Directions of seismic anisotropy in laboratory models of mantle plumes

A recent expansion in global seismic anisotropy data provides important new insights about the style of mantle convection. Interpretations of these geophysical measurements rely on complex relationships between mineral physics, seismology, and mantle dyn

Session 3-3-C: The National Longitudinal Study of Gambling Behaviour (NLSGB): Preliminary Results

Introduction The NLSGB tracked 300 gamblers over a 15-month period. A comprehensive survey instrument was compiled to analyse factors that might influence changes in risk of gambling problems over time. The study was conducted in the four major metropolitan areas of South Africa: Johannesburg, Tshwane, Durban and Cape Town. We will discuss the study’s design and implementation and some preliminary results

Smoking and Intertemporal Risk Attitudes

Atemporal risk preferences, time preferences, and intertemporal risk preferences are central to economic explanations of addiction, but have received little attention in the experimental economic literature on substance use. We conduct an incentive-compatible experiment designed to elicit the atemporal risk preferences, time preferences, and intertemporal risk preferences of a sample of student (n = 145) and staff (n = 111) smokers, ex-smokers, and non-smokers at the University of Cape Town in 2016-2017. We estimate a structural model of intertemporal risk preferences jointly with a rank-dependent utility model of choice under atemporal risk and a quasi-hyperbolic model of time preferences. We find no substantive differences in atemporal risk preferences according to smoking status, smoking intensity, and smoking severity, but do find that time preferences have an economically significant association with smoking behaviour. Smokers discount at a far higher rate than non-smokers, and ex-smokers discount at a level between these groups. There is also a large, positive relationship between smoking intensity and discounting behaviour that has important implications for treatment. The intertemporal risk preferences of our sample exhibit significant heterogeneity and we find, contrary to the assumption employed by some economic models, that smokers do not exhibit intertemporal risk seeking behaviour. Instead, our sample is characterised by high levels of intertemporal risk aversion which varies by smoking intensity and smoking severity in men, but not in women

Delivering HIV prevention medication online: findings from a qualitative study exploring the acceptability of an online HIV pre-exposure prophylaxis (PrEP) care pathway among service users and healthcare professionals

Objective: Eliminating HIV transmission worldwide could become a reality with the advent of HIV pre-exposure prophylaxis (PrEP) where people take HIV medication to prevent HIV acquisition. Incorporating digital health into PrEP provision could help services scale up and meet increasing demand. We aimed to explore the prospective acceptability of a novel online PrEP care pathway (the ePrEP clinic) among PrEP users and healthcare professionals. The ePrEP clinic is composed of online postal self-sampling for HIV and other sexually transmitted infections, an online consultation, and remote medication provision.Methods: We conducted semi-structured interviews with 15 PrEP users recruited from a large sexual health service and online cohort, and focus groups with nine healthcare professionals from the same sexual health service (May to December 2021). We analysed data using framework analysis.Results: Participants found the ePrEP clinic highly acceptable, anticipating that it would provide convenience, empower PrEP users, and increase capacity within sexual health services. The need for blood self-sampling was a considerable barrier for some. Participants anticipated that the ePrEP clinic would be appropriate for established PrEP users with adequate digital health literacy and no medically significant conditions requiring in-clinic monitoring. Participants highlighted the need for support, including access to in-clinic care, and the integration of the ePrEP clinic within existing services.Conclusions: Our findings provide clear justification for the development of the ePrEP clinic as an addition to in-clinic PrEP care pathways and provide useful insights for those developing digital services for other conditions incorporating testing, consultations, and prescribing

Understanding and responding to remote mental health help-seeking by gay, bisexual and other men who have sex with men (GBMSM) in the U.K. and Republic of Ireland : a mixed-method study conducted in the context of COVID-19

Background: Gay, bisexual and other men who have sex with men (GBMSM) are at far greater risk of experiencing poor mental health (MH) than wider society. This disparity was exacerbated by additional unique to sexual minority status' COVID-19 stressors. Objective: This sequential, mixed-methods study examined remote MH help-seeking among GBMSM in the U.K. and Ireland during the first COVID-19 lockdown. Methods and Results: Quantitative survey data (n = 1368), analysed with logistic regression, suggested GBMSM experiencing moderate-to-severe anxiety and those with a past MH diagnosis were most likely to seek MH support. Thematic analysis of qualitative interview (n = 18) data identified multiple barriers and enablers to GBMSM seeking remote MH help, with the help primarily sought from GBMSM-facing organisations and generic online resources. Finally, the behaviour change wheel was used to generate theoretically informed recommendations to promote MH help-seeking among GBMSM in Scotland. Implications: We discuss how applying these recommendations in the short, medium and long term will begin to address GBMSM's MH needs, post COVID-19

The importance of socio-economic context for social marketing models for improving reproductive health: Evidence from 555 years of program experience

BACKGROUND: Over the past two decades, social marketing programs have become an important element of the national family planning and HIV prevention strategy in several developing countries. As yet, there has not been any comprehensive empirical assessment to determine which of several social marketing models is most effective for a given socio-economic context. Such an assessment is urgently needed to inform the design of future social marketing programs, and to avoid that programs are designed using an ineffective model. METHODS: This study addresses this issue using a database of annual statistics about reproductive health oriented social marketing programs in over 70 countries. In total, the database covers 555 years of program experience with social marketing programs that distribute and promote the use of oral contraceptives and condoms. Specifically, our analysis assesses to what extent the model used by different reproductive health social marketing programs has varied across different socio-economic contexts. We then use random effects regression to test in which socio-economic context each of the models is most successful at increasing use of socially marketed oral contraceptives and condoms. RESULTS: The results show that there has been a tendency to design reproductive health social marketing program with a management structure that matches the local context. However, the evidence also shows that this has not always been the case. While socio-economic context clearly influences the effectiveness of some of the social marketing models, program maturity and the size of the target population appear equally important. CONCLUSIONS: To maximize the effectiveness of future social marketing programs, it is essential that more effort is devoted to ensuring that such programs are designed using the model or approach that is most suitable for the local context

Autocracy-Sustaining Versus Democratic Federalism:Explaining the Divergent Trajectories of Territorial Politics in Russia and Western Europe

This article provides a comparative assessment of territorial politics in Russia and Western Europe. The consolidation or deepening of regional autonomy in Western Europe contrasts with the transformation of Russia from a segmented and highly centrifugal state into a centralized authoritarian state in the course of just two decades. The consolidation of territorial politics in Western Europe is linked to the presence of endogenous safeguards that are built into their territorial constitutional designs and most importantly to the dynamics that emanate from multi-level party competition in the context of a liberal and multi-level democracy. In contrast, in Russia, neither endogenous safeguards nor multi-level party democracy play an important role in explaining the dynamics of Russian federalism, but who controls key state resources instead. We argue that under Putin power dependencies between the Russian center and the regions are strongest where regional democracy is at its weakest, thus producing ‘autocracy-sustaining’ instead of a democratic federation. By studying the relationship between federalism and democracy in cases where both concepts are mutually reinforcing (as in Western Europe) with the critical case of Russia where they are not, we question the widely held view that democracy is a necessary pre-condition for federalism.Peer reviewe

Grain-size distribution in the mantle wedge of subduction zones

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): B10203, doi:10.1029/2011JB008294.Mineral grain size plays an important role in controlling many processes in the mantle wedge of subduction zones, including mantle flow and fluid migration. To investigate the grain-size distribution in the mantle wedge, we coupled a two-dimensional (2-D) steady state finite element thermal and mantle-flow model with a laboratory-derived grain-size evolution model. In our coupled model, the mantle wedge has a composite olivine rheology that incorporates grain-size-dependent diffusion creep and grain-size-independent dislocation creep. Our results show that all subduction settings lead to a characteristic grain-size distribution, in which grain size increases from 10 to 100 μm at the most trenchward part of the creeping region to a few centimeters in the subarc mantle. Despite the large variation in grain size, its effect on the mantle rheology and flow is very small, as >90% of the deformation in the flowing part of the creeping region is accommodated by grain-size-independent dislocation creep. The predicted grain-size distribution leads to a downdip increase in permeability by ∼5 orders of magnitude. This increase is likely to promote greater upward migration of aqueous fluids and melts where the slab reaches ∼100 km depth compared with shallower depths, potentially providing an explanation for the relatively uniform subarc slab depth. Seismic attenuation derived from the predicted grain-size distribution and thermal field is consistent with the observed seismic structure in the mantle wedge at many subduction zones, without requiring a significant contribution by the presence of melt.Funding for this research was provided by the National Science Foundation through a MARGINS Postdoctoral Fellowship (NSF OCE‐0840800) and NSF grant EAR‐0854673