Afforestation/Reforestation Based on Gmelina Arborea (Verbenaceae) in Tropical Africa: Floristic and Structural Analysis, Carbon Storage and Economic Value (Cameroon)

The study was carried out in three selected plantations. Sampling was made infive 100x20 m2 plots per site. Overall, 32 species, 36 genera and 17 families were surveyed. Hymenocardia acida, Combretum adenogonium, Daniellia oliveri, Entada africana, Terminalia macroptera, T. laxiflora, Lannea schimperi, Lophira lanceolata, Maytenus senegalensis, Ochna schweinfurthiana, Protea madiensis, Psorospermum senegalense, Piliostigma thonningii, Sarcocephalus latifolius and Securidaca longepedunculata were the most important species. The richness index ranged from 2.53±0.05-7.74±0.03. Shannon index was 3 in all sites. Density ranged from 98±2.01-253±10.23 stems/ha. Basal area was statistically significant among the sites (p70 %). The vertical structure showed three types of figures; L shape, symmetrical bell shape and unsymmetrical bell shape. These structures confirmed a good regeneration of timbers in the sites. There was a positive correlation of the species dispersal in the sites (p<0.001). The amount of AGB was 23.50±0.38 t C/ha. The amount of C sequestration was 86.28±16.57 t CO2eq/ha. The ecosystem service payments ranged between 258.87±24.88-8629.25±248.16 €/ha with the lowest values for CDM price and the highest for REDD+price. A financing of such projects is required in the frame of creating adaptation and attenuation measures to global warming effects

Correlation between Associated Trees, Cocoa Trees and Carbon Stocks Potential in Cocoa Agroforests of Southern Cameroon

This study was conducted in the Cocoa Agro-Forests (CAF) of Mengomo’s locality. The aim was to evaluate the influence of some factors on carbon stocks. The sampling was done in 30 plots of 25 x 25 m 2 in which all trees with a dbh?10 cm were inventoried. The Shannon, Simpson and Evernnessindexes were calculated to characterize the diversity of trees associated with cocoa. 62 species belonging to 48 genera and 27 families were identified, the Anacardiaceae, Moraceae, Caesalpiniaceae,  Mimosaceae and Rutaceae, were revealed the most diverse families, with 5 species each. Shannon’s (3.66), Evernness’s (0.76) and Simpson’s (0.96) indexes have reflected a low diversity, dominated by some fewspecies. The average density of cocoa trees is 1028 trees/ha. They store about 22.51±5.86 Mg C/ha. Associated trees stored 124.20±60.05Mg C/ha for tree density of 113 trees/ha. These CAF sequestered about 146.71Mg C/ha. The multiple correspondence analyses showed that carbon stocks in the CAF are positively correlated with the associated trees and the age of the CAF and negatively correlated with the abundance of cocoa trees. The biomass of cocoa is independent of the associated trees, but is inversely related to the density of the associated trees

High efficacy of microbial larvicides for malaria vectors control in the city of Yaounde Cameroon following a cluster randomized trial

The rapid expansion of insecticide resistance and outdoor malaria transmission are affecting the efficacy of current malaria control measures. In urban settings, where malaria transmission is focal and breeding habitats are few, fixed and findable, the addition of anti-larval control measures could be efficient for malaria vector control. But field evidences for this approach remains scarce. Here we provide findings of a randomized-control larviciding trial conducted in the city of Yaoundé that support the efficacy of this approach. A two arms random control trial design including 26 clusters of 2 to 4 km2 each (13 clusters in the intervention area and 13 in the non-intervention area) was used to assess larviciding efficacy. The microbial larvicide VectoMax combining Bacillus thuringiensis var israelensis (Bti) and Bacillus sphaericus in a single granule was applied every 2 weeks in all standing water collection points. The anopheline density collected using CDC light traps was used as the primary outcome, secondary outcomes included the entomological inoculation rate, breeding habitats with anopheline larvae, and larval density. Baseline entomological data collection was conducted for 17 months from March 2017 to July 2018 and the intervention lasted 26 months from September 2018 to November 2020. The intervention was associated with a reduction of 68% of adult anopheline biting density and of 79% of the entomological inoculation rate (OR 0.21; 95% CI 0.14–0.30, P < 0.0001). A reduction of 68.27% was recorded for indoor biting anophelines and 57.74% for outdoor biting anophelines. No impact on the composition of anopheline species was recorded. A reduction of over 35% of adult Culex biting densities was recorded. The study indicated high efficacy of larviciding for reducing malaria transmission intensity in the city of Yaoundé. Larviciding could be part of an integrated control approach for controlling malaria vectors and other mosquito species in the urban environment

Community intervention to reduce social isolation in older adults in disadvantaged urban areas: study protocol for a mixed methods multi-approach evaluation

Background: The proportion of older people has dramatically increased in recent decades. Moreover, social and demographic trends show a global increase of older people at risk of loneliness and lack of social relationships. The objective of this study was to evaluate the process, the effectiveness and the cost-effectiveness of a planned 22 weekly group sessions called School of Health for Older People to reduce social isolation. Methods: This is a mixed methods multi-approach evaluation that includes: 1) A qualitative evaluation among coordinators and participants taking part in the intervention, through in depth-interviews and focus groups, respectively. The main topics covered will be positive and negative aspects of the intervention, suggestions for its improvement, opinions on different aspects of the intervention, and perceived benefits; 2) A quantitative quasi-experimental design, comparing a group of individuals taking part in the intervention with another group with similar characteristics not receiving the intervention. Data will be collected at the beginning and at the end of the intervention. Social support will be measured through questions drawn from the Medical Outcomes Study and the National Social Life, Health, and Aging Project questionnaires. Psychological morbidity will be measured through Goldberg's General Health Questionnaire, and Health-related Quality of Life will be measured through the EuroQoL questionnaire. Information on visits to the primary care center in the years before and after the intervention will be obtained from the electronic records of the primary care centers; 3) A cost-utility analysis, which will be conducted from a health system (primary care) perspective, including direct costs of the program and the primary care health services used. The effects of the intervention will be measured on quality-adjusted life years. Discussion: There is an urgent need for studies assessing the effectiveness and the efficiency of potential interventions to reduce social isolation among older persons. The results of this study will help to fill the knowledge gap in this area and might be especially useful for the development of social and public health policies and programs for older people in disadvantaged neighborhoods in urban areas