Transitions in smoking status over time in a population-based panel study of smokers.

INTRODUCTION: Few studies have examined the transitions of smokers in the general population through multiple periods of daily, occasional smoking, or abstinence over time. Transitions from daily to occasional smoking are particularly of interest as these may be steps toward cessation. METHODS: The Ontario Tobacco Survey panel study followed 4,355 baseline smokers, semiannually for up to 3 years. Probabilities of all possible changes in smoking status more than 6 months were estimated using 13,000 repeated measures observations generated from sets of 3 consecutive interviews (n = 9,932 daily smokers, 1,245 occasion smokers, and 1,823 abstinent for at least 30 days, at Time 1). RESULTS: For initial daily smokers, an estimated 83% remained daily smokers more than 2 follow-ups. The majority of those who had been abstinent for 30 days at 1 interview, were also former smokers at the following interview. In contrast, occasional smoking status was unstable and future smoking status was dependent upon smoking history and subjective dependence. Among daily smokers who became occasional smokers 6 months later, an estimated 20% became a former smoker, at the next interview, but 50% returned to daily smoking. Daily, turned occasional smokers who rebounded back to daily smoking were more likely to describe themselves as addicted at Time 1. Continuing occasional smokers were somewhat less likely to intend to quit, or have tried, despite considering themselves less addicted. CONCLUSIONS: Reducing to occasional smoking can be a stepping stone toward cessation but entails a greater risk of return to daily smoking, compared with complete abstinence.

Cascadability properties of MZI-SOA-based all-optical 3R regenerators for RZ-DPSK signals.

We experimentally demonstrate 50 cascaded all-optical 3R regenerators over a 1,000 km transmission distance for 10-Gb/s return-to-zero differential phase-shift keying (RZ-DPSK) signals. The regenerator consists of integrated Mach-Zehnder interferometer (MZI) semiconductor optical amplifier (SOA) based wavelength converters. Regenerative properties and tolerance to pattern dependent effects have been studied in terms of Q-factor measurement, and error free operation with input OSNR of 20 dB/0.1 nm has also been demonstrated.

Monolithically integrated dual-quadrature receiver on InP with 30 nm tunable local oscillator.

We demonstrate a monolithically integrated dual-quadrature coherent receiver with greater than 30 nm widely-tunable SG-DBR local oscillator, signal input SOAs, a 90° optical hybrid and four 10 GHz photodetectors. With 20 Gb/s NRZ-QPSK, we demonstrate a required OSNR of 10 dB for a BER of 10(-3) at four different wavelengths.

Vendor compliance with Ontario's tobacco point of sale legislation.

OBJECTIVE: On May 31, 2006, Ontario joined a small group of international jurisdictions to implement legislative restrictions on tobacco point of sale promotions. This study compares the presence of point of sale promotions in the retail tobacco environment from three surveys: one prior to and two following implementation of the legislation. METHOD: Approximately 1,575 tobacco vendors were randomly selected for each survey. Each regionally-stratified sample included equal numbers of tobacco vendors categorized into four trade classes: chain convenience, independent convenience and discount, gas stations, and grocery. Data regarding the six restricted point of sale promotions were collected using standardized protocols and inspection forms. Weighted estimates and 95% confidence intervals were produced at the provincial, regional and vendor trade class level using the bootstrap method for estimating variance. RESULTS: At baseline, the proportion of tobacco vendors who did not engage in each of the six restricted point of sale promotions ranged from 41% to 88%. Within four months following implementation of the legislation, compliance with each of the six restricted point of sale promotions exceeded 95%. Similar levels of compliance were observed one year later. Grocery stores had the fewest point of sale promotions displayed at baseline. Compliance rates did not differ across vendor trade classes at either follow-up survey. Point of sale promotions did not differ across regions in any of the three surveys. CONCLUSION: Within a short period of time, a high level of compliance with six restricted point of sale promotions was achieved.