Additive Pressures of Elevated Sea Surface Temperatures and Herbicides on Symbiont-Bearing Foraminifera

Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F′m), while elevated temperatures (>30°C, only 2°C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (Fv/Fm), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced Fv/Fm and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥1 µg L−1). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures

Rheumatoid arthritis, cardiovascular disease and physical exercise: a systematic review

This systematic review investigates the effectiveness of exercise interventions in improving disease-related characteristics in patients with rheumatoid arthritis (RA). It also provides suggestions for exercise programmes suitable for improving the cardiovascular profile of RA patients and proposes areas for future research in the field. Six databases (Medline, Cochrane Library, CINAHL, Google Scholar, EMBASE and PEDro) were searched to identify publications from 1974 to December 2006 regarding RA and exercise interventions. The quality of the studies included was determined by using the Jadad scale. Initial searches identified 1342 articles from which 40 met the inclusion criteria. No studies were found investigating exercise interventions in relation to cardiovascular disease in RA. There is strong evidence suggesting that exercise from low to high intensity of various modes is effective in improving disease-related characteristics and functional ability in RA patients. Future studies are required to investigate the effects of exercise in improving the cardiovascular status of this patient population