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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.
41

On the application of detached eddy simulation turbulence modelling to hydrocyclonic separators for shipboard ballast water treatment

McCluskey, D. K. January 2009 (has links)
There is significant worldwide environmental concern related to the transportation of Invasive Aquatic Species (IAS) by ships ballast water into non-native environments. This has given rise to the development of a vast array of technological ballast water treatment systems. The complex environmental challenges and tight operational characteristics of marine vessels limits the scope of the technologies used for Ballast Water Treatment (BWT). As a result few technologies have progressed beyond the research and development stage; however one of the most promising technologies for ship board use is the cyclonic separator, or hydrocyclone. Despite the use of hydrocyclones in a wide variety of engineering applications they have yet to be successfully adapted towards the removal of suspended sediment and marine organisms from large volumes of ballast water. The following primary objectives of this study have been met: • Via critical review identify the technological solutions for treating ballast water best suited to onboard use. • Define the critical flow regimes evident within hydrocyclonic separators. • Establish a series of Computational Fluid Dynamics (CFD) simulations, evaluating standard turbulence models in order to determine the capacity for commercial CFD to model hydrocyclonic flow. This study has detailed the operational characteristics of ballast water hydrocyclones with the aim of enabling hydrocyclones to be optimised for individual ship configurations. Flow simulations have been conducted using CFD, and in particular the Detached Eddy Simulation (DES) turbulence model. Finally the DES model is shown to be a legitimate turbulence model for hydrocyclonic flow regimes, validated against empirical and experimental data.
42

Atividade antiviral de extratos de organismos marinhos utilizando como modelo os vírus da doença de Newcastle e Metapneumovirus aviário / Antiviral activity of marine organisms extracts using as model Newcastle disease virus and avian Metapneumovirus

Sakata, Sonia Tatsumi, 1978- 22 August 2018 (has links)
Orientadores: Clarice Weis Arns, Luciana Konecny Kohn / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T17:08:20Z (GMT). No. of bitstreams: 1 Sakata_SoniaTatsumi_M.pdf: 14113239 bytes, checksum: 26dfdfbc0c87c2a3a37c6143072df6c6 (MD5) Previous issue date: 2013 / Resumo: Produtos naturais isolados a partir de invertebrados e organismos marinhos tem sido objeto de pesquisas contínuas ao longo dos últimos cinquenta anos, principalmente devido à sua complexidade estrutural e potentes atividades biológicas. O presente trabalho teve como proposta ampliar e aprofundar a investigação de substâncias bioativas em extratos de organismos marinhos, junto ao IQSC-USP/Projeto temático, realizando bioensaios de atividade antiviral no laboratório de virologia da Unicamp. Com o objetivo de realizar uma triagem para pesquisar substâncias com ação antiviral, foram eleitas duas espécies de vírus de destaque na avicultura, o Metapneumovirus aviário (aMPV) e o vírus da Doença de Newcastle (NDV), representantes da família Paramyxoviridae. As propriedades em comum dos vírus dentro das respectivas subfamílias, como a organização genômica, sequências das proteínas e suas atividades biológicas, permitem a utilização do aMPV como modelo de estudo para importantes agentes infecciosos da subfamília Pneumovirinae, e o NDV da subfamília Paramyxovirinae. Para a triagem de compostos antivirais foi realizada a avaliação in vitro na linhagem celular Chicken Embryo Related (CER) para a propagação dos vírus e analisar os resultados de inibição viral frente a diferentes extratos e substâncias. Dos cento e vinte e cinco extratos testados frente ao aMPV, sete demonstraram ser ativos, e seis com alto potencial antiviral. Inicialmente, cento e quarenta e sete extratos foram testados frente ao NDV, porém, o resultado foi inconclusivo devido a problema com o título da amostra viral. Assim, os sete extratos ativos e os seis com alto potencial antiviral contra o aMPV foram testados quanto à capacidade de inibição do NDV. Apesar das similaridades dos vírus da família Paramyxoviridae, os extratos não tiveram atividade contra o NDV, como ocorreu frente ao aMPV. As amostras ativas foram estudadas em três tipos de tratamento a fim de determinar os possíveis mecanismos de ação dos extratos: Pré-tratamento, fases de adsorção e/ou penetração do vírus na célula; Pós-tratamento, etapas intracelulares de replicação do vírus; e Inativação Viral. Pela análise visual do efeito citopático, os sete extratos ativos contra aMPV, quatro interrompem as etapas intracelulares de replicação do vírus, dois agem nas fases de adsorção e/ou penetração do vírus à célula, e um não tinha quantidade suficiente para realizar o teste. Com a finalidade de avaliar os possíveis mecanismos de ação com maior objetividade, menor risco de contaminação e alta especificidade, testou-se a metodologia de reação em cadeia da polimerase (PCR) em tempo real. Utilizando um composto puro (pirocina A) frente ao aMPV em CER, a metodologia se demonstrou eficiente. Esse dado foi confirmando pela diminuição de RNA viral quando ocorre a atividade antiviral, dando indícios de atuação do composto em etapas intracelulares de replicação do aMPV. A detecção de extratos com atividade antiviral nas situações testadas neste trabalho corrobora o valor da biodiversidade marinha como fonte de produtos promissores na terapêutica de enfermidades virais. Portanto, a necessidade de estudos sobre esses vírus e do desenvolvimento de novos insumos a serem utilizados nos seus controles é de grande importância ponderado a crescente projeção da indústria avícola brasileira no comércio mundial / Abstract: Natural products isolated from invertebrates and marine organisms have been studied over the past fifty years, mainly due to their structural complexity and potent biological activities. This project was proposed to broaden and deepen the research of bioactive substances in extracts of marine organisms, with the IQSC-USP group, performing bioassays antiviral activity in the laboratory of virology at Unicamp. In order to perform a screening to search antiviral substances were elected two species prominent in poultry, the avian Metapneumovirus (aMPV) and Newcastle disease virus (NDV), representatives of the family Paramyxoviridae. The common properties of the virus within their respective subfamilies, such as genomic organization, sequences of proteins and their biological activities, allow the use of aMPV as a study model for important infectious agents of Pneumovirinae subfamily, and NDV Paramyxovirinae subfamily. For antiviral screening, compounds were tested in vitro using Chicken Embryo Related (CER) cell lineage for the propagation of the virus and analyze the results of viral inhibition against various substances. Among one hundred twenty five extracts tested against aMPV, seven were actives and six have been shown high antiviral potential against the virus. Initially, one hundred fourty seven extracts were tested against NDV. However, the result was inconclusive due to problems with the titer of the viral sample. Thus, the seven active extracts and six extracts with high antiviral potential against the aMPV were tested for the ability to inhibit NDV. Despite the similarities of viruses of the family Paramyxoviridae, the extracts had no activity against NDV, as occurred against aMPV. The active samples were studied in three types of treatment in order to determine the possible mechanisms of action of the extracts: Pre-treatment, stages of adsorption and / or penetration of the virus into the cell; Post-treatment, intracellular steps of virus replication; and Viral Inactivation. At visual analysis of cytopathic effect, from all 7 extracts active against aMPV, 4 disrupt intracellular steps of virus replication, 2 acts on adsorption and / or penetration stages of the virus into the cell, and 1 was not enough to perform the test. In order to assess the possible mechanisms of action more objectively, lower contamination risk and high specificity, the polymerase chain reaction (PCR) in real time methodology was tested. Using a pure compound (pirocina A) against aMPV in CER cell lineage, the methodology is demonstrated efficient. This was confirmed by the decrease of viral RNA when occurs antiviral activity, an evidence of compound's action on intracellular steps of aMPV replication. The detection of extracts with antiviral activity in this study confirms the value of marine biodiversity as a source of promising products in the viral diseases therapeutic. Therefore, the primordiality for more studies and the development of new inputs to control these viruses is extremely important to increasing of Brazilian poultry industry in world trade / Mestrado / Microbiologia / Mestra em Genética e Biologia Molecular
43

The potential for using biomonitoring in the Hong Kong marine environment

Yu, Pui-shan., 余珮珊. January 1996 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
44

Biological monitoring and its value in assessing the marine environment of Hong Kong

Tsui, Man-leung., 徐文亮. January 1996 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
45

The effects of sympatric and allopatric hab species on calanoid copepod swimming behavior

Nagel, Kathryn 13 January 2014 (has links)
Harmful algal blooms, commonly referred to as red tides, occur yearly with dramatic impacts on marine ecology, coastal economies, and human health. As a consequence, research into the zooplankton grazers that consume HABs is highly important. However, changes in ocean temperature may increase the range of many HABs, exposing historically naive copepods to new species and their associated chemicals. Little research into the impact of allopatric verses sympatric species, particularly on the immediate behavioral impact, has been performed, leaving the indirect fitness effects of HAB exposure and consumption relatively unknown. We measured alterations in the swimming behavior of the calanoid copepod Temora longicornis following exposure to sympatric Alexandrium fundyense and allopatric Karenia brevis treatments. After a 15-16 hours depuration period postA. fundyense exposure, T. longicornis exhibited increased average swimming speed and an elevated net to gross displacement ratio (NGDR). During exposure toK. brevis, copepods exhibited an immediate decrease in swimming speed and NGDR, as well as an increased frequency of jump behavior. However, these effects faded after an one-hour depuration period, and disappeared after a 15-16 hour depuration period. The alterations in swimming behavior demonstrated by the copepods treated A. fundyense may increase encounter rate with predators, while copepods treated with K. brevis remain in bloom conditions for longer periods of time, negatively affecting survivorship. Temora longicornis individuals also may be made more visible to predators due to the increase in jumps seen during treatment with K. brevis. These behavioral changes suggest how HABs escape from zooplankton grazer control by altering copepod swimming behavior, and the pattern of predator-prey evolution that occurs over time.
46

Estudo químico dos organismos marinhos Aplysina fistularis Pallas e Sargassum polyceratium Montagne.

Lira, Narlize Silva 06 August 2012 (has links)
Made available in DSpace on 2015-05-14T12:59:39Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 5219644 bytes, checksum: 21dfe60a9b7bfb0358d99227ad19922d (MD5) Previous issue date: 2012-08-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Algae and marine sponges have been the targets of important scientific researches in the last 50 years, with a large number of secondary metabolites isolated and identified, showing a wide structural variety where certain compounds are useful in characterizing classes of algae and sponges fact of great importance for chemists, taxonomists and ecologists. These substances exhibit many biological activities, such as defense against consumers and competitors, and colonial and pathogen organisms; or they display reproductive function. This thesis describes the results from the chemical study of Sargassum polyceratium Montagne, a seaweed from the Sargassaceae family, and Aplysina fistularis Pallas, a marine sponge from the Aplysinidae family. Both species had their chemical constituents identified by spectroscopic methods such as IR, mass and 1H and 13C-1D and -2D NMR, and by comparison with literature. The following porphirinic derivatives were isolated from S. polyceratium: 132-hydroxy-(132-R)-phaephytin a, 132-hydroxy-(132-S)-phaeophytin a,phaeophytin a and the steroid fucosterol. The chemical study of A. fistularis led us to the reisolation of the alkaloid and acetamide: 2-(3,5-dibromo 4methoxypheny,N,N,Ntrimethylethanamonium and (3,5-dibromo-4-ethoxy-1-hydroxy-4-methoxycyclohexa-2,5-dienyl) acetamide, and to the isolation of alkaloid 3,5-dibromo-4-[3 dimethylamonium]propoxyphenyl]-N,N,N trimethylethanamonium (aplysfistularine),reported for the first time. The ethanolic extract from S. polyceratium was evaluated for psicopharmacological effects, showing behavioral changes of CNS depressant type. The ethanolic, hexanic and dichloromethanic extracts as well as the mixture (132-hydroxy-(132-R)-phaephytin a and 132-hydroxy-(132-S)-phaeophytin a) were not capable of inhibiting the growth of the tested lineages, showing negative antimicrobial activity. However they were capable of modifying the antibiotic activity, modulating the bacterial resistance between 2x to 4x. The isolated compounds from A. fistularis show inhibition of the DNA enzyme Topoisomerase II-α, with further biological studies needed for determining the compounds potency. Therefore, the present results contribute for the chemical study of marine organisms from species S. polyceratium and A. fistularis. / As algas e as esponjas marinhas têm sido alvos de pesquisas científicas importantes nos últimos 50 anos, de onde foram isolados e caracterizados um grande número de metabólitos secundários, com ampla variedade estrutural, determinadas substâncias podem caracterizar as classes de algas e esponjas, fato de grande importância para os químicos, taxonomistas e ecologistas. Estas substâncias exercem inúmeras atividades biológicas, como: defesa contra consumidores, competidores, organismos coloniais e patógenos ou apresentam função reprodutiva. Este trabalho descreve os resultados do estudo químico dos organismos marinhos Sargassum polyceratium Montagne e Aplysina fistularis Pallas, uma alga marinha da família Sargassaceae e uma esponja marinha da família Aplysinidae, respectivamente. Os constituintes químicos foram identificados através da análise de dados obtidos por métodos espectroscópicos como infravermelho, massas e ressonância magnética nuclear de 1H e 13Cuni e bidimensionais, além de comparação com valores da literatura. Da espécie S. polyceratium foram isolados os derivados porfirínicos: 132-hidroxi-(132-R)-feofitina a, 132- hidroxi-(132-S)-feofitina a, feofitina a e o esteróide fucosterol. O estudo químico da A.fistularis resultou no reisolamento do alcaloide e da acetamida: 2-(3,5-dibromo-4- metoxifenil)-N,N,N-trimetiletanamônio e (3,5-dibromo-4-etoxi-1-hidroxi-4-metoxicicloexa-2,5-dienila) acetamida, e no isolamento do alcaloide 3,5-dibromo-4-[3 dimetilamônio]propoxifenil]-N,N,N-trimetiletanamônio (aplysfistularina), aqui descrito pela primeira vez. A avaliação dos efeitos psicofarmacológicos do extrato etanólico do S. polyceratium induziu alterações comportamentais, do tipo depressora do SNC. Os extratos etanólico, hexânico, diclorometânico e a mistura (132-hidroxi-(132-R)-feofitina a e 132-hidroxi-(132-S)-feofitina a) não foram capazes de inibir o crescimento das linhagens testadas, apresentando atividade antimicrobiana negativa. Porém foram capazes de modificar a atividade antibiótica, diminuindo entre 2x à 4x a resistência bacteriana. As substâncias isoladas da A. fistularis mostraram inibição da enzima DNA Topoisomerase II-α, sendo necessárias outras avaliações biológicas para determinar a potência dos compostos. Assim, os resultados obtidos neste trabalho contribuíram para o estudo químico dos organismos marinhos das espécies S. polyceratium e A. fistularis.
47

Genetic connectivity, adaptation, and phenotypic plasticity of corals and anemones under thermal stress

Rivera, Hanny Elizabeth. January 2019 (has links)
Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2019 / Cataloged from PDF version of thesis. / Includes bibliographical references. / Under global climate change, our oceans are warming at an unprecedented rate. Increased temperatures represent a severe source of stress for many marine organisms. This thesis aims to understand how corals and anemones respond to changing temperatures across different timescales and investigates mechanisms that can facilitate persistence in light of environmental change, from selection and adaptation across generations to phenotypic plasticity within a single individual's lifespan. In this context, I explore three case studies of thermal stress in corals and anemones. I begin with massive Porites lobata corals from the central Pacific. Here, reefs that are most affected by El Niflo, such as Jarvis and the northeast Phoenix Islands maintain genetic diversity indicating recruitment from nearby reefs may occur. Yet, they show significant genetic differentiation (FsT) from farther areas, suggesting this dispersal may be limited. / Thermal variability in this region may also favor plasticity over adaptation, as we do not find differences in bleaching histories among genetic groups. Next, I investigate genetic connectivity and adaptation to chronically elevated temperatures across a natural temperature gradient within the Palauan archipelago. Combining genetic data and historical growth measurements from coral cores, I find that Palau's warmest reefs harbor unique genetic subpopulations of Porites lobata and find evidence for a genetic basis of their higher thermal tolerance. Lastly, I explore if parents can modulate parental effects to increase the thermal tolerance of their offspring over short time scales, using the estuarine anemone Nematostella vectensis. Indeed, I find parents exposed to increased temperatures quickly produce more thermally tolerant larvae. In fact, offspring from these Massachusetts parents show thermal thresholds that are indistinguishable from more southern populations. / This thesis highlights the ability and potential of corals and anemones to persist under variable conditions over different timescales. Nevertheless, a compelling effort to reduce rates of warming worldwide will be imperative to the survival and integrity of key marine ecosystems such as coral reefs. / Funding for this research came from the National Science Foundation (Awards OCE- 1537338, OCE-1605365, OCE-1220529, and OCE-1031971), the Link Foundation, Bermuda Institute of Ocean Sciences Grants-in-Aid, the Tiffany & Co. Foundation, the Nature Conservancy, the Dalio Foundation, Inc., through the Dalio Explore Fund, and Ray Dalio through the WHOI Access to the Sea Fund, all to Anne Cohen; and a Gordon and Betty Moore Foundation grant (#4033) to Ann Tarrant / by Hanny Elizabeth Rivera. / Ph. D. / Ph.D. Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution)
48

The regional and depth distribution of Dungeness crab, <i>Cancer magister</i>, off the west coast of Washington state

Canright, Elizabeth 22 June 2022 (has links)
No description available.
49

A sea of contested evidence: Disputes over coastal pollution in Hout Bay, Cape Town, South Africa

Beukes, Amy 23 June 2022 (has links)
The City of Cape Town's (CoCT) wastewater management system discharges effluent from households, industries and other sources into the Atlantic Ocean through deep-water marine outfalls in Green Point, Camps Bay and Hout Bay. At total capacity, these three outfalls discharge 55.3 megalitres (Ml) into marine receiving environments daily. With minimal pre-treatment that amounts to screening and sieving, this results in microbial and chemical pollution of the sea (including chemicals of emerging concern), marine organisms, recreational beaches, and Marine Protected Areas (MPAs). This research focuses on contestations over evidence of that pollution in Hout Bay. The study documents the work of independent scientists seeking to provide evidence of coastal pollution obtained via microbial and chemical analyses of water (coastal and inland) and marine organisms (Mytilus galloprovincialis) samples. It also presents accounts of pollution obtained via ethnographic research with local residents, fishers, frequent water users and river activists who have observed and experienced poor coastal water quality. However, the form of evidence that is considered and informs decision-making processes by the CoCT has consistently sought to invalidate these forms of evidence, from both independent scientists and the public. Debates around knowledge of water and contests over evidence that highlight the entanglements of science, politics, and ways of knowing make visible a consistent pattern in coastal water-quality governance by the City, which results in inaction regarding the ever-growing issue of coastal pollution in Cape Town.

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