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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.
221

Re-visiting history, re-negotiating identity in two black British fictions of the 21st Century: Caryl Phillips’s A distant shore (2003) and Buchi Emecheta’s The new tribe (2000)

Moudouma Moudouma, Sydoine 03 1900 (has links)
Thesis (MA (English Literature))--University of Stellenbosch, 2009. / Notions of home, belonging, and identity haunt the creative minds of fiction writers belonging to and imagining the African diaspora. Detailing the ways in which two diasporic authors “re-visit history” and “re-negotiate identity”, this thesis grapples with the complexity of these notions and explores the boundaries of displacement and the search for new home-spaces. Finally, it engages with the ways in which both authors produce “new tribes” beyond the bounds of national or racial imaginaries. Following the “introduction”, the second chapter titled “River Crossing” offers a reading of Caryl Phillips’s A Distant Shore, which features a black African man fleeing his home-country in search of asylum in England. Here, I explore Phillips’s representation of the “postcolonial passage” to the north, and of the “shock of arrival” in England. I then analyse the ways in which the novel enacts a process of “messing with national identity”. While retracing the history of post-Windrush migration to England in order to engage contemporary immigration, A Distant Shore, I argue, also re-visits the trans-Atlantic slave trade. In the final section, I discuss “the economy of asylum” as I explore the fates of the novel’s two central characters: the African asylum-seeker and the outcast white English woman. My reading aims to advance two points made by the novel. Firstly, that individuals are not contained by the nations and cultures they belong to; rather, they are owned by the circumstances that determine the conditions of their displacement. Phillips strives to tell us that individuals remain the sites at which exclusionary discourses and theories about race, belonging and identity are re-elaborated. Secondly, I argue that no matter the effort exerted in trying to forget traumatic pasts in order to re-negotiate identity elsewhere, individuals remain prisoners of the chronotopes they have inhabited at the various stages of their passages. The third chapter focuses on Buchi Emecheta’s The New Tribe. Titled “Returning Home?”, it explores the implications of Emecheta’s reversal of the trajectory of displacement from diasporic locations to Africa. The New Tribe allows for the possibility of re-imagining the Middle Passage and re-figuring the controversial notion of the return to roots. In the novel, a young black British man embarks on a journey to Africa in search of a mythic lost kingdom. While not enabling him to return to roots, this journey eventually encourages him to come to terms with his diasporic identity. Continuing to grapple with notions of “home”, now through the trope of family and by engaging the “rhetoric of return”, I explore how Emecheta re-visits the past in order to produce new identities in the present. Emecheta’s writing reveals in particular the gendered consequences of the “rhetoric of return”. Narratives of return to Africa, the novel suggests, revisit colonial fantasies and foster patriarchal gender bias. The text juxtaposes such metaphors against the lived experience of black women in order to demythologise the return to Africa and to redirect diasporic subjects to the diasporic locations that constitute genuine sites for re-negotiating identity.
222

A comparison of coronary heart disease risk factor prevalence among offshore and onshore workers in the petroleum industry in Nigeria

Iwot, Isang A. 12 1900 (has links)
Thesis (MFamMed)--Stellenbosch University, 2015. / Background: Coronary heart disease is a global public health problem. Formerly considered rare in sub-Saharan Africa, evidence has shown that urbanization and the adoption of more affluent and sedentary lifestyle in subpopulations of this region, may result in increased prevalence. One such subpopulation is workers in the Nigerian petroleum industry and this study examines their risk factors for coronary heart disease. In addition the study compares the risk profile of onshore and offshore workers. Method: This is a descriptive cross sectional study undertaken to determine the level of risk factors for the development of cardiovascular disease in two groups of male workers of the petroleum industry in Nigeria; the onshore and the offshore workers. Four hundred workers were randomnly selected and invited to participate, with a desired sample size of 234. The data was collected by using an electronic questionnaire to explore life style factors like exercise, diet, and smoking that predispose to this disease. Anthropometric indices included body mass index, waist circumference and waist to hip ratio. Biochemical tests included lipid profile and fasting blood glucose. Systolic and diastolic blood pressure was also recorded. The prevalence of known hypertension and diabetes as well as the metabolic syndrome were determined. The questionnaire data was analysed and compared with the chi-square test using the software, Epi-info 2008 Windows Version 3.5.1 and the means of the continuous variables were determined and compared using analysis of variance (ANOVA). Results: 121 onshore and 110 offshore workers participated. Overall the cardiovascular risk profile of onshore versus offshore workers in the oil industry was worse. Onshore workers had increased waist circumference,; though there was no significant difference in the Waist-Hip Ratio, increased rates of metabolic syndrome, diabetes and hypertension and were less physically active. Dietary differences were less marked, but more beef and chicken were consumed by onshore while more fish was consumed by offshore workers. Conversely the offshore workers had a higher BMI and lower levels of protective HDL. Overall, in this population, the BMI and the umber of diabetics were higher and the HDL lower than the country figures. Conclusion The obesity profile of the two groups was comparable to that of the Western nations and could become worse. This also reflects the fact that within Nigeria there are sub-populations with cardio-metabolic profiles that depart significantly from the national average. This is most probably due to dietary factors and poor exercise habits and calls for intervention through health promotional activities / AFRIKAANSE OPSOMMING: Nie beskikbaar
223

Amélioration de la sélectivité des protections électriques des navires lors de l'alimentation à quai - Augmentation du courant de court-circuit / Improved the electrical protections selectivity on vessel’s grid during the shore supplying - Increase of short-circuit current

Ion, Maricica-Mirela 14 January 2015 (has links)
Ce travail est relatif à l’augmentation du courant de court-circuit du réseau électriqueportuaire alimentant le navire. Ceci passe par une modélisation des réseaux des charges, dutransformateur et enfin convertisseurs concernés. Munis de cette compréhension du système,diverses solutions à base d’électronique de puissance ou d’éléments passifs ont étéinvestiguées, simulées et évaluées à l’aune des performances exigées. Pour l’augmentation ducourant de court-circuit, un transformateur spécialement créé pour cette application à deuxenroulements primaires est proposé. L’esprit de la solution est de modifier la configuration dutransformateur au moment de la détection du court-circuit en modifiant son rapport detransformation. Un banc de test temps réel hybride a été architecturé afin de tester cettesolution. Les essais sur le banc de test ont permis d’obtenir des résultats satisfaisants etencourageants qui corroborent la théorie. Pour finir des études complémentaires, sousdifférents scenarii, ont été menées en simulation hors ligne. / This work is about the short-circuit current increase, inside the harbor’s electrical networkthat supplies the electrical grid of each vessel docked in port. We analyze the system’srequirements, the load demands, the transformer and finally the modeling of the convertersinvolved. Armed with this understanding of the system, various solutions like powerelectronics devices or passive equipments were investigated, simulated and evaluated in termsof performance requirements. To increase the short-circuit current, we provide a noveltransformer with two primary windings. The purpose of this solution is to change theconfiguration of the transformer when the short circuit is detected by changing thetransformation ratio. A real-time hybrid test bench has been build in order to test the solution.The real-time tests have yielded good and encouraging results, supporting the theory. Finally,further studies under various scenarios were conducted in offline simulations.
224

Tax Avoidance: Critical Analysis of Current Regulations and Proposals for a Future Reform / La Elusión Tributaria: Análisis Crítico de la Actual Normatividad y Propuestas para una Futura Reforma

Echaiz Moreno, Daniel, Echaiz Moreno, Sandra 10 April 2018 (has links)
This paper describes and analyzes the configuration, the normative regulation and assumptions of tax avoidance and its differentiation from tax evasion, current regulations on matters related to tax avoidance, disputes relating to this figure due supported, the impact of international tax avoidance through tax havens figure, the way our country aims to combat this figure and finally propose suggestions for improving the anti-elusive regulations in order not to infringe against the taxpayer and any proper legal regulation. / En el presente ensayo se exponen y analizan la configuración, la regulación normativa y los supuestos de la elusión tributaria, así como su diferenciación con la evasión tributaria, la normatividad actual sobre materias vinculadas a la elusión tributaria, las controversias en relación a esta figura debidamente sustentadas, el impacto de la elusión tributaria a nivel internacional a través de la figura de los paraísos fiscales, la manera cómo nuestro país pretende combatir esta figura y, finalmente, planteamos propuestas de mejora a la normatividad anti-elusiva a fin que no se atente contra el contribuyente y exista una adecuada regulación jurídica.
225

\"Morfodinâmica de um segmento da praia da Ilha Comprida, litoral sul do Estado de São Paulo\" / Morphodynamic of Ilha Comprida beach segment, southern coast of the state of São Paulo

Mainara da Rocha Karniol Marquez 25 June 2007 (has links)
A dinâmica de praia constitui conhecimento elementar em obras de engenharia e na compreensão da evolução costeira ao longo do Quaternário recente. Buscou-se avaliar a variação temporal de curto período da morfologia e do volume de sedimento em um segmento na porção sul da praia da Ilha Comprida, litoral sul de São Paulo. Os resultados permitiram algumas interpretações, tanto em escala diária, como sazonal. As morfologias e os volumes do trecho estudado apresentaram maior similaridade entre as campanhas de maio de 2005 e janeiro de 2006, com estágio morfodinâmico de praia dissipativa, e entre agosto e novembro de 2005, com estágio de praia intermediária do tipo banco e calha. As ondas de sul com alturas de até 1 m e período médio entre 7 e 8 s atuaram no processo de engordamento da praia emersa, enquanto que as ondas desta mesma direção com alturas a partir de 1,5 m e período médio entre 8 e 10 s exerceram papel erosivo. De forma inversa, as ondas de leste com até 1 m de altura e período médio entre 6 e 8 s exerceram papel erosivo e com até 1,5 m e período médio entre 6 e 7 s, papel deposicional. / The knowledge of beach dynamics is fundamental in any coastal engineering projects as well as in the coastal evolution comprehension during the Late Quaternary. The aim of this study is to evaluate the short-term variations in morphology and sediment volume in a beach segment located in the southern portion of the Ilha Comprida, southern coast of the state of São Paulo, Brazil. The results allowed us to get important conclusions on daily and seasonal variations in beach morphology and behaviour. The morphology and volume data show similarity between may/2005 and jan/2006, with dissipative morphodynamic state characteristics, as well as between aug/2005 and nov/2005, characterized by an intermediate morphodynamic state. Southerly waves reaching 1m high and mean period between 7 and 8 s acts on the emerged part of the segment in a depositional way as well as southerly waves higher than 1,5 m and period between 8 and 10 s cause erosion in the same part of the beach profile. Easterly waves act in an opposite way, with lower heights causing erosion and higher causing deposition.
226

Ictiofauna do arquipélago de currais (Paraná - Brasil): complexidade estrutural dos costões rochosos e análise comparativa com um módulo recifal artificial.

Pinheiro, Pedro Carlos 07 July 2005 (has links)
Made available in DSpace on 2016-06-02T19:30:20Z (GMT). No. of bitstreams: 1 Tese PCP.pdf: 1520056 bytes, checksum: 159ec0fceaa491f7134dedfa0a07f099 (MD5) Previous issue date: 2005-07-07 / Universidade Federal de Sao Carlos / With the purpose of analyzing the ictiofauna of the natural environment of the Archipelago of Currais, located in the coast paranaense, and of an artificial reef installed in the proximities of the islands, the different studies were developed presented in the form of four chapters. The chapter I had as objective describes the space variation in the distribution and abundance of fish among four zones geomorphologics of the rocky islands of the archipelago and in the artificial module. The most abundant families were Pomacentridae, Labridae, Scaridae, Sparidae and Labrisomidae. The similarity analysis between the abundance and the areas showed that were not significant the differences for the slabs and shelf and the module recifal. The depth and exhibition degree to the agitated sea were the variables responsible physics for the heterogeneity of the abundances of the species in the areas of the outlying shore, slabs and shelf, windward rocky and module recifal. The differences in equitability terms and wealth of species can be due to the same variables. The inverse analysis showed that were few characteristic species in each grouping, therefore the differences among the areas seem to contemplate to the dominance of certain species. The categories dominant trophics were planktophagous and herbivores, which were significantly different among the areas. In the most shallow areas (slabs and shelf) and with high exhibition to the conditions of the sea (windward barrier reef) the herbivores and omnivorous prevailed, while in the deep ones (module recifal, windward rocky and sharp crags) the most abundant were the planktophagous. The carnivores showed significant differences among the protected areas (slabs and shelf). In the chapter II the variation nictemeral of the three rocky islands was just approached of the archipelago. The quali-quantitative results showed the distribution width and partition of niches among the species. The significant differences observed among the samplings of the day and night were evident due to the largest number of species captured during the night, moment of the cycle in that appeared represented all of the species found in the work. In the samplings of the day, they were significantly more abundant the species Anisotremus surinamensis, A. virginicus, Holocentrus ascensionis and Stegastes fuscus, while the night ones were characterized by the presence of species active predadors as Serranus flaviventris, Lutjanus analis, Cynoscion jamaicensis, Haemulon steindachneri, Abudefduf saxatilis, Diplodus argenteus, Mycteroperca bonaci and Epinephelus adscensionis. The species that allowed to differentiate the habitats of the day and night were practically the same ones, what demonstrated the great space heterogeneity that it presents the ictiofauna associated to the environments of the archipelago. The chapter III treated of the analysis trophic of the sparid Archosargus rhomboidalis relating with the aspects of the habitat use and predation in one of the islands of the archipelago (Grapirá) and the module recifal. The variation source observed among the two areas sampling presented significant differences among the times of the year. In the Isla Grapirá the most important preys in the autumn were the ascids and the amphipods, while in the winter and spring they were the amphipods. In the area of the artificial reefs, macroalgae and algae were more important in the summer, algae and hydrozoans in the autumn, algae and briozoans in the winter, and copepods harpacticoids and amphipods gammarids in the spring. A. rhomboidalis can be considered a species generalist euriphagic that feeds of a wide spectrum of preys. In the chapter IV the recruitment in the module recifal was analyzed by the categorization of the lengths of the most abundant species. The ictiofauna was analyzed along the temporary gradient with the objective of evaluating the efficiency of the attractiveness or of the productivity of the recruitment of fish. The results indicated that there were not significant differences in the qualitative and quantitative contribution of individual subadults or juvenile late for long periods in the time in the module recifal. The structure seems to work as atrator and concentrator of adult fish coming from close rocky bottoms. The factors that could determine the character attractive-concentrador for adult individuals it was the structural drawing and the geographical location where the module recifal was implanted. The originating from larval flow the masses of water of the Continental Platform and of the Bay of Paranaguá seemingly doesn't favor the larval establishment and the recruitment in the module recifal. / Com o propósito de analisar a ictiofauna do ambiente natural do Arquipélago de Currais, localizado no litoral paranaense, e de um recife artificial instalado nas proximidades das ilhas, foram desenvolvidos os distintos estudos apresentados na forma de quatro capítulos. O capítulo I teve como objetivo descrever a variação espacial na distribuição e abundância de peixes entre quatro zonas geomorfológicas das ilhas rochosas do arquipélago e no módulo artificial. As famílias mais abundantes foram Pomacentridae, Labridae, Scaridae, Sparidae e Labrisomidae. A análise de similaridade entre a abundância e as zonas mostrou que não foram significativas as diferenças para as lajes e parcel e o módulo recifal. A profundidade e grau de exposição ao mar agitado foram as variáveis físicas responsáveis pela heterogeneidade das abundâncias das espécies nas áreas do costão periférico, lajes e parcel, costão vertical e módulo recifal. As diferenças em termos de equitabilidade e riqueza de espécies podem ser devidas às mesmas variáveis. A análise inversa mostrou que foram poucas espécies características em cada agrupamento, portanto as diferenças entre as zonas parecem refletir à dominância de certas espécies. As categorias tróficas dominantes foram planctófagos e herbívoros, os quais foram significativamente diferentes entre as zonas. Nas zonas mais rasas (lajes e parcel) e com alta exposição às condições do mar (costão periférico) predominaram os herbívoros e omnívoros, enquanto que nas profundas (módulo recifal, costão vertical e rochedos escarpados) os mais abundantes foram os planctófagos. Os carnívoros mostraram diferenças significativas entre as zonas protegidas (lajes e parcel). No capítulo II foi abordada a variação nictemeral das três ilhas rochosas apenas do arquipélago. Os resultados quali-quantitativos mostraram a amplitude de distribuição e repartição de nichos entre as espécies. As diferenças significativas observadas entre as amostragens diurnas e noturnas foram evidentes devido ao maior número de espécies capturadas durante a noite, momento do ciclo em que apareceram representadas todas as espécies encontradas no trabalho. Nas amostragens diurnas, foram significativamente mais abundantes as espécies Anisotremus surinamensis, A. virginicus, Holocentrus ascensionis e Stegastes fuscus, enquanto que as noturnas foram caracterizadas pela presença de espécies predadoras ativas como Serranus flaviventris, Lutjanus analis, Cynoscion jamaicensis, Haemulon steindachneri, Abudefduf saxatilis, Diplodus argenteus, Mycteroperca bonaci e Epinephelus adscensionis. As espécies que permitiram diferenciar os habitats diurnos e noturnos foram praticamente as mesmas, o que demonstrou a grande heterogeneidade espacial que apresenta a ictiofauna associada aos ambientes do arquipélago. O capítulo III tratou da análise trófica do esparídeo Archosargus rhomboidalis relacionando com os aspectos do uso de habitat e predação em uma das ilhas do arquipélago (Grapirá) e o módulo recifal. A fonte de variação observada entre as duas áreas amostradas apresentou diferenças significativas entre as épocas do ano. Na Ilha Grapirá as presas mais importantes no outono foram as ascídias e os anfípodos, enquanto que no inverno e primavera foram os anfípodos. Na área dos recifes artificiais, macroalgas e algas foram mais importantes no verão, algas e hidrozoários no outono, algas e briozoários no inverno, e copépodos harpacticoides e anfípodos gamarídeos na primavera. A. rhomboidalis pode ser considerada uma espécie generalista eurifágica que se alimenta de um amplo espectro de presas. No capítulo IV o recrutamento no módulo recifal foi analisado pela categorização dos comprimentos das espécies mais abundantes. A ictiofauna foi analisada ao longo do gradiente temporal com o objetivo de avaliar a eficiência da atratividade ou da produtividade do recrutamento de peixes. Os resultados indicaram que não houve diferenças significativas na contribuição qualitativa e quantitativa de indivíduos subadultos ou juvenis tardios por longos períodos no tempo no módulo recifal. A estrutura parece funcionar como atratora e concentradora de peixes adultos procedentes de fundos rochosos próximos. Os fatores que puderam determinar o caráter atrativo-concentrador para indivíduos adultos foi o desenho estrutural e a localização geográfica onde foi implantado o módulo recifal. O fluxo larval proveniente das massas de água da Plataforma Continental e da Baía de Paranaguá aparentemente não favorece o assentamento larval e o recrutamento no módulo recifal.
227

Anfipodes gamarideos associados a bancos de Sargassum (Phaeophyceae, Fucales) em ambientes sujeitos a contaminação por hidrocarbonetos de petroleo / Gammaridean amphipods associated to Sargassum beds (Phaeophyceae, Fucales) from sites submitted to petroleum hydrocarbons contamination

Pavani, Lilian 14 August 2018 (has links)
Orientador: Fosca Pedini Pereira Leite / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-14T00:36:25Z (GMT). No. of bitstreams: 1 Pavani_Lilian_M.pdf: 1390022 bytes, checksum: 43df8a085a06d86b5eadaf092c0fbf14 (MD5) Previous issue date: 2009 / Resumo: Na região do Canal de São Sebastião, onde opera o maior terminal petrolífero do Brasil, há extensos bancos de algas pardas do gênero Sargassum e anfípodes associados, mas também existem hidrocarbonetos alifáticos e aromáticos de petróleo na água e no sedimento. Sabese que os anfípodes são eficientes bioindicadores de qualidade ambiental, assim como as algas são importantes bioacumuladores. Avaliou-se a presença de hidrocarbonetos em Sargassum e buscou-se relacionar suas concentrações com distâncias crescentes a partir do terminal, tanto ao norte quanto ao sul da Ilha de São Sebastião. Essas concentrações e distâncias também foram utilizadas para verificar a estruturação das comunidades de anfípodes do fital de Sargassum. Essa avaliação foi feita para anfípodes, abordando-se a composição de grupos tróficos e de espécies. Não foi constatada relação entre as distâncias e concentrações de hidrocarbonetos presentes nas algas e na estruturação das comunidades de anfípodes em nenhuma das abordagens. No entanto, notou-se correspondência entre elas, o que indica que a identificação em famílias para o estabelecimento de grupos tróficos pode ser eficiente numa avaliação ambiental mais rápida. Também se obteve importante informação em relação à fauna de anfípodes do litoral do Estado de São Paulo, uma vez que ainda não havia estudos na Ilha de São Sebastião e a fauna de ilhas do estado ainda é pouco conhecida / Abstract: In the São Sebastião Channel region, where operates the greatest Brazilian petroliferous terminal, there are extensive banks of the brown seaweed Sargassum with many associated amphipods, but also polyciclic aromatic hydrocarbons and aliphatic hydrocarbons, which are present both in sedment and water. The amphipods are known to be efficient bioindicators of environmental quality, as well as the seaweed are important bioacumulators. The presence of hydrocarbons in Sargassum and its relationship with increasing distances from the terminal, both north and south of the São Sebastião Island, was evaluated. These concentrations and distances were also used to verify the structure of amphipod communities associated to Sargassum . This evaluation was made for amphipods identified in trofic groups and in species. There was no significant relationship between distances from the terminal and concentrations of hydrocarbons in the seaweed or the estructure of the amphipod communities. However, correspondence between the aproachs (trofic groups and species) was noticed, which indicates that the identification in families for the establishment of trofic groups can be efficient in a faster ambient evaluation. Also, important information related to amphipods of the São Paulo State coast was achieved, as far as the fauna of São Sebastião Island was first studied and the islands fauna of the State are still little known / Mestrado / Ecologia / Mestre em Ecologia
228

Coastal dune ecology and management in the Eastern Cape

Avis, Anthony Mark January 1993 (has links)
The importance of understanding the ecological functioning of coastal dune systems is emphasized as being fundamental to the correct management of the dune landscape. Dune vegetation along the Eastern Cape coastline, from Cape St Francis in the west to Kei Mouth in the east was described in terms of the distribution and phytochorological affinities of the taxa. At a regional scale species distribution was strongly influenced by both the climate, particularly rainfall, and the phytochorological affinities of the taxa. Seven communities were defined using TWINSPAN, and the interrelationships between these communities in anyone area appeared to be linked to a successional gradient. Dune Slacks are thought to play a key role in this successional sequence, and a temporal study of this community led to a conceptual model of plant succession in these dunefields. Climate, particularly rainfall and wind, are major factors influencing plant succession. Wind-borne sand causes the slacks to migrate in an easterly direction under the influence of the predominantly westerly winds, although easterly winds, mainly in summer months may reverse these trends. Autogenic changes appeared to be important in this succession, and a comparative study of a good example of a primary succession at Mtunzini in Natal was undertaken to elucidate the main mechanism of change. Eight communities that were identified here were concluded to be distnbuted along a gradient of increasing age, with successional changes predictable, linear and directional. Species were grouped in distinct zones along the continuum and edaphic changes (decrease in soil pH, increase in organic matter and exchangeable bases) were related to the community based changes in species composition. The mechanism of change supported the facilitation model of plant succession which is a modification of the original Clementsian concept. Similar results were found in the Eastern Cape, but due to the harsh environment, multiple pathways of succession exist. Data from this study lent support to the model of plant succession developed earlier, and confinned that the dune slacks played an important role in this facilitation by acting as centres of diversity. The foredunes were found to have an indirect role in protecting these slacks from salt spray and sand movement. The central theme of the management studies was to investigate the ecological consequences of recreational pressure within the dune environment. Current levels of beach utilization at East London were lower than other beaches in South Africa, but a general trend of increasing utilization due to sociopolitical changes can be expected. The suitability of questionnaire surveys to assess aspects such as the adequacy of facilities, perceptual carrying capacity and the beach users opinion of natural vegetation and preference for particular beaches was demonstrated. The dune vegetation was found to be sensitive to human trampling, but at current levels, the ecological carrying capacity will not be exceeded since results of the aerial census counts and questionnaire survey revealed that few people entered sensitive zones such as the coastal forest. More detailed long term studies on the susceptibility of dune vegetation to both trampling and off-road vehicle impacts revealed a low resilience of dune plant communities to these effects. Although susceptibility differed between the three communities tested, generally the greatest amount of damage occurred after the first few passages, and vehicles caused a more significant decrease in height when compared to trampling. Recovery rates were slow and low levels of repeated damage were sufficient to retard or prevent the recovery of the plants. Stricter control of vehicle use on beaches is therefore required, and in high use zones the ecological carrying capacity should be increased by providing access tracks if possible, or if not possible, by restricting access. A historical account of the process of dune stabilization showed that although first initiated in 1845, indigenous species were only used in the past three decades. The use of alien species has resulted in problems such as a reduction in the ecological integrity and aesthetic appeal of coastal systems. The techniques applied in the stabilization of drift sands with indigenous vegetation have been successful, as revealed by a quantitative survey of 17 sites in the Eastern Cape. Sites were grouped by multivariate analysis on the basis of their species composition, and variability between sites was dependent on the types of species planted. Selection of suitable species is therefore important and is discussed with respect to their natural distribution along the coast. The long term objective of stabilization should be the creation of functional, diverse, aesthetic ecosystems, since the intrinsic and economic value of the dune landscape for tourism lies therein. However, detailed studies should be undertaken prior to implementing a manipulative process such as dune stabilization, since ecological processes may be disrupted. An understanding of such processes is therefore important if one wishes to effectively manage the dune landscape.
229

Extreme Hydrodynamic Loading on Near-Shore Structures

Al-Faesly, Taofiq Qassim January 2016 (has links)
The main objective of this study was to investigate and quantify the impact of extreme hydrodynamic forces, similar to those generated by tsunami-induced inundation, on structural elements. As part of a comprehensive experimental program and analytical study, pressures, base shear forces, and base overturning moments generated by hydraulic bores on structural models of various shapes were studied. In addition, the impact force induced by waterborne wooden debris of different shapes and masses on the structural models was also investigated. Two structural models, one with circular and the other with square cross-section, were installed individually downstream of a dam-break wave in a high-discharge flume. Three impounding water heights (550, 850 and 1150 mm) were used to produce dam-break waves, which have been shown to be analogous to tsunami-induced coastal inundation in the form of highly turbulent hydraulic bores. Time-history responses of the structural models were recorded, including: pressures, base shear forces, base overturning moments, lateral displacements, and accelerations. In addition, the flow depth-time histories were recorded at various locations along the length of the flume. Regular and high-speed video cameras were used to monitor the bore-structure interaction. The effect of initial flume bed condition (“wet” or “dry” bed) on the forces and pressures exerted on the structural models were also investigated. Moreover, the vertical distribution of pressure around the models was captured. Simple low-height walls with various geometries were installed upstream from the structural models to investigate their efficiency as tsunami mitigation measures. The experimentally recorded data were compared with those estimated from currently available formulations. The results and analysis of the simulated tsunami-induced bore presented in this study will be of significant use to better estimate forces exerted on structures by tsunami-induced turbulent bores. It is expected that this work will contribute to the new ASCE7 Chapter 6 - Tsunami Loads and Effects in which two of this author’s academic supervisors, Drs. Ioan Nistor and Dan Palermo, are members.
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Strandnära bebyggelse : En kartläggande studie av faktorer som påverkar den strandnära bebyggelsen i Sveriges kommuner och regioner år 2018 / Beachfront buildings : An analytic study of factors that affect the beachfront development in Sweden's municipalities and regions in 2018

Ottosson, Johan, Mård, Kevin January 2021 (has links)
Debatten om strandskydd har varit ett aktuellt ämne sedan riksdagen antog den första permanenta strandlagen år 1953. Sveriges 290 kommuner och 21 regioner innehar varierande geografiska förutsättningar och ställs inför olika utmaningar. Landsbygdens krympande utveckling gav upphov till framväxten av LIS men har framväxten av LIS bidragit till en ökad strandnära bebyggelse? Utbytet mellan stad och land är idag mer intensivt än tidigare. Uppsatsen syftar till att undersöka vilka faktorer som påverkar utvecklingen av strandnära bebyggelse och skapa förståelse varför det byggs fler strandnära byggnader på olika geografiska platser. Vidare syftar uppsatsen till att kartlägga den strandnära bebyggelsen i Sveriges samtliga 290 kommuner och 21 regioner för år 2018. Syftet har resulterat i följande frågeställningar: Hur ser utbredningen av strandnära bebyggelse ut i Sveriges kommuner och regioner och var är strandnära bebyggelse mest koncentrerat? Vilka faktorer påverkar strandnära bebyggelse? Har utpekandet av LIS-områden bidragit till mer strandnära bebyggelse? För att besvara frågeställningarna genomfördes en totalundersökning med den kvantitativa metoden sekundäranalys av offentlig statistik. Studiens kartläggning av strandnära bebyggelse år 2018 visade att det byggdes mest i städer och i anslutning till städer med pendlingsavstånd. Om hänsyn till demografin och befolkningsmängden beaktades visade studien att det byggdes mest på landsbygden. Studien visade att faktorerna geografisk komposition, antal sjöar och antal kilometer strandlinje påverkar hur mycket det byggs i strandnära läge medan faktorn politisk styre inte hade någon påverkan. Vidare visade studien att kommuner med utpekade LIS-områden inte har påverkat eller bidragit till en ökad strandnära bebyggelse i jämförelse med kommuner som inte har utpekade LIS-områden. / The debate on shoreline protection has been a topical issue since the Swedish Parliament adopted the first permanent law of shoreline protection in 1953. Sweden's 290 municipalities and 21 regions have varying geographical conditions and are faced with various challenges.The shrinking development of rural areas gave rise to the growth of LIS, but does the emergence of LIS contribute to an increase in beach development? The exchange between city and countryside is more intense today than before. The essay aims to investigate which factors affect beachfront development and create an understanding of why more beachfront buildings are being built in different geographical locations. Furthermore, the essay aims to analyze the beachfront development in all of Sweden's 290 municipalities and 21 regions for 2018. The purpose has resulted in the following issues: How does the distribution of beachfront buildings look like in Sweden's municipalities and regions, and where is beachfront development most concentrated? What factors affect beachfront development? Has the designation of LIS-areas contributed to more beachfront development? To answer the following issues, a comprehensive survey was conducted by using the quantitative method secondary analysis of official statistics. The study's survey of beachfront development in 2018 showed that it was built mostly in cities and connected to cities with commuting distances. If the demographic and population is taken into consideration, the study showed that it was built mostly in the countryside. The study showed that the factors geographical composition, number of lakes, and number of kilometers of shoreline affect the number of buildings close to the beach, while the factor political governance did not affect. Furthermore, the study showed that municipalities with designated LIS-areas have not affected or contributed to increased beachfront development, in comparison with municipalities that do not have designated LIS-areas.

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