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Eng, Stefan. "Heuristisk profilbaserad optimering av instruktionscache i en online Just-In-Time kompilator." Thesis, Linköping University, Department of Computer and Information Science, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2452.
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This master’s thesis examines the possibility to heuristically optimise instruction cache performance in a Just-In-Time (JIT) compiler.
Programs that do not fit inside the cache all at once may suffer from cache misses as a result of frequently executed code segments competing for the same cache lines. A new heuristic algorithm LHCPA was created to place frequently executed code segments to avoid cache conflicts between them, reducing the overall cache misses and reducing the performance bottlenecks. Set-associative caches are taken into consideration and not only direct mapped caches.
In Ahead-Of-Time compilers (AOT), the problem with frequent cache misses is often avoided by using call graphs derived from profiling and more or less complex algorithms to estimate the performance for different placements approaches. This often results in heavy computation during compilation which is not accepted in a JIT compiler.
A case study is presented on an Alpha processor and an at Ericsson developed JIT Compiler. The results of the case study shows that cache performance can be improved using this technique but also that a lot of other factors influence the result of the cache performance. Such examples are whether the cache is set-associative or not; and especially the size of the cache highly influence the cache performance.
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Vragović, Igor. "Frenkel exciton model of excitation and recombination processes in crystalline [alpha]-PTCDA [Alpha-PTCDA]." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10873132.
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Gomez, Luz Marina Gomez. "Regressão não paramétrica com processos estacionários alpha-mixing via ondaletas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-19062013-153433/.
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Nesta tese consideramos um modelo de regressão não paramétrica, quando a variável explicativa e um processo estritamente estacionário e alpha-mixing. São estudadas as condições sobre o processo Xt e sua estrutura de dependência, assim como do domínio da função f a ser estimada. Também são feitas as adaptações necessárias aos procedimentos para obter as taxas de convergência do risco para a norma Lp, no caso de ondaletas deformadas. Em relação às ondaletas adaptativas de Haar, obtêm-se as taxas de convergência do risco do estimador proposto. Mediante estudos de simulação, e avaliado o desempenho dos procedimentos propostos quando aplicados a amostras finitas sob diferentes níveis de perturbação do sinal e diferentes tamanhos da amostra. Também são feitas aplicações a dados reais.In this thesis we consider a nonparametric regression model, when the exploratory variables are alpha-mixing stationary processes. We obtain convergence rates for risk for Lp norm, via warped wavelets, under suitable regularity conditions. For estimation using design adapted Haar wavelets we obtain convergence rates for the risk of the proposed estimator. The performance of the estimators are assessed via simulation studies with dierent sample sizes and dierent signal-to-noise ratios. Applications to real data are also given.
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Perry, Reginald Jon. "An analysis of alpha-particle-induced soft errors in high-density dynamic random-access memory arrays." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/13535.
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Silva, Francyelle de Lima e. "Estimação de cópulas via ondaletas." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-03122014-214943/.
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Cópulas tem se tornado uma importante ferramenta para descrever e analisar a estrutura de dependência entre variáveis aleatórias e processos estocásticos. Recentemente, surgiram alguns métodos de estimação não paramétricos, utilizando kernels e ondaletas. Neste contexto, sabendo que cópulas podem ser escritas como expansão em ondaletas, foi proposto um estimador não paramétrico via ondaletas para a função cópula para dados independentes e de séries temporais, considerando processos alfa-mixing. Este estimador tem como característica principal estimar diretamente a função cópula, sem fazer suposição alguma sobre a distribuição dos dados e sem ajustes prévios de modelos ARMA - GARCH, como é feito em ajuste paramétrico para cópulas. Foram calculadas taxas de convergência para o estimador proposto em ambos os casos, mostrando sua consistência. Foram feitos também alguns estudos de simulação, além de aplicações a dados reais.Copulas are important tools for describing the dependence structure between random variables and stochastic processes. Recently some nonparametric estimation procedures have appeared, using kernels and wavelets. In this context, knowing that a copula function can be expanded in a wavelet basis, we have proposed a nonparametric copula estimation procedure through wavelets for independent data and times series under alpha-mixing condition. The main feature of this estimator is the copula function estimation without assumptions about the data distribution and without ARMA - GARCH modeling, like in parametric copula estimation. Convergence rates for the estimator were computed, showing the estimator consistency. Some simulation studies were made, as well as analysis of real data sets.
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Gonçalves, Vander. "O processo de mudança na instituição Alpha nos últimos 10 anos." Florianópolis, SC, 2002. http://repositorio.ufsc.br/xmlui/handle/123456789/84027.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.Made available in DSpace on 2012-10-20T05:36:57Z (GMT). No. of bitstreams: 1 193481.pdf: 1407859 bytes, checksum: 8c056d29ca85b0afd364c090662031ee (MD5)
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Fries, Sébastien. "Anticipative alpha-stable linear processes for time series analysis : conditional dynamics and estimation." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLG005/document.
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Dans le contexte des séries temporelles linéaires, on étudie les processus strictement stationnaires dits anticipatifs dépendant potentiellement de tous les termes d'une suite d'erreurs alpha-stables indépendantes et identiquement distribuées.On considère en premier lieu les processus autoregressifs (AR) et l'on montre que des moments conditionnels d'ordres plus élevés que les moments marginaux existent dès lors que le polynôme caractéristique admet au moins une racine à l'intérieur du cercle unité.Des formules fermées sont obtenues pour les moments d'ordre un et deux dans des cas particuliers.On montre que la méthode des moindres carrés permet d'estimer une représentation all-pass causale du processus dont la validité peut être vérifiée par un test de type portmanteau, et l'on propose une méthode fondée sur des propriétés d'extreme clustering pour retrouver la représentation AR originale.L'AR(1) stable anticipatif est étudié en détails dans le cadre des vecteurs stables bivariés et des formes fonctionnelles pour les quatre premiers moments conditionnels sont obtenues pour toute paramétrisation admissible.Lors des évènements extrêmes, il est montré que ces moments deviennent équivalents à ceux d'une distribution de Bernoulli chargeant deux évolutions futures opposées: accroissement exponentiel ou retour aux valeurs centrales.Des résultats parallèles sont obtenus pour l'analogue de l'AR(1) en temps continu, le processus d'Ornstein-Uhlenbeck stable anticipatif.Pour des moyennes mobiles alpha-stables infinies, la distribution conditionnelle des chemins futurs sachant la trajectoire passée est obtenue lors des évènements extrêmes par le biais d'une nouvelle représentation des vecteurs stables multivariés sur des cylindres unités relatifs à des semi-normes.Contrairement aux normes, ce type de représentation donne lieu à une propriété de variations régulières des queues de distribution utilisable dans un contexte de prévision, mais tout vecteur stable n'admet pas une telle représentation. Une caractérisation est donnée et l'on montre qu'un chemin fini de moyenne mobile alpha-stable sera représentable pourvu que le processus soit "suffisamment anticipatif".L'approche s'étend aux processus résultant de la combinaison linéaire de moyennes mobiles alpha-stables, et la distribution conditionnelle des chemins futurs s'interprète naturellement en termes de reconnaissance de formesIn the framework of linear time series analysis, we study a class of so-called anticipative strictly stationary processes potentially depending on all the terms of an independent and identically distributed alpha-stable errors sequence.Focusing first on autoregressive (AR) processes, it is shown that higher order conditional moments than marginal ones exist provided the characteristic polynomials admits at least one root inside the unit circle. The forms of the first and second order moments are obtained in special cases.The least squares method is shown to provide a consistent estimator of an all-pass causal representation of the process, the validity of which can be tested by a portmanteau-type test. A method based on extreme residuals clustering is proposed to determine the original AR representation.The anticipative stable AR(1) is studied in details in the framework of bivariate alpha-stable random vectors and the functional forms of its first four conditional moments are obtained under any admissible parameterisation.It is shown that during extreme events, these moments become equivalent to those of a two-point distribution charging two polarly-opposite future paths: exponential growth or collapse.Parallel results are obtained for the continuous time counterpart of the AR(1), the anticipative stable Ornstein-Uhlenbeck process.For infinite alpha-stable moving averages, the conditional distribution of future paths given the observed past trajectory during extreme events is derived on the basis of a new representation of stable random vectors on unit cylinders relative to semi-norms.Contrary to the case of norms, such representation yield a multivariate regularly varying tails property appropriate for prediction purposes, but not all stable vectors admit such a representation.A characterisation is provided and it is shown that finite length paths of a stable moving average admit such representation provided the process is "anticipative enough".Processes resulting from the linear combination of stable moving averages are encompassed, and the conditional distribution has a natural interpretation in terms of pattern identification
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Dixit, Vikas. "Grain-Boundary Parameters Controlled Allotriomorphic Phase Transformations in Beta-Processed Titanium Alloys." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1357240292.
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Maunoury, Franck. "Conditions d'existence des processus déterminantaux et permanentaux." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC028/document.
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Nous établissons des conditions nécessaires et suffisantes d’existence et d’infinie divisibilité pour des processus ponctuels alpha-déterminantaux et, lorsque alpha est positif, pour leur intensité sous-jacente (en tant que processus de Cox). Dans le cas où l’espace est fini, ces distributions correspondent à des lois binomiales, négatives binomiales et gamma multidimensionnelles. Nous étudions de façon approfondie ces deux derniers cas avec un noyau non nécessairement symétriqueWe establish necessary and sufficient conditions for the existence and infinite divisibility of alpha-determinantal processes and, when alpha is positive, of their underlying intensity (as Cox process). When the space is finite, these distributions correspond to multidimensional binomial, negative binomial and gamma distributions. We make an in-depth study of these last two cases with a non necessarily symmetric kernel
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Wang, Qingfeng. "Rough path properties for local time of symmetric alpha stable processes." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/11052.
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Azzaoui, Nourddine. "Analyse et Estimations Spectrales des Processus alpha-Stables non-Stationnaires." Phd thesis, Université de Bourgogne, 2006. http://tel.archives-ouvertes.fr/tel-00138027.
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Dans cette thèse une nouvelle représentation spectrale des processus symétriques alpha-stables est introduite. Elle est basée sur une propriété de pseudo-additivité de la covariation et l'intégrale au sens de Morse-Transue par rapport à une bimesure que nous construisons en utilisant la pseudo-additivité. L'intérêt de cette représentation est qu'elle est semblable à celle de la covariance des processus du second ordre; elle généralise celle établie pour les intégrales stochastiques par rapport à un processus symétrique alpha-stable à accroissements indépendants. Une classification des processus harmonisables non stationnaires a été étudiée selon la structure de la bimesure qui les caractérise et les processus périodiquement covariés ont été définis. Pour pouvoir simuler cette inhabituelle classe de processus, une nouvelle décomposition en séries de type Lepage a été apportée. Finalement des techniques non paramétriques d'estimation spectrale sont discutées. En particulier un estimateur presque sûrement convergeant sous une condition de mélange fort, a été introduit pour les processus périodiquement covariés.
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Higgins, Jonathan. "Lyman-alpha scattering in the intergalactic medium during the epoch of reionisation." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/8805.
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We examine resonant scattering of Lyα (Lyman-alpha) photons in the neutral hydrogen Intergalactic Medium (IGM) at high redshift. Lyα scattering plays a key role in the 21cm emission/absorption against the Cosmic Microwave Background via the 'Wouthuysen-Field Effect' Knowledge of the strength of Lyα scattering induced by the first sources will constitute a significant step in predicting and understanding the eventual observations of the impact of these objects on the signal from the IGM during the Epoch of Reionisation (EoR), using planned facilities such as the Square Kilometre Array. A quantitative analysis of the scattering rate requires formulation and solution of the radiative transfer equation for the system. We consider radiative transfer of Lyα scattering far from a source in the homogeneous expanding IGM for photons that free stream until scattering in the blue wing of the local line profile: we describe an approximation that ignores spatial diffusion of photons and assumes a locally homogeneous scattering medium, allowing the calculation of simple analytic solutions to examine the dependence of the local scattering rate on various physical effects such as local expansion/contraction, and extend our approach to determine time-dependent solutions. The more complex problem of Lyα photons scattering in both frequency and space within a spherically symmetric medium is subsequently solved for several test problems using both Monte Carlo methods and a method based on the ray and moment radiative transfer equations following an approach due to Mihalas et al. [1975, 1976]. We examine local Lyα scattering around a continuum source in the homogeneous expanding IGM using both methods and compare our results with an analytic solution in the zero-temperature diffusion regime derived from an analogous solution for a monochromatic source found by Loeb and Rybicki [1999]. Our results are used to make estimates of the resulting size of the spherical region around the source that is rendered detectable via 21cm observations against the CMB background. We also examine cases with different density and velocity profiles and determine the effect on the scattering rate.
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Vragovic, Igor. "Frenkel exciton model of excitation and recombination processes in crystalline alpha-PTCDA." Doctoral thesis, Universitätsbibliothek Chemnitz, 2003. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200301370.
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Fuer anorganische Kristalle werden die chemischen Bindungen durch kovalente oder ionische
Beitraege dominiert. Im Gegensatz dazu stehen organische Molekuelkristalle, in denen in
jedem der Molekuele starke kovalente Bindungen vorherrschen, waehrend die Molekuele
untereinander nur relativ schwache Wechselwirkung zeigen. Daher sind die Veraenderungen
zwischen den Spektren freier Molekuele und den entsprechenden Kristallen wesentlich
geringer als die zwischen einem freien Atom und einem anorganischen Kristall.
In einem organischen Kristall kann eine optisch erzeugte elektronische Anregung zwischen
verschiedenen Molekuelen transferiert werden. Fuer das Modellsystem PTCDA
(3,4,9,10-Perylentetracarbonsaeuredianhydrid) wurden die elektronischen und vibronischen
Spektren analysiert und die aus dem Transfer der Anregung resultierende exzitonische
Bandstruktur untersucht. Die optische Absorption erzeugt ein Frenkel-Exziton am
Dispersionsmaximum in der Naehe des Gamma-Punktes in der Brillouin-Zone. Durch
inelastische Streuvorgaenge relaxiert dieses Exziton zum Dispersionsminimum am Rand
der Brillouin-Zone. Die Photolumineszenz bei tiefen Temperaturen entsteht daraus durch
vertikale Rekombination, wobei der Endzustand eine vibronische Anregung mit endlichem
Quasi-Impuls enthaelt. Die berechnete strahlende Rekombinationsrate und die Linienform
der Photolumineszenzbande stimmen dabei gut mit den experimentellen Ergebnissen ueberein.
Das Modell des Exzitonentransfers im Volumenmaterial kann auf Filme
endlicher Dicke verallgemeinert werden, so dass sich die
veraenderten optischen Eigenschaften duenner Filme beschreiben
lassen. Durch die endliche Zahl der molekularen Monolagen in einem
solchen Film ist das energetische Spektrum diskret, wobei die
Einhuellenden der exzitonischen Wellenfunktionen entlang der
Quantisierungsrichtung an die Zustaende in einem Quantentrog mit
unendlich hohen Barrieren erinnern.
Das Zusammenspiel von geometrischer Randbedingung und energetischer
Lage des molekularen uebergangs in der Randschicht kann sowohl
zu einer Rot- als auch zu einer Blauverschiebung der optischen Antwort
fuehren.
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Hemperly, Susan Barbara. "Mechanistic studies of diastereoselective cyclopropanations of homochiral ene-ketals and synthesis and resolution of diastereomeric alpha-hydroxycycloalkanone ketals." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184886.
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A series of homochiral ene ketals were prepared and subjected to the Simmons-Smith cyclopropanation. A mechanistic model was formulated to explain the observed diastereoselectivity seen for the common ring systems. Diastereoselectivity is thought to result from preferential chelation of the Simmons-Smith reagent at the least sterically hindered lone pair of electrons on the dioxolane oxygen proximal to the alkene. The role of dioxolane oxygen was inferred from studies with a hydrocarbon model system. The effect of cyclohexene ring conformation on the diastereoselectivity was examined for conformationally restricted ene ketal systems. Reagent chelation by the pseudoequatorial dioxolane oxygen atom was shown to be favored. This preference can either antagonize or reinforce diastereoselectivity due to steric hindrance of the dioxolane oxygen atoms from dissymmetric placement of the appendages on the dioxolane ring. A general method for the chromatographic resolution of diastereomeric α-hydroxycycloalkanone ketals derived from 1,4-di-O-benzyl-L-threitol is reported. Separability is thought to result from differences in intramolecular hydrogen bonding for the two diastereomeric forms.
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Blauth, Jérôme [Verfasser]. "Infinite rate mutually catalytic branching driven by alpha-stable Lévy processes / Jérôme Blauth." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1125910283/34.
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Kirzow, Robert, and Colleen Sweeney. "An exploratory study of Alpha contracting: antecedents, processes, issues, success factors and consequences." Monterey, California. Naval Postgraduate School, 2009. http://hdl.handle.net/10945/10471.
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Approved for public release, distribution unlimitedJoint Applied Project
Alpha contracting is a collaborative effort between a buyer and supplier during contract formation to maximize efficiency and effectiveness. Although several benefits of Alpha contracting are espoused in the literature, the concept is not ubiquitous, nor is it well understood. The purpose of this Joint Applied Project is to evaluate current Department of Defense (DoD) procedures for the use of Alpha contracting. Specifically, we plan to explore Alpha contracting to define what constitutes successful/unsuccessful Alpha contracting, as well as the contributing factors to both outcomes. Additionally, we will identify antecedents for and consequences of use, and variations of the processes employed. This research will identify the utility of Alpha contracting, and explain its narrow usage to date. Using a case study methodology, we will interview experienced Alpha contracting teams, to include contracting officers, DCAA, DCMA, end users/customers, program managers and acquisition directors to better understand the Alpha contracting phenomenon. We will use interview results and research to develop recommendations to address the factors that lead to successful Alpha contracting, as well as the barriers that arise once used.
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Kirzow, Robert Sweeney Colleen. "An exploratory study of Alpha contracting antecedents, processes, issues, success factors and consequences /." Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/JAP/2009/Sep/09Sep%5FKirzow%5FJAP.pdf.
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"Submitted in partial fulfillment of the requirements for the degree of Master of Contract Management from the Naval Postgraduate School, September 2009."Advisor(s): Cuskey, Jeffrey ; Hawkins, Timothy. "September 2009." "Joint applied project"--Cover. Description based on title screen as viewed on 6 November 2009. Author(s) subject terms: Alpha contracting. Includes bibliographical references (p. 115-117). Also available in print.
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Hu, Bin. "Vesicle adhesion via interaction of integrin [alpha]IIb[beta]3 [alpha IIb beta 3] and cyclic-RGD-lipopeptide a model of cell adhesion processes /." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962127124.
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Souza, Wagner Barreto de. "Passeios aleatórios estáveis em Z com taxas não-homogêneas e os processos quase-estáveis." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-19022013-151640/.
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Seja $\\mathcal X=\\{\\mathcal X_t:\\, t\\geq0,\\, \\mathcal X_0=0\\}$ um passeio aleatório $\\beta$-estável em $\\mathbb Z$ com média zero e com taxas de saltos não-homogêneas $\\{\\tau_i^: i\\in\\mathbb Z\\}$, com $\\beta\\in(1,2]$ e $\\{\\tau_i: i\\in\\mathbb Z\\}$ sendo uma família de variáveis aleatórias independentes com distribuição marginal comum na bacia de atração de uma lei $\\alpha$-estável, com $\\alpha\\in(0,2]$. Nesta tese, obtemos resultados sobre o comportamento do processo $\\mathcal X_t$ para tempos longos, em particular, obtemos seu limite de escala. Quando $\\alpha\\in(0,1)$, o limite de escala é um processo $\\beta$-estável mudado de tempo pela inversa de um outro processo, o qual envolve o tempo local do processo $\\beta$-estável e um independente subordinador $\\alpha$-estável; chamamos o processo resultante de processo quase-estável. Para o caso $\\alpha\\in[1,2]$, o limite de escala é um ordinário processo $\\beta$-estável. Para $\\beta=2$ e $\\alpha\\in(0,1)$, o limite de escala é uma quase-difusão com medida de velocidade aleatória estudada por Fontes, Isopi e Newman (2002). Outros resultados sobre o comportamento de $\\mathcal X$ para tempos longos são envelhecimento e localização. Nós obtemos resultados de envelhecimento integrado e não-integrado para $\\mathcal X$ quando $\\alpha\\in(0,1)$. Relacionado à esses resultados, e possivelmente de interesse independente, consideramos o processo de armadilha definido por $\\{\\tau_{\\mathcal X_t}: t\\geq0\\}$, e obtemos seu limite de escala. Concluímos a tese com resultados sobre localização de $\\mathcal X$. Mostramos que ele pode ser localizado quando $\\alpha\\in(0,1)$, e que não pode ser localizado quando $\\alpha\\in(1,2]$, assim estendendo os resultados de Fontes, Isopi e Newman (1999) para o caso de passeios simples simétricos.Let $\\mathcal X=\\{\\mathcal X_t:\\, t\\geq0,\\, \\mathcal X_0=0\\}$ be a mean zero $\\beta$-stable random walk on $\\mathbb Z$ with inhomogeneous jump rates $\\{\\tau_i^: i\\in\\mathbb Z\\}$, with $\\beta\\in(1,2]$ and $\\{\\tau_i: i\\in\\mathbb Z\\}$ is a family of independent random variables with common marginal distribution in the basin of attraction of an $\\alpha$-stable law with $\\alpha\\in(0,2]$. In this thesis we derive results about the long time behavior of this process, in particular its scaling limit. When $\\alpha\\in(0,1)$, the scaling limit is a $\\beta$-stable process time-changed by the inverse of another process, involving the local time of the $\\beta$-stable process and an independent $\\alpha$-stable subordinator; the resulting process may be called a quasistable process. For the case $\\alpha\\in[1,2]$, the scaling limit is an ordinary $\\beta$-stable process. For $\\beta=2$ and $\\alpha\\in(0,1)$, the scaling limit is a quasidiffusion with random speed measure studied by Fontes, Isopi and Newman (2002). Other results about the long time behavior of $\\mathcal X$ concern aging and localization. We obtain integrated and non integrated aging results for $\\mathcal X$ when $\\alpha\\in(0,1)$. Related to these results, and possibly of independent interest, we consider the trap process defined as $\\{\\tau_{\\mathcal X_t}: t\\geq0\\}$, and derive its scaling limit. We conclude the thesis with results about localization of $\\mathcal X$. We show that it localizes when $\\alpha\\in(0,1)$, and does not localize when $\\alpha\\in(1,2]$, extending results of Fontes, Isopi and Newman (1999) for the simple symmetric case.
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Wesselhöfft, Niels. "Utilizing self-similar stochastic processes to model rare events in finance." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22360.
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In der Statistik und der Mathematik ist die Normalverteilung der am meisten verbreitete, stochastische Term für die Mehrheit der statistischen Modelle. Wir zeigen, dass der entsprechende stochastische Prozess, die Brownsche Bewegung, drei entscheidende empirische Beobachtungen nicht abbildet: schwere Ränder, Langzeitabhängigkeiten und Skalierungsgesetze.
Ein selbstähnlicher Prozess, der in der Lage ist Langzeitabhängigkeiten zu modellieren, ist die Gebrochene Brownsche Bewegung, welche durch die Faltung der Inkremente im Limit nicht normalverteilt sein muss. Die Inkremente der Gebrochenen Brownschen Bewegung können durch einen Parameter H, dem Hurst Exponenten, Langzeitabhängigkeiten darstellt werden. Für die Gebrochene Brownsche Bewegung müssten die Skalierungs-(Hurst-) Exponenten über die Momente verschiedener Ordnung konstant sein. Empirisch beobachten wir variierende Hölder-Exponenten, die multifraktales Verhalten implizieren.
Wir erklären dieses multifraktale Verhalten durch die Änderung des alpha-stabilen Indizes der alpha-stabilen Verteilung, indem wir Filter für Saisonalitäten und Langzeitabhängigkeiten über verschiedene Zeitfrequenzen anwenden, startend bei 1-minütigen Hochfrequenzdaten. Durch die Anwendung eines Filters für die Langzeitabhängigkeit zeigen wir, dass die Residuen des stochastischen Prozesses geringer Zeitfrequenz (wöchentlich) durch die alpha-stabile Bewegung beschrieben werden können. Dies erlaubt es uns, den empirischen, hochfrequenten Datensatz auf die niederfrequente Zeitfrequenz zu skalieren. Die generierten wöchentlichen Daten aus der Frequenz-Reskalierungs-Methode (FRM) haben schwerere Ränder als der ursprüngliche, wöchentliche Prozess. Wir zeigen, dass eine Teilmenge des Datensatzes genügt, um aus Risikosicht bessere Vorhersagen für den gesamten Datensatz zu erzielen. Im Besonderen wäre die Frequenz-Reskalierungs-Methode (FRM) in der Lage gewesen, die seltenen Events der Finanzkrise 2008 zu modellieren.Coming from a sphere in statistics and mathematics in which the Normal distribution is the dominating underlying stochastic term for the majority of the models, we indicate that the relevant diffusion, the Brownian Motion, is not accounting for three crucial empirical observations for financial data: Heavy tails, long memory and scaling laws. A self-similar process, which is able to account for long-memory behavior is the Fractional Brownian Motion, which has a possible non-Gaussian limit under convolution of the increments. The increments of the Fractional Brownian Motion can exhibit long memory through a parameter H, the Hurst exponent. For the Fractional Brownian Motion this scaling (Hurst) exponent would be constant over different orders of moments, being unifractal. But empirically, we observe varying Hölder exponents, the continuum of Hurst exponents, which implies multifractal behavior. We explain the multifractal behavior through the changing alpha-stable indices from the alpha-stable distributions over sampling frequencies by applying filters for seasonality and time dependence (long memory) over different sampling frequencies, starting at high-frequencies up to one minute. By utilizing a filter for long memory we show, that the low-sampling frequency process, not containing the time dependence component, can be governed by the alpha-stable motion. Under the alpha-stable motion we propose a semiparametric method coined Frequency Rescaling Methodology (FRM), which allows to rescale the filtered high-frequency data set to the lower sampling frequency. The data sets for e.g. weekly data which we obtain by rescaling high-frequency data with the Frequency Rescaling Method (FRM) are more heavy tailed than we observe empirically. We show that using a subset of the whole data set suffices for the FRM to obtain a better forecast in terms of risk for the whole data set. Specifically, the FRM would have been able to account for tail events of the financial crisis 2008.
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Dias, Paulo Victor Sarmento. "Desenvolvimento de processo de produção e caracterização de interferon-α2a secretado no espaço periplásmico de Escherichia Coli." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-04122017-150200/.
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Os IFN-α2 são atualmente utilizados em terapia de hepatite B e C, leucemia, mieloma múltiplo, leucemia de células pilosas, melanoma, sarcoma de Kaposi, linfoma folicular e carcinoma de células renais, em associação ou não com outras drogas. Este trabalho descreve um processo de produção, purificação e caracterização de interferon-α2a secretado para o espaço periplasmico de E. coli utilizando um vetor baseado no uso constitutivo do promotor lambda PL. Foi validada também uma análise em cromatografia líquida de alta eficiência em fase reversa (RP-HPLC) para monitoração do processo. Dessa forma, este trabalho descreve inicialmente um método de RP-HPLC para análise qualitativa e quantitativa de interferon-α2a e interferon-α2b. O método foi desenvolvido e validado quanto à recuperação, precisão, linearidade, sensibilidade e especificidade. O teste de recuperação indicou erro menor que 1 % e as determinações quantitativas intra-dia e inter-dia apresentaram desvio padrão relativo sempre menores que 4 %, enquanto a sensibilidade experimental foi de 0,3 μg (RSD = 5 %). Em relação à linearidade, o coeficiente de correlação assumiu o valor de 0,998 (p<0,0001), para o intervalo de massa analisada de 0,62 a 10 μg de interferon. Essa metodologia permite a aplicação de RP-HPLC como uma ferramenta poderosa para monitoração de níveis de expressão e qualidade do interferon-α2 durante ou logo após a fermentação. A temperatura ótima de expressão foi avaliada nos intervalos de 30 a 42 °C, em cultivo em erlenmeyer. As produções volumétrica e específica foram maiores para temperaturas iguais ou superiores a 35 °C. Dessa forma, considerando a potencial degradação da proteína recombinante induzida pela temperatura, a temperatura ótima para a expressão de interferon neste processo foi definida como 35 °C. Os maiores valores de produção específica e volumétrica obtidos, em produção em erlenmeyer, foram 1,04 μg/mL/A600 e 3,45 mg/L, respectivamente. Foi padronizado um método de purificação laboratorial, em duas etapas: uma cromatografia de troca iônica, seguida de uma etapa de cromatografia de exclusão molecular. A pureza final e a recuperação em massa foram de, respectivamente, 95,3 % e 66 %. O produto final também foi caracterizado por meio de análise em SDS-PAGE, western blotting, espectrometria de massas, HPLC de exclusão molecular e HPLC em fase reversa.IFN-α2 is currently utilized in hepatitis B and C, leukemia, multiple myeloma, hairy cell leukemia, melanoma, Kaposi\'s sarcoma, follicular lymphoma, and renal cell carcinoma therapy, with or without other drugs. In this work, a process for E. coli periplasmic interferon-α2a production and purification utilizing a lambda PL promoter based on constitutive expression was proposed. As a tool for production monitoring, reversedphase high-performance liquid chromatography (RP-HPLC) analysis directly from periplasmic extract was validated. Thus, initially it was described a RP-HPLC methodology for qualitative and quantitative analysis of recombinant human interferon-α2a and interferon-α2b. The method has been set up and validated for accuracy, precision, linearity, sensitivity and specificity. A recovery test indicated a bias of less than 1% and intra-day and inter-day quantitative determinations presented relative standard deviations always < 4 %, while experimental sensitivity was 0.3 μg (RSD = 5 %). Regarding to linearity, the coefficient of determination was 0.998 (p<0.0001), for a range of analyzed interferon mass from 0,62 to 10 μg. This rapid methodology allows the application of the RP-HPLC as a powerful tool to monitor the production yield and quality of periplasmic Interferon α2 right after, or even during the fermentation. The optimum expression temperature was evaluated in flask cultures from 30 to 42 °C. It was observed that the volumetric and specific production were higher for culture temperatures equal or above 35 °C. Thus, considering the potential recombinant protein degradation induced by temperature, 35 °C was well-marked as the optimum temperature for interferon expression. The higher values for specific and volumetric production in culture flasks were 1.04 μg/mL/A600 and 3.45 mg/L respectively. As purification method, it was utilized ionic chromatography followed by size-exclusion chromatography. The final purity and mass recovery was, respectively, 95.3 % and 66 %. The final product was also characterized utilizing SDS-PAGE, western blotting, reversed-phase HPLC, size-exclusion HPLC and mass spectrometry analysis.
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SHIHOMATSU, HELENA M. "Aplicacao das tecnicas de diluicao isotopica por espectrometria de massa e alfa na determinacao de uranio e avaliacao da sua distribuicao em materiais geologicos." reponame:Repositório Institucional do IPEN, 1987. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9882.
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Dissertacao(Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Fontaine, Mathieu. "Processus alpha-stables pour le traitement du signal." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0037/document.
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En traitement du signal audio, le signal observé est souvent supposé être égal à la somme des signaux que nous souhaitons obtenir. Dans le cadre d'une modélisation probabiliste, il est alors primordial que les processus stochastiques préservent leur loi par sommation. Le processus le plus employé et vérifiant cette stabilité est le processus gaussien. Comparé aux autres processus α - stables vérifiant la même stabilité, les processus gaussiens ont la particularité d'admettre des outils statistiques facilement interprétables comme la moyenne et la covariance. L'existence de ces moments permet d'esquisser des méthodes statistiques en séparation des sources sonores (SSS) et plus généralement, en traitement du signal. La faiblesse de ces processus réside néanmoins dans l'incapacité à s'écarter trop loin de leurs moyennes. Cela limite la dynamique des signaux modélisables et peut provoquer des instabilités dans les méthodes d'inférence considérées. En dépit de non-existence d'une forme analytique des densités de probabilités, les processus α - stables jouissent de résultats non valables dans le cas gaussien. Par exemple, un vecteur α - stable non-gaussien admet une représentation spatiale unique. En résumé, le comportement d'une distribution multivariée α - stable est contrôlé par deux opérateurs. Une mesure dite «spectrale» informant sur l'énergie globale venant de chaque direction de l'espace et un vecteur localisant le centroïde de sa densité de probabilité. Ce mémoire de thèse introduit différents modèles α - stables d’un point de vue théorique et les développe dans plusieurs directions. Nous proposons notamment une extension de la théorie de filtrage α - stable monocanal au cas multicanal. En particulier, une nouvelle représentation spatiale pour les vecteurs α - stables est adoptée. Nous développons en outre un modèle de débruitage où le bruit et la parole découlent de distributions α - stables mais ayant un exposant caractéristique α différent. La valeur d' α permet de contrôler la stationnarité de chaque source. Grâce à ce modèle hybride, nous avons également déduit une explication rigoureuse sur des filtrages de Wiener heuristiques esquissés dans les années 80. Une autre partie de ce manuscrit décrit en outre comment la théorie α - stable permet de fournir une méthode pour la localisation de sources sonores. En pratique, elle nous permet d'en déduire si une source est active à un endroit précis de l'espaceIt is classic in signal processing to model the observed signal as the sum of desired signals. If we adopt a probabilistic model, it is preferable that law of the additive processes is stable by summation. The Gaussian process notoriously satisfies this condition. It admits useful statistical operators as the covariance and the mean. The existence of those moments allows to provide a statistical model for SSS. However, Gaussian process has difficulty to deviate from its mean. This drawback limits signal dynamics and may cause unstable inference methods. On the contrary, non-Gaussian α - stable processes are stable under addition, and permit the modeling of signals with considerable dynamics. For the last few decades, α -stable theory have raised mathematical challenges and have already been shown to be effective in filtering applications. This class of processes enjoys outstanding properties, not available in the Gaussian case. A major asset for signal processing is the unique spatial representation of a multivariate α - stable vector, controlled by a so-called spectral measure and a deterministic vector. The spectral measure provides information on the global energy coming from all space directions while the vector localizes the centroid of the probability density function. This thesis introduces several α -stables models, with the aim of extending them in several directions. First, we propose an extension of single-channel α - stable filtering theory to a multichannel one. In particular, a novel spatial representation for α - stable vectors is proposed. Secondly, we develop α - stable models for denoising where each component could admit a different α . This hybrid model provides a rigorous explanation of some heuristic Wiener filters outlined in the 1980s. We also describe how the α - stable theory yields a new method for audio source localization. We use the spectral measure resulting from the spatial representation of α - stable vectors. In practice, it leads to determine whether a source is active at a specific location. Our work consisted in investigating the α -stable theory for signal processing and developing several models for a wide range of applications. The models introduced in this thesis could also be extend to more signal processing tasks. We could use our mutivariate α - stable models to dereverberation or SSS. Moreover, the localization algorithm is implementable for room geometry estimation
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d'Estampes, Ludovic. "Traitement statistique des processus alpha-stables: mesures de dépendance et identification des ar stables. Test séquentiels tronqués." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2003. http://tel.archives-ouvertes.fr/tel-00005216.
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Dans ce travail, nous étudions de manière approfondie les lois $\al$-stables (lois à variance infinie). Dans le premier chapitre, nous rappelons les différentes propriétés des lois $\al$-stables univariées (stabilité, calcul des moments, simulation). Nous introduisons ensuite les lois symétriques $\al$-stables (\SaS) multivariées. Après avoir parlé de la mesure spectrale et de son intérêt pour caractériser l'indépendance, nous nous concentrons sur les mesures de dépendance. Constatant que le coefficient de covariation, largement utilisé actuellement, admet certaines limites, nous construisons dans le deuxième chapitre une nouvelle mesure de dépendance, appelée coefficient de covariation symétrique. Ce dernier nous permet, entre autres, de découvrir quelques spécificités des vecteurs \SaS. En effet, contrairement aux vecteurs gaussiens, on peut obtenir pour certains vecteurs \SaS\ à la fois une dépendance positive et une dépendance négative. Après avoir conclu le chapitre par l'étude de la loi asymptotique de l'estimateur du coefficient de covariation, nous abordons, dans le troisième chapitre, les processus autorégressifs à innovations stables. Nous présentons les différentes méthodes d'identification de l'ordre d'un processus AR: autocorrélation partielle (Brockwell et Davis) et statistiques quadratiques asymptotiquement invariantes basées sur les rangs (Garel et Hallin). De nombreuses simulations, effectuées en Matlab et Fortran, nous permettent de comparer ces méthodes et de constater l'importance du rôle joué par les statistiques de rang dans ce domaine. Pour finir, un problème de test séquentiel, développé dans le cadre d'un contrat industriel, nous permet d'introduire la notion de niveau de confiance après décision.
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Konda, Sreenivas. "FITTING MODELS OF NONSTATIONARY TIME SERIES: AN APPLICATION TO EEG DATA." online version, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1149265141.
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Gould, Ian C. "Electrophysiological indices of graded attentional and decision-making processes." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:e126089a-d87c-4ab4-aa4a-acf01988c7f2.
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In everyday life we regularly update our expectations about the locations at which sensory events may occur, and about the motor responses that are appropriate in a given situation. The experiments in this thesis investigated the neural correlates of perceptual processes and motor preparation during human decision making, and the regions that causally contribute to decision making in the human brain. In Chapter 3, I used electroencephalography (EEG) to investigate whether alpha-band (~8-14 Hz) oscillations provide a graded index of participants’ preparatory attentional states. Time-frequency analysis revealed that manipulating spatial certainty regarding the location of an upcoming visual target led to parametric changes in the lateralization of preparatory occipito-parietal alpha oscillations, and to parametric modulation of parieto-central beta-band (~15-25 Hz) power typically associated with response preparation. In Chapter 4, I used EEG to investigate whether evolution of lateralization of sensorimotor alpha- and beta-band activity reflected participants’ evolving expectations about an upcoming motor response. Lateralization of activity in both frequency bands varied parametrically with the available evidence, suggesting such lateralized activity correlates with participants’ internal decision variables. Further analysis identified unique contributions to lateralized and non-lateralized oscillatory activity due to the prior evidence, evidence update, and surprise related to the observed information at each stage of the task. In Chapter 5, I extended the paradigm developed in Chapter 4 for use with online repetitive transcranial magnetic stimulation (TMS) and concurrent EEG recording. Delivery of TMS during decision making allowed investigation of the causal role played by a left hemisphere medial intraparietal region that is the putative human homologue of the macaque medial intraparietal cortex (MIP). MIP stimulation disrupted decision-making behaviour by biasing participants’ decisions against contralateral-to-stimulation (i.e., right-handed) responses. Comparison of the magnitude of TMS-induced changes in behaviour and beta-band activity demonstrated that the intraparietal cortex plays a causal role both in decision making and in the appearance of beta-band activity over the motor cortex. In Chapter 6, the broader consequences of the experimental work presented in this thesis are discussed, in addition to promising directions for future research.
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Carter, Helen. "Uranium separations using extraction chromatography." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/11261.
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In the analysis of environmental samples for uranium and thorium pollutants and at natural levels for the dating of geological samples there was felt a need to develop better uranium and thorium separation procedures to replace the established anion exchange method used at AEA Technology plc. This was the first aim of the PhD research. Separation of uranium from thorium prior to measurement of the isotopes by alpha spectrometry was necessary due to the similar alpha energies of234U and 230Th. TRU and UTEVA extraction chromatography resins (EIChroM Industries) were investigated as potential replacements to the anion exchange separation method. The resins are claimed by EIChroM to offer the advantage of providing an actinide specific separation while reducing the separation time from 2 to 0.5 days; the volume of acidic waste produced by a factor of 3, therefore, the cost of analysis was reduced. A uranium and thorium separation procedure using the UTEVA extraction chromatography resin was developed. The uranium and thorium were sorbed by the UTEVA resin from 2M nitric acid. The thorium was then eluted from the resin with 5M hydrochloric acid and the uranium with 0.02M hydrochloric acid. The separation procedure was then evaluated using uraninite ore, coral, granite and lake sediment reference materials. The uranium and thorium concentrations and the 234U/238U and 23oTh/234U activity ratio values determined for the reference material were in good agreement with certified values. The presence of plutonium was found to interfere with the measurement of uranium and thorium by alpha spectrometry. This was due to the similar alpha energies of uranium, thorium and plutonium. The co-elution of plutonium with uranium and thorium from the UTEVA resin was prevented by the inclusion of a reduction step using iron (Il) sulphamate. The resulting plutonium (Ill) was not retained by the UTEVA column. The chemical recoveries for the procedure were similar to those for anion-exchange, but the extraction chromatography procedure provided a more rapid separation using less reagents.
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Loureiro, João Gustavo Pereira. "As funções do estradiol no processo da luteólise em bovinos: o estradiol estimula PGF2α através da ativação de receptores de P4 no endométrio?" Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-21082007-142157/.
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O estradiol (E2) exerce papel fundamental no desencadeamento da luteólise nos ruminantes. A redução das concentrações de E2 que se segue a ablação dos folículos retarda a luteólise enquanto que aplicações de E2 no final da fase luteínica estimulam a secreção de prostaglandina-F2α (PGF2α), induzindo a luteólise. O E2 pode preparar bioquimicamente o endométrio de forma que a progesterona (P4) possa estimular a secreção de PGF2α. Para esse trabalho foi utilizado um antagonista de P4 (RU486) no intuito de se estudar efeitos da P4 em associação com o E2 na produção de PGF2α. Foram conduzidos 2 experimentos com vacas holandesas em final da fase luteínica. No primeiro experimento, 2 grupos (n=4) receberam respectivamente RU486 (3mg/kg)+E2 (3mg) e placebo+E2. O uso do RU486 não inibiu a produção de PGFM (metabólito da PGF2α) e sim aumentou-a. O E2 estimulou a produção de PGFM. Verificou-se também que o etanol (ETOH) utilizado como solvente para o RU486 provocou forte pico de liberação de PGFM. No experimento 2 fez-se necessário checar a efetividade da ação do ETOH nos resultados obtidos. Animais foram divididos em 3 grupos (n=3) que receberam 0,00; 0,03 e 0,06mL de ETOH/kg de peso vivo. Uma hora após a aplicação do ETOH todos receberam E2 (3mg). O ETOH e o E2 voltaram a estimular a produção de PGFM. A baixa especificidade do RU486, a possível ativação de receptores de P4 pelo próprio RU486 e/ou ação do LH associado ao E2 podem ter estimulado a liberação de PGFM. Porém pouco pôde-se concluir sobre o pico de PGFM ocasionado pelo ETOH.Estradiol (E2) is essential for triggering luteolysis in ruminants. The low E2 concentrations after follicular ablation prolongs luteolysis instead of E2 injections in late luteal phase stimulate prostaglandin F2α (PGF2α) and luteolysis. The E2 could act in endometrium avoiding progesterone (P4 ) to stimulate PGF 2α secretion. A P4 antagonist (RU486) was used for it. Holstein cows in late luteal phase where used for those 2 experiments. First experiment, 2 groups (n=4) received respectively RU486 (3mg/kg)+E2 (3mg) and placebo+E2 Ru486 increased PGFM (PGF2α metabolite). E2 stimulated PGFM production. Ethanol (ETOH) used as a RU486 vehicle strongly stimulated PGFM. In experiment 2 the effectivity of ETOH was studied. Animals were share into 3 groups (n=3) receiving 0,00; 0,03 e 0,06mL of ETOH/kg. All animals received E2 (3mg) 1hour after ETOH injection. Once more, both ETOH and E2 stimulated PGFM releasing. The low RU486 specificity, the possible P4 receptor activation by the RU486 itself and/or the LH/E2 association could be able to stimulate PGFM release. The PGFM stimulus by the ETOH injection is not well understood.
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Ho, Chi Keung (Jimmy). "Effects of elevated temperatures on electrochemical processes and electrocatalysis and adsorption in the oxygen evolution reaction at alpha and beta lead dioxides." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6573.
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The first part of the thesis is concerned with the problem of temperature dependence of the Tafel slope for various electrochemical processes including the cathodic H$\sb2$ and anodic O$\sb2$ evolution reactions at Au, Pt and Ni in 0.2 N NaOH aqueous solutions at elevated temperatures up to 473 K by means of steady-state polarization experiments. It is found that the commonly assumed representation of the Tafel slope, b, as b = RT/$\beta$F with $\beta$ a constant, often equal to 0.5, is not followed, i.e. $\beta$ is dependent on T. Several examples of this unconventional behaviour of b on temperature are provided in this thesis. The effect of temperature on the surface processes of oxide film formation and reduction in both acid and alkaline aqueous solutions is also examined by means of cyclic voltammetry experiments at temperatures as high as 529 K. In addition to the expected behaviour, such as the higher is the temperature the larger is the rate of reaction, the processes also become more reversible. Experimental examples are provided in this thesis. The second part of the thesis is about the anodic O$\sb2$ evolution reaction at the two "allotropic" forms of lead dioxide, $\alpha$- and $\beta$-PbO$\sb2$ in 1 N HClO$\sb4$ aqueous solutions. The existence of these two forms of PbO$\sb2$ provides a rare opportunity of examining the structural effect in electrocatalysis and kinetics of the O$\sb2$ evolution process. Significant differences between the dimorphs are observed both in the kinetics and the adsorption behaviour of the O and OH intermediates of the reaction. Both potential-relaxation transients, following prior current interruption, and a.c. frequency-response spectroscopy are used in deriving the adsorption behaviour of the reaction intermediates, both H and O/OH species.
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Jaoua, Nouha. "Estimation Bayésienne non Paramétrique de Systèmes Dynamiques en Présence de Bruits Alpha-Stables." Phd thesis, Ecole Centrale de Lille, 2013. http://tel.archives-ouvertes.fr/tel-00929691.
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Dans un nombre croissant d'applications, les perturbations rencontrées s'éloignent fortement des modèles classiques qui les modélisent par une gaussienne ou un mélange de gaussiennes. C'est en particulier le cas des bruits impulsifs que nous rencontrons dans plusieurs domaines, notamment celui des télécommunications. Dans ce cas, une modélisation mieux adaptée peut reposer sur les distributions alpha-stables. C'est dans ce cadre que s'inscrit le travail de cette thèse dont l'objectif est de concevoir de nouvelles méthodes robustes pour l'estimation conjointe état-bruit dans des environnements impulsifs. L'inférence est réalisée dans un cadre bayésien en utilisant les méthodes de Monte Carlo séquentielles. Dans un premier temps, cette problématique a été abordée dans le contexte des systèmes de transmission OFDM en supposant que les distorsions du canal sont modélisées par des distributions alpha-stables symétriques. Un algorithme de Monte Carlo séquentiel a été proposé pour l'estimation conjointe des symboles OFDM émis et des paramètres du bruit $\alpha$-stable. Ensuite, cette problématique a été abordée dans un cadre applicatif plus large, celui des systèmes non linéaires. Une approche bayésienne non paramétrique fondée sur la modélisation du bruit alpha-stable par des mélanges de processus de Dirichlet a été proposée. Des filtres particulaires basés sur des densités d'importance efficaces sont développés pour l'estimation conjointe du signal et des densités de probabilité des bruits
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Aguirre, Andrea Garafulic. "A diversidade da regeneração natural e fatores que podem influenciar o aumento da riqueza regenerante em áreas em processo de restauração com distintas idades /." Rio Claro, 2019. http://hdl.handle.net/11449/183187.
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Orientador: Massanori TakakiResumo: Grandes iniciativas mundiais no esforço de alavancar um aumento na restauração ecológica surgiram recentemente, como a Iniciativa 20 x 20 e a Bonn Challenge, que apresentam como meta conjunta restaurar 500 milhões de hectares até 2030. Assim, uma das metas da ecologia aplicada à restauração é buscar compreender as distintas maneiras pelas quais a vegetação varia durante o processo de restauração e quais fatores influenciam o aumento da riqueza de espécies regenerantes. Este trabalho teve como objetivos: (1) Compreender como variam a abundância relativa e riqueza rarefeita, quando se comparam a regeneração natural total e específica (espécies que ocorreram apenas na área de referência), nas áreas em restauração com diferentes idades. (2) Avaliar como variam a diversidade alfa e beta nas áreas em restauração com idades distintas. (3) Observar a variação na abertura do dossel nas áreas com idades distintas. (4) Analisar se as variáveis da abertura do dossel e a idade são fatores importantes no que tange à influência com o aumento da riqueza de espécies regenerantes. Nove áreas em processo de restauração, localizadas no município de Extrema (Minas Gerais), foram selecionadas com 4, 7 e 10 anos de idade e um fragmento de referência, onde ao todo, 360 parcelas foram instaladas. Em cada parcela foram mensurados todos os regenerantes entre 20 cm e 2 m de altura (ervas, trepadeiras, arbustos, arbóreas e pteridófitas). Resultados: Foram encontrados 6788 regenerantes. As herbáceas e arb... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Major global initiatives in an effort to leverage an increase in the ecological restoration areas have recently emerged, such as the 20 x 20 Initiative and the Bonn Challenge, which aim to restore together 500 million hectares by 2030. Thus, one of the goals of ecology applied to restoration is to look at the different ways in which vegetation varies during the restoration process and what factors influence the increase of regenerating species richness. This work has as objectives: (1) To understand how the relative abundance and rarefied richness vary, when comparing the total and specific natural regeneration (species that occurred only in the reference area) in restoration areas having varying ages. (2) To evaluate how alpha and beta diversity varies in areas of restoration of different ages. (3) To observe the variation in canopy opening in areas of different ages. (4) To analyze whether the variable canopy opening and age are important factors in the influence or relation with the increase of the richness of regenerating species. Nine areas aged 4,7 and 10 under restoration process were selected and a reference fragment, in which a total of 360 parcels were installed. All the areas are located in the Municipality of Extrema, Minas Gerais. In each plot was measured all regenerants between 20 cm and 2 m in height (herbs, climbers, shrubs, trees and pteridophytes). Results: 6788 regenerants were found. Herbs and trees had the highest relative abundances, general and specifi... (Complete abstract click electronic access below)
Doutor
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PAES, VANESSA P. "Caracterizacao radioquimica do sup(226)Ra, sup(40)K e dos isotopos de uranio e torio no fosfogesso." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10917.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Saad, Carla Gonçalves Schahin. "Baixos níveis de esclerostina: preditor de processo inflamatório persistente em pacientes com espondilite anquilosante sob terapia anti-TNFα." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5164/tde-09012013-180110/.
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Introdução: Baixas concentrações séricas de esclerostina foram descritas em pacientes com Espondilite Anquilosante (EA). No entanto, não existem dados sobre a importância deste inibidor da via de sinalização Wnt em pacientes com EA durante o tratamento com anti fator de necrose tumoral alfa (TNFa). Objetivos: Avaliar longitudinalmente os níveis séricos de esclerostina e sua associação com inflamação e densidade mineral óssea (DMO) em pacientes com EA em tratamento com anti-TNFa. Métodos: Trinta pacientes com EA em atividade foram avaliados no início, 6 e 12 meses, após terapia anti-TNFa em relação aos parâmetros clínicos (BASDAI, BASFI, BASMI e ASQoL), marcadores inflamatórios e dano radiológico basal (mSASSS). Trinta indivíduos saudáveis pareados por idade e sexo constituíram o grupo controle. As análises laboratoriais de esclerostina e da ligação de esclerostina ao receptor LRP6 e a DMO foram realizadas nos pacientes nos mesmos períodos de avaliação e comparadas aos controles. Resultados: Na avaliação inicial, pacientes com EA apresentavam menores concentrações séricas de esclerostina [60,5 (32,7) vs. 96,7 (52,9) pmol/l,P=0,002] e níveis similares de ligação de esclerostina ao receptor LRP6 (P=0,387) em relação aos controles. Foi observado melhora do BASDAI, BASFI, BASMI, ASQoL comparando tempo basal vs. 6 vs. 12 meses (P<0,01). Concomitantemente, observou-se um aumento gradual da DMO da coluna lombar (P<0,001) e no início do estudo os pacientes apresentavam uma correlação positiva entre avaliação radiológica basal (mSASSS) e a DMO da coluna lombar (r=0,468, P<0,01). Foi observada também uma redução dos marcadores inflamatórios comparando tempo basal vs. 6 vs. 12 meses (P<0,01). Os níveis de esclerostina aumentaram progressivamente após o tratamento com anti-TNFa [60,5 (32,7) vs. 67,1 (31,9) vs. 72,7 (32,3) pmol/l, P<0,001]. Entretanto, após 12 meses de terapia anti-TNFa as concentrações séricas de esclerostina permaneceram significativamente mais baixos em relação os controles [72,7 (32,3) vs. 96,7 (52,9) pmol/l, P=0,038]. Além disso, aos 12 meses, os níveis séricos de esclerostina ficaram mais baixos nos 10 pacientes que ainda apresentavam proteína C reativa elevada (PCR=5mg/l), comparados aos pacientes que apresentaram normalização dos níveis de PCR (P=0,004). Interessantemente, estes 10 pacientes com inflamação persistente já apresentavam concentrações séricas mais baixas de esclerostina quando comparados aos demais pacientes (P=0,023) antes do tratamento com anti- TNFa. A análise de regressão logística demonstrou que os pacientes com EA com níveis baixos de esclerostina apresentam um risco aumentado de apresentar PCR alta após 12 meses de tratamento (odds ratio = 7,43, 95% IC 1,23-45,01, P=0,020) quando comparados aos pacientes com níveis altos de esclerostina no tempo basal. Conclusão: Concentrações persistentemente baixas de esclerostina estão associados a inflamação contínua em pacientes com EA tratados com terapia anti-TNFa.Introduction: Sclerostin levels have been reported to be low in ankylosing spondylitis (AS), but there is no data regarding the possible role of this Wnt inhibitor during anti tumor necrosis factor alpha (TNFa) therapy. Objectives: The present study longitudinally evaluated sclerostin levels, inflammatory markers and bone mineral density (BMD) in AS patients under anti-TNFa therapy. Methods: Thirty active AS patients were assessed at baseline, 6 and 12 months after anti-TNFa therapy regarding clinical parameters (BASDAI, BASFI, BASMI and ASQoL), inflammatory markers, BMD and baseline radiographic damage (mSASSS). Thirty age- and sex-matched healthy individuals comprised the control group. Patients\' sclerostin levels, sclerostin binding LRP6 and BMD were evaluated at the same time points and compared to controls. Results: At baseline, AS patients had lower sclerostin levels [60.5 (32.7) vs. 96.7 (52.9) pmol/l, P=0.002] and comparable sclerostin binding to LRP6 (P=0.387) than controls. Improvement of BASDAI, BASFI, BASMI, ASQoL was observed at baseline vs. 6 vs. 12 months (P<0.01). Concomitantly, a gradual increase in spine BMD (P<0.001) and a positive correlation between baseline mSASSS and spine BMD was found (r=0.468, P<0.01). Inflammatory parameters reduction was observed comparing baseline vs. 6 vs. 12 months (P<0.01). Sclerostin levels progressively increased [60.5 (32.7) vs. 67.1 (31.9) vs. 72.7 (32.3) pmol/l, P<0.001] after anti-TNFa treatment. At 12 months, the sclerostin levels remained significantly lower in patients compared to controls [72.7 (32.3) vs. 96.70 (52.85) pmol/l, P=0.038]. Moreover, sclerostin serum levels at 12 months were lower in the 10 patients with high CRP (=5mg/l) compared to the other 20 patients with normal CRP (P=0.004). Of note, these 10 patients with persistent inflammation also had lower sclerostin serum levels at baseline compared to the other patients (P=0.023). Univariate logistic regression analysis demonstrated that AS patients with lower sclerostin serum levels had an increased risk to have high CRP at 12 months (odds ratio=7.43, 95% CI 1.23-45.01, P=0.020) than those with higher sclerostin values. Conclusion: Persistent low sclerostin levels may underlie continuous inflammation in AS patients under anti-TNFa therapy.
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Nötel, Jörg. "Active Brownian Particles with alpha Stable Noise in the Angular Dynamics: Non Gaussian Displacements, Adiabatic Eliminations, and Local Searchers." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/19681.
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Das Konzept von aktiven Brownschen Teilchen kann benutzt werden, um das Verhalten einfacher biologischer Organismen oder
künstlicher Objekte, welche die Möglichkeit besitzen sich von selbst fortzubewegen zu beschreiben.
Als Bewegungsgleichungen für aktive Brownsche Teilchen kommen Langevin Gleichungen zum Einsatz.
In dieser Arbeit werden aktive Teilchen mit konstanter Geschwindigkeit diskutiert. Im ersten Teil der Arbeit wirkt auf die Bewegungsrichtung
des Teilchen weißes alpha-stabiles Rauschen. Es werden die mittlere quadratische Verschiebung und der effektive Diffusionskoeffizient bestimmt.
Eine überdampfte Beschreibung, gültig für Zeiten groß gegenüber der Relaxationszeit wird hergleitet. Als experimentell zugängliche Meßgröße,
welche als Unterscheidungsmerkmal für die unterschiedlichen Rauscharten herangezogen werden kann, wird die Kurtose berechnet. Neben weißem Rauschen
wird noch der Fall eines Ornstein-Uhlenbeck Prozesses angetrieben von Cauchy verteiltem Rauschen diskutiert. Während eine normale Diffusion
mit zu weißem Rauschen identischem Diffusionskoeffizienten bestimmt wird, kann die beobachtete Verteilung der Verschiebungen Nicht-Gaußförmig
sein. Die Zeit für den Übergang zur Gaußverteilung kann deutlich größer als die Zeitskale Relaxationszeit und die Zeitskale des Ornstein-Uhlenbeck
Prozesses sein. Eine Grenze der benötigten Zeit wird durch eine Näherung der Kurtosis ermittelt.
Weiterhin werden die Grundlagen eines stochastischen Modells für lokale Suche gelegt. Lokale Suche ist die Suche in der näheren Umgebung
eines bestimmten Punktes, welcher Haus genannt wird. Abermals diskutieren wir ein aktives Teilchen mit unveränderlichem Absolutbetrag der
Geschwindigkeit und weißen alpha-stabilem Rauschen in der Bewegungsrichtungsdynamik. Die deterministische Bewegung des Teilchens wird
analysiert bevor die Situation mit Rauschen betrachtet wird. Die stationäre Aufenthaltswahrscheinlichkeitsdichtefunktion wird bestimmt. Es wird
eine optimale Rauschstärke für die lokale Suche, das heißt für das Auffinden eines neuen Ortes in kleinstmöglicher Zeit festgestellt. Die
kleinstmögliche Zeit wird kaum von der Rauschart abhängen. Wir werden jedoch feststellen, dass die Rauschart deutlichen Einfluß auf die
Rückkehrwahrscheinlichkeit zum Haus hat, wenn die Richtung des zu Hauses fehlerbehaftet ist. Weiterhin wird das Model durch eine
an das Haus abstandsabhängige Kopplung
erweitert werden. Zum Abschluß betrachten wir eine Gruppe von Suchern.Active Brownian particles described by Langevin equations are used to model the behavior of simple biological organisms or artificial objects that are able to perform self propulsion. In this thesis we discuss active particles with constant speed. In the first part, we consider angular driving by white Levy-stable noise and we discuss the mean squared displacement and diffusion coefficients. We derive an overdamped description for those particles that is valid at time scales larger the relaxation time. In order to provide an experimentally accessible property that distinguishes between the considered noise types, we derive an analytical expression for the kurtosis. Afterwards, we consider an Ornstein-Uhlenbeck process driven by Cauchy noise in the angular dynamics of the particle. While, we find normal diffusion with the diffusion coefficient identical to the white noise case we observe a Non-Gaussian displacement at time scales that can be considerable larger than the relaxation time and the time scale provided by the Ornstein-Uhlenbeck process. In order to provide a limit for the time needed for the transition to a Gaussian displacement, we approximate the kurtosis. Afterwards, we lay the foundation for a stochastic model for local search. Local search is concerned with the neighborhood of a given spot called home. We consider an active particle with constant speed and alpha-stable noise in the dynamics of the direction of motion. The deterministic motion will be discussed before considering the noise to be present. An analytical result for the steady state spatial density will be given. We will find an optimal noise strength for the local search and only a weak dependence on the considered noise types. Several extensions to the introduced model will then be considered. One extension includes a distance dependent coupling towards the home and thus the model becomes more general. Another extension concerned with an erroneous understanding by the particle of the direction of the home leads to the result that the return probability to the home depends on the noise type. Finally we consider a group of searchers.
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Pesee, Chatchai. "Stochastic Modelling of Financial Processes with Memory and Semi-Heavy Tails." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16057/.
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This PhD thesis aims to study financial processes which have semi-heavy-tailed marginal distributions and may exhibit memory. The traditional Black-Scholes model is expanded to incorporate memory via an integral operator, resulting in a class of market models which still preserve the completeness and arbitragefree conditions needed for replication of contingent claims. This approach is used to estimate the implied volatility of the resulting model. The first part of the thesis investigates the semi-heavy-tailed behaviour of financial processes. We treat these processes as continuous-time random walks characterised by a transition probability density governed by a fractional Riesz- Bessel equation. This equation extends the Feller fractional heat equation which generates a-stable processes. These latter processes have heavy tails, while those processes generated by the fractional Riesz-Bessel equation have semi-heavy tails, which are more suitable to model financial data. We propose a quasi-likelihood method to estimate the parameters of the fractional Riesz- Bessel equation based on the empirical characteristic function. The second part considers a dynamic model of complete financial markets in which the prices of European calls and puts are given by the Black-Scholes formula. The model has memory and can distinguish between historical volatility and implied volatility. A new method is then provided to estimate the implied volatility from the model. The third part of the thesis considers the problem of classification of financial markets using high-frequency data. The classification is based on the measure representation of high-frequency data, which is then modelled as a recurrent iterated function system. The new methodology developed is applied to some stock prices, stock indices, foreign exchange rates and other financial time series of some major markets. In particular, the models and techniques are used to analyse the SET index, the SET50 index and the MAI index of the Stock Exchange of Thailand.
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Di, Francesco Michele. "Scenari incidentali di un deposito di liquidi infiammabili." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8471/.
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Il seguente lavoro di Tesi ha ad oggetto l’analisi degli scenari incidentali che possono originarsi in un deposito di oli minerali dichiarato a rischio di incidente rilevante.
La Tesi è strutturata come descritta di seguito.
Dopo il presente Capitolo 1, avente carattere introduttivo, il Capitolo 2 descrive nel dettaglio lo stabilimento PIR di Porto Corsini-Ravenna, dedicando particolare attenzione alle normative a cui è soggetto. Nel Capitolo 3 si è eseguita una valutazione delle conseguenze e delle frequenze degli scenari incidentali, analizzando criticamente i risultati dell’analisi delle conseguenze ed i valori di frequenza riportati nei documenti predisposti ai fini del D.Lgs. 334/99 e s.m.i. e alle norme ad esso correlate. Inoltre sono state fatte alcune considerazioni sull’effetto domino. Nel Capitolo 4 infine sono riportate alcune considerazioni conclusive.
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Almeida, Carla França Wolanski de. "Estudo de um laboratório destinado ao controle em processo do biofármaco interferon alfa 2b humano recombinante." Instituto de Tecnologia em Imunobiológicos, 2009. https://www.arca.fiocruz.br/handle/icict/5843.
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Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.
Controle em processo é parte das ações para garantia da qualidade dos produtos a fim de que eles atendam aos requisitos mínimos estabelecidos para seu uso. Os resultados obtidos nos ensaios orientam na tomada de decisões, bem como em ajustes ao processo de produção. Muitas vezes tais resultados são condições imperativas para as etapas subsequentes. O monitoramento do processo produtivo se dá a partir do estabelecimento dos pontos críticos de controle, que precisam ser verificados a cada lote, pois interferem diretamente na qualidade e rendimentos da produção. Portanto, a confiabilidade e agilidade deresposta são fundamentais para correta tomada de decisão e/ou ajuste. O objetivo deste trabalho é propor um modelo de laboratório de controle em processo nos aspectos gerenciais e principalmente nos aspectos técnicos aplicados ao processo de produção do biofármaco Interferon alfa 2b humano recombinante. Este produto, oferecido no portfólio de Bio-Manguinhos encontra-se em processode transferência de tecnologia com o Instituto cubano CIGB. Com base nos dados da literatura foram estabelecidas as principais etapas do processo produtivo a para expressão de proteínas heterólogas, em sistema recombinante utilizando-se a bactéria Escherichia coli. Os pontos críticos de controle foram estabelecidos utilizando-se a metodologia de análise de riscos HACCP (Hazard Analisys Critical Control Point). Para as análises de controle foram propostas metodologias analíticas que proporcionem a consistência de resultados e que possam garantir a qualidade final do processo de manufatura do produto. O modelo proposto também enfatiza a conduta de ações rotineiras de forma que qualquer desvio possa ser imediatamente identificado e suas causas apuradas além de executar as análises com segurança. Os critérios gerenciais e técnicos abordados foram avaliados criticamente, utilizando-se os procedimentos do sistema de garantia da qualidade vigentes no Instituto, bem como na estrutura do laboratório de controle em processodestinado à vacina contra Hib, que foi adotado como premissa básica, fruto da transferência de tecnologia bem sucedida em Bio-Manguinhos. A proposta elaborada poderá ser utilizada em outros laboratórios destinados ao controle em processo de novos produtos em Bio-Manguinhos e enfatiza os critérios técnicos como condicionais para confiabilidade de medição.
In-process control is a part of the actions to guarantee the quality for final products in order to attend the minimum requirements established for their using. The results obtained from analytical assays guide on decision-making as well as production process adjustments. Often, these results are conditioned to the follow the subsequent stages. The process monitoring occurs from the establishment of critical control points to verify in each batch because theydeterminate product quality and process yield. Therefore, the reliability and speedof response are critical for correct decision-making and adjustment. The objective of this work is to propose a model in process control laboratory in management aspects and especially the technical aspects applied to the production of human recombinant interferon alpha 2b biopharmaceutical, object of this study. Bio-Manguinhos supplies this product in its portfolio, which production technology is being transferred from the CIGB, a Cuban Institution. Based on literature data the main steps were established for a production process of heterologous proteins expressed using a recombinant system with the Escherichia colibacteria. The critical control points were established using the risk assessment methodology HACCP, Hazard analysis Critical Control, HACCP. Analytical methodologies were proposed to improve results consistency and assure the final quality of production process. The proposed model emphasizes the routine actions, so that, any deviation could be immediately identified, their causes verified and activities performed reliably. The management and technical criteria described have been critically evaluated using the Bio-Manguinhos institute quality assurance procedures as well as compared to the structure of the in-process control laboratory for Hib vaccine. This laboratory, adopted as basic premise, resulted from a successful technology transfer in Bio-Manguinhos. The proposal drawn up can be used in other laboratories for in- process control in new products in Bio-Manguinhos and emphasizes the technical criteria for conditional measurement reliability.
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Boulanger, Frédéric. "Modelisation et simulation de variables regionalisees par des fonctions aleatoires stables." Paris, ENMP, 1990. http://www.theses.fr/1990ENMP0195.
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Dans cette these, nous proposons de travailler sur la classe des fonctions aleatoires stables pour la modelisation et simulation de variables regionalisees. Dans la premiere partie, nous abordons le probleme de la realisation d'une fonction de covariance. Nous proposons deux methodes permettant d'une part d'etablir, par une nouvelle approche, les principaux resultats concernant les processus auttoregressifs a moyennes mobiles et d'autre part de calculer les parametres associes. Enfin, nous abordons le probleme de la simulation conditionnelle pour lequel nous proposons une solution directe en voisinage glissant. Dans la seconde partie, nous introduisons les fonctions aleatoires stables. Apres un rapide rappel des definitions des lois stables reelles et vectorielles, nous abordons le probleme de l'adequation de ce modele (de variance infinie) aux variables regionalisees (de variance experimentale finie). Apres une etude des differentes methodes existantes, il nous est apparu qu'il n'existait pas de tests de stabilite performants. Nous proposons deux tests reposant sur l'etude de la fonction caracteristique experimentale. Cette etude permet dans le meme temps d'ameliorer les methodes d'estimation des parametres d'une loi stable, notamment pour les petits echantillons. Une fois l'hypothese de stabilite acceptee, il est indispensable de passer a l'etape de l'analyse structurale. Dans cette optique, nous avons developpe une methode d'estimation semi-parametrique des lois stables vectorielles. Si la methode fournit des resultats interessants dans le cadre d'une loi stable, il semble que la methode ne puisse pas etre utilisee pour l'estimation de toutes les lois finies dimensionnelles. Nous avons donc propose deux outils d'analyse structurale plus simples generalisant la notion de covariance, la fonction d'autocorrelation experimentale et l'alpha-variogramme. Apres une etude generale des fonctions aleatoir
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Komaty, Ali. "Traitement et analyse des processus stochastiques par EMD et ses extensions." Thesis, Brest, 2014. http://www.theses.fr/2014BRES0107.
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L’objectif de cette thèse est d’analyser le comportement de la décomposition modale empirique (EMD) et sa version multivariée (MEMD) dans le cas de processus stochastiques : bruit Gaussien fractionnaire (fGn) et processus symétrique alpha stable (SαS). Le fGn est un bruit large bande généralisant le cas du bruit blanc Gaussien et qui trouve des applications dans de nombreux domaines tels que le trafic internet, l’économie ou le climat. Par ailleurs, la nature «impulsive» d’un certain nombre de signaux (craquement des glaces, bruit des crevettes claqueuses, potentiel de champ local en neurosciences,…) est indéniable et le modèle Gaussien ne convient pas pour leur modélisation. La distribution SαS est une solution pour modéliser cette classe de signaux non-Gaussiens. L’EMD est un outil bien adapté au traitement et à l’analyse de ces signaux réels qui sont, en général, de nature complexe (non stationnaire,non linéaire). En effet, cette technique, pilotée par les données, permet la décomposition d’un signal en une somme réduite de composantes oscillantes, extraites de manière itérative, appelées modes empiriques ou IMFs (Intrinsic Mode Functions). Ainsi, nous avons montré que le MEMD s’organise spontanément en une structure de banc de filtres presque dyadiques. L'auto-similarité en termes de représentation spectrale des modes a aussi été établie. En outre, un estimateur de l’exposant de Hurst, caractérisant le fGn, a été construit et ses performances ont été comparées, en particulier à celles de l’approche ondelettes. Cette propriété de banc de filtres du MEMD a été vérifiée sur des données d'hydrodynamique navale (écoulement turbulent) et leur auto-similarité a été mise en évidence. De plus, l’estimation du coefficient de Hurst a mis en avant l’aspect longue dépendance (corrélation positive) des données. Enfin, l’aspect banc de filtres de l’EMD a été exploité à des fins de filtrage dans le domaine temporel en utilisant une mesure de similarité entre les densités de probabilités des modes extraits et celle du signal d’entrée. Pour éviter le problème du mode mixing de l'EMD standard, une approche de débruitage dans le domaine fréquentiel par une reconstruction complète des IMFs préalablement seuillées a été menée. L’ensemble des résultats a été validé par des simulations intensives (Monte Carlo) et sur des signaux réelsThe main contribution of this thesis is aimed towards understanding the behaviour of the empirical modes decomposition (EMD) and its extended versions in stochastic situations
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Côrtes, Andréa Junqueira. "Avaliação do efeito da matriz derivada do esmalte (Emdogain®) sobre o processo de cicatrização de feridas cutâneas cirúrgicas em ratos Wistar." Universidade Federal de Juiz de Fora, 2014. https://repositorio.ufjf.br/jspui/handle/ufjf/713.
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A matriz derivada do esmalte (EMD) é um complexo proteico de origem ectodérmica, isolado de germes dentários em desenvolvimento. Originalmente utilizada na regeneração de tecidos do periodonto, vem se mostrando um excelente recurso na regeneração de outros tecidos mesenquimais como derme, tecido ósseo e tendão. No presente estudo, o potencial cicatrizante da matriz foi analisado histopatologicamente em feridas cutâneas cirúrgicas realizadas em ratos Wistar, eutanaziados nos dias 01, 03, 07, 14 e 21. Durante o experimento, as feridas foram acompanhadas macroscopicamente e, a seu término, foram removidas e submetidas ao processamento histológico. À avaliação microscópica, foi observado que as lesões tratadas com a EMD evoluíram para o remodelamento dérmico de modo mais eficaz em tempo e qualidade em relação ao grupo controle não tratado, a partir do 3º dia pós-operatório; o amadurecimento e organização do colágeno foi bastante evidente a partir do 7º dia e, destaca-se que nos dias 14 e 21 o plano muscular, na profundidade da pele, exibiu excelente regeneração, sendo que, também neste período, o amadurecimento vascular se mostrou mais significativa nas amostras tratadas. Além da análise histomorfométrica, foi realizada a avaliação da expressão de iNOS, TGF- β2 e TNF-α por imunoistoquímica. A expressão de iNOS foi significativamente mais expressiva nas amostras tratadas, aumentando progressivamente a partir do 7º dia pós-operatório. Os resultados sugerem que a EMD, aplicada em feridas cutâneas cirúrgicas, potencializa a neoformação e o remodelamento de colágeno, amadurecimento vascular e regeneração muscular possivelmente via modulação do óxido nítrico.
The enamel matrix derivative (EMD) is a protein complex of ectodermal origin, isolated from the developing tooth germs. Originally used in the regeneration of periodontal tissues, has proved to be an excellent resource in the regeneration of other mesenchymal tissues such as dermis, bone and tendon. In the present study, the healing potential of the matrix was analyzed histologically in surgical wounds made in Wistar rats, euthanized on days 01, 03, 07, 14 and 21. During the experiment, the wounds were followed macroscopically, and at its end, were removed and subjected to histological processing. For microscopic evaluation, it was observed that the lesions treated with EMD progressed to dermal remodeling more effectively in time and quality in relation to the untreated control group, from the 3th postoperative day ; the maturation and organization of the collagen was quite evident from the 7th day , and it is noteworthy that on 14 and 21 muscle -up, the skin depth, showed excellent regeneration, and also in this period, vascular maturation showed more significantly in the treated samples. In histomorphometric analysis, evaluation of iNOS, TGF- β2, and TNF-α expression was performed by immunohistochemistry. The expression of iNOS was significantly more expressive in the treated samples, increasing progressively from the 7th postoperative day. The results suggest that EMD applied on surgical wounds enhances the new formation and remodeling of collagen, vascular maturation and muscle regeneration possibly via modulation of nitric oxide.
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Nathan, Roger P. "Numerical modelling of environmental dose rate and its application to trapped-charge dating." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:3da656e8-5514-4fed-85d1-8664e5dc1932.
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Accurate estimation of environmental dose rate is essential for high-resolution trapped-charge dating. Beta and gamma emissions from simulated sediments containing radioactive uranium, thorium and potassium are modelled in contexts that are spatially heterogeneous. Dose rate was modelled using Monte Carlo radiation transport codes MCNP and PENELOPE. A number of key issues that affect dose rate evaluation are examined and updated corrections are calculated. Granular structures used for geometrical input into the models were simulated using randomly packed ellipsoids. The pair correlation function and chord length distributions were derived. The effects of water content on dose rate were modelled and compared with cavity theory. Apart from activity dilution, the variation of grain size or water content was shown to be significant for gamma radiations due to the transition from charged particle equilibrium. The standard correction for beta dose rate due to grain size was found to be satisfactory although sensitivity to grain shape and material should be taken into account. Dose rate modeling was applied to three dating studies of early human fossils: Skhul V, Israel skull; Hofmeyr, South Africa skull and the Forbes’ Quarry, Gibraltar skull. The spatial modelling was implemented using computerised tomographic (CT) images and dose rate found to be modified significantly by the presence of the skull in the sediment. Time evolution of the dose rate was examined for the latter two skulls and dates of 36±3ka (Hofmeyr) and 55-95ka (Forbes’ Quarry) were calculated.
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Meola, Alessia. "Sviluppo di una procedura di calcolo del rischio locale dovuto a rilasci accidentali di sostanze tossiche." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Il Laboratorio PQAT dell’IQS School of Engineering lavora come ente valutatore delle analisi del rischio e delle analisi quantitative del rischio che gli stabilimenti chimici situati nel territorio catalano e soggetti alla normativa Seveso presentano alla Generalitat de Catalunya. Le analisi del rischio sono importanti ai fini della protezione della popolazione mentre le analisi quantitative del rischio sono utilizzate nella pianificazione territoriale.
Nel procedimento di valutazione si realizzano differenti fasi di calcolo, alcune operate manualmente altre attraverso l’utilizzo di software. Nel caso di un rilascio accidentale di sostanze tossiche, il laboratorio PQAT utilizza i software EFFECTS e ALOHA per il calcolo delle conseguenze, un foglio di calcolo Excel per la valutazione della probabilità di morte e genera le curve isorischio attraverso un programma proprio implementato in MATLAB. L’obiettivo del seguente lavoro è migliorare e automatizzare il calcolo della curva isorischio per conseguenze di tipo tossico attraverso la creazione di un codice MATLAB. Il programma sviluppato permette di calcolare in maniera automatizzata i valori della probabilità di morte in caso di rilasci di sostanze tossiche, semplicemente attraverso le informazioni relative al rilascio e alla sostanza senza dover ricorrere all’utilizzo di software esterni per la valutazione delle conseguenze fisiche e senza l’utilizzo del foglio di calcolo Excel per la valutazione della probabilità di morte. Il programma oltre ad essersi dimostrato più accurato permette di evitare due fasi laboriose della procedura per la realizzazione di una analisi quantitativa del rischio. Il programma creato è stato successivamente collegato al programma sviluppato dal laboratorio PQAT per il calcolo delle curve isorischio, rendendo così il calcolo automatizzato.
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Santos, Sânia Alves dos. "Análise comparativa do processo de invasão de hepatócitos de rato por Listeria monocytogenes e Salmonella Typhimurium: caracterização morfológica, quantificação da liberação de TNF-alfa e da morte celular por apoptose." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/5/5134/tde-15042009-150702/.
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INTRODUÇÃO: Os hepatócitos apresentam papel potencial em iniciar e amplificar a resposta inflamatória aguda no fígado, através da liberação de citocinas pró-inflamatórias, em papel complementar ao exercido pelas células de Kupffer e endoteliais. A invasão bacteriana da célula hepática é um estímulo para que o hepatócito produza citocinas como o TNF-alfa, capaz de induzir sua própria morte por apoptose. O TNF-alfa pode ser tanto um agente citotóxico (induzindo a morte celular), quanto um agente protetor (através da ativação de NF-kB). A morte por apoptose do hepatócito libertaria as bactérias que seriam destruídas pelo sistema imunológico hepático ativado. Salmonella Typhimurium (ST) e Listeria monocytogenes (LM) são patógenos responsáveis por importantes doenças de origem alimentar. O hepatócito é o maior local de replicação bacteriana no fígado. As conseqüências da invasão bacteriana dos hepatócitos e sua repercussão na produção de TNF-alfa e na morte celular necessitam ser melhor xxix avaliadas. MÉTODOS: Nesse estudo procuramos investigar o comportamento dos hepatócitos invadidos por ST e LM sorogrupos 4a, 4b e 1/2a, analisando os seguintes parâmetros: a) morfologia = por microscopia óptica (MO) (hematoxilina e eosina) e por microscopia eletrônica (ME); b) dosagem do TNF-alfa liberado pelos hepatócitos invadidos = o TNF-alfa liberado foi detectado por técnica ELISA no sobrenadante das culturas; c) pesquisa da morte celular por apoptose = avaliada através das técnicas TUNEL e anexina (citometria de fluxo). Para todos os parâmetros foi realizada análise comparativa estatística entre os quatro tipos de bactéria. RESULTADOS: As monocamadas de hepatócitos agredidas por Listeria monocytogenes e Salmonella Typhimurium apresentam ruptura em sua distribuição, e sinais de desorganização citoplasmática e nuclear. Para as bactérias ST, LM 4a, LM 4b e LM 1/2a obtivemos os seguintes valores em seqüência: a) taxa de liberação de TNF-alfa (pg/mL): 146,9±18,38; 94,71±13,89; 94,52±15,66 e 58,16±15,49; b) capacidade de produção de TNF-alfa (pg/mL): -67,20±71,56; -46,49±54,10; -106,3±61,0 e 58,16±15,49; c) taxa de apoptose avaliada por TUNEL em unidade de área (UA): 23,86±1,614; 15,92±0,9343; 21,14±1,421 e 23,93±1,263; d) capacidades de produção de apoptose por TUNEL em UA: -50,67±12,42; 10,81±7,186; - 17,22±10,93 e -40,27±9,712; e) taxas de apoptose por anexina em UA: 12,51±2,052; 23,10±3,481; 26,61±3,414 e 18,57±2,497; f) capacidades de produção de apoptose por anexina em UA: -63,31±15,79; -126,4±26,78; - 142,0±26,26 e -97,75±19,21. CONCLUSÕES: a) ocorre liberação de TNFxxx alfa pelos hepatócitos invadidos, sendo que a Salmonella Typhimurium foi responsável pela maior taxa de liberação de TNF-alfa, e Listeria monocytogenes 4b pela maior capacidade de produção de TNF-alfa; b) ocorre morte por apoptose dos hepatócitos invadidos por bactérias, avaliada através da técnica TUNEL, sendo que Salmonella Typhimurium e Listeria monocytogenes 1/2a foram responsáveis pelas maiores taxas e capacidades de produção de apoptose; c) ocorre morte dos hepatócitos invadidos por apoptose, avaliada através da técnica da anexina, sendo que Listeria monocytogenes 4b foi responsável pelas maiores taxas e capacidades de produção de apoptose; d) os hepatócitos cultivados invadidos pelas bactérias Salmonella Typhimurium e Listeria monocytogenes apresentam alterações morfológicas, com ruptura da distribuição da monocamada, e sinais de desorganização citoplasmática e nuclearINTRODUCTION: Hepatocytes can play an important role in the initiation or amplification of the hepatic acute inflammatory response, through the release of proinflammatory cytokines. The bacterial invasion of hepatocyte is a stimulus for production of TNF-alpha by these cells, and this phenomenon induces its own death by apoptosis. TNF-alpha is as a cytotoxic agent (inducing cellular death), as a protector agent (through NF-kB activation). The hepatocyte death by apoptosis may release intracellular bacteria that would be destroyed by hepatic immunological system. Salmonella Typhimurium (ST) and Listeria monocytogenes (LM) are important foodborne pathogens. The hepatocyte is the major site of bacterial replication in the liver. The consequences of hepatocytes bacterial invasion must be better evaluated. METHODS: In the present work we show the behavior of hepatocytes invaded by ST and LM serotypes 4a, 4b and 1/2a, through: a) morphology = by optic microscopy (OM) (hematoxylin-eosin staining) and electronic microscopy (EM); b) quantification of TNF-alpha released by hepatocytes = TNF-alpha released was determined by ELISA in culture supernatants; c) evaluation of apoptotic cell death by TUNEL and annexin techniques (flow cytometry). For all parameters were made a statistical comparative analysis among the four types of bacteria. RESULTS: The hepatocytes monolayers invaded by LM and ST presented ruptures in your organization, and signs of nuclear and cytoplasmic disorder. For the bacteria ST, LM 4a, LM 4b and LM 1/2a we obtained the following values respectively: a) rate of TNF-alpha released (pg/mL): 146,9±18,38; 94,71±13,89; 94,52±15,66 and 58,16±15,49; b) capacities of TNF-alpha production (pg/mL): -67,20±71,56; -46,49±54,10; -106,3±61,0 and 58,16±15,49; c) rate of apoptosis by TUNEL in unit of area (UA): 23,86±1,614; 15,92±0,9343; 21,14±1,421 and 23,93±1,263; d) capacities of apoptosis production by TUNEL in UA: -50,67±12,42; 10,81±7,186; - 17,22±10,93 and -40,27±9,712; e) rate of apoptosis by annexin in UA: 12,51±2,052; 23,10±3,481; 26,61±3,414 and 18,57±2,497; f) capacities of apoptosis production by annexin in UA: -63,31±15,79; -126,4±26,78; - 142,0±26,26 and -97,75±19,21. CONCLUSIONS: a) ST was responsible for the major rate of TNF-alpha released and LM 4b was responsible for the major capacity of TNF-alpha production; b) ST and LM 1/2a caused the major rates and capacities of apoptosis,production, evaluated by TUNEL technique; c) LM 4b was responsible for the major rates and capacities of apoptosis production, evaluated by annexin technique; d) the cultured hepatocytes invaded by bacteria ST and LM presented morphological alterations, with monolayer rupture, and signs of nuclear and cytoplasmic disorder
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Schietke, Ruth Elisabeth. "Die Rolle von HIF bei zellulären Transformationsprozessen : I. HIF-2 alpha im renalen Tubulus ein transgenes Mausmodel : II. Identifizierung und Charakterisierung von Lysyloxidasen als tumorfördernde HIF-Zielgene = The role of HIF for cellular transformation processes /." kostenfrei, 2009. http://d-nb.info/993148441/34.
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Laurent, Clément. "Grandes déviations pour les temps locaux d'auto-intersections de marches aléatoires." Phd thesis, Université de Provence - Aix-Marseille I, 2011. http://tel.archives-ouvertes.fr/tel-00645783.
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Dans cette thèse on s'intéresse au temps local d'auto-intersections de marches aléatoires. Cette quantité est définie comme la norme-$p$ à la puissance $p$ du temps local de la marche. Elle regarde dans quelle mesure la trajectoire de la marche aléatoire s'intersecte. Le temps local d'auto-intersections est lié à différents modèles physiques comme les modèles de polymères ou les problèmes d'écoulements de flux en milieux stratifiés mais aussi au modèle mathématiques des marches aléatoires en paysages aléatoires. Nous nous sommes pour notre part intéressés en particulier aux grandes déviations du temps local d'auto-intersections, c'est à dire que nous regardons la probabilité que la quantité d'intersections de la marche aléatoire soit plus grande que sa moyenne. Cette question qui a été très étudiée au cours des années 2000 fait apparaitre trois cas distincts, le cas sous-critique, le cas critique et le cas sur-critique. Nous améliorons la connaissance sur cette question au travers de deux résultats complets et d'un résultat partiel. D'abord nous prouvons un principe de grandes déviations dans les cas critique et sur-critique des marches $\alpha$-stables, puis nous améliorons les échelles de déviations au cas sous-critique tout entier de la marche simple, enfin nous sommes en train d'étendre ce dernier résultat aux marches $\alpha$-stables. Par ailleurs les trois preuves sont basées sur l'utilisation d'une version due à Eisenbaum d'un théorème d'isomorphisme de Dynkin. Cette méthode d'abord introduite par Castell dans le cas critique est donc ici étendue aux autres cas. Nous avons donc réussi à unifier les différentes méthodes de preuves au travers ce théorème d'isomorphisme.
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Kalfa, Nicolas. "Tumeurs juvéniles de la granulosa : analyse moléculaire de la Gαs et des gènes de la détermination gonadique." Montpellier 1, 2006. http://www.theses.fr/2006MON1T010.
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Les tumeurs ovariennes des cordons sexuels sont des tumeurs rares qui se développent aux dépens des cellules non germinales de l'ovaire. Depuis deux décennies l'individualisation des tumeurs juvéniles de la granulosa a constitué une avancée majeure dans le traitement de ces tumeurs de l'enfant. Cependant leur physiopathologie reste indéterminée. L'objectif de cette thèse est de rechercher dans ces tumeurs une éventuelle implication de la voie de la signalisation de la Gαs et une dysrégulation de l'expression des gènes de la détermination gonadique. A travers une étude multicentrique nationale en collaboration avec la Société Française des Cancers de l'Enfant et 8 centres d'endocrinologie pédiatrique, incluant 46 patients, nous avons démontré 1- la présence de mutations activatrices de la protéine de transduction Gsα par microdissection laser, amplification sélective et séquençage dans 30% des tumeurs (R201H, R201C). Cette mutation constitue un facteur pronostique majeur de récidive et d'extension locorégionale de ces tumeurs. 2- l'efficacité et la fiabilité d'une nouvelle méthode de détection de ces mutations par PNA clamping, méthode également applicable au diagnostic précoce d'endocrinopathie de l'enfant (série de 150 ADN de syndrome de McCune-Allbright). 3- que l'extinction de FOXL2, gène clef de la détermination ovarienne, survient dans les tumeurs ayant un comportement agressif. 4- l'existence d'une dérégulation de l'expression des gènes de la détermination sexuelle (SOX9 et FOXL2) au sein de ces tumeurs, avec la possibilité de transdifférenciation, chez 3 patients XY porteurs de tumeur de la granulosa du testicule, de cellules de Sertoli en cellules de la granulosa tumorales. Au total, ces données contribuent à une nouvelle approche physiopathologique de développement des tumeurs de la granulosa tout en améliorant leur prise en charge médico-chirurgicale.
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Aït, Hennani Larbi. "Comportement asymptotique du processus de vraisemblance dans le cas non régulier." Rouen, 1989. http://www.theses.fr/1989ROUES039.
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Ce travail a pour point de départ les résultats de Ibragimov et Has'minskii concernant la convergence des lois marginales du processus de vraisemblance dans le cas où, la densité considérée, est de la forme f(x-t) et possède un nombre fini de singularités. Il a pour but la généralisation de ces résultats, et l'étude de la convergence en moyenne quadratique du processus de vraisemblance lorsqu'on remplace f(x-t) par f(x,t) où t est un réel fixe appartenant à un ouvert de R. Apres avoir défini les singularités d'ordre alpha de f(. ,t), on établit une expression maniable du processus de vraisemblance, et on applique les résultats obtenus à l'aide de cette expression d'un paramètre inconnu thêta
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Chen, Bo. "Partly exchangeable fragmentations." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:0e841fd3-51fa-4c72-be9f-08477e74d703.
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We introduce a simple tree growth process that gives rise to a new two-parameter family of discrete fragmentation trees that extends Ford's alpha model to multifurcating trees and includes the trees obtained by uniform sampling from Duquesne and Le Gall's stable continuum random tree. We call these new trees the alpha-gamma trees. In this thesis, we obtain their splitting rules, dislocation measures both in ranked order and in sized-biased order, and we study their limiting behaviour. We further extend the underlying exchangeable fragmentation processes of such trees into partly exchangeable fragmentation processes by weakening the exchangeability. We obtain the integral representations for the measures associated with partly exchangeable fragmentation processes and subordinator of the tagged fragments. We also embed the trees associated with such processes into continuum random trees and study their limiting behaviour. In the end, we generate a three-parameter family of partly exchangeable trees which contains the family of the alpha-gamma trees and another important two-parameter family based on Poisson-Dirichlet distributions.
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Hamonier, Julien. "Analyse par ondelettes du mouvement multifractionnaire stable linéaire." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2012. http://tel.archives-ouvertes.fr/tel-00753510.
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Le mouvement brownien fractionnaire (mbf) constitue un important outil de modélisation utilisé dans plusieurs domaines (biologie, économie, finance, géologie, hydrologie, télécommunications, etc.) ; toutefois, ce modèle ne parvient pas toujours à donner une description suffisamment fidèle de la réalité, à cause, entre autres, des deux limitations suivantes : d'une part le mbf est un processus gaussien, et d'autre part, sa rugosité locale (mesurée par un exposant de Hölder) reste la même tout le long de sa trajectoire, puisque cette rugosité est partout égale au paramètre de Hurst H qui est une constante. En vue d'y remédier, S. Stoev et M.S. Taqqu (2004 et 2005) ont introduit le mouvement multifractionnaire stable linéaire (mmsl) ; ce processus stochastique strictement α-stable (StαS), désigné par {Y(t)}, est obtenu en remplaçant la mesure brownienne par une mesure StαS et le paramètre de Hurst H par une fonction H(.) dépendant de t. On se place systématiquement dans le cas où cette fonction est continue et à valeurs dans l'intervalle ouvert ]1/α,1[. Il convient aussi de noter que l'on a pour tout t, Y(t)=X(t,H(t)), où {X(u,v)} est le champ stochastique StαS, tel que pour tout v fixé, le processus {X(u,v)} est un mouvement fractionnaire stable linéaire. L'objectif de la thèse est de mener une étude approfondie du mmsl, au moyen de méthodes d'ondelettes ; elle consiste principalement en trois parties. (1) On détermine de fins modules de continuité, globaux et locaux de {Y(t)} ; cela repose essentiellement sur une nouvelle représentation de {X(u,v)}, sous la forme d'une série aléatoire, dont on montre la convergence presque sûre dans certains espaces de Hölder. (2) On introduit, via la base de Haar, une autre représentation de {X(u,v)} en série aléatoire ; cette dernière permet la mise en place d'une méthode de simulation efficace du mmsl, ainsi que de ses parties hautes et basses fréquences. (3) On construit des estimateurs par ondelettes du paramètre fonctionnel H(.) du mmsl, ainsi que de son paramètre de stabilité α.
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Borghetti, Lorraine. "Neural Evidence for the Influence of Communication on Cognitive Processing as Proposed by Quantum Cognition Theory." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563492110175352.
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