Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2001. / Härtill 6 uppsatser.

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Numerous "Fynbos" species of the Cape Floristic Region (CFR) have particularly fine, narrow leaves. The rates of transpiration and heat loss are partially dependent on boundary layer conductance, which is determined by leaf shape and size, surface modifications and wind speed. We expected fine-leaved species with higher boundary layer conductance to transpire faster than broad-leaved species at low temperatures whereas at higher temperatures we expected transpiration to be limited by stomata! conductance. In contrast, the rate of heat loss may be constrained by thick boundary layers in larger leaves at high temperatures. Leaf gas exchange characteristics at various temperatures were correlated with boundary layer thickness, leaf area and specific leaf area for 14 Proteaceae species using phylogenetically independent contrast species. When the temperatures of individual leaves were altered, while ambient temperature was kept at l 8°C, water loss decreased significantly at both 12°C and 30°C with increased leaf size and thus boundary layer thickness. At 30°C, small leaves with thin boundary layers resulted in leaf temperatures below ambient, while larger leaves with thicker boundary layers had leaf temperatures closer to ambient. However, at 30°C the variation in leaf temperature between the smallest and largest leaves was only 3.4°C. Such a small variation in leaf temperature is unlikely to alter temperature-dependent physiological processes. We conclude that the small boundary layer associated with small leaves enables fine-leaved species to transpire at faster rates when water is plentiful. This may be a particularly important strategy for plants that take up most of their nutrients in the wet winter months from nutrient-poor highly leached soils of the CFR region. We suggest that fine leaves are an adaptation for nutrient uptake during winter, although they may also have the benefit of improved coupling of leaf to ambient temperature during the summer drought period.

The removal of marine species through fishing has impacted marine ecosystems for thousands of years. The pressure of exploitation on marine ecosystems has now reached a point at which there is serious concern over ecosystem well-being on a global scale. There has, therefore, been a global move towards an ecosystem approach to fisheries management. The objective of this study was to develop a decision tree framework to assess the status of exploited marine ecosystems, which could be successfully applied to numerous ecosystems and guide decision support under changing conditions. This work was based on that of the IndiSeas project, which makes use of indicators designed to detect the impacts of fishing on marine ecosystem around the world. A suite of indicators, selected from those utilised in the IndiSeas project, was divided into ecological and fishing pressure indicators. Ecosystem specific suites of environmental indicators were also included, allowing the framework to ascertain the impacts of environmental variability on ecosystem components. This is an important addition as currently many assessments of the impacts of fisheries do not account for the influence of the environment. The framework was developed for the Southern Benguela ecosystem and then applied, with minor adjustments to account for ecosystem-specific characteristics, to the South Catalan Sea and North Sea. Indicator time series were analysed making use of linear regressions, resulting in the assignment of a score between one and five, depending on the direction and significance of trends. Data series were divided into distinct periods based on known environmental changes or shifts within ecosystems. Careful consideration was given as to whether fishing and environmental indicator trends could explain the observed trends in ecological indicators. A method of score adjustment was then developed to account for the impacts of both fishing and environmental variability on ecological indicators. Correlations were conducted to detect potential redundancies of ecological indicators and weightings were applied to decrease the contribution of correlated indicators to overall ecosystem trends. However, as correlations differed between indicators and amongst ecosystems, it was necessary to adjust the applied weightings for individual ecosystems. Results for the Southern Benguela classified the ecosystem as neither improving nor deteriorating during Period 1 (1978-1993) and Period 2 (1994-2003). During Period 3 (2004-2010) the ecosystem was classified as possibly improving. The South Catalan Sea was classified as possibly deteriorating during Period 1 (1978-1990) and neither improving nor deteriorating during Period 2 (1991-2010). The North Sea ecosystem was classified as neither improving nor deteriorating during Period 1 (1983-1992). During the second (1993-2003) and third (2004-2010) periods the ecosystem was categorised as possibly improving. When assessing fisheries impacts at an ecosystem scale there are typically high levels of uncertainty. However, this thesisoncluded that the development of a scoring and weighting system, alongside the addition of environmental drivers and the inclusion of expert knowledge throughout the applications of this framework, has allowed the developed decision tree framework to successfully categorise the three ecosystems. It is anticipated that the knowledge that this framework will add to current methods of generating advice for fisheries management will aid future decision support within these ecosystems.

O setor de software e seu uso vêm crescendo em todo o mundo, incluindo o Brasil. Observa-se um panorama de mudanças na produção de software, com tendência crescente de desenvolvimento em parcerias em vez do modelo tradicional. Nessa nova abordagem, chamada de Ecossistema de Software (ECOS), uma empresa constrói uma comunidade de desenvolvedores ao redor de seu produto principal para atender melhor às crescentes demandas de seus clientes. O entendimento dessas mudanças e seus impactos nas empresas atuantes nesse setor no Brasil é importante e ainda se encontra em maturação Entre as lacunas estão a criação de modelos para estudo e caracterização de ECOS, além do estudo de seus aspectos de negócio, sociais e técnicos. Este trabalho concentrou-se na análise dos dois primeiros aspectos, com foco em como atores chamados niche players (ou parceiros) têm que se adaptar para atuar de acordo com a nova abordagem, adaptando-se a regras e imposições de atores keystone (empresas centrais). Para possibilitar a compreensão da formação e funcionamento do ECOS, o trabalho propôs e testou um framework, baseado na literatura, que permitiu essa caracterização de forma abrangente. Para abordar tais questões, foi usada a metodologia de estudo de casos múltiplos na análise de empresas parceiras que atuam em grandes ECOS presentes no Brasil. Foram constatadas diversas adaptações nos aspectos de negócio e sociais dos parceiros, como adoção de modelo de negócios específicos e adaptações nas equipes. A profundidade dessas adaptações depende do modelo e da forma de trabalho da keystone - havendo muita variação de um ECOS para outro. O framework teórico proposto para caracterização foi adequado e permitiu o entendimento de diversos aspectos dos ECOS estudados pela unificação de outros frameworks e aspectos abordados por outros autores - e esse modelo é uma das principais contribuições deste trabalho. O confronto de algumas afirmações extraídas da bibliografia com casos reais foi outro ponto importante, contribuindo com a construção da teoria sobre o tema. / The software industry have been growing all over the world, including Brazil. A panorama of changes in software production is observed, with a growing trend of development in partnerships rather than the traditional model. In this new approach, called the Software Ecosystem (SECO), a company builds a community of developers around its core product to better meet the growing demands of its customers. The understanding of these changes and their impacts on companies operating in this sector in Brazil is important and is still maturing. Among the gaps are the creation of models to study and characterize SECO, as well as the study of their business, social and technical aspects. This work concentrates on the analysis of the first two aspects, focusing on how actors called niche players have to adapt to act according to the new approach, adapting to rules and impositions of keystones. To allow the understanding of SECOs formation and functioning, the work proposed and tested a framework, based on the literature, that allowed this characterization comprehensively. To address such issues, the multiple case study methodology was used in the analysis of niche players that operate in large ECOS present in Brazil. There were several adaptations in the business and social aspects of the partners, such as adoption of a specific business model and adaptations in the teams. The depth of these adaptations depends on the model and how the keystone works - there is a lot of variation from one SECO to another. The proposed theoretical framework for characterization was adequate and allowed the understanding of several aspects of studied cases by the unification of other frameworks and aspects addressed by other authors - and this framework is one of the main contributions of this work. The confrontation of some statements extracted from the bibliography with real cases was another important point, in the sense of having contributed with the construction of the theory on the subject.

The concept of the ecotone was formalised by Clements (1 905) as a boundary zone between plant communities. Little research exists on the ecological importance or the geographical variability of these zones. Two types of boundaries are acknowledged: the ecotone and the ecocline. The ecotone is a sharp boundary; the ecocline a gradual boundary. The term 'transitional area' is proposed here to more accurately describe these areas as this research demonstrates that a complex continuum exists between the two end points. Additionally, mosaics often complicate the nature of the transition and may form a boundary type in their own right. Upland plant communities represent important semi-natural habitats within the British Isles. Effective management depends on an understanding of their structure and function. This research is primarily concerned with the description of structure (spatial pattern and variability in floristic composition) but explanation of these patterns is only possible through an understanding of function (vegetation dynamics). Pilot studies determined an appropriate methodology for studying transitional areas. The approach progressed from a linear transect to a two-dimensional rectangular transect. The pilot studies also evaluated a range of methods for data analysis. Extended field sampling followed which included 23 sites in 4 locations: Dartmoor, Snowdonia, North York Moors and Barra, Western Isles of Scotland. Data analysis exposed the complexities of the transitional areas sampled but 'noise' often obscured the true characteristics. To overcome this a Species Ratio Index Model was devised to identify the strength of signal for each boundary. The final characterisation of transitional areas is based on three main components: ecotone, ecocline and mosaics, each displaying varying amplitude. Of the sites sampled, few boundaries revealed single characteristics and the majority were far more complex than their observed patterns implied. On the basis of this characterisation a classification is proposed which incorporates both natural and anthropogenic factors. The classification represents an important contribution to the understanding of boundary types. This study reinforces the significance of boundaries in the landscape. The potential for future research is great, particularly through the development of a predictive model for management purposes.

O setor de software e seu uso vêm crescendo em todo o mundo, incluindo o Brasil. Observa-se um panorama de mudanças na produção de software, com tendência crescente de desenvolvimento em parcerias em vez do modelo tradicional. Nessa nova abordagem, chamada de Ecossistema de Software (ECOS), uma empresa constrói uma comunidade de desenvolvedores ao redor de seu produto principal para atender melhor às crescentes demandas de seus clientes. O entendimento dessas mudanças e seus impactos nas empresas atuantes nesse setor no Brasil é importante e ainda se encontra em maturação Entre as lacunas estão a criação de modelos para estudo e caracterização de ECOS, além do estudo de seus aspectos de negócio, sociais e técnicos. Este trabalho concentrou-se na análise dos dois primeiros aspectos, com foco em como atores chamados niche players (ou parceiros) têm que se adaptar para atuar de acordo com a nova abordagem, adaptando-se a regras e imposições de atores keystone (empresas centrais). Para possibilitar a compreensão da formação e funcionamento do ECOS, o trabalho propôs e testou um framework, baseado na literatura, que permitiu essa caracterização de forma abrangente. Para abordar tais questões, foi usada a metodologia de estudo de casos múltiplos na análise de empresas parceiras que atuam em grandes ECOS presentes no Brasil. Foram constatadas diversas adaptações nos aspectos de negócio e sociais dos parceiros, como adoção de modelo de negócios específicos e adaptações nas equipes. A profundidade dessas adaptações depende do modelo e da forma de trabalho da keystone - havendo muita variação de um ECOS para outro. O framework teórico proposto para caracterização foi adequado e permitiu o entendimento de diversos aspectos dos ECOS estudados pela unificação de outros frameworks e aspectos abordados por outros autores - e esse modelo é uma das principais contribuições deste trabalho. O confronto de algumas afirmações extraídas da bibliografia com casos reais foi outro ponto importante, contribuindo com a construção da teoria sobre o tema. / The software industry have been growing all over the world, including Brazil. A panorama of changes in software production is observed, with a growing trend of development in partnerships rather than the traditional model. In this new approach, called the Software Ecosystem (SECO), a company builds a community of developers around its core product to better meet the growing demands of its customers. The understanding of these changes and their impacts on companies operating in this sector in Brazil is important and is still maturing. Among the gaps are the creation of models to study and characterize SECO, as well as the study of their business, social and technical aspects. This work concentrates on the analysis of the first two aspects, focusing on how actors called niche players have to adapt to act according to the new approach, adapting to rules and impositions of keystones. To allow the understanding of SECOs formation and functioning, the work proposed and tested a framework, based on the literature, that allowed this characterization comprehensively. To address such issues, the multiple case study methodology was used in the analysis of niche players that operate in large ECOS present in Brazil. There were several adaptations in the business and social aspects of the partners, such as adoption of a specific business model and adaptations in the teams. The depth of these adaptations depends on the model and how the keystone works - there is a lot of variation from one SECO to another. The proposed theoretical framework for characterization was adequate and allowed the understanding of several aspects of studied cases by the unification of other frameworks and aspects addressed by other authors - and this framework is one of the main contributions of this work. The confrontation of some statements extracted from the bibliography with real cases was another important point, in the sense of having contributed with the construction of the theory on the subject.

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No description available.