Emerging dominance of summer rainfall driving High Arctic terrestrial-aquatic connectivity.

Hydrological transformations induced by climate warming are causing Arctic annual fluvial energy to shift from skewed (snowmelt-dominated) to multimodal (snowmelt- and rainfall-dominated) distributions. We integrated decade-long hydrometeorological and biogeochemical data from the High Arctic to show that shifts in the timing and magnitude of annual discharge patterns and stream power budgets are causing Arctic material transfer regimes to undergo fundamental changes. Increased late summer rainfall enhanced terrestrial-aquatic connectivity for dissolved and particulate material fluxes. Permafrost disturbances (<3% of the watersheds' areal extent) reduced watershed-scale dissolved organic carbon export, offsetting concurrent increased export in undisturbed watersheds. To overcome the watersheds' buffering capacity for transferring particulate material (30 ± 9 Watt), rainfall events had to increase by an order of magnitude, indicating the landscape is primed for accelerated geomorphological change when future rainfall magnitudes and consequent pluvial responses exceed the current buffering capacity of the terrestrial-aquatic continuum.

Differential impact of thermal and physical permafrost disturbances on High Arctic dissolved and particulate fluvial fluxes.

Climate warming and changing precipitation patterns have thermally (active layer deepening) and physically (permafrost-thaw related mass movements) disturbed permafrost-underlain watersheds across much of the Arctic, increasing the transfer of dissolved and particulate material from terrestrial to aquatic ecosystems. We examined the multiyear (2006-2017) impact of thermal and physical permafrost disturbances on all of the major components of fluvial flux. Thermal disturbances increased the flux of dissolved organic carbon (DOC), but localized physical disturbances decreased multiyear DOC flux. Physical disturbances increased major ion and suspended sediment flux, which remained elevated a decade after disturbance, and changed carbon export from a DOC to a particulate organic carbon (POC) dominated system. As the magnitude and frequency of physical permafrost disturbance intensifies in response to Arctic climate change, disturbances will become an increasingly important mechanism to deliver POC from terrestrial to aquatic ecosystems. Although nival runoff remained the primary hydrological driver, the importance of pluvial runoff as driver of fluvial flux increased following both thermal and physical permafrost disturbance. We conclude the transition from a nival-dominated fluvial regime to a regime where rainfall runoff is proportionately more important will be a likely tipping point to accelerated High Arctic change.

The Joule heating problem in silver nanowire transparent electrodes.

Silver nanowire transparent electrodes have shown considerable potential to replace conventional transparent conductive materials. However, in this report we show that Joule heating is a unique and serious problem with these electrodes. When conducting current densities encountered in organic solar cells, the average surface temperature of indium tin oxide (ITO) and silver nanowire electrodes, both with sheet resistances of 60 ohms/square, remains below 35 °C. However, in contrast to ITO, the temperature in the nanowire electrode is very non-uniform, with some localized points reaching temperatures above 250 °C. These hotspots accelerate nanowire degradation, leading to electrode failure after 5 days of continuous current flow. We show that graphene, a commonly used passivation layer for these electrodes, slows nanowire degradation and creates a more uniform surface temperature under current flow. However, the graphene does not prevent Joule heating in the nanowires and local points of high temperature ultimately shift the failure mechanism from nanowire degradation to melting of the underlying plastic substrate. In this paper, surface temperature mapping, lifetime testing under current flow, post-mortem analysis, and modelling illuminate the behaviour and failure mechanisms of nanowires under extended current flow and provide guidelines for managing Joule heating.

Predicting smoking cessation with self-reported measures of nicotine dependence: FTQ, FTND, and HSI.

In two independent studies, we explored the usefulness of three self-report measures of tobacco dependence--the Fagerström Tolerance Questionnaire (FTQ), the Fagerström Test for Nicotine Dependence (FTND), and the Heavy Smoking Index (HSI). The FTND is a revised version of the FTQ. The HSI is identical to a two-question subset of the FTND. Study 1 involved 932 participants in a seven-session, five-week, group smoking cessation program, and it looked at the ability of these self-report tests to predict expired air carbon monoxide (i.e., heaviness of smoking) at beginning of treatment and cessation at end of treatment. Study 2 involved 1877 participants in a self-help smoking cessation program, and it looked at the prediction of cessation at 16-month follow-up. All tests made statistically reliable predictions of smoking cessation, but generally accounted for little variance (about 1%). In Study 1, the test scores were associated positively with carbon monoxide levels. The shorter (six vs. eight questions), more reliable FTND is to be preferred to the FTQ; and the HSI (two questions) works as well as the FTND. Evidence is presented that suggests that samples of high-scoring smokers will not be well differentiated from the mid-range to the high-end of the scores.

Patterns of alcohol, cigarette, and caffeine and other drug use in two drug abusing populations.

Relationships were explored among the frequencies of use of various drugs by a sample of drug-abusing clients of the Addiction Research Foundation (ARF) in Toronto and by drug abusers volunteering to participate in research at the Addiction Research Center (ARC) in Baltimore. The two groups of drug-abusing individuals differed in a number of characteristics. Those from ARF were admitted primarily for diagnosis and possible treatment for alcohol and non-opioid drug problems, whereas those from the ARC were admitted for participation in research on other drugs of abuse, primarily involving opioids. Patterns of use of certain drugs tended to covary in both groups. Of particular interest was the finding that severity of alcoholism was directly related to various measures of tobacco and caffeinated beverage use. In contrast, there was little correlation between the frequency of use among other drugs of abuse (e.g., heroin, cannabis, glue) and the use of tobacco and caffeine. These findings suggest that dependence on nicotine, caffeine, and alcohol may be governed by the same factors and possibly should be considered jointly in the treatment of alcoholic persons. Frequency of use of other drugs examined may be controlled by other factors than those which determine level of use of tobacco and caffeine.

Prospects for smoking treatment in individuals seeking treatment for alcohol and other drug problems.

Alcohol and drug using clients of the Addiction Research Foundation were asked about their interest in receiving treatment for cigarette smoking. Forty-six percent said that they were "moderately" to "very much" interested in attending a treatment program if it were available. Despite a consistent preference for receiving smoking treatment after their alcohol or drug problem was treated, there was moderate interest in receiving smoking treatment during the alcohol or drug treatment among those who were very interested in receiving smoking treatment in general. Seventy-one percent reported that it would be "as difficult" or "more difficult" to give up cigarettes than the drug or alcohol which brought them to the hospital for treatment. The importance of treating smoking in alcohol and drug using clients is discussed.

Prevalence of the misuse of ultra-low-tar cigarettes by blocking filter vents.

Evidence from tar-stain patterns in 135 cigarette filters discarded in ashtrays in public areas of shopping malls was used to estimate the prevalence of behaviorally blocked air dilution vents in ultra-low-yield cigarettes. Nineteen per cent (+/- 4, standard errors of the mean) of the filters had been blocked extremely, 39 per cent (+/- 5 SEM) had been blocked to some degree, and 42 per cent (+/- 5 SEM) had not been blocked at all. Smokers, health practitioners, and researchers need to be warned of the risks of vent blocking.

A color-matching technique for monitoring tar/nicotine yields to smokers.

We describe a technique that enables individuals to detect the number of puffs taken on a filter cigarette by comparing the "color" of the spent filter to a color scale that simulates the appearance of filters exposed to low-, standard-, or high-yield smoking-machine regimens. Average ratings of filters by 11 subjects correlated almost perfectly with the number of standard puffs to which the filters had been exposed. (Am J Public Health 1982; 72:597-599.)

Early effects of quitting smoking.

Heart rate, hand tremor, skin temperature, eating, and craving for cigarettes were examined in 19 smokers who quit for 1 day. Measures of heart rate and hand tremor were lower during abstinence; craving seemed greater, skin temperature was higher, and there was more eating, particularly snacking, but no shift in preference towards sweet foods. Quitting brings about profound changes in a smoker's physiology and behaviour, even during the first day. Anticipation of these changes could help would-be quitters, and those who advise them.

The misuse of 'less-hazardous' cigarettes and its detection: hole-blocking of ventilated filters.

Smokers of low-yield, ventilated-filter cigarettes sometimes defeat the purpose of the smoke-dilution holes by occluding them with fingers, lips, or tape. Blocking the holes is shown to have large effects on the delivery by these cigarettes of toxic products (nicotine, tar, and carbon monoxide). Techniques for detecting this misuse of "less hazardous" cigarettes are discussed, with particular emphasis on the distinctive signs of hole-blocking which are left in the spent filters.