The provision of paediatric and congenital heart disease services in Africa is currently less than 1% of the global surgical capacity. Coarctation of the aorta (CoA) is a common type of congenital heart disease and is influenced by the haemodynamics of blood. Patient-specific computational fluid dynamics (CFD) modelling offers valuable insights into haemodynamics in CoA, but significantly relies on the prescription of accurate outlet boundary conditions. The 3-Element Windkessel (3-EWK) model is an approach that is often used and has been shown to lead to physiologically realistic results. The accuracy of the 3-EWK is contingent on tuning of its lumped parameters (R1, R2, and C). This study quantifies the impact of measurement uncertainties from Doppler Echocardiography on the estimation of each 3-EWK lumped parameter and the resulting haemodynamic outputs from CFD across the cardiac cycle, using a stochastic approach. The results show that the resulting uncertainties in the lumped parameters do not have a significant effect on the bulk flow. This was shown by the variability of the pressure drop across the coarctation, the main clinical parameter, being less than 5%. This was similarly observed for the volume flow rate. Therefore, indicating that when using the 3-EWK model, measurement uncertainties due to Doppler echocardiography have a minor impact on the bulk flow. However, the time-varying inlet volume flow rate profile was seen to have had a more significant effect. Thus, indicating that it is of greater interest when compared to the lumped parameters.
Africa is experiencing a renewed natural resource boom. Heightened demand for the continent’s vast reserves of critical minerals and metals for green energy and technological applications, as well as its ability to serve oil and gas markets in a time of geopolitical turmoil, have triggered increased international interest and investment in African resource sectors. As in previous commodity booms, resource-rich African governments are articulating a desire to leverage natural resource wealth for economic growth and human development. Yet this promise also brings peril, as natural resource endowments have in the past generally failed to translate into improved living standards and economic growth for most resource-rich African states. Whether “this time will be different” for developmental outcomes will be shaped not just by resource endowments, but critically, by the interplay between global geopolitical dynamics, domestic political institutions, and local governance processes.
High-resolution palaeoenvironmental reconstruction is critical for identifying environmental drivers underlying the emergence of early human civilizations. To achieve this, we systematically collected representative native plants and surface sediments from tidal flats and coastal plains along the eastern coast of China. Using these samples, we established robust qualitative and quantitative relationships between phytolith assemblages and sedimentary environments. These relationships were applied to a sedimentary sequence retrieved from a Neolithic Liangzhu cultural site located on the Yangtze Delta coastline. The results show that coastal wetland sediments in East China are dominated by short-cell phytoliths derived from in situ Poaceae vegetation, alongside allochthonous bulliform phytoliths introduced from terrestrial sources and redistributed into the intertidal zone by marine processes. Consequently, the ratio of bulliform to grass short-cell phytoliths (Bull/GSSC) provides a reliable proxy for assessing the marine influence across the coastal plain. Furthermore, surface sediment phytolith assemblages exhibit strong elevation-dependent patterns along an intertidal transect in the Yangtze Delta, enabling the development of transfer functions that link phytolith composition to surface elevation. When applied to the archaeological sedimentary sequence, these transfer functions and Bull/GSSC ratio reveal pronounced interdecadal fluctuations in relative sea level and heightened frequency of extreme storm events around 5.1 cal. kyr BP, indicating increased climatic instability prior to the strengthening of ENSO dynamics in the mid-Holocene. This study therefore highlights in high precision the environmental drivers for the emergence of Liangzhu civilization around 5000 years ago.
In 2024, a comprehensive framework for the screening, diagnosis, and management of metabolic dysfunction–associated steatotic liver disease (MASLD) was incorporated in the EASL-EASD-EASO clinical practice guidelines. However, physicians often face barriers applying these recommendations in routine clinical care, especially in the Southeastern Europe, Middle East, and Africa (SEEMEA) region. As a multidisciplinary group of physicians involved in MASLD and metabolic dysfunction-associated steatohepatitis (MASH) management, our objective is to provide a practice-oriented roadmap including practical and educational considerations beyond the hepatology field that could improve patient care and support implementation of clinical guidance within the SEEMEA region. This work is informed by a narrative review and expert input obtained through structured discussions, to examine the status quo and identify key gaps in the MASLD/MASH management, unravelling the patient journey from screening and diagnosis to treatment and follow-up. Furthermore, we advise on priorities on screening triggers and, considering the limited availability of vibration-controlled transient elastography (VCTE), discuss alternative approaches to achieve accurate and timely diagnosis. Finally, following the approval of resmetirom and semaglutide 2.4 mg for MASH treatment, we review the evolving pharmacotherapy landscape and propose a “blueprint” for a specialised MASLD clinic, suggesting mandatory and optional facilities for optimised care.
The Southern Ocean accounts for >30% of the global ocean CO2 sink as a result of its solubility and biological pumps. To investigate the biological pump near Larsen C Ice Shelf (LCIS) in the Southern Ocean's western Weddell Sea, we measured the concentrations and nitrogen isotope ratios of nitrate, ammonium, and particulate organic nitrogen sampled in mid-summer 2019. From the isotope data, we estimate a mean f-ratio (i.e., fraction of primary production available for export from the mixed layer, equivalent to the extent of phytoplankton reliance on subsurface nitrate) of 0.81 +/- 0.18. This value is higher than parallel incubation-based f-ratio estimates (<= 0.5), a divergence that we ascribe to the different integration timescales of the two methods (weeks for the isotope method and hours to days for the incubations) and to a tendency for increased phytoplankton reliance on regenerated nitrogen later in the growth season. The carbon export flux estimated from the seasonal decline in nitrate concentration was >4.3 +/- 1.7 mol C m(-2) year(-1), as much as nine times that estimated for the open Antarctic Zone. Our data reveal that the waters adjacent to LCIS contribute disproportionately to the Weddell Sea's biological pump, which we attribute mainly to the effect of ice-melt on stratification and iron supply. The CO2 transferred by the biological pump into newly forming bottom waters will remain sequestered from the atmosphere for centuries.
