La restauration statistique non-supervisée de signaux admet d'innombrables applications dans les domaines les plus divers comme économie, santé, traitement du signal, ... Un des problèmes de base, qui est au coeur de cette thèse, est d'estimer une séquence cachée (Xn)1:N à partir d'une séquence observée (Yn)1:N. Ces séquences sont considérées comme réalisations, respectivement, des processus (Xn)1:N et (Yn)1:N. Plusieurs techniques ont été développées pour résoudre ce problème. Le modèle parmi le plus répandu pour le traiter est le modèle dit "modèle de Markov caché" (MMC). Plusieurs extensions de ces modèles ont été proposées depuis 2000. Dans les modèles de Markov couples (MMCouples), le couple (X, Y) est markovien, ce qui implique que p(x|y) est également markovienne (alors que p(x) ne l'est plus nécessairement), ce qui permet les mêmes traitements que dans les MMC. Plus récemment (2002) les MMCouples ont été étendus aux "modèles de Markov triplet" (MMT), dans lesquels on introduit un processus auxiliaire U et suppose que le triplet T = (X, U, Y) est markovien. Là encore il est possible, dans un cadre plus général que celui des MMCouples, d'effectuer des traitements avec une complexité raisonnable. L'objectif de cette thèse est de proposer des nouvelles modélisations faisant partie des MMT et d'étudier leur pertinence et leur intérêt. Nous proposons deux types de nouveautés: (i) Lorsque la chaîne cachée est discrète et lorsque le couple (X, Y) n'est pas stationnaire, avec un nombre fini de "sauts" aléatoires dans les paramètres, l'utilisation récente des MMT dans lesquels les sauts sont modélisés par un processus discret U a donné des résultats très convaincants (Lanchantin, 2006). Notre première idée est d'utiliser cette démarche avec un processus U continu, qui modéliserait des non-stationnarités "continues" de(X, Y). Nous proposons des chaînes et des champs triplets et présentons quelques expériences. Les résultats obtenus dans la modélisation de la non-stationnarité continue semblent moins intéressants que dans le cas discret. Cependant, les nouveaux modèles peuvent présenter d'autres intérêts; en particulier, ils semblent plus efficaces que les modèles "chaînes de Markov cachées" classiques lorsque le bruit est corrélé; (ii) Soit un MMT T = (X, U, Y) tel que X et Y sont continu et U est discret fini. Nous sommes en présence du problème de filtrage, ou du lissage, avec des sauts aléatoires. Dans les modélisations classiques le couple caché (X, U) est markovien mais le couple (U, Y) ne l'est pas, ce qui est à l'origine de l'impossibilité des calculs exacts avec une complexité linéaire en temps. Il est alors nécessaire de faire appel à diverses méthodes approximatives, dont celles utilisant le filtrage particulaire sont parmi les plus utilisées. Dans des modèles MMT récents le couple caché (X, U) n'est pas nécessairement markovien, mais le couple (U, Y) l'est, ce qui permet des traitements exacts avec une complexité raisonnable (Pieczynski 2009). Notre deuxième idée est d'étendre ces derniers modèles aux triplets T = (X, U, Y) dans lesquels les couples (U, Y) sont "partiellement" de Markov. Un tel couple (U, Y) n'est pas de Markov mais U est de Markov conditionnellement àY. Nous obtenons un modèle T = (X, U, Y) plus général, qui n'est plus de Markov, dans lequel le filtrage et le lissage exacts sont possibles avec une complexité linéaire en temps. Quelques premières simulations montrent l'intérêt des nouvelles modélisations en lissage en présence des sauts. / Statistical unsupervised restoration of signal can be applied in many fields such as economy, health, signal processing, meteorology, finance, biology, reliability, transportation, environment, ... the main problem treated in this thesis is to estimate a hidden sequence (Xn)1:N based on an observed sequence (Yn)1:N. In Probabilistic treatment of the problem in these sequences are considered as accomplishments of respectively, process (Xn)1:N and (Yn)1:N. Several techniques based on statistical methods have been developed to solve this problem. The most common model known for this kind of problems is the “hidden Markov model”. In this model we assume that the hidden process X is Markovian and laws p(y|x) of Y are conditional on X are sufficiently simple so that the law p(x|y) is also Markovian, this property is necessary for treatment. Many Extensions of these models have been proposed since 2000. In Markov models couples (MMCouples), more general than the MMC, the pair (X,Y) is Markovian), implying that p(x|y) is also Markovian (when p(x) is not necessarily markovian), which allows the same treatment as in MMC. More recently (2002), were extended to MMCouples are extended to Markov models Triplet (MMT), in which we introduce an auxiliary process U and suppose that the triple T=(X,U,Y) is Markovian. It’s again possible, in a general case of MMCouples, to perform treatments with a reasonable complexity. The objective of this thesis is to propose new modeling of MMT and to investigate their relevance and interest. We offer two types of innovations: (i) When the hidden system is discrete and when the couple (X,Y) is not stationary with a finite number of random “jumps” in parameters, the recent use of MMT where the jumps are modelized by a discrete process U has been very convincing (Lanchantin, 2006). Our first idea is to use this approach with a continuous process U, which models non-steady "continuous" of (X,Y). We propose chains and triplet fields and present some experiments. The results obtained in the modeling of non-stationarity still seem less interesting that in the discrete case. However, new models may have other interests, in particular, they seem more efficient than “classic hidden Markov” when the noise is correlated; (ii) Considering an MMT T=(X,U,Y) such that X and Y are continuous and U is discrete finite. We are dealing with a problem of filtering, or smoothing, with random jumps. In classic modelling the hidden pair (X,U) is Markovian, but the pair (U,Y) is not, what is the cause of the impossibility of Exact calculations with time linear complexity. It is then necessary to use various approximate methods, including methods using particle filtering which are the most common. In recent models MMT the hidden pair (X,U) is not necessarily Markovian, but the pair (U,Y) is Markovian, which allows accurate treatment with a reasonable complexity (Pieczynski 2009). Our second idea is to extend these models to triplets T=(X,U,Y) where the pairs (U,Y) are "partially" Markovian. Such a pair (U,Y) is not Markovian but U is conditionally Markovian on Y. We have in result a model with general model T=(X,U,Y) , which is no more Markovian, wherein the filtering and smoothing are accurate possible with time linear complexity. Some preliminary Simulations show the importance of new smoothing models with of jumps.

Background: The relevance of the food system for economic, environmental and social well-being is vital to consider. However, there is a lack of research covering issues and performance assessments of the supply chains in the food industry. Due to pressures on the natural environment and unsustainable production and distribution, Short Food Supply Chains (SFSC’s) have arisen as an alternative model to conventional supply chains. However, there is a need for more research in the field as its showing to be a growing trend in the food industry. Purpose: The purpose of this research is to study the topic of SFSC, where the focus in this paper is to explore what advantages and barriers food producers experience when operating within a SFSC. Method: This study is exploratory and follows an inductive and qualitative approach, where 6 semi-structured interviews with local food producers were used to collect data. The data was analysed and connected to previous literature using a thematic analysis.   Conclusion: The findings in this research illuminates that the advantages and barriers from selling through SFSC´s depends on the circumstances of the channel and the characteristics of the producers. They experienced advantages in their organization such as a high professional satisfaction, fair compensation and autonomy. The social proximity between the actors also facilitated the management of information and allowed for supply chain flexibility. However, producers also faced barriers such as the lack of proper governance in the SFSC channels, and logistical challenges such as the uncertainty of production and the difficulty of ensuring the efficiency of transportations. The analysis of SFSC’s is still in its early stages and the necessary innovations to attain the full positive effects have yet to be implemented.

We hypothesized that the presence of monoclonal free light chains (FLC) in the serum of patients with monoclonal gammopathy of undetermined significance (MGUS) is a marker of clonal evolution and a risk factor for progression. Forty-seven patients with MGUS and documented progression to myeloma or related malignancy were compared with 50 age- and gender-matched patients with MGUS and no evidence of progression after 5 or more years of follow-up. The presence of an abnormal kappa/lambda FLC ratio in the serum was associated with a higher risk of MGUS progression (relative risk 2.5; 95% confidence interval: 1.6-4.0; P < 0.001).

Les modélisations par chaînes de Markov cachées permettent de résoudre un grand nombre de problèmes inverses se posant en traitement d’images ou de signaux. En particulier, le problème de segmentation figure parmi les problèmes où ces modèles ont été le plus sollicités. Selon ces modèles, la donnée observable est considérée comme une version bruitée de la segmentation recherchée qui peut être modélisée à travers une chaîne de Markov à états finis. Des techniques bayésiennes permettent ensuite d’estimer cette segmentation même dans le contexte non-supervisé grâce à des algorithmes qui permettent d’estimer les paramètres du modèle à partir de l’observation seule. Les chaînes de Markov cachées ont été ultérieurement généralisées aux chaînes de Markov couples et triplets, lesquelles offrent plus de possibilités de modélisation tout en présentant des complexités de calcul comparables, permettant ainsi de relever certains défis que les modélisations classiques ne supportent pas. Un lien intéressant a également été établi entre les modèles de Markov triplets et la théorie de l’évidence de Dempster-Shafer, ce qui confère à ces modèles la possibilité de mieux modéliser les données multi-senseurs. Ainsi, dans cette thèse, nous abordons trois difficultés qui posent problèmes aux modèles classiques : la non-stationnarité du processus caché et/ou du bruit, la corrélation du bruit et la multitude de sources de données. Dans ce cadre, nous proposons des modélisations originales fondées sur la très riche théorie des chaînes de Markov triplets. Dans un premier temps, nous introduisons les chaînes de Markov à bruit M-stationnaires qui tiennent compte de l’aspect hétérogène des distributions de bruit s’inspirant des chaînes de Markov cachées M-stationnaires. Les chaînes de Markov cachée ML-stationnaires, quant à elles, considèrent à la fois la loi a priori et les densités de bruit non-stationnaires. Dans un second temps, nous définissons deux types de chaînes de Markov couples non-stationnaires. Dans le cadre bayésien, nous introduisons les chaînes de Markov couples M-stationnaires puis les chaînes de Markov couples MM-stationnaires qui considèrent la donnée stationnaire par morceau. Dans le cadre évidentiel, nous définissons les chaînes de Markov couples évidentielles modélisant l’hétérogénéité du processus caché par une fonction de masse. Enfin, nous présentons les chaînes de Markov multi-senseurs non-stationnaires où la fusion de Dempster-Shafer est employée à la fois pour modéliser la non-stationnarité des données (à l’instar des chaînes de Markov évidentielles cachées) et pour fusionner les informations provenant des différents senseurs (comme dans les champs de Markov multi-senseurs). Pour chacune des modélisations proposées, nous décrivons les techniques de segmentation et d’estimation des paramètres associées. L’intérêt de chacune des modélisations par rapport aux modélisations classiques est ensuite démontré à travers des expériences menées sur des données synthétiques et réelles / Hidden Markov chains (HMCs) based approaches have been shown to be efficient to resolve a wide range of inverse problems occurring in image and signal processing. In particular, unsupervised segmentation of data is one of these problems where HMCs have been extensively applied. According to such models, the observed data are considered as a noised version of the requested segmentation that can be modeled through a finite Markov chain. Then, Bayesian techniques such as MPM can be applied to estimate this segmentation even in unsupervised way thanks to some algorithms that make it possible to estimate the model parameters from the only observed data. HMCs have then been generalized to pairwise Markov chains (PMCs) and triplet Markov chains (TMCs), which offer more modeling possibilities while showing comparable computational complexities, and thus, allow to consider some challenging situations that the conventional HMCs cannot support. An interesting link has also been established between the Dempster-Shafer theory of evidence and TMCs, which give to these latter the ability to handle multisensor data. Hence, in this thesis, we deal with three challenging difficulties that conventional HMCs cannot handle: nonstationarity of the a priori and/or noise distributions, noise correlation, multisensor information fusion. For this purpose, we propose some original models in accordance with the rich theory of TMCs. First, we introduce the M-stationary noise- HMC (also called jumping noise- HMC) that takes into account the nonstationary aspect of the noise distributions in an analogous manner with the switching-HMCs. Afterward, ML-stationary HMC consider nonstationarity of both the a priori and/or noise distributions. Second, we tackle the problem of non-stationary PMCs in two ways. In the Bayesian context, we define the M-stationary PMC and the MM-stationary PMC (also called switching PMCs) that partition the data into M stationary segments. In the evidential context, we propose the evidential PMC in which the realization of the hidden process is modeled through a mass function. Finally, we introduce the multisensor nonstationary HMCs in which the Dempster-Shafer fusion has been used on one hand, to model the data nonstationarity (as done in the hidden evidential Markov chains) and on the other hand, to fuse the information provided by the different sensors (as in the multisensor hidden Markov fields context). For each of the proposed models, we describe the associated segmentation and parameters estimation procedures. The interest of each model is also assessed, with respect to the former ones, through experiments conducted on synthetic and real data

Ce travail de thèse a eu pour thème principal le protéoglycane syndecan-1 au cours du myélome multiple, une hémopathie maligne caractérisée par la présence d'un clone de plasmocytes tumoraux au sein de la moelle osseuse. Syndecan-1 est un élément majeur de la physiopathologie du myélome multiple, ce protéoglycane étant au coeur d'un réseau complexe d'interactions moléculaires conditionnant le devenir des cellules plasmocytaires tumorales.Les chaînes de glycosaminoglycanes présentes sur le core protéique de syndecan-1sont responsables d'une grande partie de son activité. Nous avons ainsi caractérisé, par une approche transcriptomique, 100 gènes codant les protéines impliquées dans la synthèse et la modification de ces chaînes. Nous avons de cette manière identifié des cibles moléculairesen vue de moduler, voire d'inhiber leur activité.Dans le but d'identifier les métalloprotéinases des familles ADAM et ADAMTS susceptibles d'interagir avec syndecan-1, nous avons réalisé l'étude du profil d'expression des gènes codant ces reprolysines et leurs inhibiteurs dans les cellules de la différentiation lymphocytaire B, les cellules plasmocytaires normales et tumorales ainsi que dans l'environnement médullaire.Dans une dernière partie, nous avons évalué l'efficacité d'une approche d'inhibitiondes chaînes héparanes sulfates via l'utilisation de l'héparine. Nous observons que certaines lignées myélomateuses sont inhibées par l'héparine et ses dérivés et que ces mêmes lignées sont stimulées par l'antidote de l'héparine, le sulfate de protamine. Les mécanismes mis enjeu sont en relation avec la modulation de la biodisponibilité des facteurs permettant la croissance des cellules. / Multiple myeloma is a hematological malignancy characterized by the expansion of aclone of malignant plasma cells in the bone marrow compartment. Syndecan-1 is a majorproteoglycan involved in a complex network of molecular interactions in multiple myelomaphysiopathology. As heparan sulfate and chondroitin sulfate chains are the bioactive components ofsyndecan-1, we first analysed the signature of genes encoding 100 proteins involved in thesynthesis of these chains, from precursor uptake to post-translational modifications, usingAffymetrix microarrays.In order to identify the metalloproteinases belonging to ADAM and ADAMTS familiespotentially implicated in the interactions with syndecan-1, we performed a gene expressionprofile focused on the genes encoding these reprolysines and their inhibitors.In a last part, we evaluated the efficacy of an inhibitory approach based on theutilization of heparin in human myeloma cell lines in vitro, inhibitory effects being in relationwith a modulation of the biodisponibility of heparin-binding factors.This work led us to identify targets of interest in relation with syndecan-1 biology inmultiple myeloma. They could be used to design new therapeutic strategies.

Este trabalho busca avançar o conhecimento sobre Global Value Chains (GVC) e inovação com usuários ao estudar a influência da colaboração dos usuários finais no upgrading de desenvolvedores em cadeias digitais. A pesquisa sugere que esforços de inovação entre uma empresa fornecedora em cadeias digitais e seus usuários finais levam a tipos preferenciais de upgrading, que variam em função de características específicas da indústria de jogos e da governança da cadeia na qual o desenvolvedor está inserido. Os referenciais teóricos das Cadeias Globais de Valor (GVC), inovação com usuários finais e método de regressão logística são utilizados para estabelecer as estruturas analíticas para este trabalho. Os resultados do trabalho são: (i) validação do modelo MOA+ID (Motivação, Oportunidade, Habilidade, e Infraestrutura Digital) para estudar a colaboração entre fornecedores e usuário final; (ii) identificação que o impacto da interação com usuários finais no upgrading de desenvolvedores em cadeias jogos digitais depende de características específicas de tal indústria, e (iii) identificação que o impacto da interação com usuários no upgrading de desenvolvedores em cadeias jogos digitais depende da governança da cadeia na qual o desenvolvedor está inserido. Desenvolvedores de jogos pertencentes a cadeias cujas governança são dos tipos Mercado e Relacional apresentam upgrading devido a colaboração com usuário final por que possuem liberdade e competências para se beneficiarem da relação com usuários final. Desenvolvedores de jogos pertencentes a cadeias cujas governança são dos tipos Modular e Cativa não apresentam upgrading devido à interação com usuário devido ao baixo nível de dependência do governante da cadeia. / This work seeks to advance knowledge about Global Value Chains (GVC) and innovation with end-users through the study of the influence of collaboration with end-user on the upgrading of developers in digital chains. The research suggests that innovation efforts between a supplier in digital chains and end-users lead to preferential types of upgrading, which will vary depending on the specific characteristics of the digital gaming industry and the governance of the chain in which the developer is embedded. The theoretical frameworks of Global Value Chains (GVC), innovation with end-users and method of logistic regression are used to establish the analytical structures for this work. The results of the work are: (i) validation of the MOA + DI model (Motivation, Opportunity Ability, Digital Infrastructure) to study collaboration between suppliers and end-user; (ii) recognition that the impact of innovation with end-users on the upgrading of developers in digital game chains depends on specific characteristics of such industry, and (iii) recognition that the impact of innovation with end users on the upgrading of developers in digital game chains depends on the chain governance in which the developer is embedded. Game developers under the Market and Relational types of governance present upgrading due to collaboration with endusers because such developers have freedom and competencies to benefit from the end-user interface. Game developers under the Modular and Captive types of governance chains do not experienced upgrading due to the interface with end-user because such firms do not have opportunities and competencies to benefit from the end-user interface.

We present in this thesis a series of studies on the physical properties of some one dimensional systems. In particular we study the low energy properties of various spin chains and a junction of Luttinger wires. For spin chains we specifically look at the role of perturbations like frustrating interactions and dimerisation in a nearest neighbour chain and the formation of magnetisation plateaus in two kinds of models; one purely theoretical and the other motivated by experiments. In our second subject of interest we study using a renormalisation group analysis the effect of spin dependent scattering at a junction of Luttinger wires. We look at the physical effects caused by the interplay of electronic interactions in the wires and the scattering processes at the junction. The thesis begins with an introductory chapter which gives a brief glimpse of the ideas and techniques used in the specific problems that we have worked on. Our work on these problems is then described in detail in chapters 25. We now present a brief summary of each of those chapters. In the second chapter we look at the ground state phase diagram of the mixed-spin sawtooth chain, i.e a system where the spins along the baseline are allowed to be different from the spins on the vertices. The spins S1 along the baseline interact with a coupling strength J1(> 0). The coupling of the spins on the vertex (S2) to the baseline spins has a strength J2. We study the phase diagram as a function of J2/J1 [1]. The model exhibits a rich variety of phases which we study using spinwave theory, exact diagonalisation and a semi-numerical perturbation theory leading to an effective Hamiltonian. The spinwave theory predicts a transition from a spiral state to a ferrimagnetic state at J2S2/2J1S1 = 1 as J2/J1 is increased. The spectrum has two branches one of which is gapless and dispersionless (at the linear order) in the spiral phase. This arises because of the infinite degeneracy of classical ground states in that phase. Numerically, we study the system using exact diagonalisation of up to 12 unit cells and S1 = 1 and S2 =1/2. We look at the variation of ground state energy, gap to the lowest excitations, and the relevant spin correlation functions in the model. This unearths a richer phase diagram than the spinwave calculation. Apart from revealing a possibility of the presence of more than one kind of spiral phases, numerical results tell us about a very interesting phase for small J2. The spin correlation function (for the spin1/2s) in this region have a property that the nextnearest-neighbour correlations are much larger than the nearest neighbour correlations. We call this phase the NNNAFM (nextnearest neighbour antiferromagnet) phase and provide an understanding of this phase by deriving an effective Hamiltonian between the spin1/2s. We also show the existence of macroscopic magnetisation jumps in the model when one looks at the system close to saturation fields. The third chapter is concerned with the formation of magnetisation plateaus in two different spin models. We show how in one model the plateaus arise because of the competition between two coupling constants, and in the other because of purely geometrical effects. In the first problem we propose [2] a class of spin Hamiltonians which include as special cases several known systems. The class of models is defined on a bipartite lattice in arbitrary dimensions and for any spin. The simplest manifestation of such models in one dimension corresponds to a ladder system with diagonal couplings (which are of the same strength as the leg couplings). The physical properties of the model are determined by the combined effects of the competition between the ”rung” coupling (J’ )and the ”leg/diagonal” coupling (J ) and the magnetic field. We show that our model can be solved exactly in a substantial region of the parameter space (J’ > 2J ) and we demonstrate the existence of magnetisation plateaus in the solvable regime. Also, by making reasonable assumptions about the spectrum in the region where we cannot solve the model exactly, we prove the existence of first order phase transitions on a plateau where the sublattice magnetisations change abruptly. We numerically investigate the ladder system mentioned above (for spin1) to confirm all our analytical predictions and present a phase diagram in the J’/J - B plane, quite a few of whose features we expect to be generically valid for all higher spins. In the second problem concerning plateaus (also discussed in chapter 3) we study the properties of a compound synthesised experimentally [3]. The essential feature of the structure of this compound which gives rise to its physical properties is the presence of two kinds of spin1/2 objects alternating with each other on a helix. One kind has an axis of anisotropy at an inclination to the helical axis (which essentially makes it an Ising spin) whereas the other is an isotropic spin1/2 object. These two spin1/2 objects interact with each other but not with their own kind. Experimentally, it was observed that in a magnetic field this material exhibits magnetisation plateaus one of which is at 1/3rd of the saturation magnetisation value. These plateaus appear when the field is along the direction of the helical axis but disappear when the field is perpendicular to that axis. The model being used for the material prior to our work could not explain the existence of these plateaus. In our work we propose a simple modification in the model Hamiltonian which is able to qualitatively explain the presence of the plateaus. We show that the existence of the plateaus can be explained using a periodic variation of the angles of inclination of the easy axes of the anisotropic spins. The experimental temperature and the fields are much lower than the magnetic coupling strength. Because of this quite a lot of the properties of the system can be studied analytically using transfer matrix methods for an effective theory involving only the anisotropic spins. Apart from the plateaus we study using this modified model other physical quantities like the specific heat, susceptibility and the entropy. We demonstrate the existence of finite entropy per spin at low temperatures for some values of the magnetic field. In chapter 4 we investigate the longstanding problem of locating the gapless points of a dimerised spin chain as the strength of dimerisation is varied. It is known that generalising Haldane’s field theoretic analysis to dimerised spin chains correctly predicts the number of the gapless points but not the exact locations (which have determined numerically for a few low values of spins). We investigate the problem of locating those points using a dimerised spin chain Hamiltonian with a ”twisted” boundary condition [4]. For a periodic chain, this ”twist” consists simply of a local rotation about the zaxis which renders the xx and yy terms on one bond negative. Such a boundary condition has been used earlier for numerical work whereby one can find the gapless points by studying the crossing points of ground states of finite chains (with the above twist) in different parity sectors (parity sectors are defined by the reflection symmetry about the twisted bond). We study the twisted Hamiltonian using two analytical methods. The modified boundary condition reduces the degeneracy of classical ground states of the chain and we get only two N´eel states as classical ground states. We use this property to identify the gapless points as points where the tunneling amplitude between these two ground states goes to zero. While one of our calculations just reproduces the results of previous field theoretic treatments, our second analytical treatment gives a direct expression for the gapless points as roots of a polynomial equation in the dimerisation parameter. This approach is found to be more accurate. We compare the two methods with the numerical method mentioned above and present results for various spin values. In the final chapter we present a study of the physics of a junction of Luttinger wires (quantum wires) with both scalar and spin scattering at the junction ([5],[6]). Earlier studies have investigated special cases of this system. The systems studied were two wire junctions with either a fully transmitting scattering matrix or one corresponding to disconnected wires. We extend the study to a junction of N wires with an arbitrary scattering matrix and a spin impurity at the junction. We study the RG flows of the Kondo coupling of the impurity spin to the electrons treating the electronic interactions and the Kondo coupling perturbatively. We analyse the various fixed points for the specific case of three wires. We find a general tendency to flow towards strong coupling when all the matrix elements of the Kondo coupling are positive at small length scales. We analyse one of the strong coupling fixed points, namely that of the maximally transmitting scattering matrix, using a 1/J perturbation theory and we find at large length scales a fixed point of disconnected wires with a vanishing Kondo coupling. In this way we obtain a picture of the RG at both short and long length scales. Also, we analyse all the fixed points using lattice models to gain an understanding of the RG flows in terms of specific couplings on the lattice. Finally, we use to bosonisation to study one particular case of scattering (the disconnected wires) in the presence of strong interactions and find that sufficiently strong interactions can stabilise a multichannel fixed point which is unstable in the weak interaction limit.

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Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

NOBRE, Kennedy Cabral. Para uma concepção ampliada de cadeia de gêneros. 2009. 96f. – Dissertação (Mestrado) – Universidade Federal do Ceará, Departamento de Letras Vernáculas, Programa de Pós-graduação em Linguística, Fortaleza (CE), 2009. / Submitted by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2014-08-21T16:50:33Z No. of bitstreams: 1 2009_dis_kcnobre.pdf: 3195360 bytes, checksum: e63c207a7515e23ed99fd0ac9f1db4ae (MD5) / Approved for entry into archive by Márcia Araújo(marcia_m_bezerra@yahoo.com.br) on 2014-08-21T17:08:10Z (GMT) No. of bitstreams: 1 2009_dis_kcnobre.pdf: 3195360 bytes, checksum: e63c207a7515e23ed99fd0ac9f1db4ae (MD5) / Made available in DSpace on 2014-08-21T17:08:10Z (GMT). No. of bitstreams: 1 2009_dis_kcnobre.pdf: 3195360 bytes, checksum: e63c207a7515e23ed99fd0ac9f1db4ae (MD5) Previous issue date: 2009 / This research presents a review of the concept of genre chains from their origins in Bakhtin (2000 [1953]) to the discussion of the criteria proposed by Fairclough (2001a [1992], 2003) and Swales (2004) for its characterization. For these authors, genre chains is a systematic grouping of genres that are a regular transformation necessary, predictable and, consequently, chronological one genre to another. From the empirical analysis of genre chains located in the academic-educational range, we suggest a distinction between simple and complex chains. In the first, all the genres that constitute it would be produced in a single institutional framework, the linear arrangement would reveal aspects of the functioning of the activities of individual institutions. At this point, the single chains associate the concept of discipline thought by Foucault (2008c [1975]), since the establishment of a single chain aims at the regular institutional practices. The complex chains, in turn, are offshoots of a single chain through a link with genres produced in areas outside institutions. In this case, through the analysis of school advertisements, we find that single chains of a particular institution are actually complexified by generic practices of others, motivated by the ongoing hegemonic struggle. Also, we realized that the complexity of a single chain is restricted to areas that institutions shall practice mutual relationship of intercontextuality (MEURER, 2004). Finally, we claim that a genre chain is actually a discursive part of a chain practices in which discursive and non-discursive elements enter into its constitution. / Esta pesquisa apresenta uma revisão do conceito de cadeia de gêneros desde sua genealogia em Bakhtin (2000 [1953]) até a discussão dos critérios caracterizadores propostos por Fairclough (2001a [1992]; 2003) e por Swales (2004). Para estes autores, uma cadeia de gêneros diz respeito a um agrupamento sistemático de gêneros em que há uma transformação regular, necessária, previsível e, conseqüentemente, cronológica de um gênero a outro. A partir da análise empírica de cadeias de gêneros situadas no domínio institucional universitário-escolar, sugerimos uma distinção entre cadeias simples e complexas. Nas primeiras, todos os gêneros que a constituem seriam produzidos em um único âmbito institucional, cuja disposição linear revelaria aspectos do funcionamento das atividades de determinada instituição. Neste ponto, associamos às cadeias simples a noção de disciplina pensada por Foucault (2008c [1975]), uma vez que o estabelecimento de uma cadeia simples tem por propósito regular as práticas institucionais. As cadeias complexas, por sua vez, são desdobramentos de uma cadeia simples por meio de uma ligação com gêneros produzidos em domínios institucionais alheios. Nesse caso, por meio da análise de anúncios escolares, percebemos que cadeias simples de uma determinada instituição na verdade são complexificadas pelas práticas genéricas de outra, motivadas pela contínua luta hegemônica. Além disso, percebemos que a complexificação de uma cadeia simples se restringe a domínios interinstitucionais que mantêm entre si uma relação de intercontextualidade (MEURER, 2004). Por fim, alegamos que uma cadeia de gêneros é, na verdade, a parte discursiva de uma cadeia de práticas em cuja constituição entram elementos discursivos e não discursivos.