This paper first describes a conceptual model for hardening. Then the paper describes important methodological distinctions (quit attempts vs. ability to remain abstinent as indicators, measures of hardening per se vs. measures of causes of hardening, and dependence measures that do vs. do not include cigarettes per day (cigs/day).) After this commentary, the paper reviews data from prior reviews and new searches for studies on one type of hardening: the decreasing ability to quit due to increasing nicotine dependence. Overall, all four studies
of the general population of smokers found no evidence of decreased ability to quit; however, both secondary analyses of treatment-seeking smokers found quit rates were decreasing over time. Cigs/day BIX-01294 and time-to-first cigarette measures of dependence did not increase over time; however, two studies found that DSM-defined dependence appeared to be increasing over time. Although these data suggest hardening may be occurring in treatment seekers but not in the general population of smokers, this conclusion may be premature given learn more the small number of data sets and indirect measures of quit success and dependence in the data sets. Future studies should include questions about quit attempts, ability to abstain, treatment use, and multi-item dependence measures. (C) 2011 Elsevier Ireland Ltd. All rights reserved.”
“Human
activities have greatly modified predator-prey dynamics within seabird communities by favouring a rapid increase in density of large predatory gulls. To counteract
such a subsidized growth, conservation agencies NSC23766 perform massive random culling programs, which generally fail to restore the original predator-prey relationship. We used long-term individual-based information to evaluate the effects of a selective culling of a top seabird predator, the yellow-legged gull (Larus michahellis), on the predatory pressure, survival and reproductive success probabilities of a secondary prey, the vulnerable European storm-petrel (Hydrobates pelagicus). The selective removal of only 16 gulls in 3 years led to a reduction of ca. 65% in the number of petrels killed, and to a relative increase in their survival and breeding success probabilities of 16% and 23%, respectively. Our results show that only a few specialises predators were responsible for the bulk of the impact on a secondary prey and that the removal of those specialised individuals was an effective and efficient way to improve prey demographic parameters. (C) 2008 Elsevier Ltd. All rights reserved.”
“Background: The purpose of this study was to describe the incidence of serious bacterial infections in febrile outpatient pediatric kidney transplant recipients and to assess the utility of using white blood cell indices to identify patients at low risk for bacteremia.