Orientador: Otavio Augusto Vuolo Marques / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-03T17:18:28Z (GMT). No. of bitstreams: 1 Prado_LigiaPizzattodo_M.pdf: 5995494 bytes, checksum: b089a94ad3e332090eb62124620d5fb5 (MD5) Previous issue date: 2003 / Resumo: A reprodução de Liophis miliaris no Brasil foi estudada em quatro populações: Mata Atlântica do sul da Bahia, Mata Atlântica do litoral de São Paulo e Par_ Domínio Atlântico do interior de São Paulo e Domínio Atlântico do interior do Paraná. Em todas as localidades as fêmeas são maiores que os machos. Adultos e recém-nascidos da Mata Atlântica do sul da Bahia são menores que os das demais localidades. Nessa região, onde existe pouca variação climática ao longo do ano, as fêmeas apresentaram ciclo reprodutivo contínuo, ao passo que nas demais localidades ele é sazonal e relacionado ao aumento de temperatura e precipitação. O ciclo espermatogênico parece ser contínuo em todas as regiões. Nas populações onde o ciclo é sazonal, a cópula parece ocorrer antes da época de vitelogênese e, portanto, as fêmeas devem estocar os espermatozóides. A fecundidade é semelhante em todas as áreas e aumenta com o tamanho corporal da fêmea. A freqüência reprodutiva é menor na Mata Atlântica do sul da Bahia e, ao contrário das demais regiões, tende a ser maior em indivíduos de maior tamanho corporal. Os tipos de presas ingeridos são semelhantes nas quatro populações e fêmeas grávidas não se alimentam. Machos e fêmeas são parasitados (por nematóide Ophidiascaris sp. E cistacantos Oligacanthorynchus spira) em iguais proporções e os indivíduos da Mata Atlântica do sul da Bahia são menos parasitados. O parasitismo aparentemente não impede a reprodução da espécie. Entretanto, fêmeas parasitadas pelo nematóide, no Domínio Atlântico do interior do Paraná, apresentam menor fecundidade. A atividade das serpentes está relacionada ao ciclo reprodutivo e às variações climáticas nas quatro áreas estudadas. Liophis miliaris apresenta o ciclo reprodutivo diferente de outros membros da tribo Xenodontini, que tendem a se reproduzir continuamente mesmo em áreas onde a sazonalidade climática é acentuada. Assim, L. miliaris parece ser mais sensível a certos parâmetros ambientais do que outras espécies de Xenodontini já estudadas / Abstract: This work reports different aspects on reproduction of the colubrid snake Liophis miliaris in four different regions of Brazil: Atlantic forest in south Bahia state, coastal Atlantic forest in São Paulo Paraná states, inland Atlantic forest in São Paulo and inland Atlantic forest in Paraná. Females have larger snout-vent length (SVL) than males in all these regions. In south Bahia, where there is little climate variation, the reproductive cycle is continuous whereas in the other regions it is seasonal, related to warmer and more rainy season. Sperm production seems to occur all through the year in all these regions. Where reproductive cycle is seasonal, mating seems to be dissociated from vitellogenesis, thus, females must store sperm overwinter. Clutch size is similar in all populations increasing with maternal length. In the Atlantic forest in south Bahia newborn snakes had a smaller SVL than in the other regions studied. Reproductive frequency is lower in Atlantic forest in south Bahia, different from the other regions, tends to increase with female length. Prey items are similar in all populations and gravid females do not feed. Ophidiascaris sp. (Nematoda) and cystacanths of Oligacanthorynchus spira (Acanthocephala) were found equally in both females and males, fewer in snakes from Atlantic forest in Bahia. Apparently, these parasites do not impede reproduction, but females attacked by nematodes in the inland Atlantic forest in Paraná show a smaller clutch size than non-attacked ones. The activity pattern of adults snakes is associated with reproductive cycle and climate variation in all sites. The reproductive pattern of L. miliaris differs from other Xenodontini species which tend to reproduce continuously even in areas with seasonal climate. Thus, L. miliaris seems to be more sensitive to some climate variables than other studied species of Xenodontini / Mestrado / Mestre em Ecologia

Submitted by Biblioteca da Faculdade de Farmácia (bff@ndc.uff.br) on 2017-04-03T16:56:41Z No. of bitstreams: 1 Oliveira, Eduardo Coriolano de [Dissertação, 2011].pdf: 1135569 bytes, checksum: 8920e224ba454e60a5daa5d299a3e9bb (MD5) / Made available in DSpace on 2017-04-03T16:56:41Z (GMT). No. of bitstreams: 1 Oliveira, Eduardo Coriolano de [Dissertação, 2011].pdf: 1135569 bytes, checksum: 8920e224ba454e60a5daa5d299a3e9bb (MD5) / O envenenamento ofídico, dentre os acidentes com animais peçonhentos é o mais importante deles, pela sua frequência e gravidade. No Brasil, as serpentes do gênero Bothrops são responsáveis por 90 % dos acidentes ofídicos. Os extratos vegetais apresentam uma diversidade de moléculas com diversas ações farmacológicas. As espécies de Clusia são de grande interesse paisagístico, porém duas espécies deste gênero, C. torresii Standl. e C. palmana Standl. apresentam propriedades antiofídicas contra o veneno de B. asper. O objetivo do nosso trabalho foi avaliar as propriedades antiofídicas da espécie Clusia fluminensis Planch & Triana, utilizando diferentes partes vegetais e solventes de diferentes polaridades para o preparo dos extratos, assim como uma benzofenona isolada do extrato hexânico da flor, frente atividades biológicas do veneno de B. jararaca. Ensaios in vitro mostraram que os extratos hexânicos e metanólicos das folhas e frutos, na proporção de 1:50 (veneno:extrato) foram capazes de inibir 100 % a atividade proteolítica do veneno de B. jararaca (9 μg/mL), usando-se azocaseína como substrato; com exceção do extrato hexânico do caule e da benzofenona que inibiram cerca de 50 %. Na atividade hemolítica do veneno de B. jararaca (88 μg/mL), a inibição foi de 40 %, nas proporções de 1:10 e 1:20. Por outro lado, os extratos nestas mesmas proporções não foram capazes de neutralizar a coagulação do plasma induzida pelo veneno de B. jararaca (22 μg/mL), de forma significativa. Em ensaios in vivo (atividade hemorrágica) apenas o extrato acetônico do fruto, na proporção de 1:20, foi capaz de reverter totalmente a hemorragia causada pelo veneno de B. jararaca (16,7 μg/g). Sendo assim, nossos resultados mostram que a planta C. fluminensis pode ser uma fonte de moléculas com propriedades antiofídicas, especificamente contra o veneno de B. jararaca, e que este efeito neutralizante está diretamente relacionado a parte do vegetal e a polaridade do solvente utilizado na extração, Além disso podemos concluir que a benzofenona não é responsável, isoladamente, pelos resultados obtidos / Snake venom poisoning, among accidents with venomous animals is the most important of them, by their frequency and severity. In Brazil, Bothrops are responsible for 90 % of snake bites. The plant extracts have a variety of molecules with several pharmacological actions. Clusia species are of great landscape interest, but two species of this genus, C. torresii Standl. and C. palmana Standl. have properties against snake venom B. asper. The aim of our study was to evaluate the antivenom properties the species Clusia fluminensis Triana & Planch, using different plant parts and solvents of different polarities for the preparation of extracts, as well as a benzophenone isolated from the hexane extract of the flower, against biological activity of the venom of B. jararaca. In vitro assays showed that the hexane and methanolic extracts of leaves and fruits at a ratio of 1:50 (venom: extract) were able to inhibit 100 % proteolytic activity of the venom of B.jararaca (9μg/mL), using azocaseíne as substrate, with the exception of hexanic extract from stem and benzophenone which inhibited about 50 %. In the hemolytic activity of the venom of B. jararaca (88 μg/mL), inhibition was 40 %, the proportions of 1:10 and 1:20. On the other hand, the same proportions in these extracts were not able to neutralize the plasma coagulation induced by the venom of B. jararaca (22 μg/mL) significantly. In vivo assays (hemorrhagic activity) only the acetone extract of the fruit was able to totally reverse bleeding caused by the venom of B. jararaca (16,7 μg/g). Thus, our results show that the plant C. fluminensis can be a source of molecules with neutralizing properties of snake venom, specifically against the venom of B. jararaca, and that the neutralizing effect is directly related to part of the plant and the polarity of the solvent used in extraction, we can also conclude that benzophenone is not responsible alone for the results

Orientador : Lea Rodrigues Simioni / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-07-18T19:26:11Z (GMT). No. of bitstreams: 1 Goularte_FatimaCristianeLopes_M.pdf: 4007858 bytes, checksum: b4080ac0aab1511f58f42ca1d7d05cce (MD5) Previous issue date: 1993 / Resumo: O veneno de Micrurus nigrocinctus foi estudado in vitro sobre preparações neuromusculares isoladas de camundongo. À partir de tais experimentos e seus resultados, chegamos às seguintes conclusões: 1) o veneno de M. nigrocinctus induz importantes alterações miográficas, eletrofisiológicas e rnorfológicas sobre a preparação nervo frênico-diafragma de camundongo; 2) o bloqueio total da resposta contrátil do músculo diafragma mostra-se dose-dependente, e irreversível mediante a adição de droga anticolinesterásica e lavagens sucessivas da preparação; 3) A temperatura de incubação é um importante fator para o efeito bloqueador e miotóxico do veneno, sugerindo que uma PLA2 esteja envolvida nestes processos; 4) O soro anti- M. nigrocinctus é capaz de neutralizar in vitro a ação do veneno, tanto sobre a resposta muscular contrátil como sobre a miotoxicidade, mesmo quando for acrescentado após a adição do veneno; 5) As alterações ultraestruturais induzidas pelo veneno são acompanhadas por eleveção correspondente dos níveis de CK na solução do banho. Por outro lado, o aumento de CK é submaximal quando comparado com a liberação dessa enzima provocada pelo detergente Triton X-1OO; 6) A ocupação irreversível dos receptores pós-sinápticos pelo veneno parece ser a causa mais provável do bloqueio neuromuscular observado, pelo menos nas fases iniciais da intoxicação. Além disso, os resultados eletrofisiológicos e morfológicos também evidenciam uma ação pré-sináptica do veneno sobre a JNM, porém esta não seria a mais importante na gênese do bloqueio neuromuscular; 7) Embora tenha sido evidenciada urna ação do veneno sobre a JNM, como classicamente os venenos de serpentes corais são conhecidos, o presente estudo demonstrou que o veneno de M. nigrocinctus possui também um importante efeito miotóxico. Este efeito parece capaz de influenciar o desenvolvimento progressivo do bloqueio neuromuscular observado. / Abstract: In the isolated mouse diaphragrn, Micrurus nigrocinctus venom produces a dose-dependent blockade of the contractile response to electrical stimulation. This effect could not be reversed by repeated washing of the preparation or by the addition of an anticholinesterase. These observations suggest that, at least during the initial stages of poisoning, the mode of venom action involves binding of specific proteins to post-synaptic receptors. However, electrophysiological and morphological evidence suggests that the venom may also have a pre-synaptic action. Although the venom component responsible for this response has not yet been identified, the fact that the temperature at which the experiment was perforrned could greatly influence the neuromuscular blocking and myotoxic actions of the venom suggests that a neurotoxic PLA2 may be involved. Both the neuromuscular blocking action and the myotoxicity of the venom could be prevented by a specific M. Nigracinctus antivenam. This protective effect was maintained regardless af whether the antivenom was added before or after the venom. The muscle ultrastructural changes induced by the venom were accompanied by a corresponding increase in the release of creatine kinase into the incubation medium. This release was, however, submaximal when compared to that induced by the detergent Triton X-1OO. In conclusion, this work has demonstrated that, in addition to an action on the mammalian neuromuscular junction, M. Nigrocinctus venom also has. a pronounced myotoxic effect, which may well contribute to the progressive neuromuscular blockage seen with the venom. Both of the actions can effectively be prevented by a specific antivenom. / Mestrado / Mestre em Farmacologia

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The current study focuses on improving and testing the CTF thermalhydraulics computer code. CTF is a thermalhydraulic code used for subchannel analysis of nuclear power reactors developed as part of the US DOE CASL program and distributed by North Carolina State University. Subchannel analyses are used to predict the local fuel temperatures and coolant conditions inside a complex nuclear fuel assembly. Such calculations are used to improve designs of nuclear fuel, improve operating margins, or perform safety analysis. An important part of the code development process is the verification and validation for its intended use. In this work validation activities are performed using the RISO experiments are modeled in CTF for adiabatic and diabatic cases in annular flow regimes and a limited set of tests in CANDU geometries. The CTF predictions significantly overpredicted the pressure drop for cases involving annular flow conditions. Depending on the application, such overprediction can result in significant errors in the computation of fuel element dryout and other figures of merit. For example, an analysis using fixed pressure boundary conditions CTF predicts much lower subchannel flows and hence fuel element temperatures may be overestimated. On the other hand, for a scenario with mass flux and inlet pressure as boundary conditions, the impact of pressure drop discrepancies on dryout predictions may be lower. Therefore, there is a particular focus in this thesis on the two-phase pressure drop models and the RISO experiment specifically, since the RISO tests involve a range of annular flow conditions which is prototypical of many CANDU accident analysis conditions. In addition to the RISO experiments, 28-element CANDU full scale rod bundle experiments are modeled in CTF for single-phase and two-phase flow conditions. Cases are modeled for crept and uncrept conditions with different bearing pad heights i.e., 1.17 mm and 1.35mm. Pressure drop predictions are compared with the experimental results where single-phase comparisons are in good agreement while an overprediction of ~25% is observed for two-phase conditions. The effect of bearing pads on the subchannel local parameters, like mass flow rate, are also studied. Furthermore, the effect of turbulent mixing rate on subchannel enthalpy distribution in the bundle and CHF in different subchannels is also analyzed. Based on the comparison to the RISO and CANDU 28 element test databases, the overprediction of pressure drop in the annular flow regime needs improvement in the current version of CTF. This overprediction of the frictional pressure drop results from either wall drag or interfacial shear stress phenomena. In this study, it is demonstrated that the issue occurs mostly as a result of interfacial friction factor modelling this work examines several alternative approaches. The results show the Ju’s and Sun’s interfacial friction factor better predicts the results among all the other six correlations implemented in CTF. The major impediment in further testing of CTF is that it lacks the capability to simulate R-134a fluids. Given there is a large database of R-134a two-phase tests, another aspect of this thesis is to extend CTF for application and validation using refrigerants. The current CTF version only supports fluid properties for water and FLiBe salts. By adding R-134a fluid properties the testing and validation range of CTF is broadened for different experiments performed using R-134a fluids. CHF experiments are modeled in CTF and results are compared with experimental data. For local conditions correlation, 2006 water LUT are used to predict CHF and DNBR. The fluid-to-fluid scaling method is applied in CTF when using CTF with R-134a fluid properties for CHF and DNBR predictions to account for the difference in fluid properties between R-134a and the CHF look-up table. / Thesis / Master of Applied Science (MASc) / COBRA-TF (CTF) is a thermalhydraulic code, based on the historical code COBRA-TF, used for subchannel analysis of nuclear power reactors. Subchannel analysis can be used to predict the local fuel temperatures and coolant conditions inside a complex nuclear fuel assembly. CTF is a transient code that simultaneously solves conservation equations for mass, momentum, and energy for the three coolant phases present, i.e. vapor, continuous liquid, and entrained liquid droplet phases. The scope of the current study includes 1) testing the code for conditions relevant to CANDU accident analysis, 2) refinement of the models that are used in two-phase interfacial friction calculations, and 3) inclusion of alternate fluid properties. The testing of CTF is performed with different experimental databases covering CANDU thermalhydraulic conditions. The refinement is done by improving the pressure drop prediction in the annular flow regime by using different interfacial friction factor correlations from earlier studies in the literature. The current CTF version includes water and liquid salt properties (FLiBe) for coolant fluids. Freon (R-134a) fluid properties have been added in CTF in order to broaden the testing range of CTF for different experimental database using R-134a as working fluid.

Distributing functionality of an application is in common use. Systems that are built with this feature in mind also have to provide high levels of dependability. One way of assuring availability of services is to tolerate faults in the system, thereby avoiding failures. Building distributed applications is not an easy task. To provide fault tolerance is even harder. Using middlewares as mediators between hardware and operating systems on one hand and high-level applications on the other hand is a solution to the above difficult problems. It can help application writers by providing automatic generation of code supporting e.g. fault tolerance mechanisms, and by offering interoperability and language independence. For over twenty years, the research community is producing results in the area of . However, experimental studies of different platforms are performed mostly by using made-up simple applications. Also, especially in case of CORBA, there is no fault-tolerant middleware totally conforming to the standard, and well studied in terms of trade-offs. This thesis presents a fault-tolerant CORBA middleware built and evaluated using a realistic application running on top of it. Also, it contains results obtained after experiments with an alternative infrastructure implementing a robust fault-tolerant algorithm using basic CORBA. In the first infrastructure a problem is the existence of single points of failure. On the other hand, overheads and recovery times fall in acceptable ranges. When using the robust algorithm, the problem of single points of failure disappears. The problem here is the memory usage, and overhead values as well as recovery times that can become quite long. / <p>Report code: LiU-TEK-LIC-2002:55.</p>

Despite the association of the human gut microbiome and various diseases, a systematic definition of what constitutes a healthy human gut microbiome has not been established. This is crucial for microbiome research as it provides a basis for evaluating whether a given microbiome sample may deviate from the homeostasis state and is thus prone to the development of chronic diseases. This work aims to propose one such definition by using species/strain-resolved Genome-scale (GEM) models of metabolism. More specifically, we have constructed sample-specific GEMs from 30 healthy subjects using the taxonomic profiling of fecal metagenomic samples. We then computationally simulated these GEMs under a relevant diet (a supplemented typical Western diet) to determine which microbes in each sample contribute to the production of 17 key metabolites curated from literature and reported to be produced and secreted by the gut microbiota of healthy subjects. Beyond this pilot study, we plan to expand our analyses by creating samples-specific GEMs for a large-scale database of all publicly available metagenomic data from healthy subjects (~2,500 samples so far). We will additionally identify a core set of microbial species/strains that are necessary to perform all essential functions of a healthy microbiome. Taken together, this project offers a new paradigm to establish a healthy baseline microbiome definition by identifying generalized and personalized microbial blueprints that could serve as viable markers of health.

In recent years, in parallel with advances in computer technology, a multitude of computer tools have been developed through which it is possible to obtain a detailed description of the phenomena occurring in the core of nuclear reactors. The final ob-jective of these new tools is to perform safety analysis using best estimate techniques. The best estimate techniques, as opposed to the conservative ones, allow the operation of the reactor with narrower safety margins, and thus greater core economy. In this context, in this work is developed an multiphysics computer platform that inte-grates simulation codes that cover most of the physics that take place in nuclear reac-tors. For the integration of the different feedback phenomena between thermal-hydraulics, neutronics and heat transfer, a series of couplings have been developed between the codes that compose the platform. All the developments carried out are intended to realistically represent the design and behavior of the nuclear facility, in-cluding the control system, fuel elements and fuel rods. The computer platform includes some of the state-of-the-art codes for reactor analysis. The thermal-hydraulics is covered with a developed coupled code, consisting of the semi-implicit coupling between the TRACE system code and the subchannel code COBRA-TF (CTF), whose parallel version has been created in this work. In transients where three-dimensional neutron calculations are necessary, the explicit coupling be-tween the three-dimensional PARCS core simulator and the subchannel code CTF has been developed. For the analysis of the integrity of the fuel rods, the FRAPCON and FRAPTRAN codes are used, coupling the latter explicitly with CTF. All the developed tools have been included in the same computer platform that en-compasses and coordinates the simulations under the user's guidelines. The platform has enough flexibility to perform safety studies in a multitude of operational or acci-dental scenarios, and it is hoped that in the future it may be used for supporting li-cense calculations. The developed tools have been verified through a series of practical applications in different transient and accidental scenarios in light water reactors. The results obtained have been compared with actual plant measurements and with the results of other simulation codes showing adequate predictive capacity. The work carried out in this doctoral thesis is part of the research line financed by the Ministerio de Economía y Competitividad in the NUC-MULTPHYS project (ENE2012-34585) and the interdisciplinary collaboration projects of the Universitat Politècnica de Valencia COBRA_PAR (PAID-05-11-2810) and Open-NUC (PAID-05-12). / En los últimos años, paralelamente a los avances en tecnología informática, se están desarrollando multitud de herramientas informáticas mediante las que es posible obte-ner una descripción detallada de los fenómenos que tienen lugar en el núcleo de los reactores nucleares. El objeto de estas nuevas herramientas es el de realizar análisis de seguridad en reactores nucleares utilizando técnicas de mejor estimación. Las técnicas de mejor estimación, en contraposición con las conservadoras, permiten la operación del reactor con márgenes de seguridad más estrechos, y por tanto mayor economía del núcleo. En este contexto, en la presente tesis doctoral se desarrolla una plataforma informática que integra códigos informáticos que cubren la mayor parte de las físicas que tienen lugar en los reactores nucleares. Para la integración de los diferentes fenómenos de realimentación entre termohidráulica, neutrónica, mecánica y transmisión de calor se han desarrollado una serie de acoplamientos entre los códigos que componen la plata-forma. Todos los desarrollos realizados tienen por objetivo representar de forma rea-lista el diseño y comportamiento de la instalación nuclear, incluyendo el sistema de control, los elementos y las varillas de combustible. En la plataforma informática se incluyen algunos de los códigos de última generación (estado de arte) para el análisis del comportamiento de reactor. En el plano termohi-dráulico se utiliza el código acoplado desarrollado, formado por el acople semi-implícito entre el código de sistema TRACE y el de subcanal COBRA-TF (CTF), cuya versión paralela ha sido creada en este trabajo. En transitorios en los que resultan ne-cesarios los cálculos de neutrónica tridimensional, se ha desarrollado el acople explíci-to entre el simulador tridimensional de núcleos PARCS y el código de subcanal CTF. Para el análisis de la integridad de las varillas de combustible se emplean los códigos FRAPCON y FRAPTRAN, acoplando este último de forma temporalmente explícita con CTF. Todos los desarrollos realizados se han incluido en una misma plataforma informática que los engloba y coordina las simulaciones bajo las directrices del usuario. La plata-forma posee suficiente flexibilidad para realizar estudios de seguridad en multitud de escenarios operacionales o accidentales, y se desea que en un futuro pueda ser utilizada en cálculos de apoyo a licencia. Las herramientas desarrolladas han sido verificadas mediante una serie de aplicaciones prácticas en distintos transitorios y escenarios acci-dentales en reactores de agua ligera. Los resultados obtenidos se han comparado con medidas reales de planta y con los resultados de otros códigos de simulación mostran-do una adecuada capacidad predictiva. El trabajo realizado en la presente tesis doctoral se enmarca dentro de la línea de in-vestigación financiada por el Ministerio de Economía y Competitividad en el proyec-to NUC-MULTPHYS (ENE2012-34585) y los proyectos de colaboración interdisci-plinar de la Universitat Politècnica de Valencia COBRA_PAR (PAID-05-11-2810) y Open-NUC (PAID-05-12) / En els últims anys, paral·lelament als avanços en tecnologia informàtica, s'estan desenvolupant multitud de ferramentes informàtiques mitjançant les quals és possible obtindre una descripció detallada dels fenòmens que tenen lloc en el nucli dels reactors nuclears. L'objecte final d'aquestes noves ferramentes és el de realitzar anàlisis de segu-retat a reactors nuclears utilitzant tècniques de millor estimació. Les tècniques de mi-llor estimació, en contraposició amb les conservadores, permeten l'operació del reactor amb marges de seguretat més estrets, i per tant una major economia del nucli. En aquest context, en el present treball de tesi es desenvolupa una plataforma in-formàtica que integra codis informàtics que cobreixen la major part de les físiques que tenen lloc als reactors nuclears. Per a la integració dels diferents fenòmens de reali-mentació entre termohidràulica, neutrònica i transmissió de calor s'han desenvolupat una sèrie d'acoblaments entre els codis que componen la plataforma. Tots els desenvo-lupaments realitzats tenen per objectiu representar de forma realista el disseny i com-portament de la instal·lació nuclear, incloent el sistema de control, els elements i les varetes de combustible. A la plataforma informàtica s'inclouen alguns dels codis d'última generació (estat de l'art) per a l'anàlisi del comportament de reactor. En el pla termohidràulic s'utilitza el codi acoblat desenvolupat, format per l'acoblament semi-implícit entre el codi de sis-tema TRACE i el de subcanal COBRA-TF (CTF), en una versió paral·lela creada en aquest treball. En transitoris en els que resulten necessaris els càlculs de neutrònica tridimensional, s'ha desenvolupat l'acoblament explícit entre el simulador tridimensio-nal de nuclis PARCS i el codi de subcanal CTF. Per a l'anàlisi de la integritat de les varetes de combustible s'empren els codis FRAPCON i FRAPTRAN, acoblant aquest últim de forma temporalment explícita amb CTF. Tots els desenvolupaments realitzats s'han inclòs en una mateixa plataforma informàti-ca que els engloba i coordina les simulacions sota les directrius de l'usuari. La plata-forma posseeix suficient flexibilitat per realitzar estudis de seguretat en multitud d'es-cenaris operacionals o accidentals, i es desitja que en un futur pugui ser utilitzada en càlculs de suport a llicència. Les ferramentes desenvolupades han sigut verificades mitjançant una sèrie d'aplicacions pràctiques en diferents transitoris i escenaris acci-dentals en reactors d'aigua lleugera. Els resultats obtinguts s'han comparat amb mesu-res reals de planta i amb els resultats obtinguts amb altres codis de simulació, mostrant una adequada capacitat predictiva. El treball realitzat en la present tesi doctoral s'emmarca dins de la línia d'investigació finançada pel Ministeri d'Economia i Competitivitat en el projecte NUC-MULTPHYS (ENE2012-34585) i els projectes de col·laboració interdisciplinar de la Universitat Politècnica de València COBRA_PAR (PAID-2810.11.05) i Open-NUC (PAID-05-12). / Abarca Giménez, A. (2017). Desarrollo y verificación de una plataforma multifísica de altas prestaciones para análisis de seguridad en ingeniería nuclear [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/88399

Yes / E-government services involve many stakeholders who have different objectives that can have an impact on success. Among these stakeholders, citizens are the primary stakeholders of government activities. Accordingly, their satisfaction plays an important role in e-government success. Although several models have been proposed to assess the success of e-government services through measuring users' satisfaction levels, they fail to provide a comprehensive evaluation model. This study provides an insight and critical analysis of the extant literature to identify the most critical factors and their manifested variables for user satisfaction in the provision of e-government services. The various manifested variables are then grouped into a new quantitative analysis framework consisting of four main constructs: cost; benefit; risk and opportunity (COBRA) by analogy to the well-known SWOT qualitative analysis framework. The COBRA measurement scale is developed, tested, refined and validated on a sample group of e-government service users in Turkey. A structured equation model is used to establish relationships among the identified constructs, associated variables and users' satisfaction. The results confirm that COBRA framework is a useful approach for evaluating the success of e-government services from citizens' perspective and it can be generalised to other perspectives and measurement contexts. / (PIAP-GA-2008-230658) from the European Union Framework Program7 and another grant (NPRP 09-1023-5-158) from the Qatar National Research Fund (a member of Qatar Foundation)