Wir untersuchen die perturbative Quantentheorie verschiedener integrabler Yang-Baxter-Deformationen des freien Superstrings auf AdS-Räumen. Dazu berechnen wir die Zwei-Körper-Streumatrix auf Baum-Niveau auf dem Weltenblatt mit Feynman-Diagramm-Methoden. Die verschiedenen Deformationen sind: (1) Alle abelschen Deformationen von AdS₅ ⨉ S⁵, die die Fixierung der Lichtkegel-Eichung erlauben. Diese sind dual zur nicht-kommutativen Super-Yang-Mills-Theorie und werden äquivalent durch TsT-Transformationen oder verwundene Randbedingungen beschrieben. Wir berechnen die bosonische Streumatrix auf Baum-Niveau für den BMN-String in uniformer Lichtkegel-Eichung. Die Streumatrix wird in den meisten Fällen durch einen Drinfeld-Verwindungen ausgedrückt; in einigen Fällen wird sie stattdessen durch eine verschobene Impulsabhängigkeit ausgedrückt. Abschließend vergleichen wir die aus diesen Ergebnissen abgeleiteten Bethe-Gleichungen mit denen des Modells mit verwundene Randbedingungen und stellen eine perfekte Übereinstimmung fest. Für Deformationen des GKP-Strings können wir aufgrund konzeptioneller Hindernisse keine deformierte Streumatrix um die Null-Cusp-Lösung bestimmen. (2) Die inhomogene oder eta-Deformation von AdS₅ ⨉ S⁵ entsprechend dem fermionischen Dynkin-Diagramm. Wir berechnen die Zwei-Körper-Streumatrix auf Baum-Niveau zu quadratischer fermionischer Ordnung in uniformer Lichtkegel-Eichung. Sie erfüllt die klassische Yang-Baxter-Gleichung, faktorisiert in zwei Blöcke und entspricht der exakten Streumatrix für ein Modell mit trigonometrisch quantendeformierter Symmetrie. (3) Inhomogene bi-Yang-Baxter-Deformationen von AdS₃ ⨉ S³ ⨉ T⁴ für mehrere Dynkin-Diagramme. Wir berechnen die Zwei-Körper-Streumatrix auf Baum-Niveau zu quadratischer fermionischer Ordnung in uniformer Lichtkegel-Eichung. Alle Deformationen ergeben die gleiche Streumatrix, die mit der erwarteten exakten Streumatrix bei trigonometrisch quantendeformierter Symmetrie übereinstimmt. / We study the perturbative quantum theory of various integrable Yang-Baxter deformations of the free superstring on AdS spaces. For this we compute the two-body tree-level scattering matrix on the worldsheet using Feynman diagram methods. The various deformations are: (1) All distinct Abelian deformations of AdS₅ ⨉ S⁵ allowing light-cone gauge fixing. These are dual to noncommutative super Yang-Mills theory and equivalently described through TsT transformations or twisted boundary conditions. We compute the bosonic tree-level scattering matrix for the BMN string in uniform light-cone gauge. The scattering matrix is expressed through a Drinfeld twist for most cases; for some cases it is expressed instead through a shifted momentum dependence. Lastly, we compare the Bethe equations derived from these results to the equations of the model with twisted boundary conditions and find perfect agreement. For deformations of the GKP string we are not able to determine a deformed scattering matrix around the null-cusp solution due to actions incompatible with perturbation theory in momentum space. (2) The inhomogeneous or eta deformation of AdS₅ ⨉ S⁵ corresponding to the fermionic Dynkin diagram. We compute the two-body tree-level scattering matrix up to second order in fermions in uniform light-cone gauge. It satisfies the classical Yang-Baxter equation, factorizes into two blocks and matches the exact scattering matrix for a model with trigonometrically quantum-deformed symmetry. (3) Inhomogeneous bi-Yang-Baxter deformations of AdS₃ ⨉ S³ ⨉ T⁴ for multiple Dynkin diagrams. We compute the two-body tree-level scattering matrix up to second order in fermions in uniform light-cone gauge. All deformations give the same scattering matrix, which matches the expected exact scattering matrix with trigonometrically quantum-deformed symmetry.

The thesis deals with an influence of the errors caused by utilization of the switched-current (SI) approach in the delta-sigma modulators. The basic block of the SI technique is current memory cell (CMC). The analysis of the errors starts with the design of the CMC using CADENCE software and AMIS CMOS 0.7 um technology. Based upon analysis of the CMC no ideal transfer function and advanced techniques of their behavior modeling are depicted. The mathematical models were made and implemented using MATLAB SIMULINK software. The models are very universal. Therefore, it is possible to analyze various structures of the delta-sigma modulators using demanded technology. The influence of the SI technique approach errors sources, on the modulators behavior with the CMC of the 1st and 2nd generation, is concluded at the end.

Σκοπός αυτής της εργασίας είναι να παρουσιάσει την έννοια της πολιτικής ποιότητας «6 Σίγμα» και να αναπτύξει ένα εργαλείο μέτρησης, ένα ερωτηματολόγιο για αυτή. Να εντοπίσει τα κενά που υπάρχουν στην ήδη υπάρχουσα βιβλιογραφία σχετικά με αυτή την έννοια καθώς και να παραθέσει κάποιες προτάσεις για μελλοντικές έρευνες. Τέλος σκοπός της είναι να παρουσιάσει το προφίλ των ελληνικών μεταποιητικών – βιομηχανικών επιχειρήσεων στις οποίες πρόκειται να στοχεύσει το παρόν ερωτηματολόγιο. Μεθοδολογία/προσέγγιση: στην παρούσα εργασία αναπτύσσεται η θεωρία σχετικά με την εφαρμογή της πολιτικής ποιότητας «6 Σίγμα» στις μεταποιητικές επιχειρήσεις. Η συλλογή των στοιχείων έγινε με βάση τη βιβλιογραφική ανασκόπηση και οι λέξεις κλειδιά που χρησιμοποιήθηκαν ήταν: six sigma, critical success factors of six sigma, barriers of six sigma, benefits of six sigma, problem areas of six sigma, lean six sigma, reasons for implementing and not implementing, tools and techniques used by companies, factors for measuring six sigma management activities, και methodology DMAIC. Στα πλαίσια αυτής της εργασίας δημιουργήθηκε ένα δομημένο ερευνητικό ερωτηματολόγιο το οποίο έχει να κάνει με την πολιτική ποιότητας «6 Σίγμα» στις ελληνικές μεταποιητικές – βιομηχανικές επιχειρήσεις. Συμπεράσματα: μετά τη μελέτη αρκετών παρόμοιων ερευνών που έγιναν πάνω στην πολιτική ποιότητας «6 Σίγμα», καταλήγουμε στο συμπέρασμα ότι το παρόν ερωτηματολόγιο θα απευθυνθεί σε επιχειρήσεις που έχουν κάποια εμπειρία στην πολιτική ποιότητας «6 Σίγμα», ή έχουν εφαρμόσει κάποια άλλη στρατηγική ποιότητας (ISO 9000). Επίσης το μέγεθος των επιχειρήσεων στο οποίο θα στοχεύσει θα είναι ΜΜΕ, αφού αποτελούν την πλειοψηφία των ελληνικών επιχειρήσεων. Περιορισμοί: όπως κάθε έρευνα που πραγματοποιείται περιλαμβάνει κάποιους περιορισμούς έτσι και η παρούσα εργασία έχει τους δικούς της. Ο βασικότερος περιορισμός της είναι ότι βασίστηκε μόνο σε βιβλιογραφική ανασκόπηση και δεν απέδειξε τα στοιχεία που παρουσιάζονται μέσα από κάποια έρευνα έστω και πιλοτική. Επιπλέον το παρόν ερωτηματολόγιο αφορά μόνο τις μεταποιητικές – βιομηχανικές επιχειρήσεις. Παρόλα αυτά αυτή η μελέτη απλά αντιπροσωπεύει μια προκαταρκτική μελέτη που αργότερα μπορεί να επεκταθεί. Πρακτικές επιπτώσεις: αυτή η εργασία θα δώσει τη δυνατότητα στους επαγγελματίες «6 Σίγμα» να ελέγξουν κατά πόσο οι ελληνικές μεταποιητικές – βιομηχανικές επιχειρήσεις είναι εξοικειωμένες με την έννοια της πολιτικής ποιότητας «6 Σίγμα» και κατά πόσο την εφαρμόζουν. Αυτό θα μπορέσει να γίνει στο άμεσο μέλλον, αφού το παρόν ερωτηματολόγιο θα χρησιμοποιηθεί σε πιλοτική έρευνα. Πρωτοτυπία – αξία: αυτή η εργασία παρουσιάζει τα κενά που υπάρχουν στην ήδη υπάρχουσα βιβλιογραφία σχετικά με την πολιτική ποιότητας «6 Σίγμα», τα οποία οδηγούν σε πολλές ερευνητικές προτάσεις για το μέλλον. Επίσης αποτελεί την πρώτη απόπειρα προσέγγισης των ελληνικών μεταποιητικών επιχειρήσεων που εφαρμόζουν αυτή την πολιτική ποιότητας. Λέξεις κλειδιά: six sigma, critical success factors of six sigma, barriers of six sigma, benefits of six sigma, problem areas of six sigma, lean six sigma, reasons for implementing and not implementing, tools and techniques used by companies, factors for measuring six sigma management activities, methodology DMAIC, six sigma belt system και manufacturing industry. / The purpose of this project is to present the concept of “six sigma” and develop a measurement tool, a questionnaire, on this. To locate the gaps that may exist in the relevant by now-bibliography and also to give some future research suggestions. Finally its aim is to present the Greek manufacturing industries profile, which the present questionnaire concerns. Methodology/approach: The present project develops the theory which is relevant to the application of “six sigma” in the manufacturing industries. The collection of the data was based on literature reviews and the key words that were used were: six sigma, critical success factors of six sigma, barriers of six sigma, benefits of six sigma, problem areas of six sigma, lean six sigma, reasons for implementing and not implementing, tools and techniques used by companies, factors for measuring six sigma management activities and methodology DMAIC. In the context of this project there was created a structured research questionnaire, relevant to “six sigma” in Greek manufacturing industries. Conclusions: after studying enough similar surveys on “six sigma”, we come to the conclusion that the present questionnaire is addressed to industries that have a certain experience in “six sigma”, or have applied some other quality strategies (ISO 9000). Furthermore the size of the industries at which it aims will be SME, since they are the majority of Greek industries. Research limitations: the present project includes some specific limitations, like every other study that has been realized. The most basic limitation is that it was only based on literature reviews and it didn’t prove the elements that were presented through a study, even a pilot one. Moreover the present questionnaire concerns only the manufacturing industries. Nevertheless this study simply represents a preliminary study that later can be extended. Practical implications: this study will give the capability to the “six sigma” professionals to check how much the manufacturing industries are familiarized to the concept of “six sigma” and how much they apply it. This might happen in the direct future, since the present questionnaire is used in pilot study. Originality/value: this study presents the gaps that exist in the already existing literature relevant to six sigma, which leads to a lot of future research suggestions. Also it is the first attempt to approach Greek manufacturing industries that apply this quality politic. Key words: six sigma, critical success factors of six sigma, barriers of six sigma, benefits of six sigma, problem areas of six sigma, lean six sigma, reasons for implementing and not implementing, tools and techniques used by companies, factors for measuring six sigma management activities, methodology DMAIC, six sigma belt system and manufacturing industry.

A competitividade é um fator de extrema importância para o sucesso das organizações. Os expressivos resultados alcançados pela Motorola e General Electric (GE), por meio do programa Seis Sigma, tem sido uma fonte de inspiração para muitas empresas seguirem o seu exemplo e conseguir maior competitividade. O programa Seis Sigma foi criado e evoluiu em ambiente de manufatura, mas também pode ser aplicado em processos de serviços. Entretanto a aplicação em serviços tem sido feita de forma mais modesta, com menor participação de empresas, e conseqüentemente menor número de casos e relatos divulgados. A literatura menciona que de forma geral o desempenho dos processos de serviços é inferior aos processos de manufatura, e isso pode ser um indicativo de boa oportunidade para a aplicação do programa Seis Sigma. Este trabalho tem como objetivo a análise comparativa da aplicação do programa Seis Sigma em processos de manufatura e serviços, por meio de revisão da literatura e pesquisa com empresas que aplicam o programa, visando entender as diferenças da aplicação em benefício da aplicação em serviços. Os resultados obtidos sugerem indícios de similaridades e diferenças significativas, tais como \"no perfil do Black Belt, nas equipes de projeto, no tempo de execução de um projeto, no uso da CTQ, na disponibilidade e natureza dos dados e na aplicação de técnicas e ferramentas\" que podem ajudar na expansão do programa em serviços, e assim, espera-se que possa motivar mais pesquisas com esse tema de trabalho. / Competitiveness is an important factor for any organization success. The Six Sigma program, which has been used by companies like Motorola and GE since the 1980\'s, has proved to be a successful way to make any company improve all areas of business and therefore, become more competitive. Although it was created and has been growing in manufacturing successfully, its implementation can reach a much wider field of application. In the last few years, some service corporations also been benefited by the use of this program. However, different from manufacturing, its application is less popular and still restricted to few companies that have already implemented it, which explains limited case studies and projects published in the literature. This paper has the goal to perform a comparative analysis of Six Sigma program implementation in manufacturing as well as in services process and consequently, comprehend the differences and advantages of its application in these different fields. The results of this study, which are based on literature review and also a survey with service companies, have led to some significant similarities and differences like the profile of the Black Belt, project time execution, CTQ use, the nature and availability of the data and application of techniques and tools. Further research, can certainly contribute to the expansion of the Six Sigma methodology improvement in service quality.

A citricultura é de grande importância para as atividades agrícolas brasileiras, uma vez que o Brasil é o principal produtor e exportador de suco de laranja. O cancro cítrico, causado pela bactéria Xanthomonas axonopodis pv. citri (Xac) é um grave problema nesse setor, causando um elevado prejuízo na produção de frutos e seus derivados. O fator sigma é a subunidade da RNA polimerase que tem a função de direcionar o núcleo da RNA polimerase a uma classe específica de sequências promotoras. Como a maioria das bactérias sintetiza diversos fatores sigma, essa característica proporciona à bactéria a oportunidade de manutenção basal da sua expressão gênica, assim como, a regulação em resposta a alterações ambientais e a sinais durante o desenvolvimento bacteriano. O genoma de Xac codifica para 14 fatores sigma. Nesse presente trabalho, detectamos interações dos fatores σECF (Xac2814. Xac3989, Xac0922, Xac1319, Xac1380, Xac1682, Xac4129 e Xac2191) e seus fatores anti-σ cognatos (Xac2815. Xac3988, Xac0921, Xac1320, Xac1379, Xac1681, Xac4130 e Xac2192). Além disso, observamos interações entre o fator σFliA (Xac1933) e o anti-σFlgM (Xac1989), seu fator anti-σ cognato. A caracterização das cepas nocautes para alguns fatores σ apontaram o envolvimento do fator σ54Xac1969 no mecanismo de formação de flagelo, a contribuição do fator σECFXac1682 na resposta ao choque térmico e a participação do fator σECFXac2191 no crescimento bacteriano em condições de carência de ferro. / Citriculture is an important sector of the economy of the State of São Paulo. Citrus canker, caused by Xanthomonas axonopodis pv. citri (Xac), is a devastating disease responsible for large agribusiness losses every year. several sigma factors. The sigma factor is the subunit of RNA polymerase that serves to direct the RNA polymerase core to a specific class of promoter sequences. Most bacteria code for more than one sigma factor, which provides the cell with the means by which to maintain basal gene expression while at the same time modulate the expression of specific genes in response in environmental changes and signals during bacterial growth. The Xac genome codes for 14 sigma factors which are the objects of study in this thesis. We demonstrate that many of the sigma factors of the σECF family (Xac2814, Xac3989, Xac0922, Xac1319, Xac1380, Xac1682, Xac4129 e Xac2191) interact with cognate anti- factors (Xac2815, Xac3988, Xac0921, Xac1320, Xac1379, Xac1681, Xac4130 e Xac2192). These sigma-anti-sigma pairs are all coded by neighboring genes. Interactions between the sigma factor σFliA (Xac1933) and anti-σFlgM (Xac1989) were also observed. Xac strains with gene knockouts for several sigma factors were produced. The characterization some these knockout strains point to the involvement of σ54Xac1969 in the biosynthesis of flagella, participation of σECFXac1682 in the ability to survive heat shock and involvement of σECFXac2191 in the response to iron deficiency.

A competitividade é um fator de extrema importância para o sucesso das organizações. Os expressivos resultados alcançados pela Motorola e General Electric (GE), por meio do programa Seis Sigma, tem sido uma fonte de inspiração para muitas empresas seguirem o seu exemplo e conseguir maior competitividade. O programa Seis Sigma foi criado e evoluiu em ambiente de manufatura, mas também pode ser aplicado em processos de serviços. Entretanto a aplicação em serviços tem sido feita de forma mais modesta, com menor participação de empresas, e conseqüentemente menor número de casos e relatos divulgados. A literatura menciona que de forma geral o desempenho dos processos de serviços é inferior aos processos de manufatura, e isso pode ser um indicativo de boa oportunidade para a aplicação do programa Seis Sigma. Este trabalho tem como objetivo a análise comparativa da aplicação do programa Seis Sigma em processos de manufatura e serviços, por meio de revisão da literatura e pesquisa com empresas que aplicam o programa, visando entender as diferenças da aplicação em benefício da aplicação em serviços. Os resultados obtidos sugerem indícios de similaridades e diferenças significativas, tais como \"no perfil do Black Belt, nas equipes de projeto, no tempo de execução de um projeto, no uso da CTQ, na disponibilidade e natureza dos dados e na aplicação de técnicas e ferramentas\" que podem ajudar na expansão do programa em serviços, e assim, espera-se que possa motivar mais pesquisas com esse tema de trabalho. / Competitiveness is an important factor for any organization success. The Six Sigma program, which has been used by companies like Motorola and GE since the 1980\'s, has proved to be a successful way to make any company improve all areas of business and therefore, become more competitive. Although it was created and has been growing in manufacturing successfully, its implementation can reach a much wider field of application. In the last few years, some service corporations also been benefited by the use of this program. However, different from manufacturing, its application is less popular and still restricted to few companies that have already implemented it, which explains limited case studies and projects published in the literature. This paper has the goal to perform a comparative analysis of Six Sigma program implementation in manufacturing as well as in services process and consequently, comprehend the differences and advantages of its application in these different fields. The results of this study, which are based on literature review and also a survey with service companies, have led to some significant similarities and differences like the profile of the Black Belt, project time execution, CTQ use, the nature and availability of the data and application of techniques and tools. Further research, can certainly contribute to the expansion of the Six Sigma methodology improvement in service quality.

In bacteria, the RNA polymerase (RNAP) consists of the following subunits: α2, β, β’, ω and σ. The core RNAP (α2ββ’ω) possesses the polymerising activity and it associates with one of the sigma factors to initiate transcription from a promoter region on the DNA template. All bacteria carry an essential housekeeping sigma factor and a number of extra cytoplasmic function (ECF) sigma factors. During alternate physiological states, a major part of transcriptional regulation is carried out by sigma factors, which act as transcriptional switches, thus, making it possible for bacteria to adapt to varied environmental signals by transcribing the necessary set of genes. Bacteriophages utilise various mechanisms for subverting the bacterial biochemical machinery for their advantage. One such example in E. coli is AsiA protein encoded by an early gene of T4 bacteriophage. Because of its property of binding to σ70, AsiA can inhibit transcription from E. coli promoters bearing –10 and –35 DNA sequences leading to inhibition of growth. σ70 of E. coli is also regulated by a stationary phase specific protein, Rsd, whose major function seems to be helping the cell in switching the transcription in favour of stationary phase genes. In this study we have investigated the mechanism of interaction of T4 AsiA and E. coli Rsd to σ70 of E. coli and also tried to determine the basis of differential inhibition of E. coli growth by AsiA and Rsd. In chapter one we have reviewed the published literature on regulation of transcription in bacteria. Some of the well known mechanisms of regulating gene expression are: DNA supercoiling, two component signal transduction system (TCS), regulation by alarmone ppGpp and 6S RNA, and sigma-antisigma interactions. Most bacteria carry a number of sigma factors and each of them is dedicated to transcribing genes in response to environmental signals. Intracellular levels of sigma factors and their binding affinity to core RNAP are deciding factors for initiating transcription from specific subsets of genes. In addition, sigma factor activity is also controlled by specific proteins, which bind to sigma factors (anti-sigma factors) under certain environmental conditions. A number of anti-sigma factors have been isolated from a variety of bacteria and the mechanisms of action of binding to cognate sigma factors have been worked out by using genetic, biochemical and structural tools. In chapter two, using yeast two hybrid assay (YTH), we have identified the regions of σ70 which interact with AsiA, and it was observed that amino acid residues from 547-603, encompassing region 4.1 and 4.2 are involved in binding to σ70. Interestingly, we found that truncated σ70 fragments lacking the N-terminal regions, apparently bound to AsiA with higher affinity compared to full length σ70. As AsiA expression, because of its transcription inhibitory activity, is inhibitory to E.coli growth, co-expression of the truncated C-terminal σ70 fragments (e.g. residues 493-613, σ70C121), which bind to σ70 with high affinity, could relieve growth inhibition. The complex of GST:AsiA-σ70C121 could be purified from E. coli cells. GST:AsiA purified from E .coli cells was found to be associated with RNAP subunits. Since further studies on this interaction required GST:AsiA preparation devoid of RNAP subunits, we decided to express this protein in S. cerevisiae. Bioinformatics analysis indicated the absence of a σ70 homologue in S.cerevisiae. As expected, GST:AsiA purified from the yeast was found to be free from any RNAP like proteins. The protein purified from yeast was used for in-vitro binding experiments. Our YTH analysis had indicated that deletion a part of region 4.1 or 4.2 of σ70 leads to loss of binding to AsiA. However, the published NMR structure of AsiA in complex with peptides corresponding to region 4 of σ70, showed that either region 4.1 or 4.2 alone can bind to AsiA indicating at the possible existence of two binding sites for AsiA. In order to confirm the physiological significance of this finding, we studied the interaction of truncated σ70 fragments lacking either region 4.1 or 4.2 with AsiA in-vivo in E. coli and in-vitro by affinity pull down assays. It was observed that σ70 fragments lacking either region 4.1 (σ70∆4.1) or 4.2 (σ70∆4.2), did not neutralize the GST:AsiA toxicity, indicating lack of interaction. The affinity purified GST:AsiA from these E. coli cells did not have σ70∆4.1 or σ70∆4.2 associated with it. Similar results were obtained from pull down assays in-vitro, where we found that σ70∆4.1 or σ70∆4.2 do not show any observable interaction with AsiA. This clearly established that the minimum region of σ70 required for physiologically relevant interaction with AsiA consists of both the regions 4.1 and 4.2. Chapter 3 of this thesis has been devoted to this aspect of AsiA-σ70 interaction. Having defined the minimum region of σ70 interacting with AsiA, we sought to identify the regions and amino acid residues of AsiA, which are critical for interaction with σ70. The approach for identification of mutants and their characterisation has been discussed in chapter 4. For this purpose, we made systematic deletions in the N and C-terminal regions of the protein and also isolated random mutants of AsiA, which lack binding to σ70 and thus are non-inhibitory to E. coli growth. It was found that deletion of 5 amino acids from N-terminus and 17 amino acids from C-terminus did not alter the inhibitory activity of AsiA. In contrast, deletion of N-terminal 10 amino residues led to complete loss of activity, while in the C-terminus, a gradual loss of activity was observed when amino acid residues beyond 17 amino acids were deleted. A 34 amino acids C-terminal deletion mutant was found to be completely inactive. E10K mutant was found to be inactive, but changes of E to other amino acids such as S, Y, L, A and Q were tolerated, indicating that negative charge at E10 is not a crucial element for interaction with σ70. Inactive mutants could be overexpressed in E. coli and showed reduced binding in YTH assay and were also poor inhibitors of in-vivo transcription in E. coli. We concluded that the primary σ70 binding site of AsiA is present in the N-terminus, yet C-terminal 64-73 amino acid residues are required for effective binding in-vivo. These studies also correlate the inhibitory potential of AsiA with its σ70 binding proficiency. In chapter 5, we have made a comparative analysis of mechanism of interaction of AsiA and Rsd to E. coli RNAP. Overexpression of Rsd was found to be less inhibitory to E. coli cell growth than that of AsiA. The affinity purified GST-AsiA from E. coli was found to have all the RNAP subunits associated with it, whereas, only σ70 was found to be associated with similarly purified GST:Rsd, pointing towards differences in binding to RNAP. In affinity pull down assays, in-vitro, it was found that both AsiA and Rsd do not show any observable binding to core RNAP. Binding of AsiA to σ70 in holo RNAP led to the formation of a ternary complex, whereas no ternary complex was observed when Rsd was made to interact with holo RNAP. Analysis of protein-protein interaction by YTH showed that region 4.1 and 4.2 are critical for binding of both AsiA and Rsd to σ70. However, in the case of Rsd, the surface of interaction is not limited to this region only and other regions of σ70 make significant contribution to this binding. Possibly, the interaction of Rsd with the core binding regions of σ70 prevents its association with core RNAP. Kinetic analysis of binding by surface plasmon resonance (SPR) showed that binding affinities (Kd) of AsiA and Rsd to σ70 are in similar range. Therefore, we concluded that the ability of AsiA to trap the holo RNAP is, probably, responsible for higher inhibitory activity of this protein compared to that of Rsd. Thus, T4 AsiA and E. coli Rsd, which share regions of interaction on σ70, have evolved differences in their mechanism of binding to RNAP such that T4 AsiA, by trapping the holo RNAP subverts the complete bacterial transcription machinery to transcribe its own genes. Rsd, on the other hand, has evolved to interact primarily with σ70, which favours the utilisation of core RNAP by other sigma factors.

The aim of the master’s thesis is analysis of practical application limits of waste-gate TwinScroll turbocharger located in BMW X6 M vehicle by using DFSS (Design For Six Sigma) tools. The goal is to create a special measurement device for a measurement of waste gate leakage with chance of testing all sorts of characteristics having impact on key parameters of turbocharger.

A citricultura é de grande importância para as atividades agrícolas brasileiras, uma vez que o Brasil é o principal produtor e exportador de suco de laranja. O cancro cítrico, causado pela bactéria Xanthomonas axonopodis pv. citri (Xac) é um grave problema nesse setor, causando um elevado prejuízo na produção de frutos e seus derivados. O fator sigma é a subunidade da RNA polimerase que tem a função de direcionar o núcleo da RNA polimerase a uma classe específica de sequências promotoras. Como a maioria das bactérias sintetiza diversos fatores sigma, essa característica proporciona à bactéria a oportunidade de manutenção basal da sua expressão gênica, assim como, a regulação em resposta a alterações ambientais e a sinais durante o desenvolvimento bacteriano. O genoma de Xac codifica para 14 fatores sigma. Nesse presente trabalho, detectamos interações dos fatores σECF (Xac2814. Xac3989, Xac0922, Xac1319, Xac1380, Xac1682, Xac4129 e Xac2191) e seus fatores anti-σ cognatos (Xac2815. Xac3988, Xac0921, Xac1320, Xac1379, Xac1681, Xac4130 e Xac2192). Além disso, observamos interações entre o fator σFliA (Xac1933) e o anti-σFlgM (Xac1989), seu fator anti-σ cognato. A caracterização das cepas nocautes para alguns fatores σ apontaram o envolvimento do fator σ54Xac1969 no mecanismo de formação de flagelo, a contribuição do fator σECFXac1682 na resposta ao choque térmico e a participação do fator σECFXac2191 no crescimento bacteriano em condições de carência de ferro. / Citriculture is an important sector of the economy of the State of São Paulo. Citrus canker, caused by Xanthomonas axonopodis pv. citri (Xac), is a devastating disease responsible for large agribusiness losses every year. several sigma factors. The sigma factor is the subunit of RNA polymerase that serves to direct the RNA polymerase core to a specific class of promoter sequences. Most bacteria code for more than one sigma factor, which provides the cell with the means by which to maintain basal gene expression while at the same time modulate the expression of specific genes in response in environmental changes and signals during bacterial growth. The Xac genome codes for 14 sigma factors which are the objects of study in this thesis. We demonstrate that many of the sigma factors of the σECF family (Xac2814, Xac3989, Xac0922, Xac1319, Xac1380, Xac1682, Xac4129 e Xac2191) interact with cognate anti- factors (Xac2815, Xac3988, Xac0921, Xac1320, Xac1379, Xac1681, Xac4130 e Xac2192). These sigma-anti-sigma pairs are all coded by neighboring genes. Interactions between the sigma factor σFliA (Xac1933) and anti-σFlgM (Xac1989) were also observed. Xac strains with gene knockouts for several sigma factors were produced. The characterization some these knockout strains point to the involvement of σ54Xac1969 in the biosynthesis of flagella, participation of σECFXac1682 in the ability to survive heat shock and involvement of σECFXac2191 in the response to iron deficiency.

Dans cette thèse, les recherches ont été menées à des niveaux d'abstraction différents pour optimiser le fonctionnement du modulateur ΣΔ passe-haut (PH). Une approche « top-down » est adoptée pour atteindre cet objectif. Au niveau de l'architecture du récepteur RF, le nouvellement créé récepteur Fs/2 est sélectionné pour sa grande compatibilité avec modulateur ΣΔ PH comparé aux architectures de réception: zéro-IF et faible-IF. Après avoir défini la topologie du récepteur, l'architecture du modulateur ΣΔ est adressée. Nous proposons une nouvelle architecture du deuxième ordre dont la fonction de transfert du signal est unitaire. Elle est plus avantageuse que d'autres topologies en termes de complexité et de performance. Puisque le modulateur de second ordre est incapable de fournir les performances requises, les structures en cascade ou MASH pour l'opération PH sont explorées. La topologie GMSCL (Generalized Multi-Stage Closed Loop) est choisie et une technique récemment proposée est appliquée pour linéariser le CNA de retour. En plus, cette technique augmente la plage dynamique du convertisseur. Ensuite, après une analyse comparative approfondie, le meilleur filtre HP est choisie pour ce modulateur. Il a les avantages d'avoir une basse consommation, une superficie réduite et un bruit moins important. Enfin, l'architecture GMSCL PH proposée est validée en CMOS 65nm. Les applications visées sont l'UMTS avec 3.84MHz bande de conversion à 80 dB de la plage dynamique et WiMAX avec 25MHz de bande passante à 52dB de dynamique.