| 1. |
- Anell, Anders, et al.
(författare)
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A randomized comparison between league tables and funnel plots as an aid to health care decision-making
- 2017
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Ingår i: International Journal for Quality in Health Care. - : Oxford University Press (OUP). - 1464-3677 .- 1353-4505. ; 28:6, s. 816-823
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Tidskriftsartikel (refereegranskat)abstract
- Objective Comparison of provider performance is commonly used to inform health care decision-making. Little attention has been paid to how data presentations influence decisions. This study analyzes differences in suggested actions by decision-makers informed by league tables or funnel plots.Design Decision-makers were invited to a survey and randomized to compare hospital performance using either league tables or funnel plots for four different measures within the area of cancer care. For each measure, decision-makers were asked to suggest actions towards 12–16 hospitals (no action, ask for more information, intervene) and provide feedback related to whether the information provided had been useful.Setting Swedish health care.Participants Two hundred and twenty-one decision-makers at administrative and clinical levels.Intervention Data presentations in the form of league tables or funnel plots.Main outcome measures Number of actions suggested by participants. Proportion of appropriate actions.Results For all four measures, decision-makers tended to suggest more actions based on the information provided in league tables compared to funnel plots (44% vs. 21%, P < 0.001). Actions were on average more appropriate for funnel plots. However, when using funnel plots, decision-makers more often missed to react even when appropriate.Conclusions The form of data presentation had an influence on decision-making. With league tables, decision-makers tended to suggest more actions compared to funnel plots. A difference in sensitivity and specificity conditioned by the form of presentation could also be identified, with different implications depending on the purpose of comparisons. Explanations and visualization aids are needed to support appropriate actions.
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| 2. |
- Fabian, Botond, et al.
(författare)
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Diagnostic challenges in patients with reninomas and extrarenal renin-producing tumours
- 2024
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Ingår i: Clinical Endocrinology. - 0300-0664 .- 1365-2265. ; 101:1, s. 3-9
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Forskningsöversikt (refereegranskat)abstract
- Renin-secreting tumours are rare causes of secondary hypertension and hypokalaemia. They are usually surgically curable, hence proper diagnostic work-up and tumour localisation is essential. In this paper, we present three Swedish patients recently diagnosed with renin secreting tumours, two with reninomas and one with an extrarenal renin-producing tumour, to illustrate diagnostic challenges. We also discuss the biochemical work-up, the pros and cons of different imaging techniques (computer tomography [CT], magnetic resonance imaging and [18F]fluorodeoxyglucose-positron emission tomography-CT), as well as how renal vein sampling (RVC) may contribute to localisation of the tumour.
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| 3. |
- Rydén, Oskar, et al.
(författare)
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Linking democracy and biodiversity conservation: Empirical evidence and research gaps
- 2020
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49, s. 419-433
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Tidskriftsartikel (refereegranskat)abstract
- Increasing human pressure threatens plant and animal species with extinction worldwide. National political institutions constitute an important arena for biodiversity conservation. Yet, the relationship between how democratic these national institutions are and a country’s efforts towards and track-record for biodiversity conservation remains poorly understood. In this review, we outline the theoretical links between democracy and biodiversity conservation and review the empirical literature testing them. While more studies reported a positive than a negative relation between democracy and biodiversity conservation (15 vs. 11), the most common result was a mixed relationship (28), often conditioned on economic factors. The use of different proxies to measure biodiversity, including deforestation, protected areas, threatened species, and fishery statistics emerged as a primary obstacle for synthesis. We suggest overcoming this caveat together with a consistent definition of democratic institutions and a standardized statistical framework as research priorities to improve policies against the global biodiversity loss. © 2019, The Author(s).
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| 4. |
- Sjodin, Andreas, et al.
(författare)
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UPSC-BASE - Populus transcriptomics online
- 2006
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Ingår i: The Plant Journal. - Oxford : Blackwell. - 0960-7412 .- 1365-313X. ; 48:5, s. 806-817
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Tidskriftsartikel (refereegranskat)abstract
- The increasing accessibility and use of microarrays in transcriptomics has accentuated the need for purpose-designed storage and analysis tools. Here we present UPSC-BASE, a database for analysis and storage of Populus DNA microarray data. A microarray analysis pipeline has also been established to allow consistent and efficient analysis (from small to large scale) of samples in various experimental designs. A range of optimized experimental protocols is provided for each step in generating the data. Within UPSC-BASE, researchers can perform standard and advanced microarray analysis procedures in a user-friendly environment. Background corrections, normalizations, quality-control tools, visualizations, hypothesis tests and export tools are provided without requirements for expert-level knowledge. Although the database has been developed primarily for handling Populus DNA microarrays, most of the tools are generic and can be used for other types of microarray. UPSC-BASE is also a repository of Populus microarray information, providing data from 21 experiments on a total of 407 microarray hybridizations in the public domain of the database. There are also an additional 10 experiments containing 347 hybridizations, where the automatically analysed data are searchable.
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| 5. |
- Tofeldt, Oskar, et al.
(författare)
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Guided wave evaluation techniques for testing of plate-like concrete structures
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is a growing need for non-destructive techniques capable of investigating civilengineering structures of concrete material. The Impact-Echo (IE) method is one suchtechnique based on the study of a resonant and stationary mode. This mode corresponds to a Lamb mode. In turn, this accentuates that the IE method can easily be extended to include the analysis of propagating Lamb modes as well. Thereby a quantitative evaluation of the elastic plate properties and thickness is possible. Moreover, the use of Lamb waves lay the foundations for extended analysis which makes measurements based on an extension of the IE method an attractive complement to current ultrasonic techniques for plate-like concrete structures.
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| 6. |
- Tofeldt, Oskar, et al.
(författare)
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Lamb Wave Phase Velocity Imaging of Concrete Plates with 2D Arrays
- 2017
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Ingår i: Journal of Nondestructive Evaluation. - : Springer Science and Business Media LLC. - 1573-4862 .- 0195-9298. ; 37:4
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Tidskriftsartikel (refereegranskat)abstract
- In the nondestructive evaluation of concrete structures, ultrasonic techniques are considered to be more capable than low-frequency techniques such as the impact-echo method. This is especially true with the recent development of ultrasonictransducers, synthetic apertures, and results in an image form, and because low-frequency techniques are usually limited intheir evaluation to the frequency of one single resonant mode. With the aim of reducing this gap in capabilities, we presenta 2D array and wide-frequency bandwidth technique for Lamb wave phase velocity imaging. The presentation involves ameasurement on a newly cast concrete plate using a hammer and an accelerometer as an example. The key concept of thetechnique is the use of 2D arrays that record a full wave field response over a limited surface subdomain within the completemeasurement domain. Through a discrete Fourier transform, a spectral estimate is obtained for the 2D array in the frequency-phase velocity domain. The variation of the phase velocity is then mapped using a stepwise movement of the 2D array withinthe complete measurement domain. With two different types of 2D arrays, the variation of the phase velocity for the A0Lamb mode is mapped and displayed in a polar and image plot, and low variation is observed for both cases. This resultverifies the expected condition of a homogenous material and plate thickness and, more importantly, highlights the potentialof wide-frequency bandwidth techniques based on full wave field data.
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| 7. |
- Tofeldt, Oskar, et al.
(författare)
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Near Field Effects and Estimation of Poisson's Ratio in Impact-Echo Thickness Testing
- 2015
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Ingår i: 41st Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE). - : AIP Publishing LLC. - 1551-7616 .- 0094-243X. - 9780735412927 ; 1650, s. 1415-1422
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Konferensbidrag (refereegranskat)abstract
- Based on the polarization and shape of the first symmetric Lamb mode at the zero-group velocity point (S1-ZGV), a novel approach for Impact-Echo thickness testing is proposed. In this new approach all three plate parameters (thickness, velocity and Poisson's ratio) are estimated from the same wave mode (S1-ZGV). A traditional approach based on a measurement of the longitudinal-and Rayleigh wave velocity along the surface is also studied, and is found to be influenced by near field effects leading to an underestimated thickness. In addition, an alternative approach which estimates Poisson's ratio from the frequency ratio of the S1-ZGV and A2-ZGV point is discussed. The three studied approaches are demonstrated in a realistic field case.
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| 8. |
- Tofeldt, Oskar, et al.
(författare)
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Poisson's ratio from polarization of acoustic zero-group velocity Lamb mode.
- 2015
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Ingår i: The Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 138:1
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Tidskriftsartikel (refereegranskat)abstract
- Poisson's ratio of an isotropic and free elastic plate is estimated from the polarization of the first symmetric acoustic zero-group velocity Lamb mode. This polarization is interpreted as the ratio of the absolute amplitudes of the surface normal and surface in-plane components of the acoustic mode. Results from the evaluation of simulated datasets indicate that the presented relation, which links the polarization and Poisson's ratio, can be extended to incorporate plates with material damping. Furthermore, the proposed application of the polarization is demonstrated in a practical field case, where an increased accuracy of estimated nominal thickness is obtained.
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| 9. |
- Tofeldt, Oskar, et al.
(författare)
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Systematic errors in Impact-Echo thickness estimation due to near field effects
- 2015
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Ingår i: NDT & E International. - : Elsevier BV. - 0963-8695. ; 69, s. 16-27
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Tidskriftsartikel (refereegranskat)abstract
- Near field effects are found to create systematic errors, within the range of about 5-15%, in thickness estimations from Impact-Echo (IE) testing. This paper studies near field effects from a point source in a combined Multichannel Analysis of Surface Waves (MASW) and Impact-Echo analysis. The near field creates deviations in the measured velocity of the P-wave and the Rayleigh-wave, which lead to an underestimated thickness. This systematic error is identified in both a numerical and a real field case. The results are also compared with the conventional Impact-Echo method. (C) 2014 The Authors. Published by Elsevier Ltd.
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| 10. |
- Tofeldt, Oskar, et al.
(författare)
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Zero-group velocity modes in plates with continuous material variation through the thickness
- 2017
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 141:5
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Tidskriftsartikel (refereegranskat)abstract
- Lamb modes with zero group velocity at nonzero wave numbers correspond to local and stationary resonances in isotropic plates. Lamb modes can be utilized for nondestructive evaluation of the elastic properties and thickness. One example of an application is the testing of plate-like concrete structures. In this example, continuous variation in the material velocity through the thickness may occur. This is usually not accounted for in analyses, and with this as starting point, two inhomogeneous and nonsymmetric cases with continuous material variations are investigated using a semi-analytical finite element technique and a simulated measurement application. In a numerical study limited to the lowest zero-group velocity mode, results show that these modes for the inhomogeneous cases are generated with similar behavior and the same detectability as in the case of an isotropic plate. However, a complex relationship between mode frequency and material velocity exists for the inhomogeneous cases. This hinders the evaluation and interpretation of representative estimations such as those for a cross-sectional mean value of the plate properties. This may lead to errors or uncertainties in practical applications.
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