Made available in DSpace on 2014-06-12T15:52:52Z (GMT). No. of bitstreams: 2 arquivo4786_1.pdf: 1721462 bytes, checksum: cd3726fecb794776ca337a60470ce4f1 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 204 / O comportamento do tráfego das redes atuais é caótico, possuindo propriedades estatísticas que incluem correlações temporais complexas. Neste cenário, um problema ainda não resolvido é o do congestionamento do tráfego. É um problema atual que tem sido agravado com o crescimento do uso de aplicações multimídia de tempo real com requisitos estritos de atraso. Apesar do aumento das taxas de transmissão dos canais de longa distância, o problema do congestionamento ainda persiste, sobretudo nas redes de acesso. A natureza não estacionária do tráfego das redes, as dependências temporais de curto e de longo alcance e os ruídos presentes no tráfego tornam difícil a tarefa de se fazer previsão de congestionamentos. Os benefícios de se prever possíveis congestionamentos em um tempo futuro curto (na ordem de milissegundos) são relevantes para os mecanismos de controle de congestionamento das atuais redes, pois evita o desperdício de recursos através de medidas de controle que vão desde o descarte de pacotes até o provisionamento de largura de banda adicional nos canais, passando pela limitação da taxa de entrada de pacotes na rede. Este trabalho propõe e implementa o mecanismo ProCon para identificar situações que podem causar congestionamentos em redes de computadores. O método usado para alcançar tal objetivo é a transformação de séries de tempo que representam o tráfego real nas redes para identificar a componente de tendência das mesmas. A idéia é utilizar wavelets, ou seja, ao invés de prever o comportamento do tráfego diretamente no domínio do tempo, modelamse as propriedades estatísticas da série no domínio wavelet e, em seguida, utilizam-se técnicas de estimação de tendências para indicar possíveis casos de congestionamento. O mecanismo proposto produziu o efeito desejado, pois detectou possíveis casos de congestionamento

Doctor en Bioquímica / Autorizada por el autor, pero con restricción para ser publicada a texto completo hasta diciembre de 2015, en el Portal de Tesis Electrónicas / El péptido similar a glucagón-1 (GLP-1) es una incretina secretada por las células intestinales. Su acción clásica es regular la respuesta secretoria de insulina por el páncreas. Sin embargo, recientemente se ha descrito que GLP-1 posee acciones extrapancreáticas muy similares a la insulina, con mecanismos de señalización tejido-específicos. Por sus muchas acciones fisiológicas, y la mayoría relacionadas con los efectos insulinotrópicos de esta incretina, derivados peptidomiméticos de GLP-1 se utilizan actualmente para controlar la hiperglicemia en individuos con diabetes mellitus tipo 2. Debido a esto se hace muy interesante investigar su acción específica sobre distintos tipos celulares que sufren alteraciones en patologías relacionadas con alteraciones metabólicas asociadas a la diabetes mellitus. En particular, se hace muy interesante estudiar el efecto de GLP-1 sobre las células vasculares musculares lisas (VSMC). Estas células responden a variadas señales ambientales fisiopatológicas o bioquímicas, regulando su función y su fenotipo. Sin embargo, aún no se comprende la totalidad de mecanismos involucrados en los cambios fenotípicos que ocurren en estas células en patologías como la diabetes. Evidencias recientes han involucrado a las alteraciones metabólicas que sufren las VSMC con la mayor incidencia de aterosclerosis en pacientes diabéticos. Las mitocondrias son los principales organelos asociados con el control del metabolismo energético dentro de una célula. Actualmente, se sabe que procesos subcelulares tales como la interacción mitocondria-retículo endoplásmico y los fenómenos de fusión y fisión mitocondrial, conocido como dinámica mitocondrial, son capaces de regular la función y el metabolismo mitocondrial. La dinámica mitocondrial está finamente regulada por las proteínas Mitofusinas 1/2 y OPA-1 para el caso del proceso de fusión, y Drp-1 y Fis-1 para el caso del proceso de fisión mitocondrial. Se ha descrito un papel trascendental para la proteína Drp-1 en la regulación del proceso de fisión, ya que puede sufrir modificaciones postraduccionales que modulan su interacción con la mitocondria generando cambios en el proceso de fisión. Dentro de las modificaciones postraduccionales de Drp-1 se destaca una fosforilación inhibitoria por PKA. Debido a que el receptor clásico de GLP-1 es una proteína de siete dominios de transmembrana acoplada a proteína Gs, la activación por GLP-1 de este receptor aumentaría los niveles intracelulares de cAMP activando PKA, pudiendo regular potencialmente el proceso de fisión mitocondrial vía Drp-1. Esta regulación podría ser un nuevo mecanismo por el cual GLP-1 podría regular, vía el control de la dinámica, el metabolismo mitocondrial y por ende el metabolismo celular. Con todos estos antecedentes se propuso como hipótesis que GLP 1 inhibe el proceso de fisión mitocondrial, incrementando el metabolismo mitocondrial a través de la fosforilación de Drp 1, en células de la línea A7r5. Para probar esta hipótesis, células A7r5 correspondientes a células embrionarias de VSMC de aorta de rata se trataron con GLP-1 (100 nM) por 0 – 24 h y se incubaron con la sonda Mitotracker Orange en los últimos 30 min de exposición a la hormona. Posteriormente, las células se visualizaron en un microscopio confocal, la red mitocondrial se reconstruyó tridimensionalmente a partir de las imágenes obtenidas, determinándose el número, volumen promedio y área promedio de las mitocondrias. Los resultados muestran que GLP-1 inhibió el proceso de fisión de la red mitocondrial a las 3 h de tratamiento, lo cual se evidenció por un aumento del volumen y el área mitocondrial promedio. Además, en estas condiciones, los niveles de la proteína constitutiva mitocondrial mtHsp70 no se modificaron en relación a los controles, descartando que GLP-1 induzca biogénesis mitocondrial. El metabolismo mitocondrial se evaluó mediante la determinación de potencial de membrana mitocondrial, usando la sonda JC1; producción de especies reactivas de oxígeno (ROS), usando la sonda dihidrocloro fluoresceína; niveles intracelulares de ATP, usando lucifenina/luciferasa; y tasa de respiración, medido por oxigrafía. GLP-1 (100 nM) aumentó el potencial de la membrana mitocondrial, los niveles de ROS, los niveles intracelulares de ATP y el consumo de oxígeno. Se demostró que en células A7r5, GLP-1 activa a la vía transduccional dependiente de PKA. Además, mediante inmunoprecipitación de Drp-1 y posterior detección de la fosforilación de Drp-1 por Western blot se determinó que GLP-1 induce la fosforilación de Drp-1 de una manera similar a la inducida por forskolina. Además, mediante inmunofluorecencia se observó que GLP-1 previene la translocación de Drp-1 a la mitocondria. Utilizando H-89, un inhibidor específico de PKA, se demostró que la inhibición del proceso de fisión mitocondrial es dependiente de la activación de PKA. Posteriormente, se analizó la dependencia de la vía PKA para la acción de GLP-1 sobre el metabolismo mitocondrial. H-89 revertió el efecto de GLP-1 sobre el potencial de membrana mitocondrial y el incremento de los niveles de ROS. En resumen, los datos obtenidos permite sugerir que GLP-1 aumenta el metabolismo mitocondrial en las células A7r5 por un mecanismo que involucra la inhibición del proceso de fisión mitocondrial y la fosforilación de Drp-1 a través de una vía transduccional dependiente de PKA / Glucagon like peptide-1 (GLP-1) is an incretin hormone secreted by intestinal cells. Its classical action is to regulate insulin secretion in the pancreas. However, recently extrapancreatic insulinotropic actions of GLP-1 were described involving tissue-specific signaling pathways. Because GLP-1 have a variety of physiological actions mainly related with its insulinotropic actions, currently GLP-1 peptide mimetics are used to treat hyperglycemia in diabetes mellitus type 2 patients. For this reason, GLP-1 actions on different cell types that undergo pathological metabolic alterations related with diabetes mellitus are very interesting to explore. Particularly, we have focused on GLP-1 effects on vascular smooth muscle cells (VSMC). These cells can regulate both function and phenotype depending on biochemical and physiopathological environmental signals. However, mechanisms involved in VSMC phenotypic change in diseases such as diabetes are just beginning to be understood. Recent evidences have associated the existence of metabolic alterations in VSMC with an increase of atherosclerosis in diabetic patients. Mitochondria are the main organelle that controls energetic metabolism within cells. Specifically, subcellular events such as the interaction between mitochondria and endoplasmic reticulum and mitochondrial fusion and fission (i.e. mitochondrial dynamics) regulate mitochondrial function and metabolism. Mitochondrial dynamics is regulated by proteins, Mitofusins 1/2 and OPA-1 control fusion, and Drp-1 and Fis-1 control fission. Drp-1 has an important role in fission control, because it can be post-translationally modified, changing its interaction with mitochondria and affecting the mitochondrial fission rate. The most important post-translational modification is an inhibitory phosphorylation by PKA. The classical GLP-1 receptor (GLP-1R) is a seven transmembrane Gs-protein coupled receptor, and its activation causes an increase of cAMP levels activating PKA. Because this PKA activations GLP-1R could potentially regulates mitochondrial fission by Drp-1 phosphorylation. This regulation could be a novel GLP-1-dependent mechanism to control mitochondrial dynamics, mitochondrial metabolism and cellular metabolism. Consequently, we hypothesized that GLP-1 decreases mitochondrial fission and increases metabolism through Drp-1 phosphorylation in the A7r5 cell line. To test this hypothesis, A7r5 cells (rat embryonary aortic VSMC) were exposed to GLP-1 (100 nM) for 0 – 24 h and incubated with Mitotracker Orange dye in the last 30 min of “the hormone treatment”. Later, cells were observed under confocal microscope, mitochondrial network was reconstructed from images obtained, and number, average volume and area were determined. Our findings showed that GLP-1 decreased mitochondrial fission at 3 h, evidenced by the increase in mitochondrial volume average and area. These events did not affect mitochondrial constitutive mtHsp70 protein levels, discarding mitochondrial biogenesis induced by GLP-1. Mitochondrial metabolism was evaluated by measuring mitochondrial membrane potential, using JC1 dye; reactive oxygen species (ROS), by dihydrochloro fluorescein dye; intracellular ATP level, using luciferin/luciferase; and respiration rate, by oxygraphy. GLP-1 (100 nM) increased mitochondrial membrane potential, ROS levels, ATP content and oxygen consumption. We demonstrated that GLP-1 activates PKA signaling pathway in A7r5 cells. Moreover, through Drp-1 immunoprecipitation and phospho-Drp-1 detection by Western blot, we showed that GLP-1, as well as forskolin, induced Drp-1 phosphorylation. Consequently, Drp-1 translocation to the mitochondria was prevented by GLP-1, as determined by immunofluorescence. Using the PKA specific inhibitor, H-89, it was demonstrated that GLP-1 decreased mitochondrial fission depends on PKA activation. Subsequently, PKA dependence on GLP-1-induced mitochondrial metabolism was explored. We determined that H-89 prevented GLP-1 effects on both mitochondrial membrane potential and ROS production. In summary, our data suggest that GLP-1 increases mitochondrial metabolism in A7r5 cells by a mechanism involving mitochondrial fission and Drp-1 phosphorylation through a PKA-dependent signaling pathway / FONDECYT FONDAP ANILLO ACT1111

In [DS1,2,3], Denker and Sato initiated a new point of view to study the problem. They identified the Sierpinski gasket as a Martin boundary of some canonical Markov chain and used the associated theory to consider the problem. In this thesis, we will extend their result so as to be applicable to all single-point connected monocyclic post critically finite (m.p.c.f.) self-similar sets. / In the first chapter, we review some basic facts of the self-similar sets and the Martin boundaries, and we prove that every m.p.c.f. self-similar set K is homeomorphic to the quotient space of the symbolic space associated with K, moreover, the homeomorphism is a Lipschitz equivalence for some special m.p.c.f. self-similar sets. / In the second chapter, we first prove that the quotient space of the symbolic space associated with K is homeomorphic to the Martin boundary with respect to the state space associated with K if K is a single-point connected m.p.c.f. self-similar set. Combining this result and the result in the first chapter, we conclude that every single-point connected m.p.c.f. self-similar set can be identified with the Martin boundary of some canonical Markov chain. Then for the 3-level Sierpinski gasket, we prove that there exists a one to one relation between the strongly P-harmonic functions on the 3 state space and K-harmonic functions constructed by Kigami. / In the third chapter, we define a new Markov chain on the pentagasket K which is a single-point connected m.p.c.f. self-similar also. Under the new Markov chain, we prove that K can be identified with the Martin boundary of the new Markov chain and that there exists a one to one relation between the strongly P-harmonic functions and the K-harmonic functions. / One of the fundamental problems in fractal analysis is to construct a Laplacian on fractals. Since fractals, like the Sierpinski gasket and the pentagasket, do not have any smooth structures, it is not possible to construct it from the classical point of view. Hence, until now there is no systematic way to define such a notion on the general class of fractals. / There are two approaches for the problem which have achieved some success in certain special situations. The first one is a probabilistic approach via constructing Brownian motions on self-similar sets. The second approach is an analytical one proposed by Kigami. He approximated the underlying self-similar set K by an increasing sequence of finite sets equipped with the discrete Laplacians Hm in a consistent way. He showed that if K is strongly symmetric, then Hm converge to a Laplacian on K. / by Ju, Hongbing. / "March 2008." / Adviser: Lau Ka Sing. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1702. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 91-94). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

The class of groups generated by automata have been a source of many counterexamples in group theory. At the same time it is connected to other branches of mathematics, such as analysis, holomorphic dynamics, combinatorics, etc. A question that naturally arises is finding the ways to classify these groups. The task of a complete classification and understanding at the moment seems to be too ambitious, but it is reasonable to concentrate on some smaller subclasses of this class. One approach is to consider groups generated by small automata: the automata with k states over d-letter alphabet (so called, (k,d)-automata) with small values of k and d. Certain steps in this directions have been made already: All groups generated by (2,2)-automata have been classified, and groups generated by (3,2)-automata were studied. In this work we study the class of groups generated by (4,2)-automata. More specifically, we partition all such automata into equivalence classes up to symmetry and minimal symmetry (symmetric and minimally symmetric automata naturally generate isomorphic groups) and classify completely all finite groups generated by automata in this class. We also list all classes generating abelian groups. Another important result of the project is developing a database of (4,2)-automata and computational routines that represent a new effective tool for the search for (4,2)-automata generating groups with specific properties, which hopefully will lead to finding counterexamples of certain conjectures.

Burgers’ Equation ut + cuux = νuxx is a nonlinear partial differential equation which arises in models of traffic and fluid flow. It is perhaps the simplest equation describing waves under the influence of diffusion. We consider the large time behavior of solutions with exponentially localized initial conditions, analyzing the rate of convergence to a known self similar single-hump solution. We use the Cole-Hopf Transformation to convert the problem into a heat equation problem with exponentially localized initial conditions. The solution to this problem converges to a Gaussian. We then find an optimal Gaussian approximation which is accurate to order t−2. Transforming back to Burgers’ Equation yields a solution accurate to order t−2.

This dissertation is devoted to the measure theoretical aspects of the theory of automata and groups generated by them. It consists of two main parts. In the first part we study the action of automata on Bernoulli measures. We describe how a finite-state automorphism of a regular rooted tree changes the Bernoulli measure on the boundary of the tree. It turns out, that a finite-state automorphism of polynomial growth, as defined by Sidki, preserves a measure class of a Bernoulli measure, and we write down the explicit formula for its Radon-Nikodim derivative. On the other hand the image of the Bernoulli measure under the action of a strongly connected finite-state automorphism is singular to the measure itself. The second part is devoted to introduction of measure into the theory of limit spaces of Nekrashevysh. Let G be a group and φ : H → G be a contracting homomorphism from a subgroup H < G of finite index. Nekrashevych associated with the pair (G, φ) the limit dynamical system (JG, s) and the limit G-space XG together with the covering ∪g∈GT · g by the tile T. We develop the theory of selfsimilar measures m on these limit spaces. It is shown that (JG, s,m) is conjugate to the one-sided Bernoulli shift. Using sofic subshifts we prove that the tile T has integer measure and we give an algorithmic way to compute it. In addition we give an algorithm to find the measure of the intersection of tiles T ∩ (T · g) for g ∈ G. We present applications to the evaluation of the Lebesgue measure of integral self-affine tiles. Previously the main tools in the theory of self-similar fractals were tools from measure theory and analysis. The methods developed in this disseration provide a new way to investigate self-similar and self-affine fractals, using combinatorics and group theory.

Let μ be a Radon probability measure on M, the d-dimensional Real Euclidean space (where d is a positive integer), and f a measurable function. Let P be the space of sequences whose coordinates are elements in M. Then, for any point x in M, define a function ƒn on M and P that looks at the first n terms of an element of P and evaluates f at the first of those n terms that minimizes the distance to x in M. The measures for which such sequences converge in measure to f for almost every sequence are called Mycielski-regular. We show that the self-similar measure generated by a finite family of contracting similitudes and which up to a constant is the Hausdorff measure in its dimension on an invariant set C is Mycielski-regular.

Utifrån ett elevperspektiv har syftet med examensarbetet varit att ta reda på vilka strategier eleverna använder sig av när de har två språk, modersmålet danska och andraspråket svenska, som är så lika och ändå så olika, för att uppnå ett bättre lärande. Med hjälp av frågeställningarna Vilka lingvistiska strategier använder de sig av när svenska språket skal översättas till danska?, Vilka problem kan det uppstå när det svenska språket skall översättas till modersmålet danska?, Hur kan kunskaper om det ena språket hjälpa till när de ska översätta till ett andra? redovisas en kontrastivt empirisk undersökning för att få svar på dessa. I forskningen anses elevernas språkliga medvetenhet att ha stor vikt för elevernas språkförmåga. För att uppnå språkligt medvetenhet ska det i viss mån både tas hänsyn till deras kognitiva, sociala och affektiva aspekter samtidigt med att de själva är engagerade och tar ansvar i sitt lärande. Tillika krävs det att läraren undervisar utifrån didaktiska metoder som kan utveckla och stötta eleverna i sina språk. I den empiriska delen redovisas intervjusvar från 6 elever från klass 7-9 utifrån en översättning av en svensk text om till dansk. Undersökningen visar at eleverna är semantisk medvetna i de två språkens likheter och skillnader. Eleverna använder sig av strategier där de fokusera på språken – deras likheter och olikheter i fonologin, morfologin, reglarna i grammatik och syntax. De upptäcker och verbaliserar de grammatiska reglerna, de ljudar och rättar sig själva . De använder sig av sina erfarenheter utifrån sina egna upplevelser och de sätter sig in i hur en dansk vän eller väninna hade uttryckt sig så att meningarna låter rätt på danska. Samtidig är de uppmärksamma på att läraren kan vara med om att underlätta deras utveckling, så att de blir språkligt medvetna, och att det handlar om att undervisa med metoder så att eleverna har lust att lära och som kan styrka deras tankeprocesser och kunskaper.

Le jaune d’œuf est une source de nutriments et de molécules bioactives pour l’embryon. Il renferme de nombreuses protéases et antiprotéases, dont la fonction reste méconnue. Notre objectif était d’identifier et de caractériser les protéases/antiprotéases associées spécifiquement à la formation du jaune d’œuf (vitellogénèse). Les précurseurs du jaune sont exprimés par le foie à la maturité sexuelle des poules. Par une approche transcriptomique, nous avons identifié 582 gènes, dont 15 protéases et antiprotéases, sur exprimés par le foie des poules sexuellement matures. Au moins trois d’entre elles sont présentes dans le jaune ou la membrane vitelline. Nous avons montré que l’expression de la « similar to nothepsin », une protéase prédite de fonction inconnue, était spécifique du foie des femelles et pourrait participer à la maturation des précurseurs du jaune. D’autre part, nous avons démontré que l’ovoinhibiteur, une antiprotéase du jaune, aurait un rôle dans la défense antimicrobienne de l’œuf. L’intégration de l’ensemble de ces résultats fournira des données essentielles relatives à la vitellogénèse et à la fonction des protéases/antiprotéases dans le jaune d’œuf. / The egg yolk is a source of nutrients and bioactive molecules for the embryo,including many proteases/antiproteases, the function of which is still unknown. Our objective was to identify and characterize proteases/ antiproteases that are specifically associated with the formation of the yolk (vitellogenesis). Yolk precursors are synthesized by the liver at sexual maturity of hens. Using a transcriptomic approach, we identified 582 genes, including15 proteases and antiproteases that are over-expressed by the liver at sexual maturity of hens. At least three of them are recovered in the egg yolk or the vitelline membrane. We have shown that the expression of "similar to nothepsin” was specific to the liver of females. This protease could participate in the processing of yolk precursors. We have also demonstrated that egg yolk ovoinhibitor is antimicrobial and could therefore participate in egg defense. The integration of all these results will provide major data relative to vitellogenesis and to the function of proteases/antiproteases in the egg yolk.

In this dissertation, we address the statistical analysis under the multiscale framework for the self-similar process. Motivated by the problems arising from geophysics and health informatics, we develop a set of statistical measures as discriminative summaries of the self-similar process. These measures include Multiscale Schur Monotone (MSM) measures, Geometric Attributes of Multifractal Spectrum (GAMFS), Quasi-Hurst exponents, Mallat Model and Tsallis Maxent Model. These measures are used as methods to quantify the difference (or similarities) or as input (feature) vectors in the classification model. As the cornstone of GAMFS, we study the estimation of multifractal spectrum and adopt a Weighted Least Squares (WLS) schemes in the wavelet domain to minimize the heteroskedastic effects , which is inherent because the sample variances of the wavelet coefficients depend on the scale. We also propose a Combined K-Nearest-Neighbor classifier (Comb-K-NN) to address the inhomogeneity of the class attributes, which is indicated by the large variations between subsets of input vectors. The Comb-K-NN classifier stabilizes the variations in the sense of reducing the misclassification rates. Bayesian justifications of Comb-K-NN classifier are provided. GAMFS, Quasi-Hurst exponents, Mallat Model and Tsallis Maxent Model are used in the study of assessing the effects of atmospheric stability on the turbulence measurements in the inertial subrange. We also formulate the criteria for success in evaluating how atmospheric stability alters the MFS of a single flow variable time series as a statistical classification model. We use the multifractal discriminate model as the solution of this problem. Also, high frequency pupil-diameter dynamic measurements, which are well documented as measures of mental workload, are summarized using both GAMFS and MSM. These summaries are further used as the feature vector in the Comb-K-NN classifier. The serious inhomogeneity among subjects in the same user group makes classification difficult. These difficulties are overcome by using Comb-K-NN classifier.