For focused pulses of light in isotropic nonlinear media, third-harmonic generation can be strongly affected by group-velocity mismatch between the fundamental and third-harmonic. There is a characteristic time determined by the group-velocity mismatch and the Rayleigh range of the focused pulse. The dynamics depend on two dimensionless quantities, namely the ratio of the characteristic time to...

We assume a Boolean parallel system with exponentially distributed component failure times. In order to maximize the lifetime of the system we consider a repairman with Erlang-k distributed repair time. By extending the classical exponential case k = 1 to k ≥ 2 different repair semantics arise in this context. In the case of restart repair semantics we show that a repairman should have few Erla...

Abstract -We estimate the availability, reliability, and mean transaction time (response time) for repairable database configurations, centralized or distributed, in which each service component is continuously available for repair. Reliability, the probability that the entire transaction can execute properly without failure, is computed as a function of mean time to failure (MTTF) and mean tim...

The temporal properties of a sample of 498 bright gamma-ray bursts (GRBs) with durations between 0.05 s and 674 s were analysed. The large range in duration (T90) is accompanied by a similarly large range in the median values of the pulse timing properties including rise time, fall time, FWHM and separation between the pulses. Four timing diagrams relating these pulse properties to T90 are pres...

PURPOSE To investigate the effect of lens density on liquefaction time by using liquefaction device (AquaLase, Alcon Laboratories, TX, U.S.A.). METHODS Cataract surgery using AquaLase was performed on 47 eyes. With a Scheimpflug camera, the density and thickness of lens were measured in eye of each patient preoperatively. During surgery, liquefaction time and total number of pulses were recor...

If γ-ray bursts are at cosmological distances, then not only their constituent pulses but also the intervals between pulses should be time-dilated. Unlike time-dilation measures of pulse emission, intervals would appear to require negligible correction for redshift of narrower temporal structure from higher energy into the band of observation. However, stretching of pulse intervals is inherentl...