| 1. |
- Abel, I, et al.
(author)
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Overview of the JET results with the ITER-like wall
- 2013
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In: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Journal article (peer-reviewed)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 2. |
- Romanelli, F, et al.
(author)
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Overview of the JET results
- 2011
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In: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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Journal article (peer-reviewed)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
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| 3. |
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| 4. |
- Dunlop, Malcolm G, et al.
(author)
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Cumulative impact of 10 common genetic variants on colorectal cancer risk in 42,333 individuals from eight populations
- 2012
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In: Gut. - Stockholm : Karolinska Institutet, Dept of Molecular Medicine and Surgery. - 1468-3288 .- 0017-5749.
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Colorectal cancer (CRC) has a substantial heritable component. Common genetic variation has been shown to contribute to CRC risk. A study was conducted in a large multi-population study to assess the feasibility of CRC risk prediction using common genetic variant data combined with other risk factors. A risk prediction model was built and applied to the Scottish population using available data. DESIGN: Nine populations of European descent were studied to develop and validate CRC risk prediction models. Binary logistic regression was used to assess the combined effect of age, gender, family history (FH) and genotypes at 10 susceptibility loci that individually only modestly influence CRC risk. Risk models were generated from case-control data incorporating genotypes alone (n=39 266) and in combination with gender, age and FH (n=11 324). Model discriminatory performance was assessed using 10-fold internal cross-validation and externally using 4187 independent samples. The 10-year absolute risk was estimated by modelling genotype and FH with age- and gender-specific population risks. RESULTS: The median number of risk alleles was greater in cases than controls (10 vs 9, p<2.2×10(-16)), confirmed in external validation sets (Sweden p=1.2×10(-6), Finland p=2×10(-5)). The mean per-allele increase in risk was 9% (OR 1.09; 95% CI 1.05 to 1.13). Discriminative performance was poor across the risk spectrum (area under curve for genotypes alone 0.57; area under curve for genotype/age/gender/FH 0.59). However, modelling genotype data, FH, age and gender with Scottish population data shows the practicalities of identifying a subgroup with >5% predicted 10-year absolute risk. CONCLUSION: Genotype data provide additional information that complements age, gender and FH as risk factors, but individualised genetic risk prediction is not currently feasible. Nonetheless, the modelling exercise suggests public health potential since it is possible to stratify the population into CRC risk categories, thereby informing targeted prevention and surveillance.
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| 5. |
- Hoare, M. G., et al.
(author)
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The cradle of life and the SKA
- 2014
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In: Proceedings of Science. - 1824-8039. ; 9-13-June-2014
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Conference paper (peer-reviewed)abstract
- We provide an overview of the exciting capabilities of the SKA in the Cradle of Life theme. With the deployment of the high frequency band 5 receivers, the phase 1 of the SKA can conduct headline science in the study of the earliest stages of grain growth in proto-planetary disks. SKA1-MID can map the 2 cm continuum emission at a resolution of 4 au in the nearest systems and therefore begin to probe the distribuion of cm-sized particles across the snow line. This frequency range will also enable deep searches for pre-biotic molecules such as amino acids from pre-stellar cores to the cold, outer regions of proto-planetary disks where cometary material forms. The lowest frequency capabilities of SKA1 can be used to examine the magnetic fields of exo-planets via their auroral radio emission. This gives unique insight into their interiors and could potentially detect exo-moons. Across the full frequency range, the SKA1 will also carry out systematic, volume-limited searches of exo-planet systems for signals from technologically advanced civilizations. The sensitivity of SKA1 means that these only need to be at the level of typical airport radar signals in the nearest systems. Hence, the SKA1 can conduct high impact science from the first steps on the road to planets and life, through areas affecting the habitability of planets, and ultimately, to whether we are alone in the Galaxy. These inspirational themes will greatly help in the effort to bring SKA1 science to a wide audience and to ensure the progression to the full SKA.
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| 6. |
- Becker, Chandler A., et al.
(author)
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Thermodynamic modelling of liquids : CALPHAD approaches and contributions from statistical physics
- 2014
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In: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 251:1, s. 33-52
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Journal article (peer-reviewed)abstract
- We describe current approaches to thermodynamic modelling of liquids for the CALPHAD method, the use of available experimental methods and results in this type of modelling, and considerations in the use of atomic-scale simulation methods to inform a CALPHAD approach. We begin with an overview of the formalism currently used in CALPHAD to describe the temperature dependence of the liquid Gibbs free energy and outline opportunities for improvement by reviewing the current physical understanding of the liquid. Brief descriptions of experimental methods for extracting high-temperature data on liquids and the preparation of undercooled liquid samples are presented. Properties of a well-determined substance, B-2 O-3, including the glass transition, are then discussed in detail to emphasize specific modelling requirements for the liquid. We then examine the two-state model proposed for CALPHAD in detail and compare results with experiment and theory, where available. We further examine the contributions of atomic-scale methods to the understanding of liquids and their potential for supplementing available data. We discuss molecular dynamics (MD) and Monte Carlo methods that employ atomic interactions from classical interatomic potentials, as well as contributions from ab initio MD. We conclude with a summary of our findings.
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| 7. |
- Fielding, Roger A., et al.
(author)
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Sarcopenia : An Undiagnosed Condition in Older Adults. Current Consensus Definition: Prevalence, Etiology, and Consequences. International Working Group on Sarcopenia
- 2011
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In: Journal of the American Medical Directors Association. - : Elsevier BV. - 1525-8610 .- 1538-9375. ; 12:4, s. 249-256
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Journal article (peer-reviewed)abstract
- Sarcopenia, the age-associated loss of skeletal muscle mass and function, has considerable societal consequences for the development of frailty, disability, and health care planning. A group of geriatricians and scientists from academia and industry met in Rome, Italy, on November 18, 2009, to arrive at a consensus definition of sarcopenia. The current consensus definition was approved unanimously by the meeting participants and is as follows: Sarcopenia is defined as the age-associated loss of skeletal muscle mass and function. The causes of sarcopenia are multifactorial and can include disuse, altered endocrine function, chronic diseases, inflammation, insulin resistance, and nutritional deficiencies. Although cachexia may be a component of sarcopenia, the 2 conditions are not the same. The diagnosis of sarcopenia should be considered in all older patients who present with observed declines in physical function, strength, or overall health. Sarcopenia should specifically be considered in patients who are bedridden, cannot independently rise from a chair, or who have a measured gait speed less that 1 m/s(-1). Patients who meet these criteria should further undergo body composition assessment using dual energy x-ray absorptiometry with sarcopenia being defined using currently validated definitions. A diagnosis of sarcopenia is consistent with a gait speed of less than 1 m.s(-1) and an objectively measured low muscle mass (eg, appendicular mass relative to ht(2) that is <= 7.23 kg/m(2) in men and <= 5.67 kg/m(2) in women). Sarcopenia is a highly prevalent condition in older persons that leads to disability, hospitalization, and death.
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