Why are experts not better in judging the danger of filmed traffic conflicts?

Earlier studies on the subject of subjective judgment of traffic conflicts showed that untrained subjects can reliably judge the dangerousness of filmed traffic conflicts. It was concluded that these judgements were based on a concept of dangerousness. In line with these findings two experiments were conducted. Experiment 1 tested the hypothesis that traffic experts (traffic engineers trained to evaluate and improve traffic safety) and lay people use the same concept of dangerousness when judging filmed conflicts. Experiment 2 investigated which aspects of the conflicts are considered by experts when making these judgements. The results show that (i) experts and lay people are equally reliable in judging traffic conflicts, (ii) experts base their judgement on the same concept of dangerousness, (iii) experts do not base their judgement on aspects that they themselves regard as important for the conflict, (iv) a weak relation is found between violations of traffic regulations and judgements of dangerousness.     

High-reliability GaAs-AlGaAs HBTs by MBE with Be base doping andInGaAs emitter contacts

The authors have developed a modified MBE growth process to produce high-gain n-p-n GaAs-AlGaAs heterojunction bipolar transistors (HBTs) with a mean time to failure (MTTF) of 1.5×10⁸ h at 125°C. Beryllium incorporation and diffusion are controlled through a combination of reduced substrate temperature and increased As/Ga flux ratio during MBE growth, resulting in extremely stable HBT profiles. The authors also demonstrate graded InGaAs surface layers with nonalloyed refractory metal contacts that significantly improve ohmic reliability compared to alloyed AuGe contacts. The ability to produce robust HBTs by MBE is critically important to this technology     

Relating blow moldability to large amplitude oscillatory shear behavior

The large amplitude oscillatory shear test has been used to discriminate subtle differences in nonlinear viscoelasticity between two high density polyethyene blow molding resins with different processability. Structural network theory was used to explain the subtle differences in terms of entanglement kinetics with remarkable accuracy. The resin with better shape retention characteristics in programmed parison blow molding was found to have a higher kinetic rate constant for molecular re-entanglement.     

On the use of tapered linearly chirped gratings asdispersion-induced distortion equalizers in SCM systems

We report on the use of tapered linearly chirped fiber gratings to equalize dispersion-induced distortion in long distance/broad-band subcarrier multiplexed (SCM) systems. Different apodization functions for the coupling factor of the fiber grating have been considered and their equalizing capability of fiber-induced distortion in a subcarrier system have been compared. The results of the theoretical analysis show that both harmonic and intermodulation distortions are significantly reduced when the equalizer parameters have been properly designed. Higher reduction of the nonlinear distortion is obtained when the length of the filter increases, even though a saturation effect on this reduction figure appears when the equalizer length is about four or five times its minimum value to achieve equalization, which is derived theoretically based on the SCM optical system parameters. The performance of a Tanh-type tapered linearly chirped grating equalizer on a realistic broadband SCM system is also considered. The results reveal that the dispersion-induced distortion can be neglected when the equalizer is employed     

Assessment of improvement of myocardial fatty acid uptake and function after revascularization using iodine-123-BMIPP

We investigated the effect of bioflavonoid quercetin on tyrosine phosphorylation and phospholipase D (PLD, EC 3.1.4.4) activation in rabbit peritoneal neutrophils stimulated by N-formylmethionyl-leucyl-phenylalanine (fMLP). The quercetin dose-dependently inhibited degranulation and superoxide production in fMLP-stimulated neutrophils. A strong inhibitory effect of quercetin on the tyrosine phosphorylation of several proteins (40, 42, 43, 45, 46 and 75 kDa) was observed when the neutrophils were pretreated with different concentrations of quercetin. Furthermore, quercetin inhibited mitogen activated protein kinase (MAP kinase) and PLD activation induced by fMLP in a dose-dependent manner. The reduction in PLD activity was 30% at 0.1 microM and 70% at 100 microM of quercetin. These results suggest that impairment of neutrophil functions by quercetin may be due, at least in part, to inhibition of tyrosine phosphorylation and PLD activation.