• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 480
  • 106
  • 97
  • 74
  • 40
  • 14
  • 13
  • 13
  • 8
  • 8
  • 6
  • 6
  • 5
  • 4
  • 4
  • Tagged with
  • 1064
  • 291
  • 281
  • 258
  • 155
  • 142
  • 138
  • 130
  • 121
  • 120
  • 103
  • 98
  • 93
  • 83
  • 78
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
571

Synthesis of unnatural amino acids for genetic encoding by the pyrrolysyl-tRNA/RNA synthetase system

Knight, William A 01 January 2015 (has links)
The complexity of all biomolecules in existence today can be attributed to the variation of the amino acid repertoire. In nature, 20 canonical amino acids are translated to form these biomolecules, however, many of these amino acids have revealed posttranslational modifications (i.e. acetylation, methylation) after incorporation. Amino acids that exhibit PTM are known for their involvement in cellular processes such as DNA repair and DNA replication; these PTMs are commonly found on histones within the chromatin complex. Utilization of in vivo site-specific incorporation has recently reported functionality of post-translationally modified amino acids.1 xii Here we report the synthesis and in vivo site-specific incorporation of the histone PTM, 2-hydroxyisobutyrl lysine (Khib), with the pyrrolysyl tRNA/ RNA synthetase system. This translational machine can better serve to probe Khib for functional benefits. Additionally, this thesis focuses much of its attention on the development of unnatural amino acids (UAA) with optogenetic characteristics. These UAAs, if site-specifically incorporated, can be used to control enzymes and proteins through rapid light perturbation (365nm UV light). Furthermore, discussed is the synthesis of photo-caged threonine and photo-caged serine as potential substrates for the pyrrolysyl translational machinery.
572

Integrální reprezentace operátorových algeber / Integral representation of operator algebras

Penk, Tomáš January 2013 (has links)
By a representation of a C*-algebra A on a Hilbert space H we mean a morphism : A → L(H). After summing up neccessary knowledge from the theory of Banach and Hilbert spaces and C*-al- gebras we show that for every C*-algebra a representation exists. We describe its structure detiledly and we focus on examining cyclic representations. We find out that cyclic representations relate to the state space. Because every state can be expressed as an integral with respect to an appropriate measure on the states, in is possible to assign a measure on the state space to each cyclic represen- tation. Therefore, we investigate connexion of a representation with this measure as same as with the corresponding state. This leads us to the definition of an orthogonal measure. We find out that its properties relate with certain subalgebras of L(H). At the end we show that for a separable C*-algebra it is possible to express a representation fulfilling suitable assumptions in the form of a direct integral. 1
573

Síntese de análogos de âncora de GPI: uma contribuição para a descoberta de novos alvos moleculares de Trypanosoma cruzi / Synthesis of GPI anchor analogues to support the discovery of new molecular targets of Trypanosoma cruzi

Morotti, Ana Luisa Malaco 11 December 2018 (has links)
Âncoras de glicosilfosfatidilinositol (GPI) são estruturas essenciais para a ancoragem de glicoconjugados e proteínas na superfície celular de protozoários. Trypanosoma cruzi produz uma gama de estruturas únicas de GPI, as quais ancoram mucinas e trans-sialidases, que participam de processos envolvidos na interação entre parasita e hospedeiro. Afim de estudar a biossíntese de âncora de GPI de T. cruzi e possivelmente utilizá-la como um potencial alvo anti-T.cruzi, este trabalho visa sintetizar análogos de âncoras de GPI e analisar o potencial destas moléculas como substratos da via biossintética de GPIs. Neste contexto, um pseudo-dissacarídeo 31 foi sintetizado através de O-glicosilação entre os doadores derivados de azido-glicopiranosídeo (32 ou 33a-d) e o acceptor de mio-inositol (34), preparados a partir de cloridrato de glucosamina (35) e metil-?-D-glucopiranósido (36), respectivamente, usando proteção/desproteção ortogonais. Cinco diferentes dadores de glicosídicos (32 e 33a-d) foram preparados para investigar a influcia dos seus grupos protetores na estereoselectividade da reações de O-glicosilação na presença de diferentes solventes para estudar o favorecimento da configuração ?, presente em GPIs. Ademais, a síntese do aceptor de mio-inositol 34 foi realizada em 12 etapas pela estratégia do rearranjo Ferrier para formar um derivado de ciclitol, além de diversas proteções/desproteções, funcionalizado que permite a introdução regiosselectiva da unidade de azido glicose (32-33a-d) e uma porção de fosfolípido no seu C-1 e posições C-6, respectivamente. Assim, O-glicosilação entre doador 33c e o acceptor 34, foi realizada utilizando TMSOTf como promotor para originar o composto 31c com boa estereoseletividade para ?, com elevado rendimento (~70%). Após a dealilação de 31c, a porção fosfodiéster contendo uma cadeia C-8 (87), preparada pela abordagem do H-fosfonato, foi anexada ao pseudo-dissacarídeo para gerar, após desprotecção global, o composto alvo 30a. A mesma estratégia sintética foi aplicada ao preparo do composto 91 contendo uma cadeia lateral alquil-naftil (90) que está em últmas etapas de desproteção para gerar o composto final 30c. Atualmente, o composto 30a está sendo testado como substrato da biossíntese de âncoras de GPI em membranas microssomais de Euglena gracilis, uma alga unicelular não patogênica, que pode potencialmente ser utilizada como modelo para parasitas humanos filogeneticamente relacionados. Após a incubação do potencial substrato de GPI 30a com membranas microssomais de E. gracilis para geração de metabólitos, será realizada análise do extrato por LC-MS e, eventualmente, isolamento dos produtos formados para posterior caracterização. Os produtos que apresentarem atividade como substrato ou como inibidores da biossíntese de GPI em E. gracilis serão também ensaiados na membrana microsomal do T. cruzi. / Glycosylphosphatidylinositol (GPI) anchors are essential molecules to attach glycoconjugates and proteins in protozoan\'s cell surface. Trypanosoma cruzi produces a range of unique GPI structures that anchor mucins and trans-sialidases which participate in important processes involved in the interaction between parasite and host. As an effort to study T. cruzi GPI anchor biosynthesis and possibly use it as a potential target for an antichagasic drug, this work aims to synthesize GPI anchor analogs (labelled or not) and analyze the potential of these molecules as substrates in the GPI biosynthetic pathway. In this context, a pseudo-disaccharide 31 was synthesized by O-glycosylation reaction between azide glycosyl donors (32 or 33a-d) and myo-inositol acceptor (34), prepared from glucosamine (35) hydrochloride and methyl ?-D-glucopyranoside (36), respectively, using orthogonal protection/ deprotection. Five different glycosyl donors (32 and 33a-d) were prepared to investigate the influence of their protective groups on the stereoselectivity of the O-glycosylation reaction in the presence of different solvents to afford the required GPI ?-linkage. In addition, the synthesis of the myo-inositol acceptor 34 was achieved using several protection/deprotection steps, besides the Ferrier rearrangement, to form a functionalized cyclitol derivative that enables the regioselective introduction of the azide glycoside unit and phospholipid moiety on its C-1 and C-6 positions, respectively. Then, O-glycosylation of acceptor 34 with donor 33c was accomplished in diethyl ether, using TMSOTf as promoter to give exclusively ?-anomer 31c in high yield. After deallylation of 31c, the phosphodiester moiety bearing an octyl chain (87), prepared by the H-phosphonate approach, was appended to the pseudo-disaccharide to yield, after deprotection, target compounds 30a. The same synthetic strategy was applied to the preparation of 30c, even though in the protective form, compound 91 bearing an alkyl-naphthyl side chain (90). Currently, compound 30a is being tested as substrates of GPI anchor biosynthesis in Euglena gracilis cell membranes, a non-pathogenic unicellular algae, which may potentially be used as a model for phylogenetically related human parasites. After incubation of the potential GPI substrate 30a with E. gracilis microsomal membranes for generation of metabolites, the analysis by LC-MS and, eventually, isolation of the products will be performed for further characterization. Products that show any substrate or inhibitory activities will be also assayed in T. cruzi microsomal membrane.
574

Contribution à la fiabilisation de la modélisation numérique de l’usinage de pièces en titane / Contribution to more reliable numerical modeling of the machining of titanium workpieces

Yaich, Mariem 28 November 2017 (has links)
L’usinage des pièces en alliages de titane, notamment en Ti6Al4V qui a une faible usinabilité, a été toujours parmi les préoccupations majeures des entreprises du secteur de l’aéronautique. Toutefois, il est difficile, en se basant seulement à des essais expérimentaux, de bien comprendre les mécanismes participants à la formation du copeau. Il est alors nécessaire d’avoir recours à des modélisations numériques fiables permettant d’avoir accès à des grandeurs physiques instantanées et très localisées. Le travail présenté porte sur la fiabilisation de la modélisation de la coupe. Des simulations numériques 2D et 3D ont été mises en place. Le modèle de comportement de Johnson-Cook et le critère énergétique d’évolution d’endommagement ont été utilisés. L’étude préliminaire 2D de l’effet du maillage, notamment la taille, le type et la fonction d’interpolation des éléments finis, a souligné l’importance d’une discrétisation convenable du modèle qui tient compte du coût de calculs. De plus, il a été montré qu’un choix convenable du type de la formulation est crucial. L’effet des coefficients rhéologiques et d’endommagement (initiation et évolution) sur la formation du copeau (morphologie, champ de déformation et de température) a été déterminé. Des essais expérimentaux de la coupe orthogonale du Ti6Al4V à différentes conditions de coupe ont été effectués. La dépendance de la géométrie du copeau et des efforts à la vitesse de coupe et à l’avance a été étudiée. Les résultats expérimentaux ont été utilisés pour la validation des modèles numériques 3D qui permettent une étude fine de la formation du copeau. Cette approche a permis de reproduire fidèlement les phénomènes physiques se produisant au niveau du plan médian de la pièce tout en tenant compte de l’écoulement de la matière sur les bords. Les résultats prédits ont mis en évidence que, même dans le cas d’une coupe orthogonale, la formation du copeau est bien un phénomène 3D. Afin d’augmenter la fiabilité des modèles numériques 3D, une nouvelle loi thermo-viscoplastique a été proposée. Cette loi, identifiée et implémentée dans le logiciel Abaqus® à travers la routine VUMAT©, a été utilisée pour la simulation de l’usinage du Ti6Al4V. Elle a conduit à une amélioration notable des résultats numériques. / Machining of titanium alloys workpieces, especially in Ti6Al4V which has a low machinability, has always been among the major preoccupations of the companies in the aeronautics sector. However, it is difficult, basing only on experimental tests, to well understand the mechanisms involved during the chip formation. In fact, the use of reliable numerical models that allow the access to instantaneous and very localized physical quantities is required. The presented work consists on the increase of the cutting modeling reliability. 2D and 3D numerical simulations have been performed. The Johnson-Cook constitutive model and the damage evolution criterion have been used. The preliminary 2D study focused on the mesh effect, especially the size of the finite element, its type and its interpolation function, has highlighted the importance of a convenient discretization of the model that takes into account the machining computing cost. In addition, it has been shown that a suitable choice of the formulation type is crucial. The effect of the rheological and damage (initiation and evolution) coefficients on the chip formation (morphology, strain and temperature field) has been determined. Experimental orthogonal cutting tests of the Ti6Al4V at different cutting conditions have been performed. The dependency of the chip geometry and the efforts to the cutting speed and the feed rate has been studied. Experimental results have been used in the validation of the 3D numerical models, which allow a deep study of the chip formation process. This approach has allowed an accurately reproduction of the physical phenomena that occurs in the median plan of the workpiece as well as in its sides. The predicted results have highlighted that, even in the case of orthogonal cutting process, the chip formation is a 3D phenomenon. In order to increase the reliability of 3D numerical models, a new thermo-visco-plastic law has been proposed. This law, identified and implemented in the software Abqus® through the subroutine VUMAT©, has been used to model machining process of the Ti6Al4V. It has resulted in a notable improvement of numerical results.
575

Statistique d’extrêmes de variables aléatoires fortement corrélées / Extreme value statistics of strongly correlated random variables

Perret, Anthony 22 June 2015 (has links)
La statistique des valeurs extrêmes est une question majeure dans divers contextes scientifiques. Cependant, bien que la description de la statistique d'un extremum global soit certainement une caractéristique importante, celle-ci ne se concentre que sur une seule variable parmi un grand nombre de variables aléatoires. Une question naturelle qui se pose alors est la suivante: ces valeurs extrêmes sont-elles isolées, loin des autres variables ou bien au contraire existe-t-il un grand nombre d'autres variables proches de ces valeurs extrêmes ? Ces questions ont suscité l'étude de la densité d'état de ces événements quasi-extrêmes. Il existe pour cette quantité peu de résultats pour des variables fortement corrélées, qui est pourtant le cas rencontré dans de nombreux modèles fondamentaux. Deux pistes de modèles physiques de variables fortement corrélées pouvant être étudiés analytiquement se démarquent alors: les positions d’une marche aléatoire et les valeurs propres de matrice aléatoire. Cette thèse est ainsi consacrée à l’étude de statistique d’extrêmes pour ces deux modèles de variables fortement corrélées. Dans une première partie, j’étudie le cas où la collection de variables aléatoires est la position au cours du temps d’un mouvement brownien, qui peut être contraint à être périodique, positif... Ce mouvement brownien est vu comme la limite d’un marcheur aléatoire classique après un grand nombre de pas. Il est alors possible d’interprèter ce problème comme celui d’une particule quantique dans un potentiel ce qui permet d’utiliser des méthodes puissantes issues de la mécanique quantique comme l’utilisation de propagateurs et de l’intégrale de chemin. Ces outils permettent de calculer la densité moyenne à partir du maximum pour les différents mouvements browniens contraints et même la distribution complète de cette quantité pour certains cas. Il est également possible de généraliser cette démarche à l’étude de plusieurs marches aléatoires indépendantes ou avec interaction. Cette démarche permet également d’effectuer une étude temporelle, ainsi que de généraliser à l’étude d’autres fonctionnelle du maximum. Dans la seconde partie, j’étudie le cas où la collection de variables aléatoires est composée des valeurs propres d’une matrice aléatoire. Ce travail se concentre sur l’études des matrices des ensembles gaussiens (GOE, GUE et GSE) ainsi qu’à l’étude des matrices de Wishart. L’étude du voisinage de la valeur propre maximale pour ces deux modèles est faite en utilisant une méthode fondée sur les propriétés des polynômes orthogonaux. Dans le cas des matrices gaussiennes unitaires GUE, j’ai obtenu une formule analytique pour la distribution à partir du maximum ainsi qu’une nouvelle expression de la statistique du gap entre les deux plus grandes valeurs propres en termes d’une fonction transcendante de Painlevé. Ces résultats, et plus particulièrement leurs généralisations aux cas GOE, sont alors appliqués à un modèle de verre de spin sphérique en champs moyen. Dans le cas des matrices de Wishart, l’analyse des polynômes orthogonaux dans le régime de double échelle m’a permis de retrouver les différentes statistiques de la valeur propre minimale et également de prouver une conjecture sur la première correction de taille finie pour des grandes matrices de la distribution de la valeur propre minimale dans la limite dite de «hard edge». / Extreme value statistics plays a keyrole in various scientific contexts. Although the description of the statistics of a global extremum is certainly an important feature, it focuses on the fluctuations of a single variable among many others. A natural question that arises is then the following: is this extreme value lonely at the top or, on the contrary, are there many other variables close to it ? A natural and useful quantity to characterize the crowding is the density of states near extremes. For this quantity, there exist very few exact results for strongly correlated variables, which is however the case encountered in many situations. Two physical models of strongly correlated variables have attracted much attention because they can be studied analytically : the positions of a random walker and the eigenvalues of a random matrix. This thesis is devoted to the study of the statistics near the maximum of these two ensembles of strongly correlated variables. In the first part, I study the case where the collection of random variables is the position of a Brownian motion, which may be constrained to be periodic or positive. This Brownian motion is seen as the limit of a classical random walker after a large number of steps. It is then possible to interpret this problem as a quantum particle in a potential which allows us to use powerful methods from quantum mechanics as propagators and path integral. These tools are used to calculate the average density from the maximum for different constrained Brownian motions and the complete distribution of this observable in certain cases. It is also possible to generalize this approach to the study of several random walks, independent or with interaction, as well as to the study of other functional of the maximum. In the second part, I study the case of the eigenvalues of random matrices, belonging to both Gaussian and Wishart ensembles. The study near the maximal eigenvalues for both models is performed using a method based on semi-classical orthogonal polynomials. In the case of Gaussian unitary matrices, I have obtained an analytical formula for the density near the maximum as well as a new expression for the distribution of the gap between the two largest eigenvalues. These results, and in particular their generalizations to different Gaussian ensembles, are then applied to the relaxational dynamics of a mean-field spin glass model. Finally, for the case of Wishart matrices I proposed a new derivation of the distribution of the smallest eigenvalue using orthogonal polynomials. In addition, I proved a conjecture on the first finite size correction of this distribution in the «hard edge» limit.
576

Técnica urbana ortogonal e teoria da poesia oral: de Mégara Hibleia a Túrio / Orthogonal technique and oral poetry: from Megara Hyblaea to Thuruoi

Peixoto, Renan Falcheti 24 August 2017 (has links)
distribuída em uma moldura interpretativa criada por duas cidades separadas em suas respectivas fundações mais ou menos três séculos. A pólis arcaica de Mégara Hibleia e a pólis clássica de Túrio oferecem as maiores referências da presente pesquisa, cuja intenção é analisar o fenômeno da organização ortogonal através da teoria da poesia oral como apresentada nos estudos comparativos de Milman Parry e Albert Lord. A pesquisa etnográfica de Parry e Lord no começo do século XX com bardos iugoslavos abriu todo um novo e inspirador campo de estudos no âmbito da composição e recepção dos poemas homéricos. Com tal perspectiva, se demonstrará nas páginas seguintes um método de planejamento sem que haja o desenho de planos. Um planejamento que utiliza como recurso de composição fórmulas aritméticas que definem as proporções entre os elementos do sistema. Iniciando o problema com as evidências literárias sobre Hipodamo de Mileto, coroado por uma corrente historiográfica como primus inventor do método urbano ortogonal, se descortinará uma tradição anônima secular derivada da prática de artífices que não escreveram uma linha a respeito de sua técnica. As fórmulas ortogonais constituem medidas co-dimensionadas entre os lados do lote da casa, do quarteirão e da largura das ruas cristalizados ao longo do tempo na escansão dos quarteirões. Tomando-se miras ópticas e alinhando cordas ao longo de estradas seria possível - como em um esquadro - iniciar dois vetores das fórmulas aritméticas então traduzidas em formas geométricas. Será argumentado na análise detalhada da forma de Mégara Hibleia contra a hipótese de que exista no período arcaico a concepção de um módulo abstrato e a priori. A cidade ortogonal arcaica não é um plano-mestre pensado como um conjunto que precede suas partes. O uso dos princípios da ortogonalidade ao longo do tempo, no entanto, contribuem para o surgimento de novas fórmulas de unidades maiores que em cidades como Túrio consignam dentro de sua área o agrupamento de um dado número de quarteirões. Isto é o indício de que a cidade ortogonal comensura-se então como um conjunto articulado de partes. Ao questionar a leitura moderna que, sob um paradigma literário, vê nos planos e desenhos de reconstituição da malha original das cidades ortogonais um produto de um exercício por excelência abstrato, mental e a priori, se discutirá, por consequência, a ontologia do artefato arqueológico, os fundamentos epistemológicos da arqueologia que, desde seu vir-a-ser como disciplina acadêmica, se ampara de uma série de ferramentas interpretativas herdadas da cosmologia moderna ocidental. O texto circulará, portanto, em vias interdisciplinares entre arqueologia, filologia, filosofia, sociologia, antropologia e história da arte. / The Greek orthogonal technique, especially in the urban contexts of Sicily and south Italy (Magna Graecia), could be distributed in a interpretative frame created by the archaeological tale of two cities separated in its foundations more or less three hundred years. The Archaic polis of Megara Hyblaea and the Classical polis of Thurioi offer the two major references of the present research which intends to analyze the phenomenon of orthogonal organization through the oral poetry theory as presented in the comparative studies of Milman Parry and Albert Lord. The ethnographic research of Parry and Lord in the earlier twentieth century with Yugoslavian singers opens a new and inspiring field on the composition and reception of the Homeric poems. With this perspective, it will be demonstrate in the following pages a planning method without any design plans. A planning that uses as compositional resources arithmetical formulas that define the proportional dimensions between the elements of the system. Initiating the subject with the literary evidences about Hipodamus of Miletus, crowned by a historiographical current as primus inventor of the orthogonal method, will be uncovered the anonymous secular tradition derived from the practice of craftsmen who did not write a single word about their techniques. The orthogonal formulas constitute co-dimensioned measures between the sides of the house lot, the block and the width of streets crystallized over time in the scansion of the blocks. Taking optical sights and aligning ropes along roads would be possible - as in a square - to start two vectors from the arithmetical formulas then translated in geometrical forms. It will be argued in the detailed analysis of Megara Hyblaea\'s layout against the hypothesis that there is in the Archaic period a conception of an abstract and a priori module. The orthogonal Archaic city it is not a master plan thought as a set which precedes its parts. The continued use of the orthogonal principles over time, however, contribute to the emergence of new formulas of larger unities which in cities like Thurioi consigns inside its area the grouping of a given number of blocks. This is a sign of a notion then that the orthogonal city is co-measured from a set articulated of parts. By questioning the modern lecture which, under a literary paradigm, sees the reconstituted plans and drawings of an original orthogonal grid a byproduct of an abstract, mental and a priori exercise, it will be discussed, by consequence, the ontology of the archaeological artifact, the archaeology\'s epistemological fundaments that, since its becoming as an academic discipline, relies on a series of interpretative tools inherited from modern Western cosmology. It will be circulate, therefore, in interdisciplinary roads between archaeology, philology, philosophy, sociology, anthropology and art history.
577

"Geometria das singularidades de projeções" / Geometry of singularities of projections

Dias, Fabio Scalco 16 September 2005 (has links)
Neste trabalho estudamos as singularidades de projeções no plano de curvas genéricas, introduzindo uma nova relação de equivalência para germes e multigermes de curvas planas, denominada A_h-equivalência. / In this work singularities of projections to the plane of curves are studied. We introduce a new equivalence relation for germs of plane curves, called A_h-equivalence.
578

Comparing two populations using Bayesian Fourier series density estimation / Comparação de duas populações utilizando estimação bayesiana de densidades por séries de Fourier

Inácio, Marco Henrique de Almeida 12 April 2017 (has links)
Given two samples from two populations, one could ask how similar the populations are, that is, how close their probability distributions are. For absolutely continuous distributions, one way to measure the proximity of such populations is to use a measure of distance (metric) between the probability density functions (which are unknown given that only samples are observed). In this work, we work with the integrated squared distance as metric. To measure the uncertainty of the squared integrated distance, we first model the uncertainty of each of the probability density functions using a nonparametric Bayesian method. The method consists of estimating the probability density function f (or its logarithm) using Fourier series {f0;f1; :::;fI}. Assigning a prior distribution to f is then equivalent to assigning a prior distribution to the coefficients of this series. We used the prior suggested by Scricciolo (2006) (sieve prior), which not only places a prior on such coefficients, but also on I itself, so that in reality we work with a Bayesian mixture of finite dimensional models. To obtain posterior samples of such mixture, we marginalize out the discrete model index parameter I and use a statistical software called Stan. We conclude that the Bayesian Fourier series method has good performance when compared to kernel density estimation, although both methods often have problems in the estimation of the probability density function near the boundaries. Lastly, we showed how the methodology of Fourier series can be used to access the uncertainty regarding the similarity of two samples. In particular, we applied this method to dataset of patients with Alzheimer. / Dadas duas amostras de duas populações, pode-se questionar o quão parecidas as duas populações são, ou seja, o quão próximas estão suas distribuições de probabilidade. Para distribuições absolutamente contínuas, uma maneira de mensurar a proximidade dessas populações é utilizando uma medida de distância (métrica) entre as funções densidade de probabilidade (as quais são desconhecidas, em virtude de observarmos apenas as amostras). Nesta dissertação, utilizamos a distância quadrática integrada como métrica. Para mensurar a incerteza da distância quadrática integrada, primeiramente modelamos a incerteza sobre cada uma das funções densidade de probabilidade através de uma método bayesiano não paramétrico. O método consiste em estimar a função de densidade de probabilidade f (ou seu logaritmo) usando séries de Fourier {f0;f1; :::;fI}. Atribuir uma distribuição a priori para f é então equivalente a atribuir uma distribuição a priori aos coeficientes dessa serie. Utilizamos a priori sugerida em Scricciolo (2006) (priori de sieve), a qual não coloca uma priori somente nesses coeficientes, mas também no próprio I, de modo que, na realidade, trabalhamos com uma mistura bayesiana de modelos de dimensão finita. Para obter amostras a posteriori dessas misturas, marginalizamos o parâmetro (discreto) de indexação de modelos, I, e usamos um software estatístico chamado Stan. Concluímos que o método bayesiano de séries de Fourier tem boa performance quando comparado ao de estimativa de densidade kernel, apesar de ambos os métodos frequentemente apresentarem problemas na estimação da função de densidade de probabilidade perto das fronteiras. Por fim, mostramos como a metodologia de series de Fourier pode ser utilizada para mensurar a incerteza a cerca da similaridade de duas amostras. Em particular, aplicamos este método a um conjunto de dados de pacientes com doença de Alzheimer.
579

Drugs of the Future - Bispecific Antibodies : An investigaion of future development needs

Svahn, Carl Fabian, Khan, Anisha, Wahlsten, Amanda, Larsson, Terese, Koivula, Therese, Andersson, Thomas January 2019 (has links)
This report reviews the field of bispecific antibodies, artificially engineered antibodies thathave the ability to bind two or more different antigen simultaneously. Historical as well asrecently developed techniques are demonstrated, together with formats in preclinical andclinical development. We studied the field with the future needs of the developers in mind,when it comes to the processes and tools that can be offered by GE Healthcare BiosciencesAB. The development of bispecific antibodies gave rise to new challenges and product-relatedimpurities, which are handled by various methods. We argue for, based on the formats inclinical and preclinical development, that the methods already used to purify monospecificantibodies remain the most successful methods for the purification of bispecific antibodies.This, together with the design strategies that resolve the initial bottle-necks, ensures that theneeds of the developers are met to the same extent as for monoclonal antibodies. The methodsand formats demonstrated here do not represent all that are available or under trial.
580

Performance evaluation of OFDM de-modulator with various multiplier architectures for UWB system. / Performance evaluation of orthogonal frequency division multiplexing de-modulator with various multiplier architectures for ultra wide band system

January 2010 (has links)
Chan, Pui Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 81-83). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgement --- p.iv / Contents --- p.v / Chapter I. --- Introduction --- p.1 / Chapter II. --- Details of UWB System --- p.3 / Background --- p.3 / Technical Information --- p.3 / Applications --- p.11 / Chapter III. --- Theoretical Explanation on Orthogonal Frequency Division Multiplexing (OFDM) Technology --- p.13 / Chapter IV. --- Design of OFDM De-modulator --- p.21 / Multipath Delay Commutator (MDC) --- p.24 / Single-path Delay Feedback (SDF) --- p.25 / Multipath Delay Feedback (MDF) --- p.27 / Chapter V. --- Designs of Multipliers in UWB FFT module --- p.33 / Twiddle Factor Multiplication - Group 1 --- p.33 / Twiddle Factor Multiplication - Group 2 --- p.34 / Twiddle Factor Multiplication - Group 3 --- p.45 / Baugh-Wooley Algorithm --- p.46 / Modified-Booth Algorithm --- p.47 / Hardware Architecture of Multipliers --- p.54 / Partial Product Accumulator - Array Architecture --- p.55 / Partial Product Accumulator - Tree Architecture --- p.59 / Fixed-width Multiplier --- p.61 / Chapter VI. --- Comparison Methodology --- p.65 / Standard Cell Design Flow --- p.66 / FPGA Design Flow --- p.69 / Chapter VII. --- Simulation Results and Discussion --- p.71 / Simulation results of FFT module using Standard Cell Methodology --- p.71 / Simulation results of FFT module using FPGA Methodology --- p.74 / Discussion on Simulation results of FFT module using ASIC and FPGA Methodology --- p.77 / Area / Slice Usage --- p.77 / Power Consumption --- p.77 / APS/SPS --- p.78 / General Guidelines For Designing FFT Module For Other Systems --- p.78 / Chapter VIII. --- Conclusion --- p.80 / Chapter IX. --- Future Works --- p.80 / Reference --- p.81

Page generated in 0.0631 seconds