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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.
101

Gestão de recursos hídricos da Paraíba : o caso do açude Epitácio Pessoa (o Boqueirão)

Toscano, Artêmis de Araujo Oliveira 20 September 2018 (has links)
Submitted by Rosina Valeria Lanzellotti Mattiussi Teixeira (rosina.teixeira@unisantos.br) on 2018-10-31T12:42:09Z No. of bitstreams: 1 Artemis de Araujo Oliviera Toscano.pdf: 1384222 bytes, checksum: 5b5f684cd30597d91155e450286ed0c1 (MD5) / Made available in DSpace on 2018-10-31T12:42:10Z (GMT). No. of bitstreams: 1 Artemis de Araujo Oliviera Toscano.pdf: 1384222 bytes, checksum: 5b5f684cd30597d91155e450286ed0c1 (MD5) Previous issue date: 2018-09-20 / O Açude Epitácio Pessoa, conhecido popularmente como ¿O Boqueirão¿, está situado no Estado da Paraíba dentro da Bacia Hidrográfica do Rio Paraíba, localizado em áreas do semiárido paraibano, onde são registrados os menores índices pluviométricos do Brasil. Sua construção aconteceu nos anos 50, pelo Departamento Nacional de Obras Contra as Secas. A região vivencia constantes períodos de estiagens, em que a última seca fora considerada a pior dos últimos anos, com seu início em 2012 e atingindo seu colapso em 2014. Em 2017 o açude atingiu 2,19 do seu volume. O Boqueirão é responsável pelo abastecimento de água de importantes cidades do estado, a exemplo de Campina Grande, demonstrando a necessidade da utilização dos instrumentos de Gestão previstos na Política Nacional de Recursos Hídricos como forma de se buscar uma gestão hídrica eficiente e consciente. Nesse contexto, o estudo foi constituído com o objetivo de analisar a forma de implementação dos instrumentos de gestão previstos na Política Nacional de Recursos Hídricos (PNRH) no Açude Epitácio Pessoa. Para a composição da pesquisa foi adotada a técnica exploratória e descritiva para a busca e coleta de dados, realizando estudos bibliográficos e de caso, junto aos órgãos competentes e seus responsáveis, para que se pronunciassem sobre a forma de gerenciamento desses recursos hídricos. Assim, foram analisados aspectos sobre a escassez hídrica em âmbito mundial e nacional, seguindo pela análise da gestão dos recursos hídricos no estado da Paraíba, bem como suas características geográficas e a política e domínio dos seus recursos. A abordagem seguinte caracterizou o objeto de análise, o açude ¿O Boqueirão¿, e a sua estrutura institucional de gestão. Por fim, foi analisada a aplicação dos instrumentos de gestão hídrica no açude, buscando concluir se as medidas adotadas têm sido eficientes e eficazes. Logo, foi possível concluir que, embora teoricamente a aplicação dos instrumentos de gestão no açude Epitácio Pessoa esteja sendo feita de maneira correta, a necessidade de cumprir rigidamente as disposições legais faz com que a gestão compartilhada entre a ANA e a AESA seja conturbada, por vezes confusa e crie um ambiente de constante conflito de competência e excesso de burocracia. / The Epitácio Pessoa Dam, popularly known as "O Boqueirão", is located in the Paraíba State within the Paraíba River Hydrographic Basin, located in areas of the semi-arid Paraíba, where the lowest rainfall rates in Brazil are recorded. Its construction took place in the 50s, by the National Department of Works Against the Droughts. The region lives constant drought periods, in which the last drought was considered the worst in recent years, beginning in 2012 and reaching its collapse in 2014. In 2017 the dam reached 2.19 of its volume. Boqueirão is responsible for the water supply of important cities in the state, such as Campina Grande, demonstrating the need to use the management tools predicted in the National Water Resources Policy as a way to seek efficient and conscious water management. In this context, the study was constituted with the objective of analyzing the implementation of the management tools provided for in the National Water Resources Policy (PNRH) in Epitácio Pessoa dam. For the composition of the research, the exploratory and descriptive technique was used to search and collect data, carrying out bibliographic and case studies, together with the competent bodies and their officials, to express their opinion on the management of these water resources. Thus, aspects of water scarcity at a global and national level were analyzed, followed by the analysis of the water resources management in the state of Paraíba, as well as its geographic characteristics and the politics and domination of its resources. The following approach characterized the object of analysis, the "O Boqueirão" dam, and its institutional management structure. Finally, the application of the water management instruments in the dam was analyzed, seeking to conclude whether the measures adopted have been efficient and effective. Therefore, it was possible to conclude that, although the application of the management instruments in the Epitacio Pessoa Dam is being made correctly, the need to comply strictly with the legal provisions makes the shared management between ANA and EASA be troubled, sometimes confusing and create an environment of constant conflict of competence and excessive bureaucracy.
102

Geocronologia U-Pb em zircões do Complexo Carbonatítico Seis Lagos e depósito de Nb associado (Amazonas, Brasil)

Rossoni, Marco Bimkowski January 2016 (has links)
O depósito do Morro dos Seis Lagos (DMSL) é o maior depósito de Nb até hoje encontrado. A mineralização é laterítica, ocorrendo associada ao corpo principal do Complexo Carbonatítico Seis Lagos (CCSL). Este trabalho apresenta resultados da datação U-Pb (por MC-ICP-MS com LASER acoplado) de zircões de sete amostras abrangendo todos os tipos litológicos conhecidos no CCSL/DMSL: rocha encaixante (gnaisse), veio de feldspato na encaixante, siderita carbonatito (3 amostras) e crostas ferruginosas mineralizadas em Nb (2 amostras). Os zircões do gnaisse e do veio de feldspato forneceram idades de, respectivamente, 1.826 ± 9 Ma e 1.839 ± 29 Ma, as quais mostram que a litofácies Tarsira do Complexo Cauaburi (o embasamento do Domínio Imeri na Província Rio Negro) é de 16 Ma a 29 Ma mais antiga do que o anteriormente suposto. Os zircões de duas amostras de carbonatito forneceram idades de 1.837 ± 8 Ma e 1.841 ± 7 Ma, as mais antigas encontradas no Domínio Imeri no Brasil, interpretadas como relacionadas a rochas profundas, cujos zircões foram capturados pelo magma carbonatitico durante sua ascensão A idade de 1.818 ± 8 Ma obtida em zircões da crosta pisolítica indica que o Complexo Cauaburi foi uma importante fonte para os clastos presentes nesta crosta. A idade de 1.873 ± 70 em zircões da crosta fragmentada pode indicar que rochas mais antigas, de outra provincia, também participaram como fonte de clastos para a cobertura laterítica do CCSL. Os zircões de uma amostra de carbonatito da parte central do corpo forneceram duas idades: 1.841 ± 7 Ma e 1.457 ± 71 Ma. Esta última idade é interpretada como a idade máxima do CCSL. Análises por microssonda eletrônica indicam que os zircões mesoproterozoicos têm alguma afinidade com carbonatito. A possibilidade do CCSL ter uma idade mesoproterozoica é discutida à luz do atual conhecimento da evolução geológica da Província Rio Negro, concluindo-se por uma relação com a evolução do Cinturão K’Mudku. / The Morro dos Seis Lagos deposit (MSLD) is the world’s largest Nb-deposit. The lateritic mineralization occurs associated to the major body of the Seis Lagos Carbonatite Complex (SLCC). This paper presents results of U-Pb dating (by MC-ICP-MS, coupled to LASER) of zircons from seven samples that cover all of the known lithotypes in the SLCC/MSLD: host rock (gneiss), feldspar/kaolin intercalation in the host rock, siderite carbonatite (3 samples), and ferriferous Nb-mineralized crust (2 samples). Zircons from the gneiss and the feldspathic vein provided ages of 1.826 ± 9 Ma and 1.839 ± 29 Ma, respectively, which implies that the lithofacies Tarsira of the Cauaburi Complex (the basement of the Imeri Domain in the Rio Negro Province) is 16 Ma to 29 Ma older than previously supposed. Zircons from two carbonatite samples provided ages of 1.837 ± 8 Ma and 1.841 ± 7 Ma which are interpreted as ages of deeper host rocks whose zircons were extracted by the rising carbonatitic magma The age of 1.818 ± 8 Ma obtained in zircons from the pisolitic crust indicate the Cauaburi Complex as the main source of clasts for this crust. The age of 1.873 ± 70 in zircons from the fragmented crust may indicate that rocks from another province older than the Rio Negro Province also contributed as source of clasts to the SLCC lateritic cover. The zircons of a carbonatite sample from the central part of the carbonatite body yield two ages: 1.841 ± 7 Ma and 1.457 ± 71 Ma. The late age is interpreted as the maximum age of the SLCC. Analysis by electron microprobe reveals some evidences that the mid-Proterozoic zircons could be carbonatite zircons. The possible age of 1.457 Ma for the SLCC is discussed in view of the present knowledge on the geology of the Rio Negro Province; a relation with the evolution of the K'Mudku Belt is prognosticated.
103

Translating banlieue film : an integrated analysis of subtitled non-standard language

Silvester, Hannah January 2018 (has links)
This thesis examines the subtitling of films depicting the French banlieue into English. The banlieues are housing estates situated on the outskirts of large towns and cities, and are primarily home to the underprivileged, and immigrants to France or their descendants. The sociolect spoken in the banlieue differs from standard French in terms of grammar, lexicon and pronunciation. Three films released between 2000 and the present day are studied; La squale (Genestal, 2000), L'esquive (Kechiche, 2003) and Divines (Benyamina, 2016). A new integrated methodology is developed, which examines the films within their broader contexts of release, and in light of paratextual material contributing to the context of reception, and to the viewer's understanding of the topic at hand. Directors representing the banlieue on screen generally do so with a view to provoking thought or public discussion in relation to the banlieues. In addition to macro- and micro-contextual analysis of the films and subtitles, the work is underpinned by an examination of the subtitling situation, encompassing the views and experiences of subtitlers working on banlieue film, and technical analysis of the subtitles in terms of readability. Through interviews of professional subtitlers, and close technical analysis of the subtitles, this research is contextualised within the industry, and within current conventions and guidelines. Close analysis of subtitles and the translation solutions they present reveals that some of the socio-political messages presented in the films may not be evident to a non-French speaking viewer of the English-subtitled versions. Although the informal nature of many conversations featuring the langage de banlieue is sometimes clear in the subtitled version, the unique sociolect of the characters is not. In two of the case study films, a dialect-for-dialect approach was adopted, where African American vernacular English was used in the subtitles to demonstrate the use of non-standard language. However, it is argued that ultimately, this dialect-for-dialect approach, combined with cultural similarities between the French banlieue and American street culture, could lead the British Anglophone viewer to negotiate the banlieues and those who live there via their knowledge of American street culture. This could contribute to American cultural hegemony, and does not convey the specificity of France's banlieues as cultural melting pots.
104

Le Corps-frontière : figures de l'excès dans les fictions de Marie Darrieussecq, Virginie Despentes, Laurence Nobécourt et Marina de Van

Carlini Versini, Dominique January 2018 (has links)
No description available.
105

Measurement of the J/ψ elliptic flow in Pb-Pb collisions at √sNN=5.02TeV with the muon spectrometer of ALICE at the LHC / Mesure du flot elliptique du J/ψ dans les collisions Pb-Pb à avec le Spectromètre à Muons de l’expérience ALICE au LHC

Francisco, Audrey 24 September 2018 (has links)
Les conditions extrêmes de température et de densité d'énergie créées lors des collisions d'ions lourds ultra-relativistes au sein du Grand collisionneur de hadrons (LHC) fournissent une occasion unique d'étudier les propriétés de la matière. Une transition de phase de la matière hadronique vers un milieu déconfiné de quarks et de gluons (PQG) est prédite par la chromodynamique quantique et des efforts théoriques et expérimentaux considérables ont été investis pour étudier ses propriétés. Parmi les sondes éminentes du PQG, les quarks lourds jouent un rôle prépondérant car ils sont créés lors des processus durs initiaux, avant la formation du PQG, et leur nombre est conservé durant les phases partoniques et hadroniques de la collision. Les états liés de quarks lourds– quarkonium (charmonium pour cc et bottomonium pour bb), constituent des sondes remarquables du milieu. Les observations expérimentales de quarkonia aux énergies du LHC dans les collisions A-A sont reproduites au travers de deux mécanismes antagonistes : la suppression séquentielle, proposée très tôt comme signature du PQG, et la (re)génération de quarkonia par (re)combinaison de quarks déconfinés. Cependant des incertitudes importantes sont associées aux prédictions théoriques et de nombreuses inconnues demeurent. L'anisotropie azimuthale de l'espace des moments (désignée sous le terme de flot elliptique, v2) de la production de charmonium devrait permettre d'avoir une meilleure vue d'ensemble et de contraindre davantage les paramètres des modèles théoriques. Si les quarks charmés se (re)combinent en paires cc, les J/ψ produits devraient hériter de leur flot. Les études précédentes ont montré des premiers signes d'un v2positif du J/ψ dans les collisions Pb-Pb à √sNN=2.76TeV. Cette thèse porte sur la mesure de l'anisotropie azimuthale du J/ψ dans les collisions Pb-Pb à√sNN=5.02TeV où une (re)combinaison légèrement plus importante est prédite par rapport aux énergies inférieures et une augmentation statistique d'un facteur 3 a été enregistrée. L'étude du flot elliptique du J/ψ fournit des informations clés sur la magnitude et la dynamique des mécanismes de suppression et de (re)génération de charmonia. Par ailleurs elle offre un regard unique sur l'évolution et les interactions des quarks charmés au sein du milieu en expansion. / Extreme temperatures and energy densities produced in ultra-relativistic heavy-ion collisions at the Large Hadron Collider provide a unique opportunity to study the properties of matter. A phase transition of the hadronic matter to a deconfined medium of quarks and gluons, the Quark-Gluon Plasma (QGP), is predicted by Quantum Chromodynamics and considerable theoretical and experimental efforts have been invested to study its properties. Among the prominent probes of the QGP, heavy quarks play a crucial role since they are created in primary hard-scattering processes, before the QGP formation, and their number is conserved throughout the partonic and hadronic phases of the collision. Bound states of heavyquarks – quarkonium (charmonium for cc and bottomoniumbb) provide remarkable probes of the medium. At LHC energies, experimental observations of quarkonium in A-Acollisions are reproduced through two antagonist mechanisms: a sequential suppression of the quarkonium states, early suggested as a signature of the QGP, and quarkonium (re)generation by (re)combination of deconfined quarks. However, theoretical predictions carry large uncertainties and many unknows remain. The momentum space azimuthal anisotropy of charmonium production (referred as elliptic flow v2) should help to clarify the picture and to constrain the model parameters. If charm quarks (re)combine in the medium into cc pairs, the J/ψ originating from (re)combination should inherit their flow. Previous studies have shown first hints of a positive J/ψ v2 in Pb-Pb collisions at √sNN=2.76TeV. This thesis focuses on the measurement of J/ψ azimuthal anisotropy in Pb-Pb collisions at √sNN=5.02TeV where a slightly stronger (re)generation component is predicted with respect to lower collision energies, and a factor of 3more data were collected. The study of J/ψ v2 provides important information on the magnitude and dynamics of charmonium suppression and (re)generation mechanisms. In addition, it offers a unique insight on charm quark evolution and interactions in the expanding medium.
106

Investigating the lexicographical needs of Brazilian learners of English : a user study

Jardim, Carolina Reolon January 2018 (has links)
Dictionaries can be effective learning tools, capable of promoting learning autonomy to fill the gap left by an inefficient education for instance. The functional quality of these works is, however, tied to a good understanding of the profile of their intended users. In the field of lexicography, this understanding can be achieved by means of user-studies. Currently, most EFL dictionaries target a very generic profile - English learners - and neglect the fact that learners from different cultures and linguistic backgrounds may have different needs and preferences. This thesis presents and discusses the results of a lexicographic user-study conducted in Brazil with 61 English learners. The objective of this study was to investigate the profile of Brazilian learners of English as a target-group for EFL dictionaries. The study combined two methods of investigating dictionary use: written protocol and questionnaire. Through the written protocol, data about participants’ look-up strategies and samples of their performance in both receptive and productive EFL tasks were collected. The questionnaire gathered information about participants’ socio-cultural background and their consultation preferences. All data were analysed as follows: principles of Error Analysis were used to build a taxonomy capable of classifying participants’ errors resulting from reference source consultation (meaning, grammar, spelling or usage). The taxonomy was built based on the premise that it can be a valuable way of identifying the weakness of EFL learners in order to develop a dictionary to address their needs. With the results of this classification, it was possible to identify participants’ most frequent difficulties when performing EFL tasks. Once participants’ errors were located and classified, information about their look-up strategies was used to retrace the consulted reference source in order to find clues to explain why the consultation resulted in error. Finally, participants’ self-reported behaviour in the questionnaire was compared to their actual behaviour in the experiment. The results of this user-study suggest that both linguistic and socio-cultural background have an impact on learners’ expectations about dictionaries, their preferences, and the difficulties they experience while trying to access relevant linguistic information. The outcomes of this study shed light on the average profile of the Brazilian learner of English and it would be useful for other investigations towards the development of a lexicographic reference source to address the specific needs of this target group.
107

Serbian compliance patterns towards EU integration under the Progressive Party : an exercise in statecraft

Dragojlov, Aleksandra January 2018 (has links)
The overarching focus of this thesis is Serbian government strategies under the Serbian Progressive Party towards European integration based on a rationalist approach to Europe. Current research on Serbia assumes the rationalist approach whereby Serbian elites’ strategies towards EU integration are driven by the logic of consequences, in the calculation of benefits and losses resulting from EU membership. This study will take the analysis further by examining Serbian government strategies towards EU accession through the prism of rationalism as well as statecraft where the desire for power has been one of the main driving forces for the Progressives’ strategy to EU conditionality. The research will be a comparative case study using two distinct policy areas of Kosovo and media freedom in Serbia and argue that the Progressives have engaged in partial compliance with regard to Kosovo and fake compliance in the area of media freedom. Both cases have reputational costs of compliance but the differences in outcomes can be attributed to the extent of the EU’s competencies in each policy area and the visibility of Serbian compliance to conditionality. Media freedom, an internal issue, is a low visible area as media freedom legislation is namely in the hands of national governments, thereby limiting the EU’s capacity to regulate and enforce media freedom in some of its own member states as well applicants. Kosovo is a highly visible policy area as a consequence of the presence of external actors monitoring Serbian compliance, thereby increasing the EU’s capacity in this field and making Serbian compliance/non-compliance difficult to hide. Previous scholarship on EU integration in applicant states analyses the EU’s conditionality-driven approach which enforces compliance on acceding countries. However, the thesis seeks to contribute to the existing research by questioning the sustainability of such an approach and the EU’s legitimacy as a normative power seeking to export its values to accession countries. Serbia, is an example within a national context, that seeks to elucidate this argument especially in light of the EU’s exchange of regional stability (Kosovo) for external lenience on matters of democracy (media freedom).
108

Contributions du thermomètre Δ47 et du chronomètre U-Pb à l’étude de l’histoire diagénétique, thermique, et hydrogéologique des réservoirs carbonatés du Jurassique Moyen du bassin de Paris / Paired Δ47 geothermometry and U/Pb geochronometry to reconstruct the diagenetic, thermal and fluid-flow histories of carbonate rocks in sedimentary basins : case of the Paris basin

Mangenot, Xavier 18 December 2017 (has links)
Dans l’étude de la diagenèse des formations silico-clastiques ou carbonatées, il est souvent difficile de contraindre la température et l’âge des différents épisodes de cimentation ou de recristallisation. Le premier objectif de ce travail de thèse était de tester le potentiel de deux outils isotopiques récents (le géothermomètre des « clumpedisotopes » Δ47 et le géochronomètre U-Pb par analyse ponctuelle sur lame mince) dans le cadre de l’étude de la diagenèse des carbonates. Le deuxième objectif était de préciser l’histoire diagénétique, thermique, ethydrogéologique des réservoirs carbonatés du bassin de Paris. Pour atteindre ces deux objectifs, nous avons étudié des ciments de calcite et dolomite collectés dans les calcaires du Jurassique Moyen du dépocentre du bassin de Paris. La bonne caractérisation pétrographique et sédimentologique de ces échantillons, et le couplage entre les géothermomètres Δ47 et inclusions fluides, nous ont permis d’accéder à plusieurs informations de premier ordre. Premièrement, nous montrons que le Δ47 permet de reconstruire simultanément et précisément la température de formation des ciments diagénétiques dans la gamme 60-100°C (avec une précision de ~3-5°C) et la composition isotopique en oxygène des fluides (δ18Owater) à partir desquels ces ciments ont précipités (avec une précision de ~ 1‰). Deuxièmement, nous présentons une amélioration des connaissances de l’histoire thermique et des périodes de paléo-circulation des fluides à l’échelle régionale dans le bassin de Paris. Notamment, le croisement du géothermomètre Δ47 avec la méthode de datation U-Pb nous a permis pour la première fois de poser des contraintes thermo-chronologiques absolues sur l’ensemble des phases de circulations de fluides étudiées. Plus largement, ce couplage Δ47 /(U-Pb) inédit dévoile un champ d’application nouveau en thermo-chronologie de basse température (10-100°C). Nous anticipons que ce travail initie de nombreuses applications pour l’étude des histoires thermiques des bassins sédimentaires, via l’analyse de la diagenèse des carbonates / Diagenesis studies of both siliciclastic and carbonate rock units face the difficulty of constraining the temperature and age of the successive episodes of mineral crystallization. The first objective of this PhD work was to test the potential of two recent isotopic tools (the "clumped isotopes" Æ47 geothermometer and the laser ablation U-Pb geochronometer ) to integrate conventional carbonate diagenesis studies. The second objective was to reconstruct the diagenetic, thermal, and hydrogeological histories of the Middle Jurassic carbonate reservoirs of the Paris Basin. To achieve these goals, we studied calcite and dolomite cements mostly collected in the basin subsurface (exploration cores). The good petrographical and sedimentological characterization of the studied samples, together with the analysis of fluid inclusions and ?47 thermometry for determining the temperature and the chemical and isotopic compositions of the mineralizing fluids, allowed us to reach several first-order information. First, we show that Æ47 allows to simultaneously and precisely reconstruct the formation temperature of diagenetic cements in the range 60-100 ¡C (with an accuracy of ~ 3-5 ¡C) and the oxygen isotopic composition of the parent fluids (d18Owater) with a precision of ~ 1 ä. Secondly, this work improves our knowledge on the thermal history and past fluid-flows occurring at the basin scale. In particular, the coupling of the Æ47 thermometer with the U-Pb chronometer permitted for the first time to set absolute thermo-chronological constraints on every fluid-flow episodes investigated. More broadly, this unprecedented Æ47/(U-Pb) coupling reveals a new field of application in the low-temperature thermo-chronology field (10-100 ¡C). We anticipate that this pioneer thermo-chronological approach will induce many future applications in the study of sedimentary basins via carbonate diagenesis studies
109

Protein Bound 3,4-Dihydroxyphenylalanine as a Signal for Enhanced Antioxidant Defences

Nelson, Michelle Amy, n/a January 2008 (has links)
Protein-bound 3,4-dihydroxyphenylalanine (PB-DOPA), a long-lived, redox-active product of protein oxidation, is capable of functioning as both a pro- and anti-oxidant. A number of in vitro and in vivo studies have demonstrated a toxic, non-toxic or even beneficial effect of free DOPA, however little investigation has examined the physiological activity of PB-DOPA. Furthermore, as free DOPA is currently the major treatment available for Parkinson?s disease, most studies have focused on the effect of DOPA within neurological cells or tissues, although the presence of PB-DOPA in other locations, for example within atherosclerotic plaques, suggests that broader research is needed to fully understand the physiological effects of both free and PB-DOPA. The hypothesis presented in this thesis is that under physiological conditions, when little redox active transition metal is available, PB-DOPA can function as a redox signalling molecule, triggering an enhancement of cellular antioxidant defences, with a potentially specific role in the regulation of defences targeted against protein oxidation. Physiological levels of PB-DOPA are very low, however the level on individual proteins can change to a proportionally large degree during oxidative stress, an appropriate property for a signalling molecule. In addition, remarkably elevated levels occur in some pathologies, including atherosclerosis. As an initial and commonly formed product of protein oxidation, PB-DOPA is well placed for a signalling role, promoting a significant up-regulation of antioxidant defences in the early stages of oxidative stress, before extensive damage has occurred. As an initiator of antioxidant defences, PB-DOPA would be potentially useful as a therapeutic for the treatment of diseases involving oxidative stress or the accumulation of oxidative damage. The main objective of this thesis was, therefore, to examine the effect of PB-DOPA on the cellular antioxidant defence system using monocytic and macrophage-like cells, key cells involved in the formation of atherosclerotic plaques. The incorporation of free DOPA into protein during protein synthesis, a process previously shown to occur both in vitro and in vivo, was used to generate PB-DOPA. Neither free nor PB-DOPA were found to be toxic to monocytic or macrophage-like cells in culture, but rather were both capable of protecting these cells from oxidative stress. Free DOPA was shown to be capable of directly scavenging radicals, a process that was thought to be in part responsible for the protection induced during oxidative stress. The presence of free and PB-DOPA up-regulated the activity of catalase and NAD(P)H:quinone oxidoreductase, two enzymatic antioxidants, however the activity of superoxide dismutase and the concentration of oxidised and reduced glutathione were not affected. Whilst it was thought that PB-DOPA would have a specific effect on the activity of antioxidant defences targeted against protein oxidation, proteolysis and bulk chaperone activity were not affected by a combination of free and PB-DOPA. Oxidatively-induced protein aggregation, however, was inhibited by the presence of free and PB-DOPA, suggesting that a more specific chaperone regulation may be taking place. The regulation of gene and protein expression was thought to be one possible mechanism by which PB-DOPA could function as a signalling molecule. To test this hypothesis, the effect of free and PB-DOPA on transcription factor activation and protein expression were investigated. Free and PB-DOPA did not induce the expression or activation of Nrf2, AP-1 or NFJB, three transcription factors thought to be involved in the expressional regulation of genes involved in the antioxidant defence system. However, the expression of a number of proteins, including antioxidants, chaperones and proteins involved in cell cycle progression, were regulated in monocytic and macrophage-like cells following the administration of free DOPA under conditions that resulted in either a high or low level of PB-DOPA generation. The regulated proteins differed between the two conditions, suggesting that the level of PB-DOPA may be a key factor in determining the specific defences targeted. The results presented in this thesis support the hypothesis that PB-DOPA can function as a signalling molecule, triggering an enhancement of cellular antioxidant defences, with a specific role in the regulation of the chaperone system, a key defence targeted against protein oxidation. This thesis may provide the basis for the potential use of free or PB-DOPA as a therapeutic for diseases known to involve oxidative stress or oxidative damage, however more research will be required to determine if the effects demonstrated in this thesis are also capable of occurring in vivo.
110

Settling Particulates and Sediments in the Northern South China Sea: Study of Flux and Pb-210

Huang, Huei-chung 31 July 2007 (has links)
In this study, the sediment cores taken in the northern South China Sea (SCS) as well as the settling particulates collected from time-series sediment traps deployed in the same area have been analyzed for Pb-210 activities in order to estimate the sedimentation rate and mass flux from core data and to obtain temporal variations in mass flux and Pb-210 from the time-series sediment traps. The main purposes are to compare and to discuss the mass balance problem between the sediment trap and core results in terms of mass flux, Pb-210 activity and its fluxes. The time-averaged particulate fluxes measured from different depths at M3S and M1T sites in the northern SCS generally increase with depth, reflecting an increasing effect of the lateral transport. The upper and middle traps display a synchronous trend in mass flux variations. The mean particulate flux at S5 site near Luzon Strait is clearly higher than the two sites mentioned above probably because of the effect of topography and bottom current. Distributions of Pb-210 are influenced by particulate scavenging: the longer the settling particles stay in the water column the more the surrounding Pb-210 will be scavenged. The temporal variations of Pb-210 at M3S show a similar trend and an increase with depth. At M1T site, the temporal variations of Pb-210 show no clear trend due to insufficient samples. It has been commonly observed in the marginal sea that Pb-210 activity is inversely correlated with the associated mass flux, i.e. higher Pb-210 is associated with lower mass flux in terms of their temporal variations. This study is also in line with such observations. The mean water content of the core at I located near the shelf break in the northern SCS is about 28%, and its mean loss on ignition (L.O.I.) is 3.2%. These are similar to those observed previously in the northern SCS (water content: 25-37%; L.O.I.: 3%-8%). The sedimentation rate as determined from the excess Pb-210 profile at core I is 18cm/100yr which is at the lower end of the previous study (16-52 cm/100yr) (Wu, 2006). The sediment flux and sedimentation rate estimated from both the Pb-210 inventory (I) and the upper limit of sedimentation rate are identical, respectively, at 0.32 g/cm2/yr and 18cm/100yr. Thus the mixing effect could be neglected. The Pb-210 flux estimated from the deep sediment trap at 2163m (M3S, 77.4 dpm/m2/d) is much lower than that observed from the core sediment (F, 761.1 dpm/m2/d). Although the specific Pb-210 activity of the particles is much greater than that in the surface sediment, the particle flux is too small relative to the mass flux of the sediment, suggesting that additional sediment with Pb-210 has been transported laterally from elsewhere and deposited here. This results in a large imbalance between the sinking particulates and the underlying sediment in mass flux and Pb-210 flux.

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