Limits on the production of scalar leptoquarks from Z (0) decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)

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

Alkali metal cation-pi interactions stabilized solely by [M{N(SiMe3)(2)}(3)](-) anions (M = Mg or Zn): The competing influence of alkali metal center dot center dot center dot C(Me) agostic interactions

A series of [K(ar)(2)](+) and [Rb(toluene)(3)](+) cations (ar = benzene, toluene, o-xylene, or p-xylene) has been synthesized and crystallized in the presence of [M{N(SiMe3)(2)}(3)](-) anions (M = Mg or Zn). In the solid state all form either extended supermolecular, dimeric or supramolecular, polymeric structures. Only [K(toluene)(2)][Mg{N(SiMe3)(2)}(3)] was found to exist as both suprastructural isomers. Introducing cyclopentadienyl to the system gave a similar zincate with the unusual [K2CP](+) cation. The absence of any traditional Lewis bases facilitates' short metal-to-arene contact distances and makes these species excellent candidates for the study of alkali metal cation-pi interactions. It is shown that K-pi interactions and to a lesser extent Rb-pi interactions are heavily influenced by the number and nature of agostic methyl interactions, especially when the electron-donating ability of these is maximized by adoption of near-linear geometries. These features combine so that the weakest potassium-to-arene interaction observed is that with benzene

Estágios imaturos de Sabulodes caberata caberata Guenée, 1857 e Sabulodes exhonorata Guenée, 1857 (Lepidoptera, Geometridae, Ennominae)1

São apresentados dados sobre o ciclo de vida e a morfologia dos estágios imaturos de Sabulodes caberata caberata Guenée, 1857 e Sabulodes exhonorata Guenée, 1857, ambas coletadas em São Carlos, São Paulo, Brasil. As larvas se alimentam de Eucalyptus sp. Os estágios imaturos são semelhantes em geral, nas duas espécies, mas existem vários caracteres distintivos.<br>Data are presented on the life cycle and morphology of the immature stages of Sabulodes caberata caberata Guenée, 1857 and Sabulodes exhonorata Guenée, 1857, both collected in São Carlos, São Paulo, Brazil. The larvae feed on Eucalyptus sp. The immature stages in general appearance are similar between the two species, but there are various distinctive characters