| 1. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 2. |
- Westerhof, E., et al.
(författare)
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Control of sawteeth and triggering of NTMs with ion cyclotron resonance frequency waves in JET
- 2002
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 42:11, s. 1324-1334
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Tidskriftsartikel (refereegranskat)abstract
- A new scenario to delay or prevent neoclassical tearing mode (NTM) onset is presented. By active sawtooth destabilization, short period and low amplitude sawteeth are generated, such that the sawtooth produced NTM seed island is reduced and the threshold normalized plasma pressure for triggering of NTMs, beta(Nonset), is increased. The scenario has been explored experimentally in the Joint European Torus (JET). Ion cyclotron resonance frequency (ICRF) waves tuned to the 2nd harmonic H-minority resonance have been used for sawtooth control. Whereas ICRF waves generally induce sawtooth stabilization, favouring the triggering of NTMs and reducing beta(Nonset), the present experiments show that by toroidally directed waves, ion cyclotron current drive is produced, and that sawteeth can be destabilized by careful positioning of the 2nd harmonic H resonance layer with respect to the sawtooth inversion radius. As a result, NTM onset is delayed and beta(Nonset) is increased above its value obtained in discharges with additional heating from neutral beam injection alone.
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| 3. |
- Sauter, O., et al.
(författare)
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Control of neoclassical tearing modes by sawtooth control
- 2002
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 88:10
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Tidskriftsartikel (refereegranskat)abstract
- The onset of a neoclassical tearing mode (NTM) depends on the existence of a large enough seed island. It is shown in the Joint European Torus that NTMs can be readily destabilized by long-period sawteeth, such as obtained by sawtooth stabilization from ion-cyclotron heating or current drive. This has important implications for burning plasma scenarios, as alpha particles strongly stabilize the sawteeth. It is also shown that, by adding heating and current drive just outside the inversion radius, sawteeth are destabilized, resulting in shorter sawtooth periods and larger beta values being obtained without NTMs.
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| 4. |
- Liu, Yueqiang, 1971, et al.
(författare)
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Feedback and rotational stabilization of resistive wall modes in ITER
- 2004
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Ingår i: 20th IAEA Fusion Energy Conference,Vilamoura, Portugal, 1-6 November 2004. ; TH, s. 2-1
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Different models have been introduced in the stability code MARS-F in order tostudy the damping effect of resistive wall modes (RWM) in rotating plasmas. Benchmarkof MARS-F calculations with RWM experiments on JET and D3D indicates thatthe semi-kinetic damping model is a good candidate for explaining the dampingmechanisms. Based on these results, the critical rotation speeds required forRWM stabilization in an advanced ITER scenario are predicted. Active feedbackcontrol of the $n=1$ RWM in ITER is also studied using the MARS-F code.
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| 5. |
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| 6. |
- Hender, T. C., et al.
(författare)
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MHD stability with strongly reversed magnetic shear in JET
- 2002
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 44:7, s. 1143-1154
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Tidskriftsartikel (refereegranskat)abstract
- Recent operation of JET with centrally strongly reversed magnetic shear, produced with the help of lower hybrid current drive, has extended the domain in which internal transport barriers (ITBs) can be formed in JET. Performance is frequently limited by magnetohydrodynamic (MHD) instabilities in these reversed shear regimes. The most severe limit is a pressure driven kink mode which leads to a disruption. This disruptive limit is essentially the same in ITB plasmas with low or strongly reversed shear. Unique to the reversed shear regime is a dominantly n = 1 mode, which has multiple harmonics. This mode is a seemingly common limit to performance, in the highest performance plasmas. Also unique to the reversed shear regime are q > 1 sawteeth events, which can in turn trigger n = 1 post-cursor oscillations. In general, these post-cursor oscillations are benign but do provide valuable information on the q-profile. Other instabilities, including 'snakes' at the outer q = 3 surface, are also observed to limit the performance of reversed magnetic shear ITB regimes.
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| 7. |
- Jobs, M, et al.
(författare)
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Creating arrays by centrifugation
- 2002
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Ingår i: BioTechniques. - : Future Science Ltd. - 0736-6205 .- 1940-9818. ; 32:6, s. 1322-
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Tidskriftsartikel (refereegranskat)abstract
- We describe a fast, low-cost, and reliable way of creating arrays from sample molecules of interest present within microformatted sample vessels (such as 1536-well microplates). The principle involves simple centrifugal transfer of molecules of interest onto a solid planar or membrane surfaces placed over the initial sample vessel. Tools and procedures are presented that validate the robustness and precision of this facile solution to an otherwise difficult problem in modern molecular genetics. The availability of transferred DNA molecules for hybridization is also demonstrated. In conclusion, this “centrifugal-array” concept should help research studies to be applied on ever-greater scales with very simple machinery.
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| 8. |
- Jobs, M, et al.
(författare)
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DASH-2: flexible, low-cost, and high-throughput SNP genotyping by dynamic allele-specific hybridization on membrane arrays
- 2003
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Ingår i: Genome research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 13:5, s. 916-924
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Tidskriftsartikel (refereegranskat)abstract
- Genotyping technologies need to be continually improved in terms of their flexibility, cost-efficiency, and throughput, to push forward genome variation analysis. To this end, we have leveraged the inherent simplicity of dynamic allele-specific hybridization (DASH) and coupled it to recent innovations of centrifugal arrays and iFRET. We have thereby created a new genotyping platform we term DASH-2, which we demonstrate and evaluate in this report. The system is highly flexible in many ways (any plate format, PCR multiplexing, serial and parallel array processing, spectral-multiplexing of hybridization probes), thus supporting a wide range of application scales and objectives. Precision is demonstrated to be in the range 99.8–100%, and assay costs are 0.05 USD or less per genotype assignment. DASH-2 thus provides a powerful new alternative for genotyping practice, which can be used without the need for expensive robotics support.
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| 9. |
- Liu, Yueqiang, 1971, et al.
(författare)
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Modeling of Resistive Wall Mode Experiments in JET
- 2004
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Ingår i: 30th EPS Conference on Plasma Physics and Controlled Fusion, June 28 - July 2, 2004, Imperial College, London, UK.. ; P1, s. 166-
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Konferensbidrag (refereegranskat)
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| 10. |
- Moller, P, et al.
(författare)
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Survival in prospectively ascertained familial breast cancer: Analysis of a series stratified by tumour characteristics, BRCA mutations and oophorectomy
- 2002
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 101:6, s. 555-559
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Tidskriftsartikel (refereegranskat)abstract
- Dedicated clinics have been established for the early diagnosis and treatment of women at risk for inherited breast cancer, but the effects of such interventions are currently unproven. This second report on prospectively diagnosed inherited breast cancer from the European collaborating centres supports the previous conclusions and adds information on genetic heterogeneity and the effect of oophorectomy. Of 249 patients, 20% had carcinoma in situ (CIS), 54% had infiltrating cancer without spread (CaNO) and 26% had cancer with spread (CaN+). Five-year survival was 100% for CIS, 94% for CaNO and 72% for CaN+ (p = 0.007). Thirty-six patients had BRCA1 mutations, and 8 had BRCA2 mutations. Presence of BRCA1 mutation was associated with infiltrating cancer, high grade and lack of oestrogen receptor (p < 0.05 for all 3 characteristics). For BRCA1 mutation carriers, 5-year survival was 63% vs. 91% for noncarriers (p = 0.04). For CaNO patients, mutation carriers had 75% S-year disease-free survival vs. 96% for noncarriers (p = 0.01). Twenty-one of the mutation carriers had undergone prophylactic oophorectomy, prior to or within 6 months of diagnosis in 13 cases. All but I relapse occurred in the I S who had kept their ovaries, (p < 0.01); no relapse occurred in those who had removed the ovaries within 6 months (p = 0.04) Contralateral cancer was more frequently observed in mutation noncarriers, but this finding did not reach statistical significance. Our findings support the concept that BRCA1 cancer is biologically different from other inherited breast cancers. While current screening protocols appear satisfactory for the majority of women at risk of familial breast cancer, this may not be the case for BRCA1 mutation carriers. The observed effect of oophorectomy was striking.
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