Stratospheric aerosol - Observations, processes, and impact on climate

Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes

Intensive group-based cognitive therapy in patients with cardiac disease and psychological distress-a randomized controlled trial protocol

Abstract Background Many patients with coronary artery disease (CAD) and valvular heart disease (VHD) suffer from psychological distress. Such stress is associated with increased morbidity, reduced quality of life and delayed return to work. European guidelines emphasize recognition and intervention, but evidence-based treatment options are limited and perceived as costly. The present study will test the effect of brief, group-based cognitive therapy as an adjunct to usual cardiac rehabilitation in a randomized design. Methods A total of 148 patients with CAD and/or VHD after surgical intervention and concomitant psychological distress (defined as HADS anxiety (A) or depression (D) score ≥8) will be randomized to either usual out-patient cardiac rehabilitation (CR) comprising an 8-week multidisciplinary programme or usual care supplemented by five group-based cognitive therapy sessions performed by trained CR nurses. A structured, standardized treatment manual will be used. Patients will be randomized 1:1 at three different sites. Additionally, a non-randomized sub-group of 40 matched patients without signs of psychological distress will be followed to investigate spontaneous variation in HADS. The primary outcome is Hospital Anxiety and Depression Score (HADS). Secondary outcomes are adherence to cardiac rehabilitation (CR), health-related quality of life measured by HeartQoL, time to return to work, adherence to lifestyle interventions and cardiovascular readmissions. Patients are followed up for 12 months. Discussion To our knowledge, this is the first randomized controlled trial (RCT) on patients with cardiac disease with an intensive group-based programme of cognitive therapy performed by CR nurses, which makes it affordable and widely implementable. The outcome will elucidate the feasibility and effect of cognitive therapy as an adjunct to CR in patients with post-surgery CAD and/or VHD and psychological distress and could possibly benefit patients with other heart conditions as well. The clinical trial complies with the Declaration of Helsinki. The trial has been approved by The Regional Research Ethics Committee (file number H-16042832) and The Danish Data Protection Agency. The results will be disseminated as original research in peer-reviewed manuscripts. Trial registration www.clinicaltrials.gov NCT04254315 . Retrospectively registered on 30 January 2020