This thesis attempts to contribute to the discussion over the problem of maritime piracy that poses a threat to maritime transport as well as international trade. The impact of maritime piracy was researched mainly in the context of Somali pirates. Currently the problem concerns other areas, which are the subject of my investigation. The thesis is focused on maritime piracy in the Gulf of Guinea and Southeast Asia, which are the current piracy hotspots. The main goal is to identify the implications of maritime piracy and analyze its impact on international trade in the given regions.

In the heart, the existence of an electrical memory was firstly reported by Rosenbaum et al. (1982), but Rios et al. (1975) and Garcia Moreira (1977) were those that firstly described the existence of contractile memories in the amphibian myocardium. These authors developed a mathematical model for representing such phenomenon. In the present study, we aimed to characterize two kinds of contractile memories occurring in the mammalian myocardium. One of them, depresses the tissue (the depressant memory, DM) and the other one acts by stimulating it (the excitatory memory, EM). The pivotal rationale guiding this work was: when the heart is challenged by changing the environment sources like nutrients, chemicals, temperature, etc., its behavior changes in order to optimize the energy expenditure associated with its contractility. This adaptation process allows to be reached a new state of dynamic equilibrium. In order to express such behavior, the tissue creates contractile memories for adjusting the amplitude of myocardial forces. This is provided by balancing the load of DM and EM available at each myocardial beat. The expression and accumulation of these memories were studied in the guinea pig atria submitted to the experimental protocols described previously by Seed & Walker (1988), Shimizu (2000), and Conde-Garcia (not published). The expression and accumulation of myocardial memories were described by employing two static descriptors, LODMmax and LOEMmax. They stand for the maximum load of depressant memory and the maximum load of excitatory memory, respectively. Furthermore, another pair of dynamic descriptors was also used to measure the maximum rate of erasing of the depressant memory (MREDM) and the other one to measure the maximum rate of erasing of the excitatory memory (MREEM). The static descriptors represent the transference of load of both memories but the dynamic descriptors were related to the rate of erasing of such memories. Our results brought us onto the following conclusions: 1. contractile memories are a phenomenon apart from the electrical memory because rising the external potassium from 2.7 to 7.0 mM did not modify (n n = 4) LODMmax that changed from 82,09 ± 1,58 to 81,56 ± 2,01% (p > 0,05), LOEMmax from 83,36 ± 0,56 to 90,12 ± 17,92% (p > 0,05), MREDM changed from -1,36 ± 0,67 to -1,13 ± 0,42gf/s (p > 0,05), and MREED from -2,09 ± 1,65 to -1,56 ± 1,41gf/s (p > 0,05). 2. However, the expression and accumulation of DM and EM are affected by the intracellular calcium transient. The increase of extracellular calcium from 1,37 to 5,47mM (n = 3) reduced LODMmax: from 87,56 ± 2,33 to 63,83 ± 3,78% (p < 0,05); LOEMmax from 84,36 ± 0,54 to 13,91 ± 0,11% (p < 0,05); MREDM from -2,58 ± 0,71 to -1,20 ± 0,37gf/s (p < 0,05) and MREEM from -0,90 ± 0,13 to -0,34 ± 0,05 gf/s (p < 0,05). Adding 5mM cafeine to the bath solution also reduced LODMmax from 79,88 ± 3,48 to 56,68 ± 6,62% (p < 0,05); LOEMmax from 77,14 ± 1,02 to 28,54 ± 2,11% (p < 0,05); MREDM from -1,78 ± 0,50 to -0,60 ± 0,10 gf/s (p < 0,05), and MREED from -1,74 ± 0,64 to -0,33 ± 0,14 gf/s (p < 0,05); 3. In the experimental condition employed in this work, a given beat receives both depressant and excitatory information built by the last ten beats. / A capacidade de o miocárdio memorizar foi estudada inicialmente por Rosenbaum (1982), que, entre outros, relataram uma memória elétrica no coração. Todavia, Rios e cols. (1975) e Moreira (1977) foram os primeiros a descrever a existência de memória contrátil no miocárdio de anfíbio. Eles propuseram um modelo matemático para representar esse fenômeno. A nossa proposta, contudo, visou caracterizar dois tipos de memórias contráteis. Uma delas inibe o inotropismo (memória depressora, MD) e a outra, o estimula (memória excitadora, ME). A hipótese central deste trabalho propõe que, quando o coração é desafiado por um novo ambiente (nutrientes, químicos, pH etc.), ele redefine sua atividade contrátil para que possa alcançar um novo estado de equilíbrio. Para expressar tal comportamento, o miocárdio cria memórias, visando ajustar a amplitude das forças geradas. Isto se dá por meio do balanço entre a carga de MD e de ME de cada batimento. Neste trabalho, a expressão e a acumulação destas memórias foram estudadas em átrio de cobaia, utilizando-se dois descritores para cada uma delas um estático, o IKMDmax e IKMEmax, que representam o incremento máximo de carga de MD e ME, respectivamente, e outro dinâmico VmedAMD e VmedAME - que está associado à velocidade de apagamento de cada memórias. As preparações foram ensaiadas com diferentes protocolos experimentais como os descritos por Seed & Walker (1988), Shimizu, et al. (2000) e Conde-Garcia (não publicado). Os resultados mostraram que a memória contrátil difere do fenômeno relativo à memória elétrica do miocárdio, porque, elevando-se o potássio externo de 2,7 para 7,0 mM, não houve variação significativa dos descritores, pois, para n = 3, o IKMDmax passou de 82,09 ± 1,58 para 81,56 ± 2,01% (p > 0,05), o IKMEmax passou de 83,36 ± 0,56 para 90,12 ± 17,92% (p > 0,05), a VmedAMD variou de -1,36 ± 0,67 para -1,13 ± 0,42gf/s (p > 0,05) e a VmedME foi alterada de -2,09 ± 1,65 para -1,56 ± 1,41gf/s (p > 0,05). A expressão e a acumulação das memórias são fenômenos que dependem do transiente intracelular de cálcio nas células miocárdicas. A elevação do cálcio extracelular de 1,37 para 5,47mM, para n = 3, alterou o IKMDmax: de 87,56 ± 2,33 para 63,83 ± 3,78% (p < 0,05); IKMEmax: 84,36 ± 0,54 para 13,91 ± 0,11% (p < 0,05); VmedAMD: -2,58 ± 0,71 para -1,20 ± 0,37gf/s (p < 0,05) e VmedME: -0,90 ± 0,13 para -0,34 ± 0,05 gf/s (p < 0,05). A adição de 5mM de cafeína à solução controle do banho fez o IKMDmax variar de 79,88 ± 3,48 para 56,68 ± 6,62% (p < 0,05); o IKMEmax de 77,14 ± 1,02 para 28,54 ± 2,11% (p < 0,05); a VmedAMD de -1,78 ± 0,50 para -0,60 ± 0,10 gf/s (p < 0,05) e a VmedME -1,74 ± 0,64 para -0,33 ± 0,14 gf/s (p < 0,05). Nas condições experimentais deste estudo, uma dada contração recebe informações depressoras e excitadoras que foram geradas pelos últimos dez batimentos.

Morphogenesis is the fundamental and remarkable biological process that produces elaborate and diverse tissues and organs from simple groups of cells, which can happen on timescales as short as minutes or as long as days. One of the biggest challenges in understanding morphogenesis is the gap between our knowledge of the molecular-scale activities of genes and proteins, and the large-scale behaviors of cells and tissues. To fill this gap, a complete understanding of both biochemical and mechanical factors involved in morphogenesis is needed. Morphogenesis is naturally a mechanical process in which tissues are physically sculpted by mechanical stress, strain, and movements of cells that are induced by these genetic and molecular programs. However, many of the mechanical factors involved in morphogenesis remain poorly understood partially due to the strong coupling of mechanical factors and biological factors, the active responses of living tissues to the environment, and the lack of experimental methods to study the mechanics of tissues in vivo. Epithelial tissues play crucial roles in shaping early embryos and are widely spread in mature animals to serve as boundaries and barriers. They are robust tissues that not only support the structure of embryos and organs, but also actively change shape and structure, displaying a fluid behavior during morphogenesis. Contractile tension and cell-cell adhesion are thought to be the main mechanical factors involved in epithelial tissue morphogenesis, but how the balance between these two determines epithelial tissue mechanics remains unclear. To build a fundamental understanding of the mechanical mechanisms underlying epithelial tissue morphogenesis, this dissertation studies the germband epithelial tissue in the early Drosophila melanogaster embryo and addresses two important open questions in the field of mechanics in morphogenesis: (1) what mechanical factors are involved in the morphogenesis of epithelial tissues; (2) how does a cell control these factors to tune tissue mechanical behaviors. In this dissertation, we developed a systematic, quantitative, in vivo experimental approach to explore mechanics of epithelial tissue morphogenesis in the Drosophila embryo by integrating molecular genetics approaches, live confocal fluorescence imaging, and quantitative image analysis. Combining our experimental studies in the Drosophila embryo with our collaborators’ theoretical modeling approaches, we showed that the shapes and alignment of cells within tissues can help us understand and predict epithelial tissue mechanical behaviors, such as tissue fluidity, during morphogenesis and how defects in these processes can result in abnormalities in embryo shape. We also observed that the Drosophila germband tissue transitions from more solid-like to more fluid-like behavior to help accommodate dramatic tissue flows during convergent extension, which indicates that the mechanical properties of developing tissues might be tuned during morphogenetic events. To elucidate molecular mechanisms underlying how tissue mechanical properties may be regulated during morphogenesis, this dissertation explores the role of cell-cell adhesion in controlling epithelial tissue mechanics. By systematically modulating cell-cell adhesion levels in the Drosophila germband tissue and combining live imaging and quantitative image analysis, we studied the effects of cell-cell adhesion levels on cellular and tissue behaviors. We found biphasic dependencies of cell rearrangements, cell shape, and tissue fluidity on cell-cell adhesion levels, which are surprisingly linked to each other by cell patterns in the tissue. In particular, tissues comprising cells with either lower or higher cell-cell adhesion levels tend to rearrange faster and show cell patterns indicating more fluid-like tissue behaviors. Further studies suggested that cell-cell adhesion works with cytoskeletal molecules to achieve these effects. The experimental approaches developed for exploring mechanics in 2-D in the Drosophila germband epithelial tissue are expanded upon in order to investigate germband tissue mechanics in 3-D. These approaches are also used to study mechanics in the inner ear round window membrane of the guinea pig for clinical application. This dissertation advances our understanding of mechanics of epithelial tissue morphogenesis in vivo and provides a practical, quantitative, and appealing platform for exploring mechanics in living tissues during morphogenesis. This helps fill the gap in our knowledge of molecular-scale activities and tissue-level behaviors, provides insight into building tissues with precise shapes and structures in the lab, and sheds light on human diseases associated with improper regulation of tissue mechanics such as birth defects, aberrant wound healing, and cancer metastasis.

Actuellement estimés à environ 8 millions d'individus, les Peuls constituent un ensemble de populations réparties sur une vingtaine de pays de la zone sub-saharienne. À partir d'une origine qu'ils affirment commune et qui, selon l'hypothèse la plus couramment admise, se situerait en Égypte, ils auraient connu de multiples mouvements migratoires, mais en conservant dans tous les cas le souci d'organiser leur vie sociale autour de l'élevage bovin. Mieux qu'un symbole, la vache leur apparaît comme l'animal fondateur de leur personnalité ethnique. On remarque cependant des différences notables selon qu'ils sont nomades, sédentaires ou semi-nomades. Les dispersions connues au cours des siècles, pour des raisons diverses (entre autres : économiques, politiques, climatiques), ont eu pour conséquences des écarts culturels parfois profonds. En procédant à une comparaison des sédentarisés en Guinée, sur les plateaux du Fuuta-Jaloo, et des nomades et semi-nomades du Tchad, il s'agit de mettre en relief certaines de ces différences et, par contraste, de discerner les points communs qui pourraient révéler un patrimoine unique. Dans le cas particulier des sédentaires devenus citadins et ayant perdu pour cette raison toute implication dans une activité pastorale, la vache reste au centre de leur imaginaire. Elle persiste à influencer leurs discours par de nombreuses références dans le jeu des métaphores, dans les formules de politesse, dans la valorisation des conduites, etc. On le vérifie autant par l'observation de la vie quotidienne que par les initiatives de certains intellectuels Peuls qui ont créé des associations pour promouvoir ce patrimoine à la fois dans leur pays de résidence et à l'international, comme par la création de sites Web. Ils ont même tendance à gommer ou atténuer fortement les différences apparues historiquement entre les groupes, voire à minorer des métissages survenus de génération en génération, pour proposer comme une sorte de standard uniforme. Dès lors, ils renvoient eux aussi à un lointain passé, mais parfois avec des partis-pris idéologiques qui participent d'un militantisme politique ou religieux, l'intention avouée ou non étant de définir une « nation peule » qui, bien que fragmentée dans plusieurs États, gagnerait à prendre conscience de sa singularité en Afrique. Au fil de l'enquête de terrain, l'attention est portée autant sur des données événementielles caractéristiques, comme celles qui scandent les existences individuelles et collectives (naissance, mariage, décès), que sur des données organisationnelles (exercice de l'autorité, coopération des genres au sein de la famille et du clan, classes d'âge, interactions économiques, gestion du bétail, conception de l'espace et du temps, prédéterminations religieuses, etc.).Gagnent également à être précisées les influences exercées sur les Peuls par les autres populations côtoyés au gré de leurs déplacements ou de leur fixation sur un territoire, influences provoquant l'acquisition durable de manières ou de techniques. Nonobstant les emprunts linguistiques, elles sont flagrantes dans la construction de l'habitat, temporaire ou définitif, et dans le choix de l'habillement. Jusqu'à une époque récente, les peuls ne sont pas réputés pour avoir un artisanat propre. Les choix qu'ils font pour modifier leurs rapports aux objets fabriqués en dehors d'eux répondent à des besoins dont il s'agira d'exposer la nature. Par exemple, de nos jours, l'emploi du téléphone portable accélère considérablement les prises de décision lors des transhumances. Au final, sachant l'omniprésence de la vache dans la culture peule, quelles que soient l'évolution du contexte matériel et social, il conviendra de clarifier la fonction structurante qu'elle exerce donc à la fois sur la plupart des pratiques et sur les représentations symboliques. Elle polarise en quelque sorte la production culturelle revendiquée comme l'héritage d'une tradition multiséculaire. […] / Currently estimated at about 8 million, the Fulani people make up a population spread over twenty-odd countries in sub-Saharan Africa. Sharing a commonly claimed origin said to be situated in Egypt, they are to have experienced several multiple migrations, while maintaining in all cases the desire to organize their social life around bovine cattle-breading. More than just a symbol, the cow is seen as the founding pillar of their ethnic character. There are, however, noticeable differences depending on whether the people are nomad, sedentary or semi-sedentary. Well-documented population dispersions throughout the centuries for various reasons, (amongst others: economic, political, climatic...), have led to sometimes profound cultural differences.The objective of making a comparison of the sedentary populations of the Fuuta-Jaloo Plateau of Guinea and the nomads and semi-nomads of Chad is to highlight some of these differences and, on the contrary, to identify the common denominators which may be considered to reveal a unique heritage.Concerning the sedentary populations which have become urban dwellers and have, for this reason, lost all involvement in pastoral activity, the cow remains central in their psyche. It continues to have an influence on their speech with multiple references to be found in metaphors, expressions of common civilities, the evaluation of common codes of behavior, etc. This can be seen as much by observing daily life as through the initiatives ta ken by certain Fulani intellectuals who have created associations to promote this heritage on both a national and international scale via, for example, the creation of websites. There is even a tendency to erase or greatly reduce historical differences which have come to light between the groups, or to underestimate mixed-race populations throughout generations in order to offer a uniform standard. Accordingly, they also refer to a distant past, but sometimes with ideological biases which contribute to political or religious activism, the intention of which, whether admitted or not, being to define a « Fulani nation» which, although fragmented over several States, would gain from a recognition of its uniqueness in Africa.Throughout the fieldwork study, the focus is as much on data from characteristic events making up individual and collective life, (birth, marriage, death), as on the organization of everyday life, (exercise of authority, family and clan unity and cooperation, age-groups, economic interaction, livestock management, the concept of space and time, religious and other predeterminations, etc.).Also worth noting are the influences of other populations on the Fulani people during their migrations or attachments to a territory, influences leading to the lasting acquisition of living manners and techniques.Notwithstanding linguistic borrowings, the influences are obvious where temporary or permanent dwelling construction and choice of clothing are concerned. Until recently, the Fulani people were not renowned for having their own craft. The choices they make to modify their relationship with objects constructed by others being directly determined by the needs presented to them by nature. For example, nowadays, the mobile phone has considerably accelerated decision-making during transhumance.In conclusion, given the omnipresence of the cow in the Fulani culture, whatever the social and cultural evolution may be, it is worth clarifying the structural role that the cow plays on the majority of practices and symbolic representations. It somehow polarizes the cultural production claimed as the heritage of a multisecular tradition. Hence the concern expressed from the very first interviews of the field survey of a possible risk of loss or significant reduction of bovine cattle-breeding. They feel they will lose the founding stone of their identity.

John Hawkins' three voyages to Guinea were anomalous in respect of the first eight decades of English commercial voyaging to Guinea (1550s-1630s), in that they were slaving voyages and hence proceeded to America. His third voyage of 1567-1569 was the most ambitious and, partly because it ended in disaster, the best recorded. This edition analyses the Guinea section of the voyage by drawing on English, Portuguese and Spanish sources. Two notable features are an attack on a Portuguese shipping base in River Cacheu, an episode concealed in the account published at the time, and the mercenary assistance lent to one side in an African civil war in Sierra Leone. The evidence for each Guinea episode, much of it previously unpublished, is presented with a commentary.

Introduction: Guinea worm disease (GWD) is a painful, disabling disease caused by the parasite dracunculus medinensis. The implementation of the global GWD eradication campaign resulted in a decrease of global burden of disease and several countries have been proclaimed free of the disease. Though, Ethiopia has implemented the GWD eradication programme since 1992 the disease remains endemic in the Gambella region. Purpose of the study: The purpose of this study was to explore the perceptions and experiences of the community of Gambella region on Guinea worm disease (GWD) eradication interventions. Methodology: A qualitative study paradigm with a phenomenological research design was employed to collect data using focus group discussions, in-depth individual interviews, document reviews, and observations. The study participants were determined by purposive sampling. Qualitative data analysis involved transcription, data entry, and management of verbal information followed by coding, categorizing into themes. Interpretation of the data was done using triangulation methodology with appropriate mechanisms for validity and trustworthiness. Result: The study found that there are gaps in the perceptions and understanding of the community and programme implementers about the achievement and application of the various interventions on the eradication of Guinea worm disease. Health education programme was not fine-tuned to the eradication of GWD by community participation. Community perception was not at the required level for the eradication of GWD due to the low success of the educational intervention. Conclusion: continuous health education targeting the community with clear objectives of helping to eradicate GWD was found to be limited in its coverage. In addition, provision of water filters necessary for GWD eradication was inadequate. Moreover, the community did not have clear understanding of the causes of GWD and its eradication strategy. It is hoped that the findings of this study would contribute significantly to the GWEP in Gambella region, as well as elsewhere where GWD may be endemic / Health Studies / M.A. (Public Health)

Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15–20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling.

This paper aims to determine whether chronic vagus nerve stimulation (VNS) mitigates myocardial infarction (MI)-induced remodeling of the intrinsic cardiac nervous system (ICNS), along with the cardiac tissue it regulates. Guinea pigs underwent VNS implantation on the right cervical vagus. Two weeks later, MI was produced by ligating the ventral descending coronary artery. VNS stimulation started 7 days post-MI (20 Hz, 0.9 ± 0.2 mA, 14 s on, 48 s off; VNS-MI, n = 7) and was compared with time-matched MI animals with sham VNS (MI n = 7) vs. untreated controls (n = 8). Echocardiograms were performed before and at 90 days post-MI. At termination, IC neuronal intracellular voltage recordings were obtained from whole-mount neuronal plexuses. MI increased left ventricular end systolic volume (LVESV) 30% (P = 0.027) and reduced LV ejection fraction (LVEF) 6.5% (P < 0.001) at 90 days post-MI compared with baseline. In the VNS-MI group, LVESV and LVEF did not differ from baseline. IC neurons showed depolarization of resting membrane potentials and increased input resistance in MI compared with VNS-MI and sham controls (P < 0.05). Neuronal excitability and sensitivity to norepinephrine increased in MI and VNS-MI groups compared with controls (P < 0.05). Synaptic efficacy, as determined by evoked responses to stimulating input axons, was reduced in VNS-MI compared with MI or controls (P < 0.05). VNS induced changes in myocytes, consistent with enhanced glycogenolysis, and blunted the MI-induced increase in the proapoptotic Bcl-2-associated X protein (P < 0.05). VNS mitigates MI-induced remodeling of the ICNS, correspondingly preserving ventricular function via both neural and cardiomyocyte-dependent actions.

«Les deux poumons d'un même corps» est une métaphore régulièrement usitée pour désigner les États du Mali et de Guinée et signifier le caractère arbitraire et absurde de leur séparation. Leur frontière commune est une ligne de 858 kilomètres, héritée de la limite administrative entre deux colonies de l'Afrique occidentale française. Jamais démarquée ni véritablement matérialisée, elle est issue du découpage territorial de l'Afrique occidentale française qui avait comme objectif simple de constituer des entités spatiales gérables et non de futurs États. L'objectif de cette thèse a été de considérer la frontière entre Guinée et Mali (ancien Soudan français) dans sa globalité, à partir de la conquête de cet espace, amorcée par les Français en 1878, jusqu'en 1956 et la mise en place de territoires autonomes au sein de l'AOF. Il était d'écrire son histoire, celle de sa construction puis de sa gestion par les Français mais surtout celle de son appropriation par les groupes sociaux qui habitent les espaces de la frontière. Analyser les pratiques trans-territoriales des populations, les formes d' instrumentalisation du cadre spatial imposé permet de saisir son historicité, d'effacer progressivement le caractère fantomatique de son tracé et d'envisager les processus de territorialisation par le bas qui ont contribué à faire émerger des identités nouvelles et à enraciner la frontière à la veille des bouleversements des indépendances. / "The two lungs of one and the same body" is a metaphor commonly used to refer to the states of Mali and Guinea, indicating the absurd and arbitrary nature of their separation. Their common border is a 858-kilometer long line, inherited from the administrative boundary between two colonies of French West Africa. Though never clearly demarcated nor actually materialized, it stems from the territorial division of French West Africa, the purpose of which was simply to create manageable geographical units, not future states. This thesis proposes to consider the border between Mali and Guinea (former French Sudan) in its entirety, from the territorial conquest initiated by the French in 1878, up to 1956 with the establishment of autonomous territories within the AOF (French West Africa). It proposes to write its history: its construction and then administration by the French but, above all, the story of its appropriation by the communities which live in the border territories. Analysing the populations' trans-territorial habits and the forms of exploitation of the imposed spatial framework enables us to grasp its historicity, to gradually erase the phantom nature of this line and imagine the processes of spatial appropriation from the bottom up and how this helped generate new identities and caused the border to take root on the eve of the upheavals of independence.

No description available.