Effets de six composts sur les réponses physiologiques, biochimiques et agronomiques du niébé Vigna unguiculata L. Walp var. KVX. 61.1. au déficit hydrique

Un déficit hydrique sévère a été imposé par suspension de l’arrosage à deux stades de développement à une variété de niébé Vigna unguiculata L. Walp var. KVX. 61.1 cultivée en pot à l’air libre. Le sol de culture est un Lixisol Ferrique amendé par six types de composts fabriqués à partir de mélanges de déchets urbains solides composés de déchets verts (DV), de déchets d’abattoir (DA), de déchets de cuisine (DC) selon les compositions suivantes: C1=40%DV+60%DA; C2=40%DV+40%DA+20%DC; C3=40%DV+30%DA+30%DC; C4=40%DV+20%DA+40%DC; C5=40%DV+60%DC; C6=100%DV. Les effets de ces six composts sur le potentiel hydrique, la fuite d’électrolyte, la teneur en amidon des feuilles et sur quelques paramètres agronomiques ont été évalués sur les plantes stressées en comparaison avec les plantes témoins. Les résultats indiquent des valeurs du potentiel hydrique foliaire très faibles et une réduction de la teneur en amidon des feuilles pour les plantes des composts C2, C3, C4, et C5. Ces dernières présentent des intégrités membranaires plus affectées comparativement aux plantes du sol témoin et celles des composts C1 et C6. Les composts C2, C3, C4 et C5 favorisent le développement des racines et augmentent le rendement en graines du niébé en condition de déficit hydrique. Ce qui justifie l’intérêt du compostage des déchets de cuisine.Mots clés : niébé, déficit hydrique, compost, déchets urbains solide

Separating autotrophic respiration due to roots from soil heterotrophic respiration in an agroforestry parkland system in Saponé, Burkina Faso

Soil respiration is the largest component of ecosystem respiration but little is known about it and its components in parkland systems. We therefore conducted an experiment to estimate the amount of CO2 respired and to partition it into soil, tree root and crop root contributions in parkland systems in Burkina Faso. Three factors effects were estimated: pruning, species and presence of tree canopy. Pruning showed no significant effect on soil respiration. The soil respiration was significantly higher under Parkia biglobosa (1.54 g CO2 m-2 h-1 against 0.93 in the open area) than under Vitellaria paradoxa (0.98 g CO2 m-2 h-1 against 0.52 in the open area). The autotrophic respiration associated with the P. biglobosa system due to sorghum roots was 0.37 g CO2 m-2 h-1 and due to tree roots was 0.61. For the V. paradoxa system, the figures were 0.13 g CO2 m-2 h-1 for sorghum roots and 0.46 for tree roots. We observed higher CO2 emissions from under trees crowns than in open areas owing to higher tree-root respiratory activities, and higher water and organic matter contents. However, further studies are needed to discover if these low values of soil CO2 fluxes from parklands translate into higher amounts of carbon fixed than emitted taking into consideration the seasonal variations.Keywords: Carbon balance, CO2 flux, carbon-sink, carbon-source

Combined clinical audits and low-dose, high-frequency, in-service training of health care providers and community health workers to improve maternal and newborn health in Mali: Protocol for a pragmatic cluster randomized trial

Background: Although most births in Mali occur in health facilities, a substantial number of newborns still die during delivery and within the first 7 days of life, mainly because of existing training deficiencies and the challenges of maintaining intrapartum and postpartum care skills.Objective: This trial aims to assess the effectiveness and cost-effectiveness of an intervention combining clinical audits and low-dose, high-frequency (LDHF) in-service training of health care providers and community health workers to reduce perinatal mortality.Methods: The study is a three-arm cluster randomized controlled trial in the Koulikoro region in Mali. The units of randomization are each of 84 primary care facilities. Each trial arm will include 28 facilities. The facilities in the first intervention arm will receive support in implementing mortality and morbidity audits, followed by one-day LDHF training biweekly, for 6 months. The health workers in the second intervention arm (28 facilities) will receive a refresher course in maternal neonatal and child health (MNCH) for 10 days in a classroom setting, in addition to mortality and morbidity audits and LDHF hands-on training for 6 months. The control arm, also with 28 facilities, will consist solely of the standard MNCH refresher training delivered in a classroom setting. The main outcomes are perinatal deaths in the intervention arms compared with those in the control arm. A final sample of approximately 600 deliveries per cluster was expected for a total of 30,000 newborns over 14 months. Data sources included both routine health records and follow-up household surveys of all women who recently gave birth in the study facility 7 days postdelivery. Data collection tools will capture perinatal deaths, complications, and adverse events, as well as the status of the newborn during the perinatal period. A full economic evaluation will be conducted to determine the incremental cost-effectiveness of each of the case-based focused LDHF hands-on training strategies in comparison to MNCH refresher training in a classroom setting.Results: The trial is complete. The recruitment began on July 15, 2019, and data collection began on July 23, 2019, and was completed in November 2020. Data cleaning or analyses began at the time of submission of the protocol.Conclusions: The results will provide policy makers and practitioners with crucial information on the impact of different health care provider training modalities on maternal and newborn health outcomes and how to successfully implement these strategies in resource-limited settings.Trial registration: ClinicalTrials.gov NCT03656237; https://clinicaltrials.gov/ct2/show/NCT03656237.International registered report identifier (irrid): DERR1-10.2196/28644

Immunogenicity of Fractional Doses of Tetravalent A/C/Y/W135 Meningococcal Polysaccharide Vaccine: Results from a Randomized Non-Inferiority Controlled Trial in Uganda

Meningitis are infections of the lining of the brain and spinal cord and can cause high fever, blood poisoning, and brain damage, as well as result in death in up to 10% of cases. Epidemics of meningitis occur almost every year in parts of sub-Saharan Africa, throughout a high-burden area spanning Senegal to Ethiopia dubbed the “Meningitis Belt.” Most epidemics in Africa are caused by Neisseria meningitidis (mostly serogroup A and W135). Mass vaccination campaigns attempt to control epidemics by administering meningococcal vaccines targeted against these serogroups, among others. However, global shortages of these vaccines are currently seen. We studied the use of fractional (1/5 and 1/10) doses of a licensed vaccine to assess its non-inferiority compared with the normal full dose. In a randomized trial in Uganda, we found that immune response and safety using a 1/5 dose were comparable to full dose for three serogroups (A, Y, W135), though not a fourth (C). In light of current shortages of meningococcal vaccines and their importance in fighting meningitis epidemics around the world, we suggest fractional doses be taken under consideration in mass vaccination campaigns

Effet du régime hydrique sur les rendements du gombo en culture de contre-saison

L’étude à pour but de mettre en évidence la période de contre-saison favorable à la culture du gombo (Abelmoschus esculentus) et de déterminer la bonne fréquence d’arrosage. Pour cela, deux essais ont été réalisés sur trois écotypes 1 ; 19 et 22: le premier pendant la période froide (décembre-mars 2005) et le second durant la période chaude (avril-juillet). Trois fréquences d’arrosage ont été appliquées à la culture à partir du 21ème jour après semis (JAS) de chaque essai. La teneur en eau des feuilles par rapport à la masse sèche, la hauteur moyenne des plantes à la récolte et les paramètres de production ont été mesurés. Des résultats obtenus, il ressort que la teneur en eau des feuilles par rapport à la matière sèche des trois écotypes étudiés (écotypes 1, 19 et 22) est significativement affectée par le régime hydrique. En outre, la croissance du gombo est significativement réduite durant la période froide (décembre-mars). L’analyse du rendement en relation avec la fréquence d’arrosage montre que l’arrosage chaque deux jours est bénéfique car non seulement, il permet d’avoir de bons rendements mais réduit également le gaspillage d’eau. Indépendamment du régime hydrique et de la période de culture, l’écotype 22 s’est révélé être le plus productif.The study aims to highlight the favorable period of against-season for the okra culture and to determine the good frequency of watering. For that, two tests were carried out on three ecotypes 1; 19 and 22: the first during the cold period (December-March) and the second during the hot period (April-July). Three frequencies of watering are applied to the culture starting from the 21st JAS of each test. The water content of the sheets compared to the dry mass, the average height of the plants to harvest and the parameters of production are measured. Results obtained, showed that during the cold period, water content in leaves in comparison to dried matter of ecotypes studied (ecotypes 1; 19; 22) was significantly affected by the water regime. On the other hand, water regime hasn’t significant effect on the water content of leaves. Moreover, the growth of okra is strongly slowed during the cold period. The analysis of yield in relation with water regime, show that watering all two days is beneficial because it permits to have appreciable yield but reduced water’s waste. Independently of watering’s frequency and farming period, ecotype 22 seems to be more productive.Mots clés : contre-saison, fréquence d’arrosage, gombo; rendement

Influence des organes receveurs sur la distribution du carbone photosynthetique entre l'amidon et le saccharose dans la feuille de soja

National audienceThe influence of translocations towards sinks on photosynthetic carbon distribution between foliar starch and sucrose was studied in soybean plants (Glycine max L Merr), cv Kingsoy. After foliar 14CO2 incorporation in situ, the radiocarbon distribution between starch and sucrose and the 14C translocation towards sinks were investigated during the hours following incorporation (fig 1). When the export rate increased or was stimulated by fertilising irrigations, less radiocarbon was incorporated into starch (fig 2). If the translocation decreased, more radiocarbon was used for starch synthesis and the leaf accumulated starch and sucrose (table II). Experiments on source/sink modifications corroborated these data (fig 3). Nutrient solution overloaded with minerals decreased the export rate and increased leaf sucrose content (fig 4); sucrose phosphate synthase activity weakened (table III) and, in spite of small F-2,6-P content facilitating sucrose formation, more photosynthetic carbon was directed towards starch.L’influence des transferts vers les organes receveurs sur la distribution foliaire du carbone photosynthétique entre l’amidon et le saccharose est étudiée sur des plants de soja (Glycine max, L Merr), variété Kingsoy. Après des incorporations foliaires de 14CO2 effectuées in situ, la répartition du radiocarbone entre les 2 glucides et son transfert vers les organes receveurs sont précisés aux cours des h qui suivent l’incorporation. Lorsque les migrations sont importantes ou stimulées par des irrigations fertilisantes, peu de radiocarbone est intégré dans l’amidon. Inversement, si les transferts sont ralentis, davantage de carbone fixé est utilisé pour la synthèse de l’amidon; ce dernier, ainsi que le saccharose, s’accumulent dans la feuille. Ces résultats sont confirmés par des expériences où l’on modifie artificiellement le rapport source/puits. En présence d’une alimentation minérale déséquilibrée, les transferts d’assimilats sont fortement réduits et la teneur foliaire en saccharose augmente; l’activité de la saccharose phosphate synthase diminue; et, malgré une faible teneur en F-2,6-P favorable à la formation du saccharose, davantage de carbone photosynthétique est orienté vers l’amidon