Germanium content in marine sediments

In the geosphere, germanium (Ge) has a chemical behavior close to that of silicon (Si), and Ge commonly substitutes for Si (in small proportions) in silicates. Studying the evolution of the respective proportions of Ge and Si through time allows us to better constrain the global Si cycle. The marine inventory of Ge present as dissolved germanic acid is facing two main sinks known through the study of present sediments: 1) incorporation into diatom frustules and transfer to sediments by these "shuttles", 2) capture of Ge released to pore water through frustule dissolution by authigenic mineral phases forming within reducing sediments. Our goals are to determine whether such a bio-induced transfer of Ge is also achieved by radiolarian and whether Ge could be trapped directly from seawater into authigenic phases with no intervention of opal-secreting organisms (shuttles). To this end, we studied two Paleozoic radiolarite formations and geological formations dated of Devonian, Jurassic and Cretaceous, deposited under more or less drastic redox conditions. Our results show that the Ge/Si values observed for these radiolarites are close to (slightly above) those measured from modern diatoms and sponges. In addition, our results confirm what is observed with some present-day reducing sediments: the ancient sediments that underwent reducing depositional conditions are authigenically enriched in Ge. Furthermore, it is probable that at least a part of the authigenic Ge came directly from seawater. The recurrence and extent (through time and space) of anoxic conditions affecting sea bottoms have been quite important through the geological times; consequently, the capture of Ge by reducing sediments must have impacted Ge distribution and in turn, the evolution of the seawater Ge/Si ratio.

Potencial de cambio en las capacidades humanas de los docentes de educación básica en la región socioeducactiva de Tuxtla Gutiérrez, Chiapas, México

La investigación que se presenta fue desarrollada dentro del campo de los estudios regionales y con visión transdisciplinar. Tuvo como objetivo deconstruir conjuntamente con los participantes, las capacidades humanas regionales de nosotros los docentes de educación básica, en nuestros procesos de reflexión entre teoría y práctica, en los que se consideraron las condicionantes estructurales, en niveles macro y micro regionales, con el alcance de haber identificado el potencial de cambio en nuestra praxis de docente como acción ante nuestros alumnos, quienes configuran el tejido social de Tuxtla Gutiérrez. Desde una perspectiva sociocrítica, se tomó como punto de fuga o núcleo la teoría crítica con fundamento filosófico en la escuela de Fráncfort y con una postura epistemológica basada en el construccionismo por la estrecha relación sujeto-objeto en el estudio; por ende se empleó la metodología investigaciónacción a través de diversas técnicas e instrumentos. Los resultados fueron concentrados en categorías que facilitaron su discusión: primeramente con el potencial de cambio, que adquirió significado mediante el desarrollo de las capacidades de reflexión y conciencia del docente; luego se presentaron las capacidades humanas, de nosotros los docentes, en las que destacaron como base de otras, las capacidades de amor, autoestima y compromiso. Posteriormente, se describió la reflexión docente sobre la concepción del beneficio personal hacia el beneficio colectivo. Finalmente, se discutió sobre la proyección de la acción docente dentro de la relación alumno y región. Se concluyó que las capacidades humanas y el potencial de cambio, deconstruidos conjuntamente con los docentes participantes, fueron la respuesta del proceso investigativo en un determinado tiempo y espacio, como posibilidades de acción docente hacia la tan deseada transformación socioeducativa regional.

The microphysics of collisionless shock waves

Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments. A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics.

Réception de l’Histoire des colonies grecques dans la littérature coloniale des XVIIe-XVIIIe siècles

L’objectif de ce travail était d’apporter une réflexion sur les influences du colonialisme européen aux XVII-XVIIIe siècles. Ayant déjà rédigé mon mémoire de fin de maîtrise sur la Corinthe archaïque et ses colonies, j’ai souhaité approfondir la question, en choisissant de situer la problématique dans un contexte historiographique plus large, dans le temps comme dans l’espace. Plusieurs auteurs se sont intéressés aux réceptions de l’Antiquité à des périodes spécifiques (Grell et Alexandre le Grand en France, Richard et les influences antiques de la Révolution américaine,…). Cependant, aucune analyse sur le long terme n’avait encore été fournie, pas davantage qu’une réflexion de fonds sur la place de l’Antiquité dans la manière de penser les colonies en Europe moderne. Cet état de fait, de même que la relative rareté des sources modernes traitant des colonies grecques, m’ont obligé à élargir au maximum le champ de recherche, en y incluant des auteurs qui, s’ils ne se préoccupèrent pas de colonisation, recoururent néanmoins au précédent grec pour illustrer des problématiques de leur temps. Toutefois, il est possible de constater à quel point les répertoires historiographiques concernant la Grèce antique et ses colonisations se sont développés dans le courant de ces deux siècles qui virent l’apogée et la chute des premiers empires coloniaux européens en Amérique du nord. Si la comparaison à l’Histoire grecque ne relevait souvent que du Topos et de la propagande (comme dans le cas de la comparaison du Grand Condé ou de Louis XIV à Alexandre le Grand), son utilisation dans le cadre de controverses à plus large échelle outrepassait aussi le seul lieu commun pour s’inscrire dans un discours rhétorique plus approfondi. Le choix de la colonisation grecque comme modèle de comparaison s’imposait d’autant plus logiquement que les divers auteurs, depuis les premiers colons jusqu’aux pères fondateurs américains, insistaient sur les mérites économiques des colonies européennes. D’autres régimes, comme l’empire espagnol au XVIe siècle ou l’empire britannique au XIXe siècle, ont davantage recouru à une terminologie d’inspiration romaine. En effet, leur politique se fondait plus sur l’idée d’une extension impérialiste de l’État que sur une vision commerciale du colonialisme. L’article de Krishan Kumar demeure l’un des plus importants sur la question. La réception de l’Histoire des colonies grecques aux Temps modernes fut avant tout le fruit d’une tentative de définition du colonialisme comme phénomène global, et d’une volonté de situer les nations européennes dans un contexte remontant aux origines de l’Occident. À l’heure où l’Europe amorçait sa domination sur la totalité de la planète, et où la course à la colonisation s’accélérait, la majorité des auteurs s’abritaient derrière l’image de thalassocraties antiques qui, si elles ne dénotaient pas un pouvoir politique centralisé, n’en contribuèrent pas moins à imposer la culture fondatrice de la pensée occidentale à tout le bassin méditerranéen. Quant aux guerres qui poussèrent les puissances antiques les unes contre les autres, elles ne faisaient qu’augurer des conflits à large échelle que furent les guerres franco-britanniques du XVIIIe siècle.

Application of WRF-Chem to Forecasting PM10 Concentration Over Poland

The meteorological and chemical transport model WRF-Chem was implemented to forecast PM10 concentrations over Poland. WRF-Chem version 3.5 was configured with three one-way nested domains using the GFS meteorological data and the TNO MACC II emissions. The 48 hour forecasts were run for each day of the winter and summer period of 2014 and there is only a small decrease in model performance for winter with respect to forecast lead time. The model in general captures the variability in observed PM10 concentrations for most of the stations. However, for some locations and specific episodes, the model performance is poor and the results cannot yet be used by official authorities. We argue that a higher resolution sector-based emission data will be helpful for this analysis in connection with a focus on planetary boundary layer processes in WRF-Chem and their impact on the initial distribution of emissions on both time and space.

Exploring the World's Visual History

Thesis (Ph.D.)--University of Washington, 2016-08

Moments of Rupture: Narratological Readings of Contemporary German Literature

Thesis (Ph.D.)--University of Washington, 2016-08

Redes de conversação como possibilidade de formação do professor tutor virtual na mediação pedagógica da educação profissional a distância

A educação a distância apoiada pelos meios de comunicação digital ampliou as possibilidades de interação, flexibilizando o processo de mediação pedagógica no tempo e no espaço. Nessa perspectiva, a educação profissional democratizou seu acesso, na qual os conhecimentos de nível técnico são customizados em um Ambiente Virtual de Aprendizagem (AVA) para serem mediados a distância. Esta tese, apresentada na forma de artigos, problematiza o processo de mediação pedagógica realizado pelo professor tutor virtual na Rede e-Tec Brasil do Instituto Federal de Educação, Ciência e Tecnologia Sul-rio-grandense (IFSul) Campus Visconde da Graça (CAVG). Nesse modelo de ensino, o professor tutor virtual é contratado para atuar, pelo período de dois anos, em todas as disciplinas curriculares de um curso técnico. Se, por um lado, isso permite-lhe conhecer a realidade de seus alunos; por outro, exige-lhe um esforço pedagógico de apropriação e mediação dos conteúdos específicos nas diversas disciplinas que integram os currículos de cada curso. A pesquisa buscou conhecer como o professor tutor virtual apropria-se dos conhecimentos específicos nos cursos técnicos para mediá-los pedagogicamente com os alunos. Apresentamos, como hipótese explicativa neste estudo, que é na convivência com o professor pesquisador que o professor tutor virtual encontra a possibilidade de se apropriar dos conhecimentos curriculares para poder mediá-los pedagogicamente com os alunos. Para sustentar teoricamente nossas proposições na experiência vivida, estabelecemos uma rede de conversação com os autores Humberto Maturana, Pierre Lévy, Lee Shulman e Maurice Tardif, por meio dos conceitos: cultura em redes de conversação; inteligência coletiva; conhecimento pedagógico do conteúdo; e formação profissional docente. Como procedimento metodológico, encontramos na técnica do Discurso do Sujeito Coletivo (DSC), de Lefèvre e Lefèvre, uma estratégia de abordagem qualitativa para analisar as recorrências encontradas nos discursos dos professores tutores virtuais. O estudo aponta que uma rede de conversação recursiva entre o professor pesquisador e o professor tutor virtual possibilita a apropriação de conhecimentos técnicos e específicos necessários ao processo de mediação pedagógica com os estudantes. Essa convivência, no caminho da constituição de um coletivo inteligente, favorece o trabalho colaborativo no ambiente da tutoria, contribuindo para profissionalizar o processo de mediação pedagógica na educação profissional a distância do IFSul CAVG. Supported by digital media, distance learning has increased the possibilities of interaction, easing the process of pedagogical mediation in time and space. From this perspective, the access to professional education has been democratized: technical knowledge is customized in a Learning Managing System and later delivered by means of mediated distance education courses. Structured in a sequence of articles, this dissertation addresses the problem of the pedagogical mediation process performed by on-line tutor teachers at Rede e-Tec Brasil of the Instituto Federal Sul- rio-grandense (IF-Sul), Campus Visconde da Graça (CAVG). This model of education establishes that on-line tutor teachers are hired to work with all the curriculum courses of a technical program for two years. If, on the hand, it allows these teachers to know the reality of their students well, on the other hand it demands them a pedagogical effort of appropriation and mediation of the specific contents guiding the various courses that comprise the curriculum of each program. This research aimed to find out how on-line tutor teachers appropriate expertise from technical programs to mediate it with their students in a pedagogical way. The explanatory hypothesis given is that by working together and sharing experience with the teacher/researcher, on-line tutor teachers will be able to appropriate of curricular knowledge and pedagogically mediate it with their students afterwards. To support our theoretical propositions, a network of conversation was established with authors like Humberto Maturana, Pierre Lévy, Lee Shulman, and Maurice Tardif through the concepts of culture in networks of conversation, collective intelligence, pedagogical content knowledge, and teacher training. As a methodological procedure, the technique of the Collective Subject Discourse (CSD), by Lefèvre and Lefèvre, was found to offer a strategy of qualitative approach to analyze the recurrences seen in the speech of on-line tutor teachers. The study shows that a recursive network of conversation between the teacher/researcher and the on-line tutor teacher enables the appropriation of specific and technical knowledge required for the process of pedagogical mediation with students. The experience of sharing a consensual professional relationship, in which one respects and accepts the other as a way of establishing a collective intelligence, encourages collaborative work in the tutoring environment, helping professionalize the process of pedagogical mediation in distance professional education at IFSul CAVG.

Dynamic Resource Allocation in Wireless Heterogeneous Networks

Deployment of low power basestations within cellular networks can potentially increase both capacity and coverage. However, such deployments require efficient resource allocation schemes for managing interference from the low power and macro basestations that are located within each other’s transmission range. In this dissertation, we propose novel and efficient dynamic resource allocation algorithms in the frequency, time and space domains. We show that the proposed algorithms perform better than the current state-of-art resource management algorithms. In the first part of the dissertation, we propose an interference management solution in the frequency domain. We introduce a distributed frequency allocation scheme that shares frequencies between macro and low power pico basestations, and guarantees a minimum average throughput to users. The scheme seeks to minimize the total number of frequencies needed to honor the minimum throughput requirements. We evaluate our scheme using detailed simulations and show that it performs on par with the centralized optimum allocation. Moreover, our proposed scheme outperforms a static frequency reuse scheme and the centralized optimal partitioning between the macro and picos. In the second part of the dissertation, we propose a time domain solution to the interference problem. We consider the problem of maximizing the alpha-fairness utility over heterogeneous wireless networks (HetNets) by jointly optimizing user association, wherein each user is associated to any one transmission point (TP) in the network, and activation fractions of all TPs. Activation fraction of a TP is the fraction of the frame duration for which it is active, and together these fractions influence the interference seen in the network. To address this joint optimization problem which we show is NP-hard, we propose an alternating optimization based approach wherein the activation fractions and the user association are optimized in an alternating manner. The subproblem of determining the optimal activation fractions is solved using a provably convergent auxiliary function method. On the other hand, the subproblem of determining the user association is solved via a simple combinatorial algorithm. Meaningful performance guarantees are derived in either case. Simulation results over a practical HetNet topology reveal the superior performance of the proposed algorithms and underscore the significant benefits of the joint optimization. In the final part of the dissertation, we propose a space domain solution to the interference problem. We consider the problem of maximizing system utility by optimizing over the set of user and TP pairs in each subframe, where each user can be served by multiple TPs. To address this optimization problem which is NP-hard, we propose a solution scheme based on difference of submodular function optimization approach. We evaluate our scheme using detailed simulations and show that it performs on par with a much more computationally demanding difference of convex function optimization scheme. Moreover, the proposed scheme performs within a reasonable percentage of the optimal solution. We further demonstrate the advantage of the proposed scheme by studying its performance with variation in different network topology parameters.

Estéticas de la hibridación, del cuerpo transhumano al cuerpo posthumano

Estéticas de la hibridación. Del cuerpo transhumano al cuerpo posthumano, es una investigación que evidencia la crisis de la razón desencadenada por la posmodernidad. Inmersas las nuevas narrativas utópicas y distópicas del cuerpo humano, su complejidad, sus coordenadas en tiempo y espacio y su despliegue multidimensional como soporte artístico. Aporta en la discusión académica sobre el transhumanismo y posthumanismo como procesos de hibridación corporal a través de la intervención de las nuevas tecnologías y el despliegue de otras realidades replicadas en el ciberespacio. Vincula estas teorías trans-/posthumanistas establecidas recientemente con discursos y gestos artísticos generados en la globalidad y el entorno a través de la propuesta de un canon emergente.

Performance analysis in soccer: applications of player tracking technology

The aim of this thesis was threefold, firstly, to compare current player tracking technology in a single game of soccer. Secondly, to investigate the running requirements of elite women’s soccer, in particular the use and application of athlete tracking devices. Finally, how can game style be quantified and defined. Study One compared four different match analysis systems commonly used in both research and applied settings: video-based time-motion analysis, a semi-automated multiple camera based system, and two commercially available Global Positioning System (GPS) based player tracking systems at 1 Hertz (Hz) and 5 Hz respectively. A comparison was made between each of the systems when recording the same game. Total distance covered during the match for the four systems ranged from 10 830 ± 770 m (semi-automated multiple camera based system) to 9 510 ± 740m (video-based time-motion analysis). At running speeds categorised as high-intensity running (>15 km⋅h-1), the semi-automated multiple camera based system reported the highest distance of 2 650 ± 530 m with video-based time-motion analysis reporting the least amount of distance covered with 1 610 ± 370 m. At speeds considered to be sprinting (>20 km⋅h-1), the video-based time-motion analysis reported the highest value (420 ± 170 m) and 1 Hz GPS units the lowest value (230 ± 160 m). These results demonstrate there are differences in the determination of the absolute distances, and that comparison of results between match analysis systems should be made with caution. Currently, there is no criterion measure for these match analysis methods and as such it was not possible to determine if one system was more accurate than another. Study Two provided an opportunity to apply player-tracking technology (GPS) to measure activity profiles and determine the physical demands of Australian international level women soccer players. In four international women’s soccer games, data was collected on a total of 15 Australian women soccer players using a 5 Hz GPS based athlete tracking device. Results indicated that Australian women soccer players covered 9 140 ± 1 030 m during 90 min of play. The total distance covered by Australian women was less than the 10 300 m reportedly covered by female soccer players in the Danish First Division. However, there was no apparent difference in the estimated "#$%&', as measured by multi-stage shuttle tests, between these studies. This study suggests that contextual information, including the “game style” of both the team and opposition may influence physical performance in games. Study Three examined the effect the level of the opposition had on the physical output of Australian women soccer players. In total, 58 game files from 5 Hz athlete-tracking devices from 13 international matches were collected. These files were analysed to examine relationships between physical demands, represented by total distance covered, high intensity running (HIR) and distances covered sprinting, and the level of the opposition, as represented by the Fédération Internationale de Football Association (FIFA) ranking at the time of the match. Higher-ranking opponents elicited less high-speed running and greater low-speed activity compared to playing teams of similar or lower ranking. The results are important to coaches and practitioners in the preparation of players for international competition, and showed that the differing physical demands required were dependent on the level of the opponents. The results also highlighted the need for continued research in the area of integrating contextual information in team sports and demonstrated that soccer can be described as having dynamic and interactive systems. The influence of playing strategy, tactics and subsequently the overall game style was highlighted as playing a significant part in the physical demands of the players. Study Four explored the concept of game style in field sports such as soccer. The aim of this study was to provide an applied framework with suggested metrics for use by coaches, media, practitioners and sports scientists. Based on the findings of Studies 1- 3 and a systematic review of the relevant literature, a theoretical framework was developed to better understand how a team’s game style could be quantified. Soccer games can be broken into key moments of play, and for each of these moments we categorised metrics that provide insight to success or otherwise, to help quantify and measure different methods of playing styles. This study highlights that to date, there had been no clear definition of game style in team sports and as such a novel definition of game style is proposed that can be used by coaches, sport scientists, performance analysts, media and general public. Studies 1-3 outline four common methods of measuring the physical demands in soccer: video based time motion analysis, GPS at 1 Hz and at 5 Hz and semiautomated multiple camera based systems. As there are no semi-automated multiple camera based systems available in Australia, primarily due to cost and logistical reasons, GPS is widely accepted for use in team sports in tracking player movements in training and competition environments. This research identified that, although there are some limitations, GPS player-tracking technology may be a valuable tool in assessing running demands in soccer players and subsequently contribute to our understanding of game style. The results of the research undertaken also reinforce the differences between methods used to analyse player movement patterns in field sports such as soccer and demonstrate that the results from different systems such as GPS based athlete tracking devices and semi-automated multiple camera based systems cannot be used interchangeably. Indeed, the magnitude of measurement differences between methods suggests that significant measurement error is evident. This was apparent even when the same technologies are used which measure at different sampling rates, such as GPS systems using either 1 Hz or 5 Hz frequencies of measurement. It was also recognised that other factors influence how team sport athletes behave within an interactive system. These factors included the strength of the opposition and their style of play. In turn, these can impact the physical demands of players that change from game to game, and even within games depending on these contextual features. Finally, the concept of what is game style and how it might be measured was examined. Game style was defined as "the characteristic playing pattern demonstrated by a team during games. It will be regularly repeated in specific situational contexts such that measurement of variables reflecting game style will be relatively stable. Variables of importance are player and ball movements, interaction of players, and will generally involve elements of speed, time and space (location)".

Papel do PCT na diferenciação pedagógica e curricular de alunos com DEA/Dislexia

O presente estudo partiu de preocupações da prática relacionadas com o papel do PCT no desenvolvimento pedagógico e curricular sobretudo de alunos com dislexia. No sentido de se responder à pergunta de partida: “de que forma a diferenciação pedagógica e curricular dos alunos com DEA/Dislexia, é contemplada no PCT?” elaborou-se um quadro teórico onde se começou por discutir o papel da escola recorrendo inclusivamente à sua perspectivação histórica. Esta permitiu perceber a escola actual nomeadamente nas tensões entre os processos de massificação escolar conducentes a uma hegemonia do currículo e os processos de flexibilização curricular. O nosso interesse principal situou-se nestes últimos pela sua importância para a diferenciação curricular e pedagógica na sala de aula necessária para os alunos com dislexia. A formação dos professores desempenha neste contexto uma grande relevância, pelo que lhe atribuímos elevada importância. Utilizando como instrumentos de recolha inquéritos por questionário articulados com a análise dos PCTs inquirimos uma amostra de vinte e oito professores de um agrupamento de escolas do distrito de Santarém sobre a sua percepção face à dislexia e à importância dada à utilização do PCT. Os dados recolhidos e tratados permitiram verificar que nem os PCT são encarados como um instrumento de diferenciação curricular e pedagógica, resultando em algumas contradições entre o que se diz fazer e o que se faz efectivamente, nem a DEA/Dislexia é encarada como um problema, que apesar de real não se vê contemplada, de forma explícita nos PCT. Desta forma, consideramos que o estudo realizado (embora limitado no tempo e espaço) permite desvendar algumas das suas representações mostrando uma forte relação entre a ausência de formação e o impacto que esta lacuna tem nas práticas docentes.

Princípios e fundamentos da pedagogia da alternância: alguns desdobramentos atuais

The Pedagogy of Alternation (PA) is a differentiated teaching methodology, originally created to meet the needs that involve the population of the field. Through its educational procedures, distinct from the traditional education, demand, with autonomy, to form children and young people through the articulation of time and space, and involve the family and community in the educational process and in local development. Having been established as an alternative that generated positive results, the PA has expanded the world and today, with the formation of various movements, is present on five continents. In Brazil, there are two active movements using the PA, the Italian, which afforded the EFAs and the French, responsible for implantation the CFRs. Is in this context, the present research is inserted, which the following objective: to analyse the origins, principles and theoretical-methodological foundations of Pedagogy of Alternation and its implantation in Brazil, as well as some of its current unfolding. With this, it takes into consideration, besides the Brazilian movements, those who influenced its origin, the raised in France and the raised in Italy. The study is characterized as a theoretical, qualitative, bibliographic and documental. The data collection was carried out by searching in the CEPAD/UTFPR database and in the web pages of the institutions involved. After the identification and selection of documents and bibliographies, was realized the qualitative analysis of the data. The results indicate that the Pedagogy of Alternation practiced by the Italian EFAs and the Brazilian CFRs has undergone significant changes over time, keeping only firm the principle alternation of time and space, while the French MFRs and Brazilian EFAs, passed by adaptations, but still solid to principles of PA. The survey also showed that the CFRs in Parana are in a situation of instability about their future, since the links with the government are weakened. Thus, the present study sought to reflect on the meaning and the scope of the PA and its foundations that guarantee the autonomy and strength of this methodology in their places of origin. Therefore, the research presents contributions regarding the elucidation about expansion process of the movements in the three covered countries as well as those faced tensions by each and their transformations in order to highlight the importance of PA for education, comprehensive training of young and to development of the middle.

Variational ensemble Kalman filtering applied to data assimilation problems in computational fluid dynamics

One challenge on data assimilation (DA) methods is how the error covariance for the model state is computed. Ensemble methods have been proposed for producing error covariance estimates, as error is propagated in time using the non-linear model. Variational methods, on the other hand, use the concepts of control theory, whereby the state estimate is optimized from both the background and the measurements. Numerical optimization schemes are applied which solve the problem of memory storage and huge matrix inversion needed by classical Kalman filter methods. Variational Ensemble Kalman filter (VEnKF), as a method inspired the Variational Kalman Filter (VKF), enjoys the benefits from both ensemble methods and variational methods. It avoids filter inbreeding problems which emerge when the ensemble spread underestimates the true error covariance. In VEnKF this is tackled by resampling the ensemble every time measurements are available. One advantage of VEnKF over VKF is that it needs neither tangent linear code nor adjoint code. In this thesis, VEnKF has been applied to a two-dimensional shallow water model simulating a dam-break experiment. The model is a public code with water height measurements recorded in seven stations along the 21:2 m long 1:4 m wide flume’s mid-line. Because the data were too sparse to assimilate the 30 171 model state vector, we chose to interpolate the data both in time and in space. The results of the assimilation were compared with that of a pure simulation. We have found that the results revealed by the VEnKF were more realistic, without numerical artifacts present in the pure simulation. Creating a wrapper code for a model and DA scheme might be challenging, especially when the two were designed independently or are poorly documented. In this thesis we have presented a non-intrusive approach of coupling the model and a DA scheme. An external program is used to send and receive information between the model and DA procedure using files. The advantage of this method is that the model code changes needed are minimal, only a few lines which facilitate input and output. Apart from being simple to coupling, the approach can be employed even if the two were written in different programming languages, because the communication is not through code. The non-intrusive approach is made to accommodate parallel computing by just telling the control program to wait until all the processes have ended before the DA procedure is invoked. It is worth mentioning the overhead increase caused by the approach, as at every assimilation cycle both the model and the DA procedure have to be initialized. Nonetheless, the method can be an ideal approach for a benchmark platform in testing DA methods. The non-intrusive VEnKF has been applied to a multi-purpose hydrodynamic model COHERENS to assimilate Total Suspended Matter (TSM) in lake Säkylän Pyhäjärvi. The lake has an area of 154 km2 with an average depth of 5:4 m. Turbidity and chlorophyll-a concentrations from MERIS satellite images for 7 days between May 16 and July 6 2009 were available. The effect of the organic matter has been computationally eliminated to obtain TSM data. Because of computational demands from both COHERENS and VEnKF, we have chosen to use 1 km grid resolution. The results of the VEnKF have been compared with the measurements recorded at an automatic station located at the North-Western part of the lake. However, due to TSM data sparsity in both time and space, it could not be well matched. The use of multiple automatic stations with real time data is important to elude the time sparsity problem. With DA, this will help in better understanding the environmental hazard variables for instance. We have found that using a very high ensemble size does not necessarily improve the results, because there is a limit whereby additional ensemble members add very little to the performance. Successful implementation of the non-intrusive VEnKF and the ensemble size limit for performance leads to an emerging area of Reduced Order Modeling (ROM). To save computational resources, running full-blown model in ROM is avoided. When the ROM is applied with the non-intrusive DA approach, it might result in a cheaper algorithm that will relax computation challenges existing in the field of modelling and DA.

Dinâmicas sócioeconômicas na prática dos feirantes agricultores familiares de Chapecó-SC

This thesis deals with the insertion of family farmers market that act as market traders in the city of Chapecó, state of Santa Catarina. In order to trust, reciprocity and relations of time and space dynamics present in the practice of open-air market is analyzed. From understanding the outdoor market as an extension of the activities of farms, a form of local construction market, we need new ways to evaluate the inclusion of family farming in trade. In this regard, the importance of local markets characterized by autonomy in the food hegemonic system. To this end, it uses what the peculiarities present in the practice of street fairs, its historical development, the number of farmers who act as market participants, the number of traders in the city and its surroundings, the diversity of products offered, the marketing channel access by traders and market relations farmers who act as market participants. Finally, based on the responses of suppliers and content analysis, it was possible to show how present in the social dynamics of free trade: the trusted face to face representations, reciprocity and relations of time and space between the co-present agents in the market dynamics of family farmers fair. For the study context, these representations show how important non-economic values that help build identities that relate to the strategies of social reproduction and overcoming dominant market model.