Isotopes illustrate vertical transport of anthropogenic Pb by reversible scavenging within Pacific Ocean particle veils.

Reversible scavenging, the oceanographic process by which dissolved metals exchange onto and off sinking particles and are thereby transported to deeper depths, has been well established for the metal thorium for decades. Reversible scavenging both deepens the elemental distribution of adsorptive elements and shortens their oceanic residence times in the ocean compared to nonadsorptive metals, and scavenging ultimately removes elements from the ocean via sedimentation. Thus, it is important to understand which metals undergo reversible scavenging and under what conditions. Recently, reversible scavenging has been invoked in global biogeochemical models of a range of metals including lead, iron, copper, and zinc to fit modeled data to observations of oceanic dissolved metal distributions. Nonetheless, the effects of reversible scavenging remain difficult to visualize in ocean sections of dissolved metals and to distinguish from other processes such as biological regeneration. Here, we show that particle-rich "veils" descending from high-productivity zones in the equatorial and North Pacific provide idealized illustrations of reversible scavenging of dissolved lead (Pb). A meridional section of dissolved Pb isotope ratios across the central Pacific shows that where particle concentrations are sufficiently high, such as within particle veils, vertical transport of anthropogenic surface-dissolved Pb isotope ratios toward the deep ocean is manifested as columnar isotope anomalies. Modeling of this effect shows that reversible scavenging within particle-rich waters allows anthropogenic Pb isotope ratios from the surface to penetrate ancient deep waters on timescales sufficiently rapid to overcome horizontal mixing of deep water Pb isotope ratios along abyssal isopycnals.

Responsive parental support buffers the link between chronic stress and cardiometabolic risk among adolescents.

Youth exposed to chronic stress exhibit increased cardiometabolic risk which parental social support may attenuate. Notably, theories emphasize that support should be delivered responsively for it to exert buffering effects, but this has not been thoroughly tested empirically. This study examined whether timing of support is an important but unrecognized element of responsiveness during adolescence in buffering the link between chronic stress and cardiometabolic risk. Participants were 242 adolescents aged 15 years (63 % female, 38 % Black). Adolescents completed assessments of chronic stress (Life Stress Interview), and trained personnel collected anthropometric measures and blood samples to assess cardiometabolic risk (reflected in low-grade inflammation and metabolic syndrome). Adolescents also completed an eight-day diary assessment to report daily stressor exposure and parental support. Using the diary data, responsiveness of parental support was operationalized as the within-individual difference in parental support received on stressor (vs. non-stressor) days, such that increased parental support on stressor days reflected more timely support. Results suggest that responsive parental support buffered the link between chronic stress and cardiovascular risk. Specifically, chronic stress was associated with greater risk only when parental support was not temporally aligned with stress exposure, but this association was not observed among adolescents who received timely parental support. These findings shed light on why parental support may not always exert buffering effects during adolescence, highlighting the importance of taking a developmental approach to understanding protective effects.

The balance of giving versus receiving social support and all-cause mortality in a US national sample.

While numerous studies exist on the benefits of social support (both receiving and giving), little research exists on how the balance between the support that individuals regularly give versus that which they receive from others relates to physical health. In a US national sample of 6,325 adults from the National Survey of Midlife Development in the United States, participants were assessed at baseline on hours of social support given and received on a monthly basis, with all-cause mortality data collected from the National Death Index over a 23-y follow-up period. Participants who were relatively balanced in the support they gave compared to what they received had a lower risk of all-cause mortality than those who either disproportionately received support from others (e.g., received more hours of support than they gave each month) or disproportionately gave support to others (e.g., gave many more hours of support a month than they received). These findings applied to instrumental social support (e.g., help with transportation, childcare). Additionally, participants who gave a moderate amount of instrumental social support had a lower risk of all-cause mortality than those who either gave very little support or those who gave a lot of support to others. Associations were evident over and above demographic, medical, mental health, and health behavior covariates. Although results are correlational, one interpretation is that promoting a balance, in terms of the support that individuals regularly give relative to what they receive in their social relationships, may not only help to strengthen the social fabric of society but may also have potential physical health benefits.

Harshness and unpredictability: Childhood environmental links with immune and asthma outcomes.

The environment has pervasive impacts on human development, and two key environmental conditions - harshness and unpredictability - are proposed to be instrumental in tuning development. This study examined (1) how harsh and unpredictable environments related to immune and clinical outcomes in the context of childhood asthma, and (2) whether there were independent associations of harshness and unpredictability with these outcomes. Participants were 290 youth physician-diagnosed with asthma. Harshness was assessed with youth-reported exposure to violence and neighborhood-level murder rate. Unpredictability was assessed with parent reports of family structural changes. Youth also completed measures of asthma control as well as asthma quality of life and provided blood samples to assess immune profiles, including in vitro cytokine responses to challenge and sensitivity to inhibitory signals from glucocorticoids. Results indicated that harshness was associated with more pronounced pro-inflammatory cytokine production following challenge and less sensitivity to the inhibitory properties of glucocorticoids. Furthermore, youth exposed to harsher environments reported less asthma control and poorer quality of life. All associations with harshness persisted when controlling for unpredictability. No associations between unpredictability and outcomes were found. These findings suggest that relative to unpredictability, harshness may be a more consistent correlate of asthma-relevant immune and clinical outcomes.

Shallow particulate organic carbon regeneration in the South Pacific Ocean.

Particulate organic carbon (POC) produced in the surface ocean sinks through the water column and is respired at depth, acting as a primary vector sequestering carbon in the abyssal ocean. Atmospheric carbon dioxide levels are sensitive to the length (depth) scale over which respiration converts POC back to inorganic carbon, because shallower waters exchange with the atmosphere more rapidly than deeper ones. However, estimates of this carbon regeneration length scale and its spatiotemporal variability are limited, hindering the ability to characterize its sensitivity to environmental conditions. Here, we present a zonal section of POC fluxes at high vertical and spatial resolution from the GEOTRACES GP16 transect in the eastern tropical South Pacific, based on normalization to the radiogenic thorium isotope 230Th. We find shallower carbon regeneration length scales than previous estimates for the oligotrophic South Pacific gyre, indicating less efficient carbon transfer to the deep ocean. Carbon regeneration is strongly inhibited within suboxic waters near the Peru coast. Canonical Martin curve power laws inadequately capture POC flux profiles at suboxic stations. We instead fit these profiles using an exponential function with flux preserved at depth, finding shallow regeneration but high POC sequestration below 1,000 m. Both regeneration length scales and POC flux at depth closely track the depths at which oxygen concentrations approach zero. Our findings imply that climate warming will result in reduced ocean carbon storage due to expanding oligotrophic gyres, but opposing effects on ocean carbon storage from expanding suboxic waters will require modeling and future work to disentangle.

RISK PREDICTORS OF EARLY CHILDHOOD CARIES INCREMENT-A SYSTEMATIC REVIEW AND META-ANALYSIS.

This systematic review aimed to investigate the risk predictors of caries in primary teeth and evaluate their association with the increment of Early Childhood Caries (ECC) among preschool children. This systematic review included only cohort or case-control studies of at least 2 years duration, over 300 participants and with English full-text. Potentially eligible studies were retrieved from 4 electronic databases (Ovid Embase, Ovid MEDLINE; PubMed, Web of Science) from inception to March 1, 2021. Independent screening and data extraction by 2 reviewers to identify factors associated with ECC increment, including family and socioeconomic factors, dietary and oral health-related habits, and clinical parameters. A total of 18 studies from 163 potential reports were included, involving 1,159,226 preschool children. Lower parental education attainment was found associated with ECC increment (WMD:0.87; 95% CI 0.52, 1.21); whereas immigration status (WMD:-0.38; 95% CI -1.09, 0.34), gender (WMD:-0.02; 95% CI -0.28, 0.24), and dental service utilization (WMD:0.35; 95% CI -0.10, 0.79) were not significant factors for ECC increment. All included studies consistently suggested positive correlations between ECC increment and baseline caries experience, plaque level, cariogenic microorganisms, and prenatal and passive smoking, while mixed findings were detected between ECC increment with dietary and oral hygiene practices. Preschool children whose parents have low education level are more likely to have greater increment of ECC over 2 years. Existing caries lesions, increased dental plaque level, cariogenic microorganisms, prenatal or passive smoking were also consistently identified as risk factors for ECC in all reviewed studies. This systematic review highlights specific risk factors to target for the prevention of ECC and supports implementing more oral health promotion for preschool children with parents of lower educational attainment.

Glass Ionomer Sealant versus Fluoride Varnish Application to Prevent Occlusal Caries in Primary Second Molars among Preschool Children: A Randomized Controlled Trial.

Fissure sealant is a recommended preventive measure on permanent molars, but its efficacy on primary molars in preschool children is still in doubt. Sodium fluoride varnish (NaFV) enhances remineralization and is effective in preventing caries in smooth surfaces, but limited information is available regarding its use on occlusal surfaces of primary molars. The present study aimed to compare the efficacy of glass ionomer sealant (GIS) versus topical application of 5% NaFV in preventing and arresting occlusal caries in primary second molars among preschool children. One calibrated examiner examined children aged 3-4 years for visible plaque index (VPI), decayed-missing-filled primary surface (dmfs) index, and extent of carious lesions by the International Caries Detection and Assessment System (ICDAS). Subjects with 1 or more primary second molars that were sound or with incipient lesions (ICDAS 0-1), with distinct visual enamel changes (ICDAS 2), or with localized enamel breakdown (ICDAS 3) were recruited. The children were randomly assigned to either NaFV group - application of 5% NaFV at 3-monthly intervals or GIS group - 1 single placement of GIS. A parental questionnaire was used to collect information on the children's sociodemographic background and oral health-related habits. Two blinded examiners conducted clinical examinations after 6 and 12 months to evaluate the development of occlusal caries and the retention of GIS. Negative binomial regression using generalized estimating equations was employed to adjust for the clustering effect and evaluate the influence of selected variables on the development of occlusal caries into dentin at 12 months. A total of 323 children with 1,159 primary second molars received the respective preventive measures at baseline. At 12 months, 280 children with 989 molars were evaluated. Caries had developed or progressed into dentin in 7.8% and 8.0% of the molars in the NaFV and GIS groups, respectively, with no significant difference between the groups (p = 0.913). The overall retention rates of GIS were 24.6% and 13.5% at 6 and 12 months, respectively. Regression analyses showed only baseline caries experience, and an ICDAS code had a significant association with occlusal caries progression. Quarterly NaFV application and single GIS placement showed similar effectiveness in the prevention of occlusal caries development among preschool children.

High flow nasal oxygen during procedural sedation for cardiac implantable electronic device procedures: A randomised controlled trial.

BACKGROUND: High flow nasal oxygen may better support the vulnerable respiratory state of patients during procedural sedation. OBJECTIVE: The objective of this study was to investigate the effects of high flow nasal oxygen in comparison to facemask oxygen on ventilation during cardiac implantable electronic device procedures performed with procedural sedation. DESIGN: A randomised controlled trial. SETTING: The study was conducted at one academic hospital in Canada. PARTICIPANTS: Adults undergoing elective cardiac implantable electronic device procedures with sedation administered by an anaesthesia assistant, supervised by an anaesthesiologist from August 2019 to March 2020. INTERVENTIONS: Participants were randomised 1 : 1 to facemask (≥ 8 l ·â€Šmin-1) or high flow nasal oxygen (50 l ·â€Šmin-1 and a 50 : 50 oxygen to air ratio). MAIN OUTCOME MEASURES: The primary outcome was peak transcutaneous carbon dioxide. Outcomes were analysed using Bayesian statistics. RESULTS: The 129 participants who were randomised and received sedation were included. The difference in peak transcutaneous carbon dioxide was 0.0 kPa (95% CI -0.17 to 0.18). Minor adverse sedation events were 6.4 times more likely to occur in the high flow nasal oxygen group. This estimate is imprecise (95% CI 1.34 to 42.99). The odds ratio for oxygen desaturation for the high flow nasal oxygen group compared with the facemask group was 1.2 (95% CI 0.37 to 3.75). The difference in satisfaction with sedation scores between groups was 0.0 (95% CI -0.33 to 0.23). CONCLUSIONS: Ventilation, as measured by TcCO2, is highly unlikely to differ by a clinically important amount between high flow nasal oxygen at 50 l min-1 or facemask oxygen at 8 l min-1. Further research with a larger sample size would be required to determine the optimal oxygen:air ratio when using high flow nasal oxygen during cardiac implantable electronic device procedures performed with sedation. TRIAL REGISTRATION NUMBER: NCT03858257.

Evaluation of visual pedagogy in improving plaque control and gingival inflammation among preschool children with autism spectrum disorder: An interventional study.

BACKGROUND: Visual pedagogy (VP) is a behavioural intervention used to facilitate learning among autistic children. Limited studies have evaluated VP when applied to dentistry. AIM: To evaluate the effectiveness of VP in improving oral hygiene and gingival health status of autistic children. DESIGN: The interventional study was conducted among 122 autistic preschool children and their parents in Hong Kong. Toothbrushing visual pedagogy (TBVP) was provided to parents for supervising their children with toothbrushing at home. The children's sociodemographic background, developmental profile, and clinical parameters were obtained via parental questionnaire, standardised assessment form, and clinical examination, respectively. The change in plaque and gingival indices over time and potential confounding factors were evaluated with Friedman's two-way analysis of variance and logistic regressions, respectively. RESULTS: Significantly lower level of plaque and gingival inflammation was found at 3 months and 6 months than baseline. The oral health status of children with poorer baseline oral hygiene status and gingival health was more likely to improve with TBVP. Other developmental and socio-economic backgrounds had insignificant associations on the improvement of these clinical parameters. CONCLUSION: The findings suggest TBVP is effective in promoting oral hygiene maintenance and improving the periodontal conditions among individuals diagnosed with ASD.

FISSURE SEALANT IN A NUTSHELL. EVIDENCE-BASED META-EVALUATION OF SEALANTS' EFFECTIVENESS IN CARIES PREVENTION AND ARREST.

OBJECTIVE: This meta-evaluation aimed to summarize all available evidence regarding different fissure sealants on occlusal caries prevention, arrest, retention rate, adverse effect, and cost-effectiveness; when compared with no intervention, other preventive or minimally-invasive procedures. MATERIALS AND METHODS: The systematic reviews and meta-analyses were identified via four electronic databases and manual searching. Two independent reviewers performed study selection, data extraction, quality assessment with AMSTAR-2. RESULTS: Among the 366 records yielded, 38 systematic reviews were identified as eligible 24 of them included meta-analyses. Moderate evidence has supported the efficacies of resin-based sealants (RBS) in occlusal caries prevention, arrest and cost-effectiveness compared to no interventions. Low to very low certainty of evidence suggested similar effectiveness of glass-ionomer cements in caries prevention with RBS and more superior performance of resin infiltration in arresting non-cavitated occlusal lesions. CONCLUSION: This meta-evaluation supports the use of RBS on permanent molars to reduce occlusal caries occurrence, arrest lesion progression and alleviate oral health inequalities between individuals of different socioeconomic status. This meta-evaluation also advocates further research on glass-ionomer cements and resin infiltration with respect to their efficacies in caries prevention and arrest.

Commentary: Ecology momentary assessment as a tool for understanding dynamic patterns in child and adolescent health and development - reflections on Russell and Gajos (2020).

Ecological momentary assessment (EMA) has served as a methodological tool across subdisciplines in psychology, shedding light on family, personality, and affective processes, and physical and mental health. In their review, Russell and Gajos demonstrate how EMA can overcome several limitations of traditional methods in developmental psychopathology to answer questions about mental and behavioral health in youth. They also provide thoughtful future directions on integrating sensor technology, advancing modeling techniques for temporally dense data, and employing EMA for delivering interventions. This commentary similarly advocates for the use of EMA but extends Russell and Gajos's review by emphasizing EMA's utility for understanding and revealing dynamic changes and processes along micro timescales that have relevance for youth's health and development. We discuss how EMA can be especially fruitful for advancing theory and practice when administered in bursts and when combined with traditional assessments and longer-term longitudinal designs. Because such studies are resource-intensive, we also consider how extant EMA studies can be leveraged and subjected to meta- and mega-analytic techniques to inform theories and future EMA designs. We conclude that EMA is a promising tool for elucidating dynamic fluctuations in experiences and intra- and interpersonal processes that contribute to child and adolescent development and risk.

A global ocean inventory of anthropogenic mercury based on water column measurements.

Mercury is a toxic, bioaccumulating trace metal whose emissions to the environment have increased significantly as a result of anthropogenic activities such as mining and fossil fuel combustion. Several recent models have estimated that these emissions have increased the oceanic mercury inventory by 36-1,313 million moles since the 1500s. Such predictions have remained largely untested owing to a lack of appropriate historical data and natural archives. Here we report oceanographic measurements of total dissolved mercury and related parameters from several recent expeditions to the Atlantic, Pacific, Southern and Arctic oceans. We find that deep North Atlantic waters and most intermediate waters are anomalously enriched in mercury relative to the deep waters of the South Atlantic, Southern and Pacific oceans, probably as a result of the incorporation of anthropogenic mercury. We estimate the total amount of anthropogenic mercury present in the global ocean to be 290 ± 80 million moles, with almost two-thirds residing in water shallower than a thousand metres. Our findings suggest that anthropogenic perturbations to the global mercury cycle have led to an approximately 150 per cent increase in the amount of mercury in thermocline waters and have tripled the mercury content of surface waters compared to pre-anthropogenic conditions. This information may aid our understanding of the processes and the depths at which inorganic mercury species are converted into toxic methyl mercury and subsequently bioaccumulated in marine food webs.

Effectiveness of Pit and Fissure Sealants for Preventing and Arresting Occlusal Caries in Primary Molars: A Systematic Review and Meta-Analysis.

OBJECTIVE: The use of pit and fissure sealants have been well supported in permanent teeth, but no concrete evidence is available to support this procedure in primary molars. This review aims to systematically assess randomized controlled trials and summarize the evidence on the effectiveness of different sealants in prevention and arrest of the pit and fissure occlusal caries in primary molars of children. MATERIALS AND METHODS: Four electronic databases were searched from inception to March 2018. Seven studies were included in the qualitative and quantitative syntheses. Two reviewers independently selected studies, extracted data, assessed risk of bias using the revised Cochrane risk of bias tool, and evaluated the certainty in the evidence adopting the Grading of Recommendations Assessment Development and Evaluation approach. Odds ratio and retention rate of different sealants were recalculated and analyzed. RESULTS: This review identified no significant difference in the overall caries incidence and progression when evaluated over 24 months between (1) resin-based sealant (RBS) and glass ionomer sealants (GIS) or resin-modified GIS; (2) conventional and newly developed RBS; (3) autopolymerized and light-polymerized RBS; (4) RBS with topical fluoride application and topical fluoride alone; and (5) RBS with topical fluoride application and resin infiltration with topical fluoride application. The pooled estimates of the mean retention rates of RBS and GIS on primary molars over an 18-months period were 85.94% and 23.18%, respectively. The certainty in the evidence of each outcome was determined as low or very low mainly because of high risk of overall bias and imprecision. CONCLUSION: There are currently insufficient well-controlled randomized controlled clinical trials to determine whether sealants are beneficial in preventing or arresting noncavitated occlusal caries in the primary molars.

The costs of high self-control in Black and Latino youth with asthma: Divergence of mental health and inflammatory profiles.

Emerging evidence in psychology suggests a paradox whereby high levels of self-control when striving for academic success among minority youth can have physical health costs. This study tested the skin-deep resilience hypothesis in asthma- whether minority youth who are striving hard to succeed academically experience good psychological outcomes but poor asthma outcomes. Youth physician-diagnosed with asthma (N = 276, M age = 12.99; 155 = White, 121 = Black/Latino) completed interviews about school stress and a self-control questionnaire. Outcomes included mental health (anxiety/depression) and ex-vivo immunologic processes relevant to asthma (lymphocyte Th-1 and Th-2 cytokine production, and sensitivity to glucocorticoid inhibition). Physician contacts were tracked over a one-year follow-up. For minority youth experiencing high levels of school stress, greater self-control was associated with fewer mental health symptoms (beta = -0.20, p < .05), but worse asthma inflammatory profiles (larger Th-1 and Th-2 cytokine responses, lower sensitivity to glucocorticoid inhibition), and more frequent physician contacts during the one-year follow-up (beta's ranging from 0.22 to 0.43, p's < .05). These patterns were not evident in White youth. In minority youth struggling with school, high levels of self-control are detrimental to asthma inflammatory profiles and clinical outcomes. This suggests the need for health monitoring to be incorporated into academic programs to ensure that 'overcoming the odds' does not lead to heightened health risks in minority youth.

Aspects of the parent-child relationship and parent metabolic outcomes.

Much is known about the effect of parent-child relationships on child health; less is known about how parent-child relationships influence parent health. To assess the association between aspects of the parent-child relationship and parent metabolic outcomes, and whether these associations are moderated by parent gender. Five metabolic outcomes (systolic and diastolic blood pressure, heart rate, total cholesterol and glycated hemoglobin) were assessed among 261 parents (45.83 ± 5.50 years) of an adolescent child (14.57 ± 1.072 years). Parents completed questionnaires assessing their child's hassles and the quality of their days with their child. Parents' perceptions of their child's hassles were associated with parent heart rate (B = 2.954, SE = 1.267, p = 0.021) and cholesterol (B = 0.028, SE = 0.011, p = 0.010), such that greater perceived child hassles were associated with higher heart rate and cholesterol levels, on average. These associations were not moderated by parent gender (all ps > 0.30). Parent report of their day with their child was not associated with parent metabolic outcomes (all ps > 0.20). Parent gender moderated the association between parent report of their day with their child and parent systolic blood pressure (B = 13.861, SE = 6.200, p = 0.026), such that less positive reports were associated with higher blood pressure readings among fathers, but not mothers. This study suggests that parent metabolic health may in part be influenced by aspects of the parent-child relationship.

Chronic Family Stress and Adolescent Health: The Moderating Role of Emotion Regulation.

OBJECTIVE: The aim of the study was to assess whether the association between chronic family stress and physiological measures is moderated by emotion regulation strategies in an adolescent sample. METHODS: Chronic family stress was assessed via a semistructured interview and emotion regulation strategies (cognitive reappraisal and suppression) via questionnaire among 261 adolescents (14.57 (1.07) years). Several metabolic (waist-hip ratio, systolic and diastolic blood pressure) and inflammatory markers (basal and stimulated proinflammatory cytokine production in response to bacterial challenge) as well as glucocorticoid sensitivity were assessed. RESULTS: There were no main effects of chronic family stress, cognitive reappraisal, or suppression on physiological measures (all p's > .10). Emotion regulation moderated the association between chronic family stress and physiological measures. As chronic family stress increased, adolescents higher in cognitive reappraisal had smaller waist-hip ratios (B = -.003, SE = .001, p = .015) and lower systolic blood pressure (B = -.303, SE = .143, p = .035), although no moderation was found with respect to inflammatory markers and glucocorticoid sensitivity (all p's > .30). In addition, as chronic family stress increased, adolescents higher in suppression showed evidence of higher stimulated proinflammatory cytokine production (B = .046, SE = .020, p = .021) and lower glucocorticoid sensitivity (B = .051, SE = .021, p = .015), although basal inflammation and metabolic measures were not moderated by suppression (all p's > .50). CONCLUSIONS: This study suggests that the types of emotion regulation strategies used by adolescents may affect the extent to which chronic family stress affects important metabolic and immune processes.

One size does not fit all: Links between shift-and-persist and asthma in youth are moderated by perceived social status and experience of unfair treatment.

The links between low socioeconomic status and poor health are well established, yet despite adversity, some individuals with low socioeconomic status appear to avoid these negative consequences through adaptive coping. Previous research found a set of strategies, called shift-and-persist (shifting the self to stressors while persisting by finding meaning), to be particularly adaptive for individuals with low socioeconomic status, who typically face more uncontrollable stressors. This study tested (a) whether perceived social status, similar to objective socioeconomic status, would moderate the link between shift-and-persist and health, and (b) whether a specific uncontrollable stressor, unfair treatment, would similarly moderate the health correlates of shift-and-persist. A sample of 308 youth (Meanage = 13.0, range 8-17), physician diagnosed with asthma, completed measures of shift-and-persist, unfair treatment, asthma control, and quality of life in the lab, and 2 weeks of daily diaries about their asthma symptoms. Parents reported on perceived family social status. Results indicated that shift-and-persist was associated with better asthma profiles, only among youth from families with lower (vs. higher) parent-reported perceived social status. Shift-and-persist was also associated with better asthma profiles, only among youth who experienced more (vs. less) unfair treatment. These findings suggest that the adaptive values of coping strategies for youth with asthma depend on the family's perceived social status and on the stressor experienced.

Exploring healthcare professionals' perceptions of the anesthesia assistant role and its impact on patients and interprofessional collaboration.

To practice interprofessional collaboration (IPC), understanding the roles of each profession in the team is key. Anesthesia assistants (AAs) are a relatively new addition to the Canadian healthcare system. As a result, its role in the delivery of anesthesia care can be misunderstood by other healthcare professionals. Using an exploratory multiple case study design, this article explores healthcare professionals' perceptions of the AA role and its impact on patients and IPC. Sixteen semi-structured, in-depth interviews were conducted with a purposive sample of nine healthcare professions from inside and outside the peri-operative care unit in two urban, acute care, university-affiliated teaching research hospitals in Ontario. A thematic analysis of the interview transcripts identified five overarching themes: limited understanding of the AA role, improved patient-centred care, improve IPC and interprofessional education, ongoing challenges, and the future direction for professional growth. Results indicated that despite regular clinical practice collaboration, participants have a limited understanding of AAs in terms of their educational prerequisites, scope of practice, and roles. One reason for this lack of understanding is that there is a high variability of titles and clinical duties for non-physician anesthesia providers. The diverse range of anesthesia services provided by AAs can also become a barrier to the full understanding of their scope of practice and roles. The limited understanding of the AA role was reported as one of AAs' ongoing challenges. It prevents AAs from realising their full scope of practice. Participants suggested that AAs' professional growth should focus on promoting and expanding their role. Understanding other healthcare professionals' perceptions of AAs will assist them to become better ambassadors for their role, and to more effectively promote and practice IPC. Ultimately, this will result in improved interprofessional teamwork to deliver effective and efficient patient care.

Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learned from GEOTRACES.

Continental shelves and shelf seas play a central role in the global carbon cycle. However, their importance with respect to trace element and isotope (TEI) inputs to ocean basins is less well understood. Here, we present major findings on shelf TEI biogeochemistry from the GEOTRACES programme as well as a proof of concept for a new method to estimate shelf TEI fluxes. The case studies focus on advances in our understanding of TEI cycling in the Arctic, transformations within a major river estuary (Amazon), shelf sediment micronutrient fluxes and basin-scale estimates of submarine groundwater discharge. The proposed shelf flux tracer is 228-radium (T1/2 = 5.75 yr), which is continuously supplied to the shelf from coastal aquifers, sediment porewater exchange and rivers. Model-derived shelf 228Ra fluxes are combined with TEI/ 228Ra ratios to quantify ocean TEI fluxes from the western North Atlantic margin. The results from this new approach agree well with previous estimates for shelf Co, Fe, Mn and Zn inputs and exceed published estimates of atmospheric deposition by factors of approximately 3-23. Lastly, recommendations are made for additional GEOTRACES process studies and coastal margin-focused section cruises that will help refine the model and provide better insight on the mechanisms driving shelf-derived TEI fluxes to the ocean.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.