| 1. |
- Airila, M. I., et al.
(författare)
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Preliminary Monte Carlo simulation of beryllium migration during JET ITER-like wall divertor operation
- 2015
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 463, s. 800-804
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Tidskriftsartikel (refereegranskat)abstract
- Migration of beryllium into the divertor and deposition on tungsten in the final phase of the first ITER-like-wall campaign of JET are modelled with the 3D Monte Carlo impurity transport code ERO. The simulation covers the inner wall and the inner divertor. To generate the plasma background for Monte Carlo tracing of impurity particles, we use the EDGE2D/EIRENE code set. At the relevant regions of the wall, the estimated plasma conditions vary around T-e approximate to 5eV and n(e) 2 x 10(17) m(-3) (far-scrape-off layer; more than 10 cm away from the LCFS). We calculate impurity distributions in the plasma using the main chamber source as a free parameter in modelling and attempt to reproduce inter-ELM spectroscopic BeII line (527 nm) profiles at the divertor. The present model reproduces the level of emission close to the inner wall, but further work is needed to match also the measured emission peak values and ultimately link the modelled poloidal net deposition profiles of beryllium to post mortem data.
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| 2. |
- Baltag, Crina
(författare)
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Global Trends in Arbitration 2022
- 2022
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Ingår i: Stockholm Arbitration Yearbook 2022. - : Kluwer Law International. - 9789403518763 ; , s. 9-16
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Bokkapitel (refereegranskat)
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| 3. |
- Buckdahn, Rainer, et al.
(författare)
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A General Stochastic Maximum Principle for SDEs of Mean-field Type
- 2011
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Ingår i: Applied mathematics and optimization. - : Springer Science and Business Media LLC. - 0095-4616 .- 1432-0606. ; 64:2, s. 197-216
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Tidskriftsartikel (refereegranskat)abstract
- We study the optimal control for stochastic differential equations (SDEs) of mean-field type, in which the coefficients depend on the state of the solution process as well as of its expected value. Moreover, the cost functional is also of mean-field type. This makes the control problem time inconsistent in the sense that the Bellman optimality principle does not hold. For a general action space a Peng's-type stochastic maximum principle (Peng, S.: SIAM J. Control Optim. 2(4), 966-979, 1990) is derived, specifying the necessary conditions for optimality. This maximum principle differs from the classical one in the sense that here the first order adjoint equation turns out to be a linear mean-field backward SDE, while the second order adjoint equation remains the same as in Peng's stochastic maximum principle.
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| 4. |
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| 5. |
- Fong, Stephanie, et al.
(författare)
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Plastic changes in brain morphology in relation to learning and environmental enrichment in the guppy (Poecilia reticulata)
- 2019
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 222:10
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Tidskriftsartikel (refereegranskat)abstract
- Despite the common assumption that the brain is malleable to surrounding conditions mainly during ontogeny, plastic neural changes can occur also in adulthood. One of the driving forces responsible for alterations in brain morphology is increasing environmental complexity that may demand enhanced cognitive abilities (e.g. attention, memory and learning). However, studies looking at the relationship between brain morphology and learning are scarce. Here, we tested the effects of both learning and environmental enrichment on neural plasticity in guppies (Poecilia reticulata), by means of either a reversal-learning test or a spatial-learning test. Given considerable evidence supporting environmentally induced plastic alterations, two separate control groups that were not subjected to any cognitive test were included to account for potential changes induced by the experimental setup alone. We did not find any effect of learning on any of our brain measurements. However, we found strong evidence for an environmental effect, where fish given access to the spatial-learning environment had larger relative brain size and optic tectum size in relation to those exposed to the reversal-learning environment. Our results demonstrate the plasticity of the adult brain to respond adaptively mainly to environmental conditions, providing support for the environmental enhancement theory.
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| 6. |
- Herlitz, Johan, et al.
(författare)
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Ten year mortality in subsets of patients with an acute coronary syndrome
- 2001
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Ingår i: Heart. - : BMJ Group. - 1355-6037 .- 1468-201X. ; 86:4, s. 391-396
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE—To describe the mortality during the subsequent 10 years for subsets of patients hospitalised for suspected acute coronary syndrome. PATIENTS AND METHODS—All patients who were admitted to the emergency department in one hospital during 21 months for chest pain or other symptoms raising suspicion of an acute coronary syndrome were registered. From this baseline population three subgroups were defined among those being hospitalised: patients who developed a Q wave acute myocardial infarction (AMI) (n = 306); patients who developed a non-Q wave AMI (n = 527); and patients who developed confirmed or possible myocardial ischaemia (unstable angina pectoris) (n = 1274). These three groups were compared in terms of 10 year mortality. RESULTS—Patients who developed a non-Q wave AMI had the highest 10 year mortality (70.3%), significantly higher than those who developed a Q wave AMI (60.1%; p = 0.004) and those who had confirmed or possible myocardial ischaemia (50.1%; p < 0.0001). There was no difference between patients with confirmed and those with possible myocardial ischaemia (50.0% and 50.1%, respectively). After correction for dissimilarities in age, sex, and history the adjusted risk ratio for death in patients with a non-Q wave AMI compared with Q wave AMI was 1.01 (95% confidence interval (CI) 0.82 to 1.25). The corresponding risk ratio for death in patients with a non-Q wave AMI compared with confirmed or possible myocardial ischaemia was 1.91 (95% CI 1.64 to 2.23). There was also an imbalance in drug regimens among groups. CONCLUSION—This study shows that in a non-selected population of patients hospitalised with a suspected acute coronary syndrome, the highest risk of death is found in those with a non-Q wave AMI and the lowest in those with confirmed or possible myocardial ischaemia. Thus, patients with a Q wave AMI have a long term mortality risk intermediate between the two fractions defined as having unstable coronary artery disease. However, adjusting these results for age and history of cardiovascular disease eliminated the observed difference in mortality between non-Q wave and Q wave AMI. Furthermore, an imbalance in drug regimens might have affected the outcome.
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| 7. |
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| 8. |
- Huang, Hui, et al.
(författare)
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Comparison between AFM-based methods for assesing local surface mechanical properties of PDMS-silica composite layers
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Local surface mechanical properties of polymeric nanocomposites play a significant role in theirperformance. Atomic Force Microscopy (AFM) can be used to perform measurements of suchproperties with high lateral resolution. The interphase between filler and matrix, and how it can becontrolled by means of surface chemistry is of particular interest. In this work we compare threeoperating modes of AFM: Tapping mode, PeakForce QNM (Quantitative Nanomechanical Mapping)and Intermodulation AFM (ImAFM), for their ability to capture the tip-surface force and to extractlocal mechanical properties by applying different contact mechanics models. Layers ofpoly(dimethylsiloxane) (PDMS) with and without 20 wt.% of hydrophobic silica nanoparticles werestudied employing these AFM modes. We show that tapping mode AFM can provide qualitativeinformation, but it is insufficient to accurately and quantitatively discriminate surface propertiessince this mode does not allow extraction of the tip-surface force. Quantitative mapping ofmechanical properties is possible with both PeakForce QNM and ImAFM. However, it remained achallenge to evaluate the data for soft PDMS layers with PeakForce QNM. Local surface mechanicalproperties could be more reproducibly assessed via ImAFM. We show that the Tapping modeimages for pure PDMS report a relatively homogeneous surface, but as we utilize PeakForce QNMand ImAFM more details appear and the inhomogeneous nature of the surface layer becomesapparent. Incorporation of silica particles in the PDMS layer results in a significant increase in theapparent stiffness of the matrix. All imaging modes allow visualization of the hard particles in thesoft matrix. However, we were most successful with imaging the interphase using ImAFM.
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| 9. |
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| 10. |
- Jakobsson, Stefan
(författare)
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Weighted Bergman kernels and biharmonic Green functions
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main theme of this thesis is the connection between weighted biharmonic Green functions and weighted Bergman kernels. In the first paper, which is a joint work with H. Hedenmalm and S. Shimorin, we prove that weighted biharmonic Green functions are positive for weights which satisfy a mean-value condition and whose logarithms are subharmonic. To achieve this, we use a variational formula due to J. Hadamard, weighted Hele-Shaw flow, as well as a new structural formula for the analytic Bergman kernel. The result has applications to the factorization theory in weighted Bergman spaces. In the subsequent papers, we continue to investigate Bergman kernels and Green functions. In the second paper, we analyze the singularity of the weighted analytic and harmonic Bergman kernels for a general smooth weight in a domain with smooth boundary. In the third paper, we apply the theory of semigroups to one of the arguments in the first paper. It turns out that if the harmonic Bergman kernel for a starshaped domain satisfies a certain inequality, then the biharmonic Green function for the domain is positive. In the fourth paper, we show how the Friedrichs operator can be used to expand the harmonic Bergman kernel in terms of the analytic counterpart for a simply connected domain. Under certain conditions on the conformal map from the unit disk to the domain, we obtain a pointwise estimate of the harmonic Bergman kernel.
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