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| 2. |
- Ericsson, Åsa, et al.
(författare)
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Product-service systems - From customer needs to requirements in early development phases
- 2009
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Konferensbidrag (refereegranskat)abstract
- Framed by Product-Service Systems (PSS), this paper discuss how needs and requirements are applied in early phases. In product development literature these and closely related terms are mixed, and a focus on gathering customer information about goods and their use guides the development team. This theoretical study highlights that lifecycle commitments such as PSS insist on the generation of a broader information basis. The application of a divergent view on goods, their use and the customers is likely to provide such information basis. The discussion provides a proposal of a simple model to set needs and requirements in relation.
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| 3. |
- Laughlin, Ronald J, et al.
(författare)
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Effect of acetate on soil respiration, N2O emissions and gross N transformations related to fungi and bacteria in a grassland soil
- 2009
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Ingår i: Applied Soil Ecology. ; 42, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- Application of organic carbon to grassland in the form of manure or cattle slurry during the growing season is a normal agricultural practice. Under enhanced organic C supply changes in the grassland soil’s internal N cycling and in the microbial community are expected, in particular, the fungi–bacteria ratio. Here we present novel results from a 15N tracing study which aimed to investigate the role of fungi and bacteria in N transformations under enhanced organic C supply. We applied 15N labelled fertiliser to soil in a laboratory incubation with and without acetate addition. Moreover, we used specific microbial inhibitors to selectively inhibit either fungi or bacteria. The data from the incubation were used to calculate gross N transformation rates via 15N tracing models based on Monte Carlo sampling techniques. Our results show that fungi are the predominant organisms that carry out N transformations in a temperate grassland soil. Under enhanced organic C supply, the stimulation of the mineralization – immobilization – turnover and heterotrophic nitrification was predominantly related to fungal activity, indicating that fungi may play an increasingly important role in soils with an enhanced C supply. In addition, we showed that fungi were the dominant organisms for N2O production. Increased fungal activity under enhanced organic C supply may therefore increase N2O emissions from soil and have environmental consequences.
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| 6. |
- Rütting, Tobias, 1977, et al.
(författare)
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Functional role of DNRA and nitrite reduction in a pristine south Chilean Nothofagus forest
- 2008
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Ingår i: Biogeochemistry. ; 90:3, s. 243-258
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Tidskriftsartikel (refereegranskat)abstract
- Nitrite (NO2 −) is an intermediate in a variety of soil N cycling processes. However, NO2 − dynamics are often not included in studies that explore the N cycle in soil. Within the presented study, nitrite dynamics were investigated in a Nothofagus betuloides forest on an Andisol in southern Chile. We carried out a 15N tracing study with six 15N labeling treatments, including combinations of NO3 −, NH4 + and NO2 −. Gross N transformation rates were quantified with a 15N tracing model in combination with a Markov chain Monte Carlo optimization routine. Our results indicate the occurrence of functional links between (1) NH4 + oxidation, the main process for NO2 − production (nitritation), and NO2 − reduction, and (2) oxidation of soil organic N, the dominant NO3 − production process in this soil, and dissimilatory NO3 − reduction to NH4 + (DNRA). The production of NH4 + via DNRA was approximately ten times higher than direct mineralization from recalcitrant soil organic matter. Moreover, the rate of DNRA was several magnitudes higher than the rate of other NO3 − reducing processes, indicating that DNRA is able to outcompete denitrification, which is most likely not an important process in this ecosystem. These functional links are most likely adaptations of the microbial community to the prevailing pedo-climatic conditions of this Nothofagus ecosystem.
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| 7. |
- Rütting, Tobias, 1977, et al.
(författare)
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New insights on N transformations by 15N tracing techniques
- 2009
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Ingår i: Working Papers of the Finnish Forest Research Institute. - 1795-150X. - 9789514021763 ; 128
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Konferensbidrag (refereegranskat)abstract
- In recent years the understanding of the nitrogen (N) cycling in soil experienced great changes due to the discovery of a variety of new processes or underpinning the importance of alternative processes, including anaerobic ammonium oxidation (anammox), archaeal nitrification, fungal denitrification and co-denitrification, heterotrophic nitrification and nitrifier denitrification (Francis et al., 2007; Hayatsu et al., 2008). A widely used method to investigate N cycling are 15N tracing studies where one or more soil N pools are labelled with 15N and subsequently the concentrations and 15N enrichments are followed over a period of time. The main objective of these studies is to quantify the simultaneously occurring gross N transformations. Recent progress in 15N tracing models (Müller et al., 2007) enables us to perform more comprehensive process-specific analyses of the N cycle and investigate the ecological importance of previously ignored processes such as heterotrophic nitrification and dissimilatory nitrate reduction to ammonium (DNRA) (Rütting et al., 2008). Here we present results from several 15N labelling studies in temperate grassland and forest ecosystems from the northern and southern hemisphere. In these ecosystems DNRA is the dominant, sometimes exclusive pathway of NO3- consumption. The main advantage of DNRA over other NO3- consumption processes is that N is transferred into NH4+, another plant available N form, which is not prone to N losses. Therefore DNRA leads to conservation of mineral N in soils.
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| 9. |
- Staelens, Jeroen, et al.
(författare)
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Nitrogen dynamics in contrasting forest ecosystems exposed to enhanced atmospheric N deposition
- 2009
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Ingår i: Working Papers of the Finnish Forest Research Institute. - 1795-150X. - 9789514021763 ; 128
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Konferensbidrag (refereegranskat)abstract
- Despite chronically enhanced nitrogen (N) deposition to forest ecosystems in Europe and NE America, considerable N retention by forests has been observed. It is still unclear which factors determine N retention in forest soils. However, this knowledge is crucial to assess the impact of changing anthropogenic N emissions on future N cycling and N loss of forests. For coniferous and deciduous forest stands at comparable sites, it is known that both N deposition to the forest floor as well as N loss by leaching below the rooting zone are significantly higher in coniferous stands (De Schrijver et al., 2007). In addition, the N loss in coniferous stands is often more enhanced than can be explained by the higher N input only, which suggests lower N retention by coniferous stands and may be related to differences in litter quality, microbial activity, and N uptake by plant roots. To test this hypothesis, we studied the effect of forest type on N retention. N dynamics were examined for two adjacent forest stands (pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.)) on a well-drained soil type and with a similar stand history, which are located in a region with high N deposition (Belgium). Firstly, input-output N budgets were established by quantifying atmospheric deposition and leaching, which confirmed the above finding of higher N deposition and disproportionately higher N loss by the pine stand than the oak stand. Secondly, the fate of inorganic N within the ecosystems was studied by spraying dissolved 15N onto the forest floor, both as ammonium (NH4+) and nitrate (NO3-). The 15N recovery over time in organic and mineral soil layers, tree roots, water leaching, ferns, foliage, and stem wood was compared between the two forest stands and N treatments. Thirdly, in situ gross N transformation rates in undisturbed mineral forest soils were determined via a 15N tracing approach (Müller et al., 2007). Meaningful differences between the two forest stands were found for the rates of mineralisation, heterotrophic and autotrophic nitrification, and NH4+ and NO3- immobilisation. Unexpectedly, dissimilatory NO3- reduction to NH4+ (DNRA) was detected in the oak soil. This process has mainly been described for unpolluted soils (e.g., Huygens et al., 2008), and to the best of our knowledge, this is the first report of DNRA under field conditions in a temperate forest soil under high N deposition.
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