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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.
1

The development and implementation of a new land-surface scheme for use in GCMs

Pitman, A. J. January 1988 (has links)
No description available.
2

The geomorphological history of the Gebel Al Akhdar valleys, North-eastern Libya

Hasan, Abed M. T. January 1997 (has links)
No description available.
3

Managing Strategy and Flexibility : A trade-off for Swedish Companies

Palmér, Henrik, Georgzén, Per January 2014 (has links)
Firms are reliant on a suitable fit between the firm and their business environment. Simultaneously environments globally become increasingly unpredictable, jeopardizing firms’ ability to develop and implement strategic directions to achieve a suitable fit. To tackle this challenge theorists call for increased flexibility in strategic processes by increasing strategic flexibility. However, the two concepts of strategy and flexibility work as opposing forces of change and stability. This study aims to explore the complex interplay between the two detached concepts in two large Swedish companies Saab and Ericsson. This paper embraces a qualitative method with semi-structured interviews combining deductive and inductive approaches to analyze the interplay between strategy and flexibility. Earlier theorists within strategic flexibility academia primarily focused on providing a resolution of definitional differences; therefore this study provides a new theoretical framework, comprised of a strategy as a plan approach combined with acknowledging strategic decisions in various intra-firm levels. Findings from this study indicate that firms should constantly consider four different trade-offs: decentralized versus centralized control, valuing short-term versus valuing long-term strategies, relying on individual experience versus planning to manage changes and product- versus market-driven strategies to achieve a beneficial interplay between strategy and flexibility.
4

Využití vodních bezobratlých pro studium environmentálních změn vodních toků / Freshwater macroinvertebrates and their use for assessment of environmental changes in running waters

Kolaříková, Kateřina January 2013 (has links)
The dissertation thesis consists of five articles, bringing together results from investigations of macroinvertebrates in running waters. The use of freshwater macroinvertebrate organisms to assess environmental changes was based on the following facts: a) the presence/absence of taxa provide information about abiotic factors and/or about the pollution status of the site, b) they are indigenous and sedentary species, so that the environmental implications can be related to the site they live on, c) the organisms accumulate xenobiotic elements or compounds, thus reflecting the contaminant level in the environment. Localization of the sampling sites was related to the "hot-spots" of environmental problems. The particular investigations were carried out in the Elbe River catchment and in the Czech mountains on the selected headwater streams of the GEOMON network of the Czech Geological Survey. The Elbe was considered one of the most polluted rivers across Europe in the second half of the past century until the socio-economic transformation after 1989. The headwater streams in the Czech Republic were chosen with respect to the problem of acidification. The ability of bioaccumulation of xenobiotics in macroinvertebrate organisms was used to assess the long-term load of the Elbe ecosystem with trace...
5

Landscape and environmental changes at Memphis during the dynastic period in Egypt

Lourenço Gonçalves, Pedro Manuel January 2019 (has links)
Memphis is considered to have been the main metropolis of dynastic Egypt. For more than 3000 years the settlement played a primary role in political, economic and cultural life of the state, functioning as capital for long periods. Nonetheless, little is known about the setting and archaeology of the city itself, even when compared to other Egyptian settlements. This work investigates the context and archaeology of Memphis, recognising distinctive development phases, and examines potential reasons for historical changes. Sedimentary records of 77 boreholes taken in the area of Mit Rahina are analysed to detect palaeoenvironmental conditions and palaeo-landscape features. Their interpretation is sustained by a multidisciplinary approach drawing together prior archaeological, historical and geomorphological studies. A model reflecting the transformations of Memphis is formulated and multi-scale landscape and environmental changes in the Memphite region over the last 5000 years are established. According to this new model, a settlement was founded during the Early Dynastic Period on a complex of sandbanks which were separated and surrounded by three branches of the Nile. After its foundation and during the Early Dynastic Period and the Old Kingdom, the city grew on the western cluster of sandbanks while the West Channel was losing flow. During the First Intermediate Period and the beginning of the Middle Kingdom extreme floods significantly affected the settlement. It recovered during the Middle Kingdom when large-scale landscape management initiatives and strong interventions on the margins of the Central Channel were undertaken. By the New Kingdom, the Middle Birka was already dry land, mainly as a result of human intervention. The East Channel became the only active branch of the Nile serving the city and the Eastern Koms were intensively settled. In the Late Period the city had expanded to the Northern Koms and the North Birka silted up. During the Ptolemaic Period, the city reached its maximum extension, despite important changes in its status and social-economic background. Subsequently, the importance of the city declined with the end of the dynastic state, while the East Channel started to migrate slowly eastward. The city decayed and was abandoned after a few centuries. Some landscape and environmental changes are positively associated both with urban mutation and with different social, economic and political phases of Memphis' history. Human interventions actively induced the evolution of both landscape and local environment. Events at the supra-regional level, both natural and especially anthropic, also had impact and are linked to changes at Memphis. Conversely, contingencies restricted to the Memphite region influenced the development of the state. Local situations at Memphis-e.g., crisis, disaster, conflict, prosperity, or affluence-could be magnified to the extent that they have been perceived as having affected the state as a whole. The foundation and development of Memphis were tightly interconnected with the fortunes of state and power. The city embodied the cultural and political identity of the state and maintained its prominence through dynastic Egyptian history. Triangular complex cause-effect relations between local changes in Memphis, historical change in Egypt, and climatic and environmental evolution both at regional and supra-regional scales are recognised. The significance of each varied with time, determining the evolution of Memphis and also of dynastic Egypt.
6

MudanÃas na sedimentaÃÃo no estuÃrio do rio Jaguaribe (CE) devido a mudanÃas nos usos do solo / Changes in sedimentation in the estuary of the river Jaguaribe (EC) due to changes in land use

Mario Duarte Pinto Godoy 08 March 2011 (has links)
O rio Jaguaribe à o rio com a maior bacia hidrogrÃfica do CearÃ, possui uma bacia hidrogrÃfica de 75 mil Km que ocupa mais de 50% do estado, no entanto, alteraÃÃes de uso do solo que ocorreram dentro da bacia hidrogrÃfica desse rio e alteraÃÃes climÃticas globais podem estar causando a diminuiÃÃo da profundidade do estuÃrio o que dificulta a navegabilidade nessa regiÃo e prejudica a fauna aquÃtica. O foco desse estudo à os sedimentos depositados em ilhas dentro do baixo estuÃrio e possÃveis Ãreas no entorno que foram consideradas como possÃveis fontes de sedimento para essas ilhas. O plano amostral consistiu em 6 pontos dentro do estuÃrio do rio Jaguaribe onde foram retirados testemunho de sedimento e mais 8 pontos onde foram retirados sedimento superficiais no fundo do rio, nas Ãreas da margem e no campo de dunas. As Ãreas foram escolhidas a partir do mapeamento do estuÃrio, esse mapeamento utilizou imagens dos satÃlites Landsat 5, Quickbird II e Kompsat 2 e cobrem o perÃodo entre os anos de 1988 e 2008. O mapeamento mostrou que as ilhas existentes no estuÃrio sofreram grandes mudanÃas no perÃodo de estudo, ao todo ocorreu um aumento de 31,5 hectares na Ãrea ocupada por vegetaÃÃo de manguezal nas ilhas do estuÃrio. O perÃodo de maior crescimento foi o perÃodo entre 1992 e 2003 onde ocorreu um aumento de 6 hectares com uma velocidade de 2,1 hectare por ano. AlÃm do mapeamento foi realizada uma estimativa de carga de sedimento dos diversos usos do solo na bacia hidrogrÃfica do baixo estuÃrio, essa estimativa mostrou que as principais atividades que contribuem com sedimento para o estuÃrio à a agricultura (282.322 t/ano), sendo os principais contribuintes as plantaÃÃes de feijÃo, de mandioca e as de milho. Seguem-se as Ãreas urbanas (115.076 t/ano), as fazendas de camarÃo (13.475 t/ano) e a pecuÃria (1.374/ano). Ao contrÃrio de todas as outras atividades encontradas na Ãrea de estudo, o cultivo de camarÃo à a Ãnica atividade em que a carga de sedimento à lanÃada diretamente no estuÃrio. A granulometria dos testemunhos mostrou um predomÃnio de areias sobre as outras classes, alÃm disso, mostrou que em um mesmo testemunho podem existir diversos tipos de sedimento, havendo camadas com grande quantidade de silte e argila e camadas formadas basicamente de grÃos mais grosseiros, a aparÃncia semelhante com os sedimentos retirados das margens aponta as diversas Ãreas de erosÃo encontradas espalhadas pelas margens do rio como uma possÃvel fonte de grande importÃncia dentro desse contexto. / The Jaguaribe river is the river with the biggest whatershed of Cearà and has a catchment area of 75,000 km  which occupies over 50% of the state, however, land use changes that occurred in the watershed of this river and global climate change could be causing the decrease of the depth of the estuary which can make impossible for ship to navigate in the estuary and affect the aquatic fauna. The focus of this study is the deposited sediment in islands within the estuary and the surrounding areas which were considered as possible sources of sediment to these islands. The sampling plan consisted in 6 point within the estuary of the Jaguaribe river where were taken sediment cores and further 8 points where were taken superficial sediment from the bottom of the river, from areas in the margin of the estuary and from the dune fields near the estuary. The sampling locals were chosen based on the mapping of the estuary, this mapping used images from the satellites Landsat 5, Quickbird II and Kompsat 2 and cover the period of time between the years of 1988 and 2008. This mapping showed that the existing islands in the estuary suffered great changes during this period, overall there was an increase of 31.5 hectares in the area colonized by mangrove vegetation in the islands. The period of greatest growth was the period between 1992 and 2003 where there was an increase of 6 hectares with a speed of 2.1 hectare per year. In addition to mapping was performed an estimative of sediment load from various land uses in the watershed of the lower estuary, the estimative showed that the main activities that contribute sediment to the estuary is agriculture (282,322 t / year), with the main contribution being from plantations of beans, cassava and corn. Following are the urban areas (115,076 t / year), the shrimp farms (13,475 t / year) and livestock (1,374 t / year). Unlike all the other activities found in the study area, shrimp farming is the only activity in which the sediment load is released directly into the estuary. The diameter of the sediment from the samples showed a predominance of sand on the other classes and also showed that in a same profile may be different types of sediment, with layers with large amounts of silt and clay and layers formed primarily of coarser grains, the appearance of this sediment is similar from the sediment removed from the margin of the estuary and indicates that the several areas of erosion found scattered along the margin of the river may be possible source of great importance within this context.
7

Influence of Abiotic Environmental Factors on Physiological Responses and Mixotrophy in Freshwater and Marine Chrysophytes

Chang, Chia-Mei 05 1900 (has links)
Global climate change represents one of the greatest threats to biodiversity. Phenomena such as rising surface water temperature, increased UV radiation, and ocean acidification have brought negative impacts to ecosystems and their inhabitants. Sensitive to various abiotic factors, microbial eukaryotic communities in aquatic systems are particularly being affected by these environmental changes. Specifically, warming temperature not only can directly affect plankton through limiting growth and inhibiting physiological processes, but can also indirectly impact these organisms by altering light and nutrient availability via loss of sea ice and changes in thermal stratification in various environments. Mixotrophic chrysophytes are an important lineage of protists that often dominate phytoplanktonic blooms in both freshwater and marine systems. Studies have shown mixotrophic organisms’ nutrient-acquiring strategies are influenced by abiotic environmental factors. Temperature in particular, is known to alter growth rate and bacterivory. In response to rising temperature, mixotrophs can either become more phototrophic or more heterotrophic, depending on species, resulting in changes of their role in aquatic food webs and potentially leading to shifts in overall community composition and structure. The objective of this research is to investigate the influence of different environmental factors on primary production and heterotrophic ingestion in marine and freshwater chrysophytes, providing an understanding on how climate change may alter physiological response and survival, with indicative changes in community structures and food webs. The influence of irradiance, nutrient concentrations, and temperature on mixotrophic responses of the Arctic marine chrysophyte Dinobryon faculiferum was investigated, where our results demonstrated an increase in heterotrophic ingestion in response to rising temperature. We also found bacterivory contributes a major proportion of D. faculiferum’s carbon budget in comparison to primary production, which is different from previous studies on Dinobryon species that appeared to be more reliant on phototrophy. Conversely, the freshwater chrysophyte Chrysolepidomonas dendrolepidota, exhibited the opposite temperature effect. The freshwater species was more reliant on primary production and ingested less as temperature increased. Such varying responses showcased diverse nutrient strategies on the mixotrophic spectrum, suggesting generalization of mixotrophic mode in predictive models should be approached with caution. Additional work was done to gain insight on the biogeography of C. dendrolepidota, of which little is known about its distribution. The presence of C. dendrolepidota was not detected through metadata analysis, nor was it detected across several waterbodies sampled in this study. Our results suggested possible rare distribution and endemism of C. dendrolepidota. / Biology
8

A study of geosynthetic reinforced flexible pavement system

Gupta, Ranjiv 21 June 2010 (has links)
The use of geosynthetics as reinforcement for the base layer of flexible pavement systems has grown steadily over the past thirty years. In spite of the evidence that geosynthetic reinforcements can lead to improved pavement performance, the specific conditions or mechanisms that enable and govern the reinforcement are unclear, largely remaining unidentified and unmeasured. The appropriate selection of design parameters for geosynthetics is complicated by the difficulty in associating their relevant properties to the improved pavement performance. In addition, pavement structures deteriorate under the combined effects of traffic loading and environmental conditions, such as moisture changes. However, these factors have not been studied together in the evaluation of the overall performance of pavement systems. Consequently, this research focused on the assessment of the effect of geosynthetics on the pavement structural section's ability to support traffic loads and to resist environmental changes. Accordingly, the primary objectives of this research were: (i) to determine the governing mechanisms and relevant properties of geosynthetics that contribute to the enhanced performance of pavement systems; (ii) to develop appropriate analytical, laboratory and field methods that are capable of quantifying the above properties for geosynthetics; and (iii) to enable the prediction of pavement performance depending on the various types of geosynthetics used. To fulfill these three objectives, an evaluative, laboratory and field study was performed. The improved performance of pavements due to addition of geosynthetics was attributed to the ability of geosynthetics to laterally restrain the base course material, thereby providing a confinement effect to the pavement. A parameter to quantify the soil-geosynthetic interaction at low displacement magnitudes based on the solution of an analytical model for geosynthetics confined in pullout box was proposed. The pullout tests were then conducted on various geosynthetics to obtain the proposed parameter for various geosynthetics. The quantitative magnitude of the parameter value from the laboratory tests was compared with the qualitative performance observed in the field test sections. Overall, a good agreement was obtained between the laboratory and field results, thereby providing confidence in the ability of the proposed analytical model to predict the governing mechanism for geosynthetic reinforced pavements. / text
9

Environmental Change in South Central Chibuto Southern Mozambique 1965-2000

Ombe, Zacarias Alexandre 01 March 2007 (has links)
Student Number : 9707731W - PhD thesis - School of Geography, Archaeology and Environmental Studies - Faculty of Science / Southern Mozambique has experienced changes in land-use and land-cover over the last 45 years. South Central Chibuto is a dynamic environmental change ‘hotspot’ of this region, and because of the socio-economic development that is taking place it is unveiling a number of land-use changes in Mozambique. In this research, environmental changes in the region are shown to be a function of various socioeconomic and biophysical drivers of change. A variety of research methods including interpretation of aerial photographs and satellite images, analysis of archival material, Participatory Rural Appraisal (PRA) and structured interviews, have been used to derive some of the drivers of environmental change. These drivers of change include socio-economic factors, the colonial dual economy and the increase in cash crop production that led to negative impacts on some lands in the steep slopes of the ancient dunes, the post-independence policy of nucleation of settlements that has induced extensive conversions of land use together with the war and the recent shifts into a market economy that have led to further intensification of land use. The biophysical drivers include, among others but not limited to, fluctuations in rainfall, with periods of alternating dry and wet spells shaping land-use change, as well as single shock events, such as extreme droughts and floods. New factors, including the HIV/AIDS pandemic and globalization have been identified as having an impact on the livelihoods in the study area. A valuable, local-scale case or place-based case study approach is shown to enable a detailed and rich analysis of the complex trajectory of environmental change. Finally, lessons drawn from this study are shown to have the potential to inform policies for sustainable livelihoods in Mozambique.
10

Migrações Ambientais, Direitos Humanos e o Caso dos Pequenos Países Insulares / Environmental Migration, Human Rights and the Case of the Small Island Countries

Mattar, Marina Rocchi Martins 22 June 2012 (has links)
O deslocamento humano causado por efeitos climáticos adversos é, e tem sido por muito tempo, uma estratégia natural de adaptação à variação do meio ambiente. Contudo, estudos prevêem que a frequência de desastres naturais e o impacto negativo da mudança climática no meio ambiente têm aumentado consideravelmente e poderão forçar dezenas, ou talvez centenas, de milhares de pessoas a deixar suas casas - e, em alguns casos, seus países - nas próximas décadas. O direito internacional carece de instrumentos que garantam a proteção das diferentes categorias de migrações ambientais. O presente estudo busca analisar o impacto das alterações ambientais nas dinâmicas de migração e explorar suas implicações políticas e jurídicas. Pretende-se assim, contextualizar o fenômeno no período recente e analisar sua complexidade, buscando identificar as principais variáveis que explicam as hipóteses centrais deste estudo, quais sejam, as de que é improvável que os Estados aceitem se comprometer a um tratado global vinculante sobre migrações ambientais no curto e médio espaços de tempo e, por se tratar de um assunto sobre o qual ainda está longe de se chegar a um consenso e considerando que diversas pessoas já estão sendo forçadas a migrar por causa de alterações ambientais e não podem esperar que um instrumento específico seja criado para que seus direitos fundamentais sejam protegidos, acordos regionais e bilaterais e uma coordenação interagências baseada em um guia de princípios trariam resultados mais imediatos e atenderiam as necessidades específicas de cada comunidade em relação aos direitos humanos. Tais hipóteses serão posteriormente testadas pelo estudo de caso desta pesquisa. / The human displacement caused by adverse weather conditions is, and has been for a long time, a natural strategy to adapt to environmental changes. However, studies predict that, the frequency of natural disasters and the negative impact of climate change have increased significantly and will lead tens, and perhaps hundreds, of thousands of people to flee their homes - and, in some cases, their countries - in the coming decades. International law lacks instruments to guarantee the protection of various categories of environmental migration. This study aims at analyzing the impact of environmental changes in the dynamics of migration and exploring the legal and political implications. Thus, the intention is to contextualize the phenomenon and explore its complexity, seeking to identify the key variables that explain the central hypothesis of this study that it is unlikely that States commit themselves to accept a binding international treaty on environmental migration in the short and medium-term, and considering that environmental migration is a subject far from reaching a consensus and that many people are already being forced to migrate due to environmental changes and can not wait for the creation of a specific instrument so that their fundamental rights are protected, regional and bilateral agreements, and interagency coordination based on guiding principles would bring more immediate results and would meet the specific needs of each community in relation to human rights. These hypotheses are then tested by the case study of this research.

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