Measurement of the Michel Parameters in Leptonic Tau Decays

The Michel parameters of the leptonic tau decays are measured using the OPAL detector at LEP. The Michel parameters are extracted from the energy spectra of the charged decay leptons and from their energy-energy correlations. A new method involving a global likelihood fit of Monte Carlo generated events with complete detector simulation and background treatment has been applied to the data recorded at center-of-mass energies close to sqrt(s) = M(Z) corresponding to an integrated luminosity of 155 pb-1 during the years 1990 to 1995. If e-mu universality is assumed and inferring the tau polarization from neutral current data, the measured Michel parameters are extracted. Limits on non-standard coupling constants and on the masses of new gauge bosons are obtained. The results are in agreement with the V-A prediction of the Standard Model.Comment: 32 pages, LaTeX, 9 eps figures included, submitted to the European Physical Journal

Multiple inflammasomes may regulate the interleukin-1-driven inflammation in protracted bacterial bronchitis

Protracted bacterial bronchitis (PBB) in young children is characterised by prolonged wet cough, prominent airway interleukin (IL)-1β expression and infection, often with nontypeable Haemophilus influenzae (NTHi). The mechanisms responsible for IL-1-driven inflammation in PBB are poorly understood. We hypothesised that the inflammation in PBB involves the NLRP3 and/or AIM2 inflammasome/IL-1β axis. Lung macrophages obtained from bronchoalveolar lavage (BAL), peripheral blood mononuclear cells (PBMCs), blood monocytes and monocyte-derived macrophages from patients with PBB and age-matched healthy controls were cultured in control medium or exposed to live NTHi. In healthy adult PBMCs, CD14+ monocytes contributed to 95% of total IL-1β-producing cells upon NTHi stimulation. Stimulation of PBB PBMCs with NTHi significantly increased IL-1β expression (p<0.001), but decreased NLRC4 expression (p<0.01). NTHi induced IL-1β secretion in PBMCs from both healthy controls and patients with recurrent PBB. This was inhibited by Z-YVAD-FMK (a caspase-1 selective inhibitor) and by MCC950 (a NLRP3 selective inhibitor). In PBB BAL macrophages inflammasome complexes were visualised as fluorescence specks of NLRP3 or AIM2 colocalised with cleaved caspase-1 and cleaved IL-1β. NTHi stimulation induced formation of specks of cleaved IL-1β, NLRP3 and AIM2 in PBMCs, blood monocytes and monocyte-derived macrophages. We conclude that both the NLRP3 and AIM2 inflammasomes probably drive the IL-1β-dominated inflammation in PBB.Alice C-H. Chen, Hai B. Tran, Yang Xi, Stephanie T. Yerkovich, Katherine J. Baines, Susan J. Pizzutto, Melanie Carroll, Avril A.B. Robertson, Matthew A. Cooper, Kate Schroder, Jodie L. Simpson, Peter G. Gibson, Greg Hodge, Ian B. Masters, Helen M. Buntain, Helen L. Petsky, Samantha J. Prime, Anne B. Chang, Sandra Hodge, and John W. Upha

Inclusive production of charged hadrons and Ks0K_{s}^{0} mesons in photon-photon collisions

The production of charged hadrons and K_s mesons in the collisions of quasi-real photons has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies of 161 and 172 GeV. The differential cross-sections as a function of the transverse momentum and the pseudorapidity of the charged hadrons and K_s mesons have been compared to the leading order Monte Carlo simulations of PHOJET and PYTHIA and to perturbative next-to-leading order (NLO) QCD calculations. The distributions have been measured in the range 10-125 GeV of the hadronic invariant mass W. By comparing the transverse momentum distribution of charged hadrons measured in gamma-gamma interactions with gamma-proton and meson-proton data we find evidence for hard photon interactions in addition to the purely hadronic photon interactions.The production of charged hadrons and K_s mesons in the collisions of quasi-real photons has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies of 161 and 172 GeV. The differential cross-sections as a function of the transverse momentum and the pseudorapidity of the charged hadrons and K_s mesons have been compared to the leading order Monte Carlo simulations of PHOJET and PYTHIA and to perturbative next-to-leading order (NLO) QCD calculations. The distributions have been measured in the range 10-125 GeV of the hadronic invariant mass W. By comparing the transverse momentum distribution of charged hadrons measured in gamma-gamma interactions with gamma-proton and meson-proton data we find evidence for hard photon interactions in addition to the purely hadronic photon interactions

A search for neutral Higgs bosons in the MSSM and models with two scalar field doublets

A search is described for the neutral Higgs bosons h^0 and A^0 predicted by models with two scalar field doublets and, in particular, the Minimal Supersymmetric Standard Model (MSSM). The search in the Z^0 h^0 and h^0 A^0 production channels is based on data corresponding to an integrated luminosity of 25 pb^{-1} from e^+e^- collisions at centre-of-mass energies between 130 and 172GeV collected with the OPAL detector at LEP. The observation of a number of candidates consistent with Standard Model background expectations is used in combination with earlier results from data collected at the Z^0 resonance to set limits on m_h and m_A in general models with two scalar field doublets and in the MSSM. For example, in the MSSM, for tan(beta) > 1, minimal and maximal scalar top quark mixing and soft SUSY-breaking masses of 1 TeV, the 95% confidence level limits m_h > 59.0 GeV and m_A > 59.5 GeV are obtained. For the first time, the MSSM parameter space is explored in a detailed scan.A search is described for the neutral Higgs bosons h^0 and A^0 predicted by models with two scalar field doublets and, in particular, the Minimal Supersymmetric Standard Model (MSSM). The search in the Z^0 h^0 and h^0 A^0 production channels is based on data corresponding to an integrated luminosity of 25 pb^{-1} from e^+e^- collisions at centre-of-mass energies between 130 and 172 GeV collected with the OPAL detector at LEP. The observation of a number of candidates consistent with Standard Model background expectations is used in combination with earlier results from data collected at the Z^0 resonance to set limits on m_h and m_A in general models with two scalar field doublets and in the MSSM. For example, in the MSSM, for tan(beta) > 1, minimal and maximal scalar top quark mixing and soft SUSY-breaking masses of 1 TeV, the 95% confidence level limits m_h > 59.0 GeV and m_A > 59.5 GeV are obtained. For the first time, the MSSM parameter space is explored in a detailed scan

Spin alignment of leading K∗(892)0K^{*}(892)^{0} mesons in hadronic Z0Z^0 decays

Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K ∗ (892) 0 mesons from hadronic Z 0 decays have been measured over the full range of K ∗ 0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x p values above 0.3, with the matrix element ϱ 00 rising to 0.66 ± 0.11 for x p > 0.7. The values of the real part of the off-diagonal element ϱ 1 - 1 are negative at large x p , with a weighted average value of −0.09 ± 0.03 for x p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the q q system from the Z 0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x p range. The K ∗ 0 fragmentation function has also been measured and the total rate determined to be 0.74 ± 0.02 ± 0.02 K ∗ (892) 0 mesons per hadronic Z 0 decay

A leadership competence utilization questionnaire for South African managers

Schroder has developed ten independent High Performance Leadership Competencies (HPLCs) that predict superior work unit performance in dynamic environments. Assessment centre technology was used for measuring HPLC's. On the basis of recent research, Schroder developed a 360° instrument, called the Competence Utilization Questionnaire (CUQ), to measure these competencies. The aim of this study was to adapt the CUQ for South African managers. Subjects were 128 middle and senior managers from three major business and utility organisations. Respondents (n = 658), who were either peers or work unit members of subjects, completed CUQ's regarding them. The questionnaire consisted of the ten Schroder competencies, and Contextual Sensitivity, a hypothesised South African competency. A true assumption-free, data-driven exploratory factor analytic study revealed seven well-defined common factors. These are Organisational Learning, Inspiration Building, Strategic Decision-making, Proactivity, Recognition for Development, Performance Feedback, and Contextual Sensitivity. Alpha reliability coefficients were above the 0.80 level, except Factor seven (0.74).Articl