Optimized tomography methods for plasma emissivity reconstruction at the ASDEX Upgrade tokamak.

The soft X-ray (SXR) emission provides valuable insight into processes happening inside of high-temperature plasmas. A standard method for deriving the local emissivity profiles of the plasma from the line-of-sight integrals measured by pinhole cameras is the tomographic inversion. Such an inversion is challenging due to its ill-conditioned nature and because the reconstructed profiles depend not only on the quality of the measurements but also on the inversion algorithm used. This paper provides a detailed description of several tomography algorithms, which solve the inversion problem of Tikhonov regularization with linear computational complexity in the number of basis functions. The feasibility of combining these methods with the minimum Fisher information regularization is demonstrated, and various statistical methods for the optimal choice of the regularization parameter are investigated with emphasis on their reliability and robustness. Finally, the accuracy and the capability of the methods are demonstrated by reconstructions of experimental SXR profiles, featuring poloidal asymmetric impurity distributions as measured at the ASDEX Upgrade tokamak.

[Hip dislocation and fracture of the femoral head caused by low impact trauma]. / Hüftgelenkluxationsfraktur nach Niedrigenergietrauma.

Hip dislocations and particularly fractures of the femoral head are very rare injuries. Various therapy options are described. So far there has been consensus about the severity of the trauma which has causes this type of injury. This case study presents a type II Pipkin fracture. This specific "accident" was due to low impact trauma, which was previously considered to be insufficient to cause this type of injury. We report on the diagnostic and therapeutic measures and compare this procedure with information from the literature.

Ecology of Arcobacter species in chicken rearing and processing.

AIMS: To investigate whether Arcobacter spp. colonize the poultry-rearing environment or whether they are contaminants acquired during transportation and/or from the processing plant. METHODS AND RESULTS: Samples were collected on poultry farms and in the processing plant during slaughter and dressing. Two cultural methods of detection were used. Isolates were identified to species level using a multiplex-polymerase chain reaction (m-PCR) method, either on the initial suspensions, or after enrichment, or on pure cultures of isolates. Of the 62 samples examined from poultry farms, arcobacters were found only outside the rearing sheds (in effluent sludge and stagnant water). Thirty-four samples were examined from the processing plant and 26 were positive for arcobacters. All the isolates were Arcobacter butzleri. Arcobacters were not found in any sample by direct plating nor by m-PCR on the initial suspensions, thus it was concluded that numbers were very low. CONCLUSIONS: Arcobacter spp. were not found in samples from the live birds and their immediate environment, but A. butzleri was found in effluent sludge and stagnant water outside the rearing sheds. However, A. butzleri is common in poultry abattoirs, and it appears that poultry carcasses are contaminated during processing. SIGNIFICANCE AND IMPACT OF THE STUDY: Arcobacters are not found inside poultry-rearing sheds, but are contaminants in the processing environment.

Reaching high poloidal beta at Greenwald density with internal transport barrier close to full noninductive current drive.

In the ASDEX Upgrade tokamak, high poloidal beta up to beta(pol) = 3 at the Greenwald density with H-mode confinement has been reached. Because of the high beta, the plasma current is driven almost fully noninductively, consisting of 51% bootstrap and 43% neutral beam driven current. To reach these conditions the discharge is operated at low plasma current ( I(P) = 400 kA) and high neutral beam heating power ( P(NBI) = 10 MW). The discharge combines an edge (H mode) and internal transport barrier at high densities without confinement-limiting MHD activities. The extrapolation to higher plasma currents may offer a promising way for an advanced scenario based fusion reactor.

High-confinement regime at high beta(N) values due to a changed behavior of the neoclassical tearing modes.

High confinement [with H = 1, ITERH- 98( y,2)] at beta(N) approximately 2.3 has been found in ASDEX Upgrade discharges with existing (m,n) = (3,2) neoclassical tearing modes (NTMs). The reason for the high confinement at high beta(N) values is a transition of the NTMs into the so-called frequently interrupted regime. In this regime, the NTM growth is frequently interrupted by sudden drops in amplitude. Because of the long NTM growth time, the resulting averaged NTM amplitude remains much smaller than the corresponding saturated value. As this behavior with the beneficial effect on energy confinement has been confirmed at JET, such a high confinement regime at beta(N)>2 might also be expected for ITER.