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  • 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.
31

Régulation épigénétique de la machinerie de transcription de l'ARN polymérase III par l'histone désacétylase SIRT1

Oury, Julien 28 September 2012 (has links) (PDF)
SIRT1, appartenant à la famille des sirtuines, est une déacétylase NAD-dépendante, jouant un rôle essentiel dans le contrôle de l'expression génique. En plus de modifier les histones, SIRT1 peut affecter l'activité de certains facteurs de transcription et leurs gènes cibles. Une question fondamentale est de comprendre le mécanisme moléculaire par lequel SIRT1 contrôle l'expression des gènes impliqués dans la prolifération cellulaire et le métabolisme énergétique. Pour identifier les partenaires protéiques de SIRT1, nous avons utilisé la méthode de purification TAP-TAG à partir d'une fraction nucléaire soluble et d'une fraction ancrée à la chromatine de cellules Mef exprimant stablement une copie ectopique de SIRT1 (e-SIRT1). Nous avons ainsi pu identifier un complexe SIRT1 associé à la fois au facteur de prolifération cellulaire Ki67, et à la sous-unité TFIIIC, nécessaire à l'assemblage du complexe de pré-initiation de l'ARN Polymérase III. En délétant sirt1, et en inhibant spécifiquement l'expression de Ki67, nous avons montré que la machinerie de transcription de l'ARN Polymérase III et la prolifération cellulaire étaient fortement affectées. L'ensemble de mes résultats démontre très clairement que SIRT1, Ki67, et TFIIIC sont au sein d'un même complexe protéique, SIRT1 et Ki67 agissant de manière coordonnée pour réguler le niveau d'expression des SINEs et des LINEs, transcrits issus de la machinerie de transcription de l'ARN Polymérase III.
32

Boundary sinh-Gordon model and its supersymmetric extension

Ablikim, Medina January 1999 (has links)
Three different aspects of the sinh-Gordon model are explored in this thesis. We begin, in chapter one, with a summary of the model and the necessary background. Chapter two studies the model with two boundary conditions. Two approaches are presented to investigate the reflection factors off the boundaries and the energy of the theory. In chapter three, perturbation theory is developed to study the theory with one general boundary condition. A contribution to the quantum reflection factor is obtained and compared with the result obtained for the special boundary condition. Chapters four and five investigate the supersymmetric extension of the model in the presence of a single boundary. Firstly, the classical limits of the supersymmetric reflection matrices are checked. The exact reflection factors are studied perturbatively up to the second order of the coupling constant. Secondly, the perturbation theory and the path integral formalism are employed in the supersymmetric model to study the quantum reflection factors. We conclude with a brief sixth chapter describing the outlook for further investigations.
33

Integrable quantum field theories, in the bulk and with a boundary

Mattsson, Peter Aake January 2000 (has links)
In this thesis, we consider the massive field theories in 1+1 dimensions known as affine Toda quantum field theories. These have the special property that they possess an infinite number of conserved quantities, a feature which greatly simplifies their study, and makes extracting exact information about them a tractable problem. We consider these theories both in the full space (the bulk) and in the half space bounded by an impenetrable boundary at x = 0. In particular, we consider their fundamental objects: the scattering matrices in the bulk, and the reflection factors at the boundary, both of which can be found in a closed form. In Chapter 1, we provide a general introduction to the topic before going on, in Chapter 2, to consider the simplest ATFT—the sine-Gordon model—with a boundary. We begin by studying the classical limit, finding quite a clear picture of the boundary structure we can expect in the quantum case, which is introduced in Chapter 3. We obtain the bound-state structure for all integrable boundary conditions, as well as the corresponding reflection factors. This structure turns out to be much richer than had hitherto been imagined. We then consider more general ATFTs in the bulk. The sine-Gordon model is based on a(^(1))(_1), but there is an ATFT for any semi-simple Lie algebra. This underlying structure is known to show up in their S-matrices, but the path back to the parameters in the Lagrangian is still unclear. We investigate this, our main result being the discovery of a "generalised bootstrap" equation which explicitly encodes the Lie algebra into the S-matrix. This leads to a number of new S-matrix identities, as well as a generalisation of the idea that the conserved charges of the theory form an eigenvector of the Cartan matrix. Finally our results are summarised in Chapter 5, and possible directions for further study are highlighted.
34

A reincidência do trabalhador no Programa Seguro-Desemprego : o caso dos trabalhadores atendidos pelo SINE e o papel dos agentes de atendimento na implementação do programa no Distrito Federal

Magalhães, Sílvia Marcela de Oliveira 04 November 2015 (has links)
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Educação, Departamento de Pós-Graduação, Mestrado Profissional em Educação, 2015. / Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2016-12-22T16:01:34Z No. of bitstreams: 1 2015_SílviaMarceladeOliveiraMagalhães.pdf: 1254145 bytes, checksum: 5db24681fd7453a6a49a8c3eaffa3b94 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2017-02-14T20:37:44Z (GMT) No. of bitstreams: 1 2015_SílviaMarceladeOliveiraMagalhães.pdf: 1254145 bytes, checksum: 5db24681fd7453a6a49a8c3eaffa3b94 (MD5) / Made available in DSpace on 2017-02-14T20:37:44Z (GMT). No. of bitstreams: 1 2015_SílviaMarceladeOliveiraMagalhães.pdf: 1254145 bytes, checksum: 5db24681fd7453a6a49a8c3eaffa3b94 (MD5) / Esta dissertação trata da reincidência dos trabalhadores no Programa Seguro-Desemprego atendidos pelo Sistema Nacional de Emprego (SINE) do Distrito Federal. Os objetivos do estudo são: a) descrever modelos de políticas públicas de emprego existentes em alguns países e no Brasil; b) analisar a atuação dos agentes de atendimento do Sistema Nacional de Emprego (SINE) na implementação do Programa Seguro-Desemprego; c) analisar o perfil e as trajetórias profissionais dos trabalhadores reincidentes no Programa Seguro-Desemprego; d) propor um planejamento profissional para o trabalhador reincidente no Programa Seguro-Desemprego. Assim sendo, a pesquisa se baseou nos conceitos de políticas públicas de emprego, especificamente na importância da integração entre políticas passivas e ativas de emprego propostas pelo conceito de Sistema Público de Emprego descrito pela Organização Internacional do Trabalho (OIT); adotou a combinação entre as metodologias qualitativa e quantitativa buscando implementar uma pesquisa explicativa, utilizando as técnicas de observação nos postos do SINE e entrevistas com agentes de atendimentos e trabalhadores beneficiários do Programa Seguro-Desemprego. Outro objetivo da pesquisa foi identificar o papel do SINE na implementação do Programa Seguro-Desemprego, a partir do qual foi possível perceber que devido a forma como as agências são organizadas atualmente no Distrito Federal, os agentes de atendimento não exercem grande influência na reincidência do trabalhador, já que o mesmo recorre ao SINE somente para a habilitação do seguro-desemprego e em busca de vaga de emprego, e que ambos os atendimentos são rápidos e despersonalizados. Diante dos dados coletados, a pesquisa identificou que a reincidência é ocasionada por muitos fatores, e que as trajetórias pessoais e profissionais dos trabalhadores são o menor fator que influencia a reincidência do trabalhador no programa, um dos fatores que inferem essa tese é o alto nível de escolaridade dos trabalhadores entrevistados, sugerindo que essa não tem relação direta com a empregabilidade. Os fatores que mais justificam a reincidência no programa estão relacionados a dinâmica do mercado de trabalho no Brasil, pois a falência de empresas, corte coletivo de funcionários e os contratos temporários somam quase metade dos motivos de demissão dos trabalhadores, mostrando que a rotatividade do mercado de trabalho é um dos principais fatores de reincidência no programa. Foram ainda encontrados muitos casos de “acordo” entre empregado e empregador para o recebimento dos benefícios, o que possibilita um grande aumento na reincidência. / This dissertation deals with the recurrence of workers in the Unemployment Insurance Program attended by the National Employment System (SINE) of the Federal District. The objectives of the study are: a) describe public policy models of existing jobs in some countries and in Brazil; b) analyze the activities of agents call the National Employment System (SINE) in implementing the Unemployment Insurance Program; c) to analyze the profile and professional careers of repeat offenders workers in the Unemployment Insurance Program; d) to propose a professional planning for the defaulter worker in the Unemployment Insurance Program. Therefore, the research was based on the concepts of public employment policies, specifically the importance of the integration of passive and active employment policies proposed by the Public Employment System concept described by the International Labour Organization (ILO); adopted the combination of qualitative and quantitative methodologies seeking to implement an explanatory research using the techniques of observation in the SINE stations and interviews with agents and beneficiaries of care workers Unemployment Insurance Program. Another objective was to identify the role of SINE in implementing the Unemployment Insurance Program, from which it was revealed that because of the way the agencies are currently organized in the Federal District, the service does not have great influence agents in the recurrence of worker, since it refers to the SINE only for qualification of unemployment insurance and job search vague, and that both treatments are quick and depersonalized. On the collected data, the survey found that recidivism is caused by many factors, and the personal and professional trajectories of workers are the lowest factor influencing worker recurrence in the program, one of the factors that infer this thesis is the high level education of the workers interviewed, suggesting that this is not directly related to employability. The factors that justify the recurrence in the program are related to the dynamics of the labor market in Brazil, since the bankruptcy of enterprises, collective court officials and temporary contracts account for almost half of the workers' dismissal of reasons showing that the turnover of the market work is a major recurrence factors in the program. They were also found many cases of "agreement" between employee and employer to the receipt of benefits, allowing a large increase in recidivism.
35

Defeitos topológicos e cadeias cíclicas de deformação aplicados em diferentes cenários

Chinaglia, Mariana 30 April 2015 (has links)
Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-23T14:20:00Z No. of bitstreams: 1 TeseMC.pdf: 7974204 bytes, checksum: 37e1ce261d2f4d80353e99c7ad41eada (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-26T20:39:24Z (GMT) No. of bitstreams: 1 TeseMC.pdf: 7974204 bytes, checksum: 37e1ce261d2f4d80353e99c7ad41eada (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-26T20:39:29Z (GMT) No. of bitstreams: 1 TeseMC.pdf: 7974204 bytes, checksum: 37e1ce261d2f4d80353e99c7ad41eada (MD5) / Made available in DSpace on 2016-09-26T20:39:36Z (GMT). No. of bitstreams: 1 TeseMC.pdf: 7974204 bytes, checksum: 37e1ce261d2f4d80353e99c7ad41eada (MD5) Previous issue date: 2015-04-30 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / In order to obtain structures known as defects, it was used a systematic procedure which holds cyclic deformation chains. This cyclical procedure enables that the initial defect (used to trigger the chain) is recovered via the process of successive deformations. This technique was applied considering topological kink like defects derived from two models, 4 and sine-Gordon, described by a single real scalar eld. The results show that this procedure can generate simultaneously kink and lump like defects with topological mass satisfying closed relations. After the detailed description and analysis of this method, some of its results were applied in brane scenario, where we studied the quantum problem analogue derived from a metric perturbation. The scenarios includes thick branes results that could support 4-dimensional gravity inside. Finally, we studied the topological origin of vacuum transitions in scenarios supported by double-well potentials. It was found that the Wigner function, constructed by means of the ground and rst excited states (solutions of the normal modes potential spectrum), performs quantum tunneling moving from one minimum to another in the potential. The tunneling analysis was performed by a prescription of the Wigner's function dynamics and the time dependence of stagnation points for an analytical double well potential. / Com a finalidade de obter estruturas conhecidas como defeitos, foi utilizado um procedimento sistemático que encerra cadeias cíclicas de deformações. Esse procedimento ciclico possibilita que o defeito inicial (utilizado para acionar a cadeia) seja recuperado através do processo de deformações sucessivas. Essa técnica foi aplicada considerando-se defeitos topológicos (tipo kink) derivados de dois modelos, __ x4 e sine-Gordon, descritos por um único campo escalar e real. Os resultados encontrados revelam que esse procedimento pode gerar simultaneamente defeitos tipo kink e tipo lump (não topológico) com massas topológicas satisfazendo relações fechadas de vinculo. Após a descriçao e análise detalhadas desse método, alguns de seus resultados foram aplicados em cenário de branas, tencionando-se estudar seu problema quântico derivado de uma perturbação na métrica. O cenário inclui como resultado branas espessas que poderiam sustentar gravidade 4-dimensional em seu interior. Por fim, estudou-se a origem topológica das transições de vácuo em cenários sustentados por potenciais com fundo duplo. Verificou-se que a função de Wigner, construida por meio do estado fundamental e do primeiro estado excitado (soluções do espectro de modos normais do potencial), realiza tunelamento quântico deslocando-se de um minimo ao outro do potencial. A análise do tunelamento foi realizada através de uma prescrição da dinâmica da função de Wigner e da dependência temporal dos pontos de estagnação para um potencial de fundo duplo analitico.
36

The mechanics of incremental sheet forming

Jackson, Kathryn Pamela January 2008 (has links)
Incremental sheet forming (ISF) is a flexible process where an indenter moves over the surface of a sheet of metal to form a 3D shell incrementally by a progression of localised deformation. Despite extensive research into the process, the deformation mechanics is not fully understood. This thesis presents new insights into the mechanics of ISF applied to two groups of materials: sheet metals and sandwich panels. A new system for measuring tool forces in ISF is commissioned. The system uses six loadcells to measure reaction forces on the workpiece frame. Each force signal has an uncertainty of ±15 N. This is likely to be small in comparison to tool forces measured in ISF. The mechanics of ISF of sheet metals is researched. Through-thickness deformation and strains of copper plates are measured for single-point incremental forming (SPIF) and two-point incremental forming (TPIF). It is shown that the deformation mechanisms of SPIF and TPIF are shear parallel to the tool direction, with both shear and stretching perpendicular to the tool direction. Tool forces are measured and compared throughout the two processes. Tool forces follow similar trends to strains, suggesting that shear parallel to the tool direction is a result of friction between the tool and workpiece. The mechanics of ISF of sandwich panels is investigated. The mechanical viability of applying ISF to various sandwich panel designs is evaluated by observing failure modes and damage under two simple tool paths. ISF is applicable to metal/polymer/metal sandwich panels. This is because the cores and faceplates are ductile and largely incompressible, and therefore survive local indentation during ISF without collapse. Through-thickness deformation, tool forces and applicability of the sine law for prediction of wall thickness are measured and compared for a metal/polymer/metal sandwich panel and a monolithic sheet metal. The mechanical results for ISF of sheet metals transfer closely to sandwich panels. Hence, established knowledge and process implementation procedures derived for ISF of monolithic sheet metals may be used in the future for ISF of sandwich panels.
37

Konstrukční studie sinusového čerpadla / Design study of sinus pump

Havlát, Pavel January 2011 (has links)
This dissertation focuses on the construction design of a sine pump. It particularly deals with loss minimisation and strives to solve problems relating to excessive wear of the scrapergate which separates suction and the delivery space. The first part of the dissertation describes a new construction variation of a sine pump and the second part deals with a more detailed study including optimisation of one variation.
38

Solving an inverse problem for an elliptic equation using a Fourier-sine series.

Linder, Olivia January 2019 (has links)
This work is about solving an inverse problem for an elliptic equation. An inverse problem is often ill-posed, which means that a small measurement error in data can yield a vigorously perturbed solution. Regularization is a way to make an ill-posed problem well-posed and thus solvable. Two important tools to determine if a problem is well-posed or not are norms and convergence. With help from these concepts, the error of the reg- ularized function can be calculated. The error between this function and the exact function is depending on two error terms. By solving the problem with an elliptic equation, a linear operator is eval- uated. This operator maps a given function to another function, which both can be found in the solution of the problem with an elliptic equation. This opera- tor can be seen as a mapping from the given function’s Fourier-sine coefficients onto the other function’s Fourier-sine coefficients, since these functions are com- pletely determined by their Fourier-sine series. The regularization method in this thesis, uses a chosen number of Fourier-sine coefficients of the function, and the rest are set to zero. This regularization method is first illustrated for a simpler problem with Laplace’s equation, which can be solved analytically and thereby an explicit parameter choice rule can be given. The goal with this work is to show that the considered method is a reg- ularization of a linear operator, that is evaluated when the problem with an elliptic equation is solved. In the tests in Chapter 3 and 4, the ill-posedness of the inverse problem is illustrated and that the method does behave like a regularization is shown. Also in the tests, it can be seen how many Fourier-sine coefficients that should be considered in the regularization in different cases, to make a good approximation. / Det här arbetet handlar om att lösa ett inverst problem för en elliptisk ekvation. Ett inverst problem är ofta illaställt, vilket betyder att ett litet mätfel i data kan ge en kraftigt förändrad lösning. Regularisering är ett tillvägagångssätt för att göra ett illaställt problem välställt och således lösbart. Två viktiga verktyg för att bestämma om ett problem är välställt eller inte är normer och konvergens. Med hjälp av dessa begrepp kan felet av den regulariserade lösningen beräknas. Felet mellan den lösningen och den exakta är beroende av två feltermer. Genom att lösa problemet med den elliptiska ekvationen, så är en linjär operator evaluerad. Denna operator avbildar en given funktion på en annan funktion, vilka båda kan hittas i lösningen till problemet med en elliptisk ekva- tion. Denna operator kan ses som en avbildning från den givna funktions Fouri- ersinuskoefficienter på den andra funktionens Fouriersinuskoefficienter, eftersom dessa funktioner är fullständigt bestämda av sina Fouriersinusserier. Regularise- ringsmetoden i denna rapport använder ett valt antal Fouriersinuskoefficienter av funktionen, och resten sätts till noll. Denna regulariseringsmetod illustreras först för ett enklare problem med Laplaces ekvation, som kan lösas analytiskt och därmed kan en explicit parametervalsregel anges. Målet med detta arbete är att visa att denna metod är en regularisering av den linjära operator som evalueras när problemet med en elliptisk ekvation löses. I testerna i kapitel 3 och 4, illustreras illaställdheten av det inversa problemet och det visas att metoden beter sig som en regularisering. I testerna kan det också ses hur många Fouriersinuskoefficienter som borde betraktas i regulariseringen i olika fall, för att göra en bra approximation.
39

Investigating Speech Perception in Children With Speech Delay, Dyslexia, and Speech Delay and Dyslexia

Spencer, Lauren Marie 24 May 2023 (has links) (PDF)
Perceptual deficits related to phonology in children with speech delay (SD) and children with dyslexia have been identified in separate lines of research. However, there has only been a small number of studies that have investigated the perceptual deficits of children with SD and/or dyslexia in the same study to better understand the overlap of their speech perception abilities. Children with SD have previously shown deficits perceiving speech stimuli that is acoustically sparse, particularly when stimuli contain speech sounds they do not produce correctly. Yet in contrast to children with dyslexia, children with SD are better able to recover linguistic structure from speech stimuli that preserves global acoustic structure in the absence of spectral detail. Therefore, the purpose of this study is to further investigate how children with SD, dyslexia, SD + dyslexia, and typically developing (TD) peers perceive different types of speech. To do this, we used both vocoded speech and sine-wave speech recognition tasks. In this study, 40 children (ages 7-10 years) with SD, dyslexia, SD + dyslexia, and/or typically developing were presented with both sine-wave and vocoded speech recognition tasks to investigate their speech perception. Findings revealed no differences between groups for both the sine-wave and vocoded speech perception tasks, regardless of SD and/or dyslexia status. Increasing the number of participants or utilizing more sensitive speech perception tasks may provide clinically applicable resources for assessment or intervention. We discuss these findings in the context of previous research literature and also discuss limitations of the current study and future directions for follow-up investigations.
40

Biologic Activity of the Novel SINE Compound KPT-335 Against Canine Melanoma Cell Lines

Breit, Megan N. 15 September 2014 (has links)
No description available.

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