Articles

The Mambaka watershed is extends between latitudes 1 3°45'E and 14°15'E and longitudes 7°16'N and 6°45'N. The geology, various tectonic and structural events that have affected the Adamawa Plateau in Cameroon make it rich in multi-substance mining. The objective of this study is to map rare earth (REE) geochemical anomalies in the sediments of the watershed streams west of Mambaka, and to trace their origins and geochemical processes. Predictive maps from inverse distance interpolations (IDW), factor analysis (F1) or principal component analysis (PCA) and hierarchical bottom-up classification maps provided a better understanding of the central tendency, distribution and dispersion of REE in the samples and in the study area, based on standard deviation and variance values that generated two factors F1 (Ho-Tm-Er-Yb-Lu-Dy-Tb-Gd-Eu-Sm) and F2 (Pr-Nd-Ce-La-Sm) representing 92.44% of the total cumulative variance. The ratios Ce/Ce* > 0.78 and Eu/Eu* > 1 demonstrate positive anomalies in Ce and Eu, and clear differentiation. The normalized concentrations used to calculate fractionation ratios show that the values for LaN/YbN (0.58 to 1.34), LaN/SmN (0.61 to 0.88) and LaN/LuN (0.62 to 1.43) suggest higher fractionation in SS09 and lower fractionation in SS01. Similarly, the ratios La/Lu (61.71 to 143.46), La/Yb (9.00 to 20.72), La/Sm (4.02 to 5.83) and La/ Lu (61.71 to 143.46) confirm these higher ratios in SS09 and lower in SS01. The REE in the study area comes from hydrothermal processes based on high lineament densities at sampling points in igneous rocks with a mean ∑REE value of between 174-219 ppm.

The theme of the study that catches our attention is the initial conceptions of learners in Science and school performance; this theme is based on the competency-based approach in force in Cameroon, which is implemented in several African countries. Insofar as learning is not the accumulation of new knowledge but a cognitive reorganization of old knowledge experienced, it is therefore a question of knowing what is the influence of initial conceptions on the academic performance of learners in science. The objective of this research was to show that taking into account the initial conceptions of learners, Biology “SVT” has a lasting influence on learning and thus on the academic performance of learners. To achieve this objective, the study uses the mixed and quasi-experimental method, where two groups of learners were used: a control group and an experimental group. The experimental group was subjected to the teaching-learning system designed for this purpose, and in which the initial conceptions of the learners were taken into account according to do with or go against. In the light of the different hypotheses adopted and the different results of this study, it can be observed that the didactic consideration of the learners' initial conceptions improves their academic performance through the data of the experimental group. In relation to the field of education, this study shows that in order to enable learners to learn and build knowledge in the long term, their initial conceptions must be taken into account in concrete didactics; Otherwise, learning will be sporadic, learners' conceptions will be significant, which will lead to a learning defect perceptible by school failure.

The Douala-Edea National Park is a coastal protected area that opens to the Atlantic Ocean, and contains an abundant wildlife which finds a privilege habitat there, and certain taxa such as epiphytes, which are of particular interest for conservation. In many tropical forests, vascular epiphytes are one of the richest taxa, with major impacts on the nutrient and hydrological cycles. The aim of this research was to study the effect of the disturbance of habitat on the floristic composition of vascular epiphytes in the Douala-Edea National Park. This study was carried out between January - April 2021 in three types of disturbed habitats at the northern part of the park. Three plots of 100 m × 100 m dimensions were laid out across three ecosystems along the Sanaga river. The sampling method consisted in the direct observation of five adjacent transects of 100 m x 20 m dimensions inside each plot. Epiphytes species were evaluated on all trees of DBH ≥10 cm. Epiphytes' life-forms and the position on the host trees occupied by the epiphytes were also recorded. A total of 18 species belonging to 16 genera and 13 families were identified. <i>Culcasia</i><i> sp.</i> was the most common species with a relative frequency of 30.27%. Biological indicators were represented by Ferns, with four species, and Orchidaceae, with one species<i>.</i><i> </i>The epiphytes species richness was highest in the low disturbed habitat (13 species), and lowest in the highly disturbed habitat (8 species). Strict epiphytes were highly recorded in the low disturbed habitat (6 species), and were absent in the highly disturbed habitat. Hemi-epiphytes were the commonest life-form (12 species) in the highly disturbed habitat, and have been defined as indicators of the perturbation of the habitat. Canopy was mostly sollicitated by epiphytes in the low disturbed habitat (66.25%) than the moderate disturbed habitat (49.85%), and highly disturbed habitat (30.66%). It has been found that the different forest sites have an influence on the typology of epiphytic species, and therefore, epiphytic flora should be managed for the conservation of the biodiversity in tropical forests.

This study was designed to assess how primary identification markers affected social tolerance in a multi-tribal setting among a heterogeneous population. A sample of 312 participants was selected using the purposive sampling technique. A search of the literary documentation yielded three modalities of the dependent variable. Thus, data were collected from the Feeling Thermometer, Affirmative Action, and Multiculturalism scales. We assessed participants' levels of identification with identity markers to determine their impact on social tolerance. The findings suggest that measures of social tolerance are somewhat significantly influenced by Cameroonians' levels of affiliation with their key identity markers. However, tolerance decreases when tribal identity becomes stronger. Conversely, the effect of linguistic and religious identification forces on social tolerance varies depending on the object to be tolerated. These findings contribute to a better understanding of the determinants that influence social tolerance in a tribal setting.

This study took place in the Far North region of Cameroon. The general objective was to assess the floristic diversity of the undergrowth of Agrosystems in <i>Azadirachta</i><i> </i><i>indica</i>. The data were collected in 100 m long by 20 m wide transects surveyed in plantations of different ages. In total, 5 transects were carried out, ie a total area of 1 ha per site. The sampling bands were established using the compass, decameter, GPS and wires. The experimental set-up used was a 5-repetition split plot. A total of 7689 individuals divided into 9 families, 13 genera and 16 species have been identified. <i>Guiera</i><i> </i><i>senegalensis</i> and <i>Piliostigma</i><i> </i><i>thonningii</i> are the most common in terms of relative abundance. The analysis of the Family Importance Index (VIF) shows overall that the Combretaceae, and Mimosaceae are the most important in ecological terms. While those of the species show that <i>Guiera</i><i> </i><i>senegalensis</i>, <i>Combretum</i><i> </i><i>micranthum</i> and <i>Acacia</i><i> </i><i>nilotica</i> finally for the genera, it is Acacia, Guiera and Combretum which contains the most important ecological indices. The overall density of species within the plots varies between 129 and 105 ind / ha. The basal area varies from 2.02 to 3.88 m² / ha. The Importance Value Index (IVI) is of the order of 300 in the different plots. The floristic diversity of the undergrowth of Agrosystems (average ISH> 2) shows homogeneity and an even distribution between the different plots. Plots with similarity indices of less than 50% do not meet floristic affinity while similarity indices are high in plots with floristic affinities greater than or equal to 50%. The diameter structure showed a predominance of young individuals. This information drawn from the conclusion of the present study shows that they constitute an important argumentation of the advantages so that the services of agricultural development should be interested in the conservation and valuation of such an agroforestry system for the protection of the environment against the climate change mitigation and sustainable development of local communities.

This study raises the problem of the non-repayment of agricultural credits by producers who are members of the Community Growth Mutual (MC<SUP>2</SUP>), in this period of COVID-19. It questions the economic mores in force in most member countries of the Organization for the Harmonization of Business Law in Africa (OHADA), where credit has become difficult for small rural farmers; And refers to the theory of the vicious circle of poverty, which advocates an indispensable recourse to foreign capital in the event of financial breakdown, as a means of increasing capital. Since the capital of rural producers remains insufficient and their possibility of reinvestment decreases, then becomes zero because of agricultural credit. To understand the factors of the non-repayment of these credits, data were collected from 100 agro-sylvo-pastoral producers of the Bayangam group (West-Cameroon) of both sexes, aged at least 18 years, having obtained an unpaid credit from the MC<SUP>2</SUP> since 2019, and a manager of this microfinance institution. After analysis, it appears that beyond overproduction and anti-COVID-19 measures that lead to the missale or fall in prices on the market, the conditions of access to credit, the non-possession of acceptable guarantees, the misuse of the object of credit and the practice of financial cavalry by the borrower, as well as the rigidity of the procedures for prosecuting debtors significantly explain this non-repayment. It is associated with determinants such as age, level of education, marital status, type of agricultural activity of the debtor. Hence the need for flexibility of microfinance institutions vis-à-vis rural agro-sylvo-pastoral producers, who are severely affected by the economic shock of the COVID-19.

The present study raises the problem of empathy of caregivers vis-à-vis patients in a covid/post-covid context. It is based on the observation that health workers are increasingly invaded by excessive fear and persistence of COVID-19 contamination. This induces avoidance, a certain suspicion, persecution and indifference/coldness towards patients, and plunges them into a strong insidious emotional deficiency. These attitudes, which are significantly close to paranoid and phobic access, seem to gradually dominate therapeutic interactions within hospitals. Freudian and Rogerian psychoanalysis advocates empathetic/benevolent listening, positive consideration and unconditional acceptance of the patient as ethical and deontological indispensable principles for any therapeutic evolution. Thus, it is predicted that within hospitals, the current non empathetic attitudes of care towards patients have their origin in a generalized covid-phobic atmosphere that develops a quasi-dominant paranoia in caregivers. Using a subscale of caregiver's Covid-phobic quasi-paranoia, and the one of caregiver's empathy in a covid/post-covid context, the data were collected from 126 participants including 55 nursing assistants, 61 state-certified nurses and 10 doctors, chosen at random from the staff of three (03) health facilities in the city of Bafoussam, MIFI department, West Cameroon region, including one (01) public district medical center (CMA) and two (02) private hospitals (clinics). After analysis, the results obtained sufficiently demonstrate that within the health institutions of West Cameroon, the higher the professional level of the caregiver, the more the severity of his quasi-paranoid covid-phobic accesses is significant, and the less he expresses an authentic empathy towards the patients who arrive at the hospital. This implies that in this period of health crisis, caregivers must reinvest in a real function of providers of affectivity and relay of empathy at the bedside of the patient both in hospital and outpatient. Thus, a real systematical vaccination operation may insure their total immunity and better reduce their quasi-paranoid empathy in this generalized Covid-phobic context.

The present study poses the problem of the variations observed in the construction of identity strategies among schooled adolescent refugees. It starts from the observation that the latter express serious difficulties to be integrated into their host socio-cultural environments. Yet proximity to their original culture should guarantee continuity in the emergence of developmental skills initiated in their basic anthropomorphic universe. Paradoxically, they become dysfunctional in face of the demands of the host environment, and require the construction of identity strategies to adapt. Data collected from one hundred and eighty-four (184) central African refugee adolescents in the Lom-and-Djérem Division (Cameroon’s East-Region), show that in a situation of socio-emotional adaptation, age and sex are among the main factors of variation in the construction of these identity strategies.

Accurate estimates of above-ground biomass (AGB) and below-ground biomass (BGB) are essential for estimating carbon (C) balances at various geographical scales and formulating effective climate change mitigation programs. This study aimed to formulate specific allometric equations and carbon stock for <i>B.</i><i> </i><i>senegalensis</i> in Cameroon. Destructive sampling technique was used for harvesting and weighing the biomass of 40 individual trees. Allometric models were developed using biomass as dependent variable and tree dendrometric parameters as independent variables. The best models selected based with Adjusted coefficients of determination (Adj.R<SUP>2</SUP>), residual standard error (RSE) and Akaike's information criterion (AIC) were: ln (leaf biomass) = 0.08 + 0.31*ln (D<SUP>2</SUP>×H×ρ); ln (branch biomass) = 0.14 + 0.65*ln (D²×H×ρ); ln (stem biomass) = 2.03 + 1.32*ln (D²×H); ln (AGB) = 4.55 + 2.85*ln(D) and ln (BGB) =3.04 + 1.64*ln(D). The belowground biomass of <i>B.</i><i> </i><i>senegalensis</i><i> </i>represents on average 25 % of the total aboveground biomass. Aboveground carbon ranged between 7.09 ± 0.42- 9.01 ± 0.50 tC/ha; Belowground carbon ranged between 4.37 ± 0.26 - 7.11 ± 0.35 tC/ha; litter carbon ranged between 0.50 ± 0.02 - 0.95 ± 0.04 tC/ha; herbaceous carbon ranged between 1.05 ± 0.28 - 1.86 ± 0.20 tC/ha ; dead wood carbon ranged between 3.03 ± 0.40 - 8.98 ± 0.44 tC/ha; Soil Organic Carbon Stock varies between4.33 ± 0.79 - 6.14 ± 1.05 tC/ha ;Total carbon were 33.24 ± 4.28;27.40 ± 3.35;27.27 ± 3.27and 21.18 ± 3.00 tC/ha in site 3, site 2, site 1 and site 4 respectively.The specific allometric equation developed for <i>B.</i><i> </i><i>senegalensis</i> can be used in similar Sudano-Sahelian savannas to implement activities to reduce emissions from deforestation and degradation (REDD+) for the benefit of local carbon trading communities.

In the agroforestry systems of sub-Saharan Africa, the vertical and horizontal distribution of tree root biomass according to the soil profile is still poorly documented. The objective of this study is to verify the root distribution of four species of trees established in living hedges, namely, <i>Commiphora kerstingii</i>,<i>Erythrina sigmoidea</i>,<i>Ficus thonningii</i> and <i>Jatropha curcas</i> according to two types of soil (light soil and heavy soil) and three agroforestry technologies (fallows, wooded parks and plantations). The hedges were mostly monospecific in order to facilitate the identification of the roots. The experimental set-up is an entirely random factorial design with two factors. The evaluation of the distribution of tree roots was carried out using the profile method. To determine the different textural classes, a particle size analysis was undertaken in the laboratory. The results obtained show that the number of roots decreases rapidly after 30 cm of depth. The highest root densities are observed in the first 30 cm. Soil type has a slight effect (p <0.05) on rooting density in the last 30 cm of depth for all root classes, higher densities were obtained in light soil compared to heavy soil. <i>Commiphora kerstingii</i>stands out significantly by obtaining a higher number of roots than the other species for all classes. Among the technologies, the plantations showed the lowest root density at 0-5 cm and the highest at 55-60 cm. The root density was higher in the fallows. The results show that the root system is mainly concentrated near the stump.

The traditional electric grid of the City of Kumba has been experiencing a constant failure which leads inhabitant to experience constant blackout. This constant blackout persists and stays for a long time due to the lack of communication between equipment, consumer and supplier. Whenever there is a fault, the repairing agents walk along the feeder to find the fault. This manual fault finding increases the restauration time which leads to the augmentation of the blackout period. Factors responsible for the failure of the line are complex to be controlled. It is necessary to reduce restauration time by introducing Information and Communication Technologies (ICT) and sensing system in the grid and making it to be smart. ICT in this smart grid, sensors and smart meters are meant to assure two-way communication between the supplier and the consumer. They send real time information which is computed at the control center to optimize the entire grid. Distributed generation is also introduced in the system for two purposes. To complete the lag in power demand of the grid and to take over the supply when the main feeder is faulty. Various distributed generation sources studied led to the choice of solar power plants thanks to their low production of Greenhouse Gas (GHG) and availability of their resources in the city. A model has been proposed for the distributed generation and optimization of the smart grid. The system indexes obtained without distributed generation in the grid are different from that with. The difference in these indexes proved that the grid has been optimized. However, the reliability of the grid is enhanced after the introduction of distributed generation into the system. This enhancement in reliability declares that with distributed generation into the grid, the population of Kumba has a reliable power supply, which makes them to have energy throughout.

This study aimed to assess the floristic composition, vegetation structure and species associations of Cashew agro-ecosystems in the North region of Cameroon. The data were collected in 100 m x 20 m transect methods. An analysis of the data collected in the field was conducted around the diversity and richness of the flora, but also the structure of Cashew agro-ecosystems. For the analyzes of vegetation structure, tree density, basal area and biovolume were calculated. The inventory included trees with a dbh greater than or equal to 5 cm on an area of ​​1 ha per plot. The experimental device installed is a complete random Fisher block with five repetitions. A total of 7849 individuals in 17 families, 20 genera and 38 species were recorded<i>. </i>Species Important value of vegetation cover indicated that <i>Diospyros </i><i>mespiliformis</i><i>, </i><i>Anogeissus</i><i> </i><i>leiocarpus</i><i>, Annona senegalensis and Terminalia </i><i>laxiflora</i> are the most represented. Combretaceae are the most ecologically important families. Additionally, the grouping of species into four subdivisions showed that the Shannon diversity index varies from 2.18 ± 0.09 - 3.47 ± 0.17 bits, Pielou index vary from 0.98 ± 0.01 - 0.99 ± 0.01, Simpson's index ranges from 0.70 ± 0.18 - 0.93 ± 0.11, density ranges from 102 ± 1.92 - 128 ± 6.36 indiv/ha, basal area ranges from 2.02 ± 0.31 - 12.68 ± 2.01 m²/ha, biovolume ranges from 11.58 ± 1.29 - 68.03 ± 13.21 m<SUP>3</SUP>/ha. The Sörensen similarity index is very high with floristic affinities greater than or equal to 90%. The diameters and heights structure show a predominance of young individuals for the diameter and height classes on all plots. The most represented species associations are legumes (<i>Arachis </i><i>hypogeae</i>: 40.54%) and native fruit trees (<i>Vitellaria </i><i>paradoxa</i>: 15%). These results show the contribution of Cashew agro-ecosystems in biodiversity conservation.