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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.
361

Symétrie électrofaible à la lumière du LHC

Kubik, Bogna 05 October 2012 (has links) (PDF)
Les extensions du Modèle Standard (MS) des particules sont maintenant dans une époque de développement très actif. Les motivations de l'introduction des dimensions supplémentaires sont basées d'une part sur la théorie des cordes qui nécessitent l'existence de nouvelles dimensions pour être cohérent. D'un autre côté ces théories peuvent potentiellement expliquer le problème de hiérarchie, le nombre de générations de fermions ou la stabilité du proton. La caractéristique commune de ces modèles est qu'ils fournissent une nouvelle particule neutre interagissant faiblement - un candidat idéal de la matière noire. Sa stabilité est préservée par la parité KK qui interdit les désintégrations du LKP en particules du MS. La géométrie de l'espace sous-jacent détermine le spectre de particules du modèle donc la masse et le spin du candidat DM, qui à leur tour jouent un rôle clé dans les études phénoménologiques. Nous présentons un modèle à deux dimensions supplémentaires universelles compactifiées sur le plan projectif réel. Cette géométrie particulière permet la définition des fermions chiraux et la stabilité de la matière noire neutre candidat dérive naturellement des propriétés intrinsèques de l'espace sans ajouter de nouvelles symétries ad hoc. Nous présentons le spectre de deux premiers niveaux KK à une boucle. Le spectre au sein de chaque niveau KK est fortement dégénéré ce qui fournie des signatures très intéressantes du modèle. Nous étudions la phénoménologie de la matière noire dans notre modèle pour limiter l'espace des paramètres en comparant nos résultats avec les données de WMAP et les expériences de détection directe. En utilisant les bornes obtenues, nous nous concentrons sur la phénoménologie LHC de notre modèle.
362

A study on the conceptualization and programming of a community-based day training centre in psychiatric rehabilitation

Wong, Lai-ngor, Jenny., 黃麗娥. January 1993 (has links)
published_or_final_version / Social Work / Master / Master of Social Sciences
363

Žemės plutos judesių įvertinimo sudarant geodezinius tinklus tyrimas / Research of the earth crust movement evaluation creating geodetic networks

Kirklytė, Giedrė 05 June 2012 (has links)
Dabartiniai geodinaminiai procesai žemės paviršiuje pasireiškia vertikaliaisiais ir horiznotaliaisiais žemės plutos judesiais. Dėl vykstančių žemės plutos judesių keičiasi geodezinių ženklų padėtis, o dėl šios priežasties matavimų rezultatai bėgant laikui netenka reikalaujamo tikslumo. Darbo tikslas – ištirti vertikaliųjų žemės plutos judesių įtaką vertikaliesiems geodeziniams tinklams (Lietuvos vertikaliojo geodezinio tinklo pirmojo poligono pavyzdžiu). Tyrimo uždaviniai – atlikti literatūros šaltinių apžvalgą ir išnagrinėti dabartinių žemės plutos judesių vertinimo metodikas, atlikti vertikaliųjų žemės plutos judesių įtakos vertikaliajam geodeziniam tinklui tyrimą ekperimentiniame objekte, apibendrinti tyrimo rezultatus bei pateikti išvadas ir rekomendacijas. Tyrimo metodas – ekpserimentiniai ir analitiniai tyrimai. Iš atliktų tyrimų nustatyta, kad dėl vykstančių geodinaminių procesų apskaičiuotų pataisų reikšmė geodeziniams matavimams yra ne mažesnė už normalinių pataisų reikšmę. Įvertinant žemės plutos judesius, geodezinių ženklų aukščiai eksperimentiniame poligone kinta iki 18 mm, o geodinaminės pataisos yra nuo 3 iki 5 kartų didesnės už leistinas paklaidas. Daroma išvada, kad būtina įvertinti dabartinius žemės plutos judesius. / Recent geodynamic processes in the earth's surface appears by horizontal and vertical movements of the earth's crust. Because of these movements, geodetic marks change their position. Geodetic networks and geodetic measurements lose the required accuracy over the time. It is influenced by vertical movements of the earth's crust. Masters thesis aim - to investigate the vertical movements of the earth's crust affect for the vertical geodetic networks (the first polygon of Lithuanian geodetic vertical network). Masters thesis tasks – to make a literature review, examine the earth's crust movements evaluation methodologies, find out how vertical earth’s crust movement influence geodetic measurements, summarize the results and present conclusions and recommendations. Master thesis method – experimental and analytical investigation. Considering the earth's crust movements, the heights of the experimental character of geodesic polygon varies up to 18 mm, and the geodynamic corrections from 3 to 5 times are higher than the allowable correction. To sum up, the vertical earth’s crust movement impact must be evaluated. Structure: introduction, four chapters, conclusions and suggestions, six appendixes.
364

Optimisation of environmental gamma spectrometry using Monte Carlo methods

Hernández Suárez, Francisco Javier January 2002 (has links)
Dissertation in Environmental Physics to be publicly examined in Häggsalen (Ångström Laboratory), Uppsala University, on Friday, November 8, 2002 at 10:00 am for the degree of doctor of philosophy in Physics. The examination will be conducted in English. Gamma spectrometry is one of the tools commonly used for the measurement of various environmental radionuclides. Simultaneous determination of the absolute activity of gamma emitting radiotracers in a wide range of environmental matrices and fractions necessitates proper and accurate evaluation of the sample-to-detector efficiency. Several radiotracers require, in addition, the use of sub-routines for self-absorption corrections. Gamma spectrometry is an important and elegant tool for assessing environmental changes. Optimisation of ultra low-level gamma spectrometry for reliable assessment of such changes requires harmonisation of laboratory needs with sampling and site conditions. Different aspects of the calculation of sample-to-detector efficiencies using empirical and Monte Carlo approaches are discussed here, including the uncertainties related to the simulation of the performance of different HPGe detectors and the effects of the incomplete collection of charges in Ge-crystals. Various simulation codes for the computation of peak efficiencies in planar and well Ge-detectors have been developed from scratch. The results of the simulations have been tested against experimental data and compared to other simulation results obtained with the Monte Carlo N-Particle code (MCNP). The construction of calibration sources with improved absorption and collimation characteristics have been, also, described in this work. These sources have been especially designed for the efficiency calibration of Ge-detectors at energies below 100 keV. Flexible, fully tested and prototype approaches for the evaluation of self-absorption corrections, based on Monte Carlo simulations, are described. Special consideration is given to the problems related to the sample's variability in size, density and composition. Several examples of the absolute and simultaneous determination of environmental multitracers which benefited from self-absorption corrections and the optimised efficiency calibration algorithms are, also, presented and discussed. These examples include, among other things, a comprehensive analysis of the gamma spectrometry of 234Th in a wide range of matrices and the speciation of several radionuclides in sediments from a hard-water lake.
365

Derivatives pricing and term structure modeling

Hinnerich, Mia January 2007 (has links)
<p>Diss. Stockholm : Handelshögskolan, 2007 viii, s. [1]-4: sammanfattning, s. [7]-104: 3 uppsatser</p>
366

Classical and quantum aspects of topological solitons (using numerical methods)

Weidig, Tom January 1999 (has links)
In Introduction, we review integrable and topological solitons. In Numerical Methods, we describe how to minimize functionals, time-integrate configurations and solve eigenvalue problems. We also present the Simulated Annealing scheme for minimisation in solitonic systems. In Classical Aspects, we analyse the effect of the potential term on the structure of minimal- energy solutions for any topological charge n. The simplest holomorphic baby Skyrme model has no known stable minimal-energy solution for n > 1. The one-vacuum baby Skyrme model possesses non-radially symmetric multi-skyrmions that look like 'skyrmion lattices' formed by skyrmions with n = 2. The two-vacua baby Skyrme model has radially symmetric multi- skyrmions. We implement Simulated Annealing and it works well for higher order terms. We find that the spatial part of the six-derivative term is zero. In Quantum Aspects, we find the first order quantum mass correction for the Ф(^4) kink using the semi-classical expansion. We derive a trace formula which gives the mass correction by using the eigenmodes and values of the soliton and vacuum perturbations. We show that the zero mode is the most important contribution. We compute the mass correction of Ф(^4) kink and Sine-Gordon numerically by solving the eigenvalue equations and substituting into the trace formula.
367

Spektrální a transportní vlastnosti korelovaných elektronů v neuspořádaných slitinách / Spectral and transport properties of correlated electrons in disordered alloys

Pokorný, Vladislav January 2013 (has links)
We develop methods how to calculate charge transport in disordered systems applicable in all disorder regimes. They allow to calculate vertex corrections to the electrical conductivity and the diffusion coefficient in models of elastically scattered electrons in the presence of random scatterers. These methods are based on an asymptotic limit to high spatial dimensions. The resulting formulas lead to reliable results free of unphysical behavior, as illustrated on a gallery of numerical examples.
368

Radiação Hawking de um buraco negro BTZ não-comutativo.

CAVALCANTI, Arthur Gonçalves. 09 October 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-10-09T18:55:52Z No. of bitstreams: 1 ARTHUR GONÇALVES CAVALCANTI – DISSERTAÇÃO (PPGFísica) 2016.pdf: 845402 bytes, checksum: dbdfb2a26834c477a45e9e735fa670d3 (MD5) / Made available in DSpace on 2018-10-09T18:55:52Z (GMT). No. of bitstreams: 1 ARTHUR GONÇALVES CAVALCANTI – DISSERTAÇÃO (PPGFísica) 2016.pdf: 845402 bytes, checksum: dbdfb2a26834c477a45e9e735fa670d3 (MD5) Previous issue date: 2016-02 / Capes / A teoria da relatividade geral prevê soluções tipo buraco negro, as quais são caracterizadas pela existência de um horizonte de eventos. Como exemplo, podemos citar a métrica obtida por Bãnados-Teitelboim-Zanelli (BTZ), que é uma solução da gravitação em (2+1)- dimensões, em que se considera uma constante cosmológica negativa. Nos últimos anos, buracos negros não-comutativos têm sido investigados na literatura por muitos autores. Em particular, a métrica BTZ não-comutativa foi obtida considerando-se a equivalência, que existe em três dimensões, entre gravitação e a teoria de Chern-Simons, que e uma teoria quântica de campos topológica em três dimensões, e usando-se o mapeamento de Seiberg-Witter com a solução em (2+1)-dimensões. A presença de divergências na teoria quântica de campos leva a considerar a possibilidade de modificar o princípio da incerteza de Heisemberg, introduzindo uma escala de comprimento fundamental, e esta modificação geram correções nas propriedades termodinâmica de buracos negros. Um dos efeitos associados as soluções tipo buraco negro, independente da dimensão do espaço-tempo, e a emissão térmica (Radiação Hawking), a qual e vista como um processo de tunelamento devido as flutuações do vácuo que acontece na região próxima ao horizonte de eventos. Neste trabalho, com o objetivo de investigar as correções devido a não comutatividade e ao princípio da incerteza generalizado, consideramos a métrica BTZ não-comutativa. Para tanto, usamos o formalismo de tunelamento via método de Hamilton-Jacobi. / The general relativity theory predicts black hole type solutions, which are characterized by the existence of an event horizon. As an example, the metric obtained by Ba~nados- Teitelboim-Zanelli (BTZ), which is a soluton of the gravitation in (2 + 1)-dimensions in what is considered a negative cosmological constant. In recent years, noncommutative black holes have been investigated by many authors in the literature. In particular, the BTZ metric non-commutative was obtained considering the equivalent, which exists in three dimensions, between gravitation and Chern-Simons theory, which is a quantum theory topological elds in three dimensions, and using it mapping Seiberg-Witter with the solution of (2 + 1)-dimensions. The presence of divergences in quantum eld theory leads to consider the possibility of modifying the principle of Heisenberg uncertainty by introducing a fundamental length scale, and this modi cation generate corrections to the thermodynamic properties of black holes. One of the e ects associated with the black hole type solutions, regardless of the space-time dimension is the thermal emission (Hawking radiation), which is seen as a process of tunneling due to vacuum uctuations that happens in the region near the event horizon . In this work, in order to investigate the corrections due to noncommutativity and the principle of widespread uncertainty, we consider the metric BTZ noncommutative. For this, we use tunneling formalism via Hamilton-Jacobi method.
369

Incertezas e impactos de mudanças climáticas sobre o regime de vazões na Bacia Hidrográfica do Rio Uruguai

Adam, Katiúcia Nascimento January 2016 (has links)
Mudanças climáticas podem afetar a distribuição espacial e temporal das variáveis hidrológicas, tendo como consequências alterações nos regimes de precipitação e vazão dos rios. Aumentos ou reduções no volume de escoamento de uma bacia hidrográfica podem, por exemplo, produzir danos aos ecossistemas, afetar a produção de alimentos, abastecimento de água, navegação e geração de energia. Atualmente buscam-se relações que permitam entender os processos de mudanças climáticas a fim avaliar os impactos e mitigá-los, assim como avaliar as incertezas inerentes ao processo de modelagem hidrológica de tais mudanças. Neste contexto este trabalho apresenta uma metodologia de quantificação e análise de incertezas para estudos de mudanças climáticas, tomando como estudo de caso a bacia hidrográfica do Rio Uruguai (BHRU) com área aproximada de 110,000 Km². Para tanto três fontes de incerteza foram analisadas e comparadas: o modelo hidrológico, técnicas de remoção de viés e modelos climáticos. O modelo hidrológico MGB-IPH foi avaliado quanto ao processo de parametrização, utilizando diferentes períodos de simulação para calibração: (i) Período de calibração 1 – MGB/P1: representando a série completa de observações de 1960-1990 com verificação no período de 1992-1999; (ii) Período de calibração 2 - MGB/P2: calibração em período seco e verificação de período de cheias (iii) Período de calibração 3 – MGB/P3: calibração em período característico de cheias e verificação de período de estiagem. Três diferentes técnicas de remoção de viés foram aplicadas para analisar o grau de incerteza que a escolha de um determinado método de correção pode agregar ao resultado final: (i) RV1 - Técnica de Mapeamento Quantil-Quantil; (ii) RV2 - Técnica de Escalonamento Linear e (iii) RV3 - Técnica Delta change. Os modelos climáticos globais (GMC’s) foram analisados quanto a sua estrutura, comparando projeções de cinco diferentes modelos: MPEH5 (ECHAM5/MPIOM), GFCM21 (GFDL-CM2.1), MRCGCM (MRI-CGCM2.3.2), HADCM3 (UKMO-HadCM3) e NCCCSM (CCSM3). Adicionalmente, também foram analisadas as projeções climáticas de cinco diferentes versões do modelo climático regional (RCM) ETA/CPTEC: CT20, CT40, LOW, MID e HIGH. Inicialmente os resultados das simulações provenientes de cada uma destas fontes foram comparados de maneira isolada e em seguida de maneira combinada. Portanto, a metodologia foi dividida em Etapa (1) e Etapa (2). A Etapa (1) teve por objetivo responder a seguinte pergunta: Qual dentre as fontes de incerteza selecionadas agrega maior variação ao resultado final? Ou seja, qual destas fontes propaga maior incerteza em termos de impactos de mudanças climáticas na BHRU? Os resultados obtidos por cada uma das fontes de incerteza foram comparados em termos de anomalias de vazões médias de longo período (QMLP), máximas e mínimas anuais. Na Etapa (2) foi realizada a análise total de incerteza, ou seja, a análise combinada dos resultados obtidos na Etapa (1). As anomalias de vazões foram apresentadas utilizando as curvas de distribuição acumulada (CDF’s) e a incerteza total expressa pela diferença entre os percentis 5% e 95%. Considerando os resultados obtidos para as vazões médias de longo período (QMLP), as fontes podem ser ordenadas de forma decrescente, em relção ao grau de incerteza que propagam: modelos climáticos globais > modelos climáticos regionais > técnicas de remoção de viés > modelo hidrológico. Para as vazões extremas os RCM’s apresentam as maiores variações de anomalias se comparadas às dos modelos hidrológicos e técnicas de remoção de viés, inclusive para ambos os extremos, máximos e mínimos. Esta variação se dá principalmente, pelos resultados de LOW e MID. Estas informações podem ajudar os gestores e tomadores de decisão no adequado gerenciamento e planejamento dos recursos hídricos sob condições de mudanças climáticas, assim como o entendimento da incerteza associada. / Climate change can affect the spatial and temporal distribution of hydrological variables, with the consequences of changes in precipitation regimes and river flows. Increase or decrease the flow of rivers, for example, can cause damage to ecosystems, affecting food production, water supply, navigation and power generation. Currently seeking to relationships that allow understand climate change processes in order to assess the impacts and mitigate them, and assess the uncertainties inherent in hydrologic modeling process of such climate change. This thesis aimed at the development of a methodology for quantification and analysis of uncertainties for climate change studies in hydrology , taking as a case study the basin of the Uruguay River (BHRU) with a drainage area near 110,000 km². For that three sources of uncertainty were analyzed and compared: the hydrologic model, bias removal techniques and climate models. The hydrological model MGB-IPH was evaluated for parameterization, using different simulation periods for calibration: (i) MGB /P1: full range with calibration period (1960-1990) and validate (1992-1999); (ii) MGB / P2: calibrated in the period of dry and validated in the flood season (iii) MGB/P3: calibrated in the period of floods and validated in the dry season. Three different bias correction methods were applied to analyze the degree of uncertainty that the choice of a particular method of correction can add to the final result: (i) RV1 - Quantil-Quantil Mapping; (ii) RV2 - Linear Scaling, and (iii) RV3 - Delta Change Technique. Global climate models (GMC's) were analyzed for their structure, comparing projections of five different models: MPEH5 (ECHAM5/MPI-OM), GFCM21 (GFDLCM2.1), MRCGCM (MRI-CGCM2.3.2), HADCM3 (UKMO-HadCM3) e NCCCSM (CCSM3). Additionaly, climate projections from five different versions of the regional climate model (RCM) ETA / CPTEC were also analyzed: CT20, CT40, LOW, MID e HIGH. Initially the simulation results from each of the sources of uncertainty were compared individually (single propagation) and then in a combined way (multi propagation). Therefore, the methodology was divided in Step (1) and Step (2). Step (1) aimed to answer: Which of the selected sources of uncertainty adds more variation to the final result? Which of these sources propagates greater uncertainty in terms of impacts of climate change on BHRU? The results for each of the sources of uncertainty were compared in terms of long-term mean flow (QMLP), maximum and minimum annual flow. In Step (2) total uncertainty analysis was performed, therefore the combined analysis of the results obtained in Step (1). The anomalies in discharge were presented using the cumulative distribution function (CDF's) and the total uncertainty expressed by the difference between the percentiles 5% and 95%. Throughout the application of the proposed methodology it was concluded that: (i) for the extremes (maximum and minimum) annual discharges the largest source of uncertainty are the projections of the RCM's, followed by the the bias removal technique and finally the hydrological model; (ii) for the QMLP the largest source of uncertainty are followed global climate models, then the regional climate models. This information can help managers and decision makers in the proper management and planning of water resources under climate change conditions, as well as the understanding of the associated uncertainty.
370

Família: peça fundamental na ressocialização de adolescentes em conflito com a lei?

Fernanda Valéria Gomes dos Santos 13 April 2007 (has links)
Adolescentes em conflito com a lei e a vulnerabilidade social das suas famílias têm sido amplamente discutidos no cenário acadêmico, político e social. Também, tem se tornado comum, em debates, o exacerbado envolvimento de adolescentes com práticas infracionais, a visão estigmatizada da sociedade sobre os adolescentes e o aumento vertiginoso do número de reincidências. Diante dessa realidade, este estudo se propõe trabalhar as questões pertinentes à ressocialização do adolescente em conflito com a lei, e teve por objetivo: compreender a contribuição da dinâmica familiar no processo de ressocialização e na manutenção desse processo em adolescentes que cometeram atos infracionais. Os participantes da pesquisa foram constituídos por dois grupos. Dez profissionais, entre eles psicólogos, orientadores sociais, assistente social e pedagogo, que trabalham na medida de Liberdade Assistida. E dez famílias de adolescentes que haviam recebido progressão de medida para a Liberdade Assistida. Os instrumentos para a coleta de dados foram compostos de uma entrevista semidirigida e de um questionário criado pela pesquisadora a partir dos objetivos da pesquisa. A metodologia é de natureza qualitativa, tendo em vista que esta permite a descrição de fenômenos em um contexto. As análises dos dados mostraram que as várias facetas da ressocialização de adolescentes em conflito com a lei são vivenciadas numa realidade permeada pela precariedade, não só econômica, mas também de vínculos, calcados na violência, na provisoriedade e na instabilidade, perpassados por aspectos psicossociais como estigmatização e culpabilização. Diante desses aspectos, parece que a revolta da família constitui expressão de demonstrar inconformidade diante das condições de existência e de tratamentos recebidos. A coexistência desses fatores, dentre outros, acrescidos da dificuldade dos familiares em lidar com seus filhos, o uso de substâncias psicoativas e o envolvimento com amigos que exercem influência perniciosa, parecem favorecer a permanência do adolescente no mundo delituoso. Porém, quando os familiares apóiam efetivamente os seus filhos em condutas socialmente aceitas educando-os, estes expressam o desejo de mudança, retomando aos estudos e afastando-se de amigos que possam contribuir para o retorno à prática infracional, investindo inclusive, em curso profissionalizante. / Teenagers in conflict with, before law, and their families social vulnerability have been largelly discussion matter in academic, political and social scenery. It has also become usual debating teenagers aggravating envolvement in infringing pratices, societys stigmatizing view on about teenagers and recurrences vertiginous number increase. In front of before this reality, this study accademic wok aims at treating working questions that are pertinent to teenager in conflict ressocialization ant it his work is meant undertansing comprehensing domestic dynamic contribution in the resocialization process and in this process aintenance support in teenagers who have commited perpretateb inflictng acts. This research participants consited of two groups: on one side, ten profissionals among psychologists, social advisers, guiderd social assistants attendants and pedagogues that work act in assted freedom measure and teenagers families that had received assisted freedom measure progression. The tools data collection have been compounded by semdirected interview and with a questionaire, elaborated by this researcher, from this investigation objetives. Methodology nature is a a qualitative one, considering that this kind of methodology permits, allows a contextual phenomenons description. The data analyses denoted that teenagers in conflict with law resocialization several facets are vitalized in a certain reality that is permeat by precariousness not only in economic field, but also with regard to bonds trodden on the violence, on the precariousness and on the instability that are flitted by psychosocial aspects such as stimatization and guiltness culpabilization. In front of these aspects, it seems that familys revolt constitutes inconformity demonstration expression, in front of their existence condtions and received treataments these factores cohexistence, among other-ones in creased of family, domestic peolpe difficulty in dealing with their childrensons and daughters in dealing with psychoactive substances and involvement with friends that exercive pernicous influence upon them see to support, to strenghten teenagers maintenance in the transgressive world. When family members, however, give support, uphold, effectively, their children yuong sons and daughters on well accepted behaviours well breeding, edcating them, these demostrate changing wish retaking their studies including professional, vocational couses, and swerving themselves from these friends group tho could contribute returnig to transgressive practices.

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