Serological profiles in nursery piglets colonized with Staphylococcus aureus

At present, the immune response of pigs in relation to Staphylococcus aureus carriage is poorly understood. This study aimed at investigating the dynamics of the anti-staphylococcal humoral immune response in methicillin-susceptible S. aureus (MSSA)-positive piglets and at assessing the effect of the experimental introduction of a methicillin-resistant S. aureus (MRSA) Sequence Type (ST) 398 strain. Therefore, serum samples were collected at different times from 31 weaned piglets originating from four different sows. Twenty-four out of the 31 piglets were challenged with MRSA ST398. The serum samples were analysed for IgG antibodies to 39 S. aureus antigens, using a multiplex bead-based assay (xMAP technology, Luminex Corporation). Though antibody responses showed broad inter-individual variability, serological results appeared to be clustered by litter of origin. For most antigens, an age-related response was observed with an apparent increase in antibody titres directed against staphylococcal microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), which have been shown to play a role in S. aureus colonization. In most animals, antibody titres directed against staphylococcal toxins or immune-modulating proteins decreased with age, possibly reflecting absence of bacterial invasion. The introduction of MRSA ST398 did not elicit a significant humoral immune reaction. This study describes, for the first time, the humoral immune response in weaned pigs colonized with S. aureus

Impact of minority concentration on fundamental (H)D ICRF heating performance in JET-ILW

ITER will start its operation with non-activated hydrogen and helium plasmas at a reduced magnetic field of B-0 = 2.65 T. In hydrogen plasmas, the two ion cyclotron resonance frequency (ICRF) heating schemes available for central plasma heating (fundamental H majority and 2nd harmonic He-3 minority ICRF heating) are likely to suffer from relatively low RF wave absorption, as suggested by numerical modelling and confirmed by previous JET experiments conducted in conditions similar to those expected in ITER's initial phase. With He-4 plasmas, the commonly adopted fundamental H minority heating scheme will be used and its performance is expected to be much better. However, one important question that remains to be answered is whether increased levels of hydrogen (due to e. g. H pellet injection) jeopardize the high performance usually observed with this heating scheme, in particular in a full-metal environment. Recent JET experiments performed with the ITER-likewall shed some light onto this question and the main results concerning ICRF heating performance in L-mode discharges are summarized here

Experimental Study of Convective Cells and RF Sheaths Ex- cited by a Fast Wave Antenna in the LAPD

C

Effect of toroidal field ripple on plasma rotation in JET

Dedicated experiments on TF ripple effects on the performance of tokamak plasmas have been carried out at JET. The TF ripple was found to have a profound effect on the plasma rotation. The central Mach number, M, defined as the ratio of the rotation velocity and the thermal velocity, was found to drop as a function of TF ripple amplitude (3) from an average value of M = 0.40-0.55 for operations at the standard JET ripple of 6 = 0.08% to M = 0.25-0.40 for 6 = 0.5% and M = 0.1-0.3 for delta = 1%. TF ripple effects should be considered when estimating the plasma rotation in ITER. With standard co-current injection of neutral beam injection (NBI), plasmas were found to rotate in the co-current direction. However, for higher TF ripple amplitudes (delta similar to 1%) an area of counter rotation developed at the edge of the plasma, while the core kept its co-rotation. The edge counter rotation was found to depend, besides on the TF ripple amplitude, on the edge temperature. The observed reduction of toroidal plasma rotation with increasing TF ripple could partly be explained by TF ripple induced losses of energetic ions, injected by NBI. However, the calculated torque due to these losses was insufficient to explain the observed counter rotation and its scaling with edge parameters. It is suggested that additional TF ripple induced losses of thermal ions contribute to this effect

Fundamental cyclotron 3He minority ICRF heating experiments in H plasmas in JET in presence of the ILW

Efficient plasma heating schemes are a prerequisite for reaching fusion relevant temperatures in fusion machines. On the road to reaching ignition, non-activated scenarios - such as (3He

Evaluatie en waardering van de archeologische sites Rooiveld-Papenvijvers(Oostkamp, provincie West-Vlaanderen)

Dit rapport beschrijft de resultaten van het waarderend onderzoek op de archeologische sites Rooiveld-Papenvijvers in Oostkamp (West-Vlaanderen). De oudste sporen van menselijke activiteit in dit gebied gaan terug tot het mesolithicum. De bewoning tijdens het neolithicum is goed gedocumenteerd. Naast de opgegraven nederzetting te Waardamme Vijvers, leverde het proefsleuvenonderzoek te Papenvijvers een finaal-neolithische site (3de millennium cal BC). Verder leverden de beperkte prospecties op verschillende plaatsen, waaronder Oostkamp Nieuwenhove en Hertsberge Papevijvers, lithische artefacten op die naar alle waarschijnlijkheid tot een niet nader te bepalen fase van het neolithicum behoren. Deze situatie is vrij uniek voor Vlaanderen. Neolithische bewoning in de zandige delen van Vlaanderen ontbrak tot nog toe vrijwel, met uitzondering van enkele graven van de Klokbekercultuur. De opgraving te Waardamme Vijvers is bijzonder vanwege de ontdekking van de eerste en vooralsnog enige huisplattegrond uit het neolithicum in Vlaanderen. Sporen uit de bronstijd zijn dankzij de luchtfotografie heel talrijk in het gebied. Het desktop onderzoek leverde in totaal een negental cirkelvormige structuren op die naar alle waarschijnlijkheid mogen geïnterpreteerd worden als resten van grafheuvels uit de vroege en midden-bronstijd. Het is ook duidelijk dat de regio in de bronstijd bewoond was, o.a. door de opgraving op de site Waardamme Vijvers. Voor de ijzertijd is de situatie vermoedelijk gelijklopend. De enige nederzetting die uit deze periode werd aangetroffen komt eveneens uit de opgraving in Waardamme Vijvers. Voor de Romeinse periode beschikken we slechts over de sporen van een grafveld op Waardamme Vijvers en keramiekvondsten. Latere periodes zijn alleen via cartografische bronnen gedocumenteerd. Het rapport eindigt met aanbevelingen voor verder onderzoek en beheer van dit gebied

N=2 ICRH of H majority plasmas in JET-ILW

Heating single ion species plasmas with ICRF is a challenging task: Fundamental ion cyclotron heating (w = w(ci)) suffers from the adverse polarization of the RF electric fields near the majority cyclotron resonance while second harmonic heating (w =2w(ci)) typically requires pre-heating of the plasma ions to become efficient. Recently, w =2wci ICRF heating was tested in JET-ILW hydrogen plasmas in the absence of neutral beam injection (L-mode). Despite the lack of pre-heating, up to 6MW of ICRF power were coupled to the plasma leading to a transition to H-mode for P-ICRH>5MW in most discharges. Heating efficiencies between 0.65-0.85 were achieved as a combination of the low magnetic field adopted (enhanced finite Larmor radius effects) and the deliberate slow rise of the ICRF power, allowing time for a fast ion population to gradually build-up leading to a systematic increase of the wave absorptivity. Although fast ion tails are a common feature of harmonic ICRF heating, the N=2 majority heating features moderate tail energies (<500keV) except at very low plasma densities (n(e0)<3x10(19)/m(3)), where fast H tails in the MeV range developed and fast ion losses became significant, leading to enhanced plasma wall interaction. The main results of these experiments will be reported

Hydrogen minority ion cyclotron resonance heating in presence of the iter-like wall in jet

The most recent JET campaign has focused on characterizing operation with the "ITER-like" wall. One of the questions that needed to be answered is whether the auxiliary heating methods do not lead to unacceptably high levels of impurity influx, preventing fusion-relevant operation. In view of its high single pass absorption, hydrogen minority fundamental cyclotron heating in a deuterium plasma was chosen as the reference wave heating scheme in the ion cyclotron domain of frequencies. The present paper discusses the plasma behavior as a function of the minority concentration X[H] in L-mode with up to 4MW of RF power. It was found that the tungsten concentration decreases by a factor of 4 when the minority concentration is increased from X[H] ≈ 5% to X[H] % 20% and that it remains at a similar level when X[H] is further increased to 30%; a monotonic decrease in Beryllium emission is simultaneously observed. The radiated power drops by a factor of 2 and reaches a minimum at X[H] ≈ 20%. It is discussed that poor single pass absorption at too high minority concentrations ultimately tailors the avoidance of the RF induced impurity influx. The edge density being different for different minority concentrations, it is argued that the impact ICRH has on the fate of heavy ions is not only a result of core (wave and transport) physics but also of edge dynamics and fueling