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Solar flares are one mechanism to release stored magnetic energy in the Sun’s atmosphere. This thesis aims to determine whether sunspot rotation can inject the energy required for solar flares into the corona. This thesis investigates the relationship between sunspot rotation and solar flares, and the impact that sunspot rotation has on the strength and frequency of flare events. A robust analysis tool is developed which uses continuum images of the Sun to determine the rotation of sunspots. This tool is used throughout the thesis, first on the active region 11158, in an in-depth case study of the rotation and flaring properties of the region as it traverses the solar disc. The case study develops analysis techniques, such as introducing sunspot selection criteria, which are used in the following statistical studies. The first statistical study involves the analysis of the rotation and flaring properties of a sample of all sunspots that meet the selection criteria within all X-class flaring regions since the launch of the Solar Dynamics Observatory. As this first statistical study is biased towards higher flare-energy active regions, a second unbiased statistical study is carried out on all sunspots that meet the sunspot selection criteria between 1 May 2013 and 31 August 2013. The results of these statistical studies are combined and analysed, concluding that sunspot rotation injects enough energy (and in the majority of cases, an excess of energy) to account for the energy output by solar flare radiation. On average, the radiated bolometric flare energy outputs 65.6% of the injected energy due to the absolute sunspot rotation for the X-class flare sample, and 59.2% for the four-month sample.

Solar Energetic Particles (SEPs) are known to be accelerated by high-energy events in the Sun's corona: coronal mass ejections (CMEs) with high speed, solar flares with high peak emission in soft X-rays, or a combination of the two. SEPs, however, are not detected following all fast CMEs or intense flares. Those large solar events, which might reasonably have been expected to produce SEPs at Earth but which failed to do so, may be termed “false alarms”. In this work, two simple SEP forecasting algorithms are defined: one (algorithm A.1) is based upon the observation of a magnetically well-connected CME with a speed of 1,500 km/s or greater (a ``fast CME''), and the other (algorithm A.2) is based upon the observation of a magnetically well-connected X class flare. The algorithms were applied to historical data sets to ascertain which produced an enhancement of >40 MeV protons, and which were false alarms. The algorithms have been evaluated using standard verification scores. Both algorithms correctly forecast approximately the same percentage of SEP events (47% and 49% respectively); the false alarm ratio for algorithm A.1, however, was much lower than for A.2 (29% and 51% respectively). Both algorithms failed to forecast almost the same number of SEP events (53% for A.1, and 51% for A.2). The parameters of the false alarms were compared to those of the SEP-producing events. False alarm fast CMEs tended to be associated with flares of class less than M3; X class flares which were either not associated with any CME, or were associated with a CME slower than 500 km/s, were false alarms. A third forecasting algorithm, based upon these results, was defined. This algorithm, which takes into account parameters of both CMEs and flares, performed better than either A.1 or A.2, correctly forecasting a significantly greater percentage of SEP events than both (68%), having a false alarm ratio similar to A.1 (30%), but missing a significantly lower percentage (32%) of SEP events. A small number of case studies were carried out. It was found that for accurate forecasting of SEP events it may not be sufficient simply to consider the accelerating events, but that the location of the heliospheric current sheet relative to the site of the solar event and of the Earth's footpoint may be an important consideration. SEP forecasts produced by the SPARX simulation were evaluated with a view to providing a benchmark against which future versions of the model may be tested.

Environmental issues from oil production have left inestimable environmental degradation and impacts to the lives of people in the Nigerian oil-producing region (NOPR). Research to date has suggested the importance of stakeholders’ collaboration in managing environmental issues. However, little research has been conducted to understand roles of stakeholders in developing a framework for stakeholders’ collaboration in the NOPR. This research produces a framework for stakeholders’ collaboration to expand knowledge in the development of a collaborative environmental management in the NOPR. The research aim was achieved based on four objectives; 1) identified recommended practices for stakeholders’ collaboration in managing environmental issues and established how they could be applied in the NOPR; 2) investigated stakeholders’ perception of collaborative roles in managing environmental issues in the NOPR; 3) designed a framework for stakeholders’ collaboration for managing environmental issues in the NOPR through the synthesis of outcomes of 1) and 2); and 4) validated the designed framework by identifying the critical success factors for its application. In achieving these objectives, interpretive research was applied, and it was underpinned by stakeholder analysis methodology to provide a coherent research design. Furthermore, the Ostrom’s institutional analysis and development (IAD) framework and the theory of common pool resource were extended to inform the interpretation of collaborative roles of stakeholders in managing environmental issues in the NOPR. Adhering to the theoretical suggestions of stakeholder analysis / IAD framework and to allow a robust investigation of stakeholders’ collaboration, this research focused on the qualitative investigation of roles of the key stakeholders–i.e., Nigerian government agencies, multinational oil companies and host communities. While analysis of selected documents of the key stakeholders was conducted to explore the roles of stakeholders, semi-structured interviews were conducted with a select heads of departments and managers to examine their perception regarding their collaborative roles and critical success factor for stakeholders’ collaboration. While selective manual coding was used for the document analysis, narrative analysis assisted with NVivo 11 was used for the semi-structured interview analysis. The findings from both the document analysis and the review of recommended environmental management practices were synthesized to develop the framework for stakeholders’ collaboration. Policy review and development; strategic environmental management, systematic implementation of environmental management strategies and periodic review of management practices and policies were identified as key components of the framework for stakeholders’ collaboration. Findings from the framework validation derived from the semi-structured interviews show that critical success factors of stakeholders’ collaboration in managing environmental issues in the NOPR are primarily driven by socio-economic interests and political will as well as compliance to environmental management policies. Furthermore, it was found that ignorance and lack of commitment, among other barriers, can hinder stakeholders’ collaboration in managing environmental issues in the NOPR. This research suggests that due to the diversity of stakeholders’ roles regarding their institutional interests and complexity of environmental issues in the NOPR, successful stakeholders’ collaboration would depend on the concerted commitment and genuine collaboration across stakeholders.

This thesis investigates the topology of the magnetic field in the solar corona, due to a variety of source configurations and types. To fully understand the complex behaviour of the Sun's magnetic field, it is important to have a complete description of the features present in its structure. The magnetic topologies due to network source configurations are investigated using both the point source description and the continuous source description. A series of case studies involving an emerging bipole in a hexagonal arrangement to simulate a supergranular cell are studied. This has a particular focus on the behaviour of coronal nulls located in the topology, and a particular case may form the underpinning of a model for polar plumes. A new topological feature, called a null-like point, is defined by relaxing the definition of a magnetic null point. Separatix-like surfaces, originating from null-like points, allow quasi-separatrix layers to be found in magnetic topologies due to continuously distributed sources. The squashing factor, Q, is mapped across the source configuration, highlighting the locations of the quasi-separatrix layers. Finally, an algorithm is developed which automatically detects and classifies magnetic events local to X-ray bright points (XBPs). Significant peaks are identified in the gradients of flux curves (positive, negative and absolute flux) local to XBP footpoints, allowing instances of flux emergence and cancellation to be identified and linked to the onset and demise of the XBPs studied. The algorithm correctly classifies 90% of all emergence and cancellation events related to the studied XBPs.

<p>An organism that is transferred from one place to another, causing major problems to the native species is termed invasive. Its natural dispersal across barriers may have been prevented but as man has turned able to rapidly travel all over the world organisms are brought to sites where they were never before observed. Adding the increasing global warming organisms may find it necessary to move around even further. This might cause major disturbance to the biological diversity, and hybridization and homogenization is one of many scenarios that could disturb the native diversity. In Sweden more that 2/3 of all alien plant species have been introduced to disturbed areas and the major introduction mechanism is gardening. The object of study in this presentation, <em>Pimpinella major</em> (Apiaceae) was introduced in Sweden alongside garden grasses during the 19^th century but has so far spread only marginally from the areas of introduction. The aim of the study was to quantify the appearance of <em>Pimpinella major</em> in different types of vegetation apart from road verges, where it has been noted systematically for over a decade. The investigation area covers most of the Tullgarn nature reserve. The result shows an astonishing tendency of P. major to remain growing only along the roads in the area. The very few findings besides next to roads are from deciduous and coniferous forests and fields. It seems that <em>Pimpinella major</em> almost without exception prefers heavily disturbed areas and access to large amounts of nitrogen fertilizer from exhaust fumes</p>

An organism that is transferred from one place to another, causing major problems to the native species is termed invasive. Its natural dispersal across barriers may have been prevented but as man has turned able to rapidly travel all over the world organisms are brought to sites where they were never before observed. Adding the increasing global warming organisms may find it necessary to move around even further. This might cause major disturbance to the biological diversity, and hybridization and homogenization is one of many scenarios that could disturb the native diversity. In Sweden more that 2/3 of all alien plant species have been introduced to disturbed areas and the major introduction mechanism is gardening. The object of study in this presentation, Pimpinella major (Apiaceae) was introduced in Sweden alongside garden grasses during the 19th century but has so far spread only marginally from the areas of introduction. The aim of the study was to quantify the appearance of Pimpinella major in different types of vegetation apart from road verges, where it has been noted systematically for over a decade. The investigation area covers most of the Tullgarn nature reserve. The result shows an astonishing tendency of P. major to remain growing only along the roads in the area. The very few findings besides next to roads are from deciduous and coniferous forests and fields. It seems that Pimpinella major almost without exception prefers heavily disturbed areas and access to large amounts of nitrogen fertilizer from exhaust fumes

Thesis (doctoral)--Freie Universität Berlin, 2004. / "April 2004"--P. [2] of cover. Lebenslauf. Includes bibliographical references (p. 182-[199]). Also available on the World Wide Web.

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Thesis (M.S.)--Oregon Graduate Institute of Science and Technology, 1990.