Breastfeeding theoretical and skills training is important for health care professionals engaging with the mother infant dyad to increase breastfeeding exclusivity and duration. The aim of this study was to evaluate the knowledge, attitudes and practices (KAPs) of health care professionals following completion of a university professional graduate programme in breastfeeding and lactation. A pre and post—educational study design was used. All students enrolled in a six month programme were invited to complete an online anonymous survey at two time points: January 2023 and July 2023. Ethical approval (LS-C-23-17) was obtained in January 2023. Descriptive statistics were utilised to report percentages and means, and independent T tests were used to report mean differences between variables on knowledge, attitude and practices. All students completed the module. The pre survey participant response rate was n = 55 (92.82%) and the post survey participant response rate n = 33 (60%). Comparison of the pre and post questionnaire report nine statistically significant results following completion of the university breastfeeding and lactation programme. Knowledge scores increased specifically with higher mean knowledge scores for reporting “I am confident with my knowledge about breastfeeding” and statistically significant mean difference of 0.29 following completion of the module (95% CI, 0.13 to 0.45) (t (64) = 3.59, p = 0.001). The programme evaluation identifies the importance of a professional graduate breastfeeding and lactation education programme for interdisciplinary health care professionals increasing knowledge, attitudes and practices and ultimately increasing breastfeeding rates in the short and long term, with improved maternal and child health outcomes.
Abstract Analyses of olivine-, pyroxene- and plagioclase-hosted melt (now preserved as glass) inclusions (MI) in submarine glasses and subaerial scoria from seven volcanoes along the volcanic front of the Tonga arc provide the first comprehensive dataset including volatile contents (H2O, CO2, S, Cl and F) for this arc. Maximum water contents at each volcano are typical (3–5 wt %) of other arc volcanoes worldwide, and within each volcano, water generally correlates with sulfur, consistent with degassing but not diffusive re-equilibration. The Tonga arc is notable for the eruption of magmas sourced from strongly depleted upper mantle, including boninites in the northern half of the active arc. A key question has been whether such boninites are derived from high degrees of melting actively occurring under the arc, driven by high mantle temperatures and water contents, or from high integrated degrees of melting including melting of depleted mantle in the backarc. This study supports the latter view, based on sub-arc mantle melt fractions of 17–23%, calculated from primary melt water contents and mantle-melt thermobarometry. Such fractions are not high enough to generate boninites from a typical, fertile mantle source in a single melting stage, and melt fractions do not increase north of 22°S, where the boninitic magmas appear. Instead, the northern Tonga arc boninites reflect high cumulative degrees of melting (>30%, with respect to fertile mantle) and occur along the volcanic front where adjacent backarc spreading is fast, proximal and mature. Slab tracers such as the Ba/La ratio peak at around 20–21°S, in the central part of the Tonga arc. A Ba/La peak also appears at about the same latitude in the Lau backarc basin. This peak is consistent with the coolest slab temperatures beneath the arc and backarc at this latitude, as the slab warms to the north due to an increase in mantle potential temperature, and to the south due to less heat extraction from melting. A new concept developed here is cooling of the mantle wedge by melting, due to the supply of the heat of fusion and melt removal. Such a process can cool the mantle by more than 100 degrees, and thus affect slab heating as well. We find a critical distance of slab influence in the Lau spreading centers; back-arc magmas erupted >70 km from the arc are >210 km above the slab, beyond the point of slab dehydration, and show no enrichment in Ba/La. The coupled dynamics of the Tonga arc-Lau basin are rich in their connections, and demonstrate how melting processes beneath the back-arc and arc can affect slab processes, which in turn can affect the composition of fluids that feed the arc and backarc.
Tofua volcano is situated midway along the Tonga oceanic arc and has undergone two phases of ignimbrite-forming activity. The eruptive products are almost entirely basaltic andesites (52·5–57 wt % SiO2) with the exception of a volumetrically minor pre-caldera dacite. The suite displays a strong tholeiitic trend with K2O <1 wt %. Phenocryst assemblages typically comprise plagioclase + clinopyroxene ± orthopyroxene with microlites of Ti-magnetite. Olivine (Fo83–88) is rare and believed to be dominantly antecrystic. An increase in the extent and frequency of reverse zoning in phenocrysts, sieve-textured plagioclase and the occurrence of antecrystic phases in post-caldera lavas record a shift to dynamic conditions, allowing the interaction of magma batches that were previously distinct. Pyroxene thermobarometry suggests crystallization at 950–1200°C and 0·8–1·8 kbar. Volatile measurements of glassy melt inclusions indicate a maximum H2O content of 4·16 wt % H2O, and CO2–H2O saturation curves indicate that crystallization occurred at two levels, at depths of 4–5·5 km and 1·5–2·5 km. Major and trace element models suggest that the compositions of the majority of the samples represent a differentiation trend whereby the dacite was produced by 65% fractional crystallization of the most primitive basaltic andesite. Trace element models suggest that the sub-arc mantle source is the residuum of depleted Indian mid-ocean ridge basalt mantle (IDMM-1% melt), whereas radiogenic isotope data imply addition of 0·2% average Tongan sediment melt and a fluid component derived from the subducted altered Pacific oceanic crust. A horizontal array on the U–Th equiline diagram and Ra excesses of up to 500% suggest fluid addition to the mantle wedge within the last few thousand years. Time-integrated (226Ra/230Th) vs Sr/Th and Ba/Th fractionation models imply differentiation timescales of up to 4500 years for the dacitic magma compositions at Tofua.
We have calculated slab fluid temperatures for 51 volcanoes in 10 subduction zones using the newly developed H 2 O/Ce thermometer. The slab fluid compositions were calculated from arc eruptives, using melt inclusion‐based H 2 O contents, and were corrected for background mantle contributions. The temperatures, adjusted to h , the vertical depth to the slab beneath the volcanic arc, range from ∼730 to 900°C and agree well (within 30°C on average for each arc) with sub‐arc slab surface temperatures predicted by recent thermal models. The coherence between slab model and surface observation implies predominantly vertical transport of fluids within the mantle wedge. Slab surface temperatures are well reconciled with the thermal parameter (the product of slab age and vertical descent rate) and h . Arcs with shallow h (∼80 to 100 km) yield a larger range in slab surface temperature (up to ∼200°C between volcanoes) and more variable magma compositions than arcs with greater h (∼120 to 180 km). This diversity is consistent with coupling of the subducting slab and mantle wedge, and subsequent rapid slab heating, at ∼80 km. Slab surface temperatures at or warmer than the H 2 O‐saturated solidus suggest that melting at the slab surface is common beneath volcanic arcs. Our results imply that hydrous melts or solute‐rich supercritical fluids, and not H 2 O‐rich aqueous fluids, are thus the agents of mass transport to the mantle wedge.
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