Long term time variability of cosmic rays and possible relevance to the development of life on Earth

An analysis is made of the manner in which the cosmic ray intensity at Earth has varied over its existence and its possible relevance to both the origin and the evolution of life. Much of the analysis relates to the 'high energy' cosmic rays ($E>10^{14}eV;=0.1PeV$) and their variability due to the changing proximity of the solar system to supernova remnants which are generally believed to be responsible for most cosmic rays up to PeV energies. It is pointed out that, on a statistical basis, there will have been considerable variations in the likely 100 My between the Earth's biosphere reaching reasonable stability and the onset of very elementary life. Interestingly, there is the increasingly strong possibility that PeV cosmic rays are responsible for the initiation of terrestrial lightning strokes and the possibility arises of considerable increases in the frequency of lightnings and thereby the formation of some of the complex molecules which are the 'building blocks of life'. Attention is also given to the well known generation of the oxides of nitrogen by lightning strokes which are poisonous to animal life but helpful to plant growth; here, too, the violent swings of cosmic ray intensities may have had relevance to evolutionary changes. A particular variant of the cosmic ray acceleration model, put forward by us, predicts an increase in lightning rate in the past and this has been sought in Korean historical records. Finally, the time dependence of the overall cosmic ray intensity, which manifests itself mainly at sub-10 GeV energies, has been examined. The relevance of cosmic rays to the 'global electrical circuit' points to the importance of this concept.Comment: 18 pages, 5 figures, accepted by 'Surveys in Geophysics

The Faith, Activity, and Nutrition program: a randomized controlled trial in African-American churches

Background: Faith-based interventions hold promise for promoting health in ethnic minority populations. To date, however, few of these interventions have used a community-based participatory research (CBPR) approach, have targeted both physical activity and healthy eating, and have focused on structural changes in the church. Setting/participants: Seventy-four African Methodist Episcopal (AME) churches in South Carolina and 1257 members within them participated in the study. Intervention: Churches were randomized to an immediate (intervention) or delayed (control) 15-month intervention that targeted organizational and environmental changes consistent with the structural ecologic model. A CBPR approach guided intervention development. Intervention churches attended a full-day committee training and a full-day cook training. They also received a stipend and 15 months of mailings and technical assistance calls to support intervention implementation. Main outcome measures: Primary outcomes were self-reported moderate-to vigorous-intensity physical activity (MVPA), self-reported fruit and vegetable consumption, and measured blood pressure. Secondary outcomes were self-reported fat-and fıber-related behaviors. Measurements were taken at baseline and 15 months. Intent-to-treat repeated measures ANOVA tested group X time interactions, controlling for church clustering, wave, and size, and participant age, gender, and education. Post hoc ANCOVAs were conducted with measurement completers. Results: There was a signifıcant effect favoring the intervention group in self-reported leisure-time MVPA (dϭ0.18, pϭ0.02), but no effect for other outcomes. ANCOVA analyses showed an intervention effect for self-reported leisure-time MVPA (dϭ0.17, pϭ0.03). Trainings were evaluated very positively (training evaluation item means of 4.2-4.8 on a 5-point scale). Conclusions: This faith-based structural intervention using a CBPR framework showed small but signifıcant increases in self-reported leisure-time MVPA. This program has potential for broadbased dissemination and reach. Trial registration: This study is registered at www.clinicaltrials.gov NCT00379925. (Am J Prev Med 2013;44(2):122-131