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| 55. |
- Arnichand, H., et al.
(författare)
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Discriminating the trapped electron modes contribution in density fluctuation spectra
- 2015
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Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 55:9
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Tidskriftsartikel (refereegranskat)abstract
- Quasi-coherent (QC) modes have been reported for more than 10 years in reflectometry fluctuations spectra in the core region of fusion plasmas. They have characteristics in-between coherent and broadband fluctuations as they oscillate at a marked frequency but have a wide spectrum. This work presents further evidences of the link recently established between QC modes and the trapped electron modes (TEM) instabilities (Arnichand et al 2014 Nucl. Fusion 54 123017). In electron cyclotron resonance heated discharges of Tore Supra, an enhancement of QC modes amplitude is observed in a region where TEM cause impurity transport and turbulence. In JET Ohmic plasmas, QC modes disappear during density ramp-up and current ramp-down. This is reminiscent of Tore Supra and TEXTOR observations during transitions from the linear Ohmic confinement (LOC) to the saturated Ohmic confinement (SOC) regimes. Evidencing TEM activity then becomes experimentally possible via analysis of fluctuation spectra.
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| 56. |
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| 57. |
- Bowman, C., et al.
(författare)
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Pedestal evolution physics in low triangularity JET tokamak discharges with ITER-like wall
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 58:1
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Tidskriftsartikel (refereegranskat)abstract
- The pressure gradient of the high confinement pedestal region at the edge of tokamak plasmas rapidly collapses during plasma eruptions called edge localised modes (ELMs), and then re-builds over a longer time scale before the next ELM. The physics that controls the evolution of the JET pedestal between ELMs is analysed for 1.4 MA, 1.7 T, low triangularity, delta = 0.2, discharges with the ITER-like wall, finding that the pressure gradient typically tracks the ideal magneto-hydrodynamic ballooning limit, consistent with a role for the kinetic ballooning mode. Furthermore, the pedestal width is often influenced by the region of plasma that has second stability access to the ballooning mode, which can explain its sometimes complex evolution between ELMs. A local gyrokinetic analysis of a second stable flux surface reveals stability to kinetic ballooning modes; global effects are expected to provide a destabilising mechanism and need to be retained in such second stable situations. As well as an electronscale electron temperature gradient mode, ion scale instabilities associated with this flux surface include an electro-magnetic trapped electron branch and two electrostatic branches propagating in the ion direction, one with high radial wavenumber. In these second stability situations, the ELM is triggered by a peeling-ballooning mode; otherwise the pedestal is somewhat below the peeling-ballooning mode marginal stability boundary at ELM onset. In this latter situation, there is evidence that higher frequency ELMs are paced by an oscillation in the plasma, causing a crash in the pedestal before the peeling-ballooning boundary is reached. A model is proposed in which the oscillation is associated with hot plasma filaments that are pushed out towards the plasma edge by a ballooning mode, draining their free energy into the cooler plasma there, and then relaxing back to repeat the process. The results suggest that avoiding the oscillation and maximising the region of plasma that has second stability access will lead to the highest pedestal heights and, therefore, best confinement-a key result for optimising the fusion performance of JET and future tokamaks, such as ITER.
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| 58. |
- Breton, Gwenna, et al.
(författare)
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Deciphering early human history using Approximate Bayesian Computation and 74 whole genomes from Central and Southern Africa
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Human evolutionary history in Africa before and after the out-of-Africa event remains largely unexplored, due to lack of genome sequence data, limited representation of populations and limitations of presently available inference methods. We generated high-coverage genomes from 49 Central African individuals, from five rainforest hunter-gatherer populations and four neighboring populations, and from 25 Khoe-San individuals, from five populations. We analyzed these genomes jointly with 104 comparative genomes from worldwide populations. We showed that rainforest hunter-gatherers and Khoe-San populations define two distinct major axes of genetic variation both at the worldwide and Sub-Saharan scales. This new data provides unprecedented resolution to unravel complex genetic differentiation among rainforest hunter-gatherer populations in particular. Using both deterministic and Approximate Bayesian Computation inferences, we found strong support for gene flow throughout the entire history of Central and Southern Africa, and an early divergence, some 250-370 kya ago, of Khoe-San ancestors from the lineage ancestral to all Central African populations. This event was followed, still in the presence of gene-flow, some 80-240 kya, by the divergence of lineages ancestral to rainforest hunter-gatherers and their neighbors. Finally, divergence between the different Khoe-San populations likely predated that of eastern and western rainforest hunter-gatherers which occurred 16-44 kya. Altogether, our results indicate that a tree-like history of Central Africa incorporating gene-flow among ancient lineages as well as among recent lineages can explain genomic variation observed among populations today.
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| 59. |
- Buckley, Andy, et al.
(författare)
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General-purpose event generators for LHC physics
- 2011
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573. ; 504:5, s. 145-233
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Forskningsöversikt (refereegranskat)abstract
- We review the physics basis, main features and use of general-purpose Monte Carlo event generators for the simulation of proton-proton collisions at the Large Hadron Collider. Topics included are: the generation of hard scattering matrix elements for processes of interest, at both leading and next-to-leading QCD perturbative order; their matching to approximate treatments of higher orders based on the showering approximation; the parton and dipole shower formulations; parton distribution functions for event generators; non-perturbative aspects such as soft QCD collisions, the underlying event and diffractive processes; the string and cluster models for hadron formation; the treatment of hadron and tau decays; the inclusion of QED radiation and beyond Standard Model processes. We describe the principal features of the ARIADNE, Herwig++, PYTHIA 8 and SHERPA generators, together with the Rivet and Professor validation and tuning tools, and discuss the physics philosophy behind the proper use of these generators and tools. This review is aimed at phenomenologists wishing to understand better how parton-level predictions are translated into hadron-level events as well as experimentalists seeking a deeper insight into the tools available for signal and background simulation at the LHC. (C) 2011 Elsevier B.V. All rights reserved.
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| 60. |
- Butt, Jawad H., et al.
(författare)
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Efficacy and Safety of Dapagliflozin in Men and Women With Heart Failure With Reduced Ejection Fraction : A Prespecified Analysis of the Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure Trial.
- 2021
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Ingår i: JAMA cardiology. - : American Medical Association (AMA). - 2380-6583 .- 2380-6591. ; 6:6, s. 678-689
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Women may respond differently to certain treatments for heart failure (HF) with reduced ejection fraction (HFrEF) than men. Objective: To investigate the efficacy and safety of dapagliflozin compared with placebo in men and women with HFrEF enrolled in the Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure trial (DAPA-HF). Design, Setting, and Participants: Prespecified subgroup analysis of a phase 3 randomized clinical trial conducted at 410 sites in 20 countries. Patients with New York Heart Association functional class II through IV with an ejection fraction of 40% or less and elevated N-terminal pro-B- type natriuretic peptide were eligible. Data were analyzed between June 2020 and January 2021. Interventions: Addition of once-daily 10 mg of dapagliflozin or placebo to guideline-recommended therapy. Main Outcomes and Measures: The primary outcome was the composite of an episode of worsening HF (HF hospitalization or urgent HF visit requiring intravenous therapy) or cardiovascular death. Results: A total of 4744 patients were randomized in DAPA-HF, of whom 1109 were women (23.4%). Compared with placebo, dapagliflozin reduced the risk of worsening HF events or cardiovascular death to a similar extent in both men and women (hazard ratios, 0.73 [95% CI, 0.63-0.85] and 0.79 [95% CI, 0.59-1.06], respectively; P for interaction = .67). Consistent benefits were observed for the components of the primary outcome and all-cause mortality. Compared with placebo, dapagliflozin increased the proportion of patients with a meaningful improvement in symptoms (Kansas City Cardiomyopathy Questionnaire total symptom score of $>$/=5 points; men, 59% vs 50%; women, 57% vs 54%; P for interaction = .14) and decreased the proportion with worsening symptoms (Kansas City Cardiomyopathy Questionnaire total symptom score decrease of $>$/=5 points; men, 25% vs 34%; women, 27% vs 31%; P for interaction = .15), irrespective of sex. Results were consistent for the Kansas City Cardiomyopathy Questionnaire clinical summary score and overall summary score. Study drug discontinuation and serious adverse events were not more frequent in the dapagliflozin group than in the placebo group in either men or women. Conclusions and Relevance: Dapagliflozin reduced the risk of worsening HF, cardiovascular death, and all-cause death and improved symptoms, physical function, and health-related quality of life similarly in men and women with heart failure and reduced ejection fraction. In addition, dapagliflozin was safe and well-tolerated irrespective of sex. Trial Registration: ClinicalTrials.gov Identifier: NCT03036124.
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