Population-dependent effects of ocean acidification.

Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica.The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects.

Experimental climate change weakens the insurance effect of biodiversity.

Ecosystems are simultaneously affected by biodiversity loss and climate change, but we know little about how these factors interact. We predicted that climate warming and CO (2) -enrichment should strengthen trophic cascades by reducing the relative efficiency of predation-resistant herbivores, if herbivore consumption rate trades off with predation resistance. This weakens the insurance effect of herbivore diversity. We tested this prediction using experimental ocean warming and acidification in seagrass mesocosms. Meta-analyses of published experiments first indicated that consumption rate trades off with predation resistance. The experiment then showed that three common herbivores together controlled macroalgae and facilitated seagrass dominance, regardless of climate change. When the predation-vulnerable herbivore was excluded in normal conditions, the two resistant herbivores maintained top-down control. Under warming, however, increased algal growth outstripped control by herbivores and the system became algal-dominated. Consequently, climate change can reduce the relative efficiency of resistant herbivores and weaken the insurance effect of biodiversity.

Aggregation-Induced Synthesis (AIS): Asymmetric Synthesis via Chiral Aggregates.

A new chiral aggregate-based tool for asymmetric synthesis has been developed by taking advantage of chiral aggregates of GAP (Group-Assisted Purification) reagents, N-phosphonyl imines. This tool was proven to be successful in the asymmetric GAP synthesis of functionalized 2,3-dihydrobenzofurans by reacting salicyl N-phosphonyl imines with dialkyl bromomalonates in various cosolvent systems. The chiral induction can be controlled by differentiating between two asymmetric directions simply by changing the ratios of cosolvents which are commonly adopted in AIE (aggregation-induced emission) systems. The formation of chiral aggregates was witnessed by a new analytical tool-aggregation-induced polarization (AIP). The present synthetic method will be broadly extended for general organic synthesis, particularly, for asymmetric synthesis and asymmetric catalysis in the future.

Ocean acidification may increase calcification rates, but at a cost.

Ocean acidification is the lowering of pH in the oceans as a result of increasing uptake of atmospheric carbon dioxide. Carbon dioxide is entering the oceans at a greater rate than ever before, reducing the ocean's natural buffering capacity and lowering pH. Previous work on the biological consequences of ocean acidification has suggested that calcification and metabolic processes are compromised in acidified seawater. By contrast, here we show, using the ophiuroid brittlestar Amphiura filiformis as a model calcifying organism, that some organisms can increase the rates of many of their biological processes (in this case, metabolism and the ability to calcify to compensate for increased seawater acidity). However, this upregulation of metabolism and calcification, potentially ameliorating some of the effects of increased acidity comes at a substantial cost (muscle wastage) and is therefore unlikely to be sustainable in the long term.

Peer assessment of resuscitation skills.

INTRODUCTION: Peer tuition has been identified as a useful tool for delivering undergraduate healthcare training in basic life support. The aim of this study was to test the expansion of the peer tuition model to include peer assessment of performance. The study also sought to establish the attitudes towards peer assessment among the course students and tutors. METHODS: Students undergoing an end-of-course test in basic life support were simultaneously assessed by peer and faculty assessors, and the reliability of assessment results was measured. Students' and peer assessors' attitudes to peer assessment were also measured, by questionnaire. RESULTS: In all 162 candidates were assessed by 9 sets of peers and faculty examiners. Inter-observer agreement was high (>95%) for all assessment domains apart from chest compressions (93%). Agreement on the final pass/fail decision was less consistent at 86%, because of the lower pass rate of 71% (115/162) afforded by peer assessors compared with 82% (132/162) by faculty assessors (p=0.0008). Peer assessor sensitivity and specificity were 85% was 90%, respectively, with positive predictive value of 97% and negative predictive value of 57%. CONCLUSION: Senior healthcare students can make reliable assessments of their peers' performance during an end-of-course test in basic life support. Students preferred peer assessment, and the peer assessment process was acceptable to the majority of students and peer assessors.