Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

The immune response of foetal calves

The immunological response of foetal calves to tetanus toxoid was investigated. Emphasis was placed on foetal immunocompetence and how this related to responses seen in adult cattle. The establishment of indwelling cannulas in the efferent prescapular lymphatic ducts and superficial veins of foetal calves allowed continual monitoring of cellular and humoral changes in efferent lymph and peripheral blood. Foetal calves from 195 to 253 days gestational age had the capacity to mount cell-mediated and humoral immune responses of similar character and magnitude as adult cattle to tetanus toxoid. Intravenous and subcutaneous routes of challenge with tetanus toxoid resulted in specific antibody production which peaked 26 to 31 days after vaccination. Significant tetanus toxoid-stimulated lymphocyte proliferation was present 4 to 6 weeks after vaccination with tetanus toxoid in both a foetus and an adult. After antigenic challenge lymphocytes remained the predominant cell type in efferent prescapular lymph of foetuses and cows while at the same time a marked shift to the left, characterised by band neutrophils and neutrophilic metamyelocytes occurred in peripheral blood. Lymph flow rate increased and cell concentration decreased after antigenic challenge

The proliferative responses of lymphocytes from foetal calves and adult cattle

This paper describes the proliferative responses of prescapular lymph lymphocytes and peripheral blood lymphocytes of foetal calves compared with cells of similar origin from adult cattle. Lymph lymphocytes were collected continuously by means of cannulation of efferent lymphatic ducts of the prescapular lymph node of foetal calves and adult cattle. Peripheral blood lymphocytes were collected from the foetus by means of cannulation of superficial veins of the foetus or of the umbilical vessels and from the jugular vein of adults. Foetal lymphocytes in one-way mixed lymphocyte culture stimulated and responded as well as adult lymphocytes. Foetal cells stimulated and responded more to cells from unrelated animals than to cells from their dam. Lymph lymphocytes from foetal calves between 188 and 253 days of gestation proliferated as well as adult lymphocytes and at a high level after stimulation with concanavalin A, phytohaemagglutinin and pokeweed mitogen. Response to stimulation with lipopolysaccharide, soybean agglutinin and wheat-germ agglutinin was variable but generally low and within the same range recorded by adult cells. Proliferation by foetal and adult whole-blood cultures was on occasions as high as that recorded by separated lymphocytes, even though fewer lymphocytes were initially present in the whole-blood cultures. Foetal lymph lymphocytes exhibited lower proliferative responses in autologous lymph plasma than in foetal calf serum or pooled foetal lymph plasma. There was no consistent depression of proliferation by culture medium supplements from pregnant animals. Rabbit serum consistently abrogated responses. Fetuin at final concentrations of greater than 2.5 mg/ml significantly depressed proliferation in foetal and adult lymphocytes from efferent lymph and peripheral blood

The cellular response of lambs to Brucella ovis before and after birth

The immunological response of lambs to Brucella ovis before and after birth was investigated. The establishment of indwelling cannulas in the efferent prescapular lymphatic ducts of foetal lambs allowed continual monitoring of the immune response of a single lymph node. Foetal lambs in the last trimester of pregnancy were shown to mount a strong cell-mediated immune response to B. ovis. Lymphocytes from the challenged lymph node stimulated with B. ovis in vitro usually first reacted significantly and had highest [3H]-thymidine incorporation between 4 and 6 days after primary and secondary challenge, whereas, lymphocytes from the unchallenged node did not exhibit significant [3H]-thymidine incorporation until some 24 h later. Lymphocytes from these lambs challenged as foetuses still exhibited significant [3H]-thymidine incorporation in response to B. ovis for 4 to 5 months after birth. The proportion of surface immunoglobulin-positive cells in efferent prescapular lymph of unchallenged lambs ranged from 0.5 to 2.0% but after B. ovis challenge this proportion ranged from 2.7 to 8.7% between 4 to 6 days after challenge. By 9 to 12 days after challenge, the proportion had declined to pre-challenge values