Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-02-29T13:41:39Z No. of bitstreams: 1 Lanaira da Silva_.pdf: 1030082 bytes, checksum: 7ad012030e40ab9677f8e998dd87e93a (MD5) / Made available in DSpace on 2016-02-29T13:41:39Z (GMT). No. of bitstreams: 1 Lanaira da Silva_.pdf: 1030082 bytes, checksum: 7ad012030e40ab9677f8e998dd87e93a (MD5) Previous issue date: 2015-12-14 / Nenhuma / A partir da Crítica Hermenêutica do Direito (Lenio Streck), o presente estudo buscou abordar, em uma perspectiva comparativa, aspectos elementares da estruturação normativa na Teoria e Metódica Estruturante do Direito (Friedrich Müller). Nesse sentido, o ponto fundamental na discussão proposta é o modo como se dão as concepções normativas de cada teoria. Tanto a Crítica Hermenêutica do Direito quanto a Teoria Estruturante do Direito distinguem-se de tantas outras teorias (de acepções positivistas) por apresentarem originalmente um tratamento diferenciado a essa questão que se revela como um ponto de partida essencial: a norma. A partir dessa constatação, ao trazer o debate para o interior dos paradigmas filosóficos (com inserção de um teorema fundamental da Filosofia Hermenêutica: a diferença ontológica), foi possível problematizar a amplitude de como esta distinção fundamental é capaz de desvelar, sob um outro viés, a diferença existente entre texto e norma. Dentro de um “chão” comum entre Crítica Hermenêutica, e Teoria Estruturante, em virtude da influente presença da “Hermenêutica Filosófica”, foram levantados alguns pontos de (des)encontros entre os autores, observando um critério fundamental para que uma teoria se designe “Pós-positivista”: o enfrentamento da discricionariedade. / From the “Hermeneutical Critique of law” (Lenio Streck), this study sought to address in a comparative perspective, elementary aspects of the regulatory structure in Theory and Methodical Structuring Law (Friedrich Müller). In this sense, the fundamental point in the proposed discussion is how to give the normative conceptions of each theory. Both Hermeneutical Critique of Law as the Structuring Theory of Law distinguished from many other theories (of positivists meanings) originally presented by different treatment to that question turns out to be an essential starting point: the norm. From this evidence, to bring the debate to the interior of the philosophical paradigms (with insertion of a fundamental theorem of Hermeneutics Philosophy: the ontological difference) it was possible to discuss the scope of how this fundamental distinction is able to reveal, under another, the distinction between text and standard. Within a "commonground" among “Hermeneutical Critique” and “Structuring Theory”, due to the influential presence of the "Philosophical Hermeneutics", some points were raised (un) meetings between authors observing a fundamental criterion for a theory designating of "Post -positivism ": the confrontation of discretion.

Made available in DSpace on 2016-04-26T20:23:32Z (GMT). No. of bitstreams: 1 Lucas de Faria Rodrigues.pdf: 979982 bytes, checksum: 84c6dded95dff730cb73c29995efa731 (MD5) Previous issue date: 2015-03-03 / This work aims to seek the meaning of Ecological Constitution, defined as the set of constitutional rules directed to protection of the environment, from an effective dialogue with the natural sciences. The fundamental premise, from which developed the thesis, is that understanding the characteristics of the good tutored is essential to the full exercise of guardianship. From there we sought to dogmatic bases in Law to allow an effective interdisciplinary dialogue. In Law, the foundation was the Structuring Theory of Friedrich Müller and his idea of the rules concretization. From this theory was possible to extract the structure of the legal norm, which is not given prior to the interpreter, is built in the case, from its normative program and its normative ambit. The text is only part of the process, does not contain in itself the normativity. There is no legal norm (and also environmental norm) previously defined. The choice of Ecology was not arbitrary in this context of dialogue, but enforcement of the normative ambit of environmental norm. From this discipline was possible to extract elements as the network pattern (or the interconnection) and cooperation. Only from the instant you properly understand the nature relationships, will be possible to realize the expected protection. These findings lead to the orderly operation of government, focused on joint efforts to safeguard the common good. These characteristics should reflect the pattern of action of the constituted authorities, in the moment of the environmental norm concretization, from maxims as coordination, cohesion and cooperation. It has been shown that the intensity and mode of influence of these elements will vary as the normative program requires the search for extra-legal elements to delimit the respective normative ambit. Escape of these elements leads to a risk of Constitutional symbolization. There is a practical reflection in the process of concretization, with impacts on the activity of all state powers involved (Legislative, Executive and Judiciary). Thus, there are impacts on the solution of concrete cases placed to the examination of the judiciary, but also in shaping and implementing public policies. It´s necessary to speak in a guideline for dealing with the environmental issues / O presente trabalho tem como objetivo buscar o sentido da Constituição Ecológica, definida como o conjunto de normas constitucionais voltadas à tutela do meio ambiente, a partir de um diálogo efetivo com as ciências naturais. A premissa fundamental, a partir da qual desenvolveuse a dissertação, é de que compreender as características do bem tutelado é essencial para o pleno exercício desta tutela. A partir daí buscou-se as bases dogmáticas no Direito a permitir um diálogo interdisciplinar efetivo. No Direito, o fundamento foi a Teoria Estruturante de Friedrich Müller e sua ideia de concretização das normas. A partir desta teoria foi possível extrair a estrutura da norma jurídica, que não é um dado prévio ao intérprete, constrói-se no caso concreto, a partir do seu programa normativo e seu âmbito normativo. O texto é apenas parte do processo, não contém em si a normatividade. Não existe norma jurídica (e também norma ambiental) definida previamente. A escolha da Ecologia não foi arbitrária neste contexto de diálogo, mas imposição do próprio âmbito normativo da norma ambiental. Desta disciplina foi possível extrair elementos como o padrão de redes (ou a interconexão) e a cooperação. Só a partir do instante em que se compreender adequadamente as relações da natureza, poder-se-á ter consciência da tutela esperada. Estas constatações levam a uma atuação ordenada dos poderes públicos, voltada à conjugação de esforços para salvaguardar um bem comum. Estas características devem refletir no padrão de ação dos poderes constituídos, no momento da concretização da norma ambiental, a partir de máximas como coordenação, coesão e cooperação. Mostrou-se que a intensidade e o modo de influência destes elementos variarão conforme o programa normativo requeira a busca de elementos extrajurídicos para delimitar o respectivo âmbito normativo. Fugir destes elementos leva a um risco de simbolização da Constituição. Há um reflexo prático no processo de concretização, com impactos na atividade de todos os Poderes estatais envolvidos (Legislativo, Executivo e Judiciário). Assim, há impactos na solução de casos concretos postos a exame do Judiciário, mas também na formatação e execução de políticas públicas. É necessário se falar em uma verdadeira diretriz de enfrentamento das questões ambientais

In the present diploma thesis named "Acquisition of Shares and Subsequent Merger in Logistics Company" is given a broad overview of difficult processes of mergers and acquisitions as a useful tool for establishing a leveraged buyout (LBO) in terms of Czech business practice. The goal of the thesis is to analyze the specific acquisition process of obtaining a 100% stake in the company and subsequent merger. The thesis also aims to give readers a comprehensive guide of each step of a complex business transformation process through merger and simultaneously propose the optimal structuring of an acquisition of shares from other shareholders, resulting in a 100% stake in the company. In the form of present thesis readers get a manual with specific instructions how to proceed in the case of strategic decisions about leveraged buyouts (LBO) and subsequent merger.

Conceitos e técnicas são ensinados em ambientes educacionais e deveriam ser aprendidos; porém, os exames nacionais de larga escala têm mostrado resultados indesejados, evidenciando uma lacuna na aprendizagem dos nossos alunos. Segundo Sanchez (2013), nos cursos de graduação em Ciências Contábeis, os principais erros conceituais cometidos pelos estudantes são: uso equivocado dos conceitos de caixa e competência e erros matemáticos. A definição de erro conceitual é referida na literatura sobre misconceptions (Chi, 1992) em que existe uma apresentação padrão na forma em que o erro desponta e um relacionamento incompatível entre os conceitos novos, a serem aprendidos pelos alunos, e os conceitos prévios, já existentes. Os erros conceituais têm seis características: são robustos, consistentes, persistentes, homogêneos, recapitulados e sistemáticos. Por isso, são difíceis de serem corrigidos. Chi et al (1994) utilizam da teoria da estruturação do conhecimento, em que definem que os conceitos são classificados em categorias ao serem aprendidos. Porém, conceitos que são classificados erroneamente transformam-se em erros conceituais robustos: são difíceis de serem aprendidos, pela dificuldade em transpor o conceito para a categoria adequada. Com base na definição de misconception e da estruturação dos conceitos em categorias, buscou-se entender como os estudantes formam os erros conceituais e, com base nestes tipos de erro encontrados e nas seis características dos padrões de erros, coletamos evidências da formação e superação dos erros por parte dos alunos. Estas evidências nos auxiliaram na criação de uma estratégia de ensino, construída com base na estruturação do conhecimento e, que seja diferente da estratégia \"comum\" de aula de Contabilidade Introdutória, que é o primeiro contato dos estudantes da área de negócios com contabilidade, com intuito de responder a nossa questão de pesquisa: \"Qual o impacto (proporção e sentido) da adoção desta estratégia de ensino baseada em erros conceituais no aprendizado dos estudantes?\" O impacto da estratégia foi motivacional, pois fez os alunos refletirem sobre os erros conceituais, mas insuficiente para aumentar a proporção de acertos nas avaliações realizadas. / Concepts and techniques are taught in educational settings and should be learned; however, large-scale national exams have shown undesirable results, evidencing a learning gap in our students. According to Sanchez (2013), in the undergraduate courses in Accounting, the main misconception made by students are: misuse of concepts of cash and accrual and mathematical errors. The definition of misconception is referred to in the literature (Chi, 1992) in which there is a standard presentation in the form in which the error emerges and an incompatible relationship between the new concepts to be learned by the students and the prior knowledge already existing. Misconception have six characteristics: they are robust, consistent, persistent, homogeneous, recapitulated and systematic. Therefore, they are difficult to correct. Chi et al. (1994) use the theory of knowledge structuring, where they define that concepts are classified into categories when they are learned. However, concepts that are misclassified become robust conceptual errors: they are difficult to learn because of the difficulty in transposing the concept into the appropriate category. Based on the definition of misconception and the structuring of concepts into categories, we sought to understand how students form misconception and, based on these types of errors found and on the six characteristics, we collect evidence of the formation and overcoming of errors on the part of the students. These evidences helped us in creating a teaching strategy, based on the structuring of knowledge and that is different from the \"common\" strategy of First Accounting Class, which is the first contact of the students of the business area with accounting, with In order to answer our research question: \"What is the impact (proportion and signal) of adopting this teaching strategy based on conceptual errors in learning?\" The impact of the strategy was motivational, as it made the students reflect on the conceptual errors, but insufficient to increase the proportion of correctness in the realized evaluations.

Esta pesquisa investigou na produção acadêmica sobre EaD as questões emergentes do seu paradigma educacional em função da inserção das TDIC (Tecnologias Digitais de Informação e de Comunicação) por meio de plataformas virtuais com o objetivo de compreender principais tendências, contribuições e desafios identificados. Descreve os principais conceitos ligados à EaD e às plataformas virtuais de aprendizagem, destacando-se as características do Moodle. Apresenta as gerações da modalidade EaD, a legislação vigente, amplo número de produções científicas nacionais, predominante em cursos da rede privada da Educação Superior. Questiona seu paradigma como diferenciado do modelo tradicional de ensino e como são tratados os estruturantes didáticos em suas propostas de cursos bem como questões referentes à formação docente e à inserção das TDIC em diferentes modalidades de EaD. Focaliza a opção metodológica por uma pesquisa de natureza exploratória e descritiva de referências e a criação de categorias de análise ligadas aos estruturantes didáticos. Identifica as tendências, contribuições e desafios da EaD articulada à presença ou não dos estruturantes didáticos (contexto institucional, modalidades, fundamentação da visão de ensino e de aprendizagem, inserção dos recursos tecnológicos e suas contribuições aos processos de ensino e de aprendizagem e processo de avaliação). Conclui pela necessidade de uma ressignificação educacional da inserção das Tecnologias Digitais de Informação e Comunicação (TDIC) que reduza a reprodução da sala de aula tradicional e que forme docentes capazes de compreender a complexidade existente na convergência de dimensões antes menos integradas ao processo de ensino e de aprendizagem como as competências cognitivas, emocionais e éticas. A inserção das TDIC implica planejamento e formação prévia e continuada dos professores para evitar o que ocorre atualmente com os modelos tutoriais de EaD com estratégias pré-planejadas, processos diretivos rígidos, com memorização de fatos e/ou informações isoladas, reforçando paradigmas educacionais tradicionais. Os estruturantes didáticos precisam ser considerados nas articulações dos diferentes saberes docentes (conhecimentos específicos, conhecimentos pedagógicos e conhecimentos tecnológicos) com foco prioritário no protagonismo discente da aprendizagem e na interação colaborativa. O maior desafio consiste em reduzir a ênfase dada a tecnologia, como se ela, por si só, pudesse ser responsável pela melhoria da democratização e qualidade da educação. / This research investigated the academic production about EaD emerging issues of their educational paradigm according to the insertion of TDIC (Digital Information and Communication Technologies) through virtual platforms with the goal of understand main tendencies identified contributions and challenges. Describes the major concepts connected to distance education and virtual learning platforms highlighting the features of Moodle. Displays the generations of distance education modality, the current legislation, large number of national, prevailing scientific production in the private courses of higher education network. Questions his paradigm as distinguished from the traditional model of teaching and learning as the structuring are treated in their proposed courses as well as issues related to teacher training and the integration of TDIC in various forms of distance education. Focuses on the methodological option for an exploratory and descriptive research references and the creation of categories related to structuring didactic. Identifies trends, contributions and challenges of distance education articulated the presence or absence of didactic structuring (institutional context, procedures, grounds of educational vision and learning, integration of technological resources and their contributions to teaching and learning processes and evaluation process ). It concludes for the need for a redefinition of educational integration of Information and Communication Digital Technologies (TDIC) that reduces the reproduction of the traditional classroom, and form teachers able to understand the complexity existing in the convergence of dimensions before less integrated into the teaching process and learning as cognitive, emotional and ethical skills. The insertion of TDIC implies planning and prior and continued training of teachers to avoid what is currently happening with the tutorials models of distance education with pre-planned strategies, hard directive processes, memorization of facts and / or isolated information, reinforcing traditional educational paradigms. The didactic structuring need to be considered in the joints of different teaching knowledge (specific knowledge, pedagogical knowledge and technological knowledge) with priority focus on the role of student learning and collaborative interaction. A major challenge is to reduce the emphasis on technology, as if she alone, could be responsible for improving the quality of education and democratization.

La structuration laser femtoseconde (fs) de verres d’oxydes est un domaine de larecherche en pleine expansion. L’interaction laser-matière est utilisée pour sa facilité de miseen oeuvre et les nombreuses applications découlant de la fabrication des composantsphotoniques. En effet, un faisceau d’impulsions ultra-courtes focalisé dans un matériautransparent atteint une intensité suffisante pour modifier en 3D la matière à des échelles microetnanométrique. Ce mémoire se compose de deux volets. Le premier volet traite del’interaction laser fs en surface de verres menant à une auto organisation périodique de lamatière. L’influence du dopage ions photosensibles et des paramètres d’irradiation laser sontétudiées afin d’appuyer le modèle d’incubation pour la formation de nanoréseaux. À travers uneapproche innovante, il a été permis le contrôle de ces structures nanométriques périodiquespour de futures applications. Le second volet traite de cristallisation localisée de volume.Plusieurs matrices vitreuses, avec différents dopages en ion argent, ont été étudiées pourcomprendre les mécanismes de précipitation de nanoparticules d’argent (Ag-NPs). Ce travaildémontre le lien entre la physicochimie des verres et le caractère hors équilibrethermodynamique de l’interaction qui influence les conditions de nucléation/croissances des Ag-NPs. Les résultats sont comparés aux modélisations de la réponse optique du plasmon desurface des Ag-NPs. Les nombreuses perspectives de ce travail ouvrent sur de nouvellesapproches quant à la caractérisation, aux applications et à la compréhension de l’interactionlaser fs pour l’inscription de briques photoniques dans des verres d’oxydes. / Femtosecond direct laser writing (fs-DLW) of oxide glasses is a growing researchand development area. It is also increasingly used in the high-tech industry thanks to its simpleimplementation and numerous possible applications emerging from the photonic componentsmanufacture. Indeed, an ultra-short focused beam in a transparent material reaches a sufficientintensity to 3D modify the material on micro- or nanometer scale. However, the fs-DLW regimesat such high intensity are not completely understood, and the materials, already used, are notperfectly adapted for new photonics applications. This research work aims to provide answersto those open questions. This thesis is based on two thrusts. The first one addresses the issueof the glass surface DLW with fs pulses which lead to self organized periodic structures. Theinfluence of photosensitive doping ions and irradiation parameters are studied to support theincubation model for nanogratings surface formation. This study allows the control of theseperiodic nanostructures for further applications. The second thrusts deals with localized volumecrystallization. Several glassy matrices with various silver oxide doping have been studied tounderstand the mechanisms of silver nanoparticles (Ag-NPs) precipitation. This workdemonstrates the link between the physical chemistry of the glass and the non-equilibriumthermodynamic state during fs-DLW to influence nucleation and growth conditions of Ag-NPs.These results are compared to models that describe the optical responses of plasmonicbehavior. This research opens on new approaches and prospects for applications andunderstandings of fs-DLW of novel photonic bricks.

Les revêtements organiques déposés en surface de tuyaux en fonte ductile ont pour vocation d’assurer une protection (notamment la résistance chimique, la tenue à la corrosion) vis-à-vis des effluents agressifs transportés. Pour assurer l’adhérence entre le revêtement (époxy) et son substrat, une préparation de surface est souvent nécessaire. Parmi les procédés conventionnels, le grenaillage est la solution la plus utilisée. Simple à mettre en œuvre et d’efficacité prouvée, il permet d’assurer le décapage de la surface tout en générant une rugosité adaptée. Si la solution est approuvée, des questions subsistent néanmoins quant à l’influence respective de la topographie et de la physico-chimie des surfaces. De plus, encouragées par les nouvelles réglementations environnementales, de nouvelles techniques de préparation de surface se développent.Le travail présenté s’est alors attaché à évaluer l’effet de nouvelles techniques de préparation comme le laser de structuration et le jet d’eau à ultra haute pression à comparer à d’autres procédés conventionnels tels que le brossage et le sablage. Ces nouvelles alternatives vont permettre alors de mieux comprendre l’influence du décapage et de la rugosité de surface avant la mise en peinture.Enfin, les différents résultats obtenus ont été alors spécifiquement analysés pour permettre la compréhension des phénomènes ou mécanismes d’adhésion se produisant à l’interface du couple époxy/substrat, d’un point de vue mécanique et physico-chimique. Divers moyens d’analyses ont alors pu être mis en œuvre pour caractériser les surfaces d’un point de vue morphologique (ratio de surface) et chimique (spectroscopies Raman et photoélectronique à rayons X (XPS)) pour évaluer la tenue interfaciale (test de traction adhérence). / Organic coatings applied on the surface of cast iron pipes ensure very good chemical and anti-corrosion protection against aggressive effluents. To improve adherence between coating (epoxy) and substrate, a surface preparation is required. Among conventional processes shot blasting has emerged as the most efficient and cheapest solution for ensuring stripping while generating adapted roughness. However, as it may enhance both mechanical anchorage and chemical bonding a better understanding of these phenomena should be developed. Besides new eco-friendly alternatives were investigated.Indeed, new techniques were evaluated, i.e. laser structuring and an ultra-high pressure water jet whose major benefits are understanding the effect of ablation and surface roughness prior to applying a coating. Moreover, two other conventional processes (sand blasting and brushing) were introduced to obtain a various roughness.Results obtained were then analyzed to further understand bonding mechanisms at the interface.Several processes were then implemented to evaluate the surface morphology as well as the surface chemistry (spectroscopy Raman and XPS) correlated to the adhesion mechanisms

Industrial companies that carry on innovation and operation must have well-organized and capable business systems and processes. Customer needs, market demands, global competition and technological changes drive the companies to be more adaptable, flexible and dynamic. By working in network structures as extended enterprises, the companies face new possibilities and new challenges. Design, manufacturing and delivery of high quality products to competitive prices to the customers are essential for industrial companies. Holistic view of the product life cycle from technology development, via product and business system development and realization, to business operation, is important for sustainable industrial companies. A company with engineering and manufacturing of products in a business context needs to have effective innovation of business system and process. Business innovation encompasses the area from business idea to business operation and includes customer demands and solutions. The main part of business innovation is development of the product platform including product and support structures. Product variants are created and realized by various configurations of products and production systems. The thesis is elucidating that business innovation can be carried out by working in a systematic and structured way and by utilizing engineering design theories and methods. The business models, based on a new theory with a new navigation tool for interactions, are describing which activities should be performed in business innovation with product platform development and product structuring. For companies in business with changes, innovations can create new markets and products. Well-managed and innovative companies have good possibilities to be competitive in a tough business environment. The creation of business innovation models has been carried out according to a hermeneutic research method. The research work followed the hermeneutic circle or spiral. The thesis introduces a new dimension to the design area, namely business innovation or engineering, corresponding to business design and development. Business innovation is also a new type of innovation, combining technological, product, process, market and organizational innovations in industrial companies. / QC 20100920

This thesis is mainly concerned with some important properties of complex fluids, and how these properties are influenced by structures in the nano/mesoscopic scale. Short-range assembly of the constituent molecules results in an amazing variety of phase behavior in these systems. Liquid-liquid phase transitions, or transitions from a homogeneous(mixed) phase to an immiscible phase (two-phase coexistence), are the outcome of a competition between entropy and short-ranged attractive forces, and form an important part of this thesis. A rich phase behavior is uncovered by a detailed study of liquid-liquid phase transitions in a mixture of ethanol(E) and water(W), induced by the addition of ammonium sulfate(AS) ions (E and W are otherwise completely soluble in each other). This is the main motivation for choosing this system. Furthermore, experimental evidence of the presence of supramolecular association in alcohol-water mixtures [J.-H. Guo et al., Phys. Rev Lett, 91, 15401(2003)] enhances our interest to study the phase behavior in more detail. The presence of a critical point, at which there is a second order phase transition, is quite common in complex fluids. An issue which has been the subject of extensive scientific research in recent years is the influence of nano/mesoscopic structure on the critical behavior of these fluids corresponds to the Ising universality class. However, the approach to the asymptotic regime is governed by a competition between the correlation length of critical concentration fluctuations and the additional length scale arising due to structuring., which results in a crossover from the universal Ising behavior to the mean-field behavior, sometimes within the critical domain. This phenomenon of crossover criticality is presently explored in the E + W + AS system. A significant portion of the thesis presents explorations on the critical behavior in the vicinity of special critical points (SCP), which are formed by the coalescence of two or more critical points. Recentrant liquid-liquid phase transitions observed in the E + W + AS system, furnishes an unique opportunity for the realization of three SCPs – the double critical point(DCP) and the critical double point(CDP) formed by the merger of two critical points , and a critical inflection point(CIP), formed by the merger of three critical points. A CIP had not been experimentally realized prior to the studies presented in this thesis. Apart from the above studies investigations are also carried out on the conformational changes of a technologically important conducting polymer, polyethylene dioxythiophene doped with polystyrene suflonate (PEDOT-PSS), in various solvents. The electrical and optical properties of the polymer films get enhanced when solution processed with specific solvents. The experiments presented in this thesis are directed at unraveling the role of conformational modifications in the electrical and optical properties of these systems. The experimental techniques that were employed in the present studies are: Laser light scattering, small-angle X-ray scattering(SAXS) measurements and visual observations. The eoexistence surface of the system E + W + AS was determined by visual observations. Laser light scattering measurements were conducted to study the critical behavior of osmotic susceptibility (xr) of E + W + As, whereas SAXS studies were conducted to ascertain the existence, and quantify the spatial extent of the additional length scale in the two systems investigated. The main objectives of this research were: (i) to study the phase behavior of the ternary mixture E + W + AS at atmospheric pressure; (ii) to check the existence of crossover from 3-D Ising to mean-field critical behavior while moving away from Tc in this system; (iii) to determine the nature (monotonic or nonmonotonic) of crossover; (iv) to provide some insight into the origin of this crossover behavior in terms of an additional length scale characteristic of the system; (v) to understand the evolution of the critical behavior in the proximity of CDP, and DCP; (vi) to experimentally realize the CIP; and (vii) to investigate the presence of solvent-induced conformational changes in conducting polymer.

The object of this thesis was to study plant community structure, especially in relation to vertebrate herbivory, in an altitudinal gradient in the Fennoscandian mountain chain. A sowing experiment in a high alpine Ranunculus glacialis population showed that seeds germinated better in cleared microsites than under established individuals. This is contrasted with a hypothesis that predicts positive plant-plant interactions in high alpine environments. It was concluded that plant-plant interactions in die studied population varied from neutral to negative, whereas no indications for positive interactions were found. An exclosure experiment in a snow-bed showed that a lemming population consumed 33 % of the available graminoids and 66 % of the mosses from August to June during a population peak. The results shows that grazing needs to be considered as a structuring factor in snow-bed vegetation. The vegetation in exclosures in another snow-bed changed from a graminoid-dominated to a herb-dominated plant community during a long-term (six years) experiment No changes of the same magnitude were seen in a tall herb meadow on a lower altitude. Survival of transplanted adult shoots from the tall herb meadow was equally high in the snow-bed as on the meadow, and germination was also high on bare ground in the snow-bed. Grazing seemed to be a more important structuring factor in the snow-bed than in the more productive tall herb meadow. Raising the grazing pressure during one growing season by introducing microtine rodents into enclosures did not cause any large short-term effects on plant community structure in a tall hob meadow or in a snow-bed. Marked shoots showed that some preferred plant species had a high shoot mortality, but biomass for pooled categories of plants was not significantly affected. It was predicted that the tall herb meadow would be more grazing sensitive than die snow-bed, but productivity on the meadow seemed to be sufficiently high for the plants to compensate for the grazing during the growing season. A greenhouse experiment showed that voles, when grazing freely, have the potential to deplete productive field layer vegetation contrary to predictions from plant defence theories. A nitrogen-based defence did not prevent heavy shoot mortality for toxic tall herbs. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 5 uppsatser.</p> / digitalisering@umu.se