| 1. |
- Bengtsson, Anders K.H., et al.
(författare)
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Particles, superparticles and twistors
- 1987
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Ingår i: Phys. Rev. D36 (1987) 1766.
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Tidskriftsartikel (refereegranskat)abstract
- The covariant Green-Schwarz action for a superstring has never been quantized covariantly. The physics behind this is discussed. We then consider the corresponding point-particle action in four dimensions, and write down a master action from which it can be obtained as a gauge choice: the ‘‘space-time gauge.’’ There is also a ‘‘twistor gauge,’’ in which covariant quantization is straightforward (as noted previously by Shirafuji).
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| 2. |
- Bengtsson, Christine, et al.
(författare)
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Systemic lupus erythematosus and cardiac risk factors : medical record documentation and patient adherence
- 2011
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Ingår i: Lupus. - Houndmills, Basingstoke, Hampshire : Stockton. - 0961-2033 .- 1477-0962. ; 20:10, s. 1057-1062
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Tidskriftsartikel (refereegranskat)abstract
- This study explores patients' knowledge of cardiac risk factors (CRFs), analyses how information and advice about CRFs are documented in clinical practice, and assesses patient adherence to received instructions to decrease CRFs. Systemic lupus erythematosus (SLE) patients with >= 4 ACR criteria participated through completing a validated cardiovascular health questionnaire (CHQ). Kappa statistics were used to compare medical records with the self-reported CHQ (agreement) and to evaluate adherence. Two hundred and eleven (72%) of the known patients with SLE participated. The mean age of the patients was 55 years. More than 70% of the SLE patients considered hypertension, obesity, smoking and hypercholesterolaemia to be very important CRFs. The agreement between medical record documentation and patients' reports was moderate for hypertension, overweight and hypercholesterolaemia (kappa 0.42-0.60) but substantial for diabetes (kappa 0.66). Patients' self-reported adherence to advice they had received regarding medication was substantial to perfect (kappa 0.65-1.0). For lifestyle changes in patients with hypertension and overweight, adherence was only fair to moderate (kappa 0.13-0.47). Swedish SLE patients' awareness of traditional CRFs was good in this study. However, the agreement between patients' self-reports and medical record documentation of CRF profiles, and patients' adherence to medical advice to CRF profiles, could be improved. Lupus (2011) 20, 1057-1062.
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| 3. |
- Bengtsson, Anders K. H., et al.
(författare)
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Applications of eigenvector centrality to small social networks
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This article investigates conceptual and methodological questions that may arise in applying eigenvector centrality to small social networks such as school classes. The focus on small networks brings out surprising and subtle properties related to the interpretation of the measure. We investigate examples where the weighted adjacency matrix of the underlying social network quantifies inter-individual preferences of whom to work with or play with. We show that mathematical operations such as transposition and symmetrization of the weighted adjacency matrix enhances the power of the measure. It is demonstrated that it is not sufficient to work with the original weight matrix. By working with a symmetrized or a semi-symmetrized or a transposed weight matrix different characteristics of the social interaction are revealed. The method chosen depends on the purpose of the investigation. Identifying isolated or popular individuals in the network are also facilitated using these operations.
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| 4. |
- Bengtsson, Anders K.H., et al.
(författare)
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Uniqueness of superstring actions
- 1984
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Ingår i: Nucl.Phys.B254 (1985) 625.
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Tidskriftsartikel (refereegranskat)abstract
- We consider local counterterms to 4-dimensional gravity and 4- and 10-dimensional super-gravity theories in the light-front gauge. With the technique developed, we show that there are no local counterterms other than the lagrangian possible in the superstring thoeries. This is a strong indication that these theories are finite or at least renormalizable to allorders in the perturbation expansions.
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