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Your search keyword '"Holmström, K."' showing total 6 results
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6 results on '"Holmström, K."'

1. Overview of recent results on Heating and Current Drive in JET.

Author

Ongena, J., Baranov, Yu., Bobkov, V., Challis, C. D., Colas, L., Durodié, F., Ekedahl, A., Eriksson, L.-G., Jacquet, Ph., Jenkins, I., Johnson, T., Goniche, M., Granucci, G., Hellsten, T., Holmström, K., Kiptily, V., Kirov, K., Krasilnikov, A., Laxåback, M., and Lerche, E.

Subjects
ELECTRIC currents, ELECTRIC power, ANTENNAS (Electronics), IONS, CYCLOTRONS
Abstract

Recent progress on heating and current drive on JET is reported. Topics discussed are: high power coupling of ICRF/LH at ITER relevant antenna/launcher-separatrix distances, succesfull demonstration of 3 dB couplers for ELM tolerance of the ICRF system, influence of ICRF on LH operation, rotation studies in plasma without external momentum with standard and enhanced JET toriodal field ripple, studies of different ICRF heating schemes and of NTM avoidance schemes using Ion Cyclotron Current Drive. A brief outlook on future plans for experiments at JET is given. [ABSTRACT FROM AUTHOR]

Published
2007
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2. Effects of ICRH on the Dynamics of Fast Particle Excited Alfvén Eigenmodes.

Author

Bergkvist, T., Hellsten, T., and Holmström, K.

Subjects
PARTICLES, DISTRIBUTION (Probability theory), PROPERTIES of matter, COMPUTER simulation, ANISOTROPY
Abstract

ICRH is often used in experiments to simulate destabilization of Alfvén eigenmodes by thermonuclear α-particles. Whereas the slowing down distribution of α-particles is nearly isotropic, the ICRH creates an anisotropic distribution function with non-standard orbits. The ICRH does not only build up gradients in phase space, which destabilizes the AEs, but it also provides a strong phase decorrelation mechanism between ions and AEs. Renewal of the distribution function by thermonuclear reactions and losses of α-particles to the wall lead to a continuous drive of the AEs. Simulations of the non-linear dynamics of AEs and the impact they have on the heating profile due to particle redistribution are presented. [ABSTRACT FROM AUTHOR]

Published
2007
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3. Toroidal Rotation in RF Heated JET Plasmas.

Author

Eriksson, L.-G., Hellsten, T., Nave, F., Brzozowski, J., Holmström, K., Johnson, T., Ongena, J., and Zastrow, K.-D.

Subjects
CYCLOTRON resonance, ELECTRIC currents, SPECTRUM analysis, QUANTUM electrodynamics, RESONANCE
Abstract

Experiments have been carried out on JET aimed at studying rotation in RF heated plasmas with low external momentum input. Both plasmas with Ion Cyclotron Resonance Frequency (ICRF) heating and Lower Hybrid Current Drive (LHCD) have been investigated. The rotation profiles are measured by Charge Exchange recombination spectroscopy, using short diagnostic Neutral Beam Injection (NBI) pulses. Moreover, the temporal evolution of the central rotation could in some cases be deduced from MHD activity. While most of the measurements were focussed on ICRF heating, the profiles measured in plasmas with LHCD are interesting since they are the first reported from JET in such plasmas. In particular, they allowed for studies of rotation in RF heated plasmas with q>1. The experimental results are presented together with an analysis of the torque from ICRF heated fast ions. [ABSTRACT FROM AUTHOR]

Published
2007
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4. Rapid identification of pathogenic yeast isolates by real-time PCR and two-dimensional melting-point analysis.

Author

Bergman, A., Fernandez, V., Holmström, K. O., Claesson, B. E. B., and Enroth, H.

Subjects
GENES, HEREDITY, LEAVENING agents, BIOLOGICAL laboratories, LABORATORIES, RESEARCH, PATHOGENIC microorganisms, CANDIDA, CANDIDIASIS
Abstract

There is a need in the clinical microbiological laboratory for rapid and reliable methods for the universal identification of fungal pathogens. Two different regions of the rDNA gene complex, the highly polymorphic ITS1 and ITS2, were amplified using primers targeting conserved regions of the 18S, 5.8S and 28S genes. After melting-point analysis of the amplified products, the Tm of the two PCR-products were plotted into a spot diagram where all the 14 tested, clinically relevant yeasts separated with good resolution. Real-time amplification of two separate genes, melting-point analysis and two-dimensional plotting of Tm data can be used as a broad-range method for the identification of clinical isolates of pathogenic yeast such as Candida and Cryptococcus spp. [ABSTRACT FROM AUTHOR]

Published
2007
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5. Cardiac rhythm in patients with sleep-disordered breathing and coronary artery disease.

Author

Mooe, Thomas, Franklin, Karl A., Wiklund, Urban, Rabben, Terje, Holmström, Karin, Mooe, T, Franklin, K A, Wiklund, U, Rabben, T, and Holmström, K

Subjects
SLEEP apnea syndromes, ARRHYTHMIA
Abstract

We examined the effect of sleep-disordered breathing on heart rates and arrhythmias in men and women with disabling angina pectoris and verified coronary artery disease by an overnight sleep study and Holter recording. The number of oxyhaemoglobin desaturations > or =4% (ODI) and number of apnoea-hypopnoeas per hour of sleep (AHI) were recorded. ODI > or =5 and AHI > or =10 were used as measures of disordered breathing and patients below these limits formed the control groups. One-hundred and forty-one men and 98 women < or =70 years of age were randomly included. Thirty-eight percent of the men and 36% of the women had an ODI > or =5. No serious ventricular arrhythmias occurred. Women with disordered breathing (ODI > or =5) had higher heart rates (mean 63.3 vs 59.1, p < 0.05) and a higher occurrence of ventricular premature contractions (VPCs) during sleep (75th percentiles 2.5 vs 0.5 per hour, p < 0.01). In men, however, no significant association between disordered breathing and heart rates or arrhythmias was found. We conclude that serious arrhythmias are infrequent in unselected patients with coronary artery disease and mild to moderate sleep-disordered breathing. Disordered breathing in women is associated with higher heart rates and a higher occurrence of VPCs during sleep. [ABSTRACT FROM AUTHOR]

Published
2000
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