| 1. |
- Eriksson, Sara, 1974, et al.
(författare)
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Indicators of petroleum hydrocarbon biodegradation in anaerobic granitic groundwater
- 2006
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Ingår i: Geomicrobiology Journal. - : Informa UK Limited. - 0149-0451 .- 1521-0529. ; 23:1, s. 45-58
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to find indicators of petroleum biodegradation in granitic groundwater. Both pristine and contaminated groundwaters from boreholes around petroleum storage vaults located approximately 40 m below the surface in granite and with storage capacities of up to 120,000 m(3) were sampled. Total numbers of microorganisms, "most probable numbers" (MPN) of anaerobic bacteria, and chemical indications of microbial activity were determined in the groundwater. Hydrocarbon contaminants and metabolites were detected using gas chromatographymass spectrometry (GC-MS). In contaminated groundwater, the total number of microorganisms was 2-4 x 10(6) ml(-1), which was significantly higher than the 6 x 10(4) ml(-1) found in pristine groundwater. This microbial abundance was also reflected in the MPN analysis. Up to 7 x 10(4) nitrate-, 2 x 10(3) iron-, and 3 x 10(4) sulfate-reducing bacteria were detected in contaminated groundwaters. In such groundwaters, depletion of anaerobic electron acceptors and detection of reduced species could be established. We also proposed using a high alkalinity/hardness of water quota (A/H quota) as an indicator of microbial activity. In contaminated groundwaters the A/H quota averaged 2.8, while in pristine groundwater the same was only 1.3. Moreover, the presence of 20 oxidized petroleum hydrocarbons, i.e., putative metabolites of which 9 were strictly intracellular, was detected in the contaminated groundwaters. Phylogenetic neighbor-joining analysis of 16S rRNA genes provided information about the bacterial communities. The bacteria in contaminated groundwater were found to be strikingly similar to bacteria in other hydrocarbon-contaminated environments.
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| 2. |
- Eriksson, Sara, 1974, et al.
(författare)
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Propylphenols are metabolites in the anaerobic biodegradation of propylbenzene under iron-reducing conditions
- 2005
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Ingår i: Biodegradation. - : Springer Science and Business Media LLC. - 1572-9729 .- 0923-9820. ; 16:3, s. 253-263
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Tidskriftsartikel (refereegranskat)abstract
- The metabolism of monoaromatic hydrocarbons by an iron-reducing bacterial enrichment culture originating from diesel-contaminated groundwater was examined using d 7 -propylbenzene as a model hydrocarbon. Sequence analysis of the 16S rDNA gene showed that the dominant part (10 of 10 clones) of the enrichment culture consisted of a bacterium closely related to clones found in benzene-contaminated groundwater and to the iron-reducing β- proteobacterium, Rhodoferax ferrireducens (similarity values were 99.5% and 98.3%, respectively). In degradation studies conducted over 18 weeks, d 7 -propylphenols were detected by gas chromatography-mass spectrometry (GC/MS) as intra-cellular metabolites concomitant with cell growth in the cultures. The amount of propylphenols increased during the exponential growth phase, and by the end of this phase 4 × 10 -14 moles of ferric iron were reduced and 3 × 10 -15 moles propylphenol produced for every cell formed. During the stationary growth phase the cell density was approximately 10 7 ml -1 , with significantly correlated amounts of propylphenols. Succinate derivates of propylbenzene or phenylpropanol previously shown to be the initial metabolites in the anaerobic degradation of alkylbenzenes could not be identified. This study is the first to report that oxidation of propylbenzene to propylphenols can initiate anaerobic propylbenzene degradation and that iron-reducing bacteria are responsible for this process. In addition, the study shows the importance of taking account of the metabolites adhering to solid phases when determining the extent of biodegradation, so as not to underestimate the extent of the process.
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| 3. |
- Kihlén, Tobias, 1976-
(författare)
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Logistics-based Competition : A Business Model Approach
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Logistics is increasingly becoming recognised as a source of competitive advantage, both in practice and in academia. The possible strategic impact of logistics makes it important to gain deeper insight into the role of logistics in the strategy of the firm. There is however a considerable research gap between the quite abstract strategy theory and logistics research. A possible tool to use in bridging this gap is identified in business model research. Therefore, the purpose of this dissertation is to describe and analyse logisticsbased competition using a business model approach, a topic not handled in earlier research. This purpose entails investigating the role of logistics in the strategy of the firm by identifying a number of business model components which together constitute a logistics-based business model.Theoretically, the dissertation departs from strategic management and more specifically from the two opposing strategy theoretical perspectives the resource-based view of the firm (RBV) and the industrial organisation school of thought (I/O). From this foundation, the theoretical framework is further built upon with logistics- and business model research leading to a model of analysis that eventually evolves into one of the main outcomes of the dissertation: a logistics-based business model.The methodology used is that of multiple case studies of largely qualitative character. The cases represent trading firms which all display long-term profitable growth, a consistency in their growth, and they all have a, by the management, outspoken focus on logistics. The cases have been analysed using a patternmatching approach.A key deliverable from this research is the logistics-based business model, a model consisting of five components: strategy, position, offering, activities and organisation, and resources. The logistics-based business model makes possible a description and analysis of the role of logistics in the strategy of the firm leading to the identification of specific characteristics of the business models of firms competing on logistics. A few of the results from this research are:● A logistics-based business model requires a synthesis of RBV and I/O.● Control over the logistics resources is a distinctive capability in a logistics-based business model.● Logistics strategy cannot be understood in terms of degree of integration only as much of the current logistics strategy research suggests.● Hybrid logistics-strategies can involve lean processes and agile assortment with standardisation as an enabler.● The domain of control of a logistics-based business model stretches beyond the domain of a traditional logistics strategy.● A single logistics-platform may support multiple offerings.For managers, the logistics-based business model is possible to use as a tool in business development.
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| 4. |
- Kihlén, Tobias, 1976-
(författare)
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On Logistics in the Strategy of the Firm
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to describe and analyse the role of logistics in the strategy of the firm. Leading to this purpose are empirical observations of firms that manage to grow under sustained profitability, by the means of logistics.The clothing retailers H&M and Inditex manage to pursue strategies of growth under sustained profitability. Both H&M and Inditex acknowledge that logistics is used in achieving these strategic goals. The competitive environments are similar for the two retailers. However, the strategy content, i.e. the what of strategy, differs greatly between H&M and its Spanish competitor. H&M focuses on economies of scale in their operations to allow for low logistics costs and a cost-efficient geographical expansion. Inditex focuses on flexibility and speed, being able to quickly respond to changes in demand, which calls for a more agile logistics platform.From this background, two cases are studied as regards the role of logistics in the strategy. The case companies Ahlsell and Bergman & Beving, two wholesalers of industrial goods, display growth under sustained profitability and have an outspoken focus on logistics in their strategies. The cases are described in terms of the content and the context of logistics in the strategy of the firm. The content is the what of strategy whereas the context is the where of strategy. The context is further divided into inner and outer context, where inner context is the firm and outer context is its environment.The theoretical basis of this research is found in logistics and in strategy: Logistics research on the relation between logistics and strategy from a logistics perspective, and strategy theory ranging from the resource-based view of the firm, or the inside-out perspective, to positioning theory, or the outside-in perspective. A pattern-matching methodology is used to establish an appropriate description of the logistics content and context in the strategy of the firm. In the content-dimension, the opposing views of the resource-based view and positioning theory are tested on the cases. In the context-dimension, the cases and their environment are described with a stance taken in the contingency approach to the organisation of logistics.The research shows that the role of logistics in the strategy of the firms in the scope of this study is most appropriately described using a resource-based view of the firm. Further, the two firms under study serve as examples of two different ways to use logistics in the strategy:- Bergman & Beving manages to integrate a decentralised group of product companies in one logistics platform.- Ahlsell achieves synergies in acquisitions by moving logistics and administration of the acquired firms into their centralised logistics platform.The cases also serve as examples of that the logistics solutions need not be optimal in terms of the lowest cost and the highest service level to be used successfully in the strategy of the firm to reach growth under sustained profitability. The firms in the scope of this research act in similar outer contexts but interpret these contexts in different ways depending on their manner to use logistics in the strategy. The research shows that similar outer contexts can be approached successfully with strategies with different logistics content.The logistics organisations in the firms in the scope of this thesis display robustness towards changes in the outer context of the firm, i.e. the logistics organisations can encounter considerable changes in the environment without altering their position in the firm. It is concluded that in order to make the role of logistics in the strategy more comprehensible, a bridge between the abstract strategy theory and the role of logistics needs to be established. A possibility to attain this can be found in the application of a business model framework to the relation between logistics and strategy, which is suggested as an area for further research.
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