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| 3. |
- Ackerman, I. N., et al.
(författare)
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Substantial rise in the lifetime risk of primary total knee replacement surgery for osteoarthritis from 2003 to 2013: an international, population-level analysis
- 2017
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 25:4, s. 455-461
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To estimate and compare the lifetime risk of total knee replacement surgery (TKR) for osteoarthritis (OA) between countries, and over time. Method: Data on primary TKR procedures performed for OA in 2003 and 2013 were extracted from national arthroplasty registries in Australia, Denmark, Finland, Norway and Sweden. Life tables and population data were also obtained for each country. Lifetime risk of TKR was calculated for 2003 and 2013 using registry, life table and population data. Results: Marked international variation in lifetime risk of TKR was evident, with females consistently demonstrating the greatest risk. In 2013, Finland had the highest lifetime risk for females (22.8%, 95% CI 22.5-23.1%) and Australia had the highest risk for males (15.4%, 95% CI 15.1-15.6%). Norway had the lowest lifetime risk for females (9.7%, 95% CI 9.5-9.9%) and males (5.8%, 95% CI 5.6-5.9%) in 2013. All countries showed a significant rise in lifetime risk of TKR for both sexes over the 10-year study period, with the largest increases observed in Australia (females: from 13.6% to 21.1%; males: from 9.8% to 15.4%). Conclusions: Using population-based data, this study identified significant increases in the lifetime risk of TKR in all five countries from 2003 to 2013. Lifetime risk of TKR was as high as 1 in 5 women in Finland, and 1 in 7 males in Australia. These risk estimates quantify the healthcare resource burden of knee OA at the population level, providing an important resource for public health policy development and healthcare planning. (C) 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
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- Finnveden, G., et al.
(författare)
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Evaluation of integration of sustainable development in higher education in Sweden
- 2020
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Ingår i: International Journal of Sustainability in Higher Education. - : Emerald. - 1467-6370. ; 21:4, s. 685-698
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Since 2006, higher education institutions (HEIs) in Sweden, should according to the Higher Education Act, promote sustainable development (SD). In 2016, the Swedish Government asked the Swedish higher education authority to evaluate how this study is proceeding. The authority chose to focus on education. This paper aims to produce a report on this evaluation. Design/methodology/approach All 47 HEIs in Sweden were asked to write a self-evaluation report based on certain evaluation criteria. A panel was appointed consisting of academics and representatives for students and working life. The panel wrote an evaluation of each HEI, a report on general findings and recommendations, and gave an overall judgement of each HEI in two classes as follows: the HEI has well-developed processes for integration of SD in education or the HEI needs to develop their processes. Findings Overall, a mixed picture developed. Most HEIs could give examples of programmes or courses where SD was integrated. However, less than half of the HEIs had overarching goals for integration of SD in education or had a systematic follow-up of these goals. Even fewer worked specifically with pedagogy and didactics, teaching and learning methods and environments, sustainability competences or other characters of education for SD. Overall, only 12 out of 47 got a higher judgement. Originality/value This is a unique study in which all HEIs in a country are evaluated. This provides unique possibilities for identifying success factors and barriers. The importance of the leadership of the HEIs became clear.
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- Koene, E., et al.
(författare)
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Eliminating time dispersion from visco-elastic simulations with memory variables
- 2019
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Ingår i: 81st EAGE Conference and Exhibition 2019. - : European Association of Geoscientists & Engineers. - 9789462822894 ; 2019, s. 1-5
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Konferensbidrag (refereegranskat)abstract
- In recent years, it has been recognized that the seismic wave equation solved with a finite-difference method in time causes a predictable and removable error through the use of so-called time-dispersion transforms. These transforms were thought not to apply to visco-elastic media. However, in this paper we demonstrate that the time-dispersion transforms remain applicable when the visco-elastic wave equation is solved with memory variables, as is commonly done. The crucial insight is that both the wave equation and the memory variables are computed with the same time-dispersion error. We show how the time-dispersion transforms can be implemented in, for example, MATLAB, and demonstrate the developed theory on a visco-elastic version of the Marmousi model. Then, the time-dispersion transforms allow computation of the visco-elastic wave equation with large steps in time without significant loss of accuracy, and without having to make any modifications to the model.
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| 7. |
- Koene, E F M, et al.
(författare)
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Finite-difference modelling of 2-D wave propagation in the vicinity of dipping interfaces : a comparison of anti-aliasing and equivalent medium approaches
- 2022
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Ingår i: Geophysical Journal International. - : Oxford University Press (OUP). - 0956-540X .- 1365-246X. ; 229:1, s. 70-96
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Tidskriftsartikel (refereegranskat)abstract
- Finite-difference (FD) modelling of seismic waves in the vicinity of dipping interfaces gives rise to artefacts. Examples are phase and amplitude errors, as well as staircase diffractions. Such errors can be reduced in two general ways. In the first approach, the interface can be anti-aliased (i.e. with an anti-aliased step-function, or a lowpass filter). Alternatively, the interface may be replaced with an equivalent medium (i.e. using Schoenberg & Muir (SM) calculus or orthorhombic averaging). We test these strategies in acoustic, elastic isotropic, and elastic anisotropic settings. Computed FD solutions are compared to analytical solutions. We find that in acoustic media, anti-aliasing methods lead to the smallest errors. Conversely, in elastic media, the SM calculus provides the best accuracy. The downside of the SM calculus is that it requires an anisotropic FD solver even to model an interface between two isotropic materials. As a result, the computational cost increases compared to when using isotropic FD solvers. However, since coarser grid spacings can be used to represent the dipping interfaces, the two effects (an expensive FD solver on a coarser FD grid) equal out. Hence, the SM calculus can provide an efficient means to reduce errors, also in elastic isotropic media.
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| 8. |
- Lefeber, E., et al.
(författare)
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Linear Controllers for Exponential Tracking of Systems in Chained Form
- 2000
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Ingår i: International Journal of Robust and Nonlinear Control. - 1099-1239. ; 10:4, s. 243-264
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we address the tracking problem for a class of non-holonomic chained-form control systems. We present a simple solution for both the state feedback and the dynamic output feedback problem. The proposed controllers are linear and render the tracking error dynamics globally ?-exponentially stable. We also deal with both control problems under input saturation. Application of the results to the control of wheeled mobile robots is illustrated by means of simulations of a car pulling a single trailer.
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| 9. |
- Lewis, Peter L., et al.
(författare)
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Impact of patient and prosthesis characteristics on common reasons for total knee replacement revision : a registry study of 36,626 revision cases from Australia, Sweden, and USA
- 2022
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 93, s. 623-633
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose — Total knee replacement (TKR) studies usually analyze all-cause revision when con-sidering relationships with patient and prosthesis factors. We studied how these factors impact different revision diagnoses. Patients and methods — We used data from 2003 to 2019 of TKR for osteoarthritis from the arthroplasty regis-tries of Sweden, Australia, and Kaiser Permanente, USA to study patient and prosthesis characteristics for specific revision diagnoses. There were 1,072,924 primary TKR included and 36,626 were revised. Factors studied included age, sex, prosthesis constraint, fixation method, bearing mobility, polyethylene type, and patellar component use. Revision diagnoses were arthrofibrosis, fracture, infection, instabil-ity, loosening, pain, patellar reasons, and wear. Odds ratios (ORs) for revision were estimated and summary effects were calculated using a meta-analytic approach. Results — We found between-registry consistency in 15 factor/reason analyses. Risk factors for revision for arthro-fibrosis were age <65 years (OR 2.0; 95% CI 1.4–2.7) and mobile bearing designs (MB) (OR 1.7; CI 1.1–2.5), for fracture were female sex (OR 3.2; CI 2.2–4.8), age ≥ 65 years (OR 2.8; CI 1.9–4) and posterior stabilized prostheses (PS) (OR 2.1; CI 1.3–3.5), for infection were male sex (OR 1.9; CI 1.7–2.0) and PS (OR 1.5; CI 1.2–1.8), for instability were age <65 years (OR 1.5; CI 1.3–1.8) and MB (OR 1.5; CI 1.1–2.2), for loosening were PS (OR 1.5; CI 1.4–1.6), MB (OR 2.2; CI 1.6–3.0) and use of ultra-high molecular weight polyethylene (OR 2.3; CI 1.8–2.9), for patellar reasons were not resurfacing the patella (OR 13.6; CI 2.1–87.2) and MB (OR 2.0; CI 1.2–3.3) and for wear was cementless fixation (OR 4.9; CI 4.3–5.5). Interpretation — Patients could be counselled regarding specific age and sex risks. Use of minimally stabilized, fixed bearing, cemented prostheses, and patellar components is encouraged to minimize revision risk.
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| 10. |
- Lewis, Peter L., et al.
(författare)
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Increases in the rates of primary and revision knee replacement are reducing : a 15-year registry study across 3 continents
- 2020
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 91:4, s. 414-419
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose — Rates of knee replacement (KR) are increasing worldwide. Based on population and practice changes, there are forecasts of a further exponential increase in primary knee replacement through to 2030, and a corresponding increase in revision knee replacement. We used registry data to document changes in KR over the past 15 years, comparing practice changes across Sweden, Australia, and the United States. This may improve accuracy of future predictions. Patients and methods — Aggregated data from the Swedish Knee Arthroplasty Register (SKAR), the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), and the Kaiser Permanente Joint Replacement Registry (KPJRR) were used to compare surgical volume of primary and revision KR from 2003 to 2017. Incidence was calculated using population census statistics from Statistics Sweden and the Australian Bureau of Statistics, as well as the yearly active membership numbers from Kaiser Permanente. Further analysis of KR by age < 65 and ≥ 65 years was carried out. Results — All registries recorded an increase in primary and revision KR, with a greater increase seen in the KPJRR. The rate of increase slowed during the study period. In Sweden and Australia, there was a smaller increase in revision surgery compared with primary procedures. There was consistency in the mean age at surgery, with a steady small decrease in the proportion of women having primary KR. The incidence of KR in the younger age group remained low in all 3 registries, but the proportional increases were greater than those seen in the ≥ 65 years of age group. Interpretation — There has been a generalized deceleration in the rate of increase of primary and revision KR. While there are regional differences in KR incidence, and rates of change, the rate of increase does not seem to be as great as previously predicted.
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