Amostras de nitrato de potássio e enxofre natural foram irradiadas no núcleo do reator de pesquisas IEA-R1 do Instituto de Pesquisas Energéticas e Nucleares, IPEN/CNEN-SP, operando entre 3,5 e 5 MW de potência, para determinar as secções de choque térmicas e integrais de ressonância das reações 34S(n,)35S e 42K(n,)43K. O fluxo de nêutrons foi monitorado com ligas ouro-alumínio. As atividades induzidas nos alvos de ouro-alumínio e nitrato de potássio foram medidas com um detector semicondutor de germânio hiper puro; as atividades dos alvos de enxofre foram determinadas com um sistema de coincidências 4\\pi\\beta - \\gamma. Os efeitos de depressão de fluxo, autoblindagem e autoabsorção nos alvos foram corrigidos com base em simulações com o método de Monte Carlo por meio do programa MCNP. O programa PENELOPE, também baseado no método de Monte Carlo, foi modificado para simular o comportamento do sistema de coincidências 4\\pi\\beta - \\gamma. O formalismo de Westcott e o método da razão de cádmio foram usados para determinar os fluxos de nêutrons térmicos e epitérmicos, assim como as secções de choque térmicas e integrais de ressonância de ambos nuclídeos. Foi efetuado um tratamento estatístico das incertezas envolvidas e determinadas as covariâncias entre os resultados, incluindo aquelas decorrentes das incertezas do padrão de referência (ouro). As reações 34S(n,)35S e 42K(n,)43K apresentaram, respectivamente, seções de choque térmicas de 228(14) mb e 44,8(9) b, e integrais de ressonância de 144(6) mb e 1635(75) b. Estes resultados são incompatíveis com aqueles obtidos com cálculos teóricos. A seção de choque térmica da reação 34S(n,)35S concorda com valores obtidos por outros autores, dentro das incertezas experimentais. / Samples of potassium nitrate and natural sulphur were irradiated in the IPEN/CNEN-SP IEA-R1 research reactor core, operating between 3.5 and 5 MW, to determine the thermal neutron cross sections and resonance integrals of 34S(n,)35S and 42K(n,)43K reactions. The neutron flux was monitored with gold-aluminium alloy. The activities induced in targets of gold-aluminium and potassium nitrate were measured with a high purity germanium detector. Sulphur targets activities were determined with a 4\\pi\\beta-\\gamma coincidences system by the tracer method. Flux depression, self-shielding and self-absorption in the targets was evaluated by simulations using the MCNP software. The PENELOPE software, also based on Monte Carlo method, was modified to simulate the behavior of the 4\\pi\\beta-\\gamma coincidence system. The Westcott formalism and the cadmium ratio method were used to determine epithermal and thermal neutrons flux as well as the thermal cross sections and resonance integrals of both nuclides. A statistical analysis of the uncertainties was performed and the covariance between the results was determined, including those arising from the uncertainties of the gold reference standard. The results were compared with experimental values and theoretical predictions obtained by other authors. The 34S(n,)35S and 42K(n,)43K reactions had, respectively, thermal cross sections of 228(14) mb and 44.8(9) b, and integral resonances of 144(6) mb and 1635(75) b. These results are incompatible with the obtained with theoretical calculations. The 34S(n,)35S reaction thermal cross section agrees with values obtained by other authors, within the experimental uncertainties.

O Laboratório de Metrologia Nuclear (LMN) do Instituto de Pesquisas Energéticas e Nucleares (IPEN) realizou a padronização primária dos radionuclídeos 64Cu e 166Ho. Esses radioisótopos são utilizados na Medicina Nuclear em investigações diagnósticas e em radioterapia. A atividade absoluta foi determinada utilizando o método de coincidências 4πβ(PC)- γ associado à técnica de extrapolação de eficiência. Para isto, foram utilizados um contador proporcional em geometria 4π acoplado ao um contador de cintilação NaI (Tl). Para a padronização do 64Cu foram utilizados dois sistemas para registro de dados: sistema TAC e sistema SCS. No sistema TAC é utilizado o módulo Time to Amplitude Converter (TAC) associado a um analisador multicanal, sendo que a eficiência do detector 4πPC foi variada por meio de absorvedores externos e foi aplicado fator de correção para as eficiências beta denominado fator Kawada. No sistema SCS (Software Coincidence System) o registro dos eventos foi feito por meio da digitalização dos pulsos, a eficiência do detector 4πPC foi variada por discriminação eletrônica e a atividade foi obtida pela extrapolação biparamétrica. A padronização do 166Ho em sistema de coincidências 4πβ(PC)- γ foi realizada utilizando o sistema de aquisição de dados por software, SCS (Software Coincidence System). Para determinação das probabilidade de emissão gama dos radionuclídeos foi utilizado um espectrômetro gama HPGe calibrado com ampolas padrão de 152Eu, 60Co, 133Ba, 137Cs e 241Am, calibradas no sistema primário 4πβ(PC)- γ. A probabilidade de emissão gama por decaimento do fóton de 1345,7 keV do 64Cu obtida foi de 0,472 (10) % apresentando um bom acordo com os dados da literatura. A probabilidade de emissão gama por decaimento do fóton gama de 1379,45 keV do 166Ho foi de 0,936 (4) %. Por meio destas medidas foi possível também a determinação das intensidades relativas de outros fótons emitidos por este radionuclídeo. Os resultados obtidos foram concordantes com a literatura dentro da incerteza experimental. / The procedure followed by the Nuclear Metrology Laboratory (LMN) at the Nuclear and Energy Research Institute (IPEN) for the primary standardization of 64Cu and 166Ho is described. These radionuclides are widely applied to Nuclear Medicine such as in diagnostic investigations and in radiotherapy. The absolute activity of both radionuclides were determined by the efficiency extrapolation method applied to 4πβ(PC)-γ coincidence counting system using a proportional counter in 4π geometry coupled with NaI(Tl) scintillation counter. The primary standardisation of 64Cu for the conventional coincidence counting, the events were registered using a Time to Amplitude Converter (TAC) system associated with a multi-channel analyzer and by a software coincidence counting system, SCS, a digital method for primary activity measurements that simplifies the setting of optimal coincidence parameters. For perfoming the standardization of 64Cu in the TAC system, the efficiency of the 4πβ(PC)-γ detector was varied using external absorbers and in order to correct the beta efficiency, the Kawada factor was applied. In the SCS counting, the events were registered by means of pulse digitalization and the efficiencies (εEC and εβ) were varied through eletronic discrimination. The biparametric method was used for determining the absolute activity and the result was in good agreement with the ones obtained with TAC system. The standardization of 166Ho in the primary system was performed using the software coincidence counting, SCS. The gamma-ray emission probability per decay of the main transitions of both radionuclides were determined using the results obtained from the primary method, the 4πβ(PC)-γ coincidence system, associated with a calibrated HPGe gamma-ray spectrometer with standard ampoules of 152Eu, 60Co, 133Ba, 137Cs e 241Am, previously standardized in the 4πβ(PC)-γ system. The gamma-ray emission probability per decay of the 1345,7 keV transition of 64Cu was 0,472 (10) %, in good agreement with the literature. The gamma-ray emission probability per decay of the 1379,45 keV transition of 166Ho was 0,936 (4) %. It were also determined the relative gamma ray emmission probability of other gamma rays for this nuclide . All the results obtained were in good agreement with the literature.

Made available in DSpace on 2016-04-27T16:57:13Z (GMT). No. of bitstreams: 1 Carlos Eduardo de Campos.pdf: 1683164 bytes, checksum: 1dd97a1301e188ce53dd5d495c3b2f0e (MD5) Previous issue date: 2011-11-09 / Secretaria da Educação do Estado de São Paulo / This dissertation is focused on the teaching and learning of the Combinatorial Analysis, specifically mentioning, Counting Problems. The report is about a documentary research, as a result of the analysis of the coursebook, thus the methodological procedures are the most appropriate to this kind of investigation. The aim of this research is to evaluate the types of Counting Problems, which are included in the student s book, Secondary school second grade third term from the Department of Education of the state of São Paulo, in the view of the combinatorial research, taking into account that is the presupposition of the Curriculum of the state of São Paulo, the resolution of the problems in a teaching approach for the combinatorial concepts. The studied problems are the simple ones, in other words, those which could be solved by using only one combinatorial operation. The yardsticks of the content analysis accomplished in the book are the task variables used by Batanero, Navarro-Pelayo, implicit combinatorial model, combinatorial operation, the nature of the elements to be combined and the values of the parameter m and n. They are supported by the theory of the conceptual fields developed by Vergnaud, in which those concepts couldn t be learnt with the approach of a single type of problem. Our investigation led us to the conclusion that, even working with an important list of issues, many of them involved similar situations. It is because not all the considered variables were found in this list / Esta dissertação tem por foco o ensino e a aprendizagem da Análise Combinatória ou, mais especificamente, dos Problemas de Contagem. Trata-se do relatório minucioso de pesquisa documental de análise de material didático e, sobretudo, os procedimentos metodológicos são os adequados a essa modalidade de investigação. O objetivo da investigação é avaliar os tipos de Problemas de Contagem, que figuram no Caderno do Aluno do 3º bimestre do 2º ano do Ensino Médio, da Rede Estadual Paulista de Ensino, com vistas à formação do raciocínio combinatório, levando em conta o pressuposto da Proposta Curricular em questão que entende a resolução de problemas como uma abordagem de ensino eficaz para os conceitos combinatórios. Os problemas estudados são entendidos e classificados como simples, ou seja, aqueles que podem ser resolvidos usando somente uma operação combinatória. Os balizadores da análise de conteúdo realizada no Caderno são as variáveis de tarefa usadas por Batanero e Navarro-Pelayo: modelo combinatório implícito, operação combinatória, natureza dos elementos que se combinam e valores dados aos parâmetros m e n. Os mesmos são respaldados na Teoria dos Campos Conceituais de Verganaud, para a qual conceitos não podem ser apreendidos com a abordagem de um único tipo de problema. Nossa investigação nos levou a constatar que, mesmo com um elenco importante de problemas, muitos deles envolviam situações semelhantes. Isso se deu porque nem todas as variáveis consideradas foram encontradas nesse rol

Ce travail est centré sur la charactérisation de certaines classes de processus aléatoires par des formules de dualité. En particulier on considérera des processus réciproques à sauts, un cas jusqu'à présent négligé dans la littérature.Dans la première partie nous formulons de façon innovante une charactérisation des processus à accroissements indépendants. Celle-ci est basée sur une formule de dualité pour des processus infiniment divisibles, déjà connue dans le cadre du calcul de Malliavin. On va présenter deux nouvelles méthodes pour prouver cette formule, qui n'utilisent pas la décomposition en chaos de l'espace des fonctionnelles de carré intégrable. Une méthode s'appuie sur une formule d'intégration par parties satisfaite par des vecteurs aléatoires infiniment divisibles. Sous cet angle, notre charactérisation est une généralization du lemme de Stein dans le cas Gaussien et du lemme de Chen dans le cas Poissonien. La généralité de notre approche nous permet de plus, de présenter une charactérisation des mesures aléatoires infiniment divisibles.Dans la deuxième partie de notre travail nous nous concentrons sur l'étude des classes réciproques de processus de Markov avec ou sans sauts, et sur leur charactérisation. On commence avec un résumé des résultats déjà existants concernant les classes réciproques de diffusions browniennes comme solutions d'une formule de dualité. Nous obtenons notamment une nouvelle interprétation des classes réciproques comme les solutions d'une équation de Newton. Cela nous permet de relier nos résultats à la mécanique stochastique d'une part et à la théorie du contrôle optimale, d'autre part. La formule de dualité nous permet aussi de prouver une propriété d'invariance par retournement du temps de la classe réciproque d'une diffusion brownienne.En outre nous obtenons une série de nouveaux résultats concernant les processus de sauts purs. Nous décrivons d'abord la classe réciproque associée à un processus markovien de comptage, c'est-à-dire un processus de sauts de taille un, puis en présentons une charactérisation par une formule de dualité. Cette formule contient une dérivée stochastique, une intégrale stochastique compensée, et une fonctionnelle qui est une grandeur invariante de la classe réciproque. De plus nous livrons une interprétation de la classe réciproque comme ensemble des solutions d'un problème de contrôle optimal. Enfin, par une utilisation appropriée de la formule de dualité, nous montrons que la classe réciproque d'un processus markovien de comptage est invariante par retournement du temps.Quelques-uns de ces résultats restent valables pour des processus de sauts purs dont les sauts sont de taille variée. En particulier nous montrons que certaines fonctionnelles dites invariants réciproques permettent de distinguer différentes classes réciproques. Notre dernier résultat est la charactérisation de la classe réciproque d'un processus de Poisson composé dès lors que les (tailles des) différents sauts sont incommensurables. / This work is concerned with the characterization of certain classes of stochastic processes via duality formulae. In particular we consider reciprocal processes with jumps, a subject up to now neglected in the literature. In the first part we introduce a new formulation of a characterization of processes with independent increments. This characterization is based on a duality formula satisfied by processes with infinitely divisible increments, in particular Lévy processes, which is well known in Malliavin calculus. We obtain two new methods to prove this duality formula, which are not based on the chaos decomposition of the space of square-integrable functionals. One of these methods uses a formula of partial integration that characterizes infinitely divisible random vectors. In this context, our characterization is a generalization of Stein's lemma for Gaussian random variables and Chen's lemma for Poisson random variables. The generality of our approach permits us to derive a characterization of infinitely divisible random measures.The second part of this work focuses on the study of the reciprocal classes of Markov processes with and without jumps and their characterization. We start with a resume of already existing results concerning the reciprocal classes of Brownian diffusions as solutions of duality formulae. As a new contribution, we show that the duality formula satisfied by elements of the reciprocal class of a Brownian diffusion has a physical interpretation as a stochastic Newton equation of motion. Thus we are able to connect the results of characterizations via duality formulae with the theory of stochastic mechanics by our interpretation, and to stochastic optimal control theory by the mathematical approach. As an application we are able to prove an invariance property of the reciprocal class of a Brownian diffusion under time reversal.In the context of pure jump processes we derive the following new results. We describe the reciprocal classes of Markov counting processes, also called unit jump processes, and obtain a characterization of the associated reciprocal class via a duality formula. This formula contains as key terms a stochastic derivative, a compensated stochastic integral and an invariant of the reciprocal class. Moreover we present an interpretation of the characterization of a reciprocal class in the context of stochastic optimal control of unit jump processes. As a further application we show that the reciprocal class of a Markov counting process has an invariance property under time reversal. Some of these results are extendable to the setting of pure jump processes, that is, we admit different jump-sizes. In particular, we show that the reciprocal classes of Markov jump processes can be compared using reciprocal invariants. A characterization of the reciprocal class of compound Poisson processes via a duality formula is possible under the assumption that the jump-sizes of the process are incommensurable.

Os atuais avanços na área das Tecnologias da Informação e da Comunicação (TIC) estão mudando a Educação, com a disponibilização de sistemas educativos para apoiar as atividades no processo de ensino e de aprendizagem. Embora o tópico de combinatória seja relevante para o ensino médio e para os cursos de Ciências Exatas, este tópico tem sido desconsiderado nos avanços da Informática na Educação, principalmente ao se considerar o uso de ambientes de aprendizagem via Web. Atualmente, o iComb é, no melhor de nosso conhecimento, o único sistema Web integrável a tais ambientes. Ele é um Módulo de Aprendizagem Interativa (iMA) integrável ao Sistema Gerenciador de Cursos (SGC) Moodle, por meio do plugin iTarefa. O iComb oferece atividades de autoria de exercícios, bem como, sua avaliação automática. No entanto, considerando sua usabilidade, foram detectados alguns problemas na interface. O foco deste trabalho está relacionado ao reprojeto do sistema iComb e seu impacto na aprendizagem de combinatória. Para a reconstrução do iComb adotou-se o método de design de interação, buscando-se a participação efetiva de usuários finais do sistema, em todas as atividades desse processo, com (i) sessões de teste de usabilidade utilizando a versão Java do iComb para identificar problemas e guiar o redesenho do sistema, e (ii) prototipagem e avaliação da interface do sistema redesenhado. Esse processo permitiu implementar uma nova versão do iComb utilizando tecnologias associadas ao HTML5, que será brevemente disponibilizado como software livre. / Current advances in Information and Communication Technologies (ICT) are changing Education with delivering software to support learning/teaching activities. Although being relevant for Science, Technology, Engineering, and Mathematics (STEM) courses, Combinatorial Analysis is almost disregarded in these advances, mostly if we consider their integration with earning Management Systems. Currently, iComb is, at the best of our knowledge, the only system with such a possibility. It is an interactive Learning Module (iLM) that can be integrated to Moodle, through the iAssign plugin. iComb provides authoring activities as well as their automatic assessment. Nevertheless, considering the system usability, several interaction problems were detected during sessions with teachers and students. In this work it is described the process of redesigning the iComb system by adopting Interactive Design, to conduct controlled sessions of system use for (i) identifying usability issues for guiding the system redesign; and (ii) prototyping and evaluate the redesigned system interface, with end-users. This process allowed to implement new version of iComb using HTML5 related technologies that will be sooner available as free software, in order to reach a larger audience. Preliminary results on the interface evaluation indicate that both students and teachers felt more comfortable using the new interface of iComb and found it easier to execute common tasks.

No description available.

Cette thèse porte sur la théorie des modèles des structures pseudo-finies en mettant l’accent sur les groupes et les corps. Le but est d'approfondir notre compréhension des interactions entre les dimensions de comptage pseudo-finies et les propriétés algébriques de leurs structures sous-jacentes, ainsi que de la classification de certaines classes de structures en fonction de leurs dimensions. Notre approche se fait par l'étude d'exemples. Nous avons examiné trois classes de structures. La première est la classe des H-structures, qui sont des expansions génériques. Nous avons donné une construction explicite de H-structures pseudo-finies comme ultraproduits de structures finies. Le deuxième exemple est la classe des corps aux différences finis. Nous avons étudié les propriétés de la dimension pseudo-finie grossière de cette classe. Nous avons montré qu'elle est définissable et prend des valeurs entières, et nous avons trouvé un lien partiel entre cette dimension et le degré de transcendance transformelle. Le troisième exemple est la classe des groupes de permutations primitifs pseudo-finis. Nous avons généralisé le théorème classique de classification de Hrushovski pour les groupes stables de permutations d'un ensemble fortement minimal au cas où une dimension abstraite existe, cas qui inclut à la fois les rangs classiques de la théorie des modèles et les dimensions de comptage pseudo-finies. Dans cette thèse, nous avons aussi généralisé le théorème de Schlichting aux sous-groupes approximatifs, en utilisant une notion de commensurabilité / This thesis is about the model theory of pseudofinite structures with the focus on groups and fields. The aim is to deepen our understanding of how pseudofinite counting dimensions can interact with the algebraic properties of underlying structures and how we could classify certain classes of structures according to their counting dimensions. Our approach is by studying examples. We treat three classes of structures: The first one is the class of H-structures, which are generic expansions of existing structures. We give an explicit construction of pseudofinite H-structures as ultraproducts of finite structures. The second one is the class of finite difference fields. We study properties of coarse pseudofinite dimension in this class, show that it is definable and integer-valued and build a partial connection between this dimension and transformal transcendence degree. The third example is the class of pseudofinite primitive permutation groups. We generalise Hrushovski's classical classification theorem for stable permutation groups acting on a strongly minimal set to the case where there exists an abstract notion of dimension, which includes both the classical model theoretic ranks and pseudofinite counting dimensions. In this thesis, we also generalise Schlichting's theorem for groups to the case of approximate subgroups with a notion of commensurability

<p>This project investigates a laser radar system. The system is based on the principles of time-correlated single photon counting, and by measuring the times-of-flight of reflected photons it can find range profiles and perform three-dimensional imaging of scenes. Because of the photon counting technique the resolution and precision that the system can achieve is very high compared to analog systems. These properties make the system interesting for many military applications. For example, the system can be used to interrogate non-cooperative targets at a safe distance in order to gather intelligence. However, signal processing is needed in order to extract the information from the data acquired by the system. This project focuses on the analysis of different signal processing methods.</p><p>The Wiener filter and the Richardson-Lucy algorithm are used to deconvolve the data acquired by the photon counting system. In order to find the positions of potential targets different approaches of non-linear least squares methods are tested, as well as a more unconventional method called ESPRIT. The methods are evaluated based on their ability to resolve two targets separated by some known distance and the accuracy with which they calculate the position of a single target, as well as their robustness to noise and their computational burden.</p><p>Results show that fitting a curve made of a linear combination of asymmetric super-Gaussians to the data by a method of non-linear least squares manages to accurately resolve targets separated by 1.75 cm, which is the best result of all the methods tested. The accuracy for finding the position of a single target is similar between the methods but ESPRIT has a much faster computation time.</p>

The design of biomaterials, historically initiated and developed by physicians and engineers, in the last decades has slowly shifted toward a more biochemical based approach. For the replacement, repair and regeneration of tissues scientists are now focusing on materials that stimulate specific biological response at the molecular level. These biomaterials have already shown interesting applications in cell proliferation, differentiation, and extracellular matrix production and organization when the material modifications are designed to elicit specific interactions with cell integrins. In the present work we propose the application of this strategy for the development of blood-compatible materials. We first identified, in the coagulation cascade a key enzyme that constitute a valuable biological target for the development of anti-thrombogenic compounds. Piperazinyl-amide derivatives of N-alfa-(3-trifluoromethyl-benzenesulfonyl)-L-arginine were synthesized as graftable thrombin inhibitors. These inhibitors provided a spacer arm for surface grafting and a fluorine tag for XPS (X-ray photoelectron spectroscopy) detection. The possible disturbance of biological activity due to a variable spacer-arm fixed on the N-4 piperazinyl position was evaluated in vitro against human alfa-thrombin, in silico by molecular modelling and via X-ray diffraction study. Selected inhibitors, having inhibition potency in the mM range, were grafted on polyesters surface via wet chemistry and photochemical activation treatments. Wet chemistry surface grafting was performed by specific hydroxyl chain-ends activation and resulted in bioactive molecules fixation of 20-300pmol/cm2. The photochemical grafting was performed using a molecular clip providing an aromatic azide, for nitrene insertion into a polymer, and an activated ester for grafting of tag compounds. This grafting technique resulted in a dramatic increase in fixed bioactive signals (up to nmol/cm2). The material blood-compatibilization induced by the surface fixation of the inhibitors, was measured by a static blood clot weight measurement test. The wet chemistry grafting technique resulted in moderate blood-compatibilization while by the photochemical grafting method important decrease in surface blood clot formation was observed. In the latter case, the blood response to material contact was found to be strongly affected by the polyester surface photo-degradation induced by the activation treatment.

The design of biomaterials, historically initiated and developed by physicians and engineers, in the last decades has slowly shifted toward a more biochemical based approach. For the replacement, repair and regeneration of tissues scientists are now focusing on materials that stimulate specific biological response at the molecular level. These biomaterials have already shown interesting applications in cell proliferation, differentiation, and extracellular matrix production and organization when the material modifications are designed to elicit specific interactions with cell integrins. In the present work we propose the application of this strategy for the development of blood-compatible materials. We first identified, in the coagulation cascade a key enzyme that constitute a valuable biological target for the development of anti-thrombogenic compounds. Piperazinyl-amide derivatives of N-alfa-(3-trifluoromethyl-benzenesulfonyl)-L-arginine were synthesized as graftable thrombin inhibitors. These inhibitors provided a spacer arm for surface grafting and a fluorine tag for XPS (X-ray photoelectron spectroscopy) detection. The possible disturbance of biological activity due to a variable spacer-arm fixed on the N-4 piperazinyl position was evaluated in vitro against human alfa-thrombin, in silico by molecular modelling and via X-ray diffraction study. Selected inhibitors, having inhibition potency in the mM range, were grafted on polyesters surface via wet chemistry and photochemical activation treatments. Wet chemistry surface grafting was performed by specific hydroxyl chain-ends activation and resulted in bioactive molecules fixation of 20-300pmol/cm2. The photochemical grafting was performed using a molecular clip providing an aromatic azide, for nitrene insertion into a polymer, and an activated ester for grafting of tag compounds. This grafting technique resulted in a dramatic increase in fixed bioactive signals (up to nmol/cm2). The material blood-compatibilization induced by the surface fixation of the inhibitors, was measured by a static blood clot weight measurement test. The wet chemistry grafting technique resulted in moderate blood-compatibilization while by the photochemical grafting method important decrease in surface blood clot formation was observed. In the latter case, the blood response to material contact was found to be strongly affected by the polyester surface photo-degradation induced by the activation treatment.