"Best fit" framework synthesis: refining the method

Background Following publication of the first worked example of the “best fit” method of evidence synthesis for the systematic review of qualitative evidence in this journal, the originators of the method identified a need to specify more fully some aspects of this particular derivative of framework synthesis. Methods and Results We therefore present a second such worked example in which all techniques are defined and explained, and their appropriateness is assessed. Specified features of the method include the development of new techniques to identify theories in a systematic manner; the creation of an a priori framework for the synthesis; and the “testing” of the synthesis. An innovative combination of existing methods of quality assessment, analysis and synthesis is used to complete the process. This second worked example was a qualitative evidence synthesis of employees’ views of workplace smoking cessation interventions, in which the “best fit” method was found to be practical and fit for purpose. Conclusions The method is suited to producing context-specific conceptual models for describing or explaining the decision-making and health behaviours of patients and other groups. It offers a pragmatic means of conducting rapid qualitative evidence synthesis and generating programme theories relating to intervention effectiveness, which might be of relevance both to researchers and policy-makers

Age-dependent effects of low-dose nicotine treatment on cocaine-induced behavioral plasticity in rats

Epidemiological evidence of early adolescent tobacco use, prior to that of marijuana and other illicit drugs, has led to the hypothesis that nicotine is a “gateway” drug that sensitizes reward pathways to the addictive effects of other psychostimulants. To test this hypothesis, we have compared the effect of a brief, low-dose nicotine pretreatment of adolescent and adult rats on subsequent locomotor response to acute and chronic cocaine. Adolescents, aged postnatal day (P) 28, and adults, aged P86, were given four daily injections of saline or nicotine (0.06 mg/kg, i.v.). At P32 and P90, rats were given acute injections of cocaine (0, 0.4 or 1.0 mg/kg, i.v.) and monitored for locomotor activity in either a habituated or novel test environment. To examine cocaine sensitization, rats were treated for 3 days with saline or cocaine (0.4 mg/kg, i.v.), and, after 1 day of withdrawal, were given a challenge dose of cocaine (0.4 mg/kg, i.v.). Nicotine pretreatment did not affect acute, drug-induced locomotor activity at either age. However, age differences in cocaine response were observed, with adolescent animals showing enhanced locomotor activity in the novel environment. Adolescent controls did not exhibit cocaine-induced locomotor sensitization, whereas adults did. Nicotine pretreatment during adolescence promoted the development and expression of a sensitized response to repeated cocaine exposure similar to that observed in saline-pretreated adult controls. These findings show that brief pretreatment with nicotine, in a low dose comparable to that inhaled in 2–4 cigarettes, enhances cocaine-induced behavioral plasticity in adolescent rats

The Great American Crime Decline : Possible Explanations

This chapter examines the most important features of the crime decline in the United States during the 1990s-2010s but also takes a broader look at the violence declines of the last three centuries. The author argues that violent and property crime trends might have diverged in the 1990s, with property crimes increasingly happening in the online sphere and thus traditional property crime statistics not being reflective of the full picture. An important distinction is made between ‘contact crimes’ and crimes that do not require a victim and offender to be present in the same physical space. Contrary to the uncertainties engendered by property crime, the declines in violent (‘contact’) crime are rather general, and have been happening not only across all demographic and geographic categories within the United States but also throughout the developed world. An analysis of research literature on crime trends has identified twenty-four different explanations for the crime drop. Each one of them is briefly outlined and examined in terms of conceptual clarity and empirical support. Nine crime decline explanations are highlighted as the most promising ones. The majority of these promising explanations, being relative newcomers in the crime trends literature, have not been subjected to sufficient empirical scrutiny yet, and thus require further research. One potentially fruitful avenue for future studies is to examine the association of the most promising crime decline explanations with improvements in self-control