| 1. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 2. |
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| 3. |
- Wang, HD, et al.
(författare)
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Global, regional, national, and selected subnational levels of stillbirths, neonatal, infant, and under-5 mortality, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015
- 2016
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Ingår i: Lancet (London, England). - : Elsevier. - 1474-547X .- 0140-6736. ; 388:10053, s. 1725-1774
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Tidskriftsartikel (refereegranskat)
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| 4. |
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| 5. |
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| 6. |
- Chapman, I. T., et al.
(författare)
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Overview of MAST results
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10
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Tidskriftsartikel (refereegranskat)abstract
- The Mega Ampere Spherical Tokamak (MAST) programme is strongly focused on addressing key physics issues in preparation for operation of ITER as well as providing solutions for DEMO design choices. In this regard, MAST has provided key results in understanding and optimizing H-mode confinement, operating with smaller edge localized modes (ELMs), predicting and handling plasma exhaust and tailoring auxiliary current drive. In all cases, the high-resolution diagnostic capability on MAST is complemented by sophisticated numerical modelling to facilitate a deeper understanding. Mitigation of ELMs with resonant magnetic perturbations (RMPs) with toroidal mode number n(RMP) = 2, 3, 4, 6 has been demonstrated: at high and low collisionality; for the first ELM following the transition to high confinement operation; during the current ramp-up; and with rotating n(RMP) = 3 RMPs. n(RMP) = 4, 6 fields cause less rotation braking whilst the power to access H-mode is less with n(RMP) = 4 than n(RMP) = 3, 6. Refuelling with gas or pellets gives plasmas with mitigated ELMs and reduced peak heat flux at the same time as achieving good confinement. A synergy exists between pellet fuelling and RMPs, since mitigated ELMs remove fewer particles. Inter-ELM instabilities observed with Doppler backscattering are consistent with gyrokinetic simulations of micro-tearing modes in the pedestal. Meanwhile, ELM precursors have been strikingly observed with beam emission spectroscopy (BES) measurements. A scan in beta at the L-H transition shows that pedestal height scales strongly with core pressure. Gyro-Bohm normalized turbulent ion heat flux (as estimated from the BES data) is observed to decrease with increasing tilt of the turbulent eddies. Fast ion redistribution by energetic particle modes depends on density, and access to a quiescent domain with 'classical' fast ion transport is found above a critical density. Highly efficient electron Bernstein wave current drive (1 A W-1) has been achieved in solenoid-free start-up. A new proton detector has characterized escaping fusion products. Langmuir probes and a high-speed camera suggest filaments play a role in particle transport in the private flux region whilst coherence imaging has measured scrape-off layer (SOL) flows. BOUT++ simulations show that fluxes due to filaments are strongly dependent on resistivity and magnetic geometry of the SOL, with higher radial fluxes at higher resistivity. Finally, MAST Upgrade is due to begin operation in 2016 to support ITER preparation and importantly to operate with a Super-X divertor to test extended leg concepts for particle and power exhaust.
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| 7. |
- Prigge, R., et al.
(författare)
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International comparison of glycaemic control in people with type 1 diabetes: an update and extension
- 2022
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Ingår i: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 39:5
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To update and extend a previous cross-sectional international comparison of glycaemic control in people with type 1 diabetes. Methods: Data were obtained for 520,392 children and adults with type 1 diabetes from 17 population and five clinic-based data sources in countries or regions between 2016 and 2020. Median HbA1c(IQR) and proportions of individuals with HbA1c < 58mmol/mol (<7.5%), 58–74mmol/mol (7.5–8.9%) and ≥75mmol/mol (≥9.0%) were compared between populations for individuals aged <15, 15–24 and ≥25 years. Logistic regression was used to estimate the odds ratio (OR) of HbA1c < 58mmol/mol (<7.5%) relative to ≥58mmol/mol (≥7.5%), stratified and adjusted for sex, age and data source. Where possible, changes in the proportion of individuals in each HbA1c category compared to previous estimates were calculated. Results: Median HbA1c varied from 55 to 79mmol/mol (7.2 to 9.4%) across data sources and age groups so a pooled estimate was deemed inappropriate. OR (95% CI) for HbA1c< 58mmol/mol (<7.5%) were 0.91 (0.90–0.92) for women compared to men, 1.68 (1.65–1.71) for people aged <15years and 0.81 (0.79–0.82) aged15–24years compared to those aged ≥25years. Differences between populations persisted after adjusting for sex, age and data source. In general, compared to our previous analysis, the proportion of people with an HbA1c<58mmol/l (<7.5%) increased and proportions of people with HbA1c≥ 75mmol/mol (≥9.0%) decreased. Conclusions: Glycaemic control of type 1 diabetes continues to vary substantially between age groups and data sources. While some improvement over time has been observed, glycaemic control remains sub-optimal for most people with Type 1 diabetes.
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| 9. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 10. |
- Diallo, P. I., et al.
(författare)
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A formal, model-driven design flow for system simulation and multi-core implementation
- 2015
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Ingår i: 2015 10th IEEE International Symposium on Industrial Embedded Systems. - : IEEE. - 9781467377119 ; , s. 254-263
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Konferensbidrag (refereegranskat)abstract
- With the growing complexity of Real-Time Embedded Systems (RTES), there is a huge interest in using modeling languages such as the Unified Modeling Language (UML), and other Model-Driven Engineering (MDE) techniques targeting RTES system design. These approaches provide language abstractions for system design, allowing to focus on their relevant properties. Unfortunately, such approaches still suffer from several shortcomings including the lack of well-defined semantics. Therefore, it remains difficult to connect the MDE specification tools and the design tools that are based on formal grounds and well-defined semantics to perform analysis, validation or system synthesis for RTES. This paper presents a top-down RTES design flow aiming to reduce the gap between MDE and formal design approaches. We present the connection between a framework dedicated to the enrichment of modeling languages such as UML with formal semantics, a framework based on formal models of computation supporting validation by simulation, and a system synthesis tool targeting a flexible platform with well-defined execution services. Our purpose is to cover several system design phases from specification, simulation down to implementation on a platform. As a case study, a JPEG Encoder application was realized following the different design steps of the tool-chain.
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