| 1. |
- Larsson, Magnus R., et al.
(författare)
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The stability of alexithymia during work in a high-stress environment : A prospective study of Swedish peacekeepers serving in Kosovo
- 2010
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Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 0036-5564 .- 1467-9450. ; 51:4, s. 350-355
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Tidskriftsartikel (refereegranskat)abstract
- We applied a prospective design to reinvestigate the issue whether the sub-domains of alexithymia could be considered stable traits or distress-related states. Assessments of alexithymia and subjective distress were conducted before deployment to Kosovo in a sample of male peacekeepers. A second assessment was conducted approximately six months later during the final phase of service. The results showed evidence of moderate to high relative stability in all alexithymic sub-domains. It was also found that a relative change in subjective distress predicted a relative change in difficulty identifying feelings and difficulty describing feelings but not in externally oriented thinking. We suggest therefore that the alexithymic sub-domains could be considered relatively stable traits but that the level of difficulty identifying and describing feeling varies with the level of subjective distress.
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| 2. |
- Lundh, Magnus, et al.
(författare)
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Model optimization for autotuners in industrial control systems
- 2021
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Ingår i: Proceedings of the 26th International Conference on Emerging Technologies and Factory Automation (ETFA). - 9781728129891 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Automatic tuning of PID controllers using relay feedback experiments has received attention on and off since it was first proposed and industrially implemented in a control system in the 1980s. While optimal experiment design and modern system identification easily outperform the original automatic tuner, they rely on computational resources that are not always available in industrial control systems. Here we present a combination of experiment and subsequent output-error identification of continuoustime first-order time-delayed (FOTD) system models, that requires very little in terms of computations and memory. The method has been extensively evaluated in simulation, and a prototype has been implemented for the ABB AC 800M controller family.
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| 3. |
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| 4. |
- Almén, Anja, et al.
(författare)
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Challenges assessing radiation risk in image-guided treatments-implications on optimisation of radiological protection
- 2018
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 38:3, s. 1064-1076
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Tidskriftsartikel (refereegranskat)abstract
- The present work explores challenges when assessing organ dose and effective dose concerning image-guided treatments. During these treatments considerable x-ray imaging is employed using technically advanced angiographic x-ray equipment. Thus, the radiation dose to organs and the related radiation risk are relatively difficult to assess. This has implications on the optimisation process, in which assessing radiation dose is one important part. In this study, endovascular aortic repair treatments were investigated. Organ dose and effective dose were assessed using Monte Carlo calculations together with a detailed specification of the exposure situation and patient size. The resulting normalised organ dose and effective dose with respect to kerma-area product for patient sizes and radiation qualities representative for the patient group were evaluated. The variability and uncertainty were investigated and their possible impact on optimisation of radiation protection was discussed. Exposure parameters, source to detector distances etc varied between treatments and also varied between image acquisitions during one treatment. Thus the derived normalised organ dose and effective dose exhibited a large range of values depending greatly on used exposure parameters and patient configuration. The derived normalised values for effective dose varied approximately between 0.05 and 0.30 mSv per Gy.cm(2) when taking patient sizes and exposure parameters into consideration, the values for organ doses exhibited even larger variation. The study shows a possible systematic error for derived organ doses and effective dose up to a factor of 7 if detailed exposure or patient characteristics are not known and/or not taken into consideration. The intra-treatment variability was also substantial and the normalised dose values varied up to a factor of 2 between image acquisitions during one treatment. The study shows that the use of conversion factors that are not adapted to the clinic can cause the radiation dose to be exaggerated or underestimated considerably. A conclusion from the present study is that the systematic error could be large and should be estimated together with random errors. A large uncertainty makes it difficult to detect true differences in radiation dose between methods and technology-a prerequisite for optimising radiation protection for image-guided treatments.
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| 5. |
- Almén, Anja, 1964, et al.
(författare)
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OPTIMISATION OF OCCUPATIONAL RADIATION PROTECTION IN IMAGE-GUIDED INTERVENTIONS: EXPLORING VIDEO RECORDINGS AS A TOOL IN THE PROCESS
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 425-429
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Tidskriftsartikel (refereegranskat)abstract
- The overall purpose of this work was to explore how video recordings can contribute to the process of optimising occupational radiation protection in image-guided interventions. Video-recorded material from two image-guided interventions was produced and used to investigate to what extent it is conceivable to observe and assess dose-affecting actions in video recordings. Using the recorded material, it was to some extent possible to connect the choice of imaging techniques to the medical events during the procedure and, to a less extent, to connect these technical and medical issues to the occupational exposure. It was possible to identify a relationship between occupational exposure level to staff and positioning and use of shielding. However, detailed values of the dose rates were not possible to observe on the recordings, and the change in occupational exposure level from adjustments of exposure settings was not possible to identify. In conclusion, the use of video recordings is a promising tool to identify dose-affecting instances, allowing for a deeper knowledge of the interdependency between the management of the medical procedure, the applied imaging technology and the occupational exposure level. However, for a full information about the dose-affecting actions, the equipment used and the recording settings have to be thoroughly planned.
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| 6. |
- Almén, Anja, 1964, et al.
(författare)
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Optimisation of occupational radiological protection in image-guided interventions: potential impact of dose rate measurements.
- 2015
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 35:1, s. 47-62
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Tidskriftsartikel (refereegranskat)abstract
- The optimisation of occupational radiological protection is challenging and a variety of factors have to be considered. Physicians performing image-guided interventions are working in an environment with one of the highest radiation risk levels in healthcare. Appropriate knowledge about the radiation environment is a prerequisite for conducting the optimisation process. Information about the dose rate variation during the interventions could provide valuable input to this process. The overall purpose of this study was to explore the prerequisite and feasibility to measure dose rate in scattered radiation and to assess the usefulness of such data in the optimisation process.Using an active dosimeter system, the dose rate in the unshielded scattered radiation field was measured in a fixed point close to the patient undergoing an image-guided intervention. The measurements were performed with a time resolution of one second and the dose rate data was continuously timed in a data log. In two treatment rooms, data was collected during a 6month time period, resulting in data from 380 image-guided interventions and vascular treatments in the abdomen, arms and legs. These procedures were categorised into eight types according to the purpose of the treatment and the anatomical region involved.The dose rate varied substantially between treatment types, both regarding the levels and the distribution during the procedure. The maximum dose rate for different types of interventions varied typically between 5 and 100mSvh(-1), but substantially higher and lower dose rates were also registered. The average dose rate during a complete procedure was however substantially lower and varied typically between 0.05 and 1mSvh(-1). An analysis of the distribution disclosed that for a large part of the treatment types, the major amount of the total accumulated dose for a procedure was delivered in less than 10% of the exposure time and in less than 1% of the total procedure time.The present study shows that systematic dose rate measurements are feasible. Such measurements can be used to give a general indication of the exposure level to the staff and could serve as a first risk assessment tool when introducing new treatment types or x-ray equipment in the clinic. For example, it could provide an indication for when detailed eye dose measurements are needed. It also gives input to risk management considerations and the development of efficient routines for other radiological protection measures.
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| 7. |
- Bergkvist, Sara, et al.
(författare)
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Transition from a two-dimensional superfluid to a one-dimensional mott insulator
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 99:11, s. 110401-1-110401-5
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Tidskriftsartikel (refereegranskat)abstract
- A two-dimensional system of atoms in an anisotropic optical lattice is studied theoretically. If the system is finite in one direction, it is shown to exhibit a transition between a two-dimensional superfluid and a one-dimensional Mott insulating chain of superfluid tubes. Monte Carlo simulations are consistent with the expectation that the phase transition is of Kosterlitz-Thouless type. The effect of the transition on experimental time-of-flight images is discussed.
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| 8. |
- Bergquist, Magnus, 1960, et al.
(författare)
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Practising Peer Review in Organizations: a Qualifier for Knowledge Dissemination and Legitimization
- 2001
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Ingår i: Journal of Information Technology. - London : SAGE Publications. ; 16:2, s. 99-112
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Tidskriftsartikel (refereegranskat)abstract
- A key issue in many organizations is how to disseminate information in an effective way and, more importantly, how to make use of this information in order to create new knowledge. One way of addressing this problem is to focus on how information is socially transformed into knowledge. This includes how knowledge is handled in practice and how the knowledge produced is quali ed as being something worth knowing and acting upon. Two well-established practices for doing this are the refereeing system and the peer review process. These are used in scienti c communities as a means of validating and legitimating knowledge, for example by reviewing journal papers before publishing or project proposals before granting funds, etc. This paper argues that peer review is a useful concept when looking at knowledge creation and legitimization in organizations. The social meaning of peer review is to legitimize new knowledge by organizationally sanctioning it and thereby creating a platform for collective sense making. This paper uses an example from a eld study in a pharmaceutical company in order to illustrate this argument. The study took place in a quality support department where the quality of health care products and processes was assessed. The organization had a need for fast and reliable updating of information that could in uence how the production process of pharmaceuticals should be carried out. In order to cope with these problems the department established an ‘evaluation loop’, which shared several characteristics with the peer review process.
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| 9. |
- Borges, A. H., et al.
(författare)
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Nonnucleoside Reverse-transcriptase Inhibitor- vs Ritonavir-boosted Protease Inhibitor-based Regimens for Initial Treatment of HIV Infection: A Systematic Review and Metaanalysis of Randomized Trials
- 2016
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 63:2, s. 268-280
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Tidskriftsartikel (refereegranskat)abstract
- Background. Previous studies suggest that nonnucleoside reverse-transcriptase inhibitors (NNRTIs) cause faster virologic suppression, while ritonavir-boosted protease inhibitors (PI/r) recover more CD4 cells. However, individual trials have not been powered to compare clinical outcomes. Methods. We searched databases to identify randomized trials that compared NNRTI-vs PI/r-based initial therapy. A meta-analysis calculated risk ratios (RRs) or mean differences (MDs), as appropriate. Primary outcome was death or progression to AIDS. Secondary outcomes were death, progression to AIDS, and treatment discontinuation. We calculated RR of virologic suppression and MD for an increase in CD4 cells at week 48. Results. We included 29 trials with 9047 participants. Death or progression to AIDS occurred in 226 participants in the NNRTI arm and in 221 in the PI/r arm (RR, 1.03; 95% confidence interval, .87-1.22; 12 trials; n = 3825), death in 205 participants in the NNRTI arm vs 198 in the PI/r arm (1.04; 0.86-1.25; 22 trials; n = 8311), and progression to AIDS in 140 participants in the NNRTI arm vs 144 in the PI/r arm (1.00; 0.80-1.25; 13 trials; n = 4740). Overall treatment discontinuation (1.12; 0.93-1.35; 24 trials; n = 8249) and from toxicity (1.21; 0.87-1.68; 21 trials; n = 6195) were comparable, but discontinuation due to virologic failure was more common with NNRTI (1.58; 0.91-2.74; 17 trials; n = 5371). At week 48, there was no difference between NNRTI and PI/r in virologic suppression (RR, 1.03; 0.98-1.09) or CD4(+) recovery (MD, -4.7 cells; -14.2 to 4.8). Conclusions. We found no difference in clinical and viro-immunologic outcomes between NNRTI-and PI/r-based therapy.
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