Université Professionnelle d'Afrique

ABSTRACTThe Congo Basin and its contiguous forests harbor globally significant carbon stocks, estimated at 65 gigatons of C (GtC) above and belowground. Despite rising temperatures and intensifying droughts, they have remained a carbon sink, albeit weak: 0.26–0.50 GtC yr.−1 carbon uptake since 1980. However, these forests' carbon stocks and fluxes, including gross primary productivity, respiration, net primary productivity, and riverine carbon transport, remain poorly quantified. This limits understanding of the region's role in the global carbon cycle, its vulnerability to environmental change, and its potential as a long‐term carbon sink. We review and quantify Congo Basin and contiguous forest carbon stocks and fluxes and synthesize the current knowledge on how key global change drivers shape the region's carbon cycle. We find limited responses to long‐term precipitation variability, but declining stocks and fluxes in response to long‐term and increasing temperature and drought frequency. Land cover and land use changes, largely driven by small‐scale agriculture, logging, and agro‐industrial expansion, reduce carbon stocks, ecosystem structure and functioning, and animal‐mediated ecosystem services. In contrast, large‐scale savanna biomass burning delivers phosphorus and nitrogen to Congo Basin forests via cross‐equatorial winds, providing additional nutrients and supporting carbon sequestration. In situ studies suggest that CO2 fertilization has increased intrinsic water‐use efficiency, although its effects may be modulated by climate change, and its impacts on biomass accumulation remain uncertain. Legacy effects from historical land use and climate change likely shaped present‐day vegetation structure, yet their relative influence is unclear. High‐resolution carbon monitoring, improved remote sensing, and strengthened in situ measurement networks are needed to quantify the impacts of these key drivers and their interactions on the Central African carbon cycle. This is needed to inform conservation strategies and advance understanding of the region's future as a carbon sink under global change pressures.

Interfering RNA therapies (RNAi) have changed the management of patients with hyperoxaluria type 1 (PH1); data in dialysis remain scarce. A PH1 teenager undergoing intensive hemodiafiltration received lumasiran. POx levels almost halved during the loading phase (98 to 52µmol/L), but rebound occurred when doses were quarterly-spaced, with POx at 94 µmol/L at 5 months. Lumasiran injections were therefore performed monthly, allowing adequate POx control (52µmol/L) and isolated kidney transplantation. We also evaluated POx in 26 non-PH1 children with current dialysis techniques at a median(range) age of 10.9 (2.6-17.0) years, time on dialysis 14 (0-52) months, and POx 35 (8-125) µmol/L; residual diuresis was associated with lower POx. Circulating glycolate levels were normal in non-PH1 patients. Intensification of lumasiran therapy is possible in dialysis and improves POx levels before kidney transplantation; POx levels in non-PH1 pediatrics patients in dialysis are provided to improve decision making in transplantation.

Introduction: The SARS-CoV-19 pandemic affected the whole world, with a particularly high and severe incidence in patients with co-morbidities such as type 2 diabetes (T2DM). The SARS-CoV-2 variants, Delta and Omicron, posed an additional challenge in the management of these patients because of their virulence and high transmissibility. Objective: To assess the disturbance of certain biomarkers in COVID-19-positive T2DM patients in Pointe-Noire. Methods: We performed a descriptive cross-sectional study on a cohort of 206 type 2 diabetic patients affected by COVID-19. Blood samples were taken for analysis of biomarkers (CBC, ESR, CRP, GLY, and HbA1c, lipid profile, urea and creatinine). RNA was extracted from nasopharyngeal samples and PCR was performed to determine the presence of Delta and Omicron variants. Results: The mean age of our patients was 56.33 ± 12 years. The Delta variant was the most common 132 (64.08%), followed by the other variants 57 (27.67%) and Omicron 17 (8.25%). We observed significant disturbances (p<0.05) in biomarkers as a function of Delta and Omicron variants concerning: TC, TG, HDL, LDL, DDI, VS, CRP, GLY, and HbA1c. Conclusion: We identified the Delta variant as the most frequent in the diabetic population studied. Almost all biological markers studied were disrupted during COVID-19 infection in the type 2 diabetic population.

The COVID-19 pandemic has impacted population health around the globe, directly and indirectly. The objective of this study was to document changes in HIV care associated with the COVID-19 pandemic at selected clinics in Central Africa, along with clinic-level strategies for minimizing disruptions in HIV care and treatment for people with HIV (PWH). A 51-item questionnaire on COVID-19 pandemic-associated changes in HIV service delivery was completed by clinicians involved in HIV care at 21 clinics in five countries participating in Central Africa International epidemiology Databases to Evaluate AIDS (CA-IeDEA). The survey was completed at two timepoints: June-July 2020 and October 2020 to February 2021. Descriptive statistics were used to characterize changes in HIV care and related services. While 81% of sites reported at least one negative consequence of COVID-19 for clinic operations during the first survey, none reported suspending antiretroviral therapy (ART) initiation services for new patients, and 24% reported adopting telemedicine. In the follow-up survey, fewer sites (48%) reported at least one disruption to clinic operations, and more sites reported mitigation strategies, including expanding rapid ART initiation services and providing extra supplies of ART medications to reduce visit frequency. In the follow-up survey, more sites, especially in Rwanda, reported stockouts of commodities, including HIV and viral load testing and HIV pre-exposure prophylaxis. More than one-fifth of sites reported stockouts of second- or third-line ART at each survey timepoint. While the initial wave of the COVID-19 pandemic resulted in concerning disruptions to HIV service delivery at CA-IeDEA sites, most of these disruptions attenuated over time, and many sites introduced measures to help PWH avoid frequent visits to the clinic for care and medications. The impact of HIV commodity stockouts and clinic mitigation strategies on treatment outcomes needs to be assessed.

Plant and/or crop growth rely on nutrient dynamics driven by specific soil biota in different environments. This mini-review aims to provide an overview of interactions between soil organisms, nutrient dynamics, and C sequestration. To this end, we investigated published results from three forest plantations (eucalyptus monocultures and mixed plantations with N2-fixing acacia) on tropical nutrient-poor soils. One case study is located in Central Africa (Congolese coastal plains) and two others in South America (Southeastern Brazil). Overall, the studies showed that soil biota activity exerted positive effects on (i) C accretion, as both soil carbon and belowground and aboveground biomass are driven and enhanced by soil biota; and (ii) on nutrient dynamics and biogeochemical cycles in nutrient-poor soil of tropical ecosystems, which are boosted following C accumulation. On the other hand, the pedoclimatic environment may potentially impact soil functioning of mixed-species plantations through its influence on the composition and activity of bacterial communities. Regardless of the potential risk of acacia invasiveness, benefits such as pulp, fuelwood, electric pole and non-timber products supply, have been reported in Central Africa. We, therefore, conclude that including N2 fixing trees in forestry plantations as reported in this mini-review helps strengthen the links between soil biota, nutrient and SOC dynamics in mixed-species plantations on tropical nutrient-poor soils.

BackgroundLand-use change and forest management may alter soil organic matter (SOM) and nutrient dynamics, due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations established in the Congolese coastal plains to improve soil fertility and tree growth. Eucalypt trees were expected to benefit from N2 fixed by acacia. However, some indicators suggest a perturbation in SOM and P dynamics might affect the sustainability of the system in the medium and long term. In tropical environments, most of the nutrient processes are determined by the high rates of organic matter (OM) mineralization. Therefore, SOM stability might play a crucial role in regulating soil-plant processes. In spite of this, the relationship between SOM quality, C and other nutrient dynamics are not well understood. In the present study, OM quality and P forms in forest floor and soil were investigated to get more insight on the C and P dynamics useful to sustainable management of forest plantations.MethodsThermal analysis (differential scanning calorimetry (DSC) and thermogravimetry (TGA)) and nuclear magnetic resonance (solid state 13C CPMASS and NMR and 31P-NMR) spectroscopy have been applied to partially decomposed forest floor and soils of pure acacia and eucalypt, and mixed-species acacia-eucalypt stands.ResultsThermal analysis and 13C NMR analysis revealed a more advanced stage of humification in forest floor of acacia-eucalypt stands, suggesting a greater microbial activity in its litter. SOM were related to the OM recalcitrance of the forest floor, indicating this higher microbial activity of the forest floor in this stand might be favouring the incorporation of C into the mineral soil.ConclusionsIn relation with the fast mineralization in this environment, highly soluble orthophosphate was the dominant P form in both forest floor and soils. However, the mixed-species forest stands immobilized greater P in organic forms, preventing the P losses by leaching and contributing to sustain the P demand in the medium term. This shows that interactions between plants, microorganisms and soil can sustain the demand of this ecosystem. For this, the forest floor plays a key role in tightening the P cycle, minimizing the P losses.

This paper will seek to highlight and discuss the questioning that the Cameroonian philosopher Marcien Towa makes of the Black African Philosophical thought from decade of 1960 and 1970 and the paths that it points to the realization of Philosophy. At first, we will present the Towa’s diagnosis about the ways that the African Philosophical thought took after the end of the colonial process. In this questioning, he especially criticized the thought of Leopold Sedar Senghor, who provides a blackness type that has as trap his own theoretical articulation, dualistic and universal and is based on the ethnoPhilosophy, which maximizes the view that Europe contributes for the construction of human history with its reason and Africa, with its emotion and mysticism. Towa points a way to abandon this perspective of blackness, with the disclosure of rationality found in the different African cultures’ structure, as he presents an Africa that contributes rationally and culturally with the universal history.

Take these eight steps to make soils more resilient to drought, produce more food and store emissions, urge Cornelia Rumpel and colleagues. Take these eight steps to make soils more resilient to drought, produce more food and store emissions, urge Cornelia Rumpel and colleagues.

Pediatric AIDS is still a public health issue. In order to improve the care of children living with HIV, a study was carried out between January and December 2014, that is in 12 months at University Center Hospital (UCH) of Brazzaville, in the two Ambulant Treatment Centers (ATCs) of Brazzaville and Pointe-Noire, In three general hospitals and seven base hospitals. Heads of centers and follow-up files of children aged 0 to 15 constituted the target population. The study variables concern the provision of care, the organization of structures and personnel, and data management. Thirteen health facilities, 13 heads of centers and 520 medical files were selected. HIV care was effective in nine out of eleven departments, only the two CTAs offered the entire package of activities. The diagnosis was made in WHO stage 3 in 433 cases (83.3%), the pre-therapeutic assessment in 246 cases (47.2%); Psychological care in 84 cases (16.1%) whose 80 (95.2%) in the ACT, nutritional management in 4 cases (0.7%). Nine out of 13 centers did not have computer tools or materials for patient information and education; No center had sufficient staff. The dispensation of Anti-retroviral drugs (ARDs) is not based on any standard and the safety conditions of the laboratory providers are not guaranteed. The importance of the observed dysfunction makes it necessary to improve the general conditions of care.