Semileptonic decays of charmedD ± meson

Using the ACCMOR spectrometer equipped with a vertex telescope of high resolution silicon microstrip detectors 74 decays \(D^ + \to \bar K^{*0} (892)e^ + v_e \) (andcc.) withx _F <0.4 have been observed in 200 GeV π^? Be interactions. The cross-section forD ^± production, itsx _F -dependence in the central region and theD ^± lifetime have been measured.     

Hadronic ϕ production and the lund model for lowp T interactions

Experimental results on inclusive ? production are compared with the Lund model for lowp _T hadronic interactions. The data is based on a sample of 600,000 ? mesons in the kinematic rangep _T <1.0 (GeV/c)² and 0.0<x _F<0.4, produced in π^±,K ^±,p and \(\bar p\) Be interactions at 100 GeV/c and 120 GeV/c incident momentum. The Lund model reproduces the shapes of the longitudinal differential cross sections reasonably well, but the relative cross sections for incident, π,K andp show a discrepancy with the data.     

Effect of selenium on the Hg,Zn, Fe and Co content of yeast cells

The yeast cells, Saccharomyces cerevisiae, were exposed to Hg²⁺ ions (10^–4M) and SeO₂ (2·10^–4–10^–2M) or Se- methionine (2·10^–4M). Instrumental neutron activation analysis (INAA) was used to analyze changes in the Hg, Zn, Fe and Co levels in these cells. When the yeast was incubated in a medium containing 10^–3M and 10^–2M SeO₂, the Hg content of the yeast markedly increased. It was also found that the uptake of Se and Hg influenced the levels of Zn, Fe and Co found in the cells. While the presence of Se-methionine (Se-Met), SeO₂ or Hg²⁺ ions caused increases in the intracellular Zn levels, the combined presence of Hg²⁺ and SeO₂ and their assumed interaction, reduced the efficiency of Se for increasing the Zn content of yeast.     

A pressure-jump time-resolved X-ray diffraction study of cubic-cubic transition kinetics in monoolein

In the past two decades, the geometric pathways involved in the transformations between inverse bicontinuous cubic phases in amphiphilic systems have been extensively theoretically modeled. However, little experimental data exists on the cubic-cubic transformation in pure lipid systems. We have used pressure-jump time-resolved X-ray diffraction to investigate the transition between the gyroid QGII and double-diamond QDII phases in mixtures of 1-monoolein in 30 wt % water. We find for this system that the cubic-cubic transition occurs without any detectable intermediate structures. In addition, we have determined the kinetics of the transition, in both the forward and reverse directions, as a function of pressure-jump amplitude, temperature, and water content. A recently developed model allows (at least in principle) the calculation of the activation energy for lipid phase transitions from such data. The analysis is applicable only if kinetic reproducibility is achieved, at least within one sample, and achievement of such kinetic reproducibility is shown here, by carrying out prolonged pressure-cycling. The rate of transformation shows clear and consistent trends with pressure-jump amplitude, temperature, and water content, all of which are shown to be in agreement with the effect of the shift in the position of the cubic-cubic phase boundary following a change in the thermodynamic parameters.     

Bistable polarization switching in mutually coupled vertical-cavity surface-emitting lasers

We theoretically investigate the polarization-resolved dynamics of two vertical-cavity surface-emitting semiconductor lasers that are mutually coupled through coherent optical injection. We find a sequence of bistable polarization switchings that can be induced by changing either the coupling strength or the optical propagation phase. The successive polarization switchings are correlated with the creation of new compoundcavity modes when these parameters are continuously varied.