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Le Grand Ecosystème Marin du Courant des Canaries est un des principaux systèmes mondiaux d’upwelling et assure une des plus importantes productions de pêche parmi les grands écosystèmes marins d’Afrique. Cet écosystème est soumis à des apports en éléments métalliques entraînant leur accumulation par les organismes marins et notamment les poissons. En termes de bioaccumulation, une forte variabilité est observée entre les espèces exploitées mais également entre individus d’une même espèce. Ce travail de thèse se propose de caractériser les paramètres majeurs qui déterminent l’accumulation des métaux par les poissons marins, en prenant pour cas d’étude l’écosystème du courant des Canaries. Deux approches ont été adoptées, l’une portant sur les particularités physiologiques et l’autre sur les mécanismes écologiques régissant la bioaccumulation. A un premier niveau d’intégration, les caractéristiques physiologiques spécifiques telles que l’efficacité d’assimilation, les concentrations en métallothionéines et le mode de séquestration des métaux agissent sur la bioaccumulation. Ensuite, à un second niveau, la nature des proies joue un rôle crucial sur l’exposition aux métaux du fait de la dominance de la voie de transfert trophique chez les poissons marins. A un dernier niveau d’intégration, l’habitat représente un paramètre déterminant, principalement en influant sur les niveaux de contamination des proies soumis au cycle des métaux dans l’environnement marin. Cette thèse a présenté une approche innovante, en proposant une étude intégrée de la cellule à l’écosystème en passant par l’individu, dédiée à la compréhension d’un mécanisme impliquant des répercutions tant sur la préservation des ressources marines que sur la santé des consommateurs. / The Canary Current Large Marine Ecosystem in West Africa is one of the most productive upwelling ecosystems. It is subjected to anthropogenic inputs leading to metal accumulation by marine fish species, which show a great variability in terms of metal concentrations. This PhD work aims to characterize the major parameters determining metal accumulation by marine fish, based on the case study of the Canary current. Two main approaches were developed concerning physiological and ecological features. At a first integration level, physiological characteristics such as assimilation efficiency, metallothionein concentrations and subcellular metal partitioning influence bioaccumulation. At a second level, prey composition plays a key role due to the dominance of metal accumulation through dietary intakes in marine fish. Finally, habitat drives metal exposure to fish due to the biogeochemical cycle of the metal elements.This study proposed an innovating approach, combining analyses from the cellular level to the ecosystem one, including the individual level, and aiming for a thorough comprehension of a mechanism implying consequences on marine resource conservation and human safety.

Univerzita Karlova v Praze Přírodovědecká fakulta Studijní program: Molekulární biologie, genetika a virologie Bc. Jan Röslein Mutační a substituční tempo u sexuálních a klonáních forem: možný klíč k vysvětlení persistence sexu u modelové skupiny sekavců Mutation AND substitution rates in sexual and asexual forms: a clue to the persistence of sex in a model group of Cobitis? Typ závěrečné práce Diplomová Vedoucí závěrečné práce: Mgr. Karel Janko, Ph.D. Praha, 2015 Velký dík náleží mému školiteli Mgr. Karlu Jankovi, Ph.D. za velmi nápomocné, direktivní vedení práce. Též bych rád poděkoval panu Mgr. Janu Pačesovi, Ph.D. za více než vzdělávací rozměr v oblasti bioinformatické analýzy a Mgr. Ladislavu Pekárikovi, Ph.D., Mgr. Janu Kočímu za pomoc při analýze vybraných kapitol. Také bych rád poděkoval rodině za podporu. Všem participantům na této diplomové práci se hluboce omlouvám za způsobenou psychickou újmu. Prohlášení: Prohlašuji, že jsem závěrečnou práci zpracoval/a samostatně a že jsem uvedl/a všechny použité informační zdroje a literaturu. Tato práce ani její podstatná část nebyla předložena k získání jiného nebo stejného akademického titulu. V Praze dne 12. 8. 2015 Podpis: Abstrakt Klíčová slova: Abstract Key words: Obsah 1...

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[...] L’objectif decette thèse est l’étude des mécanismes modulant la biodisponibilité des métaux pour l’escargotCantareus aspersus (syn. Helix aspersa), invertébré vivant à l’interface sol‐plante‐air (maillonintermédiaire, saprophage, phytophage, de chaînes alimentaires). La biodisponibilité est principalementévaluée ici en mesurant l’accumulation (concentrations internes en métaux après 28 jours d’exposition) etles flux d’assimilation. L’influence de paramètres édaphiques sur la disponibilité et la biodisponibilité desmétaux des sols et la contribution des sources de contamination (sols/plantes) des escargots constituentles variables étudiées dans deux conditions d'exposition :[...] L’ensemble des résultats souligne la nécessité de prendre en compte les facteurs et lesmécanismes qui modulent la biodisponibilité des métaux pour modéliser au mieux leur accumulation etleur assimilation par les escargots. Aucune méthode chimique unique d’estimation de la biodisponibilitédes métaux n’ayant pu être déterminée, nous préconisons l’utilisation de mesures biologiques quireflètent mieux la réelle biodisponibilité. / [...] The aim of this thesis is to study the mechanisms that modulate metal bioavailabilityfor the garden snail Cantareus aspersus (= Helix aspersa) a soil invertebrate living at the interfacesoil‐plant‐air (saprophagous and phytophagous intermediate link in the food chain).[...] These data underline the necessity to take into account the factors and mechanisms that modulate themetal bioavailability for snails to better model accumulation and assimilation of metal by snails. As nounique chemical method to assess metal bioavailability was determined, we recommend the use ofbiological measures that identify the real metal bioavailability rather than the use of chemical measures.

Master of Science / Department of Agronomy / Jay M. Ham / The potential environmental impact of animal feeding operations on air quality has created the need for accurate air emissions measurements. Of particular concern are ammonia emissions from cattle feedlots, operations that contribute a large portion of the agricultural ammonia emissions inventory. Micrometeorological methods are ideal for emissions measurements from large, open-source areas like feedlot pens; however, theoretical assumptions about the boundary layer must be made, which may not hold true above the heterogeneous, fetch-limited surface of the feedlot. Thus, the first objective of this work was to characterize the surface boundary layer of an open-air cattle feedlot and provide insight into how micrometeorological techniques might be applied to these non-ideal sites. Eddy covariance was used to measure fluxes of momentum, heat, water, and carbon dioxide from a commercial cattle feedlot in central Kansas. Data supported the use of eddy covariance and similar methods (i.e., relaxed eddy accumulation) for flux measurements from both cattle and pen surfaces. The modeled cumulative source area contributing to eddy covariance measurements at a 6 m sample height was dominated by just a few pens near the tower, making the characteristics of those pens especially important when interpreting results. The second objective was to develop a system for measuring ammonia fluxes from feedlots. A new type of relaxed eddy accumulation system was designed, fabricated, and tested that used honeycomb denuders to independently sample ammonia in up-moving and down-moving eddies. Field testing of the relaxed eddy accumulation system at a feedlot near Manhattan, KS showed fluxes of ammonia ranged between 60 and 130 μg m-2 s-1 during the summer of 2007. Even in the high ammonia environment (e.g., 300-600 μg m-3), the honeycomb denuders had enough capacity for the 4-hour sampling duration and could be used to measure other chemical species that the denuders could be configured to capture. Results provide a foundation for emissions measurements of ammonia and other gases at cattle feedlots and help address some of the challenges that micrometeorologists face with any non-ideal source area.

Magister Scientiae (Biodiversity and Conservation Biology) / Fog and dew interception and utilization by plant canopies remains one of the least considered aspects of vegetation studies at any scale yet the few studies that have been conducted point to their considerable influence on ecological processes and a critical role in modulating climate in southern African arid ecosystems. Their relevance to succulent plant hydrology was investigated in this study.The first study measured stable 18O and 2H isotope ratios in samples of rain, fog and dew water and compared these with those assayed monthly in stem xylem water of six succulent shrub species over a one year period. Negative 18O and 2H ratios were observed in the stem xylem water of all six species signifying a predominance of water derived from fog and dew precipitation which was most conspicuous during the wet winter. This implied that fog and dew are even more important sources of water than rain and corroborated by significant correspondence found between fog and dew frequencies, succulent foliar water contents and quantum yields of photochemistry.The second study monitored variations in stem diameter at 2-hourly intervals in 8 succulent shrub species of diverse growth form over a 9-month period. Two groups of species were distinguished based on whether their daily amplitudes in stem diameter were consistently positively correlated with daily fluxes in vapour pressure deficit, which were indicative of a persistent CAM photosynthetic mode, or intermittently correlated with daily fluxes in vapour pressure deficit, which were indicative of mixed CAM and C3 photosynthetic modes. Among species displaying a persistent CAM photosynthetic mode, high nocturnal fog and dew precipitation amounts corresponded with low daily amplitudes in stem diameter, and vice versa, which pointed to reduced nocturnal stomatal water loss. These patterns, which were indistinct among species displaying mixed CAM and C3 photosynthetic modes, were corroborated by small daily amplitudes in stem diameter also consistently observed in one species displaying a CAM photosynthetic mode in ambient than artificially fog and dew excluded environments.The third study monitored changes in water mass at hourly intervals of quartz gravel substrates with different dwarf succulent species assemblages over an 8-month period.Consistently greater net amounts of water were intercepted daily by quartz gravel substrates containing Agyroderma pearsonii than Cephalophylum spissum plants as well as those without plants. These attributed to a high water repellence of A. pearsonii leaves and less radiation absorbed by the paler silvery to grey-green leaves of A. pearsonii leaves than the dark green leaves of C. spissum resulting in lower leaf temperatures and less water loss by transpiration. Quartz gravel soils devoid of plants intercepted nearly 5-times greater amounts of precipitation contributed by fog and dew than that contributed by rain. These precipitation amounts exceeding the high percentages of total hydrological input contributed by fog and dew reported in other ecosystems.The study concludes that fog and dew are a vital source of water for succulent shrubs in arid South African ecosystems and imply that diminished fog and dew frequencies associated with elevated night time temperatures accompanying global warming could exacerbate plant drought stress.

La thèse concerne les modèles de l'écoulement dans les milieux fracturés multiéchelles qui prouvent l'effet de mémoire à chaque échelle. Les processus analysés dans ces milieux est auto-similaire. Nous avons analysé l'équation de diffusion à toutes les échelles et appliqué la méthode d'homogénéisation asymptotique avec l'objectif de construire le modèle macroscopique moyenne sur toutes les échelles d'hétérogénéité. Un système fermé des équations récursives pour les noyaux d’échange effectif est obtenu. La solution analytico-numérique de ce système est développé. Nous avons montré une convergence des résultats obtenus pour le nombre des différentes échelles d'un comportement limite stable. Le problème limite pour les noyaux est obtenus pour un nombre relativement élevé d'échelles. En plus, nous avons analysé l'écoulement dans une immergée dans le réservoir poreux à différents nombres de Reynolds. Les équations de Navier-Stokes sont résolu par la méthode asymptotique à deux échelles avec l'objectif d'obtenir l'équation de la moyenne sur l'ouverture de fracture en présence d'afflux à travers les limites et pour la géométrie irrégulière des murs. / The thesis concerns the models of flow in multiscale fractured media which prove the memory effect at each scale. The analyzed process in these media is self-similar. The necessary and sufficient condition of self-similarity has been proposed so that it is possible to analyze the behavior of media for any number of scales. We analyzed the diffusion equation at each scale and applied the asymptotic homogenization method with the objective to construct the macroscopic model averaged over all scales of heterogeneity. A system of closed recurrent equations for the effective exchange kernels was obtained. The procedure of analytico-numerical solution of this system was developed. We showed a convergence of the results obtained for various numbers of scales to a stable limit behavior. The limit problem for the effective kernels from the recurrent equations obtained for a relatively large number of scales. In addition we analyzed the flow in a single fracture and circular channel immersed in porous reservoir at various Reynolds numbers. The Navier-Stokes equations was solved by the method of two-scale asymptotic method with the objective to obtain the flow equation averaged over the fracture aperture in the presence of inflow through the limits and irregular geometry of walls.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-19T14:05:45Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Versão Biblioteca.New.pdf: 8228465 bytes, checksum: 555e31ae83e9955c8ba2d9d9fc24b9ae (MD5) / Made available in DSpace on 2016-04-19T14:05:45Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Versão Biblioteca.New.pdf: 8228465 bytes, checksum: 555e31ae83e9955c8ba2d9d9fc24b9ae (MD5) Previous issue date: 2015-08-18 / FACEPE / Grandes empresas e grupos econômicos, dentro do atual processo de reprodução ampliada do capital e de seu regime de acumulação com dominância da valorização financeira, requerem, cada vez mais, grandes negócios (megaprojetos, megaeventos), e esses só são viáveis em parceria com o Estado. Esta relação, com o tempo, torna-se mais complexa e envolve uma série de inovações em arranjos político-institucionais e espaciais. Assim, questionou-se se grandes obras ligadas à reestruturação do espaço metropolitano implementadas na Região Metropolitana do Recife - RMR podiam ser consideradas expressões de uma acumulação rentista-patrimonial ampliada entre o Estado e diferentes frações do capital, amplificando a unidade contraditória entre fixos e fluxos própria da reprodução do capital contemporâneo. Para responder a essa, questão buscou-se demonstrar as ações do Estado e o seu papel na concentração e centralização do capital nas mãos de oligarquias econômicas, neste caso, grupos econômicos nacionais ligados à produção do espaço (construção civil) e ao capital financeiro, e em assegurar importantes condições econômicas e extraeconômicas para a acumulação, com o uso dos fundos públicos, créditos subsidiados, incentivos fiscais, terras entre outros. Identificou-se que setores como o da construção civil ganham com o crescimento da economia nacional que leva à busca por investimentos em capital fixo, que também ocorre em períodos de crises econômicas do sistema capitalista. Optou-se por uma pesquisa do tipo qualitativa, explicativa, documental e bibliográfica. Fundamenta-se aqui na compreensão de que urbanização, modernização, política econômica e o planejamento são realidades sociais, e que toda realidade social é espacial e historicamente determinada. Na organização da exposição da tese, optou-se por seguir o método regressivo-progressivo de H. Lefebvre. Entende-se, nesta pesquisa, que os grandes negócios da produção do espaço têm como principais beneficiados as grandes empreiteiras “As Campeãs Nacionais”. Analisaram-se os grandes projetos: Cidade da Copa/Arena Itaipava; Rota dos Coqueiros e Cidade Saneada como representativos de uma “nova” articulação entre o público e o privado dentro do processo chamado por nós de acumulação rentista-patrimonial ampliada entre Estado e capital. Assim, o estudo focou-se na reestruturação econômica e espacial da RMR ligadas a esses projetos e concluiu que este processo é produto da concorrência global capitalista agora movida por um amplo processo de financeirização da economia mundial, fruto de um ajuste espaço temporal do sistema e sua ligação com a produção do espaço, e também representa uma coalizão de interesses entre frações do capital nacionais e locais representantes de grupos econômicos ligados ao setor da construção civil, via arranjos político-institucionais e espaciais como concessões e parcerias público-privadas, financiamentos de longo prazo e participações no capital social de um número seleto de empresas do setor da construção pesada ligadas a grandes holdings nacionais, agentes esses capazes de manipular o fundo público via poder político e econômico, dentro de um contexto de imbricação de escalas geográficas. / Major companies and economic groups, within the current expanded reproduction process of the capital and its accumulation regime with dominance of financial valuation, require, increasingly, major business (mega projects, mega-events), and those can only be feasible in partnership with the State. This relationship, over time, becomes more complex and includes a number of innovations in political-institutional and spatial arrangements. Thus, the question has been raised as to whether great works connected to the restructuring process of the metropolitan space implemented in the Metropolitan Region of Recife – MRR could be considered as expressions of an expanded patrimonial rentier accumulation among the State and different fractions of the capital, amplifying the contradictory unity between ‘’fix and flows’’ peculiar of the reproduction of the contemporary capital. To solve this question efforts have been made to demonstrate the actions of the State and its role regarding the concentration and centralization of the capital in the hands of economic oligarchies, in this case, national economic groups connected to space production (building construction) and to the financial capital, and to assure important economic and extra-economic conditions for accumulation, using public funds, subsidized credit, tax incentives, lands and others. It has been identified that sectors such as building construction gain from the growth of the national economy, leading to the search for investments in fixed capital, which also occurs in times of economic crises of the capitalist system. It has been chosen a qualitative, explanatory, documentary and bibliographic type of research. It is based here on the understanding that urbanization, modernization, economic policy and planning are social realities, and that all social reality is spatially and historically determined. In the organization of the thesis exhibition it was chosen to follow the regressive-progressive method of H. Lefebvre. It is understood in this research that the big businesses of production of the space have as main beneficiaries the great contractors "The National Champions". The major projects have been analyzed: The Cup City/Itaipava Arena; Rota dos Coqueiros e Cidade Saneada as representative of a ‘’new’’ articulation between public and private within the process which we call expanded patrimonial rentier accumulation between State and capital. Thus, the study focused on the economic and spatial restructuring of the MRR linked to those projects and concluded that this process is the result of global capitalist competition now driven by a broad process of financialization of the world economy, result of an space-time adjustment of the system and its link with the production of the space, and also represents a coalition of interests among national and local fractions of the capital which represent economic groups connected to the construction industry, via political-institutional and spatial arrangements such as concessions and public-private partnerships, long-term debt and shares in the social capital of a select number of companies from the heavy construction sector linked to great national holdings, being those agents able to manipulate the public fund via political and economic influence, in an overlay context of geographic scales.

En Latinoamérica, la gobernanza del agua se enfrenta con el problema del aumento de la demanda de recursos hídricos, la creciente variabilidad hidrológica en un contexto de cambio climático, y la contaminación que sigue proliferándose. Por lo tanto, se observa una creciente escasez de agua, en cantidad y calidad, generando competencia y conflictos entre los actores involucrados. El problema coincide con el urgente temario internacional de la concentración de tierra, que está muy entrelazado con la concentración del agua en pocas manos. La globalización y un clima político neoliberal facilitan que actores poderosos acumulen derechos y volúmenes de agua a expensas de usuarios de menor poder. Este documento tiene por objetivo examinar el contexto nacional poniendo atención especial en la acumulación en casos ejemplares de la costa peruana. Se basa en revisión de literatura, informes y archivos pertinentes. Concluye que la distribución injusta de tierra y agua, a expensas de familias rurales y de territorios comunales e indígenas, constituye una grave amenaza para la sostenibilidad ambiental, la seguridad hídrica y la seguridad alimentaria. / In Latin America, water governance is facing the problem of rising demand for water resources, increased hydrological variability in a context of climate change, proliferating contamination and thus —in general— increasing scarcity of water in terms of quantity, quality, and opportunity. This creates competition and conflicts among stakeholders. The issue coincides with the urgent international problem of concentration of land, which is heavily intertwined with the concentration of water in the hands of the few. Globalization and a neoliberal political climate facilitate that powerful actors accumulate water rights and volumes at the expense of less powerful water users. This paper examines some exemplary situations in Peru. It is based on literature review, reports and archival research. The paper concludes that the unfair distribution of land and water, at the expense of rural families, communities and indigenous territories, constitutes a serious threat to environmental sustainability, water security and food security.