Radiocarbon dating of deep-sea corals

Deep-sea corals are a promising new archive of paleoclimate. Coupled radiocarbon and U-series dates allow ^(14)C to be used as a tracer of ocean circulation rate in the same manner as it is used in the modern ocean. Diagnetic alteration of coral skeletons on the seafloor requires a thorough cleaning of contaminating phases of carbon. In addition, 10% of the coral must be chemically leached prior to dissolution to remove adsorbed modern CO_2. A survey of modern samples from the full Δ^(14)C gradient in the deep ocean demonstrates that the coralline CaCO_3 records the radiocarbon value of the dissolved inorganic carbon

PII S0016-7037(99)00422-6 U-Th dating of deep-sea corals

Abstract Th not due to closed system decay within the coral lattice. A modification of the trace metal cleaning methods used for foraminifera and surface corals can significantly reduce this contamination. By counting the visible growth bands and measuring the mean age of a single septum, the extension rate of D. cristagalli was estimated to be between 0.1 and 3.1 mm/year. In a mean sense, bands appear to be precipitated annually, but this estimate has a large uncertainty. If appropriate tracer calibrations can be established, these corals are therefore suitable to record decadal or sub-decadal oceanographic changes over the course of their lifetime. The ␦ 234 U values of all modern samples from different localities and different depths are similar (mean 145.5 Ϯ 2.3‰) and indistinguishable from the data obtained from surface corals. At a precision of about Ϯ2‰, we find no structure in the oceanic profile of ␦ 234 U ratios over the top 2000 m of the water column

Misperceived pre-pregnancy body weight status predicts excessive gestational weight gain: findings from a US cohort study

<p>Abstract</p> <p>Background</p> <p>Excessive gestational weight gain promotes poor maternal and child health outcomes. Weight misperception is associated with weight gain in non-pregnant women, but no data exist during pregnancy. The purpose of this study was to examine the association of misperceived pre-pregnancy body weight status with excessive gestational weight gain.</p> <p>Methods</p> <p>At study enrollment, participants in Project Viva reported weight, height, and perceived body weight status by questionnaire. Our study sample comprised 1537 women who had either normal or overweight/obese pre-pregnancy BMI. We created 2 categories of pre-pregnancy body weight status misperception: normal weight women who identified themselves as overweight ('overassessors') and overweight/obese women who identified themselves as average or underweight ('underassessors'). Women who correctly perceived their body weight status were classified as either normal weight or overweight/obese accurate assessors. We performed multivariable logistic regression to determine the odds of excessive gestational weight gain according to 1990 Institute of Medicine guidelines.</p> <p>Results</p> <p>Of the 1029 women with normal pre-pregnancy BMI, 898 (87%) accurately perceived and 131 (13%) overassessed their weight status. 508 women were overweight/obese, of whom 438 (86%) accurately perceived and 70 (14%) underassessed their pre-pregnancy weight status. By the end of pregnancy, 823 women (54%) gained excessively. Compared with normal weight accurate assessors, the adjusted odds of excessive gestational weight gain was 2.0 (95% confidence interval [CI]: 1.3, 3.0) in normal weight overassessors, 2.9 (95% CI: 2.2, 3.9) in overweight/obese accurate assessors, and 7.6 (95% CI: 3.4, 17.0) in overweight/obese underassessors.</p> <p>Conclusion</p> <p>Misperceived pre-pregnancy body weight status was associated with excessive gestational weight gain among both normal weight and overweight/obese women, with the greatest likelihood of excessive gain among overweight/obese underassessors. Future interventions should test the potential benefits of correcting misperception to reduce the likelihood of excessive gestational weight gain.</p

A COP Fit For Children: How to support children’s participation

The climate crisis is affecting children and their rights first and worst, and will continue to affect future generations of children. Across the world, a growing global movement of children are demanding climate action, providing leadership on how the climate crisis should be addressed. Despite this, climate events and summits at all levels are rarely inclusive of children. Children are rarely invited into climate negotiations, and if they are, information is often inaccessible to them. This prevents children from participating and raising their concerns at the climate negotiations, the COPs, where important decisions on the future of climate policies are taken. “A COP Fit For Children: How to support children’s participation” sets out how the organisers of COP and states involved in COP can make the climate summit inclusive for all children in the processes leading up to COP, COP itself, and in the follow-up process

Improving PMTCT outcomes for mother-infant pairs through community-facility linkage: Results from a mixed methods study in Malawi

To improve MIP care retention in Malawi, several prevention of mother-to-child transmission of HIV (PMTCT) care delivery models have emerged to strengthen community-facility linkage (CFL), a concept defined as any “formalized connection between a health facility and the communities it serves to support improved health outcomes.” Similar to other settings in sub-Saharan Africa, three models have been widely implemented to complement Malawi’s National PMTCT Programme: 1) mentor mothers; 2) expert clients; and 3) community health workers. While the rationale underpinning these models has been substantiated by evidence generated from general antiretroviral therapy and PMTCT programs across SSA, a clear and rigorous description of each model, including characterization of supervisory structures, training, and relationships with clinical services, is currently unavailable. Equally important, the comparative impact of these models and their components on MIP care retention and other health outcomes have not been well characterized, particularly in the era of test and start. In the USAID-funded Project SOAR “Maternal-Infant Retention Study” reported here, we have attempted to address these existing evidence gaps by rigorously characterizing these community-facility linkage models and comparing their impact against each other and the “traditional” standard of care according to routinely collected health outcomes for mother-infant pairs (MIPs), including maternal retention in care and viral suppression, and infant HIV-free survival. To this end, specific objectives of this study were to: (1) establish a clear typology for CFL models by describing the main components of, and patient and key stakeholder perspectives on, three such models in Malawi; (2) describe MIP health outcomes in each model, and compare outcomes across models; and (2a) examine associations between individual components of CFL models and MIP health outcomes, controlling for confounding

Low reservoir ages for the surface ocean from mid-Holocene Florida corals

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 23 (2008): PA2209, doi:10.1029/2007PA001527.The 14C reservoir age of the surface ocean was determined for two Holocene periods (4908–4955 and 3008–3066 calendar (cal) B.P.) using U/Th-dated corals from Biscayne National Park, Florida, United States. We found that the average reservoir ages for these two time periods (294 ± 33 and 291 ± 27 years, respectively) were lower than the average value between A.D. 1600 and 1900 (390 ± 60 years) from corals. It appears that the surface ocean was closer to isotopic equilibrium with CO2 in the atmosphere during these two time periods than it was during recent times. Seasonal δ 18O measurements from the younger coral are similar to modern values, suggesting that mixing with open ocean waters was indeed occurring during this coral's lifetime. Likely explanations for the lower reservoir age include increased stratification of the surface ocean or increased Δ14C values of subsurface waters that mix into the surface. Our results imply that a more correct reservoir age correction for radiocarbon measurements of marine samples in this location from the time periods ∼3040 and ∼4930 cal years B.P. is ∼292 ± 30 years, less than the canonical value of 404 ± 20 years.NSF Chemical Oceanography program provided monetary support under grants OCE-9711326, OCE-0137207, and OCE-0551940 (to ERMD)

The Bristol Method: Green Capital Student Capital - The power of student sustainability engagement

THE BRISTOL METHODThe Bristol Method is a knowledge-transfer programme aimed at helping people in other cities understand and apply the lessons that Bristol has learned in becoming a more sustainable city, not just in 2015 but in the last decade. Each module of the Bristol Method is presented as an easy-to-digest ‘how to’ guide on a particular topic, which use Bristol’s experiences as a case study. The modules contain generic advice and recommendations that each reader can tailor to their own circumstances.This module focusses on the Green Capital: Student Capital project, and explains how the University of the West of England, Bristol (UWE) and the University of Bristol – with their respective students’ unions – have been working in partnership with the city and local communities, using Higher Education Funding Council for England Catalyst funding to promote student involvement in Green Capital activities across Greater Bristol.Student Capital created a broad programme of citywide impact during European Green Capital. It delivered a programme of student and staff engagement in enhancing sustainability within the city and has developed student and staff engagement with sustainability action. Through action research approaches it is also providing lessons for how institutions can collaborate across cities and communities to have internal and external impacts for sustainability. This report is for anyone seeking to increase sustainability engagement. In it we tell the story of the Student Capital project, explaining the processes and the outcomes, and suggesting pieces of advice and lessons for what went well, and what could have been done better or differently