Literatura científica selecionada sobre o tema "Propriété de Schur"

Les plantes alimentaires contiennent des principes actifs doués de diverses propriétés médicinales pouvant intervenir dans le traitement de nombreuses maladies. Cette étude est consacrée au recensement des plantes ayant des potentiels nutritionnel et thérapeutique dans la région Maritime du Togo, dans le but de la valorisation de ces plantes. De juin à septembre 2017, une enquête ethnobotanique, basée sur l’utilisation des interviews individuelles à l'aide d'un questionnaire semi-structuré, a été réalisée auprès de 101 Praticiens de la Médecine Traditionnelle. Au total 86 espèces végétales appartenant à 72 genres et 36 familles ont été identifiées. Les Fabaceae et les Solanaceae (7 espèces chacune) ont été les plus représentées. Les espèces les plus citées ont été Ocimum gratissimum L. (10,48%), Vernonia amygdalina Delile (6,71%), Lactuca taraxacifolia (Willd.) Schum. (6,08%) et Heliotropium indicum L. (5,66%). Les feuilles (77,85%), les fruits (5,63%) et les racines (4,26%) sont les organes les plus utilisées sur 799 recettes inventoriées. La principale forme galénique reste la sauce (51,19%) et le mode principal d’administration est la voie orale (90,74%). Concernant les maladies traitées, les affections du tube digestif sont au premier rang (43,80%) suivies par des affections cardiovasculaires (13,52%). Cette étude fournie une base de données sur des plantes ayant des potentiels nutritionnel et thérapeutique au Togo.Mots clés : Alicaments, potentiels nutritionnel et thérapeutique, sécurité alimentaire, Togo. English title: Ethnobotanical study of some food plants used in traditional medicine in the Maritime region of TogoFood plants contain active substances with various medicinal properties that can be used to treat many diseases. This study is devoted to the inventory of plants with nutritional and therapeutic potential in Maritime region of Togo, with the aim of promoting these plants. From June to September 2017, an ethnobotanical survey was conducted among 101 Traditional Medicine Practitioners through individual interviews using a semi-structured questionnaire. A total of 86 plants species belonging to 72 genera and 36 families were identified. Fabaceae and Solanaceae (7 species each) were the most represented. The most cited species were Ocimum gratissimum L. (10.48%), Vernonia amygdalina Delile (6.71%), Lactuca taraxacifolia (Willd.) Schum. (6.08%) and Heliotropium indicum L. (5.66%). The leaves (77.85%), fruits (5.63%) and roots (4.26%) were the most plant parts used out of 799 inventoried recipes. The main dosage form remains the sauce (51.19%) and the main mode of administration is the oral route (90.74%). Regarding the treated diseases, the digestive disorders are in first place (43.80%), followed by cardiovascular diseases (13.52%). This study provides a database of plants with nutritional and therapeutic potential in Togo.Keywords: Food plants, nutritional and therapeutic potentials, food security, Togo.

International audience In the late 1930's Murnaghan discovered the existence of a stabilization phenomenon for the Kronecker product of Schur functions. For $n$ large enough, the values of the Kronecker coefficients appearing in the product of two Schur functions of degree $n$ do not depend on the first part of the indexing partitions, but only on the values of their remaining parts. We compute the exact value of n when this stable expansion is reached. We also compute two new bounds for the stabilization of a particular coefficient of such a product. Given partitions $\alpha$ and $\beta$, we give bounds for all the parts of any partition $\gamma$ such that the corresponding Kronecker coefficient is nonzero. Finally, we also show that the reduced Kronecker coefficients are structure coefficients for the Heisenberg product introduced by Aguiar, Ferrer and Moreira. Dans les années 30 Murnaghan a découvert une propriété de stabilité pour le produit de Kronecker de fonctions de Schur. En degré assez grand, les valeurs des coefficients qui aparaissent dans le produit de Kronecker de deux fonctions de Schur ne dépendent pas de la première part des partitions en indice, mais seulement des parts suivantes. Dans ce travail nous calculons la valeur exacte du degré à partir duquel ce développement stable est atteint. Nous calculons aussi deux nouvelles bornes supérieures pour la stabilisation d'un coefficient particulier d'un tel produit. Nous donnons en outre, pour $\alpha$ et $\beta$ fixés, des bornes supérieures pour toutes les parts des partition $\gamma$ rendant le coefficient de Kronecker d'indices $\alpha$, $\beta$, $\gamma$ non―nul. Finalement, nous identifions les coefficients de Kronecker réduits comme des constantes de structures pour le produit de Heisenberg de fonctions symétriques défini par Aguiar, Ferrer et Moreira.

International audience For each infinite series of the classical Lie groups of type $B$, $C$ or $D$, we introduce a family of polynomials parametrized by the elements of the corresponding Weyl group of infinite rank. These polynomials represent the Schubert classes in the equivariant cohomology of the corresponding flag variety. They satisfy a stability property, and are a natural extension of the (single) Schubert polynomials of Billey and Haiman, which represent non-equivariant Schubert classes. When indexed by maximal Grassmannian elements of the Weyl group, these polynomials are equal to the factorial analogues of Schur $Q$- or $P$-functions defined earlier by Ivanov. Pour chaque série infinie des groupe de Lie classiques de type $B$,$C$ ou $D$, nous présentons une famille de polynômes indexées par de éléments de groupe de Weyl correspondant de rang infini. Ces polynômes représentent des classes de Schubert dans la cohomologie équivariante des variétés de drapeaux. Ils ont une certain propriété de stabilité, et ils étendent naturellement des polynômes Schubert (simples) de Billey et Haiman, que représentent des classes de Schubert dans la cohomologie non-équivariante. Quand ils sont indexées par des éléments Grassmanniennes de groupes de Weyl, ces polynômes sont égaux à des analogues factorielles de fonctions $Q$ et $P$ de Schur, étudiées auparavant par Ivanov.

International audience We establish several properties of an algorithm defined by Mason and Remmel (2010) which inserts a positive integer into a row-strict composition tableau. These properties lead to a Littlewood-Richardson type rule for expanding the product of a row-strict quasisymmetric Schur function and a symmetric Schur function in terms of row-strict quasisymmetric Schur functions. Nous établissons plusieurs propriétés d'un algorithme défini par Mason et Remmel (2010), qui insère un entier positif dans un tableau dont la forme est une composition, avec ordre strict sur les lignes (row-strict). Ces propriétés conduisent à une règle de type Littlewood-Richardson pour étendre le produit d'une fonction de Schur quasi-symétrique "row-strict'' et d'une fonction de Schur symétrique en termes de fonctions de Schur quasi-symétriques "row-strict''.

International audience Noncommutative symmetric functions have many properties analogous to those of classical (commutative) symmetric functions. For instance, ribbon Schur functions (analogs of the classical Schur basis) expand positively in noncommutative monomial basis. More of the classical properties extend to noncommutative setting as I will demonstrate introducing a new family of noncommutative symmetric functions, depending on one parameter. It seems to be an appropriate noncommutative analog of the Hall-Littlewood polynomials. Les fonctions symétriques non commutatives ont de nombreuses propriétés analogues à celles des fonctions symétriques classiques (commutatives). Par exemple, les fonctions de Schur en rubans (analogues de la base de Schur classique) admettent des développements à coefficients positifs dans la base des monômes non commutatifs. La plupart des propriétés classiques s'étendent au cas non commutatif, comme je le montrerai en introduisant une nouvelle famille de fonctions symétriques non commutatives, dépendant d'un paramètre. Cette famille semble être un analogue non commutatif approprié de la famille des polynômes de Hall-Littlewood.

International audience Since every even power of the Vandermonde determinant is a symmetric polynomial, we want to understand its decomposition in terms of the basis of Schur functions. We investigate several combinatorial properties of the coefficients in the decomposition. In particular, I will give a recursive approach for computing the coefficient of the Schur function $s_μ$ in the decomposition of an even power of the Vandermonde determinant in $n+1$ variables in terms of the coefficient of the Schur function $s_λ$ in the decomposition of the same even power of the Vandermonde determinant in $n$ variables if the Young diagram of $μ$ is obtained from the Young diagram of $λ$ by adding a tetris type shape to the top or to the left. Comme toute puissance paire du déterminant de Vandermonde est un polynôme symétrique, nous voulons comprendre sa décomposition dans la base des fonctions de Schur. Nous allons étudier plusieurs propriétés combinatoires des coefficients de la décomposition. En particulier, nous allons donner une approche récursive pour le calcul du coefficient de la fonction de Schur $s_μ$ dans la décomposition d'une puissance paire du déterminant de Vandermonde en $n+1$ variables, en fonction du coefficient de la fonction de Schur $s_λ$ dans la décomposition de la même puissance paire du déterminant de Vandermonde en $n$ variables, lorsque le diagramme de Young de $μ$ est obtenu à partir du diagramme de Young de $λ$ par l'addition d'une forme de type tetris vers le haut ou vers la gauche.

International audience The Schur functions in superspace $s_\Lambda$ and $\overline{s}_\Lambda$ are the limits $q=t= 0$ and $q=t=\infty$ respectively of the Macdonald polynomials in superspace. We present the elementary properties of the bases $s_\Lambda$ and $\overline{s}_\Lambda$ (which happen to be essentially dual) such as Pieri rules, dualities, monomial expansions, tableaux generating functions, and Cauchy identities. Les fonctions de Schur dans le superespace $s_\Lambda$ et $\overline{s}_\Lambda$ sont les limites $q=t= 0$ et $q=t=\infty$ respectivement des polynômes de Macdonald dans le superespace. Nous présentons les propriétés élémentaires des bases $s_\Lambda$ et $\overline{s}_\Lambda$ (qui sont essentiellement duales l'une de l'autre) tels que les règles de Pieri, la dualité, le développement en fonctions monomiales, les fonctions génératrices de tableaux et les identités de Cauchy.

1. Make a list of things to do2. Copy list of things left undone from previous list3. Add items to list of new things needing to be done4. Add some of the things already done from previous list and immediately cross off so as to put off the feeling of an interminable list of never accomplishable tasks5. Finish writing list and sit back feeling an overwhelming sense of listlessnessIt started so well. Get up: make list: get on. But lists can breed listlessness. It can’t always be helped. The word “list” referring to a sequence of items comes from the Italian and French words for “strip”—as in a strip of material. The word “list” that you find in the compound “listlessness” comes from the old English word for pleasing (to list is to please and to desire). To be listless is to be without desire, without the desire to please. The etymologies of list and listless don’t correspond but they might seem to conspire in other ways. Oh, and by the way, ships can list when their balance is off.I list, like a ship, itemising my obligations to job, to work, to colleagues, to parenting, to family: write a reference for such and such; buy birthday present for eighty-year-old dad; finish article about lists – and so on. I forget to add to the list my necessary requirements for achieving any of this: keep breathing; eat and drink regularly; visit toilet when required. Lists make visible. Lists hide. I forget to add to my list all my worries that underscore my sense that these lists (or any list) might require an optimism that is always something of a leap of faith: I hope that electricity continues to exist; I hope my computer will still work; I hope that my sore toe isn’t the first sign of bodily paralysis; I hope that this heart will still keep beating.I was brought up on lists: the hit parade (the top one hundred “hit” singles); football leagues (not that I ever really got the hang of them); lists of kings and queens; lists of dates; lists of states; lists of elements (the periodic table). There are lists and there are lists. Some lists are really rankings. These are clearly the important lists. Where do you stand on the list? How near the bottom are you? Where is your university in the list of top universities? Have you gone down or up? To list, then, for some at least is to rank, to prioritise, to value. Is it this that produces listlessness? The sense that while you might want to rank your ten favourite films in a list, listing is something that is constantly happening to you, happening around you; you are always in amongst lists, never on top of them. To hang around the middle of lists might be all that you can hope for: no possibility of sudden lurching from the top spot; no urgent worries that you might be heading for demotion too quickly.But ranking is only one aspect of listing. Sometimes listing has a more flattening effect. I once worked as a cash-in-hand auditor (in this case a posh name for someone who counts things). A group of us (many of whom were seriously stoned) were bussed to factories and warehouses where we had to count the stock. We had to make lists of items and simply count what there was: for large items this was relatively easy, but for the myriad of miniscule parts this seemed a task for Sisyphus. In a power-tool factory in some unprepossessing town on the outskirts of London (was it Slough or Croydon or somewhere else?) we had to count bolts, nuts, washers, flex, rivets, and so on. Of course after a while we just made it up—guesstimates—as they say. A box of thousands of 6mm metal washers is a homogenous set in a list of heterogeneous parts that itself starts looking homogenous as it takes its part in the list. Listing dedifferentiates in the act of differentiating.The task of making lists, of filling-in lists, of having a list of tasks to complete encourages listlessness because to list lists towards exhaustiveness and exhaustion. Archives are lists and lists are often archives and archived. Those that work on lists and on archives constantly battle the fatigue of too many lists, of too much exhaustiveness. But could exhaustion be embraced as a necessary mood with which to deal with lists and archives? Might listlessness be something of a methodological orientation that has its own productivity in the face of so many lists?At my university there resides an archive that can appear to be a list of lists. It is the Mass-Observation archive, begun at the end of 1936 and, with a sizeable hiatus in the 1960s and 1970s, is still going today. (For a full account of Mass-Observation, see Highmore, Everyday Life chapter 6, and Hubble; for examples of Mass-Observation material, see Calder and Sheridan, and Highmore, Ordinary chapter 4; for analysis of Mass-Observation from the point of view of the observer, see Sheridan, Street, and Bloome. The flavour of the project as it emerges in the late 1930s is best conveyed by consulting Mass-Observation, Mass-Observation, First Year’s Work, and Britain.) It was begun by three men: the filmmaker Humphrey Jennings, the poet and sociologist Charles Madge, and the ornithologist and anthropologist-of-the-near Tom Harrisson. Both Jennings and Madge were heavily involved in promoting a form of social surrealism that might see buried forces in the coincidences of daily life as well as in the machinations and contingency of large political and social events (the abdication crisis, the burning of the Crystal Palace—both in late 1936). Harrisson brought a form of amateur anthropology with him that would scour football crowds, pub clientele, and cinema queues for ritualistic and symbolic forms. Mass-Observation quickly recruited a large group of voluntary observers (about a thousand) who would be “the meteorological stations from whose reports a weather-map of popular feeling can be compiled” (Mass-Observation, Mass-Observation 30). Mass-Observation combined the social survey with a relentless interest in the irrational and in what the world felt like to those who lived in it. As a consequence the file reports often seem banal and bizarre in equal measure (accounts of nightmares, housework routines, betting activities). When Mass-Observation restarted in the 1980s the surrealistic impetus became less pronounced, but it was still there, implicit in the methodology. Today, both as an on-going project and as an archive of previous observational reports, Mass-Observation lives in archival boxes. You can find a list of what topics are addressed in each box; you can also find lists of the contributors, the voluntary Mass-Observers whose observations are recorded in the boxes. What better way to give you a flavour of these boxes than to offer you a sample of their listing activities. Here are observers, observing in 1983 the objects that reside on their mantelpieces. Here’s one:champagne cork, rubber band, drawing pin, two hearing aid batteries, appointment card for chiropodist, piece of dog biscuit.Does this conjure up a world? Do we have a set of clues, of material evidence, a small cosmology of relics, a reduced Wunderkammer, out of which we can construct not the exotic but something else, something more ordinary? Do you smell camphor and imagine antimacassars? Do you hear conversations with lots of mishearing? Are the hearing aid batteries shared? Is this a single person living with a dog, or do we imagine an assembly of chiropodist-goers, dog-owners, hearing aid-users, rubber band-pingers, champagne-drinkers?But don’t get caught imagining a life out of these fragments. Don’t get stuck on this list: there are hundreds to get through. After all, what sort of an archive would it be if it included a single list? We need more lists.Here’s another mantelpiece: three penknives, a tube of cement [which I assume is the sort of rubber cement that you get in bicycle puncture repair kits], a pocket microscope, a clinical thermometer.Who is this? A hypochondriacal explorer? Or a grown-up boy-scout, botanising on the asphalt? Why so many penknives? But on, on... And another:1 letter awaiting postage stamp1 diet book1 pair of spare spectacles1 recipe for daughter’s home economics1 notepad1 pen1 bottle of indigestion tablets1 envelope containing 13 pence which is owed a friend1 pair of stick-on heels for home shoe repairing session3 letters in day’s post1 envelope containing money for week’s milk bill1 recipe cut from magazine2 out of date letters from schoolWhat is the connection between the daughter’s home economics recipe and the indigestion tablets? Is the homework gastronomy not quite going to plan? Or is the diet book causing side-effects? And what sort of financial stickler remembers that they owe 13p; even in 1983 this was hardly much money? Or is it the friend who is the stickler? Perhaps this is just prying...?But you need more. Here’s yet another:an ashtray, a pipe, pipe tamper and tobacco pouch, one decorated stone and one plain stone, a painted clay model of an alien, an enamelled metal egg from Hong Kong, a copper bracelet, a polished shell, a snowstorm of Father Christmas in his sleigh...Ah, a pipe smoker, this much is clear. But apart from this the display sounds ritualistic – one stone decorated the other not. What sort of religion is this? What sort of magic? An alien and Santa. An egg, a shell, a bracelet. A riddle.And another:Two 12 gauge shotgun cartridges live 0 spread Rubber plantBrass carriage clockInternational press clock1950s cigarette dispenser Model of Panzer MKIV tankWWI shell fuseWWI shell case ash tray containing an acorn, twelve .22 rounds of ammunition, a .455 Eley round and a drawing pinPhoto of Eric Liddell (Chariots of Fire)Souvenir of Algerian ash tray containing marbles and beach stonesThree 1930s plastic duck clothes brushesLetter holder containing postcards and invitations. Holder in shape of a cow1970s Whizzwheels toy carWooden box of jeweller’s rottenstone (Victorian)Incense holderWorld war one German fuse (used)Jim Beam bottle with candle thereinSol beer bottle with candle therein I’m getting worried now. Who are these people who write for Mass-Observation? Why so much military paraphernalia? Why such detail as to the calibrations? Should I concern myself that small militias are holding out behind the net curtains and aspidistra plants of suburban England?And another:1930s AA BadgeAvocado PlantWooden cat from MexicoKahlua bottle with candle there in1950s matchbook with “merry widow” cocktail printed thereonTwo Britain’s model cannonOne brass “Carronade” from the Carron Iron Works factory shopPhotography pass from Parkhead 12/11/88Grouse foot kilt pinBrass incense holderPheasant featherNovitake cupBlack ash tray with beach pebbles there inFull packet of Mary Long cigarettes from HollandPewter cocktail shaker made in ShanghaiI’m feeling distance. Who says “there in” and “there on?” What is a Novitake cup? Perhaps I wrote it down incorrectly? An avocado plant stirs memories of trying to grow one from an avocado stone skewered in a cup with one “point” dunked in a bit of water. Did it ever grow, or just rot? I’m getting distracted now, drifting off, feeling sleepy...Some more then – let’s feed the listlessness of the list:Wood sculpture (Tenerife)A Rubber bandBirdJunior aspirinToy dinosaur Small photo of daughterSmall paint brushAh yes the banal bizarreness of ordinary life: dinosaurs and aspirins, paint brushes and rubber bands.But then a list comes along and pierces you:Six inch piece of grey eyeliner1 pair of nail clippers1 large box of matches1 Rubber band2 large hair gripsHalf a piece of cough candy1 screwed up tissue1 small bottle with tranquillizers in1 dead (but still in good condition) butterfly (which I intended to draw but placed it now to rest in the garden) it was already dead when I found it.The dead butterfly, the tranquillizers, the insistence that the mantelpiece user didn’t actually kill the butterfly, the half piece of cough candy, the screwed up tissue. In amongst the rubber bands and matches, signs of something desperate. Or maybe not: a holding on (the truly desperate haven’t found their way to the giant tranquillizer cupboard), a keeping a lid on it, a desire (to draw, to place a dead butterfly at rest in the garden)...And here is the methodology emerging: the lists works on the reader, listing them, and making them listless. After a while the lists (and there are hundreds of these lists of mantle-shelf items) begin to merge. One giant mantle shelf filled with small stacks of foreign coins, rubber bands and dead insects. They invite you to be both magical ethnographer and deadpan sociologist at one and the same time (for example, see Hurdley). The “Martian” ethnographer imagines the mantelpiece as a shrine where this culture worships the lone rubber band and itinerant button. Clearly a place of reliquary—on this planet the residents set up altars where they place their sacred objects: clocks and clippers; ammunition and amulets; coins and pills; candles and cosmetics. Or else something more sober, more sombre: late twentieth century petite-bourgeois taste required the mantelpiece to hold the signs of aspirant propriety in the form of emblems of tradition (forget the coins and the dead insects and weaponry: focus on the carriage clocks). And yet, either way, it is the final shelf that gets me every time. But it only got me, I think, because the archive had worked its magic: ransacked my will, my need to please, my desire. It had, for a while at least, made me listless, and listless enough to be touched by something that was really a minor catalogue of remainders. This sense of listlessness is the way that the archive productively defeats the “desire for the archive.” It is hard to visit an archive without an expectation, without an “image repertoire,” already in mind. This could be thought of as the apperception-schema of archival searching: the desire to see patterns already imagined; the desire to find the evidence for the thought whose shape has already formed. Such apperception is hard to avoid (probably impossible), but the boredom of the archive, its ceaselessness, has a way of undoing it, of emptying it. It corresponds to two aesthetic positions and propositions. One is well-known: it is Barthes’s distinction between “studium” and “punctum.” For Barthes, studium refers to a sort of social interest that is always, to some degree, satisfied by a document (his concern, of course, is with photographs). The punctum, on the other hand, spills out from the photograph as a sort of metonymical excess, quite distinct from social interest (but for all that, not asocial). While Barthes is clearly offering a phenomenology of viewing photographs, he isn’t overly interested (here at any rate) with the sort of perceptional-state the viewer might need to be in to be pierced by the puntum of an image. My sense, though, is that boredom, listlessness, tiredness, a sort of aching indifference, a mood of inattentiveness, a sense of satiated interest (but not the sort of disinterest of Kantian aesthetics), could all be beneficial to a punctum-like experience. The second aesthetic position is not so well-known. The Austrian dye-technician, lawyer and art-educationalist Anton Ehrenzweig wrote, during the 1950s and 1960s, about a form of inattentive-attention, and a form of afocal-rendering (eye-repelling rather than eye-catching), that encouraged eye-wandering, scanning, and the “‘full’ emptiness of attention” (Ehrenzweig, The Hidden Order 39). His was an aesthetics attuned to the kind of art produced by Paul Klee, but it was also an aesthetic propensity useful for making wallpaper and for productively connecting to unconscious processes. Like Barthes, Ehrenzweig doesn’t pursue the sort of affective state of being that might enhance such inattentive-attention, but it is not hard to imagine that the sort of library-tiredness of the archive would be a fitting preparation for “full emptiness.” Ehrenzweig and Barthes can be useful for exploring this archival mood, this orientation and attunement, which is also a disorientation and mis-attunement. Trawling through lists encourages scanning: your sensibilities are prepared; your attention is being trained. After a while, though, the lists blur, concentration starts to loosen its grip. The lists are not innocent recipients here. Shrapnel shards pull at you. You start to notice the patterns but also the spaces in-between that don’t seem to fit sociological categorisations. The strangeness of the patterns hypnotises you and while the effect can generate a sense of sociological-anthropological homogeneity-with-difference, sometimes the singularity of an item leaps out catching you unawares. An archive is an orchestration of order and disorder: however contained and constrained it appears it is always spilling out beyond its organisational structures (amongst the many accounts of archives in terms of their orderings, see Sekula, and Stoler, Race and Along). Like “Probate Inventories,” the mantelpiece archive presents material objects that connect us (however indirectly) to embodied practices and living spaces (Evans). The Mass-Observation archive, especially in its mantelpiece collection, is an accretion of temporalities and spaces. More crucially, it is an accumulation of temporalities materialised in a mass of spaces. A thousand mantelpieces in a thousand rooms scattered across the United Kingdom. Each shelf is syncopated to the rhythms of diverse durations, while being synchronised to the perpetual now of the shelf: a carriage clock, for instance, inherited from a deceased parent, its brass detailing relating to a different age, its mechanism perpetually telling you that the time of this space is now. The archive carries you away to a thousand living rooms filled with the momentary (dead insects) and the eternal (pebbles) and everything in-between. Its centrifugal force propels you out to a vast accrual of things: ashtrays, rubber bands, military paraphernalia, toy dinosaurs; a thousand living museums of the incidental and the memorial. This vertiginous archive threatens to undo you; each shelf a montage of times held materially together in space. It is too much. It pushes me towards the mantelshelves I know, the ones I’ve had a hand in. Each one an archive in itself: my grandfather’s green glass paperweight holding a fragile silver foil flower in its eternal grasp; the potions and lotions that feed my hypochondria; used train tickets. Each item pushes outwards to other times, other spaces, other people, other things. It is hard to focus, hard to cling onto anything. Was it the dead butterfly, or the tranquillizers, or both, that finally nailed me? Or was it the half a cough-candy? I know what she means by leaving the remnants of this sweet. You remember the taste, you think you loved them as a child, they have such a distinctive candy twist and colour, but actually their taste is harsh, challenging, bitter. There is nothing as ephemeral and as “useless” as a sweet; and yet few things are similarly evocative of times past, of times lost. Yes, I think I’d leave half a cough-candy on a shelf, gathering dust.[All these lists of mantelpiece items are taken from the Mass-Observation archive at the University of Sussex. Mass-Observation is a registered charity. For more information about Mass-Observation go to http://www.massobs.org.uk/]ReferencesBarthes, Roland. Camera Lucida. Translated by Richard Howard. London: Fontana, 1984.Calder, Angus, and Dorothy Sheridan, eds. Speak for Yourself: A Mass-Observation Anthology 1937–1949. Oxford: Oxford UP, 1985.Ehrenzweig, Anton. The Psychoanalysis of Artistic Vision and Hearing: An Introduction to a Theory of Unconscious Perception. Third edition. London: Sheldon Press, 1965. [Originally published in 1953.]---. The Hidden Order of Art. London: Paladin, 1970.Evans, Adrian. “Enlivening the Archive: Glimpsing Embodied Consumption Practices in Probate Inventories of Household Possessions.” Historical Geography 36 (2008): 40-72.Highmore, Ben. Everyday Life and Cultural Theory. London: Routledge, 2002.---. Ordinary Lives: Studies in the Everyday. Abingdon: Routledge, 2011.Hubble, Nick. Mass-Observation and Everyday Life: Culture, History, Theory, Houndmills and New York: Palgrave, 2006.Hurdley, Rachel. “Dismantling Mantelpieces: Narrating Identities and Materializing Culture in the Home.” Sociology 40, 4 (2006): 717-733Mass-Observation. Mass-Observation. London: Fredrick Muller, 1937.---. First Year’s Work 1937-38. London: Lindsay Drummond, 1938.---. Britain. Harmondsworth: Penguin, 1939.Sekula, Allan. “The Body and the Archive.” October 39 (1986): 3-64.Sheridan, Dorothy, Brian Street, and David Bloome. Writing Ourselves: Mass-Observation and Literary Practices. Cresskill, New Jersey: Hampton Press, 2000.Stoler, Ann Laura. Race and the Education of Desire: Foucault’s History of Sexuality and the Colonial Order of Things. Durham and London: Duke UP, 1995. Stoler, Ann Laura. Along the Archival Grain: Epistemic Anxieties and Colonial Common Sense. Princeton: Princeton UP, 2009.

Depuis les travaux de schur et weyl, on sait que les representations irreductibles et polynomiales du groupe lineaire d'un espace vectoriel complexe de dimension finie v sont parametrees par les partitions, c'est a dire par les suites finies decroissantes d'entiers positifs. De plus, ces representations peuvent etre calculees en appliquant a v un foncteur (le foncteur de schur). Ce qui permet de definir le plethysme comme la composition de deux foncteurs de schur, par exemple la composition de deux puissances symetriques. Dans ce travail, nous etudions l'evolution des multiplicites de certaines composantes lorsqu'on fait croitre les parts de la partition qui definit le plethysme. Nous obtenons une propriete tres generale de croissance et de stabilite, dans le cas ou on applique un foncteur de schur a une representation irreductible d'un groupe algebrique reductif. Nous appliquons ensuite cette propriete au groupe lineaire de v. Ce qui nous permet d'obtenir des conditions necessaires pour qu'une representation irreductible apparaisse dans un plethysme. Ces conditions sont sous la forme d'inequations lineaires dans les parts des partitions definissant la representation irreductible et le foncteur de schur. Nous obtenons un resultat analogue pour la decomposition du produit tensoriel de deux representations quelconques du groupe symetrique

Quelques aspects de la géométrie des espaces LipschitzEn premier lieu, nous donnons les propriétés fondamentales des espaces Lipschitz libres. Puis, nous démontrons que l'image canonique d'un espace métrique M est faiblement fermée dans l'espace libre associé F(M). Nous prouvons un résultat similaire pour l'ensemble des molécules.Dans le second chapitre, nous étudions les conditions sous lesquelles F(M) est isométriquement un dual. En particulier, nous généralisons un résultat de Kalton sur ce sujet. Par la suite, nous nous focalisons sur les espaces métriques uniformément discrets et sur les espaces métriques provenant des p-Banach.Au chapitre suivant, nous explorons le comportement de type l1 des espaces libres. Entre autres, nous démontrons que F(M) a la propriété de Schur dès que l'espace des fonctions petit-Lipschitz est 1-normant pour F(M). Sous des hypothèses supplémentaires, nous parvenons à plonger F(M) dans une somme l_1 d'espaces de dimension finie.Dans le quatrième chapitre, nous nous intéressons à la structure extrémale de $F(M)$. Notamment, nous montrons que tout point extrémal préservé de la boule unité d'un espace libre est un point de dentabilité. Si F(M) admet un prédual, nous obtenons une description précise de sa structure extrémale.Le cinquième chapitre s'intéresse aux fonctions Lipschitziennes à valeurs vectorielles. Nous généralisons certains résultats obtenus dans les trois premiers chapitres. Nous obtenons également un résultat sur la densité des fonctions Lipschitziennes qui atteignent leur norme
Some aspects of the geometry of Lipschitz free spaces.First and foremost, we give the fundamental properties of Lipschitz free spaces. Then, we prove that the canonical image of a metric space M is weakly closed in the associated free space F(M). We prove a similar result for the set of molecules.In the second chapter, we study the circumstances in which F(M) is isometric to a dual space. In particular, we generalize a result due to Kalton on this topic. Subsequently, we focus on uniformly discrete metric spaces and on metric spaces originating from p-Banach spaces.In the next chapter, we focus on l1-like properties. Among other things, we prove that F(M) has the Schur property provided the space of little Lipschitz functions is 1-norming for F(M). Under additional assumptions, we manage to embed F(M) into an l1-sum of finite dimensional spaces.In the fourth chapter, we study the extremal structure of F(M). In particular, we show that any preserved extreme point in the unit ball of a free space is a denting point. Moreover, if F(M) admits a predual, we obtain a precise description of its extremal structure.The fifth chapter deals with vector-valued Lipschitz functions.We generalize some results obtained in the first three chapters.We finish with some considerations of norm attainment. For instance, we obtain a density result for vector-valued Lipschitz maps which attain their norm

Nous étudions plusieurs propriétés fonctionnelles d'inconditionnalité en les exprimant à l'aide de multiplicateurs. La première partie est consacrée à l'étude de phénomènes d'inconditionnalité isométrique et presqu'isométrique dans les espaces de Banach séparables. Parmi ceux-ci, la notion la plus générale est celle de ``propriété d'approximation inconditionnelle métrique''. Nous la caractérisons parmi les espaces de Banach de cotype fini par une propriété simple d'``inconditionnalité par blocs''. En nous ramenant à des multiplicateurs de Fourier, nous étudions cette propriété dans les sous-espaces des espaces de Banach de fonctions sur le cercle qui sont engendrés par une suite de caractères $e^(int)$. Nous étudions aussi les suites basiques inconditionnelles isométriques et presqu'isométriques de caractères, en particulier les ensembles de Sidon de constante asymptotiquement 1. Nous obtenons dans chaque cas des propriétés combinatoires sur la suite. La propriété suivante des normes $L^p$ est cruciale pour notre étude: si $p$ est un entier pair, $\int |f|^p = \int (|f^(p/2)|)^2 = \sum |\widehat(f^(p/2))(n)|^2$ est une expression polynomiale en les coefficients de Fourier de $f$ et $\bar f$. Nous proposons d'ailleurs une estimation précise de la constante de Sidon des ensembles à la Hadamard. La deuxième partie étudie les multiplicateurs de Schur: nous caractérisons les suites basiques inconditionnelles isométriques d'entrées de matrice $e_(ij)$ dans la classe de Schatten $S^p$. Les propriétés combinatoires que nous obtenons portent sur les chemins dans le réseau $\N \times \N$ à sommets dans cet ensemble. La troisième partie étudie le rapport entre la croissance d'une suite d'entiers et les propriétés harmoniques et fonctionnelles de la suite de caractères associée. Nous montrons en particulier que toute suite polynomiale, ainsi que la suite des nombres premiers, contient un ensemble $\Lambda(p)$ pour tout $p$ qui n'est pas de Rosenthal.

La liberté de conception des composites peut être améliorée par la combinaison de préimprégnés continus et discontinus. Le formage d’un empilement préchauffé constitué de plis discontinus distribués et orientés de manière optimale peut mener à des défauts inacceptables tels que des plissements dans le plan et hors-plan, glissement de plis, rotation de plis adjacents, flexion de fibres induite par un écoulement de compression transverse et finalement une distribution des fibres inappropriée et inefficace. Ces phénomènes naissent de la liberté individuelle de déplacement et de déformation des plis discontinus à l’intérieur du moule pendant la phase de formage. Premièrement ce travail présente des expériences conduites afin d’identifier le comportement sous compression d’un empilement de préimprégnés visqueux discontinus unidirectionnels et tissés. Un modèle basé sur une approche fluide hétérogène visqueux isotrope transverse est ensuite développé en accord avec les observations expérimentales. Il est notamment montré que les différents phénomènes observés sont retrouvés numériquement pour les unidirectionnels et partiellement pour les tissés et que les valeurs prédites sont globalement en bon accord avec les mesures expérimentales. L’obtention de résultats réalistes nécessite une résolution en 3D avec un maillage relativement fin dans l’épaisseur. Finalement des méthodes numériques avancées sont mises en place afin de tenter de réduire le coût des simulations
The design freedom of composites can be improved by combining continuous and discontinuous prepregs. The forming of a pre-heated blank made of optimally oriented and distributed discontinuous prepreg plies may lead to unacceptable defects such as in-plane and out-of-plane wrinkles, sliding of plies, rotation of adjacent plies, bending of fibres induced by transverse squeeze flow and finally to inappropriate and inefficient fibre distribution. This arises because the individual discontinuous plies are free to move and deform in the mould during the forming step. First, this work presents some experiments conducted to identify the behaviour of a stack of unidirectional and woven discontinuous viscous prepregs subjected to through-thickness compression. Then a model based on a heterogeneous transverse isotropic fluid approach is gradually developped in agreement with the experimental findings. It is shown that the various observed phenomena are retrieved for the unidirectional and partly for the woven prepreg by the numerical model. The predicted values are in good agreement with measurements, when the problem is solved in 3D with a relatively fine mesh in the thickness. Finally an attempt is made to reduce the computational cost by the use of advanced numerical simulation techniques