Une tresse est une classe d'équivalence de mots de tresse. Diverses formes normales sur les tresses ont été décrites dans la littérature, c'est-à-dire, divers moyens de sélection, pour toute tresse, d'un mot de tresse distingué la représentant. Définie de façon naturelle sur les monoïdes de tresses de Birman-Ko-Lee (ou duaux), la forme normale tournante peut être étendue au groupe de tresses tout entier. Ici, nous donnons des contraintes de nature combinatoire satisfaites par cette nouvelle forme normale. Nous en obtenons ainsi une caractérisation et montrons que l'ensemble des formes normales tournantes des tresses duales constitue un langage régulier.<br /><br />Un résultat de P. Dehornoy (1992) affirme que toute tresse non triviale admet un représentant sigma-défini. Ce résultat est à la base de la construction de l'ordre des tresses. A l'aide de la forme normale tournante et de ses propriétés, nous montrons que toute tresse admet un représentant sigma-défini de longueur quasi-géodésique, ce qui résout une question ouverte depuis une quinzaine d'années. <br /><br />Un résultat de R. Laver montre que les monoïdes de Birman-Ko-Lee munis de l'ordre des tresses sont bien ordonnés mais laisse ouvert la détermination de leurs longueurs.<br />A l'aide de la forme normale tournante, nous obtenons une caractérisation de l'ordre des tresses sur le monoïde de Birman-ko-Lee à n brins à partir de sa restriction sur celui à (n-1) brins. Une conséquence de ce résultat est une nouvelle démonstration du résultat de R. Laver ainsi que la détermination de la longueur des monoïdes de tresses duaux munis de l'ordre des tresses.

The problems we study in this thesis arise in computer science, extremal set theory and quantum computing. The first common feature of these problems is that each can be reduced to characterizing the independent sets of maximum size in a suitable graph. A second common feature is that the size of these independent sets meets an eigenvalue bound due to Delsarte and Hoffman. Thirdly, the graphs that arise belong to association schemes that have already been studied in other contexts. Our first problem involves covering arrays on graphs, which arises in computer science. The goal is to find a smallest covering array on a given graph <i>G</i>. It is known that this is equivalent to determining whether <i>G</i> has a homomorphism into a <i>covering array graph</i>, <i>CAG(n,g)</i>. Thus our question: Are covering array graphs cores? A covering array graph has as vertex set the partitions of <i>{1,. . . ,n}</i> into <i>g</i> cells each of size at least <i>g</i>, with two vertices being adjacent if their meet has size <i>g²</i>. We determine that <i>CAG(9,3)</i> is a core. We also determine some partial results on the family of graphs <i>CAG(g²,g)</i>. The key to our method is characterizing the independent sets that meet the Delsarte-Hoffman bound---we call these sets <i>ratio-tight</i>. It turns out that <i>CAG(9,3)</i> sits inside an association scheme, which will be useful but apparently not essential. We then turn our attention to our next problem: the Erdos-Ko-Rado theorem and its <i>q</i>-analogue. We are motivated by a desire to find a unifying proof that will cover both versions. The EKR theorem gives the maximum number of pairwise disjoint <i>k</i>-sets of a fixed <i>v</i>-set, and characterizes the extremal cases. Its <i>q</i>-analogue does the same for <i>k</i>-dimensional subspaces of a fixed <i>v</i>-dimensional space over <i>GF(q)</i>. We find that the methods we developed for covering array graphs apply to the EKR theorem. Moreover, unlike most other proofs of EKR, our argument applies equally well to the <i>q</i>-analogue. We provide a proof of the characterization of the extremal cases for the <i>q</i>-analogue when <i>v=2k</i>; no such proof has appeared before. Again, the graphs we consider sit inside of well-known association schemes; this time the schemes play a more central role. Finally, we deal with the problem in quantum computing. There are tasks that can be performed using quantum entanglement yet apparently are beyond the reach of methods using classical physics only. One particular task can be solved classically if and only if the graph &Omega;(<i>n</i>) has chromatic number <i>n</i>. The graph &Omega;(<i>n</i>) has as vertex set the set of all <i>± 1</i> vectors of length <i>n</i>, with two vertices adjacent if they are orthogonal. We find that <i>n</i> is a trivial upper bound on the chromatic number, and that this bound holds with equality if and only if the Delsarte-Hoffman bound on independent sets does too. We are thus led to characterize the ratio-tight independent sets. We are then able to leverage our result using a recursive argument to show that <i>&chi;</i>(&Omega;(<i>n</i>)) > <i>n</i> for all <i>n</i> > 8. It is notable that the reduction to independent sets, the characterization of ratio-tight sets, and the recursive argument all follow from different proofs of the Delsarte-Hoffman bound. Furthermore, &Omega;(<i>n</i>) also sits inside a well-known association scheme, which again plays a central role in our approach.

Vitamin D is important for bone development with immunomodulatory effects. This study investigated whether feeding CD-1 and interleukin 10 (IL-10) knockout (KO) dams low (25 IU/kg diet) or high (5,000 IU/kg diet) vitamin D affected bone health of dams as well as their offspring. Offspring were weaned to 1 of the 2 diets and followed to young adulthood. Unlike CD-1 dams, IL-10 KO dams experienced greater femur strength with high vitamin D. CD-1 male offspring had reduced femur neck strength and female offspring had smaller, weaker femurs, and weaker lumbar vertebra 2 (LV2) with high maternal vitamin D. IL-10 KO male offspring had larger femurs and female offspring had stronger femurs when weaned to high vitamin D. Low vitamin D did not adversely impact bone health but the optimal level of dietary vitamin D seems to differ between healthy and inflammatory states.

Vitamin D is important for bone development with immunomodulatory effects. This study investigated whether feeding CD-1 and interleukin 10 (IL-10) knockout (KO) dams low (25 IU/kg diet) or high (5,000 IU/kg diet) vitamin D affected bone health of dams as well as their offspring. Offspring were weaned to 1 of the 2 diets and followed to young adulthood. Unlike CD-1 dams, IL-10 KO dams experienced greater femur strength with high vitamin D. CD-1 male offspring had reduced femur neck strength and female offspring had smaller, weaker femurs, and weaker lumbar vertebra 2 (LV2) with high maternal vitamin D. IL-10 KO male offspring had larger femurs and female offspring had stronger femurs when weaned to high vitamin D. Low vitamin D did not adversely impact bone health but the optimal level of dietary vitamin D seems to differ between healthy and inflammatory states.

Fragile X Syndrome (FXS) is the leading cause of inherited intellectual disability. The disorder is caused by a trinucleotide expansion that silences the Fragile X Mental Retardation 1 (Fmr1) gene resulting in the loss of its protein product, the Fragile X Mental Retardation Protein (FMRP). FXS patients show broad clinical phenotypes including intellectual disability, as well as a number of cognitive and behavioral problems. The lack of FMRP is believed to be the direct cause of the deficits seen in FXS patients. FMRP is an RNA-binding protein that is expressed in the brain and testes. This protein is believed to form a messenger ribonucleoprotein complex with mRNAs in the nucleus and subsequently export them to polyribosomes in the cytoplasm, therefore influencing translation of its bound mRNAs. Importantly, FMRP has long been suspected to be involved in synaptic plasticity due to its ability to bind several mRNAs that encode for proteins important in synaptic plasticity. Such proteins include the GluN1, GluN2A and GluN2B subunits of the N-methyl-D- aspartate receptor (NMDAR). FMRP is expressed in the hippocampus, a region of the brain involved in learning and memory processes. Recently, impaired NMDAR functioning in the dentate gyrus (DG) subregion of the hippocampus has been observed in Fmr1 knockout (-/y) mice. This impairment also resulted in reduction in long-term potentiation (LTP) and long-term depression (LTD) of synaptic efficacy, two biological models of learning and memory. In the present study, I focused on the levels of the NMDAR GluN1, GluN2B and Glu2B subunits in order to determine the synaptic plasticity alterations seen in the DG of Fmr1-/y mice. Using Western blotting, I found that there is a decrease in the GluN1, GluN2A and GluN2B subunits in the DG of young adult Fmr1-/y mice, indicating that these mice have significantly lower amounts of total NMDARs. These results could explain the altered LTP and LTD seen in Fmr1-/y mice at the molecular level and might contribute to the intellectual impairments seen in these KO mice. NMDARs appear to be important in the development and maturation of synapses. The GluN2A and GluN2B subunits are developmentally regulated, where GluN2B is predominantly expressed early in development and GluN2A in the adult brain. A dysregulation of GluN2A and GluN2B subunits has been proposed to affect the maturation and formation of synapses. Intriguingly, FMRP is also believed to play a functional role in early brain development. Thus, this study also focused on the developmental expression of the GluN1, GluN2A and GluN2B subunits in the DG, Cornu Ammonis, prefrontal cortex and cerebellum of Fmr1-/y mice, all of which are brain regions implicated in FXS. We found that the developmental expression of these subunits is altered in Fmr1-/y mice in specific brain regions. Together, these results demonstrate that the loss of FMRP differentially affects GluN1, GluN2A and GluN2B subunit expression both developmentally and spatially, further implicating NMDARs in the pathophysiology of FXS. / Graduate

La dégradation des fonctions de reproduction masculine dans les dernières décennies, et par suite, la baisse du taux de fertilité chez l'homme a renforcé les démarches de recherche des causes d'infertilité masculine, qu'elles soient génétiques, ou environnementales, mettant en œuvre les perturbateurs endocriniens ou d'autres produits reprotoxiques. Par ailleurs, les traitements palliatifs tels que l'aide médicale à la procréation ne permettent qu'à 1 couple sur deux d'obtenir une grossesse. La recherche vise donc également à définir de nouvelles pistes d'amélioration de ces techniques. Les phospholipases A2 (PLA2) sont des enzymes abondamment exprimées dans les organes reproducteurs mâles, le sperme éjaculé et dans le tractus génital femelle. Elles jouent des rôles importants dans la capacitation, la réaction acrosomique (RA) et la fécondation. Nous avons montré au laboratoire que la PLA2 murine secrétée de groupe X (mGX) est présente dans l'acrosome des spermatozoïdes de souris. Elle est libérée au cours de la RA et s'avère un inducteur puissant de la RA. Les mécanismes permettant ces effets sont encore mal connus. Par l'utilisation d'inducteurs et d'inhibiteurs des PLA2, sur des modèles murins wild type ou KO pour certaines PLA2, ce travail montre que durant la capacitation, l'activation des iPLA2 β permet de déclencher une RA spontanée dans une sous-population spécifique de spermatozoïdes. Au cours de la RA induite par la progestérone (P4), On a pu aussi valoriser le rôle des iPLA2 β qui initie la cascade de la RA et permet que les sPLA2 soient activées pour amplifier le déroulement de la réaction acrosomique. Par ailleurs, ce travail montre que l'effet de mGX sur le taux de fécondation et de développement embryonnaire ne dépend pas du taux de la RA. Cet effet obtenu grâce à mGX n'est pas observé avec d'autres sPLA2 (murine ou humaine), ni avec la P4 ce qui lui confère une propriété espèce dépendante. / For the last ten years, the impairment of the male reproductive functions has highly increased, while the use of assisted reproductive techniques has also increased. Despite this evolution, the pregnancy rates obtained in in vitro fertilization (IVF) remain low, as only one in two couples will obtain a pregnancy after 4 attempts. Research has to discover new ways to gain in reproductive impact. Hence, many studies have recently been developed to test molecules that could improve the IVF results. Phospholipases A2 (PLA2s) are part of these molecules. They play an important role, because of their abundant expression in: male reproductive organs, in ejaculated sperm and in the female tract. Several studies have suggested a role for members of the secreted phospholipase A2 family in capacitation, acrosome reaction (AR), and fertilization. We demonstrated previously that sperm from mGX knock-out mice had a severely impaired fertilization potential in vitro, but the molecular nature of these enzymes and their specific functions have remained elusive. Our aims were to study the mechanism of the acrosome reaction by focusing on different kinds of PLA2 using inhibitors and knockout mice for each type of PLA2. We demonstrate the importance of iPLA2β in spontaneous AR occurring during capacitation. We also show that iPLA2β and sPLA2 of group X are both involved in progesterone (P4)-induced AR in mouse sperm. In addition we show that in the mouse neither P4 nor any of the other sPLA2s tested are able to mimic the IVF improvement obtained with mGX-treatment. We also demonstrate that this improvement obtained with phospholipase A2 murine group X is not dependent on the rate of AR. These results demonstrate that sPLA2s are not commutable in the context of mouse sperm fertility, indicating that group X sPLA2 is unique to improve fertility outcome.

Ordspråk som “gråt inte över spilld mjölk” är ett tecken på hur mycket mjölken som livsmedel värdesätts i det svenska samhället. I den här kvalitativa studien kommer mjölkens roll i samhället sättas i relation till skolans verksamhet. Fokusgruppen är grundskollärare som undervisar i de naturvetenskapliga ämnena i årskurs F-9. Utifrån kritisk djurteori analyseras upprätthållandet av maktrelationen mellan människan och djuret genom att undersöka via internetbaserad enkät hur lärare förhåller sig till mjölk och mjölkproduktion i undervisningen för de naturvetenskapliga ämnena.Det sammanställda resultatet visar att människans uppfattning om “mjölk och mjölkproduktion” i undervisningen påverkas av deras syn på kunskap och etikens relevans i undervisningen. Skolan är en institution som påverkas av samhällets gemensamma värderingar. Det finns yttre påverkan såsom ekonomisk stöd från politiker och läromedel från industrier som gynnas av att framställa mjölkens fördelar, vilket skapar förutsättningar och strukturer till att acceptera ett rådande maktförhållande som finns mellan människan och djuret. Lärare som inte har kunskap om mjölkproduktionens alla delar eller kan förhålla sig till etiska perspektiv (som ser på djuret som en individ snarare än objekt) finner oftast inga möjligheter till att ifrågasätta det som framställs på reklam eller mjölkindustrins informationsblad. De djur som representeras på reklam för att marknadsföra mjölkprodukter är oftast en idealisk bild av produktionsprocessen vilket skapar en illusion av att det inte finns något att problematisera. Grundskollärare finner därmed att det inte finns tid eller relevant koppling till kursplanens centrala innehåll i läroplanen för att mjölken ska kunna beröras i undervisningen. Studien kommer däremot fram till förslag på hur lärare kan använda djuretik som ett förhållningssätt i klassrummet för att t.ex. lyfta olika perspektiv och träna på att argumentera för sina personliga ställningstaganden.Den här studien belyser endast en liten del av hur skolans verksamhet bidrar till upprätthållandet av ett maktförhållande mellan människan och djuret. Studien visar även att skolan har potential att bidra med ifrågasättandet av samhällsordningen som legitimerar djurets position i mjölkproduktionssystemet och kan väcka diskussioner ur ett miljö-, hälso- och etisk perspektiv. Däremot krävs det att man har kunskap om, intresse för och viljan att våga ifrågasätta normer som är djupt integrerade i den svenska kulturen. Det krävs fler studier som undersöker sambandet mellan skolans förhållningssätt till djur och hur djur representeras i naturvetenskapliga ämnenas undervisningsinnehåll.

Endkunden legen bei ihren Kaufentscheidungen immer mehr Wert auf Individualität. Als Reaktion darauf, haben Unternehmen das Potential der Co-Creation erkannt. Dies beschreibt die Zusammenstellung eines komplexen Produktes durch den Kunden selbst. Auch Campeleon nutzt Co-Creation im Rahmen der Produktentwicklung. Das Start Up entwickelt in enger Zusammenarbeit mit Pilotkunden modulare Ausstattungsmodule für Reisemobile. Durch die intensive Interaktion mit dem Kunden konnten Anforderungen an die Produkte identifiziert werden, die ansonsten unentdeckt geblieben wären. So sind erste modulare Ausstattungsmodule entstanden, die es ermöglichen, den knappen Platz im Innenraum von Reisemobilen durch Mehrfachnutzung der Flächen zu maximieren. Neben einer innovativen Küchenlösung ist so auch ein modulares Camper-Bad entstanden. Gleichzeitig muss sich Campeleon immer wieder die Frage stellen, in welchem Maße Co-Creation sinnvoll genutzt werden kann und wann sie für den Kunden überfordernd wirkt. Daraus ist eine Checkliste entstanden, die Kunden dabei behilflich sein soll, ihre Gedanken zum Reisemobil-Ausbau zu ordnen. Dieser Artikel beleuchtet zum einen Vorteile und Herausforderungen von Co-Creation. Zum anderen wird die Entstehung eines Prozesses zur Umsetzung anhand eines Anwendungsbeispiels veranschaulicht.

This work deals with current application of the developing field of post-warranty service of old turbines in the energy sector. There are described various types of repairs following the recommendations of commonly performed actions. Revision finding is focused on back-pressure steam turbine marked R12-9 / 2, which was scheduled for overhaul after 180 000 operating hours. Revision findings include a detailed description of the turbine and method of repair. It is also performed calculating the losses in the axial blade stage of cascade by AMDC-KO methodology on because of the choice type of blading and then comparing by technical justification for the choice of one of the variants for the customer.

Research on service compensation is rare. In this article we examine different compensation rules for integrated services (IS) which are produced jointly by a service provider and his client. Examples are consulting, advertising or management training. We distinguish three different compensation rules and compare them with joint profit maximization where both, service provider and client act as one organizational unit. The ompensation rules are (1) the input based compensation (IBC) characterized by a compensation that is based on work hours or work days, (2) the sales based compensation (SBC) with the compensation based on client’s sales and (3) the profit based compensation (PBC) with compensation based on client’s profits. We can show that under reasonable, realistic conditions the IBC (surprisingly) leads to better results for the service provider and for the client as compared to the PBC and the SBC.