City Of Douala Research Articles

Advancing urban mobility in developing countries: A mobile RSU approach for sustainable transportation

AbstractThe rapid and uncontrolled urbanization of cities in developing countries has engendered a plethora of urban mobility issues, including traffic congestion, accidents, and air pollution. To address these challenges, contemporary urban mobility trends are incorporating innovative technologies and sustainable governance practices. This article investigates how urban managers can leverage the opportunities presented by cost‐effective technologies and the management of urban data to enhance urban mobility in developing countries. Within this discourse, an RSU‐based approach is proposed that employs motorbike taxis for inter‐vehicular communication, given their status as the most widely used form of public transportation. This approach substantially diminishes investment costs and reinforces the sustainability of urban mobility. Through the implementation of this solution, a noteworthy reduction is anticipated in the emission of gases such as CO2, and NOx, known contributors to climate change and various respiratory diseases. To validate the efficacy of the proposed solution, four distinct scenarios are scrutinized in a case study centered on the city of Douala in Cameroon, utilizing tools such as OMNET++, SUMO, Veins, and INET. The proposed framework offers significant benefits in terms of environmental sustainability and operational efficiency. It enables a 10% reduction in CO2 emissions, a 15% reduction in NOx emissions, an 11% drop in fuel consumption, and a 15% reduction in waiting time in traffic jams. The envisaged solution aims to aid urban managers in their decision‐making processes, specifically in advancing sustainable urban mobility. Through the adoption of this approach, cities in developing countries can mitigate challenges associated with urban mobility and enhance the overall well‐being of their residents.

Urban Road Transport Infrastructure Planning and Development Implications on Socio-Economic Growth in the City of Douala, Cameroon

Cities are the major contributors to socio- economic growth with easy access to amenities which stem through road transport infrastructure development. This study was conducted to assess urban road transport infrastructure planning and examine development implications on socio-economic growth in the City of Douala. A descriptive research design was used with primary and secondary data collected and analyzed using descriptive and inferential statistical techniques. Results revealed that, transport infrastructure in Douala have been structured through urban development planning policy which influences surface spatial expansion of socio- economic activities. The planning policies have contributed to the rapid expansion and growth through the initiations of master plan, land use plan and sector plan. Infrastructural development on road transport depicts a physical expansion and construction of road networks which influences the socio-economic growth of the study area. Stakeholders’ actions on construction, reconstruction and rehabilitation, investments and maintenance of road infrastructure have helped to curb down some transportation challenges and creates easy access to facilities within different sectors of the study area. However, road transport infrastructure which is well-developed boasts socio-economic activities and growth. The state of road transport network, its diversity and characteristic features is defined by its prevalence within different areas in Douala. Contrarily, other transport infrastructures which are not functioning appropriately due to lapses in physical planning possess enormous implications on transportation in the study area. The conclusion drawn was that the manner in which urban planning policies are implemented determines the level of development in road transport infrastructure and socio-economic growth of Douala. The study recommends an effective application of planning policies to be integrated by implicating all the actors of urban managers and transportation planners for improved growth in the study area.

Evaluation of the Effectiveness of Existing Preventive Fire-Fighting Measures in the City of Douala, Cameroon, to Improve Decision-Making and Public Safety

The storage of hydrocarbons in urban areas poses significant risks to local populations, including the potential for fire, explosion, groundwater contamination, and air pollution. The objective of this study is to evaluate the efficacy of current fire prevention and suppression strategies in the city of Douala. The study will be approached by first identifying, geolocating, and characterizing urban firefighting equipment. Subsequently, a proposal will be put forth for a response system to safeguard the city in the event of a catastrophic fire at a service station. In order to achieve this objective, the current regulatory framework governing the location of FH facilities was subjected to a thorough examination. Subsequently, pivotal compliance factors were identified, operationalized, and an audit checklist was formulated. A safety questionnaire was utilized to assess the equipment within service stations. GPS technology was employed to record the GPS coordinates of the FHs. GIS10.3.1 software was utilized to evaluate the BI distribution model. The data obtained from the questionnaires were analyzed using SPSS20.0 software, which revealed that the 142 BIs studied were essentially randomly distributed across the following neighborhoods. The results of the election yielded the following results: Bonamoussadi 27 (19%), Bonandjo 19 (13%), Bali 02 (1%), Deido 09 (6%), Akwa Nord 03 (2%), Bonamoussadi 18 (12%), Makepe 18 (12%), and B. The remaining 5% is distributed among the following: Assa, Bepanda, Cité-Sic, Ndogbong, Cité des Palmiers, Bonaberi, and New-Bell. Of the 142 FH identified, 30 (21.12%) lack water, and 4 (2.81%) have a flow rate of less than 30 m³/h with a dynamic pressure of less than 1 bar. Seventeen (11.97%) are inaccessible; 79 (55.63%) are operational; five (3.52%) are challenging to operate; and seven (4.92%) are situated within a private enclosure. The response time of the fire department is inadequate for all stations situated more than 3 km from their base in Ngondi-Douala. Only 17 (11.52%) of the stations are situated at distances of less than 5.83 km, which is conducive to efficient intervention. In contrast, 134 (88.74%) of the stations are located at distances of 5.83 km or more from the fire department base, which is not conducive to efficient intervention. The results indicate that the BIs are situated at considerable distances from the stations. Notably, the Total Laquitinie station is the sole city station with a FH located at its entrance. The database developed in this study could serve as a valuable resource for policymakers to inform appropriate action.

Ecological Implications of Seasonal Variations in Physicochemical Parameters and Phytoplankton Community in an Effluent‐Receiving Wetland in the Gulf of Guinea, Cameroon

ABSTRACTPhysicochemical parameters, chlorophyll a (Chl a) concentration, and phytoplankton community structure were assessed in the Wouri estuarine mangrove sector of the Douala Bassa Industrial Zone of Cameroon over two seasons. Three sets of water samples were collected from 10 sites for these analyses. Some physicochemical parameters were measured in situ using multiparameter equipment (HANNA 8289). The data were subjected to analyses of significant difference by an independent sample t‐test. Correlation and principal component analysis conducted between variables Temperature, salinity, total dissolved solids (TDS), resistivity, and turbidity showed a strong seasonal variation among sites. Mean Chl a concentration (3.7–48.29 µg/L for dry and 0.1–20.1 µg/L for rainy season) revealed that most sites were eutrophic, with the Euglenophycean index less than 1 in all the sites. Phytoplankton species richness exhibited seasonal and spatial variation, with a total of 74 taxa and 51 taxa for the dry and rainy seasons, respectively. The division Bacillariophyta was the most abundant, with 19 families and 24 species during the dry season and 17 families and 16 species during the rainy season. Other phytoplankton divisions present included Chlorophyta > Cyanophyta > Charophyta > > Myzozoa > Euglenophyta in the dry season; the less diverse divisions in the rainy season were Rhodophyta > Cryptophyta > Xanthophyta > Euglenophyta. High concentrations of nutrients and the presence of eutrophic species such as Microcystis aeruginosa suggest pollution and a need to monitor activities carried out along the water course with respect to the quantity and quality of industrial effluents discharged into the stream. The observed eutrophication explains the noxious odor across the city of Douala, especially during the dry season. The human health implications could be severe, with communities dependent on this contaminated stream for fish and other necessities a scenario that repeats itself in communities dependent on urban wetlands in industrial zones globally.

Prevalence and impact of primary headaches among students aged 8-12 years in Sub-Saharan Africa: Cameroon experience.

The present study aimed to investigate the prevalence and impact of primary headache among students aged 8-12 years in the city of Douala (Cameroon). From January to May 2022, a cross-sectional study was conducted in 52 primary schools randomly selected from five districts in the city of Douala. The study population consisted of primary school students in level III classes. The diagnosis of primary headache was made according to the International Classification of Headache Disorders, 3rd ed (ICHD-3) criteria and the paediatric version of the HARDSHIP questionnaire was used for recruitment. In total, 2056 students participated of whom 55.9% (n = 1149) were female, with a median age of 11 years. The prevalence of headache in the last 12 months was 85.7% (n = 1762), that of migraine was 26.1% (n = 536) and that of tension-type headache (TTH) was 15.1% (n = 311). Regarding the impact of primary headaches, 176 (32.8%) migraineurs reported absenteeism from school compared to 70 (22.5%) students with TTH (p = 0.03) and 309 (57.6%) migraineurs had a break in their activities compared to 147 (47.3%) students with TTH (p < 0.01). Primary headaches are common among students aged 8-12 years in the city of Douala. They are responsible for a considerable impact on children and their family, particularly for migraineurs.

Assessing the performance of a monocrystalline solar panel under different tropical climatic conditions in Cameroon using artificial neural network

To implement the European Union (EU)-Africa Green Energy Initiative in Cameroon to boost the renewable energy sector, we model the performance of a 500 W monocrystalline solar panel in major cities of Cameroon located in different climatic zones to select the best location for the installation of a solar farm. We also evaluate the contribution of seasonal and weather variability to the amount and stability of power generated by the panel using the artificial neural network (ANN). The ANN model was used to train and test the ERA5 hourly data for Bamenda. The model was then used to estimate Photovoltaic (PV) output in Douala, Yaounde, Ngaoundere, Garoua, and Maroua with a mean absolute error of 4.109 × 10−5, 4.699 × 10−5, 3.563 × 10−5, 3.106 × 10−5, and 3.083 × 10−5 kW, respectively. The results show that the ANN can capture the influence of weather variability on the generated output power. Cloud cover and rainfall are found to negatively affect the amount and stability of generated power in the lower latitude cities of Douala and Yaounde compared to the northern cities, with these effects being stronger in the rainy season than in the dry season. Garoua followed by Maroua are proving to be the best locations for installing a solar park in terms of the amount and stability of electricity generated throughout the year. The Cameroonian government, its EU partners, and other stakeholders involved in the development of solar energy in the country will be able to use the results of this study for better decision-making.

A Semiotic Analysis of Nonverbal Linguistic Signals Used On Billboard Posters as a Means of Creating Public Awareness During the Covid-19 Pandemic in Douala

This paper examines the use of nonverbal linguistic signals on billboard posters during the Covid-19 pandemic in Douala. It has been noticed that nonverbal signals such as sweating, wearing a nose mask, washing of hands with clean running water and soap and standing two metres apart from each other and the use of colours such as white and red among others play an important role in the way human beings communicate especially during a period of crisis. Although it is nonverbal, this means of communication acts more than the verbal one. This work focuses on nonverbal linguistic features used on billboard posters in the city of Douala as a means of creating public awareness in relation to the Covid-19 pandemic so that the contamination and mortality rate can be reduced. This study is of great value because it demonstrates how people should live during a pandemic era without being contaminated. This research uses a qualitative research design. The researcher culled some pictures that were pasted on billboards during the crisis (2020-2021) on the streets of Douala. Insight was drawn from Barthes (1964) theory of semiotics. The findings indicated that people washed their hands with clean running water and soap, they wore masks, arrows were used to show how people should stand with others in public, colours such as red was used to show how dangerous this virus is and the white colour was also used to indicate that people need to be clean during this period so that they can minimise the chances of being contaminated. Capitalisation was used either in red or black to attract the attention of the public to the messages written on the billboards. The researcher concludes that people should develop the culture of reading public notices especially billboard posters during epidemics and pandemics so that they can save their lives.

Numerical computation of heat transfer, moisture transport and thermal comfort through walls of buildings made of concrete material in the city of Douala, Cameroon: An ab initio investigation

The buildings of the city of Douala in Cameroon have been experiencing degradation for several decades due to the climate characterized by high humidity and oppressive heat. As a result, large grayish or black stains can be observed on these buildings. We sometimes witness the subsidence of the slab of the balconies, the cracking of the walls and the collapse of the buildings worn by the humidity. These damages are generally caused by infiltration and capillary rise. In addition, it has been demonstrated that people living in damp buildings are at risk of illnesses such as asthma and lung infections. Therefore, the novelty of this work is threefold: (i) it proposes for the very first time a numerical study of the transport of humidity and heat through the porous walls of buildings constructed with concrete material, the main construction material in the city of Douala; (ii) It was determined what level of indoor thermal comfort was appropriate for sleeping inside a real three-dimensional G+1 complex residential building constructed with concrete blocks; and (iii) Using the geographical coordinates, and time data, the sun radiation's direction of incidence was assessed throughout the simulation. The computation was performed using Comsol Multiphysics 6.0 software. The distributions of temperature, relative humidity as well as moisture level were presented at various periods. It appears from the results that face to this high humidity, the concrete material retains a large quantity of water for a considerable periods of time, which weakens the steel reinforcement of concrete which is corroded by rust. The computation of thermal comfort in the 3D building showed that the various rooms of the building were not comfortable during the night since temperature inside the building increased progressively due to diffusion of heat. In addition, the numerical solutions indicated that the energy stored within the walls diffused from the external walls to the internal walls during the night. It was also demonstrated that the walls of the building were warmer than the windows, doors and the roof at the computational times, which simply revealed a greater storage capacity of heat in the concrete blocks material. The findings highlighted that the temperature decreased rapidly in a thickness of 0.06 m of the concrete block during the nine days and this decrease was attenuated in the second part of the thickness of the concrete block (0.14 m).

Estimation of return dates and return levels of extreme rainfall in the city of Douala, Cameroon

The problem of extreme phenomena with a more precise estimation of their return periods for early warnings, notably to preserve the safety of populations and properties, arises all over the world. This work develops another aspect in the estimation of Return Levels (RLs) and Return Periods (RPs) of extreme precipitation in particular and natural risk in general. In particular, it gives the Return Dates (RDs) with their Confidence Intervals (CIs). The RPs, the RLs and their CIs for extreme rainfall were also investigated. These estimates were made by approaching the peak over a threshold chosen by the Generalized Pareto Distribution (GPD). The CIs of RPs and RLs were determined by the Delta method. The daily rainfall data used were obtained from the data of the synoptic report for the period 2011 to 2021 for the Douala weather station (more details can be found on http://www.ogimet.com/guia.phtml.en). To validate the methods used, real cases of floods occurred in Douala city were considered: for example, a local press compiled flood dates and mentioned that a flood occurred on the April 16, 2013 in this city. Following the data of synoptic report, the corresponding amount of rainfall was around 150 mm. The results obtained have shown a RD on the August 12, 2014. The confidence intervals of return levels and return dates determined by the Delta method were [131.66, 168.456] and [June 23, 2014, January 02, 2015], respectively. These results are in agreement with the data of synoptic report since the rainfall amounts was 132.2 mm (belonging to the confidence interval of return levels), on the August 11, 2014 (belonging to the confidence interval of return dates). These predictions of RDs and RLs with their CIs, at reasonable time scales, can help for efficient management of floods and thus, improve early warnings for safety of populations and goods.

Real-time air quality monitoring based on locally developed unmanned aerial vehicle and low-cost smart electronic device

This article deals with the development of real-time air quality monitoring based on Unmanned Aerial Vehicles (UAVs) and low-cost Internet of Things (IoT) devices. This investigation aims to design and develop an UAV-based platform that can monitor a large number of air pollutants in real-time with high spatial and temporal resolution. The proposed environmental monitoring system consists of five main elements, namely the UAV, sensors, data storage module, programmable card, and IoT communication module. Estimated pollutants such as particulate matter (PM2.5) and toxic gases (carbon monoxide CO, nitrogen dioxide NO2, and carbon dioxide CO2) are detected by low-cost sensors. The ZigBee wireless protocol is used for communication between the PC and UAV. This work is carried out to assess the air quality in urban areas, given the heavy road traffic and the emissions of some companies. The data analyzed were collected from December 2, 2022 to January 3, 2023, in two major cities of Cameroon, Douala and Kribi. The periodic average values of the detected pollutants are 222 ± 22 μg/m3 and 85.7 ± 8.6 μg/m3 for PM2.5, 560.8 ± 1.0 ppm and 555.6 ± 1.0 ppm for CO2, 4.2 ± 0.2 ppm and 0.7 ± 0.1 ppm for NO2, and 27.6 ± 2.8 ppm and 4.5 ± 0.5 ppm for CO in Douala and Kribi respectively. This made it possible to have an air quality index (AQI) of 444.2 for Douala City and 171.3 for Kribi City. These high values indicate poor air quality during the measurement period.

Les défis de la prise en charge de la variole du singe dans un pays en voie de développement : cas du Cameroun

International interest has been focused on Monkeypox since July 2022, due to multiples cases reported outside Africa. We report a case that occurred in Cameroon during this period. A 40-year-old Patient, heterosexual, living in Tombel in the southwest of Cameroon, HIV positive, consulted on 02/10/2022 for umbilicated, confluent vesiculo-pustular lesions, confluent on the face and scalp with palmo-plantar involvement, without lymphadenopathy, febrile, and evolving for 2 weeks. The diagnosis of Monkeypox was made based on a positive PCR test from on a skin sample revealing the Monkeypox clade 2 virus. Under treatment, the evolution was favourable after 17 days. We report the first confirmed case of Monkeypox in the city of Douala. The major challenge for the government would be to develop diagnostic and response strategies, to contain and neutralize the disease.

Estimation of energy demand and carbon emissions for the road transport sector: A case study of Douala, Cameroon

Road transport is one of the main causes of air pollution around the world. Nowadays, the notion of sustainable development is one of the major pillars for a healthy environment. However, faced with its major challenges, it is more than necessary and important to understand a set of elements which contribute to better understanding the level of planning for sustainable road transport. This study aims to estimate energy demand and greenhouse gas emissions, namely from road CO2 transport, for the city of Douala in Cameroon from 2010 to 2035. In order to achieve our objective, we used the Long range Energy Alternative Planning (LEAP) model. Based on the LEAP model, the estimates were evaluated based on three scenarios Business As Usual (BAU), Energy Optimization and Mitigation (EOM) and Sustainability Mobility (SM). The aim of this work was to identify suitable potential policies with a view to reducing energy consumption and emissions carbon dioxide (CO2) for road transport in Douala. The results tell us that the EOM and SM scenarios have advantages over the BAU scenario with the SM scenario being more optimistic than the other two scenarios. In addition, the SM scenario has a growth rate of 87.408 % in energy demand smaller than the other two scenarios BAU and EOM respectively 151.598 % and 132.073 %. We also note that the SM scenario contributed to a reduction of 60.661 kilo ton emissions of CO2 less than the BAU scenario. At present, with a view to reducing energy consumption and reducing carbon emissions, road vehicles in circulation in the city of Douala should emphasize structural optimization measures through the use of clean energy by promoting the use of biofuels in mass transport, eliminating old cars and finally considering improving energy efficiency through the implementation of technological development in the automobile sector. Policy makers must take this study into consideration in order to better integrate the notion of energy sustainable road transport.

A Novel Deep Learning-Based Data Analysis Model for Solar Photovoltaic Power Generation and Electrical Consumption Forecasting in the Smart Power Grid

With the installation of solar panels around the world and the permanent fluctuation of climatic factors, it is, therefore, important to provide the necessary energy in the electrical network in order to satisfy the electrical demand at all times for smart grid applications. This study first presents a comprehensive and comparative review of existing deep learning methods used for smart grid applications such as solar photovoltaic (PV) generation forecasting and power consumption forecasting. In this work, electrical consumption forecasting is long term and will consider smart meter data and socioeconomic and demographic data. Photovoltaic power generation forecasting is short term by considering climatic data such as solar irradiance, temperature, and humidity. Moreover, we have proposed a novel hybrid deep learning method based on multilayer perceptron (MLP), long short-term memory (LSTM), and genetic algorithm (GA). We then simulated all the deep learning methods on a climate and electricity consumption dataset for the city of Douala. Electrical consumption data are collected from smart meters installed at consumers in Douala. Climate data are collected at the climate management center in the city of Douala. The results obtained show the outperformance of the proposed optimized method based on deep learning in the both electrical consumption and PV power generation forecasting and its superiority compared to basic methods of deep learning such as support vector machine (SVM), MLP, recurrent neural network (RNN), and random forest algorithm (RFA).

A moderately chocked estuary: Influence of a constriction on the water level variations of the Wouri estuary (Cameroon)

We study the water-level (WL) evolution in the Douala basin (DB), a sub-basin of the Wouri estuary, separated from the ocean by a natural constriction and influenced by tides and river inflow. Our objective is to assess whether floods in Douala city could result from water overflow from the Douala basin due to Wouri river floods. We first evaluate the constriction’s damping effect by analyzing tide amplitude variations from the ocean to the basin. A simplified model for basin WL variation is developed, incorporating a dissipation parameter (Г) that is evaluated using weak tidal amplitude modulation from the ocean to the basin over the dry season of 2023. Results in the DB reveal nondimensional choking-parameter (P) values of 12–19, indicating moderate dissipation. The basin's relatively small area results in a nondimensional river discharge parameter (S) of 0–12, indicating high river discharge regimes. Subsequently, the model is used to evaluate the mean and maximum WL, as well as tide amplitude variations of the DB, as functions of river flow and ocean tides. The mean WL increases, but the maximum tide amplitude decreases as river input increases. The maximum WL in the basin always exceeds the maximum amplitude of ocean tides but is only significantly higher when river input is above 1000 m3/s. In current conditions, where maximum observed river input is around 1800 m3/s, it is unlikely that flooding will extend beyond the basin borders into the city of Douala. For a moderate increase (20%) in future maximum river fluxes, it is also unlikely that the DB will overflow into Douala city. Only a drastic increase in mean ocean level and river fluxes (which are possible scenarios associated with climate change) could potentially lead to a significant rise in basin WL, resulting in severe flooding.

Does culture empower inclusive finance? Empirical investigation into small business in Cameroon

The issue of culture is becoming ever more interesting, especially when interconnected with other business factors like finance. Although intriguing, the relationship between culture and finance has long been neglected. Unlike existing research, this article aims at assessing the impact of culture on financial inclusion and financial literacy among Cameroonian small business managers. In this quantitative investigation, the indices are built using Principal Component Analysis (PCA), and the estimation is done using Ordinary Least Squares (OLS). The data used is from a research survey on 161 small enterprises in the cities of Douala, Bafoussam, Foumban, Foumbot, and Dschang. The findings demonstrate that organizational culture, in contrast to its social component, is positively and strongly associated with financial literacy and financial inclusion. Additionally, firm and manager variables like age, turnover variation, and education level significantly explain these financial variables. Thus, it is essential to promote organizational culture in Cameroonian businesses.

Predictors of prolonged length of hospital stay and in-hospital mortality in patients aged 1–24 months with acute bronchiolitis in Douala, Cameroon

IntroductionIn Cameroon, acute bronchiolitis has been reported as the third commonest lower respiratory infection and is usually associated with low mortality. Nonetheless, respiratory distress associated with non-adherence to management guidelines can prolong hospital stay. This study aimed to explore predictors of prolonged hospital stay (≥ 5 days) and mortality in patients aged < 2years hospitalised for acute bronchiolitis.MethodologyWe conducted a retrospective cohort study at three paediatric units in the city of Douala, Cameroon. Factors associated with prolonged hospital stay and mortality were determined using multivariable linear regression model. Threshold for significance was set at p ≤ 0.05.ResultsA total of 215 patients with bronchiolitis were included with mean age of 6.94 ± 5.71 months and M/F sex ratio of 1.39/1. Prolonged hospital stay was reported in 46.98% and mortality in 10.70% of patients hospitalised for bronchiolitis. Factors independently associated with prolonged hospital duration were oxygen administration [b = 0.36, OR = 2.35 (95% CI:1.16–4.74), p = 0.017], abnormal respiratory rate [b = 0.38, OR = 2.13 (1.00-4.55), p = 0.050] and patients presenting with cough [b = 0.33, OR = 2.35 (95% CI: 1.22–4.51), p = 0.011], and diarrhoea [b = 0.71, OR = 6.44 (95% CI: 1.6-25.86), p = 0.009] on admission. On the other hand, factors independently associated with mortality were age of the patient [b= -0.07, OR = 0.84 (95% CI: 0.74–0.97), p = 0.014] and oxygen administration [b = 1.08, OR = 9.64 (95% CI:1.16–79.85), p = 0.036]ConclusionAcute bronchiolitis represented 1.24% of admissions and was common in the rainy season, in males and 3–11-month-old patients. Management guidelines were poorly respected. Prolonged length of stay was reported in half of the patients hospitalized and mortality was high, especially in younger patients and in patients receiving oxygen.

Refusal and hesitation regarding vaccination against COVID-19 in Douala, Cameroon

vaccination is one of the strategies the World Health Organization recommends to reduce the burden of COVID-19. However, many African countries like Cameroon have low COVID-19 vaccination coverage. The purpose of this study was to investigate the reasons for the refusal of the population of the city of Douala to be vaccinated against COVID-19. we conducted a cross-sectional and analytical study in Douala from February 10 to May 31, 2022. Participants, aged at least 21 years and residing in the city of Douala, were interviewed. Associations between the variables of interest were measured using Chi-square and Fisher tests, with a 95% confidence interval. a total of 1555 people were included in the study. Only 168 (11%) had been vaccinated. The proportion of vaccine refusal was high, with 711 (45.7%) refusing, 640 participants (41.1%) hesitating, and 204 people (13.2%) being in favor of COVID-19 vaccination. The main reasons for refusing anti-COVID-19 vaccination were fear of adverse effects (406; 44.8%), lack of information about vaccines (331; 36.5%), and lack of confidence (302; 33.3%). Factors associated with vaccine refusal were religion (p=0.026) and level of education (p=0.002). this study revealed low COVID-19 vaccination coverage in Douala, with a significant proportion of refusal and hesitation towards vaccination. Communication strategies should take into account the reasons and factors associated with refusal.

PARTICIPATORY MAPPING AND DELIMITATION OF FLOOD ZONES IN DOUALA, CAMEROON

The spatialization of geographical phenomena is now based on geomatics methods and tools. This trend, which has become widespread in research circles, invites us, beyond the rendering of results, to question their relevance. Indeed, the results thus obtained are far from being realistic for reasons related to the quality of the analysis data but especially to the choice of the levels of observation. These weaknesses impose on African geographers in general and Cameroonians in particular, a paradigm shift. Instead of the work of a researcher/engineer-expert imposing a vertical vision of the territory, an approach that reverses the process could make it possible to reposition local populations in the production and spatialization of geographic information. No one better than the latter could understand and assess the constraints and vulnerabilities they face. Participatory mapping as a methodological journey integrates spoken language into a map, with the aim of giving substance to the voices of those who are poorly represented or not very visible, thereby facilitating dialogue and negotiations. Faced with what could be considered as drifts of the all-digital, is it relevant to entrust the pencil to the actors who practice the territories subjected to the phenomena subject to geographical representation? This study focuses on the development of a methodological framework for participatory mapping, based on the example of the risk of flooding in a watershed of the city of Douala. The envisaged approach is made possible thanks to semi-structured interviews based on the model of cartographic discussion groups. It emerges from this experience that the methodological approach of participatory mapping is feasible, reliable, less restrictive and moreover reproductive in several territories.

Prediction of pulmonary tuberculosis treatment outcome in a sub-Saharan African context.

Failure to treat many pathogens is a concern. Identifying a priori, patients with potential failure treatment outcome of a disease could allow measures to reduce the failure rate. The objectives of this study were to use the Scoring method to identify factors associated with the tuberculosis unsuccessful treatment outcome and to predict the treatment outcome. A total of 1,529 patients with pulmonary tuberculosis were randomly selected in the city of Douala, Cameroon, this sample was randomly split into two parts: one subsample of 1,200 patients (78%) used as the Development sample, and the remaining of 329 patients (22%) used as the Validation sample. Baseline characteristics associated with unsuccessful treatment outcomes were investigated using logistic regression. The optimal score was based on the Youden's index. HIV positive status, active smoker and non-belief in healing were the factors significantly associated with unsuccessful treatment outcomes (P#x003C;0.05). A model used to estimate the risk of unsuccessful treatment outcome was derived. The threshold probability which maximize the area under the ROC curve was 18%. Patients for whom the risk was greater than this threshold were classified as unsuccessful treatment outcome and the others as successful. HIV positive and active smoking status were associated with death; the non-belief in healing, youth and male gender associated with lost-to-follow-up, TB antecedent and not having TB contact associated with therapeutic treatment failure. To increase the tuberculosis treatment success rate, targeted follow-up could be taken during the treatment for TB patients with previous characteristics.

Wind data modeling and energy mapping of the wind potential in the city of Douala (Cameroun)

This work helps in the implementation of wind energy projects in the city of Douala. Wind data used (speed and direction) were collected from January 1, 2020, to December 31, 2020, at a height of 10m. The use of wind speed distribution laws allowed us to obtain predictions of the available wind energy on-site at different altitudes. Then, the wind direction is established for the orientation of the wind turbines and the turbulence analysis is done to highlight the exploitable wind periods. The results show that harnessing wind energy is possible on site from 10 AM to 06 PM. The wind potential at 138 m height has an average speed of 8.15 m/s for an overall energy density of 749.78 W/m2 for roughness class 0, and an average speed of 3.7 m/s for an overall energy density of 69.118 W/m2 for roughness class 4. The wind turbines will be installed in front of the north-north-east direction between 15 and 25°. Finally, the energy mapping of the city's wind resources allows us to estimate the total energy available at a reference height.