Resilience of pore-water chemistry and calcification in photosynthetic zones of calcifying sediments

Photosynthetically driven calcification was investigated in diatom‐dominated carbonate sediments from Bait Reef, Australia. Laboratory measurements conducted over complete diel cycles, using O2, pH, CO32‐, and Ca2+ microsensors, confirmed that photosynthesis and respiration drive calcification and calcium release via their respective effects on the local pH. However, the dark situation does not simply mirror the light situation. Profiles showed that calcification and calcium release are not necessarily tightly coupled to the light cycle and that mass transfer phenomena need to be considered in diel chemical dynamics. The magnitude and timing of pH and CO2{ 3 concentration changes did not simply follow the light cycle. The pH in the upper 3 mm of the sediment changed more rapidly upon illumination than upon darkening. Consequently, photosynthetically induced calcification began shortly (within 1 h) after illumination, but the pH remained elevated and calcification continued for ~7 h after darkening. Thus, calcification in marine phototrophic sediments is not limited to light periods, but may continue for extended periods after darkening. This decoupling of light, photosynthesis, and calcification has profound consequences for estimates of daily calcification rates, which have previously been made from measurements assuming close to steady states and 12 : 12 h light : dark calcification and decalcification. In Bait Reef sediments, such an assumption underestimates daily calcification rates by two‐ to threefold

A multination study of socioeconomic inequality in expectations for progression to higher education: the role of between-school tracking and ability stratification

Persistent inequalities in educational expectations across societies are a growing concern. Recent research has explored the extent to which inequalities in education are due to primary effects (i.e., achievement differentials) versus secondary effects (i.e., choice behaviors net of achievement). We explore educational expectations in order to consider whether variations in primary and secondary effects are associated with country variation in curricular and ability stratification. We use evidence from the PISA 2003 database to test the hypothesis that (a) greater between-school academic stratification would be associated with stronger relationships between socioeconomic status and educational expectations and (b) when this effect is decomposed, achievement differentials would explain a greater proportion of this relationship in countries with greater stratification. Results supported these hypotheses

The malignant epidemic-changing patterns of trauma

Objectives and Setting. The worldwide burden of trauma is increasing, but is unequally distributed between nations. Trauma in South Africa targets the young and productive in society and imposes a major burden on the health infrastructure. We undertook a review of injury trends among patients attending the Johannesburg Hospital Trauma Unit (JHTU) and the Johannesburg Medicolegal Laboratory (JMLL) in order to document the evolution in patterns of trauma over a 17-year period of great social and political change. Design, subjects and outcome measures. This was a retrospective review of all priority-one patients attending the JHTU from January 1985 to December 2001. The JHTU trauma database was used to retrieve information on patient demographics, wound mechanism and injury severity. The database at the JMLL, maintained since 1996, was examined and the manner and place of death were analysed.Results. The JHTU has seen an unprecedented increase in the number of trauma patients over the last 17 years. The patients' demographic profiles have altered and injury is now predominantly due to interpersonal violence. Unnatural deaths examined at the JMLL have declined by 19% since 1996; however, the proportion of those deaths due to gunshot wounds has risen.Conclusions. The social and political changes in South Africa in recent years have led to changes in the injury profiles seen at the JHTU. Part of the increase can be explained by desegregation and a reduction in the provision of local hospital services; however, the impact of urbanisation within South Africa, cross-border migration and the high incidence of substance abuse are recognised. Evidence supports the implementation of legislative, environmental, social and behavioural interventions to contain and reduce the incidence and impact of violence and injury. Concerted efforts must be made at all levels to curb South Africa's  trauma  epidemic

Personal preferences of participation in fall prevention programmes: A descriptive study

Background: Participation in fall prevention programmes is associated with lower risk of injurious falls among older adults. However participation rates in fall prevention interventions are low. The limited participation in fall prevention might increase with a preference based approach. Therefore, the aims of this study are to a) determine the personal preferences of older adults regarding fall prevention and b) explore the association between personal preferences and participation. Methods: We assessed the personal preferences of older adults and the association between their preferences, chosen programme and participation level. Nine different programmes, with a focus on those best matching their personal preferences, were offered to participants. Twelve weeks after the start of the programme, participation was assessed by questionnaire. Logistic regression was performed to test the association between preferences and participation and an ANOVA was performed to assess differences between the number of preferences included in the chosen programme and participation level. Results: Of the 134 participants, 49% preferred to exercise at home versus 43% elsewhere, 46% preferred to exercise alone versus 44% in a group and 41% indicated a programme must be free of charge while 51% were willing to pay. The combination of an external location, in a group and for a fee was preferred by 27%, whereas 26% preferred at home, alone and only for free. The presence of preferences or the extent to which the programme matched earlier preferences was not associated with participation. Conclusion: Despite the fact that preferences can vary greatly among older adults, local programmes should be available for at least the two largest subgroups. This includes a programme at home, offered individually and for free. In addition, local healthcare providers should cooperate to increase the accessibility of currently available group programmes

Effects of context pre-exposure and delay until anxiety retrieval on generalization of contextual anxiety

Animal studies suggest that time delay between acquisition and retrieval of contextual anxiety increases generalization. Moreover, such generalization is prevented by preexposure to the context (CTX), presumably due to an improved representation of such context. We investigated whether preexposure and time-passing modulate generalization of contextual anxiety, in humans. On Day 1, 42 participants (preexposure group) explored two virtual offices, while 41 participants (no-preexposure group) explored a virtual stadium. On Day 2 (24 h later), all participants learned to associate one office (CTX+) with unpredictable unconditioned stimuli (USs), and another office (CTX2) with safety. On Day 3, either 24 h (recent test) or 2 wk (remote test) later, participants revisited CTX2 and CTX+ without USs, as well as a generalization context (G-CTX). Results revealed successfully conditioned anxiety and anxiety generalization for ratings (G-CTX was as aversive as CTX+ was), while safety generalization was found for startle responses (G-CTX elicited startle attenuation as CTX2 did). Time between learning and testing enhanced generalization as reflected by comparable startle responses to all three offices in the remote test. Contextual preexposure facilitated extinction of explicit conditioned anxiety assessed with ratings. These results suggest that memory trace of a context degrades with passage of time in humans like in animals and, consequently, anxiety generalization enhances. After context preexposure, high cognitive processes seem to be crucially involved in facilitating extinction (or safety) learning

Economic transition and speculative urbanisation in China: gentrification versus dispossession

Gentrification requires properties to be available for investment through market transactions. In mainland China which has gone through transition from a planned to a market economy, it is necessary to unleash decommodified real estate properties and make them amenable to investment. This entails inhabitants’ dispossession to dissociate them from claiming their rights to the properties and to their neighbourhoods. This paper argues that while China’s urban accumulation may have produced new-build gentrification, redevelopment projects have been targeting dilapidated urban spaces that are yet to be fully converted into commodities. This means that dispossession is a precursor to gentrification. Dispossession occurs through both coercion and co-optation, and reflects the pathdependency of China’s socialist legacy. The findings contribute to the debates on contextualising the workings of gentrification in the global South, and highlight the importance of identifying multiple urban processes at work to produce gentrification and speculative urban accumulation

The use of dexamethasone in women with preterm premature rupture of membranes - A multicentre, double-blind, placebocontrolled, randomised trial

No Abstract

Substantial and sustained improvement of serrated polyp detection after a simple educational intervention: Results from a prospective controlled trial

Objective: Serrated polyps (SPs) are an important cause of postcolonoscopy colorectal cancers (PCCRCs), which is likely the result of suboptimal SP detection during colonoscopy. We assessed the long-term effect of a simple educational intervention focusing on optimising SP detection. Design: An educational intervention, consisting of two 45 min training sessions (held 3 years apart) on serrated polyp detection, was given to endoscopists from 9 Dutch hospitals. Hundred randomly selected and untrained endoscopists from other hospitals were selected as control group. Our primary outcome measure was the proximal SP detection rate (PSPDR) in trained versus untrained endoscopists who participated in our faecal immunochemical test (FIT)-based population screening programme. Results: Seventeen trained and 100 untrained endoscopists were included, who performed 11 305 and 51 039 colonoscopies, respectively. At baseline, PSPDR was equal between the groups (9.3% vs 9.3%). After training, the PSPDR of trained endoscopists gradually increased to 15.6% in 2018. This was significantly higher than the PSPDR of untrained endoscopists, which remained stable around 10% (p=0.018). All below-average (ie, PSPDR ≤6%) endoscopists at baseline improved their PSPDR after training session 1, as did 57% of endoscopists with average PSPDR (6%-12%) at baseline. The second training session further improved the PSPDR in 44% of endoscopists with average PSPDR after the first training. Conclusion: A simple educational intervention was associated with substantial long-term improvement of PSPDR in a prospective controlled trial within FIT-based population screening. Widespread implementation of such interventions might be an easy way to improve SP detection, which may ultimately result in fewer PCCRCs. Trial registration number: NCT03902899