Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays

Average charged multiplicities have been measured separately in $b$, $c$ and light quark ($u,d,s$) events from $Z^0$ decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of $b$ and light quark events, and reconstructed charmed mesons were used to select $c$ quark events. We measured the charged multiplicities: $\bar{n}_{uds} = 20.21 \pm 0.10 (\rm{stat.})\pm 0.22(\rm{syst.})$, $\bar{n}_{c} = 21.28 \pm 0.46(\rm{stat.}) ^{+0.41}_{-0.36}(\rm{syst.})$ $\bar{n}_{b} = 23.14 \pm 0.10(\rm{stat.}) ^{+0.38}_{-0.37}(\rm{syst.})$, from which we derived the differences between the total average charged multiplicities of $c$ or $b$ quark events and light quark events: $\Delta \bar{n}_c = 1.07 \pm 0.47(\rm{stat.})^{+0.36}_{-0.30}(\rm{syst.})$ and $\Delta \bar{n}_b = 2.93 \pm 0.14(\rm{stat.})^{+0.30}_{-0.29}(\rm{syst.})$. We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters

EFFECT OF MICRONUTRIENT FORTIFIED BEVERAGE ON NUTRITIONAL ANAEMIA DURING PREGNANCY

Objective: To evaluate the efficacy of a multiple micronutrient fortified beveragecontaining eleven nutrients at physiological levels in prevention of anaemia andimproving iron and vitamin A status during pregnancy.Design: A randomised double blind placebo controlled study.Setting: Mpwapwa and Kongwa Districts in Dodoma Region of Tanzania.Subjects: Five hundred and seventy nine pregnant women were screened for entry intothe study and 439 women who met the study criteria were enrolled.Interventions: Study participants received either a fortified (F) or non-fortified (NF)orange flavoured drinks identical in appearance, provided in two self administeredservings per day for an eight week period.Main outcome measures: Comparison of haemoglobin (Hb), serum ferritin (SF) andserum retinol (SR) at baseline and follow up.Results: After eight weeks of supplementation, the F group (n=129) had a significantlyhigher Hb increase of 0.86g/dL compared to 0.45g/dL in the NF group (n=130) p<0.0001.Gestational age at entry into the study, moderated the effect on Hb of the fortifieddrink. Women at earlier gestational age upon entry, had a higher rise in Hb than womenof late gestational age (0.8g/dL versus 0.04 g/dL rise respectively, p=0.038, n=188). Therisk of being anaemic at the end of the study for those in the F group was reducedby 51% (RR=0.49, CI=0.28 to 0.85). Iron stores (by serum ferritin levels) increasedby 3µg/L in the F group (p=0.012) and a decrease of 2µg/L in the NF group (p=0.115).The follow up ferritin concentration depended on initial ferritin level. Regardless oftreatment group, serum retinol concentrations were significantly higher in mothers whohad delivered. Mothers who had adequate levels at entry benefited more from thesupplement than those with low levels (0.26 µmol/L versus no significant difference).Conclusions: The multiple micronutrient-fortified beverage given for eight weeks topregnant women improved their haemoglobin, serum ferritin and retinol status. Therisk for anaemia was also significantly reduced. The important predictors of Hb increaseat follow up were the fortified beverage, baseline Hb, serum retinol, baseline ferritinand gestational age at entry into study. Anthropological research showed that thebeverage was highly acceptable and well liked

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

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

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