abstract: As much as 40% of the world's human population relies on rivers which originate on the Qinghai-Tibetan Plateau (QTP) (Xu et al. 2009, Immerzeel et al. 2010). However, the high alpine grasslands where these rivers emanate are at a crossroads. Fed by seasonal monsoon rains and glacial runoff, these rivers' frequent flooding contributes to massive losses of life and property downstream (Varis et al. 2012). Additionally, upstream grasslands, which regulate the flow of these rivers, are considered to be deteriorating (Harris 2010). This thesis examines the regional vulnerability of these rivers and highlights the impacts of several policy responses, finding that both climate change and grassland degradation pose significant challenges to Asia's water security. Additionally, I suggest that many of the responses elicited by policy makers to meet these challenges have failed. One of these policies has been the poisoning of a small, endemic, burrowing mammal and keystone species, the plateau pika (Ochotona curzoniae) (Smith and Foggin 1999). Contrary to their putative classification as a pest (Fan et al. 1999), I show that the plateau pika is instead an ecosystem engineer that actively increases the infiltration rate of water on the QTP with concomitant benefits to both local ecosystems and downstream hydrological processes. / Dissertation/Thesis / M.S. Biology 2012

A trusted execution environment (TEE) is an isolated environment used for trusted execution. TEE solutions are usually proprietary and specific for a certain hardware specification, thereby limiting developers that use those TEEs. A potential solution to this issue is the use of open-source alternatives such as the TEE framework Keystone and the Reduced Instruction Set Computer V (RISC-V) hardware. These alternatives are rather young and are not as well established as the variants developed by ARM and Intel. To this end, the assurance in Keystone and RISC-V are analysed by studying a remote attestation assurance use case using the goal structuring notation (GSN) method. The aim is to investigate how GSN can be utilised to build assurance cases for TEEs on RISC-V. This thesis presents a process of how GSNs can be created to argue assurance for a TEE solution. Furthermore, Keystone operates under a specific threat model with made assumptions that may have a large impact depending on the use case. Therefore, Keystone is analysed to understand whether the framework mitigates existing vulnerabilities in TEEs. It is concluded that GSN is a viable method for arguing assurance in TEEs, providing great freedom in the creation of the GSN model. The freedom is also its weakness since the argument composition has a high impact on the argument. Furthermore, we conclude that Keystone mitigates multiple known vulnerabilities primarily through made assumptions in its threat model. These cases need to be considered by developers utilising Keystone to determine whether or not the assumptions are valid for their use case.

Global industries are characterized by complex networks of organizations, which are often dominated by a few disproportionately large transnational corporations. While industry consolidation is not a new phenomenon, the scale and speed at which global industries now impact diverse social-ecological systems is unprecedented. In this thesis, I combine the interconnected perspective of business ecosystems with the sustainability focus of the social-ecological systems literature through the concept of keystone actors. Adopting a network perspective, I apply this framing to the global clothing industry, and specifically analyze the patterns of coordination and collaboration among actors working to address systemic sustainability challenges facing the industry. While keystone actors wield significant influence over both the industry’s biophysical and socio-economic impacts, I find it is the presence of key brokers – actors who mediate indirect connections between keystone actors in the clothing industry – that possess the potential to coordinate action around sustainability challenges into a collective industry-wide effort. I conclude the thesis by discussing how the empirical findings, and network perspective more generally, can advance the study of keystone actors in global business ecosystems.

Syfte: Syftet med denna studie var att experimentellt bestämma om Parvimonas micra ökar tillväxt och gingipainaktiviteten hos olika stammar av Porphyromonas gingivalis. En ökning av gingipainaktiviteten indikerar att P. micra skulle kunna öka virulensen i P. gingivalis.Material och metod: Fem stammar av P. gingivalis 1A, 16A, 50A, 33F och W50 odlades med P. micra och jämfördes med kontrollen som endast innehöll P. gingivalis. Arginin gingipain (Rgp) och lysin gingipain (Kgp) aktivitet mättes med hjälp av Bikkam-16 respektive Bikkam-14. Bakterietillväxt mättes genom att mäta optisk densitet.Resultat: Experimenten visade en ökad tillväxt av stammarna 1A, 16A och 50A när de odlades med P. micra, 33F visade måttlig tillväxt och W50 ingen tillväxt.Rgp aktiviteten ökade i vissa P. gingivalis-stammar (1A och 16A) i närvaro P. micra men ökade inte i andra (W50, 33F och 50A)Kgp aktiviteten ökade i P. gingivalis lA i närvaro av P. micra men ingen ökning skedde i de andra stammarna (16A, W50, 33F och 50A).Slutsats: Resultaten från denna studie visade att P. micra påverkar tillväxten och gingipainaktiviteten hos vissa stammar av P. gingivalis men inte alla. / Aim: The aim of this study was to experimentally determine if Parvimonas micra increase growth and gingipain activity in different strains of Porphyromonas gingivalis. An increase in gingipain activity could indicate that P. micra induces pathogenic expression of P. gingivalis.Material and method: Five strains of P. gingivalis 1A, 16A, 50A, 33F and W50 was cultivated together with P. micra while control samples contained only P. gingivalis. Activity of arginine gingipain (Rgp) and lysine gingipain (Kgp) was measured using Bikkam-16 respectively Bikkam-14. Bacterial growth was determining by measuring the optical density.Results: The experiments show an increased growth of some strains (1A, 16A and 50A) of P. gingivalis when grown with P. micra, one showed moderate growth (33F) and one showed no growth (W50).The gingipain activity (Rgp) increased in P. gingivalis strains (1A and 16A) in the presence of P. micra but did not increase in other strains (W50, 33F and 50A)The gingipain activity (Kgp) increased in one P. gingivalis strains (1A) when mixed with P. micra and did not increase in others (16A, W50, 33F and 50A). Conclusion: The results from this study indicates that P. micra effect the growth and gingipain activity in certain strains of P. gingivalis but not all.

Beavers have been described as a “keystone species” and “ecosystem engineers”, and in this dual role have great potential to physically modify their environment through tree-felling, foraging and construction activities. The resultant change in habitat heterogeneity can affect the flora and fauna that share the habitat with them. There has been recent interest in reintroducing the Eurasian beaver to the United Kingdom after an absence of over 400 years. To date, no research (aside from this thesis) has focussed on beaver ecology and behaviour in Scotland. This study has investigated the ecological effects of a small number of beavers in two enclosed but semi-natural Scottish sites at Bamff in Perthshire. The research conducted over a three-year period, with particular emphasis on the effects of tree-felling, foraging and construction activities. Trees were felled for both dietary and construction purposes, with felling rates being influenced by habitat availability, quality and the degree of habitat modification required. Highest rates were evident during the initial colonisation period of marginal sites (c. >300 trees / beaver / calendar year), and lowest rates in later years of occupation of more optimal sites (c. 55 – 70 trees / beaver / calendar year). Preferences were generally for willow and aspen trees, with conifers almost entirely avoided, and smaller trees preferred over larger ones. Proximity of trees to waterbodies was also an important factor, with nearer trees favoured, and generally most felling occurred within 50 m of water. Such behaviour followed the principles of optimal central place foraging. These preferences were less predictable however when intense construction activity was undertaken, with larger trees preferred and generic preferences for deciduous trees apparently invalid. In such cases, close proximity to the construction site was of prime importance. Increased cover of herbaceous plant species was observed in beaver-created canopy gaps in riparian woodland, whilst macrophyte diversity within waterbodies increased slightly in areas of herbaceous grazing. The diversity of terrestrial ground invertebrates was highest in areas of heavy tree-felling, and invertebrate richness and abundance was greatest in areas of herbaceous grazing under an intact tree-canopy. Furthermore, the abundance, diversity and richness of macroinvertebrate communities were increased by beaver-generated woody debris in ponds and streams. Overall, 30% of all macroinvertebrate species collected were found only in beaver-affected areas, due to the refugia and food supply provided by beaver dams, caches and lodges, as well as hydrological effects of these structures. These results are discussed with reference to future plans to return the beaver to Scotland. The habitat usage and modification of riparian ecosystems in northern Britain is likely to be similar to that found in this study, and the results are believed to be relevant, applicable and transferable to many areas of Scotland.

<p>The minimum ecologically viable population size (MEVP) of a species describes the minimum size at which the species itself or another species in the same ecosystem goes extinct as a result of the loss of inter-specific interactions. The MEVP shows a good potential for use as a tool for exploring the mechanisms behind species extinctions, but presently only a small amount of research has been done that takes advantage of this. In this study the MEVP is used to investigate what properties of species can be used as good indicators of ecological importance. 100 large computer generated food webs were created with an assembly model and the reduction in density that was necessary to induce an extinction event in the web was subsequently determined for each species within the webs. This change in density was then correlated with 28 different properties, measured for each species. The results show that properties that measure how well connected a species is, as well as measures of the species role as a prey item in the web are the ones with the greatest potential to find species with high MEVP. Further, the results put emphasis on the importance of regarding the web as a whole when working with species extinctions, while also highlighting the usefulness of the MEVP concept.</p>

The minimum ecologically viable population size (MEVP) of a species describes the minimum size at which the species itself or another species in the same ecosystem goes extinct as a result of the loss of inter-specific interactions. The MEVP shows a good potential for use as a tool for exploring the mechanisms behind species extinctions, but presently only a small amount of research has been done that takes advantage of this. In this study the MEVP is used to investigate what properties of species can be used as good indicators of ecological importance. 100 large computer generated food webs were created with an assembly model and the reduction in density that was necessary to induce an extinction event in the web was subsequently determined for each species within the webs. This change in density was then correlated with 28 different properties, measured for each species. The results show that properties that measure how well connected a species is, as well as measures of the species role as a prey item in the web are the ones with the greatest potential to find species with high MEVP. Further, the results put emphasis on the importance of regarding the web as a whole when working with species extinctions, while also highlighting the usefulness of the MEVP concept.

No description available.

People are active participants in coral reef ecosystems. This ethnobiology study considers and contrasts folkbiological knowledge of people living in two groups of artisanal fishing villages in Kadavu Province, Fiji. The high level of biological diversity on the Astrolabe Reef provides insights into folk categorization and classification methods that include colour, shape, size, physical features, and habits of certain reef fish and marine animals. Surveying large numbers of experts and novices on defined groups of creatures yields more depth and range of responses allowing higher confidence levels in response accuracy. A comparison of the data with Berlins (1992) proposed principles yields mixed results. Sea cucumbers have high ecological salience and their identification requires attention to the affect of two centuries of trade on Fijian society. Effective ethnobiological research provides productive options to contribute to coral reef sustainability programs with long term benefits for local people and marine life. Key words: Kadavu, naming and classification of fish, coral reef ethnobiology.

No description available.