| 1. |
- Cornelissen, Johannes H C, et al.
(författare)
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Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes
- 2007
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 10:7, s. 619-627
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Tidskriftsartikel (refereegranskat)abstract
- Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide.Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.
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| 2. |
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| 3. |
- Ivanova, Elena P, et al.
(författare)
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Impact of Nanoscale Roughness of Titanium Thin Film Surfaces on Bacterial Retention
- 2010
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:3, s. 1973-1982
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Tidskriftsartikel (refereegranskat)abstract
- Two human pathogenic bacteria, Staphylococcus aureus CIP 68.5 and Pseudomonas aeruginosa ATCC 9025, were adsorbed onto surfaces containing Ti. thin films of varying thickness to determine the extent to which nanoscale surface roughness influences the extent of bacterial attachment. A magnetron sputter thin film system was used to deposit titanium films with thicknesses of 3,12, and 150 nm on glass substrata with corresponding surface roughness parameters of Rq 1.6, 1.2, and 0.7 nm (on a 4 μm x 4 μm scanning area). The chemical composition, wettability, and surface architecture of titanium thin films were characterized using X-ray photoelectron spectroscopy, contact angle measurements, atomic force microscopy, three-dimensional interactive visualization, and statistical approximation of the topographic profiles. Investigation of the dynamic evolution of the Ti. thin film, topographic parameters indicated that three commonly used parameters, Ra. Rq, and Rmax, were insufficient to effectively characterize the nanoscale rough/smooth surfaces. Two additional parameters, Rskw and Rkur: which describe the statistical distributions of roughness character, were found to be useful for evaluating the surface architecture. Analysis of bacterial retention profiles indicated that bacteria responded, differently to the surfaces on a scale of less than 1 nm change in the Ra and Rq Ti thin film surface roughness parameters by (i) an increased, number of retained cells by a factor of 2-3, and (ii) an elevated level of secretion of extracellular polymeric substances.
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| 4. |
- Wickramasinghe, Leelani Kumari, et al.
(författare)
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Agent-based intelligent collaborative care management
- 2009
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Ingår i: Proceedings of the Eighth International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2009). - 9780981738178 ; , s. 1387-1389
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Konferensbidrag (refereegranskat)abstract
- The aim of our research is to provide a unified model for the composition and management of consumer care services. We identify design, composition, distribution and management as key stages of this model and propose an Intelligent Collaborative Care Management (ICCM) System as its realisation. The distribution and management stages are implemented as multi-agent systems. Agents in the distribution stage carry out domain-specific negotiation and distribution processes for the assignment of tasks in the care plan. Through the agents in the management stage, we introduce the notion of 'failure prevention' and 'adherence support' in contrast to 'failure recovery' in planning. The key to failure prevention is to identify what has to be carried out to prevent care plan failures. The healthcare domain is used to demonstrate the ICCM system.
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| 5. |
- Wickramasinghe, Leelani Kumari, et al.
(författare)
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Goal-Directed Approach for Process Specification and Service Selection in Customer Life Cycle Management
- 2012
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Ingår i: Lecture Notes in Business Information Processing, Volume 98. - Berlin, Heidelberg : Springer. - 9783642285622 ; , s. 151-169
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Bokkapitel (refereegranskat)abstract
- Service selection is the first step in customer life cycle management where services are selected to meet a customer's goals or objectives, personalised to the circumstances of the customer. The aim of this paper is twofold: (1) to develop concepts and algorithms for goal-directed service selection; and (2) to compare and reconcile our goal-directed approach with a service-oriented approach. The proposed goal-directed service selection algorithm is based on a goal-directed domain description that represents the customer objectives and the business processes. We use service component architectures with formalised contractual service process definitions as a software engineering approach to architectural design and realisation of service-oriented architectures (SOA). The comparison aims to understand the relationship between and benefits of a goal-directed approach and a service oriented approach . We use case studies from two complex customer care management domains to demonstrate the concepts. The implemented algorithms are tested in a health care case study.
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