Summary On Aug 25 2020, the Africa Regional Commission for the Certification of Poliomyelitis Eradication declared that the WHO African region had interrupted transmission of all indigenous wild polioviruses. This declaration marks the African region as the fifth of the six WHO regions to celebrate this extraordinary achievement. Following the Yaoundé Declaration on Polio Eradication in Africa by heads of state and governments in 1996, Nelson Mandela launched the Kick Polio out of Africa campaign. In this Health Policy paper, we describe the long and turbulent journey to the certification of the interruption of wild poliovirus transmission, focusing on 2016–20, lessons learned, and the strategies and analyses that convinced the Regional Commission that the African region is free of wild polioviruses. This certification of the WHO African region shows the feasibility of polio eradication in countries with chronic insecurity, inaccessible and hard-to-reach populations, and weak health systems. Challenges have been daunting and the sacrifices enormous—dozens of health workers and volunteers have lost their lives in the pursuit of a polio-free Africa.
Croissance et production de matières de Typha australis (SCHUM. et THON.) soumis à différents niveaux d'immersion. que l'immersion est forte. Ce qui permet à la plante de maximiser sa croissance. Cette étude contribue à la compréhension des mécanismes de croissance et d'allocation de matières dans les différentes parties de Typha australis. Ceci pourrait limiter son expansion et éventuellement son éradication. Mots clefs : croissance, rhizome, Typha, immersion, matières sèches, parties souterraines, parties aériennes. Growth and matters production of Typha australis (SCHUM. and THON) subject to different levels of immersion ABSTRACT Objective: Invasive plants cause a dysfunction of ecosystems particularly in wetlands for agricultural use such as the "Niayes" where the water level fluctuates during the year. The present study aims at assessing the growth and the production of matters of Typha australis when the rhizomes are subject to different levels of immersion in experimental conditions from two hypothesis: 1-growth plants from rhizomes is affected by the level of immersion; 2-allocations of materials in different parts of the plant are influenced by the level of immersion. Methodology and Results: The test was carried out under experimental conditions in containers filled with sand, of the "Niayes" area, whose characteristics are defined. Typha plants harvested in the area were transplanted into containers. Three levels of water supply were used: a water-saturated level chosen from the withdrawal curve; two levels of water column to 50 mm and 100 mm. Parameters such as height, relative growth rate, and fresh matter of the aerial parts are even higher than the level of immersion is important with significant differences. The dry matter of the underground parts is distributed preferentially in the upper horizons for the 3 levels of water supply. In saturated environment, it has an even distribution between the two horizons. In the 50 and 100 mm levels of immersion, redistribution of the underground system is established. Ratio PA / PS decrease during the experiment with the immersion level with significant differences between saturated level and the two others levels (p <0.05). Typha australis concentrates more matters in the underground part to maximize its growth. Conclusion and Application: These results show that some morphological parameters and production matters of Typha australis are all higher than the environment is in immersion. This growth is due to the allocation of matters produced in the underground parts that are also particularly important that immersion is strong. This allows Typha australis to maximize growth. This study contributes to the understanding of the growth mechanisms and matter allocation in different parts of Typha australis. This could limit its expansion and possible eradication.
RESUMEL'influence des régimes d'alimentation hydrique sur les variations du diamètre des tiges et la réponse de jeunes plants de Acacia senegal (L.) Wildd après une réhydratation a été appréciée par la méthode des capteurs. 1-En condition d'alimentation hydrique optimale, Acacia senegal (L.) Wildd subit des variations nycthémérales: déshydratation au cours de la journée et double récupération hydrique pendant la nuit et en début de matinée. 2-L'état hydrique du sol détermine les variations d'amplitude des diamètres des jeunes plants qui sont d'autant plus importantes que la contrainte est sévère. 3-Les micro-variations des diamètres déterminent la croissance des jeunes plants qui est d'autant plus importante que le traitement est humide. 4-La réhydratation dans les traitements hydriques modéré et sévère se traduit par une reprise de la croissance avec des récupérations nocturnes en condition modérée.
Peanut (Arachis hypogaea, L.) is an annual papilionaceous oilseed legume cultivated on nearly 25 million hectares in tropical and temperate zones due to its remarkable plasticity to temperature and water requirements. In Senegal, peanut is produced in rural areas where they are the main source of agricultural income. Variety 73-33 is cultivated in the river valley and the groundnut basin is subject to the influence of salinization affecting four of Senegal's ecogeographic zones. Studies conducted with randomized full-block experimental set-up in the laboratory and under semi-controlled greenhouse conditions have shown the effect of different concentrations of NaCl on the peanut variety 73-33: 0mM; 25mM; 50mM; 100mM; 200mM; 300mM; 400mM; 500mM for germination and 0mM; 25mM; 50mM; 100mM for growth growth and chlorophyll production. The parameters which were measured are: the germination rate (ten days after sowing), the number of nodules, the number of gynophores, the dry biomass and the production of chlorophyll at twenty, forty and seventy-five days after sowing. Germination is significantly negatively affected from 400mM. Twenty days after sowing there is a significant difference between the control and the other treatments for the production of chlorophyll a (Chla) only. Forty days after sowing, the production of chlorophyll a and total chlorophyll shows a very highly significant difference between all the treatments. The dry biomass only shows a significant difference from 100mM. Seventy-five days after sowing, the dry biomass and the number of gynophores are significantly reduced by the salinity from 25mM.
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