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Ramondenc, Simon. "Analyse des variations spatio-temporelles du zooplancton gélatineux et son effet sur les flux de matières à l'aide d'une approche combinant expérimentation et écologie numérique." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066528/document.
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Le terme plancton désigne l'ensemble des organismes dérivant au grès des courants marins. On distingue le plancton végétal et principalement photosynthétique, "le phytoplancton", du plancton animal hétérotrophe, "le zooplancton". Au cours des dernières décennies, de nombreuses études ont documenté une croissance de l'abondance et de la distribution spatiale du zooplancton gélatineux à travers diverses régions. Même si le terme "gélification" des océans doit être utilisé avec beaucoup de précaution, des régions comme la mer Méditerranée montre une constante augmentation des méduses au cours de ces 40 dernières années. L'espèce Pelagia noctiluca (Forsskål, 1775) est considérée comme étant la méduse la plus abondante du bassin méditerranéen depuis les années 70. Du fait de leur présence massive dans cette région, il est primordial d'évaluer précisément l'impact de P. noctiluca à la fois sur les cycles biogéochimiques et sur la structuration des écosystèmes pélagiques. Pour cela, les deux processus majeurs de transfert de matière dans l'écosystème doivent être étudiés : la séquestration de carbone via la pompe biologique et le transfert de carbon au travers des réseaux trophiques. Cette thèse s'articule autour de trois axes majeurs: (i) réaliser un premier bilan de l'export de carbone organique particulaire (POCtotal) et dissous (DOC) en mer Méditerranée, (ii) construire un modèle écophysiologique de P. noctiluca pour déterminer la contribution de cette méduse à la pompe biologique, et (iii) évaluer le niveau trophique de P. noctiluca et son potentiel impact sur les niveaux trophiques inférieursThe term “plankton” refers to all the organisms drifting in the water following the currents. Commonly, the vegetable autotrophic and mainly photosynthetic, “phytoplankton” is distinguished from the heterotrophic and animal “zooplankton”. In the last decades, many studies reported an increase in the abundances and spatial distributions of gelatinous zooplankton in many oceans. Even if the concept of “jellyfication of the oceans” needs to be used with caution, jellyfish populations show an increase in Mediterranean Sea over the last 40 years. The species Pelagia noctiluca (Forsskål, 1775) is considered as the most abundant jellyfish in the Mediterranean basin since the 70s. Due to its massive presence in this area, it is essential to evaluate precisely the impact of P. noctiluca on both biogeochemical cycles and pelagic ecosystem structure. Thus, the contribution of P. noctiluca to the two main factors regulating the biological carbon transfer in the oceans: carbon sequestration via the biological carbon pump and carbon transfer through trophic networks. This manuscript is divided in 3 main sections : (i) providing an initial budget of the particulate (POCtotal) and dissolved organic carbon (DOC) in the Mediterranean sea, (ii) building an ecophysiological model of P. noctiluca to estimate its contribution to the biological carbon pump, and (iii) assessing the trophic level of P. noctiluca and its potential impact on lower trophic levels
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Moulins, Aurélie. "To the integrated approach and to the management of pelagic biodiversity inside a marine protected area : case of the cetacean populations in the Pelagos sanctuary (north-western Mediterranean sea)." Lyon 1, 2008. http://www.theses.fr/2008LYO10027.
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Zajková, Zuzana. "Movement ecology in pelagic seabirds." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/668688.
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Movement is a fundamental component of behaviour and thus both are inextricably linked. Variation in movement patterns usually reflects different behaviours, including those most glaring, such as foraging, dispersal, migration, social interaction, mate search or escaping from predators. The way individuals allocate their time budget to different behaviours within circadian rhythm and over the annual life cycle will ultimately provide knowledge about evolutionary processes and adaptive capacity, also important to proper conservation actions of endangered species. Among highly mobile marine megafauna, seabirds represent suitable model species to address key questions about movement and behaviour. The study of year-round movements of seabirds has been addressed over the last 20 years with the wide deployment of light-level geolocators equipped with saltwater immersion sensors. However, wet-dry data provided by such loggers seem underused so far despite their usefulness to provide important insights on a variety of dimensions of seabird ecology. The main aim of this thesis was to provide new insights into the factors shaping seabird behaviour. The thesis encompasses several aspects of seabird at-sea ecology of 4 different species spread over the Atlantic Ocean: Boyd’s shearwater (Puffinus boydi), Common tern (Sterna hirundo), Atlantic petrel (Pterodroma incerta) and Cory’s shearwater (Calonectris borealis). In Chapter 1 we reveal the timing of major events over the annual life cycle, migratory routes and place on the map the non-breeding areas of a little-known tropical seabird endemic to Cape Verde Islands, the Boyd’s Shearwater. We show that Boyd's shearwaters
perform longitudinal migrations to the oligotrophic central North Atlantic Ocean for the non-breeding season, in contrast with closely-related taxa that rely on most productive waters. In Chapter 2, we show that Common terns breeding in continental Europe spread over the West African coast for wintering, but females winter further north and use offshore waters whereas males winter further south and remain nearby the coastline. Behavioural budgets of Common terns were shaped within circadian and circa-annual rhythms. In Chapter 3 we describe in detail the phenology of the Atlantic petrel, showing that breeding success likely shapes the timing of major life-history events and behavioural patterns year round. We did find evidence of carry-over effects, since failed breeders advanced their post-breeding migration, remained longer in the wintering area, and advanced pre-breeding migration comparing to successful breeders. Breeding success did not affect the selection of wintering areas, as all birds relied on the South American shelf slope during different stages of the annual cycle. In Chapter 4, we demonstrate how geolocator-immersion loggers constitute a powerful and irreplaceable source of information to study seabird behaviour. We present a novel approach to infer a diverse array of behaviours based uniquely on wet-dry data, built upon a set of state-of-the-art unsupervised machine learning algorithms that reduce multidimensional data to a bidimensional behavioural space, from which different behaviours can be drawn. We applied the protocol on wet-dry data from Cory’s shearwater. Through these means, we can inspect in great detail and from manifold perspectives the behavioural patterns at individual and population level, highlighting how seasonal constraints shape
behavioural budgets and behavioural strategies. We use data visualization tools such as actograms and behavioural landscapes to get new insights, highlighting that such tools constitute an effective method to visualize behaviour of seabirds inferred from wet-dry data from manifold perspectives. Geolocator-immersion sensors currently remain as the most cost-effective balanced tracking devices to track seabird species over the entire annual cycle while ensuring the welfare of tagged individuals. Thus, results compiled in this thesis should encourage researchers to incorporate the use wet-dry data within hypothesis-driven frameworks, which surely would contribute to increase our knowledge of seabird ecology at sea.El movimiento es un componente fundamental del comportamiento animal, estando ambos íntimamente entrelazados. Variaciones en los patrones de movimiento normalmente reflejan cambios de comportamiento, incluyendo aquellos más conspicuos como la búsqueda de alimento, la dispersión, la migración, las interacciones sociales, la búsqueda de pareja o la huida ante depredadores. La forma en la que los patrones comportamentales se ajustan en el tiempo de acuerdo a los ritmos circadianos y a lo largo del ciclo anual puede ayudarnos a entender, en última instancia, los procesos evolutivos y la capacidad de adaptación de las poblaciones animales, algo también importante de cara al desarrollo de medidas de conservación de especies amenazadas. Las aves marinas representan un modelo especialmente adecuado para el estudio de la ecología comportamental y del movimiento. Estudiar los movimientos de las aves marinas en mar abierto ha sido posible en las dos últimas décadas gracias a la normalización en el uso de geolocalizadores por niveles de luz. Aunque buena parte de los modelos de geolocalizador es capaz de registrar datos de conductividad en agua salada (seco/húmedo), esta información parece infrautilizada a la luz de la literatura publicada. Sin embargo, los datos de conductividad son enormemente útiles para el estudio de multitud de aspectos sobre la ecología de las aves marinas. Esta tesis aborda diferentes aspectos de la ecología en mar abierto de 4 especies de aves marinas del océano Atlántico: la pardela chica de Cabo Verde (Puffinus boydi), el charrán común (Sterna hirundo), el petrel atlántico (Pterodroma incerta) y la pardela cenicienta (Calonectris borealis). En el Capítulo 1 revelamos la fenología, rutas migratorias y área de invernada de una especie tropical de pequeño tamaño, la pardela de Cabo Verde, endémica de dicho archipiélago. A diferencia de especies cercanas, los individuos de esta especie realizan una migración longitudinal hasta las aguas oligotróficas del centro del Atlántico Norte. En el Capítulo 2, mostramos que los charranes comunes que crían en Europa migran hasta la costa oeste de África para invernar, aunque las hembras se quedan más al norte y en ambientes más marinos, y los machos más al sur y en ambientes costeros. El comportamiento en ambos sexos parece regulado por ritmos circadianos y anuales. En el Capítulo 3, desgranamos la fenología del petrel Atlántico, una especie endémica del archipiélago de Tristán da Cunha, mostrando que el éxito reproductor probablemente moldea la sucesión de eventos fenológicos y los patrones de comportamiento. Incluso encontramos evidencias de efectos arrastrados, puesto que los animales que fracasaron en la cría adelantaron la migración, permanecieron más tiempo en la zona de invernada, y retornaron antes a las colonias de cría. Tanto los animales que tuvieron éxito como los que fracasaron en la cría invernaron en aguas de la plataforma continental de América del Sur y Patagonia. En el Capítulo 4, presentamos un nuevo protocolo analítico basado en algoritmos de aprendizaje automático que utiliza únicamente datos de conductividad. Mediante su aplicación sobre datos de pardelas cenicientas, demostramos que los datos de conductividad constituyen una poderosa herramienta para el estudio de las aves marinas, permitiendo desglosar a un nivel sin precedentes su comportamiento a diversas escalas: espacial (de viajes cortos a migraciones anuales), temporal (de días a años) y poblacional (de individuos a poblaciones). El análisis también nos permite resaltar los diferentes elementos que moldean el comportamiento animal a diferentes escalas temporales, utilizando para ellos potentes herramientas de visualización de datos como los actogramas. El conjunto de resultados expuestos en esta tesis debe alentar a los investigadores a utilizar más frecuentemente los datos de conductividad, lo cual contribuiría a aumentar nuestro conocimiento sobre la ecología de las aves marinas.
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De, Schryver Vera. "Mixotrophy and pelagic ecosystem dynamics." Thesis, Brest, 2013. http://www.theses.fr/2013BRES0045/document.
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Les espèces protistes ont été traditionnellement classifiées comme des plantes ou des animaux en raison de l’absence ou présence des chloroplastes. L’état actuel de la connaissance indique qu’un grand nombre d’espèces protistes portent des chloroplastes mais que physiologiquement elles sont capables d’utiliser l’autotrophie (photosynthèse) ou l’hétérotrophie pour se nourrir. La combinaison de ces deux modes trophiques par une même cellule est nommée mixotrophie. Chez les protistes l’hétérotrophie peut s’effectuer soit par la consommation des particules par phagocytose, e.g. des proies bactériennes, ou bien par l’absorption des composants organiques dissouts, i.e. osmotrophie. La mixotrophie est de plus en plus décrit chez les protistes dans tous les habitats aquatiques. Les écologistes du plancton constatent la récurrence de la mixotrophie chez les formes traditionnelles « phyto»plancton et micro »zoo »plancton. Cependant, identifier et quantifier la mixotrophie reste toujours un défi méthodologique. Dans cette étude nous nous sommes intéressés à la mixotrophie chez les espèces phytoplanctoniques marines, en particulier à leur nutrition phagotrophique de proies bactériennes. Nous avons testé des techniques modernes afin d’identifier la mixotrophie dans des cellules phytoplanctoniques. La technique cytogénétique d’hybridation in situ Card-FISH en utilisant de sondes d’ARN ribosomique 16S a été effectuée suivant des protocoles existant pour des bactéries et des protistes. Cette technique s’est avérée être un outil précieux pour visualiser des groupes phylogénétiques bactériens en association avec le phytoplancton à l’aide de la microscopie à épifluorescence, sans avoir besoin d'un isolement préalable des cellules ou des interférences avec l'association microbienne. Cependant, la méthode a échoué pour visualiser mixotrophie chez le phytoplancton car la sonde eubactérienne générale(EUB338) combine une large gamme d'espèces phytoplanctoniques, ce qui rend impossible de discriminer les signaux fluorescents provenant de tissus bactérienne ou phytoplanctonique. Le contexte de ces études est le phytoplancton et les bactéries hétérotrophes lesquels constituent des principaux concurrents pour les nutriments inorganiques dissouts. Dans le cas où la croissance bactérienne est limitée par le carbone, l'augmentation de la concentration de carbone organique dissous(DOC) renforce la croissance bactérienne et la consommation de nutriments dissous et ainsi affecte négativement la croissance du phytoplancton autotrophe. Cependant, les consommateurs de bactéries, i.e.phytoflagellés mixotrophes, peuvent être favorisés dans de telles situations car la hausse de DOC donne lieu à l'abondance plus élevé des proies bactériennes.En outre, nos résultats indiquent un potentiel effet positif de la température sur le mode de nutrition hétérotrophe de l’espèce, ainsi qu’une croissante contribution des espèces mixotrophes au sein des communautés de phytoplancton dans des conditions des hautes températures des eaux de surface de la merProtist species were traditionally classified morphologically as either „plants“ or „animals“, based on the absence or presence of chloroplasts. State of science is that a high number of protist species carrychloroplasts but are nutritionally able to employ both autotrophy (photosynthesis) and heterotrophywithin a single cell. This combination of autotrophic and heterotrophic mode of nutrition within a single species is named mixotrophy. In protists, heterotrophy can be realized either by the uptake of food particles (e.g. bacterial prey) through phagocytosis or by the uptake of dissolved organic compounds (i.e.osmotrophy). Mixotrophy is globally and increasingly described in protists from all types of aquatic habitats. Plankton ecologists nowadays assess mixotrophy among the traditionally typified “phyto”plankton and mikro”zoo”plankton species as regularity. Nevertheless, detection and quantification of mixotrophy is still a methodological challenge. In this study, we focused on mixotrophy in marine phytoplankton species and put emphasis on its phagotrophic nutrition from heterotrophic bacterial prey. State of the art methodology was tested to visualize mixotrophy in single phytoplankton cells. Catalyzedreported deposition-fluorescence in situ hybridization (Card-FISH), using 16S ribosomal RNA probes,was employed based on existing protocols for bacteria and protists. The method proved to be a valuable tool to visualise bacterial phylogenetic groups in association with phytoplankton by epifluorescence microscopy without need for prior isolation of cells or interference with the microbial association.However, the method failed to visualize mixotrophy in phytoplankton since the general eubacterial probe(EUB338) hybridised a broad range of phytoplankton species making it impossible to discriminate fluorescent signals originating from bacterial or phytoplankton tissue. Background of these studies is phytoplankton and heterotrophic bacteria being major competitors for dissolved inorganic nutrients. In case that bacterial growth is carbon limited, increasing concentrations of degradable dissolved organic carbon (DOC) enhance bacterial growth and consumption of dissolved nutrients and there by negatively affect autotrophic phytoplankton growth. Bacteria consuming mixotrophic phytoflagellates, however, may gain in importance in such situations since DOC provokes higher bacterial prey supply.In addition, our results indicate a potential positive effect of temperature on O. minima´s heterotrophic nutrition mode, and indicate a potential increasing contribution of mixotrophic species to phytoplankton communities under increasing sea surface water temperatures
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Wattimena, Stephen. "Couplage pelagos-benthos en Manche occidentale." Brest, 2000. http://www.theses.fr/2000BRESA001.
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Wilson, Rory Paul. "Breeding Jackass Penguins as pelagic predators." Doctoral thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/17653.
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Bibliography: pages 187-191.The foraging of breeding Jackass Penguins Spheniscus demersus was studied in and around southwestern Cape Province, Saldanha Bay (33⁰ S, 18⁰ E), South Africa. Penguins are difficult to observe at sea. Hence, I devised a number of new techniques for studying the foraging behaviour of Jackass Penguins at sea. I built electronic and autoradiographic remote-sensing devices to measure swimming speed, distance travelled and time spent at each depth by foraging Jackass Penguins. Penguin swimming speed was reduced in proportion to the cross-sectional area of the devices, and results derived from birds wearing the devices had to be interpreted accordingly. Penguins do not regurgitate their stomach contents when handled, so I constructed a wet-offloading stomach pump which extracted 100% of the stomach contents. Using this pump, I determined that the rate of digestion of fish and squid by Jackass Penguins differed. Care is needed in diet interpretations where both fish and squid are major food items.
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Williams, Maria C. "The pelagic record of ocean acidification." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686814.
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Ocean acidification (OA) as a result of anthropogenic CO2 accumulation has major implications for the calcification of marine organisms. Assessing the calcification response of coccolithophores and planktic foraminifera to OA in particular is paramount as together they produce the majority of pelagic carbonate burial and thus impact biogeochemical cycling and oceanic CO2 uptake. In this thesis, two sediment cores from Eirik Drift and the Norwegian Sea are used to reconstruct the natural calcification response of marine plankton since the Last Glacial Maximum and compare these changes to recent anthropogenic influences over the last 200 years. Reconstructions of the bottom water dynamics and thus sedimentation at Eirik Drift infers the suitability of the core for palaeo-analysis of plankton calcification. The calcification response of three foraminiferal species and two morphotypes of the dominant polar species Neogloboquadrina pachyderma are significantly correlated throughout the Holocene suggesting similar calcification mechanisms between and within species. Although the drivers of calcification appear to vary temporally and geographically, down-core planktic foraminiferal Mg/Ca and faunal assemblage counts point towards the importance of sea surface temperature and optimal growth conditions on the calcification of N pachyderma. Unlike Globigerina bulloides, N pachyderma shows little sensitivity to CO2 changes across the last deglaciation Since the beginning of industrialisation, foraminiferal calcification fluctuates within the natural long-term trends observed over the last 22 kyrs inferring minimal anthropogenic impacts on foraminiferal calcification. Interspecies-specific responses are evident, as the test weight of G. bulloides increases since the early 1900s in response to a warming North Altantic Current, whilst Neogloboquadrina incompta shows little change over the last 200 years. Furthermore, an increase in the degree of calcification of the abundant coccolithophore Emiliania huxleyi occurs in response to accelerated 20th century climate change pointing towards increased carbonate burial in the sub-polar North Atlantic under future global change.
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Squire, Gareth. "The biogeography of the Indo-West Pacific echinoids." Thesis, Queen Mary, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391824.
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Knotz, Susanna [Verfasser]. "Trophic interactions in the pelagic / Susanna Knotz." Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019744219/34.
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Walters, Louise. "Lipid oxidation in salt-dried pelagic fish." Thesis, University of Lincoln, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262195.
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Scoulding, Ben. "In situ target strength of pelagic fish." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230706.
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Moura, Salvador Tavares de. "Serra Pelada: experiência, memórias e disputas." Pontifícia Universidade Católica de São Paulo, 2008. https://tede2.pucsp.br/handle/handle/13071.
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This paper is proposed to discuss the relations of work and the living conditions of workers in the gold mining camps of Serra Pelada, in southeastern Pará, from the memory of the mining's workers. Thus, from the experiences, we can understand the workers in their relationship with the authorities and with the different workers. This reflection allows questioning the past and confronts the different memories of the mining's workers with each other, and with the authoritarian practices of the military regime in the administration of gold mining camps in the years 1980. In this process, the struggle for land indicates how the memory is an argument and builds the place in the formation of consciousness of the miners through the experience. This perspective indicates an intentional choice to deal directly with sectors that had few opportunities to exhibit their point of view. Thus, the role of narrators and the relationship between them and the researcher becomes the object of reflection, and the evidence shows the complexity of the place where the narratives are legitimate and earn meanings. The intention is the visibility to the struggle of the miners of Sierra Pelada from the plurality of memories, their living conditions and housing of today. The present, thus, turns into the right to the memory, the question of how public politics in relation to miners mix itself in the dispute by hegemony, muting projects and alternative possibilities of building other different histories of which were submitted. It discusses the construction of the images on the gold mining camps and the construction of the Carajás region from different perspectives and interests. Furthermore, a revision in the literature on the subject of gold mining camps in the region. Are addressed the questions about the construction of the work, realizing the formation of the gold mining camps as territory, experience shared by the various citizens involved. Serra Pelada emerges as place where disputes between miners, entrepreneurs, CVRD and military, were marked by tensions and struggles. The experience of the gold mining camps changed the miners, forging in the territory, the emergence and the formation of new social citizens
O presente trabalho propõe-se a discutir as relações de trabalho e as condições de vida dos trabalhadores do garimpo de Serra Pelada no sudeste do Pará a partir de diversas memórias, alimentada pela imprensa, pesquisadores e garimpeiros. Partindo das vivências dos trabalhadores, podemos compreender sua relação com o poder instituído e com os diferentes garimpeiros. Essa reflexão possibilita questionar o passado e confrontar as diferentes memórias dos garimpeiros entre si e com as práticas autoritárias do regime militar para a administração do garimpo no inicio da década de 1980. Nesse processo, a luta pela terra indica como a memória constitui-se em argumento e constrói o lugar na formação da consciência dos garimpeiros através da experiência. Essa perspectiva indica uma escolha intencional ao tratar diretamente com setores que tiveram poucas oportunidades para expor suas visões. Desta forma, o papel dos narradores e a relação estabelecida entre eles e o pesquisador passa a ser objeto de reflexão, e nos sugere indícios da complexidade do lugar onde as narrativas se legitimam e ganham significados. Busca-se dar visibilidade a luta dos garimpeiros de Serra Pelada a partir da pluralidade das memórias, de suas condições de vida e moradia atuais. O presente, assim, converte-se no direito a memória, ao questionar como as políticas públicas em relação ao garimpeiro se engendram na disputa por hegemonias, silenciando projetos alternativos e possibilidades de construção de outras historicidades distintas das quais foram submetidas. Discute-se a construção das imagens sobre o garimpo e a constituição da região do Carajás a partir de diferentes perspectivas e interesses. Propõe-se, ainda, uma revisão na bibliografia sobre a temática do garimpo e da região. São abordadas as questões da construção do trabalho, percebendo a formação do garimpo como território, experiência compartilhada pelos diversos sujeitos envolvidos. Serra Pelada surge como lugar onde se desenrolam as disputas entre garimpeiros, empresários, CVRD (Companhia Vale do Rio Doce) e militares, marcadas por tensões e lutas. A experiência do garimpo transformou o garimpeiro, forjando no território o surgimento e constituição desses novos sujeitos sociais
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RAVILLY, GUILLAUME. "Adhesion et pelage bidimensionnel des polymeres." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10024.
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L'etude vise a approfondir le test de pelage a 90\. Le comportement en pelage d'un adhesif est un phenomene complexe lie a la geometrie du systeme. La force necessaire pour separer l'adhesif du substrat depend a la fois des proprietes rheologiques de l'adhesif et des proprietes de surface qui vont engendrer une geometrie particuliere de la bande adhesive, notamment au niveau du rayon de courbure. Plusieurs parametres peuvent influencer les proprietes de pelage : la rigidite de la bande adhesive, l'epaisseur d'adhesif, les energies de surface, la vitesse de pelage. Ce travail debute par l'etude du pelage en regime cohesif aux tres basses vitesses. Nous validons un nouveau modele theorique capable de determiner l'energie de pelage en fonction des parametres cites plus haut. Ce modele etabli a partir de parametres adimensionnels, est compare aux resultats experimentaux obtenus avec differents supports et adhesifs (pdms) dans une large gamme de vitesses. Nous verifions aussi qu'un critere de transition simple permet de passer du regime cohesif bidimensionnel au regime cohesif tridimensionnel. La seconde partie de ce travail concerne la rupture adhesive. Apres avoir caracterise les surfaces des substrats et des supports utilises, tant d'un point de vue geometrique (rugosite) que physico-chimique (mouillage), nous realisons des experiences de pelage en regime adhesif en utilisant un pdms de grande masse moleculaire. Nous etudions l'influence des parametres deja evoques ci-dessus. Ensuite nous effectuons des visualisations de surfaces pelees en regime adhesif sous meb qui demontrent que le pelage adhesif laisse en realite une fine couche de pdms sur le substrat. Enfin, nous montrons qu'un modele theorique base sur les proprietes elongationnelles de l'adhesif et la loi de lodge peut difficilement etre cale sur les resultats experimentaux du pelage adhesif bidimensionnel. Par contre, nous validons un nouveau modele theorique simple qui represente tres bien nos resultats.
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Haupt, Florian. "Plankton vertical migrations - Implications for the pelagic ecosystem." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-135130.
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Dahl, Maria, and Emma Hansson. "Montagestagning utav pelar- balksystem." Thesis, Växjö University, School of Technology and Design, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-5214.
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Rapporten är sammanställda studier av hur prefabricerade betongstommar av pelare och balkar montagestagas idag. Stommarna används främst till industri, offentliga samt kommersiella byggnader. Fokus är lagt på de två vanligaste balktyperna raka balkar med I-tvärsnitt samt sadelformade balkar med I-tvärsnitt.
Vid montering av pelare- balksystem uppstår lastfall som man inte vill dimensionera elementen för. Stagning av konstruktionerna sker därför med hjälp av kolvning som kompletteras med wirekryss vid behov.
Resultatet har sammanställts i en enhetlig standard gällande utformning och dimensionering av montagestagning för prefabricerade betongstommar av pelare och balkar.
Nyckelord: Montagestagning, Prefabricerade system, Raka och sadelformade balkar, kolvning, wirekryss
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Regan, Gemma. "The evolution of pelage colouration in primates." Thesis, Online version, 1998. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.286468.
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Abeille, Régis. "Algorithmes d’extraction robuste de l’intervalle-inter pulse du biosonar du cachalot : applications éthologiques et suivi des populations." Thesis, Toulon, 2013. http://www.theses.fr/2013TOUL0016/document.
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Le cachalot, Physeter macrocephalus le plus grand des odontocètes, a été longtemps exposé à la pêche pour extraire l'huile contenue dans sa tête (spermaceti), et est maintenant vulnérable. Les cachalots nagent dans divers endroits du globe et atteignent les plus grandes profondeurs, où ils chassent par écholocation. Ils émettent des sons, des clics à large bande, à structure multi-pulsée générée par des réflexions intra-tête. Ces clics contiennent de l'information sur la taille de l'animal et sur son orientation, reposant sur les délais entre les pulses qui le composent (intervalle inter-pulse 'IPI'). Ces mesures sont utiles dans la préservation et les efforts de suivi populationnel du cachalot, puisqu'il est impossible de filmer ces mammifères nageant en grandes profondeurs.Les avancées technologiques permettant un essor considérable du nombre d'enregistrements sous-marins. Des algorithmes d'analyse automatiques sont alors requis pour le suivi de cette population ou des études comportementales et mesures de protection. La littérature offre une variété de méthodes pour le calcul de l'IPI. Cependant, elles souffrent d'un mélange des différents délais entre pulses résultant en une estimation de l'IPI peu précise et, par conséquent, de la taille de l'animal. De plus, ce mélange des différents délais entre pulses ne permet pas l'extraction de données sur l'orientation de l'animal. Dans cette thèse, une nouvelle méthode pour une analyse fine de l'IPI est présentée. Elle ne mélange pas les différents délais entre pulses, mais sélectionne les pulses à travers une analyse combinatoire et statistique. Il en résulte une meilleure estimation de la taille du cachalot. De plus une information supplémentaire, sur son orientation, est extraite. Notre algorithme est comparé avec ceux de l'état de l'art. Nous en discutons ses forces et faiblesses.Les résultats expérimentaux sont donnés autant sur des exemples avec un ou plusieurs cachalots émettant en même temps, que sur des données obtenues en différentes zones géographiques (France, Italie, Etats-Unis) et à partir de différents systèmes d'enregistrement. Ceci démontre la robustesse de la méthode proposée, et donne des perspectives pour le suivi des cachalots à l'échelle du globeThe sperm whale, Physeter macrocephalus, the largest odontocete has been exposed for years to whaling due to the presence of liquid wax located in its head (spermaceti). This species is now considered as vulnerable. Sperm whales are located in various oceans and seas around the world. These animals are able to reach the deepest depths, where they use an echolocation technique to hunt. They emit broadband clicks that are comprised of a multi-pulse structure resulting from intra-head reflexions(spermaceti). These clicks contain information about the length of the animal and on its orientation, which reside in the delays between the pulse structure within the clicks, known as the Inter-Pulse-Interval (IPI). Measurement of these IPIs are determinant in the in the global preservation and the monitoring of sperwhales population since it is highly difficult to obtain visual clues of these deep-diving mammals.Moreover, the increasing technological advances have enabled the obtention of larger amount of underwater recordings. Therefore, the use of computational methodologies to automatically analyze the sperm whales click sounds have become a necessity in order to carry out populations monitoring and marine ecosystems studies. The current literature offers a variety of methodologies to calculate the IPI. However, these methodologies suffer from a merging of the different pulse delays and thus leading to less accurate estimation of the IPI and, in turn, of the whale's size. Moreover, from this merging methods no additional information regarding the orientation of the sperm whale can be easily extracted. In this thesis work, a new methodology for accurate IPI estimation is presented without relying on the merging of the different pulse delays, but, instead, by selecting the unique candidate pulse through a combinatorial and statistical analysis resulting in a better precision in the final estimation of the sperm whale's size and providing additional information on the whale's orientation.Our methodologies are compared with the known state of the art algorithms and their strengths and weaknesses are discussed. Experimental results are showcased of single and multi-whale examples from a variety of data obtained in different locations such as France, Italy and Canada and diverse acquiring systems. This strategy permits to testify and evaluate the robustness of the proposed methods and give perspectives in sperm whale monitoring at a global scale
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Salazar, Guiral Guillem. "Large-scale biogeography of marine pelagic bacteria and archaea." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/665818.
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The dark ocean contains about 70% of the ocean’s microbial cells and 60% of its heterotrophic activity, which is mainly fueled by the flux of organic particles produced in the surface ocean and exported to the bathypelagic ocean (1,000 – 4,000 m depth). The bathypelagic ocean represents a nonhomogeneous environment and contains a variety of particles that are considered as the main supply of organic carbon to this environment. The microorganisms inhabiting this realm play a pivotal regulatory role in the biogeochemical cycles at a planetary scale. Accordingly, the study of these microorganisms is an essential step to decipher the ecological functioning of the deep ocean.
Chapters 1 to 3 in this Thesis are dedicated to the description of the prokaryotic community composition in the bathypelagic ocean at a global scale through the sequencing of ribosomal DNA and RNA fragments using data collected during the Malaspina 2010 expedition. Chapter 1 identifies the dominant prokaryotes in the deep ocean and reveals a high proportion (~50%) of previously undescribed prokaryotes. The water masses and the structure of the deep ocean’s floor, organized into basins, are identified as the main drivers of their biogeography. Chapter 2 addresses the differences between free-living and particle-attached bathypelagic prokaryotic communities. This is shown to be a phylogenetically conserved trait, indicating that the bathypelagic particles and the water surrounding them constitute two distinct niches and that transitions from one to the other have been rare at an evolutionary timescale. Finally, in Chapter 3 we identify a linear relationship between the 16S RNA/DNA ratio and particle attachment preference, suggesting a global relationship between the prokaryote’s preference for a particle-attached lifestyle and their growth rate.
While the deep ocean is a highly unexplored environment, a more complete knowledge exists for the epipelagic ocean (0 – 200 m depth). Steep gradients of light intensity and quality, temperature and nutrient availability characterize the oceans and impact on the distribution of species. However, different processes, such as the sinking of particles and the vertical movement of water masses, have been described as mechanisms capable of connecting the surface and deep layers of the ocean. These same processes could transport entire prokaryotic communities, a process theoretically proposed but never tested. In Chapter 4 we develop a tool (mtagger) for the extraction of short 16S ribosomal reads from metagenomes to describe the taxonomical composition of microbial communities. We propose and evaluate technical improvements compared to previous versions as a benchmark for its use in the last chapter. Chapter 5 is dedicated to the development of a modeling tool (disperflux) for the analysis of prokaryotic communities’ connectivity using data collected during the Tara Oceans expedition. We observe and describe a fast-decay relationship between community similarity and depth, which is consistently fitted by a power-law across the whole dataset, with the exception of 5 stations that are compatible with events of whole community export from the photic ocean to the mesopelagic.
In summary, this Thesis significantly contributes to the knowledge on the ecological functioning of marine prokaryotes by describing the structure of prokaryotic communities along the bathypelagic realm and the vertical gradient of the ocean and by the development of original methodological tools that may be applied to a variety of environments.El océano profundo contiene el 70% de las células microbianas del océano las cuales suponen el 60% de la actividad heterotrófica. Dicha actividad biológica está mantenida por un flujo de partículas orgánicas producidas en el océano superficial y exportadas al océano batipelágico (1,000 - 4,000 m de profundidad). Éste no es, por tanto, un ambiente homogéneo, sino que contiene una variedad de partículas consideradas el aporte dominante de carbono orgánico. Los microorganismos de este ambiente tienen, por tanto, un papel regulatorio central en los ciclos biogeoquímicos planetarios. Consecuentemente, el estudio de estos microorganismos supone un paso esencial para descifrar el funcionamiento ecológico del océano profundo. Los Capítulos 1 a 3 de esta Tesis están dedicados a la descripción a nivel global de la composición de las comunidades de procariotas en el océano batipelágico mediante la secuenciación de fragmentos del ADN y ARN ribosomal. En el Capítulo 1 se identifican los procariotas dominantes en el océano profundo y se revela la existencia de una alta proporción (~50%) de procariotas previamente no descritos. Se reconocen además las masas de agua y la orografía del fondo oceánico, organizado en cuencas, como factores claves en su biogeografía. En el Capítulo 2 se estudian las diferencias entre las comunidades de procariotas de vida libre y aquellos adheridos a partículas. Este rasgo se demuestra estar conservado filogenéticamente, indicando que las partículas del batipelágico y el agua que las rodea constituyen dos nichos claramente diferenciados y que las transiciones entre uno y otro por parte de los procariotas han sido eventos poco frecuentes a escalas evolutivas. Finalmente se identifica en el Capítulo 3 una relación lineal entre el cociente de 16S ARN/ADN ribosomal y la preferencia a un modo de vida adherido a partículas, lo que sugiere una relación a nivel global entre la adherencia a partículas y su tasa de crecimiento. Mientras el océano profundo es un ambiente ampliamente inexplorado, existe un mayor conocimiento del océano superficial o epipelágico (0 - 200 m de profundidad). Gradientes intensos en la cantidad y calidad de la luz, temperatura y concentración de nutrientes caracterizan a los océanos e influyen en la distribución vertical de las especies. Sin embargo, diferentes procesos, tales como la deposición de partículas o los movimientos verticales de masas de agua, se han descrito como mecanismos capaces de conectar las capas superficiales y profundas del océano. Estos mismos procesos podrían teóricamente exportar comunidades enteras de microorganismos, un proceso teóricamente propuesto pero no evaluado hasta la fecha. En el Capítulo 4 se desarrolla una herramienta informática (mtagger) para la utilización de fragmentos del gen 16S ribosomal extraídos de metagenomas y su utilización para la descripción taxonómica de comunidades de procariotas. En este capítulo se proponen y evalúan mejoras respecto a versiones anteriormente utilizadas, como paso previo a su uso en el último capítulo. El Capítulo 5 está dedicado al desarrollo de un modelo matemático (disperflux) para la descripción de la conectividad vertical entre comunidades de procariotas. Se observa y describe una disminución abrupta de la similitud de las comunidades de procariotas con la profundidad. Esta relación se ajusta a una ecuación potencial que resulta consistente a lo largo de todo el océano, a excepción de 5 localizaciones, que se demuestran compatibles con eventos de exportación masiva de comunidades desde la superficie al océano profundo. En resumen, esta tesis ha contribuido significativamente al conocimiento del funcionamiento ecológico de los procariotas marinos mediante la descripción a nivel global de estas comunidades en el océano profundo y en el gradiente vertical así como mediante el desarrollo de herramientas metodológicas novedosas aplicables a una amplia variedad de entornos
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Sapp, Melanie. "Interactions of marine bacteria in the pelagic food web." [S.l.] : [s.n.], 2006. http://e-diss.uni-kiel.de/diss_1783/d1783.pdf.
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Mannini, Piero. "Ecology of the pelagic fish resources of Lake Tanganyika." Thesis, University of Hull, 1998. http://hydra.hull.ac.uk/resources/hull:5722.
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Most of the scientific knowledge on the pelagic fish (the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) of Lake Tanganyika is from research carried out in localised areas. This makes it difficult to extend the results to the whole lake. Consequently, there is the need to study the pelagic fish resources on a lake-wide basis using the same data collection procedures. Within the framework of an international fishery research project, data from the commercial fisheries targeting the pelagic fish stocks were simultaneously collected at various sampling sites in the riparian countries. Fishery-independent data were also obtained from lake-wide research surveys. The life histories of the three fish species appear to be similar throughout the lake. However, fish distribution across the lake is very uneven. The clupeid S. tanganicae mostly occur in the northern half of the lake and is much reduced in southern areas. This appears to be a recent contraction of the distribution range of this species. Limnothrissa miodon is more evenly distributed than S. tanganicae. The two species have a different inshore-offshore, size-related distribution across the lake. Nursery grounds of the first are close to the shore while those of S. tanganicae are in open, pelagic waters. With increase in size, S. tanganicae tend to move inshore while large L. miodon display the opposite movement. Lates stappersii stock, although relatively common, tends to be at higher concentration in the deep, steep central and southern basins. The feeding ecology of L. stappersii varies depending on the area and prey availability, but is mainly based on S. tanganicae and pelagic shrimps. Local occurrence of S. tanganicae is associated with that of copepod prey. The fish stocks experience different exploitation rates across the lake. While the fishing pressure is not excessive in the most of the lake areas, in others local overfishing is taking place. The biological characteristics of the pelagic fish species are discussed for the management of the lake fisheries. Fisheries management options are formulated on the basis of the assessment of the current exploitation levels.
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Pinnegar, John Keith. "Planktivorous fishes : links between the Mediterranean littoral and pelagic." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311108.
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da, Silva Queiroz Fabiane. "Síntese de texturas: coloração contrastante de pelagem de mamíferos." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/2748.
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Previous issue date: 2011Conselho Nacional de Desenvolvimento Científico e Tecnológico
Integrar harmoniosamente a forma e a aparência de objetos sintetizados ainda é um dos maiores desafios da Computação Gráfica. Para alguns objetos específicos, como animais com padrões na pelagem, informações de forma e aparência estão intimamente ligadas por uma relação de dependência, logo, o tratamento separado destes dois aspectos dificulta o processo como um todo e limita os resultados visuais. Uma abordagem para resolver esse problema efetua o processamento de ambas as etapas - criação da forma e aparência - em conjunto, gerando assim texturas denominadas inteligentes, visto que estas devem se adaptar à superfície do objeto de acordo com os critérios geométricos do mesmo. O Modelo Mosaico de Clones - MClone - apresentou uma abordagem para a síntese inteligente de texturas que representam padrões de pelagem em alguns mamíferos tais como os grandes felinos e a girafa. Esta dissertação estende o modelo MClone para a simulação biologicamente plausível de padrões de pelagem contrastantes, em sua maioria que se manifestam nas cores branco e preto, sendo este padrão distribuído de forma aleatória - como se vê facilmente em algumas espécies de cavalos, vacas, gatos, dentre outros - ou estruturada, como o padrão listrado de zebras. As principais contribuições são a adição de um modelo de crista neural e de campos vetoriais definidos na superfície do objeto para controle das simulações. Os resultados visuais obtidos para vários mamíferos com padrões contrastantes como vacas, cavalos, e zebras, confirmam as vantagens de uma abordagem integradora como a do modelo MClone para geração procedural de texturas de uma ampla coleção de objetos do Reino Animal
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Bochenek, Eleanor A. "Virginia's pelagic recreational fishery: Biological, socioeconomic and fishery components." W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539616572.
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Catch, effort, fleet size and boat owner expenditure data were collected on Virginia's recreational marlin/tuna fishery for the 1983-1985 seasons. Logbooks, dockside interviews and a telephone survey were evaluated to determine which method was the most efficient and effective for collecting and estimating catch and effort for Virginia's pelagic recreational fishery. In 1984, logbooks were used to collect catch and effort data and fishing effort was estimated using Bochenek's method. Very few fishermen returned their logbooks and as a result this data is probably less reliable than the data collected in other years. Due to the poor return of logbooks, this method should not be used to assess Virginia's marlin/tuna fishery. For the 1985 season, Figley's telephone survey (1984) was compared to the NMFS dockside interview technique for large pelagics. Both the telephone survey using Figley's technique (1984) and dockside interviews using Bochenek's method for calculating effort appear to provide similar estimates of projected total catch. However, the dockside method is very labor intensive, costly and fraught with problems in estimating fishing effort. Therefore, the telephone survey technique using Figley's method for estimating effort appears to be a better method for analyzing this fishery. If telephone interviewing will not work in an area and dockside sampling methods must be relied upon to study the pelagic fishery, Bochenek's method appears to produce a better estimate of fishing effort. Using Figley's (1984) mark-recapture technique, Virginia's pelagic recreational fleet was estimated at 455 and 774 vessels in 1983 and 1985, respectively. Boat owner expenditures for this fleet were estimated at &3,863,045 in 1983, \&4,057,020 in 1984 and &5,538,191 in 1985. Bluefin tuna were caught at SST ranging from 58-83 F but seem to prefer SST of 70 to 75 F. Yellowfin tuna were caught at SST ranging from 68-86 F with the majority landed at SST of 76-80 F. White marlin appear to prefer SST of 74 to 81 F.
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Gear, Robert William. "The development of Shetland's pelagic fishing industry, 1945-2000." Thesis, University of Hull, 2012. http://hydra.hull.ac.uk/resources/hull:13571.
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This thesis is a case study in the transformation of a fishing industry on the North Atlantic fringe between 1945 and 2000. Fishing industries worldwide underwent fundamental and wide-ranging changes during this post-war period. For the fishing industries of the North Atlantic, the 1970s were a time of particularly profound crisis and change. Three interlinked revolutions were at their height: the second industrialisation of fisheries, the territorialisation of the seas and the imposition of multifarious fisheries management measures. These combined to mean that access to marine resources were seriously curtailed. Many fishing industries on the North Atlantic rim suffered and some never recovered. In contrast the Shetland pelagic fishing industry emerged from the crisis period having experienced a particularly dramatic and positive transformation. Part 1 (chapters 2 and 3) detail these changes in the catching and processing sectors. Part 2 analyses the forces which drove this development. It is demonstrated that these changes in the pelagic industry in Shetland were driven by three primary factors. In chapter 4, environmental and sociological drivers are examined together under a holistic framework known as the ‘maritime cultural landscape.’ It is shown that Shetland’s environmental context - as an isolated relatively barren island in the North Atlantic surrounded by fecund seas - has made the exploitation of marine resources both practical and necessary. Further, it describes how the historic socio-culture of the archipelago has been shaped by fishing, and in the post-war period how this was especially manifest in some of the outlying islands. Chapter 5 analyses the impact that market forces (demand) and technological drivers (supply) had on the development of the industry. It shows that consistent demand from Continental Europe has been the industry’s backbone but that increasing globalisation opened up new markets to the local processors. The chapter also argues that new catching methods increased productivity and profit and impelled development in other spheres such as vessel design and processing techniques. Finally chapter 6 discusses the political factors which have underpinned the industry’s development and argues that various forms of subvention and management measures impacted the industry’s development in a particularly positive way. Part 3 puts these developments in Shetland’s pelagic sector in the context of other North Atlantic maritime communities. The peculiarities of the Shetland case are especially highlighted. In summation, the work posits that the Shetland pelagic industry developed dramatically during the 1945-2000 period due to the positive confluence of three primary drivers, and the particular interaction of these drivers can explain the peculiarities of the Shetland example.
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Gorni, Guilherme Rossi. "Interações tróficas entre espécies pelágicas do Atlântico Sudoeste : utilizando isótopos estáveis e inferência bayesiana /." Rio Claro : [s.n.], 2010. http://hdl.handle.net/11449/106607.
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Orientador: Roberto GoiteinBanca: Alberto Ferreira de Amorim
Banca: Selene Maria Coelho Loibel
Banca: Leandro Muller Gomiero
Banca: Lucy Satiko Hashimoto Soares
Resumo: Visando contribui r para o conhecimento da dieta de peixes que habitam o ambiente pelágico do Oceano Atlântico Sudoeste, e por conseqüência compreender a rede trófica na qual estas espécies estão inseridas, foi elaborado um estudo envolvendo t rês aspectos apresentados nesta tese em forma de capítulos: (1) análise do conteúdo estomacal de Thunnus albacares, T. obesus, T. alalunga, Xiphias gladius, Isurus oxyrinchus e Alopias superciliosus; (2) uso da inferência bayesiana na análise da dieta dos predadores em questão; (3) caracterização da rede t rófica pelágica considerando as assinaturas isotópicas dos consumidores e suas presas. A coleta dos peixes foi realizada em parceria com a frota atuneira de Santos - SP, cuja área de operação compreende o mar aberto frente às regiões Sudeste e Sul do Brasil . De maneira geral, os resultados indicam que: (1) A dieta de T. albacares e T. obesus é composta primariamente por peixes teleósteos (Bramidae, Gempylidae, Trichiuridae, ent re outros), e secundariamente por moluscos Teuthida (lulas em geral ); (2) Thunnus alalunga apresentou um padrão inverso aos demais atuns anal isados, alimentando-se preferencialmente de moluscos Teuthida, deixando os peixes teleósteos em segundo plano; (3) O espadarte (Xiphias gladius) alimenta-se primariamente de lulas Ommast rephidae; (4) a alimentação de I. oxyrinchus e A. superciliosus foi dominada por cefalópodes da ordem Teuthida. Ent re os peixes, destaque para as famílias Scombridae e Trichiuridae; (5) A análise da assinatura isotópica dos predadores corroborou os padrões descri tos pela análise do conteúdo estomacal; (6) as espécies de Scombridae são presas importantes para os predadores de topo, como X. gladius e A. superciliosus. Os achados remontam a importância de pesquisas que analisem a alimentação de peixes explorados comercialmente, visto que estes estudos podem... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In order to cont ribute to the diet knowledge of fish that inhabit the pelagic environment of the southwest Atlantic Ocean, and in consequence be aware about this species insertion in the t rophic web, a study involving four distinct aspects was made up in chapters: (1) stomach content analyses of Thunnus albacares, T. obesus, T. alalunga, Xiphias gladius, Isurus oxyrinchus e Alopias superciliosus; (2) use of Bayesian inference in analyzing the diet of these predators; (3) by using the isotopic signatures of the predators, as well as their prey, to assume thei r trophic role in the system. Fish collect ions were made by collaboration of the Santos-SP tuna fishery fleet, which operates in an area comprising the open sea off the southern and southeastern Brazilian coast . In general results indicate that: (1) The T. albacares and T. obesus diet consists primarily of teleost fishes (Bramidae, Gempyl idae, Trichiuridae, among others), and secondarily of Teuthida squids; (2) Thunnus alalunga showed an opposite food composition when compared to the other tunas, feeding mainly on Teuthida squids, and teleost fish comprised a second food in importance; (3) the swordfish (Xiphias gladius) feeds mainly on the Ommast rephidae squids; (4) the food of I. oxyrinchus and A. superciliosus was dominated by cephalopods Teuthida. Among fishes, the emphasis is represented by the representatives of families Scombridae and Trichiuridae; (5) (5) The predators isotopic signature analysis corroborated the described pat terns shown by the stomach contents analyses; (6) The Scombridae species are important prey species for the top predators, such as X. gladius and A. superciliosus. The findings should help one to remember the importance of investigat ions related to fish species, which use to be important for commercial purposes, as such studies may become essential tools to be used by alternative conservation... (Complete abstract click electronic access below)
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Roivainen, J. (Jarmo). "Keskustelu jalkapallon Kaikki Pelaa -järjestelmästä." Bachelor's thesis, University of Oulu, 2018. http://urn.fi/URN:NBN:fi:oulu-201806052453.
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BRYSELBOUT, ERIC. "La chirurgie des membranes epiretiniennes idiopathiques et secondaires : a propos de 50 cas." Amiens, 1990. http://www.theses.fr/1990AMIEM037.
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Granqvist, Daniel. "Klimatberäkningar för grundförstärkningsmetoden KC-pelare hos programmet Geokalkyl." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-137177.
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Vid projektering av väg- och järnväg är det viktigt att i ett tidigt skede som möjligt få en uppfattning om hur kostnaden kommer vara samt vilken klimatpåverkan arbetet kommer medföra. Det finns olika beräkningsprogram som utför både en kostnad och klimatkalkyl vid byggnation av väg- och järnväg. Exempel på beräkningsprogram är Geokalkyl och Klimatkalkyl. Tidigare har en fallstudie utförts mellan Klimatkalkyl och Geokalkyl där det visade på att vid användningen av grundförstärkningsmetoden kalkcement-pelare beräknar Geokalkyl klimatpåverkan 30 gånger så högt som klimatkalkyl. Syftet med det här projektet är att undersöka och vidareutveckla beräkningssättet för kalkcement-pelare hos programmet Geokalkyl. Grundförstärkningsmetoden kalkcement-pelare används bland annat för att stabilisera väg- och järnvägsbankar. Nedsättningen för pelarna är med hjälp av en maskin, blandningsbärare samt en tank förvarar blandningen. Vid nedsättning borrar maskinen ned till önskat djup. Då borren nått önskat djup roterar den upp samtidigt som blandning mängden släpps ut. Blandningen bildar tillsammans med jorden de fasta pelarna som stabiliserar marken. Geokalkyl gör beräkningarna i ett Excelverktyg där hänvisningar sker mellan olika blad i Excel. Ekvationen som gör beräkningen finns under fliken Indata. Alla arbetsmoment för kalkcement-pelare beräknas i samma ekvation där hänvisningar sker till separata informationsbilagor. Maskinförbrukningarna hänvisas till en dold Excelflik, Hagert. De justerbara parametrarna finns under fliken In parametrar. De parametrar som är justerbara är transportlängd och vilken klimatpåverkan pelarna har per längdmeter. Klimatpåverkan mäts i använda kWh och mängden koldioxidekvivalenter. För att uppnå syftet valdes följande utförande. Först inläsning på området, därefter tolkning av tidigare beräkningssätt och till sist uppbyggnad av nya beräkningssättet. Avgränsningarna för projektet är att endast se över specifika arbetsmoment som tillkommer vid användning av grundförstärkningsmetoden kalkcement-pelare hos Geokalkyl. Tidigare beräkningssättet hade bristfälliga hänvisningar till informationsbilagorna, samt felaktiga och bortglömda arbetsmoment. De beräkningarna som var felaktiga var dels att beräkningen tog hänsyn till en dimension men enligt informationsbilagorna skall den variera. Det var även en felaktig volym i pelarna, detta sågs genom att framställningsvärden per längdmeter pelare var med felaktig beräkning på dimension. Exempel på arbeten som tidigare beräkning ej tog hänsyn till var arbetet kring nedsättning, det vill säga förbrukning för maskinen och bäraren samt dess maskintransporter. För att bygga upp det nya beräkningssättet identifierades samtliga arbetsmoment kring kalkcement-metoden. Där respektive arbetsmoment fick en separat ekvation. Samtidigt så lyftes beräkningarna från Hagert till samma Excelblad som resterande beräkning. Alla antaganden från informationsbilagorna lyftes även in till Excelbladet. Genom att alla antaganden och beräkningar nu sker på samma Excelblad gör det beräkningen väldigt följsam. Förutom att beräkningen är följsam så är den lätt att justera genom att alla antaganden syns och att samtliga arbetsmoment har en separat ekvation. De arbeten som är utöver detta arbete måste ses över för att beräkningssättet skall kunna ersätta det befintliga i Geokalkyl.
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Neto, Militao Teresa Afonso. "Understanding migration of pelagic seabirds with stable isotopes and geolocation." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/398988.
Full textAbstract:
Animal migration is an amazing widespread phenomenon that forms an essential component of the animal life history. Animals usually migrate to take advantages of changes in resource availability in space and time or to find suitable habitats for different life-history stages, which ultimately may improve their fitness. Unfortunately, migratory species are currently experiencing substantial population declines because of the several threats they are exposed to. These largely depend on their migratory patterns, and therefore its study is crucial for the effective conservation of migratory species. Despite our wealth of knowledge on avian migration, the study of migratory ecology of pelagic seabirds is still very challenging, especially in small species. Until recently, most studies on seabird migration focused on species of the Southern Ocean, while our knowledge on Mediterranean, tropical and subtropical Atlantic species is scarcer.
In this thesis, we aim to fill in this gap of knowledge for a number of pelagic seabirds of the Mediterranean and the Atlantic, by studying the migratory patterns of 7 shearwaters, 4 petrels and 1 gull species. More specifically, we (1) increase our knowledge on different methodologies for seabird identification as a preliminary step to study their migratory movements; (2) evaluate the utility of stable isotopes analysis (SIA) to infer the non-breeding areas of pelagic seabirds, and; (3) reveal the migratory patterns and non-breeding areas of the study species using geolocation or a combination of SIA and geolocation data.
Our findings pointed out the importance of integrating different methodologies to distinguish individuals of closely related or recently diverged species and thus overcome their identification difficulty. Furthermore, we demonstrated the utility of SIA as powerful approach to discriminate species that explore isotopically distinct areas. We verified a generally high efficiency of SIA on feathers as a geographic marker to infer the previous non-breeding area of pelagic seabirds. However, SIA efficiency varied at inter-specific level depending on the degree of isotopic differentiation among their non-breeding areas.
Based on geolocation and isotopic data, we found a huge variability in migratory patterns among species, population and individuals. At inter-population level, we described for the first time a leap-frog migration pattern in an oceanic seabird, while at intra-population level we revealed the existence of partial migration and other complex migratory patterns.
Additionally, we integrated our results and information from literature to review the main extrinsic and intrinsic drivers of migratory patterns of small and medium size seabirds and how they may differ from the ones affecting the migration of terrestrial birds. In opposite to the characteristics of terrestrial habitats, the almost lack of major barriers to migration, the low productivity of tropical waters and the biological adaptations of seabirds to the oceanic habitats seem to contribute to the long-distance migrations and huge variability in migratory patterns of small and medium sized pelagic seabirds. However, this variability is still smaller than the one observed in terrestrial species probably because of the absence of major barriers and the milder climatic seasonality of the oceans.
Overall, this thesis gives an important contribution to a wider understanding of the complex migratory ecology of pelagic seabirds.La migració animal és un fenomen generalitzat increïble que forma un component esencial de la història de la vida animal. Els animals generalment migren per aprofitar els canvas en la disponibilitat espacial i temporal dels recursos, o per trobar un hàbitat adequat per a les diferents etapes del cicle biològic, que en última instància poden millorar la seva condició física o l’èxit reproductiu. Per desgràcia, les espècies migratòries estan actualmente experimentant una disminució substancial en les seves poblacions per causa de les diverses amenaces a què estan exposats. Això depèn en gran mesura de les seves patrons migratoris,i, per tant, el seu estudi és crucial per a la conservació efectiva de les espècies migratòries. Malgrat la nostra riquesa de coneixements sobre la migració aviària, l’estudi de l’ecologia migratòria de les aus marines pelàgiques segueix essent molt difícil, sobretot en les espècies més petites. Fins fa poc, molts dels estudis migratoris de les aus marines s’han centrat en les espècies de les aigües oceàniques de l’hemisferi sud, mentre que el nostra coneixement de les espècies del Mediterrani i de l’Atlàntic tropical i subtropical és més escassa. En aquesta tesi, el nostre objectiu és omplir aquest buit de coneixement per un nombre d’aus marines pelàgiques del Mar Mediterrani i de l’Oceà Atlàntic mitjançant l’estudi dels patrons migratoris de 7 baldrigues, petrells 4 i 1 espècie de gavina. Més específicament, volem (1) utilitzar taxonomia integrada per augmentar el nostre coneixement sobre diferents metodologies per a la identificació d’aus marines, com a pas previ per estudiar els seus moviments migratoris; (2) avaluar la utilitat de l’anàlisi d’isòtops estables (SIA) per inferir les àrees de hivernada d’aus marines pelàgiques; i (3) revelar els patrons migratoris i les àrees de hivernada de les espècie d’estudi utilitzant geolocalització o una combinació de les dades de geolocalització i SIA. Els nostres resultats assenyalen la importància d’integrar diverses metodologies per distinguir individus d’espècies estretament relacionades o que fa poc que van divergir i així superar la dificultat de la seva identificació. D’altra banda, hem demostrat la utilitat del SIA com una metodologia poderosa per discriminar les espècies que exploren àrees isotòpicament distintes. En general, hem verificat una alta eficiència del SIA de les plomes com un marcador geogràfic per inferir les àrees de hivernada de les aus pelàgiques. No obstant això, l’eficiència de SIA va variar a nivell interespecífic en funció del grau de diferenciació isotòpica entre les seves àrees de hivernada. En base a les dades de geolocalització i dels valors isotòpiques de les espècies de estudi, hem trobat una enorme variabilitat de patrons migratoris entre espècies, poblacions i individus. A nivell inter-poblacional, es va descriure per primera vegada un patró de migració salt de granota en una au oceànica, mentre que a nivell intra-poblacional es va revelar l’existència de la migració parcial i altres patrons migratoris molt complexes. A més, hem integrat els nostres resultats i la informació de la literatura per revisar els principals factors extrínsecs i intrínsecs que influencien els patrons migratoris de aus marines petites i mitjanes i com poden diferir de les que afecten la migració de les aus terrestres. Al contrari de les característiques dels hàbitats terrestres, la quasi absència de grans barreres a la migració, la baixa productivitat de les aigües tropicals i les adaptacions biològiques de les aus marines als hàbitats oceànics sembla contribuir a les seves migracions de llarga distància i gran variabilitat en els seus patrons migratoris. No obstant això, aquesta variabilitat és encara menor que l’observada en les espècies terrestres, probablement a causa de l’absència de barreres importants i de l’estacionalitat climàtica més lleu dels oceans. En general, aquesta tesi dóna una important contribució a una millor comprensió de l’ecologia complexa migratòria de les aus marines pelàgiques.
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Andersson, Eva. "Benthic-Pelagic Microbial Interactions and Carbon Cycling in Clearwater Lakes." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5798.
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Stromberg, K. H. Patrik. "Plankton size distributions and metabolism of the pelagic global ocean." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520657.
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Keech, Dominic. "The anti-pelagian Christology of Augustine of Hippo, 396-430." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527334.
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Cullins, Tammy L. "Antifreeze proteins in pelagic fishes from Marquerite Bay (western Antarctica)." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002553.
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Lewis, Nicola Dawn. "Modelling the infochemical role of dimethylsulphide in pelagic multitrophic interactions." Thesis, University of Essex, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654526.
Full textAbstract:
Dimethylsulphide (DMS) is a climate-relevant trace gas derived from the algal secondary metabolite dimethylsulphoniopropionate (DMSP). DMS and DMSP have been shown to act as infochemicals (information-conveying chemicals) for a variety of organisms over a wide range of spatial and temporal scales. Grazing by microzooplankton increases the production of DMS, which in turn may act as an infochemical cue to attract carnivorous copepods that preferentially prey on herbivorous microzooplankton. This extra copepod predation on microzooplankton could release excessive grazing pressure on phytoplankton. Such infochemical-mediated multitrophic interactions are poorly understood in pelagic systems, but may be important for the structuring and functioning of marine food webs. Experimenting with several trophic levels of plankton in laboratory microcosms is challenging and, as a result, empirical data confirming the roles of DMS and DMSP in trophic interactions is lacking. Mathematical models provide a suitable tool to gain insight into such complex interactions. The mathematical models analysed in this thesis show DMS-mediated interactions to have a stabilising effect on food web dynamics and to promote the formation of phytoplankton blooms. Food web models with two species of phytoplankton constituting the first trophic level were analysed. The key result of this analysis was that chemoattractants, which increase the susceptibility of the producer to grazing, enhance the persistence of the producing phytoplankton species by attracting carnivorous copepods to consume microzooplankton grazers. Analysis of a Nutrient-Phytoplankton-Microzooplankton-Zooplankton (NPMZ) model showed the ability of phytoplankton to bloom to be a combination of both top-down (DMS-mediated predation) and bottom-up (nutrient limitation) processes. Analysis of a model simulating these interactions in a vertically heterogeneous environment showed foraging through chemodetection to provide fitness benefits to copepods and to enhance copepod persistence. Overall the results presented indicate that infochemicals have important consequences for the dynamics of marine food webs
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Herrington, Twyla. "Socioeconomic Characteristics of Coastal Pelagic Fishing Tournaments in South Florida." NSUWorks, 2011. http://nsuworks.nova.edu/occ_stuetd/203.
Full textAbstract:
Highly migratory species (HMS) are targeted in numerous recreational fishing tournaments in the Florida Straits and very important to the total directed fisheries for these species. Sailfish Istiophorus platypterus and wahoo Acanthocybium solandri are primary coastal pelagic fish species, found in similar shelf-edge habitats, targeted in these recreational tournaments. The economic importance of these tournaments is unknown, as is the probable overlap between tournament fisheries by anglers targeting this species.
A voluntary mail survey was administered to two sailfish tournaments and one wahoo tournament within the Florida Straits during the 2009/2010 season. Questions were organized into four sections: general fishing activity and experience, tournament experience, fishing techniques, and personal angler characteristics. Response rates for the participating tournament were as follows: Stuart Sailfish Club Light Tackle Sailfish Tournament (SSCLT), 23.3%, Silver Sailfish Derby (SSD) 44.2%, and Bahamas Wahoo Championship (BWC) 33.0%. All participating tournaments represented an overwhelmingly male population (SSCLT 92.9%; SSD 94.7%, BWC 100%), the majority of which were residents of Florida. Sailfish was listed as the preferred target species for the participating sailfish tournament anglers with wahoo being listed as the preferred target species for wahoo tournament participants. All anglers in both sailfish tournaments responded yes to participation in the upcoming year’s tournament with only 50% of wahoo participants answering yes to this question for next year’s participation.
Average tournament expenditures and economic contributions were part of the results from this study. All tournaments showed highest expenditures under gas and oil for boats. The SSCLT tournaments average for oil and gas totaled $2,785.00 for the tournament, the highest of the three tournaments surveyed. Lodging was shown to be the least important of all categories with averages ranging between $325-$700 per tournament. The direct economic contribution from each tournament as whole to the local economy were as follows: SSD- $425,109; SSCLT- $866,189; Wahoo-$71,550. These numbers correspond to the total tournament participation numbers with the highest contribution and participation being the SSCLT tournament. Understanding angler preferences and expenditure patterns will help tournament directors and local fisheries management agencies better understand the economic importance and management implications in South Florida.
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De, Bodt Caroline. "Pelagic calcification and fate of carbonate production in marine systems." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210156.
Full textAbstract:
Human activities have contributed to the increase in atmospheric greenhouse gases such as carbon dioxide (CO2). This anthropogenic gas emission has led to a rise in the average Earth temperature. Moreover, the ocean constitutes the major sink for anthropogenic CO2 and its dissolution in surface waters has already resulted in an increase of seawater acidity since the beginning of the industrial revolution. This is commonly called ocean acidification. The increase in water temperature could induce modifications of the physical and chemical characteristics of the ocean. Also, the structure and the functioning of marine ecosystems may be altered as a result of ocean acidification. Phytoplankton productivity is one of the primary controls in regulating our climate, for instance via impact on atmospheric CO2 levels. Coccolithophores, of which Emiliania huxleyi is the most abundant species, are considered to be the most important pelagic calcifying organisms on Earth. Coccolithophores are characterized by calcium carbonate platelets (coccoliths) covering the exterior of the cells. They form massive blooms in temperate and sub-polar oceans and in particular along continental margin and in shelf seas. The intrinsic coupling of organic matter production and calcification in coccolithophores underlines their biogeochemical importance in the marine carbon cycle. Both processes are susceptible to change with ocean acidification and warming. Coccolithophores are further known to produce transparent exopolymer particles (TEP) that promote particle aggregation and related processes such as marine snow formation and sinking. Thus, the impact of ocean warming and acidification on coccolithophores needs to be studied and this can be carried out through a transdisciplinary approach.
The first part of this thesis consisted of laboratory experiments on E. huxleyi under controlled conditions. The aim was to estimate the effect of increasing water temperature and acidity on E. huxleyi and especially on the calcification. Cultures were conducted at different partial pressures of CO2 (pCO2); the values considered were 180, 380 and 750 ppm corresponding to past, present and future (year 2100) atmospheric pCO2. These experiments were conducted at 13°C and 18°C. The cellular calcite concentration decreases with increasing pCO2. In addition, it decreases by 34 % at 380 ppm and by 7 % at 750 ppm with an increase in temperature of 5°C. Changes in calcite production at future pCO2 values are reflected in deteriorated coccolith morphology, while temperature does not affect coccolith morphology. Our findings suggest that the sole future increase of pCO2 may have a larger negative impact on calcification than its interacting effect with temperature or the increase in temperature alone. The evolution of culture experiments allows a better comprehension of the development of a bloom in natural environments. Indeed, in order to predict the future evolution of calcifying organisms, it is required to better understand the present-day biogeochemistry and ecology of pelagic calcifying communities under field conditions.
The second part of this dissertation was dedicated to results obtained during field investigations in the northern Bay of Biscay, where frequent and recurrent coccolithophorid blooms were observed. Cruises, assisted by remote sensing, were carried out along the continental margin in 2006 (29 May – 10 June), 2007 (7 May – 24 May) and 2008 (5 May – 23 May). Relevant biogeochemical parameters were measured in the water column (temperature, salinity, dissolved oxygen, Chlorophyll-a and nutrient concentrations) in order to determine the status of the bloom at the time of the different campaigns. Calcification has been shown to be extremely important in the study area. In addition, TEP production was significant at some stations, suggesting that the northern Bay of Biscay could constitute an area of important carbon export. Mortality factors for coccolithophores were studied and the first results of lysis rates measured in this region were presented.
Results obtained during culture experiments and comparison with data reported in the literature help to better understand and to predict the future of coccolithophores in a context of climate change. Data obtained during either culture experiments or field investigations allowed a better understanding of the TEP dynamics. Finally, the high lysis rates obtained demonstrate the importance of this process in bloom decline. Nevertheless, it is clear that we only begin to understand the effects of global change on marine biogeochemistry, carbon cycling and potential feedbacks on increasing atmospheric CO2. Thus, further research with a combination of laboratory experiments, field measurements and modelling are encouraged.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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El, Rahi Joe. "Jellyfish modelling in the coastal waters of Valencia: Life cycle, transport, and stranding of Pelagia noctiluca." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
Within the framework of ODYSSEA project (grant agreement 727277), which aims at developing a platform for observing and forecasting marine data in the Mediterranean Sea, this work of thesis tackles the problem of jellyfish in the coastal waters of Spain in the Western Mediterranean basin. The first section of the work includes a short review of all native and invasive species; followed by a detailed description (sexual reproduction, behaviour and migration) of Pelagia noctiluca, the most abundant jellyfish. Afterwards, a hydrodynamic model with a resolution of 1/50 ° (ca. 2 km) and 20 vertical layers is developed with DELFT3D-FLOW for the study area; this model is coupled with a particle tracker ( DELFT 3D-PART) and a purposely developed life cycle code that combines reproduction, growth and migratory patterns of the jellyfish. The results of the model provide an unprecedented view on the life cycle P. noctiluca , the connection between spawning zones and coastal invasions and the factors that favour blooms.
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Morand, Pierre. "La meduse pelagia noctiluca en mediterranee occidentale : de la dynamique de population aux variations a long terme." Paris 7, 1989. http://www.theses.fr/1989PA077255.
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Pelagia noctiluca est une grosse meduse cosmopolite, bien adaptee a la vie oceanique grace a son cycle de vie holoplanctonique. Une compilation des observations effectuees en mediterranee nord-occidentale depuis plus d'un siecle suggere que l'espece y effectue des pullulations intermittentes, entrecoupees par de longues annees d'absence. Une periodicite plus ou moins reguliere de 12 ans caracterise cette alternance. Pour comprendre ce phenomene, on a d'abord developpe un modele deterministe de dynamique de population, construit a partir de sous-modeles decrivant la croissance, la fecondite et la mortalite des individus. En introduisant des forcages environnementaux caracteristiques de la mediterranee, on a pu simuler un cycle demographique annuel comparable a celui observe en mer lors des annees de pullulation. En soumettant cette dynamique simulee a des perturbations trophiques additionnelles, on a mise en evidence l'existence d'une saison critique, c'est-a-dire de forte sensibilite, situee de mai a juillet. Par ailleurs, sur long terme, on a etabli empiriquement l'existence d'un lien previsionnel entre certaines anomalies climatiques regionales (deficit pluviometrique notamment) et l'occurrence immediatement ulterieure d'un episode pluriannuel de pullulation
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Larsson, Niclas. "Stålkonstruktion : En jämförelse av fast inspända- och ledat infästa pelare." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-182350.
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Abstract By using steel in load-bearing structures several opportunities due to its capacity are created, therefor large spans and slender cross-sections can be used. The approach of designing loadbearing structures has been simplified over time thanks to softwares and high-capacity computers. The purpose with this report was to investigate various methods to obtain structural stability in a structural system of steel with FEM-Design. The structure in question has recently been designed using timber construction and is placed in Örnsköldsvik with the size of 330 square meters. The structural stability methods that will be investigated are structural systems with hinged- and rigid columns. Furthermore, the hinged columns are mounted with trusses for stability aspects. Normally, hall buildings receive stability thanks to diaphragm action in the profiled plate mounted to the rafters. In this case, the structural system cannot assume this stabilizing action due to thermal affects. Thus, the structural systems require alternative solutions for obtaining structural stability. In combination with the asymmetric design of the buildingdifficulties may be revealed when modelling the frameworks with steel. The result of this report includes forces and chosen cross-sections for each structural system. Moreover, attachments are presented given by the forces that stresses connecting loadbearing members. Several structural elements were required to obtain global stability of thehinged-supported structure with relatively low utilization. The rigid-supported structure required columns with larger cross-sections that will generate difficulties while mounting attachments unto the foundation. Designed columns regarding each structural system wereselected for a HEA 280 of the rigid- respectively a HEA 200 of the hinged-supported structure. In summary, establishment of a hall building of steel is more advantageous if the structural system can be designed strategically according to optimal function and not according to a predetermined appearance. However, given the conditions set in this project, a hinged-supported structure is a better alternative with respect to construction, economy, and manufacturing.Sammanfattning Användning av stål i konstruktioner öppnar nya möjligheter tack vare dess egenskaper som tillåter stora spännvidder och slanka tvärsnitt. Beräkningsgången vid dimensionering av stålkonstruktioner har över tid förenklats tack vare de datorstöd som kan användas vid kontroll av bärförmåga och stabilitet. Hallen som detta arbete baserats på har tidigare projekterats med trästomme och är beläget i Örnsköldsvik. Den 330 kvadratmeter stora, asymmetriska maskinhallen har utformats i stål med hjälp av olika metoder för stomstabilisering. I detta projekt har ledat infästa- samt fast inspända pelare jämförts som stomstabiliseringsmetod. Takkonstruktioner i hallbyggnader betraktas vanligtvis som en stabiliserande styv skiva som överför horisontalkrafter i konstruktioner. I detta projekt antogs takkonstruktionen istället vara ett kallt tak som inte uppnår skivverkan. För framtagning av dimensionerande krafter på respektive bärverk användes beräkningsprogrammet FEM-Design. Resultatet av projektet inkluderar utformning, dimensionerande krafter samt valda profiler för respektive stabiliseringsmetod. Vidare redovisas utformade infästningar efter dimensionerande krafter som beräknats vid datorberäkningarna. Av de förutsättningar som gavs i detta projekt visade det sig att flertalet stabiliserande stag respektive stora pelardimensioner krävdes för att uppnå en stabil och hållfast konstruktion som gestaltar det ursprungliga utförandet vid betraktande av de båda bärverken. En överslagsberäkning visar att det fast inspända bärverket erhöll en vikt 3,3 ton tyngre än det ledat infästa bärverket. Stora delar av viktpåslaget hade sin grund i att pelardimensioner valdes till HEA 280 som fast inspänd samt HEA 200 som ledat infäst. Slutsatsen kan sammanfattas i att användningen av stål är mer fördelaktigt när bärverket kan utformas strategiskt efter optimal funktion och inte efter ett förutbestämt, komplext utseende. Men, givet de förutsättningar som ställts i detta projekt blev följden att ett ledat infäst bärverk är ett bättre alternativ med avseende på konstruktion, tillverkning och ekonomi.
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Cai, Yan. "Bioaccumulation of mercury in pelagic fishes in NW Gulf of Mexico." Texas A&M University, 2003. http://hdl.handle.net/1969.1/3847.
Full textAbstract:
Total mercury (Hg) levels were determined in the tissues of ten taxa of pelagic
fishes, with a special emphasis on apex predators (large vertebrates). Highest Hg levels
were observed in blue marlin (Makaira nigricans), carcharhinid sharks (Genus
Carcharhinus) and little tunny (Euthynnus alletteratus), ranging from 1.08 to 10.52 ppm.
Moderate to low concentrations (<1.0 ppm) were observed in blackfin tuna (Thunnus
atlanticus), cobia (Rachycentron canadum), dolphinfish (Coryphaena hippurus), greater
amberjack (Seriola dumerili), king mackerel (Scomberomorus cavalla), wahoo
(Acanthocybium solandri) and yellowfin tuna (Thunnus albacares). For the majority of
species examined, Hg level did not vary significantly between locations (Texas and
Louisiana) and years (2002 and 2003). The relationship between Hg level and fish
size/weight was also explored and six taxa (blackfin tuna, carcharhinid sharks,
dolphinfish, king mackerel, wahoo, yellowfin tuna) showed significant positive
relationships between Hg level and body size and/or weight. Natural dietary tracers,
stable isotopes (15N, 13C) and fatty acids were used to evaluate the relationship
between Hg and trophic position and the relationship between Hg and dietary history.
Stable nitrogen isotope analysis showed that Hg levels in fish tissues were positively
associated with trophic position. Based on the 13C and 15N values of pelagic
consumers examined in this study, three natural groups were identified with cluster
analysis, and the same groupings were detected based on fatty acid profiles. This not
only confirmed the existence of these natural groupings, but also indicated that the
distinguishing factors for the grouping was likely connected with the dietary history of
these fishes. The classification tree based on the fatty acid profiles of pelagic fishes
readily separated fishes from different regions, suggesting that diets of pelagic taxa
within the same region are similar or these consumers share a common source of organic
matter in their food web. Findings from this study complement other Hg investigations
conducted in the Gulf and also furthered our understanding of the link between feeding
ecology and Hg accumulation. Moreover, the combined use of stable isotope and fatty
acid techniques provided new insights on the dietary history of pelagic fishes in the Gulf
of Mexico.
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Marti, Clelia Luisa. "Exchange processes between littoral and pelagic waters in a stratified lake." University of Western Australia. Centre for Water Research, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0005.
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[Truncated abstract] The lake boundaries are an important source of sediment, nutrients and chemicals. For life inside the lake, the exchange between the lake boundaries (littoral) and lake interior (pelagic) is of central importance to Limnology as the net flux of nutrients into the water column is both the driving force and limiting factor for most algae blooms found during the stratification period. Consequently, the understanding of the relevant processes defining such an exchange is a further step toward a sound basis for future decisions by lake managers in order to ensure high water quality. The objective of this research was to investigate the physical processes responsible for the exchange of water and particles between the lake boundaries and the lake interior. An integrated approach using field experiments and 3D modelling as applied to Lake Kinneret (Israel) is presented. The field data revealed large-scale metalimnion oscillations with amplitudes up to 10 m in response to westerly diurnal winds, the existence of a well-defined suspended particle intrusion into the metalimnion of the lake, characterized by high concentrations of organic matter, and a well-mixed benthic boundary layer (BBL). The changes in the thermal structure explained the observed vertical and horizontal movements of the suspended particle intrusion. The horizontal advective transport via the metalimnion, associated with the velocities induced by the basin-scale mode-two Poincare wave, controlled the exchange between the lake boundaries and lake interior on daily time scales. The observed BBL over the lake slope varied markedly with time and space. Detailed comparison of simulation results with field data revealed that the model captured the lake hydrodynamics for time scales from hours to days. The model could then be used to extract the residual motions in the various regions of the lake. The residual motions below the surface layer were predominantly forced by the basin-scale internal wave motions, but the residual motion in the surface layer was found to be very sensitive to the curl of the wind field. The residual circulation was responsible for redistributing mass throughout the lake basin on time scales from days to weeks. A clear connection of dynamics of the BBL with the large-scale features of the flow was addressed. The time history of the mixing in the BBL and the resulting cross-shore flux was shown to vary with the phase of the basin-scale internal waves.
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Armstrong, Nicole. "Contribution of littoral and pelagic algal photosynthesis in Boreal Plain lakes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0003/MQ59774.pdf.
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Letessier, Tom Bech. "The influence of mid-ocean ridges on euphausiid and pelagic ecology." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3229.
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1 & 2. Euphausiids comprise a major component of ecosystems in the pelagic realm, the world's largest habitat, but basin scale drivers of euphausiids diversity and abundance are poorly understood. Mid-Ocean Ridges are the largest topographical feature in the pelagic realm and their benthic and pelagic fauna have only just recently become the focus of research. This thesis present new analyses on the drivers of euphausiids species richness in the Atlantic and the Pacific, giving specific attention to the influence of Mid- Ocean Ridges. New information is given on the biogeography of euphausiids and pelagic food-web trophology of the Mid-Atlantic Ridge, and on the biogeography of pelagic decapods on the South-West Indian Ocean ridge. 3. A Generalized Additive Model framework was used to explore spatial patterns of variability in euphausiid species richness (from recognized areas of occurrence) and in numerical abundance (from the Continuous Plankton Recorder survey) in conjunction with variability in a suite of biological, physical and environmental parameters on, and at either side of, the Mid-Atlantic Ridge. Euphausiid species richness peaked in midlatitudes and was significantly higher on the ridge than in adjacent waters, but the ridge did not influence numerical abundance in the top 10 m significantly. Sea surface temperature (SST) was the most important single factor influencing both euphausiid numerical abundance (-76.7%) and species richness (34.44%). Dissolved silicate concentration, a proxy for diatom abundance, significantly increased species richness (29.46%). Increases in sea surface height variance, a proxy for mixing, increased the numerical abundance of euphausiids. GAM predictions of variability in species richness as a function of SST and depth of the mixed layer were consistent with present theories, which suggest that pelagic niche-availability is related to the thermal structure of the near surface water. 4. Using a Generalized Additive Model in the Pacific, the main drivers of species richness, in order of decreasing importance, were found to be sea surface temperature (explaining 29.53% in species variability), salinity (20.29%), longitude (-15.01%, species richness decreased from West to East), distance to coast (10.99%), and dissolved silicate concentration (9.03%). An additional linear model poorly predicted numerical abundance. The practical differences in drivers of species richness in the Atlantic and Pacific Ocean were compared. Predictions of future species richness changes in the Pacific and Atlantic were made using projected environmental change from the IPCC A1B climate scenario, suggesting an increase in species richness in temperature latitudes (30° to 60° N and S) and little to no change in low latitudes (20° N to 20° S). 5. New baseline information is presented on biogeography, abundance and vertical distribution of euphausiids along the Mid-Atlantic Ridge (40° to 62° N). 18 species were recorded, with Euphausia krohni and Thysanoessa longicaudata being most abundant. Eight species had not been recorded in the area previously. The Subpolar Front is a northern boundary to some southern species, but not a southern boundary to northern ubiquitous species that show submergence. Four major species assemblages were identified and characterised in terms of spatial distribution and species composition. Numerical abundance was highly variable but decreased by orders of magnitude with depth. The Mid-Atlantic Ridge showed only a marginal effect on euphausiid distribution and abundance patterns. 6. Zooplankton and micronektic invertebrate epi- and mesopelagic (0-200 and 200- 800m) vertical distribution (e.g. Euphausiacea, Decapoda, Amphipoda, Thecosomata, Lophogastrida) on either side of the Subpolar Front of the Mid-Atlantic Ridge is described. Dietary relationships are explored, using stable isotope ratios and fatty acid trophic marker (FATM) composition. An increase in trophic level with size was observed. Individuals from southern stations were higher in dinoflagellate Fatty Acid Trophic Markers (FATM) (22:6(n-3)) and individuals from northern stations were higher in Calanus spp and storage FATMs (20:1(n-9) and 22:1(n-9)) reflecting primary production patterns in the two survey sectors. Observations on the geographical and vertical variability in trophodynamics are discussed. 7. New baseline information is presented on the biogeography, abundance, and vertical distribution of mesopelagic (200-1000 m), crustacean micronekton on- and offseamounts of the South-West Indian Ocean Ridge (26° to 42° S). Species richness and numerical abundance were typically higher near seamounts and lower over the abyssal plains, with several species being caught uniquely on seamounts. Observations suggest that the ‘oasis effect' of seamounts conventionally associated with higher trophic levels is also applicable to pelagic micronektic crustaceans at lower trophic levels. Biophysical coupling of micronekton to seamounts may be an important factor controlling benthopelagic coupling in seamount food-webs. 8. Euphausiid and pelagic diversity is driven primarily by geographical variability in temperature, by longitudinal patterns in upwellings, and by variability in nutrient concentration. Mid-Ocean Ridges modify pelagic ecology, by raising the seafloor and by bringing in proximity true pelagic and bathypelagic predators associated with the seabed. The increase in specialized fauna and biomass associated with ridges and seamounts serves to deplete zooplankton in the near bottom layer (0-200 m) and affect systems in and above the benthic boundary layer (<200 m from the seafloor), and the benthopelagic faunal layer. Mid-Ocean Ridges may serve to structure pelagic faunal distribution, and increase the overall diversity of the world ocean. The influence of ridges in the ocean basin may be comparable to that of hedges in a farmland; whilst delimiting the extent of crops (or zooplankton assemblages), hedges serve as local hotspots of mammal and avian diversity.
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Fitzpatrick, S. F. "Global population genetic structure of the pelagic blue shark (Prionace glauca)." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557408.
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The blue shark, Prionace glauca, a large oceanic/pelagic predator with a continuous circumglobal distribution in temperate and tropical waters, is the most abundant and widespread of all extant shark species. They are heavily exploited in targeted and incidental fisheries worldwide. Concerns have been raised over the sustainability of such exploitation as severe declines in numbers have been recently observed. Sound management of any exploited fishery requires a proper understanding of the population sub structuring and basic breeding biology of the species involved. This is lacking for this ecological and economically important inhabitant of the open seas. In this study, we have developed nuclear microsatellite and mitochondrial (mtDNA) molecular markers for blue sharks. These were used in an assessment of the global population genetic structure of the species involving over 900 specimens sampled over its distribution range. Based on micro satellite data and 21 blue shark litters (N = 578 embryos), we have characterised the mating system ofthe species. Results from the analyses of microsatellite (16 loci) and mtDNA sequence (3,1 07bp) data indicate the presence of multiple stocks on a global scale (i.e. genetic substructuring). These genetic stocks were defined by major oceanic regions, thus confirming earlier physical tagging studies, which suggest that the equator acts as a barrier to dispersal between northern and southern oceans. Analysis of data comprising 32 complete mtDNA genomes, representing the distribution range species, provides new insights into the evolutionary history of blue sharks. Microsatellite DNA profiling of blue shark litters revealed a high incidence of polyandry (80.0%) in the species. Females of multiply sired litters were larger than those of single paternity litters. Furthermore, females demonstrated a tendency to have litters sired by more males as they became older and larger. Results are discussed in light of the high energetic cost associated with the aggressive nature of copulations.
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Agbesi, Eric Narh. "A bioeconomic analysis of the marine inshore pelagic fisheries of Ghana." Thesis, University of Portsmouth, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247074.
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Kobus, Milton M. "St. Augustine's view of free will prior to the Pelagian controversy." Theological Research Exchange Network (TREN), 1998. http://www.tren.com.
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Dawson, Steffany. "Juvenile Pelagic Fish Communities in the Mattaponi and Pamunkey Rivers, Virginia." W&M ScholarWorks, 1992. https://scholarworks.wm.edu/etd/1539617648.
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Cavalcanti, Lilian Cristina Gomes. "Avaliação genética de padrões de pelagem em ovinos da raça Crioula." reponame:Repositório Institucional da UnB, 2015. http://dx.doi.org/10.26512/2015.11.D.19814.
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Ovinos da raça Crioula são localmente adaptados ao sul do Brasil e produzem lã medulada e naturalmente pigmentada com uma alta variabilidade de cores (preto, marrom, castanho, branco e cinza) e com potencial para uso econômico na região. A compreensão dos componentes genéticos responsáveis pela coloração nessa raça poderá auxiliar a seleção de cores específicas para nichos de mercado e/ou produtores bem como irá auxiliar na composição do Banco de Germoplasma de forma a conservar a maior diversidade genética possível para essa característica. Resultados preliminares obtidos no rebanho de conservação da raça Crioula sugerem que a diversidade fenotípica para cor de pelagem se manifesta de forma bimodal (animais com cores escuras e claras). Um total de 115 animais do Núcleo de Conservação da ovelha Crioula da Embrapa Pecuária Sul (Bagé, RS) foram selecionados para compor este estudo que buscou polimorfismos nos genes MC1R, ASIP e TYRP1. Foram sequenciados um total de 953, 5.353 e 1.609 pb, respectivamente para cada gene onde foram encontrados um total de 14 marcadores de base única (SNPs). Adicionalmente, dois ensaios com primers fluorescentes foram realizados para detectar presença de duplicações e ou deleções no gene ASIP. Apenas 7 dos 115 animais testados apresentaram um padrão de pelagem que não pode ser explicado pelos polimorfismos analisados nos três genes estudados. Tais resultados sugerem que a grande variabilidade fenotípica observada na raça Crioula demandará novos estudos de forma a se explicar 100% da diversidade observada. O painel de marcadores usado nesse estudo foi eficiente o suficiente para implementar um programa de seleção assistida no Núcleo de Conservação da raça Crioula desta forma foi possível selecionar os animais que terão seu germoplasma criopreservado.
The Creole sheep is a locally adapted breed from southern Brazil that produces a medulated and naturally pigmented wool with a high variability of colors (black, chestnut, brown, white and gray) and has potential for economic use in the region. Understanding the genetic components responsible for the color in this breed will help in the selection of specific colors for niche markets and / or will assist in the composition of the Germplasm Bank to preserve highest genetic diversity for this characteristic. Preliminary results from the conservation flock of the Creole breed suggest that phenotypic diversity in coat color manifests itself in bimodal form (animals with dark and light colors). A total of 115 sheep from the Conservation Nucleus of Creole Sheep from Embrapa South Livestock (Bagé, RS) were analyzed for polymorphisms in genes MC1R, ASIP and TYRP1. A total of 953; 5,353 and 1,609 bp were analysed respectively for each gene where a total of 14 single nucleotide polymorphisms (SNPs) were found. In addition, two fluorescent assay primers were performed to detect the presence of duplication and / or deletions in the ASIP gene. Only 7 of the 115 animals showed a coat pattern that cannot be explained by polymorphisms analyzed in the three genes. These results suggest that the phenotypic variability observed in Criollo requires further studies to explain 100% of the observed diversity. The marker panel used in this study was efficient for the implemention of a marker assisted selection program in Creole Conservation Center to select animals for germplasm cryopreservation.
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Anitsakis, Erin Colleen. "Dynamics of marine pelagic bacterial communities on the Texas-Louisiana shelf." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1172.
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Pontius, Ruth Atkins. "The impact of zebra mussels (Dreissena polymorpha) on pelagic food webs." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1400072667.
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