Nonautonomous saddle-node bifurcations: random and deterministic forcing

We study the effect of external forcing on the saddle-node bifurcation pattern of interval maps. By replacing fixed points of unperturbed maps by invariant graphs, we obtain direct analogues to the classical result both for random forcing by measure-preserving dynamical systems and for deterministic forcing by homeomorphisms of compact metric spaces. Additional assumptions like ergodicity or minimality of the forcing process then yield further information about the dynamics. The main difference to the unforced situation is that at the critical bifurcation parameter, two alternatives exist. In addition to the possibility of a unique neutral invariant graph, corresponding to a neutral fixed point, a pair of so-called pinched invariant graphs may occur. In quasiperiodically forced systems, these are often referred to as 'strange non-chaotic attractors'. The results on deterministic forcing can be considered as an extension of the work of Novo, Nunez, Obaya and Sanz on nonautonomous convex scalar differential equations. As a by-product, we also give a generalisation of a result by Sturman and Stark on the structure of minimal sets in forced systems.Comment: 17 pages, 5 figure

The role of a community conversation intervention in reducing stigma related to lower limb lymphoedema in Northern Ethiopia

Background: Stigma related to lower-limb lymphoedema poses a major psychosocial burden to affected persons and acts as a barrier to them accessing morbidity management and disability prevention (MMDP) services. Community Conversation (CC), which actively engages community members and disseminates health information amongst them, is believed to break the vicious cycle of stigma by enhancing disease-related health literacy at the community level. Methods: A quasi-experimental study was conducted in Northern Ethiopia to assess the role of the CC intervention in reducing stigma. In two control districts, a comprehensive and holistic MMDP care package was implemented that included physical health, mental health and psychosocial interventions, whilst in the intervention district the CC intervention was added to the MMDP care package. A total of 289 persons affected by lymphoedema and 1659 community members without lymphoedema were included in the study. Results: Over the course of the intervention, in all sites, community members’ knowledge about the causes of lymphoedema increased, and perceived social distance and stigmatizing attitudes towards people with lymphoedema decreased in the community, whilst experienced and internalized stigma decreased amongst affected persons. There were no significant changes for perceived social support. However, the changes were greater in the control sites overall, i.e. those districts in which the holistic care package was implemented without CC. Conclusion: The findings suggest that the CC intervention provides no additional stigma reduction when used alongside a holistic MMDP care package. Provision of comprehensive and holistic MMDP services may be adequate and appropriate to tackle stigma related to lower-limb lymphoedema in a resource-constrained setting like Ethiopia.</p