Search

Detailed information on the size of ice-nucleating particles (INPs) may be useful in source identification, modeling their transport in the atmosphere to improve climate predictions, and determining how effectively or ineffectively instrumentation used for quantifying INPs in the atmosphere captures the full INP population. In this study we report immersion-mode INP number concentrations as a function of size at six ground sites in North America and one in Europe using the micro-orifice uniform-deposit impactor droplet freezing technique (MOUDI-DFT), which combines particle size-segregation by inertial impaction and a microscope-based immersion freezing apparatus. The lowest INP number concentrations were observed at Arctic and alpine locations and the highest at suburban and agricultural locations, consistent with previous studies of INP concentrations in similar environments. We found that 91 ± 9, 79 ± 17, and 63 ± 21 % of INPs had an aerodynamic diameter > 1 µm at ice activation temperatures of −15, −20, and −25 °C, respectively, when averaging over all sampling locations. In addition, 62 ± 20, 55 ± 18, and 42 ± 17 % of INPs were in the coarse mode (> 2.5 µm) at ice activation temperatures of −15, −20, and −25 °C, respectively, when averaging over all sampling locations. These results are consistent with six out of the nine studies in the literature that have focused on the size distribution of INPs in the atmosphere. Taken together, these findings strongly suggest that supermicron and coarse-mode aerosol particles are a significant component of the INP population in many different ground-level environments. Further size-resolved studies of INPs as a function of altitude are required since the size distribution of INPs may be different at high altitudes due to size-dependent removal processes of atmospheric particles.

This study of 94 postmenopausal female smokers evaluated the effect of nicotine replacement therapy (NRT) and hormone therapy (HT) on change in weight, energy intake, and physical activity during 2 weeks of smoking abstinence. Women, stratified by current use of HT, were randomized to nicotine or placebo patch. After 2 weeks of abstinence, women on nicotine patch had significantly larger increases in total caloric and fat intake than women on placebo patch and a trend toward larger increases in carbohydrates (total and sweet). Conversely, the nicotine group had less weight gain, 0.47 kg, than the placebo group, 1.02 kg (F=10.31, p=0.002). No effects were observed for hormone therapy. It appears that in short-term smoking abstinence, postmenopausal women on NRT gain less weight than do women on placebo, in spite of consuming more calories. This may be beneficial in the critical first 1-2 weeks of tobacco cessation, especially in light of postmenopausal weight gain.

This study assessed the effect of short-term (2-week) smoking abstinence on weight gain, energy intake, and physical activity in 60 postmenopausal women. Participants were stratified by their use of hormone replacement therapy (HRT; currently taking/not taking) and then randomized to abstinence or continued smoking for 2 weeks. The 30 abstainers gained a mean of 1.28 kg, compared with a 0.54 kg loss for the 30 continued smokers (P=.002). The abstainers also reported a significantly greater increase than did the smokers in total kilocalorie and in carbohydrate consumption for both weeks. There were no changes in physical activity and HRT effect. These are the first published findings on caloric intake and weight gain during smoking abstinence in postmenopausal women-an understudied population in the smoking cessation literature.

This paper reports on the features of a reversing measurement system for the determination of the Bowen ratio. Ten-junction thermopiles are used to measure wet- and dry-bulb temperature differences, and a single thermocouple gives absolute wet-bulb temperature. The system is totally DC-powered and can be constructed to be portable. The performance of the system was evaluated in an experiment at the Petawawa National Forestry Institute, Chalk River, Ontario. The characteristics of the temperature gradients above a forest and a logged site are reported, along with the corresponding values of the Bowen ratio.