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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Investigation into the Geodynamics of Planetary Ice-Ocean Systems: Application to Jupiter's Icy Moon Europa

January 2017 (has links)
abstract: The Jovian moon Europa's putative subsurface ocean offers one of the closest astrobiological targets for future exploration. It’s geologically young surface with a wide array of surface features aligned with distinct surface composition suggests past/present geophysical activity with implications for habitability. In this body of work, I propose a hypothesis for material transport from the ocean towards the surface via a convecting ice-shell. Geodynamical modeling is used to perform numerical experiments on a two-phase water-ice system to test the hypotheses. From these models, I conclude that it is possible for trace oceanic chemistry, entrapped into the newly forming ice at the ice-ocean phase interface, to reach near-surface. This new ice is advected across the ice-shell and towards the surface affirming a dynamical possibility for material transport across the ice-ocean system, of significance to astrobiological prospecting. Next, I use these self-consistent ice-ocean models to study the thickening of ice-shell over time. Europa is subject to the immense gravity field of Jupiter that generates tidal heating within the moon. Analysis of cases with uniform and localized internal tidal heating reveal that as the ice-shell grows from a warm initial ocean, there is an increase in the size of convection cells which causes a dramatic increase in the growth rate of the ice-shell. Addition of sufficient amount of heat also results in an ice-shell at an equilibrium thickness. Localization of tidal heating as a function of viscosity controls the equilibrium thickness. These models are then used to understand how compositional heterogeneity can be created in a growing ice-shell. Impurities (e.g. salts on the surface) that enter the ice-shell get trapped in the thickening ice-shell by freezing. I show the distribution pattern of heterogeneities that can form within the ice-shell at different times. This may be of potential application in identifying the longevity and mobility of brine pockets in Europa's ice-shell which are thought to be potential habitable niches. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2017
32

Gaming with sustainability and the life below the waves : How to stimulate a peaceful co-existence with our plante's water and the life there-in through engaging experiences

Schnell, Felizia January 2017 (has links)
In 2015 the UN completed a list of environmental and social goals, one of these goals is the “life in the water” goal, or goal 14. It focuses on the factors endangering the diversity and the ecological balance in the water. However, the goals are formulated with a focus on changes to be done by countries or bigger organisations, not by individuals. This project focused on creating a design for a technical solution that teaches and motivates youths how to help take care of the planet. To do this a design process consisting of a pre-study, concept phase and a workshop were done. The pre-study consisted of interviews, a questionnaire and a pre-study of similar digital games. The interviews focused on how youths and what values and knowledge youths are taught today. These interviews informed a questionnaire that focused on how and what the students were taught about taking care of the oceans. The last part of the pre-study was a review of games with focus on the environment, which was later used to inspire the design process. The concept phase consisted of three iteration phases of concepts and the last phase created the concept tested in the following workshop. Each iteration ended with a discussion of concepts were one or two concepts chosen to focus on. The final concept was a type of exhibition of two digital minigames or simulations and one physical simulation. The three prototypes were linked, in a wizard of Oz type of style, where two of the prototypes, the physical and one of the digital prototype, influenced the environment in the last digital prototype. The collective prototype seemed to inspire engagement and interest from the participants and was mainly received as a good idea. The workshop was held with youths between 12-16 years old and resulted in feedback and a proposition to a redesign.
33

Adaptation à la niche écologique chez deux représentants majeurs du phytoplancton marin, Synechococcus et Prochlorococcus : des gènes à l'écosystème / Niche adaptation in two major members of marine phytoplankton, Synechococcus and Prochlorococcus : from genes to ecosystem

Doré, Hugo 14 December 2017 (has links)
Les picocyanobactéries marines Prochlorococcus et Synechococcus sont les organismes photosynthétiques les plus abondants sur la planète et sont présentes dans presque tous les océans. Au cours de cette thèse, j'ai cherché à mieux comprendre les liens entre diversité génétique et adaptation à la niche écologique chez ces deux genres. Tout d'abord, l'étude de la répartition des populations de picocyanobactéries à l'échelle mondiale à l'aide d'un marqueur taxonomique très résolutif m'a permis de définir des unités taxonomiques écologiquement significatives, et d'identifier les principaux facteurs abiotiques influençant leur répartition. La deuxième partie de ce travail a visé à identifier les bases génétiques de l'adaptation des picocyanobactéries marines à des niches écologiques distinctes. L'étude comparative de 81 génomes non-redondants de ces organismes a révélé le rôle combiné des gains et pertes de gènes et des substitutions d'acides aminés dans la diversification des deux genres, et l'analyse de la répartition des gènes de picocyanobactéries marines dans l'océan mondial m'a permis de montrer que chaque communauté, adaptée à un environnement donné, possède un répertoire de gènes distinct. Enfin, le dernier volet de cette thèse a consisté en la caractérisation physiologique et transcriptomique de cinq souches de Synechococcus soumises à des stress lumineux et thermique afin d'analyser la variabilité écotypique de la réponse au stress. Les résultats obtenus au cours de cette thèse ont donc permis d'améliorer notre connaissance des niches écologiques occupées par les picocyanobactéries marines, et de mieux comprendre les mécanismes leur ayant permis de s'y adapter. / The marine picocyanobacteria Synechococcus and Prochlorococcus are the two most abundant photosynthetic organisms on earth and are present in almost all oceans. During this PhD thesis, I explored the links between genetic diversity and niche adaptation in these two genera. First, the analysis of the distribution of picocyanobacterial populations at the global scale using a high-resolution taxonomic marker allowed me to define ecologically significant taxonomic units, to improve the delineation of their ecological niches and to identify the main abiotic factors influencing their in situ distribution. The second part of this work aimed at identifying the genetic bases of adaptation of marine picocyanobacteria to distinct niches. The comparative analysis of 81 non-redundant genomes of these organisms revealed the combined role of gene gains and losses and of substitutions in protein sequences in the diversification of both genera, and the analysis of the distribution of all known picocyanobacterial genes in the global ocean allowed me to show that each community, adapted to specific environmental conditions, possesses a distinct gene repertoire. Finally, the last part of this work has consisted in the physiological and transcriptomic characterization of five Synechococcus strains, which were submitted to light and thermal stresses in order to better understand the ecotypic variability of the stress response in this genus. Altogether, results obtained during this PhD provided many new insights into the ecological niches occupied by marine picocyanobacteria and the mechanisms allowing them to adapt to these various niches.
34

Statistical Analysis of Wave Parameters

Lindberg, Martin January 2023 (has links)
In this study, several wave parameters are downloaded or calculated from spectral wave data, and their interdependence is investigated. A literature review is carried out to summarize these dependencies. The literature study is followed by a statistical analysis of the relations between the calculated wave parameters. This statistical analysis is done both for all wave data, resulting in a global expression for the relations, and for the different seas and oceans, resulting in a deeper analysis about local differences and how these differences should be taken into consideration when using wave parameter relations in specific water bodies.
35

Vital Coasts, Mortal Oceans: The Pearl Button as Media Environmental Philosophy

Holtmeier, Matthew 10 July 2019 (has links)
In The Pearl Button, Patricio Guzman explores the role water played in shaping how the Selk’nam inhabited the coasts of the Tierra del Fuego in Patagonia through “cosmovisions,’ sequences that extend beyond human perception, even as they link the habitation of indigenous peoples to subsequent colonial and political projects. Guzman’s “cosmovisual aesthetic” warrants dissection in the form of a video essay because of its complicated interplay between editing and shot distance, which establishes a critical bioregionalism that acknowledges the unique qualities of place, here the Tierra del Fuego, as well as the forces of globalization that threaten it. Guzman’s cosmovisual aesthetic ranges from extreme close-ups to reveal minute details in objects to aerial shots that articulate the shapes of coasts and even to telescopic shots depicting planets and nebulae. He works with archival photography and the superimposition of images/sounds in order to create a pluriverse of peoples and environments, which moves beyond human audiovisual and temporal perception. In doing so, The Pearl Button links the ways in which the Selk’nam inhabited Chile, depending on its waters, to the ocean as the source of the colonial project of Spain and site of political murders under the later dictatorship of Augusto Pinochet. Guzman’s cinematic elaboration of Indigenous worldviews resonates with contemporary Chilean philosophers Humberto Maturana, Francisco Varela, and Ricardo Rozzi. From cybernetics to ecological philosophy, this video essay weaves the insights of these Chilean philosophers with Guzman’s cosomovisions in order to highlight the complex ecological insights at the intersection of Indigenous thought and film form. In particular, it extends Rozzi’s practical model of Field Environmental Philosophy to communicating ecological philosophy through media.
36

Strategi för framgång : Hur svenska storföretag arbetar för att hävda sig mot konkurrens och skapa nya marknader

Zilling, Isabelle January 2019 (has links)
Syfte: Med ”Blue Ocean Strategy” avses skapandet av nya marknader utan konkurrens. Denna studie vill belysa hur fem svenska storföretag aktivt arbetar med att skapa nya marknader, stå emot konkurrens på befintlig marknad och slutligen om miljöarbete ses som en konkurrensfördel, vilket leder till en stärkt marknadsposition.   Metod: Studien angriper undersökningsproblemet med att anta en induktiv ansats med kvalitativa intervjuer. Arbetet baseras på djupintervjuer med företagsledare från fem svenska storföretag; Alfa Laval, Assa Abloy, Inwido, Lindab och Tetra Pak. Vidare antar studien ett hermeneutiskt förhållningssätt där tolkningen blir central. Resultat och konklusion: Resultatet av studien visar att få företag verkar för att inta en ny oetablerad marknad, så kallad ”blå ocean”. Fokus hos företagen i studien ligger på att bibehålla samt vinna nya marknadsandelar på befintliga marknader samt utöka till fler geografiska områden. Studien visar hur företagen arbetar både med kostnadsöverlägsenhet samtidigt som de arbetar med differentiering av sina produkter där samtliga företag idag arbetar med innovationsarbete vilket skapar möjligheter för att särskilja produkter från konkurrenters utbud. Detta till trots är företagen inte ”stuck in the middle” enligt Porters (1980) teori, utan stöder tesen om en hybridstrategi som visar på god konkurrenskraft om företaget är innovativt. Utöver det belyser studien digitaliseringens intåg på marknaden där både marknadsföring och handel i allt större utsträckning sker digitalt. Företagen i studien visar också på betydelsen av lokal närvaro, inträde på rätt geografiska marknader och värdet av goda kundrelationer. Slutligen belyses nödvändigheten att vara ledande avseende miljöfrågor och hållbara produkter. / Purpose: The “Blue Ocean Strategy” refers to the creation of new markets identified by no competition. This study highlights how five big Swedish corporations actively work to create new markets, resist competition on the existent market and if environmental work is seen as a competitive advantage, and thereby create a strengthened market position. Method: The study uses an inductive approach with qualitative interviews. The work is based on thorough interviews with corporate leaders from five big Swedish corporations; Alfa Laval, Assa Abloy, Inwido, Lindab and Tetra Pak. The study takes a hermeneutic approach in which interpretation becomes central. Result and conclusion: The result of the study shows that only few corporations work to create a new market or “Blue Ocean”. The focus of the studied corporations is to maintain their current market shares and to win new market shares on already existing markets. Their focus is also to expand into more geographical areas. The study describes how the corporations work with both overall cost leadership and at the same time with differentiation of their products. All corporations work with innovation, which creates possibilities to distinguish their products from competitors. Despite this, corporations are not “stuck in the middle” in accordance with Porter’s (1980) theories; instead they support the modification of a hybrid strategy, which shows strong competitiveness if the corporation is innovative. Further the study has identified the entry of digitalisation in which both marketing and trade more frequent occur digitally. The study also identifies the importance of local presence, the right geographical market entry and the value of good customer relationships. Finally the study illustrates the necessity to be in a leading position regarding environmental and sustainable products.
37

Iodine Isotopes and their Species in Surface Water from the North Sea to the Northeastern Atlantic Ocean

He, Peng January 2013 (has links)
Huge amounts of anthropogenic 129I have been and still are released to the environment through liquid and gaseous discharges from the nuclear fuel reprocessing facilities worldwide and in particular the ones in Europe. Most of this 129I signal has been accumulated in the marine environment which plays a major role in the iodine natural pool.  In this thesis, an overview of available 129I concentrations in waters of the oceans and marginal seas together with new data about 129I and 127I spatial distribution in surface seawater along a transect between the North Sea and the northeastern Atlantic Ocean are presented. After comprehensive chemical separation, the concentrations of iodine isotopes (127I and 129I) and their species (iodide and iodate) were analysed using accelerator mass spectrometry and inductively-coupled plasma mass spectrometry. The results show that, generally, changes in the 127I and 127I-/127IO3- are comparable to data from other marine waters which are related to natural distribution patterns. A considerable variation of 129I along the transect is observed with the highest values occurring in the eastern English Channel and relatively low values obtained in the northeastern Atlantic Ocean. Inventory estimations of 129I in the North Sea and the English Channel are 147 kg and 78 kg, respectively, where more than 90% resides in the Southern Bight and the eastern English Channel. Iodate is the dominant iodine species for both 127I and 129I in most seawater samples from the North Sea to the Atlantic Ocean. 129I species variability suggests a slow process of 129I- oxidation in the open sea. It takes at least 10 years for the 129I-/129IO3- pair to reach their natural equilibrium as the water is transported from the English Channel. The results suggest a main transport of 129I from the western English Channel via the Biscay Bay into the northeastern Atlantic Ocean. Further, high 129I/127I and distinctive 129I-/129IO3- values south of 40°N indicate possible contribution of 129I through Mediterranean Outflow Water. The environmental radioactive impact of 129I and possible applications in ecosystem studies are also discussed.
38

Regional Fisheries Management Organizations: is power listening to Science? / Organizações Regionais para o Ordenamento Pesqueiro: o poder está ouvindo a ciência?

Gonçalves, Leandra Regina 19 September 2016 (has links)
One of the biggest challenges in contemporary global environmental governance is the future of marine biodiversity. Over the years, increased fishing efforts in previously remote areas drove many fish stocks to scarcity. The Regional Fisheries Management Organizations (RFMOs) emerged to solve the international fishery crisis, on the assumption that they would provide a forum where Member States may agree and discuss binding rules for the conservation and management of fish stocks within its geographical area of responsibility. Although some agreements existed for more than 60 years, many authors agree that they have not been fully effective in promoting the maintenance and conservation of fish stocks. There are many reasons that might explain the lack of effectiveness, one of them being that science is not very often listened to in the political decision-making process. In this research, the influence of knowledge and science in shaping policy decisions will be observed and analyzed. Therefore, the use of the epistemic communities theory, that which forms part of the constructivist turn in international relations -- was used to answer the main question posed here: when does power listen to science? When it does, does it bring more effectiveness in terms of knowledge, input from epistemic communities, does it induce states to change their behavior, and do these influences lead to policies, which can credibly improve biomass? Using process tracing, through elite interviews, and with a systematic compilation and study of meeting reports from three RFMOs: the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR); the International Convention for the Conservation of Atlantic Tunas (ICCAT); and the Commission for the Conservation of Southern Bluefin Tuna (CCSBT), the final conclusion is that they may listen to science, but their strategy, allies, and the ways in which it occurs differ case-by-case. / Um dos maiores desafios na governança ambiental global contemporânea é o futuro dos ecossistemas e da biodiversidade marinha. Ao longo dos anos, o aumento do esforço de pesca nas áreas anteriormente remotas levou muitas populações de peixes à escassez. As Organizações Regionais para o Ordenamento Pesqueiro (OROPs) surgiram para resolver a crise internacional de pesca, através um fórum onde os Estados-Membros podem acordar e discutir regras vinculativas para a conservação e gestão dos recursos pesqueiros no âmbito da sua área geográfica de responsabilidade. Embora alguns acordos existam há mais de 60 anos, muitos pesquisadores concordam que os mesmos não têm sido totalmente eficazes para promover a manutenção e conservação dos recursos pesqueiros. Muitas razões podem explicar a falta de eficiência no manejo, uma delas é que, o aconselhamento cientifico não é muitas vezes considerado nas decisões políticas. Nesta pesquisa, a influência do conhecimento e da ciência na tomada de decisões políticas serão avaliadas. Para isso, a teoria das comunidades epistêmicas, que faz parte da veia construtivista em Relações Internacionais, foi usada para responder à principal questão colocada aqui: quando é que o poder ouviu a ciência? E isso trouxe mais eficiência em termos do conhecimento proveniente das comunidades epistêmicas induzir os Estados a mudarem seu comportamento e a influência levar a políticas que aumentem a biomassa dos estoques pesqueiros? Com o uso de process tracing, por meio de entrevistas com atores e uma compilação sistemática dos relatórios das reuniões anuais, as OROPS: CCAMLR, ICCAT e CCSBT foram estudadas, e a conclusão final é que, os tomadores de decisão podem ouvir a ciência, porém, a estratégia, os aliados e a forma como a influência se desenvolve varia caso a caso.
39

Seabed biotope characterisation based on acoustic sensing

Kloser, Rudolf J January 2007 (has links)
The background to this thesis is Australia’s Oceans Policy, which aims to develop an integrated and ecosystem-based approach to planning and management. An important part of this approach is the identification of natural regions in regional marine planning, for example by establishing marine protected areas for biodiversity conservation. These natural regions will need to be identified on a range of scales for different planning and management actions. The scale of the investigation reported in this thesis is applicable to spatial management at 1 km to 10 km scale and monitoring impacts at the 10s of m to 1 km biotope scale. Seabed biotopes represent a combination of seabed physical attributes and related organisms. To map seabed biotopes in deep water, remote sensing using a combination of acoustic, optical and physical sensors is investigated. The hypothesis tested in this thesis is that acoustic bathymetry and backscatter data from a Simrad EM1002 multi-beam sonar (MBS) can be used to infer (act as a surrogate of) seabed biotopes. To establish a link between the acoustic data and seabed biotopes the acoustic metrics are compared to the physical attributes of the seabed in terms of its substrate and geomorphology at the 10s m to 1 km scale using optical and physical sensors. At this scale the relationship between the dominant faunal functional groups and both the physical attributes of the seabed and the acoustic data is also tested. These tests use data collected from 14 regions and 2 biomes to the south of Australia during a voyage in 2000. Based on 62 reference sites of acoustic, video and physical samples, a significant relationship between ecological seabed terrain types and acoustic backscatter and bathymetry was observed. / These ecological terrain types of soft-smooth, soft-rough, hard-smooth and hard-rough were chosen as they were the most relevant to the biota in their ability to attach on or burrow into the seabed. A seabed scattering model supported this empirical relationship and the overall shape of backscatter to incidence angle relationship for soft and hard seabed types. The correlation between acoustic data (backscatter mean and standard deviation) and the visual and physical samples was most consistent between soft-smooth and hard-rough terrain types for a large range of incidence angles (16o to 70o). Using phenomenological backscatter features segmented into 10 common incidence angle bins from -70o to 70o the length resolution of the data decreased to 0.55 times depth. The decreased resolution was offset by improved near normal incidence (0o to 30o) seabed type discrimination with cross validation error reducing from 32% to 4%. A significant relationship was also established between the acoustic data and the dominant functional groups of fauna. Faunal functional groups were based on the ecological function, feeding mode and substrate preference, with 8 out of the 10 groups predicted with 70% correctness by the four acoustically derived ecological terrain types. Restricting the terrain classification to simple soft and hard using the acoustic backscatter data improved the prediction of three faunal functional groups to greater than 80%. Combining the acoustic bathymetry and backscatter data an example region, Everard Canyon, was interpreted at a range of spatial scales and the ability to predict the preferred habitat of a stalked crinoid demonstrated. / Seabed terrain of soft and hard was predicted from the acoustic backscatter data referenced to a common seabed incidence angle of 40o. This method of analysis was selected due to its combined properties of high spatial resolution, consistent between terrain discrimination at the widest range of incidence angles and consistent data quality checking at varying ranges. Based in part on the research reported in this thesis a mid-depth Simrad EM300 multibeam sonar was purchased for use in Australian waters. A sampling strategy is outlined to map all offshore waters with priority within the 100 m to 1500 m depths.
40

Regional Fisheries Management Organizations: is power listening to Science? / Organizações Regionais para o Ordenamento Pesqueiro: o poder está ouvindo a ciência?

Leandra Regina Gonçalves 19 September 2016 (has links)
One of the biggest challenges in contemporary global environmental governance is the future of marine biodiversity. Over the years, increased fishing efforts in previously remote areas drove many fish stocks to scarcity. The Regional Fisheries Management Organizations (RFMOs) emerged to solve the international fishery crisis, on the assumption that they would provide a forum where Member States may agree and discuss binding rules for the conservation and management of fish stocks within its geographical area of responsibility. Although some agreements existed for more than 60 years, many authors agree that they have not been fully effective in promoting the maintenance and conservation of fish stocks. There are many reasons that might explain the lack of effectiveness, one of them being that science is not very often listened to in the political decision-making process. In this research, the influence of knowledge and science in shaping policy decisions will be observed and analyzed. Therefore, the use of the epistemic communities theory, that which forms part of the constructivist turn in international relations -- was used to answer the main question posed here: when does power listen to science? When it does, does it bring more effectiveness in terms of knowledge, input from epistemic communities, does it induce states to change their behavior, and do these influences lead to policies, which can credibly improve biomass? Using process tracing, through elite interviews, and with a systematic compilation and study of meeting reports from three RFMOs: the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR); the International Convention for the Conservation of Atlantic Tunas (ICCAT); and the Commission for the Conservation of Southern Bluefin Tuna (CCSBT), the final conclusion is that they may listen to science, but their strategy, allies, and the ways in which it occurs differ case-by-case. / Um dos maiores desafios na governança ambiental global contemporânea é o futuro dos ecossistemas e da biodiversidade marinha. Ao longo dos anos, o aumento do esforço de pesca nas áreas anteriormente remotas levou muitas populações de peixes à escassez. As Organizações Regionais para o Ordenamento Pesqueiro (OROPs) surgiram para resolver a crise internacional de pesca, através um fórum onde os Estados-Membros podem acordar e discutir regras vinculativas para a conservação e gestão dos recursos pesqueiros no âmbito da sua área geográfica de responsabilidade. Embora alguns acordos existam há mais de 60 anos, muitos pesquisadores concordam que os mesmos não têm sido totalmente eficazes para promover a manutenção e conservação dos recursos pesqueiros. Muitas razões podem explicar a falta de eficiência no manejo, uma delas é que, o aconselhamento cientifico não é muitas vezes considerado nas decisões políticas. Nesta pesquisa, a influência do conhecimento e da ciência na tomada de decisões políticas serão avaliadas. Para isso, a teoria das comunidades epistêmicas, que faz parte da veia construtivista em Relações Internacionais, foi usada para responder à principal questão colocada aqui: quando é que o poder ouviu a ciência? E isso trouxe mais eficiência em termos do conhecimento proveniente das comunidades epistêmicas induzir os Estados a mudarem seu comportamento e a influência levar a políticas que aumentem a biomassa dos estoques pesqueiros? Com o uso de process tracing, por meio de entrevistas com atores e uma compilação sistemática dos relatórios das reuniões anuais, as OROPS: CCAMLR, ICCAT e CCSBT foram estudadas, e a conclusão final é que, os tomadores de decisão podem ouvir a ciência, porém, a estratégia, os aliados e a forma como a influência se desenvolve varia caso a caso.

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