 30mins ( conventional hyperthermia involves heating up to 50c from an external source - safe for human consumption - mann group has active research on it - 2130 molecules of coat protein 2. m13 bacteriophage -
|
subdomain_quantum_thermodynamics
| 0.579185
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:02670295-3a47-4d18-b098-38a53e1f91ab>
| 0
| 0.5
|
2025-12-19T07:35:33.383875
|
50c for 30mins ( conventional hyperthermia involves heating up to 50c from an external source - safe for human consumption - mann group has active research on it - 2130 molecules of coat protein 2. m13 bacteriophage - 6. 6nmx880nm, helical ( length is too long - pose an issue in targeting cells ) - lots of research done by the belcher group, including attaching mnps to m13 for imaging purposes - we are familiar with the system 3. cowpea chlorotic mottle virus ( ccmv ) - 26nm, icosahedral 4. cowpea mosaic virus ( cpmv ) - 27nm, icosahedral 5. brome mosaic virus ( bmv ) - 28nm, icosahedral 6. turnip yellow mosaic virus ( tymv ) - 30nm, icosahedral current work in viral mnp attachment attachment of mnps to m13 phage for in vivo imaging of prostate cancer what we propose to do see flowchart sketch. - identifying / screening for appropriate virus vehicles and tumor - specific anchoring sequencse - developing / engineering viral mnps - in vivo testing for efficacy of engineered vmnps in mouse tumor cells. we will start with using ferritin ( fe3o4 ) as the mnp. stage 1 : virus hunt - we need to investigate how the selected virus ( likely one of the following : tmv, m13, ccmv, cpmv, bmv or tpmv ) interacts with mammalian cells in vivo. stage 2 : screening for mnp binding site on virus - we will start by using fe3o4 as our mnp of interest. with this, a protein coat screen of the selected virus for a protein coat that can bind with our mnp is necessary. stage 3 : screening for tumor - specific sequence binding site on virus - we need to do a protein coat or rna screen of the virus for a region that can bind with a tumor - specific peptide sequence. if necessary, we might need to screen tumors for unique short sequences on their cell surfaces. stage 4 : virus engineering - we can now engineer wild - type viruses using specific protein coats or rna regions isolated in stage 2 and 3 to produce the viral mnp of interest. stage 5 : in vivo testing - perform an in vivo experiment by injecting the engineered viral mnps into the circulatory system of
|
subdomain_quantum_metrology
| 0.533574
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:02670295-3a47-4d18-b098-38a53e1f91ab>
| 1
| 0.5
|
2025-12-19T07:35:33.384683
|
specific protein coats or rna regions isolated in stage 2 and 3 to produce the viral mnp of interest. stage 5 : in vivo testing - perform an in vivo experiment by injecting the engineered viral mnps into the circulatory system of mice that have developed tumors. by subjecting these mice to an alternating magnetic field under standard hyperthermia conditions and measuring the change in tumor size, we will be able to quantify the efficacy of using viral mnps in magnetic hyperthermia. - experimenting with double layer mnp to increase response - target other cancerous cells - experiment with other types of viruses quantitative goals ( we can quantify with ic50 value ) - currently, with the aid of 10gy radiation, the hyperthermia treatment successfully accumulated less than 0. 3mg fe / g tissue. dosage : 0. 2mg fe per gram of mouse. say mouse is 25g, so 5mg total dosage injected. so 1 % efficiency with the aid of radiation. ( mnp sizes used : 70nm and 120nm ; murine flank breast tumors were 150mm3 ) from http : / / manalis - lab. mit. edu / publications / grover % 20pnas % 202011. pdf, we estimated that a typical cell has an average density of 1. 1g / ml. since the murine flank breast tumors were 150mm3, and 0. 25mg fe / g of tumor was detected in the tumors, we can calculate that only a total of 0. 0495mg of fe is accumulated in the tumors. this gives a % efficacy of 1 %. - south korean experiment : 75ug of mnps were injected. - from belcher lab ' s paper, what is the % efficacy of using m13? - " the actual rotations of the nanoparticles are disordered because the microviscosity of the local environment in cancer cells is not constant, and effective elasticity depends on the binding conditions between nanoparticles and membranes. " - but this is actually present because when treatment is done with individual mnps, one side of the mnp is always bound to the targeted cell, so direction is never constant! - gupta ak, naregalkar rr, vaidya vd, and gupta m. recent advances on surface engineering of magnetic iron oxide nanoparticles and their biomedical applications. future medicine. 2007. 2 ( 1 ), 23 - 39. - bakoglidis kd, simeonidis k
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subdomain_quantum_optics
| 0.552648
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:02670295-3a47-4d18-b098-38a53e1f91ab>
| 2
| 0.5
|
2025-12-19T07:35:33.385513
|
##d, and gupta m. recent advances on surface engineering of magnetic iron oxide nanoparticles and their biomedical applications. future medicine. 2007. 2 ( 1 ), 23 - 39. - bakoglidis kd, simeonidis k, sakellari d, g. stefanou, and angelakeris m. size - dependent mechanisms in ac magnetic hyperthermia response of iron - oxide nanoparticles. ieee transactions on magnetics. 2012. 48 : 1320 - 1323. - great layman ' s way of explaining magnetic hyperthermia http : / / trialx. com / curetalk / 2012 / 11 / cancer - treatment - multifunctional - magnetic - nanoparticles - for - molecular - imaging - and - hyperthermia / - a. j. giustini, a. a. petryk, s. m. cassim, j. a. tate, i. baker, p. j. hoopes. magnetic nanoparticle hyperthermia in cancer treatment. nano life 2010 ; 01 : 17. - d. ghosh, y. lee, s. thomas, a. g. kohli, d. s. yun, a. m. belcher, k. a. kelly. m13 - templated magnetic nanoparticles for targeted in vivo imaging of prostate cancer. nat. nanotechnol. 2012 ; 7 ( 10 ) : 677 β 82. - add more references as deem appropriate 11 / 29 from professor angela belcher : - look at nature nano belcher lab paper - need to do very good characterization of materials using tem, elemental analysis, etc.
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subdomain_quantum_thermodynamics
| 0.535159
| 345
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:02670295-3a47-4d18-b098-38a53e1f91ab>
| 3
| 0.5
|
2025-12-19T07:35:33.386144
|
sleep apnea is a condition in which breathing is repeatedly interrupted during sleep. the time period for which the breathing stops or decreases is usually between 10 and 30 seconds. when these episodes occur repeatedly, sleep apnea can seriously disrupt the quality of sleep. there are three types of respiratory events : - obstructive apnea β caused by a temporary, partial, or complete blockage of the airway - central apnea β caused by a temporary failure to make an effort to breathe - mixed apnea β combination of the first two types these factors increase your chance of developing sleep apnea. tell your doctor if you have any of these risk factors : - sex : male - large neck circumference - age : middle to older age - family history of apnea structural abnormalities of the nose, throat, or other part of the respiratory tract. examples include : - severely enlarged tonsils - deviated nasal septum - medicines : sedatives and sleeping aids - alcohol consumption - fatigue and sleepiness during waking hours - loud snoring - breathing that stops during the night ( noticed by the partner ) - repeated waking at night - unrefreshing sleep - morning headaches - poor concentration or problems with memory - irritability or short temper people with chronic untreated sleep apnea may be at risk for : an overnight sleep study is used to help diagnose sleep apnea. overnight sleep study ( polysomnography ) this test helps detect the presence and severity of sleep apnea. during sleep, it measures your : - eye and muscle movements - brain activity ( electroencephalogram ) - heart rate - breathing ( pattern and depth ) - percent saturation of your red blood cells with oxygen there are a number of treatment options for sleep apnea, including : - lose weight if you are overweight. - avoid using sedatives, sleeping pills, alcohol, and nicotine, which tend to make the condition worse. - try sleeping on your side instead of your back. - place pillows strategically so you are as comfortable as possible. - for daytime sleepiness, practice safety measures, such as avoiding driving or operating potentially hazardous equipment. continuous positive airway pressure ( cpap ) entails wearing a mask over your nose and / or mouth during sleep. an air blower forces enough constant and continuous air through your air passages to prevent the tissues from collapsing and blocking the airway. in some cases, dental appliances that help keep the tongue or jaw in a more forward position may help. in some
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subdomain_quantum_optics
| 0.521951
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:da610566-65f7-4f92-a0b9-cbf818d8ece0>
| 0
| 0.5
|
2025-12-19T07:35:33.389369
|
we had a running joke in science ed that kids get so overexposed to discrepant events involving density and air pressure that they tend to try to explain anything and everything they don ' t understand with respect to science in terms of those two concepts. why do we have seasons? ummm... air pressure? why did dr. smith use that particular research design? ummm... density? i think we need another catch - all explanation. i suggest index of refraction. to simplify greatly, index of refraction describes the amount of bending a light ray will undergo as it passes from one medium to another ( it ' s also related to the velocity of light in both media, but i do want to keep this simple ). if the two media have significantly different indices, light passing from one to the other at an angle ( not perpendicularly, in which case there is no bending ) will be bent more than if indices of the two are similar. the first four data points are from hyperphysics, the final one from wikipedia... glass has a wide range of compositions and thus indices of refraction. water at 20 c : 1. 33 typical soda - lime glass : close to 1. 5 since glycerine and glass have similar ior, light passing from one to the other isn ' t bent ; as long as both are transparent and similarly colored, each will be effectively " invisible " against the other. so, why does it rain? umm... index of refraction? a bright moon impact 12 hours ago
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subdomain_quantum_optics
| 0.604974
| 317
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:7eeb7ef3-3122-42f0-86c8-01da8f3d7396>
| 0
| 0.5
|
2025-12-19T07:35:33.395291
|
an introduction to 127. 0. 0. 1 127. 0. 0. 1 is an ip address utilized for a looplock network connection. what does this mean? if a user tries to connect to this ip address, they will be sent back to their computer. the address is also known as a localhost. the localhost is the computer. how the localhost works if the command is relayed to the localhost, you would be hooked up to the system where the commands were sent out. for instance, suppose the computer is called " joker ". if you telnet from the joker computer to the localhost, a message will appear. it will attempt to hook up to the localhost is employed in lieu of the computer hostname to be linked to. this ip address is the most wisely used localhost address. however, you can actually use any ip address provided it starts with 127. this means 127. *. *. * can be used as a localhost. establishing a connection with the loopback address is similar to creating a connection with remote network computers. the only difference is you don ' t have to deal with network for this reason it is widely utilized by software developers. it is also used by system administrators. it is often used for testing programs and apps. if the connection is ipv4, the computer ' s loopback address will be the 127. *. *. *. the subnet mask is typically 255. 0. 0. 0. this ip addresses 127. *. *. *. are defined in rfc 330 as special - use ipv4 addresses. the 127. 0. 0. 0 / 8 block is defined as the net host loopback address. if a higher level protocol sends a datagram anywhere in the block, it will be looped in the host. this is typically implemented with the 127. 0. 0. 1 / 32 for looplock. however, addresses in the block must not be visible anywhere else in the network. there is also a localhost ipv6 version. in rfc 3513, it is defined as internet protocol version 6 ( ipv6 ) addressing architecture : : 1 / 128. more information about the localhost in simple terms, the localhost means the computer. it is the hostname allocated loopback network interface address. the name is likewise a domain name. this will help prevent confusion with the hostname definition. in ipv6, the loopback ip address
|
subdomain_quantum_cryptography
| 0.536148
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:0cfb12fb-ebfd-4e6a-8720-c551d7e97801>
| 0
| 0.5
|
2025-12-19T07:35:33.400827
|
| gallium metal is silver - white and melts at approximately body temperature ( wikipedia image ). | | atomic number : | | 31 | | atomic radius : | | 187 pm ( van der waals ) | | atomic symbol : | | ga | | melting point : | | 29. 76 Β°c | | atomic weight : | | 69. 72 | | boiling point : | | 2204 Β°c | | electron configuration : | | [ ar ] 4s23d104p1 | | oxidation states : | | 3 | from the latin word gallia, france ; also from latin, gallus, a translation of " lecoq, " a cock. predicted and described by mendeleev as ekaaluminum, and discovered spectroscopically by lecoq de boisbaudran in 1875, who in the same year obtained the free metal by electrolysis of a solution of the hydroxide in koh. gallium is often found as a trace element in diaspore, sphalerite, germanite, bauxite, and coal. some flue dusts from burning coal have been shown to contain as much 1. 5 percent gallium. it is one of four metals - - mercury, cesium, and rubidium - - which can be liquid near room temperature and, thus, can be used in high - temperature thermometers. it has one of the longest liquid ranges of any metal and has a low vapor pressure even at high temperatures. there is a strong tendency for gallium to supercool below its freezing point. therefore, seeding may be necessary to initiate solidification. ultra - pure gallium has a beautiful, silvery appearance, and the solid metal exhibits a conchoidal fracture similar to glass. the metal expands 3. 1 percent on solidifying ; therefore, it should not be stored in glass or metal containers, because they may break as the metal solidifies. high - purity gallium is attacked only slowly by mineral acids. gallium wets glass or porcelain and forms a brilliant mirror when it is painted on glass. it is widely used in doping semiconductors and producing solid - state devices such as transistors. magnesium gallate containing divalent impurities, such as mn + 2, is finding use in commercial ultraviolet - activated powder phosphors. gallium arsenide is capable of converting electricity directly into coherent light. gallium readily alloys with most metals, and has been used as a component in low - melting alloys.
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subdomain_quantum_thermodynamics
| 0.518091
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:317a0fc8-b8f1-4147-a9ac-f69a1f176048>
| 0
| 0.5
|
2025-12-19T07:35:33.408058
|
from oxford university press : there is a broad consensus among scholars that the idea of human rights was a product of the enlightenment but that a self - conscious and broad - based human rights movement focused on international law only began after world war ii. in this narrative, the nineteenth century ' s absence is conspicuous - - few have considered that era seriously, much less written books on it. but as jenny martinez shows in this novel interpretation of the roots of human rights law, the foundation of the movement that we know today was a product of one of the nineteenth century ' s central moral causes : the movement to ban the international slave trade. originating in england in the late eighteenth century, abolitionism achieved remarkable success over the course of the nineteenth century. martinez focuses in particular on the international admiralty courts, which tried the crews of captured slave ships. the courts, which were based in the caribbean, west africa, cape town, and brazil, helped free at least 80, 000 africans from captured slavers between 1807 and 1871. here then, buried in the dusty archives of admiralty courts, ships ' logs, and the british foreign office, are the foundations of contemporary human rights law : international courts targeting states and non - state transnational actors while working on behalf the world ' s most persecuted peoples - - captured west africans bound for the slave plantations of the americas. fueled by a powerful thesis and novel evidence, martinez ' s work will reshape the fields of human rights history and international human rights law. - forces us to fundamentally rethink the origins of human rights activism - filled with fascinating stories of captured slave ship crews brought to trial across the atlantic world in the nineteenth century - shows how the prosecution of the international slave trade was crucial to the development of modern international law
|
subdomain_quantum_cryptography
| 0.503523
| 353
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HuggingFaceFW/fineweb-edu
|
<urn:uuid:ec191471-6e59-4d54-afce-3997eab364e0>
| 0
| 0.5
|
2025-12-19T07:35:33.409761
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phantom phone calls ospri. net - alleged contact with the dead has occurred universally throughout history, taking various forms ; as dreams, waking visions and auditory hallucinations, either spontaneous or induced through trance. in many cultures, the spirits of the dead have been sought for their wisdom, advice and knowledge of the future. the dead also seem to initiate their own communication, using whatever means seem to be most effective. with the advent of electromagnetic technology, mysterious messages have been communicated by telegraph, wireless, phonographs and radio. a curious phenomenon of modern times is the communication via the telephone. phone calls from the dead seem to be random and occasional occurrences that happen without explanation. the great majority are exchanges between persons who shared a close emotional tie while both were living : spouses, parents and children, siblings, and occasionally friends and other relatives. most communications are " intention " calls, initiated by the deceased to impart a message, such as farewell upon death, a warning of impending danger, or information the living needs to carry out a task. for example, actress ida lupino ' s father, stanley, who died intestate in london during world war ii, called lupino six months after his death to relate information concerning his estate, the location of some unknown but important papers. some calls appear to have no other purpose than to make contact with the living ; many of these occur on emotionally charged " anniversary " days, such as mothers day or fathers day, a birthday or holiday. in a typical β anniversary β call, the dead may do nothing more than repeat a phrase over and over, such as " hello, mom, is that you? " persons who have received phone calls from the dead report that the voices are exactly the same as when the deceased was living, furthermore, the voice often uses pet names and words. the telephone usually rings normally, although some recipients say that the ring sounded flat and abnormal. in many cases, the connection is bad, with a great deal of static and line noise, and occasionally the faint voices of the other persons are heard, as though lines have been crossed. in many cases, the voice of the dead one is difficult to hear and grows fainter as the call goes on. sometimes, the voice just fades away but the line remains open, and the recipient hangs up after giving up on further communication. sometimes the call is terminated by the dead and the recipient hers the click of disengagement, other times, the line simply goes dead. the phantom phone calls typically
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subdomain_quantum_entanglement
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HuggingFaceFW/fineweb-edu
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<urn:uuid:c6d4bada-2535-41ff-b2c6-f0357a52e392>
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2025-12-19T07:35:33.416286
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line remains open, and the recipient hangs up after giving up on further communication. sometimes the call is terminated by the dead and the recipient hers the click of disengagement, other times, the line simply goes dead. the phantom phone calls typically occur when the recipient is in a passive state of mind. if the recipient knows the caller is dead, the shock is great and the phone call very brief, invariably, the caller terminates the call after a few seconds or minutes, or the line goes dead. if the recipient does not know the caller is dead, a lengthy conversation of up to 30 minutes or so may take place, during which the recipient is not aware of anything amiss. in a minority of cases, the call is placed person - to - person, long - distance with the assistance of a mysterious operator. checks with the telephone company later turn up no evidence of a call being places. similar phone calls from the dead are " intention " phone calls occurring between two living persons. such calls are much rarer than calls from the dead. in a typical " intention " call, the caller thinks about making the call but never does, the recipient nevertheless receives a call. in some cases, emergencies precipitate phantom calls, a surgeon is summoned by a nurse to the hospital to perform an emergency operation, a priest is called by a " relative " to give last rites to a dying man and so forth. some persons who claim to have had ufo encounters report receiving harassing phantom phone calls. the calls are received soon after the witness returns home, or within a day or two of the encounter, in many cases, the calls come before the witness has shared the experience with anyone, stranger still, they are often placed to unlisted phone numbers. the unidentified caller warns the witness not to talk and to " forget " what he or she saw. phone calls allegedly may be placed to the dead as well. the caller does not find out until sometime after the call that the person on the other end has been dead. in one such case, a woman dreamed of a female friend she had not seen for several years. in the disturbing dream, she witnessed the friend sliding down into a pool of blood. upon awakening, she worried that the dream was a portent of trouble, and called the friend. she was relieved when the friend answered. the friend explained that she had been in the hospital, had been released and was due to be readmitted in a few days. she demurred when the woman offered to visit
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subdomain_quantum_entanglement
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HuggingFaceFW/fineweb-edu
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<urn:uuid:c6d4bada-2535-41ff-b2c6-f0357a52e392>
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2025-12-19T07:35:33.417339
|
and called the friend. she was relieved when the friend answered. the friend explained that she had been in the hospital, had been released and was due to be readmitted in a few days. she demurred when the woman offered to visit, saying she would call later. the return call never came. the woman called her friend again, to be told by a relative that the friend has been dead for six months at the time the conversation took place. in several cases studied by researchers, the deceased callers make reference to an anonymous β they β and caution that there is little time to talk. the remarks imply that communication between the living and the dead is not only difficult, but not necessarily desirable. most phone calls from the dead occur within 24 hours of the death of the caller. most short calls come from those who have been dead seven days or less : most lengthy calls come from those who have been dead several months. one of the longest death - intervals on record is two years. in a small number of cases, the callers are strangers who say they are calling on behalf of a third party, whom the recipient later discovered is dead. several theories exist as to the origin of phantom phone calls. ( 1 ) they are indeed placed by the dead, who somehow manipulate the telephone mechanisms and circuitry : ( 2 ) they are deceptions of elemental - type spirits who enjoy playing tricks on the living : ( 3 ) they are psychokinetic acts caused subconsciously by the recipient, whose intense desire to communicate with the dead creates a type of hallucinatory experience : ( 4 ) they are entirely fantasy created by the recipient. for the most part, phantom phone calls are not seriously regarded by parapsychologists. in the early 20th century, numerous devices were built by investigators in hopes of capturing ghostly voices : many of them were modifications of the telegraph and wireless. thomas alva edison, whose parents were spiritualists, believed that a telephone could be invented that would connect the living to the dead. he verified that he was working on such a device, but apparently it never was completed before his death. " psychic telephone " experiments were conducted in the 1940 ' s in england and america. interest in the phenomenon waned until the 1960 β s, following the findings of konstantin raudive that ghostly voices could be captured on electromagnetic tape.
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subdomain_quantum_entanglement
| 0.529052
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HuggingFaceFW/fineweb-edu
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<urn:uuid:c6d4bada-2535-41ff-b2c6-f0357a52e392>
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2025-12-19T07:35:33.418280
|
researchers at ut southwestern medical center have found that fluctuations in internal body temperature regulate the body ' s circadian rhythm, the 24 - hour cycle that controls metabolism, sleep and other bodily functions. a light - sensitive portion of the brain called the suprachiasmatic nucleus ( scn ) remains the body ' s " master clock " that coordinates the daily cycle, but it does so indirectly, according to a study published by ut southwestern researchers in the oct. 15 issue of science. the scn responds to light entering the eye, and so is sensitive to cycles of day and night. while light may be the trigger, the ut southwestern researchers determined that the scn transforms that information into neural signals that set the body ' s temperature. these cyclic fluctuations in temperature then set the timing of cells, and ultimately tissues and organs, to be active or inactive, the study showed. scientists have long known that body temperature fluctuates in warm - blooded animals throughout the day on a 24 - hour, or circadian, rhythm, but the new study shows that temperature actually controls body cycles, said dr. joseph takahashi, chairman of neuroscience at ut southwestern and senior author of the study. " small changes in body temperature can send a powerful signal to the clocks in our bodies, " said dr. takahashi, an investigator with the howard hughes medical institute. " it takes only a small change in internal body temperature to synchronize cellular ' clocks ' throughout the body. " daily changes in temperature span only a few degrees and stay within normal healthy ranges. this mechanism has nothing to do with fever or environmental temperature, dr. takahashi said. this system might be a modification of an ancient circadian control system that first developed in other organisms, including cold - blooded animals, whose daily biological cycles are affected by external temperature changes, dr. takahashi said. " circadian rhythms in plants, simple organisms and cold - blooded animals are very sensitive to temperature, so it makes sense that over the course of evolution, this primordial mechanism could have been modified in warm - blooded animals, " he said. in the current study, the researchers focused on cultured mouse cells and tissues, and found that genes related to circadian functions were controlled by temperature fluctuations. scn cells were not temperature - sensitive, however. this finding makes sense, dr. takahashi said, because if the scn, as the master control mechanism, responded to temperature cues, a disruptive feedback loop could result, he said. explore further : now we know why old scizoph
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subdomain_quantum_thermodynamics
| 0.563179
| 512
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HuggingFaceFW/fineweb-edu
|
<urn:uuid:896eff09-96fc-4a88-806f-0afe2beec059>
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2025-12-19T07:35:33.420985
|
major section : break - rewrite example : ( brr @ : target ) ; the term being rewritten ( brr @ : unify - subst ) ; the unifying substitutionwhere general form : ( brr @ : symbol ) : symbolis one of the following keywords. those marked with * probably require an implementor ' s knowledge of the system to use effectively. they are supported but not well documented. more is said on this topic following the table. : symbol ( brr @ : symbol ) - - - - - - - - - - - - - - - - - - - - - - - - - - - - in general : target the term to be rewritten. this term is an instantiation of the left - hand side of the conclusion of the rewrite - rule being broken. this term is in translated form! thus, if you are expecting ( equal x nil ) - - and your expectation is almost right - - you will see ( equal x ' nil ) ; similarly, instead of ( cadr a ) you will see ( car ( cdr a ) ). in translated forms, all constants are quoted ( even nil, t, strings and numbers ) and all macros are expanded. : unify - subst the substitution that, when applied to : target, produces the left - hand side of the rule being broken. this substitution is an alist pairing variable symbols to translated (! ) terms. : wonp t or nil indicating whether the rune was successfully applied. ( brr @ : wonp ) returns nil if evaluated before : evaling the rule. : rewritten - rhs the result of successfully applying the rule or else nil if ( brr @ : wonp ) is nil. the result of successfully applying the rule is always a translated (! ) term and is never nil. : failure - reason some non - nil lisp object indicating why the rule was not applied or else nil. before the rule is : evaled, ( brr @ : failure - reason ) is nil. after : evaling the rule, ( brr @ : failure - reason ) is nil if ( brr @ : wonp ) is t. rather than document the various non - nil objects returned as the failure reason, we encourage you simply to evaluate ( brr @ : failure - reason ) in the contexts of interest. alternatively, study the acl2 function tilde -
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subdomain_quantum_optics
| 0.556991
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:460fe123-8906-4320-9cc8-f581b79ced1f>
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2025-12-19T07:35:33.426392
|
t. rather than document the various non - nil objects returned as the failure reason, we encourage you simply to evaluate ( brr @ : failure - reason ) in the contexts of interest. alternatively, study the acl2 function tilde - @ - failure - reason - phrase. : lemma * the rewrite rule being broken. for example, ( access rewrite - rule ( brr @ : lemma ) : lhs ) will return the left - hand side of the conclusion of the rule. : type - alist * a display of the type - alist governing : target. elements on the displayed list are of the form ( term type ), where term is a term and type describes information about term assumed to hold in the current context. the type - alist may be used to determine the current assumptions, e. g., whether a is a consp. : ancestors * a stack of frames indicating the backchain history of the current context. the theorem prover is in the process of trying to establish each hypothesis in this stack. thus, the negation of each hypothesis can be assumed false. each frame also records the rules on behalf of which this backchaining is being done and the weight ( function symbol count ) of the hypothesis. all three items are involved in the heuristic for preventing infinite backchaining. exception : some frames are ` ` binding hypotheses ' ' ( equal var term ) or ( equiv var ( double - rewrite term ) ) that bind variable var to the result of rewriting term. : gstack * the current goal stack. the gstack is maintained by rewrite and is the data structure printed as the current ` ` path. ' ' thus, any information derivable from the : path brr command is derivable from gstack. for example, from gstack one might determine that the current term is the second hypothesis of a certain rewrite rule. brr @ - expressionsare used in break conditions, the expressions that determine whether interactive breaks occur when monitored runes are applied. see monitor. for example, you might want to break only those attempts in which one particular term is being rewritten or only those attempts in which the binding for the variable ais known to be a consp. such conditions can be expressed using acl2 system functions and the information provided by brr @. unfortunately, digging some of this information out of the internal data structures may be awkward or may, at least
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subdomain_quantum_cryptography
| 0.589832
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:460fe123-8906-4320-9cc8-f581b79ced1f>
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2025-12-19T07:35:33.427422
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step - by - step instructions for activities like folding paper airplanes is testament to the generalized longing for play ' s good old days. so were the questions after stuart brown ' s library talk ; one woman asked how her children will learn trust, empathy and social skills when their most frequent playing is done online. brown told her that while video games do have some play value, a true sense of ' ' interpersonal nuance ' ' can be achieved only by a child who is engaging all five senses by playing in the three - dimensional world. this is part of a larger conversation americans are having about play. parents bobble between a nostalgia - infused yearning for their children to play and fear that time spent playing is time lost to more practical pursuits. alarming headlines about u. s. students falling behind other countries in science and math, combined with the ever - more - intense competition to get kids into college, make parents rush to sign up their children for piano lessons and test - prep courses instead of just leaving them to improvise on their own ; playtime versus r? m? uilding. discussions about play force us to reckon with our underlying ideas about childhood, sex differences, creativity and success. do boys play differently than girls? are children being damaged by staring at computer screens and video games? are they missing something when fantasy play is populated with characters from hollywood ' s imagination and not their own? most of these issues are too vast to be addressed by a single field of study ( let alone a magazine article ). but the growing science of play does have much to add to the conversation. armed with research grounded in evolutionary biology and experimental neuroscience, some scientists have shown themselves eager - - at times perhaps a little too eager - - to promote a scientific argument for play. they have spent the past few decades learning how and why play evolved in animals, generating insights that can inform our understanding of its evolution in humans too. they are studying, from an evolutionary perspective, to what extent play is a luxury that can be dispensed with when there are too many other competing claims on the growing brain, and to what extent it is central to how that brain grows in the first place. scientists who study play, in animals and humans alike, are developing a consensus view that play is something more than a way for restless kids to work off steam ; more than a way for chubby kids to burn off calories ; more than a frivolous luxury. play, in their view, is a central part of neurological growth and development -
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subdomain_quantum_gravity
| 0.535779
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HuggingFaceFW/fineweb-edu
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<urn:uuid:316c7af5-14e1-4d0b-9576-753e17ef2cc5>
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2025-12-19T07:35:33.493621
|
buildings, equipment, intangible assets ( like patents ) | liabilities | | liabilities are creditors ' claims for funds, usually because they have provided funds, or goods and services, to the firm. | examples : accounts payable, unearned income, notes payable, buildings, accrued salaries | shareholders ' equity | | shareholders ' equity shows the amounts of funds owners have provided and, in parallel, their claims on the assets of a firm. | examples : common stock, contributed capital, retained earnings | what are the separate sections on a balance sheet ( balance sheet classification ) | | 1. current assets represent assets that a firm expects to turn into cash, or sell, or consume within approximately one year from the date of the balance sheet ( i. e., accounts receivable and inventory ). | 2. current liabilities represent obligations a firm expects to pay within one year ( i. e., accounts payable and salaries payable ). 3. non - current assets are typically held and used for several years ( i. e., land, buildings, equipment, patents, long - term security investments ). 4. noncurrent liabilities and shareholders ' equity are sources of funds where the supplier of funds does not expect to receive them all back within the next year. | income statement | | 1. sometimes called the statement of profit and loss by firms applying ifrs | 2. provides information on profitability 3. may use the terms net income, earnings, and profit interchangeably 4. reports amounts for a period of time 5. typically one year 6. is represented by the basic income equation : net income = revenues - expenses | revenues | | ( also known as sales, sales revenue, or turnover, a term used by some firms reporting under ifrs ) measure the inflows of assets ( or reductions in liabilities ) from selling goods and providing services to customers. | | expenses | | measure the outflow of assets ( or increases in liabilities ) used in generating revenues. | | relationship between the balance sheet and the income statement | | 1. the income statement links the balance sheet at the beginning of the period with the balance sheet at the end of the period. | 2. retained earnings is increased by net income and decreased by dividends. | statement of cash flows | | the statement of cash flows ( also called the | cash flow statement ) reports information about cash generated from or used by : 2. investing, and 3. financing activities during specified time periods
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subdomain_quantum_optics
| 0.519538
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HuggingFaceFW/fineweb-edu
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<urn:uuid:03b12dbf-26a3-4290-b6e6-e08368916e2a>
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2025-12-19T07:35:33.524204
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or sales : | ( common income statement terms ) | assets received in exchange for goods sold and services rendered. | | cost of goods sold : | ( common income statement terms ) | the cost of products sold. | | selling, general, and administrative ( sg & a ) : | ( common income statement terms ) | costs incurred to sell products / services as well as costs of administration. | | research and development ( r & d ) expense : | ( common income statement terms ) | costs incurred to create / develop new products, processes, and services. | | interest income : | ( common income statement terms ) | income earned on amounts lent to others or from investments in interest - yielding securities. | | unique relationships exist between the balance sheet and the income statement | | important account differences | | 1. balance sheet accounts are permanent accounts in the sense that they remain open, with nonzero balances, at the end of the reporting period. | 2. in contrast, income statement accounts are temporary accounts in the sense that they start a period with a zero balance, accumulate information during the reporting period, and have a zero balance at the end of the reporting period. | the financial statement relationships can be summarized as : | - after preparing the end - of - period income statement, the accountant transfers the balance in each temporary revenue and expense account to the retained earnings account. - this procedure is called closing the revenue and expense accounts. after transferring to retained earnings, each revenue and expense account is ready to begin the next period with a zero balance. | expense and revenue transactions | | dividend declaration and payment | | issues of capital stock | | posting | | 1. after each transaction is recognized by a journal entry, the information is transferred in the accounting system via an activity known as posting. | 2. the balance sheet ledger accounts ( or permanent accounts ) where these are posted begin each period with a balance equal to the ending balance of the previous period. 3. the income statement ledger accounts ( or temporary accounts ) have zero beginning balances. | adjusting entries | | there are some journal entries that are not triggered by a transaction or exchange. | - rather, journal entries known as adjusting entries, result from the passage of time at the end of an accounting period or are used to correct errors ( more commonly known as correcting entries ). | four basic types of adjusting entries | | 1. unearned revenues | | closing process | | 1. after adjusting and correcting entries are made, the income statement can be
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subdomain_quantum_optics
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HuggingFaceFW/fineweb-edu
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<urn:uuid:03b12dbf-26a3-4290-b6e6-e08368916e2a>
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2025-12-19T07:35:33.529169
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intel demonstrated a wireless electric power system that could revolutionize modern life by eliminating chargers, wall outlets and eventually batteries all together by 2050. intel chief technology officer justin rattner demonstrated a wireless energy resonant link at intel β s 2008 developer β s forum. during the demo electricity was sent wirelessly to a lamp on stage, lighting a 60 watt bulb that uses more power than a typical laptop computer. most importantly, the electricity was transmitted without zapping anything or anyone that got between the sending and receiving units. β the trick with wireless power is not can you do it ; it β s can you do it safely and efficiently, β according to intel researcher josh smith. β it turns out the human body is not affected by magnetic fields ; it is affected by elective fields. so what we are doing is transmitting energy using the magnetic field not the electric field. β examples of potential applications include airports, offices or other buildings that could be rigged to supply power to laptops, mobile telephones or other devices toted into them. the technology could also be built into plugged in computer components, such as monitors, to enable them to broadcast power to devices left on desks or carried into rooms, according to mr. smith. - duracell, energizer, texas instruments and motorola mobility in attendance at the international wireless power summit ( prweb. com ) - british start - up working to bring wireless charging to the racetrack ( wheels. blogs. nytimes. com )
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subdomain_quantum_thermodynamics
| 0.55811
| 303
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HuggingFaceFW/fineweb-edu
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<urn:uuid:43d4b460-a138-4381-addd-d0464250f94f>
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2025-12-19T07:35:33.531315
|
by roger fox i doubt the keystone project is even a real long term goal by transcanada,. certainly in the big picture keystone is only a single chapter in a much larger book. if you read this diary you will risk information overload, you will be offered numerous disparate data points that at first glance may seem unconnected. you will need to digest all the information offered, and then analyze. crude is is classified by the american petroleum institute ( api ) into light, medium, heavy and extra heavy crudes, by api gravity. if its api gravity is greater than 10, it is lighter and floats on water ; if less than 10, it is heavier and sinks. the albert tar sands contain crudes of api 10 or less that is called extra heavy or bitumen. heavy oil is defined as having an api gravity below 22. 3, medium oil is defined as having an api gravity between 22. 3 Β°api and 31. 1 Β°api, light crude oil is defined as having an api gravity higher than 31. 1. at a production rate of 3 million barells a day the tar sands can last for 170 years. this would also mean a hole in the ground visible from orbit. the keystone pipeline is only one of a couple of handfuls of pipeline proposals over the last decade in the western us, canada and alaska. alaskan nat gas is largely unexploited, and is used locally on the north slope. its estimated that 70 trillion cubic feet of nat gas can be found in alaska, a lot of it in the north slope area. there are at least 3 major proposals for nat gas pipelines from the north slope area and the adjacent mackenzie river delta in canada. 2 of these projects point right at alberta. transcanada and exxon mobil are partnered in the alaska gas pipeline proposal that will directly link nat gas production in the north slope of alaska thru alberta to the us mid west. this project may be the same as the denali proposal, and was reintroduced to thesenate in feb, of 2011. there also at least 2 variations. additionally there is the dempster lateral. - > next page : follow the routes south
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subdomain_quantum_gravity
| 0.536738
| 443
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HuggingFaceFW/fineweb-edu
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<urn:uuid:ba49b9f2-b352-4b64-9909-4785d5b6527b>
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2025-12-19T07:35:33.534625
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w hy is it important for scientists to contribute to science education? our nation has failed to meet important educational challenges, and our children are ill prepared to respond to the demands of today? s world. results of the third international mathematics and science study ( timss ) - - and its successor, timss - r - - show that the relatively strong international performance of u. s. 4th graders successively deteriorates across 8th - and 12th - grade cohorts. related studies indicate that u. s. prek - 12 curricula lack coherence, depth, and continuity and cover too many topics superficially. by high school, unacceptably low numbers of students show motivation or interest in enrolling in physics ( only one - quarter of all students ) or chemistry ( only one - half ). we are rapidly approaching universal participation at the postsecondary level, but we still have critical science, technology, engineering, and mathematics ( stem ) workforce needs and too few teachers who have studied science or mathematics. science and engineering degrees as a percentage of the degrees conferred each year have remained relatively constant at about 5 %. in this group, women and minorities are gravely underrepresented. the consequences of these conditions are serious. the u. s. department of labor estimates that 60 % of the new jobs being created in our economy today will require technological literacy, yet only 22 % of the young people entering the job market now actually possess those skills. by 2010, all jobs will require some form of technological literacy, and 80 % of those jobs haven? t even been created yet. we must prepare our students for a world that we ourselves cannot completely anticipate. this will require the active involvement of scientists and engineers. how is nsf seeking to encourage scientists to work on educational issues? the nsf strategic plan includes two relevant goals : to develop " a diverse, internationally competitive, and globally engaged workforce of scientists, engineers, and well - prepared citizens " and to support " discovery across the frontiers of science and engineering, connected to learning, innovation, and service to society. " to realize both of these goals, our nation? s scientists and engineers must care about the educational implications of their work and explore educational issues as seriously and knowledgeably as they do their research questions. the phrase " integration of research and education " conveys two ideas. first, good research generates an educational asset, and we must effectively use that asset. second, we need to encourage more scientists and engineers to pursue research careers that focus
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subdomain_quantum_field_theory
| 0.524247
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:21bc3a09-e45d-497b-add1-4880324aff25>
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2025-12-19T07:35:33.552735
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research questions. the phrase " integration of research and education " conveys two ideas. first, good research generates an educational asset, and we must effectively use that asset. second, we need to encourage more scientists and engineers to pursue research careers that focus on teaching and learning within their own disciplines. all proposals submitted to nsf for funding must address two merit criteria : intellectual merit and broader impacts. in everyday terms, our approach to evaluating the broader impact of proposals is built on the philosophy that scientists and engineers should pay attention to teaching and value it, and that their institutions should recognize, support, and reward faculty, as well as researchers in government and industry, who take their role as educators seriously and approach instruction as a scholarly act. we think of education very broadly, including formal education ( k - graduate and postdoctoral study ) and informal education ( efforts to promote public understanding of science and research outside the traditional educational environment ). what does it mean to take education seriously and explore it knowledgeably? any scholarly approach to education must be intentional, be based on a valid body of knowledge, and be rigorously assessed. that is, our approach to educational questions must be a scholarly act. nsf actively invests in educational reform and models that encourage scientists and engineers to improve curriculum, teaching, and learning in science and mathematics at all levels of the educational system from elementary school to graduate study and postdoctoral work. we recognize that to interest faculty and practicing scientists and engineers in education, we must support research that generates convincing evidence that changing how we approach the teaching of science and mathematics will pay off in better learning and deeper interest in these fields. here are a few of the most recent efforts to stimulate interest in education that might be of interest to next wave readers. ( for more information, go to the nsf education and human resources directorate ' s web site. ) the gk - 12 program supports fellowships and training to enable stem graduate students and advanced undergraduates to serve in k - 12 schools as resources in stem content and applications. outcomes include improved communication and teaching skills for the fellows, increased content knowledge for prek - 12 teachers, enriched prek - 12 student learning, and stronger partnerships between higher education and local schools. the centers for learning and teaching ( clt ) program is a " comprehensive, research - based effort that addresses critical issues and national needs of the stem instructional workforce across the entire spectrum of formal and informal education. " the goal of the clt program is to support the development of new approaches to the assessment of learning, research on learning
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subdomain_quantum_field_theory
| 0.571394
| 512
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HuggingFaceFW/fineweb-edu
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<urn:uuid:21bc3a09-e45d-497b-add1-4880324aff25>
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2025-12-19T07:35:33.553906
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- based effort that addresses critical issues and national needs of the stem instructional workforce across the entire spectrum of formal and informal education. " the goal of the clt program is to support the development of new approaches to the assessment of learning, research on learning within the disciplines, the design and development of effective curricular materials, and research - based approaches to instruction - - and through this work to increase the number of people who do research on education in the stem fields. this year ( fy 02 ) we are launching some prototype higher education centers to reform teaching and learning in our nation ' s colleges and universities through a mix of research, faculty development and exploration of instructional practices that can promote learning. like other nsf efforts, the centers incorporate a balanced strategy of attention to people, ideas and tools. we hope to encourage more science and engineering faculty to work on educational issues in both k - 12 and in postsecondary education. if you are interested in these issues and want to pursue graduate or postdoctoral study, or want to develop a research agenda on learning in stem fields, find the location and goals of the currently funded centers and also check later this summer to find out which higher education clt prototypes are funded. the following solicitations all involve the integration of research and education as well as attention to broadening participation in stem careers : the science, technology, engineering, and mathematics talent expansion program ( step ) program seeks to increase the number of students ( u. s. citizens or permanent residents ) pursuing and receiving associate or baccalaureate degrees in established or emerging fields within stem. the faculty early career development ( career ) program recognizes and supports the early career development activities of those teacher - scholars who are most likely to become the academic leaders of the 21st century. the course, curriculum, and laboratory improvement ( ccli ) program seeks to improve the quality of stem education for all students and targets activities affecting learning environments, course content, curricula, and educational practices. ccli offers three tracks : educational materials development, national dissemination, and adaptation and implementation. the integrative graduate education and research training ( igert ) program addresses the challenges of preparing ph. d. scientists and engineers with the multidisciplinary backgrounds and the technical, professional, and personal skills needed for the career demands of the future. the vertical integration of research and education in the mathematical sciences ( vigre ) program supports institutions with ph. d. - granting departments in the mathematical sciences in carrying out innovative educational programs, at all levels, that are integrated with
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subdomain_quantum_gravity
| 0.532784
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:21bc3a09-e45d-497b-add1-4880324aff25>
| 2
| 0.5
|
2025-12-19T07:35:33.554926
|
file compression is to perform some algorithm on the file that reduces it in size but the reverse of the algorithm will return it to its original form. in data files, the compression and decompression must be lossless which means that the data must be returned to its exact form. there are various methods to do this : some hardware implementations and some software. the most popular ones that are implemented in hardware usually use a limpel - ziv algorithm to look for repeating sequences over a set span of data ( the run ) and replace that with special identifying information. compression does save space but may take extra time ( latency ). video and music data are typically already compressed. the compression rates are usually very high because of the data and the fact that a lossy compression algorithm is used. it can be lossy ( meaning that all bits may not be decompressed exactly ) because it won ' t be noticeable with video or music. zip files are the result of software compression. another compression round on already compressed data will probably not yield any substantial gain. evaluator group, inc. editor ' s note : do you agree with this expert ' s response? if you have more to share, post it in our storage networking forum at http : / / searchstorage. discussions. techtarget. com / webx? 50 @ @. ee83ce4 or e - mail us directly at firstname. lastname @ example. org. this was first published in december 2001
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subdomain_quantum_cryptography
| 0.558616
| 302
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:89cf800c-2b77-4614-98f0-40e3877e109f>
| 0
| 0.5
|
2025-12-19T07:35:33.556547
|
classroom activities for teaching sedimentary geologythis collection of teaching materials allows for the sharing of ideas and activities within the community of geoscience teachers. do you have a favorite teaching activity you ' d like to share? please help us expand this collection by contributing your own teaching materials. subject : sedimentary geology results 1 - 4 of 4 matches chemical and physical weathering field and lab experiment : development and testing of hypotheses part of activities lisa greer, washington and lee university this exercise combines an integrated field and laboratory experiment with a significant scientific writing assignment to address chemical and physical weathering processes via hypothesis development, experimental... demystifying the equations of sedimentary geology part of activities larry lemke, wayne state university this activity includes three strategies to help students develop a deeper comfort level and stronger intuitive sense for understanding mathematical expressions commonly encountered in sedimentary geology. each can... digital sandstone tutorial part of activities kitty milliken, university of texas at austin, the the tutorial petrographic image atlas is designed to give students more exposure to petrographic features than they can get during organized laboratory periods. red rock and concretion models from earth to mars : teaching diagenesis part of activities margie chan, university of utah this activity teaches students concepts of terrestrial diagenesis ( cementation, fluid flow, porosity and permeability, concretions ) and encourages them to apply those concepts to new or unknown settings, including...
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subdomain_quantum_gravity
| 0.527605
| 294
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:f4b8146e-83a2-43e4-8f2c-b3c235ae8afb>
| 0
| 0.5
|
2025-12-19T07:35:33.566899
|
- exam wrappers. as david thompson describes the process, " exam wrappers required students to reflect on their performance before and after seeing their graded tests. " the first four questions, completed just prior to receiving their graded test, asked students to report the time they spent preparing for the test, their methods of preparation, and their predicted test grade. after reviewing their graded test, students completed the final three reflection questions, including a categorization of test mistakes and a list of changes to implement in preparation for the next test. thompson then collected and made copies of the wrappers returned them to the students several days later, reminding them to consider what they planned to do differently or the same in preparation for the upcoming test. thompson reports that each reflection exercise required only 8 - 10 minutes of class time. clara hardy and others also describes uses exam wrappers. - reading reflections. as karl wirth writes, reading reflections, effectively outlined by david bressoud ( 2008 ), are designed to address some of the challenges students face with college - level reading assignments. students submit online reading reflections ( e. g., using moodle or blackboard ) after completing each reading assignment and before coming to class. in each reflection, students summarize the important concepts of the reading and describe what was interesting, surprising, or confusing to them. the reading reflections not only encourage students to read regularly before class, but they also promote content mastery and foster student development of monitoring, self - evaluation, and reflection skills. for the instructor, reading reflections facilitate " just - in - time " teaching and provide invaluable insights into student thinking and learning. according to wirth, expert readers are skilled at using a wide range of strategies during all phases of reading ( e. g., setting goals for learning, monitoring comprehension during reading, checking comprehension, and self - reflection ), but most college instruction simply assumes the mastery of such metacognitive skills. - knowledge surveys. many members of the group were influenced by karl wirth ' s work on " knowledge surveys " as a central strategy for helping students think about their thinking. knowledge surveys involve simple self - reports from students about their knowledge of course concepts and content. in knowledge surveys, students are presented with different facets of course content and are asked to indicate whether they know the answer, know some of the answer, or don ' t know the answer. faculty can use these reports to gauge how confident students feel in their understanding of course material at the beginning or end of a course, before
|
subdomain_quantum_mechanics
| 0.510529
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:9d6abf05-e21c-4917-ab95-cb9f3fd306aa>
| 0
| 0.5
|
2025-12-19T07:35:33.570445
|
bottom waters, takes the form of a spiral or helix. more than 95 per cent of the river ' s energy is lost in turbulence and friction. the direction of the flow of the thames is therefore quixotic. it might be assumed that it would move eastwards, but it defies any simple prediction. it flows north - west above henley and at teddington, west above abingdon, south from cookham and north above marlow and kingston. this has to do with the variegated curves of the river. it does not meander like the euphrates, where according to herodotus the voyager came upon the same village three times on three separate days, but it is circuitous. it specialises in loops. it will take the riparian traveller two or three times as long to cover the same distance as a companion on the high road. so the thames teaches you to take time, and to view the world from a different vantage. the average " fall " or decline of the river from its beginning to its end is approximately 17 to 21 inches ( 432 to 533 mm ) per mile. it follows gravity, and seeks out perpetually the simplest way to the sea. it falls some 600 feet ( 183 m ) from source to sea, with a relatively precipitous decline of 300 feet ( 91. 5 m ) in the first 9 miles ; it falls 100 ( 30. 4 m ) more in the next 11 miles, with a lower average for the rest of its course. yet averages may not be so important. they mask the changeability and idiosyncrasy of the thames. the mean width of the river is given as 1, 000 feet ( 305 m ), and a mean depth of 30 feet ( 9 m ) ; but the width varies from 1 or 2 feet ( 0. 3 to 0. 6 m ) at trewsbury to 51u2 miles at the nore. the tide, in the words of tennyson, is that which " moving seems asleep, too full for sound and foam. " on its flood inward it can promise benefit or danger ; on its ebb seaward it suggests separation or adventure. it is one general movement but it comprises a thousand different streams and eddies ; there are opposing streams, and high water is not necessarily the same thing as high tide. the water will sometimes begin to fall before the tide is over. the average speed of the tide lies between 1 and 3 knots ( 1. 15 and 3. 45 miles
|
subdomain_quantum_thermodynamics
| 0.508182
| 512
|
HuggingFaceFW/fineweb-edu
|
<urn:uuid:c8589dab-6a33-4d56-9c69-99faf059b9e4>
| 1
| 0.5
|
2025-12-19T07:35:33.588043
|
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