Renormalization of the S parameter in holographic models of electroweak symmetry breaking

We show that the S parameter is not finite in theories of electroweak symmetry breaking in a slice of anti-de Sitter five-dimensional space, with the light fermions localized in the ultraviolet. We compute the one-loop contributions to S from the Higgs sector and show that they are logarithmically dependent on the cutoff of the theory. We discuss the renormalization of S, as well as the implications for bounds from electroweak precision measurements on these models. We argue that, although in principle the choice of renormalization condition could eliminate the S parameter constraint, a more consistent condition would still result in a large and positive S. On the other hand, we show that the dependence on the Higgs mass in S can be entirely eliminated by the renormalization procedure, making it impossible in these theories to extract a Higgs mass bound from electroweak precision constraints.

Temperature effects on a network of dissipative quantum harmonic oscillators: collective damping and dispersion processes

In this paper we extend the results presented in (de Ponte, Mizrahi and Moussa 2007 Phys. Rev. A 76 032101) to treat quantitatively the effects of reservoirs at finite temperature in a bosonic dissipative network: a chain of coupled harmonic oscillators whatever its topology, i.e., whichever the way the oscillators are coupled together, the strength of their couplings and their natural frequencies. Starting with the case where distinct reservoirs are considered, each one coupled to a corresponding oscillator, we also analyze the case where a common reservoir is assigned to the whole network. Master equations are derived for both situations and both regimes of weak and strong coupling strengths between the network oscillators. Solutions of these master equations are presented through the normal ordered characteristic function. These solutions are shown to be significantly involved when temperature effects are considered, making difficult the analysis of collective decoherence and dispersion in dissipative bosonic networks. To circumvent these difficulties, we turn to the Wigner distribution function which enables us to present a technique to estimate the decoherence time of network states. Our technique proceeds by computing separately the effects of dispersion and the attenuation of the interference terms of the Wigner function. A detailed analysis of the dispersion mechanism is also presented through the evolution of the Wigner function. The interesting collective dispersion effects are discussed and applied to the analysis of decoherence of a class of network states. Finally, the entropy and the entanglement of a pure bipartite system are discussed.

Investigation of interfacial processes at tetraruthenated zinc porphyrin films using electrochemical surface plasmon resonance and electrochemical quartz crystal microbalance

In the present work we describe the investigation of interfacial and superficial processes on tetraruthenated zinc porphyrin (ZnTRP) films immobilized on gold electrode surface. In situ and real time measurements employing electrochemical surface plasmon resonance (ESPR)and electrochemical quartz crystal microbalance (EQCM) have given new insights into the electrochemical oxidation of ferrocyanide and phenolic compounds (acetaminophen, dopamine, and catechol) on ZnTRP modified electrodes. The decrease of diode like behavior in the presence of such phenolic species in contrast with ferrocyanide was clearly assigned to the inclusion of those species in the porphyrin film, creating new conduction pathways connecting the gold electrode surface with the film/solution interface. In fact, there are evidences that they can intercalate in the film (catechol > dopamine > acetaminophen), whereas ferrocyanide is completely excluded. Accordingly, the molecular size may play a fundamental role in such a process. (C) 2009 Published by Elsevier Ltd.

Experimental and computational investigation of the roll forming process

One of the first questions to consider when designing a new roll forming line is the number of forming steps required to produce a profile. The number depends on material properties, the cross-section geometry and tolerance requirements, but the tool designer also wants to minimize the number of forming steps in order to reduce the investment costs for the customer. There are several computer aided engineering systems on the market that can assist the tool designing process. These include more or less simple formulas to predict deformation during forming as well as the number of forming steps. In recent years it has also become possible to use finite element analysis for the design of roll forming processes. The objective of the work presented in this thesis was to answer the following question: How should the roll forming process be designed for complex geometries and/or high strength steels? The work approach included both literature studies as well as experimental and modelling work. The experimental part gave direct insight into the process and was also used to develop and validate models of the process. Starting with simple geometries and standard steels the work progressed to more complex profiles of variable depth and width, made of high strength steels. The results obtained are published in seven papers appended to this thesis. In the first study (see paper 1) a finite element model for investigating the roll forming of a U-profile was built. It was used to investigate the effect on longitudinal peak membrane strain and deformation length when yield strength increases, see paper 2 and 3. The simulations showed that the peak strain decreases whereas the deformation length increases when the yield strength increases. The studies described in paper 4 and 5 measured roll load, roll torque, springback and strain history during the U-profile forming process. The measurement results were used to validate the finite element model in paper 1. The results presented in paper 6 shows that the formability of stainless steel (e.g. AISI 301), that in the cold rolled condition has a large martensite fraction, can be substantially increased by heating the bending zone. The heated area will then become austenitic and ductile before the roll forming. Thanks to the phenomenon of strain induced martensite formation, the steel will regain the martensite content and its strength during the subsequent plastic straining. Finally, a new tooling concept for profiles with variable cross-sections is presented in paper 7. The overall conclusions of the present work are that today, it is possible to successfully develop profiles of complex geometries (3D roll forming) in high strength steels and that finite element simulation can be a useful tool in the design of the roll forming process.

Um Estudo sobre Rent-Seeking e seus Efeitos sobre a Acumulação de Capital e Bem Estar

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On the statistical estimation of diffusion processes: a survey

Data available on continuos-time diffusions are always sampled discretely in time. In most cases, the likelihood function of the observations is not directly computable. This survey covers a sample of the statistical methods that have been developed to solve this problem. We concentrate on some recent contributions to the literature based on three di§erent approaches to the problem: an improvement of the Euler-Maruyama discretization scheme, the use of Martingale Estimating Functions and the application of Generalized Method of Moments (GMM).

On the statistical estimation of diffusion processes - a partial survey

Data available on continuous-time diffusions are always sampled discretely in time. In most cases, the likelihood function of the observations is not directly computable. This survey covers a sample of the statistical methods that have been developed to solve this problem. We concentrate on some recent contributions to the literature based on three di§erent approaches to the problem: an improvement of the Euler-Maruyama discretization scheme, the employment of Martingale Estimating Functions, and the application of Generalized Method of Moments (GMM).

New models of old(?) payment questions

Is private money feasible and desirable? In its absence, is there a central bank policy that partially or fully substitutes for private money? In this paper, some recent modeling ideas about how to address these questioned are reviewed and applied. The main ideas are that people cannot commit to future actions and that their histories are to some extent unknown - are not common knowledge. Under the additional assumption that the private monies issued by diferent people are distinct, a strong recognizability assumption, it is shown that there is a role for private money.

Constituição, finanças públicas e desempenho econômico

Esta pesquisa mostra que há uma relação entre a economia e a política no estudo da escolha pública e coletiva. Mais precisamente, eu defendo que a política governamental (ou planejamento estratégico) é influenciada pelo processo político e depende da organização da sociedade em grupos de pressão caçadores de renda. A primeira parte analisa as limitações exógenas à ação individual no Estado; a segunda parte refere-se ao problema de agenciamento, estudando o papel das limitações internas à ação individual dentro da organização. A conclusão discute como essa visão sobre política governamental introduzida aqui deve complementar o ponto de vista tradicional sobre a análise do processo político e as ações dos agentes públicos.

Caçadores de renda: uma investigação sobre a teoria do rent seeking

Este trabalho apresenta uma investigação sobre a teoria do Rent Seeking. Define o conceito de caçar renda e esclarece a diferença entre caçar renda e transferir renda. Mostra que o comportamento caçador de renda é determindado pela lógica da ação coletiva. Esta dissertação ainda analisa os impactos de bem estar social provocados por este tipo de comportamento. A evolução do processo investigativo revelou que o estudo do tema passa necessariamente pela análise da escassez da oferta arbitrariamente estabelecida, seja através da criação e manutenção artificial de monopólios, seja por meio de restrições ao comércio internacional

Models of complexity in Robert Coover's John's wife and the adventures of Lucky Pierre

This doctoral dissertation analyzes two novels by the American novelist Robert Coover as examples of hypertextual writing on the book bound page, as tokens of hyperfiction. The complexity displayed in the novels, John's Wife and The Adventures of Lucky Pierre, integrates the cultural elements that characterize the contemporary condition of capitalism and technologized practices that have fostered a different subjectivity evidenced in hypertextual writing and reading, the posthuman subjectivity. The models that account for the complexity of each novel are drawn from the concept of strange attractors in Chaos Theory and from the concept of rhizome in Nomadology. The transformations the characters undergo in the degree of their corporeality sets the plane on which to discuss turbulence and posthumanity. The notions of dynamic patterns and strange attractors, along with the concept of the Body without Organs and Rhizome are interpreted, leading to the revision of narratology and to analytical categories appropriate to the study of the novels. The reading exercised throughout this dissertation enacts Daniel Punday's corporeal reading. The changes in the characters' degree of materiality are associated with the stages of order, turbulence and chaos in the story, bearing on the constitution of subjectivity within and along the reading process. Coover's inscription of planes of consistency to counter linearity and accommodate hypertextual features to the paper supported narratives describes the characters' trajectory as rhizomatic. The study led to the conclusion that narrative today stands more as a regime in a rhizomatic relation with other regimes in cultural practice than as an exclusively literary form and genre. Besides this, posthuman subjectivity emerges as class identity, holding hypertextual novels as their literary form of choice.

A economia política da corrupção: o escândalo do orçamento

A abertura democrática no Brasil criou um otimismo com a possibilidade do resolver seus problemas crônicos como inflação e corrupção. Foi feita uma panaceia sobre democracia; da democracia surgiriam as soluções para todos os males. Entretanto, a história recente mostra que a democracia não coincide com a eliminação da corrupção e inflação crônicas. Ao contrário, a corrupção causou danos a algumas instituições fundamentais da democracia como o Presidente e o Confresso. Infelizmente, a corrupção é muito perigosa para a democracia. Como observou Tocqueville, com sua perspicácia natural, o povo até tolera a corrupção numa tirania, por ser um fato comum neste tipo de governo. Não obstante, em uma democracia, a corrupção é inaceitável porque pessoas comuns são eleitas para representar cidadãos, e não para trabalhar contra eles. Os últimos escândalos envolvendo corrupção no Brasil, como o caso Collor e principalmente o uso “inadequado” do orçamento nacional foram importantes porque mostraram a incapacidade da sociedade para controlar este fator de risco institucional.. É interessante notar que em outros grandes casos de corrupção na América Latina, como no Gráu, Cuba , Portillo, México ou mesmo na Venezuela, durante os eufóricos anos 70, a situação econômica e até mesmo política não eram ruins. Entretanto, no Brasil, aparentemente, a corrupção política cresceu num período de crises estruturais. Infelizmente este fato tem um resultado considerável: o crescente pessimismo do homem comum sobre o futuro. Entretanto a corrupção pode ser estudada cientificamente. Pode ser vista como uma escolha racional de comportamento compelido por instituições e esquemas de incentivos. Talvez alguns resultados interessantes possam emergir deste tipo de especulação histórica e teórica sobre o comportamento corrupto. Este é o maior objetivo deste estudo.