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- Bjursten, Henrik, et al.
(författare)
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Increased long-term mortality with plasma transfusion after coronary artery bypass surgery.
- 2013
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Ingår i: Intensive Care Medicine. - : Springer Science and Business Media LLC. - 0342-4642 .- 1432-1238. ; 39:3, s. 437-444
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Patients undergoing cardiac surgery often require transfusions of red blood cells, plasma and platelets. These components differ widely in both indications for use and composition. However, from a statistical point of view there is a significant colinearity between the components. This study explores the relation between the transfusion of different blood components and long-term mortality. METHODS: A retrospective single-centre study was performed including 5,261 coronary artery bypass grafting patients, excluding patients receiving more than eight units of red blood cells, those suffering early death (7 days) and emergency cases. Patients were followed up for a period of up to 7.5 years. A broad spectrum of potential risk factors was analysed using Cox proportional hazards survival regression. Non-significant risk factors were removed by step-wise elimination, and transfusion of red blood cells, plasma and platelets was forced to remain in the model. RESULTS: The transfusion of red blood cells was not associated with decreased long-term mortality (HR = 1.007, p = 0.775), whereas the transfusion of plasma was associated with decreased long-term survival (HR = 1.060, p < 0.001), and the transfusion of platelets was associated with increased long-term survival (HR = 0.817, p = 0.011). The risk associated with transfusion of plasma was mainly attributed to patients receiving large amounts of plasma. All hazard ratios are per unit of blood product transfused. CONCLUSIONS: No association was found between the transfusion of red blood cells and mortality during the study period. However, transfusion of plasma was associated with increased mortality while transfusion of platelets was associated with decreased mortality during the study period.
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| 3. |
- Bjursten, Henrik
(författare)
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Invited commentary.
- 2006
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Ingår i: Annals of Thoracic Surgery. - : Elsevier BV. - 1552-6259 .- 0003-4975. ; 82:1, s. 56-56
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Fredholm, Susanne, 1978
(författare)
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Assets in the age of tourism: the development of heritage planning in Ghanaian policy
- 2016
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Ingår i: Journal for Contemporary African Studies. - : Informa UK Limited. - 0258-9001 .- 1469-9397. ; 34:4, s. 498-518
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Tidskriftsartikel (refereegranskat)abstract
- Heritage planning in Ghana is mainly governed by the idea of sustainable pro-poor tourism, but is only marginally integrated with general planning programmes and fragmentally addressed by policy-makers. Motivated by the general lack of research on heritage policy in Ghana, this paper examines the role of heritage planning in national socio-economic, cultural and tourism policy and highlights various ambiguities in terms of concepts, objectives and approaches. The major findings show gaps between rational and communicative planning ideals, between informal management systems and wider democratic concerns, and between delimited and comprehensive planning perspectives. The central argument is that the lack of coherence among different development planning perspectives is an issue that future heritage policy-making needs to consider in order to balance tourism development with concerns such as social stability, community development and local pride of place.
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| 7. |
- Lind Östlund, Johan
(författare)
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Dynamic soil-structure interaction of simply supported high-speed railway bridges
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Research performed on the subject of dynamic soil-structure interaction (SS) concerning railway bridges is presented in this thesis with the focus on simply supported railway bridges supported by shallow foundations in soil strata on bedrock. The research aims to obtain insight into the SSI of high-speed railway bridges and to provide recommendations on how to model the soil-bridge system from a design perspective.A three-dimensional (3D) simply supported soil-bridge model was first developed and the effects from model assumptions made on the soil-foundation system was evaluated in a 3D setting (paper I). The soil-foundation system was then refined and a model assumptions study was performed in order to evaluate the effects of model assumptions on impedance functions, including the influence of the permanent load acting on the soil-foundation system (paper II). Finally, a study of the assembled soil-bridge system was performed in an extensive parametric study including a set of 2D bridge models in combination with a set of shallow foundations in soil strata on bedrock (paper III). A supplementary section related to paper III was also added in this thesis, showing the effects of the substructure mass.The model assumptions made when creating the soil-foundation model and the soil-bridge model can be very important and must be made with care. The permanent load acting on the soil-foundation systems of shallow foundations may alter the impedance functions significantly. The substructure mass may alter the behavior of the soil-bridge system depending on its magnitude, and neglecting it gives inaccurate results. The 3D effects of SSI do not cause high vibrations due to modes other than the first bending mode, and assuming a 2D bridge model is generally acceptable.The effects of SSI on the soil-bridge systems with shallow soil strata are largely dependent on the ratio between the natural frequency of the bridge and the fundamental frequency of the soil. Depending on the value of this ratio, the effect of including SSI in bridge models may contribute to the bridge obtaining a negligible, conservative, or non-conservative response, as compared to the bridge with the assumption of non-flexible supports.
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| 8. |
- Lind Östlund, Johan, et al.
(författare)
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On the influence of shallow soil strata on the dynamic soil-structure interaction of simply supported high-speed railway bridges
- 2020
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Ingår i: International Journal of Rail transportation. - : Informa UK Limited. - 2324-8378 .- 2324-8386.
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Tidskriftsartikel (refereegranskat)abstract
- The influence of dynamic soil-structure interaction (SSI) on simply supported railway bridges is investigated. Impedance functions are calculated considering shallow foundations in soil strata limited by bedrock. The impedance functions are coupled to bridge models, and the assembled soil-bridge systems are investigated addressing the modal properties. A parametric study is performed on a large set of soil-bridge systems. Finally, the response to train loading is analysed. The study shows that the effects of SSI are essentially different depending on whether radiation damping is active or not. Shorter bridges are often affected by radiation damping and the response due to train loading may be significantly reduced when SSI is considered. However, for longer bridges (>15 m) the effect of SSI is often small. Due to the stiffness reduction of the impedance, some bridges may even have a detrimental effect from SSI and a reduction of the traffic speed is obtained.
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| 10. |
- Nilsson, Håkan, et al.
(författare)
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The Scalable Tree Protocol : A Cache Coherence Approach for Large-Scale Multiprocessors
- 1992
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Konferensbidrag (refereegranskat)abstract
- The problem of cache coherence in large-scale shared-memory multiprocessors has been addressed using directory-schemes. Two problems arise when the number of processors increases: the network latency increases and the implementation cost must be kept acceptable. The authors present a tree-based cache coherence protocol called the scalable tree protocol (STP). They show that it can be implemented at a reasonable implementation cost and that the write latency is logarithmic to the size of the sharing set. How to maintain an optimal tree structure and how to handle replacements efficiently are critical issues the authors address for this type of protocol. They compare the performance of the STP with that of the scalable coherent interface (SCI) (IEEE standard P1596) by considering a classical matrix-oriented algorithm targeted for large-scale parallel processing. They show that the STP manages to reduce the execution time considerably by reducing the write latency.
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